DOI: 10.3897/jucs.168955

Authors: Davut Çulha

Abstract: Large Language Models (LLMs) have shown impressive capabilities in natural language understanding and reasoning; however, their internal conceptual organization remains largely opaque. This study introduces a novel prompt engineering approach to explore the latent conceptual spaces of LLMs by identifying maximally divergent conceptual regions. It draws on the conceptual spaces framework, in which knowledge is represented as geometric regions defined by quality dimensions. Within this framework, a proxy metric referred to as the conceptual divergence count is proposed. This metric represents the number of maximally divergent conceptual regions identified through structured prompts. Although the metric does not measure dimensionality in the geometric or architectural sense, it serves as an indicator of a model’s conceptual diversity. The method is applied to a range of LLMs, including models from the Gemini, GPT, and Claude families, as well as additional models such as Llama-3.3-70B-Instruct, Mistral-7B-Instruct-v0.3, Gemma-3-12B-IT, and Grok-3. The results show substantial variation in diversity, with gemini-2.5-flash-preview-05-20 achieving the highest value of 91 and claude-3-7-sonnet-20250219 recording the lowest value of 7. These findings suggest that diversity, as measured by this method, may provide insights into the internal organization of conceptual representations. While the metric is to be an indicator of a model’s factual knowledge structure, providing complementary insight into its internal organization, it does not directly measure knowledge accuracy. The proposed approach contributes a geometric perspective to the evaluation of LLM knowledge, complementing existing benchmarks and supporting interpretability.

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DOI: 10.3897/jucs.167412

Authors: Yanling Chen

Abstract: In this paper, we show the problem of two-party privacy-preserving record linkage (PPRL) can be seen as an identification problem in Information Theory. We propose to apply the identification codes that are designed for identification via channels to the problem of PPRL, due to their advantage in the performance analysis, especially on a quantitative evaluation of the privacy. Note that for the PPRL, linkage quality is typically evaluated experimentally, whilst for privacy, there are so far no commonly accepted privacy measures available that allow an objective evaluation. Our approach of identification code provides an objective evaluation on both linkage quality and privacy based on parameters of employed identification codes.

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DOI: 10.3897/jucs.112725

Authors: Edward Kai Fung Dang, Robert Wing Pong Luk, Qing Li

Abstract: Traditional information retrieval models mostly adopt a term independence assumption and are based on single terms or unigrams. Past efforts have attempted to go beyond this assumption, such as by using contiguous terms (i.e. word n-grams) or terms appearing in proximity. One such approach employs pseudo-relevance feedback (PRF) in an extended BM25 model, with an expanded query containing bigrams and proximity word pairs besides unigrams. However, the benefit of this approach over the traditional unigram PRF remains inconclusive. We speculate the uncertain effectiveness of bigram PRF in this past work is due to: (1) The new bigrams obtained from the expanded query may be formed by pairing unigrams drawn from different documents. These are potentially noise instead of relevant concepts; (2) The collection statistics of n-grams needed to calculate the document ranking functions, such as their document frequency, is not available in retrieval. Only estimates of these quantities are used instead. We suggest that these issues may be overcome by extracting word n-grams as single units in query expansion, and employing a document index that contains both unigrams and word n-grams. We demonstrate the approach for the case of bigram PRF in an extended BM25. Retrieval experiments are conducted on a range of standard test collections. For the majority of tested collections, the difference between values of the evaluation metrics (Mean Average Precision and the precision-oriented NDCG@20) obtained by our bigram PRF and the unigram PRF baseline is not statistically significant. Thus, our bigram PRF fails to improve over unigram PRF robustly across collections. An analysis of our results reveals ‘query drift’ due to bigram query expansion terms that represent too-broad topics as a cause for the failure of our approach.

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DOI: 10.3897/jucs.97822

Authors: Herminia Beatriz Parra de Gallo, Marcela Vegetti

Abstract: This paper shows the research conducted to respond to a continuous requirement of justice regarding the application of scientifically supported forensic tools. Considering ontological engineering as the appropriate framework to respond to this requirement, the article presents OntoFoCE (Spanish abbreviation for Ontology for Electronic Mail Forensics), a specific ontology for the forensic analysis of emails. The purpose of this ontology is to help the computer expert in the validation of an email presented as judicial evidence. OntoFoCE is the fundamental component of the ObE Forensics (Ontology-based Email Forensics) tool. Although there are numerous forensic tools to analyze emails, the originality of the one proposed here lies in the implementation of semantic technologies to represent the traceability of the email transmission process. From that point on, it is possible to provide answers to the items of digital evidence subject to the expert examination. These answers make it possible to support these evidence items in the forensic analysis of an email and to guarantee the gathering of scientifically and technically accepted results that are valid for justice. Thus, the research question that is tried to be answered is: Is it possible to apply ontological engineering as a scientific support to design and develop a forensic tool that allows automatic answers to the evidence items subject to the expert examination in the forensic analysis of emails?

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DOI: 10.3897/jucs.97170

Authors: Layse Santos Souza, Michel S. Soares

Abstract: A smart city is an urban centre that integrates a variety of solutions to improve infrastructure performance and achieve sustainable urban development. Urban roads are a crucial infrastructure highly demanded by citizens and organisations interested in their deployment, performance, and safety. Urban traffic signal control is an important and challenging real-world problem that aims to monitor and improve traffic congestion. The deployment of traffic signals for vehicles or pedestrians at an intersection is a complex activity that changes constantly, so it is necessary to establish rules to control the flow of vehicles and pedestrians. Thus, this article describes the joint use of the SmartCitySysML, a profile proposed by the authors, with TCPN (Timed Coloured Petri Nets) to refine and formally model SysML diagrams specifying the internal behaviour, and then verify the developed model to prove behavioural properties of an urban traffic signal control system.

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DOI: 10.3897/jucs.94067

Authors: Luis P. Prieto, Gerti Pishtari, Yannis Dimitriadis, María Jesús Rodríguez-Triana, Tobias Ley, Paula Odriozola-González

Abstract: Recent advances in machine learning and natural language processing have the potential to transform human activity in many domains. The field of learning analytics has applied these techniques successfully to many areas of education but has not been able to permeate others, such as doctoral education. Indeed, doctoral education remains an under-researched area with widespread problems (high dropout rates, low mental well-being) and lacks technological support beyond very specialized tasks. The inherent uniqueness of the doctoral journey may help explain the lack of generalized solutions (technological or otherwise) to these challenges. We propose a novel approach to apply the aforementioned advances in computation to support doctoral education. Single-case learning analytics defines a process in which doctoral students, researchers, and computational elements collaborate to extract insights about a single (doctoral) learner's experience and learning process. The feasibility and added value of this approach are demonstrated using an authentic dataset collected by nine doctoral students over a period of at least two months. The insights from this exploratory proof-of-concept serve to spark a research agenda for future technological support of doctoral education, which is aligned with recent calls for more human-centred approaches to designing and implementing learning analytics technologies.

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DOI: 10.3897/jucs.79494

Authors: Robert Ehrensperger, Clemens Sauerwein, Ruth Breu

Abstract: Digital transformation impacts longstanding business models and enables enterprises to create new ones. This transformation leads to increased competition that forces enterprises to compete, not only between companies but also between the entire supply chain and business networks. The emerging concept of digital business ecosystems (DBE) allows enterprises to concentrate on network co-creation and co-evolution of bundled services and products across enterprise boundaries. This exploratory study introduces a maturity model derived from existing DBEs. Based on employing a design science methodology, we reviewed 22 scientific publications, interviewed 28 senior experts from practice and derived a maturity model from the results. We applied the maturity model through an online survey to 29 DBEs from different industry sectors and compared it with 22 maturity assessment approaches from other domains. The maturity model enables researchers to compare and assess existing DBEs and helps practitioners to identify areas for improvement in the collaboration within DBEs.

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DOI: 10.3897/jucs.79905

Authors: Fatemeh Farnaghi-Zadeh, Mohsen Rahmani, Maryam Amiri

Abstract: Feature selection plays an important role as a preprocessing step for pattern recognition and machine learning. The goal of feature selection is to determine an optimal subset of relevant features out of a large number of features. The neighborhood discrimination index (NDI) is one of the newest and the most efficient measures to determine distinguishing ability of a feature subset. NDI is computed based on a neighborhood radius (E). Due to the significant impact of E on NDI, selecting an appropriate value of E for each data set might be challenging and very time-consuming. This paper proposes a new approach based on targEt PointS To computE neIgh- borhood relatioNs (EPSTEIN). At first, all the data points are sorted in the descending order of their density. Then, the highest density data points are selected as many as the number of classes. To determine the neighborhood relations, the circles centered on the target points are drawn and the points inside or on the circles are considered to be neighbors. In the next step, the significance of each feature is computed and a greedy algorithm selects appropriate features. The performance of the proposed approach is compared to both the commonest and newest methods of feature selection. The experimental results show that EPSTEIN could select more efficient subsets of features and improve the prediction accuracy of classifiers in comparison to the other state-of-the-art methods such as Correlation-based Feature Selection (CFS), Fast Correlation-Based Filter (FCBF), Heuris- tic Algorithm Based on Neighborhood Discrimination Index (HANDI), Ranking Based Feature Inclusion for Optimal Feature Subset (KNFI), Ranking Based Feature Elimination (KNFE) and Principal Component Analysis and Information Gain (PCA-IG).

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DOI: 10.3897/jucs.80743

Authors: Mariusz Topolski, Marcin Beza

Abstract: Feature engineering is a branch of science that provides tools to support, for example, the preparation of feature spaces for a pattern recognition task. The present work focuses on the problem of feature extraction. The proposed model is based on the mechanisms of PCA principal component analysis. It fills a gap in the implementation of feature extraction by looking for spaces that best discriminate between classes. This was realized by rotating the features according to the centroids of the classes. In addition, a measure of their consistency was determined which allows precise estimation of the number of features for a particular component. Four experiments were conducted in this study. The first two were done on synthetic datasets, while the next two were conducted on ten real datasets. The synthetic data allowed to determine the characteristics depending on the percentage of informative features, the number of input features, the level of imbalance and the number of output components in the extraction task. The obtained results showed that the developed solution allows for a more precise extraction, thus increasing the quality of classification. Moreover, it was shown that the method based on class centroids allows to construct efficient ensembles of classifiers.

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DOI: 10.3897/jucs.72333

Authors: Masao Ito

Abstract: There is no standard method for describing the Operational Design Domain (ODD) in automated driving vehicles. There are many elements in the operating domain, including the external environment, and it is necessary to connect them with the internal state of the automated driving system. Its content ultimately requires the user's understanding. The description method of this ODD is summarised from the aspect of safety. Consistency with standards and guidelines will also be considered.

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DOI: 10.3897/jucs.65083

Authors: Oscar Carlos Medina, Manuel Pérez Cota, Brenda Elizabeth Meloni, Marcelo Martín Marciszack

Abstract: A pattern is a model that allows reusing a successful solution to the same problem in a different context. A pattern implementation could be the elaboration of an analysis model to incorporate good practices patterns Conceptual Modelling of Electronic Government systems. Defining a new pattern, and selecting a previously existing one from a limited set, called catalogue, are essential activities that every analysis model must solve when using patterns. The present work describes a proposal to manage a Business Patterns catalogue that can be applied to Conceptual Modelling of software products. Business Patterns allow to model and design business processes inside an organization, being it public or private. An application, called “PatCat” (Pattern Catalogue), was developed to test de proposal, using the Business Model of an Information System for a public education institution as a pilot. The introduction of patterns at the beginning of the Modelling Process allows to simplify and clarify the requirements elicitation, amongst other benefits. Thus, a specific management application for a pattern catalogue is useful to standardize and speed up this software design task.

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DOI: 10.3897/jucs.2020.064

Authors: Emilio Rodríguez-Priego, Francisco García-Izquierdo, Ángel Rubio

Abstract: Although modeling is used to address complex problems, it is difficult to study modeling itself with an easy to understand model. Many authors have proposed such a model of modeling, but a consensus on the meaning of the basic modeling concepts has yet to materialize. We claim that any proposal regarding the fundamentals of modeling should address several objectives, such as to focus on the concept of model and define what it is, how a model is created and how it relates to the entities it models or to explain the relationship between model and other basic concepts such as metamodel or (modeling-)language. In this paper, we present some of the most important elements of our proposal, named Scientific Method approach to Modeling (SMM). Our proposal uses the Scientific Method as a metaphor to explain the mechanisms of modeling, since it provides well-known mechanisms constantly utilized when developing or understanding models: validation, analysis, synthesis and analogy. Inspired by these mechanisms, our proposal addresses the notion of model by including several constructors that allow us to explain better several complex modeling mechanisms extensively discussed in the literature, such as the metamodel notion.

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DOI: 10.3897/jucs.2020.059

Authors: Ranjan Behera, Sushree Das, Santanu Rath, Sanjay Misra, Robertas Damasevicius

Abstract: Stock prediction is one of the emerging applications in the field of data science which help the companies to make better decision strategy. Machine learning models play a vital role in the field of prediction. In this paper, we have proposed various machine learning models which predicts the stock price from the real-time streaming data. Streaming data has been a potential source for real-time prediction which deals with continuous ow of data having information from various sources like social networking websites, server logs, mobile phone applications, trading oors etc. We have adopted the distributed platform, Spark to analyze the streaming data collected from two different sources as represented in two case studies in this paper. The first case study is based on stock prediction from the historical data collected from Google finance websites through NodeJs and the second one is based on the sentiment analysis of Twitter collected through Twitter API available in Stanford NLP package. Several researches have been made in developing models for stock prediction based on static data. In this work, an effort has been made to develop scalable, fault tolerant models for stock prediction from the real-time streaming data. The Proposed model is based on a distributed architecture known as Lambda architecture. The extensive comparison is made between actual and predicted output for different machine learning models. Support vector regression is found to have better accuracy as compared to other models. The historical data is considered as a ground truth data for validation.

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DOI: 10.3897/jucs.2020.031

Authors: Rastko Martać, Nikola Milivojević, Marijana Despotović-Zrakić, Zorica Bogdanović, Dusan Barać

Abstract: This paper investigates how to transform a manual monitoring system into a smart environment using IoT technologies. Large dams are of huge importance as water reservoirs and potential energy sources primarily because of their use for electric energy generation. Monitoring and predicting dams' behavior are quite challenging. Due to a variety of limitations, environmental obstacles and dam system complexity, the application of RFID, Bluetooth, and IoT technologies has proven to be an adequate, affordable and reliable dam safety solution. This paper introduces a comprehensive model of dam safety management and monitoring based on pervasive technologies. The model described in this work has been applied within the large dam "Iron Gate 1", on the river Danube in the Republic of Serbia. The results show that the use of new technologies in the dam monitoring process can reduce human error and improve overall process.

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DOI: 10.3897/jucs.2020.023

Authors: Milan Sečujski, Darko Pekar, Siniša Suzić, Anton Smirnov, Tijana Nosek

Abstract: The paper presents a novel architecture and method for training neural networks to produce synthesized speech in a particular voice and speaking style, based on a small quantity of target speaker/style training data. The method is based on neural network embedding, i.e. mapping of discrete variables into continuous vectors in a low-dimensional space, which has been shown to be a very successful universal deep learning technique. In this particular case, different speaker/style combinations are mapped into different points in a low-dimensional space, which enables the network to capture the similarities and differences between speakers and speaking styles more efficiently. The initial model from which speaker/style adaptation was carried out was a multi-speaker/multi-style model based on 8.5 hours of American English speech data which corresponds to 16 different speaker/style combinations. The results of the experiments show that both versions of the obtained system, one using 10 minutes and the other as little as 30 seconds of target data, outperform the state of the art in parametric speaker/style-dependent speech synthesis. This opens a wide range of application of speaker/style dependent speech synthesis based on small quantities of training data, in domains ranging from customer interaction in call centers to robot-assisted medical therapy.

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DOI: 10.3897/jucs.2020.021

Authors: Thi Ngoc Trang Tran, Muesluem Atas, Man Le, Ralph Samer, Martin Stettinger

Abstract: Explanations are integrated into recommender systems to give users an insight into the recommendation generation process. Compared to single-user recommender systems, explanations in group recommender systems have further goals. Examples thereof are fairness, which helps to take into account as much as possible group members' preferences and consensus, which persuades group members to agree on a decision. In this paper, we proposed different types of explanations and found the most effective ones in terms of increasing the fairness perception, consensus perception and satisfaction of group members with regard to group recommendations. We conducted a user study to evaluate the proposed explanations. The results show that explanations which consider the preferences of all or the majority of group members achieve the best results in terms of the mentioned dimensions. Besides, we discovered positive correlations among these aspects. In the context of repeated decisions, group members' satisfaction from previous decisions are helpful to improve the fairness perception of users concerning group recommendations and speed up the group decision-making process. Furthermore, we found out that gender diversity does influence the perception of users regarding the mentioned dimensions of the explanations. Although the proposed explanations were analyzed in group decision scenarios for non-configurable (no-attribute) items, there exist potential possibilities to apply them to explanations for configurable items.

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DOI: 10.3897/jucs.2020.020

Authors: Jeppe Rasmussen, Lars Hvam, Katrin Kristjansdottir, Niels Mortensen

Abstract: Product configuration systems (PCSs) are increasingly being used in various industries to manage product knowledge and create the required specifications of customized products. Companies applying PCS face significant challenges in modelling, structuring and documenting the systems. Some of the main challenges related to PCSs are formalising product knowledge conceptually and structuring the product features. The modelling techniques predominantly used to visualise and structure PCSs are the Unified Modelling Language (UML) notations, Generic Bill of Materials (GBOM) and Product Variant Master (PVM), associated with class collaboration cards (CRC-cards). These methods are used to both analyse and model the products and create a basis for implementation to a PCS by using an object-oriented approach. However, the modelling techniques do not consider that most commercial PCSs are not fully object-oriented, but rather, they are expert systems with an inference engine and a knowledge base; therefore, the constructed product models require modifications before implementation in the configuration software. The consequences are that what is supposedly a feasible structure of the product model is not always appropriate for the implementation in standard PCS software. To address this challenge, this paper investigates the best practice in modelling and implementation techniques for PCSs in standard software and alternative structuring methods used in object-oriented software design. The paper proposes a method for a modular design of a PCS in not fully object-oriented standard PCS software using design patterns. The proposed method was tested in a case company that suffered from a poorly structured product model in a not fully object-oriented PCS. The results show that its maintainability can be improved by using design patterns in combination with an agile documentation approach.

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DOI: 10.3897/jucs.2020.007

Authors: Anastasija Nikiforova, Janis Bicevskis, Zane Bicevska, Ivo Oditis

Abstract: The paper proposes a new data object-driven approach to data quality evaluation. It consists of three main components: (1) a data object, (2) data quality requirements, and (3) data quality evaluation process. As data quality is of relative nature, the data object and quality requirements are (a) use-case dependent and (b) defined by the user in accordance with his needs. All three components of the presented data quality model are described using graphical Domain Specific Languages (DSLs). In accordance with Model-Driven Architecture (MDA), the data quality model is built in two steps: (1) creating a platform-independent model (PIM), and (2) converting the created PIM into a platform-specific model (PSM). The PIM comprises informal specifications of data quality. The PSM describes the implementation of a data quality model, thus making it executable, enabling data object scanning and detecting data quality defects and anomalies. The proposed approach was applied to open data sets, analysing their quality. At least 3 advantages were highlighted: (1) a graphical data quality model allows the definition of data quality by non-IT and non-data quality experts as the presented diagrams are easy to read, create and modify, (2) the data quality model allows an analysis of "third-party" data without deeper knowledge on how the data were accrued and processed, (3) the quality of the data can be described at least at two levels of abstraction - informally using natural language or formally by including executable artefacts such as SQL statements.

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DOI: 10.3217/jucs-025-13-1717

Authors: Andreas Hinderks, Dominique Winter, Martin Schrepp, Jörg Thomaschewski

Abstract: To be successful, interactive products need to fulfil user expectations and create a positive user experience (UX). An established method to measure UX involves questionnaires. What we aim in this paper is to present a list of user experience and United States of Americability questionnaires and its applicability for different digital products. A total of 13 questionnaires on United States of Americability and UX were analysed for this paper, and 25 factors were extracted from those questionnaires. A study was conducted based on this collection of factors with N=61 students. The study investigated the perceived importance of United States of Americability and UX factors for seven digital products. The goal was to have a collection of United States of Americability and UX factors that could be combined for suitable products evaluation. The results of the study revealed that no questionnaire covered all the factors perceived important by the participants.

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DOI: 10.3217/jucs-025-12-1625

Authors: Carlos De Carvalho, Pedro Cano, José Roa, Anna Wanka, Franz Kolland

Abstract: Being able to effectively use online tools has become a fundamental competence in our Society. Therefore, it is important to tackle the age digital divide as there is a rapidly growing number of elderly people. Like everyone else, older adults (senior citizens or the silver generation) must be equipped with the necessary skills to be able to be connected and integrated in the online world to prevent their social isolation and to foster their inclusion. As a contribution to that effort, a European-wide digital literacy development initiative for senior citizens was setup and this article presents the analysis of the achieved results which shows a very positive perception of the seniors on the developed digital abilities.

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DOI: 10.3217/jucs-025-09-1199

Authors: François Bouchaud, Gilles Grimaud, Thomas Vantroys, Pierrick Buret

Abstract: The Internet of Things (IoT) is everywhere around us. Smart communicating objects are offering the digitalization of lives. They create new opportunities within criminal investigations. In recent years, the scientific community sought to develop a common digital framework and methodology adapted to IoT-based infrastructure. However, the difficulty in exploiting the IoT lies in the heterogeneous nature of the devices, the lack of standards and the complex architecture. Although digital forensics are considered and adopted in IoT investigations, this work only focuses on the collection. The identification phase is quite unexplored. It addresses the challenges of locating hidden devices and finding the best evidence to be collected. The matter of facts is the traditional method of digital forensics does not fully fit the IoT environment. Furthermore, the investigator can no longer consider a connected object as a single device, but as an interconnected whole one, anchored in a cross-disciplinary environment. This paper presents the methodology for identifying and classifying connected objects in search of the best evidence to be collected. It offers techniques for detecting and locating the appropriate equipment. Based on frequency mapping and interactions, it transfers the concept of "fingerprinting" into the field of crime scene. It focuses on the technical and data criteria to successfully select the relevant IoT devices. It gives a general classiffication as well as the limits of such an approach. It shows the collection of digital evidence by focusing on pertinent information from the Internet of Things.

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DOI: 10.3217/jucs-025-08-0967

Authors: Benjamin Weyers, Ekaterina Auer, Wolfram Luther

Abstract: We suggest to widen the focus of the scientific computations community from an isolated consideration of reliable numerical algorithms using standardized arithmetic to a broad user-centered system modeling and simulation approach relying on an appropriate verification and validation (V&V) design. Most V&V works rarely consider human-related issues specifically. However, modern applications generate and employ huge amounts of heterogeneous data and usually exhibit high complexity - challenges that are best tackled by augmenting human reasoning with automated techniques. That is, novel visual and collaborative approaches are needed to interpret the results, which has to be accounted for in the general V&V procedure. This should include an assessment of (meta-) data and code/outcome quality, selection of methods to propagate and bound uncertainty and, lastly, formally rigorous validation efforts. We present an approach to reliable visual analytics (i.e., analytics subjected to this V&V assessment), which can in turn contribute to the overall V&V procedure after that. Two use cases illustrate the potential of the introduced framework for reliable visual analytics.

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DOI: 10.3217/jucs-025-08-0946

Authors: Jonathan Frez, Nelson Baloian, José Pino, Gustavo Zurita, Franco Basso

Abstract: Planning efficient public transport is a key issue in modern cities. When planning a route for a bus or a line for a tram or subway, it is necessary to consider people's demand for this service. In this work we present a method to use existing crowdsourced data (like Waze and OpenStreetMap) and cloud services (like Google Maps) to support a transportation network decision making process. The method is based on the Dempster-Shafer Theory to model transportation demand. It uses data from Waze to provide a congestion probability and data from OpenStreetMap to provide information about location of facilities such as shops, in order to predict where people may need to start or end their trips using public transportation vehicles. The paper also presents an example using this method with real data. The example shows an analysis of the current availability of public transportation stops in order to discover its weak points.

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DOI: 10.3217/jucs-024-07-0975

Authors: Yves Wautelet, Manuel Kolp, Loris Penserini

Abstract: The increased symbiotic relationships between society and Information and Communication Technology (ICT) pave the ways for a substantial alignment and rethinking of current software development methodologies. This paper presents the use and validation of a software analysis and project management (PM) framework for iterative software development within the Tropos method. This methodology is servicedriven, its requirements models are founded on social-based modeling elements. The PM framework includes risk and quality management; it has been applied on multiple case studies and this paper presents a full experience report. The proposed methodology is aimed to provide a reference for practitioners willing to develop iteratively using Tropos.

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DOI: 10.3217/jucs-024-04-0392

Authors: Hasiba Attia, Laid Kahloul, Saber Benharzallah

Abstract: New technologies as cloud computing and internet of things (IoT) has expanded the range of multimodal applications. This expansion, in several computing and heterogeneous environments, makes access control an important issue in multimodal applications. Indeed, a variety of access control models have been developed to address different aspects of security problems. The two most popular basic models are: Role Based Access Control (RBAC) and Attribute Based Access Control (ABAC). The both models RBAC and ABAC have their specific features and they can complement each other. For that, providing a hybrid model which considers both concepts "roles" as well as "attributes" has become an important research topic. This paper proposes a new access control model based principally on roles, attributes, access modes and the type of resources. An empirical method is applied to compare the new proposed model versus three existing models: RBAC, ABAC, and the hybrid model Attribute Enhanced RBAC (AERBAC). The results of the empirical method demonstrate that the new proposed model acquires the advantages of the two models RBAC and ABAC and avoids their limitations. In fact, the new proposed model reduces the complexity of security policies and allows expressing the fine granularity of systems without any explosion in the number of roles or rules in the security policy.

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DOI: 10.3217/jucs-024-03-0249

Authors: Hoon Ko, Seogchan Hwang, Libor Mesicek, Jongsun Choi, Junho Choi, Pankoo Kim

Abstract: This paper is to study how to provide smart services by analyzing each service history based on Cloud computing in smart cities. Normally, users use each smart device to receive their services while they stay in a place. In case they move and visit to other place, the system prepares the service based on their services history. At that time, although the users had visited and had services in past, this visiting may ask other services. Then the existing system usually generates new service, and next it provides the service to the user. However, this method is inefficient, because the system has to accept the number of process whenever all users request the service. In this paper, it suggests the smart service model that it keeps users' services history, which had used them while the user stays to a place. The system catches the user's visiting with the user's contexts in the smart device. The model considers their plan/purpose based on old services, and it decides if they modifies them by editing extra services. It calls the system optimization and the suggesting method shows better efficiency after experimenting.

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DOI: 10.3217/jucs-024-02-0192

Authors: William Guest, Fridolin Wild, Alla Vovk, Paul Lefrere, Roland Klemke, Mikhail Fominykh, Timo Kuula

Abstract: Leveraging Augmented Reality and wearable technology for knowledge-intensive training is thought to offer huge potential for improving human performance. The recent introduction of the technology means that much of this potential is untapped, though efforts are needed to understand what makes it useful, entertaining, and easy-to-use. The research presented in this article investigates the implementation of a combined hardware and software application in three use-cases: aviation, medical and space. Following the validation of metrics for a questionnaire, data was collected from 142 participants, and a structural equation model, based on UTAUT2, was proposed in order to interpret the data. Following model improvement, two constructs show significant factor loading and latent variable correlation, Interoperability and Augmented Reality / Wearable Technology Fit. Model optimisation was conducted, and a variety of goodness-of-fit indices are reported. The two additional constructs are found to be covariant and impact the UTAUT2 variables performance expectancy, effort expectancy and facilitating conditions, in some cases explaining more than 85% of the variance in those constructs (p < 0.001). A root mean square error of approximation of 0.047 after a 1000-fold Monte Carlo cross-validation indicates a good fit between the model and the data. In all other fit indices, a moderate power has been observed.

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DOI: 10.3217/jucs-024-02-0171

Authors: Samah Felemban, Michael Gardner, Victor Callaghan, Anasol Pena-Rios

Abstract: 3-D virtual worlds and other immersive environments offer features that other learning systems cannot easily replicate. As such, they have the potential to revolutionise the way in which people learn. They are well suited to visualise 3-D objects and their relations to explain complex phenomena. In addition, they enable practical experiments to be performed that are difficult to conduct in the real world. They can also help to facilitate collaborative learning in real-time and enable students to become fully engaged in what they are doing. However, these environments require further exploration to improve their learning affordances. For instance, assessing students' performance and collecting learning evidence is still in its early stages. This paper is primarily devoted to furthering our understanding of observation and assessment. In so doing, a virtual observation model has been developed to effectively map classroom-based observations with how people can be evaluated in virtual 3-D environments. The observation model has been applied to a multi-user virtual environment (MUVE) and examples that illustrate its potential effectiveness are provided. In essence, our research aims to support and enhance the learning experience by demonstrating the advantages of 3-D virtual worlds as a means for advancing learning processes.

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DOI: 10.3217/jucs-024-02-0072

Authors: Max North, Sarah North

Abstract: The primary objective of this concise collection is to explore the sense of presence that participants experience in Virtual Reality Therapy experiments. In this article, sense of presence is briefly defined, followed by a discussion of factors effecting sense of presence, continuing with methods to measure sense of presence and assertions concerning virtual presence, and finally, conclusions and discussions are presented.

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DOI: 10.3217/jucs-023-07-0636

Authors: Gaoshan Deng, Quanxi Feng, Pan Zheng, Tao Song

Abstract: Heterogeneous computing systems (HCSs) use many heterogeneous processors or cores to perform particular tasks. To address the requirement of green IT, several power management techniques have been developed to reduce the energy consumption of these systems. Dynamic voltage scaling, which dynamically changes the supply voltage of processors during the execution of an application, is widely used. However, reducing supply voltage decreases computation speed. Therefore, system makespan and energy consumption need to be considered at the same time. We propose a multi-objective scheduling algorithm based on decomposition for scheduling of the system workflow. Through experiments, we examine the performances of several algorithms, including the proposed one, in different benchmarks and real-world applications. Results show that our algorithm demonstrates better performance than other state-of-art evolutionary algorithms under various conditions involving the use of different crossover and mutation operators.

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DOI: 10.3217/jucs-022-06-0856

Authors: Piotr Jędrzejowicz, Ewa Ratajczak-Ropel

Abstract: In this paper the dynamic interaction strategy based on the Population Learning Algorithm (PLA) for the A-Team solving the Resource-Constrained Project Scheduling Problem (RCPSP) is proposed and experimentally validated. The RCPSP belongs to the NP-hard problem class. To solve this problem a team of asynchronous agents (A-Team) has been implemented using multiagent system. An A-Team is the set of objects including multiple agents and the common memory which through interactions produce solutions of optimization problems. These interactions are usually managed by some static strategy. In this paper the dynamic learning strategy based on PLA is suggested. The proposed strategy supervises interactions between optimization agents and the common memory. To validate the proposed approach computational experiment has been carried out.

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DOI: 10.3217/jucs-022-03-0394

Authors: Vanja Smailovic, Vedran Podobnik

Abstract: In today's networked society where everybody and everything becomes inter-connected, it is very important to be able to identify key actors and key relationships in such a complex multi-layered eco-system. This paper focuses on the specific research challenge of identifying the most influential actors in a social network built through combining relationships among same actors in two different domains - communication domain (proxied through real-world mobile phone communication data) and social networking service domain (proxied through real-world Facebook data). A practical aspect of the paper is evaluated through the SmartSocial Platform, which uses methodology and implements algorithms that enable: i) joining multiple relations among actors across different social networks into the single unified social network; as well as ii) mining created unified social network for identification of most influential actors. Evaluation of the proposed approach is based on the social experiment with 465 users. Experiment results underline two important paper contributions: i) posting frequency sensitivity analysis shows a significant effect of posting frequency on social influence scores; and ii) interdependency analysis shows a synergic effect of combining data from communication and social networking service domains when it comes to calculating influence scores.

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DOI: 10.3217/jucs-022-03-0360

Authors: Gui-Xun Luo, Yun Liu, Zhi-Yuan Zhang

Abstract: In this paper, based on abundant data from Sina Weibo, we perform a comprehensive and in-depth empirical analysis of repostings and draw some conclusions. First, in regards to quantity, reposting takes up a large proportion of daily microblog activity. Second, the depth of repostings follows an exponential distribution and the first three orders of repostings hold 99 percent of the total amount of reposting, which provides an important foundation for solving the question of Influence Maximization. Third, the time interval for repostings also obeys exponential distribution. Therefore, we have built a dynamic information propagation model in terms of conclusions drawn from Weibo data and the Continuous-Time Markov Process. Due to the basis of the temporal network, our proposed model can change with the time and structure of a network, thus giving it good adaptability and predictability as compared to the traditional information diffusion model. From the final simulation results, our proposed model achieves a good predictive effect.

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DOI: 10.3217/jucs-021-11-1508

Authors: Marco Spruit, Catalina Sacu

Abstract: Data Warehouses and Business Intelligence have become popular fields of research in recent years. Unfortunately, in daily practice many Data Warehouse and Business Intelligence solutions still fail to help organizations make better decisions and increase their profitability, due to intransparent complexities and project interdependencies. In addition, emerging application domains such as Mobile Learning & Analytics heavily depend on a well-structured data foundation with a longitudinally prepared architecture. Therefore, this research presents the Data Warehouse Capability Maturity Model (DWCMM) which encompasses both technical and organizational aspects involved in developing a Data Warehouse environment. The DWCMM can be used to help organizations assess their current Data Warehouse solution and provide them with guidelines for future improvements. The DWCMM consists of a maturity matrix and a maturity assessment questionnaire with 60 questions. The DWCMM has been evaluated empirically through expert interviews and case studies. We conclude that the DWCMM can be successfully applied in practice and that organizations can intelligibly utilize the DWCMM as a quickscan instrument to jumpstart their Data Warehouse and Business Intelligence improvement processes.

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DOI: 10.3217/jucs-021-06-0871

Authors: Ngoc Luong, Tuong Nguyen, Dosam Hwang, Chang Lee, Jai Jung

Abstract: As communities of researchers continue to become quite large and to grow incessantly, collaboration among researchers can be conducive to greater research productivity. Nevertheless, it is difficult for a researcher to find suitable collaborators from all researchers around the world. In this paper, we have used bibliographic DBLP data to extract information of a researcher and to discover the relationship between the co-authors and between authors and conferences. We evaluated some of the similarity measures and developed an innovative random walk model to find potential co-authors for a given researcher. These measures were then used to design a best model to recommend co-authors. We have also applied an HITS algorithm and proposed a ranking algorithm to rank researchers and conferences with the intent of recommending authors or conferences.

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DOI: 10.3217/jucs-021-06-0796

Authors: Quang Tran, Jai Jung

Abstract: Discovering content and stories in movies is one of the most important concepts in research studies. To consider how to efficiently determine the relationships between characters, we focus on the appearance of each character during movie play and analyze the characters' relationships to build a CoCharNet, a social network, to determine characters' relationships in a movie. In this paper, we propose an innovative method which extracts and analyzes characters' relationships based on social network measurement and evaluation.

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DOI: 10.3217/jucs-021-01-0048

Authors: Alan Dix, Justin Leavesley

Abstract: If learning analytics are to directly benefit students' learning rather than simply inform broad policy decisions, they must be used by academics in the midst of busy and fragmented lives. This paper takes an ecological or action-oriented perspective of the use of learning analytics in higher education, drawing on research sources in psychology, human-computer interaction and visual analytics. We unpack the circumstances during the learning interactions of academics with course materials and students where analytics could trigger or influence action. This leads to a framework based around different academic timescales, and the strategies for synchronising the recognition of need with the potential for execution of teaching and learning interventions.

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DOI: 10.3217/jucs-020-15-2054

Authors: Francesco Colace, Massimo Santo, Luca Greco

Abstract: E-Learning is offering new approaches and opportunities in the field of education above all in the sector of the virtual laboratories. The opportunity to interact with the real instruments that are in a lab represents an effective way for the implementation of a teaching approach oriented to a problem solving strategy. The wide diffusion of mobile devices (smartphones and tablets) makes this approach more effective and appealing for the students. In this paper we introduce Jini Technologies to design and implement a distributed architecture for a mobile virtual lab for supporting the activities of an Electronic Measurement Course. The aim of this environment is offering to the students the opportunity to experiment a real interaction with the laboratory's instruments everywhere and every time by the use of mobile devices. A prototype of the architecture and its services will be discussed and an evaluation campaign will be showed.

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DOI: 10.3217/jucs-020-13-1791

Authors: Cheng Zheng, Weiming Shen, Hamada Ghenniwa

Abstract: Service discovery and integration is an important research area with efforts invested to explore the potential advantages of collaborative computing in general and service-oriented computing in particular. However, current technologies still limit their application within the reach of enterprise systems or privately available services. Intents is an emerging and innovative technique aimed to discover and integrate publically available services. In Intents, intent message resolving is a critical step which is deemed to decide the quality of the whole system. However, existing schemes applied in intent resolving adopt the exact-matching strategy which may rule out services desired by the user. This paper brings in information retrieval techniques and applies them to intent resolving. We take an empirical approach through extensive experiments and analyses on a real dataset to obtain guiding principles. Based on the resulting principles, an adaptive intent resolving scheme is designed. Afterwards, we integrate the scheme into the Intents user agent developed in a previous project.

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DOI: 10.3217/jucs-020-14-1964

Authors: Tapio Soikkeli, Juuso Karikoski, Heikki Hämmäinen

Abstract: Utilizing rich end user context information is viewed as one of the necessary approaches in developing more personalized mobile services and user experiences. The practical impact of end user context research and new opportunities in the field provided by emerging data collection methods such as handset-based measurements (i.e., collecting usage data directly from the end users' devices) have inspired new highly interesting large scale empirical context studies, but also brought quite diverse usage of the term context itself. Proper discussion and usage of context requires an unambiguous statement of how the term is understood in the particular case. On one hand the term should be positioned with the existing and commonly understood general definitions, but on the other hand it should also be acknowledged that especially an empirical research paper, or a context-aware service, can grasp only some specific aspects or elements of context. This paper proposes a context classification framework that aims to clarify the use of the term context in handset-based related end user studies. The framework is partly based on the experimental experience accumulated in our own handset panel studies. While helping researchers to plan context data acquisition and communicate and position the end user context elements used, the framework helps other stakeholders, such as application developers and service providers, to identify and utilize research and data most relevant for their particular needs. The paper also demonstrates the expressivity of the framework by examples.

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DOI: 10.3217/jucs-020-09-1284

Authors: Narayanan Kulathuramaiyer, Hermann Maurer, Rizwan Mehmood

Abstract: When we look up information in the WWW we hope to find information that is correct, fitting in quantity for our purposes and written at a level that we can understand. Unfortunately, very often one of the above criteria will not be met. A young person looking for information on some aspect of physics may well be frustrated when finding a complex formula whose understanding requires higher mathematics. In other cases, information may be much too voluminous or too short. This seems to indicate that what we need is presentation of material at various levels of detail and complexity. But most important of all, and this is what we are going to discuss in this paper is: how do we know that what we read is actually true? We will analyse this problem in the introductory section. We will show that it is impossible to expect "too much". We will argue that some improvements can be made, particularly if the domain is restricted. We will then examine certain types of geographical information. Detailed research shows that some quantitative measurements like the area of a country or the highest mountains of a country, even if different sources disagree, can be verified by explaining why the discrepancies occur and by trusting numbers if they are identical in very different databases.

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DOI: 10.3217/jucs-020-06-0826

Authors: Maral Mayeh, Thurasamy Ramayah, Simona Popa

Abstract: The purpose of this study is to model the relationship between absorptive capacity and intention to use in the Enterprise Resource Planning (ERP) environment in Iran. This research is a correlation study where a field survey was employed for data collection. The unit of analysis is Iranian individuals who are ERP user in organizations using ERP systems. The questionnaires were sent to the selected organizations. Using a structural equation modeling analysis we tested the hypothesized relationship using AMOS version 16.0. The results indicate that all three absorptive capacity measures to be good predictors of intention to use. Absorptive capacity for applying was the strongest predictor followed by absorptive capacity for understanding and absorptive capacity for assimilating. When implementing complex information systems, managers must also look at the absorptive capacity of the users in order to successful implementation of the system and to ensure continued usage. Previous researchers have not looked at the role of absorptive capacity in system usage at the same rate as those related to technology acceptance research which only focuses on the ease of use and usefulness. Thus this research adds on to the existing literature where future researchers may want to expand on the factors that may influence absorptive capacity for further policy implications.

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DOI: 10.3217/jucs-019-18-2656

Authors: María González-García, Lourdes Moreno, Paloma Martínez, Raúl Miñon, Julio Abascal

Abstract: The spectacular rise of multimedia Web content, especially video and audio content, makes addressing its accessibility a matter of urgency. All the regulations recognize that this type of content must be accessible to everyone, with or without a disability. To address this issue, this article presents a Model-Based Graphical Editor to design Accessible Media Players. This tool has been created in order to provide support to designers with little background in accessibility. To accomplish this work, a review of Accessibility Standards Regulation has been carried out, a set of accessibility requirements for accessible media players is proposed and a modelling of these requirements has been made.

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DOI: 10.3217/jucs-019-17-2598

Authors: Juan Mateu, Xavier Alamán

Abstract: Nowadays, one of the hot issues in the agenda is, undoubtedly, the concept of Sustainable Computing. There are several technologies in the intersection of Sustainable Computing and Ambient Intelligence. Among them we may mention "Human-Centric Interfaces for Ambient Intelligence" and "Collaborative Smart Objects" technologies. In this paper we present our efforts in developing these technologies for "Mixed Reality", a paradigm where Virtual Reality and Ambient Intelligence meet. Cubica is a mixed reality educational application that integrates virtual worlds with tangible interfaces. The application is focused on teaching computer science, in particular "sorting algorithms". The tangible interface is used to simplify the abstract concept of array, while the virtual world is used for delivering explanations. This educational application has been tested with students at different educational levels in secondary education, having obtained promising results in terms of increased motivation for learning and better understanding of abstract concepts.

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DOI: 10.3217/jucs-019-17-2577

Authors: George Okeyo, Liming Chen, Hui Wang

Abstract: Activity recognition enables ambient assisted living applications to provide activity-aware services to users in smart homes. Despite significant progress being made in activity recognition research, the focus has been on simple activity recognition leaving composite activity recognition an open problem. For instance, knowledge-driven activity recognition has recently attracted increasing attention but mainly focused on simple activities. This paper extends previous work by introducing a knowledge-driven approach to recognition of composite activities such as interleaved and concurrent activities. The approach combines the recognition of single and composite activities into a unified framework. To support composite activity modelling, it combines ontological and temporal knowledge modelling formalisms. In addition, it exploits ontological reasoning for simple activity recognition and qualitative temporal inference to support composite activity recognition. The approach is organized as a multi-agent system to enable multiple activities to be simultaneously monitored and tracked. The presented approach has been implemented in a prototype system and evaluated in a number of experiments. The experimental results have shown that average recognition accuracy for composite activities is 88.26%.

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DOI: 10.3217/jucs-019-17-2543

Authors: Jaime Caffarel, Song Jie, Jorge Olloqui, Rocío Martínez, Asunción Santamaría

Abstract: This paper presents an Ontology-Based multi-technology platform designed to avoid some issues of Building Automation Systems. The platform allows the integration of several building automation protocols, eases the development and implementation of different kinds of services and allows sharing information related to the infrastructure and facilities within a building. The system has been implemented and tested in the Energy Efficiency Research Facility at CeDInt-UPM.

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DOI: 10.3217/jucs-019-17-2526

Authors: Constantin Taivan, Rui José, Bruno Silva, Ivan Elhart, Jorge Cardoso

Abstract: Urban spaces are increasingly embedded with various types of public digital displays. Many of these displays can be subject to multi-user interactions and support a broad range of applications. A fundamental implication emerging from the interactive nature of those applications is that users should have access to appropriate selection and control techniques that would allow them to drive the way applications are shown and used in the respective environment. Such techniques should enable each user to reason and express intentions about the system behavior, while also dealing with concurrent requests from multiple users in a way that is fair and clear. In this study, we aim to inform the definition of novel techniques for application selection and control in pervasive display environments that can address the above challenges. Drawing inspiration from traditional GUI interaction concepts we developed and deployed a public display system that supports multiple applications and is able to receive explicit content presentation requests from multiple viewers. Based on the experiment observations and interviews with the participants, we reached a set of design considerations for future pervasive displays environments that are open to third party applications providers and allow the audience to influence content presentation.

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DOI: 10.3217/jucs-019-17-2503

Authors: Ana Bernardos, Luca Bergesio, Josue Iglesias, José Casar

Abstract: In this paper, we exploit the capabilities of mobile devices as instruments to facilitate interaction in spaces populated with smart objects. We do this through MECCANO, a framework that supports an interaction method for a user to perform physical discovery and versatile configuration of behaviors involving a network of smart objects. Additionally, MECCANO guides the developer to easily integrate new augmented objects in the smart ecosystem. Behaviors are rule-based micro-services composed by a combination of events, conditions and actions that one or more smart objects can trigger, detect or perform. Each object owns and publishes its capabilities in a software module; this module becomes available when a user physically lies in the area of influence of the smart object. The capabilities provided by a specific object can be merged with those in other objects (including those in the user's mobile device itself) to configure a behavior involving several objects, adapted to the user's needs. On operation, the behavior is run within the mobile device, serving the device as orchestrator of the involved objects. The framework also facilitates sharing micro-services in such a way that users can act as prosumers by generating their self-made behaviors. New behaviors are associated to the classes of objects that are needed to execute them, becoming ready for other users to download. The proposed interaction method and its tools are demonstrated both from the developer's and the end-user's points of view, through practical implementations.

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DOI: 10.3217/jucs-019-16-2420

Authors: Bo Liu, Baokang Zhao, Bo Liu, Chunqing Wu

Abstract: Quantum Key Distribution (QKD) technology, based on the laws of physics, can create unconditional security keys between communication parties. In recent years, researchers draw more and more attention to the QKD technology. Privacy amplification is a very significant procedure in QKD system. In this paper, we propose the real-time privacy amplification (RTPA) scheme which converts the weak secret string to a uniform key that is fully secret from Eve. Our detailed proofs show the security of our RTPA scheme. In order to prevent the potential man-in-middle attacks, we employ an authentication procedure to RTPA scheme (ARTPA) with the "-XOR almost universal hash functions. We implement our ARTPA scheme based on CLIP system, which is connected to the quantum communication system. Considering the privacy amplification and authentication overhead and the finite size effect on the security of final keys, we set the secret key length be 256k before privacy amplification and the authentication tag length be 60. Our experimental results show the efficiency of the proposed ARTPA scheme.

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DOI: 10.3217/jucs-019-15-2320

Authors: Karol Rástočný, Michal Tvarožek, Maria Bielikova

Abstract: Information seeking on the Web has become day-to-day routine for more than two billion human beings most of who use traditional keyword-based search engines. Developers of these search engines stress personalization, prediction of users' next actions and mistake correction. But they are still struggling with results presentation and support for users, who make atypical queries or who do not exactly know what they are looking for. We address these issues via a novel approach for exploring web repositories, which naturally combines user search activities - look up, learning and investigation. We achieve this via view-based navigation in hierarchical clusters and two-dimensional graphs of search results.

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DOI: 10.3217/jucs-019-15-2292

Authors: Javier Fernández, Juan Augusto, Giuseppe Trombino, Ralf Seepold, Natividad Madrid

Abstract: Traders are required to work in the financial market with highly complex information and to perform efficiently under high levels of psychological pressure. Multiple disciplines, from programs with artificial intelligence to complex mathematical functions, are used to help traders in their effort to maximize profits. However, an essential problem not yet considered in this rapidly evolving environment is that traders are not supported to adequately manage how stress influences their decisions. This paper takes into consideration the negative influences of stress on individuals and proposes a system designed to support traders by providing them with information that can reduce the likelihood of poor decision-making. The system has been designed considering both technical and physiological aspects to make information available in a suitable way. Biometric sensors are used to collect data associated with stress, a software platform then analyses this information and displays it to the trader. The resulting system is capable of making individual traders, as well as teams of traders, self-aware of their levels of stress. The system has been tested in real environments and the results provide evidence that self-aware traders benefit from the system by reducing risky decision-making.

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DOI: 10.3217/jucs-019-15-2266

Authors: Javier Marco, Sandra Baldassarri, Eva Cerezo

Abstract: In this paper, the design process of a tangible game for a tabletop device (NIKVision) is presented. NIKVision is intended to give leisure and fun while reinforcing physical manipulation and co-located gaming for 3-6 year old children. Interaction is provided by the handling of conventional toys and computer augmentation on a table surface. The presence of an additional vertical monitor that complements table surface output is a distinguishing feature of NIKVision. By following a engineering design lifecycle, the paper describes the complete process of designing a Farm Game for the tabletop. Children have been involved, for the very starting point, through continuous test sessions in schools and nurseries. The data recovered from these sessions have been essential, not only to detect problems, but to take the more adequate design decisions. Different children-centred design methods have been used, depending on the question to be evaluated or designed, ranging from observation notes to Wizard of Oz, or video-analysis. The paper exposes the results of a final summative evaluation that summarizes the performance of the game in relation to Usability, User Experience and physical and co-located gaming. The experience obtained by the authors from this process has crystalized in a set of reflections about the feasibility of designing with very young children and about the value of the data obtained from them.

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DOI: 10.3217/jucs-019-13-2013

Authors: Antonio Cabanas-Abascal, Eduardo García-Machicado, Lisardo Prieto-González, Antonio Seco

Abstract: Nowadays, one of the most relevant features provided by in almost every web site is a recommender system. However, they are usually focused on the common characteristics of several items which are shared among the users without taking into account that there are other very important features, such as geo-position. To face this lack of such relevant factors, authors propose the usage of a useful system that will aid in tasks related to pattern detection and fast adaptability to changes: Artificial Immune System. A combination of both systems and the addition of a geographic component will provide a new solution to this problem, which will solve as well these issues as other ones like comparison tasks in big data.

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DOI: 10.3217/jucs-019-13-1963

Authors: Cheng Xie, Hongming Cai, Lihong Jiang

Abstract: Resource-oriented Services recently become an enabling technology to integrate and configure information from different heterogeneous systems so as to meet ever-changing environment which not only need the concepts for entities but also require the semantics for operations. By the aim of combining structural and operational semantics agilely, a Semantic Resource Service Model (SRSM) is proposed. Firstly, SRSM describes Entity-Oriented and Transition-Oriented Resource by semantic meta-model which contains data structures and operation semantics. Secondly, by describing structural semantics for Entity-Oriented Resource, heterogonous inputs/outputs of a service can be automatically matched. Thirdly, by describing operational semantics for Transition-Oriented Resource, the service composition sequence can be inferred after ontology reasoning. Then, both Entity-Oriented and Transition-Oriented Resources are encapsulated into composited RESTful service. At last, a case study and several comparisons are applied in a prototype system. The result shows that the proposed approach provides a flexible way for resource-oriented service composition.

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DOI: 10.3217/jucs-019-12-1854

Authors: Leonardo Lezcano, Brigitte Jörg, Brian Lowe, Jon Corson-Rikert

Abstract: Institutional repositories (IR) and Current Research Information Systems (CRIS) store and manage information on the context in which research activity takes place. Several models, standards and ontologies have been proposed to date as solutions to provide coherent semantic descriptions of research information. These present a large degree of overlap but also present very different approaches to modelling. This paper introduces a contrast of two of the more widespread models, the VIVO ontology and the CERIF standards, and provides guidance for mapping them in a way that enables clients to integrate data coming from heterogeneous sources. The majority of mapping challenges have risen from the representation of VIVO sub-hierarchies in CERIF as well as from the representation of CERIF attributes in VIVO. In addition, the paper illustrates features for linking data across the Web, for querying of geographically distributed data stores and for aggregating data described using different data models in a common store. These features are supported by semantic web technologies including RDF, OWL and SWRL.

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DOI: 10.3217/jucs-019-12-1792

Authors: Pedro Villanueva, Ricardo Tesoriero, José A. Gallud Lázaro, Abdulrahman Altalhi

Abstract: The pervasiveness of the Web, and the emergence of new technologies such as the RFID, allow users to interact with the physical environment. This fact has caused the conception of new types of applications, for instance, the Web applications based on RFID panels that allow users to retrieve and store resources from and to the Web through RFID panels. The development of these applications is defined by three main concepts: the Tool that performs domain model functionality, the Command that represents an action to be performed by the tool, and finally, the Resource representing the result of the command on the tool. Thus, this work presents a framework that enables developers to model Web applications based on RFID panels in terms of these concepts. The paper also exposes how to extend the framework to build four applications that belong to absolutely different domains.

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DOI: 10.3217/jucs-019-12-1761

Authors: Alois Paulin

Abstract: In this paper we present a novel model for governing societies based on modern information technology, which neither relies on manual bureaucratic labour, nor depends on process-based e-government services. We analyse the flaws of the latter and argue that e-government is not feasible for sustainable governance due to permanently changing regulation; instead we propose a model in which people can govern themselves in a self-service manner by relying on constellations of data stored in a network of governmental databases to which citizens and government agents have read- and write access under conditions defined by then-valid regulation.

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DOI: 10.3217/jucs-019-12-1718

Authors: Khalil ur Rehman Laghari, Tiago Falk, Mansoor Hyder, Michael Haun, Christian Hoene, Noel Crespi

Abstract: Quality of Experience (QoE) is a human centric quality evaluation method which provides the blue print of human needs, perceptions, feelings and experiences with respect to a multimedia service. In a communications ecosystem, human interaction takes place alongside technological, contextual, and business domains, thus producing a holistic view on QoE formation. In this paper, we investigate the relationship between human perceived QoE and "context" for burgeoning 3-dimensional (3D) audio teleconferencing services. 3D audio teleconferencing applications are customizable by generating different virtual acoustic environments (VAE), where parameters such as virtual room size and competing talker conditions can be adjusted for a particular application. The impact of different VAE characteristics on perceived QoE, however, is still unknown. In this study, four QoE factors were investigated across different VAE scenarios. It was found that a) medium-size virtual rooms produce optimal perceived QoE, b) competing talkers of mixed gender could be easily located in the virtual space, and c) competing speaker gender had no significant effect on perceived audio quality.

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DOI: 10.3217/jucs-019-09-1295

Authors: Davide Anguita, Alessandro Ghio, Luca Oneto, Xavier Parra, Jorge Reyes-Ortiz

Abstract: In this paper we propose a novel energy efficient approach for the recog-nition of human activities using smartphones as wearable sensing devices, targeting assisted living applications such as remote patient activity monitoring for the disabledand the elderly. The method exploits fixed-point arithmetic to propose a modified multiclass Support Vector Machine (SVM) learning algorithm, allowing to better pre-serve the smartphone battery lifetime with respect to the conventional floating-point based formulation while maintaining comparable system accuracy levels. Experimentsshow comparative results between this approach and the traditional SVM in terms of recognition performance and battery consumption, highlighting the advantages of theproposed method.

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DOI: 10.3217/jucs-019-04-0581

Authors: Xuan Pham, Jason Jung, Ngoc Nguyen

Abstract: User rating is obviously considered to be an important type of feedback informationfor Interactive Recommendation System (RecSys). The quality and credibility of user ratings will eventually influence the quality of recommendation. However, in the real world, there areusually many inconsistent (e.g., mistakes and missing values) or incorrect user ratings. Therefore, expert-based recommendation framework has been studied to select the most relevant expertsregarding a certain item's attribute (or value). This kind of RecSys can i) discover user preferenceand ii) determine a set of experts based on attributes and values of items. In this paper, wepropose a consensual recommendation framework, by integrating multiple experts' ratings, to conduct a correction process which aims at modifying the ratings of other users in order to makethe system more effective. Since our work assumes that ratings from experts are assumed to be reliable and correct, we first analyze user profile so as to determine preferences and find out aset of experts. Next, we measure a minimal inconsistency interval (MinIncInt) that might contain incorrect ratings. Finally, we propose solutions to correct incorrect ratings based on ratings frommultiple experts. The results show that our solutions can improve both the ratings and the quality of RecSys on the whole.

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DOI: 10.3217/jucs-019-03-0383

Authors: Christin Seifert, Eva Ulbrich, Roman Kern, Michael Granitzer

Abstract: In text classification the amount and quality of training data is crucial for the performance of the classifier. The generation of training data is done by human labellers - a tedious and time-consuming work. To reduce the labelling time for single documents we propose to use condensed representations of text documents instead of the full-text document. These condensed representations are key sentences and key phrases and can be generated in a fully unsupervised way. We extended and evaluated the TextRank algorithm to automatically extract key sentences and key phrases. For representing key phrases we propose a layout similar to a tag cloud. In a user study with 37 participants we evaluated whether document labelling with these condensed representations can be done faster and equally accurate by the human labellers. Our evaluation shows that the users labelled tag clouds twice as fast and as accurately as full-text documents. While further investigations for different classification tasks are necessary, this insight could potentially reduce costs for the labelling process of text documents.

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DOI: 10.3217/jucs-019-01-0078

Authors: Aleksandar Spasić, Dragan Jankovic

Abstract: Three-dimensional television (3D TV) is expected by many to be the next step in the advancement of television. Due to significant financial exhaustion during the process of transition from analogue to digital production, low-budget broadcasters are not in the position to invest in a new 3D system. This paper proposes one model-driven framework approach to 3D TV production system applicable to and suitable for low-budget broadcasters. The target of the project is to define one of the possible scenarios for applying stereoscopic 3D technologies to low-budget TV production. 3D TV content production chain is described in the first step of the project. 3D TV production workflow is proposed in the second step. This step has two parts: the analyses of the production stages and their integral processes, and the definition of a problem space model which is suitable for low-budget 3D TV production. The preproduction, production and postproduction phases of a low-budget 3D TV production are described during the analyses of 3D TV content production workflow. The UML is used as a modelling tool. The behavioural description of a program production is modelled by the Use Case diagram. A state machine diagram is used to describe the dynamic behavioral representation and the life cycle of a 3D content. The flow and dependencies in 3D workflow are modelled by using the activity diagrams. The structural static representation (domain model) is presented by a class diagram.

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DOI: 10.3217/jucs-018-20-2893

Authors: Vladimir Tarasov

Abstract: Competence management has received much attention during recent years because it contributes to achieving organizational goals and solving problems such as improvement of information flow or competence supply. Many approaches were proposed to modelling competence and using competence models but there is still a lack of research into structures and utilisation of competence profiles in a competence management system. This article addresses this problem by proposing a formal approach to competence profile management. Four project cases are first analysed to elicit requirements of competence profile management, including competence profile operations. After that, an abstract model of competence profile management is formally defined based on the requirements. Finally, an ontology-based implementation of the abstract model is presented including a software architecture of a competence profile management system. The main contribution of this work is formalization of operations on competence profiles and ontology-based implementation of these operations. The proposed implementation architecture can facilitate construction of a competence profile management system.

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DOI: 10.3217/jucs-018-17-2493

Authors: Hongming Cai, Boyi Xu, Fenglin Bu

Abstract: Enterprises need a flexible and configurable IT architecture to meet complex business requirements agilely. For the purpose of bridging business modelling in build-time and application configuration in runtime seamlessly, a Conceptual Ontology-based Resource meta-Model (CORM) is proposed. Firstly, a resource meta-model is built as a referred model to describe business elements and relationships. Then, by means of ontology, these business elements are transformed into IT service-oriented components such as SOAP services, RESTful services and BPEL files. Referring to Model-View-Controller pattern, these service components are then configured in a runtime supported environment. Next, a state space defined by a resource array is built as the control mechanism to realize a completed IT system. Finally, a CORM-based supported Platform is built to support business modelling, service transformation and system configuration. The research indicates a new approach to develop and implement enterprise information systems in a more flexible and configurable way.

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DOI: 10.3217/jucs-018-17-2452

Authors: Ajantha Dahanayake, Bernhard Thalheim

Abstract: Although services are developed, used, applied and intensively discussed in nowadays IT practice, the concept of an IT service has not yet been introduced. Services are IT artifacts that can be used by many users in different context at different points of time in different locations and serve a certain purpose. They provide the data and functionality at the best point of time, in the agreed format and quality for the right user with the right location and context. We generalize some of the introduced notions such as the REA framework (resource-event-agent) and introduce a framework for conceptual modeling of IT service systems that is based on the classical rhetorical frame introduced by Hermagoras of Temnos (Quis, quid, quando, ubi, cur, quem ad modum, quibus adminiculis (W7: Who, what, when, where, why, in what way, by what means)). Services are primarily characterized by W4: wherefore (end), whereof (source), wherewith (supporting means), and worthiness ((surplus) value). Additionally, the purpose can be characterized by answering the why, whereto, when, and for which reason W4 questions. The secondary characterization W14H is given by characterizing user or stakeholder (by whom, to whom, whichever), the application domain (wherein, where, for what, wherefrom, whence, what), the solution they are providing (how, why, whereto, when, for which reason), and the additional context (whereat, whereabout, whither, when).

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DOI: 10.3217/jucs-018-17-2432

Authors: Ji Ma

Abstract: Risk assessment and access control are important issues in cloud computing. In this paper, we propose a formal approach to risk assessment for RBAC Systems, in which access control decisions are taken after consideration of risk assessment. The risk assessment method considers partial orderings on objects and actions, which allow us to effectively capture the notions of importance of objects and criticality of actions and then to determine the risk of assigning a specific role to a specific user. We in particular consider the cases of permission assignment and delegation assignment.

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DOI: 10.3217/jucs-018-17-2364

Authors: Juan Vara, Vasilios Andrikopoulos, Michael Papazoglou, Esperanza Marcos

Abstract: In the field of Service-Oriented Architecture (SOA) evolution is a key issue given the non-trivial nature of updating widely distributed and heterogeneous systems. With this in mind, in this work we used some of the technologies developed in the context of the Eclipse Modeling Framework (EMF) to provide a proof of concept of the possible synergy between Model-Driven Engineering (MDE) and Service Orientation. In particular, we present a DSL toolkit for modeling the structural part of Abstract Service Descriptions (ASDs) and the reasoning mechanism that assesses whether two versions of a service are compatible with respect to its consumers.

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DOI: 10.3217/jucs-018-14-2071

Authors: Henna Suomi, Kalevi Kilkki, Heikki Hämmäinen

Abstract: Recently, adding multipath capability in the Internet protocol suite has attracted increasing interest. By letting end hosts discover several paths to communicate, end-to-end multipath protocols aim to improve utilization rate of Internet resources. Although many proposals for end-to-end multipath communication exist, they have not reached significant deployment. Since the multipath protocols are mainly designed for open multi-stakeholder environments, understanding their economic impact is important. This paper introduces a model for assessing the value of the end-to-end multipath protocols from the end user perspective. Without a net benefit of the end user, the end-to-end multipath communication only results in the reallocation of costs and benefits in the Internet connectivity market. The model indicates that wireless devices having access to multiple independent access operators via similar or dissimilar access technologies are crucial in achieving end user value out of multipath communication. Initially, the end user value seems higher when the radio interfaces to access operators are active one at a time but later on, along with higher-energy batteries and lower-energy protocols, full benefit of multipath communication can be achieved. The value of multipath protocols depends on the effective path diversity and available capacity on the Internet.

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DOI: 10.3217/jucs-018-13-1760

Authors: Susan Elias, Vanaja Gokul, Kamala Krithivasan, Marian Gheorghe, Gexiang Zhang

Abstract: Membrane computing models (also known as P Systems) that solve optimisation problems using genetic algorithms, ant colony optimisation, quantum-inspired evolutionary algorithm and particle swarm optimisation have been defined and are efficiently used in several applications. This paper describes the design of a variant of the existing Distributed P system (dP system) that is augmented with new features that enable centralised monitoring and communication with all the other components of the distributed system. This proposed model is titled Monitored Distributed P System (MDP System) and its innovative application in performing Cross Layer Optimisation in wireless adhoc networks is also presented. In the proposed MDP System each node in the network is represented by a P system that can independently perform Cross Layer Optimisation using particle swarm optimisation. Discussions on the communication complexity of the proposed model and the experimental results presented are also suggestive of the fact that the proposed Monitored Distributed P System is suitable for real time optimisation in a dynamic and distributed environment.

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DOI: 10.3217/jucs-018-12-1608

Authors: Haralambos Mouratidis, Christos Kalloniatis, Shareeful Islam, Marc-Philippe Huget, Stefanos Gritzalis

Abstract: The increasing dependency on information systems to process and manage sensitive information requires the usage of development methods that support the development of secure and private information systems. The literature provides examples of methods that focus on security and privacy individually but fail to provide evidence of information systems development methods that consider security and privacy in a unified framework. Security and privacy are very much related, in particular certain security properties and mechanisms support the achievement of privacy goals. Without a development framework to support developers to explicitly model that relationship, conflicts and vulnerabilities can be introduced to a system design that might endanger its security. In this paper, we present our work in developing a framework that supports the unified analysis of privacy and security. In particular, we present a meta-model that combines concepts from security and privacy requirements methods, such as security and privacy goals, properties, constraints, and actor and process patterns within a social context. A real case study is employed to demonstrate the applicability of our work.

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DOI: 10.3217/jucs-018-11-1523

Authors: Yung Kim

Abstract: Various mobile-web services have expanded with the evolution of mobile Internet technologies and with the increasing variety of smart phones in the proliferating cloud computing environment. Web services for the integration of cloud applications/services can be evaluated at the utilization-level as well as the serviceability of the service on the server side in the management for cloud computing. In web activity, a web server can be a unified hub for web interactions as well as for the real-time estimation model of service-based parameters, i.e. utilization-level/serviceability for service monitoring. With the real-time estimation/analysis of the parameters in a web server for service-based contents delivery, the utilization-level and serviceability of a social-web name-card portal are presented. Empirical results are presented on the basis of the implementation of the real-time estimation scheme in a social-web name-card portal server for a cloud SNS.

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DOI: 10.3217/jucs-018-11-1501

Authors: Anton Joha, Marijn Janssen

Abstract: Software as a Service (SaaS) can be viewed as the fourth wave of outsourcing. SaaS is a relatively new type of service delivery model in which a service provider delivers its services over the web to many users on a pay per use or period basis. In the scarce literature available, the SaaS business model is almost always analyzed from the perspective of the service provider perspective, and rarely from the user organization. Using the unified business model conceptual framework, two case studies are investigated to understand the design choices underlying the SaaS business model from the user organization perspective. The analyses on the business model dimensions provided insight into the differences between the case studies and helped to identify eight discriminating design choices that are important when designing SaaS business models. These include the (1) SaaS service characteristics, (2) SaaS value source, (3) SaaS user target group, (4) data architecture configuration and tenancy model, (5) SaaS governance and demand/supply management core competencies, (6) cloud deployment model, (7) SaaS integration and provider strategy and the (8) SaaS pricing structure. An appeal is made for more research into the impact of cloud business models.

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DOI: 10.3217/jucs-018-11-1432

Authors: David Griffiths, Mark Johnson, Kris Popat, Paul Sharples, Scott Wilson

Abstract: Apache Wookie (incubating) has generated considerable interest within the context of Technology Enhanced Learning where it was developed, as well as in mobile applications. The origins of the system in providing services for IMS Learning Design are described, together with an introduction to the system's design and functionality. However, the areas where it has had success are distinct from the application area for which it was designed and developed. The implications of this for understanding user needs is analysed by using ideas drawn from sociology. The complexity of the relationship between the context of use and user needs, and the feedback loops between them is discussed, and the role of technological interventions as an element in a discourse is considered. It is proposed that this understanding of users needs, together with the experience of the development and use of Wookie, argues in favour of an interoperability strategy which focuses on relatively small sets of functional requirements, and avoidance where possible of specifications developed for particular application domains: an approach which may be characterised as piecemeal rather than Utopian.

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DOI: 10.3217/jucs-018-10-1238

Authors: Robert Bucki, Petr Suchánek

Abstract: Rapidly changing business environment requires new approaches and methods for supporting management systems in all types of companies. Modern companies doing business use e-commerce systems by default. One of the key areas of e-commerce systems is logistics and the supply chain. The optimal way to ensure the success of logistics and supply chains is to use the methods of modeling and simulation based on appropriate models and especially its mathematical representation. In this paper, authors highlight the customer-oriented model of the e-commerce system and deal with logistic optimization and simulations. As an example, a sample logistic structure which requires the adequate control approach is presented. This is realized by means of heuristic algorithms which are responsible for meeting the set criterion. Moreover, the criteria to either maximize the production output or minimize the lost flow capacity of the logistic system or minimize the tool replacement criterion are introduced. Equations of state are given in order to represent the flow of material through the logistic system.

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DOI: 10.3217/jucs-018-09-1152

Authors: Bratislav Predic, Dragan Stojanovic

Abstract: Recent advancements in sensor technologies resulted in the development of sensors with small dimensions and with power consumption that is low enough to be embedded in various mobile devices and which is widely integrated in vehicles. Such sensors can be extensively used to detect real-time traffic events and situations of user/vehicle in context-aware mobile applications. This paper explores the usage of a large number of anonymous mobile devices already involved in the road navigation function as mobile sources of traffic information. Apart from collecting location and speed data, which is extensively used today to calculate average trip time per road segment, we are exploring possibility of using an acceleration sensor integrated with a mobile device in order to efficiently and timely detect critical traffic events and redistribute this information to other drivers through proactive traffic information system. Such a system would be capable of warning drivers of 'near-accident' situations enhancing their situational awareness and general safety.

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DOI: 10.3217/jucs-018-08-1022

Authors: Xuan Pham, Jason Jung, Dosam Hwang

Abstract: Social media (e.g., Twitter and FaceBook) have been one of the most popular online communication channels to share information among users. It means the users can give (and have) cognitive influences to (and from) the others. Thus, it is important for many online collaborative applications to understand how the information can be propagated via such social media. In this paper, we focus on a social tagging system where users can easily exchange resources as well as their tags with other users. Given a certain tag from a temporal folksonomy, the social pulse can be established by counting the number of users (or resources). Particularly, we can discover meaningful relationship between tags by computing inducibility. To conduct experimentation, a tag search system has been implemented to collect a dataset from Flickr.

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DOI: 10.3217/jucs-018-06-0816

Authors: Raimundas Matulevičius, Haralambos Mouratidis, Nicolas Mayer, Eric Dubois, Patrick Heymans

Abstract: The need to consider security from the early stages of the development process of information systems has been argued by academics and industrialists alike, and security risk management has been recognised as one of the most prominent techniques for eliciting security requirements. However, although existing security modelling languages provide some means to model security aspects, they do not contain concrete constructs to address vulnerable system assets, their risks, and risk treatments. Furthermore, security languages do not provide a crosscutting viewpoint relating all three - assets, risks and risk treatments - together. This is problematic since, for a security analyst, it is difficult to detect what the potential security flaws could be, and how they need to be fixed. In this paper, we extend the Secure Tropos language, an agentand goal-oriented security modelling language to support modelling of security risks. Based on previous work, where we had observed some inadequacies of this language to model security risks, this paper suggests improvements of Secure Tropos semantics and syntax. On the syntax level we extend the concrete and abstract syntax of the language, so that it covers the security risk management domain. On the semantic level, we illustrate how language constructs need to be improved to address the three different levels of security risk management. The suggested improvements are illustrated with the aid of a running example, called eSAP, from the healthcare domain.

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DOI: 10.3217/jucs-018-01-0062

Authors: Jesus Boticario, Alejandro Rodriguez-Ascaso, Olga Santos, Emmanuelle Raffenne, Lydia Montandon, David Roldán, Félix Buendía

Abstract: The EU4ALL project (IST-FP6-034778) has developed a general framework to address the needs of accessible lifelong learning at Higher Education level consisting of several standards-based interoperable components integrated into an open web service architecture aimed at supporting adapted interaction to guarantee students' accessibility needs. Its flexibility has supported the project implementation at several sites with different settings and various learning management systems. Large-scale evaluations involving hundreds of users, considering diverse disability types, and key staff roles have allowed obtaining valuable lessons with respect to "how to adopt or enhance eLearning accessibility" at university. The project was evaluated at four higher education institutions, two of the largest in Europe and two medium-sized. In this paper, we focus on describing the implementation and main conclusions at the largest project evaluation site (UNED), which was involved in the project from the beginning, and thus, in the design process, and a medium-sized university that adopted the EU4ALL approach (UPV). This implies dealing with two well-known open source learning environments (i.e. dotLRN and Sakai), and considering a wide variety of stakeholders and requirements. Thus the results of this evaluation serve to illustrate the coverage of both the approach and developments.

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DOI: 10.3217/jucs-017-14-2009

Authors: Roberto Konow, Wayman Tan, Luis Loyola, Javier Pereira, Nelson Baloian

Abstract: There has been a continuous development of new clustering and prediction techniques that help customers select products that meet their preferences and/or needs from an overwhelming amount of available choices. Because of the possible huge amount of available data, existing Recommender Systems showing good results might be difficult to implement and may require a lot of computational resources to perform in this scenario. In this paper, we present a more simple recommender system than the traditional ones, easy to implement, and requiring a reasonable amount of resources to perform. This system clusters users according to the frequency an item has been visited by users belonging to the same cluster, performing a collaborative filtering scheme. Experiments were conducted to evaluate the accuracy of this method using the Movielens dataset. Results obtained, as measured by the F-measure value, are comparable to other approaches found in the literature which are far more complex to implement. Following this, we explain the application of this system to an e-content site scenario for advertising. In this context, a filtering tool is shown which has been developed to filter and contextualize recommended items.

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DOI: 10.3217/jucs-017-14-1931

Authors: Ana Cristina B. Garcia, Adriana Vivacqua, Thiago Tavares

Abstract: Democratic governments constantly need to make sense of their citizens' needs to make appropriate decisions that reflect the overall wishes and needs of the population. However, except for mandatory voting scenarios, a low rate of citizen participation in government decisions through democratic processes is an aspect that defies democracy itself. Brazil's participatory budget policy emphasizes people's direct guidance regarding certain budget allocations though group meetings. This paper presents mParticipation, an agent-based model for eliciting and answering citizen demands in a participatory government structure using mobile technology. A prototype system applied to the domain of public budget allocation domain demonstrates that it is feasible to provide effective computational support to participatory collective decision-making.

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DOI: 10.3217/jucs-017-12-1673

Authors: Michele Brocco, Florian Forster, Marc Frieß

Abstract: Open Innovation is a new paradigm that suggests including actors from inside as well as outside a company's boundaries in the innovation process. Open creativity refers to the creative phase in this process. In this article we investigate on open creativity support. We conducted interviews within companies in the German ICT sector to analyze the status quo of open creativity and the tools currently used to support it. In a second step we derive design guidelines and an architecture for IT systems supporting open creativity that lead to a holistic, 360ffi support for open creativity.

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DOI: 10.3217/jucs-017-12-1659

Authors: Rory Sie, Marlies Bitter-Rijpkema, Peter Sloep

Abstract: Several studies have shown that connecting to people in other networks foster creativity and innovation. However, it is often difficult to tell what the prospective value of such alliances is. Cooperative game theory offers an a priori estimation of the value of future collaborations. We present an agent-based social simulation approach to recommending valuable peers in networked innovation. Results indicate that power as such does not lead to a winning coalition in networked innovation. The recommendation proved to be successful for low-strength agents, which connected to high-strength agents in their network. Future work includes tests in real-life and other recommendation strategies.

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DOI: 10.3217/jucs-017-10-1511

Authors: Benedikt Schmidt, Todor Stoitsev, Max Mühlhäuser

Abstract: Intention-aware systems integrate aspects of context-aware and attentionaware systems for the identification and support of intention. Focusing intention is justified by the impact of intention on awareness and interaction with the world. Therefore, proactive user support mechanisms can be improved by including a representation of intention. In this paper, the externalization of intention in task models is discussed: existing task models are reviewed and activity schemes are proposed as task model for intention-aware systems. A framework for intention-aware systems is presented and discussed in detail.

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DOI: 10.3217/jucs-017-09-1299

Authors: Juan García, Francisco García-Peñalvo, Roberto Therón, Patricia Ordóñez de Pablos

Abstract: Usability is generally regarded as ensuring that software products are effective and efficient to use from the user's perspective. Diverse aspects that ensure the usability of a software product should be assessed during the different phases in its life cycle. The goal of usability testing is to evaluate whether or not a tool that is being developed will be usable by the end user in order to achieve the tasks for which it is being designed. This paper is targeted at describing the evaluation and the usability of OWL-VisMod, a visual modelling tool for OWL ontologies, from the point of view of the human-computer interaction. This evaluation is based on a user-centred approach and the use of questionnaires. The whole usability evaluation process is described and the results are discussed.

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DOI: 10.3217/jucs-017-07-1078

Authors: Syed Shahzad

Abstract: The user experience of any software or website consists of elements from the conceptual to the concrete level. These elements of user experience assist in the design and development of user interfaces. On the other hand, ontologies provide a framework for computable representation of user interface elements and underlying data. This paper discusses strategies of introducing ontologies at different user interface layers adapted from user experience elements. These layers range from abstract levels (e.g. User needs/Application Objectives) to concrete levels (e.g. Application User Interface) in terms of data representation. The proposed ontological framework enables device independent, semi-automated GUI construction which we will demonstrate at a personal information management example.

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DOI: 10.3217/jucs-017-02-0296

Authors: Jianming Yong

Abstract: This paper systematically discusses the security and privacy concerns for e-learning systems. A five-layer architecture of e-learning system is proposed. The security and privacy concerns are addressed respectively for five layers. This paper further examines the relationship among the security and privacy policy, the available security and privacy technology, and the degree of e-learning privacy and security. The digital identity attributes are introduced to e-learning portable devices to enhance the security and privacy of e-learning systems. This will provide significant contributions to the knowledge of e-learning security and privacy research communities and will generate more research interests.

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DOI: 10.3217/jucs-017-02-0164

Authors: Claudio Sapateiro, Nelson Baloian, Pedro Antunes, Gustavo Zurita

Abstract: We describe the design of a mobile collaborative tool that helps teams managing critical computing infrastructures in organizations, a task that is usually designated Business Continuity Management. The design process started with a requirements definition phase based on interviews with professional teams. The elicited requirements highlight four main concerns: collaboration support, knowledge management, team performance, and situation awareness. Based on these concerns, we developed a data model and tool supporting the collaborative update of Situation Matrixes. The matrixes aim to provide an integrated view of the operational and contextual conditions that frame critical events and inform the operators’ responses to events. The paper provides results from our preliminary experiments with Situation Matrixes.

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DOI: 10.3217/jucs-016-20-3138

Authors: Antonio Villegas, Antoni Olivé

Abstract: Visualizing and understanding large conceptual schemas requires the use of specific methods. These methods generate clustered, summarized, or focused schemas that are easier to visualize and understand. All of these methods require computing the importance of each entity type in the schema. In principle, the totality of knowledge defined in the schema could be relevant for the computation of that importance but, up to now, only a small part of that knowledge has been taken into account. In this paper, we extend seven existing methods for computing the importance of entity types by taking into account more relevant knowledge de_ned in the structural and behavioural parts of the schema. We experimentally evaluate the original and extended versions of these methods with three large real-world schemas. We present the two main conclusions we have drawn from the experiments.

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DOI: 10.3217/jucs-016-20-3102

Authors: Bernhard Thalheim

Abstract: Conceptual modelling is a widely applied practice and has led to a large body of knowledge on constructs that might be used for modelling and on methods that might be useful for modelling. It is commonly accepted that database application development is based on conceptual modelling. It is however surprising that only very few publications have been published on a theory of conceptual modelling. Modelling is typically supported by languages that are well-founded and easy to apply for the description of the application domain, the requirements and the system solution. It is thus based on a theory of modelling constructs. At the same time, modelling incorporates a description of the application domain and a prescription of requirements for supporting systems. It is thus based on methods of application domain gathering. Modelling is also an engineering activity with engineering steps and engineering results. It is thus engineering. The first facet of modelling has led to a huge body of knowledge. The second facet is considered from time to time in the scientific literature. The third facet is underexposed in the scientific literature. This paper aims in developing principles of conceptual modelling. They cover modelling constructs as well as modelling activities as well as modelling properties. We first clarify the notion of conceptual modelling. Principles of modelling may be applied and accepted or not by the modeler. Based on these principles we can derive a theory of conceptual modelling that combines foundations of modelling constructs, application capture and engineering. A general theory of conceptual modelling is far too comprehensive and far too complex. It is not yet visible how such a theory can be developed. This paper therefore aims in introducing a framework and an approach to a general theory of conceptual modelling. We are however in urgent need of such a theory. We are sure that this theory can be developed and use this paper for the introduction of the main ingredients of this theory.

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DOI: 10.3217/jucs-016-20-2956

Authors: Stephen Hegner

Abstract: Although a database view embodies partial information about the state of the main schema, the state of the view schema is a quotient (and not a subset) of the state of the main schema. It is the information content of the view state, the set of sentences which are true for that state, and not the state itself which is a subset of the information content of the state of the main schema. There are thus two dual approaches to modelling this partiality, one based upon structures, with a consequent quotient relationship, and another based upon logical theories, with a consequent subset relationship. In this work, a representation for database views is developed which combines these two approaches. The state-based representation is expanded so that the information content embodied in a wide class of views, including those defined by SPJ queries, is fully representable, thus permitting the view state to be modelled internally as a subset of the main database state. The utility of this framework is demonstrated with a simple solution to the uniqueness problem for view updates via constant complement.

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DOI: 10.3217/jucs-016-19-2862

Authors: Mark Melia, Claus Pahl

Abstract: Authoring of Adaptive Educational Hypermedia is a complex activity requiring the combination of a range of design and validation techniques. We demonstrate how Adaptive Educational Hypermedia can be transformed into CAVIAr courseware validation models allowing for its validation. The model-based representation and analysis of different concerns and model-based mappings and transformations are key contributors to this integrated solution. We illustrate the benefits of Model Driven Engineering methodologies that allow for interoperability between CAVIAr and a well known Adaptive Educational Hypermedia framework. By allowing for the validation of Adaptive Educational Hypermedia, the course creator limits the risk of pedagogical problems in migrating to Adaptive Educational Hypermedia from static courseware.

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DOI: 10.3217/jucs-016-17-2394

Authors: Namyoun Choi, Il-Yeol Song, Yuan An

Abstract: Educational standard s alignment , which matches similar or equivalent concepts of educational standards, is a necessary task for educational resource retrieval. In order to automate the alignment task, it is important to model the semantics of educational standards statements that are imperative mood sentences . In this paper, we present the MP (Materialization Pattern) model for representing the semantics of math educational standards for the purpose of aligning math educational standard s. This article first classifies math educational standard s statements into 16 types and then converts them to the MP model. The MP model is based on the Reed-Kellogg sentence diagrams, and created as MP diagrams using the UML notation. The MP model explicitly represents the semantics of the sentences by capturing math concepts and the cognitive process of the math concepts from math educational standards statements . The MP model is developed for automating the alignment of math educational standards.

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DOI: 10.3217/jucs-016-17-2353

Authors: Giovanni Giachetti, Manuela Albert, Beatriz Marín, Oscar Pastor

Abstract: In a model-driven development context, the definition (or selection) of an appropriate modeling language is a crucial task. OMG, in the model-driven architecture specification, recommends the use of UML for model-driven developments. However, the lack of semantic precision in UML has led to different model-driven approaches proposing their own domain-specific modeling languages in order to introduce their modeling needs. This paper focuses on customizing the UML association in order to facilitate its application in model-driven development environments. To do this, a well-defined process is defined to integrate the abstract syntax of a domain-specific modeling language that supports a precise semantics for the association construct in UML by means of the automatic generation of a UML profile. Finally, a brief example shows how the results obtained by the application of the proposed process can generate software products through a real model compilation tool.

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DOI: 10.3217/jucs-016-16-2232

Authors: Jinhyuk Choi, Geehyuk Lee, Junghoon Moon

Abstract: The fact that the World Wide Web is being used for various purposes also implies that users may have various information quality factors to consider according to their current context. In this regards, it is important for Web recommendation services to recognize what quality factors should be considered in current context in order to enhance user satisfaction. We showed that it is necessary to classify Web contexts based on the information quality factors users consider in their minds when they choose websites or Web pages. The results of user interviews showed that there are four quality factors: credibility, recency, popularity, and relevance. From survey data analysis, we recognized that user tasks can be clustered into two groups based on the quality factors that users consider. Finally, the results of log data analysis and performances of our proposed algorithm showed that it is possible to enable Web services to infer the context group. This result implies that context recognition is possible using the limited data that are collected at browser side.

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DOI: 10.3217/jucs-016-15-2099

Authors: Jason Jung

Abstract: It is important for mobile service providers to be aware of user contexts and to provide contextually relevant mobile services to users. Thereby, in this paper, we propose a novel mechanism for integrating online social networks, which are regarded as an important channel for exchanging and propagating contexts. To efficiently discover personal contexts of certain users, the contexts of their neighbors can be fused to provide mobile recommendation services to mobile subscribers. However, since the social network of each user is distributed across several systems, it has been difficult to integrate contexts from distributed social networks. Thereby, we mobilize all possible on- and off-line social networks to build an ego-centric social network. We implemented the proposed system by collecting the social network dataset from online sources (e.g., Facebook, Twitter, CyWorld, and co-authoring patterns in major Korean journals) and offline (e.g., co-participation patterns in a number of Korean domestic conferences). After the system was implemented, we provided mobile services to conference participants by sending text messages about time schedules of relevant presentations.

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DOI: 10.3217/jucs-016-14-1853

Authors: Dong Kim, JingTao Yao

Abstract: One of the main problems of web-based learning is staying motivated at a sufficientlevel. Learning games offering challenges and entertainment may stimulate student motivation for learning and mitigate this problem. Web-based learning support systems combined with learninggames may efficiently promote learning by encouraging student participation in learning. This study introduces a treasure hunt model, which represents the idea of inquiry-based learning usingset theory. We demonstrate this via a prototype of a web-based learning support system called OTHI, which employs an online treasure hunt game as the learning game. We integrate the soundlearning strategies of inquiry-based learning with the Web and online game technologies in this system. We expect that our learning support system will motivate students, and furnish an inter-active student-centered learning environment.

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DOI: 10.3217/jucs-016-13-1801

Authors: Chulmo Koo, Yulia Wati

Abstract: Mobile banking has been considered to be one of the most value-added and important mobile services currently available. Considering the fact that the penetration of this technology is undefined well, particularly in developing country, this study clarified the role of trust as a mediating variable in mobile banking environment. An empirical study was undertaken in Indonesia and the data of 100 respondents were collected. The empirical results provided strong evidence for the explanatory power of our research model. Firstly, we found that the trust mediated the effects of information quality to perceived usefulness and end-user satisfaction. Second, the both relationships of system quality and perceived usefulness and system quality and end-user satisfaction were partially mediated by trust. Third, trust also showed a direct effect on both end-user satisfaction and perceived usefulness. Lastly, the result provided support of the positive relationship between perceived usefulness and end-user satisfaction. Implication for both practice and further research were also discussed.

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DOI: 10.3217/jucs-016-13-1761

Authors: Kichan Nam, Nam Lee

Abstract: This study provides a conceptual framework with respect to service innovation, especially from a service-dominant logic (S-D logic) perspective. Even though innovation has been discussed as one of the most critical elements in enhancing the competitiveness of service industry, it was not clear how service innovation should be different from diverse types of existing innovation. The S-D logic provides a novel and valuable theoretical perspective that unifies the conventional literature on innovation. According to this new logic, four types of service innovation are presented based on two dimensions: the degree of co-creation and the degree of networked collaboration. We argue that service innovation can arise by the activity of value co-creation between firm and customer on the first dimension. On the second dimension, the firm needs to enhance their own capabilities for service innovation by applying the resources of all actors including suppliers and customers. Our framework indicates that it is critical for productive service innovation to make customers participate in value creation process and to integrate the dispersed resources held by participants. Examples are discussed with respect to different types of services innovation.

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DOI: 10.3217/jucs-016-13-1745

Authors: Jason Jung

Abstract: Most of ambient intelligence studies have tried to employ inductive methods (e.g., data mining) to discover useful information and patterns from data streams on sensor networks. However, since the spaces have been sharing their information with each other, it is difficult for such inductive methods to conduct the discovery process from the sensor streams intermixed from the heterogeneous sensor networks. In this paper, we propose an ontology-based middleware system to improve sustainability of context-aware service in the interconnected smart spaces. Two main challenges of this work are i) sensor data preprocessing (i.e., session identification) and ii) information fusion (i.e., information integration). The ontology in each sensor space can provide and describe semantics of data measured by each sensor. By aligning these ontologies from the sensor spaces, the semantics of sensor data captured inside can be compared. Thus, we can find out not only relationships between sensor streams but also temporal dynamics of a data stream. To evaluate the proposed method, we have collected sensor streams from in our building during 30 days. By using two well-known data mining methods (i.e., co-occurrence pattern and sequential pattern), the results from raw sensor streams and ones from sensor streams with preprocessing were compared with respect to two measurements recall and precision.

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DOI: 10.3217/jucs-016-13-1668

Authors: Olha Danylevych, Dimka Karastoyanova, Frank Leymann

Abstract: Services are quintessential in the current economical landscape. Enterprises and businesses at large rely on the consumption and providing of services to ensure their operations and to realize their business offers. That is, nowadays businesses all over the world are interconnected with each other by complex service-centric webs called service networks. The ubiquity and pervasiveness of service networks call for models, methods, mechanisms and tools to understand them and harness their potential. This paper investigates the modelling of the service networks with a focus on business relationships and exchanges of software services among the involved parties. The contribution of this work is threefold. Firstly, we provide an overview of what service networks modelling can offer in combination with Business Process Management (BPM) and Service Oriented Architecture (SOA) technologies. Secondly, we propose a formalism to model service networks that depicts them as aggregations of participants - e.g. enterprises or individuals - that offer, request, consume and provide services to each other. With the goal of providing a foundation for the alignment between service network- and business process models, we finally map the constructs of our service networks modelling formalism to the ones of the Business Process Modelling Notation (BPMN).

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