Latest Articles from JUCS - Journal of Universal Computer Science Latest 8 Articles from JUCS - Journal of Universal Computer Science https://lib.jucs.org/ Fri, 29 Mar 2024 15:55:14 +0200 Pensoft FeedCreator https://lib.jucs.org/i/logo.jpg Latest Articles from JUCS - Journal of Universal Computer Science https://lib.jucs.org/ Mobile Handoff with 6LoWPAN Neighbour Discovery Auxiliary Communication https://lib.jucs.org/article/108446/ JUCS - Journal of Universal Computer Science 30(2): 204-220

DOI: 10.3897/jucs.108446

Authors: Shanshan Jia, Gaukhar A. Kamalova, Dmytro Mykhalevskiy

Abstract: The importance of the topic under investigation stems from the burgeoning prominence of the Internet of Things (IoT) paradigm and the consequent imperative to devise and institute an efficacious methodology for neighbour detection that facilitates supplementary connections to mobile nodes. This research primarily aims to elucidate a mobile handover technique aligning with the neighbour discovery paradigm inherent in 6LoWPAN. The methodological framework employed herein amalgamates a systematic analysis of the foundational tenets governing 6LoWPAN communication standards over the IPv6 protocol in the context of IEEE 802.15.4aa personal wireless networks, supplemented with empirical evaluation of message propagation dynamics among discrete nodes of a designated personal wireless network. The findings of this investigation underscore the pre-eminence of the 6LoWPAN networking standard as a prime vehicle for bolstering the dependable communication of IoT's remote entities, contingent upon the utilization of the IPv6 communication protocol. This iteration of the Internet protocol is superior, particularly in surveillance contexts, given its expansive address capacity (128 bits) juxtaposed against its antecedent, the IPv4 protocol (32 bits). The inherent adaptability of this network connection augments the quality of mobile handover, especially when one considers the real-world application of 6LoWPAN's neighbour discovery auxiliary communication standard. The tangible implications of these findings beckon their potential utility in satiating the demands of IoT system users and actualizing the network collaboration ethos intrinsic to the 6LoWPAN communication standard.

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Research Article Wed, 28 Feb 2024 16:00:04 +0200
Detection of Size Modulation Covert Channels Using Countermeasure Variation https://lib.jucs.org/article/22669/ JUCS - Journal of Universal Computer Science 25(11): 1396-1416

DOI: 10.3217/jucs-025-11-1396

Authors: Steffen Wendzel, Florian Link, Daniela Eller, Wojciech Mazurczyk

Abstract: Network covert channels enable stealthy communications for malware and data exfiltration. For this reason, developing effective countermeasures for these threats is important for the protection of individuals and organizations. However, due to the large number of available covert channel techniques, it is considered impractical to develop countermeasures for all existing covert channels. In recent years, researchers started to develop countermeasures that (instead of only countering one particular hiding technique) can be applied to a whole family of similar hiding techniques. These families are referred to as hiding patterns. Considering above, the main contribution of this paper is to introduce the concept of countermeasure variation. Countermeasure variation is a slight modification of a given countermeasure that was designed to detect covert channels of one specific hiding pattern so that the countermeasure can also detect covert channels that are representing other hiding patterns. We exemplify countermeasure variation using the compressibility score, the ε-similarity and the regularity metric originally presented by Cabuk et al. All three methods are used to detect covert channels that utilize the Inter-packet Times pattern and we show that countermeasure variation allows the application of these countermeasures to detect covert channels of the Size Modulation pattern, too.

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Research Article Thu, 28 Nov 2019 00:00:00 +0200
Maximum Capacity Overlapping Channel Assignment Based on Max-Cut in 802.11 Wireless Mesh Networks https://lib.jucs.org/article/23822/ JUCS - Journal of Universal Computer Science 20(13): 1855-1874

DOI: 10.3217/jucs-020-13-1855

Authors: Ming Yang, Bo Liu, Wei Wang, Junzhou Luo, Xiaojun Shen

Abstract: By exploiting multi-radio multi-channel technology, wireless mesh networks can effectively provide wireless broadband access to the Internet for mobile users. Due to the limited number of orthogonal channels, overlapping channel assignment is one of the main factors that greatly affect the network capacity. However, current results in this area are not so satisfying. In this paper, we first propose a model for measuring achieved network capacity in MR-WMNs. Then we prove that finding an optimal overlapping channel assignment in a given MR-WMN with odd number of channels, is equivalent to finding an optimal assignment by only using its orthogonal channels. This theory allows us to use fewer channels to solve complicated channel assignment problems. Third, we prove that in 802.11b/g MR-WMN the simplified optimization problem is a Max-3-Cut problem. Although this problem is NP-hard, it has an efficient approximation algorithm that achieves approximation ratio of 1.19616 probabilistically by using the algorithm for Max-Cut whose approximation ratio is 1.1383 probabilistically. Based on the algorithm for Max-Cut, this paper proposes Max-Cut based channel assignment (MCCA) which uses a heuristic method to adjust the result produced by the Max-Cut algorithm to achieve an even better result. Finally, we perform extensive simulations to compare the MCCA with a state-of-the-art Tabu-Search based algorithm. The results show that the Max-Cut based overlapping channel assignment algorithm effectively and efficiently improves on the network capacity compared with existing algorithms.

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Research Article Fri, 28 Nov 2014 00:00:00 +0200
Network Planning for WiMAX-R Networks https://lib.jucs.org/article/23458/ JUCS - Journal of Universal Computer Science 18(9): 1194-1217

DOI: 10.3217/jucs-018-09-1194

Authors: Qiang Liu, Min Chen, Jie Zhang, Bingwen Shen, Zhong Chu

Abstract: In this paper, a novel network planning process of the Mobile WiMAX for Railway (WiMAX-R) network is proposed. We first analyze the factors need considered in network planning. After introducing the WiMAX-R network architecture, the WiMAX-R network planning process is presented in detail. The process comprises application analysis, capacity prediction, network parameters configuring, coverage planning, handover planning and network simulation validation. In each step, Mobile WiMAX technical features and railway environment characters are both take into consideration. Finally, we simulated a WiMAX-R planning example based on OPNET platform. The simulation results showed that the designed WiMAX-R network can perfectly satisfy the applications’ QoS requirements.

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Research Article Tue, 1 May 2012 00:00:00 +0300
Optimization of Gateway Deployment with Load Balancing and Interference Minimization in Wireless Mesh Networks https://lib.jucs.org/article/30039/ JUCS - Journal of Universal Computer Science 17(14): 2064-2083

DOI: 10.3217/jucs-017-14-2064

Authors: Junzhou Luo, Wenjia Wu, Ming Yang

Abstract: In a wireless mesh network (WMN), gateways act as the bridges between the mesh backbone and the Internet, and significantly affect the performance of the whole network. Hence, how to determine the optimal number and positions of gateways, i.e., gateway deployment, is one of the most important and challenging topics in practical and theoretical research on designing a WMN. Although several approaches have been proposed to address this problem, few of them take load balancing and interference minimization into account. In this paper, we study the Load-balancing and Interference-minimization Gateway Deployment Problem (LIGDP), which aims to achieve four objectives, i.e. minimizing deployment cost, minimizing MR-GW path length, balancing gateway load and minimizing link interference. We formulate it as a multi-objective integer linear program (ILP) issue first, and then propose an efficient gateway deployment approach, called LIGDP Heuristic. The approach joints two heuristic algorithms, i.e., MSC-based location algorithm (MLA) and load-aware and interference-aware association algorithm (LIAA), to determine gateway positions and construct GW-rooted trees. Simulation results not only show that the trade-off between deployment cost and network performance can be achieved by adjusting R-hop, GW throughput and MR throughput constraints, but also demonstrate that, compared with other existing approaches, LIGDP Heuristic performs better on MR-GW path, load balancing and interference minimization without deploying more gateways.

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Research Article Sat, 1 Oct 2011 00:00:00 +0300
Drives and Barriers for Development of Broadband Access - CE Perspective https://lib.jucs.org/article/28999/ JUCS - Journal of Universal Computer Science 14(5): 717-730

DOI: 10.3217/jucs-014-05-0717

Authors: Zbigniew Hulicki

Abstract: Development of e-services in the CE (Central European) countries d epends on a number of factors which can result in overcoming or extending digital divide between the "new" and "old" EU member states. These factors comprise both drives of and barriers to development of broadband access and growth of e-services. This paper provides insight into the environment for the CE mass-market broadband adoption, and examines each of the factors that condition this adoption: novel approaches to increase ICT penetration; clear policy and legal regulations; segmented service offerings for specific user needs in such markets ; and innovative pricing schemes and service packages.

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Research Article Sat, 1 Mar 2008 00:00:00 +0200
Case Studies in Tele-Education: Research and Projects https://lib.jucs.org/article/28483/ JUCS - Journal of Universal Computer Science 11(9): 1555-1567

DOI: 10.3217/jucs-011-09-1555

Authors: Miguel A. Vega-Rodríguez, Juan Gómez-Pulido, Juan Sánchez-Pérez

Abstract: ICT (Information and Communication Technologies) are a very important educational resource at the present time because they allow place and time limitations to be overcome and therefore reduce costs. In addition, multimedia applications offer a set of characteristics in order to improve learning by means of interactive activities. For these reasons, we believe it is important to devote efforts to the development of proposals and prototypes for teaching via Internet. Since 1998, our research group has been focused on this objective and working on diverse projects such as SD2I, TEDA or PDIWeb. In this paper we overview all these projects, presenting a general description of each web platform, as well as the tools and methods used for their implementation. This paper also includes the results obtained after the use of each platform and the feedback from surveys. In this way, several conclusions are presented in the last section of this paper.

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Research Article Wed, 28 Sep 2005 00:00:00 +0300
LAN Access Over ISDN https://lib.jucs.org/article/27205/ JUCS - Journal of Universal Computer Science 2(1): 20-33

DOI: 10.3217/jucs-002-01-0020

Authors: Franz Pucher, Herbert Leitold, Reinhard Posch

Abstract: This paper describes local area network (LAN) access using public wide area data networks and problems that arise when using integrated services digital network (ISDN) technology [Stallings 90] [Thachenkary 93]. To date mainly modem connections at serial lines with a terminal port have been the standard remote access technique. With ISDN it is foreseen that these modem lines will be replaced rather soon. This is mainly due to the fact that ISDN offers a more adequate bandwidth and is much more consistent from the point of view of access and embedding. This paper demonstrates in the main section a router-based solution for enhanced call management. One of the main advantages is the separation of the strategic module which defines the behavior and thus allows for a number of active connections exceeding the number of ports. It also addresses traffic and access control in the network environment.

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Research Article Sun, 28 Jan 1996 00:00:00 +0200