Vol. 12 No. 9 SEP 2014
Vol. 12 No. 9 SEPTEMBER 2014 International Journal of Computer Science and Information Security
Publication SEPTEMBER 2014, Volume 12 No. 9 (Download Full Journal) (Archive) (Download 2)
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Copyright © IJCSIS. This is an open access journal distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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1. Paper 31081412: An Improved UGS Scheduling with QoE Metrics in WiMAX Network (pp. 1-6)
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Tarik ANOUARI (1), Abdelkrim HAQIQ (1, 2)
(1) Computer, Networks, Mobility and Modeling laboratory, Department of Mathematics and Computer, FST, Hassan 1st University, Settat, Morocco
(2) e-NGN Research group, Africa and Middle East
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Abstract — WiMAX (Worldwide Interoperability for Microwave Access) technology has emerged in response to the increasing demand for multimedia services in the internet broadband networks. WiMAX standard has defined five different scheduling services to meet the QoS (Quality of Service) requirement of multimedia applications and this paper investigates one specific scheduling service, i.e. UGS scheduling. In parallel, it was observed that in the difference of the traditional quality assessment approaches, nowadays, current researches are centered on the user perception of the quality, the existing scheduling approaches take into account the QoS, mobility and many other parameters, but do not consider the Quality of Experience (QoE). In order to control the packet transmission rate so as to match with the minimum subjective rate requirements of each user and therefore reduce packet loss and delays, an efficient scheduling approach has been proposed in this paper. The solution has been implemented and evaluated in the WiMAX simulation platform developed based on NS-2. Simulation results show that by applying various levels of MOS (Mean Opinion Score) the QoE provided to the users is enhanced in term of jitter, packet loss rate, throughput and delay.
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Keywords: WiMAX, QoE, QoS, UGS, NS-2.
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2. Paper 31081414: Discovering Yearly Fuzzy Patterns (pp. 7-12)
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F. A. Mazarbhuiya, College of Computer Science and IT, Albaha University, Albaha, KSA
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Abstract — Extracting fuzzy patterns from temporal datasets is an interesting data mining problems. An example of such pattern is yearly fuzzy pattern where a pattern holds in a certain fuzzy time interval of every year. It involves finding frequent sets and then association rules that holds in certain fuzzy time intervals (late summer or early winter etc.) in every year. In most of the previous works, the fuzziness is user-specified. However, in some applications, user may not have enough prior knowledge about the datasets under consideration and may miss some fuzziness associated with the problem. It may also the case that user may not be able to specify the fuzziness due to limitation of natural language. In this paper, we propose a method of extracting patterns that holds in certain fuzzy time intervals of every year where fuzzy time interval is generated by the method itself. The efficacy of the method is demonstrated with experimental results.
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Keywords- Frequent itemsets, Superimposition of time intervals, Fuzzy time intervals, Right reference functions, left reference functions, Membership functions.
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3. Paper 31081417: Assessment of Non Transmittable Codewords Enhancement to Viterbi Algorithm Decoding (pp. 13-18)
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Salehe I. Mrutu (1), Anael Sam (2) and Nerey H. Mvungi (3)
(1, 2) School of Computational and Communication Science and Engineering (CoCSE), Nelson Mandela African Institution of Science and Technology (NM-AIST), Arusha, Tanzania
(3) College of Information and Communication Technologies, University of Dar Es Salaam (UDSM), Dar Es Salaam, Tanzania
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Abstract — Researchers have shown that practical mobile communication channels introduce errors that are concentrated in a certain locality rather than random errors. These are burst errors caused by deep fading of the wireless channel or a lightning strike. The existing Viterbi Algorithm (VA) capable of correcting random errors is inefficient in correcting burst errors and therefore resulting in unacceptable amount of residual errors. This paper presents an assessment of Non-Transmittable Codewords (NTCs) enhancement technique to VA in decoding the received signals subjected to burst errors that may occur in poor channels. A hard decision, 1/2 rate and constraint length K is equal to 3 Viterbi Algorithm decoding technique, Binary Phase-Shift Keying (BPSK) and Additional White Gaussian Noise (AWGN) are components used in MATLAB software based simulation when assessing the proposed technique. Applying 6NTCs to VA decoder enables the decoder to reduce 83.7 percent of its residual errors. However, the technique reduces the encoder’s data transmission rate from 1/2 to 1/6.
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Keywords-Locked Convolutional encoder; Bust errors; Residual errors; Non-Transmittable Codewords (NTCs); Viterbi Algorithm Decoding; Data Interleaver
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4. Paper 31081418: An Integrated Digital Academic Repository Model for Higher Learning Institutions (Case of Tanzania) (pp. 19-27)
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Martha Mhongole, School of computational communication science and engineering, NM-AIST, Arusha, Tanzania
Loserian Laizer, School of computational communication science and engineering, NM-AIST, Arusha, Tanzania
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Abstract — This paper explores the current existing models and technologies used in knowledge creation, knowledge sharing and knowledge dissemination practices in Higher Learning Institutions (HLIs) of Tanzania and proposes the model for the development of an Integrated Digital Academic Repository that enhances management, sharing and dissemination of Scholarly works produced in HLIs of Tanzania. The proposed model is presented and described in the paper. The study was carried out in three HLI using questionnaires, interview, observation and review of literatures. The findings show that, universities produce wide range of intellectual outputs such as research articles, learning materials, theses and technical reports. More than half population involved in the study create and store their intellectual outputs in personal computer hard drives while others store in internet cloud servers and departmental web servers. Moreover, sharing and dissemination of Intellectual output is done through internet i.e. Emails, social network, institution website and cloud servers, journal publication, seminar presentations, posters and printed copies in libraries. The identified methods proven to be unreliable and hindering availability and accessibility of scholarly works. Thus the proposed model provides a central system through which intellectual outputs will be collected, organized and archived and disseminated through it. The paper concludes with the conceptual framework of the proposed system, whereas design and development carried forward to be our future work.
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Keywords- Higher learning institution, intellectual output, knowledge management, knowledge sharing, model, digital repository
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5. Paper 31081425: Finding Untraced Fuzzy Association Rules (pp. 28-30)
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F. A. Mazarbhuiya, College of Computer Science and IT, Albaha University, KSA
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Abstract — Fuzzy association rules are rules of the form “If X is A then Y is B” where X and Y are set of attributes and A, B are fuzzy sets that describe X and Y respectively. In most of fuzzy association rules mining problem fuzziness is specified by users. The users usually specify the fuzziness based on their understanding of the problem as well as the ability to express the fuzziness by natural language. However there exist some fuzziness which cannot be expressed using natural language due its limitation. In this paper we propose a method of extracting fuzzy association rules which cannot be traced by usual methods. We suggest a way of extracting these rules.
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Keywords- Fuzzy set, Association rules, Fuzzy interval, Certainty factor, Significance factor, Between Operation.
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6. Paper 31081428: A Novel Approach to Address Information Leakage Attacks Based on Machine Virtualization (pp. 31-42)
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Omar Hussein, Nermin Hamza, Hesham Hefny
Computer and Information Sciences Department, Institute of Statistical Studies and Research, Cairo University, Egypt
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Abstract — In a traditional non-virtualized computer system the whole software stack is highly vulnerable to security breaches. This is mainly caused by the coexistence of deployed security systems in the same space as the potentially compromised operating system and applications that often run with administrative privileges. In such a structure, compromising, bypassing, disabling, or even subverting deployed security systems become trivial. Machine virtualization provides a powerful abstraction for addressing information security issues. Its isolation, encapsulation, and partitioning properties can be leveraged to reduce computer systems’ susceptibility to security breaches. This paper demonstrates that machine virtualization when employed and synthesized with cryptography would preserve information confidentiality even in an untrusted machine. It presents a novel information security approach called Virtualized Anti-Information Leakage (VAIL). Its objective is to thwart malicious software and insiders’ information leakage attacks on sensitive files after decryption in potentially compromised computer systems. VAIL’s defenses are evaluated against a variety of information leakage attacks including: (1) direct attacks launched on sensitive files from an untrusted virtual machine, and a compromised virtual machine monitor; and (2) indirect attacks exploiting covert storage and timing channels. Based on the security evaluation, it is concluded that VAIL effectively complied with the security requirements, and met its objective.
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Index Terms—Information Security; Information Leakage; Machine Virtualization; Malicious Software; Insider Threat
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7. Paper 31081429: Performance Analysis of Speech Quality in VoIP during Handover (pp. 43-48)
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M. Yousef & M. Fouad
Electronics & Communications Dept., Faculty of Eng., Zagazig Uni., Egypt.
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Abstract — Quality of Service is a very important factor to determine the quality of a VoIPcall. Different subjective and objective models exist for evaluating the speech quality inVoIP. E-model is one of the objective methods of measuring the speech quality; it considers various factors like packet loss, delay and codec impairments. The calculations of E-model are not very accurate in case of handovers – when a VoIP call moves from one wireless LAN to another. This paper conducted experimental evaluation of performance of E-model during handovers and proposes a new approach to accurately calculate the speech quality of VoIP during handovers and make MOS calculator which take the results through. A detailed description of the experimental setup and the comparison of the new approach with E-model is presented in this work.
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8. Paper 31081433: Web Users Clustering Analysis (pp. 49-52)
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Hooman Rokham, Computer Engineering Department, Shahre-e-Qods Branch, Islamic Azad University, Shahr-e-Qods, Iran
Hale Falakshahi, Computer Engineering Department, Science and Research Branch, Islamic Azad University, Neyshabur, Iran
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Abstract — As one of the most important tasks of web usage mining, web user clustering, which establishes groups of users exhibiting similar browsing patterns, provides useful knowledge to personalized web services. There are many clustering algorithm. In this paper, users' similarity is calculated then a comparative analysis of two clustering algorithms namely K-means algorithm and hierarchical algorithm is performed. Web users are clustered with these algorithms based on web user log data. Given a set of web users and their associated historical web usage data, we study their behavior characteristic and cluster them. In terms of accuracy K-means produces better results as compared to hierarchical algorithm.
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Keywords-clustering; K-means algorithm; hierarchical algorithm
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9. Paper 31081440: A Comparative Analysis of Dynamic Scheduling Algorithms versus the Round-Robin Scheduling Algorithm (pp. 53-60)
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Vilma Tomço, University of Tirana, Faculty of Mathematics, Statistics and Applied Informatics, Tirana, Albania
Anduela Dervishi, Polytechnic University of Tirana, Faculty of Mathematical and Physical Engineering, Tirana, Albania
Elton Lika, Polytechnic University of Tirana, Faculty of Information Technology, Department of Informatics Engineering, “Mother Teresa” Square, Tirana, Albania
Igli Tafa, Polytechnic University of Tirana, Faculty of Information Technology, Department of Informatics Engineering
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Abstract - Scheduling is one of the most important concepts in Operating Systems. One of the most popular algorithms is Round - Robin, which switches the processes after running the set Time Quantum (TQ). TQ value affects the average time of Waiting and Turnaround, and the number of Context Switches (CS). This definition can be static, which does not change, and dynamic, calculated cycle after cycle. This review builds on the study of new techniques for the determination of TQ dynamically. Initially is shown that in all cases this method is efficient and then we rank the most important techniques used. We look at how each works and the differences and their similarities. We will observe their efficiency in different parameters and the conditions in which they are effective. Finally we show that MDTQRR is most effective, minimizing the number of CS and Harm is the most effective in AVG (Waiting and Turnaround) Time.
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Key words - Round-Robin, Quantum Time, Waiting Time, Turnaround Time, Context Switch, ready queue.
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