An Extended E-Learning System Architecture: Integrating Software Tools within the E-Learning Portal

Zuhoor Al-Khanjari, Swamy Kutti, and Muna Hatem 

Department of Computer Science, Sultan Qaboos University, Sultanate of Oman 

Abstract: IT-based Higher education is found to be a feasible and economical solution in improving the traditional education model [2, 14]. Consequently the e-learning portals have been evolved as experimental tools in implementing online courses with the existing classroom education [3, 6, 13]. For an on-line course to be successful, it is essential to provide a necessary resource environment available in on-line. This expects designers to implement their courses standing alone without a third party dependency. An experimental study has been carried to verify the feasibility of implementing a system architecture that can support course-related resources in stand-alone mode. This paper explains the development of a prototype system architecture which results by extending the services of a portal by integrating software tools used in the related courses. The resulting architecture is simple, distributed and cost effective. The supporting experimental work has been carried out on the test bed around the e-learning portal WebCT that is currently available in Sultan Qaboos University (SQU).

Keywords: Workgroup learning, web-server, MyCoursesServer, application server, Unix network server, WebCT

 Received June 13, 2004; accepted February 25, 2005.

Image Segmentation and Edge Detection Based on Chan-Vese Algorithm

Nassir Salman

Computer Science Department, Zarqa Private University, Jordan

Abstract: The main idea in this paper is to detect regions (objects) and their boundaries, and to isolate and extract individual components from a medical image. This can be done using K-means firstly to detect regions in a given image. Then based on techniques of curve evolution, Chan-Vese for segmentation and level sets approaches to detect the edges around each selected region. Once we classified our images into different intensity regions based on K-means method, to facilitate separating each region with its boundary and its area individually in the next steps. Then we detect regions whose boundaries are not necessarily defined by gradient using Chan-Vese algorithm for segmentation. In the level set formulation, the problem becomes a mean-curvature flow like evolving the active contour, which will stop on the desired boundary of our selected region which results from K-means step. The final image segmentation results are one closed boundary per actual region  in the image and a segmented map.

Keywords: Chan-Vese approach, K-means, active counters, level set methods, segmentation, edge detection. 

MOSIX Evaluation on a Linux Cluster

Najib Kofahi¹, Saeed Al Zahrani², and Syed Manzoor Hussain³

¹Department of Computer Sciences, Yarmouk University, Jordan

²Saudi Aramco, SA

 ³Dept. of Information and Computer Science, King Fahd University of Petroleum and Minerals, SA 

Abstract: Multicomputer Operating System for Unix (MOSIX) is a cluster-computing enhancement of Linux kernel that supports preemptive process migration. It consists of adaptive resource sharing algorithms for high performance scalability by migrating processes across a cluster. Message passing Interface (MPI) is a library standard for writing message passing programs, which has the advantage of portability and ease of use. This paper highlights the advantages of a process migration model to utilize computing resources better and gain considerable speedups in the execution of parallel and multi-tasking applications. We executed several CPU bound tests under MPI and MOSIX. The results of these tests show the advantage of using MOSIX over MPI. At the end of this paper, we present the performance of the executions of those tests, which showed that in some cases improvement in the performance of MOSIX over MPI can reach tens of percents.

Keywords: High performance computing, performance evaluation, Linux cluster, MOSIX, MPI, process migration. 

Partial Automation of Sensitivity Analysis by Mutant Schemata Approach

Zuhoor Al-Khanjari

Department of Computer Science, Sultan Qaboos University, Oman

Abstract: According to Voas et al. testability is defined as the ease with in which faults may manifest themselves as failures when the software undergoes the testing process [39]. They also went further by introducing an approach for measuring sensitivity in terms of estimates from Propagation, Infection, and Execution (PIE) analyses of software and calculating the testability of a program through sensitivity estimate. Their testability calculations ‘by hand’ to determine the stability of the PIE analysis technique had drawbacks such as more time-consuming, high cost and less precision in the overall results [4]. Particularly the infection analysis part is one of the most expensive, sophisticated and time-consuming component of the PIE analysis technique. In order to solve this problem an investigation has been carried out by the author for establishing the feasibility of automating (or partially automating) the PIE analysis technique by means of a fast, and computationally less expensive Mutant Schemata Generation (MSG) approach [2]. An MSG-Infection tool has been developed to automate PIE analyses partially. This paper explains the use of MSG-Infection tool in automating the sensitivity analysis of C-programs and presents the results demonstrating the performance improvements achieved due to the MSG-Approach.

Keywords: Testability analysis, PIE technique, mutation testing, mutant schemata approach, Mothra mutation system, PiSCES, MSG-Infection tool. 

MOSIX Evaluation on a Linux Cluster

Najib Kofahi¹, Saeed Al Zahrani², and Syed Manzoor Hussain³

¹Department of Computer Sciences, Yarmouk University, Jordan

²Saudi Aramco, SA

³Dept. of Information and Computer Science, King Fahd University of Petroleum and Minerals, SA

Abstract: Multicomputer Operating System for Unix (MOSIX) is a cluster-computing enhancement of Linux kernel that supports preemptive process migration. It consists of adaptive resource sharing algorithms for high performance scalability by migrating processes across a cluster. Message passing Interface (MPI) is a library standard for writing message passing programs, which has the advantage of portability and ease of use. This paper highlights the advantages of a process migration model to utilize computing resources better and gain considerable speedups in the execution of parallel and multi-tasking applications. We executed several CPU bound tests under MPI and MOSIX. The results of these tests show the advantage of using MOSIX over MPI. At the end of this paper, we present the performance of the executions of those tests, which showed that in some cases improvement in the performance of MOSIX over MPI can reach tens of percents. 

Keywords: High performance computing, performance evaluation, Linux cluster, MOSIX, MPI, process migration.

 Received July 28, 2004; accepted September 30, 2004  

Integrating Multicasting and Hash Algorithm

 to Support Host Mobility

Sahar Al-Talib, Borhanuddin Mohd Ali, and Sabira KhatunDepartment of Communication and Networking System, Universiti Putra Malaysia, Malaysia 

Abstract: This paper explains a framework that has been proposed to construct a dynamic delivery tree for the Mobile Node (MN) movement in a mobile IPv6 network. The branches of the tree constitute the shortest paths from the packet source to each of the visited locations. The tree is dynamic so that the branches grow and shrink to reach the MN when necessary. This architecture is multicast-based, in which a mobile node is assigned a multicast address and the correspondent nodes send packets to that multicast group. As the mobile node moves to a new location, it joins the multicast group through the new location and prunes through the old location. Hash Algorithm has been implemented as a mechanism for the MN to join and leave a multicast group. Dynamics of the multicast tree provide for smooth handoff, efficient routing and conservation of network bandwidth. To allow a smooth handoff, the MN should not prune the old location until it starts receiving packets from the new location. The performance of the proposed mechanism was evaluated through a simulation model built for this purpose. The simulation results showed that the dynamics of joining and leaving the group directly affect handoff latency and smoothness, as a result it conserved Radio Frequency (RF) bandwidth.

Key words: Mobile IPv6, multicast group, hash algorithm, handover. 

Received July 27, 2004; accepted December 28, 2004  

A Virtual Cooperative Learning Environment

Using Human Companion

Tahar Bouhadada and Mohamed Tayeb Laskri

Research Group on Artificial Intelligence, University of Annaba, Algeria

Abstract: This paper describes the architecture of an Interactive Learning Environment (ILE) on the internet using companions which one is a human and geographically distant of the learning site. The achieved system rests on a three-tier customer/server architecture (customer, web server, data and applications server) where human and software actors can communicate via the internet and uses the DTL learning strategy. It contains five main actors: a tutor actor in charge to guide the learner; a system actor whose role is to manage and to control the accesses to the system; a teacher actor in charge of the management and the updating of the different bases; a learner actor who represents the main actor of the system for whom is dedicated the teaching. Also, a learning companion actor whose role can be sometimes as an assistant, and other times as a troublemaker.   

Keywords: Interactive learning environment, LCS, DTL strategy, companion, distant learning, troublemaker. 

Received July 20, 2004; accepted September 26, 2004 

Incremental Genetic Algorithm

Nashat Mansour¹, Mohamad Awad¹, and Khaled El-Fakih²

¹Computer Science Division, Lebanese American University, Lebanon

²Department of Computer Science, American University of Sharjah, UAE 

Abstract: Classical Genetic Algorithms (CGA) are known to find good sub-optimal solutions for complex and intractable optimization problems. In many cases, problems undergo frequent minor modifications, each producing a new problem version. If these problems are not small in size, it becomes costly to use a genetic algorithm to reoptimize them after each modification. In this paper, we propose an Incremental Genetic Algorithm (IGA) to reduce the time needed to reoptimize modified problems. The idea of IGA is simple and leads to useful results. IGA is similar to CGA except that it starts with an initial population that contains chromosomes saved from the CGA run for the initial problem version (prior to modifying it). These chromosomes are best feasible and best infeasible chromosomes to which we apply two techniques in order to ensure sufficient diversity within them. To validate the proposed approach, we consider three problems: Optimal regression software testing, general optimization, and exam scheduling. The empirical results obtained by applying IGA to the three optimization problems show that IGA requires a smaller number of generations than those of a CGA to find a solution. In addition, the quality of the solutions produced by IGA is comparable to those of CGA. 

Keywords: Exam scheduling, general optimization, incremental genetic algorithms, optimization algorithms, regression testing, soft computing.

A New Approach in Key Generation and Expansion in Rijndael Algorithm

Naim Ajlouni¹, Asim El-Sheikh², and Abdullah Abdali Rashed²

¹Amman Arab University for Graduate Studies, Jordan

²Arab Academy for Banking and Financial Science, Jordan

 Abstract: This paper presents a new algorithm that simplifies the process of generating and expanding cipher key, which is considered one of the most important elements in ciphering process. The algorithm generates a random pool of keys (long size key), this key is sent to the authorized receiver. During the ciphering process the algorithm will select the schedule keys randomly from the pool of keys. The receiver will be given the index of the first element in the schedule key and the key length. During the deciphering process the deciphering algorithm will use the received information to extract the schedule from the original pool, this key is then used to decipher the ciphered data block without any key re-expansion.

 Keywords: Rijndael block cipher, AES, key generation, key expansion.  

Speaker Recognition for Wire/Wireless Communication Systems

Mohamed Abdel Fattah, Fuji Ren, and Shingo Kuroiwa

Faculty of Engineering, The University of Tokushima, Japan

Abstract: Recently data communication spread to the mobile wireless world. The complexity of medium and large speech & speaker recognition systems are beyond the memory and computational resources of the small portable devices. Moreover, the most common approach to speaker recognition today is the use of global Gaussian Mixture Models (GMM) which ignores knowledge of the underlying phonetic content of the speech, so it does not take advantage of all available information. In this paper we address the solution of these two problems by investigating the phoneme effect on speaker recognition system. We used YOHO database for speaker identification task. We found that some phonemes have strong effect on speaker identification. Segmenting the most effective phoneme for speaker recognition task from a speaker utterance and send this phoneme only through the wireless communication system will decrease the complexity of medium and speed up the authentication process though mobile communication system. We have applied different approaches on YOHO corpus, several of these approaches were able outperform previously published results on the speaker ID task. One of our approaches could achieve 0.7% error rate by using only an average segment of 4.45% of the testing utterance for recognition. 

Keywords: Speaker recognition, speaker identification, speech recognition, wireless communications. 

Design and Implementation of a Two-Phase Commit Protocol Simulator

Toufik Taibi¹, Abdelouahab Abid², Wei Jiann Lim², Yeong Fei Chiam², and Chong Ting Ng²

¹College of Information Technology, United Arab Emirates University, UAE

²Faculty of Information Technology, Multimedia University, Malaysia

Abstract: The Two-Phase Commit Protocol (2PC) is a set of rules, which guarantee that every single transaction in a distributed system is executed to its completion or none of its operations is performed. To show the effectiveness of 2PC, a generic simulator is designed and implemented to demonstrate how transactions are committed in a safe manner, and how data consistency is maintained in a distributed system with concurrent execution of randomly generated transactions.  Several possible failure cases are identified and created in the system to test its integrity, thus showing how well it responds to different failure scenarios, recovers from these failures, and maintains data consistency and integrity. The simulator was developed using Java Remote Method Invocation (RMI), which is particularly powerful in developing networking systems of such scale, as it provides easy remote method calls without the need to handle low-level socket connection.

Keywords: 2PC, transaction coordinator, transaction manager, data manager, locking manager, failure recovery, RMI. 

Received July 9, 2004; accepted December 17, 2004 

Incremental Learning of Auto-Association Multilayer Perceptrons Network

Essam Al-Daoud

Faculty of Science and Information Technology, Zarqa Private University, Jordan

Abstract: This paper introduces a new algorithm to reduce the time of updating the weights of auto-association multilayer perceptrons network. The basic idea is to modify the singular value decomposition which has been used in the batch algorithm to update the weights whenever a new row is added to the input matrix. The computation analysis and the experiments show that the new algorithm speeds up the implementation about 5-8 times.    

Keywords: Neural networks, auto-association multilayer perceptrons, singular value decomposition. 

A Novel Quantum-Inspired Evolutionary Algorithm for Multi-Sensor Image Registration

Hichem Talbi¹, Amer Draa², and Mohamed Batouche²

¹USI Emir Abdelkader, Constantine, Algeria

²Lire Laboratory, Mentouri University, Constantine, Algeria

 Abstract: In this paper, we propose a new algorithm for image registration which is a key stage in almost every computer vision system. The algorithm is inspired from both evolutionary algorithms and quantum computing fields and uses the mutual information as a measure of similarity. The proposed approach is based on some concepts and principles of quantum computing such as quantum bit and states superposition. So, the definitions of the basic genetic operations have been adapted to use the new concepts. The evaluation of each solution is performed by the computation of mutual information between the reference image and the resulting image. The process aims to maximize this mutual information in order to get the best affine transformation parameters which allow the alignment of the two images belonging to either similar or different modalities.  

Keywords: Image registration, evolutionary algorithms, mutual information, quantum computing, states’ superposition. 

Message form the Editors  

A Mobility-Aware Two-Phase Commit Protocol

Nadia Nouali^1&2, Habiba Drias², and Anne Doucet³

¹Mobile Computing Department, CERIST, Algeria

²Faculté du Génie Electrique, Université Houari Boumediene, Algeria

³LIP6 Laboratory, Université Pierre et Marie Curie, France

Abstract: The exploding activity in the telecommunication domain and the increasing emergence of portable devices are making mobile ubiquitous computing a reality. However, many challenging issues have to be faced before enabling users to take part in distributed computing while moving in an efficient and quasi-transparent manner. Many researches focus on revisiting the conventional distributed computing paradigms for use in the new environment. In this paper we propose to revisit the conventional implementation of the Two Phase Commit (2PC) protocol which is a fundamental asset of transactional technology for ensuring consistent effects of distributed transactions. We propose a new execution framework that provides an extension aware of the mobility of the hosts. The proposed Mobility-aware 2PC (M-2PC) protocol preserves the 2PC principle and the freedom of the mobile clients and servers while it minimizes the impact of unreliable wireless communication links. 

Keywords: Mobile computing, mobile transactions, mobile 2PC protocol, disconnection, mobility.