A Heterogeneous Framework for the Global Parallelisation of Genetic Algorithms

Mohammad Hamdan

Department of Computer Science, Yarmouk University, Jordan

Abstract: There is a big need for the parallelisation of genetic algorithms.  In this paper, a heterogeneous framework for the global parallelisation of genetic algorithms is presented. The framework uses a static all-worker parallel programming paradigm based on collective communication. It follows the single program multiple data parallel programming model. It utilises the power of parallel machines by allowing multiple crossover and mutation operators being used within a single genetic algorithm.  This mixture of operators  can  be  applied  to  the  strings  of  a  population  in  parallel  without  changes  to the  canonical  sequential  genetic  algorithm. These features help the parallel genetic algorithm in exploiting the search space efficiently and thoroughly when compared to the sequential genetic algorithm. The framework is instantiated with specific parameters to solve an NP-hard problem, the asymmetric travelling salesman problem.  The results  for the  parallel  genetic  algorithm  are very  good  in  terms  of  solution  quality. Also very good speedup and scalability results were achieved on the parallel machine.

Keywords: Genetic algorithms, parallel processing, parallel genetic algorithms, crossover, mutation, TSP.

Received November 14, 2006; accepted February 28, 2007

Self Ranking and Evaluation Approach for 

Focused Crawler Based on Multi-Agent System

Hesham Ali

 Computers Engineering and Systems Department, Mansoura University, Egypt

Abstract: The need of better way of retrieving information and dealing with the increasing complexity and volume of information for users is an important research theme. Retrieving information from the www via search engine may be deliberate as the most significant one. Most of the recent efforts that had been done in this area suggest a better solution for general-purpose search engine limitations. That leads to a new generation of search engines called vertical-search engines. However, all current focused crawlers; (crucial component within vertical search engine) crawling strategies introduced high penalties as they consume network bandwidth and resources of hosting servers. This paper introduces a new approach for focused crawling that integrates evidence from both focused crawling and intelligent multi-agent technology. It will help in distributing the computation among data sites, hence overcoming the drawbacks of traditional approaches. We evaluate its performance compared to the client/server-based computation model from perspectives of amount of data transfer and execution time through both simulation and analytical study. The results achieved from the experiments confirm efficiency of the proposed approach. Both of execution time and traffic are reduced in the case of mobile agent compared with client/server model (i.e., eliminating the bottleneck, and overhead problem at crawler site). Furthermore, such combination will also simplify the design and implementation of focused crawlers.

Keywords: Search engine, vertical search engine, focused crawler, mobile agents, multi-agents systems.

Received December 12, 2006; accepted February 27, 2007

Effect of Filter Size on Fusion Function in Information Retrieval

Nagammapudhur Gopalan ¹ and Krishnan Batri ²

¹Department of Computer Applications, National Institute of Technology, India

²Department of Computer Science and Engineering, National Institute of Technology, India

Abstract: An attempt to detach the worst performing schemes for improving the effectiveness of the information retrieval system, which combines the multiple sources of evidence, has been presented in this paper. The disturbances caused by the ill performing retrieval schemes are studied by using the concept of filter. The size of the filter is altered to examine the efficiency of the retrieval system. The experiments are conducted over the three-benchmark test collections viz., ADI, CISI and MED. The results indicate that, the efficiency of the retrieval system varies with the filter size and the maximum improvement in performance is achieved only at particular filter size, which is different for various fusion functions.

Keywords: Information retrieval, fusion, filter, overlap, and precision.

Received December 6, 2006; accepted February 21, 2007

Mobility Prediction Based Resource Reservation for Handoff in Multimedia Wireless Cellular Networks

Maher Al-Sanabani, Shamala Subramaniam, Mohamed Othman, and Zuriati Zukarnain

 Department of Communication Technology and Networks, University Putra Malaysia, Malaysia

Abstract: In this paper, a mobility predictive based resource (bandwidth) reservation is proposed to provide flexible usage of limited resource in wireless cellular networks. Currently, multimedia communications is urgently expected in wireless networks. That as there is more and more high speed applications that emerge for wireless networks. One of the most important and complicated issues is the Quality of Service (QoS) in next wireless networks. In other words, the problem to maintain the playing continuity of multimedia streams during handoff is hard for solution. Hence, in this paper, the scheme is proposed to provide high accurate prediction of next crossing cell that Mobile Terminal is going to, in order to avoid too early or over reservation resulting in a waste of resources. The amount of bandwidth to be reserved is dynamically adjusted according to the current position and extrapolated direction of Mobile Terminal. An admission control scheme is also considered to further guarantee the QoS of real time traffic. The performance of system is evaluated through discrete event simulation of realistic wireless cellular environment. Simulation results show that the proposed scheme as compared to the existing schemes is efficient to reduce the New Call Blocking Probability and the Handoff Call Dropping Probability of real time traffic. In addition, it is efficient to reduce the number of terminated ongoing calls of non-real time traffic and the cancels reservation that increase the system bandwidth utilization.

Keywords: Wireless cellular networks, mobility prediction, resource reservation, handoff and quality of service.

Received October 12, 2006; accepted March 25, 2007

An Efficient Region-Based Approach for Object Recognition and Retrieval Based on Mathematical Morphology and Correlation Coefficient

Jehad Alnihoud

Department of Computer Science, Al-al Bayt University, Jordan

Abstract: In this paper, a new technique based on slicing the images to equally sub-areas, then applying the density slicing to the color histogram of these areas combined with the color pair technique is presented as a  filtration phase based on the color features of images. This allows dramatic reduction in the candidate sets of images, which needs to be proceed through the time-consuming process of shape feature extraction and comparison algorithms. After that, shape recognition method is proposed as a higher level phase in the proposed system. The proposed approach for shape-based retrieval relies on detecting the edges of the objects, using laplacian of gaussian, in the image query as well as the set of filtered images from the proceeding layer of color approach. Next, the morphological techniques, using dilate and erosion are applied, in order to solidify the objects within the image and to increase the chance of correlation coefficient to be used as means of similarity between images. Furthermore, transformation of objects is applied to overcome the rotation based problem. The experimental results show that the proposed approach is fast, efficient, and feasible.

Keywords: Morphological operations, density slicing, color histogram, correlation coefficient.

Received September 27, 2006; accepted February 15, 2007

Full Text

From e-Manufacturing to M-Manufacturing

Faiza Bouchoul and Mohamed Mostefai

 Laboratoire d’Automatique de Setif-LAS- Automation Lab. of Setif, Ferhat Abbas Uni., Algeria

Abstract: This paper studies the impact of wireless technologies on enterprises. A multitude of new paradigms and new software technologies have emerged from the web. E-business and e-manufacturing have really transformed concepts and practices in enterprises. Wireless technologies added new possibilities for these technologies, by this work we propose m-manufacturing as a component of e-manufacturing when practiced in mobile environment, then compare e-manufacturing to m-manufacturing. We applied our proposed approach to model m-maintenance of spare parts. Combination of mobile agent technology and fault-tolerant principles has given an appropriate global solution tom m-maintenance issues

Keywords: Wireless technologies, mobile enterprise, m-manufacturing, m-maintenance, mobile agents, fault-tolerance

Received May 31, 2006; accepted December 27, 2006

Performance Analyses of Fast Frequency Hopping Spread Spectrum and Jamming Systems

Abid Yahya¹, Othman Sidek1, and Junita Mohamad-Saleh²

¹Collaborative MicroElectronic Design Excellence Center, Universiti Sains Malaysia, Malaysia

²School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Malaysia

Abstract: As technology becomes increasingly able to meet the requirements, interest in faster, noncoherent, frequency hopping rates to reduce the jamming of communication has heightened. The focus of this paper is on the performance of the fast frequency hopping spread spectrum system operating in the presence of partial band noise jamming. In this paper we consider a communication system that transmits binary data sequence or M frequency shift keying over a channel. With non-coherent detection, the MFSK tones on a given hop must be separated in frequency by an integer multiple of chip rate to provide orthogonality. The worst case partial-band noise jammer chooses fraction () to maximize the bit error probability (Pb) for a given M and signal to noise ratio. It has been observed from the simulation results that increases with K, illustrating the effectiveness of worst-case jamming () against FH/MFSK signals at typical operating points. It may be noted that   decreases as Eb/NJ gets larger. <!--[if !vml]--><!--[endif]--> <!--[if !vml]--><!--[endif]--> <!--[if !vml]--><!--[endif]-->

Keywords: Frequency hopping spread spectrum, interference, partial band noise jamming.

Received August 23, 2006; accepted February 19, 2007

Strategic Planning for e-Development in Developing Countries

Abdel Nasser Zaied

College of Graduate Studies, Arabian Gulf University, Bahrain

Abstract: One of the most persistent criticisms of open markets and free trade is that they increase the gap between developed and developing countries. The rapid emergence of the internet economy is giving this argument new impetus and is increasing focus on the digital divide and e-development to reduce the gap between “information rich” and “information poor” countries. Information and Communication Technology (ICT) is widely recognized as a potentially powerful tool to minimize this gap. ICT can provide a great opportunity for developing countries to leapfrog stages of economic development. A strategic management approach to ICT is therefore necessary in providing national guidelines on how ICT can be harnessed by developing countries to increase their technological capabilities towards e-development.This  study  proposes  a framework  that  aimed  at   facilitating  the  process  of  creating  and  implementing   ICT   strategies. This framework which comprises three phases is a step-by-step methodology that can help the developing countries to establish their own ICT strategies. It needs further studies to complement with countries mission based on their resources and situations.

Keywords: Strategic planning, e-development.