Earticle

The vertical handover decision strategy in the heterogeneous wireless networks is very challenging issue because it needs to deal with many different radio access networks and make decisions for vertical handover calls between them. Due to traffic offloading the decisions for vertical handovers to WLAN hotspots in heterogeneous wireless networks are very important because they impact the QoS of the mobile users, especially when they are using real-time services. In this paper we propose vertical handover decision algorithm from WiMAX to WLAN networks based on the user’s speed and session’s priority (non-real-time or real-time service) of the mobile nodes. We use the IEEE 802.21 standard as a layout for implementing the algorithm. The implementation of our handover algorithm avoids unnecessary vertical handover from WiMAX to WLAN in scenarios with various traffic types and speeds of the mobile nodes. The results show that the proposed algorithm improves the vertical handover latency, packet loss and average throughput of the mobile users.

In this study, we propose a flexible template-matching algorithm for word segmentation, and structural analysis of features extraction is used for character recognition in the printed Arabic text. The input text image is preprocessed by the binarization and then by morphological operations. A vector quantization of the thinned image (VQTM) is created based on the idea of a freeman chain code tracking method. In the segmentation process, 113 character templates are compared for partially/completely existence in the VQTM. A non-linear filter is applied on the segmented regions to extract the termination and bifurcation features. The spatial distribution of the extracted features and other statistical characteristics are analyzed for the verification of recognition. Experimental results show that the overall recognition rate of the three fonts: Arabic transparent, simplified Arabic and traditional Arabic is 98.63%.

Ontology matching is one of the most important challenges in the semantic web. It is a technique which is used to find the semantic correspondences between entities which are modeled in different ontologies. Despite many research efforts in ontology matching, the matching process still suffers from severe problems with respect to the quality of the matching results. Furthermore, finding the correspondences, for the most part, is very time-consuming. In this paper, we examine how a pre-processing phase can improve the results of the matching process. A pre-processing phase is added to the matchers for the analysis of input ontologies so as to detect some inappropriate patterns which are modeled by various developers. Then, refactoring operations are utilized on detected patterns for achieving assimilated ontologies. Finally, our proposed approach is tested by ASMOV (Automated Semantic Matching of Ontologies with Verification), which is one of the top matchers in OAEI (Ontology Alignment Evaluation Initiative). Experimental results show that ontologies achieved from this proposed approach are more efficient than the original unrepaired ones, with respect to standard evaluation measures.

The paper is concerned with posterior analysis of exponentiated gamma distribution for type II censored samples. The expressions for Bayes estimators and associated risks have been derived under different priors. The entropy and quadratic loss functions have been assumed for estimation. The posterior predictive distributions have been obtained and corresponding intervals have been constructed. The study aims to find out a suitable estimator of the parameter of the distribution. The findings of the study suggest that the performance of estimators under gamma prior using entropy loss function is the best.

Motorcycles generate different sound patterns under dissimilar working conditions. The generated sound pattern gives a clue of the fault. Mainly the parts of the engine that lead to change in sound are cylinder kit, crank, timing chain, and valve. The parts of the exhaust system that change sound under fault are muffler and silencer. In this study, we analyze the sound signals produced by motorcycles to locate the faults in subsystems. The work proceeds in three stages, the first stage detects the fault, the second stage identifies the faulty subsystem and finally the third stage locates the fault. The overall classification accuracy of the first stage is 0.8019. The work finds interesting applications in troubleshooting of machinery, electronic gadgets, musical instruments and the like.

The use of wireless devices are flooding the network, thus giving rise to extensive data transmission. One of the main concerns is how to dictate the buffering of data so that throughput fairness can be achieved, specifically in the multihop wireless networks. The technique of buffering has to be based on the scheduling algorithms. Several studies on scheduling algorithms as a part of congestion control have been carried out, such as by Shagdar, Nakagawa and Zhang [1], Izumikawa, Ishikawa, and Sugiyama [2], and Giang and Nakagawa [3]. The Round Robin (RR) scheme is considerably simpler than other known schemes for achieving throughput fairness in multihop wireless networks. As is RR scheme, the main cause of concern is the delay that is been caused by high volumes of workloads at the wireless source nodes. It is therefore the purpose of this paper to enhance the network performance in wireless LANs by improving the fairness index and average end-to-end delay the through the scheme identified as Proposed Packet Reverse Function.

Distributed Systems remained one of the most recent development fields in computing research. The parallel applications development faced enormous hindrance in QoS delivery due to resource hungry queuing models and complex memory patterns. Being a collection of multiple autonomous systems, a distributed system's efficiency lies in best coordination of its middle ware and coordinating modular layers. The concurrency is maintained by implementing Integrity constraint rules. The paper assesses various coherence addressing schemes for QoS delivery in Distributed Network environment.

The World Wide Web (WWW) comprises enormous websites located around the world, and it is the cheapest source to publish information that instantly becomes accessible across the globe. The information available on the Internet is invariably increasing on the daily basis, which in turn is resulting in serious challenges for the researchers to retrieve the relevant information from huge bulk of data. The precious time of researchers and scientists goes wasted as they have to sift through massive amount of irrelevant and unnecessary material returned by the conventional search engines. Due to this fact, the task of searching focused and relevant material has become a tedious activity in the information retrieval process over the Internet. This very unfocused and nonspecific type of the Internet surfing often results in overlooking the important contents due to monotonous and sloppy structure of the retrieved information, in addition to the tiresomeness and grimness it causes to the end user. In this paper, we present a framework for multi-agent based search engine tool that can help the researchers to find their desired information in an efficient way and with the minimal pointer clicks. Through this methodology, the researchers would be able to obtain a summarized report along with the search details that closely match to the supplied search phrases. The same summary report can also be generated based on the research topics inscribed in the researchers’ profile or based on the history of their previous WWW usage.

This paper presents the concepts of test case based approach for the development of software systems. A variety of software development approaches are presented wherein they share some common methodology stages wherein testing plays a vital role for the success of the product. Software testing provides an objective, independent view of the software to allow the end-user to appreciate and understand the risks of software implementation. Examples of test cases for developed software have been presented.

This paper deals with the optimization of a cantilever beam submitted to its own weight. In a first approach, we consider that the beam section can be equal to two values and we are looking for the section changing location, which minimizes the deflection. We propose an analytical model with an experimental validation that will allow us to optimize the shape of the beam. Then, we develop a numerical code based on a genetic algorithm that we validate on this case. In a last section, we use our numerical optimization code to find the best shape of the beam, where the section can now take any values in a given range, to minimize its deflection. These two study cases can serve as reference case to validate numerical approach for automatic structure optimization.

The necessity to utilize the usage of the robot cannot be denied since there are a lot of natural disasters occur everywhere around the world. The robot that can be used in this situation may be a remotely controlled by human or moves autonomously. Hexapod robot is one of the robots used in this situation because of its stability and flexibility during the motion on any type of surface. Hexapod robot is a robot that has six legs to walk or move. Since the robot has many legs, the robot is easily programmed to move around because it can be configured to many types of gait such as alternating tripod, quadruped and crawl. There are various designs of hexapod with certain function and advantages. In this research, a hexapod robot with manoeuvrable wheel is designed and developed. The purpose of the hexapod robot with manoeuvrable wheel is to ease the movement either on the flat surface or on the inclined surface. On the flat surface, the robot will move using the manoeuvrable wheel while on incline surface, the robot will climb using its legs. The decisions for the robot to use either wheel or legs are based on the sensory devices and algorithm develops at the controller attached to the robot.

Software architecture is a standard and essential part of system development. The knowledge produced and consumed during this process needs to be shared and reused among different stakeholders. Therefore, software architecture knowledge (AK) needs to be managed for improving the architectural capabilities. ADUAK (Architectural Development using Architectural Knowledge) model has been developed to support a framework for capturing and using architectural knowledge to improve the architecture design process. ADUAK guides the architect in selecting the most appropriate architecture, where the interactions between quality attributes, tactics should be analyzed and quantified and the results should be considered for the quality driven architectural design process. Ontology based AK tool is needed, because ontologies are used to combine the real world domain information and software architectural knowledge from various experts, to maintain up – to – date documentation that evolves over time. The primary focus of ADUAK is to acquire knowledge for the fuzzy based evaluation of the architectures of the system using ontologies. It is needed because the architecture represents an enormous risk in a development project. Making bad architectural designs may substantially slow down the system and even lead to failure. The quantitative impact of incorporating the quality in the software architectures is then calculated through a fuzzy based approach for the set of design alternatives. The paper aims to bring the contribution of ADUAK model for the fuzzy based quantitative evaluation of architectures with the help of architectural knowledge through a suitable case study.