Mohammad Bsoul

Enhanced Fast Spread Replication strategy for Data Grid

Data replication is used in Data Grid to enhance data availability and fault tolerance. However, replication should be used wisely because the storage size of each node reside on the Data Grid is limited. Thus, the node must accommodate only the important replicas. In this paper, a dynamic replication strategy that takes into account the number and frequency of requests, the size of the replica, and the last time the replica was requested is proposed. This strategy is an enhanced version of Fast Spread replication strategy. The simulation results show that the new proposed strategy attained better performance than Fast Spread with Least Recently Used (LRU) and Fast Spread with Least Frequently Used (LFU) in terms of total response time and total bandwidth consumption.

An Energy-Efficient Threshold-Based Clustering Protocol for Wireless Sensor Networks

Energy-constrained wireless sensor networks (WSNs) have been deployed widely for monitoring and surveillance purposes. Since sensor nodes (SNs) have significant power constraints (battery life), energy-efficient protocols must be employed to prolong the network lifetime. In this paper, we propose an energy-efficient protocol which provides a new way of creating distributed clusters. This protocol is a modified version of Low Energy Adaptive Clustering Hierarchy (LEACH) protocol. The experimental results show that our protocol that takes into account both the residual energy at each SN and the distance between the SNs outperforms LEACH protocol in terms of first node death time and average residual energy.

A threshold-based dynamic data replication strategy

Data replication is the creation and maintenance of multiple copies of the same data. Replication is used in Data Grid to enhance data availability and fault tolerance. One of the main objectives of replication strategies is reducing response time and bandwidth consumption. In this paper, a dynamic replication strategy that is based on Fast Spread but superior to it in terms of total response time and total bandwidth consumption is proposed. This is achieved by storing only the important replicas on the storage of the node. The main idea of this strategy is using a threshold to determine if the requested replica needs to be copied to the node. The simulation results show that the proposed strategy achieved better performance compared with Fast Spread with Least Recently Used (LRU), and Fast Spread with Least Frequently Used (LFU).

Models for using internet technology to support flexible e-learning

Information and Communication Technologies (ICTs) have been diffused in higher education slower than it has been expected. Especially for developing countries, using ICT in the most efficient and effective ways has crucial importance for the sustainable development and effective use of resources. This paper presents a theory-based design framework for e-learning that emphasises the transformative interaction between technology readiness and innovativeness. This study is a theory-building investigation and offers a theory-into-practice framework that characterises the implications of innovativeness and motivation in the recent trend of the higher education use of internet technology to facilitate its own operations, in the form of e-learning.

A Round-based Data Replication Strategy

Data Grid allows many organizations to share data across large geographical area. The idea behind data replication is to store copies of the same file at different locations. Therefore, if a copy at a location is lost or not available, it can be brought from another location. Additionally, data replication results in a reduced time and bandwidth because of bringing the file from a closer location. However, the files that need to be replicated have to be selected wisely. In this paper, a round-based data replication strategy is proposed to select the most appropriate files for replication at the end of each round based on a number of factors. The proposed strategy is based on Popular File Replicate First (PFRF) strategy, and it overcomes the drawbacks of PFRF. The simulation results show that the proposed strategy yields better performance in terms of average file delay per request, average file bandwidth consumption per request, and percentage of files found.

A study on e-commerce security in Jordan

The internet and all other kinds of networks have changed our way of life in general and the way to do business in particular and, as a result, many companies nowadays are conducting and transferring their businesses online. However, some of them are not successful. Until now, the majority of companies and customers have not been certain that doing business online is secure and protects them from any illegal activities, since there is no physical interaction (face-to-face) between customers and companies and every business will be cautious about payment methods, the quality and quantity of products or services and the delivery system, among many others. This paper attempts to evaluate whether security issues are the major obstacles to the growth of e-commerce in Jordan. A survey conducted for the study reveals that security issues are major barriers to internet banking and e-commerce activities among consumers.

A dynamic replication strategy based on categorization for Data Grid

Data Replication is copying the data from a certain location to another location. Replication is used in Data Grid to have two or more copies of the same data at different locations. In this paper, a Category-based dynamic replication strategy (CDRS) is proposed. The strategy takes into account that the replicas exist on a node belong to different categories. Each of these categories is given a value that determines its importance for the node. When the nodes storage is full, the node starts to store only the replicas that belong to the category with the highest value. The results of the simulations show that the new proposed strategy achieved better performance than Plain Caching and Fast Spread strategies in terms of total transit time and total bandwidth consumption.

Optimal spectrum utilisation in cognitive network using combined spectrum sharing approach: overlay, underlay and trading

Cognitive radio technology enables unlicensed users (secondary users, SUs) to access the unused spectrum. In the literature, there are three spectrum sharing paradigms that enable SUs to access the licensed spectrum. These access techniques include underlay, overlay and spectrum trading, and have their own drawbacks. To combat these drawbacks, we propose a new approach for each of them and merge them into one combined system. Our overlay scheme provides quick access to the unused spectrum. We propose a new cooperative sensing protocol to reduce the likelihood of interfering with PUs. In order to enable SUs for transmitting simultaneously with PUs, we suggest using our underlay scheme. Our trading scheme allows PUs to trade the unused spectrum for the SUs that require better quality of service. The new combined scheme increases the size of spectrum in the cognitive network. Simulation results show the ability of the new scheme to serve extra traffic.

An approach to automatically enforce object-oriented constraints

This paper presents an approach to automatically enforce object-oriented constraints during incremental C++ code changes. The approach is realised as a tool to keep track on code changes and to notify developers with violations of predefined OO constraints. The OO constraints under consideration are taken from object-oriented design metrics. The object-oriented metrics mainly cover class size, coupling between classes, number of subclasses and inheritance tree. The goal of this work is to help designers to monitor design during incremental code changes. Object-oriented design metrics are automatically extracted from source code. The extracted metrics are used by designers to define the constraints. The tool supports defining and managing these OO constraints. After a code change is committed, design changes are identified and predefined constraints are checked for possible violations. The evaluation of the tool shows that it helps in detecting violations of design constraints, and it saves time and efforts of developers.

A framework for replication in Data Grid

Data replication is the creation and maintenance of multiple copies of the same data. Replication is used in Data Grid to enhance data availability and fault tolerance. In this paper, a framework for replication in the Data Grid is proposed. The framework is considered an environment that can be used to evaluate the performance of different replication strategies. An event-driven simulator written in Java is used to evaluate the performance of three replication strategies based on the new proposed framework. These strategies are No Replication, Plain Caching, and Fast Spread. The simulation results show that Plain Caching strategy achieved the best performance, while No Replication strategy achieved the worst performance in terms of number of requests served locally (NORSL).