The World of Computer Science and Information Technology Journal

7

Authors: Nasim Matar

This paper presents a new approach for setting criteria towards evaluating e-portfolio use within educational context. The urge for considering e-portfolio systems in current educational context is becoming more vivid, as many systems are developed to address the need for gathering artifact used within educational context. The wide development of web 2.0 technologies has given the opportunities for many e-portfolio systems to emerge and provide different services and functionalities that are used for different aims and objectives that are not related to educational use. The need for differentiating the offered services and functionalities is becoming necessity as different educational establishments have been found using e-portfolios that are not designed for educational purposes. This study, managed to present six different e-portfolio systems that are found suitable for educational purposes, and have set the criteria for differentiations that will present the most suitable e-portfolio system within educational context. Those same criteria can be used with any newly designed e-portfolio system, and they can be looked at as a guide map for selecting the most appropriate e-portfolio system. Keywords-component; e-portfolio; educational systems; evaluation; Multi Adaptive Educational Hypermedia.

10

Authors: Ghassan Samara, Mohammad Rasmi

The rapid development of wireless communication networks in recent years has made vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communications possible in mobile ad hoc networks (MANETs). It has also led to the development of a new technology called vehicular ad hoc network (VANET), which aims to achieve road safety, infotainment, and a comfortable driving experience. It can support safety systems designed to avoid road accidents in two ways: 1) periodic transmissions (beacon) from all vehicles that inform neighbors about their current status, and 2) dissemination of emergency messages to warn other vehicles to avoid the danger. The intent of the research is to propose an efficient safety system for VANET by designing communication protocols and techniques to provide the means for successful transmission of safety-related information. Therefore, three protocols based on power control, contention, and position-based mechanisms are proposed to shape data traffic, such that messages are received with high probability and reliability where they are relevant. First, a method Coded Repetition Neighbor Table (CRNT) is proposed in [1], which aims to increase the network awareness to enable the network vehicles to know about current network situations and detect other vehicle movements. Second, a method called Particle swarm optimization Contention Based Broadcast (PCBB) is proposed in [2] for fast and effective dissemination of emergency messages within a geographical area to distribute the emergency message. Third, a method called Particle swarm optimization Beacon Power Control (PBPC) is proposed in [3], which aims to decrease the packet collision resulting from periodic messages leading to the control of the load on the channel while ensuring a high probability of message reception within the safety distance of the sender vehicle. Using the latest version of Matlab simulator, the merits of all the approaches, as well as of their synergies are demonstrated. Simulation results show that PBPC is capable of improving the reception rates of beacon messages and increasing the probability of reception of emergency messages over a wide range of distances between sender and receivers. PCBB enhances the delivery of the emergency information to all nodes located in a geographical area by more than 70%. Furthermore, it enables the emergency message to reach greater distances, thus benefiting the incoming vehicles receiving the important information. When PCBB is used in combination with CRNT and PBPC, the dissemination efficiency and delay are considerably improved. Finally, PBPC is capable of improving the channel performance by controlling the channel load resulting from the beacon messages, reducing packet collision by 50%. Keywords-VANET; Safety System; PBPC; CRNT; PCBB.