International Journal of Computer Techniques

7-13

Authors: Comparing the Performance of Real-Time Applications based on IPv4 and IPv6Networks

With the expansion of Internet, the current protocol address space (IPv4) is faced with a shortage and the new generation Internet (IPv6) is raised in order to solve this problem. Also with increasing interest of users in real-time and multimedia applications, the Internet and how to implement these applications to improve the quality of service (QoS) has become a significant challenge. In this paper, a network with both IPv4 and IPv6 protocols is simulated by using OPNET Modeler and implementation of QoS is tested on it. Packet loss, end-to-end delay and jitter were evaluated as network performance metrics. The results showed that satisfying the needs of multimedia applications on IPv6 are slightly weaker than IPv4, but the benefits have evolved more and more and the difference is negligible. Also according to the methods used in terms of this study, the combination of DiffServ and MPLS QoS implementation is the best option for both Internet Protocol versions. Keywords—IPv4, IPv6, real-time applications, Quality of Service (QoS), BE, DiffServ, MPLS

19-27

Authors: Prof.Galal Ali Hassaan

Quarter-car model is in use for years to study the car dynamics. The objection of this paper is to examine the dynamics of a car passing a circular hump for sake maintaining ride comfort for the passengers. Passive suspension elements are considered with suspension damping coefficient in the range 1 to 15 kNs/m. Car speed in the range 5 to 25 km/h is considered when passing the hump. Important phenomenon evolved from the analysis of the car dynamics which is performed using MATLAB. The mathematical model of the quarter-car model is derived in the state form and the dynamics are evaluated in terms of the sprung mass displacement and acceleration. The effect of suspension damping and car speed on the sprung-mass displacement and acceleration is examined. The study shows that for ride comfort the car speed has not to exceed 6.75 km/h when passing a circular hump depending on the suspension damping. . Keywords —Car dynamics , quarter model , Passive suspension system , Standard humps , Ride comfort.