Thossaporn Kamolphiwong

A design framework of interactive distance learning in distributed systems

In this paper, we present a design framework of interactive distance leaning (IDL) in distributed system environment. In this design framework, interactive distance learning (IDL) system is based on Java technology: Jini technology and Java Media Framework (JMF). Using Java language, a developed system is a platform independent both in software, e.g. operating systems (OS), and hardware, e.g. computer and mobile devices. Any target systems that can run Java Virtual Machine (JVM) are able to run our IDL. In addition, it also gives us a low complexity of implementation. To work with any firewalls in a network, we have proposed an IDL gateway which allows us to not only solve the packet blocking problem but also to solve the multicast address problem. Moreover, the framework supports fully distributed services. For example service and database engines could be in separated physical location, e.g. video server and database server. This allows system scale up easily with small limited conditions. We have demonstrated our prototype software to show that it is working effectively.

Performance evaluation of IPv4/IPv6 transition mechanisms: IPv4-in-IPv6 tunneling techniques

Exhaustion of IPv4 address space is highly aware for most internet players, not only Internet Service Providers (ISPs), but also Telco and Content Providers. A number of IPv4/IPv6 migration/transition tools and mechanisms have been proposed, deployed/implemented world-wide. To make IPv4 networks be able to connect to IPv6 world, 4over6, DS-lite, and 4rd seems to be the most attractive solution according to their features and functions benefits. Beside such benefits, in this paper, we investigate their performance in terms of delay time, and reliability in both inter and intra-communications. Comparison results and analysis of these 3 solutions will be given. We conclude that these figures will provide the factors of scalability and quality-of-service (QoS).

Interactive examination management system

To handle several online examination settings, a web-based application test management software, namely interactive examination management system (iEMS), is proposed in this paper. The outstanding points of the proposed system are its good architecture designs, ease of uses, rich features, flexibilities and extensibilities. Seven standard types of questions are supported including multiple-choice, true/false, matching, ordering, fill-in the blank, short answer and essay questions. Except the essay questions, the iEMS can automatically grade the answers. Several design issues are discussed such as the graphic user interface, the special control character of the system and the flow of controls used in such systems. The student feedbacks on the iEMS are positive. That is, the simple graphic user interface is easy to learn; the interactive feature of the iEMS allows the students to get the results very fast; more tests can be given and automatically graded which results in a high attendant rate.

Performance of intra and inter communications of IPv4-in-IPv6 tunneling mechanisms

In order to reach the customers thoroughly, internet contents need to support both IPv4 and IPv6. In this case, ISPs should provide their customers with IPv4 and IPv6 access seriously until the IPv4 is disabled eventually. Each transition solution needs to concern not only high working performance but also network supporting in the future. This paper investigates the performance of various transition schemes; IPv4 Residual Deployment across IPv6-Service networks (4rd), 4over6, Lightweight 4over6 (Iw4over6) and Enhancement of Lightweight 4over6 (elw4over6). Computer simulations are divided into two scenarios: intranet (intra-communication) and internet (inter-communication) based on the following performance metrics: CPU utilization, HTTP traffic received, HTTP traffic lost and HTTP object response time. We have found that elw4over6 is the best one for the networks that require flexibility of IP address allocation and providing good quality of IPv4 connectivity.

QoS Aware for Peer Selection on P2P Streaming Services

Internet Protocol-based Television (IPTV) is a mechanism for transporting a stream of video content over a network that uses the IP networking protocol. Compared to the traditional TV system, IPTV is offers much better features and services. However, most of IPTV services are based on a client-server approach that has some limitations and may not be sufficient to support the rapidly increasing demand. So the Peer-to-Peer (P2P) model, with its potential scalability and the ease of operation, has been considered as an alternative solution. Providing the quality video content in P2P IPTV services, it is agreed that to have good national selection algorithm that can improve service quality. Good peers can vastly influence the QoS of the application running on those peers. In this research work, we propose peer selection with QoS aware for P2P IPTV service by evaluating quality of video content delivered using an end-to-end measuring approach. The video time delay is calculated from buffer map of each peer to reflect the target peer quality in the system perspective. Also, in the new joining peer perspective each peer was calculated by paying attention to the path from each peer to the new joining peer. With this algorithm, the real proper and good servers can be discovered to provide a good service to a new joining peer. We have shown that our proposed scheme performs better results in terms of delay time.

Enhanced Context Searching Based on Structured P2P

Most of context aware systems are based on client-server model which has some limitations, e.g. a bottle neck problem, single point of failure. The most disadvantage of client-server model is when all nodes need to update their context information frequently and quickly; it will cause massive information flooding in a system. By applying P2P model to context aware system, this problem can be reduced. However, it will create other problems, e.g. context searching will take more time when a number of hops are large, ontology distribution issue, problems of storing ontology and reasoning process. In this paper, we have proposed MF-P2P (Multi Finger P2P Table) which can reduce a context searching time in P2P model. Our design is based on Chord mechanism. By distributing processes to peers, we have shown that the system can perform a fast searching on high complexity of ontology and context.

NAT-PT with multicast

This work investigates Network Address Translation – Protocol Translation (NAT-PT) as an IPv4/IPv6 transition technique. NAT-PT is adequate for unicast communication, however, there is no provision for multicast address mapping. This paper presents a solution to improve NAT-PT by adding support for multicast. As a result, NAT-PT can provide multicast address translation, and applications using multicast can interoperate between IPv4 and IPv6. An application level gateway (ALG) for the Session Advertisement Protocol (SAP) is added to perform and announce group address mapping.