Yao-Chung Chang

Architecture design and performance evaluation of RFID object tracking systems

The network architecture of an RFID system affects the operating performance and scalability of the entire system. The related researches about RFID system could be made easier as the bridge-based and the gateway-based network architecture. This study considers a scenario for an RFID object tracking system designs a hierarchical RFID network system and evaluates the operating performance of different RFID system architectures. The results of performance evaluations demonstrate that the proposed hierarchical RFID network architecture reduces the network and database system loading by 41.8% and 83.2%, respectively. The operation of RFID object tracking over the hierarchical network architecture is indicated to be highly efficient and scalable.

All-IP convergent communications over open service architecture

The application of IP (Internet Protocol) technology in the information and communications industry is a major global trend. A highly efficient service architecture, enabling technologies and advanced applications are critical to rapid multimedia services in an all-IP network environment. In this study, an all-IP service platform based on open service architecture (OSA) was developed to support a set of standard interfaces and applications. The all-IP network environment was integrated using a network-processor-based IPv4/IPv6 translator and a mobile router (MR) supporting IP network mobility. The feasibility of the open service platform for all-IP network environments and of the designed application programming interfaces was investigated using three applications, e-commerce, video-on-demand and on-line gaming. The performance analysis demonstrates that when the number of users was increased from 1 to 80, the system throughput increased from 10.5 Mbps to 60.5 Mbps; the average response time increased from approximately 1 ms to 10.5 ms, and the delay time increased from 0.1 ms to 1 ms.

Dynamic software update model for remote entity management of machine-to-machine service capability

Daily life applications of machine-to-machine (M2M) communication are constantly increasing. Typically, M2M communication systems comprise numerous small, cheap and autonomous devices that communicate with each other while monitoring environmental conditions. After their deployment, however, remote entity management of a node is still needed for firmware or software updates required for bug fixes, functional changes or other maintenance. Therefore implementing remote entity management for M2M service capability in third generation partnership project machine-type-communication is a major challenge. Previous works have attempted to reduce traffic by updating only the software changes in the M2M device. However, the device must still reboot after a software update. Rebooting the device is costly since the previous runtime states are lost. The devices expend time and bandwidth when synchronising with other nodes and when rebuilding the routing table. Hence, the dynamic software update model (DSUM) proposed in this study is designed to enable remote entity management for M2M. A dynamic software update programming model and a prototype implementation for M2M service capability are also presented. By allowing M2M service capabilities to update the software without rebooting the node, the DSUM preserves precious runtime states. The tests in this study showed that software updating required only 88 clock cycles. This framework not only enables dynamic replacement of remote entity management functionalities at runtime, it also reduces power consumption by avoiding the need to rebuild the network topology for devices in an M2M communication network.

Efficient changes and variability bandwidth allocation for VBR media streams

Recently, the Internet bandwidth has increased rapidly. Currently available network traffic includes not only text but also graphics, such as JPEG and GIF images. Many multimedia applications are emerging, such as video on demand (VoD) and distance learning. These services involve complicated network connections between servers and clients. To simplify this system, we propose an effective and efficient traffic-smoothing algorithm, which is called ECVBA (Efficient Changes and Variability Bandwidth Allocation). This algorithm not only minimizes the peak rate of a stream but also increases the likelihood of successful variable bit-rate (VBR) stream transmission. The main benefit is that this algorithm can immediately release bandwidth to other demanding sites in the network.

Bluetooth Scatternet Using an Ad Hoc Bridge Node Routing Protocol for Outdoor Distance Education

In recent years, the prevalence of Internet and wireless technology has promoted mobile communications as a major research area. For the future distance education purposes (Instructional Technology Council), to be able to access the course materials anytime and everywhere will become a key issue. Especially when students are out of classroom and are within a museum or a field investigation process, using Ad Hoc mechanism to access the real time brief or introduction can definitely improve their learning interests greatly. One of the topics is IEEE802.11, which includes the IDEA GROUP PUBLISHING This paper appears in the publication, Future Directions in Distance Learning and Communication Technologies edited by Timothy Shih

Mobile IPv6 network: implementation and application

Recently, the world has become increasingly mobile, and people have started communicating by wireless networking. Mobile IPv6 enables mobile users to communicate with each other while moving. In this study, a mobile IPv6 network was implemented by the IEEE 802. 11 specification, and its performance was analyzed using TCP and UDP applications. The experimental results indicate that throughput stabilized for UDP applications after about 6-14 seconds. However, TCP applications were found to stabilize throughput in 10-20 seconds. The evaluation results reveal that TCP applications perform less well in mobile IPv6 networking than UDP applications.

OSA-based service platform for all-IPv6 network environments

The use of IP (Internet protocol) technology in the information and communications industry constitutes a major global trend. A highly efficient service architecture, enabling technologies and advanced applications are essential to rapid multimedia services in an all-IPv6 network environment. This work presents an all-IPv6 service platform based on open service architecture (OSA) to support a set of standard interfaces and applications. The all-IPv6 network environment was integrated using a network-processor-based IPv4/IPv6 translator and a mobile router (MR) supported IPv6 network mobility. The feasibility of the open service platform for all-IPv6 network environments and of the designed application programming interfaces was examined using three applications: e-commerce, video-on-demand, and on-line gaming. The performance analysis indicates that the system throughput increased from 10.5 to 60.5 Mb/s as the number of users increased from 1 to 80; the mean response time increased from approximately 1 to 10.5 ms, and the delay time increased from 0.1 to 1 ms.

Embedded worldwide interoperability for microwave access-based vehicular router for telematics computing

This study proposes a novel embedded worldwide interoperability for microwave access (WiMAX)-based vehicular router, with a network mobility architecture, that promotes the Telematics services for ubiquitous/pervasive computing environment anytime and anywhere. Each Telematics user processes the handoff procedure with the mobile Internet protocol mechanism. Hence, the proposed WiMAX-based vehicular router can process multiple Telematics users for handoff procedures simultaneously. This study explores and analyses network performances in terms of packet loss, round-trip time (RTT) and handoff latency. The embedded WiMAX-based vehicular router has a packet loss about 36% lower, and average RTT is approximately 34% lower than the traditional wireless fidelity-based vehicular router. The handoff latency analysis indicates that the embedded WiMAX vehicular router has better performance using the mobile network with the embedded router and more than two Telematics users.

MPLS VPN in cellular mobile IPv6 architectures

Due to the prevalence of Internet and mobile communications, people sending messages through Internet has concentrated on security and encryption regarding data transmission. The VPN (virtual private network) is the way to keep personal data secure by sending data through the public network. Following the rapid growth of the network and the decrease of IPv4 network addresses, the Internet Engineering Task Force (IETF) has initiated the promotion of next generation IP (IPv6) instead of the current IPv4. IPv6 supports the mobility and security of mobile communication environments. Since the VPN currently does not support cellular mobile IPv6, the goal of this paper is to construct a MPLS VPN framework in the cellular mobile IPv6 (CMIv6) environment, and use the IPSEC defined by the IETF to keep the security and integrity of data transmission for future mobile communication systems.

Vehicular Cloud Serving Systems with Software-Defined Networking

This work proposes an SDN architecture that helps cloud customers receive highly efficient services in a vehicular cloud serving system. An application called SDNBroker is designed herein and superposed on the Software-Defined Networking SDN controller using a Northbound Application Programming Interface Northbound API. When a customer requests a service, the developed SDNBroker schedules cloud serving resources using the linear programming algorithm and optimizes network routing using Dijkstras algorithm. Three cloud-serving systems and three applications were utilized to validate SDNBroker. The proposed SDNBroker system is 5i¾?%i¾?~i¾?15i¾?% more efficient than the specified cloud serving system which is a NonSDNBroker system with single routing path. Furthermore, the network link utilization of the proposed route procedure is increased from that of the specified cloud serving system NonSDNBroker system with single routing path by approximately 5.8i¾?%.