Jin-Gwang Koh

Multipath Routing Method for Supporting QoS and Improving Energy Efficiency in WMSNs

QoS support is essential for differentiated data processing according to types and characteristics of traffics occurred from various applications such as environment monitoring, disaster control and data collection as well as efficient use of energy in order to transmit the multimedia data in Wireless Multimedia Sensor Network (WMSNs). This paper proposes a multipath routing method which may extend the life time of the whole network by supporting QoS of WMSNs and improving the energy efficiency. The proposed multipath routing method sets the path considering the distance to sink node, remaining energy of node and link quality. In addition, setting the path according to characteristics of packet in order to support the differentiation of service for guaranteeing QoS is based on the path cost. The proposed method improve the energy efficiency while securing the reliability by enhancing the packet transmission rate, reducing the packet loss rate and delay time preventing the concentration of energy consumption through the multipath and subsequent reorganization of the path.

An Enhanced Adaptive Power Control Mechanism for Small Ethernet Switch

Ethernet is the most widely deployed access network protocol around the world. IEEE 802.3az WG released the EEE standard based on LPI mode to improve the energy efficiency of Ethernet. This paper proposes improved adaptive power control mechanism that can enhance energy-efficiency based on EEE from small Ethernet switch. The feature of this mechanism is that it predicts the traffic characteristic of next cycle by measuring the amount of traffic flowing in during certain period and adjusts the optimal threshold value to relevant traffic load. Performance evaluation results indicate that the proposed mechanism improves overall performance compared to traditional mechanism, since it significantly reduces energy consumption rate, even though average packet delay increases a little bit.

Implementation of ebXML Message Transaction supported on a Security and Reliability for Effective e-Business

In this paper, we propose the development strategy of message transaction system in electronic business to business system with consideration of security. B2B must be designed to transfer electronic data between business and business in completely secured and reliable form. For the purpose of secured and reliable transaction of electronic data, we propose the complete framework . Also, we provide message system for communication and transaction for E-business, and provide message test set through the development strategy for interoperability of message. The message test set is a data class modeling of ebXML MSH(message service handler) which supports message test set to ebXML message transaction of e-business. Finally, we implemented the message processing system through SMTP Mail transaction into ebMSH for the ebXML Message Test-Set for message service transaction after database relationship.

An Efficient Image Transmission System Adopting OFDM Based Sequence Reordering Method in Non-flat Fading Channel

In this paper, we propose an OFDM-based image transmission system using the information of channel magnitude response. Transmitter of the proposed system reorders OFDM input sequence according to the channel magnitude response for high quality image transmission. In reordering input sequence of OFDM, the lower spatial frequency components of an image are assigned to the OFDM subcarriers transmitted on the frequency band with the higher channel magnitude response, and vice versa. The channel is assumed to have a spectrum of two ray fading. Through the simulation, it is found that the received image quality of the proposed system outperforms that of conventional system.

Traffic Control Scheme of ABR Service Using NLMS in ATM Network

ATM ABR service controls network traffic using feedback information on the network congestion situation in order to guarantee the demanded service qualities and the available cell rates. In this paper we apply the control method using queue length prediction to the formation of feedback information for more efficient ABR traffic control. If backward node receive the longer delayed feedback information on the impending congestion, the switch can be already congested from the uncontrolled arriving traffic and the fluctuation of queue length can be inefficiently high in the continuing time intervals.

Design of dynamic slot assignment protocol for wireless communication

In this paper, we propose and analyze a wireless MAC protocol named APRMA, which is capable of supporting the ABR type data service and maximizing channel utilization. In original PRMA protocol, data terminals cannot reserve slot. So several types of schemes for supporting data traffiic, but most of them are too complicate to implement. So we propose an efficient and simple MAC protocol for wireless communication. In this study, the terminal which wants to request for ABR type service, acquires a minimum bandwidth from system for the first time. If the system have extra available bandwidth, ABR terminals would acquire additional bandwidth slot by slot. As a result, APRMA protocol can support the data service with loss sensitivity and maintain their channel utilization highly. Also high priority services like voice can be satisfied with their QoS by APRMA.

Performance improvement of DS/CDMA system under impulsive noise environments

In this paper, we have evaluated the BER performance of an asynchronous DS/CDMA BPSK system using a conventional receiver under impulsive noise environments, and have proposed a selective hard limiting(SHL) receiver in order to compensate for the performance degraded by the impulsive noise. As a result, we show that, under impulsive noise environment, the performance of the proposed receiver is much better than that of the conventional CDMA receiver or the hard limiting CDMA receiver. Hence, we can conclude that the SHL receiver proposed in this paper is an effective CDMA receiver in sense of capability to overcome the impulsive noise environments.