Young-Bok Choi

RFID-Based RTLS for Improvement of Operation System in Container Terminals

Shipping companies consider most of the ship turnaround time as a critical factor when selecting a calling port for reducing costs. Container terminal operator tries to improve the port quality of service requested by a shipping line to maximize the productivity of container terminals. Therefore, this thesis proposes RFID (radio frequency identification)-based RTLS (real time location system) for enhancing the performance of terminal operation system. The suggest container terminals yard allocation for ubiquitous computing is based on current yard allocation algorism. What is difference from the existed algorism is that it shall not apply container-loading sequence to each of independent containers, but shall apply to each of group in use the RFID based RTLS. In addition, preplanning based on ubiquitous computing environment will support working of gantry cranes and yard tractors, and shorten ship turnaround time, more efficiently. It can accomplish the whole lead-time of port logistics

An effective BECN /CRN typed deflection routing for QoS guaranteed optical burst switching

In recent years, WDM networks have received much attention as the Internet backbone networks because of the explosive growth of the Internet IP-based traffic. The optical burst switching (OBS) has been proposed as an effective optical switching technology in the WDM networks (C. Qiao and M. Yoo, 1999). OBS has the advantages in 1) the high usage rate of the bandwidth, and 2) no necessity of optical buffer. However OBS has the burst-contention problem in the networks. The deflection routing is proposed as one of means to solve this problem. In this paper, we propose a new routing method of using deflection routing. In addition, we propose a QoS/CoS control method using a new routing algorithm. Finally, we show the variety of the proposed methods by computer simulations.

Feedback-based Load Balancing Routing for Optical Burst Switching Networks

An optical burst switching (OBS) network provides preferable broadband infrastructure, and is a promising strong candidate for the future optical Internet. However, there is a major deficiency of the OBS, which occurs when multiple bursts contend for the same link and leads to bursts loss. As an effective method to resolve the above important issue of OBS networks, deflection routing has been proposed. A simple deflection routing without proper routing control cannot sufficiently distribute the traffic of bursts and guarantee ideal performance of OBS particularly for heavy traffic condition. In this paper, we propose a new approach for deflection routing in order to reduce the burst loss and minimize end-to-end delay. The simulation results show that the proposed scheme improves the network utilization and minimize both the burst loss probability and end-to-end delay

Effective Flow-rate Control for the Deflection Routing based Optical Burst Switching Networks

Optical burst switching (OBS) has been proposed to realize the next generation Internet on the wavelength division multiplexing (WDM) network technology. In OBS, the burst contention is the major problem. The deflection routing has been designed for resolving this problem. However the deflection routing cannot prevent the burst contention as the network load becomes high. In this paper, we show that a flow-rate control is essential for OBS. We propose leaky bucket deflection method (LB Deflection method). In LB deflection method, edge nodes which generate data bursts carry out a flow-rate control based on leaky bucket method In order to verify the effectiveness of a flow-rate control in OBS, we show that LB Deflection method improves the network utilization and reduces the burst loss probability through computer simulation

A feedback-based contention resolution mechanism for slotted optical burst switching

Optical burst switching (OBS) has been proposed for an effective optical switching technology of WDM networks in broadband Internets. OBS has the advantages, i.e. 1) the high usage rate of the bandwidth and 2) no necessity of optical buffer. However, OBS has the burst-contention problem in control packet phase, and faces to the reduction of the network performance. Recently, slotted OBS has been proposed. The basic performance of slotted OBS is superior to the original OBS. However, slotted OBS itself cannot overcome the burst-contention problem, either. In this paper, we will adapt BECN/CRN typed deflection routing to slotted OBS to obtain the large improvement of the optical network performance. We also present two new schemes for slotted OBS to improve the burst contention problem, i.e. a) enforced waiting control and b) scheduling.

A large capacity photonic ATM switch for wavelength division multiplexing networks

Optical switching networks to transport vast amounts of information are important for B-ISDN services. Wavelength division multiplexing (WDM) is emerging as the dominant technology for future optical networks. A large capacity photonic ATM switch architecture using WDM technology is proposed in this paper. The proposed switch is suitable for WDM optical ATM networks, that is, the input and an output of the switch are wavelength division multiplexed. The switch can provide very large ATM cell switching capacity, for instance, 10 Tbit/s, with reasonable complexity. The basic switch module of the proposed switch has a simple architecture, and reduces the amount of a buffer hardware by introducing the WDM concept.

An Effective Traffic Control Method for Real-Time and Reliable Bursts in OBS Networks

Optical Burst Switching (OBS) [1][2][3][4] has been proposed for the next generation Internet based on the Wavelength Division Multiplexing (WDM) [5] network technologies. In the OBS, the serious problem is the burst loss due to the burst contention. There have been a number of traffic control methods [6][7] for solving the burst contention problem. The Internet has two traffic classes, i.e. real-time bursts and reliable bursts. However, most of the conventional traffic controls aren’t suitable for the real-time bursts.

Ad-hoc Network Routing Protocol in the Yard of Automated Container Terminal

In this paper, the RFID-based ad-hoc network is presented for the efficient yard management of the container terminal. The loading and unloading work is performed through the ad-hoc communication between YT and GC, YT and TC within the yard without the control of the central server. That makes the efficient operation of the yard with real task correspondence. Using the location information of the RFID tag, we have proposed the routing protocol which is suitable for the yard environment of the container terminal. The performance evaluation has been carried out through the network simulator and gained an effective results.