Okhwan Byeon

A Cluster-Based Energy-Efficient Routing Protocol without Location Information for Sensor Networks

With the recent advances in Micro Electro Mechanical System (MEMS) technology, low cost and low power consumption wireless micro sensor nodes have become available. However, energy-efficient routing is one of the most important key technologies in wireless sensor networks as sensor nodes are highly energy-constrained. Therefore, many researchers have proposed routing protocols for sensor networks, especially cluster-based routing protocols, which have many advantages such as reduced control messages, bandwidth re-usability, and improved power control. Some protocols use information on the locations of sensor nodes to construct clusters efficiently. However, it is rare that all sensor nodes know their positions. In this article, we propose another cluster-based routing protocol for sensor networks. This protocol does not use information concerning the locations of sensor nodes, but uses the remaining energy of sensor networks and the desirable number of cluster heads according to the circumstances of the sensor networks. From performance simulation, we found that the proposed protocol shows better performance than the low-energy adaptive clustering hierarchy (LEACH).

A base station centralized simple clustering protocol for sensor networks

Sensor nodes in wireless sensor network are severely energy-constrained. This has been a key factor to limit its performance. So far, many energy-efficient routing protocols have been proposed. Cluster-based routing protocols have been paid much attention because of their advantages. However, the cluster-based routing protocols require information on the locations of the sensor nodes in the network to construct clusters. Due to cost, it is not feasible to know the locations of all sensor nodes in the network. In this paper, we propose a base station centralized simple clustering protocol (BCSP) which requires no location information of the sensor nodes. Instead, BCSP utilizes information on the remaining energy of each sensor node and the number of cluster heads which is changed depending on the circumstance of the sensor network. From performance experiments, BCSP shows better performance than low-energy adaptive clustering hierarchy (LEACH)

Interactive 3D HD video transport for e-science collaboration over UCLP-enabled GLORIAD lightpath

Emerging large-scale applications for e-science and Grid require end-to-end lightpaths that need to be dynamically provisioned with QoS (quality of service) guarantees. In this paper, an e-science collaboration is demonstrated as a part of iGRID2005, where an interactive 3D HD (high definition) video transport is realized over an inter-continental lambda integrated facility on 10 Gbps GLORIAD links. To realize real-time interactive (2-way) collaboration among scientific researchers, the 10 Gbps end-to-end user-controlled lightpath between Korea and USA is dynamically provided with very high network performance. Both uncompressed and stereoscopic HD videos are then exchanged between participating sites. Thus, we verify the potential of proposed e-science collaborations by discussing underlying lambda networking infrastructure, UCLP-enabled dynamic lightpath provisioning, HD video system setup and integration, and demonstration results.

Design and implementation of QoS measurement and network diagnosing framework for IP multicast in advanced collaborative environment

The access grid for collaborative environment exploits IP multicast. Although the IP multicast is quite a promising technology, it faces lots of challenges such as unreliable data transport and unstable network infrastructure. As a first step to achieve reliability and stability in IP multicast, it is essential to monitor and debug multicast networks. In this paper we introduce MMag, a user-oriented multicast monitoring tool for the access grid. The MMag provides both application and network level monitoring facilities to assess delivery statistics and to diagnose multicast problems. The implementation has been tested and will support access grid operators with a simple yet extensive view of multicast performance.

Performance analysis of queue scheduling mechanisms for EF PHB and AF PHB in DiffServ networks

Expedited Forwarding Per-Hop Behavior (EF PHB) and Assured Forwarding Per-Hop Behavior (AF PHB) are the forwarding schemes operating in DiffServ networks. EF PHB is appropriate for flows with low delay, low latency and low jitter, and AF PHB provides guaranteed services with minimum bandwidth and buffer. The two PHB can be implemented by several queue scheduling mechanisms such as weighted round-robin (WRR), priority round-robin (PRR) and priority-weight round-robin (PWRR) which is the queue scheduling mechanism conjoining the WRR and PRR. The EF queue in PWRR is served based on PRR, and WRR mechanism is used in scheduling non-EF queues. In this paper, we evaluate the WRR, PRR and PWRR under the conditions that both EF PHB and AF PHB operate in a DiffServ router. We show PWRR is the best queue scheduling mechanism simultaneously gratifying the delay and jitter criteria of the EF class as well as the target throughput of AF classes.

Effective Iris Recognition System by Optimized Feature Vectors and Classifier

This paper presents an effective system for recognizing the identity of a living person on the basis of iris patterns that is one of the physiological and biological features with high reliability. To represent the iris pattern efficiently, a new method for optimizing the dimension of feature vectors using wavelet transform is proposed. In order to increase the recognition accuracy of competitive learning algorithm, an efficient initialization of the weight vectors and a new method to determine the winner are also proposed. With all of these novel mechanisms, the experimental results showed that the proposed system could be used for personal identification in an efficient and effective manner.

Future Application and Middleware Technology on e-Science

As scientific research increasingly requires the efforts of globally diverse, multidisciplinary teams from different laboratories and organizations, there surfaces a need to facilitate this kind of collaborative work. These large-scale scientific initiatives, where information technology plays an important role, are termed e-Science; e-Science activities employ geographically distributed resources like high performance computing facilities, scientific instruments, databases, and high performance networks. Future Application and Middleware Technology on e-Science presents selected papers from the 2008 Korea e-Science All-Hands-Meeting (AHM 2008). Hosted by the Korea Institute of Science and Technology Information (KISTI), the Korea e-Science AHM was designed to bring together developers and users of e-Science applications and enabling information technologies from international and interdisciplinary research communities. The AHM 2008 conference served as a forum for engineers and scientists to present state-of-the-art research and product/tool developments, and to highlight related activities in all fields of e-Science. The following topics concerning e-Science are covered in this volume: e-Science applications in Physics, Astronomy, and Chemistry e-Science applications in Bio-medicine and Life science e-Science applications in Geo-science with remote sensing e-Science applications in Climates and Earth systems e-Science applications in Engineering (Aerospace, Ship, Automobile, and etc) Grid technologies (Computing, Data, VO, and etc) Collaborative science models and techniques Enabling technologies of Workflows and Web services Resource management and scheduling Problem solving environments Scientific data management Application development environments Robust and transparent middleware Programming paradigms and models Software engineering tools Community development and engagement User outreach, training, and documentation The works presented in this edited volume bring together cross-disciplinary information on e-Science in one cohesive source. This book is suitable for the professional audience composed of industry researchers and practitioners of e-Science. This volume is also suitable for advanced-level students in the field.

Uncompressed high definition visual sharing system towards interactive networked collaboration

Recent growth in available network bandwidth envisions widespread use of broadband applications such as uncompressed Internet HDTV, a cutting-edge application technology for networked collaboration. In this paper, we introduce a cost-effective uncompressed HD visual sharing system and discuss its software architecture in depth. We also illustrate our experiences with the visual sharing system for interactive collaboration. Finally, experimental results will show how well it compensates for packet jitter to gear up media synchronization.

Optimizing System Performance for Uncompressed HDTV over 10-Gigabit Ethernet

Guaranteeing network bandwidth and system performance becomes important technical matters to make seamless delivery of bulky data at high speed. Tuning system and network parameters including jumbo frame, kernel buffer size, and interrupt coalescence determines end-to-end transmission throughput. Additionally, fine-tuning of the parameters alleviates workload on high-end systems. Until now, many studies have concentrated on how to increase transmission throughput but rarely discussed how to mitigate system workload. In this paper, we have investigated various tuning parameters, which positively affect networking and processing performance of uncompressed HDTV system.

Design of Web Simulation and Content Service on EDISON

In order to help students understand various kinds of phenomena on applications, we design the system structure and service of EDucation-research Integration through Simulation On the Net (EDISON) services. In this paper, we focus on students’ activity who utilizes EDISON simulation and contents service with their lecture notes. The designed web simulation service includes reusing of previous simulation workflow and searching workflow and results. Contents also utilize simulation service to verify the knowledge of contents such as lecture notes, reports, and papers. The designed service helps students to understand the knowledge of their learning materials.