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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 31, Issue 12C - Dec 2006
Volume 31, Issue 12B - Dec 2006
Volume 31, Issue 12A - Dec 2006
Volume 31, Issue 11C - Nov 2006
Volume 31, Issue 11B - Nov 2006
Volume 31, Issue 11A - Nov 2006
Volume 31, Issue 10C - Oct 2006
Volume 31, Issue 10B - Oct 2006
Volume 31, Issue 10A - Oct 2006
Volume 31, Issue 9C - Sep 2006
Volume 31, Issue 9B - Sep 2006
Volume 31, Issue 9A - Sep 2006
Volume 31, Issue 8C - Aug 2006
Volume 31, Issue 8B - Aug 2006
Volume 31, Issue 8A - Aug 2006
Volume 31, Issue 7C - Jul 2006
Volume 31, Issue 7B - Jul 2006
Volume 31, Issue 7A - Jul 2006
Volume 31, Issue 6C - Jun 2006
Volume 31, Issue 6B - Jun 2006
Volume 31, Issue 6A - Jun 2006
Volume 31, Issue 5C - May 2006
Volume 31, Issue 5B - May 2006
Volume 31, Issue 5A - May 2006
Volume 31, Issue 4C - Apr 2006
Volume 31, Issue 4B - Apr 2006
Volume 31, Issue 4A - Apr 2006
Volume 31, Issue 3C - Mar 2006
Volume 31, Issue 3B - Mar 2006
Volume 31, Issue 3A - Mar 2006
Volume 31, Issue 2C - Feb 2006
Volume 31, Issue 2B - Feb 2006
Volume 31, Issue 2A - Feb 2006
Volume 31, Issue 1C - Jan 2006
Volume 31, Issue 1B - Jan 2006
Volume 31, Issue 1A - Jan 2006
Selecting the target year
Design and Performance Evaluation of Hybrid Two-Stage AWG based WDM-PON Architecture
Han Kyeong-Eun ; Lee Seung-Hyun ; Kim Young-Chon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 573~582
In this paper, we propose a hybrid two-stage AWG-based WDM-PON architecture in order to overcome the limitations of the existing PONs and single AWG-based WDM-PONs as well as to accomodate the new services and the expandability of network. The proposed architecture employs two-stage AWG for downstream transmission and single AWG and combiners for upstream one at RN. It also employs the separated fiber with multi-wavelength for both direction. It leads to high scalability, low cost, and high capacity for transmission. In downstream transmission, the transparency can be guaranteed since the traffic is transmitted to ONU through each channel. However, several ONUs share the channel for upstream one by using WDM/TDMA scheme because the asymmetrical feature of networks is considered. The performance of the proposed one is evaluated and compared with other architectures in terms of cost, network capacity and up/downstream bandwidth.
WPIF: The Integration Framework for the Convergence of Heterogeneous WPANs
Kong In-Yeup ; Je Dong-Guk ; Sihn Gyung-Chul ; Kim Dae-Sik ; Hwang Won-Joo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 583~594
WPANs (Wireless personal area networks) have developed as various forms according to requirements such as data rate, coverage, subscriber volume, and supported mobile velocity. And mobile device with multiple network interfaces is very common. To make these multi-mode devices communicate with any WPAN device at anytime, anywhere, the framework for heterogeneous wireless networks is essential. Therefore, we propose the integration framework to converge heterogeneous WPANs. In this paper, we explain the requirements and detailed design of our framework, and then present the emulation test results.
A Study on the Recognizing Range Expansion Techniques of the Ultrasonic Location Awareness System for the Ubiquitous Computing
Park Jong-Jin ; Lee Dong-Hwal ; Kim Su-Yong ; Mun Young-Song ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 595~601
This study presents an ultrasonic location awareness system for the ubiquitous computing with absolute position. The flight time of ultrasonic waves is determined by a period detecting technique which is able to extend the sensing range compared with traditional methods. For location awareness, ultrasonic waves are sent successively from each ultrasonic transmitter and synchronized by radio frequency (RF) signal, where the transmitting part is fixed and the receiving part is movable. To expand the recognizing range, cell matching technique and coded ultrasonic technique are introduced. The experimentation for various distances is accomplished to verify the used period detecting technique of U-SAT system. The positioning accuracy by using cell matching is also verified by finding the locations of settled points and the usability of coded ultrasonic technique is verified. As a result, the possibility of ultrasonic location awareness system for the ubiquitous computing can be discussed as a pseudo-satellite system with low cost, a high update rate, and relatively high precision, in the places where GPS is not available.
A Study of the Method for Subscriber-Aware and Fair Aggregation Scheme in Ethernet
Kwon Tae-Hyun ; Park Jong-Su ; Park Dae-Geun ; Lee Yong-Surk ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 602~607
A subscriber-oriented service became necessary for the QoS management due to the development of network. BcN(Broadband convergence Network) which incorporates communication, broadcasting and internet not only improves the quality of the communication and broadcasting service but also. aims at broadband service. Therefore, QoS management for each subscriber becomes more important. Not yet, however, the discussion for the subscriber oriented QoS management is not activated. Although, there are several techniques for subscriber distinction using flow information, IP information or MAC information, but they are only processed in layer 3 network. Actually, it is impossible to manage QoS of all subscriber's in layer 3 network. In this paper, we propose a method for QoS management scheme that does not need additional processes or large hardware in layer 2 network and analyze efficiency and overheads. We propose the first subscriber-oriented service method in layer 2 network that is applicable to either existing network or BcN.
A Proxy based QoS Provisioning Mechanism for Streaming Service in Wireless Networks
Kim Yong-Sul ; Hong Jung-Pyo ; Kim Hwa-Sung ; Yoo Ji-Sang ; Kim Dong-Wook ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 608~618
The increasing popularity of multimedia streaming services introduces new challenges in content distribution. Especially, it is important to provide the QoS guarantees as they are increasingly expected to support the multimedia applications. The service providers can improve the performance of multimedia streaming by caching the initial segment (prefix) of the popular streams at proxies near the requesting clients. The proxy can initiate transmission to the client while requesting the remainder of the stream from the server. In this paper, in order to apply the prefix caching service based on IETF's RTSP environment to the wireless networks, we propose the effective RTSP handling scheme that can adapt to the radio situation in wireless network and reduce the cutting phenomenon. Also, we propose the traffic based caching algorithm (TSLRU) to improve the performance of caching proxy. TSLRU classifies the traffic into three types, and improve the performance of caching proxy by reflecting the several elements such as traffic types, recency, frequency, object size when performing the replacement decision. In simulation, TSLRU and RTSP handling scheme performs better than the existing schemes in terms of byte hit rate, hit rate, startup latency, and throughput.
Context-aware based TV Application Services in Ubiquitous Computing Environments
Moon Ae-Kyung ; Lee Kang-Woo ; Kim Hyoung-Sun ; Kim Hyun ; Lee Soo-Won ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 619~631
With the advent of ubiquitous computing environments, it has become increasingly important for applications to take full advantage of context information, such as the user's location, to offer greater services to the user without any explicit request. In this paper, we propose context-aware active services on the basis of CAMUS (Context-Aware Middleware for URC Systems). CAMUS is a middleware for providing context-aware applications with development and execution methodology. Accordingly, the applications developed by CAMUS respond in a timely fashion to contexts. To evaluate, we apply proposed active services to TV application domain. Therefore, we implement and experiment the TV contents recommendation service agent, control service agent and TV task based on CAMUS. The context-aware TV task is to recommend programs and control of TV according to user preference, location and voice commands.
Dynamic Frequency Selection Method for Medium Access Control in Cognitive Radio Networks
Jo Kyoung-Jin ; Kim Hyun-Ju ; Roh Kweon-Mun ; Yoo Snag-Jo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 632~641
Recently FCC has considered about the unlicensed device operation in licensed bands. However, this operation can give the harmful interference to the existent licensed system while unlicensed devices operate. Therefore, there should be strict requirements to protect licensed system. So in this paper we propose dynamic frequency selection method in the MAC layer, which is based on the cognitive radio technology. The proposed dynamic frequency selection method creates channel lists after sensing the licensed channels. And it helps the CR base station immediately to moves the current channels that are used by the unlicensed system to other available bands dynamically when a licensed system's signal is detected. This method can reduce interference that is caused by unlicensed devices. In addition, it can maximize channel utilization with enabling coexistence of unlicensed system and licensed system.
A Multi-Rate Aware Distributed Packet Scheduling in Ad-hoc Networks
Roh Kwen-Mun ; Chen Yong-Qian ; Yoo Sang-Jo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 642~651
In ad-hoc network, the most of existing packet scheduling schemes provides throughput-based fairness. To provide throughput-based fairness, it basically supposes that the channel capacity is fixed. But, the supposing that the channel capacity is fixed is not appropriate because IEEE 802.11b and 802.11g which are normally used for organizing ad-hoc network can provide various data rate according to channel conditions. So, we define time-based fairness for each flow to consider multi-rate and suggest the MRADPS reaching the defined time-based fairness. Simulation result shows that MRADPS improves the total network throughput in ad-hoc network with providing time-based fairness to each flow.
Routing Algorithm based on Link Stability for Ad Hoc Wireless Networks
Lim Se-Young ; Kim Hun ; Yoo Myung-Sik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 652~659
The routing algorithm is one of the key research areas in ad hoc networks. The most of existing routing algorithms depends on current availability of wireless link when finding the feasible path. Dependence on current information may mislead to a fragile communication path. Some routing approaches that take statistical average on received signal power enhance the possibility to find the most stable path, but have limitation on considering only the average power level. In this paper, we propose routing algorithm based on link stability for ad hoc network. The proposed algorithm not only takes statistical average, but also traces the degree of variations in received signal power. The simulation result support that the proposed algorithm is more likely to find the most stable path under the severe communication environment.
An Economic Assessment Analysis on Deploying VoWLANs
Cho Nam-Wook ; Ahn Jac-Kyoung ; Kim Ji-Pyo ; Hong Jung-Sik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 660~667
Voice over Wireless LAN (VoWLAN) is defined as a communication service which transmits voice over wireless LAN. Due to its capability of providing high quality service while reducing communication costs, the VoWLAN is expected to be widely introduced to hospitals, hotels, and many more industry sectors. However, despite the increased interest in the new service, there has been limited research on the economic assessment of deploying VoWLAN. This paper provides a systematic and quantitative approach to the return on investment (ROI) analysis of VoWLAN service. We first analyze the domestic and international market trend of VoWLAN. Then, implementing scenarios of VoWLAN and corresponding alternatives are established. For each scenario, cost and benefit analysis is conducted. The proposed framework is implemented by using VBA program. To validate the result of the analysis, a case study is also conducted.
Fast Staggered Data Broadcasting and Receiving Scheme for Simple and Efficient Video on Demand Services
Kim Hong-Ik ; Park Sung-Kwon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 668~678
In designing a video-on-demand (VoD) system, one of the major challenges is how to reduce the viewer's waiting time maintaining a given bandwidth allocation and how to reduce the client's buffer requirements. To solve these problems, many VoD schemes were proposed. However, most VoD schemes require managing many segments of a video, frequency channel hopping, and using many channels at the same time. Therefore, to the complexity is a barrier to implementation. In this paper, we propose a fast staggered broadcasting scheme which has a simple structure and substantially improved VoD efficiency. The numerical results demonstrate that the viewer's waiting time of the fast staggered broadcasting scheme is close to the fast broadcasting scheme and the buffer requirements of this can be adapt for demanding rate by adjusting the short front part of a video sizes.
A Multicast Delivery Technique for VCR-like Interactions in Collaborative P2P Environment
Kim Jong-Gyung ; Kim Jin-Hyuk ; Park Seung-Kyu ;
The Journal of Korean Institute of Communications and Information Sciences, volume 31, issue 7B, 2006, Pages 679~689
Delivering multicast stream is one of the cost-saving approach in the large scale VOD environment. Because implementing VCR-like interactions for user's convenience in the multicast streaming system involves complex problems, we need the proper solutions for them. In this paper, we propose a hybrid scheme which uses the general P2P and the patching scheme with the Collaborative Interaction Streaming Scheme(CISS). CISS provides jumping functionability to the appropriate multicast session after VCR-like interaction in the environment in which multiple peers transmit VCR-like interaction streams to the VCR-like functionability request node to reduce the loads generated by frequent join or departure of peers at the multicast tree during providing VCR-like functionability. Therefore, with the proposed scheme we can distribute network traffic and reduce control overhead and latency. And to evaluate the performance of proposed scheme we compare it in the aspect of the performance of streaming delivery topology, control overhead and streaming quality with P2Cast and DSL. The simulation result shows that proposed P2Patching reduces about 30% of process overhead and enhances about
of streaming quality compared with DSL.