• Journal of the Korea Society of Computer and Information
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• 제10권4호
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• pp.337-344
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• 2005

UDDI server is the web services registry enabling users to register and search for web services. However, the existing UDDI servers do not provide any information about web services qualify. We designed and developed a UDDI broker system which actively monitors and analyses the qualify of web services. The analysis results are presented to users in statistical figures and graphs. With this information a user can select a web service that meets his/her needs. Availability, performance, and stability were the metrics used for the service qualify measurement and analysis.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제42권12호
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• pp.95-102
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• 2005

This paper is purpose for improvement performance wireless lan of IEEE802.11a/b/g. Access point utilized a single server, multi-queuing system, FIFS system model to adapted priority multi-bufferto be alteration packet type. The main purpose of the paper improve the transmission rate and the performance of access point to settle transmission delay for load in MAC, has priority multi-buffer. We use experimentation to obtain our model of the access point and buffer-related parameters. Using our test design, we are able to extract the parameters of an analytic equation giving the average service time of a packet as a function of packer IP payload.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제36권3B호
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• pp.268-274
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• 2011

Recently, we could witness research works on the development of mobile harbor. In line with the implementation of the physical entity for the mobile harbor system, there exists a need for the development of the service management system for the mobile harbor. In this work we propose a framework for the mobile harbor service management system. To that purpose, we first define the principle for the operation of the mobile harbor service management system. Also we develop the mobile harbor service management system by simulation. Finally, we illustrate the implication of the research by experiments.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2005년도 하계학술대회
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• pp.329-332
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• 2005

In this paper, we describe implementation of personal media gateway (PMG) for applications over BcN networks. PMG is a TV based set-top terminal, which enables transmission of Full D1 high quality video and audio at the speed of maximum 2Mbps. It supports SIP protocol and QoS for the BcN networks. The hardware of the PMG consists of host module, audio/video codec processing module, DTMF module, and remote control I/O module. H.263 and MPEG4 software are implemented in DSP as codec for hi-directional communication and streaming, respectively. G.711 and Ogg-Vorbis are implemented as audio codec. We examined the quality of video using the Video Quality Test Equpment, which was developed by KT Convergence Lab. The experimental results show the video quality of MOS 4.1 and audio quality of MOS 4.3. We expect that PMG will be prospective business models, and create new customer value.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제11권5호
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• pp.906-914
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• 2007

In the upstream link of EPON, numerous ONUs In the reverse link of the EPON network, numerous ONUs receive the privileges to use the optical medium from the scheduler of the LOT, but not through the competition with others. Therefore, it is very important to select a proper DBA algorithm to allocatethe frequency band to each ONU in an effectively and fair manner. In our preceding study, we proposed the RC-DBA algorithm that complements many problems in existing DBA algorithms. In this paper, we designed the MAC scheduler for the OLT, which the proposed algorithmwas applied to and implement it in the FPGA. In addition, in order to verify the operation of the scheduler, we developed the embedded Linux based testbed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.733-736
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• 2009

Power Line Communication(PLC) is need not additional communication line. So establishment expense is inexpensive and application is simple. Therefore, lower part network of various application field is possible. However, there are high subordinate interference and noise problem on limited transmission data and communication interference element. Wireless Sensor Network(WSN) is need not infrastructure, Self-regulating network architecture of sensor nodes is possible. So at short time, network construction is available. But, power consumption is increased by active sensing for QoS elevation and unnecessary information transmission, low electric power design and necessity of improve protocol are refered to life shortening problem and is studied. In this paper, supplement problem of power line communication and wireless sensor network mutually and because advantage becomes linkage integration control system using synergy effect of two technologies as more restriction be and tries to approach structurally control network that is improved for smooth network environment construction. Honeywell's hybrid sensor network does comparative analysis(benchmarking). Confirm performance elevation proposing teaming of power line communication and wireless sensor network. Through simulation, service delay decreases and confirms that performance elevation.

• Journal of KIISE:Computing Practices and Letters
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• 제6권4호
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• pp.430-440
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• 2000

To support Integrated Services in the Internet, the Internet Engineering Task Force(IETF) has developed new mechanisms. These new mechanisms include Resource Reservation Protocol(RSVP) and Integrated Services model. RSVP and Integrated Services are independent of the underlying link layer technologies and it is necessary to define the mapping of RSVP and Integrated Services specifications onto specific link layer technologies. IETF proposed a Subnet Bandwidth Manager(SBM) providing a method for mapping RSVP onto IEEE802 style networks. However, the SBM has several constraints and problems. For solving these constraints and problems, we design and implement a new Ethernet Bandwidth Manager(EBM). This paper discusses (1) new bandwidth management mechanism independent of RSVP, (2) simulation of Ethernet bandwidth to analyze the characteristics of Ethernet and accomplish Ethernet bandwidth management, (3) design and implemetation of EBM that allows Controlled-Load Service, and (4) results of our experiments on EBM.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제47권1호
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• pp.1-9
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• 2010

In this paper we propose a scheduling algorithm for supporting Quality of Service(QoS) in IEEE 802.11e HCCA referred to as ASR-DRR and ASD-DRR, which aims at providing improved performance for the support of multimedia traffic. Although We identify the problem of the current IEEE 802.11e HCCA (Hybrid Coordination Function Controlled Channel Access) scheduler and its numerous variations, that the queue information cannot be notified to the Hybrid Coordinator (HC) timely, therefore the uplink delay lengthens unnecessarily. We suggests a simple solution and a couple of implementation practices, namely the Adaptive Scheduler with RTS/CTS (ASR) and Adaptive Scheduler with Data/Ack (ASD). They are both further elaborated to emulate the Deficit Round Robin (DRR) scheduler. They are also compared with existing exemplary schedulers through simulation, and shown to perform well.

• Journal of Korea Multimedia Society
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• 제9권8호
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• pp.1020-1029
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• 2006

Realization of high-capacity quality-of-service router needs fair packet schedulers with a lower complexity. Timestamp based fair packet schedulers have the ideal complexity of O(log V), where V is the maximum number of admitted flows, but it has been recently reduced to O(1) using bin concept. However, the latency property was deteriorated and the bandwidth utilization was also declined. In addition, traffic flows requiring strong delay bound may not be admitted. To overcome these problems, this paper proposes a Mini-Bin based Start-Time (MBST) scheduler with variable complexity and evaluates its performance. The MBST scheduler uses the timestamp calculation scheme of start-time based schedulers to enhance the bandwidth utilization and also introduces mini-bin concept to improve the latency, The performance evaluation shows that the proposed scheduler can reduce the complexity of the legacy start-tine based schedulers by $1.8{\sim}5$ times without deteriorating the bandwidth utilization property.

• Journal of KIISE:Information Networking
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• 제30권2호
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• pp.260-269
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• 2003

The traditional distributed object middleware platform is not suitable for the transmission of stream data, because RPC(Remote Procedure Call)-based message transmission have a great overhead. Therefore, the OMG(Object Management Group) proposes the AV(Audio and Video) stream reference model for streaming on the distributed object middleware platform. But, this reference model has not a detail of implementation. Particularly it also has not congestion control scheme for improvement of network efficiency on the real network environment. It is a very important and difficult technical issue to provide the stream transmission platform with advanced congestion control scheme. In this paper, we propose an architecture of a distributed stream transport platform and deal with the design and implementation concept of our proposed platform. Also, we present a mechanism to improve streaming utilization by SRTP(Smart RTP). SRTP is our proposed TCP-Friendly scheme.