• Journal of Advanced Marine Engineering and Technology
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• v.29 no.6
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• pp.678-684
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• 2005

In this Paper telemetering system for home automation is Proposed and implemented. Proposed and developed systems are composed with a home server and a few clients which send metering data of gas electric power water and home security to home server using power line communication. Management computer located in office of apartment complex collects all kinds of measured home data from each home server with multi drop communication by UDP Protocol A simple ASK method is used for power line communication Collected data from each home can be used for issuing the bill of each house and web service. The experiments were carried out under laboratory environment using various kinds of electric home appliances to ascertain the performance.

• Asia pacific journal of information systems
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• v.6 no.1
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• pp.21-38
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• 1996

This paper investigates the performance improvement opportunities through a resiliency mechanism in the distributed primary/backup database system. Recognizing that a distributed transaction executes at several servers during its lifetime, we propose a resiliency mechanism which allows continuous transaction processing in distributed database server systems in the presence of a server failure. In order to perform continuous transaction processing despite failures, every state change of a transaction processing can be saved in the backup server. Obviously, this pessimistic synchronization may give more burdens than benefits to the system. Thus, the tracking needs not be done synchronously with the transaction progress. Instead, the state of all transaction processing in a system is saved periodically. This activity is referred to as a savepoint. Then, the question is how often the savepoint has to be done. We derive the optimal savepoint to identify the optimization parameters for the resilient transaction processing system.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.171-179
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• 2014

Among the P2P based multimedia streaming architecture, multiple chain architecture has advantage in adapting to dynamically changing network topology simply and rapidly, so this architecture is used for UCC broadcasting system. In UCC broadcasting system, general peer involved in DSLAM becomes UCC server rather than broadcasting system that transfers data from ISP servers. Therefore UCC data generated from UCC server peers is transmitted to peers through DSLAM, and this transmission uses uplink bandwidth of DSLAM. In this paper, I propose an efficient management method of DSLAM uplink bandwidths through negotiating tracker and UCC server peer or head peers of DSLAM. I propose the method that tracker restricts a bitrate of uplink stream of UCC servers when used uplink bandwidth of DSLAM exceeds a certain point of maximum uplink bandwidths. I will show the improved performance of proposed scheme rather than general method with respect to the uplink bandwidth of DSLAM by numerical analysis and simulation.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1706-1711
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• 2008

This paper proposes a new Web based-control concept & design method and implementation of LonWorks network system for a large scale renewable energy energy control and monitoring system in building. The Experimental LonWorks network system using LonWorks/Ethernet(Web) server is designed and fabricated. This article addresses issues in architecture of LonWorks/Ethernet sever, embedded processors architecture for converting LonTalks protocol to Modbus protocol and software, and Internet technologies. It is also verified that the multi-induction motor control and monitoring system using LonWorks/Ethernet server have available, interoperable, reliable performance characteristics from the experimental results, Especially, The seamless integration of TCP/IP networks with control networks allows access to any control point from anywhere. Thus, the results provide a available technical data for remote distributed control system of industrial and buildings field.

• Knowledge Management Research
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• v.19 no.1
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• pp.119-132
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• 2018

Many advanced products and services are emerging in the market thanks to data-based technologies such as Internet (IoT), Big Data, and AI. The construction of a system for data processing under the IoT network environment is not simple in configuration, and has a lot of restrictions due to a high cost for constructing a high performance server environment. Therefore, in this paper, we will design a development environment for large data analysis computing platform using open source with low cost and practicality. Therefore, this study intends to implement a big data processing system using Raspberry Pi, an ultra-small PC environment, and open source API. This big data processing system includes building a portable server system, building a web server for web mining, developing Python IDE classes for crawling, and developing R Libraries for NLP and visualization. Through this research, we will develop a web environment that can control real-time data collection and analysis of web media in a mobile environment and present it as a curriculum for non-IT specialists.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.773-778
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• 2014

Recently both high performance and low noise for a cooling fan used in a server computer have been required. In this study, we measured the noise characteristics for a small cooling fan used in a computer or in a server, and compared the computational data to measured ones. SC/Tetra V10 and FlowNoise V4.3 was used for the unsteady flow field and the aeroacoustic analysis, respectively. The aeroacoustic analysis results have the good agreement with measured data within 3% errors in overall SPL. In the noise spectrum, we could find the peak tonal noise at lower frequency than 1st BPF, and confirm that the reason is caused by the asymmetry of bell mouth shape.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.8
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• pp.27-36
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• 1997

In this paper, we propose a locating strategy using a cache based on the distributed call processing stucture. In our stategy, each originating call server, withc is responsible for call setup, has a cache to memorize the service ratio of call server which serves the called terminal.We present performance comparison of the proposed strategy with the existing strategy via simulation. We can reduce the cost for call setup because the originating call server can simpley establish a call without tracing the location of the called terminal. The proposed strategy also reduceds network loads caused by signaling at call setup time and lessens the frequency of queries for the database systems which can be a bottleneck when it serves many subscriber.

• Annual Conference of KIPS
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• 2002.04a
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• pp.381-384
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• 2002

This paper describes the motivation, design and performance of bi-active Load balancer in Linux Virtual Server. The goal of bi-active Load balancer is to provide a framework to build highly scalable, fault-tolerant services using a large cluster of commodity servers. The TCP/IP stack of Linux Kernel is extended to support three IP load balancing techniques, which can make parallel services of different kinds of server clusters to appear as a service on a single IP address. Scalability is achieved by transparently adding or removing a node in the cluster. and high availability is provided by detecting node or daemon failures and reconfiguring the system appropriately. Extensive simulation reveals that the proposed approach improves the reply rate about 20% compared to earlier design.

• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2790-2796
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• 1999

In video-on-demand systems, the I.O bandwidth of video servers is the critical resource which contributes to increase in latency. Several approaches: bridging, piggybacking are used to reduce the I/O demand on the video server through sharing. Batching delays the requests for the different videos for a batching window so that more requests for the same video arriving during the current batching window may be served using the same stream. In this paper, we propose an adaptive reservation-based batching policy which dynamically reserves video server capacity for popoular videos according to video server loads. The performance of the proposed policy is evaluated through a simulation, and is compared with simple batching and static reservation-based batching policies. As the result, we know that the adaptive reservation-based batching policy more improves service ratio and average waiting time than simple batching and simple reservation-based batching policy more improves service ratio and average waiting time than simple batching and simple reservation-based batching polices.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.7-9
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• 2001

웹 사용자들 중 멀티미디어로 제공되는 동영상 Streaming 정보에 접근하는 사람의 비율이 매우 빠르게 증가하고 있는 요즘 이러한 멀티미디어 Streaming 서비스를 좀 더 많은 사람들에게 양질의 서비스를 하려면 어떤 부분의 개선이 요구되어지며, 또 이 Streaming 서버가 어떠한 형태의 서비스를 하는지, 어느 정도의 시스템을 필요로 하는지에 대하여 알아보기 위하여 Streaming 서비스를 해주는 일반적인 서버를 보통의 하드웨어성능을 가지는 PC에 설치하여 실험하여 보았고 그 결과로 서버를 구성하는데 있어서 Streaming Server들이 가질 수 있는 문제 즉 Load가 발생되는 부분을 알아보고 있다. 실험의 결과로 볼 때 현재 일반적인 PC나, Streaming Server Hosting을 하는 업체에서 사용하고 있는 서버하드웨어는 Streaming service를 하기에는 적합하지 않지만, 문제점을 알고 적절한 하드웨어 Resource의 추가로 좀 더 효과적인 서비스를 할 수 있도록 하고자 한다.