• Annual Conference of KIPS
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• 2002.11b
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• pp.1193-1196
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• 2002

본 연구는 접속 요구가 많은 웹 서버의 부하를 두개의 웹 서버로 분산시켜 보다 효율적인 웹 서비스를 제공함과 동시에, 두 웹 서버의 용도에 맞게 재전송 타임아웃(RTO:Retransmission Timeout)을 독립적으로 설정하여 네트워크의 효율성을 제고하기 위해 시도되었다. 이를 위해 Linux 기반의 PC에 라우터를 구축하고, 접속의 요구에 따라 두개 중 하나의 Web 서버에 접속되게끔 라우터를 설정하였다. 웹 서버는 내부 접속용과 외부 접속용으로 구분하였으며, 각각의 서버마다 재전송 타임아웃(RTO:Retransmission Timeout)값을 다르게 설정하여 네트워크에서의 지연(delay)을 최적화시켜 클라이언트의 요청에 대한 응답시간을 최소화시켰다. 전송거리가 짧은 내부 접속용 웹 서버에는 패킷 손실이 거의 없으므로 작은 RTO 값을 설정하고, 외부 접속용 웹 서버에는 큰 RTO 값을 설정하였는데 RTT(Round Trip Time:응답시간)와 Tput(Throughput:처리율)의 출력 결과를 통해 Web 서버의 성능 향상을 확인 할 수 있다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1831-1832
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• 2007

WWW(World Wide Web)의 개발 이래 내 컴퓨터 안에만 존재하는 워드와 한글 등의 문서들은 네트워크를 타고 지구 어딘가에 있는 누군가의 모니터에 디스플레이되고 있다. 그러나 컴퓨터 기술은 이와 같은 단순한 HTML파일을 보여주기보다 방명록이나 동영상처럼 동적으로, 실시간으로 정보를 보여주는 수준으로 진화해야 했다. 이러한 기술을 처음으로 가능하게 한 것이 CGI 기술이다. 초기의 CGI 기술은 성능상의 문제로 개발과 발전을 거듭해 현재의 FastCGI나 mod_perl과 같은 기술이 제안되었다. 그러나 FastCGI나 mod_perl도 아직은 동적 정보를 제공하는 완벽한 기술은 아니며 각각 장단점을 지니고 있다. 본 논문에서는 각 기술의 장단점을 살펴보고 이들의 장점을 통합한 개선된 CGI기술을 제안한다.

• Journal of Information Technology Services
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• v.17 no.3
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• pp.63-75
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• 2018

In this paper, we propose a testing method of the quality of device application effectively reflecting the necessity of increasing mobile device application quality test, and designed and developed it as a web system. We have studied traditional software testing methods for designing and developing a system. We have developed a next-generation alternative technology that can analyze and compensate for the weaknesses of the web and weaknesses of the Android in order to realize the access system and the responsive web system. As an example applied to the system, we analyzed the requirements of the system implementation and expressed the functions of the system through the use case diagram. The test scenarios were conducted by connecting 5,000 devices to each system using the existing HTTP polling method and the proposed web socket method. After setting the comparative group, the result of the proposed web management system was observed and compared through repeated tests. The research shows that the proposed web socket system has better performance than HTTP polling. The more the number of simultaneous processing of the devices, the lower the server stability but the better the time efficiency. In conclusion, the more the number of devices to be tested is, the more the number of devices can be effectively tested using the proposed web management system.

• 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.

• International Journal of Contents
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• v.11 no.1
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• pp.41-51
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• 2015

Management systems for electronic library have been developed on the basis of Client/Server or ASP framework in domestic market for a long time. Therefore, both service provider and user suffer from their high cost and effort in management, maintenance, and repairing of software as well as hardware. Recently in addition, mobile devices like smartphone and tablet PC are frequently used as terminal devices to access computers through the Internet or other networks, sophisticatedly customized or personalized interface for n-screen service became more important issue these days. In this paper, we propose a new scheme of integrated management system for electronic library based on SaaS and Web Standard. We design and implement the proposed scheme applying Electronic Cabinet Guidelines for Web Standard and Universal Code System. Hosted application management style and software on demand style service models based on SaaS are basically applied to develop the management system. Moreover, a newly improved concept of duplication check algorithm in a hierarchical evaluation process is presented and a personalized interface based on web standard is applied to implement the system. Algorithms of duplication check for journal, volume/number, and paper are hierarchically presented with their logic flows. Total framework of our development obeys the standard feature of Electronic Cabinet Guidelines offered by Korea government so that we can accomplish standard of application software, quality improvement of total software, and reusability extension. Scope of our development includes core services of library automation system such as acquisition, list-up, loan-and-return, and their related services. We focus on interoperation compatibility between elementary sub-systems throughout complex network and structural features. Reanalyzing and standardizing each part of the system under the concept on the cloud of service, we construct an integrated development environment for generating, test, operation, and maintenance. Finally, performance analyses are performed about resource usability of server, memory amount used, and response time of server etc. As a result of measurements fulfilled over 5 times at different test points and using different data, the average response time is about 62.9 seconds for 100 clients, which takes about 0.629 seconds per client on the average. We can expect this result makes it possible to operate the system in real-time level proof. Resource usability and memory occupation are also good and moderate comparing to the conventional systems. As total verification tests, we present a simple proof to obey Electronic Cabinet Guidelines and a record of TTA authentication test for topics about SaaS maturity, performance, and application program features.

• Annual Conference of KIPS
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• 2006.11a
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• pp.227-230
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• 2006

A content-based image retrieval system using MPEG-7 is designed and implemented in this thesis. The implemented system uses existing MPEG-7 Visual Descriptors. In addition, a new descriptor for efficient retrieval of bio images is proposed and utilized in the developed content-based image retrieval system. Comparing proposed CBSD(Compact Binary Shape Descriptor) with Edge Histogram Descriptor(EHD) and Region Shape Descriptor(RSD), it shows good retrieval performance in NMRR. The proposed descriptor is robust to large modification of brightness and contrast and especially improved retrieval performance to search images with similar shapes. Also proposed system adopts distributed architecture to solve increased server overload and network delay. Updating module of client efficiently reduces downloading time for metadata. The developed system can efficiently retrieve images without causing server's overload.

• The KIPS Transactions:PartD
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• v.14D no.4 s.114
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• pp.421-426
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• 2007

In this paper, we are to overcome the latency problem of current Web 2.0 Web Services system. To overcome the standard mobile web services implementation, a SOAP message processing system (SMSP) was proposed in which the SOAP request and response messages are directly processed without using Servlet engine. Our system can completely support standard Web Services protocol, reducing communication overhead, message processing time, and server overload.

• The KIPS Transactions:PartD
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• v.9D no.3
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• pp.457-466
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• 2002

In this paper, we designed and implemented a web-based dictionary of computing which keeps the data up-to-date. This dictionary shows the English information based on the FOLDOC (Free On-Line Dictionary Of Computing) dictionary file at the beginning of searching, and then one or more users can translate the information into Korean. This function is the new one only this dictionary has. Also, we can easily find any words we want to took up, even if we don't know the spelling completely, because the dictionary has various searching interfaces (searching for the words starting with inputted characters, searching for the words including inputted characters in the description, etc.) using a SQL Server DBMS and SQL. The performance test for CPU load factor shows that the server can support at least 1780 users at the same time.

• The KIPS Transactions:PartD
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• v.12D no.6 s.102
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• pp.915-920
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• 2005

In this paper we expanded a existing web based B2B system to support users in low speed network. To guarantee shared dat a consistency between clients and a server, we proposed a method of data change detection by using a time stamp tree and the performance analysis of the proposed method was proved by a simulation. Under the worst condition that leaf nodes of a times tamp tree were changed uniform distribution, the simulation result showed that the proposed method was more efficient than a sequential detection until the percentage of changed nodes were below $15\%$. According to our observation, the monthly average of data change was below $7\%$ on a web-based construction MRO B2B system or a company A from April 2004 to August 2004. Therefore the Proposed method improved performance of data change detection in practice. The proposed method also reduced storage consumption in a server because it didn't require a server to store replicated data for every client.

• Korean Journal of Remote Sensing
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• v.28 no.4
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• pp.467-475
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• 2012

Cloud computing services are known that they have many advantages from the point of view in economic saving, scalability, security, sharing and accessibility. So their applications are extending from simple office systems to the expert system for scientific computing. However, research or computing technology development in the geo-spatial fields including remote sensing applications are the beginning stage. In this work, the previously implemented smartphone app for image processing was first migrated to mobile cloud computing linked to Amazon web services. As well, parallel programming was applied for improving operation performance. Industrial needs and technology development cases in terms of mobile cloud computing services are being increased. Thus, a performance testing on a satellite image processing module was carried out as the main purpose of this study. Types of implementation or services for mobile cloud varies. As the result of this testing study in a given condition, the performance of cloud computing server was higher than that of the single server without cloud service. This work is a preliminary case study for the further linkage approach for mobile cloud and satellite image processing.