• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2137-2142
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• 2003

One of the important performance metrics of the World Wide Web is how fast and precise a request from users will be serviced successfully. Shared Web Caching (SWC) is one of the techniques to improve the performance of the network system. In Shared Web Caching Systems, the key issue is on deciding when and where an item is cached, and also how to transfer the correct and reliable information to the users quickly. Such SWC distributes the items to the proxies which have sufficient capacity such as the processing time and the cache sizes. In this study, the Hot Spot Prediction Algorithm (HSPA) has been suggested to improve the consistent hashing algorithm in the point of the load balancing, hit rate with a shorter response time. This method predicts the popular hot spots using a prediction model. The hot spots have been patched to the proper proxies according to the load-balancing algorithm. Also a simulator is developed to utilize the suggested algorithm using PERL language. The computer simulation result proves the performance of the suggested algorithm. The suggested algorithm is tested using the consistent hashing in the point of the load balancing and the hit rate.

• Journal of Environmental Impact Assessment
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• v.10 no.4
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• pp.319-326
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• 2001

This study is aimed at the development of a comprehensive web-based partial differential equation solver (WPDES) using multidimensional finite element method, which can be operated on the basis of world wide web. Overall issues of engineering and environmental information management and facility control could be implemented using this solver. This paper describes the development technique of the model, which is first part on development of partial differential equation solver. Conventional commercial general solver of computational fluid dynamics problems were investigated. All the relevant environmental models were analyzed to develop integrated environmental management system using WPDES. The governing equations and the parameters of investigated models were analyzed and integrated. Several numerical modules were invented for each partial differential term in partial differential equation of many related modeling problems. Each module was coded in the fashion of object oriented method, and was combined independently for the overall governing equation. WPDES has unique characteristic, which can analyze the problem through the suitable combination of modules without development of additional models for each environment problem with different governing equation, main variables, and parameters.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.1
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• pp.146-158
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• 2002

JPEG is good for full color representation but is poor in quality of image because of the small size and the losing compression ways. GIF is a kind of format style made for image - transmission in Compuserve which is a method of PC communication in U. S. A and now is used in world wide web owing to the efficiency of file compression and transmission. But GIF only is used 256 colors, so the images in web has a poorer quality of colors effect to be compared with those of printed catalogues. Also there can be licence problems when the images is used for commercial uses because the possession is Compuserve. The PNG is a way that the total advantages of JPEG and GIF. PNG image file is a more skillful (bitmap display unit), shows a high quality image like TIFF image about, gives superior compression , a 10% to 30% represents full color, 256 color, gray like JPEG. GIF file which uses LZW compression file is a thing which pays licence, In other hands, PNG is free from licence and more skillful image processing method against image error, and it is possible to conserve the color information. Therefore, this treatise is about how various images which are utilized for commercial printings in web, can be made into PNG files about the compression file. And the representation of image by compared the G]U images with JPEG images as well as compression file and the representation of image the superiority of color representation. In addition, 1 check out how much ranges the PNG files are available for electronic publish printing.

• Journal of Korea Multimedia Society
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• v.9 no.12
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• pp.1552-1559
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• 2006

In a web environment, similar information exists in many different places in diverse formats. Even duplicate information is stored in the various databases using different terminologies. Since most information serviced in the current World Wide Web however had been constructed before the advent of ontology, it is practically almost impossible to construct ontology for all those resources in the web. In this paper, we assume that most information in the web environment exist in the form of RDBMS, and propose a matching method between domain ontology and existing RDBMS tables for semantic retrieval. In the processing of extracting a local ontology, some problems such as losing domain in formation can occur since the correlation of domain ontology has not been considered at all. To prevent these problems, we propose an instance-based matching which uses relational information between RDBMS tables and relational information between classes in domain ontology. To verify the efficiency of the method proposed in this paper, several experiments are conducted using the digital heritage information currently serviced in the countrywide museums. Results show that the proposed method increase retrieval accuracy in terms of user relevance and satisfaction.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.405-415
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• 1999

웹의 성장은 점차 복잡한 응용에 대한 요구를 가중시켰으며, 데이타베이스와 웹과의 효율적인 연동 역시 중요한 문제가 되었다. 본 논문에서는 이와 같은 환경을 효율적으로 지원하기 위한 웹 응용 서버 WATS를 설계하고 구현하였다. WATS에서 응용 프로그램은 컴포넌트 단위로 작성된 후 동적으로 링크되고 요청을 처리할 응용 서버가 대기 상태로 존재하는 확장 API 응용 서버 방식으로 구현되었으며, 이러한 웹 서버와 응용 서버의 분리 구조는 대량의 요청을 처리하기에 적합하다. 또한 컴포넌트를 특성에 따라 분류한 후 각 특성에 적합한 특성 기반 스케줄링 알고리즘을 적용하여 프로세스 부하 균형을 이루었으며, 이 기법이 일반적인 라운드 로빈 스케줄링 알고리즘보다 좋은 성능을 나타냄을 성능 측정을 통해서 보인다.Abstract The increasing popularity of the World-Wide-Web (WWW) has resulted in demand for more complex applications, and web gateways to database became core component in such applications. In this paper, we have designed and implemented WATS in order to support these environments. In WATS, application components are dynamically linked with application server processes. And it is implemented as extensible API application server architecture and is able to process a large amount of requests through separating web server from application server. Also we classify the components into various categories according to its own properties and devise process load balancing algorithm by using property-based scheduling. We show WATS using this algorithm performs better than those using general round-robin algorithm.

• Journal of Power Electronics
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• v.2 no.4
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• pp.250-257
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• 2002

This paper introduces the Interactive Power Electronics Seminar - iPES - a new software package for teaching of fundamentals of power electronic circuits and systems. iPES is constituted by HTML text with Java applets for interactive animation, circuit design and simulation and visualization of electromagnetic fields and thermal issues in power electronics. It does comprise an easy-to-use self-explaining graphical user interface. The software does need just a standard web-browser, i.e. no installations are required. iPES can be accessed via the World Wide Web or from a CD-ROM in a stand-alone PC by students and professionals. Due to the underlying software technology iPES is very flexible and could be used for on-line learning and could easily be integrated into an e-learning platform. The aim of this paper Is to give an introduction to the iPES-project and to show the different areas covered. The e- learning software is available at no costs at $\underline{www.ipes.ethz.ch}$ in English, German, Japanese, Korean, Chinese and Spanish. The project is still under development and the web page is updated in about 4 weeks intervals.

• The KIPS Transactions:PartB
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• v.16B no.1
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• pp.85-92
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• 2009

As World Wide Web is more popularized nowadays, the environment is flooded with the information through the web pages. However, despite such convenience of web, it is also creating many problems due to uncontrolled flood of information. The pornographic, violent and other harmful information freely available to the youth, who must be protected by the society, or other users who lack the power of judgment or self-control is creating serious social problems. To resolve those harmful words, various methods proposed and studied. This paper proposes and implements the protecting system that it protects internet youth user from harmful contents. To classify effective harmful/harmless contents, this system uses two step classification systems that is harmful word filtering and SVM learning based filtering. We achieved result that the average precision of 92.1%.

• Annual Conference of KIPS
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• 2009.11a
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• pp.417-418
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• 2009

웹이 대중화되면서, 사용자 계층도 어린이, 노인, 장애인 등으로 다양해졌다. 인지적, 신체적 특징에 상관없이 모든 사람에게 동등한 웹 기회를 제공하고 있는가를 나타내는 지표가 웹 접근성이다. 웹 사이트들이 특정 수준의 웹 접근성을 준수하도록 유도하기 위해 W3C(World Wide Web Consourtium)의 WAI(Web Accessiability Initiative)는 웹 콘텐츠 접근성 가이드라인 WCAG (Web Content Accessibility Guideliens)를 개발하였다. 현재, WCAG2.0까지 발표된 가이드라인은, 4개의 원칙(Principle), 12개의 지침(Guideline), 그리고 61개의 성공기준(Success Criteria)으로 구성 되어 있다. 평가자들은 WCAG2.0에서 제시하는 성공 기준에 맞춰, 웹 사이트가 웹 접근성을 어느 수준으로 준수하고 있는지 평가한다. 하지만, WCAG2.0을 기준으로 웹 사이트를 평가할 경우, 성공기준의 준수여부는 평가가 가능하지만, 특정 사용자 집단의 특성을 반영한, 우선순위가 포함되지 않아, 특정 사용자 집단을 위한 개선 사항을 도출하는데 어려움이 있다. 이에, 본 논문에서는 이러한 점을 고려하여 WCAG2.0 기반의, 특정 사용 집단을 위한 웹 접근성 평가 모델을 제안한다. 사용자 특성에 따라 성공지침들의 중요도가 달라 질 수 있으므로, AHP 기법을 활용하여 성공지침들의 상대적 중요도를 평가하고, 우선순위화 하였다. 평가 모델의 효용성을 입증하기 위해, 특정 사용집단으로 노인 집단을 선정하여, 웹 접근성 평가 모델을 개발하였다.

• Journal of KIISE:Software and Applications
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• v.26 no.8
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• pp.946-954
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• 1999

웹의 등장으로 전자 업무 처리는 급격한 성장을 보여왔다. 많은 업계에서는 업무 처리에 있어 핵심이 되는 트랜잭션을 웹에서 처리하기 위한 시스템 개발에 많은 노력을 기울여왔다. 그러나 대부분의 웹 트랜잭션 연구는 주로 CGI 방식의 트랜잭션 처리 성능의 한계를 극복하거나, 여러 HTTP 요청간의 상태 유지 방법 또는 시스템의 확장성 등에 대해 연구가 집중된 반면, 부적합한 웹 환경으로 유발되는 시스템의 일관성 손실에 대해서는 많은 관심을 받지 못했다.본 논문에서는 웹 상에서 신뢰성 있는 트랜잭션을 처리하는 경우 발생되는 세 가지 문제점을 지적하고, 이를 막기 위해 웹 트랜잭션 처리 시스템인 WebTP에서 제공하는 해결책을 제안한다. 제안한 해결책은 쿠키 로깅, 웹 페이지 로깅, 그리고 일방적으로 철회된 트랜잭션의 상태를 유지하는 기법을 근간으로 한다. 또한 제안된 방법은 유사 구조의 타 웹 트랜잭션 처리 시스템에서도 적용 가능하다.Abstract Electronic business processing has drastically grown since the advent of the World Wide Web. As transaction processing is at heart of business processing, many companies have been interested in transaction processing on the Web. However, little attention has been paid to supporting consistent transaction processing on the Web, while most of the work has been focused on performance enhancement, processing multiple HTTP requests in a single context, and scalability.This paper identifies three problems in consistent transaction processing on the Web, and proposes corresponding solutions for each problem. The results are implemented in the Web transaction processing system WebTP. These solutions are based on cookie logging, Web page logging and keeping information for unilaterally aborted transactions. The solutions proposed in this paper also can be applied to other Web transaction processing system of similar architecture.

• Journal of KIISE:Information Networking
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• v.28 no.2
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• pp.229-235
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• 2001

With the explosive popularity of the World Wide Web, the low penonnance of network often leads web clients to wait a long time for web server's response. To resolve this problem, web caching (proxy) has been considered as the most efficient technique for web server to handle this problem. The placement of web proxy is critical to the overall penonnance, and Li et al. showed the optimal placement of proxies for a web server in the internet with the linear and tree topology when the number of proxies, ]M, is given [4, 5]. They focused on minimizing the over all access time. However, it is also considerable for target web server to minimize the total number of proxies while each proxy server guarantees not to exceed certain res(Xlnse time for each request from its clients. In this paper, we consider the problem of finding the optimal number and placement of web proxies with the lin~ar and tree topology under the given threshold cost for delay time.