• Proceedings of the KSR Conference
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• 2002.05a
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• pp.392-398
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• 2002

In this paper, an engineering database management system(EDMS) has been developed to support the system engineering for design of the high speed titling train to be put into the conventional lines. The developed system can be operated on client-server or web circumstances. To accomplish the concurrent engineering in design of the rolling stocks, this system has been fully equipped with a powerful viewer and a postprocessor for 3D CAD data or FE results. The system was tested using the engineering data produced during carrying out the G7 project to design KHST(Korean High Speed Train) in a crashworthy viewpoint. Through this example, it is shown that the system should be powerfully applied to improving the performance of the system engineering.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.225-229
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• 2004

현재 인터넷에서 사용하고 있는 네트워크 계층 프로토콜은 IP 버전 4 인데, 이러한 주소 부족 문제를 해결하고자 IP 주소 필드의 길이가 대폭 확장되는 IPv6 라는 새로운 인터넷 프로토콜을 개발하게 된다(5). 그러나 이러한 신 표준안을 인터넷에 실제로 적용하고 운영하기에는 많은 어려운 문제들이 남아있어 그 대안으로 NAT(Network Address Translation)[1]가 등장하게 된다. 그러나 이러한 NAT 기능은 외부 망으로부터의 접촉이 불가능하다는 특성을 가지고 있다. 이러한 특성은 보안 유지측면에서는 장점으로 작용하나, 소규모 기업이나 사무실이 웹(Web) 서버(Server) 나 메일(mail) 서버등을 두고 싶어하는 경우에는 외부에서의 접근이 허용되어야 하므로 단점이 된다. 본 연구에서는 이러한 단점을 파악하기 위하여 NAT 테이블(table) 에 수정을 가함으로써 사설망내부의 특정 서버에 접근할 수 있는 확장된 개념의 NAT를 제안하고자 한다. 아울러 이러한 NAT 기능을 이용하여 구성된 사설망 간의 연결기능을 제공할 수 있는 방법을 제안함으로써 기존의 가상 사설망(VPN : Virtual Private Network) 외 일부 기능도 수용할 수 있도록 하였다.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.61-64
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• 1996

Currently many researches are going on a Picture Archiving and Communication System (PACS) which can handle a large number of image data very efficiently. However, the price of those systems are very expensive to a small and medium hospital. In this paper, we developed a PC based Mini-PACS at a low price with a high performance. The main components of the designed system are: Image processing and display for a diagnosis, Client/Server database management system, Multi-monitor display system, Connection through the World Wide Web with Common Gateway Interface.

• Annual Conference of KIPS
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• 2018.10a
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• pp.2-4
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• 2018

본 연구에서는 웹 서버 성능 테스트 프로그램인 JMeter를 이용하여 대표적인 오픈소스 웹 서버인 Apache, Nginx, Cherokee, Monkey HTTP, Sand Storm의 성능을 비교 분석하였다. 실험 결과 파일 크기가 작은 경우에는 Lighttpd, 중간 크기인 경우에는 Cherokee, 큰 경우에는 Nginx가 좋은 성능을 보였다. 또한 클라이언트의 수를 증가시켰을 때 Cherokee가 상대적으로 가장 작은 성능 저하를, Lighttpd가 가장 큰 성능 저하를 보였다.

• Annual Conference of KIPS
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• 2008.05a
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• pp.589-592
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• 2008

최근 대부분의 기업은 인터넷 웹 서비스를 하고 있고, 대부분의 인터넷 사용자들이 여러 종류의 웹 서비스를 제공받고 있다. 하지만 사용자들이 필요로 하는 서비스는 한정되어 있지만 대부분의 기업에서는 여러 가지 서비스를 제공하여 다양한 많은 사용자들의 요구를 수용하고자 한다. 그로 인해 초기 메인 웹 페지이에 많은 링크가 연결된 페이지를 제공하게 된다. 이는 초기 웹페이지의 로딩에 있어 큰 용량의 소스가 원인이 되어 다수의 사용자가 짧은 시간에 접속할 경우 서비스 오류의 원인이 되기도 한다. 또한 대부분의 사용자들이 필요로 하는 몇 개의 링크 기능만을 제공하고 니즈가 적은 링크 기능은 비활성화 함으로써 사용자 요구에 좀 더 빠르게 대응할 수 있도록 링크 맵 프로그램을 이용한 웹 시스템을 제안하고 웹 서버의 성능 향상을 연구한다.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3088-3096
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• 1997

In this paper, we present WWW system over native ATM services. The use of native ATM services through ATM API can provide better performance and functionality than that of IP over ATM, LAN Emulation or Multiprotocol over ATM. Our WWW browser and server provide advanced WWW services based on enhanced performance and guaranteed QoS support by using native ATM service benefits. This paper describes and compares advantages and disadvantages of Native ATM Services and ATM Internet Services, and addresses ATM API standardization and development trend that are made by the ATNI Forum for the support of native ATM services, and then describes the architecture and operation of our WWW browser and server using ATM API. The system architecture is based on HTTP over ATM API capable of supporting guaranteed QoS over its connections. The system defines and uses new HTML attributes within hyperlinking HTML elements for the description of ATM QoS and traffic characteristics that are derived from UNI signaling 3.1 connection characteristics information elements. Our system uses WinSock 2 API as its ATM API.

• Convergence Security Journal
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• v.17 no.5
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• pp.3-10
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• 2017

Standard Protocol Optimized for Resource-Constrained IoT Environment Constrained Application Protocol (CoAP) supports web-based communication between a sensor node in the IoT environment and a client on the Internet. The CoAP is a Request / Response model that responds to the client's CoAP Request message by responding with a CoAP Response message from the server. CoAP recommends the use of CoAP-DTLS for message protection. However, validation of the use of DTLS in the IoT environment is underway. We analyze CoAP and DTLS security mode, evaluate performance of secure channel creation time, security channel creation step time, and RAM / ROM consumption through Cooja simulator and evaluate the possibility of real environment application.

• Journal of Internet Computing and Services
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• v.17 no.5
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• pp.89-95
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• 2016

In a software testing domain, test case prioritization techniques improve the performance of regression testing, and arrange test cases in such a way that maximum available faults be detected in a shorter time. User-sessions and cookies are unique features of web applications that are useful in regression testing because they have precious information about the application state before and after making changes to software code. This approach is in fact a user-session based technique. The user session will collect from the database on the server side, and test cases are released by the small change configuration of a user session data. The main challenges are the effectiveness of Average Percentage Fault Detection rate (APFD) and time constraint in the existing techniques, so in this paper developed an intelligent framework which has three new techniques use to manage and put test cases in group by applying useful criteria for test case prioritization in web application regression testing. In dynamic weighting approach the hybrid criteria which set the initial weight to each criterion determines optimal weight of combination criteria by evolutionary algorithms. The weight of each criterion is based on the effectiveness of finding faults in the application. In this research the priority is given to test cases that are performed based on most common http requests in pages, the length of http request chains, and the dependency of http requests. To verify the new technique some fault has been seeded in subject application, then applying the prioritization criteria on test cases for comparing the effectiveness of APFD rate with existing techniques.

• Journal of Internet Computing and Services
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• v.6 no.4
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• pp.59-73
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• 2005

Caching query results and reusing them in processing of subsequent queries is an important query optimization technique. Materialized view and view indexing are the representative examples of such a technique. The two schemes had received much attention for relational databases, and have been investigated for XML data since XML emerged as the standard for data exchange on the Web. In XML view indexing, XML view xv which is the result of an XML query is represented as an XML view index(XVI), a structure containing the identifiers of xv's underlying XML elements as well as the information on xv. Since XVI for xv stores just the identifiers of the XML elements not the elements themselves, when xv is requested, its XVI should be materialized against xv's underlying XML documents. In this paper, we address the problem of integrating an XML view index management system with an RDBMS based XML storage system. The proposed system was implemented in Java on Windows 2000 Server with each of two different commercial RDBMSs, and used in evaluating performance improvement through XML view indexing as well as its overheads. The experimental results revealed that XML view indexing was very effective with an RDBMS based XML storage system while its overhead was negligible.

• Smart Media Journal
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• v.12 no.2
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• pp.66-75
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• 2023

Recently, the number of cloud web applications is increasing owing to the accelerated migration of enterprises and public sector information systems to the cloud. Traditional network attacks on cloud web applications are characterized by Denial of Service (DoS) attacks, which consume network resources with a large number of packets. However, HTTP DoS attacks, which consume application resources, are also increasing recently; as such, developing security technologies to prevent them is necessary. In particular, since low-bandwidth HTTP DoS attacks do not consume network resources, they are difficult to identify using traditional security solutions that monitor network metrics. In this paper, we propose a new detection model for detecting HTTP DoS attacks on cloud web applications by collecting the application metrics of web servers and learning them using machine learning. We collected 18 types of application metrics from an Apache web server and used five machine learning and two deep learning models to train the collected data. Further, we confirmed the superiority of the application metrics-based machine learning model by collecting and training 6 additional network metrics and comparing their performance with the proposed models. Among HTTP DoS attacks, we injected the RUDY and HULK attacks, which are low- and high-bandwidth attacks, respectively. As a result of detecting these two attacks using the proposed model, we found out that the F1 scores of the application metrics-based machine learning model were about 0.3 and 0.1 higher than that of the network metrics-based model, respectively.