• Journal of the Society of Naval Architects of Korea
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• v.29 no.1
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• pp.1-13
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• 1992

The objective of this study is to develop knowledge-based system for the preliminary design and midship section design of bulk carrier and to enhance the applicability of knowledge engineering in the field of Naval Architecture. First, expert system shell called E.1 is developed in C language. E.1 supports backward-chaining, automatic iteration procedure and reiterative inference mechanism for efficient application of knowledge-based system in structural design. Knowledge representation in E.1 includes IF-THEN rules, 'facts'and 'tables'. Second, knowledge bases for the principal particulars and midship section design are developed by experimental formula, design standard and experiential knowlege. Third, hybrid system combined this knowledge-based system with the optimization program of midship section is developed. Finally, the simplified design method utilizing the regression analysis of the optimum results of stiffened plate is developed for facilitating the design process. Using this knowledge-based system, the design process and results for Bulk carrier and stiffened plates are discussed. It is concluded that knowledge-based system is efficient for preliminary design and midship section design of the ship. It is expected that the performance of the CAD system would be enhanced if the better knowledge-base is accumulated in the E.1 tool.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.65-72
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• 2000

The study investigated the effects of base curve radius art the fit of thin, mid-water contact lenses. It was found that central corneal curvature(as measured with the keratometer) was not predictive of the best fitting base curve. Proper lens fit may be the single most important factor that ultimately determines the success of contact lens wear. Comfort, vision, and physiological response are all dependent on the fit of the lens. The percent of optimal fits was highest with the 8.4 mm base curve lens for all three ranges of keratometry values. When fit with the 8.4 mm lens. For most eyes, fitting a flatter lens led to greater decentration, decreased comfort, and no increase in lens movement. The 8.4 mm lens was found to provide on "optimal" fit in over 60% of eyes tested and a fit of "good" or "better" in nearly 90% of eyes tested. Comparisons of different manufactures' lens found that similiar lenses do not always fit in the same way due to subtle design and production differences. Therefore, different products may require different base curve radii to fit the same patient. This is even true when water content, center thickness, and diameter are approximately the same. A praditioner fitting a new patient in this lenses should begin with the 8.4 mm base curve radius.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.747-754
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• 2004

Database administrators should be aware of performance characteristics of database systems in order to manage database system effectively. The usages of system resources in database systems could be quite different under database workloads. The objective of this paper is to identify and analyze performance characteristics of database systems in different workloads, which could help database tuners tune database systems Under the TPC-C and TPC-W workloads, which represent typical workloads of online transaction processing and electronic commerce respectively, we investigated usage types of resource that are determined by fourteen performance indicator, and are behaved in response to changes of four tuning parameters (data buffer, private memory, I/O process, shared memory). Eight out of the fourteen performance indicators cleary show the performance differences under the workloads. Changes of data buffer parameter give a influences to database system. The tuning parameter that affects the system performance significantly is the database buffer size in the both workloads.

• Journal of the Korea Society of Computer and Information
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• v.14 no.1
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• pp.107-115
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• 2009

The cryptological key which is used in WiMAX environment is used at regular intervals by mobile nodes (laptop computer, PDA, cell-phone) which is in the range of base station coverage. But it is very weak at local attack like man-in-the-middle when the mobile node is off the range of base station or enters into the range to communicate with base station because the communication section is activated wirelessly. This paper proposes a distribution key building protocol which can reuse security key used by nodes to reduce cryptological security attack danger and communication overhead which occurs when mobile node tries to communicate with base station. The proposed distribution key establishing protocol can reduce overhead which occurs between base station and mobile node through key reusing which occurs during the communication process and also, makes security better than IEEE 802.16 standard by creating shared key which is required for inter-certification through the random number which node itself creates.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1998.10a
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• pp.229-238
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• 1998

본 논문에서는 최근 대두되고 있는 웹사이트의 관리 문제를 위하여, 웹사이트 /베이스 관리시스템의 기능을 웹 사이트 생명주기와 웹 관련자의 관점에서 분석하였으며 , 상업용과 연구용 웹 사이트/베이스 관리 시스템과 비교하여, 부족한 기능을 보완하기 위하여 시스템 행위의 감시 및 문제를 감지하여 필요한 조치를 취할 수 있는 Active Module을 제안하였다.

• Computational Structural Engineering
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• v.8 no.4
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• pp.4-16
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• 1995

본 고에서는 지식베이스엔지니어링이 기존의 제품개발 방법론을 개선하기 위한 지능적인 설계도구로서 컴퓨터를 사용하는 새롭고 흥미로운 대안임을 살펴보았다. 전문가의 설계 및 현장 경험을 조직적이고 체계적으로 수집하여 활용하는 것은 동시공학(Concurrent Engineering) 방법론의 실행을 위한 도구로서 매우 중요함을 살펴보았다. 또한 시스템의 효과적인 구축을 위해 어떤한 것들을 고려해야 하는지도 살펴보았다. 이러한 일련의 과정을 통해 설계 분야가 미약한 국내 환경에 지식베이스엔지니어링이 하루 속히 정착되기를 희망한다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.873-882
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• 1998

The parallel database machine approach is currently widely and successfully used. There are four major architectures which are used in this approach: shared-nothing architecture, shared-evertying architecture, shared-disk architecture, and hybrid architecture. In this paper, we use an analytical model to evaluate the performance of these database machine architectures. We define an abstract model for each type of database machine design to obtain performance equatons describing the execution times with respect to the hybrid hash join poeration. Using the performance equations, we evaluate the execution times of the various database machine design models.

• Journal of the Korean Society for information Management
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• v.4 no.1
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• pp.24-46
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• 1987

The recent growth of full-text database operations has brought new opportunities for subject access. The fundamental problem of subject access in the online environment is the indexing language and technology. The purpose of this paper is to identify the characteristics and capabilities of full-text retrieval as compared to traditional bibliographic retrieval. Retrieval performance of indexing languages, full-text systems features achieved so far, and the new role of a controlled vocabulary, are examined. This paper also includes a review of the research on full-text retrieval performance.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09b
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• pp.17-20
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• 2003

언어는 인간의 지적 활동의 가장 근본적인 도구이다. 컴퓨팅에 있어서도 특히, 인간의 지적 활동을 모방하는 경우에 언어를 통한 컴퓨팅이 효과적일 수 있다. 의미베이스는 시스템 기능문법(SFLT)을 기반으로 한 인간 사고의 모델링으로 언어기반 컴퓨팅의 도구로 이용될 수 있다 본 논문에서는 카네비게이션 시스템을 예로 들어 언어를 매개로 한 지적 컴퓨팅에 관한 아이디어를 제시한다. 의미베이스의 계층은 컨텍스트, 의미, 어휘문법으로 나뉘고, 각 계층은 시스템, 서브시스템, 인스턴스로 세분된다 본 논문에서는 카네비게이션의 컨텍스트를 정의하고, 이것을 바탕으로 의미층에서 의미를 생성함을 보인다 그리고, 제시한 의미베이스 안에서 대화를 분석 및 생성하는 과정을 통해 컴퓨팅이 이루어질 수 있음을 예를 통하여 보인다.

• The Transactions of the Korea Information Processing Society
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• v.3 no.4
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• pp.745-756
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• 1996

In this paper, the design and implementation of VODS is described. VODS is an object-oriented database de-sign support system. VODS supports the whole database design steps according to the EOMT(extended OMT). EOMT as an object- oriented database design methodology is deviced by extending the object model of OMT(Object Modeling Technique) for supporting information navigations to manipulate hyperemia objects. Database designers can do the whole design steps by clicking mouse buttons on the appropriate icons or commands from the initial screen mode.