• Asia pacific journal of information systems
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• 제6권1호
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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.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.488-493
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• 2003

This paper presents new skill in tube-mill processing getting the increase in production efficiency and quality in response to the recent request of high grade pipe. In this study, researchers developed the method to improve the precision of pipe and tool life in tube-mill processing. Optimum tool shape is devised by analyzing various simulation and mechanism in cutting process. In order to verify the confidence of the proposed machining technology, it is applied to the real processing machinery in the field.

• 대한조선학회논문집
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• 제47권4호
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• pp.606-612
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• 2010

This study took advantage of NC processing technique in order to recreate design in development process of leisure boat based on the Korean boats and ships. CNC milling is an area which is concerned in automation process of boat production and needs sophisticated software, equipment and professionals to pilot it. The progress of manufacture begins when the surface model creation and simulation being done using CAD/CAM software. In this process, the needs such as 3D design, NC processing data, plug lamination and partition processing appear as detailed steps. The study completed these detailed steps and also the application example has been studied with presenting engineering potentialities.

• KCI Concrete Journal
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• 제12권2호
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• pp.3-10
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• 2000

A computer program, named NEO-PCBRG, for the analysis and design of prestressed con-crete(PSC) bridges was developed using the finite element method. NEO-PCBRG can predict the response of PSC bridges throughout the various stages of construction and service. NEO-PCBRG has both pre- and post-processing capabilities. Pre-processing refers to all the neces- sary steps required to prepare a virtual prototype, more commonly termed a varied model for analysis. Post-processing here stands for the step in which the results from the analysis are reviewed and interpreted. In order to allow for the easy and convenient execution of the entire procedure, NEO-PCBRG was developed using computer graphics in the Visual Basic pro- gramming language. In conclusion, this study presents a new software architecture for analy-sis using the user-oriented design technique.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.295-295
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• 2000

In this paper, the measurement algorithm of PCB alignment error is developed using image processing. The X-Y-$\theta$ table correcting PCB alignment error is driven by drive module based on microprocessor according to calculation results obtained through image processing procedure. In order to recognize the X-Y-$\theta$ position errors, two fiducial points are marked on PCB and two cameras of ultraviolet rays types are used for detection of the points to capture exactly fiducial points under disturbance of illumination change. Through application for a practical screen printer, the precision control using the developed position control system can be realized about 2.5${\mu}{\textrm}{m}$ in table moving range and 8${\mu}{\textrm}{m}$ in camera processing precision.

• 소성∙가공
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• 제19권5호
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• pp.320-324
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• 2010

Multi-Layer Ceramic Circuit(MLCC) in the face of thousands of fine pitch multi hole is processed. However, the fine pitch multi hole has a size of only a few micrometers. Therefore, in order to curtail the measurement time and reduce error, the image processing measurement method is required. So, we proposed an image processing measurement algorithm which is required to accurately measure the fine pitch multi hole. The proposed algorithm gets image of the fine pitch multi hole, extracts object from the image by morphological process, and extracts the parameters of its position and feature by edge detecting process. In addition, we have used the sub-pixel algorithm to improve accuracy. As a result, the proposed algorithm shows 97% test-retest measurement reliability within 2 ${\mu}m$. We found that the algorithm was wellsuited for measuring the fine pitch multi hole.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권5호
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• pp.877-895
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• 2010

The state-of-the-art techniques of storing XML data, modeled as an XML tree, are node-based in the sense that they are centered around XML node labeling and the storage unit is an XML node. In this paper, we propose a generalization of such techniques so that the storage unit is an XML subtree that consists of one or more nodes. Despite several advantages with such generalization, a major problem would be inefficiency in XPath processing where the stored subtrees are to be parsed on the fly in order for the nodes inside them to be accessed. We solve this problem, proposing a technique whereby no parsing of the subtrees involved in XPath processing is needed at all unless they contain the nodes of the final query result. We prove that the correctness of XPath processing is guaranteed with our technique. Through implementation and experiments, we also show that the overhead of our technique is acceptable.

• 한국레이저가공학회지
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• 제4권2호
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• pp.29-38
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• 2001

A development of in-process and reliable monitoring system in laser materials processing is essential for successful applications toward the real industrial fields. It was known that optical signals induced by laser-matter interactions provide a good indication not only to monitor various defects but also to characterize and identify the process However there are still difficulties to implement the optical monitoring system in real fields since the system is susceptible to the spurious change of the signal affected by the variation of experimental conditions and environmental noises. In this article. a new type of optical monitoring technique named 'chromatic modulation technique' is described as a reliable, robust and sensitive monitor for the applications in laser materials processing in order to tackle the conventional problems in optical system.

• 한국컴퓨터정보학회논문지
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• 제8권1호
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• pp.1-6
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• 2003

능동규칙의 조건부 평가는 사건이 발생할 때마다 수행되기 때문에 조건부 처리 방법에 따라 시스템의 성능에 중요한 영향을 미친다. 그래서 능동 데이터베이스의 성능 향상을 위해 능동규칙의 조건부에 관한 연구가 매우 중요한 요소가 되며. 조건부에서 발생되는 연산 처리시간을 최소화 시켜야만 시스템의 성능을 높일 수 있다. 본 논문에서는 조인연산과 선택연산을 효율적으로 처리할 수 있는 트리 처리 시스템을 제안한다. 실험 결과 본 논문에서 제안한 트리 처리 시스템은 기존의 조건부 평가 방법보다 능동규칙의 조건부 처리에 대한 평가비용이 적게 소요됨을 알 수 있다.

• 산업경영시스템학회지
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• 제32권2호
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• pp.85-93
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• 2009

GOMS model is a cognitive modeling method of human performance based on Goal, Operators, Methods, Selection rules. GOMS model was originally designed for desktop environment so that it is difficult for GOMS model to be implemented into the mobile environment. In addition, GOMS model would be inaccurate because the original GOMS model was based on serial processing, excluding one of most important human information processing characteristics, parallel processing. Therefore this study was designed to propose a modified GOMS model including mobile computing and parallel processing. In order to encompass mobile environment, an operator of 'look for' was divided into 'visual move to' and 'recognize' whereas 'point to' and 'click' were combined into 'tab.' The results showed that newly introduced operators were necessary to estimate more accurate mobile computing behaviors. In conclusion, modified-GOMS model could predict human performance more accurately than the original GOMS model in the mobile computing environment.