• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 봄 학술발표회 논문집
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• pp.249-256
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• 2002

A new optimization procedure with approximate reanalysis module, using the staged hybrid methods with substructuring, is proposed in is study. In this procedure, displacements are calculated with two step mixed procedures. First step is to introduce the conservative approximation, which is a hybrid form of the linear and reciprocal approximation, as local approximation. In the next step, it is combined with the global approximation by reduced basis approach. The quality of reanalyzed quantities can be greatly improved through these staged hybrid approximations, specially for large changes in the design. Overall procedures are based on substructuring scheme. Several numerical examples illustrate the validity and effectiveness of the proposed methods.

• 대한산업공학회지
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• 제24권3호
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• pp.359-365
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• 1998

An economic process monitoring procedure is presented when the major quality characteristic of the item is dichotomous. Every item is inspected and decided whether it is conforming or not. If an item is found to be nonconforming, the previous number of the successive conforming items is compared with a predetermined number r to check the process for existence of any assignable cause of variation. A cost model is constructed on the basis of costs of inspection, illegal signal, undetected out-of-control state and corrective action. By minimizing the expected total cost per unit time, the optimal value of r is obtained. The effects of cost coefficients are studied numerically.

• 산업공학
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• 제20권2호
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• pp.94-102
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• 2007

Portfolio management deals with decision making on 'when' and 'how' to revise an existing portfolio. In this paper, we show that a classical statistical process control (SPC) chart for normal data, a wellestablished tool in quality engineering, can effectively be used for signaling times for revising a portfolio. Noting that the day-to-day performance of a portfolio may be auto-correlated, we use the exponentially weighted moving average center-line chart to develop an automatic portfolio management procedure. The portfolio management procedure is extensively tested on historical data of equities traded in the Korea Exchange (KRX), the American Stock Exchange (AMEX), and the New York Stock Exchange (NYSE). In comparison with the performances of the KOSPI, XAX, and NYA indices during the same time periods, results from these experiments show that SPC chart-based portfolio revision presents itself a convenient and reliable method for optimally managing portfolios.

• Communications for Statistical Applications and Methods
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• 제17권3호
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• pp.319-326
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• 2010

In this paper, a new group sampling plan for the lot acceptance is proposed for the time truncated life test, which can be utilized when multi-item testers are implemented. The design parameters are found using the two-point approach such that the producer's and consumer's risks are satisfied simultaneously at the acceptable reliability level and the lot tolerance reliability level, respectively. The case of Weibull distribution is described to illustrate the procedure that can be used when the quality level is expressed by a multiple of the specified life. The advantage of the proposed plan is demonstrated by comparing with the existing plan in terms of the sample size required. The tables are constructed and some examples are given to illustrate the procedure developed here.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1410-1413
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• 2009

A city development has been focused on solving a housing shortage of city resulted from rapid industrialization and population increase in city. However, such a development has caused many problems in environment, economy, safety, and so on. In recent, therefore, a new paradigm of a city development is required, and thus ubiquitous city (U-City) concept appears. U-City development, which combines construction method and IT technique, creates a new composite space, and help people improve quality of life in terms of solving many problems caused by existing method of a city development. However, there is no guide to build U-City up to date, and most present U-City projects have processed following past method of city development. Therefore, an objective of this paper is to suggest an explicit procedure of enforcement design in U-City system.

• Advances in concrete construction
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• 제16권2호
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• pp.91-96
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• 2023

The present work provides a new solution to both the correct execution and quality control of straight thread couplers for reinforcing bars under monotonic loading conditions. A random survey on already constructed couplers together with a new mechanical model, adjusted with an experimental campaign, led us to present this new procedure in reinforced concrete construction. Formulation and methodology for a correct placement of straight thread couplers is presented.

• 품질경영학회지
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• 제44권4호
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• pp.713-733
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• 2016

Purpose: The primary objective of this case study is to establish a COQ(Cost of Quality) management system for power generation industries. Key topics of this study include collecting COQ elements, their classifications, COQ computation formula, and determining COQ improvement projects. Results: A comprehensive set of COQ elements have been isolated for electric power generation companies. The COQ elements were classified in such a way that they could be managed according to the PAF model as well as the SIPOC diagram. This study showed that a systematic approach could be established for monitoring the COQ elements and using them in the process of improving quality competitiveness. Methods: The PAF(Prevention-Appraisal-Failure) model has been employed in the process of collecting COQ elements for a power generation company. All the cost of quality elements were first examined through an extensive review of articles and books in the field of quality. The cost elements were then refined and augmented by conducting a comparative study with international standards. The COQ elements have been verified by a group of quality managers and classified according to both the PAF model and the SIPOC diagram for better understanding in the entire organization. An improvement strategy has been also proposed by using a typical COQ level of power generation companies. Conclusion: The conventional PAF model was used in establishing a COQ management system for power generation industries. This case study illustrates the procedure about identification, classification and computation of quality costs, including selection of improvement projects. The system can be used not only for observing the current state of cost elements related to quality, but also for planning an improvement strategy using the ratio of cost classification.

• 대한토목학회논문집
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• 제33권1호
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• pp.61-70
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• 2013

본 논문은 통계적 품질관리 기법을 활용하여 건전한 교량의 고유진동수비와 응답비 관리범위를 찾고, 그에 준거한 응답보정 방법을 제시하였다. 이를 위해 본 연구는 재하 시험 및 해석으로부터 도출된 구조형식별 정 동적 응답 특성에 대한 기술통계분석, 정규성 검정, 분산분석 등을 수행하였다. 제안된 방법은 실제 진단 사례에 근거하고 통계적 품질관리 기법을 활용함으로써 응답보정 및 내하력 평가를 위한 과학적 기준과 체계적 절차를 제공할 수 있을 것으로 기대한다.

• 융합보안논문지
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• 제12권6호
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• pp.93-99
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• 2012

웹 애플리케이션 개발이 보편화됨에 따라 대부분의 소프트웨어는 개발기간 단축, 에러없는 품질, 수시 유지보수에 대한 적응성, 거대하고 복잡한 소프트웨어의 필요성 등과 같은 과제가 제기되었다. 웹 애플리케이션 개발시 이러한 품질문제에 대응하기 위해 소프트웨어의 재사용성, 신뢰성, 확장성, 단순성 등과 같은 측면을 고려하지 않을 수 없는 환경으로 변화 되었다. 이같은 상황에서 전통적 개발방법론으로는 보안품질을 해결하는데 한계를 가지고 있기 때문에 품질에 기반한 시큐어코딩 방법론이 필요하다. 웹 애플리케이션 보안품질은 애플리케이션 로직, 데이터, 아키텍처 전체 영역에서 별도의 방법론으로 대처하지 않으면 목표를 달성할 수 없다. 본 연구는 시큐어코딩의 최대 현안인 웹 애어플리케이션 개발을 위하여 웹 애플리케이션 아키텍쳐 설계절차를 제안한다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1998년도 제15회 음성통신 및 신호처리 워크샵(KSCSP 98 15권1호)
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• pp.142-147
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• 1998

Recently, 8 kb/s CS-ACELP coder of G.729 is atandardized by ITU-T SG15 and it has been reported that the speech quality of G729 is better than or equal to that of 32kb/s ADPCM. However G.729 is the fixed rate speech coder, and it does not consider the property of voice activity in mutual conversation. If we use the voice activity, we can reduce the average bit rate in half without any degradations of the speech quality. In this paper, we propose an efficient variable rate algorithm for G.729. The variable rate algorithm consists of two main subjects, the rate determination algorithm and algorithm, we combine the energy-thresholding method, the phonetic segmentation method by integration of various feature parameters obtained through the analysis procedure, and the variable hangover period method. Through the analysis of noise features, the 1 kb/s sub rate coder is designed for coding the background noise signal. So, we design the 4 kb/s sub rate coder for the unvoiced parts. The performance of the variable rate algorithm is evaluated by the comparison of speed quality and average bit rate with G.729. Subjective quality test is also done by MOS test. Conclusively, it is verified that the proposed variable rate CS-ACELP coder produced the same speech quality as G.729, at the average bit rate of 4.4 kb/s.