• 한국시뮬레이션학회논문지
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• 제8권3호
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• pp.1-16
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• 1999

This paper deals with a discrete simulation optimization method for designing a complex probabilistic discrete event system. The proposed algorithm in this paper searches the effective and reliable alternatives satisfying the target values of the system to be designed through a single run in a relatively short time period. It tries to estimate an autoregressive model, and construct mean and confidence interval for evaluating correctly the objective function obtained by small amount of output data. The experimental results using the proposed method are also shown.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1993-1998
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• 2004

This paper proposes a new framework for control system design, called the data-based control approach or data space approach, in which the input and output data of a dynamical system is directly and solely used to analyze or design a control system without the employment of any mathematical models like transfer functions, state space equations, and kernel representations. Since, in this approach, most of the analysis and design processes are carried out in the domain of the data space, we introduce some notions of geometrical objects, e.g., the openloop and closed-loop data spaces, which serve as the system representations in the data space. In addition, we establish a relationship between the open-loop and closed-loop data spaces that the closed-loop data space is contained in the open-loop data space as one of its subspaces. By using this relationship, we can derive the data-based stabilization condition for a linear time-invariant discrete-time system, which leads to a linear matrix inequality with a rank constraint.

• 한국지능시스템학회논문지
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• 제27권2호
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• pp.179-186
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• 2017

기술예측은 과거부터 현재까지의 기술개발 결과를 수집, 분석하여 특정 기술의 미래 추세 및 상태를 예측하는 것이다. 일반적으로 특허는 현재까지의 기술개발 결과를 가장 잘 가지고 있다. 왜냐하면 특허에 포함된 세부 기술은 일정기간 동안 배타적 권리가 법에 의해 보장되기 때문이다. 따라서 특허 데이터의 분석을 이용한 기술예측의 다양한 연구가 진행되었다. 특허문서의 분석을 위하여 널리 사용되는 특허 키워드 데이터는 주로 기술키워드에 대한 빈도 값으로 이루어진다. 기존의 많은 특허분석에서는 회귀분석, 박스-젠킨스 모형 등 연속형 데이터분석 기법이 적용하였다. 하지만 빈도 데이터는 이산형 데이터이기 때문에 이산형 데이터분석 방법을 사용해야 한다. 본 연구에서는 이와 같은 문제점을 해결하기 위하여 베이지안 포아송 이산모형을 이용한 특허분석 방법을 제안한다. 연구방법의 성능평가를 위하여 지금까지 출원, 등록된 애플의 전체특허를 분석하여 향후 기술을 예측하는 사례분석을 수행한다.

• 한국정보시스템학회지:정보시스템연구
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• 제26권2호
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• pp.105-121
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• 2017

Purpose It is a major goal to improve the product yields during production operations in the manufacturing industry. Therefore, factory is trying to keep the good quality materials and proper production resources, also find the proper condition of facilities and manufacturing environment for yields improvement. Design/methodology/approach We propose the hybrid framework to analyze to dataset extracted from MES. Those data is about the alarm information generated from equipment, both measurement and equipment process value from production and cycle/pitch time measured from production data these covered products during production. We adapt a data warehousing techniques for organizing dataset, a logistic regression for finding out the significant factors, and a association analysis for drawing the rules which affect the product yields. And then we validate the framework by applying the real data generated from the discrete process in secondary cell battery manufacturing. Findings This paper deals with challenges to apply the full potential of modeling and simulation within CPPS(Cyber-Physical Production System) and Smart Factory implementation. The framework is being applied in one of the most advanced and complex industrial sectors like semiconductor, display, and automotive industry.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.5058-5072
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• 2015

Quaternions have been commonly employed in color image processing, but when the existing pure quaternion representation for color images is used in perceptual hashing, it would degrade the robustness performance since it is sensitive to image manipulations. To improve the robustness in color image perceptual hashing, in this paper a full quaternion representation for color images is proposed by introducing the local image luminance variances. Based on this new representation, a novel Full Quaternion Discrete Cosine Transform (FQDCT)-based hashing is proposed, in which the Quaternion Discrete Cosine Transform (QDCT) is applied to the pseudo-randomly selected regions of the novel full quaternion image to construct two feature matrices. A new hash value in binary is generated from these two matrices. Our experimental results have validated the robustness improvement brought by the proposed full quaternion representation and demonstrated that better performance can be achieved in the proposed FQDCT-based hashing than that in other notable quaternion-based hashing schemes in terms of robustness and discriminability.

• Journal of Preventive Medicine and Public Health
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• 제56권1호
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• pp.59-66
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• 2023

Objectives: The aim of this study was to evaluate the effect of body weight status and sleep duration on the discrete-time hazard of menarche in Korean schoolgirls using multiple-point prospective panel data. Methods: The study included 914 girls in the 2010 Korean Children and Youth Panel Study who were in the elementary first-grader panel from 2010 until 2016. We used a Gompertz regression model to estimate the effects of weight status based on age-specific and sex-specific body mass index (BMI) percentile and sleep duration on an early schoolchild's conditional probability of menarche during a given time interval using general health condition and annual household income as covariates. Results: Gompertz regression of time to menarche data collected from the Korean Children and Youth Panel Study 2010 suggested that being overweight or sleeping less than the recommended duration was related to an increased hazard of menarche compared to being average weight and sleeping 9 hours to 11 hours, by 1.63 times and 1.38 times, respectively, while other covariates were fixed. In contrast, being underweight was associated with a 66% lower discrete-time hazard of menarche. Conclusions: Weight status based on BMI percentiles and sleep duration in the early school years affect the hazard of menarche.

• 한국지반공학회논문집
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• 제23권8호
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• pp.59-68
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• 2007

사질토의 직교 이방 탄성계수를 실험적 방법과 개별 요소법을 이용하여 측정하고 결과를 정량적으로 비교-분석하였다. 실내 시험에서는 미소 응력 제어 반복재하시험과 벤더 엘리먼트의 측정 결과를 조합하여 탄성 특성을 구하였으며, 개별 요소법에서는 실내 시험 방법과 상응하는 반복재하시험을 모사하였다. 축 방향 및 전단방향에 관련된 탄성 특성의 비교 결과는 제한된 조건에서도 개별 요소법이 복잡한 실내 시험 과정을 모사할 수 있음을 보여주었다. 방사 방향 재하시험 결과에서 나타난 두 방법 간 차이의 비교 분석 결과는 개별 요소법이 실내 시험으로 구한 개별 측정치의 정량적 타당성을 확인하는데 충분히 활용될 수 있음을 보여준다.

• Journal of the Korean Data and Information Science Society
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• 제17권2호
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• pp.387-394
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• 2006

In Korea, a proton linear accelerator complex is being built as a part of the 21st Century Frontier Projects. Contingent valuation method (CVM) is a main evaluation method of nonmarket goods for which markets either do not exist at all or do exist only incompletely. This study shows the method can be applied to the benefit assessment of the proton accelerator complex. Using the discrete choice CVM method, this study estimates the willingness-to-pay (WTP) of a would-be user for the proton accelerator complex as 20,133 won per month.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 2006년도 제28회 동계학술발표회 논문집
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• pp.264-297
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• 2006

In this paper, we attempt to analyze consumer preference for the alternative-fuel vehicles based on data from a stated preference using the conjoint analysis. Five possible fuel types (gasoline, diesel, CNG, LPG, Hybrid (electricity+gasoline)) are covered in conjoint cards. To estimate and analyze consumer preference, discrete choice model is used. Specifically, Bayesian mixed logit model is used. Based on estimating results, we discuss the business strategy and policy for the alternative fuel vehicle.

• Journal of the Korean Data and Information Science Society
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• 제23권6호
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• pp.1223-1229
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• 2012

In this paper, we propose a generalized Kullback-Leibler (KL) information for measuring the distance between two distribution functions where the extension to the censored case is immediate. The generalized KL information has the nonnegativity and characterization properties, and its censored version has the additional property of monotonic increase. We also extend the discussion to the discrete case and propose a generalized censored measure which is comparable to Pearson's chi-square statistic.