• Journal of Mechanical Science and Technology
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• v.19 no.4
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• pp.976-984
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• 2005

This paper presents the analysis results of dynamics in the billiards game within the frame­work of rigid-body mechanics and a numerical simulation program. The friction exists between the ball and the table bed as well as between the ball and the rail. There are three parts in the dynamic behavior of the ball on the table bed; motion of the ball on the table bed, collision between balls, and collision between the ball and the cushion. During the development of the simulation program, the dynamics problems such as rolling motion and three-dimensional frictional impact motion have been analyzed in detail. The theoretical issues are implemented into a viable graphic simulation program and its efficacy is demonstrated through the experi­mental validation of the billiards game. The resulting analysis results are verified quantitatively and qualitatively using high-speed video camera. Through the experimental tests, it was found that the physical parameters such as coefficients of restitution and friction vary according to the motion variables and corresponding empirical formulations were developed. The simulation and experimental results agree well.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.7
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• pp.29-38
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• 1997

A closed-loop system modeling of an active/semiactive suspension system has been accomplished through an artificial neural network. A 7DOF full model as a system's equation of motion has been derived and an output feedback linear quadratic regulator has been designed for control purpose. A training set of a sample data has been obtained through a computer simulation. A 7DOF full model with LQR controller simulated under several road conditions such as sinusoidal bumps and rectangular bumps. A general multilayer perceptron neural network is used for dynamic modeling and target outputs are fedback to the a layer. A backpropagation method is used as a training algorithm. Model validation of new dataset have been shown through computer simulations.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.2
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• pp.113-125
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• 2012

The logistic model and the Bass model have diverse names and formulae in diffusion theory. This diversity makes users or readers confused while it also contributes to the flexibility of modeling. The method of handling the integration constant, which is generated in process of deriving the closed form solution of the differential equation for a diffusion model, results in two different 'actual' models. We rename the actual four models and propose the usage of the models with respect to the purpose of model applications. The application purpose would be the explanation of historical diffusion pattern or the forecasting of future demand. Empirical validation with 86 historical diffusion data shows that misuse of the models can draw improper conclusions for the explanation of historical diffusion pattern.

• Journal of KIISE:Software and Applications
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• v.27 no.12
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• pp.1141-1154
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• 2000

본 논문에서는 Java 프로그램의 복잡도를 측정하기 위해 필요한 인자들을 제안하였다. 이러한 인자들을 추출하기 위해 Java 프로그램을 분석하여 객체지향 설계 척도 값들을 계산하고 통계적 분석을 수행하였다. 그 결과 기존의 연구에서 발견되었던 클래스의 크기 인자 외에도 메소드 호출 빈도, 응집도, 자식 클래스의 수, 내부 클래스 및 상속 계층의 깊이가 주요 인자임이 파악되었다. 클래스의 크기 척도로 분류되었던 자식 클래스의 수는 다른 크기 척도들과 다른 성질을 가진다는 것을 발견하였다. 또한 프로그램의 크기가 커지고 결합도가 높아질수록 응집도가 떨어진다는 것을 입증하였다. 그리고 인자 분석을 바탕으로 인간의 인지 능력과 인자의 상관관계를 고려한 가중치를 적용하기 위해 인자별로 회귀분석을 수행하였다. 보다 적은 척도를 가지고 인자를 설명할 수 있는 회귀식을 도출하였다. 두 그룹에 대한 교차 검증 결과 회귀식이 높은 신뢰도를 가지는 것으로 나타났다. 따라서 본 논문에서 제안한 인자들을 이용하는 경우 Java 프로그램의 복잡도를 측정할 수 있는 새로운 척도로 사용할 수 있다.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.4
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• pp.149-165
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• 2002

This study establishes key factors on ISM (Internet Shopping Mall) performance in Korea. The four factors are derived from the relevant literature and clarified the concept of ISM characteristics, customer characteristics, ISM evaluation level. and perceived risks by distinguishing between its components and determinants. ISM performance indicators were derived from the previous studios classifying by ISM attitude and ISM usage. We examine on the impact of ISM characteristics and customer characteristics on the ISM evaluation level, then its level and perceived risks on the ISM performance. Hypotheses on four factors of ISM performance were tested for 172 respondents. Results indicate that four factors may partially serve as key predictors on ISM performance. ISM characteristics and customer characteristics was found to be positively influenced on ISM evaluation level, and its level also positively affected on ISM performance while perceived risks negatively affected on ISM performance.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.2
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• pp.123-152
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• 2002

This study establishes key success Predictors of internet venture enterprises in Korea. The five factors are derived from the relevant literature and clarified the concept of entrepreneurship, industrial level, enterprise strategy, organizational capability, and resource procurement by distinguishing between its components and determinants. Organizational performance indicators were derived from the previous studies classifying by financial performance indicator and non-financial performance indicator using by recent evaluation method as BSC (Balanced Scorecard). We then examine the impact of critical success factors on the internet venture performance. Hypotheses on five factors of internet venture were tested for 103 organizations. Results indicate that critical success factors may serve as key predictors. Organizational strategy and resource capability was found to be positively influenced on both financial performance indicator and non-financial performance indicator while entrepreneurship, industrial level and organizational capability positively affected only non-financial performance indicator.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.3
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• pp.135-149
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• 2007

This paper investigates the relative effect of each ISO 9001 : 2000 quality management system's requirement and business performance. The empirical tests are conducted in ISO 9001 certification companies. As a result, the $1^{st}$, it shows the requirements positively affect performance of financial. The $2^{nd}$, also it shows the requirements positively affect non-financial performance. The $3^{rd}$ also it show the non-financial performance positively effect performance of financial performance.

• Journal of the Korean Solar Energy Society
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• v.25 no.2
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• pp.9-17
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• 2005

Images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. For the validation, estimated solar radiation fluxes are compared with observed solar radiation fluxes at 16 sites over the Korean peninsular from January 1982 to December 2004. Estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -7.8 to +7.0% from the measured values and the yearly averaged horizontal global insolation of Korean peninsula was turned out to be $3.56kW/m^{2}/day$.

• Nuclear Engineering and Technology
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• v.44 no.6
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• pp.663-672
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• 2012

As software based digital I&C (Instrumentation and Control) systems are used more prevalently in nuclear plants, enhancement of software dependability has become an important issue in the area of nuclear I&C systems. Critical attributes of software dependability are safety and reliability. These attributes are tightly related to software failures caused by faults. Software testing and V&V (Verification and Validation) activities are hence important for enhancing software dependability. If the risky modules of safety-critical software can be predicted, it will be possible to focus on testing and V&V activities more efficiently and effectively. It should also make it possible to better allocate resources for regulation activities. We propose a prediction technique to estimate risky software modules by adopting machine learning models based on software complexity metrics. An empirical study with various machine learning algorithms was executed for comparing the prediction performance. Experimental results show SVMs (Support Vector Machines) perform as well or better than the other methods.

• The Journal of Fisheries Business Administration
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• v.44 no.2
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• pp.51-68
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• 2013

The objective of this study is to analyze how consumption value affects customer satisfaction toward eco-friendly seafood products. Moderating role of gender is also examined. For empirical validation of our model, data were collected from a cross-sectional survey of 307 consumers in the South Korea, who have bought a eco-friendly seafood, a representatives eco-friendly product. The results demonstrated several important findings. First, emotional consumption value, social consumption value and functional consumption value had significant positive effects on eco-friendly seafood product satisfaction, Second, interaction effect of social value and gender had a positive effect on satisfaction. Third, interaction effect of functional value and gender had a negative effect on satisfaction. Theoretical and managerial implications are suggested.