• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 한국해양공학회 2004년도 학술대회지
• /
• pp.166-172
• /
• 2004

An underwater motion measurement system was constructed for applications to the model basin. A commercial motion capture system, FALCON of Motion Analysis Corp., which corrects automatically the distortion caused by refraction of the light passing through water and air, was adopted for underwater motion measurement. The modifications of FALCON system were performed: waterproofing camera housings, markers, connectors, and a new blue ring lighter. the accuracy of the motion measurement was obtained within the calibration error of 0.87mm in average and 0.89mm in standard deviation for the distance of 500mm between two markers on the calibration device. the volume of $2100mm(length)\times2100mm(breadth)\times2300mm(Height)$ was covered with 4 cameras of the underwater motion measurement system. For the performance verification, motion measurement test of a vertical mooring chain model excited at the top end was carried out. The 3D motions of mooring model were measured with variable amplitude and period of the forced excitation. Higher order motions of the mooring model were observed as the excitation period decreases. the performance of the system was verified by successfully measuring 3D motion of mooring model.

• Journal of Information Technology Services
• /
• 제7권4호
• /
• pp.247-268
• /
• 2008

This study aims to develop an integration performance measurement model for each stage of information systems integration. In order to achieve the purpose of the research, first of all, the concepts of IS integration or consolidation are analyzed through theoretical and practical reviews. Also, a number of important studies of domestic and overseas cases about the stage models of IS integration or consolidation are critically reviewed. Second, we proposed three step stage model of is integration, Physical Integration stage, Application Integration stage, Service Integration stage, and Also proposed the performance measurement model for each stage of information systems integration. Third, especially in case of performance indicators and performance measurement methodology for physical integration stage are illustratively proposed, based upon the case of NCIA (National Computing Integration Agency) in Korea. This study provides the theoretical basis for reasonably deriving the stage model and performance measurement model for each stage of Information Systems Integration, and they are validating through investigating domestic and foreign practices. The results of this study are very likely to contribute to presenting the practical guideline for desirably implementing is integration or IS consolidation.

• Journal of the Korea Safety Management & Science
• /
• 제5권4호
• /
• pp.229-243
• /
• 2003

This paper suggests the process of performance measurement system development for B2B e-Marketplace using BSC (Balanced Scorecard). As the first step, main features and factors affecting performance of e-Business company and especially of B2B e-Marketplaces were derived based on the literatures. For the 2nd step, the nonnative performance measurement model for B2B e-Marketplace was suggested. Especially, the research range that the model covers is restricted to the neutral and systematic sourcing B2B e-Marketplace. And, the performance measurement model was based on BSC, for the BSC is very powerful and sound tool among all the available performance measurement systems. Also, the model was based on the AHP (Analytic Hierarchy Process) to make the model more structured, and to draw weights of performance measures from experts

• International Journal of Computer Science & Network Security
• /
• 제21권12호
• /
• pp.157-164
• /
• 2021

The aim of this study is to provide empirical evaluation of the accuracy of data-model fit using growing levels of invariance models. Overall model accuracy of factor solutions was evaluated by the examination of the order for testing three levels of measurement invariance (MIV) starting with configural invariance (model 0). Model testing was evaluated by the Chi-square difference test (∆𝛘²) between two groups, and root mean square error of approximation (RMSEA), comparative fit index (CFI), and Tucker-Lewis index (TLI) were used to evaluate the all-model fits. Factorial invariance result revealed that stability of the models was varying over increasing levels of measurement as a function of variable-to-factor ratio (VTF), subject-to-variable ratio (STV), and their interactions. There were invariant factor loadings and invariant intercepts among the groups indicating that measurement invariance was achieved. For VTF ratio (3:1, 6:1, and 9:1), the models started to show accuracy over levels of measurement when STV ratio was 6:1. Yet, the frequency of stability models over 1000 replications increased (from 69% to 89%) as STV ratio increased. The models showed more accuracy at or above 39:1 STV.

• Transactions of the Korean hydrogen and new energy society
• /
• 제33권6호
• /
• pp.692-698
• /
• 2022

With the expansion of domestic hydrogen fuelling station infrastructure, it is necessary to secure reliability among hydrogen traders, and for this, technology to accurately measure hydrogen is important. In this study, 4 types of hydrogen trading volume calculation models (model 1-4) were presented to improve the accuracy of the hydrogen trading volume. In order to obtain the reference value of model 4, and experiment was conducted using a flow rate measurement equipment, and the error rate of the calculated value for each model was compared and analyzed. As a result, model 1 had the lowest metering accuracy, model 2 had the second highest metering accuracy and model 3 had the highest metering accuracy until a certain point. But after the point, model 2 had the highest metering accuracy and model 3 had the second metering accuracy.

• Structural Engineering and Mechanics
• /
• 제44권5호
• /
• pp.585-600
• /
• 2012

This paper presents a Modified Tikhonov Regularization (MTR) method in model updating for damage identification with model errors and measurement noise influences consideration. The identification equation based on sensitivity approach from the dynamic responses is ill-conditioned and is usually solved with regularization method. When the structural system contains model errors and measurement noise, the identified results from Tikhonov Regularization (TR) method often diverge after several iterations. In the MTR method, new side conditions with limits on the identification of physical parameters allow for the presence of model errors and ensure the physical meanings of the identified parameters. Chebyshev polynomial is applied to approximate the acceleration response for moderation of measurement noise. The identified physical parameter can converge to a relative correct direction. A three-dimensional unsymmetrical frame structure with different scenarios is studied to illustrate the proposed method. Results revealed show that the proposed method has superior performance than TR Method when there are both model errors and measurement noise in the structure system.

• Journal of the Korean Data and Information Science Society
• /
• 제27권6호
• /
• pp.1645-1651
• /
• 2016

A lot of data, particularly in the medical field, contain variables that have a measurement error such as blood pressure and body mass index. On the other hand, recently smoothing methods are often used to solve a complex scientific problem. In this paper, we study a Bayesian curve-fitting under functional measurement error model. Especially, we extend our previous model by incorporating covariates free of measurement error. In this paper, we consider penalized splines for non-linear pattern. We employ a hierarchical Bayesian framework based on Markov Chain Monte Carlo methodology for fitting the model and estimating parameters. For application we use the data from the fifth wave (2012) of the Korea National Health and Nutrition Examination Survey data, a national population-based data. To examine the convergence of MCMC sampling, potential scale reduction factors are used and we also confirm a model selection criteria to check the performance.

• Journal of KSNVE
• /
• 제10권2호
• /
• pp.269-279
• /
• 2000

This paper deals with the development of biomechanical model on a seat with backrest support in the vertical direction. Four kinds of biomechanical models are discussed to depict human motion. One DOF model mainly describes z-axis motion of hip, two and three DOF models describe z-axis of hip and head, and while nine DOF model suggested in this study represents more motion than the otehr model. Three kinds of experiments were executed to validate these models. The first one was to measure the acceleration of the floor and hip surface in z-axis, the back surface in x-axis, and the head in z-axis under exciter. From this measurement, the transmissiblities of each subject were obtained. The second one was the measurement of the joint position by the device having pointer and the measurement of contact position between the human body and the seat by body pressure distribution. The third one was the measurement of the seat and back cushion by dummy. The biomechanical model parameters were obtained by matching the simulated to the experimental transmissiblities at the hip, back, and head.

• Journal of the Korean Society of Clothing and Textiles
• /
• 제33권1호
• /
• pp.55-67
• /
• 2009

The purpose of this study is to develop well-being lifestyle measurement. Data were collected from a total of 251 Korean females ranging from 20 to 50 years old. The measurement items were developed by focus group interview to well-being consumers. Through a series of exploratory factor analysis and confirmatory factor analysis, the 7 sub-factors and 14 items that construct final measurement model of well-being lifestyle were identified: Health oriented eating habits, social welfare oriented consumption, interest in health policy, self-esteem enhancement, sports activity, volunteer for local community, use of cosmetics made of natural components. Fitness of measurement model and reliability and discriminant validity of measurement variables were accepted as a good level.

• Journal of Electrical Engineering and Technology
• /
• 제4권2호
• /
• pp.149-158
• /
• 2009

It is important to derive reliable parameter values in the measurement-based load model development of electric power systems. However parameter estimation tasks, in practice, often face the parameter identifiability issue; whether or not the model parameters can be estimated with a given input-output data set in reliable manner. This paper introduces concepts and practical definitions of the local identifiability of model parameters. A posteriori local identifiability is defined in the sense of nonlinear least squares. As numerical examples, local identifiability of third-order induction motor (IM) model and a Z-induction motor (Z-IM) model is studied. It is shown that parameter ill-conditioning can significantly affect on reliable parameter estimation task. Numerical studies show that local identifiability can be quite sensitive to input data and a given local solution. Finally, several countermeasures are proposed to overcome ill-conditioning problem in measurement-based load modeling.