• KIEAE Journal
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• v.6 no.4
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• pp.25-32
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• 2006

Mock-up model can be applied to measure accurate performance data but difficult to apply the variables in experiment. There can be a slight experiment errors in Scale model, but various parameters can be applied for a objective experiment. This paper aims to compare the daylighting performance in 1, 1/5, 1/10 scale model of offices and analyze the experiment errors to certificate the influence of model experiment. To analyse daylighting performance, a comparison of a Mock-up model, sized $12.0m(w){\times}7.2m(l){\times}3.7m(h)$, designed for experimentation of daylighting systems and its 1:5, 1:10 scale model. It has an identical configuration of reference room and the test room. For the test room, the lightshelf system was designed as Micro-4 reflective material. To assess work plane illuminance and light factor, photometric sensors of each room were installed at work-plane(6 points) and exterior horizontal illuminance (1 point). And luminance of window, rare of the room was measured under clear sky. It is to be monitored by Agilent data logger, photometric sensor Li-cor and the Radiant Imaging ProMetric 1400. Comparisons with a light factor, increase-decrease ratio and luminance are discussed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.703-713
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• 2011

In this study, to minimize trial and error in the design and manufacturing processes of a high-precision large-surface micro-grooving machine which is able to fabricate the molds for 42 inch LCD light guide panels, the effects of the structural deformation of the micro-grooving machine according to the positions of the X-axis, Y-axis and Z-axis feed systems were examined on the tool tip displacement errors associated with the machining accuracy. The virtual prototype (finite element model) of the micro-grooving machine was constructed to include the joint stiffnesses of the hydrostatic bearings, hydrostatic guideways and linear motors, and then the tool tip displacement errors were measured from the virtual prototype. Especially, to establish the prediction model of the tool tip displacement errors, which was constructed using the positions of the X-axis, Y-axis and Z-axis feed systems as independent variables, the response surface method based on the central composite design was introduced. The reliability of the prediction model was verified by the fact that the tool tip displacement errors obtained from the prediction model coincided well those measured from the virtual prototype. And the causes of the tool tip displacement errors were identified through the analysis of interactions between the positions of the X-axis, Y-axis and Z-axis feed systems.

• Korean System Dynamics Review
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• v.10 no.1
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• pp.33-60
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• 2009

This study explores the limitation in making a causal model through an existing case and proposes an alternative plan to improve a theoretical system of causation modeling. To make a dynamic and actual model, several principles are needed such as reality based analysis of system structures and dynamics, consistent expression of causations, conversion of numerical formulas to causal relations, classification and arrangement of variables by size of concept, etc. However, it is hard to find cases to apply these considerations from existing models in System Dynamics. Therefore, this study verifies errors of derived models from literatures and proposes principles and guides that should be considered to make a sound dynamic model on a causal map. It contributes to making an opportunity for exciting public opinion to improve theory about causal maps, yet it has limitation that the study does not advance forward to the experimental step. For future study, it plans to make up by classifying and leveling causal variables, developing a dynamic BSC model.

• Journal of Construction Engineering and Project Management
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• v.3 no.3
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• pp.35-41
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• 2013

All infrastructure projects are said to be inter-dependent, uncertain and labour-intensive in nature. There is no exception for building services sub sector. For a real time project such as 'The construction, extension and refurbishment of Employees' State Insurance Corporation (ESIC) Hospital at Tirupathy, India with total area of 45,000 square feet at an estimated cost of 1100 million rupees, a generic process model is developed to simulate the effect of set of identified variables on construction project. The 'Stocks and Flows' of dynamic model affords relevant insights to project managers, who apply this knowledge when designing better performance through more appropriate project planning. It is concluded from the model-based approach that building services works can be improved through specific better focussed managerial efforts, such as an increasing coordination effectiveness at the planning stage, clarifying prerequisite conditions prior to installations. Otherwise, pending works arising from work clashes can lead to knock-on effects resulting in productivity constraints and pressures, as well as more rework and demolition. Current study reveals that the model enables deep insight into various interdependent processes, their by improving construction performance levels, by addressing the dynamics of design errors and defective works, and recovering delayed schedule.

• Nuclear Engineering and Technology
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• v.44 no.4
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• pp.355-362
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• 2012

The aim of this study was to develop a bundle position-wise linear model (BPLM) to predict Pressure Tube (PT) diametral creep employing the previously measured PT diameters and operating conditions. There are twelve bundles in a fuel channel, and for each bundle a linear model was developed by using the dependent variables, such as the fast neutron fluences and the bundle coolant temperatures. The training data set was selected using the subtractive clustering method. The data of 39 channels that consist of 80 percent of a total of 49 measured channels from Units 2, 3, and 4 of the Wolsung nuclear plant in Korea were used to develop the BPLM. The data from the remaining 10 channels were used to test the developed BPLM. The BPLM was optimized by the maximum likelihood estimation method. The developed BPLM to predict PT diametral creep was verified using the operating data gathered from Units 2, 3, and 4. Two error components for the BPLM, which are the epistemic error and the aleatory error, were generated. The diametral creep prediction and two error components will be used for the generation of the regional overpower trip setpoint at the corresponding effective full power days. The root mean square (RMS) errors were also generated and compared to those from the current prediction method. The RMS errors were found to be less than the previous errors.

• International Journal of Reliability and Applications
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• v.6 no.1
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• pp.41-51
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• 2005

The Bayes estimators of the parameters included in the complementary Weibull reliability model are obtained. In the process of deriving Bayes estimators, the scale and shape parameters of the complementary Weibull distribution are considered to be independent random variables having prior exponential distributions. The maximum likelihood estimators of the desired parameters are derived. Further, the least square estimators are obtained in closed forms. Simulation study is made using Monte Carlo method to make a comparison among the obtained estimators. The comparison is made by computing the root mean squared errors associated to each point estimation. Based on the numerical study, the Bayes procedure seems better than the maximum likelihood and least square procedures in the sense of having smaller root mean squared errors.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.126-139
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• 2011

In the traditional four-step travel demand models, each step is sequentially conducted following the model estimation at the previous step. The accuracy of the following model is partly dependent on whether the model at the former stage was properly established or not. Therefore, trip generation, which is the first step in this conventional model, has great effects on the modeling process and forecasting results. Linear regression models for trip generation of Seoul Metropolitan Area might increase the forcasting errors, since a variety of land-use characteristics are not considered. Hence, in this study, zonal factors such as socioeconomic and land use variables are included to improve the elaboration of trip generation. Comparing the %RMSE with the existing models, which contain bigger errors in the zones highly based on the secondary and tertiary industries than residence-based, the trip generation models including those variables seem more appropriate overall.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.119-128
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• 2010

Mode choice behavior is associated with travelers' latent behavior that is an unobservable preference to travel behavior or mode characteristics. This paper specifically addresses the problem of unobservable factors, that is latent behavior, in mode choice models. Consideration of latent behavior in mode choice models reduces the errors that come from unobservable factors. In this study, the authors defined the latent variables that mean a quantitative latent behavior factors, and developed the combined RP/SP model with latent variables using the mode choice behavior survey data. The data has traveler's revealed preference of existent modes along the Han River and stated preference of new water transit on the Han River. Also, The data has travelers' latent behavior. Latent variables were defined by factor analysis using the latent behaviour data. In conclusion, it is significant that the relationship between traveler's latent behavior and mode choice behavior. In addition, the goodness-of-fit of the mode choice models with latent variables are better than the model without latent variables.

• Journal of Korean Society for Quality Management
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• v.21 no.1
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• pp.152-160
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• 1993

In developing a quadratic regression relationship, independent variable is frequently measured with error. In this paper the integrated mean square error of prediction is developed for a quadratic functional relationship model as a measure of the effect of measurement error of the independent variable on the predicted values. The amount of the effect of error is presented and illustrated with an example.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.176-181
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• 2024

The desktop-level 3D printing machines makes it easier for independent designers to produce collectible models. Desktop 3D printers that use FDM (Fused Deposition Modeling) technology usually use a minimum nozzle diameter of 0.4mm. When using FDM printers to make Gunpla models, Thin slice structures are prone to slicing errors, which lead to deformation of printed objects and reduction in structural strength. This paper aims to analyze the printing model that produces errors, control a single variable among the three variables of slice layer height, slice wall thickness and filament type for comparative testing, and find a way to avoid gaps. To provide assistance for using FDM printers to build models containing thin-walled structures.