• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.11-20
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• 2020

As the manufacturing environment becomes more complex, traditional simulation models alone are having a lot of difficulties in reflecting real-time manufacturing situations. Although the Digital Twin concept is actively discussed as an alternative to overcome theses issues, many studies are being carried out only in the product design phase. This research presents a Digital Twin-based manufacturing environment framework for applying the Digital Twin concept to the manufacturing process. Twin model that is operated in virtual space, physical system and databases describing the actual manufacturing environment, are proposed as detailed components that make up the framework. To check the applicability of proposed framework, a simple Digital Twin-based manufacturing system was simulated in a conveyor system using Arena software and Excel VBA. Experiment results have shown that the twin model is transmitted real time data from the physical system via DB and were operating in the same time unit. The Excel VBA fitted parameters defined by cycle time based on historical data that real-time and training data are being accumulated together. This study proposes operating method of digital twin model through the simple experiment examples. The results lead to the applicability of Digital twin model.

• Korean Journal of Remote Sensing
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• v.29 no.3
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• pp.307-314
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• 2013

The Bidirectional Reflectance Distribution (BRD) effect is critical to interpret the surface information using remotely sensed data. This effect was caused by geometric relationship between sensor, target and solar that is inevitable effect for data of optical sensor. To remove the BRD effect, semi-empirical BRDF models are widely used. It is faster to calculate than physical models and demanded less observation than empirical models. In this study, Ross-Li kernel and Roujean kernel were used respectively in National Aeronautics and Space Administration (NASA) and European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) that are used to compare each other. The semi-empirical model consists of three parts which are isotropic, geometric and volumetric scattering. Each part contained physical kernel and empirical coefficients that were calculated by statistical method. Red and NIR channel of SPOT/VEGETATION product were used to compute Nadir BRDF Adjusted Reflectance (NBAR) over East Asia area from January 2009 to December 2009. S1 product was provided by VITO that was conducted atmospheric correction using Simplified Method of Atmospheric Correction (SMAC). NBAR was calculated using corrected reflectance of red and NIR. Previous study has revealed that Roujean geometric kernel had unphysical values in large zenith angles. We extracted empirical coefficients in three parts and normalized reflectance to compare both BRDF models. Two points located forest in Korea peninsular and bare land in Gobi desert were selected for comparison. As results of time series analysis, both models showed similar reflectance change pattern and reasonable values. Whereas in case of empirical coefficients comparison, different changes pattern of values were showed in isotropic coefficients.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.6
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• pp.735-746
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• 1999

We design the robust and inherently fault tolerant decetralized$$H^infty$$ filter for the multisensor state estimation problem when there are insufficient priori informations on the statistical properties of external disturbances. For developing the proposed algorithm, an alternative form of suboptimal$$H^infty$$ filter equations are formulated by applying an alternative form of Kalman filter equations to the indefinite inner product space state model of suboptimal$$H^infty$$ filtering problems. The decentralized$$H^infty$$ filter that consists of local and central fusion filters can be designed effciently using the proposed alternative$$H^infty$$ filiter gain equations. The proposed decentralized$$H^infty$$ filter is robust against un-known external disturbances since it bounds the maximum energy gain from the external disturbances to the estimation errors under the prescribed level$$r^2$$ in both local and central fusion filters and is also fault tolerant due to its inherent redundancy. In addition, the central fusion equations between the global and local data can reduce the unnecessary calculation burden effectively. Computer simulations are made to ceritfy the robustness and fault tolerance of the proposed algorithm.

• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.162-170
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• 2008

The promotion of new product is one of most important object for exhibition design. The majority of conventional exhibition technique has been implemented through one-way communication. However, using digital technology, development of new exhibition techniques is necessary for promotion of high-tech products and consideration of the phases of the times. This paper propose the various possibilities of exhibition design model which is using camera sensing and video input/output. Interactivity is efficient method to communicate between viewers and displays. Viewers can be participate actively and exhibition goal will be accomplish through this. Using camera as visual senses, video input/output technique is offered not only introducing new product but also entertaining viewers through various ways of representation. Physical experience and learning process can be expected from the exhibition space and the object. The classification of the artist who are using video input/output technique and exhibition examples are described. The collaboration on a work with the new media artist and the exhibition design will be complement each other. It will be solved the problems of realization and corporation of idea and technology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4950-4960
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• 2014

This study examined the factors affecting submarine crews' turnover intention. This study reviewed previous research-related turnover in military organizations. The measurement was designed based on the Kano model, which was originally used to survey the customers' satisfaction with a service or a product. The authors conducted a questionnaire survey of 408 submarine crew, from 1, Nov to 30, Nov, 2013. The results showed that the factors that impact the submarine crews' turnover were the sense of insecurity due to the a poor working environment of the submarine, physical risks due to the water pressure, anxiety due to the closed space, and insecure rank-limited promotion system. The paper discusses the implications of the results from the perspective of military social welfare and provides recommendations for setting up the policy for submarine crews' welfare based on the study result.

• The Research Journal of the Costume Culture
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• v.25 no.3
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• pp.270-284
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• 2017

This study aimed to create 3D-printed insoles for flat-footed senior men using 3D systems. 3D systems are product-manufacturing systems that use 3-dimensional technologies like 3D scanning, 3D modeling, and 3D printing. This study used a 3D scanner (NexScan2), 3D CAD programs including Rapidform, AutoCAD, SolidWorks, Nauta+ compiling program, and a 3D printer. In order to create insoles for flat-footed senior men, we analyzed horizontal sections of 3D foot scans We selected 20 flat-footed and 20 normal-footed subjects. To make the 3D insole models, we sliced nine lines on the surface of the subjects' 3D foot scans, and plotted 144 points on the lines. We calculated the average of these 3D coordinates, then located this average within the 3D space of the AutoCAD program and created 3D sole models using the loft surface tools of the SolidWorks program. The sole models for flat feet differed from those of normal feet in the depth of the arch at the inner sideline and the big toe line. We placed the normal-footed sole model on a flat-footed sole model, and the combination of the two models resulted in the 3D insole for flat feet. We printed the 3D modeled insole using a 3D printer. The 3D printing material was an acrylic resin similar to rubber. This made the insole model flexible and wearable. This study utilized 3D systems to create 3D insoles for flat-footed seniors and this process can be applied to manufacture other items in the fashion industry as well.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.3
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• pp.141-147
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• 2018

In a time when product development cycles are getting shorter and shorter, many companies are making efforts to develop products with high reliability in a short period of time, accelerated life test is widely used as a method to quickly evaluate reliability. Accelerated life test reduces the test life or the life of the product from the observed data by shortening the lifetime of the product or abruptly lowering the performance under the worse condition than the actual condition in order to shorten the test cost or the test time. In this paper, BL3640A-06P+RB35, DC12V model, which is used in the support device of an automatic rotation type digital signage, which display various information such as textures and images on a display screen in a public place or a commercial space, BLDC motors were subjected to a constant stress test and at the rotational speed of 1rpm, $180^{\circ}$ rotation and reverse rotation under actual use conditions, the stress was imposed on the rotating speed of 2rpm and the weight of the actual installed product from 22.2kgf to 10kgf were installed. The lifetime of the actual use environment condition is 23,545 hours and the rotation speed is accelerated. The life time of the acceleration condition with the additional weight is 1,380 hours. The acceleration factor is calculated as 17.06, the one year guarantee test day is 235 days to 14 days, of the period from 470 days to 28 days, and the third year from 704 days to 42 days. The test date of the BLDC motor was tested on the shortened test date, and the rotational speed and the current value were measured. It is found that there is no defect even if it operates as the test date corresponding to the specified one year warranty period and the 3 year accelerated life test which is experimented. Using the statistical technique of the regression analysis the expected time for the motor to defect to #4 samples was 20 years.

• Science of Emotion and Sensibility
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• v.17 no.1
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• pp.79-92
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• 2014

This study is aimed at minimizing the errors in using a sensitivity evaluation model that could occur when sensitivity analysis method is actively used for design evaluation. To extract words of a contrantion-type model by product, interior space, and streetscape design, primary word refinement was conducted with the words extracted from preceding studies. The analysis revealed that 19 words were used in all three fields. A reliability analysis revealed that different words had a bad impact on the reliability in each field. The applicability was reviewed through reliability analysis of EPA model as contraction-type and PAD model as inference-type. The results are as follows. Although the reliability of the contrantion-type model was higher than that of inference-type model in all three fields, the differences in Cronbach's Alpha were small. Also, When the reliability was analyzed after deleting the words that had a bad impact on reliability, the differences in the reliability's coefficients were clearly significant. Therefore, it is necessary to select words suitable for sensitivity evaluation target and objectivity of the evaluation can be boosted by using a proper model. Analysis of the sensitivity evaluation model suitable for future environmental evaluation should be analyzed with various statistical methods, beyond verification of reliability.

• Journal of Astronomy and Space Sciences
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• v.32 no.2
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• pp.127-136
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• 2015

We present a by-product of our long term photometric monitoring of cataclysmic variables. 2MASS J18024395 +4003309 = VSX J180243.9 +400331 was discovered in the field of the intermediate polar V1323 Her observed using the Korean 1-m telescope located at Mt. Lemmon, USA. An analysis of the two-color VR CCD observations of this variable covers all the phase intervals for the first time. The light curves show this object can be classified as an Algol-type variable with tidally distorted components, and an asymmetry of the maxima (the O'Connell effect). The periodogram analysis confirms the cycle numbering of Andronov et al. (2012) and for the initial approximation, the ephemeris is used as follows: Min I. BJD = 2456074.4904+0.3348837E. For phenomenological modeling, we used the trigonometric polynomial approximation of statistically optimal degree, and a recent method "NAV" ("New Algol Variable") using local specific shapes for the eclipse. Methodological aspects and estimates of the physical parameters based on analysis of phenomenological parameters are presented. As results of our phenomenological model, we obtained for the inclination $i=90^{\circ}$, $M_1=0.745M_{\odot}$, $M_2=0.854M_{\odot}$, $M=M_1+M_2=1.599M_{\odot}$, the orbital separation $a=1.65{\cdot}10^9m=2.37R_{\odot}$ and relative radii $r_1=R_1/a=0.314$ and $r_2=R_2/a=0.360$. These estimates may be used as preliminary starting values for further modeling using extended physical models based on the Wilson & Devinney (1971) code and it's extensions

• Journal of the East Asian Society of Dietary Life
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• v.22 no.2
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• pp.315-321
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• 2012

In this study, the product attributes that give customers the estimated benefits and products that can predict the customer's choice conjoint analysis techniques to identify the restaurant affinity markets a new dining concept was to develop. Questionnaire for this study of 400 non-response is negative and insincere characters, except for the final analysis, the questionnaire Part 309 was the target. Conjoint model used in this study Pearson's R is 0.928 ($p$<0.000), Kendall's tau is 0.750 ($p$<0.000) with an orthogonal plan was well suited for profiling attributes are extracted 16. Part of the relative importance of the value of the property to determine the result of analyzing the properties that are most important at the level of the respondents of the induct (38.46%), and followed by price (30.52%), Atmosphere (18.28%), and Exclusive space (12.73%) was followed. Portion of the property value for each analysis among industry preference for the Italian food was highest, a nature-friendly interior atmosphere had the highest affinity Average per price at 10,000 won~30,000 won or less than the amount of affinity was higher location of the restaurant alone, showed that space preferred. Through simulation in a virtual seafood restaurant nature-friendly image, average price per person ranging from 10,000 to 30,000won at an exclusive restaurant was most preferred.