• Spatial Information Research
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• v.14 no.1 s.36
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• pp.29-41
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• 2006

Geostatistical data are obtained only at selected sites even though they are potentially available at any location In a continuous surface. Therefore it is necessary to estimate the unknown values at unsampled locations based on observations. In this study we compared the accuracy of 5 spatial interpolation methods: local trend surface, IDW, RBF, ordinary kriging, universal kriging. These interpolation methods were applied to annual rainfall data. As the results of validation tests, universal kriging with gaussian variogram model showed the best accuracy in comparison with other interpolation methods. In the case of kriging, the predicted values were more accurate and within a more narrow range than other methods. In contrast with kriging, local trend surface analysis, IDW and RBF showed the wide range of predicted values and abrupt changes between neighbors.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.3
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• pp.70-77
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• 2014

In this paper, the development of unique model of the 2.75 inch rocket propulsion system is described. Recently developed korean 2.75 inch rocket propulsion system shows the improvement of a flame stability resulted from a change in the configuration of propellant grain, and of an incidental ignition protection function using the EMI(electromagnetic interference) filter on ignition system. Moreover it is shown that a directional flight stability is improved by increasing the number of fins and changing the nozzle configuration. Static firing test and thermal shock test were conducted for the validation before flight, and flight test of 210 rounds of rockets was conducted to verify the trajectory uniformity. In addition, intellectual property issues can be overcome with the unique korean 2.75 inch rocket motor as well as the performance improvement.

• Safety and Health at Work
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• v.5 no.2
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• pp.80-85
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• 2014

Background: Currently available questionnaires for evaluating the quality of worklife do not fully examine every factor related to worklife in all cultures. A tool in Thai is therefore needed for the direct evaluation of the quality of worklife. Our aim was to translate the Work-related Quality of Life Scale-2 (WRQLS-2) into Thai, to assess the validity and reliability of the Thai-translated version, and to examine the tool's accuracy vis-$\grave{a}$-vis nursing in Thailand. Methods: This was a descriptive correlation study. Forward and backward translations were performed to develop a Thai version of the WRQLS. Six nursing experts participated in assessing content validity and 374 registered nurses (RNs) participated in its testing. After a 2-week interval, 67 RNs were retested. Structural validity was examined using principal components analysis. The Cronbach's alpha values were calculated. The respective independent sample t test and intraclass correlation coefficient were used to analyze known-group validity and test-retest reliability. Multistate sampling was used to select 374 RNs from the In- and Outpatient Department of Srinagarind Hospital of the Khon Kaen University (Khon Kaen, Thailand). Results: The content validity index of the scale was 0.97. Principal components analysis resulted in a seven-factor model, which explains 59% of the total variance. The overall Cronbach's alpha value was 0.925, whereas the subscales ranged between 0.67 and 0.82. In the assessment results, the known-group validity was established for the difference between civil servants and university employees [F (7.982, 0.005) and t (3.351; p < 0.05)]. Civil servants apparently had a better quality worklife, compared to university employees. Good test-retest reliability was observed (r = 0.892, p < 0.05). Conclusion: The Thai version of a WRQLS appears to be well validated and practicable for determining the quality of the work-life among nurses in Thailand.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.4
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• pp.182-190
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• 2020

This study reports a series of drop impact tests performed to generate denting damages on stiffened plates and their residual ultimate strength tests under axial compression. The models were fabricated of general structural steel, and each model has six longitudinal stiffeners and two transverse frames. Among six fabricated models, four were damaged, and two were left intact for reference. To investigate the effects of collision velocity and impact location on the extent of damage, the drop height and the impact location were changed in each impact test. After performing the collision tests, the ultimate axial compression tests were conducted to investigate the residual strengths of the damaged stiffened plates. Finite element analyses were also carried out using a commercial package Abaqus/Explicit. The material properties obtained from a quasi-static tensile tests were used, and the strain-rate sensitivity was considered. After importing the collision simulation results, the ultimate strength calculations were carried out and their results were compared with the test data for the validation of the finite element analysis method.

• Journal of Biomedical Engineering Research
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• v.35 no.4
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• pp.81-86
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• 2014

One of the methods for Parkinson's disease(PD) tremor evaluation is the Clinical Tremor Rating Scale(CTRS). However, the method has some limitations that clinician ratings can vary because the scores are subjectively rated. In addition, most researches usually collected data measured on the more affected arm. In this study, we developed a portable wearable system(SNUMAP system) for measuring PD tremor. The SNUMAP system captures 3-dimensional motion using tri-accelerometer and tri-gyroscope on finger and wrist. 40 PD patients participated in resting tremor and postural tremor tasks, while wearing the system on both hands simultaneously. Estimated tremor scores from Leave-One-Out Cross Validation for regression were highly correlated to the average clinician CTRS scores for rest tremor($r^2$ = 0.87, RMSE = 0.48) and postural tremor($r^2$ = 0.82, RMSE = 0.48). Therefore, the quantitative assessment model can improve treatment of PD patients.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.507-517
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• 2016

This study examines the types and characteristics of traumatic events middle-aged women experience and to explore the effects of attachment in the process of post-traumatic growth and forming a self-realization. 221 of participants were middle-aged women from the area of Seoul, Gyeong-Gi and the survey was composed of post-traumatic experience questionnaire, attachment scale, post-traumatic growth scale, self-realization scale. The type and characteristics of traumatic experience by middle-aged women were executed by frequency analysis and correlation with the structural equation model validation was used in order to analyze the relationship between each variable. the major findings are First, the loss of someone close(such as death, breaking up, divorce, breaking off) was reported as something general yet the biggest crisis event, Second, looking at the relationship between attachment, post-traumatic growth and self-realization, the secure parental attachment and spiritual transformation showed the correlation in all subregions except the subvariables of humanity and self-acceptance and Third, the results of Structural Equation Modeling shows that attachment has a static effect on post-traumatic growth and self-realization, and post-traumatic growth appeared to be the mediating factor of attachment and self-realization.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.5
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• pp.512-517
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• 2014

This paper describes the development of new sweeping machine based on Cyclone Technology, which maintains constant suction power and uses it in a industrial applications as a method for dust removed from grinding work. The performance of a cyclone separator is determined by the turbulence characteristics and particle-particle interaction. To achieve this goal, we design cyclone technology based dust separator for sweeping machine has been proposed as a system which is suitable to work utilizing dust suction alternative to conventional manual system. and Numerical analysis with computational fluid dynamics(CFD) was carried out to investigate the working fluid that flow into cyclone dust separator in order to design optimal structure of the sweeping machine. The validation of cyclone model with CFD is carried out by comparing with experimental results.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.481-486
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• 2004

본 연구에서는 분석된 산사태 발생원인을 근거로 산사태 발생 가능 지역에 대한 산사태 발생원인에 대한 등급값을 이용하여, 인접한 연구지역에 교차 적용하여 위험성을 평가하여 취약성도를 작성하고 산사태 피해 예방을 위한 방재 사업, 국토개발 계획 및 건설계획을 위한 기초 자료로 적용 및 활용할 수 있도록 하였다. 연구대상 지역은 여름철 집중호우시 산사태가 많이 발생하는 지역으로 정하였으며, 행정구상으로 강원도 강릉시 사천면 사기막리와 주문진읍 삼교리에 해당한다. 산사태가 발생할 수 있는 요인으로 지형도로부터 경사, 경사방향, 곡률, 수계추출을, 정밀토양도로부터 토질, 모재, 배수, 유효토심, 지형을, 임상도로부터 임상, 경급, 영급, 밀도를, 지질도로부터 암상을, Landsat TM 영상으로부터 토지이용도와 추출하여 격자화 하였으며, 아리랑1호 영상으로부터 선구조를 추출하여 l00m 간격으로 버퍼링한 후 격자화 하였다. 이렇게 구축된 산사태 발생 위치 및 발생요인 데이터베이스를 이용, Frequence ratio를 이용하여 각 요소간의 분류를 산사태와의 상관관계를 바탕으로 취약성도를 구하였다. 그리고 계산된 산사태 취약성 지수의 기존 산사태 발생을 설명하는 능력을 정량적으로 표현하기 위하여 추정능력을 계산하였다 또한 이를 교차적용 하여 산사태 취약성도를 각각의 경우에 맞게 만들었다 이러한 평가는 산사태 피해 예방을 위한 방재 사업, 국토개발 계획, 건설계획 등에 기초자료로서 적용 및 활용될 수 있다.

• Spatial Information Research
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• v.16 no.2
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• pp.193-206
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• 2008

If stereo images is used for Digital Elevation Model (DEM) generation, a DEM is generally made by matching left image against right image from stereo images. In stereo matching, tie-points are used as initial match candidate points. The number and distribution of tie-points influence the matching result. DEM made from matching result has errors such as holes, peaks, etc. These errors are usually interpolated by neighbored pixel values. In this paper, we propose the DEM generation method combined with automatic tie-points extraction using existing DEM, image pyramid, and interpolating new DEM using existing DEM for more reliable DEM. For test, we used IKONOS, QuickBird, SPOT5 stereo images and a DTED level 2 data. The test results show that the proposed method automatically makes reliable DEMs. For DEM validation, we compared heights of DEM by proposed method with height of existing DTED level 2 data. In comparison result, RMSE was under than 15 m.

• The Journal of Society for e-Business Studies
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• v.12 no.2
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• pp.47-74
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• 2007

This research purpose to improve the qualification items for electronic commerce manager. Former qualification system for the electronic commerce manager was executed 11 times from year 2000 to 2005. To improve the standard for test questions and contents of qualification items, we reviewed literatures about job analysis for electronic commerce manager, electronic commerce curriculum, e-Business market and other countries' similar qualification systems and items. We also analysed the job related knowledge, skill, and abilities using job analysis by DACUM method, subject matter experts interview and workshop committee for development and validation of qualification items. Based on the results of job analysis and DACUM workshop, we derived a job model for electronic commerce manager and then validated it through field survey and additional expert review. Finally we developed and suggested an alternated qualification items using matrix analysis between categorized job knowledge and job tasks.