• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8700-8706
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• 2015

The first driving device of the power bogies for the Korean high-speed railway vehicle consists of the traction motor (TM) and the motor reduction gears unit (MRU). Although TM and MRU are the mechanically integrated structures, their time between overhauls (TBO) have two separate intervals due to different technical requirements(i.e. TBO of MRU: $1.8{\times}10^6km$, TBO of TM: $2.5{\times}10^6km$). Therefore, to reduce the unnecessary number of preventive maintenances, it is important to evaluate the optimal TBO with a viewpoint of reliability-center maintenance towards cost-effective solution. In this study, derived from the field data in maintenance, fault tree analysis and failure rate of the subsystem considering criticality of the components are evaluated respectively. To minimize the conventional total maintenance cost, the same optimal TBO of the components is derived from genetic algorithm considering target reliability and improvement factor. In this algorithm, a chromosome which comprised of each individual is the minimum preventive maintenance interval. The fitness function of the individual in generation is acquired through the formulation using an inverse number of the total maintenance cost. Whereas the lowest common multiple method produces only a four percent reduction compared to what the existing method did, the optimal TBO of them using genetic algorithm is $2.25{\times}10^6$km, which is reduced to about 14% comparing the conventional method.

• Journal of Korean Society of Transportation
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• v.20 no.1
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• pp.55-63
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• 2002

It has been known well that Traffic Conflict Technique(TCT) used to evaluate the safety of intersections in the case of shortage of traffic accidents data and surveying time. Because data for using in traffic conflict technique that is collected by trained surveyors, it is rely on the knowledge, experience and the characteristics of them. The data of surveying generate varying result. So, its variance must minimize and then it is considered of calculating in traffic conflict technique however obviously technique to minimize has not developed until now. So, this paper has a focus on the technical method to minimize the variance. For this, it applied the fuzzy reasoning theory to the existed traffic conflict technique that is the most comprehensive method in the country and then developed the new traffic conflict technique model. Fuzzy reasoning theory is a very appropriate method for minimizing the variance among surveyors because it can systematically calculate the uncertainty of surveyors by approximation reasoning structure. The result of analysis from pilot study, the new Procedure in this Paper minimized the variance by 53 Percentiles and it increased the value of conversion factor two times than the exited traffic conflict technique. The method proposed in this paper, it can be used for evaluating the safety of intersection, and before and after analysis of improving Project of black spots.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.825-830
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• 2009

Pharmaceutical compounds enter the water environment through the diverse pathways. Because their concentration in the water environment was frequently detected in the level of ppt to ppb, the monitoring system should be optimized as much as possible for finding appropriate management policies and technical solutions. One Factor At a Time (OFAT) approach approximating the response with a single variable has been preferred for the optimization of LC-MS/MS operational conditions. However, it is common that variables in analytical instruments are interdependent. Therefore, the best condition could be found by using the statistical optimization method changing multiple variables at a time. In this research, response surface analysis (RSA) was applied to the LC-MS/MS analysis of emerging antibiotic compound, sulfamethoxazole, for the best sensitivity. In the screening test, fragmentation energy and collision voltage were selected as independent variables. They were changed simultaneously for the statistical optimization and a polynomial equation was fit to the data set. The correlation coefficient, $R^2$ valuerepresented 0.9947 and the error between the predicted and observed value showed only 3.41% at the random condition, fragmentation energy of 60 and collision voltage of 17 eV. Therefore, it was concluded that the model derived by RSA successfully predict the response. The optimal conditions identified by the model were fragmentation energy of 116.6 and collision voltage of 10.9 eV. This RSA can be extensively utilized for optimizing conditions of solid-phase extraction and liquid chromatography.

• The Research Journal of the Costume Culture
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• v.4 no.3
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• pp.305-323
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• 1996

The purpose of this sty is to forecast the tendency of clothing colors, to provide materials useful for making the color plan for a better costume, and suggest new information in the apparel industry. To achieve these purposes, this study was carried out by suggesting vogue colors of recent apparel, along with the 20 standard colors of Muncell to 350 men and women in their 20s residing in Taegu.. We analysed and compared their preferred colors in suits vidual factor ;age, sex, education ,skin color, and body shape, and additionally classifying their interest in clothing colors, cause for color selection , degree of interest in color of clothes, color satisfaction of apparel market, and color combination of clothing, color satisfaction of apparel market, and color combination of clothing. We compared these elements according to their age, sex, and education. The results of this study is summarized as follows; 1. It was shown that both men and women in their 20s preferred warm colors the first colors mentioned being the most popular ; Pastels, Red, Blue and Black. They disliked dark and sordid colros in the order of Mauve, Khaki and Red. They preferred wearing Pastels and Yellow in the Spring, White, Blue, and Pastels were the favorites for summer, Beige in autumn, and black, Gray, and Beige in winter. The repugnated colors they chose two wear were Black, Red, Mauve, Khaki in spring and summer. Mauve, Red, Yellow were favorites for autumn, and Blue·White, Yellow·Green, and Pastels in winter. 2. The preferred colors for T-shirts were Yellow, Pastels, White in spring. White and Pastels were summer favorites, Beige an Red for autumn, and Black, Red, Beige in Winter. As for suits, the preferred colors in spring were in the order of Pastels, Beige and Yellow. The preferred colors of upper garments in summer were in the order of White and pastels. for lower summer garments Pastels, White and Blue were favorites. In autumn, Beige was shown to be highly preferred, and in winter, the order of preferred colors was Black, Gray and Beige. 3. On of those individual factors showing the greatest difference was sex. 4. Those factors having the greatest impact on the selection of clothing color were the season and their preference color. 5. The in vogue color of men in their 20s was at a higher level than hat of women. The groups that had an upper college level education showed a significant difference in their choices thant hose who were highschool graduates and technical college student and graduates. The consideration of inteterest in color of clothes, holding clothes during new purchasing, body shape and skin color was higher for women than men. In buying and wearing accessaries, women tend to take into consideration the harmony with the garment, and there was shown a significant difference between highschool graduates and the groups above the level of college education.

• Journal of the Korean Geotechnical Society
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• v.21 no.3
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• pp.159-168
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• 2005

In the previous studies, settlement behaviors of granular compaction piles have generally been analyzed with an evaluation of the settlement reduction factor based on tile load-sharing ratio and the replacement ratio. In this approach, however, since the reinforced ground with granular compaction piles is simplified as the composite ground, only the difference of a relative vertical strength between piles and soils is taken into account without reflecting lateral behaviors of granular compaction piles. In the companion research paper, the method of estimating the settlement of granular compaction piles was proposed by synthetically considering a vertical strength of the ground, lateral behaviors of granular compaction piles, the strength of pile materials, a pile diameter, and an installation distance of the pile. In the presented study, to validate a propriety of the previously proposed method, large scale field load tests and three dimensional numerical analyses are performed. The results are analyzed in detail and compared with the predicted settlements by the proposed method. Finally, a simple method to estimate the settlement of granular compaction piles is suggested for an easy application of the practical design.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.402-407
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• 2010

Introduction: The planning of implant surgery is an important factor for the implant prosthesis. Stereolithographic (SLA) surgical stents based on a computer simulation are quite helpful for clinicians to perform the surgery as planned. Although many clinical and technical trials have been performed for computed tomography (CT)-guided implant stents to improve the surgical procedures and prosthetic treatment, there are still many problems to solve. We developed a system of a surgical guide based on 3 dimensional (3D) CT for implant therapy and achieved satisfactory results in the terms of planning and operation. Materials and Methods: Fifteen patients were selected and 30 implant fixtures were installed. The preoperative CT data for surgical planning were prepared after obtaining informed consent. Surgical planning was performed using the simulation program, Ondemend3D In2Guide. The stents were fabricated based on the simulation data containing information of the residual bone, the location of the nerve, and the expected design of the prostheses. After surgery with these customized stents, the accuracy and reproducibility of implant surgery were evaluated based on the computer simulation. The data of postoperative CT were used to confirm this system using the image fusion technique and compare the implant fixtures between the planned and implanted. Results: The mean error was 1.18 (${\pm}0.73$) mm at the occlusal center, 1.23 (${\pm}0.67$) mm at the apical center, and the axis error between the two fixtures was $3.25^{\circ}C$ (${\pm}3.00$). These stents showed superior accuracy in maxilla cases. The lateral side error at the apical center was significantly different from the error at the occlusal center but there were no significant differences between the premolars, 1st molars and 2nd molars. Conclusion: SLA surgical stents based on a computer simulation have the satisfactory accuracy and are expected to be useful for accurate planning and surgery if some errors can be improved.

• Journal of Radiation Protection and Research
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• v.22 no.2
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• pp.111-117
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• 1997

Recently, the conclusion of Comprehensive Test Ban Treaty(CTBT) is globally constructing a network system for nuclear test monitoring. The radionuclide experts of the Conference on Disarmament recommended that the detection of nuclear debris in the atmosphere was an essential factor of nuclear test monitoring and proposed the technical requirements. Based on those requirements, atmospheric radionuclide monitoring system to detect nuclear debris generated from the nuclear explosion test was composed. The system is comprised of high volume air sampler(HVAS), filter paper presser and high purity germanium detector(HPGe). Minimum detectable concentrations(MDCs) of the key nuclides requiring in CTBT monitoring strategies are determined by considering of decay time, counting time and flow rate of the high volume air sampler for the rapid explosion and the optimum measurement condition. The results were selected $10{\pm}$2h, $20{\pm}$2h and $850{\pm}50m^3$/h as parameters, respectively. The relation between the natural air-borne radionuclide concentration of $^{212}Pb$ and MDC were calculated which gave effect in the Compton continuum baseline due to those nuclides in the gamma-ray spectroscopy. These results can be used as an actually tool in the CTBT monitoring strategies.

• Korean Journal of Occupational Health Nursing
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• v.6 no.2
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• pp.156-167
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• 1997

In Korea, based on the Revised Law of Occupational Safety and Health a new entity of institution was set up in 1990 to provide occupational health services to SSE in which three sorts of personnel as a team have to be involved. These institutions, in charge of scores to hundreds of workplace area-wide, have been providing occupational health services without payment from employers or employees, and government reimburses through the Occupational Injury Prevention Insurance since 1993. As a service provider, a team is composed of doctors, nurses and industrial hygienists. Undergraduate and postgraduate educations for the SSE occupational health are not specified and the question on the performance of the personnel has been raised. This study was designed to analyze the facilitating factors of and barriers to the performance and its improvement of these personnel. In 1997, the survey was conducted with all 58 institutions. Structured questionnaires were mailed to 200 personnel who were providing the occupational health service for SSE. The response rate was 51.7% for doctors, 58.6% for nurses, and 60.3% for industrial hygienist, respectively. Results are as follows : 1) There is a guideline for occupational service mandated by the government. Under the guideline, the minimum frequency of visiting workplace is assured with six times of doctors, 17 times for nurse and industrial hygienist in a year. There are one doctor for every 200 factories, one nurse and one hygienist for every 100 factories. 2) All respondents have basic qualification for occupational health service. About 16.7%. of doctors are certified in industrial medicine or preventive medicine, and 64.7% of industrial hygienists had first grade certification. Totally 66.7% of personnel have been involved in occupational health for more than one year. 3) As a support system for the performance improvement, 66.3% respond that they have been provided with educational materials, advice related to industrial environment and guidance of MSDS from Korea Industrial Safety Corporation. Most respondents indicate the lack of concern of employers and employees as a main barrier to the improvement of the service. Also they are in the need of the training opportunity more focused on SSE. The Governments policy for SSE is a principal facilitating factor. Training program focused on SSE situation, manpower, technical support, etc. are areas to be improved to have a better occupational health service for SSE in Korea.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.115-125
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• 2015

The purpose of this study is to empirically examines the effects of corporate sustainable management activities(social activity, economic activity, environmental activity) on the innovation activities(managerial innovation, technical innovation) in the convergence era. To accomplish these purposes, their relationships were modeled based on the previous studies conducted in the various areas. A total of 500 questionnaires were distributed to the employees working at the small & medium size companies. The statistical techniques such as descriptive analysis, reliability analysis, factor analysis, correlation analysis, multi regression analysis were used to evaluate the research model. The results of multi regression analysis show that all three aspects of corporate sustainable management activities have positively significant effects on the two factors of innovation. That is, if each activities of sustainable management works properly, it leads to create innovation. In addition, enterprises are needed to develop training programs or action planning that make the employees understands sustainable management well. Thus, the advanced level of corporate sustainability is expected if various sustainable management activities are performed in harmony with their innovation activities.

• Korean Journal of Health Education and Promotion
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• v.8 no.1
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• pp.68-86
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• 1991

This study was carried out to investigate consciousness level of physical exercise and analyze factors affection to the practice of exercise. The main purpose of the study was to give basic and necessary data in developing of program regarding to the physical exercise of the people and social athletics. This study was conducted by trained surveyers, for dweller in three cities(Seoul, Taegu and Ulsan) during January 4. 1990 to January 24. 1990. The results of this study can be summarized as follows 1. The subject of criticism an investigation for general charactristic be conducted in Seoul, Taegu and Ulsan city area an objective 417 person, 432 person and 366 person was among those comparatively little more by male was higher rate than female. Those in classification was adopted by age group 20 years old adult 41.3% of most higher rate, age group evaluation, were 24.9％ and other group were 18.4％ comprehensively appearanced by adult group has most many value rate. 2. An objective of investigation survey was made to personnel were comparative an educated level significantly higher such as college graduated 48.8％ this rate of value has most higher, High school graduated ; 30.1％ and middle School gratuated were 11.7％. In addition the native comes from large city, Farming and fishing villages an rural area rate were shown as 29.6％, 28.4% and 19.9% each other. There by classification of occupational job was shown by students has 27.4％ are most higher significantly, also there sales and service field job appearanced 15.1％ and expert technical job is 9.0% Although nonreligion person rate were 37.3%, buddist, Christianity, Roman Catholicism all them each other shown 33.6％, 16.7％ and 12.4%. An evaluation in economic situation value rate was appearanced by middle class level 61.7％ and higher and low level are 14.4％ and 23.9% with each other and married were 59.2％. 3. The people resident in cities area has pratice of health development by exercise person were 43.5% and value of rate for male has exercise practice is 52.5％, was significantly higher than female has by age group 10 years old and age group 50 years old is 52.6％ and 47.3％ was comparative higher rate also age group 30 is 35.1％ of low factor was indicated. Although evaluated an economic situation rate was higher level get more taken the practice of health develop exercise(higher level 60.0％ and low level is 32.9％). Although by higher level of educated were more taken pratice of their proper physical exercise(college graduated rate ; 52.2％ of most higher and high school graduted ; 39.7％ and then middle school graduated is 19.1％) unmarried taken exercise rate ; 48.4％ is significantly higher than married person rate ; 40.8％. Although objective of native area of exercise rate of Urban area cities ; 52.5％ are significantly higher farming and fishing native person rate ; 40.4％ shown is most low.