• Safety and Health at Work
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• 제14권1호
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• pp.59-65
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• 2023

Objectives: Epidemiological evidence linking long working hours and shift work to metabolic syndrome remains inadequate. We sought to evaluate the impact of reducing working hours on metabolic syndrome. Methods: We compared the prevalence of metabolic syndrome among male manual workers in a manufacturing company (N = 371) before and after the introduction of policy to reduce daily work hours from 10 to 8 hours. Components of metabolic syndrome were measured in periodic health examinations before the intervention, 6-9 months after, and 1.5-2 years after the intervention. Generalized estimating equation models were used to estimate changes in the prevalence of metabolic syndrome. Analyses were stratified by day work versus shift work. Results: The results showed a significantly decreased prevalence of metabolic syndrome 6-9 months following the intervention in day workers (risk ratio = 0.68, 95% confidence interval 0.52-0.88), but the benefit disappeared after 1.5-2 years. Shift workers showed a decreased prevalence of metabolic syndrome for the whole follow-up duration after the intervention, although the change was not statistically significant. Conclusion: Reducing working hours was associated with short-term improvement in metabolic syndrome in male manual workers.

• 한국농공학회지
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• 제26권4호
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• pp.52-65
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• 1984

In general precise estimation of hourly of daily distribution of the long-term run-off should be very important in a design of source of irrigation. However, there have not been a satisfying method for forecasting of stationar'y long-term run-off in Korea. Solving this problem, this study introduces unit-hydrograph method frequently used in short-term run-off analysis into the long-term run-off analysis, of which model basin was selected to be Sumgin-river catchment area. In the estimation of effective rainfall, conventional method neglects the Soil moisture condition of catchment area, but in this study, the initial discharge (qb) occurred just before rising phase of the hydrograph was selected as the index of a basin soil moisture condition and then introduced as 3rd variable in the analysis of the reationship between cumulative rainfall and cumulative loss of rainfall, which built a new type of separation method of effective rainfall. In next step, in order to normalize significant potential error included in hydrological data, especially in vast catchment area, Snyder's correlation method was applied. A key to solution in this study is multiple correlation method or multiple regressional analysis, which is primarily based on the method of least squres and which is solved by the form of systems of linear equations. And for verification of the change of characteristics of unit hydrograph according to the variation of a various kind of hydrological charateristics (for example, precipitation, tree cover, soil condition, etc),seasonal unit hydrograph models of dry season(autumn, winter), semi-dry season (spring), rainy season (summer) were made respectively. The results obtained in this study were summarized as follows; 1.During the test period of 1966-1971, effective rainfall was estimated for the total 114 run-off hydrograph. From this estimation results, relative error of estimation to the ovservation value was 6%, -which is mush smaller than 12% of the error of conventional method. 2.During the test period, daily distribution of long-term run-off discharge was estimated by the unit hydrograph model. From this estimation results, relative error of estimation by the application of standard unit hydrograph model was 12%. When estimating by each seasonal unit bydrograph model, the relative error was 14% during dry season 10% during semi-dry season and 7% during rainy season, which is much smaller than 37% of conventional method. Summing up the analysis results obtained above, it is convinced that qb-index method of this study for the estimation of effective rainfall be preciser than any other method developed before. Because even recently no method has been developed for the estimation of daily distribution of long-term run-off dicharge, therefore estimation value by unit hydrograph model was only compared with that due to kaziyama method which estimates monthly run-off discharge. However this method due to this study turns out to have high accuracy. If specially mentioned from the results of this study, there is no need to use each seasonal unit hydrograph model separately except the case of semi-dry season. The author hopes to analyze the latter case in future sudies.

• 항공우주시스템공학회지
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• 제9권2호
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• pp.25-33
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• 2015

Global market of unmanned aircraft(UA) is rapidly expending based on the versatile and efficient utility of the UA. Domestically many industries, universities and research institutes are trying to do research and development of the UA in various angle of aspect. In spite of these effort, all the participants of research and development of the UA has been suffering the difficulty of acquiring the airspace around vicinity of Goheung airfield for the flight test of UA. Although the current procedure of execution of the flight test of UA is set after acquiring the airspace by applying the NOTAM(Notice To Air Man) to the Ministry of Land, Infrastructure and Transport(MLIT) at least 7 days before the flight test and commencing with the publication of the NOTAM by MLIT, if the flight test is carried out as planned, changing or reapplying the NOTAM expends mort time and makes difficulty often. Therefore it is needed that a restricted airspace for the flight test of UA is established and make all the executioner of flight test uses the exclusive airspace without limitation. This research proposes the restricted airspace with short term and long term establish requirement of airspace separately. The short term requirement has been established with the airspace of 10 nm radius and 8,000 ft altitude in which the requirements of flight test can be carried out more than 90% without needs of supplement of the additional airspace. The long term has been established within the airspace of 30 nm radius which is the maximum Radio Line Of Sight(RLOS) and 8,000 ft altitude with exclusion of current air way, airport control area, approaching corridor to the airport, existing restricted area(RA) and Military Operating Area(MOA) for the purpose of minimizing inconvenience of the other airspace user. Once establishing the exclusive airspace for the flight test of UA, research and development of industries, universities and research institutes will be more vigorous and contributes to the national economy.

• 환경영향평가
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• 제21권1호
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• pp.185-199
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• 2012

Ecotourism has been attracting much attention as an example industry that can vitalize local economy markets and preserve natural resources. Implementation of 'Ecotourism Designation System' is under consideration to provide ecotourism products that can both emphasize the original meanings of ecotourism and ensure stronger trust from customers than ever before. This research introduced the direction, principles, subjects, and assessment indicators by subjects in terms of implementing the system and proposed fundamentals for both designation assignment and score calculation. In the face of implementing such a system in Korea, the investigation sought subjects whose target areas and programs are in need of examination. For assessment criteria by subjects, six assessment indicators were selected in the end for ecotourism sites, including: (1) the value of natural/ecological preservation (2) facility's ecological design (3) understanding both the environment and local culture (4) systems connecting local communities for cooperation (5) long/short term preservation and maintenance strategies/plans (6) willingness to further develop ecotourism and cooperative platform. In addition, seven assessment indicators were selected for program assignments, including: (1) the value of natural/ecological preservation (2) minimization of environmental effects (3) expansion of environmental understanding (4) sharing the local culture (5) vitalizing local connections and economical activities among communities (6) securing and maintaining professionality among human resources (7) odds of continuation, creativity, and aptness to improve programs. After considering the pros and cons of both categorizing system and yes/no system, implementation of categorizing system for the short term and yes/no for the long term were suggested, followed by additional suggestions of a score calculation system for each system. The official implementation of the 'Ecotourism Designation System' is scheduled for launch in 2013 after the trial operation in 2012. The assessment indicators and fundamentals suggested in this research, considering judgment, must be improved via systematic and practical methods through the trial operation.

• 농업과학연구
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• 제46권1호
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• pp.67-78
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• 2019

The purpose of this study was to predict the water quality using the RNN (recurrent neutral network) and LSTM (long short-term memory). These are advanced forms of machine learning algorithms that are better suited for time series learning compared to artificial neural networks; however, they have not been investigated before for water quality prediction. Three water quality indexes, the BOD (biochemical oxygen demand), COD (chemical oxygen demand), and SS (suspended solids) are predicted by the RNN and LSTM. TensorFlow, an open source library developed by Google, was used to implement the machine learning algorithm. The Okcheon observation point in the Geum River basin in the Republic of Korea was selected as the target point for the prediction of the water quality. Ten years of daily observed meteorological (daily temperature and daily wind speed) and hydrological (water level and flow discharge) data were used as the inputs, and irregularly observed water quality (BOD, COD, and SS) data were used as the learning materials. The irregularly observed water quality data were converted into daily data with the linear interpolation method. The water quality after one day was predicted by the machine learning algorithm, and it was found that a water quality prediction is possible with high accuracy compared to existing physical modeling results in the prediction of the BOD, COD, and SS, which are very non-linear. The sequence length and iteration were changed to compare the performances of the algorithms.

• 콘크리트학회지
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• 제3권4호
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• pp.107-115
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• 1991

플라이애쉬를 혼입한 고강도 콘크리트의 초기 및 장기 강도 특성과 작업성 특성에 관한 연구를 수행하였다. 이를 위하여 강도 수준이 다른 6종류의 기본 배합을 선정하고 각 기본 배합을 선정하고 각 기본 배합에 대하여 플라이애쉬 첨가량을 0, 10, 20, 30%로 변화시켜 가면서 그 특성을 실험하였다. 또한, 고강도 플라이애쉬 콘크리트의 슬럼프 감소현상을 분석하기 위하여 4종류의 배합을 추가하여 실험하였다. 연구 결과, 제2종 포틀랜드 시멘트를 사용한 경우, 플라이애쉬를 10%혼입한 콘크리트는 대부분 28일 이전에 일반 콘크리트보다 높은 강도를 발현하였다. 또한, 플라이애쉬 첨가량이 증가함에 따라 보통강도 콘크리트의 슬럼프값은 감소하였으며, 고강도 콘크리트의 슬럼프값을 일정하게 유지시키기 위해서는 더 많은 양의 고유동화제가 사용되었다.

• 한국의류산업학회지
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• 제10권2호
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• pp.138-146
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• 2008

Opera costumes are a tangible medium to directly affect how opera singers performed. Therefore, stage costumes have been designed in various ways to reflect intentions of directors. This study examines modernization of opera costumes. For this study, the author worked as one of costume design staff for "Faust" which was played in Sung-Nam Art Center from November 24, 2005 to November 27, 2005 in commemoration of the opening of the center. The following outcomes of the supporting actors are drawn from this study. Martha wore a grey jacket and a long skirt with slash. Grey suit symbolized chastity but tight long skirt with slash means sexy. Valentin wore military and combat uniforms to express that he was a soldier. The military uniform represented the situation before the war and the combat uniform symbolized the situation after the war. Rather short trousers, a white tweed jacket, purple flower ornament, a light green vest, and a beret were used to express Wagner, who looked ridiculous and always tried to flirt. Overalls, a blue jumper, and a scarlet baseball cap were used to make Siebel look naive and homely. Modern opera costumes now help reduce the time and space between stage and audience, improve economic efficiency and meet the audience's needs for various style.

• The Journal of Asian Finance, Economics and Business
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• 제5권4호
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• pp.201-211
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• 2018

The paper suggests making a policy and strategies for a way of exporting Korean ICT product effectively in the EU and Eastern area, and an effective preparation of 4^th industrial revolution through analysis of preparation status of 4^th industrial revolution of the Visegrad group. Analyze policy, status, what they want for 4^th preparation in the Visegrad group from comparing characteristics analysis of each country's official data, publication data, portal, paper, and etc. They have been preparing for 4^th industrial revolution long time ago as basic research and business before 4^th wave word. With these basic results, they are trying to apply such as, AI, S/W, security, ICT, etc. of 4^th wave core technology. For the development of new export market in EU, the Korean team should research with university and research center or venture company. Through these cooperation, they should understand their personal characteristic, lifestyle, and what consumers want to purchase in EU. And this results can be used in South Asia and India that give a big effect to all over the world ICT market. The external impact of the 4^th wave must have a long-term shift in manpower, and production policy is related to the EU's strategic role, or the preparation of the 4^th wave to the V4 country in the short term.

• 한국항만경제학회지
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• 제17권1호
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• pp.3-26
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• 2001

Competitive and reliable maritime transport services benefit the economy as a whole, and are key efficiency factors for the production of both goods and services. Although maritime transport sector is very liberalized compared to many other service sectors, certain obstacles must be overcome before full liberalization of the maritime transport can be realized. Particularly, maritime transport services in Northeast Asia are regulated by a complicated and outdated system. To remove these barkers two approaches can be used: a regional trading arrangement approach and a multilateral approach via WTO. However, multilateral efforts are not likely to be successful in achieving any concrete progress towards maritime transport liberalization in the short- to medium-term in Northeast Asia. Consequently, it may be the best to take the following two progressive approaches and to make them work towards liberalization of the maritime transport market: a bilateral approach and a trilateral approach. A gradual process of liberalization would expand the market, help operators achieve economies of scale, promote the international division of labor and specialization, enhance the effective management of shipping services, and promote the long-term interests and welfare of the user by improving service quality and diversifying services. A liberalized and integrated maritime transport market in Northeast Asia should achieve both of these long-run policy objectives by benefiting both the transport service users and the transport service providers. In order to move the maritime transport liberalization programs as quickly as possible, it is desirable to establish a "Regional Maritime Transport Liberalization Committee." We suggest it to be a Tripartite (China, Japan and Korea) Committee initially, which can later expand its membership to include other Northeast Asian countries.

• 산업경영시스템학회지
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• 제42권2호
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• pp.78-85
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• 2019

High variance observed in the measurement system can cause high process variation that can affect process capability badly. Therefore, measurement system analysis is closely related to process capability analysis. Generally, the evaluation for measurement system and process variance is performed separately in the industry. That is, the measurement system analysis is implemented before process monitoring, process capability and process performance analysis even though these analyses are closely related. This paper presents the effective concurrent evaluation procedure for measurement system analysis and process capability analysis using the table that contains Process Performance (Pp), Gage Repeatability & Reproducibility (%R&R) and Number of Distinct Categories (NDC). Furthermore, the long-term process capability index (Pp), which takes into account both gage variance and process variance, is used instead of the short-term process capability (Cp) considering only process variance. The long-term capability index can reflect well the relationship between the measurement system and process capability. The quality measurement and improvement guidelines by region scale are also described in detail. In conclusion, this research proposes the procedure that can execute the measurement system analysis and process capability analysis at the same time. The proposed procedure can contribute to reduction of the measurement staff's effort and to improvement of accurate evaluation.