• 대한한방소아과학회지
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• 제30권4호
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• pp.60-65
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• 2016

Objectives The purpose of this study is to emphasize the importance of preventing precocious puberty. This study assessed current number of the patients with early puberty and their medical expenses from 2010 to 2015. Methods Using the data from Korean Statistical Information Service and Heathcare Bigdata Hub, number of patients diagnosed with precocious puberty by gender, age, and year from 2010 to 2015 were reviewed. Also, annual medical insurance expenses and the incidence of leuprorelin use were reviewed. Results Number of the patients with precocious puberty has increased from 29,251 in 2010 to 75,945 in 2015. Total medical insurance expenses have increased from 25,716,431 won in 2010 to 56,367,981 won in 2015. The use of lueprorelin also has increased annually from 11,097,590,000 won in 2010 to 21,617,585,000 won in 2015. Conclusions As a result, the patients diagnosed with precocious puberty are increasing in number, and their medical costs have been rising as well. It may be necessary to control the environmental causes of precocious puberty to reduce not only the physical and psychosocial health problems, but also the social costs.

• 대한토목학회논문집
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• 제33권4호
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• pp.1603-1610
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• 2013

화물차 운송의 시간과 비용이 증가하여 물류비가 증가하게 되고 높은 물류비는 결과적으로 산업경쟁력의 저하로 이어지게 되므로 이 연구에서는 물류비 절감을 위해 고속도로에 화물차 전용차로 도입에 관한 연구를 실시하고자 한다. 연구의 대상지는 화물차의 통행이 많은 경부고속도로로 금호 JCT~남구미 IC 구간이고 이 구간에 기본차로, 버스전용차로 설치, 화물차 전용차로 설치, 두 전용차로를 설치시 그에 따른 운행속도, 밀도에 대해 도출하였다. 분석결과 화물차 전용차로 설치시 평균운행속도가 83.4km/h로 가장 높고 밀도는 22.47km/대로 가장 낮은 것으로 나타나 화물차 전용차로 도입시 긍정적인 영향을 미친다고 할 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.129-132
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• 2003

Used cutting fluid from machining processes is harmful to both environment and human health. Chemical substances that provide the lubrication function in the machining process are toxtc to the environment if the cutting fluid is released to soil and water and caused serious health problems to workers who are exposed to the cutting fluid in both liquid and mist form. Recently. cost of using cutting fluid is increasing as the number and the extensiveness of environmental protection laws and regulations increase. Therefore, the use of cutting fluid in machining processes place an enormous burden on manufacturing companies to cover the additional costs associated with their use and protection of our environment. Current trends in manufacturing are focused on minimizing or eliminating the use of metalworking fluids in machining processes. And the increased costs for the disposal of waste products (swarf, coolants and lubricants), especially in industrially developed countries, has generated interest in dry machining. A variety of new techniques are testimony that new technology has rationalized further efforts to research and implement dry machining processes. This paper presents the developed equipment, the process optimization and the applications in the field of surface grinding for the new cryogenic dry machining using a compressed cooling air. The investigated new machining process method shows many advantages compared to conventional techniques with cutting fluid.

• 한국시스템다이내믹스연구
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• 제5권1호
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• pp.49-71
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• 2004

Demand-side Management can be defined as'any utility activity aimed at modifying customers' use of energy to produce desired changes in the utility's load shape'. Customers benefit by being able to control energy costs and improve quality of life and become more productive. Utilities benefit from DSM's value as a resource that enhances asset utilization and reduces both fuel costs and environmental emissions. The scope of DSM includes load management through rate schedules and conservation by improving energy effciency and using electricity consumption effectively. This paper study the DSM resource evaluation and customer behavior analysis todesign the DSM Program plan in response to customer needs. We develop basic system dynamics model to analysis the customer behavior based on a survey research. The DSM Program participants in the Hi- efficiency Inverter, Electric motor and efficient lighting applicancies operating by Conservation program 2002 become the survey objects. DSM resource evaluation evaluate firstt the distribution potentialities of each machine and then forecast the degree of diffusion. We apply the system dynamic approach to simulate the dynamic DSM market situation at the domestic beginning. This model will give the energy Planner the opportunity to create different scenarios for DSM program planning. Also it will lead to increased understanding of the dynamic DSM market

• 자원ㆍ환경경제연구
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• 제19권4호
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• pp.753-769
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• 2010

본 연구에서는 LNG 수입가격과 환율 등 복수의 가격변동 위험이 존재하는 경우 헤징효율성 측면에서 분리헤징과 복합헤징의 비교우위를 실증적으로 분석하였다. 사전적 분석기법을 활용한 실증분석결과에 따르면, 헤징을 하지 않은 경우에 비해 헤징형태에 관계없이 헤징을 통해 조달비용의 평균을 감소시킬 수 있다. 또한 헤징을 통해 표준편차를 감소시킴으로써 보다 안정적인 수익흐름을 확보할 수 있다. 중요한 사실은 분리헤징 형태에 비해 복합헤징 형태로 헤징할 경우 특정 헤징기간에 대해서는 조달비용의 표준편차를 더욱 감소시킬 수 있다는 점이다. 이로써 상품가격과 환율의 위험요소들 사이에 존재하는 분산-공분산 관계를 충분히 활용하는 것이 헤징효과를 향상시키는 데 도움이 될 수 있다는 사실을 확인할 수 있다.

• 자원ㆍ환경경제연구
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• 제25권1호
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• pp.113-140
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• 2016

한 가지의 용량가격만으로는 발전용량 설비투자에 대한 안정적 보상과 시장 기능 유지라는 두 가지 목표를 동시에 달성하기 힘들다. 본 논문은 이런 한계를 극복할 수 있도록 복수의 용량가격을 도입하여 용량가격의 비중을 높이면서 동시에 시장 기능을 유지할 수 있는 이원적 용량가격 제도를 제안한다. 즉, 현재 가스터빈 발전기를 기준으로 하면서 행정적으로 결정되는 용량가격을 그대로 유지하면서, 동시에 LNG복합발전기를 대상으로 한 제2의 용량가격을 도입한다. 이 용량요금은 더 낮은 에너지 가격 상한의 적용을 받으며, 상이한 전원들 사이의 대체관계를 고려한 수요와 용량공급 상황을 반영하도록 설계함으로써 시장 기능을 유지하게 한다.

• 한국유기농업학회지
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• 제22권4호
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• pp.841-854
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• 2014

This study aimed to analyze the selection criteria and priority settings for solid culture medium used in hydroponic crop production in farm households. Expert brain storming was carried out to extract solid culture medium selection criteria for hydroponic farming. As a result, 3 criteria of economy (cost), productivity, and environment, and 9 factors were extracted. A questionnaire survey of hydroponic farm households was conducted in Gyeonggi, Gangwon, and Chooncheong provinces. AHP analysis of the hydroponic solid culture medium selection criteria identified productivity as the most important criterion, chosen by 58.7% of the respondents, followed by economy (28.4%) and environment (12.9%). The 9 factors were rated by the respondents in the following decreasing order of importance: 1, crop yield (28.3%); 2, pest occurrence (18.5%); 3, maintenance/management costs (12.0%); 4, convenience of maintenance/management (13.4%); 5, initial investment cost (11.6%); 6, material energy consumption (6.5%); 7, waste recyclability (4.0%); 8, waste disposal costs (3.4%); and 9 environmental emissions (1.81%). These results imply that hydroponic farm households consider cultivation-related quality factors more important than economic factors, such as price of culture medium or installation cost.

• Advances in aircraft and spacecraft science
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• 제6권5호
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• pp.391-407
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• 2019

Flight trajectory optimization has become an important factor not only to reduce the operational costs (e.g.,, fuel and time related costs) of the airliners but also to reduce the environmental impact (e.g.,, emissions, contrails and noise etc.) caused by the airliners. So far, these factors have been dealt with in the context of 2D and 3D trajectory optimization, which are no longer efficient. Presently, the 4D trajectory optimization is required in order to cope with the current air traffic management (ATM). This study deals with a cubic spline approximation method for solving 4D trajectory optimization problem (TOP). The state vector, its time derivative and control vector are parameterized using cubic spline interpolation (CSI). Consequently, the objective function and constraints are expressed as functions of the value of state and control at the temporal nodes, this representation transforms the TOP into nonlinear programming problem (NLP). The proposed method is successfully applied to the generation of a minimum length optimal trajectories along 4D waypoints, where the method generated smooth 4D optimal trajectories with very accurate results.

• 한국인공지능학회지
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• 제10권1호
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• pp.9-14
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• 2022

The demand for public bicycles operated by the Seoul Metropolitan Government is increasing every year. The size of the Seoul public bicycle project, which first started with about 5,600 units, increased to 3,7500 units as of September 2021, and the number of members is also increasing every year. However, as the size of the project grows, excessive budget spending and deficit problems are emerging for public bicycle projects, and new bicycles, rental office costs, and bicycle maintenance costs are blamed for the deficit. In this paper, the Azure Machine Learning Studio program and the Boosted Decision Tree Regression technique are used to predict the number of public bicycle rental over environmental factors and time. Predicted results it was confirmed that the demand for public bicycles was high in the season except for winter, and the demand for public bicycles was the highest at 6 p.m. In addition, in this paper compare four additional regression algorithms in addition to the Boosted Decision Tree Regression algorithm to measure algorithm performance. The results showed high accuracy in the order of the First Boosted Decision Tree Regression Algorithm (0.878802), second Decision Forest Regression (0.838232), third Poison Regression (0.62699), and fourth Linear Regression (0.618773). Based on these predictions, it is expected that more public bicycles will be placed at rental stations near public transportation to meet the growing demand for commuting hours and that more bicycles will be placed in rental stations in summer than winter and the life of bicycles can be extended in winter.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1106-1113
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• 2022

Cost segregation helps reduce tax liabilities by reclassifying real property to personal property and accelerates tax depreciation of a property. A typical cost segregation study requires much time and high costs. This study proposed a BIM integrated cost segregation process that can be applied to any commercial building project. The proposed BIM-based cost segregation process was verified in a new commercial construction project. It approved that this approach can: (1) increase the cash flow for the owner and provide assistance to tax-paying enterprises; (2) enable the contractor to use it as an added value in the bidding process; (3) realize data sharing in a common platform to improve the cost segregation study efficiency and reduce costs and errors; (4) contribute to the asset management in the life cycle of buildings while filling in the blank of cost segregation process. Future studies will focus on the automation of cost segregation and asset management in building construction's life cycle.