• 한국산학기술학회논문지
• /
• 제20권2호
• /
• pp.763-772
• /
• 2019

최근 TOD에 대한 지속적인 효과를 기대하고 실제 도시계획 및 설계에 적용되고 있다. 그러나 그것의 효과를 정량적으로 평가할 방법에 대한 연구는 미미한 실정이다. 그래서 본 연구의 목적은 TOD의 차량 통행 감소 효과를 도시계획 단계에서 토지이용계획도를 기반으로 정량적으로 평가하는 방법을 제안하는 것이다. 이를 위해서 토지이용계획도에 포함된 정보를 네트워크로 변환하는 방법과 네트워크를 기반으로 이동발생량을 추정하는 방법을 제안한다. 첫 번째 단계에서는 토지이용계획도의 도로망을 링크로, 도로의 교차점을 노드로 변환한다. 토지이용계획도에 포함된 구역의 면적과 구역별 높이는 인접노드에 가중치로 변환된다. 두 번째 단계에서는 네트워크상의 노드 간에 가중치에 비례한 빈도로 이동이 발생하는 것을 가정하여 이동발생량을 보행과 차량으로 구분하여 추정한다. 그다음 TOD를 본격적으로 적용하지 않은 도시를 대상으로 현재 도시와 TOD를 적용하여 재설계한 도시를 비교하여 TOD의 효과를 분석한다. 본 연구에서는 이와 같은 방법을 1997년 계획 당시 분당과 TOD를 적용하여 재설계한 가상 대안에 적용한 결과, 39.94% 정도의 차량 통행 감소 효과가 발생함을 확인하였다. 또한, TOD를 적용한 대안의 보행율이 2.39%로 현황보다 증가하고 있음을 알 수 있다.

• 한국지반환경공학회 논문집
• /
• 제22권2호
• /
• pp.25-33
• /
• 2021

본 연구는 토석류의 퇴적 특성을 파악하고 소단을 설치함에 따른 토석류 피해의 저감효과를 분석하기 위해 수행되었다. 다양한 수로경사 및 토사체적농도를 고려하여 수로실험을 수행하였으며, 소단 설치에 따른 토석류 피해의 저감효과를 분석하기 위해 소단을 설치하지 않은 경우와 소단을 설치한 경우를 비교하였다. 본 연구에서는 토석류의 퇴적 특성 중 도달거리, 총 이동거리 및 이동비에 대한 분석을 진행하였다. 먼저 수로경사 변화에 따른 토석류의 퇴적 특성을 분석하였고, 토사체적농도 변화에 따른 토석류의 퇴적 특성을 분석하였다. 또한, 소단을 설치하지 않은 경우를 기준으로 소단을 설치한 경우의 퇴적 특성 변화율을 산정하였다. 실험결과, 수로경사와 토사체적농도가 토석류의 퇴적 특성에 상당한 영향을 미치는 것을 확인하였다. 또한, 사면에 소단을 설치할 경우 토석류의 도달거리와 이동비가 크게 감소하였으며, 총 이동거리가 증가하였다. 이는 소단을 설치하는 것이 토석류의 이동을 지연시키고, 토석류의 잠재적인 이동성을 감소시키는 것을 의미한다. 본 연구의 결과는 토석류의 퇴적 특성을 이해하는 데 유용한 정보를 제공할 것이며, 나아가 소단의 설계에 도움을 줄 것으로 기대된다.

• 인터넷정보학회논문지
• /
• 제16권6호
• /
• pp.57-67
• /
• 2015

This paper proposes an Fuzzy-based Risk Reasoning Driving Strategy on VANET. Its first reasoning phase consists of a WC_risk reasoning that reasons the risk by using limited road factors such as current weather, density, accident, and construction, a DR_risk reasoning that reasons the risk by combining the driving resistance with the weight value suitable for the environment of highways and national roads, a DS_risk reasoning that judges the collision risk by using the travel direction, speed. and distance of vehicles and pedestrians, and a Total_risk reasoning that computes a final risk by using the three above-mentioned reasoning. Its second speed reduction proposal phase decides the reduction ratio according to the result of Total_risk and the reduction ratio by comparing the regulation speed of road to current vehicle's speed. Its third risk notification phase works in case current driving speed exceeds regulation speed or in case the Total_risk is higher than AV(Average Value). The Risk Notification Phase informs rear vehicles or pedestrians around of a risk according to drivers's response. If drivers use a brake according to the proposed speed reduction, the precedent vehicles transfers Risk Notification Messages to rear vehicles. If they don't use a brake, a current driving vehicle transfers a Risk Message to pedestrians. Therefore, this paper not only prevents collision accident beforehand by reasoning the risk happening to pedestrians and vehicles but also decreases the loss of various resources by reducing traffic jam.

• 보건행정학회지
• /
• 제9권3호
• /
• pp.70-94
• /
• 1999

This paper was performed for a cost-effectiveness analysis of pharmacologic treatment of hypercholesterolemia. Agents modeled were cholestyramine, gemfibrozil. bezafibrate, lovastatin, pravastatin, simvastatin. Pharmacologic effectiveness was estimated by regression from reported clinical trials. Pharmacologic effects were expressed as the percent change of blood cholesterol level. Cost estimates included patients' travel expenses and time loss as well as resource consumption in the health care sector. Bezafibrate was the most efficient agent for reducing total cholesterol levels, having an cost over 1 year of ￦31.400 per percent reduction in total cholesterol. Simvastatin (10mg/d) was also efficient(￦33,100 per percent reduction). Chole styramine(8g/d) was least efficient at ￦90,200. For low-density lipoprotein cholesterol. simvastatin(10mg/d) was most efficient, at ￦23,200 per percent reduction, followed by lovastatin(20mg/d) at ￦28,000. Gemfibrozil was least efficient at ￦77,800 per percent reduction. For high-density lipoprotein cholesterol. bezafibrate(400mg/d) was most efficient at ￦39,300 per percent increase of high-density lipoprotein cholesterol. Cholestyramine was least efficient at ￦514,700. Analyses combining low-density lipoprotein cholesterol and high-density cholesterol effects suggest that bezafibrate(600mg/d) and simvastatin (10mg/d) were most efficient for reducing cardiovascular risk. The cost-effectiveness analysis results show that both simvastatin and bezafibrate could be efficient treatment. Simvastatin provide more effective treatment at higher cost, whereas bezafibrate is more cost-effective, as it may be less effective, at lower cost. Therefore, clinicians should choose reasonable treatment according to the patient's needs This pharmacoeconimc analysis will provide a guideline for efficient pharmacologic treatment and also be reference data for pricing new drugs.

• International Journal of Aeronautical and Space Sciences
• /
• 제15권1호
• /
• pp.97-101
• /
• 2014

With the increase in global air travel, aircraft noise has become a major public issue. In modern aircraft engines, only a small proportion of the air that passes through the whole engine actually goes through the core of the engine, the rest passes around it down the bypass duct. A successful method of reducing noise further, even in ultra-high bypass ratio engines, is to absorb the sound created within the engine. Acoustically absorbent material or acoustic liners have desirable acoustic attenuation properties and thus are commonly used to reduce noise in jet engines. The liners typically are placed upstream and downstream of the rotors (fans) to absorb sound before it propagates out of the inlet and exhaust ducts. Noise attenuation can be dramatically improved by increasing the area over which a noise reducing material is applied and by placing the material closer to the noise source. In this paper we will briefly discuss acoustic liner applications in modern turbofan engines.

• Journal of Electrical Engineering and Technology
• /
• 제12권5호
• /
• pp.1934-1944
• /
• 2017

As a key component of high-voltage power conversion system for electric vehicles (EVs), bidirectional DC/DC (Bi-DC/DC) is required to have high efficiency and light weight. Conventional design methods optimize the Bi-DC/DC at the maximum power dissipation point (MPDP). For EVs application, the work condition of the Bi-DC/DC is not strict as the MPDP, where the design method using MPDP may not be optimal during travel of EVs. This paper optimizes the Bi-DC/DC converter targeting efficiency and weight based on the driving cycle. By analyzing the two-phase interleaved Bi-DC/DC for hybrid energy storage systems (HESS) of EVs, its power dissipation is calculated, and an efficiency model is derived. On this basis, weight models of capacitor, inductor and heat sink are built, as well as a dynamic temperature model of heat sink. Based on these models, a method using New European Driving Cycle (NEDC) for optimal design of Bi-DC/DC which simultaneously considered efficiency and weight is proposed. The simulation result shows that compare with conventional optimization methods revealed that the optimization approach based on driving cycle allowed significant weight reduction while meeting the efficiency requirements.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2002년도 춘계학술대회 논문집
• /
• pp.528-535
• /
• 2002

In order to achieve high precision machine tools, the research for performance enhancement of feed drive systems is required. Development of the high speed feed drive system has been a major issue for the past few decades in machine tool industries. The reduction of the tool change time as well as rapid travel time can enhance the productivity. However, the high speed feed drive system generates more heat in nature, which leads thermal expansion that has adverse effects on the accuracy of machined parts. Stick-slip friction has a great influence on the contouring accuracy of CNC machine tools. In this paper table levitation system has been developed for the stick-slip in a feed drive systems. And also, the driving position is set near the center of the main slideway. From the results, it is confirmed that yaw error and straightness can be improved.

• 기술사
• /
• 제43권6호
• /
• pp.27-30
• /
• 2010

Gyeongbu high-speed railway project which comprises the construction of the new line with 417.5km between Seoul and Busan is one of the biggest national projects with approx. 20-trillion-won project cost. The construction was started in June 1992 and afterward phase I (between Seoul and Daegu) was opened in April 2004 and phase II (between Daegu and Busan, 169.5km) is scheduled for opening in the end of October 2010. It is assured that the opening of the entire sections of Gyeongbu high-speed railway will significantly increase productivity and efficiency by improving the land utilization with the promotion of personal and material exchanges induced by the reduction of travel time between regions. Especially, Gyeongbu high-speed railway will be the opportunity to boost speed-up of Korea railway.

• 한국공작기계학회논문집
• /
• 제11권4호
• /
• pp.102-106
• /
• 2002

Development of high speed feed drive system has been a major issue for the past few decades in machine tool industries. The reduction of the tool change time as well as rapid travel time can enhance the productivity. However, the high speed feed drive system generates more heat in nature, which leads thermal expansion that has adverse effects on the accuracy of machined parts. The detail of the model proposed is described in the paper together with the experimental methodologies using a proposed compact measurement system to examine the validity of the proposed approach. The results showed the machining accuracy could be maintained to better than $\pm$ 5$\mu\textrm{m}$ while using this sensor.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
• /
• pp.309-311
• /
• 2006

A train having a system which tilts the train body to reduce the lateral acceleration experienced by passengers when operating around curves, allowing the train to run at higher speeds through curves than non-tilting trains. A tilting train may have a maximum design service cant deficiency of up to $8^{\circ}$. In this case there is, at worst, a margin of only $6^{\circ}$ cant deficiency between a train travelling at enhanced permissible speed and its roll-over resistance. This is a significant reduction in the margin against overturning compared to that offered at permissible speeds. Particular consideration therefore needs to be given to the adequacy of the margin and the additional controls against overturning required when trains travel at enhanced permissible speeds. This paper deals with the speed supervision system of tilting train through curves.