• 한국자동차공학회논문집
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• 제9권3호
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• pp.173-180
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• 2001

In the case of axisymmetric thermal analysis of drum brakes, the distribution of frictional heat produced on the interface and temperature difference between mating frictional faces are very interesting problems to computational researchers. In the first part, the influence of the s-cam load angles and elastic modulus of the pad on the contact pressure distribution between pad and drum was checked by a three dimensional model. In the second part heat conduction from the interface to the pad and the drum was modeled by using a thin interface element, so artificial division of the generated frictional heat between pad and drum is not necessary. Temperature difference between mating frictional faces is successfully modeled by using the interface element. The influence of some parameters on the thermal distribution is checked. The analysis was performed by ABAQUS/Standard code.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.88-90
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• 2009

Extremely-Low-Frequency(ELF) magnetic fields are generated around power cables and bus bars in power systems. Such the stray fields may cause disturbances to nearby electronic apparatus and affect even human health. In order to seeking out a proper way to reducing the fields, the first thing to do is to accurately predict field distribution around analysis models of interest. Then, optimization techniques should be applied for finding a more improved design than the initial one. To achieve this goal, commercial electromagnetic software, MagNet, is combined with evolution strategy algorithm. For verification of the proposed method, three-phase power line cables and busbar systems have been tested.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.92-99
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• 2013

High oil price and global warming problem are being continued all over the world. For this reason, fuel economy and emission of greenhouse gas are regulated by law in many countries. Therefore many companies are researching and producing hybrid electric vehicles (HEVs) which substitute conventional internal combustion engine vehicle. However, these researches and productions are restricted to mainly passenger cars. Because of cost and physical problems, commercial vehicles are difficult to evaluate fuel economy. So simulations are important and it is necessary to know how sensitive parameters that enter into simulation affect. In this paper, forward simulations using AVL Cruise were conducted for analysis of fuel economy for parallel hybrid bus and were repeated by changing each parameter. Based on these results, root mean square errors (RMSE) are calculated for analysis of fuel economy sensitivity. The number of target parameters are 15. These parameters were classified with high and low sensitivity parameter relatively.

• 한국도로학회논문집
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• 제20권2호
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• pp.75-85
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• 2018

PURPOSES : This study aimed to analyze traffic accidents at circular intersections, and discuss accident reduction strategies based on land use and vehicle type. METHODS : Traffic accident data from 2010 to 2014 were collected from the "traffic accident analysis system" (TAAS) data set of the Road Traffic Authority. To develop the accident rate model, a multiple linear regression model was used. Explanatory variables such as geometry and traffic volume were used to develop the models. RESULTS : The main results of the study are as follows. First, it was found that the null hypotheses that land use and vehicle type do not affect the accident rate should be rejected. Second, 16 accident rate models, which are statistically significant (with high $R^2$ values), were developed. Finally, the area of the central island, number of speed humps, entry lane width, circulatory roadway width, bus stops, and pedestrian crossings were analyzed to determine their effect on accidents according to the type of land use and vehicle. CONCLUSIONS : Through the developed accident rate models, it was revealed that the accident factors at circular intersections changed depending on land use and vehicle type. Thus, selecting the appropriate location of bus stops for trucks, widening entry lanes for cars, and installing splitter islands and optimal lighting for motorcycles were determined to be important for reducing the accident rate. Additionally, the evaluation showed that commercial and mixed land use had a weaker effect on accidents than residential land use.

• 한국ITS학회 논문지
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• 제16권2호
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• pp.161-170
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• 2017

발리스는 열차의 안전한 운행을 위하여 철도의 레일 사이에 설치하여 운영하는 장치로, 텔레그램이라 칭하는 정보(거리 구배 속도 임시 속도제한 등의 가변정보)를 무선으로 통과하는 열차에 전송하는 기능을 갖는다. 본 연구는 이에 필요한 DBPL 인코더의 설계에 대한 것이다. 일반적으로 발리스를 위한 DBPL 인코더는 전용 ASIC이나 FPGA를 통하여 구현하고 있으나, 본 연구에서는 범용의 저전력 마이크로컨트롤러(STM32L4 Series)를 활용하여 설계하였다. 본 연구의 DBPL인코더는 펌웨어 방식의 논리적 1차 처리 수단과 마이크로컨트롤러 내장 SPI Bus 등을 이용한 물리적 출력수단으로 구분하여 설계하였다. 본 연구의 DBPL 인코더는 유로발리스 표준에서 요구하는 564.48Kbps의 속도로 동작 가능함을 확인하였다.

• 한국농촌건축학회논문집
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• 제17권1호
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• pp.73-81
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• 2015

The purpose of this study is to analyze the approach characteristics, relation to other facilities, and current status focusing on 28 total of exhibition-culture facilities in Gangneung. The results are following as. First, 19 facilities are located in urban area and nine are located in country side. With locational characteristics of Gangneung which is mountains in west and sea to east, three are located in high hill side and four are in sea shore among nine facilities. Facilities in urban area converge to Gungpodae and Ojukhuk which are symbol space in Gangneung. Those facilities started to have been increased from 1990s and rapidly increased from 2000s. The reason is that people have been interested in culture and art in society in general. In building structure, buildings related with traditional contents were constructed with wooden structure while buildings have been mainly constructed with modern ways such as steel and reinforced concrete structure. Second, the 28 facilities are classified into three types by function of other space or facilities within same a site or a building. The three types are themselves usage only, multi-function, and park type. The multi-function type is re-classified into two; public type and commercial type. Those functions have changed according to changes of society and times. Finally, for approaching to the exhibition-culture facilities with general transportation, the mean distance from the closest bus stop to those facilities each is 280m and 27 facilities are located within 670m from the closest bus stop. For approaching way using by car creates movement along road-building site-parking space-main entrance of building. When based on main entrance by the movement, parking space located in front side of main entrance is the largest, next is in the side, and the least is in back side. Various factors such as approaching form from road to parking space and space size between main entrance and parking space influence to approaching ways of exhibition-culture facilities in Gangneung.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.72-82
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• 2005

The objective of this paper is to describe the optimization of design parameters in a large-sized commercial bus heater system by using CFD(computational fluid dynamics) analysis and Taguchi method. In order to obtain the best combination of each control factor which results in a desired performance of heater system, the parameter design of the Taguchi method is adopted for the robust design considering the dynamic characteristic. The research activity may be divided into four phases. The first one is analyzing the problem, i.e., ascertaining the influential factors. In the second phase the levels were set in such a way that their variation would significantly influence the response. In the third phase the experimental runs were designed. In the final phase the planned runs were carried out numerically to evaluate the optimal combination of factors which is able to provide the best response. In this study, eight factors were considered for the analysis: one with two level and seven with three level combinations comprising the $L_{18}(2^1{\times}3^7)$ orthogonal array. The results of this study can be summarized as follows ; (i)The optimum condition of control factor is a set of <$A_2\;B_1\;C_3\;D_3\;E_1\;F_2\;G_3\;H_2$> where A is shape of the outer fin, B is pitch of the outer fin, C is height of the outer fin, D is the inner fin number, E is the inner fin height, F is length of the flame guide, G is diameter of the heating element and H is clearance between air guide and heating element. (ii)The heat capacity of heated discharge air under the optimum condition satisfies the equation y=0.6M w here M is a signal factor. (iii)The warm-up rate improves about three times, more largely as com pared with the current condition, which results in about 9.2minutes reduction.

• 한국ITS학회 논문지
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• 제16권6호
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• pp.16-28
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• 2017

본 연구에서는 운수종사자시스템과 운행기록분석시스템을 활용하여 시내버스 고령운전자 운전적성정밀검사의 신규검사결과, 사고 및 벌점현황, 운행기록자료를 분석하였다. 분석결과 시내버스 고령운전자를 사고수가 많은 관심대상 운수회사와 관리가 잘 되고 있는 교통안전 우수회사와 비교했을 경우 운전적성정밀검사의 결과는 비슷하였으나 최근 5년 동안 운행하면서 발생한 총 벌점은 상당한 차이를 보였고 사고의 경우 평균 중상자수와 경상자의 수도 적은 것으로 확인됐다. 또한 운행 100km당 위험운전행동 횟수를 비교해보면 우수회사의 고령운전자는 다른 고령운전자와 비고령운전자와 비교해서도 위험운전행동 횟수가 상당히 적은데 잘못된 운전습관의 교정결과에 따른 것으로 나타났다.

• 한국정밀공학회지
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• 제28권12호
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• pp.1434-1440
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• 2011

In this paper, we assessed muscular activities of lower limbs and foot pressure for car and bus drivers according to operating three electronic pedals that we developed. To analyze drivers' physical exhaustion, muscular fatigue of lower limbs was evaluated. Eleven car drivers and six urban bus drivers were participated in this experiment. The virtual driving system was used for the real driving environment. The virtual driving system was comprised of a spring seat, a steering wheel, pedals (clutch, excel and brake pedals), a manual transmission and a virtual driving simulation. For the real vibration like situation on the road, six degree of freedom motion base system was used. Measured muscles were rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA) and gastrocnemius (Gn) muscles. For the quantitative muscular activities, integrated electromyography (IEMG) was analyzed. Muscular fatigues also were analyzed through the analysis of the median frequency. In addition, foot pressures were analyzed and compared through the peak and averaged pressure during the operating three developed electronic pedals. The experiments are conducted with total 17 drivers, 11 general public and 6 drivers. As a result of the analysis, electromyogram and fatigue analysis through intermediate frequency reduction for pedal-1 more efficient than other pedals. And foot pressure also was decreased. Consequently, we suggested the most efficient pedal and method to minimize the amount of cumulative fatigue.

• 한국정보과학회논문지:시스템및이론
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• 제27권2호
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• pp.177-187
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• 2000

최근 몇 년간 클리스터링 기반 다중 프로세서 시스템에서의 상호 연결망으로서의 버스의 제약을 극복하기 위한 단방향 지점간 링크를 이용한 링 구조가 제안되었다. 하지만 계속되는 프로세서의 고속화와 지역 버스 및 메모리의 고성능화로 인해 지점간 링크의 현재 표준 대역폭으로는 시스템 확장성에 한계를 보이며 이에 따라 대역폭 확장에 대한 연구가 필요하다. 본 논문에서는 클리스터링 기반 다중프로세서 시스템으로 개발된 PANDA 시스템을 기본 모델로 채택한다. 최근 대중화된 프로세서 및 지역 버스의 사양을 반영한 모의실험을 통해 현재의 지점간 링크가 전체 시스템 성능에 병목이 됨을 보여주고 두 배 이상의 대역폭 확장이 필요함을 보인다. 상호 연결망의 대역폭을 확장하기 위해, 두 배 증가된 대역폭을 지닌 새로운 링크를 개발하는 것은 과다한 설계비용과 개발시간이 요구된다. 이에 대한 대안으로 본 논문에서는 상용화되어있어 쉽게 적용 가능한 기존 IEEE 표준 대역폭을 가진 링크를 이용해 이중으로 링을 구성하는 몇 가지 방법 단순 이중 링, 트랜잭션 분리 이중 링, 방향 분리 이중 링 - 을 제시하고 모의실험을 통해 두 배 대역폭 단일 링과 더불어 각각의 방식에 대한 장단점을 분석한다.