• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.54-66
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• 2018

In this study, vehicle speeds at acceleration and deceleration lanes of rest areas for drowsy drivers were investigated to analyze effects of acceleration and deceleration lane lengths, grades and curve radius. In addition, we used VISSM to analyze proper lengths of rest area's acceleration and deceleration lanes. Several VISSIM scenarios with different lengths of acceleration and deceleration lane were constructed. Through VISSIM simulation, we collected individual vehicle speed data to analyze speed changes by different lengths of acceleration and deceleration lanes. As a result of the vehicle speed change investigation, grades and curve radii of the rest area affected the speed, most of all lengths of acceleration and deceleration lane showed a great effect on the vehicle speed. In the case of short lengths of acceleration and deceleration lane, speed variation among vehicles was significant. If the deceleration lane length is short, the vehicle enters a state in which the speed is not sufficiently reduced, and if the acceleration lane length is short, the vehicle enters a state in which the speed is not sufficiently accelerated showing high risks of conflicts and accidents. It is recommended that 245m length of deceleration lane and 370m length of acceleration lane should be installed at least to secure safety and manage conflicts relevantly.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1359-1366
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• 2010

Recently, many electronic control techniques for vehicles have been developed and applied. One of the technologies can be X-by-wire such as throttle-by-wire, brake-by-wire, steer-by-wire, and etc, in which most of mechanical parts are replaced into electrical wire and actuators. In this study, the effect of throttle-by-wire and brake-by-wire control systems on vehicle velocity control, especially in a school zone, are taken into consideration. The number of accidents reported in school zones is higher than that in other places. The reason for this is that many vehicle drivers do not obey speed limit regulations. Moreover, some of the students are careless while crossing the streets. Therefore, in this study, we attempt to develop a method using throttle-by-wire and brake-by-wire control systems for automatically reducing the vehicle speed such that it will be within the speed limit. First, an engine model and a transmission system model are developed for a specific vehicle model. Second, speed reduction is carried out such that the reduction follows a pre-designed cubic spline trajectory; the trajectory is determined such that rapid deceleration, which causes discomfort to the driver and passengers, can be prevented, for which a fuzzy-PID control algorithm is applied for the trajectory following control. Finally, simulation results are presented to verify the performance of the proposed speed reduction control system.

• Korean Journal of Veterinary Research
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• v.21 no.2
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• pp.123-133
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• 1981

진드기는 생물학적(生物學的) 여러 분야(分野)의 연구대상(硏究對象)으로 또는 진드기 매개전염병(媒介傳染病)의 역학(疫學)과 방제(防除)를 위(爲)한 연구재료(硏究材料)로 공시(供試)되는데, 이를 위(爲)하여는 실험작군(實驗作群)에 의(依)한 집단생산(集團生産)이 요구(要求)된다. 그러나 이러한 실험작군(實驗作群)에 있어서 동일(同一)한 가토(家兎)를 실험용(實驗用) 숙주(宿主)로 반복(反復)하여 사용(使用)했을 경우(境遇), 진드기의 흡혈성취도(吸血成就度)가 저하(低下)되는 현상(現象)을 경험(經驗)하게 된다. 이러한 현상(現象)에 흥미(興味)를 가지고, 이를 실험용(實驗用) 가토(家兎)에 대(對)한 Haemaphysalis longicornis 미포혈(未飽血) 자충(雌蟲)의 반복흡혈(反復吸血)에 있어서의 흡혈성취도(吸血成就度) 변화(變化)를 조사(調査)해 보고자 몇가지 실험(實驗)이 설계(設計) 진행(遂行)된 바, 결과(結果)는 다음과 같이 요약(要約)된다. 1. 최초(最初)(1차(一次)) 흡혈시도(吸血試圖)에 있어서 공시(供試)된 진드기의 흡혈성취도(吸血成就度)는 실험용(實驗用) 숙주(宿主)인 가토(家兎)의 월령별(月齡別) 비교군간(比較群間)에 유의성(有意性) 있는 차이(差異)가 인정(認定)되지 아니 하였다. 2. 성공적(成功的) 흡혈율(吸血率)은 최초(最初)(1차(一次)) 흡혈시도(吸血試圖)에서 82.29%를 보였으나, 반복흡혈시도(反復吸血試圖) 차수(次數)가 증가(增加)함에 따라, 76.04%(2차(二次)), 53.13%(3차(三次)), 50%(4차(四次)), 46.87%(5차(五次))로 점차적(漸次的)으로 저하(低下)되는 성적(成績)을 보였다. 3. 평균흡혈기간(平均吸血期間)은 최초(最初)(1차(一次))흡혈시도(吸血試圖)에서 9.34일(日)을 보였으나, 반복흡혈시도(反復吸血試圖) 차수(次數)가 증가(增加)함에 따라, 9.74일(日)(2차(二次)), 10.31(日)(3차(三次)), 10.42(日)(4차(四次)), 10.47(日)(5차(五次))로 점차(漸次) 지연(遲延) 되었으며, 평균흡혈속도(平均吸血速度)는 0.1070에서 0.1027, 0.0970, 0.0960, 0.0955로 점차(漸次) 감속화(減速化) 되었다. 4. 평균(平均) 흡혈체중(吸血體重)에 있어서는 최초(最初)(1차(一次)) 흡혈시도(吸血試圖)에서 253.3mg의 성적(成績)을 보였으나, 흡혈시도(吸血試圖)가 반복(反復)됨에 따라, 242.58mg(2차(二次)), 190.73mg(3차(三次)), 187.85mg(4차(四次)), 184.18mg(5차(五次))으로 점차(漸次) 경량화(輕量化)되는 경향(傾向)을 나타냈다. 5. 결론적(結論的)으로 실험용(實驗用) 가토(家兎)에 대(對)한 Haemaphysalis longicornis 진드기의 흡혈성취도(吸血成就度)는, 반복흡혈시도(反復吸血試圖) 차수(次數)가 증가(增加)함에 따라, 숙주체내(宿主體內)에 형성(形成) 누적(累積)되는 진드기에 대(對)한 획득면역(獲得免疫)의 영향(影響)을 받아 점차(漸次) 저하(低下)되며, 따라서 H. longicornis 진드기의 집단생산(集團生産)을 위(爲)한 실험작군(實驗作群)이나 혈류보존(血統保存)을 위(爲)한 계대흡혈(繼代吸血)에 있어서 동일(同一) 가토(家兎)를 2회이상(回以上) 반복사용(反復使用)하는 것은 바람직한 일이 아닌 것으로 사료(思料)된다.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.145-157
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• 2004

Microscopic freeway simulation models project the uncertain values of performance measures for subject traffic conditions by explaining drivers' driving behavior with lane changing and car-following models. However, the existing lane changing models are limited to gap acceptance oriented passive behavior of drivers and not able to capture more-or-less aggressive driving behavior(e.g. cut-in lane changing) ordinarily obseved in field. This paper suggests the definition of cut-inlane changing and presents its characteristics based on the findings from two different freeway on- and off-ramp sections. In addition, this paper proposes a new lane changing model capable of handling both passive and active drivers' driving behavior for better performance of simulations. The proposed lane changing model was tested with Hanyang Simulatin (HYTSIM), a microscopic freeway simulation program developed for this study. The HYTSIM simulation results reflecting the performance of the proposed lane changing model were compared against the field data. The test results showed that the distribution of gaps collected when vehicles change lanes were statistically identical to the field data at 95% confidence level.

• Journal of the Korean Association of Geographic Information Studies
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• v.4 no.3
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• pp.51-60
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• 2001

The travel behavior can be analysed microscopically using GPS because the travel characteristics can be found out by travelling two test cars loaded with GPS equipments. The speed difference and spacing variation between the lead vehicle and the following's in uninterrupted flow are the important variables related to capacity and safety. This study analysed these with data obtained by travelling the 4th Line and 28th Line of the national road. The variation width in speed difference in the run time is below 3.0%. But, related to the speed difference in the situation of acceleration and deceleration the difference after 4second is bigger than that just after the start. The spacing variation is similar to this. The spacing just before deceleration concerning safety was analysed. When the theoretical values by the modeling method and observed values were compared, the observed values were analysed 12.52% shorter than the other in average.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.5
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• pp.445-454
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• 2020

Non-breakaway crashworthy sliding posts move rigidly with a vehicle in the early stage of vehicle impact. During this stage, a vehicle imparts its linear momentum to the post, experiencing first-stage speed loss followed by second-stage loss from the crush of the energy-absorbing pipe (EAP) installed under the guide rail. An EAP is the key element of a crashworthy sliding post and should be confined to the post foundation. This paper covers the development of an EAP for a sliding post of 507 kg, which is a sliding post type frequently used in Korea for cantilever signs. Detailed explanations of the designs for an EAP structure using LS-DYNA impact simulation are given, and the crashworthiness of the systems are confirmed through crash tests. The EAP presented in this paper can accommodate impacts from 0.9 ton-60 km/h to 1.3 ton-80 km/h, and is applicable to foundations up to 2.7 m in length.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.140-141
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• 2014

본 논문에서는 DC배전 전기추진 선박에서 전력품질 향상 및 전력 공급 안정성을 위한 리튬-이온 배터리 에너지 저장장치(BESS)를 적용하고 이에 대하여 기술한다. MATLAB/Simulink를 이용하여 DC배전 전기추진 선박 및 리튬-이온 배터리 에너지 저장장치의 시뮬레이션 모델을 구현하였으며, 구현된 시뮬레이션 모델에 발전 전력과 소비 전력 간의 전력 수급 차로 DC 계통의 전압 변동이 발생되는 추진전동기의 급격한 가, 감속 운전 시나리오를 적용하였다. 적용 시나리오에 의해 발생된 전압 맥동 현상은 리튬-이온 배터리 에너지 저장장치를 이용하여 IEEE STD. 1709 - 2010에서 제시하는 전압 허용 범위를 만족함으로써 DC배전을 갖는 전기추진 선박의 전력품질 향상 및 전력 공급의 안정성 여부를 검토한다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.1
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• pp.23-28
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• 2011

This paper outlines extraction potential of tidal stream resources from the simplified channel in which flow is driven by a head difference between inlet and outlet. Energy extraction alters the flow within a simple channel, and extraction of 10% energy flux in a natural channel would give rise to a flow speed reduction of about 5.7%. If 20% of the undisturbed energy flux is extracted, the flow speed is reduced by 11.3%. The simple channel also suggests that extractable energy might be higher if flow speed reductions are considered acceptable.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.170-177
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• 2020

This study examined the clamping force control method and the braking performance test results of an electromechanical brake (EMB) using braking test equipment. Most of the studies related to EMBs have been carried out in the automotive field, dealing mainly with the static test results for various control methods. On the other hand, this study performed a dynamic performance evaluation. The three-phase interior permanent magnet synchronous motor (IPMSM) was applied to drive the actuator of the EMB, and the analysis was verified by JMAG(Ver. 18.0), which is finite element method (FEM) software. The current control, speed control, and position control were used for clamping force control of the EMB, and the maximum torque per ampere (MTPA) control was applied to the current controller for efficient control. The EMB's emergency braking deceleration performance was tested in the same way as conventional pneumatic brake systems when the wheel of a train rotates at 110 km/h, 230 km/h, and 300 km/h. The emergency braking time, with the wheel stopped completely at the maximum rotational speed, was approximately 73 seconds. The similarity of the braking time and deceleration pattern was verified through a comparison with the performance test results of the pneumatic brake system applied to the next generation high-speed railway vehicle (HEMU-430X).

• Journal of Life Science
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• v.19 no.9
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• pp.1299-1303
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• 2009

The purpose of this study was to analyse the gait characteristics of stroke patients walking on a Zebris system, through quantitative three-dimensional biomechanical analysis. They underwent a continuous rehabilitation training program (RTP). A comparison was made between 3 month and 6 month RTP participants. Their ages were between 60 and 65. The data were analyzed by t-test. The result of comparative analysis of the two groups can be summarized as below. Temporal-spatial data, sagittal plane angular kinematics data, and peak ground reaction force and max pressure data showed that there were no significant differences between the 3 month RTP group and the 6month RTP group (Table 2, Table3, Table 4). It can be suggested that patients with hemiplegia after stroke can improve their walking function through continuous RTP participation.