• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.459-462
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• 2005

The KHST(Korean High Speed Train) which had been developed by through 'G7-R&D project' has succeeded trial running test up to 350km/h on the Kyoung-Bu High Speed Track in December 16th, 2004. In order to evaluate the function and characteristics of KHST, various experimental conditions have been considered and conducted. In this paper, measured current collection characteristics and dynamic behaviors of KHST's pantograph are analysed over 300 to 350km/h in running speed of KHST. A measuring system developed and installed on the KHST for measuring the performance and mechanical characteristics of the KHST's pantograph was used for this trial running test and eventually, we proofed that KHST has a remarkable and stable current collection characteristics as it had been designed.

• 대한조선학회논문집
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• 제48권4호
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• pp.357-362
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• 2011

It has been often reported that a water-jet propelled high speed vessel lost the course keeping ability in seaway. In this study, model tests of a high speed vessel were performed to measure the running attitude and to check the course keeping ability. The model ship may lose the course keeping ability due to bad running attitudes such as bow drop. So model tests were carried out to improve the running attitude by changing the position of longitudinal center of gravity and using appendages at the bow and the stern of a model. The position of lateral center of pressure moved toward stern and the course keeping ability was improved by modifying the transom wedge angle.

• 한국운동역학회지
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• 제28권2호
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• pp.101-108
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• 2018

Objective: The aim of this study was to investigate gender differences in ground reaction force (GRF) components among different speeds of running. Method: Twenty men ($age=22.4{\pm}1.6years$, $mass=73.4{\pm}8.4kg$, $height=176.2{\pm}5.6cm$) and twenty women ($age=20.7{\pm}1.2years$, $mass=55.0{\pm}8.2kg$, $height=163.9{\pm}5.3cm$) participated in this study. All participants were asked to run on an instrumented dual belt treadmill (Bertec, USA) at 8, 12, and 16 km/h for 3 min, after warming up. GRF data were collected from 30 strides while they were running. Hypotheses were tested using one-way ANOVA, and level of significance was set at p-value <.05. Results: The time to passive peaks was significantly earlier in women than in men at three different running speeds (p<.05). Further, the impact loading rates were significantly greater in women than in men at three different running speeds (p<.05). Moreover, the propulsive peak at 8 km/h, which is the slowest running speed, was significantly greater in women than in men (p<.05), and the vertical impulse at 16 km/h, which is the fastest running speed, was significantly greater in men than in women (p<.05). The absolute anteroposterior impulse at 8 km/h was significantly greater in women than in men (p<.05). In addition, as the running speed increased, impact peak, active peak, impact loading rate, breaking peak, propulsive peak, and anteroposterior impulse were significantly increased, but vertical impulse was significantly decreased (p<.05). Conclusion: The impact loading rate is greater in women than in men regardless of different running speeds. Therefore, female runners might be exposed to the risk of potential injuries related to the bone and ligament. Moreover, increased running speeds could lead to higher possibility of running injuries.

• Asian-Australasian Journal of Animal Sciences
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• 제17권2호
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• pp.271-277
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• 2004

The purpose of this experiment was to study the feeding behavior and running speed under various feed deprivation lengths and social environments. Three trials were conducted. Trial 1: ten pigs were trained individually to run a course and eat their feed at the end of the course. The pigs were deprived feed for 1, 5, 10 or 20 h. Trial 2: 1. Two pigs ran and ate together. Both pigs had 5 h of feed deprivation before the run (D5). 2. Two pigs ran and ate alone, but both pigs had 5 h of feed deprivation before the run (S5). 3. Two pigs ran and ate together. Both had 1 h of feed deprivation before the run (D1). 4. Two pigs ran and ate alone and both pigs had 1 h of feed deprivation before the run (S1). 5. Two pigs ran together, one had 5 h of feed deprivation, and the other had 1 h of feed deprivation before the run (51). Trial 3: 1. On the 1st day 5 pairs of pigs had 5 h feed deprivation and could eat feed together at (B) point (D1). 2. On the 2nd day the pigs ran and ate alone at (B) point after 5 h of feed deprivation. Feed was obtainable (D2). On the 3rd to 6th days, the pigs ran in pairs after 5 h of feed deprivation and only the dominant pig ate feed at point (B). The inferior pig was chased back to room and fed there. This stage was continued for four consecutive days, d 3 to 6. In trial 1, the running speed of pigs increased with the length of feed deprivation until 10 h, then being stable afterwards. Total feeding time increased with the length of feed deprivation (p<0.001). Eating speed did not increase with the length of feed deprivation (p>0.05). In trial 2, nine of ten pigs in treatment D5 ran faster than those in S5. Seven of the ten pigs in treatment S1 ran faster than those in treatment D1. The pigs in treatment D5 had significantly higher feed intake (p<0.001) and eating speed (p<0.05) than the pigs in other treatments. In trial 3, there were significant differences on running speed between D1 and D6 (p<0.01) and between D2 and D1, D3, D4 and D5. The inferior pig ran faster in D2 but from 3 to 6 it was the dominant pig that showed the greatest speed in completing the whole course. The results demonstrated that the pigs with low feeding motivation may cause low running speed to feed and low feed intake of the neighbor when compared with pigs kept individually.

• 융합정보논문지
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• 제10권4호
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• pp.160-167
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• 2020

본 연구는 달리기 시 속도와 경사변화가 하지관절의 생체역학적 요인에 미치는 영향을 보고자 한다. 이를 위해 20대 성인남성 15명이 트레드밀에서 2.7, 3.3 m/s와 -9°, -6°, 0°, 6°, 9°로 달리기를 실시하였고, 속도와 경사 변화에 따른 주행특성(보장, 보빈도), 생체역학적 변인(발목, 무릎, 엉덩관절의 가동범위, 모멘트, 관절파워), 지면반력(수직지면반력, 부하율, 제동력, 추진력)을 측정하였다. 연구결과, 주행특성은 오르막 달리기(UR)가 내리막 달리기(DR)에 비해 크게 나타났다(p<.05). 하지관절의 가동범위와 수직지면반력은 UR에서 크게 나타났고(p<.05), 하지관절의 모멘트와 제동력, 추진력, 부하율은 DR에서 크게 나타났다(p<.05). 관절파워는 발목관절은 DR에서 크고, 엉덩관절에서는 UR이 크게 나타났다(p<.05). 이러한 결과로부터 3.3m/s의 속도로 DR을 달리는 경우에서 발목관절 부상의 영향이 클 것으로 예상된다.

• Wind and Structures
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• 제20권2호
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• pp.213-236
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• 2015

For high-speed railways (HSR) in wind prone regions, wind barriers are often installed on bridges to ensure the running safety of trains. This paper analyzes the effect of wind barriers on the running safety of a high-speed train to cross winds when it passes on a bridge. Two simply-supported (S-S) PC bridges in China, one with 32 m box beams and the other with 16 m trough beams, are selected to perform the dynamic analyses. The bridges are modeled by 3-D finite elements and each vehicle in a train by a multi-rigid-body system connected with suspension springs and dashpots. The wind excitations on the train vehicles and the bridges are numerically simulated, using the static tri-component coefficients obtained from a wind tunnel test, taking into account the effects of wind barriers, train speed and the spatial correlation with wind forces on the deck. The whole histories of a train passing over the two bridges under strong cross winds are simulated and compared, considering variations of wind velocities, train speeds and without or with wind barriers. The threshold curves of wind velocity for train running safety on the two bridges are compared, from which the windbreak effect of the wind barrier are evaluated, based on which a beam structure with better performance is recommended.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.399-404
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• 2004

When high speed train runs on heavy curvature section of conventional line, squeal noise emitted from the railroad and wheel. This noise is very unpleasant to the near habitant. In this study, the characteristics and the countermeasures of the squeal noise of high speed train running on the conventional line was investigated.

• 시스템엔지니어링학술지
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• 제15권2호
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• pp.1-8
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• 2019

Autonomous vehicles operated in the rough terrain environment must satisfy various technical requirements in order to improve the speed. Therefore, in order to design and implement a technical architecture that satisfies the requirements for speed improvement of autonomous vehicles, it is necessary to consider the overall technology of hardware and software to be mounted. In this study, the technical architecture of the autonomous vehicle operating in the rough terrain environment is presented. In order to realize high speed driving in pavement driving environment and other environment, it should be designed to improve the fast and accurate recognition performance and collect high quality database. and it should be determined the correct running speed from the running ability analysis and the frictional force estimation on the running road. We also improved synchronization performance by providing precise navigation information(time) to each hardware and software.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1653-1661
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• 2008

A trial run of locally-developed tilting train has been in process on Chungbuk line since the test vehicle was first produced. For the system stabilization, interface verification among the systems including track, structure, catenary and signaling system, not to mention the rolling stock, is very crucial. In the area of wayside structure, the stability of track structure and train run shall be evaluated through the review of impact by increased speed by developed train on track structure. The study thus was intended to evaluate the impact on track while a tilting train is running the conventional line(ballast track), which is vulnerable to accelerated train speed. The evaluation of tilting train test running the part of Honam line was conducted to identify the impact on existing track performance by tilting train. To identify the performance of each part of track components while tilting train and high speed train were running the existing line, wheel load, rail bending stress, vertical displacement of rail and sleeper were compared so as to evaluate the expected impact by tilting train for improving the train speed.

• 한국전산구조공학회논문집
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• 제35권6호
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• pp.375-380
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• 2022

고속철도 교량은 열차 하중에 의한 공진으로 인한 동적응답 증폭의 위험이 존재하므로 설계기준에 따른 동적해석을 통한 주행안전성 및 승차감 검토를 반드시 수행하여야 한다. 그러나 주행안전성 및 승차감 산정 절차는 열차의 종류별로 임계속도를 포함하여 설계속도의 110km/h까지 10km/h 간격으로 동적해석을 일일이 수행해야 하므로 많은 시간과 경비가 소요된다. 이 연구에서는 딥러닝 알고리즘을 활용하여 별도의 동적해석 없이 주행안전성 및 승차감을 사전에 예측할 수 있는 딥러닝 기반 예측 시스템 개발하였다. 제안된 시스템은 철도교량의 열차별, 속도별 동적해석 결과를 학습한 후 학습 완료된 신경망을 기반으로 한 예측 시스템이며, 열차속도, 교량 특성 등의 입력파라미터에 따른 주행안전성 및 승차감 산정 결과를 사전에 예측할 수 있다. 제안된 시스템의 성능을 확인하기 위하여 단경간 직선 단순보 교량을 대상으로 한 주행안전성 및 승차감 예측을 수행하였고, 주행안전성 및 승차감 산정을 위한 상판 연직변위 및 상판 연직가속도를 높은 정확도로 예측할 수 있음을 확인하였다.