• Title/Summary/Keyword: Small car

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Simulation Analysis on the Impact of Racing Car with Space Frame (스페이스 프레임을 가진 경주용 차량의 충돌에 관한 시뮬레이션 해석)

  • Cho, Jae-Ung;Bang, Seung-Ok;Kim, Key-Sun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.7
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    • pp.2341-2348
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    • 2010
  • In this paper, strain and stress on space frame are analyzed at racing car under crash loads. As the deformation is reduced to a minimum during crash and the vulnerable parts are grasped, the safety of driver is ensured. The vehicle frame is modelled with truss structure by inputting the material property of carbon steel on finite element analysis. The increase of impulse momentum is due to speed change at frontal collision. This influence effected on vehicle frame is also analyzed by ANSYS program. The deformation of the frame is studied by applying the crash loads at front, side and rear directions. Though the influence on the seat of driver is small at frontal and rear crash, the deformation due to impact is progressed into this seat. The safety of frame is enhanced by making up for these weak deformations and these results of simulation analysis can be applied to the production of the actual vehicle frame.

Static and Dynamic Stability Evaluation of Model Guardrail Posts Based on Geotechnical Properties (지반특성에 기초한 모형 연성방호책 지주의 정적 및 동적안정성 평가)

  • Lim, Yu-Jin
    • International Journal of Highway Engineering
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    • v.11 no.1
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    • pp.233-245
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    • 2009
  • Availability of pressuremeter test for evaluation of geotechnical properties of foundation soil into which guardrail post is to be installed is investigated in this study. First, an analysis method of the post based on the pressuremeter test is proposed that can obtain bending moment and load-deformation profiles of the post. Then static horizontal load test onto a small scale guardrail post is performed in order to get bearing capacity and load-deformation pattern of the model post. The obtained results are compared with the load-deformation curves and bearing capacity of the post obtained from the pressuremeter method. In addition horizontal impact test to the post is performed using a model bogie car in order to check failure pattern around the model foundation and to investigate dynamic bearing capacity due to deceleration and inertia force of the soil. It is verified that the pressuremeter test is so useful and reasonal technique to analyze road foundation-post interaction.

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Study of the Air-tightness Requirement Decisions of GTX Trains (GTX 차량기밀도 요구성능 도출에 관한 연구)

  • Yun, Su-hwan;Cho, Yong-hyeon;Hong, Seok-woo
    • Journal of the Korean Society for Railway
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    • v.18 no.6
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    • pp.513-521
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    • 2015
  • When a GTX travels through a deep-level underground tunnel at a speed of 180km/h, ear-discomfort in passengers due to the pressure wave generated could be an issue due to the small cross-sectional area. Therefore, appropriate pressure-tightness values for GTX trains must be secured as a countermeasure. In this paper, a 1D numerical analysis was conducted to determine the pressure-tightness coefficient which allows a pressure change meet the criteria. The pressure transients in a tunnel and in a passenger car are predicted considering an A-line underground tunnel with a length of 37km and its operation schedule. The required pressure-tightness of the car is predicted to be three seconds and 6 seconds respectively for a single track and a double- track tunnel to prevent aural discomfort in passengers. The result of this study are expected to serve as useful information to those involved in the development of various solutions to improve air-tightness of GTX passenger cars.

A Strategy of Technology Transfer Based on M&A in Small & Venture Business (중소·벤처기업의 M&A를 이용한 기술이전 전략)

  • Song, Myung Kyu;Jeong, Hyesoon;Lim, Dae-Hyeon
    • Knowledge Management Research
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    • v.5 no.1
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    • pp.39-56
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    • 2004
  • Mergers and Acquisitions(M&A) have long played an important role in the growth of firm. M&A has been considered a effective strategy for Korean government to restructure industry. Previous studies provided mixed results on the synergy effect of M&A This study provides investigation on 39 mergers occurred over the sample period from 2000 to 2001. In this study, event study methodology arc used to calculate abnormal return(AR) and cumulative abnormal return(CAR) based on mean-adjusted model. The testing period of this study from date -30 through date +30, where date zero is the date of the first public announcement of the merger. The empirical results in this study can be summarized as follows. First, the return rates of KOSDAQ registered firms with M&A appears higher than that of KSE listed firms. This means that public announcement of M&A is more influential on stock price for KOSDAQ registered firms than KSE listed firms. Second, The difference between actual merging price and fair value is significant in KSE listed firms and KOSDAQ registered firms. This means that the investors take M&A of KOSDAQ registered firms as a good news. Third, the impact on the market prices of merging firms take place after the first public announcement of the merger in KSE registered firms. But the impact on the market prices take place not only merging firms but also merged firms in KOSDAQ registered firms. This result shows that the investors recognize a M&A is a strategy of technology transfer in small & venture business.

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A study on the derivation of Dimensionless Unit Hydrographs by the Linear model in the small watersheds (선형 Model에 의한 소류역에 있어서의 무차원 단위도 유도에 관한 연구)

  • 이순혁;한중석
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.23 no.3
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    • pp.78-87
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    • 1981
  • This study was attempted to get dimensionless unit hydrograph by linear model which can be used to the estimation of flood for the development of Agricultural water resources and laid emphasis on the application of dimensionless unit hydrographs for the ungaged watersheds by applying linear model. The results summarized through this study are as follows. 1.Peak discharge is found to be Qp= CAR (C =0. 895A-o.145) having high significance between peak discharge, Qp and effective rainfall, R within the range of small watershed area, 84 to 470km2. consequently, linearity was acknowledged between rainfall and runoff. Reasonability is confirmed for the derivation of dimensionless unit hydrograph by linear model. 2.Through mathematical analysis, formula for the derivation of dimensionless unit hydrograph was derived. qp--p=(tp--t)n-1[e-(n-1)](tp--t-1) 3.Moment method was used for the evaluation of storage constant, K and shape parameter, n for the derivation of dimensionless unit hydrograph. Storage constant, K is more closely related with the such watershed characteristics as length of main stream and slopes. On the other hand, the shape parameter, n was derived with such watershed characteristics as watershed area, river length, centroid distance of the basin and slopes. 4.Time to peak discharge, Tp could be expressed as Tp=1. 25 (√s/L)0.76 having a high significance. 5.Dimensionless unit hydrographs by linear model stood more closely to the observe dimensionless unit hydrographs On the contrary, dimensionless unit hydrographs by S.C. S. method has much difference in comparison with linear model at the falling limb of hydrographs. 6.Relative errors in the q/qp at the point of 0.8 and 1.2 for the dimensionles ratio by linear model and S. C. S. method showed to be 2.41, 1.57 and 4.0, 3.19 percent respectively to the q/qp of observed dimensionless unit hydrographs. 7.Derivation of dimensionless unit hydrograph by linear model can be accomplished by linking the two empirical formulars for storage constant, K, and shape parameter, n with derivation formular for dimensionless unit hydrograph for the ungaged small watersheds.

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Vehicle Detection in Aerial Images Based on Hyper Feature Map in Deep Convolutional Network

  • Shen, Jiaquan;Liu, Ningzhong;Sun, Han;Tao, Xiaoli;Li, Qiangyi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.4
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    • pp.1989-2011
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    • 2019
  • Vehicle detection based on aerial images is an interesting and challenging research topic. Most of the traditional vehicle detection methods are based on the sliding window search algorithm, but these methods are not sufficient for the extraction of object features, and accompanied with heavy computational costs. Recent studies have shown that convolutional neural network algorithm has made a significant progress in computer vision, especially Faster R-CNN. However, this algorithm mainly detects objects in natural scenes, it is not suitable for detecting small object in aerial view. In this paper, an accurate and effective vehicle detection algorithm based on Faster R-CNN is proposed. Our method fuse a hyperactive feature map network with Eltwise model and Concat model, which is more conducive to the extraction of small object features. Moreover, setting suitable anchor boxes based on the size of the object is used in our model, which also effectively improves the performance of the detection. We evaluate the detection performance of our method on the Munich dataset and our collected dataset, with improvements in accuracy and effectivity compared with other methods. Our model achieves 82.2% in recall rate and 90.2% accuracy rate on Munich dataset, which has increased by 2.5 and 1.3 percentage points respectively over the state-of-the-art methods.

Impact Condition of Safety Performance Evaluation for Longitudinal Barriers of SMART Highway (스마트하이웨이 종방향 방호울타리안전성능 평가를 위한 충돌조건)

  • Kim, Dong-Seong;Kim, Kee-Dong;Ko, Man-Gi;Kim, Kwang-Ju
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.3
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    • pp.49-57
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    • 2009
  • To minimze the degree of damage for the SMART highway's punctuality and safety after car-barrier collisions, the impact condition for longitudinal barriers of SMART highway was determined to be quite larger than the existing maximum impact condition. The impact condition consists of impact vehicles, impact velocities, and impact angles. To consider the occupant safety of passenger cars as much as possible, a small car with high risk during impact was selected as the impact vehicle for the evaluation of occupant risk. The impact velocity was determined to be 20% larger than the existing maximum impact velocity in order to include accident impact velocities as much as possible. The impact angle was determined to include most of expected accident impact angles. Computer simulations using various impact conditions were conducted for the existing domestic highest-performance medium and roadside barrier. How the suggested impact condition has an effect on the occupant safety was investigated. The existing domestic highest-performance medium and roadside barriers could not satisfy the suggested impact condition. New high-performance longitudinal barriers are required to minimize the degree of damage for the SMART highway's punctuality and safety after car-barrier collisions.

Pattern Analysis for Urban Spatial Distribution of Traffic Accidents in Jinju (진주시 교통사고의 도시공간분포패턴 분석)

  • Sung, Byeong Jun;Yoo, Hwan Hee
    • Journal of Korean Society for Geospatial Information Science
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    • v.22 no.3
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    • pp.99-105
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    • 2014
  • Since traffic accidents account for the highest proportion of the artificial disasters which occur in urban areas along with fire, more scientific an analysis on the causes of traffic accidents and various prevention measures against traffic accidents are needed. In this study, the research selected Jinju-si, which belongs to local small and medium-sized cities as a research target to analyze the characteristics of temporal and spacial distribution of traffic accidents by associating the data of traffic accidents, occurred in 2013 with the causes of traffic accidents and location information that includes occurrence time and seasonal features. It subsequently examines the spatial correlation between traffic accidents and the characteristics of urban space development according to the plans of land using. As a result, the characteristics of accident distribution according to the types of accidents reveal that side right-angle collisions (car versus car) and pedestrian-crossing accident (car versus man) showed the highest clustering in the density analysis and average nearest neighbor analysis. In particular, traffic accidents occurred the most on roads which connect urban central commercial areas, high-density residential areas, and industrial areas. In addition, human damage in damage conditions, clear day in weather condition, dry condition in the road condition, and three-way intersection in the road way showed the highest clustering.

A Relative Importance Analysis of Promoting Factors for Technological Commercialization of Small and Medium Enterprises Manufacturing Railway Car Parts (철도차량부품 제조 중소기업의 기술사업화 촉진요인에 대한 상대적 중요도 분석)

  • Kim, Myung Jong;Koo, Jeong Seo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.38 no.6
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    • pp.1001-1012
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    • 2018
  • Regarding the small- and medium-sized enterprises in Korea that manufacture the railway vehicle parts, there are over 250 related companies. And they have been surviving in the form of producing and delivering the parts of the railway vehicles by importing the technologies and the products of the foreign countries rather than possessing their own technological abilities. Due to this, regarding the industry of the core components of the railroads, the dependence on the overseas has been high. As such, although, for supporting the small- and medium-sized enterprises that manufacture the railway vehicle parts, the government has been strengthening the diverse policy supports, it is a fact that the effectiveness of the support is not high. And, in order to effectively support these, there is a need to understand clearly and definitely what the important promotion factors are in the process of the technology commercialization. Accordingly, through the precedent researches regarding the factors that promote the technology commercializations of the small- and medium-sized enterprises that manufacture the railway vehicle parts, this research had extracted 10 main items. And the level of the importance of these indices was analyzed by using the AHP (Analytic Hierarchy Process). As a result of the AHP analysis, the factors within a corporation appeared to be the most important factor. And, as for the lower-ranking item, the commercialization capability was analyzed to be the most important item. It is highly expected that the contents and the results of this research will be usefully used when formulating the planning of the support program and the support policy for the technology commercializations by the public research organizations and the railroad management organization, which is an organization that supports the small- and medium-sized enterprises that manufacture the railway vehicle parts.

A Study on Cognition about 119 Rescue·First Aid Team - Gwangju Area College Student as the Central Figure - (119구조·구급대에 대한 인식도 조사 연구 - 광주지역 보건계열과 비보건계열 대학생을 중심으로 -)

  • Kim, Kab-Sun
    • The Korean Journal of Emergency Medical Services
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    • v.6 no.1
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    • pp.141-152
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    • 2002
  • The purpose of this study is to provide the basic materials for searching the way of improvement to heighten the emergency medical welfare level by one step further. To achieve this purpose, the subjects of this study were selected 452 college students in Gwangju, using a random sampling method. The statistical analysis methods utilized for analyzing the collected data are frequency analysis, $x^2$ test. The conclusions obtained from these analyses are as following ; 1. In question about necessary optimum number of persons for rescue first aid activity, health and non-health major college students responded by 39.2%, 45.3% respectively that rescue team 15 people, first aid team 3 people is most suitable. But there was no significant difference in major department(p<0.05). 2. In question about security of the public health doctor and the emergency medical technician, all health and non-health major college students are recognizing necessity urgently, but there was no significant difference in major department(p<0.05). 3. In question about 119 rescue first aid team member applying for an examination qualification grant to the department of EMT's graduate, all health and non-health major college students were highest by 52.9%, 52.4% respectively in "necessity" item. But there was no significant difference in major department(p<0.05). 4. Because rescue first aid equipment level appears higher than 41.7% in non-health major college student's case by 54.2% in health major college student's case, health major college students are recognizing that equipment level should be supplemented more but there was no significant difference in major department(p<0.05). 5. In question about equipment supplement, all health and non-health major college students appeared highest by 64.8%, 69.3% in accident type different special equipment. But there was no significant difference in major department(p<0.05). 6. In question about rescue ambulance car size, we could know being thinking that health and non-health major college student each 61.2%, 56.5% is small and narrow that large size of the rescue ambulance amount need. But there was no significant difference in major department(p<0.05). 7. In question about patient's state is worsened, because rescue first aid equipment is inferior, health major college student responded sometimes 55.1%, many 29.5%. very many by 11.5%, while non-health major college student responded 65.8%, 23.1%, 4.0% respectively. There was significant difference in major department(p<0.05). 8. In question about emergency patient must utilize for 119 rescue ambulance car, all health and non-health major college students appeared highest by 38.8%, 41.3% in "not so" item. In question about rescue first aid team's first-aid treatment ability improves more, all health and non-health major college students appeared highest by 58.1% and 58.7% respectively in "improve" item. In question about "119 rescue ambulance car must go more rapidly than now", all health and non-health major college students are recognizing that should be quicker by 58.1%, 60.9% respectively. When called to 119 all health and non-health major college students responded highest by 55.5%, 53.3% respectively that we must receive first-aid treatment direction from a doctor. In question about "119 rescue ambulance car must be made the pay system", all health and non-health major college students responded 74%, 80% respectively in "not so" item. There was significant difference in major department(p<0.05). In conclusions, In oder to provide superior rescue first aid service to people, a public health doctor should be placed in the situation room inside the fire station so that the doctor could instruct the proper emergency treatment suitable for each situation to the rescue first aid team. Also, national education about a first-aid treatment that do to all people is necessarily necessary in emergency delivery system and this should be spread extensively through school education and broadcasting medium and education should be gone side by side, and see that will can save emergency patients' life which is more when these education consists continuously fixed period for public institution of policeman, fire officer etc. specially. And for reinforcement of patient transfer system, public organization must procure special ambulance car so that emergency patient receive first aid treatment while transfer.

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