• Title/Summary/Keyword: Impact Speed

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Study in the development of High Speed Rail(HSR) and its influence (고속철도의 발전과 영향력)

  • Lee, Yong-Sang;Mun, Dae-Seop
    • Journal of the Korean Society for Railway
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    • v.10 no.1 s.34
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    • pp.23-37
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    • 2007
  • Since 1964, HSR, which was opened in Japan, has had a hoge impact on the world. Historically, HSR has similar characteristics to the Roman Road, which promoted rapid movement and hada great influence on international society as transport infrastructure. Recently the development of HSR has become more rapid because of economic, environmental and external cost concern, emphasizing Environmentally Sustainable Transport(EST). In particular, the external cost has become more important factor for justifying HSR. The successful factors of HSR are high demand and cost minimal construction costs. There are two successful HSR models, the Japanese and the French. The former operates based on high demand oriented and the latter focuses on its minimizing costs. The demand orientated model means HSR carries over 100,000 passengers per day as in Japan and Far East Asian countries. The cost minimized model focuses on lower operation and construction costs as in France. In particular, Germany carries both passengers and freight on HSR. The construction costs in Germany are in between those of Japan and France. In future, Korea, Taiwan and China HSR will follow Japan's successful model because of high population density and concentration of economic activity along railway lines. This paper supports Vickerman's argument that HSR is justified where there is a demand of between 12 million and 15 million railway passenger a year(about 40thousand persons/day) between two urban center. This will be shown in the future in Korea, in Taiwan and China. Finally, this paper reviews that HSR activates at 250km/h for dedicated new lines and 200km/h for upgraded lines. In particular, it is successful in area of high population density and cost minimizing technology.

An Analysis of Economic Evaluation Related to Lane Departure Warning System (주행로이탈예방지원기술 관련 경제성평가 분석)

  • Ryu, Byung-Yong;Choi, Ji-Eun;Bae, Sang-Hoon
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.8 no.5
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    • pp.85-97
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    • 2009
  • Continuous increase of traffic demand has caused confirmed congestion, fuel consumption, emission, safety, etc. as serious social problems at the present time. The Smart Highway Project has been conducted by the supervision of Ministry of Land, Transport and Maritime Affaire to solve such problems since 2007. The Smart Highway Project includes LDWS (Lane Departure Warning System), a system to prevent broadside collisions and accidents, as a sub-technology of road-vehicle associating technologies. This system warns drivers when their vehicle deviates from the lane where they are traveling at high-speed on the highway. In this paper, the LDWS was evaluated using CBA to analyze the socio-economic consequences. Estimated benefits include reduction of accidents and convenience of drivers. In addition, the economics according to the distribution rate is various when it comes to Lane Departure Warning Technology, the economics of both cases - positive scenario and negative scenario, which was analyzed. As a result, the Benefit-Cost ratio(B/C) of negative scenario showed 0.97 in 2020 and 1.36 in 2030 while B/C ratio of the positive scenario showed 1.04 in 2020 and 1.59 in 2030, which indicated that the higher distribution rate is, the higher the economics generates. Therefore, it is judged that the introduction of Lane Departure Warning Technology will result in high economics.

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Influence of Pinewood Nematode, Bursaphelenchus xylophilus, on the Growth of Endoparasitic Fungus Esteya vermicola (Endoparasitic fungus Esteya vermic의 성장에 미치는 소나무 선충 Bursaphelenchus xylophilus의 영향)

  • Wang, Chun-Yan;Lee, Chung-Ha;Lee, Mi-Ra;Yun, Beom-Sik;Liu, Lei;Wang, Zhen;Fang, Zhe-Ming;Zhang, Dong-Liang;Li, Zheng;Sung, Chang-Keun
    • Journal of Life Science
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    • v.20 no.5
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    • pp.644-648
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    • 2010
  • The influence of nematodes on nematophagous fungi has seldom been investigated. In the present study, the influence of pinewood nematode on its endoparasitic fungus, Esteya vermicola, was investigated systemically. Although both nematodal metabolite and nematodal homogenate could stimulate and speed up the growth of E. vermicola, the impact of nematodal metabolite was slightly higher than that of nematodal homogenate. In addition, a method was developed to investigate the influence of volatiles, discharged by pinewood nematodes in their metabolic process, on the growth of E. vermicola. Reproductive results were given and confirmed that nematodal volatiles have no influence on the cell growth of E. vermicola. This study may provide information for the application of E. vermicola as biological control agent of pinewood nematode.

A Study on the Characteristic of Conversion Efficiency for Three-way Catalyst in Hydrogen-Natural Gas Blend Fueled Engine (수소-천연가스 혼합연료 엔진의 삼원촉매 전환효율 특성 연구)

  • Park, Cheol-Woong;Yi, Ui-Hyung;Kim, Chang-Gi;Lee, Janghee
    • Journal of the Korean Institute of Gas
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    • v.20 no.6
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    • pp.23-30
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    • 2016
  • The conventional natural gas engine realized lean combustion for the improved efficiency. However, in order to cope with exhaust gas regulations enforced gradually, the interest has shifted at the stoichiometric mixture combustion system. The stoichiometric mixture combustion method has the advantage of a three-way catalyst utilization whose purification efficiency is high, but the problem of thermal durability and the fuel economy remains as a challenge. Hydrogen-natural gas blend fuel (HCNG) can increase the rate of exhaust gas recirculation (EGR) because the hydrogen increases burning speed and lean flammability limit. The increase in the EGR rate can have a positive impact on heat resistance of the engine due to the decreased combustion temperature, and further can increase the compression ratio for efficient combustion. In this study, to minimize the exhaust emission developed HCNG engine with stoichiometric combustion method, developed three-way catalyst was applied to evaluate the conversion characteristics. The tests were carried out during the steady state and transient operating conditions, and the results were compared for both the conventional and proto-three-way catalyst of HCNG engine for city buses.

Evaluation of the Behavior of Dredged Materials in Ocean Dumping Area (해양투기장에서 준설토의 투기에 따른 거동 평가)

  • Lee, Joong-Woo;Oh, Dong-Hoon;Lee, Seung-Chul;Kim, Hyung-Chul;Kim, Kang-Min
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.433-438
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    • 2006
  • When we consider to develop a new harbor, the most important factor, we think, is the lowest water depth of waterway and approaching channel for safe navigation of vesse. The existing harbors have been being dredged to meet the international trend of jumbo sized vessels by adopting the new design criteria. As the dredged materials over the expected at the design level were common and there are still lack of land based reclamation area, we have no choice to discharge the dredged materials in open sea area. In this study, we analysed the behavior of discharged materials at the dumping area of offshore open sea, which were collected from the dredging work at the waterway in Busan New Port. We measured the tidal currents and analyzed the waters of dumping site after the dumping work. these were used to evaluate the numerical models. Suspended Solids(SS) were introduced to the diffusion model. Because of the characteristics of the dumping site, the speed of initial diffusion and settle down of the discharged materials was so fast. Therefore, we believe that the dumped materials do not cause a significant impact to the marine environment.

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Conjunctive Boolean Query Optimization based on Join Sequence Separability in Information Retrieval Systems (정보검색시스템에서 조인 시퀀스 분리성 기반 논리곱 불리언 질의 최적화)

  • 박병권;한욱신;황규영
    • Journal of KIISE:Databases
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    • v.31 no.4
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    • pp.395-408
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    • 2004
  • A conjunctive Boolean text query refers to a query that searches for tort documents containing all of the specified keywords, and is the most frequently used query form in information retrieval systems. Typically, the query specifies a long list of keywords for better precision, and in this case, the order of keyword processing has a significant impact on the query speed. Currently known approaches to this ordering are based on heuristics and, therefore, cannot guarantee an optimal ordering. We can use a systematic approach by leveraging a database query processing algorithm like the dynamic programming, but it is not suitable for a text query with a typically long list of keywords because of the algorithm's exponential run-time (Ο(n2n1)) for n keywords. Considering these problems, we propose a new approach based on a property called the join sequence separability. This property states that the optimal join sequence is separable into two subsequences of different join methods under a certain condition on the joined relations, and this property enables us to find a globally optimal join sequence in Ο(n2n1). In this paper we describe the property formally, present an optimization algorithm based on the property, prove that the algorithm finds an optimal join sequence, and validate our approach through simulation using an analytic cost model. Comparison with the heuristic text query optimization approaches shows a maximum of 100 times faster query processing, and comparison with the dynamic programming approach shows exponentially faster query optimization (e.g., 600 times for a 10-keyword query).

An Experimental Analysis for System Optimization to Reduce Smoke at WOT with Low Volatile Fuel on Turbo GDI Engine (저 기화성 연료를 사용한 직접분사식 과급 가솔린엔진에서 전 부하 스모크 저감을 위한 시스템 최적화에 관한 연구)

  • Kim, Dowan;Lee, Sunghwan;Lim, Jongsuk;Lee, Seangwock
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.1
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    • pp.97-104
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    • 2015
  • This study is a part of the high pressure injection system development on the Turbo GDI engine in order to reduce smoke emission in case of using the low volatile(high DI) fuel which is used as normal gasoline fuel in the US market. Firstly, theoretical approach was done regarding gasoline fuel property, performance, definition of particle matters and its creation as well as problems of the high DI fuel. In this experimental study, 2L Turbo GDI engine was selected and optimized system parameter was inspected by changing fuel, fuel injection mode (single/multiple), fuel pressure, distance between injector tip and combustion chamber, start of injection, intake valve timing in engine dyno at all engine speed range with full load. In case of normal gasoline fuel, opacity was contained within 2% in all conditions. On the other hands, in case of low volatile fuel (high DI fuel), it was confirmed that the opacity was rapidly increased above 5,000 rpm at 14.5 ~ 20 MPa of fuel pressure and there were almost no differences on the opacity(smoke) between 17 MPa and 20 MPa fuel pressure. According to the SOI retard, smoke decrease tendency was observed but intake valve close timing change has almost no impact on the smoke level in this area. Consequently, smoke decrease was observed and 16% at 6000rpm respectively with injector washer ring installed. By removing injector washer to make injector tip closer to the combustion chamber, smoke decrease was observed by 46% at 5,500 rpm, 42% at 6,000 rpm. It is assumed that the fuel injection interaction with cylinder head, piston head, intake and exhaust valve is reduced so that impingement is reduced in local area.

Comparisons of Empirical Braking Models for Freight Trains Using P4a Distribution Valve (P4a 분배밸브를 사용하는 화물열차의 경험적 제동모델들의 비교)

  • Choi, Don Bum;Kim, Min-Soo;Lee, Kangmi;Kim, Young-Guk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.1
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    • pp.61-69
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    • 2020
  • This study examined the braking characteristics of a heavy haul freight train with P4a distribution valves applied to domestic high-speed freight trains. A freight train was composed of 50 cars, which is twice the normal operation. A braking test was performed to confirm the characteristics of the braking of a heavy haul. The brake cylinder pressures were measured for emergency and service braking on the 1st, 10th, 20th, 30th, and 50th cars. Because the brake signal is transmitted to the pressure through the braking tube connected to the end of the train, the rear vehicle is braking later than the vehicle ahead. Therefore, it is necessary to predict the brake pressures in all cars in a train to supplement the results of the limited tests and calculate the braking distance. The pressure in each car was determined using empirical models of linear interpolation, stepwise, and exponential models, which provided reliable information. The predictive results of the empirical models were compared with the measured results, and the exponential model was predicted relatively accurately. These results are expected to contribute to the safe operation of heavy haul freight trains and can be used to predict the braking distance and calculate the level of impact between vehicles during braking.

Evaluation of Carbon Balance for Carbon Sink/Emission with Different Treatments in Paddy Field (벼논에서 양분관리별 탄소의 흡수·배출에 대한 탄소수지 평가)

  • Kim, Gun-Yeob;Lee, Jong-Sik;Lee, Sun-Il;Jeong, Hyun-Cheol;Choi, Eun-Jung;Na, Un-sung
    • Korean Journal of Environmental Biology
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    • v.35 no.4
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    • pp.715-725
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    • 2017
  • Importance of climate change and its impact on agriculture and environment has increased with the rise in the levels of Green House Gases (GHGs) in the atmosphere. To slow down the speed of climate change, numerous efforts have been applied in industrial sectors to reduce GHGs emission and to enhance carbon storage. In the agricultural sector, several types of research have been performed with emphasis on GHGs emission reduction; however, only a few work has been done in understanding the role of carbon sink on reduction in GHGs emission. In this study, we investigated ecosystem carbon balance and soil carbon storage in an agricultural paddy field. The results obtained were as follows: 1) Evaluation of soil C sequestration in paddy field was average 3.88MgCO2ha1 following NPK+rice straw compost treatment, average 3.22MgCha1 following NPK+hairy vetch treatment, and average 1.97MgCO2ha1 following NPK treatment; and 2) Net ecosystem production (NEP) during the paddy growing season was average 14.01MgCO2ha1 following NPK+hairy vetch treatment, average 12.60MgCO2ha1 following NPK+rice straw compost treatment, and average 11.31MgCO2ha1 following NPK treatment. Therefore, it is proposed that organic matter treatment can lead to an increase in soil organic carbon accumulation and carbon sock of crop ecosystem in fields compared to chemical fertilizers.

The Improvement of Point Cloud Data Processing Program For Efficient Earthwork BIM Design (토공 BIM 설계 효율화를 위한 포인트 클라우드 데이터 처리 프로그램 개선에 관한 연구)

  • Kim, Heeyeon;Kim, Jeonghwan;Seo, Jongwon;Shim, Ho
    • Korean Journal of Construction Engineering and Management
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    • v.21 no.5
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    • pp.55-63
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    • 2020
  • Earthwork automation has emerged as a promising technology in the construction industry, and the application of earthwork automation technology is starting from the acquisition and processing of point cloud data of the site. Point cloud data has more than a million data due to vast extent of the construction site, and the processing time of the original point cloud data is critical because it takes tens or hundreds of hours to generate a Digital Terrain Model (DTM), and enhancement of the processing time can largely impact on the efficiency of the modeling. Currently, a benchmark program (BP) is actively used for the purpose of both point cloud data processing and BIM design as an integrated program in Korea, however, there are some aspects to be modified and refined. This study modified the BP, and developed an updated program by adopting a compile-based development environment, newly designed UI/UX, and OpenGL while maintaining existing PCD processing functions, and expended compatibility of the PCD file formats. We conducted a comparative test in terms of loading speed with different number of point cloud data, and the results showed that 92 to 99% performance increase was found in the developed program. This program can be used as a foundation for the development of a program that reduces the gap between design and construction by integrating PCD and earthwork BIM functions in the future.