• 한국수소및신에너지학회논문집
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• 제17권3호
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• pp.279-285
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• 2006

Recirculation for the unreacted fuel is necessary to improve the overall efficiency of the fuel cell system and to prevent fuel starvation since the fuel cell for a vehicle application is a closed system. In case of the automotive fuel cell, the ejector which does not require any parasitic power is good for the performance improvement and easy operation. It is essential to design the customized ejector due to the lack of the commercial ejector corresponding to the operating conditions of the fuel cell systems. In this study, the design methodology for the ejector customized to an automotive fuel cell is proposed. The model based sensitivity analysis prevents the time-consuming redesign and reduces the cost of developing ejector. As a result, the customized ejector to meet the desired performance within overall operating range has developed for the PEMFC automotive system.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.157-161
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• 2005

In the FY 2003, the number of registered vehicles in Korea reached 14 million, which is 7.7% increase from the previous year. The increase of number of vehicles has caused a lot of social problem with enormous costs. The social costs related to the vehicles includes environmental costs resulting from pollution and scraping of vehicles, those resulting from life-saving and repairing from car accidents and so on. There have been m any efforts to reduce the social costs in m any areas. As a part of the efforts, there are recent grow ing interests on the damageability & repairability in related industries. In this study, we investigated the cases of two different types of bum per stay. Futhermore, we analyzed their effects on damageability & repairability and reduction of repair cost. So we found that if the manufacturers design new cars with good damageability & repairability, then the total repair cost in crash will be reduced.

• 한국수소및신에너지학회논문집
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• 제30권4호
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• pp.338-346
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• 2019

During last years, hydrogen refueling infrastructure test and devices research for hydrogen station presented a significant growth consisting of the commercialization of fuel cell electric vehicles (FCEVs). However, we still have many challenges for making commercial hydrogen stations such as increased safety and cost reduction. This study demonstrates the low cost hydrogen storage tank (type 2) and effective winding method for high pressure hydrogen storage. We use numerical analysis to verify stress changes inside the wire according to the winding condition. Also liner size, winding wire size and wire tension were studied for the safety and cost down. Results show that the stress of winding wire decreased with increased winding angle and increased the liner diameter. On the other hand, the stress of winding wire increased according to the increased wire thickness and tension.

• 산업공학
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• 제15권4호
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• pp.439-443
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• 2002

In this paper, we study to evaluate the relative time required to perform the CT scanning in the PACS versus a film-based system and helical versus non-helical studies. Time studies were performed in 175 consecutive CT scanning. Images from 85 examinations were electronically transferred to a PACS, and 90 were printed to film. The time required to obtain and electronically transfer the images or print the images to film and make the current and previous studies available to the radiologists for interpretation was recorded. The time required for a radiological technologist to complete a CT test was reduced by 43% with the PACS compared with the film-based system and nonhelical was reduced 10~20% with helical studies. This reduction was due to the elimination of a transfer and printing, such as the printing at window or level settings. The use of PACS can result in the elimination of time tasks for the radiological technologist, resulting in marked reduction in examination time. This reduction can result in decreased cost and increased productivity in PACS operation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.638-643
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• 2011

The aluminum soundproofing panel used to the traffic noise reduction will judge with the material to improve because the CO2 emission is greater than other soundproofing panel such as plastic soundproofing panel. Also, if the air-passing soundproofing panel which can endure the fast wind velocity will be developed, it judged that it can reached to the target of low CO2 traffic technology development using the reduction of material cost and the lower consumption of steel. The objective of this study is to improve the soundproofing panel and to develop the air-passing soundproofing panel for the replacement of aluminum sound proofing panel which is more emit CO2 than other soundproofing panel. And, we tried to develop the reduction technology of CO2 emission through the development of air-passing soundproofing panel. At first, the flow and noise simulation were conducted for the purpose of the calculation of wind pressure on soundproofing wall and noise exposure level on receiver points according to the open ratio of air-passing soundproofing panel. And the 1st and 2nd mockup of air-passing soundproofing panel were made, and the design load test were conducted for these mockup.

• Journal of Welding and Joining
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• 제23권5호
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• pp.43-48
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• 2005

Conventional non-destructive techniques for inspection of the weld in pipelines require significant test time and high cost. Ultrasonic guided waves have been widely studied and successfully applied to various non-destructive tests with advantage of the long-range inspection. In this paper, a study on the application of ultrasonic guided waves to the long-range inspection of the pipeline is presented using a long-range guided wave inspection system, Wavemaker SE16, GUL. The characteristics and setup of the long-range guided wave inspection system and experimental results in pipes of with various diameter are introduced. The experimental results in mock-up pipes with cluster type detects show that the minimum detectable wall thickness reduction with this guided wave system is $2\~3\%$ in the pipe cross section area. And the wall thickness reduction of $5\%$ in cross section area can be detected when actual detection level is used. Therefore, the applicability of the guided wave systeme to long-range inspection of wall thickness reduction in pipes is verified.

• 디지털융복합연구
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• 제8권4호
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• pp.185-204
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• 2010

본 연구는 정부기관의 정보시스템을 통합한 정부통합전산센터의 사례를 중심으로 IT 통합의 경제적 성과를 측정하였다. 성과측정을 위해 측정항목은 TCO 비용항목에 기반하여 사전 2개 기관에 대한 시범분석을 통하여 최종 측정항목을 개발하였다. 측정결과, IT 자산비용이 가장 큰 경제적 성과로 성과의 대부분을 차지하고 있으며, 다음으로 IT 지원비용과 IT 관리비용의 순으로 경제적 성과가 있는 것으로 조사 및 분석되었다. 본 연구의 주요 의의로는 국내외 선행연구 검토를 토대로 TCO 방법론에 따라 2개 기관을 대상으로 시범분석 과정을 통하여 TCO 측정항목을 IT 통합성과 측정에 적합하도록 개발하였으며, 동 측정항목을 기준으로 신뢰성 있는 현황자료를 토대로 객관적으로 경제적 성과를 측정하였다는 점이다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.607-610
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• 2004

It is still not sufficient for the famous embedded software test methods such as Finite State Machine, Software Cost Reduction and model coverage based test case generation, to pinpoint where bugs hang around and to figure out what makes the bugs. A new approach to ameliorate the drawbacks is proposed in this paper. In the approach, we define a generic model for embedded software. And we also define failure mechanism for embedded software, and a way to generate test cases based on it.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.188-191
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• 2007

This paper shows the Development of In-tank pressure regulator and Solenoid Valve used in FCV(Fuel Cell Vehicle). We have developed new type of Regulator and Solenoid through analysis of the structure and characteristics of component of FCS(Fuel Cell System) from the advanced technology. Now it is possible to localize the component by making use of the development of Regulator and Solenoid made by us. Regulator and Solenoid is a equipment to control hydrogen pressure supplied into a stack. Therefore, outlet pressure, a flow of fluid and temperature are important parameters according to a inlet pressure. And leak test, endurance test and burst test should be done to guarantee the performance and safety of Regulator and Solenoid used in the fuel of high pressure. Also, Hydrogen friendly materials are applied to inner parts of the Regulator, Solenoid and weight reduction is done to cost saving in part not related to performance. As a result, we have proven the good performance and reliability in endurance of Regulator, Solenoid and will make an development in performance as well as durability to ensure industrialization.

• 기술사
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• 제34권1호
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• pp.27-34
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• 2001

On 16Dec. 1999, It was 100 years since the opening the first railroad section of 33.2km on Sep. 1899, Korea High Speed Railroad had a successful trial run of 200km/h on test track section. And the test speed 300km/h was achieved an 28 June 2000 during continuous commissioning. In the 21st century, the High Speed Railroad will be opened commercially in Korea and will contribute to technical development. Now, it is necessary to re-evaluate the role of railroad in modern society and to activate the railroad system. Ultimately, the competitive power of nation will be strengthened with energy saving, reduction of pollution and transportation cost. It conclusion the railroad system have to be expaned about 50% of total transportation to make preparations for reopening of Eurasia silk route through KyungEu railroad connection.