• 대한교통학회지
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• 제30권1호
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• pp.31-43
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• 2012

한국이 UN 자동차 법규 표준화 기구(WP29) 주관의 소형차 배출가스 시험방법 국제 표준화(WLTP/DHC) 연구에 참여하게 됨에 따라 우리나라의 도로 종류 별, 주행 시간대 별 주행패턴 측정이 요구되었다. 이에 본 연구에서는 WP29에서 제안한 주행패턴 표준화 방법을 토대로, 우리나라의 도로 교통 특성을 반영한 실 도로 주행패턴을 측정하고, 대표성을 갖는 도로 종류 별 주행 시간대별 총 7가지 유형의 주행패턴을 분석하였다. 이를 위해 이동식 차량활동도 모니터링 장비(PAMS)를 이용하여 35,410km의 실주행자료를 수집하였으며, 각 유형별로 분석된 주행패턴은 서로 유의한 차이가 있는 것으로 나타났다.

• 한국실천공학교육학회논문지
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• 제1권1호
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• pp.66-71
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• 2009

시뮬레이터는 산업교육에 있어서 유용하게 활용되고 있다. 특히 고도의 가치산업이나 위험한 시스템에 대한 교육을 실시하기 위해서 사용하기에 적합한 방법이다. 또한, 이론교육에서 체험형 교육으로 전향되는 산업교육에 있어서는 교육의 효과를 위하여 필요하다. 따라서 현장에서 실무에 도움이 되도록 LPG 이송방법에 대한 교육극대화를 위하여 이론교육과 체험교육의 중간 매개체 역할의 장비를 개발하여 교육에 적용하였다. 교육에 적용한 결과 교육장비가 이송시스템 이해도가 4.86점/5점, 현장에서 활용도는 4.47점/5점, 장비의 만족도는 4.48점.5점으로 나왔다. LPG 이송시스템 교육장비(시뮬레이터)가 교육에 활용시 효과적인 것으로 판단된다.

• 한국안전학회지
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• 제31권4호
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• pp.156-163
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• 2016

There exists required safety integrity level (SIL) to assure safety in accordance with international standards for every electrical / electronics / control equipment or systems with safety related functions. The SIL is allocated from lowest level (level 0) to highest level (level 4). In order to guarantee certain safety level that is internationally acceptable, application of methodology for SIL allocation and demonstration based on related international standards is required. However, the theoretical and practical study for safety integrity level is barely under way in the domestic railway industry. This research studied not only the global process of SIL allocation to guarantee safety in accordance with international standards for safety related equipment and system, but the quantitative methodology based on international standard and the semi-quantitative methodology as alternative way for SIL allocation. Specifically, the systematic SIL allocation for platform screen door system of railway is studied applying the semi-quantitative methodology in order to save much time and effort compared to quantitative method.

• 한국항해항만학회지
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• 제44권2호
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• pp.65-72
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• 2020

Mankind has been using ships for more than 5,000 years and has developed a range of related technologies. However, despite such a long history, compared to aircraft with a history of approximately one century, the pace of progress has been markedly slow. Even though technological progress of ships or the installation of various navigation equipment have been achieved, seaborne collisions have occurred quite frequently. This study analyzed the TCAS( Traffic Collision Avoidance System) that has contributed to the prevention of collisions with other transport methods including aircraft to suggest a collision avoidance system that can be deployed for ships. To apply the technologies applied to aircraft that move in 3D to ships that move in 2D, the difference in the operational environment between the two modes was analyzed to identify elements that need to be applied to ships. The suggested display of data on the collision prevention system is one that manipulates the augmented reality display device used in automobiles that over the past few years has undergone rapid development. Based on the presentation of technological elements that need to be considered when adopting the SCAS or the Seaborne Collision Avoidance System as suggested in this study, the authors hope to contribute to the prevention of collisions.

• 한국안전학회지
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• 제30권6호
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• pp.164-173
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• 2015

There exists required safety integrity level (SIL) to assure safety in accordance with international standards for every electrical / electronics / control equipment or systems with safety related functions. The SIL is allocated from lowest level (level 0) to highest level (level 4). In order to guarantee certain safety level that is internationally acceptable, application of methodology for SIL allocation and demonstration based on related international standards is required. However, application standard differs from every industry in domestic or international for application on mythology for allocation and demonstration of SIL. Application or assessment is not easy since absence on clear criteria or common definition. This research studied not only fundamental concept of SIL required to guarantee safety in accordance with international standards for safety related equipment and system, but different types of methodologies for SIL allocation. Specifically, SIL allocation for Platform Screen Door system of railway is studied applying methodology of severity of accidents and risk graph among different methodologies for SIL allocation.

• 한국유체기계학회 논문집
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• 제12권6호
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• pp.13-17
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• 2009

Ejector is an equipment devised for making use of the low pressure occurring from the fast fluid injection and it is a transportation equipment which can obtain vacuum using the kinetic energy of the fluid. This ejector system is, nowadays, widely used for construction machinery, heavy equipments, the cooling and ventilation of electronic devices and for the various fluid transportation and pumps. In this study, it is attempted to perform a numerical analysis and an experiment to find out the characteristics of fluid quantity, velocity and the pressure distribution of the induction pipe by changing the length and the radius ratio of the nozzle of ejector. From the results, it is investigated that the distributions of velocity and pressure of induction pipe attached are changing with the length and the radius ratio of the nozzle. In addition, it is shown that for the small and large ejector, the efficiency is the maximum when the length of the nozzle arrived to the neck of the ejector, however, if it is installed at below or above the neck the efficiency is rather decreased.

• 한국기후변화학회지
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• 제7권2호
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• pp.177-184
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• 2016

Recently, the need for technology development of commercial vehicle fuel consumption has emerged. Fuel economy improvement of transport equipment and transportation efficiency, and increasing attention to the logistics cost reduction measures. Increasing attention to the logistics cost reduction measures by fuel economy improvement of transport equipment and transportation efficiency. In this study, we have installed aerodynamic reduction device (side skirt, boat tail) to 14.5 ton cargo trucks and 45 ft tractor-trailers. And the fuel consumption was compared installed before and after. Fuel economy assessment for the aerodynamic reduction value device was tested by modifying the SAE J1321 Joint TMC/SAE Fuel Consumption Test Procedure - Type II test in according domestic situation. Greenhouse gas reductions were calculated in accordance with the scenario, including fuel consumption test results. When the 14.5 ton cargo trucks has been equipped with side skirts and boat tail, it confirmed the improvement in fuel efficiency of 4.72%. One Heavy-duty truck's the annual greenhouse gas reductions value are $6.86ton\;CO_2\;eq$. And if applying the technology to more than 50% of registered 15 ton trucks, greenhouse gas reductions are calculated as $686,826ton\;CO_2\;eq./yr$.

• Structural Engineering and Mechanics
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• 제85권1호
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• pp.119-133
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• 2023

Impact event is the key factor influencing the operational state of the mechanical equipment. Additionally, nonlinear factors existing in the complex mechanical equipment which are currently attracting more and more attention. Therefore, this paper proposes a novel hybrid-separate identification strategy to solve the force identification problem of the nonlinear structure under impact excitation. The 'hybrid' means that the identification strategy contains both l1-norm (sparse) and l2-norm regularization methods. The 'separate' means that the nonlinear response part only generated by nonlinear force needs to be separated from measured response. First, the state-of-the-art two-step iterative shrinkage/thresholding (TwIST) algorithm and sparse representation with the cubic B-spline function are developed to solve established normalized sparse regularization model to identify the accurate impact force and accurate peak value of the nonlinear force. Then, the identified impact force is substituted into the nonlinear response separation equation to obtain the nonlinear response part. Finally, a reduced transfer equation is established and solved by the classical Tikhonove regularization method to obtain the wave profile (variation trend) of the nonlinear force. Numerical and experimental identification results demonstrate that the novel hybrid-separate strategy can accurately and efficiently obtain the nonlinear force and impact force for the nonlinear structure.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.624-631
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• 2022

Highway Rest Areas are envisioned to provide an accessible space for rest and parking for travelers, especially those driving a long distance. In addition, modern highway Rest Areas provide many amenities to highway users, including wifi service, picnic tables, litter barrels, running water, public telephones, and sometimes even free coffee. Various studies were conducted in the domain of Rest Area facility design and their operating costs in different states; however, limited studies were conducted on the maintenance costs of these facilities. Therefore, this study's main objective is to compute the annual maintenance cost of Rest Areas in the state of Nevada. This study also analyzes the main cost categories of the maintenance works. The raw cost data of Nevada Rest Area maintenance from 1990 to 2012 were collected from the Nevada Department of Transportation (NDOT). Results show that the maintenance cost fluctuated over the study period; the maintenance cost decreased from 1991 to 2004 and then increased until 2012. The primary cost categories of maintenance work are labor, equipment, and material costs. Among these, labor cost was the largest category with 56 percent of the total maintenance cost, followed by equipment cost and material cost. The findings of this study may help NDOT and other transportation agencies plan their budget for future Rest Area maintenance activities.

• 무역학회지
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• 제47권4호
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• pp.271-292
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• 2022

In Korea, the road transport industry is pointed out as a major cause of air pollutants, so management control is needed. Existing studies used only positive input and output variables to measure regional efficiency. However, it is necessary to consider the environmental pollution problem in efficiency analysis. In this study, an undesirable SBM analysis using CO₂ was conducted to measure efficiency of domestic regions. In addition, SDM was conducted to examine the ripple effect between domestic regions. As a result of the analysis, the efficiency of the capital area such as Seoul, Gyeonggi, and Incheon was high in the road transport industry. However, the efficiency of the road transportation industry in Daegu and Gangwon was low. In the SDM analysis, it was found that the regional equipment capabilities had a great influence on efficiency. In order to improve efficiency, it is necessary to increase and improve the equipment capacity of the road transport industry.