• 한국산업보건학회지
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• 제17권2호
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• pp.144-152
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• 2007

Diesel vehicles are a significant source of fine carbon particle emissions including polynuclear aromatic hydrocarbons (PAHs). Urinary 1-hydroxypyrene (1-OHP) is firmly established as a useful biomarker of PAHs uptake in human. To investigate the exposure effect of PAHs in miners according to using diesel truck which was for transportation of ore, we measured urinary 1-OHP as the PAHs exposure biomarker, and analyzed the relationship between urinary 1-OHP concentration and using diesel truck. The study was performed on 118 workers (56 miners in factories using diesel truck, 62 miners in factories non-using diesel truck) and 21 controls. Urine samples were obtained at the end of shift on the survey day. There was no significance in comparison with the mean concentrations on urinary 1-OHP by age, BMI, work duration, smoking, drinking and ventilation type. But significant difference were found among urinary 1-OHP concentrations on factories according to using diesel truck (p=0.000). The urinary 1-OHP mean concentration on underground miners using diesel truck ($0.54{\mu}mol/mol$ creatinine) was higher than those of surface miners using diesel truck ($0.33{\mu}mol/mol$ creatinine, p=0.028), underground miners non-using diesel truck ($0.32{\mu}mol/mol$ creatinine, p=0.001) and controls ($0.22{\mu}mol/mol$ creatinine, p=0.000). In comparison with using status diesel truck, the urinary 1-OHP mean concentration of underground miners using diesel trucks was higher than those of other mine status. The study results would be beneficial to future environmental and biological studies of PAHs exposure to diesel exhaust in mines.

• Wind and Structures
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• 제26권1호
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• pp.35-43
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• 2018

This paper describes the effect of different testing parameters (configuration of infrastructure and truck position on road) on truck aerodynamic coefficients under cross wind conditions, by means of a numerical approach known as Large Eddy Simulation (LES). In order to estimate the air flow behaviour around both the infrastructure and the truck, the filtered continuity and momentum equations along with the Smagorinsky-Lilly model were solved. A solution for these non-linear equations was approached through the finite volume method (FVM) and using temporal and spatial discretization schemes. As for the results, the aerodynamic coefficients acting on the truck model exhibited nearly constant values regardless of the Reynolds number. The flat ground is the infrastructure where the rollover coefficient acting on the truck model showed lowest values under cross wind conditions (yaw angle of $90^{\circ}$), while the worst infrastructure studied for vehicle stability was an embankment with downward-slope on the leeward side. The position of the truck on the road and the value of embankment slope angle that minimizes the rollover coefficient were determined by successfully applying the Response Surface Methodology.

• Journal of Construction Engineering and Project Management
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• 제7권2호
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• pp.11-18
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• 2017

The cycle time of construction equipment for earthwork operations has a significant impact on project productivity. Elements that directly impact a haul vehicle's cycle time must be identified in order to accurately quantify the haul cycle time and implement strategies to decrease it. The objective of this research is to scientifically identify and quantify variables that have a significant impact on the cycle time of a dump truck used for earthwork. Real-time location data collected by GPS devices deployed in an active earthwork moving construction site was analyzed using statistical regression. External data including environmental components and haul road conditions were also collected periodically throughout the study duration. Several statistical analyses including a variance analysis and regression analysis were completed on the dump truck location data. Collected data was categorized by stage of the dump truck cycle. Results indicate that a dump truck's enter idle time, exit idle time, moving speed and driver visibility can significantly impact the dump truck cycle time. The contribution of this research is the identification and analysis of statistically significant correlations of variables within the cycle time.

• 드라이브 ㆍ 컨트롤
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• 제16권3호
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• pp.1-7
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• 2019

The reach truck, which is mainly used in warehouses, is required to have high-mast to improve its working efficiency and space utilization. The high-mast takes advantage of more vertical space but severe vibrations are easily generated at the end of the high-mast. These vibrations may cause a collision or misplacement of loading location at work. In this study, the vibration characteristics of a three-stage high-mast of a reach truck are analyzed, and an active vibration controller verified through a similar experiment is designed to reduce this vibration. A similar experiment for reach truck mast verifies the performance of the active vibration controller. By applying an active vibration controller designed for a real reach truck, the operations of the reach truck are made more efficient through the reduction of the vibration amplitude.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2000년도 추계학술대회 학술발표 논문집
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• pp.393-398
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• 2000

In this paper, we propose an Intelligent Monitoring Network System(IMNS) for the truck scale balance system. Truck scale balance system consis of three parts; Load cell part, Indicator part, and Junction box part. IMNS is attached to Junction box in truck scale balance system. Even if Load cell have been some problems, a truck scale balance system still has been run to determine, the values involved error. Therefore prosed system is has concentrated on Load cell part. Other Parts have been changed a portion of circuit for monitoring system.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(3)
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• pp.41-44
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• 2000

In this paper, we propose an Intelligent Monitoring Network System(IMNS) for The truck scale balance system. Truck scale balance system consis of three parts； Load cell part, Indicator part, and Junction box part. IMNS is attached to Junction box in truck scale balance system. Even if Load cell have been some problems, a truck scale balance system still has been run to determine, the values involved error. therefore prosed system is has concentrated on Load cell part. Other Parts have been changed a portion of circuit for monitoring system.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2002년도 춘계학술대회
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• pp.285-294
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• 2002

This study is focused on the operation of truck with conscious for environmental logistics system to reduce empty truck movements, and to control running empty truck. With the logistics function, road transport represents the biggest environmental threat. Using nonrenewable natural resources, contributing to air and noise pollution, trucks are environmentally unfriendly. Any steps to reduce transport activity will help minimize negative impact. In particular, noxious emissions must be reduced, but in the long term more environmentally friendly vehicles are required.

• International Journal of Automotive Technology
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• 제6권3호
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• pp.221-227
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• 2005

Aim of this study is to investigate an aerodynamic effect of a drag-reducing device on a heavy-duty truck. The vehicle experiences two different kinds of aerodynamic forces such as drag and uplifting force (or downward force) as it is traveling straight forward at constant speed. The drag force on a vehicle may cause an increase of the rate of fuel consumption and driving instability. The rolling resistance of the vehicle may be increased as result of the negative uplifting or downward force on the vehicle. A device named roof-fairing system has been applied to examine the reduction of aerodynamic drag force on a heavy-duty truck. As for a engineering design information, the drag-reducing system should be studied theoretically and experimentally for the best efficiency of the device. Four different types of roof-fairing model were considered in this study to investigate the aerodynamic effect on a model truck. The drag and downward force generated by vehicle has been obtained from numerical calculation conducted in this study. The forces produced on four fairing models considered in this study has been compared each other to evaluate the best fairing model in terms of aerodynamic performance. The result shows that the roof-fairing mounted truck has bigger negative uplifting or downward force than that of non-mounted truck in all speed ranges, and drag force on roof-fairing mounted truck has smaller than that of non-mounted truck. The drag coefficient $(C_D)$ of the roof-fairing mounted truck (Model-3) is reduced up to $41.3\%$ than that of non-mounted trucks (Model-1). A downward force generated by a roof-fairing mounted on a truck is linearly proportional to the rolling resistance force. Therefore, the negative lifting force on a heavy-duty truck is another important factor in aerodynamic design parameter and should be considered in the design of a drag-reducing device of a tractor-trailer. According to the numerical result obtained from present study, the drag force produced by the model-3 has the smallest of all in all speed ranges and has reasonable downward force. The smaller drag force on model-3 with 2/3h in height may results of smallest thickness of boundary layer generated on the topside of the container and the lowest intensity of turbulent kinetic energy occurs at the rear side of the container.

• 대한토목학회논문집
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• 제33권3호
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• pp.1105-1113
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• 2013

교통안전 측면에서 화물차 관련 교통사고 심각도는 화물차의 차량 중량, 물류수송특성, 후행차량의 시거제약 등과 관련된다. 본 연구는 고속도로 화물차사고의 심각도에 미치는 기상 및 도로 교통요인을 도출함에 그 목적이 있다. 이항 로지스틱 회귀분석을 이용하여 사고심각도의 확률적 증가에 영향을 미치는 요인을 기상별로 비교분석하였다. 분석 결과 속도 단속, 속도 관리전략, 화물차 전용차로 등과 같은 교통류 관리전략이 사고심각도 감소를 위한 대책으로 제안되었다. 본 연구의 결과는 향후 화물차 사고발생 및 사고심각도 감소를 위한 교통 관제 및 운영관련 전략 수립시 유용하게 활용될 수 있을 것으로 판단된다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.231-234
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• 2004

This paper is to research about design and drive system of a switched reluctance motor for a pallet truck application. SRM is suitable for a pulse type source and is researched for home and industrial applications owing to the advance of power electronics technology. An SRM for a pallet truck drive is developed and tested. The drive system has to operate with low voltage and high current. The small size, robustness and high efficiency make it possible to replace with DC motor which is used in a pallet truck conventionally. Test results show that pallet truck with SRM has better drive characteristics than that of the DC motor.