Traffic accidents that occur while driving a car are inevitable, and the characteristics of the body repair field are that each vehicle accident has the same damage and no same repair conditions. Therefore, it is difficult to acquire know-how in vehicle body repair simply by theoretical method of textbook, and the repair method must be changed as new materials and new technologies are applied to it. In particular, roof panels are not frequently damaged by traffic accidents, but they are damaged by falling objects from the roof of a building or the opposite lane, resulting in roof bending and vehicle repair using dent repair to minimize VOC and reduce costs. In this study, the optimal maintenance method is proposed by analyzing the time, cost, and waste generation according to the work method when the degree of damage is large and replacement is required

Considering the features of body repair for automotive body where same damage and repair conditions does not exist in car accident, it is essential to acquire know-how and continuously approach new materials and new technologies on the site of maintenance where the theoretical instruction of textbook cannot react accurately minute by minute. Especially, in case of car repair from unexpected accidents such as body repair or dent repair, it is difficult to satisfy vehicle owners despite their request. Accordingly, this study researched the better maintenance technology to restore to its original state with more improved technology as vehicle owners wish. This study made time to repair reduced by 98% and the cost reduced by 79.6% through the accurate diagnostic technique before repair and maintenance technologies of body crash analysis applying property of high-speed tensile. It also obtains intangible effects including prevention of environmental pollution and maximization of vehicle owners satisfaction.

Recently, halogen lamps for vehicle exterior lamp systems are being replaced by LEDs (Light Emitting Diode) in consideration of miniaturization, power consumption, life, luminance, and eco-friendliness. Due to regulations on the amount of light required, luminance, light uniformity, and glare prevention, it is required to develop a light guide for controlling a light source of an LED lamp for a vehicle. For the development of the light guides, the development of machining technology that can cut micro patterns of hundreds of micrometers scale into surface roughness of tens of nanometers scale must be preceded. In this study, the effect of variations in cutting conditions on surface roughness was analyzed through experiments. The micro patterns was manufactured by cutting into STAVAX material, and the surface of the micro patterns was super-finished using a ball-shaped PCD (polycrystalline diamond) tool without flutes. In experiments, the cutting conditions of the super-finishing process were varied, and the varied cutting conditions were feed rate, radial depth of cut, and spindle speed

In this study, a finite element analysis was used to analyze the stress state and vibration characteristics generated by continuous contact between wheels and rails when driving urban railway vehicles. The rails applied to the analysis were divided into straight and curved shapes, and three-dimensional modeling was performed to analyze the changes in structural characteristics of wheels and rails when driving on straight and curved rails. As a result of the analysis, the stress characteristics were up to 6.5 MPa on a straight rail and 9.81 MPa on a curved rail, and it is believed that this increase in stress will increase noise due to an increase in friction at the interface. The vibration characteristics of the wheels and rails showed similar behavior from the 3rd mode to the 9th mode of the rail to the intrinsic vibration characteristics from the 4th mode to the 6th mode of the wheel.

도서관은 문화 공간으로서 누구나 이용할 수 있고 다양한 분야의 지식과 정보를 제공하여 삶의 질을 높이는 중요한 사회기반 시설 중 하나이다. 현재 한국의 도서관 수는 수요에 비해 공급이 부족한 상황이며, 이를 해결하기 위해 일부 지자체는 차량을 수단으로 이동형 도서 서비스를 제공하는 분관 형태의 이동 도서관을 운영하고 있다. 주로 도서관을 이용하기 어려운 사람들을 대상으로 순회하며 도서관 서비스를 제공하지만, 비효율적인 운행 노선과 균일하지 않은 서비스로 실질적인 효과를 발휘하지 못하고 있다. 따라서 본 연구에서는 성남시 새마을 이동 도서관을 대상으로 순회 경로 현황을 파악하고, 최소 이동 거리로 개선된 이동 도서관 노선을 제시하고자 한다. 더욱 효율적인 운영을 위해 서비스 권역을 나누고, 시간 제약을 결합한 차량경로설정 문제를 사용하여 도서 서비스의 이용 격차를 줄인 새로운 운행 노선을 구축하였다. 본 연구는 이동 도서관의 효과적인 노선 운영에 대한 기초적인 자료로 활용될 수 있다는 점에서 의의가 있다. 향후 이동 도서관 뿐만 아니라 이동형 공공 서비스를 위한 유용하고 현실적인 가이드라인으로 활용될 수 있을 것이다.

목적 : 본 연구는 조건부 운전면허 중 차량제한(vehicle limit)에 대한 국가별 사례를 비교해보고 자율주행까지 범 위를 확대하여 작업치료사의 역할을 알아보고자 한다. 연구방법 : 조건부 운전면허 중 신체 및 인지능력 보조를 위한 차량의 개조 및 특정 보조기기 부착조건의 차량제 한 제도가 있다. 우리나라의 경우, 신체장애를 기준으로 특정 차량 또는 보조기기 부착을 의무화하고 있다. 이에 반해 영국과 호주는 의학적 진단명에 따른 운전허용 기준을 마련하고, 필요에 따라 작업치료사의 평가와 관련 전문가의 상담을 통해 개인 맞춤형 차량의 개조 및 보조기기를 제공하고 있다. 자율주행시대를 반영한 운전면허 제도 개선 움직임이 진행되고 있다. 자율주행의 시대에 운전자는 새로운 기기의 조작 및 상황대처 능력 등 인지 적 능력이 강조될 것이며, 신체 장애인의 승하차에 대한 중재 필요성은 여전히 요구될 것이다. 결론 : 본 연구를 통해 차량제한에 있어서의 호주, 영국과의 비교를 통해 작업치료사의 역할에 대한 이해를 바탕 으로 작업치료사의 업무범위와 역할 확대에 관한 논의가 이루어 질 것으로 기대된다.

Due to the issue of the sustainability in transportation area, the number of electric vehicles has significantly increased. Most automakers have decided or planned to manufacture the electric vehicles rather than carbon fueled vehicles. However, there are still some problems to figure out for the electric vehicles such as long charging time, driving ranges, supply of charging stations. Since the speed of growing the number of electric vehicles is faster than that of the number of charging stations, there are lack of supplies of charging stations for electric vehicles and imbalances of the location of the charging stations. Thus, the location problem of charging stations is one of important issues for the electric vehicles. Studies have conducted to find the optimal locations for the charging stations. Most studies have formulated the problem with deterministic or hierarchical models. In this paper, we have investigated the fluctuations of locations and the capacity of charging stations. We proposed a mathematical model for the location problem of charging stations with the vehicle routing problem. Numerical examples provide the strategy for the location routing problems of the electric vehicles.

Transportation in urban area has been getting hard to fulfill the demand on time. There are various uncertainties and obstacles related with road conditions, traffic congestions, and accidents to interrupt the on-time deliveries. With this situation, the last mile logistics has been a keen issue for researchers and practitioners to find the best strategy of the problem. A way to resolve the problem is to use parcel lockers. Parcel locker is a storage that customers can pick up their products. Transportation vehicles deliver the products to parcel lockers instead of all customer sites. Using the parcel lockers, the total delivery costs can be reduced. However, the inconvenience of customer has to increase. Thus, we have to optimal solution to balance between the total delivery costs and customers' inconvenience. This paper formulates a mathematical model to find the optimal solution for the vehicle routing problem and the location problem of parcel lockers. Experimental results provide the viability to find optimal strategy for the routing problem as well as the location problem.

PURPOSES : The "Super-Bus Rapid Transit" (S-BRT) standard guidelines recommend installing physical facilities to separate bus lanes, so as to remove possible conflicts with other traffic when using an existing road as an S-BRT route. Based on a collision simulation, we reviewed the protective performance and installation method of a low-profile barrier, i.e., one that does not occupy much of the width of the road as a physical facility and does not obstruct the driver's vision. METHODS : The LS-DYNA collision analysis software was used to model the low-profile barrier, and a small car collision simulation was performed with two different installation methods and by changing the collision speeds of the vehicle. The installation methods were divided into a fixed installation method based on on-site construction and a precast method, and collision speeds of 80 and 100 km/h were applied. The weight of the crash vehicle was 1.3 tons, and the segment lengths of the low-profile barriers were 2.5 and 4.0 m, respectively. The lowprofile barriers were modeled as precast concrete blocks, and the collision simulation for a fixed concrete barrier was performed by fixing the nodes at the bottom of the low-profile barrier. The low-profile barrier comprised a square cross-section reinforced concrete structure, and the segments were connected by connecting steel pipes with varying diameters to wire ropes. RESULTS : From comparing and analyzing the small car collision simulations for the changes in collision speeds and installation methods of the low-profile barrier, a significant difference was found in the theoretical head impact velocity (THIV) and acceleration severity index(ASI) for the 2.5-m barrier at a collision speed of 80 km/h. However, the differences in the installation method were not significant for the 4.0-m barrier. The occupant safety index with a collision speed of 80 km/h was calculated to be below the limit regardless of the installation method, and the length of the segment satisfied the occupant protection performance. At a collision speed of 100 km/h, when the segment length of the 2.5-m barrier was fixed, the THIV value exceeded the limit value; thus, the occupant protection performance was not satisfied, and the occupant safety index differed depending on the installation method. The maximum rotation angle of the vehicle, which reflects the behavior of the vehicle after the collision, also varied depending on the installation method, and was generally small in the case of precast concrete. CONCLUSIONS : Low-profile barriers can be installed using a fixed or precast method, but as a result of the simulation, the precast movable barrier shows better results in terms of passenger safety. Therefore, it would be advantageous to secure protection performance by installing a low-profile barrier with the precast method for increased safety in high-speed vehicle collisions.

PURPOSES : The purpose of this study was to investigate the characteristics of concrete pavement behaviors and performance depending on the group-axle types of heavy vehicles, such as single-, tandem-, and tridem-axles. METHODS : The concrete pavement performance indices (such as the rate of fatigue cracking and surface smoothness) according to the different group-axle types of heavy vehicles were predicted using the Korean pavement design program. It was assumed that the load magnitude was the same for each axle, and that the equivalent single-axle traffic volumes were the same for the different group-axle types. The concrete pavement stresses depending on the different group-axle types of heavy vehicles were also analyzed using a finite element analysis program. RESULTS : Based on the design criteria, the concrete pavement performance was the highest under tandem-axle traffic and lowest under single-axle traffic, although the difference in performance was not significant. Based on the structural analysis criteria, the tensile stress of the concrete pavement was the largest under the single-axle load and smallest under the tridem-axle load when the load magnitude of each axle was the same. CONCLUSIONS : Based on the results obtained from considering both the design and analysis criteria, it was concluded that the groupaxle types (such as the tandem- and tridem-axle configurations of heavy vehicles) would not increase the stress or decrease the performance of concrete pavements relative to the single-axle configuration.

PURPOSES : The objective of this study was to evaluate the effectiveness of dust removal by dust removal vehicles by the measuring dust load and PM10 concentrations on the sidewalks of block pavements. METHODS : Field experiments were conducted to determine a dust removal method suitable for the sidewalk conditions, as identified through a literature review. Data collection was followed by the evaluation of the sidewalk dust load with removal vehicles and analysis of the PM10 content within a service road. Moreover, an economic analysis was conducted based on the social costs of dust reduction. RESULTS : When cleaning a sidewalk block by spraying water, the contaminants in small gaps in the block pavement could be reduced, providing a potential solution to void clogging. The dust on the surface of the sidewalk was suspended from a paved road with a high level of traffic volume. Using sidewalk dust removal vehicles with sweeping, spraying water, and inhalation reduced the dust load and PM10 contents by more than 2 and 0.07g/m2, respectively. CONCLUSIONS : According to the economic analysis of the development of dust removal vehicles for sidewalks, the cost-benefit analysis method shows an input effect of 0.4, but if the reduction amount of fine particles such as PM2.5, further experiments are necessary to address the atmospheric fine dust concentrations resulting from cleaning sidewalk block pavements.

An automated material handling system (AMHS) has been emerging as an important factor in the semiconductor wafer manufacturing industry. In general, an automated guided vehicle (AGV) in the Fab’s AMHS travels hundreds of miles on guided paths to transport a lot through hundreds of operations. The AMHS aims to transfer wafers while ensuring a short delivery time and high operational reliability. Many linear and analytic approaches have evaluated and improved the performance of the AMHS under a deterministic environment. However, the analytic approaches cannot consider a non-linear, non-convex, and black-box performance measurement of the AMHS owing to the AMHS’s complexity and uncertainty. Unexpected vehicle congestion increases the delivery time and deteriorates the Fab’s production efficiency. In this study, we propose a Q-Learning based dynamic routing algorithm considering vehicle congestion to reduce the delivery time. The proposed algorithm captures time-variant vehicle traffic and decreases vehicle congestion. Through simulation experiments, we confirm that the proposed algorithm finds an efficient path for the vehicles compared to benchmark algorithms with a reduced mean and decreased standard deviation of the delivery time in the Fab’s AMHS.

PURPOSES : A methodology for estimating micro-emission factors using vehicle trajectory data collected from navigation and DTG devices and basic emission factors for each vehicle type of the MOtor Vehicle Emission Simulator (MOVES) is presented. The methodology can calculate micro-emissions based on only the traffic volume and average speed for each vehicle type. METHODS : Cluster analysis was performed by accumulating the trajectories of individual vehicles on a specific road section into speed groups in which vehicles drove with the same range of average speed. Then, the micro-emission factors were estimated for each speed group. RESULTS : Using the vehicle trajectory data revealed that the emissions calculated from micro-emission factors estimated by the proposed methodology were similar to the sum of the emissions calculated from the vehicle trajectories for each vehicle. CONCLUSIONS : The micro-emission factor database for each road type and vehicle type proposed in this study should be useful for estimating vehicle emissions on the road. The proposed method can calculate emissions in the same way as the macroscopic analysis method, using the traffic volume, average speed, and link length.

PURPOSES : The purpose of this study was to develop techniques for forecasting black ice using historical pavement temperature data collected by patrol cars and concurrent atmospheric data provided by the Korea Meteorological Administration. METHODS : To generate baseline data, the physical principle that ice forms when the pavement temperature is negative and lower than the dew-point temperature was exploited. To forecast frost-induced black ice, deep-learning algorithms were created using air, pavement, and dew point temperatures, as well as humidity, wind speed, and the z-value of the historical pavement temperature of the target segment. RESULTS : The suggested forecasting models were evaluated against baseline data generated by the above-mentioned physical principle using pavement temperature and atmospheric data gathered on a national highway in the vicinity of Young-dong in the Chungcheongbukdo province. The accuracies of the forecasting models for the bridge and roadway segments were 94% and 90%, respectively, indicating satisfactory results. CONCLUSIONS : Preventive anti-icing maintenance activities, such as applying anti-icing chemicals or activating road heating systems before roadways are covered with ice (frost), could be possible with the suggested methodologies. As a result, traffic safety on winter roads, especially at night, could be enhanced.