• Journal of Digital Convergence
• /
• v.15 no.11
• /
• pp.187-197
• /
• 2017

The purpose of this study is to analyze factors that have significant influence on decision making of inland transportation of shippers. The study was conducted in Republic of Korea and Northern areas of China where marine feeder lines are operated, and logistic regression analysis was used as a research method. More than 67% of the domestic shippers who received the questionnaire were found to make inland transportation decisions. As a result, the inland freight and unloading costs had a significant influence on the inland transportation decision of the shippers. On the other hand, in order to attract domestic and overseas shippers to generate profits, it is necessary to establish various infrastructures and incentives for government support to reduce inland transportation costs and freight charges by identifying needs of shippers. In addition, it is necessary to review the factors influencing decision making of inland freight in shippers and port facilities, and ways to create freight should be sought through continuous improvement efforts in these areas. An analysis using various factors which can influence inland transport is needed as a future study.

• Korean Security Journal
• /
• no.10
• /
• pp.387-407
• /
• 2005

Thanks to the developments of IT technologies, such critical infrastructures as fundamental structures of energies, material circulations, monetary circulations, and living necessaries are intertwined as well as mutually dependent. In this respect, the fact that national infrastructures are closely related to IT infrastructures implies not only expected benefits to provide diverse information-based services, but also anticipated costs to bring about new dangers. However, in spite of these threats, traditional researchers have not put enough interests in these indirect danger, which yield the damages in broad areas through paralyzing risk management systems, although they have investigated such direct threats as nuclear accidents, conflagrations, traffic troubles, and gasoline accidents. Considering that the tendency to depend on electricity, so-called electrification, which is caused by automation and informationalization, is intensified in all parts of society, the breakout problem as a factor to inhibit securities in information-oriented society is significant. Thus, the problems of large-scale power blackout should be treated as national crises. Also, preparation systems for large-scale power blackout have to be provided quickly. In this paper, with analyzing various cases of large-scale power blackout and investigation the causes of them, researches on the blackout management systems of Korea are to be present, on the basis of national crisis management states which are comprised of protection (mitigating and preparing), responding, and recovering(rewarding).

• Journal of Korean Society of Transportation
• /
• v.32 no.4
• /
• pp.347-356
• /
• 2014

Passenger cars occupy about 74% among registered vehicles in Korea and the ratio of transportation mode sharing is approximately 60% in the passenger transport part. However, there is no statistics related to travel characteristics of passenger cars, and official statistics are estimated from O/D travel data. Thus, National Transportation DataBase Center in KOTI has attempted to construct various statistical data through Korea Vehicle Use Survey. Based on these data, Analysis of Variance (ANOVA) was conducted to investigate the differences in travel characteristics of each analysis group. As a result, all of the explanatory variables(weekday vs. weekend, metropolitan area vs. non-metropolitan area, male vs. female, commute time vs. other time, routine purpose vs. non-routine purpose) were found to be different across households. In addition, travel distances per trip of weekday, metropolitan area, male, commute time, and non-routine purpose are longer than the opposite variables. Also, the trip distances of small size(1 to 2 persons) households are shorter compared to large size(more than 5 persons) households.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.53-60
• /
• 2020

The bogies of railway vehicles are one of the most critical components for service. Fatigue defects in the bogie can be initiated for various reasons, such as material imperfection, welding defects, and unpredictable and excessive overloads during operation. To prevent the derailment of a railway vehicle, it is necessary to evaluate and detect the defect of a connection weldment between the car body and bogie accurately. The safety of the bogie weldment was checked using an ultrasonic test, and it is necessary to determine the occurrence of defects using a learning method. Recently, studies on deep learning have been performed to identify defects with a high recognition rate with respect to a fine and similar defect. In this paper, the databases of weldment specimens with artificial defects were constructed to detect the defect of a bogie weldment. The ultrasonic inspection using the wedge angle was performed to understand the detection ability of fatigue cracks. In addition, the convolutional neural network was applied to minimize human error during the inspection. The results showed that the defects of connection weldment between the car body and bogie could be classified with more than 99.98% accuracy using CNN, and the effectiveness can be verified in the case of an inspection.

• Journal of Korean Society of Transportation
• /
• v.25 no.3
• /
• pp.65-74
• /
• 2007

Vehicle inspection is a system to help all vehicles function safely through periodic maintenance. Vehicle inspections have been performed since 1962 in Korea by the government in order to reduce traffic accidents due to vehicle defects. Also, vehicle inspections may help protect citizens against uninsured vehicles and illegal vehicle remodeling by discovering and disclosing those vehicles. The prime objective of vehicle inspection is to guarantee all vehicles drive safely on the road by inspecting and fixing items which can affect traffic accidents. In addition, vehicle inspections may help to improve the public order related to vehicle operations and prevent crime through the confirmation of vehicle identity and authentication of ownership. Although there are many benefits of vehicle inspection. there are some negative opinions of the system. In this study, a methodology to analyze the effectiveness of the vehicle inspection system quantitatively in terms of traffic safety was developed. According to the developed methodology. accidents were reduced by 23.735, which is 11% of the total number of accidents in 2005.

• Journal of Korean Society of Transportation
• /
• v.27 no.1
• /
• pp.73-81
• /
• 2009

While various factors in passenger and freight demand analysis affect on destination choice, a key factor, in general. is an attractiveness measure by size variable (e.g., population. employment etc) in destination zone. In order to measure the attractiveness, some empirical studies suggested that disaggregate gravity model are more suitable than aggregate gravity model. This study proposes that truck travelers trip diary data among Korean commodity flow data could be used to estimate the behaviors of incorporating trip departure time, activity duration and attractiveness in destination. As a result, the main findings of size and distance variables coincide with the conventional gravity model having a positive effect of population variable and a negative effect of distance variable. Due to disaggregate gravity modeling, the unique findings of this study reports that small trucks are more likely to choose short distance and early morning, morning peak and afternoon peak departure time choice. On the other hand, large trucks are more likely to choose long distance and night time departure time choice.

• Journal of Korean Society of Transportation
• /
• v.31 no.3
• /
• pp.65-73
• /
• 2013

Exclusive median bus lanes were installed to mitigate congestions on urban traffic networks. However, capacity analysis of signalized intersections having exclusive median bus lanes have not been provided in current capacity analysis process(analyses). This study aims to develop a method of capacity analysis for lane groups consisting of only buses at the signalized intersections having exclusive median bus lanes. Finding basic saturation flow rates for buses is critical since the operational characteristics between automobiles and buses are fairly different. A total of 8 intersections in Seoul were chosen as study sites. Saturation headways, distances between bus-stop and stopline, and grades of each approach were measured at the sites. It was found that the basic saturation headway and the basic saturation flow rate of buses were 3.27 s/veh and 1,100pc/h/ln, respectively. Adjustment factor for upstream bus-stop locations was estimated with 0.50 and 0.75 when the distances between bus-stop and stopline are 20m and 70m, respectively. This study explains that bus saturation flow rates are decreased in half if the bus stop locates within 20 meters from stop lines.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.11
• /
• pp.1437-1443
• /
• 2013

Railways are currently subject to the enforcement of speed limits for each curve as prescribed by the Railway Operating Rules in Korea. However, research is required to determine the maximum speed of trains passing through each curve that allows them to run without the risk of derailment in relation to the speed enhancement of existing railway tracks. In addition, factors affecting the running safety of railway vehicles can be classified into those in terms of vehicle aspects and those in terms of track aspects. This study sought to analyze the running safety of railway vehicles according to changes in the inclination of the rail from among the factors affecting the enhancement of safety against derailment. To increase the speed of trains passing through curves that have high derailment risk, this study also analyzed the running safety of railway vehicles according to the inclination of the rail and changes in running speed while a vehicle passes through each curve section in both the up and the down train line sections between Namsunghyun and Chungdo, which represent the actual conditions of railway tracks.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.12
• /
• pp.5622-5632
• /
• 2011

This paper presents the simulation design and analysis of Integrated Logistics System(ILS) which is operated by using the AGV(Automated Guided Vehicle). To maximize the operation performances of ILS with AGV, many parameters should be considered such as the number, velocity, and dispatching rule of AGV, part types, scheduling, and buffer sizes. We established the design of experiment in a way of Orthogonal Array in order to consider (1)maximizing the throughput; (2)maximizing the vehicle utilization; (3)minimizing the congestion; and (4)maximizing the Automated Storage and Retrieval System(AS/RS) utilization among various critical factors. Furthermore, we performed the optimization by using the simulation-based analysis and Evolution Strategy(ES). As a result, Orthogonal Array which is conducted far fewer than ES significantly saved not only the time but the same outcome when compared after validation test on the result from the two methods. Therefore, this approach ensures the confidence and provides better process for quick analysis by specifying exact experiment outcome even though it provides small number of experiment.

• Smart Media Journal
• /
• v.6 no.3
• /
• pp.89-94
• /
• 2017

The existing geofences provide only context-awareness service for entering or leaving the set region when a user sets a virtual region for his/her PoI(Point of Interest). Applying the mobile-geofence technology to the connected car technology, which is attracting attention as a next generation technology, it is possible to provide application service without additional infrastructure construction cost However, to do this, we need to expand and improve the functions of traditional geofence. In this paper, we propose and implement a flexible mobile-geofence in which the radii of each geofence applied to vehicles is changed according to context-aware in order to support connected cars technology based on the previously studied mobile three-dimensional geofence system. The proposed flexible mobile-geofence shows experimentally that the region of the geofence is changed according to context-aware of itself and its surroundings after applying a flexible decision algorithm by the flexible factor analysis. In the future, we are expected that the flexible mobile-geofence proposed in this paper will be applied not only to connected-cars technology but also to the application technology of V2X(Vehicle to Everything) for safe and efficient vehicle operation.