• Journal of Korean Society of Transportation
• /
• v.31 no.4
• /
• pp.67-75
• /
• 2013

The main objective of the research is to analyse the efficiency of bus route operation system which is comprised of Individual Operation System and Joint Operation System. While the reformation of bus route operation system has been usually considered as a service upgrade strategy for inner-city bus operation, it is comparatively difficult to have background information for policy establishment due to shortage of analytical research output. This study adopts Data Envelopment Analysis technique to estimate efficiency of 101 bus routes in Ulsan Metropolitan City which operates two types of operation systems at the same time as of 2009. The analysis results tells that the reason of inefficiency lies on pure technical factor for J.O.G., and scale factor for I.O.G.. It is also confirmed that there is bus route which inefficiently operated in I.O.G and city government needs to prepare the specific plan to upgrade pure technique efficiency before reformation of bus route operation system for successful installation.

• International Journal of Highway Engineering
• /
• v.15 no.3
• /
• pp.159-167
• /
• 2013

PURPOSES: The purpose of this study is to develop an effectiveness analysis method of exclusive median bus lanes, which is necessary in order to improve operation efficiency of exclusive median bus lanes. METHODS : The operation characteristics of "signalized intersection including exclusive median bus lanes" and "normal signalized intersection" were investigated and the existing capacity analysis method was also reviewed to analyze the effectiveness of exclusive median bus lanes. Delay reduction of passengers using exclusive median bus lanes which can be considered as the benefit of exclusive median bus lanes and the number of people in buses were included in the proposed effectiveness analysis method. RESULTS : It was found that the proposed method expresses properly the effectiveness of exclusive median bus lanes through performing sensitivity analysis and analyzing with the real data of the number of people in buses and passenger cars. It was also found that the proposed method demonstrates the effectiveness that measure of effectiveness of signalized intersections is changed to "sec/person". CONCLUSIONS : It was concluded that the method is a proper effectiveness analysis method because it can reflect the benefit of passengers in buses.

• Journal of the Korean Society of Safety
• /
• v.27 no.3
• /
• pp.153-160
• /
• 2012

Various social problems such as traffic congestion, car accidents and environmental problems(air pollution, noises etc.) have been happening in the Seoul metropolitan area that has the car oriented traffic system providing cars continuously. Along with this, the financial burden caused by current oil price anxiety made paradigm shift from caroriented to public transportation-oriented. Its typical example is an arterial branch bus system changing(bus lane through the center of main road) started in Seoul in July, 2004. But study on safety analysis of bus lane and characteristic of accidents are not sufficient enough to now. The bus lanes are expanded to provide roads for better traffic operation and accidents between buses and pedestrians or ordinary vehicles are considered main problems. This study divided each bus route of median bus lane(bus-only lane through the center of main roads) and bus lane at roadside by intersection and collected and analysed data about influence variables of bus accidents chosen in each section. We constructed a logistic model using collected data. As a result, bus lane at roadside are used by both buses and other kinds of vehicles differently from median bus lane and showed such characteristic in accident influence. Therefore access management to factors causing conflict and improvement of operation management are required. In case of median bus lane, the more buses moving general vehicle lane and traffic volume of section were, the more accidents happened. In case that stop line of center lane is not backward, view blocking of vehicles turning left caused accidents.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.6 no.3
• /
• pp.12-23
• /
• 2007

The purpose of this studγ if to understand problem of present bus scheduling system and to develop optimal bus scheduling model which improve bus passenger's degree of satisfaction(DOS) and bus company's operation efficiency at the same time. This study developed optimal bus scheduling model, which reflected bus passenger's degree of satisfaction(DOS), applied to existing model that summery of bus operation cost($C_o$), passenger queuing time cost($C_{pw}$) and passenger travel time cost($C_{pl}$). And optimal bus scheduling model which developed in this study is optimized that using LINGO program based on linear program. Also by using the general case in Busan, compare total cost of present bus scheduling system and existing scheduling model with total cost of optimal bus scheduling model which reflected bus passenger's degree of satisfaction(DOS).

• Journal of Digital Convergence
• /
• v.8 no.4
• /
• pp.19-33
• /
• 2010

As one of the most traffic devices, bus has played a great role in Korea for the last years. However, a great many peoples in big cities have continually decreased with the increase of private car ownership. It causes lower quality of bus service and unstability of operation in many bus companies. In the several local government, the operation system of bus was changed to Bus Quasi-Public Operating System. The aim of this study is to assess the effects and to suggest improvement strategies of Bus QPOS. According to the results of the analysis, Bus QPOS has brought various positive effects, but it has occurred negative effects, especially a much increase of government subsidies to bus company. To resolve a negative effects, government should examine the whole condition of bus operations. This study suggests strategies to improve Bus QPOS, which is including transparency of management, fair assessment system, standard cost system for bus operations.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.6
• /
• pp.188-198
• /
• 2013

In order to increase its performance, NAND flash memory-based storage is composed of data buses that are shared by a number of flash memories and uses a parallel technique that can carry out multiple flash memory operations simultaneously. Since the storage performance is strongly influenced by the performance of each data bus, it is important to improve the utilization of the bus by ensuring effective scheduling of operations by the storage controller. However, this is difficult because of dynamic changes in buses due to the unique characteristics of each operation with different timing, cost, and usage by each bus. Furthermore, the scheduling technique for increasing bus utilization may cause unanticipated operation delay and wastage of storage resource. In this study, we suggest various dynamic operation scheduling techniques that consider data bus performance and storage resource efficiency. The proposed techniques divide each operation into three different stages and schedule each stage depending on the characteristics of the operation and the dynamic status of the data bus. We applied the suggested techniques to the controller and verified them on the FPGA platform, and found that program operation decreased by 1.9% in comparison to that achieved by a static scheduling technique, and bus utilization and throughput was approximately 4-7% and 4-19% higher, respectively.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.5
• /
• pp.102-107
• /
• 2014

Because of high oil prices and emission gas problems, many governments tighten regulation of fuel economy and emission gas. For Passenger car, there are many researches for plug-in hybrid electric vehicles and they are being manufactured. On the other hand, there are few researches for plug-in hybrid electric bus that is heavy commercial vehicle. In this study, analysis of fuel economy for series plug-in hybrid electric bus according to engine operation strategy based on simulation is conducted. Forward simulator is developed using Autonomie. Engine operation strategies consist on constant engine operation strategy and engine on/off operation strategy. Considering the engine operation strategy, results of vehicle speed, engine operating points and fuel economy are obtained and analyzed. As a result, engine on/off operation strategy has more advantage than constant engine operation strategy in terms of fuel economy.

• Journal of Korean Society of Transportation
• /
• v.31 no.4
• /
• pp.18-31
• /
• 2013

The operational purpose of exclusive bus lanes is to ease traffic congestion through the increase of person-carrying capacity on arterial roads. It is necessary to study on the route suitability for exclusive bus lanes because their operation may worsen traffic congestion due to the misuse of general purpose lane for an exclusive bus lane. This research quantifies the route suitability for exclusive bus lanes in Kwangju-city utilizing 7 indexes such as bus traffic volume, number of bus routes, traffic volume per lane, number of lane, number of intersection, number of streets, rate of curvature for the exclusive bus lane, recognizing the problem that the current installation standard of exclusive bus lanes is only limited to the bus traffic volume and the number of bus passengers. In addition, this research analyzes the operational efficiency for exclusive bus lanes, which is currently operated and their optimal operation hours.

• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.458-460
• /
• 2001

This paper described the unbalanced voltage on the tertiary bus of a single Phase auto transformer in the case of parallel operation with different manufacturer at each Phase. The unbalanced capacitances between primary to secondary winding, secondary to tertiary winding and primary to tertiary winding makes unbalanced bus voltage in the tertiary bus side. The unbalanced voltage let the surge arrester to operate in the power frequency range, and it causes the arrester to burn out. The failure of the arrester at one phase makes line to ground fault, which lead to the surge arrester failure of the other two phase on the tertiary bus.

• Journal of the Korea Society for Simulation
• /
• v.12 no.4
• /
• pp.95-102
• /
• 2003

Stream servers are for supplying multimedia stream data to users through the internet such as movies and music without discontinuation. A typical stream server is designed roughly by considering the characteristics of stream services and by employing processors, memory, PCI bus, Ethernet, TOE and disks. This study focuses on deciding the priority for using resources such as PCI bus, buffer memory and TOE buffer, which have limited capacities in a typical stream server. When the priorities for using limited resources are not given properly, the stream servers may not even function as originally designed. The simulation study shows that the top priority for using PCI bus for normal streaming services should be given to the operation that sends data from buffer memory to TOE buffer. Giving priority for using PCI bus to other operation such as sending data from disks to memory results in a deadlock phenomenon.