• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.360-366
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• 2017

In commercial vehicles such as frame-based mid-size trucks, it is easy to reduce vibration caused by driveline with the cab mount system. There are no critical driveline vibration problems associated with these vehicles up to now. However, in the case of a similar grade of monocoque type mini-bus, there are no effective vibration isolation components such as a cab mount. Vibration caused by driveline is quite a complex problem to understand in terms of which part governs the phenomenon and how the problem can be solved. Thus, we have to manage the design factor about the driveline and mount system strictly at the early stage of vehicle development. Low frequency vibration caused by the driveline system is investigated in this study. We created the CAE driveline model and analyze low frequency vibration. Then contribution analysis about each design factor of driveline and mount system is performed. Finally, we can obtain the optimized design factor for a driveline system of a mini-bus, which is verified by the vehicle test results.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.10
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• pp.1149-1156
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• 2012

In this study, we proposed the most efficient driving posture based on the analysis of quantitative muscular strength and fatigue degree according to posture. Since driving include complicated actions required by a variety of ability and cause by extremes concentration or strain, drivers tend to feel tired easily. However, drivers can't recognize the fatigue degree by themselves. Moreover, the method for measuring the quantitative fatigue degree exactly is quite difficult to be secured. 9 professional bus drivers were participated. We analyzed the quantitative legs' muscular strength when operating each pedal. And then we also analyzed the muscular strength and muscular fatigue degree according to driving pattern during bus driving. Therefore, we suggested the most efficient driving posture.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.1-13
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• 2009

Although enormous data have been collected in major cities (Korea) by APTS(Advanced Public Transit Systems), most of studies related to bus schedule management evaluation have confined to headway adherence and on-time performance. Therefore, bus operation management have been very lack of using APTS data. This study uses coefficient of correlation to evaluate bus company's schedule management level. However, direct application of coefficient of correlation has inequitable problem because of many limitation(number of vehicle, headway, etc). and so variable calibration method was developed and applied to cope with these problems. Thus, demand-elastic management evaluation index was developed. For verifying the equity of developed index, it is applied to Seoul bus routes. It is expected for the developed index to contribute into the demand-elastic management of bus schedule.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3067-3069
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• 1999

In this paper, A bit processor for controlling sequence logic was implemented, using a FPGA. This processor consists of program memory interface. I/O interface, parts for instruction fetch and decode, registers, ALU, program counter and etc. This FPGA is able to execute sequence instruction during program fetch cycle, because of divided bus system, program bus and data bus. Also this bit processor has instructions set that 16bit or 32bit fixed width, so instruction decoding time and data memory interface time was reduced. This FPGA was synthesized by pASIC 2 SpDE and Synplify-Lite synthesis tool of Quick Logic company. The final simulation for worst cases was successfully performed under a Verilog HDL simulation environment. And the FPGA programmed for an 84 pin PLCC package. Finally, the benchmark was performed to prove that Our FPGA has better performance than DSP(TMS320C32-40MHz) for the sequence logic control of PLC.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.19-20
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• 2015

Since 2013, Seoul Metropolitan Government (SMG) has introduced big data initiatively in administration and put into practices in transportation, safety, welfare in order to overcome limited resources and conflicting interests. For establishing a new midnight bus service, SMG prepared optimized midnight bus routes by analyzing big data from mobile phone Call Data Record (CDR) through collaboration with a telecommunication company. Despite of limited budget and resources, newly identified routes can cover over 42% of the citizen with 9 routes and less than 1% of buses compare with day time operation. In addition to solve transportation problem, SMG utilizes big data to resolve location selection problem for choosing new facility locations such as life double cropping centers and senior citizen leisure centers. As results, SMG demonstrates big data as a good tool to make policies and to build smarter city by overcome space-time limitation of resources, mediation of conflicts, and maximizes benefit of the citizen.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.135-142
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• 2010

The convenient techniques for predicting the bus arrival time have used the data obtained from the buses belong to the same company only. Consequently, the conventional techniques have often failed to predict the bus arrival time at the downstream bus stops due to the lack of the data during congestion time period. The primary objective of this study is to overcome the weakness of the conventional techniques. The estimation model developed based on the data obtained from Bus Information System(BIS) and Bus management System(BMS). The proposed model predicts the bus arrival time at bus stops by using the data of all buses travelling same roadway section during the same time period. In the tests, the proposed model had a good accuracy of predicting the bus arrival time at the bus stops in terms of statistical measurements (e.g., root mean square error). Overall, the empirical results were very encouraging: the model maintains a prediction job during the morning and evening peak periods and delivers excellent results for the severely congested roadways that are of the most practical interest.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.2
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• pp.1-11
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• 2019

The accident of mass transit such as a bus could draw the large casualties and this induces social and economic losses. Recently, severe bus accidents caused by tiredness and inattention of bus drivers occurred and those lead to growing interest in bus accidents and the drivers' work environment. Therefore, this study analyzes the accident based on the work environment of bus drivers and route-bus categories. For the research, this study collected digital tachograph data and the bus company information for 271 domestic bus companies in 2017 and used ANOVA test and chi-square test as statistical methodologies. As a result, we figured out there are statistically significant differences in the accident according to the working environments. Especially, the present study confirmed the intracity bus with working every other day has the most frequent accidents. We expect that the results of this study be used as foundations for the improvement of working conditions to reduce route-bus accidents in the future.

• Journal of Auto-vehicle Safety Association
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• v.13 no.3
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• pp.69-77
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• 2021

Although accident data from the National Police Agency and insurance companies do not know the vehicle safety, the damage level information can be obtained from the data managed by the bus credit association or the bus company itself. So the accident severity was analyzed based on the side impact accidents using accident repair cost. K-means clustering analysis separated the cost of accident repair into 'minor', 'moderate', 'severe', and 'very severe'. In addition, the side impact accident severity was analyzed by using an ordered logit model. As a result, it is appeared that the longer the repair period, the greater the impact on the severity of the side impact accident. Also, it is appeared that the higher the number of collision points, the greater the impact on the severity of the side impact accident. In addition, oblique collisions of the angle of impact were derived to affect the severity of the accident less than right angle collisions. Finally, the absence of opponent vehicle and large commercial vehicles involved accidents were shown to have less impact on the side impact accident severity than passenger cars.

• Korean Journal of Computational Design and Engineering
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• v.16 no.1
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• pp.61-72
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• 2011

As the customer's needs for diverse colors, the process of bus painting shop is becoming more and more complex. In particular, frequent changes of paint colors in each spray process require the cleaning of the painting nozzles and setting them up for the new paints, which results in increased time and cost and reduced production. This also increases environmental influences. This paper proposes, as a solution to this issue, the use of color selection field (CSF). CSF is physically a system of conveyors that are used to rearrange objects in a flow line. CSF is proposed, in this paper, to be introduced right before the spray process so that buses are better grouped according to their desired colors. Various parameters of the CSF, such as the number of conveyors and algorithms to determine the rearranged sequence of buses, have been determined by running simulations using the digital manufacturing technology, and investigating the simulation results. As an outcome of the proposed solution, the CSF system is expected to reduce approximately 30% of the nozzle cleaning cost for a Korean motor company case, which will not only benefit the company economically, but will also benefit the environment.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.146-148
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• 2005

The number of wind generation installations are growing substantially in Jeju, Korea. Many of these installations are significant in size and directly connected to the distribution system. In these distributed applications, it is not uncommon for the turbines to be connected near the end of a long rural distribution feeder from which end-users are served. Therefore, utility grid interconnection standards for interconnecting non-utility distributed generation systems are essential to both power system company and generation company. In this paper, it is investigated the power quality of Sungsan substation bus connected to Hangwon wind power generation farm.