• Journal of Power Electronics
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• v.16 no.4
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• pp.1256-1267
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• 2016

Distributed stray inductance exerts a significant influence on the turn-off voltages of power switching devices. Therefore, the design of low stray inductance bus bars has become an important part of the design of high-power converters. In this study, we first analyze the operational principle and switching transient of a T-type converter. Then, we obtain the commutation circuit, categorize the stray inductance of the circuit, and study the influence of the different types of stray inductance on the turn-off voltages of switching devices. According to the current distribution of the commutation circuit, as well as the conditions for realizing laminated bus bars, we laminate the bus bar of the converter by integrating the practical structure of a capacitor bank and a power module. As a result, the stray inductance of the bus bar is reduced, and the stray inductance in the commutation circuit of the converter is reduced to more than half. Finally, a 10 kVA experimental prototype of a T-type converter is built to verify the effectiveness of the designed laminated bus bar in restraining the turn-off voltage spike of the switching devices in the converter.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.1
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• pp.1-7
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• 2005

This paper describes the system for detecting vehicles in the rear and rear-side that access between sidewalk and bus stopped to city road at day by computer vision-based method. This system informs appearance of vehicles to bus driver and passenger for the safety of a bus passenger getting off. The camera mounted on the top portion of the bus exit door gets the rear and rear-side image of the bus whenever a bus stops at the stop. The system sets search area between bus and sidewalk from this image and detects a vehicle by using change of image and sobel filtering in this area. From a central point of the vehicle detected, we can find out the distance, speed and direction by its location, width and length. It alarms the driver and passengers when it's judged that dangerous situation for the passenger getting off happens. This experiment results in a detection rate more than 87% in driving by bus on the road.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.51-58
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• 2022

This paper proposes new measures to aid the uses of pubic transport buses by visually impaired people. Many visually impaired people have difficulty using public buses, but current guidance systems and braille blocks are not useful enough, according to a national survey(2017). In this paper, we develop a system with three functions that help to increase the bus accessibility and mobility of visually impaired people: (1)bus reservation using smart phone applications, (2)arrival notification, and (3)wireless bus stop button using Beacon. Experiments have confirmed that our system supports bus reservation, boarding and getting off the bus efficiently.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.105-116
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• 2008

Today's System-on-a-Chip (SoC) is designed with reusable IP cores to meet short time-to-market requirements. However, the increasing cost of testing becomes a big burden in manufacturing a highly integrated SoC. In this paper, we propose an efficient test access mechanism that exploits an on/off-chip bus bridge for the Advanced High-performance Bus (AHB) and Peripheral Component Interconnect (PCI) bus. The test application time is considerably reduced by providing dedicated test stimuli input paths and response output paths, and by excluding the bus direction tumaround delays. Experimental results show that area overhead and testing times are considerably reduced in both functional and structural test modes. The proposed technique can be a lied to the other types of on/off-chip bus bridges.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.9
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• pp.1081-1087
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• 1999

Load Flow calulation methods can usually be divided into Gauss-Seidel method, Newton-Raphson method and decoupled method. Load flow calculation is a basic on-line or off-line process for power system planning. operation, control and state analysis. These days Newton-Raphson method is mainly used since it shows remarkable convergence characteristics. It, however, needs considerable calculation time in construction and calculation of inverse Jacobian matrix. In addition to that, Newton-Raphson method tends to fail to converge when system loading is heavy and system has a large R/X ratio. In this paper, matrix equation is used to make algebraic expression and then to slove load flow equation and to modify above defects. And it preserve P-Q bus part of Jacobian matrix to shorten computing time. Application of mentioned algorithm to 14 bus, 39 bus, 118 bus systems led to identical results and the same numbers of iteration obtained by Newton-Raphson method. The effect of computing time reduction showed about 28% , 30% , at each case of 39 bus, 118 bus system.

• Smart Media Journal
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• v.11 no.3
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• pp.90-101
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• 2022

Buses are a popular means of transportation. As such, thorough preparation is needed for passenger safety management. However, the safety system is insufficient because there are accidents such as a death accident occurred when the bus departed without recognizing the elderly approaching to get on in 2018. There is a safety system that prevents pinching accidents through sensors on the back door stairs, but such a system does not prevent accidents that occur in the process of getting on and off like the above accident. If it is possible to predict the intention of bus passengers to get on and off, it will help to develop a safety system to prevent such accidents. However, studies predicting the intention of passengers to get on and off are insufficient. Therefore, in this paper, we propose a 1×1 CNN3D-based getting on and off intention prediction model using skeleton keypoints of passengers extracted from the camera image attached to the bus through UDP-Pose. The proposed model shows approximately 1~2% higher accuracy than the RNN and LSTM models in predicting passenger's getting on and off intentions.

• Journal of IKEEE
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• v.23 no.4
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• pp.1469-1472
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• 2019

CAN bus in automotive applications does not assign node addresses. When a node is hacked and it transmits malicious data frame, it is difficult to resolve which node is hacked. However, this CAN bus internal attack seriously threatens the safety of a car, so a prompt counterattack is necessary in the CAN bus physical layer. This paper proposes a counterattack method against malicious CAN bus internal attack. When a malicious data frame is detected, an intrusion detection system in the CAN bus increases the error counter of the malicious node. Then, the malicious node is off from the bus when its error counter exceeds its limit. A CAN controller with the proposed method is implemented in Verilog HDL, and the proposed method is proved to counterattack against malicious CAN bus internal attack.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.12
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• pp.675-682
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• 2000

When a system is composed of multi-boards, an efficient bus arbitration method for the data transfer bus must be provided for guaranteeing proper operations. In this paper, a new test methodology is developed which is used for testing on-line bus arbitration. In the new test methodology, events that are occurred during bus arbitration are defined, and expected signals during fault-free bus arbitration are compared with the signals captured during on-line bus arbitration using boundary-scan cells. For this, a new test architecture is proposed which is efficient for the maintenance and the repair of multi-board systems. In addition, the new methodology can be used with off-line interconnect test using boundary-scan.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.125-134
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• 2010

It is occurred bus arrival time errors when a bus arrives at a bus stop because of a variety of traffic condition such as traffic signal cycle, the time to get on and off a bus, a bus-only lane and so on. In this paper, bus delay time which is occurred as the result of traffic condition was estimated with Markov Chain process and bus arrival time at each bus stop was predicted with it. As the result of the study, it is confirmed to improve accuracy than the method of bus arrival time prediction with existing method (weighed moving average method) in case predicting bus arrival time using 7 by 7 and 9 by 9 matrixes.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.873-882
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• 2017

Smart cards are currently used in about 150 locales, including the metropolitan ares, and are utilized as a policy base for various public areas, including public transportation, bus fares, and public transportation requirements. However, excluding the metropolitan area and some metropolitan areas, there are many areas where the existing BIS data was unable to match station information on the data and Smart cards itself are not available on the bus stop information by the line. The purpose of this research was to produce bus stop information generated by the bus stop based on the bus route, and the actual stop information generated by the model presented in the study was derived by matching the actual station information.