• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.538-545
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• 2001

In this paper a gearless drive system using a permanent-maget synchronous motor for high speed elevators is addressed. The application of permanent magnet synchronous motor to an elevator traction machine enables several improvements including higher efficiency better ride comfort smaller size and lighter weight and so on A PWM boost converter has been also adopted so that DC-link voltage regulation bi-directional power flow and controllable power factor with reduced input current harmonics are possible. To increase the reliability and performance of overall control system the unified control board which can include the car and group controller as well as PWN converter/inverter controller has been designed based on a DSP TMS320VV33. In addition the dynamic load simulator system has been developed so that the drive system of high speed elevator can be tested and evaluated without and limitation on ride distance. Some experimental results are given to verify the effectiveness of the developed system.

• Journal of Korean Society of Transportation
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• v.29 no.6
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• pp.25-37
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• 2011

This research aimed to investigate whether commercial drivers' situation awareness ability is related to their frequency and magnitude of caused accidents and penalty points. For the purpose of measuring drivers' situation perception and interpretation capacities, two tests named 'situation awareness test' and 'hazard perception test' were developed. The tests were based on the data from 299 commercial drivers (test drivers) using a driving simulator. The outcome of drivers' performance on situation awareness and hazard perception tests was designed to be categorized into 5 grades, classifying the best as grade 1 and the worst as grade 5. As the result, low grades on situation awareness test had positive relationship with accumulated penalty points, frequency of accidents and safety index. Grades on hazard perception test were also positively correlated with accident frequency and safety indices. This suggests situation awareness ability of commercial drivers is significantly related to traffic violations and accident causing tendencies.

• Journal of Biomedical Engineering Research
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• v.38 no.4
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• pp.197-204
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• 2017

The aim of this study was to evaluate driving performance of normal subjects for controlling the steering wheel by using foot operated steering devices in the driving simulator. Many people with complete bilateral loss or loss of use of upper limbs but with normal lower limbs are frequently left without use and/ or control of their hands, arms, or the upper extremities of their bodies. As a result, persons disabled in this manner have problems in operation an automobile because they cannot grasp and manipulate a conventional steering wheel. Therefore, if foot operated steering devices are used for controlling the vehicle on in people with disabilities, the disabled people could improve their community mobility by driving a car safely. Ten normal subjects were involved in this research to evaluate steering performance by using three types of steering devices(conventional steering wheel, pedal type foot steering, circular type foot steering) in driving simulator. STISim Drive 3 program was used for testing the driving performance in two road scenarios: straight road and curved road at low and high speed of vehicle (40 km/h and 80 km/h). This study used two-way ANOVA to compare the influences of two factors(type of foot steering device and road scenario) in the three dependent variables of steering performance(standard deviation of lateral position, the lateral position of vehicle and the number of line crossing). The average values of the three dependent variables(standard deviation of lateral position, lateral position and the number of line crossing) of driving performance were significantly smaller for conventional steering wheel or pedal type foot steering than circular type foot steering.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.1
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• pp.26-33
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• 2009

The directions of the road are divided into two, the right-hand side and left-hand side of the road, by the convention and specific native method in the world. This paper deals with the characteristics and behaviors of drivers who are accustomed to driving on right-hand side of the road, drive with a handle on the left-hand side, and comparing with left-hand side drivers. The driver's eye movements were measured by eye camera and questionnaires were used for measuring subjective evaluation such as driving mental workload. The experimental results indicated even if the experts who had much experience on right-hand side driving, they had lower driving skill than novice driver, accustomed to driving on left-hand side. In terms of mental workload, MCH rating scale and MNASA-TLX, the right-hand side drivers were in lower stress condition than the left-hand side drivers because of having much driving experience. However, they conducted a few mistakes by confusing the position of turn signal and windshield wiper because of their driving habit or traits and it lead to operation mistakes. These results can be applied effectively to develop the driving support information with changed environments.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1043-1048
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• 2017

Since year 2016, in Korea, the police department started to use drones to patrol violated vehicles on the highway area. They monitor vehicle drivers who use side ways on the highway during traffic congested hours of the season, drunken drivers, or violent drivers. They use the 'Spot Mobility' method which floats the drones for 30 minute period. However, this method is inefficient since it requires manually charging batteries, gathering data, and operate drones with many numbers of policeman. Therefore, in this paper, for the efficient patrol in this purpose, I have suggested an effectively manageable network system consists of many drones as the wireless network nodes and with small numbers of policeman in a wide highway area. To accomplish this, the two topologies of effective drone patrol network systems are designed and simulated in OPNET simulator for performance evaluation.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.1
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• pp.25-31
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• 2010

네덜란드 브리젠빈 하폐수처리장 최종방류수의 $NH_4$-N 및 TN(Total Nitrogen)농도를 방류수 수질기준인 각각 4 mg/L와 10 mg/L에 맞추기 위한 최적의 운전조건을 도출하기 위해 다양한 제어시스템이 시뮬레이션 되었다. 본 연구에 사용된 모델은 IWA(International Water Association) 활성슬러지 모델 No.1 (ASM No.1)이었고, GPS-X가 시뮬레이터로 사용되었다. 모델링을 위한 매개변수 민감도 분석결과 ASM No.1의 총 19개 매개변수 중 8개 변수 ($Y_H$, ksh, koh, $b_H$, ${\mu}_a$, $k_{NA}$, kh, ka)가 방류수 수질에 영향을 미치는 것으로 조사되었고 이들 매개변수에 대해 보정을 수행하여 사용하였다. SRT, 호기/무산소기간, 외부탄소원 주입시간 변화에 따른 방류수질 변화를 시뮬레이션하였는데, 호기/무산소 11h/1h인 조건에서 SRT가 20일에서 25일로 증가되면 $NH_4$-N가 5.0 mg/L에서 2.9 mg/L로 감소되었고 호기/무산소 2h/1h의 조건에서는 SRT증가에 따라 $NH_4$-N은 큰 감소를 보이지만, 바이패스되는 유입수량의 감소로 탈질율이 낮아 방류수 TN이 11.1~11.5 mg/L로 예측되는 결과가 도출되었다. 탈질율을 높이기 위한 아세트산 주입은 동일한 양의 아세트산을 무산소 전기간 (1h)동안 균일 주입하는 것 보다는 무산소 초기 15분내에 주입하는 것이 효율적인 것으로 나타났다.

• Journal of the HCI Society of Korea
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• v.14 no.2
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• pp.21-29
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• 2019

Take-over requests in semi-autonomous cars must be handled properly in the case of road obstacles or curved roads in order to avoid accidents. In these situations, situation awareness and appropriate decision making are essential for distracted drivers. This study used a driving simulator to investigate the components of auditory-visual information systems that affect safety, workload, and trust. Auditory information consisted of either voice guidance providing situation awareness for the take-over or a beep sound that only alerted the driver. Visual information consisted of either a screen showing how to maneuver the vehicle or only an icon indicating a take-over situation. By providing auditory information that increased situation awareness and visual information that aided decision making, trust and safety increased, while workload decreased. These results suggest that the levels of situation awareness and decision making ability affect trust, safety, and workload for drivers.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.4
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• pp.31-43
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• 2019

Take-overs occur in autonomous vehicles at levels 3 and 4 based on SAE. For safe take-over, it is necessary to set the time required for diverse drivers to complete take-over in various road conditions. In this study, take-over time and stabilization characteristics were measured to secure safety of take-over in autonomous vehicle. To this end, a virtual driving simulator was used to set up situations similar to those on real expressways. Fifty drivers with various sexes and ages participated in the experiment where changes in traffic volume and geometry were applied to measure change in takeover time and stabilization characteristics according to various road conditions. Experimental results show that the average take-over time was 2.3 seconds and the standard deviation was 0.1 second. As a result of analysis of stabilization characteristics, there was no difference in take-over stabilization time due to the difference of traffic volume, and there was a significant difference by curvature changes.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.523-529
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• 2020

Power distribution management system is essential for the efficient management and operation of power distribution networks. The power distribution system is a system that manages the distribution network based on IT, and has been evolving along with the development of the power industry. The current power distribution system is designed to operate at a relatively low network transmission speed based on the independent operation of the main equipment. However, due to distributed resources such as photovoltaic or energy storage devices, which are rapidly increasing in popularity in recent years, the operation of future distribution environments is becoming more complex, and various information needs to be collected in real time. In this study, the requirements of the next-generation power distribution system were derived to overcome the limitations of the existing power distribution system, and based on this, the communication network system and performance requirements for the distribution system were defined. In order to verify the performance of the designed system, a software-based terminal device simulator was developed because it takes excessive time and cost to introduce a large-scale system such as a power distribution system. Using the simulator, a test environment similar to the actual operation was established, and the number of terminal devices was increased up to 1,000. The proposed system was shown to satisfy the requirements to support the functions of the next-generation power distribution system, recording less than 10 % of the communication network bandwidth.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.7
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• pp.634-642
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• 2004

Unlike actual vehicles, a vehicle driving simulator is limited in kinematic workspace and bounded on dynamic characteristics. So it is difficult to simulate dynamic motions of a multi-body vehicle model. In order to overcome these problems, a washout algorithm which controls the workspace of the simulator within the kinematic limitation is needed. However, a classical washout algorithm contains several problems such as generation of wrong sensation of motions by filters in tilt coordination, requirement of trial and error method in selecting the proper cut-off frequencies, difficulty in returning the simulator to its origin using only high pass filters and etc. This paper proposes a new tilt coordination method as an algorithm which gives more accurate sensations to drivers. In order to reduce time for returning the simulator to its origin, a new washout algorithm that the proposed algorithm selectively onset mode from high pass filters and return mode from error functions is proposed. As a result of this study, the results of the proposed algorithm are compared with the results of classical washout algorithm through the human perception models. Also, the performance of the suggested algorithm is evaluated by using human perception and sensibility of some drivers through experiments.