• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.1
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• pp.76-86
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• 2015

KSLV-II, a new launch vehicle of Korea, requires a new launch complex(LC) for its own and proper launch operations. The new launch complex will be constructed in NARO Space Center neighboring KSLV-I launch complex for maximizing operation efficiency and economic matters. The launch complex consists of three ground support equipments, i.e., mechanical, electrical, and fuel in general. The fuel ground support equipment could be defined as a combination of systems for storage and supply of propellants and gases which are required by a launch vehicle. The compositions, functions and capabilities of fuel ground support equipment are introduced in this paper. In addition, basic design results of flame deflector configurations are included.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.2
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• pp.125-130
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• 2013

According to the law revision of TPMS mounting obligations in Korea, researches about energy harvester which is the alternative of the battery are actively performed by many groups. Because WSN (Wireless Sensor Network) has the proposition of "Install and forget" and the power supplier also has the same performance as the vehicle's lifetime. In this paper, electromagnetic induction type of energy harvester through the relative motion between the rotating wheel and the fixed brake disc is introduced by using the most efficient source as the rotating motion in the view of vehicle's mechanism. The coil on the wheel and the permanent magnet at the brake disc are arranged in several ways. These various arrangements are the number of coil turns are consisted of design variables. By using the orthogonal array to reduce the experimental cost, the optimal composition is verified through the experiment. Finally the validity of the module is considered by measuring the level of storable electrical energy.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.441-444
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• 2008

This paper describes the development of a circularly polarized microstrip antenna, as a part of the Circularly Polarized Synthetic Aperture Radar (CP-SAR) sensor which is currently under developed at the Microwave Remote Sensing Laboratory (MRSL) in Chiba University. CP-SAR is a new type of sensor developed for the purpose of remote sensing. With this sensor, lower-noise data/image will be obtained due to the absence of depolarization problems from propagation encounter in linearly polarized synthetic aperture radar. As well the data/images obtained will be investigated as the Axial Ratio Image (ARI), which is a new data that hopefully will reveal unique various backscattering characteristics. The sensor will be mounted on an Unmanned Aerial Vehicle (UAV) which will be aimed for fundamental research and applications. The microstrip antenna works in the frequency of 1.27 GHz (L-Band). The microstrip antenna utilized the proximity-coupled method of feeding. Initially, the optimization process of the single patch antenna design involving modifying the microstrip line feed to yield a high gain (above 5 dBi) and low return loss (below -10 dB). A minimum of 10 MHz bandwidth is targeted at below 3 dB of Axial Ratio for the circularly polarized antenna. A planar array from the single patch is formed next. Consideration for the array design is the beam radiation pattern in the azimuth and elevation plane which is specified based on the electrical and mechanical constraints of the UAV CP-SAR system. This research will contribute in the field of radar for remote sensing technology. The potential application is for landcover, disaster monitoring, snow cover, and oceanography mapping.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.225-232
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• 2014

In this study, a cooperative UAV and UGV platform is proposed to obtain a wide range of visual information. The UAV recognizes a pattern marker on UGV and tracks the UGV without user control. It can provide wide range of visual information for a user in the UGV. The UGV by a user is controled equipped with an aluminum board. And the UAV can take off and land on the UGV. The UAV uses two cameras; one camera is used to recognize a pattern marker and another is used to provide a wide range of visual information to the UGV's user. It is guaranteed that the proposed visual-based approach detects and tracks the target marker on the UGV, and then lands well. The experimental results show that the proposed approach can effectively construct a cooperative UAV/UGV platform for obtaining a wide range of vision information.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.279-284
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• 2014

This paper proposes a optimum design method for the Fuzzy PID controller of magnetic levitation-based Rail-Guided Vehicle(RGV). Since an attraction type levitation system is intrinsically unstable, it is difficult to completely satisfy the desired performance through the methods designed by conventional controllers. In the paper, the Fuzzy PID controller with fixed parameters are applied and then the optimum parameters of fuzzy PID controller are selected by genetic algorithm. For the fitness function of genetic algorithm, the performance index of PID controller is used. To verify the performance of the proposed method, we used Matlab/simulink model of Maglev and compared the proposed method with the performance of PID controller. The simulation results show that the proposed method is more effective than conventional PID controller.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.4
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• pp.436-441
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• 2011

A TPMS is a wireless communication system designed to monitor its condition inside the pneumatic tires on various types of vehicles. These systems report the tire pressure information to the driver of the vehicle. While wireless communications is used to transmit the measurement data from TPMS sensors to a central processing unit in the vehicle, it suffers from the various interferences such as sensors of each tire or outside electrical equipments. Based on the conventional beamformer, a switching beamforming technique is proposed to minimize the interference and efficiently receive valid data. Moreover, in order to minimize the interference and reduce power consumption for communication, a system with unique Gold Code is presented for each tire. The performance of interference suppression is illustrated by computer simulations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.12
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• pp.2272-2293
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• 2011

Communication technology of future networks is predicted to provide a large variety of services including WiFi service in vehicular network. In this paper, we assume that vehicles are embedded with WiMAX antenna and in-vehicle terminals receive WiMAX traffic through WiFi interface. This assumption will impose severe performance degradation due to interference among mobile BSSs when WiFi access points (APs) are densely located. Existing interference avoidance techniques cannot properly resolve the above problems and do not cope with dynamically moving vehicular scenario since they focus only on the fixed network topology. In this paper, we propose a mobility-aware interference avoidance scheme for WiFi services. The proposed scheme computes the interference duration by exploiting mobility vector and location information of neighboring APs. If the interference duration is not negligible, our scheme searches for another channel in order to avoid interference. However, if the interference duration is negligible, our scheme continues to use the channel to reduce switching overhead. To measure the effectiveness of the proposed scheme against other existing techniques, we evaluated performance by using OPNET simulator. Through the simulation, we obtained about 60% reduction in the maximum interference frequency and about 67% improvement in throughput. Furthermore, our scheme provides fair channel usage.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2373-2375
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• 2002

전자 제어식 미끄럼 방지 제동 장치(ABS, Anti-lock Brake System)를 장착한 차량의 실차 제동 시험은 시험용 차량을 비롯하여, 많은 분석장비를 필요로 한다. 이러한 고가의 장비는 구하기가 어려울 뿐만 아니라 사용방법을 학습하는 데에도 상당한 기간을 필요로 하므로, 개발중인 ABS에 대하여 적용해 보기에는 그 사용에 제약을 받는다. 본 논문에서는 개발중인 미끄럼방지 제동 알고리즘과 전자제어장치(ECU, Electronic Control Unit)를 대형 버스에 장착하여, 저 점착 노면에서 주행 시험을 시행하였고, 그 주행 기록의 분석을 위하여 DAS(Data Acquisition System)를 구현하였다. 개발 ABS 알고리즘 및 ECU의 기능과 성능 검증이 목적인 DAS는 부가적인 센서 및 고가의 장비를 사용하지 않고 제어보드와 휴대용 노트북 컴퓨터를 이용하였다. 고정밀도의 자료를 획득할 수는 없었지만, 개발 DAS를 이용한 차량 실차 제동 시험은 경제적이면서도 효과적인 ECU 및 알고리즘의 성능 분석을 이룰 수 있었다. 특히 개발 DAS는 제어 및 Data Acquisition을 동일한 보드를 사용하여 구현함으로써, ABS 장착 실차 주행 시험 결과를 제어알고리즘에 즉각적으로 반영시킨 수 있었다. 이러한 One Board System 및 On-Vehicle Programming을 이용한 방법은 개발 알고리즘의 빠른 Debugging 및 파라미터 조정(Tuning)을 가능하게 하였으므로, 실차 제동 시험을 위한 한정된 기간 내에 개발 ABS ECU 및 제어 알고리즘의 성능을 효과적으로 검증할 수 있었다.

• Journal of the Korean Society for Railway
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• v.16 no.6
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• pp.447-453
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• 2013

Since PSDs(Platform Screen Doors) are set up at many subway stations, their design related to safety has become gradually important. In particular, the interference check with a running railway vehicle is the most important of performance indices because the collision between PSDs and vehicles can be dangerous for passengers in the car and on platforms. When the train comes into a station with a curvature, the passenger car has a large translational and rotational motion and the displacement is enough for coming in contact with PSD. The performance is affected by many design parameters such as rail design parameters and vehicle velocity. This study proposes dynamic analysis models for railway vehicles and rails. Some parameters were also considered in the models to determine their influence on the performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.140-147
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• 2011

In this paper, we propose a novel feeding method that uses a windshield ground in a vehicle. The feeding method enables for various antennas to integrate easily in a vehicle windshield. To connect a coaxial feeding cable directly to the windshield ground, we inserted a coaxial-to-ground adapter between the cable and the ground, and reflection coefficients using the proposed feeding method were compared to that using a conventional feeding method. The size and position of the windshield ground were optimized in order to achieve a high radiation gain in the azimuth direction. Then the triangular WiBro patch antenna, incorporating the proposed feeding method, was designed and installed on a rear windshield of a commercial sedan. The antenna using the proposed feeding method shows a similar reflection coefficient, and it shows 2 dB increased average azimuth radiation gain compared to that using a conventional sash ground method. These results demonstrate that the proposed feeding method can be applicable for integrating multiple antennas in a rear windshield.