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Look-up Table Tuning Method for Fuzzy Control
Choi, Han-Soo,Jeong, Heon CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.2
Fuzzy control has many noted features. Control know-how can be expressed easily by rules, a set of partial knowledge can provide for an adequate total control law, and a non-linear controller can be achieved through a set of rules and membership functions. In constructing fuzzy control systems, there are many parameters such as rule base, membership funtions, inference method, defuzzification, and I/O scaling factors. This paper deals with self-tuning of fuzzy control systems. The fuzzy controller has parameters that are input and output scaling factors to effect control output. And we propose the look-up table based self tuning fuzzy controller(LSOFC). We use the plus-minus tuning method(PMTM), tuning the initial look-up table to the properly optimized table by adding and subtracting the values. To shorten the tuning time, we affix the block of the lok-up table inspection. Simulation results demonstrate that the performance of LSOFC is far better than that of a non-tuning fuzzy controller.
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Jeongheon Song,Yongchul Kim 대한인간공학회 2015 大韓人間工學會誌 Vol.34 No.2
Objective: The purpose of this study was to develop and evaluate smart secondary controls using iPad for the drivers with physical disabilities in the driving simulator. Background: The physically disabled drivers face problems in the operation of secondary control devices that accept a control input from a driver for the purpose of operating the subsystems of a motor vehicle. Many of conventional secondary controls consist of small knobs or switches that physically disabled drivers have difficulties in grasping, pulling or twisting. Therefore, their use while driving might increase distraction and workload because of longer operation time. Method: We examined the operation time of conventional and smart secondary controls, such as hazard warning, turn signal, window, windshield wiper, headlights, automatic transmission and horn. The hardware of smart secondary control system was composed of iPad, wireless router, digital input/output module and relay switch. We used the STISim Drive3 software for driving test, customized Labview and Xcode programs for interface control of smart secondary system. Nine subjects were involved in the study for measuring operation time of secondary controls. Results: When the driver was in the stationary condition, the average operation time of smart secondary devices decreased 32.5% in the normal subjects (p <0.01), 47.4% in the subjects with left hemiplegic disabilities (p <0.01) and 38.8% in the subjects with right hemiplegic disabilities (p <0.01) compared with conventional secondary devices. When the driver was driving for the test in the simulator, the average operation time of smart secondary devices decreased 36.1% in the normal subjects (p <0.01), 41.7% in the subjects with left hemiplegic disabilities (p <0.01) and 34.1% in the subjects with right hemiplegic disabilities (p <0.01) compared with conventional secondary devices. Conclusion: The smart secondary devices using iPad for people with hemiplegic disabilities showed significant reduction of operation time compared with conventional secondary controls. Application: This study can be used to design secondary controls for adaptive vehicles and to improve the quality of life of the people with disabilities.
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인공위성 영상레이더를 이용한 멕시코시티 시계열 지반침하 관측
주정헌 ( Jeongheon Ju ),홍상훈 ( Sang-hoon Hong ) 대한원격탐사학회 2021 大韓遠隔探査學會誌 Vol.37 No.6
지반침하는 인위적인 인간 활동 또는 자연적 현상에 의해 지표면이 가라앉는 현상이다. 멕시코시티는 전세계에서 가장 심각한 지반침하가 발생하는 지역 중 하나로 평가받고 있다. 멕시코시티 지반침하의 원인은 과도한 지하수 채취로서 해당 지역 전체의 물 사용량의 약 70%를 지하수가 차지하고 있다. 범 지구 위성 항법 시스템(Global Navigation Satellite System, GNSS) 또는 수준측량과 같은 전통적인 현장 관측 방법은 지반침하를 정확하게 측정하기 위해 선호되어 왔다. 하지만 GNSS 관측은 매우 높은 시간해상도를 가진 정확한 지표 변위량을 측정할 수 있음에도 불구하고, 넓은 지역에 대한 부분적인 관측 정보를 제공하고 많은 시간과 비용이 요구되는 한계점이 존재한다. 그러나, 인공위성 영상레이더(Synthetic Aperture Radar, SAR)는 주야 조건과 기상상태에 관계없이 높은 공간 해상도의 지표변화 정보를 mm에서 cm 크기의 정밀도로 비교적 낮은 비용으로 관측할 수 있다는 점에서 효과적인 방법으로 제시되고 있다. 본 연구에서는 2007년 2월 11일에서 2011년 2월 22일까지 획득된 ALOS PALSAR L-band 영상레이더를 이용하여 멕시코시티의 지반 침하 시계열을 추정하였다. 본 연구에서는 대표적인 시계열 분석 방법인 고정 산란체 위상간섭기법(persistent scatterer interferometry, PSI)과 small baseline subset (SBAS)을 적용하여 지표 변위의 시계열 결과를 획득하였으며 대기 효과 및 지형 오차를 제거하였다. PSI 및 SBAS 기법을 이용한 분석 결과 최대 지반침하 속도는 각각 -29.5 cm/year, -27.0 cm/year로 나타났다. 또한 연구지역을 지질 공학적 특성에 따라 세 가지 구역으로 분류하여 각 분류에서의 지반 침하 속도를 비교한 결과, 단단한 기반암으로 구성된 지역에 비해 압축률이 큰 호수성 퇴적물로 구성된 지역에서 침하가 크게 발생하였다. Anthropogenic activities and natural processes have been causes of land subsidence which is sudden sinking or gradual settlement of the earth’s solid surface. Mexico City, the capital of Mexico, is one of the most severe land subsidence areas which are resulted from excessive groundwater extraction. Because groundwater is the primary water resource occupies almost 70% of total water usage in the city. Traditional terrestrial observations like the Global Navigation Satellite System (GNSS) or leveling survey have been preferred to measure land subsidence accurately. Although the GNSS observations have highly accurate information of the surfaces’ displacement with a very high temporal resolution, it has often been limited due to its sparse spatial resolution and highly time-consuming and high cost. However, space-based synthetic aperture radar (SAR) interferometry has been widely used as a powerful tool to monitor surfaces’ displacement with high spatial resolution and high accuracy from mm to cm-scale, regardless of day-or-night and weather conditions. In this paper, advanced interferometric approaches have been applied to get a time-series of land subsidence of Mexico City using four-year-long twenty ALOS PALSAR L-band observations acquired from Feb-11, 2007 to Feb-22, 2011. We utilized persistent scatterer interferometry (PSI) and small baseline subset (SBAS) techniques to suppress atmospheric artifacts and topography errors. The results show that the maximum subsidence rates of the PSI and SBAS method were -29.5 cm/year and -27.0 cm/year, respectively. In addition, we discuss the different subsidence rates where the study area is discriminated into three districts according to distinctive geotechnical characteristics. The significant subsidence rate occurred in the lacustrine sediments with higher compressibility than harder bedrock.
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기계학습을 이용한 주파수 분석을 통한 퍼팅 판별 알고리즘
김정헌(Jeongheon Kim),권혁준(HyeokJun Kwon),이두용(DooYong Lee),박수경(Sukyung Park) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11
Auto-scoring related wearable devices for golf have emerged to meet consumer demands. Wrist-worn devices capable of automatic scoring using inertial sensors are providing user convenience. Impact of putting is, however, relatively small , and it is difficult to extract the putting signal due to influence of the hand grip. In this study, we designed a puttingdiscrimination algorithm for auto-scoring using inertial sensors. The putting-determination consists of selecting a putting phase from arbitrary motion, and extracting a putting signal in the phase. The putting phase was determined by using Convolution Neural Network (CNN). It was determined based on manual labeling by inputting the acceleration and angular velocity data. Putting-signal extraction exploits the phenomenon that vibration caused by natural frequency occurs even for a small impact. And the putting signal is extracted by designing a bandpass filter which passes only the natural frequency in the putting phase. The natural frequency of the putting is analyzed by assuming the putter as a beam, The parameters are estimated to identify the grip boundary conditions. The impact is derived through the frequency analysis, and experimentally verified. The method presented can be employed to increase accuracy of the wrist-type automatic scoring devices for other sports.
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