• 한국지능시스템학회논문지
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• 제4권3호
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• pp.32-48
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• 1994

This paper proposes the compensation algorithm of conventional shift pattern using fuzzy reasoning in automatic transmission vehicles. Recently, automatic transimssion vehicles are continually increasing because of theire ease to drive. Also users require the high performance which includes the smooth shift quality and shift scheduling that matches driver;s intentions. So the shift scheduling has been inproved significantly through the application of electronic control. But, in spite of this development, vehicles using conventional shift pattern are sometimes in discord with driver's intention on roads. In this paper, the paper, the proposed compensation algorithm makes a automatic transmission vehicle be able to select an optimal gear shifting time and position using fuzzy reasoning and make a vehicle driver feel confortable even when the vehicle runs on roads which is extremely changed. Therefore, a vehicle driver can expect to reduce the nimber of unnecessary gear shifting and expect the fuel efficiency high. To show usefulness of the proposed method, some simulation are made to compared with conventional gear shifting. Paper prosposes the compensation mehtod of conventional shift pattern using fuzzy reasoning for the purpose that a vehicle can select an optimal gerar shifting time and position in automatic vehicle. Though the conventional shift pattern has no pliability, vehicle driver can feel comfortable and can reduce the number of unnecessary gear shifting using the proposed method on variable road condition. Therefore, it can be expected the fuel efficiency.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제22회 KOSCI SYMPOSIUM 논문집
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• pp.90-98
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• 2001

Characteristics of high temperature rocket nozzle flow is discussed along with the aspects of computational analysis. Three methods of nozzle flow analysis, frozen-equilibrium, shifting-equilibrium and non-equilibrium approaches, were discussed, those were coupled with the methods of computational fluid dynamics code. A chemical equilibrium code developed for the analysis of general hydrocarbon fuel was coupled with three approaches of nozzle flow analysis. The approaches were used for the performance prediction of KSR-III Rocket, and compared with the theoretical results from NASA CEA (Chemical Equilibrium with Applications) code.

• 한국통신학회논문지
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• 제25권3B호
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• pp.464-471
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• 2000

The number of quantization bits of the input signals $X_k$,$Y_k$ need to be optimally determined through the trade-off between the H/W complexity and the BER performance in Turbo codes applications. Also, an effective means to incorporate a channel reliability $L_c$ in the Log-MAP-based Turbo decoding is highly required. because it has a major effect on both the complexity and the performance. In this paper, a novel bit-shifting approach that substitutes for the multiplying is proposed so as to effectively incorporate. $L_c$ in Turbo decoding. The optimal number of quantization bits of $X_k$,$Y_k$ is investigated through Monte-Carlo simulations assuming that bit-shifting approach is adopted. In addition. The effects of an incorrect estimation of noise variance on the performance of Turbo codes is investigated. There is a confined range in which the effects of an incorrect estimation can be ignored.

• 전자공학회논문지
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• 제52권4호
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• pp.71-79
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• 2015

본 논문에서는 상호 정전용량 터치스크린의 single line sensing 방법에서의 단점을 해결하기 위한 성능향상 구조를 제안한다. 제안 구조는 Dual sensing 기법과 voltage shifting 기법을 도입하여 센싱 신호의 노이즈를 효과적으로 제거하고 터치 유무의 센싱 신호 차이를 증가시킨다. Dual sensing 기법은 구동신호의 양방향 엣지를 사용하여 integration 속도를 2배로 증가시켜 감지시간을 감소시킨다. Voltage shifting은 ADC의 입력신호 동작범위를 최대화하여 신호 대 노이즈비 (SNR)를 개선한다. 23" 대형 상용 터치스크린을 이용하여 simulation 및 측정한 결과로 제안된 센싱기법은 43dB의 SNR 성능을 가지며, 기존 방식 대비 2배의 스캔 속도를 제공하여 대형 터치스크린을 위한 적합한 기술임을 보인다. 제안된 센싱기법은 현재 매그나칩 CMOS 0.18um 공정으로 TSP 컨트롤러칩으로 구현되었다.

• Journal of Mechanical Science and Technology
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• 제15권11호
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• pp.1472-1481
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• 2001

In this paper, an advanced shift controller that supervises the shift transients with adaptive compensation is presented. Modern shift control systems for vehicle automatic transmission are designe d to provide smooth transients for passengers' comfort and better component durability. In the conventional methods, lots of testing and calibration works have been done to tune gains of the controller, but it does not assure optimum shift quality at all times owing to system variations often caused by uncertainties in shifting hydraulic systems and external disturbances. In the proposed control scheme, an adaptive compensation controller with intelligent supervisor is implemented to achieve improved shift quality over the system variations. The control input pattern which generates clutch pressure commands in hydraulic actuating systems, is updated through a learning process to adjust for each subsequent shift based on continuous monitoring of shifting performance and environmental changes. The proposed algorithm is implemented and evaluated on the experimental test setup. Results from the experimental studies for several operation modes show both improved performance and adaptability of the proposed shift controller to uncertain changes of the shifting environment in vehicle power transmission systems.

• 한국소음진동공학회논문집
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• 제24권1호
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• pp.54-61
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• 2014

This paper proposes a driver supportive device with haptic cue function which can transmit optimal gear shifting timing to a driver without requiring the driver's visual attention. Its performance is evaluated under vehicle model considering automotive engine, transmission and vehicle body. In order to achieve this goal, a torque feedback device is devised and manufactured by adopting the MR (magnetorheological) fluid and clutch mechanism. The manufactured MR clutch is then integrated with the accelerator pedal to construct the proposed haptic cue device. A virtual vehicle emulating a four-cylinder four-stroke engine, manual transmission system of a passenger vehicle and vehicle body is constructed and communicated with the manufactured haptic cue device. Control performances including torque tracking and fuel efficiency are experimentally evaluated via a simple feed-forward control algorithm.

• Journal of the Optical Society of Korea
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• 제10권3호
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• pp.118-123
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• 2006

We present an optical security method for binary data information by using 4-step phase-shifting digital holography and we analyze tolerance error for the decrypted data. 4-step phase-shifting digital holograms are acquired by moving the PZT mirror with equidistant phase steps of ${\pi}/2$ in the Mach-Zender type interferometer. The digital hologram in this method is a Fourier transform hologram and is quantized with 256 gray level. The decryption performance of the binary data information is analyzed. One of the most important errors is the quantization error in detecting the hologram intensity on CCD. The greater the number of quantization error pixels and the variation of gray level increase, the more the number of error bits increases for decryption. Computer experiments show the results for encryption and decryption with the proposed method and show the graph to analyze the tolerance of the quantization error in the system.

• 한국소음진동공학회논문집
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• 제23권2호
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• pp.160-166
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• 2013

This paper proposes a driver supportive device with haptic cue function which can be applicable for vehicles adopting manual transmission system to transmit gear-shifting information to a driver by kinesthetic forces. This haptic cue function is implemented on accelerator pedal by utilizing magnetorheological(MR) fluid and clutch mechanism. In order to achieve this goal, an MR clutch mechanism is devised to be capable of rotary motion of accelerator pedal. The proposed MR clutch is then optimally designed and manufactured under consideration of spatial limitation of vehicles. After transmission torque is experimentally evaluated according to field intensity. The manufactured MR clutch is integrated with accelerator pedal and electric motor to establish the haptic cue device. Control performances are experimentally evaluated via a simple feed-forward control algorithm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.110-113
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• 2001

We present an interferometer system, which is able to perform both the phase shifting interferometry and white light interferometry. The interferometer system uses a d.c. motor to control the probe position with an accuracy of 10nm, which shows an outstanding performance on white light interferometry. However, the moving mechanism of d.c. motor is not accurate enough for the phase shifting interferometry that requires a moving precision less than 1 nm. We therefore propose a Fourier transform technique to calculate the phase of interferograms, which is strongly resistant to calibration errors and external vibration. Experimental results show that the Fourier transform technique is capable of reducing the measurement error caused by inaccurate movement within 0.1nm.

• 드라이브 ㆍ 컨트롤
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• 제15권3호
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• pp.36-42
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• 2018

Agricultural tractors require frequent shifting to improve operation efficiency, and PST (Powershift Transmission) is considered as a suitable transmission. However, due to the inherent characteristics of the PST, shocks arise during shifting, which imparts a negative effect on the operator. Therefore, in order to improve the transmission performance of the tractor PST, researches on various methods including the hydraulic system circuit, the engine input speed control, and the mechanical system of the transmission are steadily being conducted. In this study, in order to reduce the impact of PST on a shift based on SimulationX software, we analyzed the characteristics of the input signal of PCV (Pressure Control Valve) through sensitivity analysis and verified the simulation model through actual vehicle test. Optimization was performed for minimizing the shift shock for some of the parameters of the input signal at constant temperature and RPM conditions.