• 농업과학연구
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• 제48권3호
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• pp.597-606
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• 2021

Due to the characteristics of the farmland in Korea, forward and reverse shift is the most used. The fatigue of farmers is caused by forward and reverse shifting with a manual transmission. Therefore, it is necessary to improve the convenience of forward and backward shifting. This study was a basic study on the development of a current control system for forward and reverse shifting of agricultural tractors using proportional control valves and a controller. A test bench was fabricated to evaluate the current control accuracy of the control system, and the stability of the controller was evaluated through CPU (central processing unit) load measurements. A controller was selected to evaluate the stability of the proportional valve controller. The stability evaluation was performed by comparing and analyzing the command current of the controller and the actual current measured. The command current was measured using a CAN (controller area network) communication device and DAQ (data acquisition). The actual current was measured with a current probe and an oscilloscope. The control system and stability evaluation was performed by measuring the CPU load on the controller during control operations. The average load factor was 12.27%, and when 5 tasks were applied, it was shown to be 70.65%. This figure was lower than the CPU limit of 74.34%, when 5 tasks were applied and was judged to be a stable system.

• Geomechanics and Engineering
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• 제23권2호
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• pp.127-137
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• 2020

To study the reverse fault formation process and the stress evolution feature, a simulation test system of reverse fault formation is developed based on the analysis of reverse fault formation mechanism. The system mainly consists of simulation laboratory module, operation console and horizontal loading control system, and data monitoring system. It can represent the fault formation process, induce fault crack initiation and simulate faults of different throws. Simulation tests on reverse fault formation process are conducted by using the simulation test system: horizontal loading is added to one side of the model. the bottom rock layer cracks under the effect of the induction device. The crack dip angle is about 29°. A reverse fault is formed with the expansion of the crack dip angle towards the upper right along the fracture surface and the slippage of the hanging wall over the foot wall. Its formation process unfolds five stages: compressive deformation of rock, local crack initiation, reverse fault penetration, slippage of the hanging wall over the foot wall and compaction of fault plane. There is residual structural stress inside rock after fault formation. The study methods and results have guiding and referential significance for further study on reverse fault formation mechanism and rock stress evolution.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.340-344
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• 2004

This paper is the performance evaluation of reverse engineering system using simple mechanism. The existing equipment didn't use in the field popularly as it is too expensive. So we constructed the reverse engineering system of simple mechanism using the laser sensor, LM guide, micro step driver and control program. And we caught the Characteristics to measure some product. Finally we confirmed the precision to compare measured data and CAD date.

• 전자공학회논문지A
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• 제33A권5호
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• pp.10-23
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• 1996

In this paper, the reverse link performance evaluation with synchronous CDMA is analyzed in the PCS system, which is the schem based on proposed method of KMT-PCS to increase the capacitance of cellular CDMA system. We make the baseband system model of CDMA reverse link, and then analyze system performance and subsystem techniques considering effect of channel and power control that are improtant factor influencing system performance in the PCS system. Based on this result, the paper presents primary technique analyses required at synchronous reverse link proposed by the KMT, which compose of initial synchronization range in initial synchronization step and control signal period in the synchronization maintenance step.

• 한국통신학회논문지
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• 제32권7A호
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• pp.686-693
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• 2007

와이브로 상향링크의 경우 개방형 전력제어에서는 피드백 없이 전력 할당을 하기 때문에 피드백에 사용될 무선자원을 절약 할 수는 있지만 단말에 정확한 전력 할당을 하기 어렵다. 이에 본 논문은 잡음간섭 값을 현재 무선 환경에 적응하는 방법을 제시하여 순시적으로 변화하는 무선 환경에 적합하게 하고 전력 할당의 상/하향 계단값 결정 방법을 대칭형과 비대칭형으로 제안하여 비교 실험하였다. 컴퓨터를 이용한 실험을 통해서 시스템 파라미터에 따라 상/하향 계단값을 다르게 적용할 때 높은 섹터 처리율과 낮은 오류율 결과를 얻을 수 있다는 것을 알 수 있다.

• 대한전기학회논문지
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• 제39권4호
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• pp.349-356
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• 1990

In order to control DC motors for electric cars by chopper system, four quadrant operations - forward powering, forward regenerative braking, reverse powering, reverse regenerative braking - are needed. For the four quadrant operations, the separately - excited DC motors are used in this study. The conversion of each quadrant operation has been obtained by 1) adopting the two phase chopper system with combined output for the armature control, and 2) the single phase chopper system for the field control.

• 대한치과보철학회지
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• 제40권3호
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• pp.246-261
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• 2002

The screw loosening is one of the complications that happen frequently in dental implant prostheses. The purpose of this study was to evaluate the changes of reverse/loosening (opening) torque of the screw according to the surface modifications by sandblasting and 24K gold electroplating as well as to determine the possibility of the clinical use of a washer in dental implant. The reverse torque of 4 experimental conditions(control, sandblasted, use of washers, electroplasted) was measured by digital torque gauge (Model MGT50Z, Mark-10 Corp., 458 West John Street Hicksville, NY 11801 USA). Electronic torque controller (Nobel Biocare DEA 020) was used in fastening the gold screws into abutment replicas. Mixed Linear Model Analysis method was used for statistical analysis. To examine the changes of screw thread surface, microphotographs were taken by Olympus PME-3 metallurgic microscope (Olympus Optical Co. Ltd., Tokyo, Japan). Within the limitations of this study, the following results were drawn: 1. The surface modifications of the gold screws and the use of a washer have significantly affected the reverse torque value compared to the control group (P<0.01). 2. Sandblasting and electroplating treatments demonstrated significantly higher reverse torque value than that of control group. 3. The use of a washer may be one of the useful clinical methods that prevent the screw loosening. However, further studies are necessary for the material selection and design of the washer.

• Management Science and Financial Engineering
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• 제8권1호
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• pp.53-75
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• 2002

In this Paper, an attempt is made to establish a learning framework for robust planning and real-time execution control. Necessary definitions and concepts are clearly presented to describe real-time operational control in response to Plan disruptions. A general mathematical framework for disruption recovery is also laid out. Global disruption model is decomposed into suitable number of local disruption models. Execution Pattern is designed to capture local disruptions using decomposed-reverse neural mappings, and to further demonstrate how the decomposed-reverse mappings could be applied for solving disrubtion recovery problems. Two decomposed-reverse neural mappings, N-K-M and M-K-N are employed to produce transportation solutions in react-time. A potential extension is also discussed using the proposed mapping principle and other hybrid heuristics. Experimental results are provided to verify the proposed approach.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.525-528
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• 2002

A Novel Zero Current Switching(ZCS) Pulse Width Modulation(PWM) boost converter for reducing two rectifiers reverse recovery related losses Is proposed. The switches of the proposed converter are operating to work alternatively turn-on and turn-off with soft switching(ZVS, ZCS) condition. The reverse recovery related switching losses and EMI problems of the proposed converter eliminates the reverse recovery current of the freewheeling diode(D, Dl) by adding the resonant inductor Lr, in series with the switch S2. The voltage and current stresses of the components are similar to those in its conventional hard switching counterpats. As mentioned above, the characteristics are verified through experimental results.

• 대한산업공학회지
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• 제40권2호
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• pp.205-214
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• 2014

As a result of the rapid economic growth and birth control policy, China is experiencing low fertility rates and increasing life expectancy, which makes Chinese population aging very quickly and unprepared for their retired life. The reverse mortgage may be an attractive option for the elderly because it is a loan against a house that they do not have to pay back as long as they live there. In this paper, in order to introduce the reverse mortgage scheme in China the factors that could influence the demand of reverse mortgage are reviewed and the Chinese market environment is analyzed. Then the principal component analysis is performed in order to recommend the regions or cities that have higher potential for successful implementation of a reverse mortgage than any other ones in China.