• Journal of KIISE:Computing Practices and Letters
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• 제5권2호
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• pp.223-235
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• 1999

본 논문에서는 HDTV 데이터를 입출력할 수 있는 고속 실시간 데이터 저장 시스템을 제안한다. 이 시스템은 ⅰ) 방대한 크기를 HDTV 데이터를 고속으로 입출력할 수 있어야 한다. ⅱ)데이타를 연속적으로 입출력할 수 있는 것 외에 데이터를 비선형적으로 랜덤하게 억세스 할 수 있어야 한다. ⅲ)실시간으로 데이터를 재생하기 위해 일정하게 주어진 시스템 입출력 속도를 항상 만족할수 있어야 한다. 이러한 조건을 만족시키기 위해서 여러 개의 하드디스크를 병렬로 연결하고 데이터들을 각각의 하드디스크에 나누어 저장하였다. 하드디스크의 입출력 성능은 하드디스크 아암의 탐색 동작에 의해 크게 좌우되므로 탐색 동작을 효과적으로 제어할 수 있는 방법이 설계되었다. 제안된 시스템은 주제어부, 데이터 분배부, 종제어부로 나뉘며 각각의 하드디스크는 독립도니 종제어부에 의해 제어된다. 제안된 시스템이 주어진 요구사항을 만족하는지를 확인하기 위하여, 제안된 시스템을 DEVS 형식론을 이용하여 구현하고 시뮬레이션 하였다. DEVS 형식론은 이산사건 시스템을 계층적이고 모듈화된 형태로 기술한다. 시뮬레이션 과정에서 발생된 사건들을 분석하였다. 그 결과 제안된 시스템이 주어진 요구사항을 잘 만족함을 보았다.

• Proceedings of the KIPE Conference
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.148-150
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• 2020

모듈러 구조의 전력변환 장치는 고전류 및 고전력이 요구되는 어플리케이션에 사용한다. 일반적으로 모듈러 구조의 전력변환 장치는 전체 출력 전력을 각각의 단일 전력변환 장치의 출력 전력에 균등하게 분배되도록 제어하여 부하 부담을 모든 개별 전력변환 장치로 분산한다. 하지만 기존의 출력 전력 균등화 제어는 전력변환 장치 간의 전력변환 효율 차이에 대하여 능동적으로 대응할 수 없기 때문에 모듈러 구조의 전력변환 시스템의 전력변환 효율과 신뢰성을 저감할 수 있다. 본 논문에서는 개별 전력변환 장치 간의 실제적인 효율 차이를 고려하여 출력 전력이 아닌 입력 전력에 대하여 모듈러 구조로 구성된 개별 전력변환 장치의 부하를 조절하는 입력 전력 균등화 제어방법을 제안한다. 제안하는 입력 전력 균등화 제어 방법은 2개의 200 W급 모듈러 벅 컨버터를 통해 검증하였다.

• Journal of the Korean Society for Precision Engineering
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• 제25권2호
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• pp.72-79
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• 2008

In the redundant actuation system which has more actuators than a system's mobility, there are various method to determine actuated torques because those are not determined uniquely. This paper presents a torque distribution method using weighted-pseudoinverse to optimize the maximum torque of various actuated inputs of the redundant system. The various weighting factor of weighted-pseudoinverse is studied to reduce maximum actuated torque. This method is experimentally applied to 3RRR parallel robot, which shows that presented method can efficiently reduce the maximum actuated torque.

• Korean Journal of Food Science and Technology
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• 제20권6호
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• pp.845-849
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• 1988

A laboratory scale storage facility consisting of a cold room, sample jars and a ventilation device was designed and built. Storaging sample jars (1.7 l) for fruit were fabricated with transparent acryl and provided with a constant air flow. For the supplying of air to sample jars, the air distributing system was built with solenoid valves, an air precooling coil and a pressure equalizing tank. To provide the programmable storaging environment of the facility a microprocessor-based controller was designed and installed. The controller was built with the 8 bit microprocessor (Z-80), EPROM, RAM, programmable peripheral interface(8255 PPI), and A/D converter. Softwares for the auto-temperature measurement and control of the storage system were developed and systemized in ROM. The automated storage system was applied to citrus storage, and the temperature of the storage facilities was successfully acquisited to the computer and controlled.

• Transactions of the Korean Society of Automotive Engineers
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• 제21권6호
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• pp.209-217
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• 2013

This paper presents a control strategy of 4 wheel drive (4WD) vehicles. Proposed control strategy has simple structure and can easily apply to various vehicles with low cost and time. It is consist of feedforward control for traction ability, fedback control for minimizing the wheel speed difference and yaw control for lateral stability. In addition, to integrate the traction and stability control, a blending function is applied. To evaluate the feasibility of the proposed control strategy, actual vehicle experiment is conducted after deciding the tuning parameter through the simulation. The simulation is accomplished by CarSim and Matlab/Simulink and the actual vehicle test is conducted using full size Sports Utility Vehicle (SUV) equipped rear wheel based solenoid type 4WD device.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제34권6호
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• pp.659-665
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• 2010

This paper proposes a control algorithm for quadruped robots moving on irregularly sloped uneven surfaces. Since the body balance of a quadruped robot is controlled by the forces acting on its feet during touchdown, the ground reaction force (GRF) is controlled for stable running. The desired GRF for each foot is generated on the basis of the desired galloping pattern; this GRF is then compared with the actual contact force. The difference between the two forces is used to modify the foot trajectory. The desired force is realized by considering a combination of the rate change of the angular and linear momenta at flight. Then, the amplitude of the GRF to be applied at each foot in order to achieve the desired linear and angular momenta is determined by fuzzy logic. Dynamic simulations of galloping motion were performed using RecurDyn; these simulations show that the proposed control method can be used to achieve stable galloping for a quadruped robot on irregularly sloped uneven surfaces.

• The Transactions of the Korean Institute of Power Electronics
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• 제11권6호
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• pp.535-542
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• 2006

A large signal stability analysis of the solar array regulator system is performed to facilitate the design and analysis of a Low-Earth-Orbit satellite power system. The effective load characteristics of every controllable method in the solar array system are classified to analyze the large signal stability. Then, using the state plane analysis technique, the stability of various equilibrium points is analyzed. A nonlinear transformation algorithm, which changes the effective load characteristic of the solar array regulator as constant resistive load, is also proposed for the large signal stability. The proposed resistive current mode control system can control the solar array output for purposes such as peak power tracking control and battery charging control. For the verification of the proposed large signal analysis and resistive current mode control, a solar array regulator system consisting of two 100W parallel module buck converters has been built and tested using a real 200W solar array.

• Journal of the Korean Geographical Society
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• 제46권6호
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• pp.673-692
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• 2011

Advances in computer technology have enabled us to develop and use numerical landscape evolution models (NLEMs) for exploring the dynamics of geomorphic system from a variety of viewpoints which previously could have not been taken. However, as of yet there have been no trials using or developing NLEMs in Korea. The purpose of this research is to develop a 2 dimensional NLEM on a geological time scale and evaluate its usefulness. The newly developed NLEM (ND-NLEM) treats bedrock weathering as one of the major geomorphic processes and attempts to simulate the thickness of soil. As such it is possible to model the weathering-limited as well as the transport-limited environment on hillslopes. Moreover the ND-NLEM includes not only slow and continuous mass transport like soil creep, but also rapid and discrete mass transport like landslides. Bedrock incision is simulated in the ND-NLEM where fluvial transport capacity is large enough to move all channel bed loads, such that ND-NLEM can model the detachment-limited environment. Furthermore the ND-NLEM adopts the D-infinity algorithm when routing flows in the model domain, so it reduces distortion due to the use of the steepest descent slope flow direction algorithm. In the experiments to evaluate the usefulness of the ND-NLEM, characteristics of the channel network observed from the model results were similar to those of the case study area for comparison, and the hypsometry curve log during the experiment showed rational evidence of landscape evolution. Therefore, the ND-NLEM is shown to be useful for simulating landscape evolution on a geological time scale.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제23권5호
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• pp.487-494
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• 2019

A Small-Sat Power System Design and Development should be depend on space environment such as solar wind with Electromagnetic field by hurdle of techniques. It is surmount solution of trend that will unitize and converge with power module in these days. The level of modularize means that applying Universal Middleware for payload power module requirements. The scope of target system is a main power provider module and operational subunit that can be implemented with the final power module distribution loads to consume for continuous process. A Universal Middleware strengthen to build power module from satellite power system should be accuracy and consuming data. A Power Service Module and dynamic system drive interactive management between power distribution and consumer module by Range Control. Consequently, suggesting evaluation, unexpecting payload system power consumer that makes fine variable resources in the development design process and efficiency.

• Transactions of the Korean Society of Automotive Engineers
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• 제23권6호
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• pp.633-641
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• 2015

The ROM (roll over mitigation) system is a next-generation suspension system that can improve vehicle-driving stability and ride comfort. Currently, mass-produced safety systems, such as ESC (electronic stability control) and ECS (electronic control suspension), enable measurements of longitudinal and lateral acceleration as well as yaw rate through inertial sensor clusters, but they lack direct measurements of the roll angle. Therefore, in this paper, a roll angle estimation algorithm from ESC system sensors and tire normal force has been proposed. Furthermore, this study presents a method for roll over mitigation force distribution between the front and rear of a ROM system. Performance and reliability of the roll angle estimation and roll over mitigation force distribution were investigated through simulations. The simulation results showed that the proposed control algorithm and strategy are reliable during vehicle rollovers.