• Journal of Biosystems Engineering
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• 제18권4호
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• pp.344-350
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• 1993

The purpose of this study is to develop design equations to calculate optimum specifications and dimensions such as weight, engine horsepower, etc. of the tractor necessary to perform stable rotary tillage. The main results of this study are as follows. 1. A wheel-lug ought to receive a special resistance in downward direction which resists the lug's upward motion on wet sticky soil surface. The authors introduce a new academic name of the "lift resistance(上昇抵抗力, 상승저항력)" for such a force which resists retraction of a wheel lug from the soil in the upward trochoidal motion. This force is composed of the frictional force acting on the trailing and the leading lug side, and the "perpendicular adhesion(鉛直付着力, 연직부착력)" acting on the lug face and the undertread face on adhesive soil. 2. The "lift resistance ratio(上昇抵抗力係數, 상승저항력계수)" and the "perpendicular adhesion ratio(鉛直付着力係數, 연직부착력계수)" were defined, which are something similar to the definition of the motion resistance ratio, the traction coefficient, etc. 3. The design equation of the optimum weight of a rotary tiller mounted on the tractor derived by calaulating the forces acting on the rotary blades. 4. The design equations to calculate optimum specifications and dimensions such as weight, engine horsepower, etc. of the tractor necessary to perform stable rotary tillage were derived. It becomes clear that the optimum weight of a rotary tiller and a tractor can be estimated in planning design by means of putting about 21 design factors of the target into the equation. These equations are useful for planning design to estimate the optimum dimensions and specifications of a rotary tiller as well as a tractor by the use of known and/or unknown design parameters.

• 전자공학회논문지SC
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• 제41권1호
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• pp.17-24
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• 2004

본 논문은 2차 시스템에서 시간영역의 설계 사양을 만족하는 최적 강인 LQ-PID 제어기 설계방법을 제안한다. LQ-PID제어기 동조파라미터들은 시간영역의 설계사양인 오버슈트와 정착시간의 설계파라미터들과 LQR의 가중치요소 Q와 R의 관계에 의해서 설계될 수 있었다. 그래서 안정도-강인성뿐만 아니라 시간영역에서의 성능-강인성을 이룰 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제24권2호
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• pp.50-56
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• 2000

This paper presents the design of an optimal state feedback controller for container cranes under some design specifications. To do this, the nonlinear equation of a container crane system is linearized and then augmented to eliminate the steady-state error, and some constraints are derived from the design specifications. Designing the controller involves a constrained optimization problem which classical gradient-based methods have difficulties in handling. Therefore, a real-coding genetic algorithm incorporating the penalty strategy is used. The responses of the proposed control system are compared with those of the unconstrained optimal control system to illustrate the efficiency.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권1호
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• pp.41-55
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• 2015

This study is proposed a new hybrid mount having a moving-magnet type electromagnetic actuator to reduce the vibration transmitted from naval shipboard equipment to the structure of the ship's hull. Optimal design specifications are determined through experimental analysis. The detailed design of the hybrid mount is determined through several design steps with electromagnetic numerical analysis using Maxwell Software(S/W). The hybrid mount that combines a rubber mount and an electromagnetic actuator has a fail-safe function for shock resistance. The mount is fabricated and tested using a universal testing machine to evaluate the design specifications. Finally, numerical simulation of the hybrid mount is performed to confirm control performance and applicability.

• 대한임베디드공학회논문지
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• 제17권3호
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• pp.157-165
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• 2022

As the number of the installed escalators in Korea continues to increase, the accident rate is also increasing. Therefore, it would be necessary to proactively secure safety. PESSRAE is a controller that implements safety functions as electric/electronic/programmable electronic devices to respond to risks that may occur in escalators. Safety Integrity Level (SIL) is assigned to the safety functions of PESSRAE and it must be verified that the quantitative target value according to the SIL level is satisfied. In this paper, the initial PESSRAE is analyzed using the FMEDA (Failure Mode, Effects and Diagnostic Analysis), which is a quantitative safety analysis method, and design improvement specifications are derived from the analysis in order to satisfy the quantitative target values. Based on the derived design specifications, the improved PESSRAE controller was manufactured. And the appropriateness of the design was verified experimentally in a testbed environment simulating the real environment.

• 한국생산제조학회지
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• 제21권5호
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• pp.797-804
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• 2012

Magnesium has a long tradition of use as a lightweight material in the field of automotive industry. This paper presents the design optimization process of Mg armrest frame to minimize its weight by replacing the steel frame. formerly, the analysis of steel armrest frame was peformed to determine the design specifications for Mg armrest frame. The initial design of Mg armrest frame was carried out by topological optimization technique. After six types of design variables and four types of response variables were defined, DOE(Design of Experiment) and RSM (Response Surface Method) were applied in order to measure sensitivity of design variables and realize optimization through regression model. After design optimization, the weight of the optimized Mg armrest frame was reduced by about 3% compared to the initial design of the Mg frame and was decreased by 41.7% in comparison with that of the steel frame. Some prototypical armrest frames were also made by die casting process and tested. The results were satisfying for its design specifications.

• 한국지진공학회논문집
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• 제15권2호
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• pp.35-42
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• 2011

현재까지 축적된 많은 연구결과와 설계기준을 바탕으로 일반적인 중실단면을 갖는 철근콘크리트 교각의 경우 큰 어려움 없이 내진설계가 수행되고 있지만, 중공원형 철근 콘크리트 교각의 경우 실험 및 해석상의 어려움으로 인하여 국내 외적으로 심부구속철근 상세에 대한 명확한 설계기준과 함께 이에 대한 합리적인 구속 모델 및 내진 성능평가 방안 등은 아직까지 미비한 실정이다. 본 연구에서는 주요 설계변수에 따른 중공원형 철근콘크리트 교각의 내진거동 특성을 파악하고, 이를 신뢰성 있는 비선형 유한요소해석 프로그램(RCAHEST)을 통한 결과와의 비교 분석을 바탕으로 보다 경제적이고 합리적인 설계방안 마련을 위한 기초자료를 제시하고자 한다.

• 전력전자학회논문지
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• 제27권4호
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• pp.325-331
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• 2022

This study proposes a design method that minimizes a conduction loss of LCC resonant converter under rated condition. Through a simplified analysis of the waveform of the resonant current, the power transfer section and RMS value of the resonant current was analyzed mathematically and graphically. Based on this analysis, the design method that minimizes the RMS value of the resonant current is proposed. To demonstrate this method, this study designed a 7.5 kW (100 V, 75 A) capacitor charger based on LCC resonant converter and the design parameters were chosen according to the process of the design method. Then, the capacitor charger was implemented. An experiment was conducted to measure efficiency while satisfying design specifications under rated conditions. This design method was verified to be effective by achieving 97.7% maximum efficiency and design specifications under rated conditions.

• Structural Engineering and Mechanics
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• 제58권3호
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• pp.597-612
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• 2016

This paper presents an optimization process using Harmony Search Algorithm for minimum weight of steel space frames under earthquake effects according to Turkish Earthquake Code (2007) specifications. The optimum designs are carried out by selecting suitable sections from a specified list including W profiles taken from American Institute of Steel Construction (AISC). The stress constraints obeying AISC-Load and Resistance Factor Design (LRFD) specifications, lateral displacement constraints and geometric constraints are considered in the optimum designs. A computer program is coded in MATLAB for the purpose to incorporate with SAP2000 OAPI (Open Application Programming Interface) to perform structural analysis of the frames under earthquake loads. Three different steel space frames are carried out for four different seismic earthquake zones defined in Turkish Earthquake Code (2007). Results obtained from the examples show the applicability and robustness of the method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1990년도 봄 학술발표회 논문집
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• pp.84-89
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• 1990

The objective of this study is to optimize the section of RC box culvert and develop a CAD system for drawing. This paper consists of three parts. In the first part, the external load conditions are systematized by using the literatures and specifications. In the second one, the RC box culvert is optimized using the SUMT algorithm. Sizing variables, and steel ratio are taken as design variables, and a cost function as the objective function. The stress and side constraints are derived from the Korea Concrete Specifications for the ultimate strength design. Finally, a data base and CAD system is developed for the drawing of the optimized section of RC box culverts.