• 한국항공우주학회지
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• 제50권8호
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• pp.523-530
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• 2022

다양한 임무에서 활용 가능한 무인기 다개체 시스템은 단일 무인기보다 복잡하므로 효율적인 대형 제어방식이 요구된다. 특히 광역 탐색임무에 있어 통신량 및 연산량 부담이 적으며, 무인기간 자율적인 대형 형성이 가능한 분산 제어형의 유동적인 대형 형성이 필요하다. 본 연구는 스캔 면적의 확장 및 탐색 성능향상을 위해 Swarm 대형과 뱅크 정렬 대형, 대형 전체 운동을 고려한 대형 형성 알고리즘을 제안한다. 본 알고리즘은 상대거리에 대해서 2차 진동 특성을 가지며 parameter tuning을 통해 알고리즘을 설계할 수 있다. 또한 통상적인 무인기 시스템에 적합하도록 제어명령을 변환하였고, 시뮬레이션을 통해 알고리즘의 대형 형성 및 운동에 대한 성능을 입증하였다.

• Journal of Computing Science and Engineering
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• 제11권3호
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• pp.79-91
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• 2017

In this paper, the abdominal-deformation measurement scheme is conducted on a shape-flexible mannequin using the DIC technique in a stereo-vision system. Firstly, during the integer-pixel displacement search, a novel fractal dimension based on an adaptive-ellipse subset area is developed to track an integer pixel between the reference and deformed images. Secondly, at the subpixel registration, a new mutual-learning adaptive particle swarm optimization (MLADPSO) algorithm is employed to locate the subpixel precisely. Dynamic adjustments of the particle flight velocities that are according to the deformation extent of each interest point are utilized for enhancing the accuracy of the subpixel registration. A test is performed on the abdominal-deformation measurement of the shape-flexible mannequin. The experiment results indicate that under the guarantee of its measurement accuracy without the cause of any loss, the time-consumption of the proposed scheme is significantly more efficient than that of the conventional method, particularly in the case of a large number of interest points.

• 전자공학회논문지B
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• 제31B권12호
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• pp.27-34
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• 1994

Block matching motion estimation is the most widely used method for motion compensated coding of image sequences. Based on a two dimensional systolic array, VLSI architecture and implementation of the full search block matching algorithm are described in this paper. The proposed architecture improves conventional array architecture by designing efficient processing elements that can control the data prodeuced by efficient search window division method. The advantages are that 1) it allows serial input to reduce pin counts for efficient composition of local memories but performs parallel processing. 2) It is flexible and can adjust to dimensional changes of search windows with simple control logic. 3) It has no idel time during the operation. 4) It can operate in real/time for low and main level in MPEG-2 standard. 5) It has modular and regular structure and thus is sutiable for VLSI implementation.

• 공학논문집
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• 제6권2호
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• pp.11-22
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• 2004

분산제약조건만족문제(Distributed CSP)는 변수와 제약 조건들이 다수의 에이전트에 분산되어 있는 제약조건만족문제를 말한다. 이 개념은 인공지능 분야의 다양한 문제들에게 폭 넓게 적용 할 수 있으며 또한 이와 유사하게, 에이전트 행동들의 일치된 조합을 찾기 위한 멀티에이전트 시스템의 다양한 응용 문제들(분산 자원할당문제, 분산 스케줄링문제, 분산 번역업무 등)이 모두 분산 제약조건만족문제에 속한다고 할 수 있다. 분산제약조건만족문제는다수의 자율적으로 동작하는 에이전트들의 상호작용과 그들 간의 협조에 의해 모든 에이전트들이 갖고 있는 변수들의 값과 그들 간에 존재하는 제약 조건들이 일치(consistency)하는 값을 효율적으로 찾기 위한 양질의 알고리즘 개발에 관한 연구 분야로서 최근에 와서는 멀티에이전트 시스템을 이용하여 분산 제약조건만족문제를 해결하기 위한 효율적인 알고리즘 개발에 관한 연구가 활발하게 진행되고 있다. 이 논문에서는 비동기/병행적인 탐색 과정에서 모든 에이전트들이 그들의 시험적인 값들을 조건에 일치하는 값으로 변경하기 위해 각 에이전트의 우선순위를 동적으로 변경할 수 있게 함으로써 불 일치된 변수의 값을 탐색이 진행되는 동안에도 수정이 가능하도록 하여, 기존 비 동기 되돌림알고리즘의 개선 대상인 되돌림(backtracking)의 효율성을 크게 향상시킬 수 있는 멀티에이전트의 동적 우선순위탐색 알고리즘을 제안하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권2호
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• pp.195-201
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• 2014

Flexible risers have been used extensively in recent years for floating and early production systems. Such risers offer the advantage of having inherent heave compliance in their catenary thereby greatly reducing the complexity of the riser-to-rig and riser-to subsea interfaces. Another advantage with flexible risers is their greater reliability. Concerns about fatigue life, gas permeation and pigging of lines have been overcome by extensive experience with these risers in production applications. In this paper, flexible riser analysis results were compared through coupled and uncoupled dynamic analyses methods. A time domain coupled analysis capability has been developed to model the dynamic responses of an integrated floating system incorporating the interactions between vessel, moorings and risers in a marine environment. For this study, SPM (Single Point Mooring) system for an FSU in shallow water was considered. This optimization model was integrated with a time-domain global motion analysis to assess both stability and design constraints of the flexible riser system.

• 한국연안방재학회지
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• 제1권4호
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• pp.149-155
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• 2014

Flexible risers have been used extensively in recent years for floating and early production systems. Such risers offer the advantage of having inherent heave compliance in their catenary thereby greatly reducing the complexity of the riser-to-rig and riser-to subsea interfaces. Another advantage with flexible risers is their greater reliability. Concerns about fatigue life, gas permeation and pigging of lines have been overcome by extensive experience with these risers in production applications. In this paper, flexible riser analysis results were compared through coupled and uncoupled dynamic analyses methods. A time domain coupled analysis capability has been developed to model the dynamic responses of an integrated floating system incorporating the interactions between vessel, moorings and risers in a marine environment. For this study, SPM (Single Point Mooring) system for an FSU in shallow water was considered. This optimization model was integrated with a time-domain global motion analysis to assess both stability and design constraints of the flexible riser system.

• 대한토목학회논문집
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• 제29권4D호
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• pp.555-561
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• 2009

굴착된 터널 형상 재현에서 단면의 종단 데이터는 터널의 유지를 위해서는 아주 중요하다. 터널이 완성되기전에 설계된 모델을 고려한 완성된 터널의 변형이 고려되어져야 한다. 그리고 변형은 터널 단면 전체를 따라 연속적으로 나타날 수 있다. 본 연구에서는 먼저 수학적 분석으로 접근하였고, 그것을 관측된 터널단면 데이터에 실험 하였다. 그 다음 선추적 방법, 유전자 알고리즘, 패턴 추적 방법 등으로 3D 터널 형상 재현을 비교하였다. 수학적 방법론은 철도 터널과 같은 간단한 원통형은 쉽게 해결이 되었으나, 도로터널과 같은 더욱 복잡한 모델(복심 곡선형과 비원통형)은 구속된 상태하에서 소프트 컴퓨팅 툴을 가지고 해결할 수 있었다. 유전자 알고리즘과 직접탐색법은 많은 계산 시간이 걸렸으나 복잡한 상태하에서 더욱 유연함을 보였으며, 선추적 방법은 초기값들이 제한된 범위 하에서 가장 빠르게 계산되어졌다.

• Steel and Composite Structures
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• 제7권3호
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• pp.253-262
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• 2007

A methodology to design symmetrically laminated fibre-reinforced structures under transverse loads for minimum weight, with manufacturing uncertainty in the ply angle, is described. The ply angle and the ply thickness are the design variables, and the Tsai-Wu failure criteria is the design constraint implemented. It is assumed that the probability of any tolerance value occurring within the tolerance band, compared with any other, is equal, and thus the approach is a worst-case scenario approach. The finite element method, based on Mindlin plate and shell theory, is implemented, and thus effects like bending-twisting coupling are accounted for. The Golden Section method is used as the search algorithm, but the methodology is flexible enough to allow any appropriate finite element formulation, search algorithm and failure criterion to be substituted. In order to demonstrate the procedure, laminated plates with varying aspect ratios and boundary conditions are optimally designed and compared.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.520-525
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• 2003

The determination of unknown parameters in rotating machinery is a difficult task and optimization techniques represent an alternative technique for parameter identification. The Simulated Annealing(SA) and Genetic Algorithm(GA) are powerful global optimization algorithm. This paper proposes new hybrid algorithm which combined GA with SA and local search algorithm for the purpose of parameter identification. Numerical examples are also presented to verify the efficiency of proposed algorithm. And, this paper presents the general methodology based on hybrid algorithm to identify unknown bearing parameters of flexible rotors using measured unbalance responses. Numerical examples are used to ilustrate the methodology used, which is then validated experimentally.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.805-809
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• 2001

This paper is presented to determine the optimal parameters of squeeze film damper using an enhanced genetic algorithm (EGA). The damper design parameters are the radius, length and radial clearance of the damper. The objective function is minimization of a transmitted load between bearing and foundation at the operating and critical speeds of a flexible rotor. The present algorithm was the synthesis of a genetic algorithm with simplex method for a local concentrate search. This hybrid algorithm is not only faster than the standard genetic algorithm, but also gives a more accurate solution and can find both the global and local optimum solution. The numerical example is presented that illustrated the effectiveness of enhanced genetic algorithm for the optimal design of the squeeze film damper for reducing transmitted load.