• 대한전자공학회논문지TC
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• 제43권8호
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• pp.1-14
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• 2006

실시간 멀티미디어 서비스들을 전송하는 DWDM(Dense-Wavelength Division Multiplexing) 기반의 차세대 인터넷에서는 DWDM 망의 다양한 QoS(Quality of Service) 파라미터들을 복합적으로 고려하는 QoS RWA(Routing and Wavelength Assignment) 방식으로의 접근이 요구되어진다. 본 논문은 flooding 방법을 기반으로 하고, 다중제약조건을 만족하는 새로운 QoS 라우팅 알고리즘인 Bounded Flooding Routing (BFR)을 제안한다. BFR 알고리즘의 주요 목적은 network overhead, blocking probability 그리고 wavelength utilization의 성능 분석 파라메터의 향상에 있다. 더욱이, 이러한 목적을 달성하기 위해 본 논문에서는 새로운 개념인 ripple count 개념을 제안하여, 링크 상태정보 및 계산량을 줄임으로써 라우팅의 성능을 높인다. 또한, 제안된 알고리즘의 광범위한 분석을 위해서, DWDM을 기반으로 하는 망에서 중요한 요소인 제한된 파장 변환기를 적용한다. 제안된 BFR 알고리즘의 성능분석 결과는 본 논문에서 제시하는 방법이 network overhead, blocking Probability 그리고 wavelength utilization 측면의 성능 평가를 통해 제안된 알고리즘들의 효율성을 검증하였다.

• 대한기계학회논문집A
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• 제20권6호
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• pp.1827-1835
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• 1996

This paper addresses the problem of a torch path generation for the 2D laser cutting of a stock plate nested with resular or irregular parts. Under the constaint of the relative positions of parts enforced by nesting, the developed torch path algorithm generate feasible cutting path. In this paper, the basic object is a polygon( a many-slide figure) with holes. A part may be represented as a number of line segments connected end-to-end in counterclockwise order, and formed a closed contour as requied for cutting paths. The objective is to tranverse this cutting contours with a minimum path length. This paper proposes a simulated annealing based dtorch path algorithm, that is an improved version of previously suggested TSP models. Since everypiercing point of parts is not fixed in advance, the algorithm solves as relazed optimization problem for the constraint, thich is one of the main features of the proposed algorithm. For aolving the torch path optimization problem, an efficient generation mechanism of neighborhood structure and as annealing shedule were introduced. In this way, a global solution can be obtained in a reasonable time. Seveeral examples are represented to ilustrate the method.

• 한국정보과학회논문지:소프트웨어및응용
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• 제31권6호
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• pp.817-828
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• 2004

본 논문에서는 몽타주 기법과 음영합성 기법을 이용한, 디자이너(예술가)의 감각을 살린 벡터 기반의 얼굴 생성 시스템을 제안한다. 제안하는 시스템은 사진으로부터 얼굴의 특징정보를 추출하여 사람의 얼굴과 유사한 얼굴을 자동으로 생성해 주는 시스템이며, 윤곽선만을 사용하던 기존의 얼굴 생성 시스템과 달리 컬러 기반이며, 음영을 사진으로부터 추출하여 이를 이목구비 이미지와 합성하여 생성하는 방식이다. 따라서 실사형에 좀 더 근접한 얼굴을 생성할 수 있다는 장점을 갖는다. 또, 벡터를 기반으로 하기 때문에 사이즈에 제한 얼이 자유로운 변형이 가능할 뿐만 아니라 디자이너 또는 그림 작가의 느낌을 결과물에 그대로 유지할 수 있도록 한다는 점에서 타 접근방식과의 차별성을 갖는다. 또, 2D 아바타에 자유로운 표정을 적용하는 데에도 쉽게 적용이 가능하다.

• 대한기계학회논문집A
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• 제27권8호
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• pp.1418-1425
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• 2003

In CAD systems, a surface to be machined is expressed by a series of curves, such as B-spline, Bezier and NURBS curves, which compose the surface and then in CAM systems the curves are divided into a large number of line or arc segments. These divided movement commands, however, cause many problems including their excessive size of NC data that makes almost impossible local adjustment or modification of the surface. To cope with those problems, the necessity of real-time curve or surface interpolators was embossed. This paper presents an efficient real-time tool-path generation method fur interpolation of NURBS surfaces in CNC machining. The proposed tool-path generation method is based on an improved iso-scallop strategy and can provide better precision than the existing methods. The proposed method is designed such that tool-path planning is easily managed in real-time. It proposed a new algorithm for regulation of a scallop height, which can efficiently generate tool-paths and can save machining time compared with the existing method. Through computer simulations, the performance of the proposed method is analyzed and compared with the existing method in terms of federate, total machining time and a degree of constraint on the scallop height.

• International Journal of Precision Engineering and Manufacturing
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• 제5권1호
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• pp.27-35
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• 2004

In the field of machine vision using a single camera mounted on a mobile robot, although the detection and tracking of moving objects from a moving observer, is complex and computationally demanding task. In this paper, we propose a new scheme for a mobile robot to track and capture a moving object using images of a camera. The system consists of the following modules: data acquisition, feature extraction and visual tracking, and trajectory generation. And a single camera is used as visual sensors to capture image sequences of a moving object. The moving object is assumed to be a point-object and projected onto an image plane to form a geometrical constraint equation that provides position data of the object based on the kinematics of the active camera. Uncertainties in the position estimation caused by the point-object assumption are compensated using the Kalman filter. To generate the shortest time trajectory to capture the moving object, the linear and angular velocities are estimated and utilized. The experimental results of tracking and capturing of the target object with the mobile robot are presented.

• 한국정밀공학회지
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• 제27권11호
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• pp.72-77
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• 2010

The fatigue characteristic of a material or a structure is derived from fatigue tests of standard specimens. However, many test results of standard specimens are very different from those of real structures. One reason for this difference is the constraint effects according to the geometrical difference. Therefore, to calculate more accurate fatigue life, the constraint effect must be considered by comparing test results of standard specimens with those of real structures. In this study, a blade of an air-conditioner was evaluated by both the test and the analysis. The results showed that a standard specimen is conservative, compared with a structure specimen. And fatigue life of an air-conditioner's blade was predicted from those.

• 에너지공학
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• 제6권2호
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• pp.129-136
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• 1997

본 연구는 전력계통의 화력발전소로부터 배출되는 NOx및 SO$_2$같은 대기환경오염물질을 고려한 새로운 경제부하배분법을 제시한다. 제안된 방법은 총배출량 제약, 지역별 배출랑 제약 그리고 이들의 동시제약을 만족하면서 화력발전기의 출력을 계획하는 것에 대해 설명되어진다. 또한, 모든 부하배분의 대체안이며 배출량과 총연료비 사이의 상호상충관계를 나타내는 Trade-Off곡선에 의해 배출량과 총연료비 사이의 감도해석이 이 알고리즘에 적용된다. 한편, 이 제안된 방법은 개별적 환경피해(NOx, SO$_2$등)의 상대적 가중치와 총환경비용의 함수로써 경제부하배분이 이것에 의해 어떻게 변화되는지를 해석한다. 본 연구에서 제안된 방법을 시험계통에 적용하여 그 유용성을 검증하였다.

• Journal of Ship and Ocean Technology
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• 제10권2호
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• pp.37-44
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• 2006

The erection in shipbuilding is the process to assemble all the blocks one by one in certain order and requires more leveled and efficient schedule than other processes do. However, erection schedule includes too many constraints to be systemized with simple programs and constraints are changed frequently. These difficulties make it rare to find automatic erection schedule generation system with load leveling ability. In this paper, a CSP (Constraint Satisfaction Problem)-based load leveling algorithm using a maximum load diminution technique is proposed and applied to the block erection scheduling of a dock in a shipyard. The result shows that it performs better than currently used scheduling method based on empirical logics. The maximum load of welding length and crane usage are reduced by 31.63% and 30.00% respectively. The deviation of resource usage amount also decreases by 8.93% and 7.51%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5574-5591
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• 2017

Inspired by the idea of Artificial Immune System, many researches of wireless sensor network (WSN) intrusion detection is based on the artificial intelligent system (AIS). However, a large number of generated detectors, black hole, overlap problem of NSA have impeded further used in WSN. In order to improve the anomaly detection performance for WSN, detector generation mechanism need to be improved. Therefore, in this paper, a Differential Evolution Constraint Multi-objective Optimization Problem based Negative Selection Algorithm (DE-CMOP based NSA) is proposed to optimize the distribution and effectiveness of the detector. By combining the constraint handling and multi-objective optimization technique, the algorithm is able to generate the detector set with maximized coverage of non-self space and minimized overlap among detectors. By employing differential evolution, the algorithm can reduce the black hole effectively. The experiment results show that our proposed scheme provides improved NSA algorithm in-terms, the detectors generated by the DE-CMOP based NSA more uniform with less overlap and minimum black hole, thus effectively improves the intrusion detection performance. At the same time, the new algorithm reduces the number of detectors which reduces the complexity of detection phase. Thus, this makes it suitable for intrusion detection in WSN.

• Geomechanics and Engineering
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• 제1권2호
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• pp.121-142
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• 2009

The paper deals with the applications of spectral finite element method to the dynamic analysis of framed foundations supporting high speed machines. Comparative performance of approximate dynamic stiffness methods formulated using static stiffness and lumped or consistent or average mass matrices with the exact spectral finite element for a three dimensional Euler-Bernoulli beam element is presented. The convergence of response computed using mode superposition method with the appropriate dynamic stiffness method as the number of modes increase is illustrated. Frequency proportional discretisation level required for mode superposition and approximate dynamic stiffness methods is outlined. It is reiterated that the results of exact dynamic stiffness method are invariant with reference to the discretisation level. The Eigen-frequencies of the system are evaluated using William-Wittrick algorithm and Sturm number generation in the $LDL^T$ decomposition of the real part of the dynamic stiffness matrix, as they cannot be explicitly evaluated. Major's method for dynamic analysis of machine supporting structures is modified and the plane frames are replaced with springs of exact dynamic stiffness and dynamically flexible longitudinal frames. Results of the analysis are compared with exact values. The possible simplifications that could be introduced for a typical machine induced excitation on a framed structure are illustrated and the developed program is modified to account for dynamic constraint equations with a master slave degree of freedom (DOF) option.