• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.4
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• pp.226-234
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• 2004

A rapid Prototyping system that laser-cuts and laminates thick layers can fabricate 3D objects promptly with a variety of materials. Building such a system must consider the surface distortions due to both vertical-cut layers and triangular surfaces. We developed a tangential layer-cutting algorithm by rearranging tangential lines such that they reconstruct 3D surfaces more closely and also constitute smoother laser trajectories. An energy function that reflects the surface-closeness with the tangential lines was formulated and then the energy was minimized by a gradient descent method. Since this simple method tends to cause many local minima for complex 3D objects, we tried to solve this problem by adding a simulated annealing process to the proposed method. To view and manipulate 3D objects, we also implemented a 3D visual environment. Under this environment, experiments on various 3D objects showed that our algorithm effectively approximates 3D surfaces and makes laser-trajectory feasibly smooth.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.15 no.26
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• pp.13-19
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• 1992

MODM(multiobjective decision-making)problem is very complex system for the analysist and decision maker. Therefore, it requires suitable MODM method to solve multiobjective decision-making problem. This paper presents an interactive fuzzy decision making method for solving multiobjective nonlinear programming problems with fuzzy goals and $\alpha$-cut set of fuzzy numbers. In our interactive method, if the decision maker specifies the degree $\alpha$of the objective value and the imprecise goals, λ-mux problem is solved. To examplify the proposed method, an interactive computer programming written in FORTRAN and an illustrate numerical example along with computer outputs are presented.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.3
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• pp.30-39
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• 2010

This paper considers a problem of optimizing torch paths to cut stock plates nested with open contours. For each contour, one of the two ending points is to be selected as a starting point of cutting with the other being the exit point. A torch path is composed of a single depot and a series of starting and ending points of contours to be cut. The torch path optimization problem is shown to be formulated as an extended version of the standard travelling salesman problem. To solve the problem, a hybrid genetic algorithm with the local search of torch paths is proposed. The genetic algorithm is tested for hypothetical problems whose optimal solutions are known in advance due to the special structure of them. The computational results show that the algorithm generates very near optimal solutions for most cases of the test problems, which verifies the validity of the algorithms.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.1
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• pp.79-84
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• 2009

In this paper, a best-first branch and bound algorithm based upon the bottom-up approach for the unweighted unconstrained two-dimensional cutting problem is proposed to find the optimal solution to the problem. The algorithm uses simple and effective methods to prevent constructing duplicated patterns and reduces the searching space by dividing the branched node set. It also uses a efficient bounding strategy to fathom the set of patterns. Computational results are compared with veil-known exact algorithms and demonstrate the efficiency of the proposed algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.10
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• pp.1029-1034
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• 2006

In this paper, the tracking control of an automatic pipe cutting robot, called APCROM, with a magnetic binder is studied. Using magnetic force APCROM, a wheeled robot, binds itself to the pipe and executes unmanned cutting process. The gravity effect on the movement of APCROM varies as it rotates around the pipe laid in the gravitational field. In addition to the varying gravity effect other types of nonlinear disturbances including backlash in the driving system and the slip between the wheels of APCROM and the pipe also cause degradation in the cutting process. To maintain a constant velocity and consistent cutting performance, the authors adopt a repetitive learning controller (MRLC), which learns the required effort to cancel the tracking errors. An angular-position estimation method based on the MEMS-type accelerometer is also used in conjunction with MRLC to compensate the tracking error caused by slip at the wheels. Experimental results verify the effectiveness of the proposed control scheme.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.170-170
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• 1993

유전독성물절외 검출과 평가에 용이하게 사용할 수 있는 모델 시스템의 개발 및 DNA 회복기작을 규명할 목적으로 수종의 돌연변이, 발암원을 이용하여 배양 포유동물세포 및 어류세포에서 세포생존률, DNA 합성 및 복제억제의 양상 등을 비교 분석하였다. MMS및 MNNG 와 같은 알칼라제는 CHO 세포에서 유의한 DNA 합성저해, DNA 복재억제, DNA 단사절단 및 비주기성 DNA 합성률의 증가를 유발하였다. Benzo(a)pyrene과 3-methylcholanthrene좌 같은 DNA 상해 전구물질의 경우 유전독성 여부의 판정에는 반드시 S-9/15과 같은 대사활성계 또는 mouse embryonic fibroblast와 같은 대사 활성능이 있는 세포와의 co-culture system들이 필요함을 확인하였으며, 이들에 의한 DNA 상해와 복재억제 유도의 작용양상은 자외선의 작용양상과 유사하였다. 배양 어류세포에서 자외선에 의한 세포생존율의 측정, 광재활성능의 분석 및 자외선에 의해 유발된 피리미딘 이량체 절제능 검토 및 DNA 합성 저해능의 결과를 분석함으로써 유전독성 평가를 위한 모델 시스템 구축의 기초결과를 얻었다.

• The Optical Journal
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• s.124
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• pp.28-32
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• 2009

초정밀 초고속 레이저 가공공정 및 장비는 유연소재의 태양전지, 인쇄전자소자(printed electronics devices)의 초고속 절단공정, 고기능 다기능 모바일 기기용 고부가 PCB의 초정밀 초고속 레이저 드릴링 및 복합 유연 가공 등에 적용된다. 최근 레이저 가공기 연구개발 패러다임은 레이저 의존형 장비 개발에서 레이저 맞춤형 장비 개발로 변화되고 있다. 즉, 수입된 레이저 발진기 및 광학기기를 사용하여 레이저 공정 및 장비를 개발하는 방식에서 벗어나, 개발하고자 하는 공정 및 장비에 최적화된 레이저 발진기 개발을 병행하는 것이다. 이러한 상황에서 최근 지식경제부 산업원천기술개발사업으로 신개념 레이저 기반 초정밀 초고속 가공시스템 개발이 착수되었으며, 본 고에서는 이에 대한 전반적인 내용들 소개하고자 한다.

• Transactions of the Society of Information Storage Systems
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• v.6 no.1
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• pp.18-24
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• 2010

The performance of the speech recognition mainly depends on uncertain factors such as speaker's conditions and environmental effects. The present study deals with the speech recognition of a number of multi-syllable isolated Korean words using soft computing techniques such as back-propagation neural network, fuzzy inference system, and fuzzy neural network. Feature patterns for the speech recognition are analyzed with 12th order thirty frames that are normalized by the linear predictive coding and Cepstrums. Using four models of speech recognizer, actual experiments for both single-speakers and multiple-speakers are conducted. Through this study, the recognizers of combined fuzzy logic and back-propagation neural network and fuzzy neural network show the better performance in identifying the speech recognition.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.1
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• pp.135-142
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• 2006

The package loading process of tile lumbering industry is an operation that after a pair of workers binds three or six lumber into a unit and cut the both ends of the lumber, carry and pack and load the weight cargo of 30-50kg. The package loading process causes lots of noise and wood dust when the lumber are cut and brings about the main cause of the musculoskeletal disorder when workers carry the heavy goods. Therefore, we developed the monolithic package loading equipment cutting both ends that is enable to improve the working method and environments of the existing package loading process. The noise and wood dust were reduced by developing the device and the main cause of shirking duties on working place was solved by preventing the musculoskeletal disorder and improving the working environments as excluding the work of carrying heavy goods.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.62
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• pp.21-32
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• 2001

The two-dimensional guillotine cutting problem is to maximize sum of piece profits that cut from one stock rectangle and widely applied in the industry. The branch-and-bound method for this problem uses complementarily several upper bounds(the Gilmore and Gomoryp[8]'s two-dimensional knapsack function and the Hifi and Zissimopoulos[10]'s method using one-dimensional knapsack problem, etc) to reduce the number of searched nodes. These upper bounds has a shortcoming that does not consider the bound and layout of pieces simultaneously. In this paper, we propose an efficient upper bound which can complement the shortcoming of existing upper bounds. The proposed upper bound needs less memory spaces and computing time. Computational results show that the proposed upper bound significantly contribute to reduce the computational amount of time and number of searched nodes in tree.