• Journal of Communications and Networks
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• 제7권4호
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• pp.471-477
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• 2005

This paper proposes an efficient constraint-based optimization model for the design of 3G mobile networks, such as universal mobile telecommunications system (UMTS). The model concerns about finding a set of sites for locating radio network controllers (RNCs) from a set of pre-defined candidate sites, and at the same time optimally assigning node Bs to the selected RNCs. All these choices must satisfy a set of constraints and optimize an objective function. This problem is NP-hard and consequently cannot be practically solved by exact methods for real size networks. Thus, this paper proposes a hybrid search strategy for tackling this complex and combinatorial optimization problem. The proposed hybrid search strategy is composed of three phases: A constraint satisfaction method with an embedded problem-specific goal which guides the search for a good initial solution, an optimization phase using local search algorithms, such as tabu algorithm, and a post­optimization phase to improve solutions from the second phase by using a constraint optimization procedure. Computational results show that the proposed search strategy and the model are highly efficient. Optimal solutions are always obtained for small or medium sized problems. For large sized problems, the final results are on average within $5.77\%$ to $7.48\%$ of the lower bounds.

• Current Optics and Photonics
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• 제7권5호
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• pp.529-536
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• 2023

The Morlet wavelet transform method is proposed to analyze a single interferogram with spatial carrier frequency that is captured by an optical interferometer. The method can retain low frequency components that contain the phase information of a measured optical surface, and remove high frequency disturbances by wavelet decomposition and reconstruction. The key to retrieving the phases from the low-frequency wavelet components is to extract wavelet ridges by calculating the maximum value of the wavelet transform amplitude. Afterwards, the wrapped phases can be accurately solved by multiple iterative calculations on wavelet ridges. Finally, we can reconstruct the wave-front of the measured optical element by applying two-dimensional discrete cosine transform to those wrapped phases. Morlet wavelet transform does not need to remove the spatial carrier frequency components manually in the processing of interferogram analysis, but the step is necessary in the Fourier transform algorithm. So, the Morlet wavelet simplifies the process of the analysis of interference fringe patterns compared to Fourier transform. Consequently, wavelet transform is more suitable for automated programming analysis of interference fringes and avoiding the introduction of additional errors compared with Fourier transform.

• 경영과학
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• 제32권1호
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• pp.49-63
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• 2015

This paper investigates an aircraft-target assignment problem in consideration of deconfliction. The aircraft-target assignment problem is the problem to assign available aircrafts and weapons to targets that should be attacked, where the objective function is to minimize the total expected damage of aircrafts. Deconfliction is the way of dividing airspaces for aircraft flight to ensure the safety while performing the mission. In this paper, mixed integer programming model is suggested, where it considers deconfliction between aircrafts. However, the suggested MIP model is non-linear and limited to get solution for large size problem. The 2-phase decomposition model is suggested for efficiency and computation, where in the first phase target area is divided into sectors for deconfliction and in the second phase aircrafts and weapons are assigned to given targets for minimizing expected damage of aircraft. The proposed decomposition model shows outperforms the model developed for comparison in the computational experiment.

• 한국안광학회지
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• 제10권4호
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• pp.305-312
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• 2005

분 논문에서는 Lohmann 방법과 FFT (fast Fourier transform)를 사용하여 홀로그램을 제작하였다. 먼저 수학적으로 정의되는 물체의 $128{\times}128$로 표본화된 점들에 대한 복소 파면을 FFT 연산으로 구하였다. 그리고 Lohmann의 방법을 사용하여 각각의 표본점에 대한 복소 파면의 진폭과 위상을 홀로그램 정보로 바꾸었다. PC와 레이저 프린터를 용하여 홀로그램 도면을 그렸으며, 그 도면을 사진 축소하여 CGH(computer generated holograms) 필름을 제작하였다. 헬륨-네온 레이저와 역퓨리에 변환 광학계를 사용하여 수학적으로 정의되는 물체의 홀로그램 상을 재생하였다. $32{\times}32$, $64{\times}64$, $128{\times}128$의 표본수, random 위상의 적용 여부, 진폭 절단 및 CGH 필름의 표백 정도에 따라 변화하는 홀로그램 상의 특성을 조사하였다. 이 실험을 통하여 우수한 홀로그램 상을 재생할 수 있는 최적 조건과 홀로그램 상에서 스페클 잡음을 줄일 수 있는 최적 조건을 얻을 수 있었다. 2진 위상 홀로그램을 프로그램하기 위하여 Lohmann의 알고리즘을 MS Visual BASIC 6.0으로 구현하였다.

• Structural Engineering and Mechanics
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• 제47권3호
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• pp.401-419
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• 2013

In this study, the efficiency of adaptive neuro-fuzzy inference system (ANFIS) and genetic expression programming (GEP) in predicting the effects of infill walls on base reactions and roof drift of reinforced concrete frames were investigated. Current standards generally consider weight and fundamental period of structures in predicting base reactions and roof drift of structures by neglecting numbers of floors, bays, shear walls and infilled bays. Number of stories, number of bays in x and y directions, ratio of shear wall areas to the floor area, ratio of bays with infilled walls to total number bays and existence of open story were selected as parameters in GEP and ANFIS modeling. GEP and ANFIS have been widely used as alternative approaches to model complex systems. The effects of these parameters on base reactions and roof drift of RC frames were studied using 3D finite element method on 216 building models. Results obtained from 3D FEM models were used to in training and testing ANFIS and GEP models. In ANFIS and GEP models, number of floors, number of bays, ratio of shear walls and ratio of infilled bays were selected as input parameters, and base reactions and roof drifts were selected as output parameters. Results showed that the ANFIS and GEP models are capable of accurately predicting the base reactions and roof drifts of RC frames used in the training and testing phase of the study. The GEP model results better prediction compared to ANFIS model.

• 한국콘텐츠학회논문지
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• 제5권3호
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• pp.133-140
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• 2005

게임 개발 환경을 개선하기 위해 고려해야할 중요한 사항 중 하나가 게임을 구현하기 위한 언어이다. 현재 게임을 개발하기 위해 설계되어있는 전용 언어는 부족한 상황이다. 따라서 게임개발은 범용의 프로그래밍 언어를 이용하여 직접적으로 엔진을 모델링하여 구현하고 있다. 따라서 개발자는 쉽게 게임을 개발하기 어려우며 엔진레벨에서 프로그래밍을 해야한다. 엔진을 잘 이해하지 못한 환경에서 게임을 개발하는 것은 상당히 어려운 일이다. 개발자와 기획자는 쉽게 게임을 개발하기 위해 기획자 측면에서 사용할 수 있는 추상화된 상위언어를 사용하고자 한다. 그리고 기획자와 개발자 사이의 의사교환을 위한 도구도 없는 상황이다. 그러므로 본 연구에서는 추상화된 엔진레벨에서 모델링이 가능한 스크립트 언어를 정의하였다. 그리고 추상화된 고수준의 언어를 이용하여 게임을 개발할 수 있는 통합환경을 구축하였다. 스크립트 언어는 라른 속도로 게임을 개발할 수 있도록 하였다. 따라서 개발자는 엔진레벨이 아닌 기획자와 게임을 개발할 수 있다. 또한 기획자와 개발자는 통합환경을 이용하여 스켈레톤 게임을 만들 수 있기 때문에 의사교환 도구로 이용할 수 있다.

• 한국식품과학회지
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• 제4권3호
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• pp.213-223
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• 1972

This paper chose the methods of methylesterification of the use of methoxide, the mixture solution of methanol-benzen-sulfuric acid in transesterification of the fat in cow's milk and modified powder milk and separated by gas liquid chromatography with F.F.A.P., D.E.G.A. as liquid phase. Quantitative analysis of the fatty acid of milk fat in cow's milk and modified powder milk was determined by gas liquid chromatography using the method of temperature programming which should be used to obtain satisfactory separation of short chain fatty acid on the chromatogram. It was found that the fatty acid composition of cow's milk and modified powder milk are all the major fatty acid of milk fat obtained by GLC analysis. Main components was found to be from butyric acid to arachidonic acid showing Fig. 3, 4, 5 and Table 4, 5, 6, 7, 8, 9.

• 산업식품공학
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• 제23권2호
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• pp.87-93
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• 2019

공기 주입식 스팀-에어 레토르트 내에서 스팀온도, 내부가압, CUT 등의 공정변수가 레토르트 내부의 온도 균일성에 미치는 영향을 평가하였다. 고온살균(121℃)이 저온살균(82℃) 보다 공정구간동안 온도분포가 더 균일하고 안정적이었다. 내부 가압이 클수록 저온살균조건의 공정에서는 온도분포가 안정적이었고, 이와 반대로 고온살균조건의 공정에서 온도분포가 더 불균일한 것으로 나타났다. 승온구간을 조절한 경우에는 레토르트 내의 온도분포에는 유의적인 차이를 나타내지 않았다. 공정구간동안 레토르트 내부에서 냉점은 수직방향 1층의 위로 확인되었고, 수평방향에서는 맨 뒤쪽 중앙 부분이 가장 높은 온도를 유지하여 공정 동안 이 위치들을 주의를 할 필요가 있었다. 또한 레토르트 내부의 양 옆 위치가 다른 위치에 비해 특히 온도분포가 불안정한 것으로 확인되었으므로 레토르트 가공 공정에서 주의해야 할 것으로 판단되었다.

• Steel and Composite Structures
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• 제22권5호
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• pp.1163-1192
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• 2016

This paper presents the cost optimization of a composite I beam floor system, designed to be made from a reinforced concrete slab and steel I sections. The optimization was performed by the mixed-integer non-linear programming (MINLP) approach. For this purpose, a number of different optimization models were developed that enable different design possibilities such as welded or standard steel I sections, plastic or elastic cross-section resistances, and different positions of the neutral axes. An accurate economic objective function of the self-manufacturing costs was developed and subjected to design, resistance and deflection (in)equality constraints. Dimensioning constraints were defined in accordance with Eurocode 4. The Modified Outer-Approximation/Equality-Relaxation (OA/ER) algorithm was applied together with a two-phase MINLP strategy. A numerical example of the optimization of a composite I beam floor system, as presented at the end of this paper, demonstrates the applicability of the proposed approach. The optimal result includes the minimal produced costs of the structure, the optimal concrete and steel strengths, and dimensions.

• ETRI Journal
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• 제18권4호
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• pp.265-286
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• 1997

This paper presents a new software development environment that supports an integrated methodology for covering all phases of software development and gives integrated methods with tools for ITUT (Telecommunication Standardization Section of the International Telecommunication Union) languages. The design of the environment to improve software productivity and quality is based on five main concepts: 1) formal specifications based on SDL (Specification and Description Language) and MSC (Message Sequence Charts) in the design phase, 2) verification and validation of those designs by tools, 3) automatic code generation and a safe separate compilation scheme based on CHILL (CCITT High-Level Language) to facilitate programming-in-the-many and programming-in-the-large. 4) debugging of distributed real-time concurrent CHILL programs, and 5) simulation of application software for integrated testing on the host machine based on CHILL. The application results of the environment compared with other approaches show that the productivity is increased by 19 % because of decreasing implementation and testing cost, and the quality is increased by 83 % because of the formal specifications with its static and dynamic checking facilities.