• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1589-1590
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• 2006

A method to determine functional relationships between the variable physical dimensions of an antenna and the antenna performance characteristics is presented. By applying multi-expression programming (MEP) to this data set, optimization with regard to a given criteria can be subsequently performed on the functions instead of performing repealed electromagnetic simulations. The functionals are trained on an initial population of simulation samples and refined using a point-wise error estimate to identify design parameters for subsequent samples. Additionally, the depth of the MEP tree is adjusted for increased accuracy as the data set is deemed sufficient.

• Structural Engineering and Mechanics
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• 제36권6호
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• pp.759-783
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• 2010

In this paper, compressive strength of carbon fiber reinforced polymer (CFRP) confined concrete cylinders is formulated using a hybrid method coupling genetic programming (GP) and simulated annealing (SA), called GP/SA, and a robust variant of GP, namely multi expression programming (MEP). Straightforward GP/SA and MEP-based prediction equations are derived for the compressive strength of CFRP-wrapped concrete cylinders. The models are constructed using two sets of predictor variables. The first set comprises diameter of concrete cylinder, unconfined concrete strength, tensile strength of CFRP laminate, and total thickness of CFRP layer. The most widely used parameters of unconfined concrete strength and ultimate confinement pressure are included in the second set. The models are developed based on the experimental results obtained from the literature. To verify the applicability of the proposed models, they are employed to estimate the compressive strength of parts of test results that were not included in the modeling process. A sensitivity analysis is carried out to determine the contributions of the parameters affecting the compressive strength. For more verification, a parametric study is carried out and the trends of the results are confirmed via some previous studies. The GP/SA and MEP models are able to predict the ultimate compressive strength with an acceptable level of accuracy. The proposed models perform superior than several CFRP confinement models found in the literature. The derived models are particularly valuable for pre-design purposes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권2호
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• pp.288-307
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• 2013

This paper formulates resource allocation for decode-and-forward (DF) relay assisted multi-cell orthogonal frequency division multiple (OFDM) networks as an optimization problem taking into account of inter-cell interference and users fairness. To maximize the transmit rate of system we propose a joint interference coordination, subcarrier and power allocation algorithm. To reduce the complexity, this semi-distributed algorithm divides the primal optimization into three sub-optimization problems, which transforms the mixed binary nonlinear programming problem (BNLP) into standard convex optimization problems. The first layer optimization problem is used to get the optimal subcarrier distribution index. The second is to solve the problem that how to allocate power optimally in a certain subcarrier distribution order. Based on the concept of equivalent channel gain (ECG) we transform the max-min function into standard closed expression. Subsequently, with the aid of dual decomposition, water-filling theorem and iterative power allocation algorithm the optimal solution of the original problem can be got with acceptable complexity. The third sub-problem considers dynamic co-channel interference caused by adjacent cells and redistributes resources to achieve the goal of maximizing system throughput. Finally, simulation results are provided to corroborate the proposed algorithm.

• 서비스연구
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• 제6권2호
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• pp.175-184
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• 2016

오락적 기능을 가지고 있는 교육용 컴퓨터 게임 서비스는 학생들이 학습에 대한 흥미를 높일 수 있도록 도와주는 매력적인 도구로 활용되고 있다. 특히, 수학 과목은 교육용 컴퓨터 게임 서비스가 가장 효과적으로 적용될 수 있는 대표적인 교과목이다. 기존에 개발된 게임 서비스는 대부분 단일 사용자 혹은 2명이 게임에 참여하는 형태이며 문제로 제시된 수식의 답을 단순히 찾는 방식으로 진행된다. 본 논문에서는 교육용 게임 서비스 요구 사항을 준수하고 특히 TCP/IP 소켓 프로그래밍 기술을 기반으로 여러 학습자가 동시에 게임에 참가 할 수 있는 멀티플레이형 게임 서비스를 설계 및 구현하였다. 또한, 수 감각의 신장을 유도하기 위해 단순히 수식의 답만 구하는 것이 아니라 학습자 스스로 여러 수식을 합성하고 선택 할 수 있도록 게임 규칙을 설계하여 적용하였다. 마지막으로 제안 게임 서비스를 교육용 게임 서비스 요구사항에 따라 비교하여 적합성을 확인하였다.

• 한국경영과학회지
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• 제23권3호
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• pp.27-36
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• 1998

This work has improved the method of Kim and Gal's (6) in that of requiring less response of the DM(decision maker) and ease of reply. The underlying notion is the MCDC(maximally changeable dominance cone) for describing all efficient solutions under the particular preference structure. According to the DM's partial preference expression, enlarging the MCDC is achieved, which results in reducing the solutions needed to take into consideration. The cone generators corresponding to the DM's response are added to the MCDC, which results the MCDC is enlarged. Adopting the scheme of pairwise comparison as a means of acquiring preference attitude, an improved interactive method is proposed. And also, a scheme of choosing a reference point is suggested to achieve the computational efficiency.

• Geomechanics and Engineering
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• 제30권6호
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• pp.551-564
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• 2022

Fragmenting the rock mass is considered as the most important work in open-pit mines. Ground vibration is the most hazardous issue of blasting which can cause critical damage to the surrounding structures. This paper focuses on developing an explicit model to predict the ground vibration through an multi objective evolutionary polynomial regression (MOGA-EPR). To this end, a database including 79 sets of data related to a quarry site in Malaysia were used. In addition, a gene expression programming (GEP) model and several empirical equations were employed to predict ground vibration, and their performances were then compared with the MOGA-EPR model using the mean absolute error (MAE), root mean square error (RMSE), mean (𝜇), standard deviation of the mean (𝜎), coefficient of determination (R²) and a20-index. Comparing the results, it was found that the MOGA-EPR model predicted the ground vibration more precisely than the GEP model and the empirical equations, where the MOGA-EPR scored lower MAE and RMSE, 𝜇 and 𝜎 closer to the optimum value, and higher R² and a20-index. Accordingly, the proposed MOGA-EPR model can be introduced as a useful method to predict ground vibration and has the capacity to be generalized to predict other blasting effects.

• International Journal of Advanced Culture Technology
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• 제6권2호
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• pp.107-116
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• 2018

In the past, design has been recognized as a means to determine colors, shapes, and functions Recently, however, it has been accepted in a wider sense, namely designing the entire service, including product and user experience design. In this way, in addition to creativity and expressive power that designers have as their main competence, according to the expansion of this design object, designers are required to have comprehensive abilities in related fields and accompanying technical professional abilities. If designing as a technology application as a direction toward this situation, design education can be carried out by approaching technology as a method of expression or design subject. It can also be an effective alternative towards improving the understanding of technology. Meanwhile, many small microcontroller board products with advanced functions and multi-functional specialized programming integrated development environments (IDEs) are becoming widespread due to their open source, low cost, and scalable features. However, students in the design department who lack the basic knowledge of science and engineering have difficulties learning, which requires considerable time and is required for practical use. From this point of view, we have made advancements in the technical understanding of design education by conducting fundamental research to the effectiveness of microcontroller-based prototyping tools as means of expression. We also conducted basic education of microcontroller boards for a certain period of time on students who majored in design in conjunction with the basic survey and investigated the obstacle factors using a questionnaire. Through these surveys, we have confirmed the necessity of designing microcontroller boards of low difficulty, which simplify the coding process that can act as a barrier in difficulty for design students to apply smoothly in design education. In addition, we intend to carry out a basic study on the guideline of microcontroller design for design education and composition of education programs.