• Journal of the Korea Society of Computer and Information
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• v.15 no.9
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• pp.47-55
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• 2010

Linear constraint satisfaction optimization problem is a kind of combinatorial optimization problem involving linearly expressed objective function and complex constraints. Integer programming is known as a very effective technique for such problem but require very much time and memory until finding a suboptimal solution. In this paper, we propose a method to improve the search performance by integrating local search and integer programming. Basically, simple hill-climbing search, which is the simplest form of local search, is used to solve the given problem and integer programming is applied to generate a neighbor solution. In addition, constraint programming is used to generate an initial solution. Through the experimental results using N-Queens maximization problems, we confirmed that the proposed method can produce far better solutions than any other search methods.

• Computational Structural Engineering
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• v.9 no.3
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• pp.169-177
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• 1996

The focus of this study is on the problem of the design of structure of undetermined topology. This problem has been regarded as being the most challenging of structural optimization problems, because of the difficulty of allowing topology to change. Conventional approaches break down when element sizes approach to zero, due to stiffness matrix singularity. In this study, a novel nonlinear programming formulation of the topology problem is presented. Its main feature is the ability to account for topology variation through zero element sizes. Stiffness matrix singularity is avoided by embedding the equilibrium equations as equality constraints in the optimization problem. Although the formulation is general, two dimensional plane elasticity examples are presented. The design problem is to find minimum weight of a plane structure of fixed geometry but variable topology, subject to constraints on stress and displacement. Variables are thicknesses of finite elements, and are permitted to assume zero sizes. The examples demonstrate that the formulation is effective for finding at least a locally minimal weight.

• Journal of the Korea Computer Graphics Society
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• v.12 no.3
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• pp.13-20
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• 2006

모바일 환경에서 고급 그래픽스 기술을 적용하고자 하는 시도로 최근 3D 그래픽 엔진을 탑재한 단말기가 출시되고 있다. 이 단말기는 OpenGL ES 1.x을 기준으로 고정된 파이프라인을 통해 그래픽 연산을 처리하고 있으므로 사용자가 다양한 그래픽 표현을 수행하는데 제약이 따른다. 최근 PC 환경의 그래픽 엔진에서는 고정 기능의 파이프라인이 아닌 프로그래밍 가능한 파이프라인을 제공하여 기존 고정 파이프라인에서 불가능했던 유연한 그래픽스 기술을 제공하고 있다. PC환경의 프로그래밍 가능한 파이프라인은 DirectX와 OpenGL 그래픽 라이브러리에 의해 제공되고 있지만, 모바일 환경에서는 이를 지원하기 위한 관련 제품이 아직 출시되지 않고 있는 상태이다. 본 논문에서는 2005년 9원에 발표된 프로그레밍 가능한 그래픽스 파이프라인에 대한 표준인 OpenGL ES 2.0에 기반한 효율적인 셰이더 구조와 이 의 구동방식을 제시한다. 본 연구는 PC상에서 소프트웨어로 개발되었고, 연구 결과는 그래픽스 하드웨어 설계를 위한 검증용으로 사용될 수 있을 뿐 아니라 응용 프로그래머의 모바일 콘텐츠 제작을 위하여 활용될 수 있다.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.12
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• pp.859-866
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• 2006

Grid portal services provide more flexible research environment by overcoming time and space limit of existing application-based grid services. However user's requirements such as user interfaces are not clear during development cycle and changed frequently. Therefore it is necessary to reduce the cost for creating and maintaining user interfaces of grid services. In this paper, we suggest an object-oriented user control model which allows easier development of user interfaces and increases code reusability by abstracting objects from presentation layer of web. In this model, structure of presentation pages can be described more clearly and implementation of actions is simple and easy.

• Journal of Practical Engineering Education
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• v.7 no.2
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• pp.97-105
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• 2015

In this paper, we have selected physical computing as the focused learning elements with the PBL-based programming instruction method. Students experienced physical computing by using Arduino. Development of robot using Arduino can create an effective educational environment and also provide solutions for lack of environmental conditions, such as time or spatial factor restrictions and excessive expense issues; these are major obstacles to developing robot programming education. Finally, we analyzed the effects on growth of student's logical thinking and problem solving abilities by demonstrating the Arduino application courseware to the field of education.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.11
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• pp.771-781
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• 2022

Sequential convex programming based performance analysis of the designed UAV is performed. The nonlinear optimization problems generated by aerodynamics are approximated to socond order program by discretization and convexification. To improve the performance of the algorithm, the solution of the relaxed problem is used as the initial trajectory. Dive trajectory optimization problem is analyzed through iterative solution procedure of approximated problem. Finally, the maximum final velocity according to the performance of the actuator model was compared.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.530-532
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• 2021

This paper deals with AI education service that enables developers who have completed basic programming education to program in C/C++ language in order to learn big data and artificial intelligence. In addition, a customized development environment configuration system according to the development environment and how the user implements and tests artificial intelligence are explained. And also it has a function to check the effect on artificial intelligence through manipulation of various internal parameters. It is expected that it will be possible to develop artificial intelligence education services without language restrictions through networks in the future.

• The KIPS Transactions:PartA
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• v.14A no.2
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• pp.77-84
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• 2007

The intima media thickness(IMT) of the carotid artery from B mode ultrasound images has recently been proposed as the most useful index of individual atherosclerosis and can be used to predict major cardiovascular events. Ultrasonic measurements of the IMT are conventionally obtained by manually tracing interfaces between tissue layers. The drawbacks of this method are the inter and intra observer variability and its inefficiency. In this paper, we present a multiresolution snake method combined with the dynamic programming, which overcomes the various noises and sensitivity to initialization of conventional snake. First, an image pyramid is constructed using the Gaussian pyramid that maintains global edge information with smoothing in the images, and then the boundaries are automatically detected in the lowest resolution level by minimizing a cost function based on dynamic programming. The cost function includes cost terms which are representing image features and geometrical continuity of the vessel interfaces. Since the detected boundaries are selected as initial contour of the snake for the next level, this automated approach solves the problem of the initialization. Moreover, the proposed snake improves the problem of converging th the local minima by defining the external energy based on multiple image features. In this paper, our method has been validated by computing the correlation between manual and automatic measurements. This automated detection method has obtained more accurate and reproducible results than conventional edge detection by considering multiple image features.

• Journal of Korean Association for Spatial Structures
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• v.8 no.4
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• pp.47-55
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• 2008

This paper deals with basic theories and some numerical results on structural optimization for geodesic dome. First of all, the space efficiency of geodesic dome is investigated by using the ratio of icosahedron's surface area to the internal volume enclosed by it. The procedure how to create the geodesic dome is also provided in systematic way and implemented and utilized into the design optimization code ISADO-OPT. The mathematical programming technique is introduced to find out the optimum pattern of member size of geodesic dome against a point load. In this study, total weight of structure is considered as the objective function to be minimized and the displacement occurred at loading point and member stresses of geodesic dome are used as the constraint functions. The finite difference method is used to calculate the design sensitivity of objective function with respect to design variables. The SLP, SQP and MFDM available in the optimizer DoT is used to search optimum member size patterns of geodesic dome. It is found to be that the optimum member size pattern can be efficiently obtained by using the proposed design optimization technique and numerical results can be used as benchmark test as a basic reference solution for design optimization of dome structures.

• Journal of Korea Multimedia Society
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• v.7 no.7
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• pp.976-984
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• 2004

C# and .NET platform in Microsoft Corp. has been developed to meet the needs of programmers, and cope with Java and JVM platform of Sun Microsystems. After compiling, a program written in .NET language is converted to MSIL code, and also executed by .NET platform but not in JVM platform. Java, one of the most widely used programming languages recently, is the language invented by James Gosling at Sun Microsystems, which is the next generation language independent of operating systems and hardware platforms. Java source code is compiled into bytecode as intermediate code independent of each platform by compiler, and also executed by JVM. This paper presents the MSIL-to-Bytecode intermediate language translator which enables the execution of the program written in .NET language such as C or C# in JVM(Java Virtual Machine) environment, translating MSIL code produced by compiling .NET program into java bytecode. This work provides an environment for programmers to develop application programs without limitations of programming languages.