• Journal of Engineering Education Research
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• v.10 no.3
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• pp.109-124
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• 2007

With the advance of the Internet and computing technologies, e-learning is now a hot issue worldwide for providing the effective learning on the cyber-space. However, most of existing e-learning contents have been developed mainly based on text, including simple multimedia elements such as images, animations, and voices. This paper suggests a method effective for the computer programming e-learning. The method is based on program visualization using flowcharts. It features the stepwise hierarchical program visualization on the level of statements, the flowchart based visualization for control constructs of languages, visualization over whole programs, visualization compared with source codes, and interaction with users. Finally, we implement a system to realize the suggested method, and execute it for an example program.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.57-65
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• 2014

This paper presents a framework that is based on a reconfigurable macro-model of current-mode logic (CML) high-speed digital circuits enabling equation-based design optimization. The proposed macro-model is compatible with geometric programming, thereby enabling constraint-driven top-level power optimization. The proposed optimization framework is applied to a design of CML based serial-link transmitter with user-defined design specifications as an example of high speed digital circuits using 45nm and 90nm CMOS technology. The proposed optimization framework can derive a design with optimal power efficiency for given transistor technology nodes.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.7
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• pp.775-787
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• 2010

Unlike general-purpose CPUs, the GPUs have been specialized as many-core streaming processors, and are frequently replacing the CPUs in an increasing range of computations thanks to their outstanding parallel computing capacity. In order to respond to such trend, NVIDIA has recently issued a new parallel computing architecture called CUDA(Compute Unified Device Architecture), offering a flexible GPU programming environment for GPGPU(General Purpose GPU) computing. In general, when programmers use the CUDA API, they should clearly understand many aspects of GPU's computing architecture to produce efficient parallel software. In this article, we explain several optimization techniques for CUDA programming that we have verified through a lot of experiment and trial and error, and review how those techniques affect the performance of code execution. In particular, we use a specific problem as an example to analyze several elements that affect performances, such as effective accesses to hierarchical memory system, processor occupancy, and latency hiding. In conclusion, we present several directions that may be utilized effectively in CUDA-based parallel programming.

• Korean Journal of Computational Design and Engineering
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• v.12 no.3
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• pp.220-232
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• 2007

Current geometric modeling and analysis are commonly based on B-Rep modeling and a finite elements method respectively. Furthermore, it is difficult to represent an object whose material property is heterogeneous using the B-Rep method because the B-Rep is basically used for homogeneous models. In addition, meshes are required to analyze a property of a model when the finite elements method is applied. However, the process of generating meshes from B-Rep is cumbersome and sometimes difficult especially when the model is deformed as time goes by because the topology of deforming meshes are changed. To overcome those problems in modeling and analysis including homogeneous and heterogeneous materials, we suggest a unified modeling and analysis method based on implicit representation of the model using R-function which is suggested by Rvachev. For implicit modeling of an object a distance field is approximated and blended for a complex object. Using the implicit function mesh-free analysis is possible where meshes are not necessary. Generally mesh-free analysis requires heavy computational cost compared to a finite elements method. To improve the computing time of function evaluation, we utilize GPU programming. Finally, we give an example of a simple pipe design problem and show modeling and analysis process using our unified modeling and analysis method.

• Journal of Internet Computing and Services
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• v.5 no.4
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• pp.125-134
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• 2004

Recently a lot of researches on the component-based software product lines and on applying generative programming into software product lines are being performed actively. This paper proposes an automatic component reconfiguration tool that could be applied in constructing the component-based software product lines. Our tool accepts the reuser's requirement via a feature model which is the main result of the domain engineering, and makes the feature configuration from this requirement. Then it generates the source code of the reconfigured component according to this feature configuration. To accomplish this process, the component family in our tool should have the architecture of GenVoca that is one of the most influential generative programming approaches. In addition, XSLT scripts provide the code templates for implementation elements which are the ingredients of the target component. Taking the ‘Bank Account' component family as our example, we showed that our component reconfiguration tool produced automatically the component source code that the reuser wants to create. The result of this paper would be applied extensively for creasing the productivity of building the software product lines.

• Journal of the Korea Society of Computer and Information
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• v.15 no.11
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• pp.143-156
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• 2010

Faced with an increase of malicious threats from the Internet as well as local area networks, many companies are considering deploying a security system. To help a decision maker select a suitable security tool, this paper proposed a three-step integrated framework using linear fuzzy regression (LFR) and physical programming (PP). First, based on the experts' estimations on security criteria, analytic hierarchy process (AHP) and quality function deployment (QFD) are employed to specify an intermediate score for each criterion and the relationship among these criteria. Next, evaluation value of each criterion is computed by using LFR. Finally, a goal programming (GP) method is customized to obtain the most appropriate security tool for an organization, considering a tradeoff among the multi-objectives associated with quality, credibility and costs, utilizing the relative weights calculated by the physical programming weights (PPW) algorithm. A numerical example provided illustrates the advantages and contributions of this approach. Proposed approach is anticipated to help a decision maker select a suitable security tool by taking advantage of experts' experience, with noises eliminated, as well as the accuracy of mathematical optimization methods.

• Proceedings of the Korea Database Society Conference
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• 1999.06a
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• pp.95-102
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• 1999

The web-based group collaborative systems are emerging as enterprise-wide information systems. Since data in group collaborative systems are apt to be shared among multiple concurrent users and modified simutaneously by them, the web-based group collaborative systems must support synchronous collaboration in order to provide users with synchronized and consistent views of shared data. This Paper proposes an active web server which can facilitate synchronous collaboration in web-based group collaborative systems. To accomplish such a goal, the active web server manages dependency relationships between shared data and web browsers referencing them and actively propagates changing details of the shared data to all web browsers referencing them. And, this paper examines usefullness and effectiveness of the active web server to apply it to the ball-bearing design example of concurrent engineering design systems. The prototype system of the active web server is developed on a commercial Object-oriented Database Management System (ODBMS) called OBJECTSTORE using the C＋＋ programming language.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 1999.03a
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• pp.95-102
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• 1999

The web-based group collaborative systems are emerging as enterprise-wide information systems. Since data in group collaborative systems are apt to be shared among multiple concurrent users and modified simutaneously by them, the web-based group collaborative systems must support synchronous collaboration in order to provide users with synchronized and consistent views of shared data. This paper proposes an active web server which can facilitate synchronous collaboration in web-based group collaborative systems. To accomplish such a goal, the active web server manages dependency relationships between shared data and web browsers referencing them and actively propagates changing details of the shared data to all web browsers referencing them. And, this paper examines usefullness and effectiveness of the active web server to apply it to the ball-bearing design example of concurrent engineering design systems. The prototype system of the active web server is developed on a commercial Object-oriented Database Management System (ODBMS) called OBJECTSTORE using the C++ programming language.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.3
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• pp.173-181
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• 2016

This paper deals with the single-hoist and multiple-products scheduling problem. Although a mixed integer linear programming model for the problem was developed earlier, a branch-and-bound based heuristic algorithm is proposed in this paper to solve the big-size problems in real situation. The algorithm is capable of handling problems incorporating different product types, jobs in the process, and tank capacities. Using a small example problem the procedure of the heuristic algorithm is explained. To assess the performance of the heuristic we generate a bigger example problem and compare the results of the algorithm proposed in this paper with the optimal solutions derived from the mathematical model of earlier research. The comparison shows that the heuristic has very good performance and the computation time is sufficiently short to use the algorithm in real situation.

• Journal of Creative Information Culture
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• v.5 no.3
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• pp.307-317
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• 2019

This study is an example of the education of block coding and physical computing teaching tool for preservice teachers at the college of education. The students were familiar with coding and improved their coding skills in solving various problems through 'Entry' that support block coding. In addition, the students configured the computing system with various input / output devices of the physical computing teaching tool and controlled things through programming and produced the educational portfolio to experience the whole process of problem analysis, design, implementation, and testing in coding. We applied Flow based coding and Pair programming as the teaching methods, and the results of the survey to measure the effectiveness of the study show that students have a good understanding of the entry and physical computing teaching tool and using the combination of the entry and physical computing teaching tool were more effective in learning than the Entry-only coding. In addition, it was confirmed that the effect of Pair programming applied in the physical computing teaching tool.