• Journal of Digital Contents Society
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• v.14 no.3
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• pp.313-321
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• 2013

In recent, proliferation of mobile smart devices have led to big-data era, the importance of location-based services is increasing due to the exponential growth of trajectory related data. In order to process trajectory data, parallel processing platforms such as cloud computing and MapReduce are necessary. Currently, the researches based on MapReduce are on progress, but due to the MapReduce's properties in using batch processing and simple key-value structure, applying MapReduce framework for real time LBS is difficult. Therefore, in this research we propose a suitable system design on efficient indexing and search techniques for real time service based on detailed analysis on the properties of MapReduce.

• The Mathematical Education
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• v.43 no.2
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• pp.139-149
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• 2004

This study was initiated by the idea to help students to be more ideally educated following the 7th curriculum that seeks the proactive students along with creativity for the 21st century. Mind-map was the main tool throughout the study and this was performed to find answers for the following questions : 1) to examine how students' drawing a mind-map affects their mathematical tendency or emotional aspects (motivation for study, interest, etc); 2) to investigate the types and characteristics of mind-maps that students draw; 3) to analyze advantages and obstacles that they experience during the process of drawing a mind-map and provide some suggestions for overcoming them. The research shows that students were highly motivated by the drawing a mind-map. There are types of mind-maps: tree shape and radial shape, and each shape has its own advantages. But the more important factor for being a good mind-map is where and how each concept is located and connected. Although it is true that drawing a mind-map helped students to see the bigger structure of what they learned, but there are several hardships taken care of. The study suggests to extend the experiment to various levels of students and diverse contents.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.4
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• pp.289-297
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• 2007

Normaly, the map generlization methode has been used for the making of small scale map using a large scale map. The object join methode is consumed of a lots of processing time and the manual process. The object Join technique used in the NGI based on the digital map ver. 1.0 have problems of poor Joining rate and a lots of processing time. This study has improved the object Join technique considering of the geometry and attribute information for the digital map ver. 2.0. Using improved technique increased joining rate of object and reduced the processing time.

• Bulletin of the Korean Mathematical Society
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• v.53 no.4
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• pp.985-1004
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• 2016

We consider the MAP/PH/c/K queue in which blocked customers retry to get service and servers may take vacations. The time interval between retrials and vacation times are of phase type (PH) distributions. Using the method of mean drift, a sufficient condition of ergodicity is provided. A condition for the system to be unstable is also given by the stochastic comparison method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.159-162
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• 2003

The remeshing algorithm using the constrained Delaunay method adapted to the mesh density map is developed. In the finite element simulation of forging process, the numerical error increases as the process goes on. However, it is not desirable to use a uniformly fine mesh in the whole domain. Therefore, it is necessary to reduce the analysis error by constructing locally fine mesh at the region where the error is concentrated such as die corner. In this paper, the point insertion algorithm is used and mesh size is controlled by using a mesh density map constructed with a posteriori error estimation. And an optimized smoothing technique is adapted to have smooth distribution and improve the quality of the mesh.

• Korean Journal of Computational Design and Engineering
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• v.2 no.3
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• pp.161-174
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• 1997

In this paper, the techniques for graphic simulation of material removal process are described. The concepts of the bounding box and base plane are proposed. With these concepts, a real-time shaded display of a Z-map model being milled by a cutting tool following an NC path can be implemented very efficiently. The base planes make it possible to detect the visible face of Z-map model effectively. And the bounding box of tool sweep volume provides minimum area of screen to be updated. The proposed techniques are suitable for implementation in raster graphic device and need a few memories and a small amount of calculation. Proposed method is written in C and executable on MS-Windows95 and Window-NT.

• Transactions of Materials Processing
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• v.13 no.4
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• pp.334-341
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• 2004

In this study, a remeshing algorithm adapted to the mesh density map using the Delaunay mesh generation method is developed. In the finite element simulation of forging process, the numerical error increases as the process goes on because of discrete property of the finite elements and distortion of elements. Especially, in the region where stresses and strains are concentrated, the numerical error will be highly increased. However, it is not desirable to use a uniformly fine mesh in the whole domain. Therefore, it is necessary to reduce the analysis error by constructing locally refined mesh at the region where the error is concentrated such as at the die corner. In this paper, the point insertion algorithm is used and the mesh size is controlled by using a mesh density map constructed with a posteriori error estimation. An optimized smoothing technique is adopted to have smooth distribution of the mesh and improve the mesh element quality.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.3
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• pp.342-348
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• 2004

As the advent of the Internet, B2B negotiation process on the Internet has been given attention from both researchers and practitioners. However, literature still shows that only structured conditions have been explicitly considered, despite the fact that unstructured conditions should be rendered as well. In this sense, this paper proposes a new negotiation support mechanism to incorporate causal relationships between structured and unstructured conditions in the process of B2B negotiation. Fuzzy cognitive map was used as a main source of causal knowledge as well causal inference engine. A prototype named CAKES-NEGO was developed to perform experiments with an illustrative example. Results revealed the robustness of our proposed negotiation support mechanism.

• Journal of the Korea Society for Simulation
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• v.14 no.1
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• pp.1-8
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• 2005

In the semiconductor manufacturing, yield enhancement is an urgent issue. It is ideal to prevent all the failures. However, when a failure occurs, it is important to quickly specify the cause stage and take countermeasure. Reviewing wafer level and composite lot level yield patterns has always been an effective way of identifying yield inhibitors and driving process improvement. This process is very time consuming and as such generally occurs only when the overall yield of a device has dropped significantly enough to warrant investigation. The automatic method of failure pattern extraction from fail bit map provides reduced time to analysis and facilitates yield enhancement. The automatic method of failure pattern extraction from fail bit map provides reduced time to analysis and facilitates yield enhancement. This paper describes the techniques to automatically classifies a failure pattern using a fail bit map.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.113-115
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• 2010

We studied the methods to utilize vehicle-based mobile mapping system for field investigation work of digital map generation process. Map layers which should be checked by field investigation were analyzed to find the possibility of being checked with data from vehicle-based mobile mapping system. Also new process for digital map generation were suggested to adopt field investigation by vehicle-based mobile mapping system. We performed field investigation work on the Kangneung area by vehicle-based mobile mapping on a trial bases and compared the results with a results from usual field investigation method.