• International Journal of Fuzzy Logic and Intelligent Systems
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• 제9권1호
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• pp.36-41
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• 2009

Self organizing map(SOM) is one of the unsupervised methods based on the competitive learning. Many clustering works have been performed using SOM. It has offered the data visualization according to its result. The visualized result has been used for decision process of descriptive data mining as exploratory data analysis. In this paper we propose improvement of SOM using stratified sampling of statistics. The stratification leads to improve the performance of SOM. To verify improvement of our study, we make comparative experiments using the data sets form UCI machine learning repository and simulation data.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2015년도 춘계학술발표대회
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• pp.546-548
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• 2015

최근에는 자동차 전장용 소프트웨어 결함으로 인한 피해로 자동차 리콜 사태가 일어나는 것을 종종 볼 수 있다. 소프트웨어 검사와 TMMi 프로세스를 전장용 소프트웨어에 이용한다면 소프트웨어 결함을 줄이며 사고 발생률 역시 감소될 수 있다. 전장용 소프트웨어에 이를 적용해 볼 때, 검사 방법에 적합한 방향으로 검사 프로세스를 개선할 수 있으며, 고품질 소프트웨어 또한 구현할 수 있다.

• 정보관리연구
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• 제34권2호
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• pp.67-88
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• 2003

정보량이 급증하고 기존의 정보조직체계에 비해 덜 체계화된 정보를 제공하는 인터넷의 확산 등으로 인해 정보시각화에 대한 관심이 점점 증가하고 있다. 정보 시각화는 이용자가 원하는 정보에 쉽고 적은 노력으로 접근할 수 있도록 데이터를 재정리하고 요약하여 보여주는 기법이다. 현재까지 개발되어 온 많은 정보시각화 기법들은 과학적인 연산절차에 근거하여 데이터를 표현하는 방법을 사용하여 왔는데, 이러한 과학적 데이터 처리 과정에 의존하는 시각화방법은 일반 이용자들이 이해하기에는 어려움과 사용의 불편함이 따른다. 더 중요하고 심각한점은, 이러한 정보시각화 기법을 사용하는 많은 시스템의 모형들이 실제 이용자가 경험하는 상황을 반영하는 경우가 매우 드물다는 현실이다. 예를 들어, 이용자는 데이터를 처리하거나 정보를 제시함에 있어 어안적 방법(fisheye view)을 사용하거나 주제정경 (the mescape)을 사용하지 않는다. 이는 현재의 많은 정보 시각화 시스템들이 이용자 관점에서 시스템을 설계하는 행동유도성（affordance)을 반영하지 않고 있음을 지적한다. 이 연구는 이용자의 요구사항이 반영되지 않고, 이용자에게 부담을 지우는 시각화 시스템의 문제점을 분석하였다. 이를 위하여, 네 가지의 대표적인 정보시각화 시스템을 분석, 평가하였는데 이 때 평가의 기준으로 Norman의 이용자 인터페이스 설계 원칙 및 Nielson의 휴리스틱 평가 방법을 이용하였다. 문제점 분석 결과를 통하여, 이용자의 요구를 반영하지 못한 시스템 설계의 측면들을 확인할 수 있었다. 특히, 이용자와 시스템간의 부합정도 및 시스템의 상태를 이용자가 알 수 있도록 보여주는 가시성 등은 네 가지 시스템의 평가에서 모두 문제점으로 지적되었다. 이 연구의 결과는 정보시각화 및 표현에 있어서 이용자의 요구를 이해하고 이용성을 고려한 설계의 필요성을 강조하고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권6호
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• pp.667-681
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• 2009

We describe a method to decompose a cube with trilinear interpolation into a collection of tetrahedra with linear interpolation, where the isosurface topology is preserved for all isovalues during decomposition. Visualization algorithms that require input scalar data to be defined on a tetrahedral grid can utilize our method to process 3D rectilinear data with topological correctness. As one of many possible examples, we apply the decomposition method to topologically accurate tetrahedral mesh extraction of an interval volume from trilinear volumetric imaging data. The topological correctness of the resulting mesh can be critical for accurate simulation and visualization.

• 한국가시화정보학회지
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• 제9권4호
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• pp.69-73
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• 2011

Butterflies have been known to suck viscous liquids through a long, cylindrical proboscis using the large pressure difference formulated by the cyclic expansion and contraction of a muscular pump located inside their head. However, there are few studies on the liquid-feeding phenomena in a live butterfly, because it is hard to observe the internal morphological structures under in vivo condition. In this study, the dynamic motion of the pump system in a butterfly was in vivo visualized using synchrotron X-ray micro-imaging technique to analyze the liquid-feeding mechanism. The period of the liquid-feeding process is about 0.3sec. The expansion stage is about two times larger than the contraction stage in one cycle. The cyclic variation of pump volume generate large negative suction pressure and the pressure difference inside the long proboscis of a butterfly is estimated to be larger than 1atm.

• 한국가시화정보학회지
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• 제9권4호
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• pp.22-27
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• 2011

In this study, we present methods of coupling a commercial code, ANSYS CFX, and the user Fortran codes for solving an unsteady electro-osmotic flow around a pair of electrodes, receiving DC, attached to the top and the bottom walls of a two-dimensional cavity. We developed a module of Fortran programs for solving the ion-transport equations as well as the Poisson equations for the potential to be used in coupling with the CFX. We present how the developed codes are applied to solving the transient DC electro-osmotic flow problem within a simple cavity. We also address various problems encountered during the development process and explain why such problems are raised.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1104-1108
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• 2007

Automobile sunroof buffeting is the tonal noise of low frequency around 20Hz. It occurs due to the acoustic feedback process between the shear layer detached from the leading edge of sunroof opening and the Helmholtz resonator-like property of a car cabin. In this paper, PIV visualization technique is applied to the unsteady flow field around sunroof opening of an SUV in the full-scale automotive wind tunnel in order to find out buffeting mechanism. A phase-marking PIV measurement method, in which image and sound pressure are recorded simultaneously, and a phase-rearrangement post-processing program were developed for capturing noise-related velocity fields without expensive synchronization systems. Through this study, some characteristics of the real-car sunroof shear layers under various deflector conditions were identified and these results can provide insights into the noise reduction mechanism of the tube-type deflector.

• 한국멀티미디어학회논문지
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• 제19권5호
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• pp.970-978
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• 2016

This study suggests the visual contents of environment education using the Rainwater, Visual contents is more effective than writings in terms of delivering information. Environment education needs to be performed from the stage of early childhood as environment can be dealt throughout the overall daily life of learners. This study is to utilize animation contents for environment education to shift recognition of user on environment and deliver the information. For this purpose, virtual space, a theme park with motif of rain city operated by Rainwater was established. Then the process of utilizing Rainwater was shown using rides. Imaginary animal, a dragon and endangered animals were visualized as characters. So this paper is to suggest the possibility of visualization of environment education contents and stimulate 'interest' and provide educational information' on utilizing the Rainwater.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.381-384
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• 2000

Relationships between biochemical phenomena and hemodynamics on human endothelial cells are very important to study the mechanism of atherosclerotic formation and development. The objective of this study is to investigate the flow phenomena around the endothelial cell model by the PIV experiment. The microscopic images of endothelial cells were acquired by a CCD camera to fabricate the shape of endothelial cell. The cell models were fabricated by using a photoforming process. Two consecutive particle images were captured by the CCD camera for the image processing. Conifer powder as the tracing particles was added to water to visualize the flow field. The cross-correlation method was applied fer the image processing of the flow visualization. Pressure and wall shear stress variations on the surfaces of the endothelial cells were calculated to investigate the effects of hemodynamic forces on the morphological changes.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.121-122
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• 2002

The main principle of radiation therapy is to deliver optimum dose to tumor to increase tumor cure probability while minimizing dose to critical normal structure to reduce complications. RTP system is required for proper dose plan in radiation therapy treatment. The main goal of this research is to develop dose model for photon, electron, and brachytherapy, and to display dose distribution on patient images with optimum process. The main items developed in this research includes: (l) user requirements and quality control; analysis of user requirement in RTP, networking between RTP and relevant equipment, quality control using phantom for clinical application (2) dose model in RTP; photon, electron, brachytherapy, modifying dose model (3) image processing and 3D visualization; 2D image processing, auto contouring, image reconstruction, 3D visualization (4) object modeling and graphic user interface; development of total software structure, step-by-step planning procedure, window design and user-interface. Our final product show strong capability for routine and advance RTP planning.