• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.745-746
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• 2006

In this paper, we propose a new predictive coding scheme for color data of three-dimensional (3-D) mesh models. We exploit connectivity and geometry information to improve coding efficiency. After ordering all vertices in a 3-D mesh model with a vertex traversal technique, we employ a geometry predictor to compress the color data. The predicted color can be acquired by a weighted sum of reconstructed colors for adjacent vertices using both angles and distances between the current vertex and adjacent vertices.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.154-156
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• 2001

공간정보 및 속성정보를 저장 및 관리하여 서비스하는 지리정보시스템은 최근 네트워크 및 분산환경의 기술개발과 더불어 급격히 변화하고 있다. 이러한 지리 정보시스템은 기존의 패키지, 지역적 클라이언트/서버환경의 기술에서 컴포넌트 기반 기술로 자리메김하고 있는 실정이다. 이러한 컴포넌트 GIS의 기술발전을 위해서 OGC(OpenGIS Consortium)에서는 다양한 설계 및 구현 사양과 토픽을 제시하고 있으며, 대부분의 GIS 기술개발시장에서는 이러한 사양과 토픽에 맞게끔 시스템을 설계 및 구현하고 있다. 지리정보시스템에서 다루는 공간데이터는 크게 기하정보(Geometry)와 위상정보(Topology)로 나뉜다. 지리정보시스템에서 기본석인 질의나 분석에 있어서 기하정보 뿐만 아니라 위상정보도 시스템 전체의 성능에 큰 영향을 미치며, 이러한 위상 정보의 저장, 관리는 필수적이다. 본 논문에서는 개방형 컴포넌트 GIS에서의 기본 기하 데이터 모델인 OGC Simple Feature Geometry 모델과 위상정보 (Topolygy Information)를 나타내는 위상 데이터 모델의 통합 및 연동방법에 대해서 살펴보고, 이러한 데이터모델을 포함하고 있는, OGC 구현사항에 맞게 설계 및 구현된 전체시스템 아키텍쳐를 살펴 볼 것이다.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.663-666
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• 2005

The geometry stage, which performs the transformation and lighting operations of vertices, became the critical part in 3D graphics pipeline. In this paper, we have planned and designed the Geometry Processor for the better and more efficient way to process the real-time 3D using the floating point unit. We also designed a verification system for Geometry engine. It is implemented with Xilinx-Virtex2 and Visual C++.NET. In the Synopsis, we confirmed 100 MHz performance and 137107 cell area of Geometry Engine.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.9
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• pp.2355-2361
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• 1996

Convergence analysis on Godard's quartic(GQ) algorithm used for blind equalization is accomplished in this paper. First, we explain the local behavior of the GQ algoithm around the global minimum point of the average performance function. Then we consider the geometry of the average performance function. The main result is that a good initial parameter vector of the GQ algorithm can be chosen based on the information of the geometry of the average performance function.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2450-2469
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• 2018

In this paper, we develop a spatiotemporal model to analysis of cellular user in underlay D2D communication by using stochastic geometry and queuing theory. Firstly, by exploring stochastic geometry to model the user locations, we derive the probability that the SINR of cellular user in a predefined interval, which constrains the corresponding transmission rate of cellular user. Secondly, in contrast to the previous studies with full traffic models, we employ queueing theory to evaluate the performance parameters of dynamic traffic model and formulate the cellular user transmission mechanism as a M/G/1 queuing model. In the derivation, Embedded Markov chain is introduced to depict the stationary distribution of cellular user queue status. Thirdly, the expressions of performance metrics in terms of mean queue length, mean throughput, mean delay and mean dropping probability are obtained, respectively. Simulation results show the validity and rationality of the theoretical analysis under different channel conditions.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.49-52
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• 2002

This paper presents a fast algorithm for face detection from color images on internet. We use Mahalanobis distance between standard skin color and actual pixel color on IQ color space to segment skin color regions. The skin color regions are the candidate face region. Further, the locations of eyes and mouth regions are found by computing average pixel values on horizontal and vertical pixel lines. The geometry of mouth and eye locations is compared to the standard face geometry to eliminate false face regions. Our Method is simple and fast so that it can be applied to face search engine for internet.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.4
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• pp.1721-1737
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• 2020

Human apparent age estimation has become a popular research topic and attracted great attention in recent years due to its wide applications, such as personal security and law enforcement. To achieve the goal of age estimation, a large number of methods have been pro-posed, where the models derived through the cumulative attribute coding achieve promised performance by preserving the neighbor-similarity of ages. However, these methods afore-mentioned ignore the geometric structure of extracted facial features. Indeed, the geometric structure of data greatly affects the accuracy of prediction. To this end, we propose an age estimation algorithm through joint feature selection and manifold learning paradigms, so-called Feature-selected and Geometry-preserved Least Square Regression (FGLSR). Based on this, our proposed method, compared with the others, not only preserves the geometry structures within facial representations, but also selects the discriminative features. Moreover, a deep learning extension based FGLSR is proposed later, namely Feature selected and Geometry preserved Neural Network (FGNN). Finally, related experiments are conducted on Morph2 and FG-Net datasets for FGLSR and on Morph2 datasets for FGNN. Experimental results testify our method achieve the best performances.

• Korean Journal of Computational Design and Engineering
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• v.19 no.2
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• pp.182-190
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• 2014

Parametric modeling is one of BIM's characteristics and BIM have being utilized for constructability analysis, energy efficiency analysis, and so on in diverse construction field. However, parametric information's interoperation is not solved until now because different BIM tools have specific algorithm and methods to generate geometric information. To solve the problem, previous research suggested IFC-XML methodology. In this paper, authors studied connections between IFC-XML structure and script-based modeling commends to make libraries in commercial BIM tools such as ArchiCAD$^{TM}$ and Digital Project$^{TM}$. In addition, they made commends mapping tables to exchange geometry information of architectural components. Moreover, mapping system was developed to certify the mapping tables which is classified modeling commends. Finally, translated architectural component model was confirmed using exchanged geometry information in browser.

• Journal of the Korean Geographical Society
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• v.39 no.5 s.104
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• pp.804-818
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• 2004

As spatial data resources become more abundant, the potential for conflict among them increases. Those conflicts can exist between two or many spatial datasets covering the same area and categories. Therefore, it becomes increasingly important to be able to effectively relate these spatial data sources with others then create new spatial datasets with matching geometry and topology. One extensive spatial dataset is US Census Bureau's TIGER file, which includes census tracts, block groups, and blocks. At present, however, census maps often carry information that conflicts with municipally-maintained detailed spatial information. Therefore, in order to fully utilize census maps and their valuable demographic and economic information, the locational information of the census maps must be reconciled with the more accurate municipally-maintained reference maps and imagery. This paper formulates a conceptual framework and two map models of map conflation to make geometrically and topologically consistent source maps according to the reference maps. The first model is based on the cell model of map in which a map is a cell complex consisting of 0-cells, 1-cells, and 2-cells. The second map model is based on a different set of primitive objects that remain homeomorphic even after map generalization. A new hierarchical based map conflation is also presented to be incorporated with physical, logical, and mathematical boundary and to reduce the complexity and computational load. Map conflation principles with iteration are formulated and census maps are used as a conflation example. They consist of attribute embedding, find meaning node, cartographic 0-cell match, cartographic 1-cell match, and map transformation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.1-8
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• 2017

The purpose of this study is to propose a cache structure for processing large-volume building information modeling (BIM) geometry data,whereit is difficult to allocate physical memory. As the number of BIM orders has increased in the public sector, it is becoming more common to visualize and calculate large-volume BIM geometry data. Design and review collaboration can require a lot of time to download large-volume BIM data through the network. If the BIM data exceeds the physical free-memory limit, visualization and geometry computation cannot be possible. In order to utilize large amounts of BIM data on insufficient physical memory or a low-bandwidth network, it is advantageous to cache only the data necessary for BIM geometry rendering and calculation time. Thisstudy proposes acache structure for efficiently rendering and calculating large-volume BIM geometry data where it is difficult to allocate enough physical memory.