• Title/Summary/Keyword: Hierarchical algorithm

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A Study on the Analytical Model of Shear Wall Considering the Current Status of Structural Design (구조설계실무 현황을 고려한 전단벽 해석모형에 관한 고찰)

  • Jung, Sung-Jin
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.9
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    • pp.3-10
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    • 2018
  • While computer environments have been dramatically developed in recent years, as the building structures become larger, the structural analysis models are also becoming more complex. So there is still a need to model one shear wall with one finite element. From the viewpoint of the concept of FEA, if one shear wall is modeled by one finite element, the result of analysis is not likely accurate. Shear wall may be modelled with various finite elements. Among them, considering the displacement compatibility condition with the beam element connected to the shear wall, plane stress element with in-plane rotational stiffness is preferred. Therefore, in order to analyze one shear wall with one finite element accurately, it is necessary to evaluate finite elements developed for the shear wall analysis and to develop various plane stress elements with rotational stiffness continuously. According to the above mentioned need, in this study, the theory about a plane stress element using hierarchical interpolation equation is reviewed and stiffness matrix is derived. And then, a computer program using this theory is developed. Developed computer program is used for numerical experiments to evaluate the analysis results using commercial programs such as SAP2000, ETABS, PERFORM-3D and MIDAS. Finally, the deflection equation of a cantilever beam with narrow rectangular section and bent by an end load P is derived according to the elasticity theory, and it is used to for comparison with theoretical solution.

Improving Classification Accuracy in Hierarchical Trees via Greedy Node Expansion

  • Byungjin Lim;Jong Wook Kim
    • Journal of the Korea Society of Computer and Information
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    • v.29 no.6
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    • pp.113-120
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    • 2024
  • With the advancement of information and communication technology, we can easily generate various forms of data in our daily lives. To efficiently manage such a large amount of data, systematic classification into categories is essential. For effective search and navigation, data is organized into a tree-like hierarchical structure known as a category tree, which is commonly seen in news websites and Wikipedia. As a result, various techniques have been proposed to classify large volumes of documents into the terminal nodes of category trees. However, document classification methods using category trees face a problem: as the height of the tree increases, the number of terminal nodes multiplies exponentially, which increases the probability of misclassification and ultimately leads to a reduction in classification accuracy. Therefore, in this paper, we propose a new node expansion-based classification algorithm that satisfies the classification accuracy required by the application, while enabling detailed categorization. The proposed method uses a greedy approach to prioritize the expansion of nodes with high classification accuracy, thereby maximizing the overall classification accuracy of the category tree. Experimental results on real data show that the proposed technique provides improved performance over naive methods.

Efficient Motion Information Representation in Splitting Region of HEVC (HEVC의 분할 영역에서 효율적인 움직임 정보 표현)

  • Lee, Dong-Shik;Kim, Young-Mo
    • Journal of Korea Multimedia Society
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    • v.15 no.4
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    • pp.485-491
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    • 2012
  • This paper proposes 'Coding Unit Tree' based on quadtree efficiently with motion vector to represent splitting information of a Coding Unit (CU) in HEVC. The new international video coding, High Efficiency Video Coding (HEVC), adopts various techniques and new unit concept: CU, Prediction Unit (PU), and Transform Unit (TU). The basic coding unit, CU is larger than macroblock of H.264/AVC and it splits to process image-based quadtree with a hierarchical structure. However, in case that there are complex motions in CU, the more signaling bits with motion information need to be transmitted. This structure provides a flexibility and a base for a optimization, but there are overhead about splitting information. This paper analyzes those signals and proposes a new algorithm which removes those redundancy. The proposed algorithm utilizes a type code, a dominant value, and residue values at a node in quadtree to remove the addition bits. Type code represents a structure of an image tree and the two values represent a node value. The results show that the proposed algorithm gains 13.6% bit-rate reduction over the HM-1.0.

Depth-map Preprocessing Algorithm Using Two Step Boundary Detection for Boundary Noise Removal (경계 잡음 제거를 위한 2단계 경계 탐색 기반의 깊이지도 전처리 알고리즘)

  • Pak, Young-Gil;Kim, Jun-Ho;Lee, Si-Woong
    • The Journal of the Korea Contents Association
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    • v.14 no.12
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    • pp.555-564
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    • 2014
  • The boundary noise in image syntheses using DIBR consists of noisy pixels that are separated from foreground objects into background region. It is generated mainly by edge misalignment between the reference image and depth map or blurred edge in the reference image. Since hole areas are generally filled with neighboring pixels, boundary noise adjacent to the hole is the main cause of quality degradation in synthesized images. To solve this problem, a new boundary noise removal algorithm using a preprocessing of the depth map is proposed in this paper. The most common way to eliminate boundary noise caused by boundary misalignment is to modify depth map so that the boundary of the depth map can be matched to that of the reference image. Most conventional methods, however, show poor performances of boundary detection especially in blurred edge, because they are based on a simple boundary search algorithm which exploits signal gradient. In the proposed method, a two-step hierarchical approach for boundary detection is adopted which enables effective boundary detection between the transition and background regions. Experimental results show that the proposed method outperforms conventional ones subjectively and objectively.

Human Body Motion Tracking Using ICP and Particle Filter (반복 최근접점와 파티클 필터를 이용한 인간 신체 움직임 추적)

  • Kim, Dae-Hwan;Kim, Hyo-Jung;Kim, Dai-Jin
    • Journal of KIISE:Software and Applications
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    • v.36 no.12
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    • pp.977-985
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    • 2009
  • This paper proposes a real-time algorithm for tracking the fast moving human body. Although Iterative closest point (ICP) algorithm is suitable for real-time tracking due to its efficiency and low computational complexity, ICP often fails to converge when the human body moves fast because the closest point may be mistakenly selected and trapped in a local minimum. To overcome such limitation, we combine a particle filter based on a motion history information with the ICP. The proposed human body motion tracking algorithm reduces the search space for each limb by employing a hierarchical tree structure, and enables tracking of the fast moving human bodies by using the motion prediction based on the motion history. Experimental results show that the proposed human body motion tracking provides accurate tracking performance and fast convergence rate.

Petri nets modeling and dynamic scheduling for the back-end line in semiconductor manufacturing (반도체 후공정 라인의 페트리 네트 모델링과 동적 스케쥴링)

  • Jang, Seok-Ho;Hwang, U-Guk;Park, Seung-Gyu;Go, Taek-Beom;Gu, Yeong-Mo;U, Gwang-Bang
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.6
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    • pp.724-733
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    • 1999
  • An effective method of system modeling and dynamic scheduling for the back-end line of semiconductor manufacturing is proposed. The virtual factory, describing semiconductor manufacturing line, is designed in detail, and then a Petri net model simulator is developed for operation and control of the modular cells of the virtual factory. The petri net model is a colored timed Petri nets (CTPNs). The simulator will be utilized to analyze and evaluate various dynamic status and operatons of manufacturing environments. The dynamic schedulaer has a hierarchical structure with the higher for planning level and the lower for dynamic scheduling level. The genetic algorithm is applied to extract optimal conditions of the scheduling algorithm. The proposed dynamic scheduling is able to realize the semiconductor manufacturing environments for the diversity of products, the variety of orders by many customers, the flexibility of order change by changing market conditions, the complexity of manufacturing processes, and the uncertainty of manufacturing resources. The proposed method of dynamic scheduling is more effective and useful in dealing with such recent pressing requirements including on-time delivery, quick response, and flexibility.

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An Incremental Web Document Clustering Based on the Transitive Closure Tree (이행적 폐쇄트리를 기반으로 한 점증적 웹 문서 클러스터링)

  • Youn Sung-Dae;Ko Suc-Bum
    • Journal of Korea Multimedia Society
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    • v.9 no.1
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    • pp.1-10
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    • 2006
  • In document clustering methods, the k-means algorithm and the Hierarchical Alglomerative Clustering(HAC) are often used. The k-means algorithm has the advantage of a processing time and HAC has also the advantage of a precision of classification. But both methods have mutual drawbacks, a slow processing time and a low quality of classification for the k-means algorithm and the HAC, respectively. Also both methods have the serious problem which is to compute a document similarity whenever new document is inserted into a cluster. A main property of web resource is to accumulate an information by adding new documents frequently. Therefore, we propose a new method of transitive closure tree based on the HAC method which can improve a processing time for a document clustering, and also propose a superior incremental clustering method for an insertion of a new document and a deletion of a document contained in a cluster. The proposed method is compared with those existing algorithms on the basis of a pre챠sion, a recall, a F-Measure, and a processing time and we present the experimental results.

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Design and Performance Analysis of Caching Algorithms for Distributed Non-uniform Objects (분산 이질형 객체 환경에서 캐슁 알고리즘의 설계 및 성능 분석)

  • Bahn, Hyo-Kyung;Noh, Sam-Hyeok;Min, Sang-Lyul;Koh, Kern
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.6
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    • pp.583-591
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    • 2000
  • Caching mechanisms have been studied extensively to buffer the speed gap of hierarchical storages in the context of cache memory, paging system, and buffer management system. As the wide-area distributed environments such as the WWW extend broadly, caching of remote objects becomes more and more important. In the wide-area distributed environments, the cost and the benefit of caching an object is not uniform due to the location of the object; which should be considered in the cache replacement algorithms. For online operation, the time complexity of the replacement algorithm should not be excessive. To date, most replacement algorithms for the wide-area distributed environments do not meet both the non-uniformity of objects and the time complexity constraint. This paper proposes a replacement algorithm which considers the non-uniformity of objects properly; it also allows for an efficient implementation. Trace-driven simulations show that proposed algorithm outperforms existing replacement algorithms.

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Iso-density Surface Reconstruction using Hierarchical Shrink-Wrapping Algorithm (계층적 Shrink-Wrapping 알고리즘을 이용한 등밀도면의 재구성)

  • Choi, Young-Kyu;Park, Eun-Jin
    • Journal of KIISE:Computer Systems and Theory
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    • v.36 no.6
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    • pp.511-520
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    • 2009
  • In this paper, we present a new iso-density surface reconstruction scheme based on a hierarchy on the input volume data and the output mesh data. From the input volume data, we construct a hierarchy of volumes, called a volume pyramid, based on a 3D dilation filter. After constructing the volume pyramid, we extract a coarse base mesh from the coarsest resolution of the pyramid with the Cell-boundary representation scheme. We iteratively fit this mesh to the iso-points extracted from the volume data under O(3)-adjacency constraint. For the surface fitting, the shrinking process and the smoothing process are adopted as in the SWIS (Shrink-wrapped isosurface) algorithm[6], and we subdivide the mesh to be able to reconstruct fine detail of the isosurface. The advantage of our method is that it generates a mesh which can be utilized by several multiresolution algorithms such as compression and progressive transmission.

Automatic Photovoltaic Panel Area Extraction from UAV Thermal Infrared Images

  • Kim, Dusik;Youn, Junhee;Kim, Changyoon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.6
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    • pp.559-568
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    • 2016
  • For the economic management of photovoltaic power plants, it is necessary to regularly monitor the panels within the plants to detect malfunctions. Thermal infrared image cameras are generally used for monitoring, since malfunctioning panels emit higher temperatures compared to those that are functioning. Recently, technologies that observe photovoltaic arrays by mounting thermal infrared cameras on UAVs (Unmanned Aerial Vehicle) are being developed for the efficient monitoring of large-scale photovoltaic power plants. However, the technologies developed until now have had the shortcomings of having to analyze the images manually to detect malfunctioning panels, which is time-consuming. In this paper, we propose an automatic photovoltaic panel area extraction algorithm for thermal infrared images acquired via a UAV. In the thermal infrared images, panel boundaries are presented as obvious linear features, and the panels are regularly arranged. Therefore, we exaggerate the linear features with a vertical and horizontal filtering algorithm, and apply a modified hierarchical histogram clustering method to extract candidates of panel boundaries. Among the candidates, initial panel areas are extracted by exclusion editing with the results of the photovoltaic array area detection. In this step, thresholding and image morphological algorithms are applied. Finally, panel areas are refined with the geometry of the surrounding panels. The accuracy of the results is evaluated quantitatively by manually digitized data, and a mean completeness of 95.0%, a mean correctness of 96.9%, and mean quality of 92.1 percent are obtained with the proposed algorithm.