• 제목/요약/키워드: Subdivision scheme

검색결과 53건 처리시간 0.027초

Adaptive mesh refinement/recovery strategy for FEA

  • Choi, Chang-Koon;Lee, Eun-Jin;Yu, Won-Jin
    • Structural Engineering and Mechanics
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    • 제17권3_4호
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    • pp.379-391
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    • 2004
  • This paper deals with the development of h-version adaptive mesh refinement and recovery strategy using variable-node elements and its application to various engineering field problems with 2D quadrilateral and 3D hexahedral models. The variable-node elements which have variable mid-side nodes on edges or faces are effectively used in overcoming some problems in connecting the different layer patterns of the transition zone between the refined and coarse mesh. A modified recovery technique of gradients adequate for variable-node elements and proper selection of error norms for each engineering field problems are proposed. In the region in which the error is greater than the permissible refinement error, the mesh is locally refined by subdivision. Reversely, in some parts of the domain having the error smaller than the permissible recovery error, the mesh is locally recovered (coarsened) by combination. Hierarchical structures (e.g. quadtrees and octrees) and element-based storage structures are composed to perform this adaptive process of refinement and recovery. Some numerical examples of a 3D heat conduction analysis of the concrete with hydration heat and a 2D flow analysis of vortex shedding show effectiveness and validity of the proposed scheme.

국내 인터넷 서점의 건강 분야 분류체계 개선 방안에 관한 연구 (A Study on Improving a Classification for Health Categories of Internet Bookstores in Korea)

  • 최예진;정연경
    • 정보관리학회지
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    • 제30권3호
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    • pp.49-70
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    • 2013
  • 본 연구는 인터넷 서점의 건강분야 분류체계의 개선방안으로 이를 위해 국내 외 8곳의 인터넷 서점의 건강분야 분류체계 현황을 비교분석하고, KDC, DDC의 해당 주제 분류항목과 비교 분석하였다. 그리고 인터넷 서점의 건강분야 분류체계의 이용에 대한 이용자 면담을 진행하였다. 그 결과를 바탕으로 설계원칙을 수립하고, 인터넷 서점의 건강분야 분류체계 설계안을 개발한 후, 실무자와 전문가 평가를 받아서 건강이란 대분류 아래 11개의 중분류 항목과 60개의 소분류 항목, 16개의 세분류 항목으로 제시하였다. 본 연구의 결과는 인터넷 서점은 물론 웹상에서 건강 관련 정보를 효율적으로 분류하는 기반이 될 것이다.

효율적인 데이터 저장을 기초로 한 광선 추적의 가속화 방안 (Ray Tracing Acceleration Schemes Based on Efficient Data Storage)

  • 최현규;경종민
    • 대한전자공학회논문지
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    • 제26권8호
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    • pp.1270-1281
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    • 1989
  • This paper presents two new storage schemes of 3-D objects to accelerate the finding of the first intersecting object and the shadow computation steps in ray tracing. The 3-D objects which are potentially intersected with the first reflection (refraction)ray are enrolled within a so called reflection (refraction) frustum' for a polygon object. Only those objects registered in the corres ponding frustum are immediately checked for intersection with the secondary rays emanating from the same polygon. The other is called a shadow pyramid' which contains the candidate objects possibly blocking the path from the relevant light source to any point on the relevant polgon. The shadow testing of a point is performed only against the objects contained in the associated shadow pyramid. Despite the cost needed for registration of objects within frusta or shadow pyramids, the total rendering time of ray tracing using the proposed approaches was reduced by approximately 50% (10% in color rendering time and 70% in shadoe testing time) from the conventional cell 50% (10% in color rendering time and 70% in shadow testing time) from the conventional cell traversal scheme under the 3-D uniform subdivision environment due to the fast finding of candidate objects for intersection and the reduced number of intersection calculations.

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ANALYSIS OF THE NODALISATION INFLUENCE ON SIMULATING ATMOSPHERIC STRATIFICATIONS IN THE EXPERIMENT THAI TH13 WITH THE CONTAINMENT CODE SYSTEM COCOSYS

  • Burkhardt, Joerg;Schwarz, Siegfried;Koch, Marco K.
    • Nuclear Engineering and Technology
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    • 제41권9호
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    • pp.1135-1142
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    • 2009
  • The activities related to this paper are to investigate the influence of nodalisation on simulating atmospheric stratification in the THAI experiment TH13 (ISP-47) with the German containment code COCOSYS. This article focuses on different nodalisations of the vessel dome, where an atmospheric stratification occurred due to a high helium content. The volume of the dome was divided into several levels that were varied horizontally into different geometries. These geometries differ in the number of zones as well as in the existence of zones that enable the direct rise of an ascending steam plume into the vessel dome. Additionally, the vertical subdivision of the vessel dome was increased to simulate density gradients in a more detailed way. It was pointed out that the proper simulation of atmospheric stratifications and their dissolution depends on both a suitable horizontal as well as vertical nodalisation scheme. Besides, the treatment of fog droplets has an influence if their settlement is not simulated correctly. This report gives an overview of the gained experience and provides nodalisation requirements to simulate atmospheric stratifications and their proper dissolution.

한국십진분류법 기록관리학 분야 분류체계 개선에 관한 연구 (A Study on the Improvement of the Classification System on Archives and Records Management Studies in KDC)

  • 박수현;이명규
    • 한국비블리아학회지
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    • 제27권3호
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    • pp.25-50
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    • 2016
  • 기록관리학이 독자적인 학문영역으로 발전해가고 있다. 하지만 KDC를 비롯한 기존의 문헌분류표에서는 분류 항목 배열이 기록관리학의 특성을 제대로 반영하지 못하여 분류항목의 전개가 불합리한 부분이 있으며, 주제영역별 세목전개의 재배치가 필요하다. 따라서 이 연구에서는 기록관리학의 학문 특성에 따라 주제영역을 기록관리 일반, 기록관리 법 정책, 기록물의 수집 선별 평가, 기록물의 조직, 기록정보서비스, 기록물 관리 및 보존, 기록관 운영, 기록관리 기관 등 8개 영역으로 설정하고, 현대 주요 문헌분류표인 KDC, DDC, NDC, UDC, LCC의 분류체계를 분석한 후, "대한민국 국가서지"의 기록관리학 분야 유별 자료현황 및 주제어 분석 결과를 반영하여 KDC 기록관리학 분야의 분류체계 수정 전개 방안을 제시하였다. 기록관리학 관련 주제영역 8개 분야의 내용은 KDC 028로 통합할 수 있도록 변경하였다.

OFDM 기법에 기반한 Multi-Cell 시스템에서 PAPR 감소와 대역간 간섭에 관한 연구 (A Study on Inter Band Interference and PAPR Reduction in Multi-Cell System based on OFDM Techniques)

  • 김완태;유선용;조성준
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2008년도 추계종합학술대회 B
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    • pp.693-696
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    • 2008
  • 4세대 이동 통신 서비스를 위한 시스템들은 멀티미디어 서비스를 지원하기 위해 대용량 데이터 전송이 가능한 OFDM(Orthogonal frequency Division Multiplexing) 방식을 이용하고, 서비스의 질을 높이기 위해 통신 영역을 세분화하여 Macro Cell, Pico Cell, Femto Cell 등으로 구성하고 있다. 통신 영역의 세분화로 인해 기존에 단일 Cell 을 사용하는 것과 달리 동일한 채널에서 Cell을 중첩시켜 서비스해야 하므로 시스템들 간의 대역간 간섭이 문제가 된다. 특히, OFDM 신호는 독립적으로 변조된 많은 부반송파들로 구성되므로 이들이 동위상으로 더해질 때 신호의 진폭이 증가하여 PAPR (Peak-to-Average Power Ratio) 문제가 발생한다. 높아진 PAPR은 전력 증폭기와 같은 비선형 소자를 통과하면서 신호의 왜곡이 발생하여 대역 외 스펙트럼 방출이 발생하므로 대역간 간섭으로 작용한다. 본 논문에서는 대역간 간섭을 최소화하기 위해 PAPR 감소기법을 적용한 후 전력증폭기와 같은 비선형 소자를 통과하면서 발생하는 대역 외 스펙트럼 방출에 대하여 분석하였다.

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

  • 최영규;박은진
    • 한국정보과학회논문지:시스템및이론
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    • 제36권6호
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    • pp.511-520
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    • 2009
  • 본 논문에서는 입력 볼륨 데이터와 출력 메쉬 데이터에서 모두 계층성을 지원하는 새로운 등밀도 표면의 재구성 방법을 제안한다. 제안된 방법은 먼저 입력 볼륨 데이터로부터 3차원 팽창 필터를 사용하여 볼륨 피라미드라 불리는 볼륨의 계층구조를 만든다. 볼륨 피라미드가 만들어진 후 해상도가 최저인 피라미드의 최상단 볼륨에서부터 셀경계표현 방법을 이용하여 조악한 초기 메쉬를 생성한다. 이러한 메쉬를 반복적으로 변형하여 O(3)-인접성 조건하에서 추출한 등밀도점을 잘 근사하도록 하는데, 이를 위해 SWIS (표면축소기반의 등밀도면 재구성법[6]) 알고리즘에서 사용되었던 표면 축소 단계와 평활화 단계를 사용한다. 또한 최종등밀도면의 정밀한 표면을 만들 수 있도록 메쉬를 반복적으로 분할(subdivision)한다. 제안된 방법은 생성되는 표면이 표면의 압축이나 점진적인 전송 등과 같은 다중 해상도 알고리즘에 활용될 수 있다는 장점이 있다.

기계화를 전제로한 산간경사지답 경지정리 방안에 관한 연구 (A Study on the Methodology of Land-Consolidation Sloping Paddies in land valley for the Farm-Mechanization)

  • 성찬용;황근;한욱동
    • 한국농공학회지
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    • 제23권2호
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    • pp.61-69
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    • 1981
  • The paddies in the hillsides in Gonggeun-myeon, Hoingseong-gun, Kangweon-do keep a steep slope and run in and out. A land consolidation in such an area, therefore, will require high ratio of land loss and a large amount of earth moving if it follows the existing design criteria to separate drainage and irrigation ditches in a scheme. Due to the consequent decrease in construction cost, the project has not been envisaged. in order to secure the introduction of small-medium size farm machineries into the paddies, farm plots were planned to be straight and drainage with taking care of topography. Findings from the comparison of methodologies are as follows. 1. In places with a solpe of more than 1/30, a reduction in earth moving can be expected with parallel plots to the contours. 2, For the sake of effective using of farm machineries, it is thought that a plot should be running straight parallel to the contours and the ratio of length and width of a plot be more than six. 3. In places with a slop of more than 1/10, a reduction in earth moving and a effective introduction of farm-machineries can he expected with straight parllel plots to the contours. But it is undesirable to introduce a scheme in this places because of the difficulties in acreage computation and farmers' hesitation. 4. The system with a canal for both irrigation and drainage is highly effective to decrease the ratio of land loss as well as construction cost. 5. Parallel plots to the contours and a canal for both irrigation and drainage are highly effective in the decrease in construct cost. 6. To avoid the subdivision of a cooperation in farming is desirable of a plots, has more than two owners.

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임대차 분쟁의 조정과 중재에 관한 연구 (A Study on the Mediation and Arbitration of Lease Dispute)

  • 남선모
    • 한국중재학회지:중재연구
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    • 제25권4호
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    • pp.119-136
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    • 2015
  • The contracting parties must be provided a litigation scheme in order to resolve a dispute. This means taking advantage of effective measures for mediation or arbitration. A lease transaction is likely to occur mainly after a dispute. It is necessary to take the appropriate measures in advance. In general, when a variety of contracts are created, conflicts arise and disputes have to be resolved through mediation and arbitration documents, and adjustment or intervention is called for. Arbitration system is a system that is established based on the trust of the arbitral tribunal. For such system, quality education for enhancing professionalism required of the arbitrator is important. A party responding to an arbitration agreement presents a problem. The current system must ensure that there are no disadvantaged parties. However, a party must depend on an arbitration agreement that is part of the law rescue system. A litigation support by the local Bar Association must be carried out. It should be notified of the contents of the contract to select a strategy that will best resolve the conflict. In the case of lease transactions, there is a need to create a scheme to make a standard agreement that inserts an arbitration clause. Lease sale and purchase agreement or lease agreement is a form of contract that has been frequently used. Here, the arbitration agreement clause for a lawyer that will serve as arbitrator should be inserted. It is a scheme that can be activated for individuals in poor areas. In addition, it is possible to see it taking a scheme to take advantage of the lawyer system for the future of the town. The Attorney System of a town is a system that the Korean Bar Association, Legal Department has put in place since 2013. If a real estate trade dispute occurs, the role of the intermediary attorney should be to carry out his duties efficiently. In the case of real estate transaction conflicts, the lawyer of the village should be registered as the arbitrator. It is important to establish a basis of regulations through this type of real estate transaction accident analysis. Before proceeding with various adjustment systems, it is desirable to expand the arbitration region. Now we need a realtor amendment. It is the part where fragmentation of intermediary qualification is required, along with the eligibility of a subdivision.

태음인(太陰人) 병증(病證) 분류(分類)에 관한 연구(硏究) (A study on the schematic organization of the sub-classification system of the Taeeumin symptomatology)

  • 이준희;이의주;고병희
    • 사상체질의학회지
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    • 제23권1호
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    • pp.63-78
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    • 2011
  • 1. Objectives: We aimed to propose a sub-classification system for the Taeeumin symptomatology by examining the Taeeumin pathology and symptomatology descriptions appearing in "Donguisusebowon". 2. Methods: The Gabo Edition and the Sinchuk Edition (the upgraded and revised edition) of "Donguisusebowon" were reviewed and examined for relevant information on the Taeeum pathology and symptomatology. 3. Results and Conclusions: 1) In the Taeeumin symptomatology, the Exterior disease develops from the basic pathology of Esophagus-Cold and the Interior disease from that of Liver-Heat, eventually progressing to damage of the expirational and dispersive energy of the Lung Sector, the Prime Core Organ or the excessively small organ of the Taeeum constitutional type. The resulting pathology can be broadly defined as the "Lung-Dryness symptomatology". 2) The case reports introduced in the Exterior disease section, including the Zhang Zhongjing Mahuang-tang treatment, Prolonged-affliction disease treatment, and Exterior disease Pestilential disease treatment, share several points in common. They all arise from the pathology of "weakness in the Lung sector and deficiency in the Exterior sector", and they can all be assigned to the same symptomatological division that presents with systemic heat and cold intolerance; this symptomatology can be defined as the "Esophagus-Cold symptomatology", the milder subdivision of the exterior symptomatology. 3) The body of text appearing in the last part of the Interior disease section commonly referred to as the "Taeeumin Conspectus" is in fact not a conspectus when its contents are actually examined. Instead, it can be understood from its pathological and symptomatological descriptions that the passage is explaining the more severe subdivision of the exterior symptomatology that has progressed from Esophagus-Cold to a pathology characterized by damaged expirational and dipersive energy of the Lung Sector. 4) The relocation of the "dry-related pathology" indicates a change in perspective regarding the "Dry-related symptomatology", which caused the rearrangement of the Interior disease into divisions of Liver-Heat symptomatology that is characterized by fulminant heat pathology and Dry-Heat symptomatology that is also accompanied by Lung-Dryness. 5) The Interior disease Yin-Blood Consumptive symptomatology should be included in the Dry-Heat symptomatology in the pathological scheme. 6) Based on the above, the subdivisions of the Taeeumin symptomatology should be arranged as "Esophagus-Cold symptomatology" and "Lung-Dry-Cold symptomatology" in the Exterior disease and "Liver-Heat symptomatology" and "Dry-Heat symptomatology" in the Interior disease.