• 제목/요약/키워드: Complex Integral

검색결과 296건 처리시간 0.022초

회전근 개 파열의 이학적 검사 (Physical Examinations of Rotator Cuff Tear)

  • 김경천;이광진;신현대;변기용
    • Clinics in Shoulder and Elbow
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    • 제11권1호
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    • pp.13-18
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    • 2008
  • 견관절의 모든 병적 상황의 성공적인 치료에는 정확한 진단이 요구된다. 이학적 검사는 견관절 질환의 검사에 필수적인 요소이다. 통증, 근력의 저하, 운동범위의 감소, 그리고 불안정성은 다양한 견관절 병태생리에 의해 발생하는 가장 흔한 증상들이다. 따라서, 견관절 질환을 가진 환자에게 정교한 임상적 접근이 필수적이다. 다양한 진단적 검사와 임상적 측정을 포함한 표준화된 평가가 견관절 복합체에서 한 구성요소를 특정하게 검사함으로써 진단적 정확도를 향상시킨다. 대부분의 경우, 신중한 이학적 검사가 진단과 확진 및 추가적 조사를 위해 선택적으로 시도될 수 있는 영상학적 시술과 같은 특정 진단 기술을 계획하거나 제공하게 된다.

SURF 기반 특징점 추출 및 서술자 생성의 FPGA 구현 (FPGA Implementation of SURF-based Feature extraction and Descriptor generation)

  • 나은수;정용진
    • 한국멀티미디어학회논문지
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    • 제16권4호
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    • pp.483-492
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    • 2013
  • SURF는 영상의 특징점을 추출하고 서술자를 생성하는 알고리즘으로 객체인식 및 추적, 파노라마 이미지 생성 등 여러 영상처리 시스템에 응용되고 있다. SURF 알고리즘은 영상의 크기, 회전, 시점 등의 변화에 강인한 특징을 갖지만 복잡하고 반복적인 연산이 많아 실시간 처리가 어렵다. 실제 PC(Pentium, 3.3GHz) 환경에서 1000개 정도의 특징점이 추출되는 VGA($640{\times}480$) 해상도의 영상을 이용하여 실험한 결과 특징점 추출 및 서술자 생성에 총 240ms 이상이 걸려 약 4frame/sec로 실시간 처리가 불가능한 것을 확인하였다. 본 논문에서는 SURF 알고리즘의 메모리 접근 패턴을 분석하여 라인 메모리를 효율적으로 구성해 메모리 사용을 최소화하고 반복적으로 수행되는 연산을 병렬처리 하는 방법으로 하드웨어를 설계하였다. 하드웨어 설계 검증 결과 Xilinx사의 Virtex5LX330 FPGA를 타겟으로 합성 시 101,348LUTs(66%)와 1,367KB의 내부 메모리를 사용하고, 100MHz 동작 클록에서 30 frame/sec로 실시간 처리가 가능함을 볼 수 있었다.

풍력 발전기 피치 제어를 위한 퍼지 PI 제어기 (A Fuzzy PI Controller for Pitch Control of Wind Turbine)

  • 천종민;김진욱;김홍주;최영규;김무림
    • 드라이브 ㆍ 컨트롤
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    • 제15권1호
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    • pp.28-37
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    • 2018
  • When the wind speed rises above the rated wind speed, the produced power of the wind turbines exceeds the rated power. Even more, the excessive power results in the undesirable mechanical load and fatigue. A solution to this problem is pitch control of the wind turbines. This paper presents a systematic design method of a collective pitch controller for the wind turbines using a discrete fuzzy Proportional-Integral (PI) controller. Unlike conventional PI controllers, the fuzzy PI controller has variable gains according to its input variables. Generally, tuning the parameters of fuzzy PI controller is complex due to the presence of too many parameters strongly coupled. In this paper, a systematic method for the fuzzy PI controller is presented. First, we show the fact that the fuzzy PI controller is a superset of the PI controller in the discrete-time domain and the initial parameters of the fuzzy PI controller is selected by using this relationship. Second, for simplicity of the design, we use only four rules to construct nonlinear fuzzy control surface. The tuning parameters of the proposed fuzzy PI controller are also obtained by the aforementioned relationship between the PI controller and the fuzzy PI controller. As a result, unlike the PI controller, the proposed fuzzy PI controller has variable gains which allow the pitch control system to operate in broader operating regions. The effectiveness of the proposed controller is verified with computer simulations using FAST, a NREL's primary computer-aided engineering tool for horizontal axis wind turbines.

유한요소/경계요소 연성해석을 통한 수중 구조기인소음 해석 (Underwater Structure-Borne Noise Analysis Using Finite Element/Boundary Element Coupled Approach)

  • 이두호;김현실;김봉기;이성현
    • 대한기계학회논문집A
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    • 제36권7호
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    • pp.789-796
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    • 2012
  • 함정의 수중방사소음은 그 해석의 어려움이나 정확성에 있어서 매우 관심이 큰 문제이다. 본 논문에서는 구조물의 수중방사소음을 해석하기 위하여 유한요소/경계요소 연성해석법을 제안하였다. 제안된 방법은 헤름홀츠방정식에 대한 Burton-Miller 적분방정식에 기반하는 부가수 질량과 감쇠행렬을 이용하여 구조물의 구조-유체 연성응답을 해석하고 계산된 구조물의 응답으로부터 수중방사소음을 계산하는 순차적인 방법이다. 구조-유체연성작용의 구조해석은 상용소프트웨어인 MSC/NASTRAN 에 구조-유체연성효과 행렬을 추가하여 해석하는 방법으로 이루어졌고, 수중방사소음의 경우는 전용 소프트웨어를 개발하였다. 개발된 수중방사소음 해석법을 간단한 예제를 통하여 그 특성을 살피고, 실제 함정의 받침대 진동에 의한 수중방사소음의 계산에 적용하여 그 유용성을 보였다.

평판에서 방사되는 소음의 능동구조소음제어를 위한 변환기의 위치결정 (The Determination of Transducer Locations for Active Structural Acoustic Control of the Radiated Sound from Vibrating Plate)

  • 김흥섭;홍진석;이충휘;오재응
    • 한국소음진동공학회논문집
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    • 제12권9호
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    • pp.694-701
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    • 2002
  • In this paper, through the study on locations of structural transducers for active control of the radiated sound from the vibrating plate, the active structural acoustic control (ASAC) system is proposed. And, for the evaluation of the proposed location, the experiment of the active structural acoustic control is implemented using the multi-channel filtered-x LMS algorithm and an additional filter (Acoustic Prediction Filter) to estimate the radiated sound using the acceleration signals of the plate. The structural transducers are piezoceramic actuator (PZT) and accelerometer. PZT is used as an actuator to reduce the vibration and the radiated sound. To maximize the control performance, each PZT actuator is located at the position that has the largest control sensitivity of the plate bending moment in the direction of x and y coordinates and the optimal PZT location is validated experimentally. Also, to find the acoustic prediction filter accurately, two accelerometers are located at the positions that have the largest radiation efficiencies of the plate, and the proposed locations are validated by simulation using the Rayleigh integral. The multi-channel filtered-x LMS algorithm is introduced to control a complex 2-D structural vibration mode. Finding the locations of structural transducers for active structural acoustic control of the radiated sound, the active structural acoustic control (ASAC) system can be presented and validated by experiments using a real time control system.

하중법을 이용한 텐세그리티 구조물의 자기평형 응력 탐색 (Form-finding of Tensegrity Structures with constraints by using Force Method)

  • 정우성;이재홍;강주원
    • 한국공간구조학회논문집
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    • 제11권4호
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    • pp.49-59
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    • 2011
  • 본 논문에서는 제약조건이 고려된 텐세그리티 구조물의 형상 탐색 방법에 있어서 기존의 하중법을 특이값 분해로 정식화 한 새로운 하중법을 제안하였다. 텐세그리티 구조물은 형태의 안정성 유지를 위해 프리스트레스가 도입 되어야하며 이를 위하여 형상 탐색이 수행되어 진다. 또한 실제 구조물로서 활용되기 위해서는 제약조건이 고려되어야한다. 기존의 하중법은 어려운 구조적 개념이 필요하지 않아 접근 방법이 쉽지만 많은 수식을 통해 형상 탐색을 수행하여야 하므로 이로인해 수지상의 오류가 발생할 수 있으며 내력 밀도법을 사용하여 형상 탐색을 수행 할 경우 제약조건에 맞는 가상의 부재(Dummy Element)를 찾는 것이 어렵다는 단점이 있다. 본 연구에서는 기존의 하중법에서 사용하던 수식을 특이값 분해로 정식화하여 수치적 오류를 줄일 수 있는 새로운 하중법을 제안하였다.

건축적 장식과 구조: 장식과 텍토닉의 관계를 중심으로 전통적 장식과 현대 장식 경향의 연계관계에 대한 연구 (Architectural ornament and structure: a study on the links between contemporary ornamental trends and traditional ornament, focusing on the relation between decoration and tectonics)

  • 파비오 다카로
    • 한국실내디자인학회논문집
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    • 제21권6호
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    • pp.158-167
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    • 2012
  • This research began by considering that, although architecture and architectural culture of the last two decades seem to have rediscovered ornament and some recent studies have reconsidered the ornamental issues of contemporary buildings, there is currently some difficulty in providing a synthetic investigation of this topic, because of the complex nature of the contemporary architectural situation. Following this premise, this research provides some reference points for further studies that will aim to expand the understanding, and attempt to classify and hypothesize the future of contemporary ornamental phenomena. Based on the assumption of the historical continuity of ornamental problems, and adopting the relation - both technical and aesthetic - between ornament and structure as one of the crucial issues to link past and present problems, the study firstly defines two categories and two sub-categories concerning the relation between ornament and structure, namely: a) ornament integral with the structure and b) ornament applied to the structure; a1) ornament visually expressing the structure and a2) ornament not visually expressing the structure. The study then reviews the historical development of ornament from ancient times to the present in the light of the above mentioned categories, and finally discusses the principles of traditional and modern ornament thus analyzed in relation to contemporary ornamental trends, as identified in selected case studies. Some common points between past and contemporary experiences are revealed in order to facilitate further investigations. In particular, the analysis shows a certain trend in contemporary architecture for a strong link between ornamental treatment and the structure of the building and a current tendency among contemporary designers to keep the exterior appearance of the building project separate from the design of the rest of the construction.

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Effect of Coordination Environment on the Photophysical Properties of Luminescent Europium(III) Complexes

  • Baek, Nam-Seob;Kim, Yong-Hee;Lee, Dong-Hyun;Seo, Kang-Deuk;Kim, Hwan-Kyu
    • Bulletin of the Korean Chemical Society
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    • 제30권7호
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    • pp.1553-1558
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    • 2009
  • A series of Eu(III) complexes with various neutral ligands (2,2’:6’,2"-terpyridine (T), diglyme (D), 1N-(2-dimethylamino) ethyl)-1N, 2N, 2N-trimethylethane-1,2-diamine (PT), di-(2-picolyl)-amine derivative (HT), and multidentate terpyridine derivative (DT)) were synthesized to investigate the effect of coordination environment on the sensitized luminescence of Eu(III) complexes. The nine coordination sites of the $Eu^{3+}$ ion are occupied by three bidentate carboxylate moieties and one neutral ligand. The highest emission intensity is obtained for $Eu^{3+}$- $[NA]_3$ (PT), due to the difference in energy transfer efficiency and symmetry of the first coordination sphere of $Eu^{3+}$ ion. But, the lowest emission intensity is obtained for $Eu^{3+}$-$[NA]_3$(T). Terpyridine may not play an important role antenna for photosensitizing $Eu^{3+}$ ion. It could be attributed to the weak spectral overlap integral J value between its phosphorescence band and $Eu^{3+}$ion absorption band. Therefore, different coordination environment of $Ln^{3+}$ ion play an important role in providing sensitization of lanthanide ion emission.

A "Dynamic Form-Finding" Approach to Environmental-Performance Building Design

  • Yao, Jia-Wei;Lin, Yu-Qiong;Zheng, Jing-Yun;Yuan, Philip F.
    • 국제초고층학회논문집
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    • 제7권2호
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    • pp.145-151
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    • 2018
  • Newly-designed high-rise buildings, both in China and abroad, have demonstrated new innovations from the creative concept to the creative method. from the creative concept to the creative method. At the same time, digital technology has enabled more design freedom in the vertical dimension. "Twisting" has gradually become the morphological choice of many city landmark buildings in recent years. The form seems more likely to be driven by the interaction of aesthetics and structural engineering. Environmental performance is often a secondary consideration; it is typically not simulated until the evaluation phase. Based on the research results of "DigitalFUTURE Shanghai 2017 Workshop - Wind Tunnel Visualization", an approach that can be employed by architects to design environmental-performance buildings during the early stages has been explored. The integration of a dynamic form-finding approach (DFFA) and programming transforms the complex relationship between architecture and environment into a dialogue of computer language and dynamic models. It allows the design to focus on the relationship between morphology and the surrounding environment, and is not limited to the envelope form itself. This new concept of DFFA in this research consists of three elements: 1) architectural form; 2) integration of wind tunnel and dynamic models; and 3) environmental response. The concept of wind tunnel testing integrated with a dynamic model fundamentally abandons the functional definition of the traditional static environment simulation analysis. Instead it is driven by integral environmental performance as the basic starting point of morphological generation.

Bridging the Gap Between Science and Industry: The Fraunhofer Model

  • Klingner, Raoul;Behlau, Lothar
    • STI Policy Review
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    • 제3권2호
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    • pp.130-151
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    • 2012
  • Fraunhofer was founded in 1949 and grew into Europe's largest application-oriented research organization. Fraunhofer currently employs over 20,000 members in Germany, is internationally networked, and manages an R&D budget of over 1,8 Billion Euros per year. An important step for Fraunhofer to become an integral component of the German innovation system was the introduction of the Fraunhofer Model of financing based on a performance-related system of financial management. The underlying model of the allocation and distribution of public funding to Fraunhofer that is subsequently allotted to specific research groups is one of the success factors of Fraunhofer. Fraunhofer is proud of its decentralized organizational model. Fraunhofer is comprised of 60 Institutes in Germany working in different fields, under one legal framework, and with a strong brand value. Every Fraunhofer Institute is affiliated with a German University and every institute director simultaneously holds a chair at the affiliated university. It is a challenge for the headquarter organization to balance the intended competition of individual Fraunhofer Institutes with complementarity cooperation in science among Fraunhofer-Institutes, especially when coming from different knowledge domains; however, this goal results in a significant advantage. The unique strengths of Fraunhofer offer system solutions in a world with increasingly complex R&D challenges. While growing to become the largest organization on Europe to focus on applied research it is the challenge to remain an agile organization that is flexible in organizational structure. Fraunhofer has reached a well-recognized position in the European innovation landscape. It is often referred to by science and governments as a role model for innovation policy and a key element of the latest successes in the German economy that has recovered quicker from the latest economic crisis than most other western economies. The paper explains Fraunhofer as an organizational paradigm and its underlying management model to elaborate on the challenges of managing a research organization. We wish to show how it is possible to transfer the management model and philosophy of Fraunhofer to innovation systems with different framework conditions and challenges. A universal conclusion may be drawn based on the description of Fraunhofer; however, changes in existing structures and innovation systems cannot be implemented over night.