• 제목/요약/키워드: Large scaling factors

검색결과 29건 처리시간 0.02초

유전알고리즘을 사용한 HVDC용 퍼지 제어기의 설계 (Tuning of Fuzzy Logic Current Controller for HVDC Using Genetic Algorithm)

  • Jong-Bo Ahn;Gi-Hyun Hwang;June Ho Park
    • 대한전기학회논문지:전력기술부문A
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    • 제52권1호
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    • pp.36-43
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    • 2003
  • This paper presents an optimal tuning method for Fuzzy Logic Controller (FLC) of current controller for HVDC using Genetic Algorithm(GA). GA is probabilistic search method based on genetics and evolution theory. The scaling factors of FLC are tuned by using real-time GA. The proposed tuning method is applied to the scaled-down HVDC simulator at Korea Electrotechnology Research Institute(KERI). Experimental result shows that disturbances are well-damped and the dynamic performances of FLC have the better responses than those of PI controller for small and large disturbances such as ULTC tap change, reference DC current change and DC ground fault.

DEM을 이용한 수로망의 형태학적 표현 (Morphological Representation of Channel Network by Dint of DEM)

  • 김주철;김재한
    • 한국수자원학회논문집
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    • 제40권4호
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    • pp.287-297
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    • 2007
  • DEM을 이용하여 국부경사와 기여면적 사이의 규모에 따른 거동특성을 조사하여 면적한계기준과 경사-면적한계 기준이 상호보완적인 형태의 수로망 추적절차를 제시하였다. 상기방법과 현장자료에 대한 적용을 통하여 유역의 경사는 공간적으로 대규모의 산포경향을 갖는 지형인자임을 확인할 수 있었다. 양자의 규모에 따른 거동특성권역에 따라 지면의 형상은 발산지형과 수렴지형으로 분류될 수 있었다. 본 연구에서 제시한 수로망 동정 절차를 설마천 시험 유역에 대하여 수행한 결과 유역의 동적 거동을 확인할 수 있었다. 또한 이로부터 지형도를 이용한 수작업에 기초한 방법에 비하여 하천두부의 거동과 수로망의 동적특성을 잘 표현하고 있음을 볼 수 있었다.

정성적/정성적 디자인 가치의 누적평가방법에 관한 기초 연구 (A Study on the Accumulative Evaluation of Qualified Quantified Values in Industrial Design)

  • 박대순;우흥룡
    • 디자인학연구
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    • 제3권1호
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    • pp.17-33
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    • 1990
  • Evaluation plays an essential role in design activity. Many theorist have agreed that designing involves problem solving or decision making. In evaluation, designers attempt to determine the value of a particular proposal arrived at by synthesis. And the results of designing, the product, is evaluated twice, objectively and subjectively.Alternatives in $$\mu$ti-objective decision problems generally possess numerous attributes by which they can be described and compared. The evaluation factors include all attributes that have levels specified by quantitative and qualitative objectives. However since qualitiative factors are difficult to quantify as $$\mu$eral estmates, these factors have tended to be ignored without regard for their importance to human content. Therefore we need some study that convert qualitative attributes into quantitative scale values. Following to Thurstone' s Psychological scaling methods (The method of successive intervals), attribute values of TV set are assigned by rating scale methods. The method of successive intervals, like the method of equal-appearing intervals, requires but a single judgement from each subject for each statement to be scaled. It is, therefore, a convinient method to use when the number of to be scaled is large. We make the assumtion that those cu$$\mu$ative proportion distributions are normal for each statement when they are projected on the unknown psychological continuum. In this study, we have determined the scale values of 42 statements of TV set by the method of successive intervals. Then we can apply a test of internal consistency similar to that used with the method of paired comparisons. We have as our absolute average deviation, -1.748/252= -0.0069. We have reason to believe that our scale values are consistent with the empirical data, because these discrepanicies are very small.

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축소모델과 실모델 면진베어링의 성능실험에 관한 연구 (A Study on Testing of 1/4-scale and Full-size Seismic Isolation Bearings)

  • 정민기;정지만;김두훈
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1996년도 춘계학술대회논문집; 부산수산대학교, 10 May 1996
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    • pp.194-202
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    • 1996
  • An approach to increase the seismic resistance of large structures is to reduce the seismic forces, to which structures are subjected by base isolation systems. The anti-seismic performance of base-isolated beatings has been verified experimentally by shaking table tests. However, it may be difficult to perform the tests for the full-scale beatings of base-isolated structures. Therefore, the test program was designed to evaluate the reliability and properties of the beatings under a range of loading conditions including axial stress, loading frequency and direction, and temperature. The effects of scale were also evaluated by comparing the results of the 1/4-scale beatings with those from the full-scale bearings, and the ultimate behavior of both types of bearings with evaluated through a series of roll-out tests. This report draws comparisons among the different tests and bearings to determine the importance of various factors including load history, axial stress, and frequency. Comparisons between the 1/4-scale bearings were difficult because of the scaling effects in manufacturing and thermal radiation, but qualitative results from the 1/4-scale bearings can certainly be extrapolated the full-scale bearings.

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Robotic Surgery in Cancer Care: Opportunities and Challenges

  • Mohammadzadeh, Niloofar;Safdari, Reza
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권3호
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    • pp.1081-1083
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    • 2014
  • Malignancy-associated mortality, decreased productivity, and spiritual, social and physical burden in cancer patients and their families impose heavy costs on communities. Therefore cancer prevention, early detection, rapid diagnosis and timely treatment are very important. Use of modern methods based on information technology in cancer can improve patient survival and increase patient and health care provider satisfaction. Robot technology is used in different areas of health care and applications in surgery have emerged affecting the cancer treatment domain. Computerized and robotic devices can offer enhanced dexterity by tremor abolition, motion scaling, high quality 3D vision for surgeons and decreased blood loss, significant reduction in narcotic use, and reduced hospital stay for patients. However, there are many challenges like lack of surgical community support, large size, high costs and absence of tactile and haptic feedback. A comprehensive view to identify all factors in different aspects such as technical, legal and ethical items that prevent robotic surgery adoption is thus very necessary. Also evidence must be presented to surgeons to achieve appropriate support from physicians. The aim of this review article is to survey applications, opportunities and barriers to this advanced technology in patients and surgeons as an approach to improve cancer care.

Tabu Search를 이용한 TCSC의 점호각 제어용 퍼지 제어기의 설계 (Design of Fuzzy Controller for Firing Angle of TCSC Using Tabu Search)

  • 김우근;황기현;문경준;김형수;박준호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 A
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    • pp.37-39
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    • 2000
  • This paper describes the application of Fuzzy Logic Controller (FLC) to Thyristor Controlled Series Capacitor (TCSC) which can have significant impact on Power system dynamics. The function of the FLC is to control the firing angle of the TCSC. We tuned the scaling factors of the FLC using Tabu Search. The proposed FLC is used for damping the low frequency oscillations caused by disturbances such as the sudden changes of small of large loads or the outages in the generators or transmission lines. To evaluate usefulness of the proposed FLC. we performed the computer simulation for single-machine infinite system. The response of FLC is compared with that of PD controller optimized using Tabu Search. Simulation results that the FLC shows the better control performance than PD controller.

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과도 안정도 향상을 위한 TCSC의 점호각 제어용 퍼지제어기의 설계에 Tabu 탐색법의 적용 (Application of Tabu Search in Design of Fuzzy Controller for Firing Angle of TCSC Improving Transient Stability)

  • 김우근;황기현;김형수;박준호;박중근
    • 대한전기학회논문지:전력기술부문A
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    • 제50권12호
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    • pp.561-567
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    • 2001
  • This paper describes the application of Fuzzy Logic Controller (FLC) to Thyristor Controlled Series Capacitor (TCSC) which can have significant impact on power system dynamics. The function of the FLC is to control the firing angle of the TCSC. We tuned the scaling factors of the FLC using Tabu Search. The proposed FLC is used for damping the low frequency oscillations caused by disturbances such as the sudden changes of small or large loads or the outages in the generators or transmission lines. To evaluate usefulness of the proposed FLC, we performed the computer simulation fur single-machine infinite system. The response of FLC is compared with that of PD controller optimized using Tabu Search. Simulation results that the FLC shows better control performance than PD controller.

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A Multi-Stage Convolution Machine with Scaling and Dilation for Human Pose Estimation

  • Nie, Yali;Lee, Jaehwan;Yoon, Sook;Park, Dong Sun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제13권6호
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    • pp.3182-3198
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    • 2019
  • Vision-based Human Pose Estimation has been considered as one of challenging research subjects due to problems including confounding background clutter, diversity of human appearances and illumination changes in scenes. To tackle these problems, we propose to use a new multi-stage convolution machine for estimating human pose. To provide better heatmap prediction of body joints, the proposed machine repeatedly produces multiple predictions according to stages with receptive field large enough for learning the long-range spatial relationship. And stages are composed of various modules according to their strategic purposes. Pyramid stacking module and dilation module are used to handle problem of human pose at multiple scales. Their multi-scale information from different receptive fields are fused with concatenation, which can catch more contextual information from different features. And spatial and channel information of a given input are converted to gating factors by squeezing the feature maps to a single numeric value based on its importance in order to give each of the network channels different weights. Compared with other ConvNet-based architectures, we demonstrated that our proposed architecture achieved higher accuracy on experiments using standard benchmarks of LSP and MPII pose datasets.

롤투롤 공정을 활용한 평판형 분리막의 대면적 제조 연구 (Scale-up Fabrication of Flat Sheet Membrane by Using a Roll-to-Roll Process)

  • 백동혁;유영민;김인철;박유인;남승은;조영훈
    • 멤브레인
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    • 제34권1호
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    • pp.79-86
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    • 2024
  • 고분자 분리막의 대표적인 형태 중 하나인 평판형 분리막은 제조가 용이하여 실험실에서 분리막 소재 연구에서부터 실제 상용 분리막 생산에 이르기까지 널리 활용되는 분리막의 형태이다. 정밀여과 및 한외여과 등에 사용되는 평판형의 다공성 고분자 분리막은 주로 상분리 공정을 통해 제조할 수 있으며, 여기에는 비용매 유도 및 증기 유도 상분리 공정이 활용된다. 그러나 상분리 공정 특성상 주변 환경과 실험자에 따라 샘플 간 편차가 쉽게 발생하여 재현성의 확보가 어려운 점이 있다. 따라서 개발된 제조기술을 스케일업 및 재현성 확보를 위해 제어된 환경에서 연속식 대면적 제조가 가능한 롤투롤 제조장치가 필요하며, 본 연구에서는 실험실 스케일의 제조기술을 나이프 및 슬롯다이 롤투롤 공정으로 스케일 업 했을 때 나타나는 제조 환경 차이에 따른 분리막의 특성 변화를 비교하였다. 최종적으로 연속식 제조공정 인자에 대한 최적화를 통해 대면적 제조 시 분리막의 균일성을 확보하였다.

모형의 모형화 기법을 이용한 1g 진동대 실험을 위한 상사법칙의 유효성 검증 (Verification of Similitude Law for 1g Shaking Table Tests through Modeling of Models)

  • 황재익;김성렬;장인성;김명모
    • 한국지반공학회논문집
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    • 제20권9호
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    • pp.91-103
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    • 2004
  • 지반-유체-구조물 시스템에 대한 1g 진동대 실험을 위한 상사법칙의 유효성을 검증하기 위하여 일련의 모형실험을 수행하였다. 크기가 서로 다른 3가지의 모형에 대한 실험결과 분석에는 lai가 제안한 상사법칙뿐만 아니라 과잉간극수압 발생을 위한 정상상태개념도 적용하여 각 크기의 모형이 예측하는 안벽시스템의 거동을 서로 비교하였다. 그 결과, 가속도와 과잉간극수압, 그리고 변위 응답의 경우, 가장 작은 모형벽체와 가장 큰 모형벽체는 비슷한 값을 예측한 반면, 중간크기의 모형벽체는 공진현상으로 인해 엉뚱하게 큰 값을 예측하였다. 또한 벽체의 수직침하와 회전각은 모형의 크기와 관계없이 모형벽체시스템의 크기가 증가할수록 증가하는 경향을 나타내었다.