• 제목/요약/키워드: First passage time

검색결과 139건 처리시간 0.023초

Hierarchical Fuzzy Motion Planning for Humanoid Robots Using Locomotion Primitives and a Global Navigation Path

  • Kim, Yong-Tae
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제10권3호
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    • pp.203-209
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    • 2010
  • This paper presents a hierarchical fuzzy motion planner for humanoid robots in 3D uneven environments. First, we define both motion primitives and locomotion primitives of humanoid robots. A high-level planner finds a global path from a global navigation map that is generated based on a combination of 2.5 dimensional maps of the workspace. We use a passage map, an obstacle map and a gradient map of obstacles to distinguish obstacles. A mid-level planner creates subgoals that help the robot efficiently cope with various obstacles using only a small set of locomotion primitives that are useful for stable navigation of the robot. We use a local obstacle map to find the subgoals along the global path. A low-level planner searches for an optimal sequence of locomotion primitives between subgoals by using fuzzy motion planning. We verify our approach on a virtual humanoid robot in a simulated environment. Simulation results show a reduction in planning time and the feasibility of the proposed method.

브라운 운동을 따르는 열화현상을 이용한 일정스트레스 가속수명시험의 최적설계 (Optimal Design of Constant Stress Accelerated Life Tests Using Degradation Phenomenon Based on a Brownian Motion)

  • 서순근;김갑석;하천수
    • 품질경영학회지
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    • 제26권1호
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    • pp.74-87
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    • 1998
  • This study considers optimal design of accelerated life tests under constant stress using that the first passage time to cross a critical boundary through amount of accumulated degradation has an inverse Gaussian distribution when the degradation process follows to a Brownian motion with positive drift of log linear function of stress. Optimum plans for Type I censoring are derived by minimizing the asymptotic variance of estimated quantiles at the use stress. Sensitivity analyses are also conducted to see how sensitive the optimality criterion is with respect to the uncertainties involved in the guessed values.

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Quantitative Determination of Organic Yield by Continuous Percolation Processes of Bio-wastes at K Composting Plant

  • Seo, Jeoung-Yoon;Jager, Johannes
    • Environmental Engineering Research
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    • 제19권2호
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    • pp.123-130
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    • 2014
  • Percolation is the important process of extracting the soluble constituents of a fine mesh, porous substance by passage of a liquid through it. In this study, bio-wastes were percolated under various conditions through continuous percolation processes, and the energy potential of percolate was evaluated. The representative bio-wastes from the K composting plant in Darmstadt, Germany were used as the sample for percolation. The central objective of this study was to determine the optimal amount of process water and the optimum duration of percolation through the bio-wastes. For economic reasons, the retention time of the percolation medium should be as long as necessary and as short as possible. For the percolation of the bio-wastes, the optimal percolation time was 2 hr and maximum percolation time was 4 hr. After 2 hr, more than two-thirds of the organic substances from the input material were percolated. In the first percolation process, the highest yields of organic substance were achieved. The best percolation of the bio-wastes was achieved when the process water of 2 L for the first percolation procedure and then the process water of 1.5 L for each further percolation procedure for a total 8 L for all five procedures were used on 1,000 g fresh bio-waste. The gas formation potentials of 0.83 and $0.96Nm^3/ton$ fresh matter (FM) were obtained based on the percolate from 1 hr percolation of 1,000 g bio-waste with the process water of 2 L according to the measurement of the gas formation in 21 days (GB21). This method can potentially contribute to reducing fossil fuel consumption and thus combating climate change.

복합용도개발 내부공간의 외부공간 지향성에 관한 계획특성 연구 (A Study on the Planning Characteristics of Interior Space Aiming for the Exterior Space in Mixed-Use Development)

  • 김석기;성이용
    • 한국실내디자인학회논문집
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    • 제22권3호
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    • pp.43-51
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    • 2013
  • The purpose of this study is analysing the characteristics of interior space aiming for the exterior space in mixed-used development. The range of this study is limited as passage, department store, shoppingmall and Mixed Use Development. The method of this study is as follows. First, analysing the 7 samples of the interior space aiming for the exterior space in MXD through the framework of public character categorized as 5 factors, accessibility, openness, comfort properties, connectivity, convenience in use. Second, drawing a conclusion from the precedent step. The result of this study is as follows. First, the interior space has become bigger with time. And the public character is expanded with having the same structure of the city space. Second, the interior space solves the problem of the exterior space of city but prefers the same factors with the exterior space. Third, the street in the interior space has the characteristics of openness and comfort properties through diversification. And the open space is planned in various parts of the MXD and has the character of accessibility and connectivity.

한국 전통음식 통합검색 시스템 구축을 위한 통과의례음식 연구 (A Study on the Traditional Korean Rites Foods for the Construction of a Traditional Korean Food Data Integration System)

  • 신승미;손정우
    • 한국식품영양학회지
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    • 제21권3호
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    • pp.344-354
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    • 2008
  • The traditional ritual foods of Korea have developed with for many years, and differ by locality, family customs and religious characteristics. In an efforts to establish the database on that addresses the difficult issue of a classification system for traditional Korean foods, we have conducted a survey of a traditional Korean ritual foods. In the database, typical 10 rites are represented, covering birth to death, these are birth, the hundredth day after birth, the first birthday, the commemoration of finishing books(graduation), the coming of age ceremony, marriage, the birthday feast for an old man, the 60th wedding anniversary, the funeral, and the memorial service. For each rite, the appropriate traditional Korean foods are classified into 6 categories-main dishes, side dishes, tteok lyou, hangwa lyou, eumchung lyou and the others. Some of these have varied considerably with the passage of time, and some have since disappeared. This database provides a basis for generational transmission, preservation and development of traditional Korean ritual foods as one of the components traditional Korean culture.

해상 교통량의 효율적 관리 방안에 관하여 (II) - 일반 수로의 경우 - (A Study on Optimum Control of Marine Traffic(II) - In the Domain of Passage -)

  • 윤명오;이철영
    • 한국항해학회지
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    • 제15권3호
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    • pp.1-11
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    • 1991
  • As increasing needs of marine transportation , world merchant fleet and ship's size were enlarged and it caused frequent disasters in human lives and natural environment. By the reason of the above, they started to establish the Vessel Traffic System (VTS) at the European coast in 1960' and most of advanced contries established and managed it to prevent the sea traffic accidents in these days. The concept of traffic control at sea can be divided into three types. First, the initial gathering of informations about ship's identity and movement etc.. Second, monitoring of the traffic flow and amendment of instructions. Third , organization and direction of ships by allocating routes and speeds. Where the goal of traffic control is safety of traffics and developing effectiveness of navigation channel, if traffic volume is less tan channel capacity then the above first or second level of control would be sufficient but if it is bigger than that , more positive policy of control should be adopted as same as third type of the above. In this paper where the strategy of VTS is focused on the control of traffic density to be spread equality, as possible , all over the navigation channels and also improvement of effectiveness , it suggests algorithm to assign the vessels to the channels with balanced traffic density , and other algorithms using D.P. to sequence the vessels assigned to one channel in optimum order which decreases the mean waiting time in sense of channel effectiveness with numerical examples.

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Laboratory passage and characterization of an isolate of Toxoplasma gondii from an ocular patient in Korea

  • Chai, Jong-Yil;Lin, Aifen;Shin, Eun-Hee;Oh, Myoung-Don;Han, Eun-Taek;Nam, Ho-Woo;Lee, Soon-Hyung
    • Parasites, Hosts and Diseases
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    • 제41권3호
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    • pp.147-154
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    • 2003
  • Toxoplasma gondii tachyzoites were isolated from the blood of an ocular patient, and have been successfully passaged in the laboratory, for over a year, by peritoneal inoculation in mice. The isolated parasite was designated the Korean Isolate-1 (KI-1) and its characteristics were compared with those of the RH strain, a well-known virulent strain originating from a child who suffered from encephalitis. The morphology, pathogenicity, infectivity and cell culture characteristics of the KI-1 were similar to those of the RH strain. Both RH and KI-1 antigens were detected by an anti-T gondii monoclonal antibody (mAb), Tg563, against the major surface protein SAG1 (30 kDa), whereas no reaction was observed against an anti-Neospora caninum mAb, 12B4. The KI-1 was confirmed as an isolate of T. gondii. A long-term laboratory maintenance and characterization of a local T gondii isolate is reported for the first time in the Republic of Korea.

미니멀 아트의 장소특정성의 한계 : 도널드 저드의 작품을 중심으로 (Limitations of Site-Specificity in Minimal Art: Focusing on Donald Judd's works)

  • 박미예
    • 대한건축학회논문집:계획계
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    • 제35권2호
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    • pp.93-104
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    • 2019
  • Minimal art, which began to flourish in the mid-1960s, explores perceptual situations caused by the involvement of objects in given site contexts. This has led to the mentions of minimal art as a site-specific art, but its limitations have also been pointed out. This study specifically addresses the limitations of minimal art as a site-specific art with two perceptual points of view. First, according to Michael Fried, situations described as 'now here' focus largely on the bodily experiences of a place. However, they do not rooted in specific time and space of a certain place. Second, the unique characteristics of a certain place are excluded from the perception of the body which occupies the passage of time. Self-sufficient algorithm, which is far from site-specific conditions, is the autonomous system creating the period in the way of arrangement of objects. In addition, Minimal art regards a body only as the objectivity excluding the subjectivity which is essential creating meaning in a place. In the latter part of the article, these features are dealt with through Donald Judd's works. This study on site-specificity also provides a new perspective on the discussion of Minimal architecture and Minimal landscape.

공간의 시각적 이해과정에 나타난 성별 주시특성에 관한 연구 (A Study on Observation Characteristics by Sex shown in the process of Visual Appreciation of Space)

  • 김종하
    • 한국실내디자인학회논문집
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    • 제22권5호
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    • pp.152-161
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    • 2013
  • This study is about the visual appreciation by sex with the analysis of time range of observing data which was got through observation experiment with the space of lobby in hospitals. The observation data of the subjects who observed the space include the frequency and time, through which the process of visual appreciation could be evaluated with the definition of the frequency and the time of observation. First, the fact that men had higher frequency of observation than women means the former had more movement than the latter, and another fact of their fewer times can be understood as the time of their staying was shorter. That is, even though the men had more movements of sight, they showed the feature of staying shorter. Second, the rate high and low of observation frequency and times made it possible for observation characteristics to be defined as 'intensive search' 'active search' 'fixed concentration' and 'search wandering.' The definition of understanding this process of visual appreciation can be available for a frame of effective analysis of observation characteristics according to the passage of time. Third, the intense search is the case of 'high frequency' having the feature of high visual appreciation owing to the active visual actions for acquiring information. Men were found to have more intense search which decreased gradually as time passed, while women showed the feature of many times of intense search. Fourth, it was found that with many observation data in a certain range of time the subjects had fixed concentration, where women were found to have repetitive fixed concentration along with the change of observation time while men were seen to have more observation tendency for fixed concentration. Fifth, at the cross tabulation of frequency and times, men had the feature of dispersed visual appreciation while women had more distinction between fixation and movement, which revealed that there is surely the difference between men and women in the process of visual appreciation.

시간흐름을 고려한 특징 추출과 군집 분석을 이용한 헬스 리스크 관리 (Health Risk Management using Feature Extraction and Cluster Analysis considering Time Flow)

  • 강지수;정경용;정호일
    • 한국융합학회논문지
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    • 제12권1호
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    • pp.99-104
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    • 2021
  • 본 논문에서는 시간 흐름을 고려한 특징추출과 군집분석을 이용한 헬스 리스크 관리를 제안한다. 제안하는 방법은 세단계로 진행한다. 첫 번째는 전처리 및 특징추출 단계이다. 이는 웨어러블 디바이스를 이용하여 라이프로그를 수집하여 불완전데이터, 에러, 잡음, 모순된 데이터를 제거하며 결측 값을 처리한다. 그 다음 특징추출을 위해 주성분 분석을 통해 중요 변수를 선택하고, 상관계수와 공분산을 통해 데이터 간의 관계와 유사한 데이터들의 분류를 진행한다. 또한 라이프로그에서 추출한 특징을 분석하기 위해 시간의 흐름을 고려하여 K-means 알고리즘을 통해 동적 군집을 진행한다. 새로운 데이터는 오차 제곱합의 증가분을 기반으로 유사성 거리 측정 방법을 통해 군집을 진행하고, 시간의 흐름을 고려하여 군집에 대한 정보를 추출한다. 따라서 특징 군집을 통해 헬스 의사결정 시스템을 이용하여 신체적 특성, 생활습관, 질병여부, 헬스케어 이벤트 발생위험, 예상 정도 등의 요소를 통해 리스크를 관리할 수 있다. 성능평가는 Precision, Recall, F-measure을 사용하여 제안하는 방법과 퍼지방법, 커널기반 방법을 비교한다. 평가결과 제안하는 방법이 우수하게 평가된다. 따라서 제안하는 방법을 통해 유병자와의 유사도를 이용하여 정확한 사용자의 잠재적 건강 위험을 예측 및 적절한 관리가 가능하다.