• 제목/요약/키워드: Belief Function

검색결과 129건 처리시간 0.027초

Dempster-Shafer 증거 이론을 이용한 회전익 항공기 착륙장치의 FMEA (FMEA for rotorcraft landing system using Dempster-Shafer evidence theory)

  • 나성현;소희섭
    • 한국산학기술학회논문지
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    • 제22권2호
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    • pp.76-84
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    • 2021
  • 품질보증활동은 양산단계에서 위험 식별을 기반으로 품질에 영향을 주는 인자를 확인할 수 있다. 위험 식별은 고장 분석을 통해 이루어지며, 회전익 항공기 착륙장치에 대한 고장 분석 방법은 고장 유형 영향 분석(FMEA)으로 선정하였다. FMEA는 고장 유형에 대해서 심각도, 발생도, 검출도에 대한 정보를 결합하여 품질에 영향을 미치는 인자를 확인하는 방법이다. FMEA 결과는 위험도를 통해 고장 우선순위를 결정한다. 하지만 심각도, 발생도, 검출도에 대한 중요도는 동일하게 구성된다. Dempster-Shafer 증거 이론은 경험과 주관이 반영된 의견에 대해서 불확실성 분석을 수행한다. 또한, Dempster-Shafer 증거 이론은 믿음 함수와 개연성 함수를 구성할 수 있으며, 믿음 함수와 개연성 함수를 통해 가설의 믿음 정도, 신뢰도를 확인할 수 있다. 회전익 항공기 착륙장치는 이륙 및 착륙 시 충격을 받는 구성품으로, 양산단계에서 고장 유형을 관리하는 것이 중요하다. 본 논문에서는 회전익 항공기 착륙장치의 고장 유형에 대한 위험도 분석을 위해 Dempster-Shafer 증거 이론을 이용한 FMEA를 제안하고, 고장 우선순위를 결정한다. 결과는 믿음 함수 및 개연성 함수 곡선을 통해 도출한다.

INCORPORATING PRIOR BELIEF IN THE GENERAL PATH MODEL: A COMPARISON OF INFORMATION SOURCES

  • Coble, Jamie;Hines, J. W esley
    • Nuclear Engineering and Technology
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    • 제46권6호
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    • pp.773-782
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    • 2014
  • The general path model (GPM) is one approach for performing degradation-based, or Type III, prognostics. The GPM fits a parametric function to the collected observations of a prognostic parameter and extrapolates the fit to a failure threshold. This approach has been successfully applied to a variety of systems when a sufficient number of prognostic parameter observations are available. However, the parametric fit can suffer significantly when few data are available or the data are very noisy. In these instances, it is beneficial to include additional information to influence the fit to conform to a prior belief about the evolution of system degradation. Bayesian statistical approaches have been proposed to include prior information in the form of distributions of expected model parameters. This requires a number of run-to-failure cases with tracked prognostic parameters; these data may not be readily available for many systems. Reliability information and stressor-based (Type I and Type II, respectively) prognostic estimates can provide the necessary prior belief for the GPM. This article presents the Bayesian updating framework to include prior information in the GPM and compares the efficacy of including different information sources on two data sets.

중국 하북성 마을제 연구 - 하북성조현범장이월이룡패회중룡신적여인(河北省趙縣范庄二月二龍牌會中龍神的與人) - (A Study of Local Festival for the China Hebeisheng)

  • 박광준
    • 헤리티지:역사와 과학
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    • 제36권
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    • pp.347-377
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    • 2003
  • China is a country with large agricultural areas and subject to frequent calamities. Drought is the top of them. It has been a key problem for development of agriculture in the country. In the long struggle against drought, Chinese have accumulated many rational and irrational experiences. The Dragon Kings Belief, which is popular in North China and discussed in a thesis, is one of their irrational experiences. The belief was passed together with Buddhism from India to China in the Tang Dynasty. After it settled down, it was incorporated with the local five dragons belief and a set of beliefs in dragon kings came into existence. The emergence of the dragon kings belief ended the history that the title of rain got was not clear in China and Dragon kings finally got the status. Irrigation is the lifeblood of agriculture in China. In a Chinese mind, Dragon kings are the most important gods who take charge of rain and thus offer the lifeblood. In understanding the nature and characteristics of Chinese traditional culture, it is important for us to make clear the origin and evolution of the belief, find out its nature, function and operation. In the every year beginning of February of the Fanzhuang calendar in the people of Hebeisheng Zhaoxian, would all hold a festival to offer sacrifices to the $^{{\circ}TM}^{\prime}longpai$. Longpai was regarded as the core of the temple fair, thus the native sons came to call this festival; "longpaihui". In this region the'Fanzhuang longpaihui'developed into a well knownand grand temple fair. It was able to attract numerous pilgrims with its special magic power, occupying a place in $China^{{\circ}TM}$ 'eryueer'festival with festive dragon activities. The dragon is a common totem among Chinese nationals. The belief worship of the dragon dates from the start time of primitive societies. Dragon oneself the ancients worship's thunder lightning. In the worship of the great universe, at first afterwards this belief with the tribe's totem worships to combine to become the animal spirit. In ancient myths legends, along with folk religion and beliefs all hold a very important position. The longpaihui is a temple fair without a temple; this characteristic is a distinction between longpaihui and other temple fairs. As for longpaihui must of the early historical records are unclear. The originator of a huitou system has a kind of organized form of the special features rather, originator of a huitou not fix constant, everything follows voluntarily principle, can become member with the freedom, also can back at any time the meeting. There is a longpaihui for 'dangjiaren', is total representative director in the originator of a huitou will. 'banghui' scope particularly for extensive, come apparently every kind of buildup that help can return into the banghui, where is the person of this village or outside village of, the general cent in banghui work is clear and definite, for longpaihui would various businesses open smoothly the exhibition provides to guarantees powerfully. Fanzhuang longpaihui from the beginning of February to beginning six proceed six days totally. The longpai is used as the ancestry absolute being to exsits with the community absolute being at the same time in fanzhuang first took civil faith, in reality is a kind of method to support social machine in native folks realize together that local community that important function, it provided a space, a kind of a view to take with a relation, rising contact, communication, solidify the community contents small village, formation with fanzhuang. The fanzhuang is used as supplies for gathering town, by luck too is this local community trade exchanges center at the same time therefore can say the faith of the longpai, in addition to its people's custom, religious meaning, still have got the important and social function. Moreover matter worthy of mentioning, Longpai would in organize process, from prepare and plan the producing of meeting every kind of meeting a longpeng of the matter do, all letting person feeling is to adjust the popular support of, get the mass approbation with positive participate. Apart from the originator of a huitou excluding, those although not originator of a huitou, however enthusiasm participate the banghui of its business, also is too much for the number.

2차원 레이저 거리측정기를 활용한 신뢰도 전파 스테레오 정합 기법 (Belief propagation stereo matching technique using 2D laser range finder)

  • 김진형;고윤호
    • 한국멀티미디어학회논문지
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    • 제17권2호
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    • pp.132-142
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    • 2014
  • 스테레오 카메라는 거리정보의 획득 이외에 대상의 부가적인 정보를 획득할 수 있는 장점이 있어 향후 지능 로봇 시스템에 필수적인 센서로 각광받고 있다. 하지만 건물의 벽면과 같이 대상 표면에 반복적인 무늬가 있는 영역, 질감도가 낮은 영역 등에서는 기존의 기법으로는 정합이 불가능하다. 이러한 한계를 극복하기 위해 본 논문에서는 2D 레이저 거리 측정기를 활용해 국소적으로 획득된 거리정보를 신뢰도 전파스테레오 정합 기법에 융합하여 정합 성능을 향상시키는 기법을 제안한다. 제안된 기법은 기존의 신뢰도 전파 스테레오 정합 기법의 국부-명백함수에 Quad-tree 기반 영상분할 정보를 참조하여 레이저 측정 정보를 추가하고, 영상의 과분할 정보를 참조하여 국부-적합성 함수를 계산한다. 제안한 기법을 모의 실험영상과 실영상에 적용한 결과 질감도가 낮은 영역에서도 부분적으로 거리정보를 획득할 수 있었으며, 영역분할 정보의 사용으로 깊이 정보의 불연속성이 유지되는 것을 관찰할 수 있었다.

Deep Belief Network를 이용한 뇌파의 음성 상상 모음 분류 (Vowel Classification of Imagined Speech in an Electroencephalogram using the Deep Belief Network)

  • 이태주;심귀보
    • 제어로봇시스템학회논문지
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    • 제21권1호
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    • pp.59-64
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    • 2015
  • In this paper, we found the usefulness of the deep belief network (DBN) in the fields of brain-computer interface (BCI), especially in relation to imagined speech. In recent years, the growth of interest in the BCI field has led to the development of a number of useful applications, such as robot control, game interfaces, exoskeleton limbs, and so on. However, while imagined speech, which could be used for communication or military purpose devices, is one of the most exciting BCI applications, there are some problems in implementing the system. In the previous paper, we already handled some of the issues of imagined speech when using the International Phonetic Alphabet (IPA), although it required complementation for multi class classification problems. In view of this point, this paper could provide a suitable solution for vowel classification for imagined speech. We used the DBN algorithm, which is known as a deep learning algorithm for multi-class vowel classification, and selected four vowel pronunciations:, /a/, /i/, /o/, /u/ from IPA. For the experiment, we obtained the required 32 channel raw electroencephalogram (EEG) data from three male subjects, and electrodes were placed on the scalp of the frontal lobe and both temporal lobes which are related to thinking and verbal function. Eigenvalues of the covariance matrix of the EEG data were used as the feature vector of each vowel. In the analysis, we provided the classification results of the back propagation artificial neural network (BP-ANN) for making a comparison with DBN. As a result, the classification results from the BP-ANN were 52.04%, and the DBN was 87.96%. This means the DBN showed 35.92% better classification results in multi class imagined speech classification. In addition, the DBN spent much less time in whole computation time. In conclusion, the DBN algorithm is efficient in BCI system implementation.

어머니가 인지한 유아의 식품기호도 형성 요인, 식사 섭취 개선 노력과 식품선택 신념에 관한 연구 (Mothers' Perceptions on Preschool Children's Food Preference, Efforts in Improving Food Intake and Their Beliefs in Food Selection)

  • 정영혜;윤진숙;박동연
    • 대한지역사회영양학회지
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    • 제11권6호
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    • pp.714-724
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    • 2006
  • In an attempt to investigate mothers' perceptions of factors affecting preschool children's food preferences, their policy improving food intake and belief in food selection, in-depth interviews with 30 mothers who had preschool children were conducted in Daegu and Busan. The interviews were tape-recorded and the contents of interviews were analysed by researchers. Most mothers and children liked meats. It was found that children usually disliked vegetables such as onions, carrots, and green onions. Mothers perceived that many factors affected their children's food preferences: mothers' and fathers' food preferences, food offering at meals. mothers' food intake during pregnancy, children's food intake during weaning period, heredity peer pressure, and advertisements on television. Mothers made efforts to improve childrens food intakes in many ways: change of cooking method, emphasizing function of nutrients and food for health, conciliation and enforcement, and comparison to other children. The most affecting belief for mothers in food selection was family members' food preference. Health, balance in nutrient intake degree of food processes food additives, chemicals, convenience, diversity, and economy were also important beliefs to select food. Convenience was especially the primary belief in choosing and preparing children's snacks. Mothers offered frozen dumplings and meat, instant noodles, tuna, and ham for snacks for convenience. These results showed that mothers understood many aspects affecting children's food preference tried to improve children s food intakes and had several beliefs in food selection. We concluded that it is necessary to give information for mothers to make healthy snacks in a short time and chance to learn cooking skills.

Bayesian Estimation of Shape Parameter of Pareto Income Distribution Using LINEX Loss Function

  • Saxena, Sharad;Singh, Housila P.
    • Communications for Statistical Applications and Methods
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    • 제14권1호
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    • pp.33-55
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    • 2007
  • The economic world is full of patterns, many of which exert a profound influence over society and business. One of the most contentious is the distribution of wealth. Way back in 1897, an Italian engineer-turned-economist named Vilfredo Pareto discovered a pattern in the distribution of wealth that appears to be every bit as universal as the laws of thermodynamics or chemistry. The present paper proposes some Bayes estimators of shape parameter of Pareto income distribution in censored sampling. Asymmetric LINEX loss function has been considered to study the effects of overestimation and underestimation. For the prior distribution of the parameter involved a number of priors including one and two-parameter exponential, truncated Erlang and doubly truncated gamma have been contemplated to express the belief of the experimenter s/he has regarding the parameter. The estimators thus obtained have been compared theoretically and empirically with the corresponding estimators under squared error loss function, some of which were reported by Bhattacharya et al. (1999).

간호관리자 역할의 성공적 수행을 위한 연구 (Nursing Managemant, Strategies for its success)

  • 김소인
    • 대한간호
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    • 제29권5호
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    • pp.46-53
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    • 1991
  • In the past, management had been done over nurses rather than nursing and this brought the existence of general manager and as a result, nurse-manager's position and role are being threatend. For the up-bringing of nursing to firm professional recognition in the 21st century, it is firmly believed that nursing managers are to be in the position to play the role of general manager with professional qualifications; personal qualities and exact understandings on the role and function of each tier group under her/his management. 124 top(3 nursing superintendents), middle-range(23 supervisors) and unit managers(98 head-nurses) from 3 university hospitals in Seoul were interviewed in order to investigate their belief in the role, professional qualifications, personal qualities as well as the strategy for the development of their leadership qualities. The frame of reference for the interview were developed by the researcher in reference to relevant literatures. It was the common belief that qualifications o[ top-managers and mid-managers require an educational background of master's preparation or higher and clinical career for at least 15 years for top-managers and 5 -10 years for mid-managers. The personal qualities required by nurse managers include; leadership, initiative, judgement, self-confidence, flexibility, open-mindedness and strong motivation. Achievment-orientedness would greatly help them become excellent managers. On the other hand, [or more effective management, managers of each teir group are to fully understand their role and perform "their job responsibilities ie. Top managers are supposed to study with emphasis on organization, function and conceptual s~ill while mid-managers concentrate their effort on the development of skills for direction, guidance and human relationship. Unit managers also supposed to have abilities to manage their function with emphasis on development of clinical performance skill, for direction on operative aspects. The strategies for the development of leadership qualities include program-planning at individual instutional level as well as local, national and international level. Nurse-managers are to be motivated and encouraged to participate in the programs in order to effectively communicate within tier groups.oups.

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함수 개념의 이해에 대한 비교 연구 (A Cross-National Study of Calculus Students' Understanding of the Funciton Concept)

  • 윤석임
    • 대한수학교육학회지:수학교육학연구
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    • 제8권2호
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    • pp.753-762
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    • 1998
  • 본 논문은 한국과 미국의 서로 다른 교육 체제와 교육환경에서 고등학교 과정을 마치고 미국 남서부에 있는 한 주립대학의 첫 학기 calculus 과목을 이수하고 있는 학생들의 함수 개념에 관한 이해도를 비교 조사한 결과를 다룬다. 또한 미적분학 강의에 선행되는 함수 개념에 대하여 학생들이 실제 알고 있는 것은 무엇이고 또 두 그룹간에 함수의 이해도 성취도의 차이는 무엇에 기인하는가를 조사함으로써 두 나라의 수학교사와 교육과정 개발 담당자에게 하나의 관점을 제시하고자 한다. 함수의 개념에 관한 학생들의 다양한 인지적인 반응은 Dunbinsky(1997)의 이론을 통하여 분석하였고, 두 그룹의 우수한 학생들 간의 함수와 관련된 문제해결 능력의 성취도 차이는 지필 검사와 학생들과의 수 차례에 걸친 면담을 통하여 이루어졌다. 두 그룹의 공통점은 문제풀이 과정에서 높은 성취도를 보인 학생이라도 함수의 정의, 다양한 표현방법 및 관계 등의 개념적인 인지도에서는 정확하게 이해하지 못한다는 것이고, 서로 다른점은 어려운 문제 풀이 과정에서 한국학생들이 미국학생보다 자신감과 지구력을 갖고 적극성을 보이고 있다는 것이다. 이는 학생 개인이 갖고 있는 강력한 의지와 두 나라 사이의 다른 교육체제와 교육환경에 기인함을 지적하고자 한다.

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