• 제목/요약/키워드: Theory of Evidence

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광학 현상 증거 해석의 인과적 추론 방식 (The Students' Causal Inference Modes on Experimental Evidence Evaluation for Optical Phenomena)

  • 박승재;장병기
    • 한국과학교육학회지
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    • 제14권2호
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    • pp.123-132
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    • 1994
  • The experimental evidence evaluation of the 11th grade students(N:91) was investigated. Specially, the influence of students' ideas about optical phenomena and presented evidence types on their evidence evaluation, and the influence of students' ideas on their causal inference modes were investigated. After eliciting the students' ideas about shadow phenomena and conformity of their idea, the experimental results with a binary outcome were presented as the evidence. Then the students were asked to evaluate the evidence. Again students' ideas were elicited. Most of students had causal ideas such that the shape of object(96%) and the inclination of screen(75%) were causes of shadow shape, not the shape(70%) and color(92%) of light source. In the case of the shape of object and the color of light source, most students(70%) believed strongly their ideas. Most responses(80%) in the evidence were evidence-based, and 12% of them were theory-based. There was no significant difference of reponses types between students with causal ideas(81%) and students with non-causal ideas(78%), between covariable and non-covariable evidence. But in the case of non-causal ideas, covariable evidence was more likely to yield evidence-based reponses than non-covariable evidence. If students had preconcepts inconsistent(84%) with the evidence, they were more likely to make evidence-based responses than the students with consistent ideas (75%) with the evidence. Especially in the case perceptually biased evidence, this tendency was marked. In the case of covariable evidence, many students made inclusion inferences(40%) rather than uncertainty inferences(32%). In the case of uncertainty inferences(94%), students more likely to make evidence-based reponses than inclusion inferences(83%) and exclusion infernces(88%). In the case of inclusion inferences and exclusion infernces, students tended to make idea-based responses and distort the evidences. In conclusion, when the students evaluate the experimental evidences, their ideas influence the causal inference modes. Especially, according to the conformity of the preconcepts and logical relation of evidences, the inference modes are more strongly depended upon the preconcepts rather than evidences.

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Fault-Tolerant Event Detection in Wireless Sensor Networks using Evidence Theory

  • Liu, Kezhong;Yang, Tian;Ma, Jie;Cheng, Zhiming
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권10호
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    • pp.3965-3982
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    • 2015
  • Event detection is one of the key issues in many wireless sensor network (WSN) applications. The uncertainties that are derived from the instability of sensor node, measurement noise and incomplete sampling would influence the performance of event detection to a large degree. Many of the present researches described the sensor readings with crisp values, which cannot adequately handle the uncertainties inhered in the imprecise sensor readings. In this paper, a fault-tolerant event detection algorithm is proposed based on Dempster-Shafer (D-S) theory (also called evidence theory). Instead of crisp values, all possible states of the event are represented by the Basic Probability Assignment (BPA) functions, with which the output of each sensor node are characterized as weighted evidences. The combination rule was subsequently applied on each sensor node to fuse the evidences gathered from the neighboring nodes to make the final decision on whether the event occurs. Simulation results show that even 20% nodes are faulty, the accuracy of the proposed algorithm is around 80% for event region detection. Moreover, 97% of the error readings have been corrected, and an improved detection capability at the boundary of the event region is gained by 75%. The proposed algorithm can enhance the detection accuracy of the event region even in high error-rate environment, which reflects good reliability and robustness. The proposed algorithm is also applicable to boundary detection as it performs well at the boundary of the event.

Krill and Currents-Physical and Biological Interactions Influencing the Distribution of Euphausia superba

  • Nicol, Stephen
    • Ocean and Polar Research
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    • 제25권4호
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    • pp.633-644
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    • 2003
  • The distribution and abundance of Antarctic krill (Euphausia superba), particularly in the South Atlantic, has traditionally been viewed as primarily determined by the flow of the Antarctic Circumpolar Current. Krill are viewed as being particles on a conveyor belt that carries them around the Antarctic continent resulting in a single circumpolar population. The evidence to support this viewpoint is largely circumstantial and there is very little direct evidence available of krill being moved by the currents-krill flux. There is also considerable biological and physical evidence which suggests that other factors may play a dominant role in the life history and distribution of krill. This review examines the evidence fur krill flux and also examines evidence that does not accord with this theory. The management implications of assuming krill flux are outlined and some lines for future research are suggested.

문항반응이론을 활용한 한의학 교육에서 본초학 시험문항에 대한 연구 (Study on the herbology test items in Korean medicine education using Item Response Theory)

  • 채한;한상윤;양기영;김형우
    • 대한본초학회지
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    • 제37권2호
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    • pp.13-21
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    • 2022
  • Objectives : The evaluation of academic achievement is pivotal for establishing accurate direction and adequate level of medical education. The purpose of this study was to firstly establish innovative item analysis technique of Item Response Theory (IRT) for analyzing multiple-choice test of herbology in the traditional Korean medicine education which has not been available for the difficulty of test theory and statistical calculation. Methods : The answers of 390 students (2012-2018) to the 14 item herbology test in college of Korean medicine were used for the item analysis. As for the multidimensional analysis of item characteristics, difficulty, discrimination, and guessing parameters along with item-total correlation and percentage of correct answer were calculated using Classical Test Theory (CTT) and IRT. Results : The validity parameters of strong and weak items were illustrated in multiple perspectives. There were 4 items with six acceptable index scores, and 5 items with only one acceptable index score. The item discrimination of IRT was found to have no significant correlation with difficulty and discrimination indices of CTT emphasizing attention of professionals of medical education as for the test credibility. Conclusion : The critical suggestions for the development, utilization and revision of test items in the e-learning and evidence-based Teaching era were made based on the results of item analysis using IRT. The current study would firstly provide foundation for upgrading the quality of Korean medicine education using test theory.

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.

The Role of Virtual Community Participation and Engagement in Building Brand Trust: Evidence from Pakistan Business Schools

  • TABISH, Muhammad;BASHIR, Muhammad Adnan;ALAM, Muhammad Mansoor;LONG, Zalizah Awang;RAHMAT, Mohd. Khairil
    • The Journal of Asian Finance, Economics and Business
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    • 제9권3호
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    • pp.399-409
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    • 2022
  • The purpose of this study is to examine the role of virtual community participation and engagement in the brand decision by building community and brand trust. In this study, two theories (Social Capital Theory and Theory of Collective Action) were tested. Both theories were linked based on existing literature, and empirical evidence was obtained through testing hypotheses. Students from five prestigious Pakistani business schools provided a total of 849 replies. The measurement model and structural model were both analyzed using the partial least square (PLS) method. The findings show that virtual community engagement and participation have a positive and significant impact on virtual community trust. Although virtual community engagement has a positive effect on brand trust, we found no evidence of a link between virtual community participation and brand trust. Later, these trusts positively influence brand choice. This study has several managerial implications. The suggested model of this study helps managers to get customers' insight, choose the right target market, and set integrated marketing communication strategies besides social media marketing strategies. The study represents a new perspective of consumer behavior that helps to understand how a customer behaves in virtual communities to trust and take the final decision to purchase.

감각처리 장애에 대한 신경생리학적 증거들 (Neurophysiological Evidence for Sensory Processing Disorder)

  • 김은영
    • 재활치료과학
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    • 제1권1호
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    • pp.5-16
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    • 2012
  • 감각통합은 이론에서 출발하여 현재 치료사들이 아동의 문제를 찾고 중재하는데 유용한 틀을 제공한다. 이전까지 대부분의 감각통합 연구들은 감각처리 장애아동들이 나타내는 행동을 측정하는 경험적 증거들을 보고하였다. 최근에 감각처리 장애 진단에 대한 객관적 증거 마련을 위해서 신경생리학적 연구 결과가 축적되기 시작하였다. 감각처리 장애에 대한 신경생리학적 근거를 찾는 연구들은 전기피부 활동, 미주신경 톤, 뇌파를 사용하여 감각처리 장애아동과 전형적으로 발달하는 또래 아동들 간 신경생리학적 반응이 다르다는 결과를 보고하였을 뿐만 아니라 감각처리 어려움과 관련한 행동 특징이 신경생리학적 지표에서도 반영됨을 발견하였다. 앞으로 연구에서는 감각통합 치료 효과를 지지하는 신경생리학적 증거도 얻을 수 있을 것이라 기대해 본다.

Application of Joint Electro-Chemical Detection for Gas Insulated Switchgear Fault Diagnosis

  • Li, Liping;Tang, Ju;Liu, Yilu
    • Journal of Electrical Engineering and Technology
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    • 제10권4호
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    • pp.1765-1772
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    • 2015
  • The integrity of the gas insulated switchgear (GIS) is vital to the safety of an entire power grid. However, there are some limitations on the techniques of detecting and diagnosing partial discharge (PD) induced by insulation defects in GIS. This paper proposes a joint electro-chemical detection method to resolve the problems of incomplete PD data source and also investigates a new unique fault diagnosis method to enhance the reliability of data processing. By employing ultra-high frequency method for online monitoring and the chemical method for detecting SF6 decomposition offline, the acquired data can form a more complete interpretation of PD signals. By utilizing DS evidence theory, the diagnostic results with tests on the four typical defects show the validity of the new fault diagnosis system. With higher accuracy and lower computation cost, the present research provides a promising way to make a more accurate decision in practical application.