• Title/Summary/Keyword: Evidence theory

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Dempster-Shafer's Evidence Theory-based Edge Detection

  • Seo, Suk-Tae;Sivakumar, Krishnamoorthy;Kwon, Soon-Hak
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.11 no.1
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    • pp.19-24
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    • 2011
  • Edges represent significant boundary information between objects or classes. Various methods, which are based on differential operation, such as Sobel, Prewitt, Roberts, Canny, and etc. have been proposed and widely used. The methods are based on a linear convolution of mask with pre-assigned coefficients. In this paper, we propose an edge detection method based on Dempster-Shafer's evidence theory to evaluate edgeness of the given pixel. The effectiveness of the proposed method is shown through experimental results on several test images and compared with conventional methods.

Comparison among Methods of Modeling Epistemic Uncertainty in Reliability Estimation (신뢰성 해석을 위한 인식론적 불확실성 모델링 방법 비교)

  • Yoo, Min Young;Kim, Nam Ho;Choi, Joo Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.6
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    • pp.605-613
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    • 2014
  • Epistemic uncertainty, the lack of knowledge, is often more important than aleatory uncertainty, variability, in estimating reliability of a system. While the probability theory is widely used for modeling aleatory uncertainty, there is no dominant approach to model epistemic uncertainty. Different approaches have been developed to handle epistemic uncertainties using various theories, such as probability theory, fuzzy sets, evidence theory and possibility theory. However, since these methods are developed from different statistics theories, it is difficult to interpret the result from one method to the other. The goal of this paper is to compare different methods in handling epistemic uncertainty in the view point of calculating the probability of failure. In particular, four different methods are compared; the probability method, the combined distribution method, interval analysis method, and the evidence theory. Characteristics of individual methods are compared in the view point of reliability analysis.

A Study on the Processes of Elaborating Hypotheses in Abductive Inquiry of Preservice Elementary School Teachers (예비 초등 교사들의 귀추적 탐구 활동에서 가설의 정교화 과정에 관한 연구)

  • Oh, Phil-Seok;Oh, Sung-Jin
    • Journal of The Korean Association For Science Education
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    • v.31 no.1
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    • pp.128-142
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    • 2011
  • The goal of this study was to investigate how hypotheses were elaborated after their initial appearances in the context of scientific problem solving. Data were collected from a class in which preservice elementary school teachers in groups carried out abductive inquiry of earth science. The analysis revealed two major processes of hypothesis elaboration: theory-driven and evidence-driven. The theory-driven process was in turn distinguished into two kinds of subprocesses: one is in pursuit of internal coherence and the other external coherence. The evidencedriven elaboration also had two subprocesses, which were triggered by direct evidence and indirect or analogical evidence, respectively. In addition, hypotheses were more often than not modified by a wrong theory or evidence whether it was driven by a theory or evidence. Implications for science education and related research were discussed.

An Evidence Retraction Scheme on Evidence Dependency Network

  • Lee, Gye Sung
    • International journal of advanced smart convergence
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    • v.8 no.1
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    • pp.133-140
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    • 2019
  • In this paper, we present an algorithm for adjusting degree of belief for consistency on the evidence dependency network where various sets of evidence support different sets of hypotheses. It is common for experts to assign higher degree of belief to a hypothesis when there is more evidence over the hypothesis. Human expert without knowledge of uncertainty handling may not be able to cope with how evidence is combined to produce the anticipated belief value. Belief in a hypothesis changes as a series of evidence is known to be true. In non-monotonic reasoning environments, the belief retraction method is needed to clearly deal with uncertain situations. We create evidence dependency network from rules and apply the evidence retraction algorithm to refine belief values on the hypothesis set. We also introduce negative belief values to reflect the reverse effect of evidence combination.

Middle School Gifted Students' Evidence-Based Reasoning about the Shape of a Planet's Orbit (행성 궤도의 모양에 관한 중학교 영재 학생들의 증거 기반 추론)

  • Oh, Phil Seok
    • Journal of the Korean earth science society
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    • v.42 no.1
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    • pp.118-131
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    • 2021
  • The purpose of this study was to investigate the characteristics of evidence-based reasoning practiced by middle school gifted students. Data were collected through an online task in which middle school students in gifted education institutes of a university located in the metropolitan area, Korea, performed inquiry about the shape of a planet's orbit. The students were given data of Mercury's greatest elongations and asked to draw the planet's orbit with the data. Each of the students was also asked to provide his or her hypothesis of Mercury's orbit before the drawing and to reason about the orbit again using his or her own drawing as evidence. The content analysis of the students' reports revealed 5 different types of judgement about the shape of Mercury's orbit, 4 types of reasoning about the hypothesis and evidence, and the characteristics of evidence-based reasoning within the judgement types. Based upon the analysis results, the importance of proper interpretations of evidence in evidence-based reasoning, the core role of the theory-evidence coordination, and the usefulness of working with multiple hypotheses were discussed. In addition, implications for earth science education were suggested.

An Improved Dempster-Shafer Algorithm Using a Partial Conflict Measurement

  • Odgerel, Bayanmunkh;Lee, Chang-Hoon
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.16 no.4
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    • pp.308-317
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    • 2016
  • Multiple evidences based decision making is an important functionality for computers and robots. To combine multiple evidences, mathematical theory of evidence has been developed, and it involves the most vital part called Dempster's rule of combination. The rule is used for combining multiple evidences. However, the combined result gives a counterintuitive conclusion when highly conflicting evidences exist. In particular, when we obtain two different sources of evidence for a single hypothesis, only one of the sources may contain evidence. In this paper, we introduce a modified combination rule based on the partial conflict measurement by using an absolute difference between two evidences' basic probability numbers. The basic probability number is described in details in Section 2 "Mathematical Theory of Evidence". As a result, the proposed combination rule outperforms Dempster's rule of combination. More precisely, the modified combination rule provides a reasonable conclusion when combining highly conflicting evidences and shows similar results with Dempster's rule of combination in the case of the both sources of evidence are not conflicting. In addition, when obtained evidences contain multiple hypotheses, our proposed combination rule shows more logically acceptable results in compared with the results of Dempster's rule.

Severe Tests and Mechanisms Generating an Evidence-Hypothesis (엄격한 시험과 증거-가설 생성의 메커니즘)

  • Chun, Young-Sam
    • Korean Journal of Logic
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    • v.23 no.2
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    • pp.71-115
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    • 2020
  • It seems certain that even if the same evidence is in itself given for any hypotheses, the way how it is obtained makes some differences in its support degree of them. In this respect, it is worth paying our attention to Mayo's conception of "severe test" and her technical development of it, which are just concerned with the procedures of getting evidence. Nonetheless, there have been criticisms against her theory from various respects. Among them, here this paper focuses on those especially raised by Jung (2018) and Iseda (1999). And it attempts to defend Mayo's theory on behalf of her against their critiques. For this purpose, the paper also proposes particularly a new concept of what is called the "mechanism generating an evidence-hypothesis". On the way, Mayo's own faults are revealed as well.

Characteristics of Student Inquiry Found in Project-based Science Practices: Focusing on Theory-Evidence-Method Coordinations and Skills in Using Tools (프로젝트 기반 과학 활동 과정에서 나타나는 학생 탐구의 특징: 증거-이론-방법의 조정과 도구 사용의 솜씨를 중심으로)

  • Lee, Sun-Kyung;Han, Jiwon;Lee, Jaewon;Noh, Taehee
    • Journal of The Korean Association For Science Education
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    • v.35 no.4
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    • pp.599-608
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    • 2015
  • This study aims to explore the characteristics of student inquiry found in project-based science practices. The participants were four high school students in a science research club and worked their own project for one semester. During the project, they made their research questions, planned and executed their research procedures, and made their own conclusion. Their activities during the project were videotaped and recorded. They were also interviewed. Group worksheets and written reports were all collected for analyses. The whole processes of the inquiry were analyzed and interpreted qualitatively. The characteristics of student inquiry were presented in the view of the theory-evidence-method coordination. Three different modes of the coordinations that were found recursively in their inquiry were the theory-evidence coordination, the evidence-method coordination, and the theory-evidence-method coordination. It was also revealed that students' tacit knowledge using various tools were exhibited and these skills improved during their group works. The implications for school science inquiry education and research based on this study are discussed.

Feature Extraction and Fusion for land-Cover Discrimination with Multi-Temporal SAR Data (다중 시기 SAR 자료를 이용한 토지 피복 구분을 위한 특징 추출과 융합)

  • Park No-Wook;Lee Hoonyol;Chi Kwang-Hoon
    • Korean Journal of Remote Sensing
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    • v.21 no.2
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    • pp.145-162
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    • 2005
  • To improve the accuracy of land-cover discrimination in SAB data classification, this paper presents a methodology that includes feature extraction and fusion steps with multi-temporal SAR data. Three features including average backscattering coefficient, temporal variability and coherence are extracted from multi-temporal SAR data by considering the temporal behaviors of backscattering characteristics of SAR sensors. Dempster-Shafer theory of evidence(D-S theory) and fuzzy logic are applied to effectively integrate those features. Especially, a feature-driven heuristic approach to mass function assignment in D-S theory is applied and various fuzzy combination operators are tested in fuzzy logic fusion. As experimental results on a multi-temporal Radarsat-1 data set, the features considered in this paper could provide complementary information and thus effectively discriminated water, paddy and urban areas. However, it was difficult to discriminate forest and dry fields. From an information fusion methodological point of view, the D-S theory and fuzzy combination operators except the fuzzy Max and Algebraic Sum operators showed similar land-cover accuracy statistics.

A Proposal for Use in Research Methodology of Traditional Medicine in East Asia - Historical Evidence-Based Medicine - (전통한의학 연구방법론의 현대화에 대한 소고(小考) - 역사적 근거중심의학에 대한 제언 -)

  • Eom, Seok-Ki;Kim, Se-Hyun;Choi, Won-Cheol
    • Journal of Korean Medical classics
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    • v.23 no.2
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    • pp.89-105
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    • 2010
  • Research methodology on Traditional Medicine in East Asia refers to logical thinking system, empirical positivism system and methodology of developing these knowledge systems. Logical thinking system of abstract concepts such as analogy or abduction and positivism system of reasonable explanation such as the five elements and their characteristic theory have been used in various ways empirically or in the form of humanities and knowledge system was developed through parallel structure of empirical positivism and exegetical studies. After the 16th century, evidence was required along with the tradition of putting emphasis on rationality, logicality and empirical positivism and characteristics of medical humanities can be found in emphasizing on medical ethics. Data that can be considered as structural review paper or meta analysis from original data of research on Traditional East Asian Medicine should be evaluated as historical evidence which is equivalent to specialist opinion, descriptive disease research, single case report or case series. Historical evidence based medicine is a research method using Historical evidence to selectively support data that are faithful to traditional theory with higher possibility to be used in future traditional east Asian medicine that links between traditional knowledge and scientific research methodology. Moreover, historical evidence based medicine tries to re-evaluate the value of traditional knowledge and ultimately, guides the direction of development of traditional medicine through scientific rationality based on history and culture.