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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Možnosti využití neurčité logiky v oceňovací praxi / Fuzzy Logic in Price Assessment in Real Estate Business

Závěrka, Pavel January 2010 (has links)
Abstract The following thesis discusses the problems of apprising methods of real estate with regard to subjective factor which is inherited in the process by the appricing subject. It discusses methods, evaluations and points out possible disturbing effects and faults which could influence these methods. The example case study shows possibilities in using the power of fuzzy logic, which contributes in a significant way to higher transparency, reproducibility and portability of the whole appricing process. The main goal of the thesis is to introduce the advantages and power of a new evaluation method in the appricing process.
42

Vyhodnocení investic s využitím fuzzy logiky / Evaluation of Investment with the Usage of Fuzzy Logic

Vaňková, Jana January 2016 (has links)
The thesis deals with the evaluation of investments in intangible fixed assets. The company VIKI, spol. s.r.o. is interested in a new storage space acquisition, and therefore the main objective is to choose the best offer by using fuzzy logic. Evaluation is done in Excel, particularly in the Visual Basic environment and in MATLAB. The output of the thesis is an easy to use form that can be reused for other possible offers.
43

Fuzzy-Set Veränderungsanalyse für hochauflösende Fernerkundungsdaten

Tufte, Lars 07 April 2006 (has links)
Die Fernerkundung ist eine wichtige Quelle für aktuelle und qualitativ hochwertige Geodaten bzw. für die Aktualisierung von vorhandenen Geodaten. Die Entwicklung von neuen flugzeug- und satellitengestützten digitalen Sensoren in den letzten Jahren hat diese Bedeutung noch erhöht. Die Sensoren erschließen aufgrund ihrer verbesserten räumlichen und radiometrischen Auflösung und der vollständig digitalen Verarbeitungskette neue Anwendungsfelder. Klassische Auswerteverfahren stoßen bei der Analyse der Daten häufig an ihre Grenzen. Die in dieser Arbeit vorgestellte multiskalige objektklassen-spezifische Analyse stellt hier ein sehr gut geeignetes Verfahren dar, welches gute Ergebnisse liefert. Die Klassifizierung der Daten erfolgt mittels eines Fuzzy- Klassifizierungsverfahrens, welches Vorteile in der Genauigkeit und Interpretierbarkeit der Ergebnisse liefert. Die thematische Genauigkeit (Datenqualität) der Fuzzy-Klassifizierung ist von entscheidender Bedeutung für die Akzeptanz der Ergebnisse und ihre weitere Nutzung. Hier wurden Methoden zur räumlich differenzierten Ermittlung und Visualisierung der thematischen Genauigkeit entwickelt.Außerdem wurde die Methode der segmentbasierten Fuzzy-Logic Veränderungsanalyse (SFLV) entwickelt. Die Methode ermöglicht die Veränderungsanalyse von sehr bis ultra hoch aufgelösten Fernerkundungsdaten mit einer differenzierten Aussage zu den eingetretenen Veränderungen. Sie basiert auf den Standard Operationen für unscharfe Mengen und nutzt die Ergebnisse der entwickelten Methode zur Analyse hochauflösender Fernerkundungsdaten. Die SFLV liefert einen deutlichen Mehrwert zu dem klassischen Vergleich zweier Klassifizierungsergebnisse, indem sich differenzierte Aussagen über mögliche Veränderungen machen lassen. Die Anwendbarkeit der SFLV wurde erfolgreich an einem kleinen Untersuchungsgebiet auf der Elbinsel Pagensand beispielhaft für Veränderungsanalyse von Biotoptypen auf der Grundlage von HRSC-A Daten aufgezeigt.
44

Eliminating Redundant and Less-informative RSS News Articles Based on Word Similarity and A Fuzzy Equivalence Relation

Garcia, Ian 10 January 2007 (has links) (PDF)
The Internet has marked this era as the information age. There is no precedent in the amazing amount of information, especially network news, that can be accessed by Internet users these days. As a result, the problem of seeking information in online news articles is not the lack of them but being overwhelmed by them. This brings huge challenges regarding processing of online news feeds, i.e., how to determine which news article is important, how to determine the quality of each news article, and how to filter irrelevant and redundant information. In this thesis, we propose a method for filtering redundant and less-informative RSS news articles that solves the problem of excessive number of news feeds observed in RSS news aggregators. Our filtering approach measures similarity among RSS news entries by using the Fuzzy-Set Information Retrieval model and a fuzzy equivalent relation for computing word/sentence similarity to detect redundant and less-informative news articles.
45

The Creation Of Tools And Models To Characterize And Quantify User-centered Design Considerations In Product And System Developm

Meza, Katherine 01 January 2008 (has links)
Ease of use differentiates products in a highly competitive market place. It also brings an added value that culminates in a higher degree of customer satisfaction, repeated business, increased sales, and higher revenue. User-centered design is a strategic asset that companies can use to improve their customer relationships by learning more about their customers, and increase their sales. In today's economy, the measurement of intangible assets such as user experience has become a major need for industries because of the relationship between user-centered design and organizational benefits such as customer loyalty. As companies realize that the inclusion of user-centered design concepts in product or system design are a key component of attracting and maintaining customers, as well as increasing revenue, the need for quantitative methods to describe these benefits has become more urgent. The goal of this research is to develop a methodology to characterize user-centered design features, customer benefits and organizational benefits resulting from developing products using user-centered design principles through the use of an integrated framework of critical factors. Therefore, this research focuses on the identification of the most significant variables required to assess and measure the degree of user-centered design (UCD) characteristics included in the various aspects of product development such as physical design features, cognitive design attributes, industrial design aspects and user experience design considerations. Also this research focuses on the development of assessment tools for developers to use when evaluating the incorporation of user-centered design features in the creation of products and systems. In addition, a mathematical model to quantify the inclusion of UCD factors considered in the design of a product and systems is presented in this research. The results obtained using the assessment tools and the mathematical model can be employed to assess the customer benefits and organizational benefits resulting from including user-centered design features in the creation of products and systems. Overall, organizational benefits such as customer loyalty, company image, and profitability are expected to be impacted by the company's capability to meet or exceed stated design claims and performance consistency while maintaining aesthetic appeal, long product life, and product usefulness. The successful completion of this research has produced many beneficial research findings. For example, it has helped characterize and develop descriptors for estimating critical quantitative and qualitative components, sub-components, and factors influencing user-centered design that are related to customer and organizational benefits through the use of fuzzy set modeling. In addition, the development of specific tools, methods, and techniques for evaluating and quantifying UCD components resulted from this study.
46

A Systematic Analysis To Identify, Mitigate, Quantify, And Measure Risk Factors Contributing To Falls In Nasa Ground Support Ope

Ware, Joylene 01 January 2009 (has links)
The objective of the research was to develop and validate a multifaceted model such as a fuzzy Analytical Hierarchy Process (AHP) model that considers both qualitative and quantitative elements with relative significance in assessing the likelihood of falls and aid in the design of NASA Ground Support Operations in aerospace environments. The model represented linguistic variables that quantified significant risk factor levels. Multiple risk factors that contribute to falls in NASA Ground Support Operations are task related, human/personal, environmental, and organizational. Six subject matter experts were asked to participate in a voting system involving a survey where they judge risk factors using the fundamental pairwise comparison scale. The results were analyzed and synthesize using Expert Choice Software, which produced the relative weights for the risk factors. The following are relative weights for these risk factors: Task Related (0.314), Human/Personal (0.307), Environmental (0.248), and Organizational (0.130). The overall inconsistency ratio for all risk factors was 0.07, which indicates the model results were acceptable. The results show that task related risk factors are the highest cause for falls and the organizational risk are the lowest cause for falls in NASA Ground Support Operations. The multiple risk factors weights were validated by having two teams of subject matter experts create priority vectors separately and confirm the weights are valid. The fuzzy AHP model usability was utilizing fifteen subjects in a repeated measures analysis. The subjects were asked to evaluate three scenarios in NASA KSC Ground Support Operations regarding various case studies and historical data. The three scenarios were Shuttle Landing Facility (SLF), Launch Complex Payloads (LCP), and Vehicle Assembly Building (VAB). The Kendall Coefficient of Concordance for assessment agreement between and within the subjects was 1.00. Therefore, the appraisers are applying essentially the same standard when evaluating the scenarios. In addition, a NASA subject matter expert was requested to evaluate the three scenarios also. The predicted value was compared to accepted value. The results from the subject matter expert for the model usability confirmed that the predicted value and accepted value for the likelihood rating were similar. The percentage error for the three scenarios was 0%, 33%, 0% respectively. Multiple descriptive statistics for a 95% confidence interval and t-test are the following: coefficient of variation (21.36), variance (0.251), mean (2.34), and standard deviation (0.501). Model validation was the guarantee of agreement with the NASA standard. Model validation process was partitioned into three components: reliability, objectivity, and consistency. The model was validated by comparing the fuzzy AHP model to NASA accepted model. The results indicate there was minimal variability with fuzzy AHP modeling. As a result, the fuzzy AHP model is confirmed valid. Future research includes developing fall protection guidelines.
47

Fuzzy evidence theory and Bayesian networks for process systems risk analysis

Yazdi, M., Kabir, Sohag 21 October 2019 (has links)
Yes / Quantitative risk assessment (QRA) approaches systematically evaluate the likelihood, impacts, and risk of adverse events. QRA using fault tree analysis (FTA) is based on the assumptions that failure events have crisp probabilities and they are statistically independent. The crisp probabilities of the events are often absent, which leads to data uncertainty. However, the independence assumption leads to model uncertainty. Experts’ knowledge can be utilized to obtain unknown failure data; however, this process itself is subject to different issues such as imprecision, incompleteness, and lack of consensus. For this reason, to minimize the overall uncertainty in QRA, in addition to addressing the uncertainties in the knowledge, it is equally important to combine the opinions of multiple experts and update prior beliefs based on new evidence. In this article, a novel methodology is proposed for QRA by combining fuzzy set theory and evidence theory with Bayesian networks to describe the uncertainties, aggregate experts’ opinions, and update prior probabilities when new evidences become available. Additionally, sensitivity analysis is performed to identify the most critical events in the FTA. The effectiveness of the proposed approach has been demonstrated via application to a practical system. / The research of Sohag Kabir was partly funded by the DEIS project (Grant Agreement 732242).
48

A fuzzy data-driven reliability analysis for risk assessment and decision making using Temporal Fault Trees

Kabir, Sohag 30 August 2023 (has links)
Yes / Fuzzy data-driven reliability analysis has been used in different safety-critical domains for risk assessment and decision-making where precise failure data is non-existent. Expert judgements and fuzzy set theory have been combined with different variants of fault trees as part of fuzzy data-driven reliability analysis studies. In such fuzzy fault tree analyses, different people represented failure data using different membership functions for the fuzzy set, and different parameters were set differently in the expert opinion elicitation process. Due to the availability of a wide variety of options, it is possible to obtain different outcomes when choosing one option over another. This article performed an analysis in the context of fuzzy data-based temporal fault tree analysis to investigate the effect of choosing different membership functions on the estimated system reliability and criticality ranking of different failure events. Moreover, the effect of using different values for the relaxation factor, a parameter set during the expert elicitation process, was studied on the system reliability and criticality evaluation. The experiments on the fuel distribution system case study show system reliability did not vary when triangular and trapezoidal fuzzy numbers were used with the same upper and lower bounds. However, it was seen that the criticality rankings of a couple of events were changed due to choosing different membership functions and different values of relaxation factor
49

Uncertainty handling in fault tree based risk assessment: State of the art and future perspectives

Yazdi, M., Kabir, Sohag, Walker, M. 18 October 2019 (has links)
Yes / Risk assessment methods have been widely used in various industries, and they play a significant role in improving the safety performance of systems. However, the outcomes of risk assessment approaches are subject to uncertainty and ambiguity due to the complexity and variability of system behaviour, scarcity of quantitative data about different system parameters, and human involvement in the analysis, operation, and decision-making processes. The implications for improving system safety are slowly being recognised; however, research on uncertainty handling during both qualitative and quantitative risk assessment procedures is a growing field. This paper presents a review of the state of the art in this field, focusing on uncertainty handling in fault tree analysis (FTA) based risk assessment. Theoretical contributions, aleatory uncertainty, epistemic uncertainty, and integration of both epistemic and aleatory uncertainty handling in the scientific and technical literature are carefully reviewed. The emphasis is on highlighting how assessors can handle uncertainty based on the available evidence as an input to FTA.
50

Uncertainty handling in fault tree based risk assessment: State of the art and future perspectives

Mohammad, Y., Kabir, Sohag, Martin, W. 18 October 2019 (has links)
Yes / Risk assessment methods have been widely used in various industries, and they play a significant role in improving the safety performance of systems. However, the outcomes of risk assessment approaches are subject to uncertainty and ambiguity due to the complexity and variability of system behaviour, scarcity of quantitative data about different system parameters, and human involvement in the analysis, operation, and decision-making processes. The implications for improving system safety are slowly being recognised; however, research on uncertainty handling during both qualitative and quantitative risk assessment procedures is a growing field. This paper presents a review of the state of the art in this field, focusing on uncertainty handling in fault tree analysis (FTA) based risk assessment. Theoretical contributions, aleatory uncertainty, epistemic uncertainty, and integration of both epistemic and aleatory uncertainty handling in the scientific and technical literature are carefully reviewed. The emphasis is on highlighting how assessors can handle uncertainty based on the available evidence as an input to FTA.

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