Search results for " Fuzzy"

showing 10 items of 209 documents

A fully automatic approach for multimodal PET and MR image segmentation in gamma knife treatment planning

2017

The aim of this study is to combine Biological Target Volume (BTV) segmentation and Gross Target Volume (GTV) segmentation in stereotactic neurosurgery.Our goal is to enhance Clinical Target Volume (CTV) definition, including metabolic and morphologic information, for treatment planning and patient follow-up.We propose a fully automatic approach for multimodal PET and MR image segmentation. This method is based on the Random Walker (RW) and Fuzzy C-Means clustering (FCM) algorithms. A total of 19 brain metastatic tumors, undergone stereotactic neuro-radiosurgery, were retrospectively analyzed. A framework for the evaluation of multimodal PET/MRI segmentation is presented, considering volume…

Radiotherapy PlanningBrain tumorHealth Informatics02 engineering and technologyFuzzy C-means clusteringRadiosurgeryBrain tumorsMultimodal ImagingING-INF/05 - SISTEMI DI ELABORAZIONE DELLE INFORMAZIONI030218 nuclear medicine & medical imaging03 medical and health sciencesComputer-Assisted0302 clinical medicineRandom walker algorithm0202 electrical engineering electronic engineering information engineeringHumansMedicineSegmentationComputer visionRadiation treatment planningCluster analysisImage resolutionPET/MR imagingModality (human–computer interaction)Brain Neoplasmsbusiness.industryRadiotherapy Planning Computer-AssistedINF/01 - INFORMATICAMultimodal therapymedicine.diseaseRandom Walker algorithmMagnetic Resonance ImagingComputer Science ApplicationsBrain tumorGamma knife treatmentPositron-Emission Tomography020201 artificial intelligence & image processingMultimodal image segmentationBrain tumors; Fuzzy C-means clustering; Gamma knife treatments; Multimodal image segmentation; PET/MR imaging; Random Walker algorithm; Brain Neoplasms; Humans; Radiosurgery; Magnetic Resonance Imaging; Multimodal Imaging; Positron-Emission Tomography; Radiotherapy Planning Computer-AssistedArtificial intelligencebusinessGamma knife treatmentsSoftware
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Modeling risk perception in ATIS context through Fuzzy Logic

2011

Abstract This research is aimed at investigating the effect of accuracy of ATIS (Advanced Traveller Information Systems) in terms of route choices and travellers concordance to informative system. A Stated Preference Experiment has been made by using a Travel Simulator developed at the Technische Universiteit of Delft (The Netherlands). During the experiment respondents have been asked to make repeated route choices in presence of ATIS. Two kinds of information have been tested: descriptive (respondents are provided with the estimated travel times on each route), and prescriptive (respondents are provided with the estimated shortest route). For each kind of information four levels of accura…

Risk perceptionOperations researchComputer scienceConcordanceStated PreferenceContext (language use)Travellers behaviourFuzzy logicFuzzy LogicInformationStatistical analysesATISConcordanceInformation systemGeneral Materials ScienceTravel simulatorAccuracyDrivers route-choiceTravellers' behaviourBehaviorfuzzyUncertaintyPreferenceRoute choiceRisk perceptionTravel behaviorAccuracy ATIS Concordance Fuzzy Logic Risk perception Route choice Stated Preference Travel simulator Travellers' behaviour UncertaintyITSProcedia - Social and Behavioral Sciences
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Parallel Genetic Algorithms for the Tuning of a Fuzzy AQM Controller

2003

This paper presents the results of the application of a parallel Genetic Algorithm (GA) in order to design a Fuzzy Proportional Integral (FPI) controller for active queue management on Internet routers. The Active Queue Management (AQM) policies are those policies of router queue management that allow the detection of network congestion, the notification of such occurrences to the hosts on the network borders, and the adoption of a suitable control policy. Two different parallel implementations of the genetic algorithm are adopted to determine an optimal configuration of the FPI controller parameters. Finally, the results of several experiments carried out on a forty nodes cluster of workst…

RouterSettore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniQueue management systemComputer sciencebusiness.industryDistributed computingFuzzy control systemActive queue managementFuzzy logicNetwork congestionTCP Actuve Queue Management Genetic algorithms Fuzzy logic AQM TCP congestion controlControl theoryGenetic algorithmbusinessComputer network
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Approximation-based adaptive tracking control of stochastic nonlinear systems with a general form

2014

In this paper, an approximation-based adaptive tracking control scheme is proposed for a class of stochastic nonlinear systems with a more general structure. Fuzzy logical systems are used to approximate unknown nonlinearities in the controller design procedure and the backstepping technique is utilized to construct a state-feedback adaptive controller. The proposed controller can guarantee that all the signals in the closed-loop system are fourth-moment semi-globally uniformly ultimately bounded and the tracking error eventually converges to a small neighborhood around the origin. Simulation results are used to show the effectiveness of the proposed control scheme.

Scheme (programming language)business.industrystochastic nonlinear systemAdaptive fuzzy control; Backstepping; stochastic nonlinear system; Software; Artificial IntelligenceFuzzy logicAdaptive fuzzy controlTracking errorNonlinear systemSoftwareControl theoryBacksteppingArtificial IntelligenceBounded functionBacksteppingbusinesscomputerSoftwareMathematicscomputer.programming_language
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Fuzziness, Cognition and Cybernetics: a historical perspective

2015

In the present paper, we connect some old reflections about the relationships existing between the theory of fuzzy sets and cybernetics with modern, contemporary analyses of the crucial (better: unavoidable) role that fuzziness plays in the attempts at scientifically describing aspects of information sciences. The connection, which has a basic conceptual origin, has been triggered also by the recent 50th anniversary of Norbert Wiener’s death which has been instrumental in looking again at some crucial aspects of the birth of information sciences in the midst of the last century. Fuzzy sets are an essential part of this revolution and share all the innovations as well as the difficulties of …

Scientific enterprisemedicine.medical_specialtySettore INF/01 - InformaticaComputer sciencebusiness.industryPerspective (graphical)Fuzzy setCognitionSettore M-FIL/02 - Logica E Filosofia Della Scienzacybernetics fuzzy set fuzzinessMedical cyberneticsInformation scienceEpistemologymedicineCyberneticsArtificial intelligencebusinessProceedings of the 2015 Conference of the International Fuzzy Systems Association and the European Society for Fuzzy Logic and Technology
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Modellare l’incertezza nel decision making

2015

Scienze Cognitive Incertezza Logica Fuzzy
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Stable Automatic Unsupervised Segmentation of Retinal Vessels Using Self-Organizing Maps and a Modified Fuzzy C-Means Clustering

2011

In this paper an automatic unsupervised method for the segmentation of retinal vessels is proposed. Three features are extracted from the tested image. The features are scaled down by a factor of 2 and mapped into a Self-Organizing Map. A modified Fuzzy C-Means clustering algorithm is used to divide the neuron units of the map in 2 classes. The entire image is again input for the Self-Organizing Map and the class of each pixel will be the class of its best matching unit in the Self-Organizing Map. Finally, the vessel network is post-processed using a hill climbing strategy on the connected components of the segmented image. The experimental evaluation on the DRIVE database shows accurate ex…

Self-organizing mapGround truthPixelSettore INF/01 - Informaticabusiness.industryComputer scienceComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONScale-space segmentationPattern recognitionFuzzy logicComputer visionSegmentationArtificial intelligenceCluster analysisbusinessHill climbingRetinal Vessels Self-Organizing Map Fuzzy C-Means.
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An integrated fuzzy-stochastic model for revenue management: The hospitality industry case

2016

Revenue management aims at improving the performance of an organization by selling the right product/service to the right customer at the right time. This task is very dependent on uncontrollable external factors. In the hospitality industry, rooms of the hotel represent perishable assets and fixed capacities at the same time. Therefore, in the case of a stochastic process for customers calling in reservations prior to a particular booking date, a common problem for hotels is to devise a policy for maximizing the total expected profit conditional on the set of bookings. We propose a fuzzy model for the hotel revenue management under an uncertain and vague environment. Fuzziness of objectiv…

Service (business)021103 operations researchRevenue managementbusiness.industryStochastic modellingGeography Planning and DevelopmentFuzzy optimization stochastic demand revenue management booking system hospitality industry.0211 other engineering and technologies02 engineering and technologySettore SECS-P/06 - Economia ApplicataHospitality industryFuzzy logicTask (project management)Product (business)Settore SECS-S/06 -Metodi Mat. dell'Economia e d. Scienze Attuariali e Finanz.Tourism Leisure and Hospitality Management0202 electrical engineering electronic engineering information engineeringEconomicsbooking system fuzzy optimization hospitality industry revenue management stochastic demand020201 artificial intelligence & image processingOperations managementbusinessIndustrial organization
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Fuzzy ServPerf model combined with ELECTRE III to comparatively evaluate service quality of international airports in Sicily

2015

In this paper a new approach was proposed so as to comparatively evaluate the quality of service alternatives. In particular, a fuzzy extension of the ServPerf service conceptual model was considered to estimate quality scores of fundamental service criteria, whereas the non-compensative multi-criteria decision-making ELECTRE III method was employed to point out the quality ranking of service alternatives on the basis of which the comparative service quality analysis was performed. In order to show the effectiveness of the proposed approach, an empirical study concerning service quality evaluation of the three international airports in Sicily (Italy) was conducted with detailed proposals fo…

Service (business)Service qualityEngineeringOperations researchbusiness.industryStrategy and Managementmedia_common.quotation_subjectQuality of serviceTransportationManagement Monitoring Policy and LawAirport services quality Service quality benchmarking ServPerf model Multi criteria decision making (MCDM) ELECTRE method Fuzzy sets theoryEmpirical researchRankingConceptual modelQuality (business)ELECTREbusinessSettore ING-IND/16 - Tecnologie E Sistemi Di LavorazioneLawmedia_commonJournal of Air Transport Management
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DINESERV along with fuzzy hierarchical TOPSIS to support the best practices observation and service quality improvement in the restaurant context

2019

Abstract The present work proposes a new Multi-Criteria-Decision-Analysis (MCDA)-based approach integrating the DINESERV model along with the hierarchical TOPSIS method as measurement tool for evaluating quality in the restaurant services context. More in detail, on the basis of the DINESERV theoretical framework of the restaurant service quality, hierarchical TOPSIS is applied to compare quality of restaurant services. Actually, due to the prioritization process of hierarchical TOPSIS, investigated services providers are consistently and effectively assessed against criteria and sub-criteria of DINESERV, so allowing the identification of both best practices and weaknesses of delivered serv…

Service quality021103 operations researchProcess managementGeneral Computer ScienceComputer sciencemedia_common.quotation_subjectFuzzy set0211 other engineering and technologiesGeneral EngineeringContext (language use)TOPSIS02 engineering and technologyMultiple-criteria decision analysisFuzzy logicIdentification (information)0202 electrical engineering electronic engineering information engineering020201 artificial intelligence & image processingQuality (business)Restaurant service quality Multi criteria decision analysis DINESERV Hierarchical TOPSIS Fuzzy set theorySettore ING-IND/16 - Tecnologie E Sistemi Di Lavorazionemedia_common
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