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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.
1

Adaptation for Assembly Part Design Based on Assemblability and Manufacturability

Chang, Guanghsu, Su, Cheng Chung, Priest, John W. 01 December 2006 (has links)
Case-Based Reasoning (CBR) has been successfully applied to many fields especially in the design domain. Poor assembly part design increases the cost, raises the manufacturing complexity and reduces the product quality. However, little research has been devoted to predict the potential design problems in the early design stage. The objective of this paper is to integrate the indexes of assemblability and manufacturability into adaptive phase in CBR to avoid inexperienced mistakes. Early experimental results indicate that quantitative feedback of these indexes can guide novices to depict a good assembly part design, let experienced designers confirm their experience judgments and finally impart the experience to novices through CBR methodology.
2

Automatiserade kostnadsberäkningar för plattformningsverktyg

Nordström, Philip, Mamic, Mario January 2013 (has links)
I dagsläget saknar Thor Ahlgren AB underlag för att på ett enkelt sätt kunna kalkylera och uppskatta priset för ett pressverktyg. När företaget får en förfrågan från kund angående huruvida de kan producera en detalj måste de återkomma med en offert till kunden där ett pris för verktygskostnaden är inkluderad. Innan ett pris kan offereras till kund måste Thor Ahlgren AB kontakta en verktygsmakare för prisförslag på verktyget och denna process kan variera i tid. Syftet med arbetet är att förkorta eller eliminera denna process och på så vis kunna offerera pris för konstruktion av ett pressverktyg snabbare. För att möjliggöra detta har författarna av rapporten identifierat de väsentliga parametrarna vid tillverkning av pressverktyg. För att möjliggöra identifiering av parametrarna har gruppen tagit hjälp av företagets produktionstekniker Björn Johansson och intervjuer med verktygsmakare. Gruppen utförde tre intervjuer med erfarna verktygsmakare från olika delar av landet. Genom intervju och diskussion med Thor Ahlgrens produktionstekniker Björn Johansson kunde flera verktygsparametrar identifieras som väsentliga, dvs. de konstaterades som kostnadsdrivande vid konstruktion av pressverktyg. Parametrarna var material och tjocklek på detalj som ska produceras i verktyget, antal steg i verktyg samt storlek på verktyg. Insamlandet av verktygsdata såsom pris hämtades från Thor Ahlgrens affärssystem Monitor medan data för antal steg och verktygsdimensioner hämtades genom undersökning av verktygen i företagets produktion. Informationen sammanställdes i Microsoft Excel för att användas som en databas. I framtiden kan Thor Ahlgren AB fortsätta fylla listan med fler verktyg och parametrar. Sedan kan listan med fördel användas som en databas i en beräkningsmodell eller i ett speciellt konstruerat datorprogram för prisuppskattning av pressverktyg. Ett datorprogram har utvecklats av gruppens handledare Joel Johansson för ändamålet. Easy CBR är ett lättanvänt verktyg som ska fungera som en plattform för automatisering av enklare konstruktionsprocesser. Programmet har en koppling till Excel så att tabeller, som den aktuella verktygslistan, kan föras in och analyseras i systemet. Funktionen möjliggör att sökningar kan utföras så att ny verktygsdata jämförs med data för äldre verktyg. Detta utgör teorin för Case-based Reasoning som bygger på att jämföra nya problem med äldre, redan lösta problem. Teorin appliceras på verktygslistan med hjälp av programmet Easy CBR. Programmet kan finna liknande verktyg vilket kan ge uppskattning om vad inköpspriset på det nya verktyget kan komma att vara. Författarna av rapporten anser att det finns potential inom området och att projektet samt datorverktyget har goda utvecklingsmöjligheter om arbetet fortskrids. / The current situation is that Thor Ahlgren AB lacks in the basis of a simple tool to calculate and estimate the price for tools used for sheet metal forming. The company receives an inquiry from a customer regarding if they can produce a product. Further on they must present a price for the customer where the tooling cost is included. Before a price can be presented to the customer Thor AhlgrenAB needs to contact several toolmakers for the price of the tool and this process can vary in time. The goal of this work is to reduce or eliminate the time for this process and then be able to offer a price for the tool to the customer faster. To do this the authors of the report had to identify the essential parameters in the manufacturing of pressing tools. In order to identify the essential parameters the group had help from the production technician Björn Johansson at Thor Ahlgren AB and several interviews with toolmakers. The group conducted three interviews with experienced toolmakers from different parts of the country. The interviews were spread out over the project time to make it possible to discuss ideas and theories that arose during the collection of tool data and literature review. From discussion with Björn Johansson at Thor Ahlgren AB the group was able to identify several tool parameters as essential, i.e. they were founded as cost drivers for the design in manufacturing of pressing tools. These parameters were identified as the material and thickness of the product that will be produced by the tool, the number of steps in the tool and the size of the tool. Tool prices was found in Thor Ahlgren’s Enterprise resource planning system called Monitor while data concerning the number of steps and tool dimensions that were retrieved from examination of the tools in the company’s production site. This information was assembled in the program Microsoft Excel as a database. In the future the company will be able to continue to fill the list with more tools and parameters. The list will be used as a database in a calculation model or specially designed computer software for estimating price for manufacture of tools. A computer software has been developed by the group instructor Joel Johansson to be used in this purpose. Easy CBR is an easy tool to use that will serve as a platform for the automation of simple construction processes. The software has a link to Microsoft Excel to make it possible to retrieve data from the database and analyze it using the tool. New tool data will be compared with the old data of the tools and the best match will be presented. This follows the theory of Case-based Reasoning that’s based on comparing new cases with old, already solved cases or problems. This theory is applied to the database with help of Easy CBR. In this way similar tools can give the engineer an estimated price for the new tool. The authors of this report believes that there is potential in this area of work and if the work continues it is possible to develop a software that will be useful for Thor Ahlgren AB.
3

Case-Based Representation of Assembly Part Design Expertise

Chang, Guanghsu, Su, Cheng Chung, Priest, John W. 01 December 2006 (has links)
Concrete design rules can facilitate the designer to depict capable design and reliable products. However, it is difficult to deduce systematic design rules from previous experience and to modify the rules in a rule-based system. In the last decade, Case-Based Reasoning (CBR) has become an important methodology to solve the problem. The objective of this paper is to determine the appropriate case representation used in assembly part design for developing a CBR system. The designer can obtain real-time Early experimental results indicate that the case representation can appropriately represent the expertise and experience of assembly part design based on CBR methodology.
4

Improving the time frame reduction for reuse of roof rack components in cars using Case-based reasoning

Harish Acharya, Maniyoor, Sudsawat, Suppatarachai January 2012 (has links)
Now a days where technological advancements are growing at a rapid pace, it has become a common norm for all the manufacturing companies to be abreast with these advancements for being competitive in market. This thesis deals with development of one such common norm for one of the products (Roof rack component) for company Thule. The main aim of the thesis is to curtail the products lead time to market and this was achieved by using an artificial intelligence technique i.e., Case-based reasoning (CBR). Roof rack component which is mounted on car roof is mainly constituted by two parts foot pad and bracket, this thesis main interest was concerned with only brackets and its geometry. This thesis is based on contemplating the already implemented concepts in this context, designer requirements and exploring better solutions. The methods of implementation adopted here was using CBR concept which is based on indexing , retrieve, adapt, review, retain and employing these concepts in form of an algorithm. The concept for developing the algorithm was based on Iterative closest point (ICP) approach which emphasise on assigning lower weight to pairs with greater point to point distance. The results portrayed are with respect to geometry and also with respect to application interface developed, which both together provides us a better solution.
5

Lessons Learned from Designing a Comprehensive Case-Based Reasoning (CBR) Tool for Support of Complex Thinking

Richmond, Doug 25 May 2007 (has links)
This research study focused on learning lessons from the experience of designing a comprehensive case-based reasoning (CBR) tool for support of complex thinking skills. Theorists have historically identified, analyzed, and classified different thinking processes and skills. Thinking skills have been increasingly emphasized in national standards, state testing, curricula, teaching and learning resources, and research agendas. Complex thinking is the core of higher-order thinking. Complex thinking is engaged when different types of thinking and action converge to resolve a real-world, ill-structured issue such as solving a problem, designing an artifact, or making a decision. By integrating reasoning, memory, and learning in a model of cognition for learning from concrete problem-solving experience, CBR can be used to engage complex thinking. In similar and different ways, CBR theory and the related theories of constructivism and constructionism promote learning from concrete, ill-structured problem-solving experience. Seven factors or characteristics, and by extension, design requirements, that should be incorporated in a comprehensive CBR tool were extracted from theory. These requirements were consistent with five theory-, research-based facilitators of learning from concrete experience. Subsequent application of the Dick, Carey, and Carey model to these design requirements generated twenty-nine specifications for design of the tool. This research study was carried out using developmental research methodology and a standard development model. The design process included front-end analysis, creating a prototype of the tool, and evaluating the prototype. / Ph. D.
6

Élaboration d'ontologies médicales pour une approche multi-agents d'aide à la décision clinique / A multi-agent framework for the development of medical ontologies in clinical decision making

Shen, Ying 20 March 2015 (has links)
La combinaison du traitement sémantique des connaissances (Semantic Processing of Knowledge) et de la modélisation des étapes de raisonnement (Modeling Steps of Reasoning), utilisés dans le domaine clinique, offrent des possibilités intéressantes, nécessaires aussi, pour l’élaboration des ontologies médicales, utiles à l'exercice de cette profession. Dans ce cadre, l'interrogation de banques de données médicales multiples, comme MEDLINE, PubMed… constitue un outil précieux mais insuffisant car elle ne permet pas d'acquérir des connaissances facilement utilisables lors d’une démarche clinique. En effet, l'abondance de citations inappropriées constitue du bruit et requiert un tri fastidieux, incompatible avec une pratique efficace de la médecine.Dans un processus itératif, l'objectif est de construire, de façon aussi automatisée possible, des bases de connaissances médicales réutilisables, fondées sur des ontologies et, dans cette thèse, nous développons une série d'outils d'acquisition de connaissances qui combinent des opérateurs d'analyse linguistique et de modélisation de la clinique, fondés sur une typologie des connaissances mises en œuvre, et sur une implémentation des différents modes de raisonnement employés. La connaissance ne se résume pas à des informations issues de bases de données ; elle s’organise grâce à des opérateurs cognitifs de raisonnement qui permettent de la rendre opérationnelle dans le contexte intéressant le praticien.Un système multi-agents d’aide à la décision clinique (SMAAD) permettra la coopération et l'intégration des différents modules entrant dans l'élaboration d'une ontologie médicale et les sources de données sont les banques médicales, comme MEDLINE, et des citations extraites par PubMed ; les concepts et le vocabulaire proviennent de l'Unified Medical Language System (UMLS).Concernant le champ des bases de connaissances produites, la recherche concerne l'ensemble de la démarche clinique : le diagnostic, le pronostic, le traitement, le suivi thérapeutique de différentes pathologies, dans un domaine médical donné.Différentes approches et travaux sont recensés, dans l’état de question, et divers paradigmes sont explorés : 1) l'Evidence Base Medicine (une médecine fondée sur des indices). Un indice peut se définir comme un signe lié à son mode de mise en œuvre ; 2) Le raisonnement à partir de cas (RàPC) se fonde sur l'analogie de situations cliniques déjà rencontrées ; 3) Différentes approches sémantiques permettent d'implémenter les ontologies.Sur l’ensemble, nous avons travaillé les aspects logiques liés aux opérateurs cognitifs de raisonnement utilisés et nous avons organisé la coopération et l'intégration des connaissances exploitées durant les différentes étapes du processus clinique (diagnostic, pronostic, traitement, suivi thérapeutique). Cette intégration s’appuie sur un SMAAD : système multi-agent d'aide à la décision. / The combination of semantic processing of knowledge and modelling steps of reasoning employed in the clinical field offers exciting and necessary opportunities to develop ontologies relevant to the practice of medicine. In this context, multiple medical databases such as MEDLINE, PubMed are valuable tools but not sufficient because they cannot acquire the usable knowledge easily in a clinical approach. Indeed, abundance of inappropriate quotations constitutes the noise and requires a tedious sort incompatible with the practice of medicine.In an iterative process, the objective is to build an approach as automated as possible, the reusable medical knowledge bases is founded on an ontology of the concerned fields. In this thesis, the author will develop a series of tools for knowledge acquisition combining the linguistic analysis operators and clinical modelling based on the implemented knowledge typology and an implementation of different forms of employed reasoning. Knowledge is not limited to the information from data, but also and especially on the cognitive operators of reasoning for making them operational in the context relevant to the practitioner.A multi-agent system enables the integration and cooperation of the various modules used in the development of a medical ontology.The data sources are from medical databases such as MEDLINE, the citations retrieved by PubMed, and the concepts and vocabulary from the Unified Medical Language System (UMLS).Regarding the scope of produced knowledge bases, the research concerns the entire clinical process: diagnosis, prognosis, treatment, and therapeutic monitoring of various diseases in a given medical field.It is essential to identify the different approaches and the works already done.Different paradigms will be explored: 1) Evidence Based Medicine. An index can be defined as a sign related to its mode of implementation; 2) Case-based reasoning, which based on the analogy of clinical situations already encountered; 3) The different semantic approaches which are used to implement ontologies.On the whole, we worked on logical aspects related to cognitive operators of used reasoning, and we organized the cooperation and integration of exploited knowledge during the various stages of the clinical process (diagnosis, prognosis, treatment, therapeutic monitoring). This integration is based on a SMAAD: multi-agent system for decision support.
7

Methode zum Einsatz von Web 2.0-Werkzeugen in der Fabrikplanung

Clauß, Michael 08 May 2013 (has links)
Dem Web 2.0 werden - nicht selten mit euphorischem Unterton - hinsichtlich Interaktion, Selbstorganisation und Nutzbarmachung kollektiver Intelligenz enorme Nutzenpotentiale nachgesagt. Ansätze mit Bezug zum Unternehmenskontext werden unter dem Stichwort Enterprise 2.0 behandelt und beschäftigen sich vorrangig mit der Unterstützung des betrieblichen Wissensmanagements. Speziell für die zunehmend durch Komplexität sowie intensive Interaktionsprozesse geprägte Fabrikplanung lassen sich durch einen zielgerichteten Einsatz von Web 2.0-Werkzeugen positive Effekte erwarten. Zielstellung dieser Arbeit ist die Entwicklung einer Methode zum Einsatz von Web 2.0-Werkzeugen in der Fabrikplanung. Hierfür erfolgt zunächst eine Bestandsaufnahme relevanter Ansätze und Begriffe in diesen Bereichen. Anschließend wird auf Grundlage system-, handlungs- und tätigkeitstheoretischer Überlegungen ein situativer Forschungsansatz begründet. Die Methodenentwicklung erfolgt als problemspezifische Ausgestaltung des Fall-basierten Schließens. Sie ist in ein entsprechend angepasstes Vorgehen der morphologisch-typologischen Theorieentwicklung eingebettet und basiert auf einer umfassenden Analyse hierfür relevanter Theorien, Modelle und Ansätze. Die Methode beruht auf einer kontinuierlichen Erfassung und Wiederverwendung von Erfahrungswissen. Sie wird abschließend evaluiert, wobei u.a. ein Prototyp entwickelt wird, der den praktischen Einsatz der entwickelten Methode unterstützt.:Abbildungsverzeichnis Tabellenverzeichnis Anlagenverzeichnis Symbol- und Abkürzungsverzeichnis 1 Einleitung 1.1 Motivation 1.2 Problemstellung 1.3 Zielstellung 1.4 Aufbau der Arbeit 2 Grundlagen 2.1 Phänomen Web 2.0 2.2 Fabrikplanung 3 Forschungsansatz 3.1 Betrachtungsrahmen 3.2 Bearbeitungsmethodik 4 Methodenentwicklung 4.1 Systemmodell 4.2 Morphologische Fallbasis 4.3 Bewertungssystematik 4.4 Gesamtmethode 5 Evaluation 5.1 Ansätze und Methoden 5.2 Methodenauswahl 5.3 Durchführung 5.4 Gesamtbewertung 6 Schlussbetrachtung 6.1 Zusammenfassung 6.2 Ausblick Literaturverzeichnis Anlagen / The Web 2.0 is supposed to have huge potential for the support of interaction, selforganization and the utilization of collective intelligence. Approaches related to an enterprise context are discussed with the keyword Enterprise 2.0 and mainly deal with potentials to support the operational knowledge management. A systematic approach for the use of web-based collaborative tools is expected to generate positive effects on modern factory planning, which faces increasing complexity and dynamic interactions. The objective of this work is to develop a methodical approach for the use of web-based collaborative tools in factory planning. Therefore, in the first part of this thesis an overview of relevant approaches and terms in the areas of Web 2.0 and factory planning is being worked out. In a second step, a situational approach is identified as an appropriate view after due consideration and contextual discussion of system, action and activity theory. The development of the methodical approach is based on a problem-specific adaptation of case-based reasoning. It is embedded into an elaborated procedure of morphologic-typological theory building and bases on a comprehensive analysis of relevant theories, models and approaches. The evolved method relies on continuous collection and reutilisation of experiential knowledge. It is evaluated through different methods, inter alia by the construction of a prototype that supports its practical use.:Abbildungsverzeichnis Tabellenverzeichnis Anlagenverzeichnis Symbol- und Abkürzungsverzeichnis 1 Einleitung 1.1 Motivation 1.2 Problemstellung 1.3 Zielstellung 1.4 Aufbau der Arbeit 2 Grundlagen 2.1 Phänomen Web 2.0 2.2 Fabrikplanung 3 Forschungsansatz 3.1 Betrachtungsrahmen 3.2 Bearbeitungsmethodik 4 Methodenentwicklung 4.1 Systemmodell 4.2 Morphologische Fallbasis 4.3 Bewertungssystematik 4.4 Gesamtmethode 5 Evaluation 5.1 Ansätze und Methoden 5.2 Methodenauswahl 5.3 Durchführung 5.4 Gesamtbewertung 6 Schlussbetrachtung 6.1 Zusammenfassung 6.2 Ausblick Literaturverzeichnis Anlagen

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