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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.
31

The Development of a Hybrid Knowledge-Based System for Designing a Low Volume Automotive Manufacturing Environment. The Development of A Hybrid Knowledge-Based (KB)/Gauging Absences of Pre-Requisites (GAP)/Analytic Hierarchy Process (AHP) System for the Design and Implementation of a Low Volume Automotive Manufacturing (LVAM) Environment.

Mohamed, N.M.Z.Nik January 2012 (has links)
The product development process for the automotive industry is normally complicated, lengthy, expensive, and risky. Hence, a study on a new concept for Low Volume Automotive Manufacturing (LVAM), used for niche car models manufacturing, is proposed to overcome this issue. The development of a hybrid Knowledge Based (KB) System, which is a blend of KB System, Gauging Absences of Pre-requisites (GAP), and Analytic Hierarchy Process (AHP) is proposed for LVAM research. The hybrid KB/GAP/AHP System identifies all potential elements of LVAM issues throughout the development of this system. The KB System used in the LVAM analyses the gap between the existing and the benchmark organisations for an effective implementation. The novelty and differences in the current research approach emphasises the use of Knowledge Based (KB) System in the planning and designing stages by suggesting recommendations of LVAM implementation, through: a) developing the conceptual LVAM model; b) designing the KBLVAM System structure based on the conceptual LVAM model; and c) embedding Gauging Absences of Pre-requisites (GAP) analysis and Analytic Hierarchy Process (AHP) approach in the hybrid KBLVAM System. The KBLVAM Model explores five major perspectives in two stages. Planning Stage (Stage 1) consists of Manufacturer Environment Perspective (Level 0), LVAM Manufacturer Business Perspective (Level 1), and LVAM Manufacturer Resource Perspective (Level 2). Design Stage (Stage 2) consists of LVAM Manufacturer Capability ¿ Car Body Part Manufacturing Perspective (Level 3), LVAM Manufacturer Capability ¿ Competitive Priorities Perspective (Level 4), and LVAM Manufacturer Capability ¿ Lean Process Optimisation Perspective (Level 5). Each of these perspectives consists of modules and sub-modules that represent specific subjects in the LVAM development. Based on the conceptual LVAM model, all perspectives were transformed into the KBLVAM System structure, which is embedded with the GAP and AHP techniques, hence, key areas of potential improvement are recommended for each activity for LVAM implementation. In order to be able to address the real situation of LVAM environment, the research verification was conducted for two automotive manufacturers in Malaysia. Some published case studies were also used to check several modules for their validity and reliability. This research concludes that the developed KBLVAM System provides valuable decision making information and knowledge to assist LVAM practitioners to plan, design and implement LVAM in terms of business organisation, manufacturing aspects and practices. / Universiti Malaysia Pahang and Ministry of Higher Education Malaysia
32

The design and development of a knowledge-based lean six sigma maintenance system for sustainable buildings. The design and development of a hybrid Knowledge-based (KB)/Gauging Absence of Pre-requisites (GAP)/Analytic Hierarchy Process (AHP) model for implementing lean six sigma maintenance system in sustainable buildings' environment

Al Dairi, Jasim S.S. January 2017 (has links)
The complexity of sustainable building maintenance environment requires managers to define and implement appropriate quality benchmark system suitable for this function. Lean Six Sigma (LSS) is one of the most effective process improvement and optimization philosophy that maintenance organisations can implement in their environment. However, literature review has shown that 90% of failures in LSS implementations are due to lack of readiness to change, the unawareness of the required benchmark organisation capabilities, and improper control of priorities. The contribution of the current research approach is in developing a hybrid Knowledge-Based (KB)/GAP/AHP System, consisting of three stages (Planning, Designing and Implementation) and containing over 2500 KB rules. The KB System can assist the decision-makers in identifying the obstacles behind the organisation readiness to change into a benchmark LSS maintenance environment. Thus the KB System will be used to achieve benchmark standards by determining the gap existing between the current environment and the benchmark goal, and then suggest a detailed plan to overcome these hurdles in a prioritised and structured manner, thus achieving cost benefits. To ensure its consistency and reliability, the KB System was validated in three Oman-based maintenance organisations, and one published case study for a UK-based organisation. The results from the validation were positive with the System output suggesting list of top priorities and action plans for achieving benchmark LSS standards for these organisations. The research concludes that the developed KB System is a consistent and reliable methodology for assisting decision-makers in designing, planning, and implementing LSS for benchmark sustainable building maintenance.
33

The Development of a Hybrid Knowledge-Based System for Integrated Maintenance Strategy and Operations in an Automotive Industry Environment: The Development of a Hybrid Knowledge-Based (KB) System/ Gauging Absences of Pre-Requisites (GAP)/Analytic Hierarchy Process (AHP) Methodology for Integrated Maintenance Strategy and Operations in an Automotive Industry Environment

Milana, Milana January 2018 (has links)
The dependency of maintenance as a manufacturing logistic function has made the considerations of maintenance decisions complex in nature. The importance of maintenance has escalated significantly by the increasing of automation in manufacturing processes. This condition switches the traditional maintenance perspective of “fire-fighter” into the business competitive driver. As a consequence, maintenance needs to consider other related aspects of decision making to achieve competitive advantage. This research aims to develop a hybrid Knowledge-Based (KB) System/GAP/AHP methodology to support the integration of maintenance decision with business and manufacturing perspectives. It constructs over 2000 KB rules on Strategic Stage (business and manufacturing aspects) and Maintenance Operations Stage (maintenance aspects). Each aspect contains KB rules attached with GAP analysis to assess the gap between current and prerequisite condition. AHP analysis is then deployed to compare those aspects structurally in a pair-wise manner to identify the critical ones to be rectified. This hybrid KB system is useful in reviewing the existing maintenance system performance and provides reasonable recommendations to improve maintenance performance with respect to business and manufacturing perspectives. Eventually, it indicates the roadmap from the current state to the benchmark goals for the maintenance system. This novel methodology of KBS/GAP/AHP to support maintenance decision is developed for a particular application in the automotive environment. The validation is conducted in two automotive companies in Indonesia and one published case study in an automotive company. The result confirms that the developed KB system can provide the valid, reasonable and consistent result to propose structured recommendation for maintenance improvement priority.
34

The development of a hybrid knowledge-based system for the design of a Low Volume Automotive Manufacturing (LVAM) system

Mohamed, N.M.Z.Nik, Khan, M. Khurshid January 2012 (has links)
No / A conceptual design approach is an important stage for the development of a hybrid Knowledge-Based System (KBS) for Low Volume Automotive Manufacturing (LVAM). The development of a hybrid KBS, which is a blend of KBS and Gauging Absences of Pre-requisites (GAP), is proposed for LVAM research. The hybrid KB/GAP system identifies all potential elements of LVAM issues throughout the development of this system. The KBS used in the system design stage of the LVAM system analyses the gap between the existing and the benchmark organisations for an effective implementation through the GAP analysis technique. The proposed KBLVAM model at the design stage explores three major components, namely LVAM car body parts manufacturing perspective, LVAM competitive priorities perspective and LVAM lean environment perspective. Initial results reveal that the KBLVAM system has identified, for each perspective modules and sub-modules, the Problem Categories (PC) in a prioritised manner. / The financial support by the Malaysian Government, Universiti Malaysia Pahang and University of Bradford for this research is grateful acknowledged.
35

Beitrag zur Optimierung von Reinigungsprozessen im nicht immergierten System unter Anwendung gravitationsgetriebener Flüssigkeitsfilme

Fuchs, Enrico 26 May 2021 (has links)
Die Herstellung hochqualitativer Produkte in der Lebensmittel-, Kosmetik- und Pharmaindustrie erfordert den Einsatz reproduzierbarer Reinigungsprozesse. Häufig wird die nasschemische Reinigung als Cleaning in Place Verfahren angewandt. Diese Arbeit leistet einen Beitrag zur Optimierung von Reinigungsprozessen im nicht immergierten System insbesondere bei der Anwendung gravitationsgetriebener Flüssigkeitsfilme. Inhalte sind Untersuchungen zum Benetzungs- und Strömungsverhalten im Vergleich zur Reinigungswirkung von Flüssigkeitsfilmen. Als Modellverschmutzungen wurden zwei lebensmitteltypische Bestandteile in Kombination mit partikulären Anteilen eingesetzt. Im Ergebnis konnte nachgewiesen werden, dass sich das Reinigungsverhalten der gewählten Verschmutzungen mit der Hydrodynamik am Beispiel von Flüssigkeitsfilmen beschreiben lässt. Zusätzlich wurde ein neuartiger Ansatz zur Optimierung der Reinigungseffizienz durch die Anwendung diskontinuierlicher Flüssigkeitsfilme untersucht. Dadurch konnte gezeigt werden, dass der Ressourceneinsatz gegenüber einer kontinuierlichen Flüssigkeitsfilmströmung signifikant verringert werden kann, wobei die Reinigungszeit nur geringfügig steigt.:Danksagung ... II Inhaltsverzeichnis ... III Verzeichnis der verwendeten Formelzeichen ... VI Abkürzungsverzeichnis ... XVI 1 Einleitung, Motivation und Gegenstand der Arbeit ... 1 2 Grundlagen der Reinigung ... 3 2.1 Begriffserklärung ... 3 2.2 Industrielle Reinigungsprozesse ... 3 2.2.1 Einordnung ... 3 2.2.2 Reinigungsgeräte für die Nassreinigung im nicht immergierten System ... 8 2.3 Reinigungsvorgänge im nicht immergierten System ... 10 2.3.1 Komponenten des Reinigungssystems ... 10 2.3.2 Schmutzhaftmechanismen ... 20 2.3.3 Reinigungsmechanismen und Wirkzusammenhänge ... 23 2.3.4 Reinigungskinetik ... 28 3 Methoden für Reinigungsuntersuchungen ... 32 3.1 Einordnung ... 32 3.2 Industrielle Methoden ... 33 3.3 Wissenschaftliche Methoden ... 35 4 Gravitationsgetriebene Flüssigkeitsfilmströmungen ... 37 4.1 Einteilung von Filmströmungen und Filmkennzahlen ... 37 4.2 Kennzahlen zur Oberflächenbenetzung ... 40 4.3 Filmdicke und Filmoberflächenwelligkeit ... 47 4.3.1 Modellvorstellungen und Kennzahlen ... 47 4.3.2 Experimentelle Methoden ... 50 4.4 Strömungsgeschwindigkeit ... 54 4.4.1 Modellvorstellungen und Kennzahlen ... 54 4.4.2 Experimentelle Methoden ... 58 5 Zielsetzung und Lösungsweg ... 61 5.1 Problemstellung ... 61 5.2 Arbeitshypothese ... 62 5.3 Vorgehen ... 62 5.4 Zusammenhang mit anderen Arbeiten ... 63 6 Material und Methoden ... 64 6.1 Auswahl Substrate ... 64 6.2 Topografiebestimmung ... 64 6.3 Kontaktwinkelmessung ... 66 6.4 Untersuchungsobjekt ... 68 6.5 Grundaufbau der Versuchsanlage ... 68 6.6 Auswahl der Flüssigkeit ... 70 6.7 Festlegung der Einstellparameter für die Strömungs- und Reinigungsmessungen ... 71 6.8 Charakterisierung des Stoffsystems ... 71 6.8.1 Quellverhalten ... 71 6.8.2 Bindungskräfte ... 77 6.9 Hydrodynamik ... 79 6.9.1 Oberflächenbenetzung ... 79 6.9.2 Filmdicke ... 85 6.9.3 Strömungsgeschwindigkeit ... 102 6.10 Reinigungsuntersuchungen ... 115 6.10.1 Auswahl der Modellverschmutzungen ... 115 6.10.2 Auswahl und Konzeption der Messdatenerfassung ... 117 6.10.3 Versuchsaufbau ... 119 6.10.4 Aufnahmeparameter ... 121 6.10.5 Benetzungseinfluss auf die Phosphoreszenzintensität ... 123 6.10.6 Methode zur reproduzierbaren Verschmutzung ebener Substrate ... 125 6.10.7 Überprüfung der Reproduzierbarkeit und Gleichmäßigkeit der Verschmutzungsmethode ... 128 6.10.8 Versuchsablauf ... 130 6.10.9 Messdatenaufbereitung und -auswertung ... 130 7 Versuchsauswertung und Ergebnisse ... 140 7.1 Charakterisierung der Verschmutzung ... 140 7.1.1 Quellverhalten ... 140 7.1.2 Bindungskräfte ... 144 7.1.3 Zusammenfassung der Verschmutzungscharakterisierung ... 150 7.2 Hydrodynamik gravitationsgetriebener Flüssigkeitsfilme ... 151 7.2.1 Oberflächenbenetzung ... 151 7.2.2 Filmdicke und Filmdickenverteilung ... 163 7.2.3 Strömungsgeschwindigkeit ... 171 7.2.4 Zusammenfassung der Hydrodynamik gravitationsgetriebener Flüssigkeitsfilme ... 180 7.3 Reinigungsverhalten gravitationsgetriebener Flüssigkeitsfilme ... 182 7.3.1 Reinigungskinetik ... 182 7.3.2 Gereinigte Zonen ... 185 7.3.3 Einfluss des Flächenverschmutzungsgewichtes ... 187 7.3.4 Einfluss der Betriebsparameter ... 188 7.3.5 Reinigungseffizienz ... 191 7.3.6 Einfluss der Oberfläche ... 193 7.3.7 Fehlerdiskussion ... 195 7.3.8 Zusammenfassung des Reinigungsverhaltens ... 197 8 Vergleich Reinigungsverhalten und Hydrodynamik gravitationsgetriebener Flüssigkeitsfilme ... 198 8.1 Vorbemerkungen zum Vergleich ... 198 8.2 Einfluss Strömungsparameter auf das Reinigungsverhalten ... 198 8.2.1 Einfluss der Filmdicke und Filmdickenverteilung ... 198 8.2.2 Einfluss der Strömungsgeschwindigkeit ... 199 8.3 Einfluss abgeleiteter Größen auf das Reinigungsverhalten ... 201 8.3.1 Einfluss der Wandschubspannung ... 201 8.3.2 Einfluss der Grenzschichtdicke ... 202 8.4 Zusammenfassung des Vergleiches zwischen Reinigungsverhalten und Hydrodynamik ... 205 9 Optimierungsansatz: diskontinuierliche Flüssigkeitsfilme ... 207 10 Zusammenfassung und Ausblick ... 211 Literaturverzeichnis ... 214 Anhangverzeichnis ... 229
36

Two dimensional Maximal Supergravity, Consistent Truncations and Holography

Ortiz, Thomas 07 July 2014 (has links) (PDF)
A complete non trivial supersymmetric deformation of the maximal supergravity in two dimensions is achieved by the gauging of a SO(9) group. The resulting theory describes the reduction of type IIA supergravity on an AdS_2 x S^8 background and is of first importance in the Domain-Wall / Quantum Field theory correspondence for the D0-brane case. To prepare the construction of the SO(9) gauged maximal supergravity, we focus on the eleven dimensional supergravity and the maximal supergravity in three dimensions since they give rise to important off-shell inequivalent formulations of the ungauged theory in two dimensions. The embedding tensor formalism is presented, allowing for a general desciption of the gaugings consistent with supersymmetry. The SO(9) supergravity is explicitly constructed and applications are considered. In particular, an embedding of the bosonic sector of the two-dimensional theory into type IIA supergravity is obtained. Hence, the Cartan truncation of the SO(9) supergravity is proved to be consistent. This motivated holographic applications. Therefore, correlation functions for operators in dual Matrix models are derived from the study of gravity side excitations around half BPS backgrounds. These results are fully discussed and outlooks are presented.
37

Modelling Losses in Flood Estimation

Ilahee, Mahbub January 2005 (has links)
Flood estimation is often required in hydrologic design and has important economic significance. For example, in Australia, the annual spending on infrastructure requiring flood estimation is of the order of $650 million ARR (I.E. Aust., 1998). Rainfall-based flood estimation techniques are most commonly adopted in practice. These require several inputs to convert design rainfalls to design floods. Of all the inputs, loss is an important one and defined as the amount of precipitation that does not appear as direct runoff. The concept of loss includes moisture intercepted by vegetation, infiltration into the soil, retention on the surface, evaporation and loss through the streambed and banks. As these loss components are dependent on topography, soils, vegetation and climate, the loss exhibits a high degree of temporal and spatial variability during the rainfall event. In design flood estimation, the simplified lumped conceptual loss models were used because of their simplicity and ability to approximate catchment runoff behaviour. In Australia, the most commonly adopted conceptual loss model is the initial losscontinuing loss model. For a specific part of the catchment, the initial loss occurs prior to the commencement of surface runoff, and can be considered to be composed of the interception loss, depression storage and infiltration that occur before the soil surface saturates. ARR (I. E. Aust., 1998) mentioned that the continuing loss is the average rate of loss throughout the remainder of the storm. At present, there is inadequate information on design losses in most parts of Australia and this is one of the greatest weaknesses in Australian flood hydrology. Currently recommended design losses are not compatible with design rainfall information in Australian Rainfall and Runoff. Also design losses for observed storms show a wide variability and it is always difficult to select an appropriate value of loss from this wide range for a particular application. Despite the wide variability of loss values, in the widely used Design Event Approach, a single value of initial and continuing losses is adopted. Because of the non-linearity in the rainfall-runoff process, this is likely to introduce a high degree of uncertainty and possible bias in the resulting flood estimates. In contrast, the Joint Probability Approach can consider probability-distributed losses in flood estimation. In ARR (I. E. Aust., 1998) it is recommended to use a constant continuing loss value in rainfall events. In this research it was observed that the continuing loss values in the rainfall events were not constant, rather than it decays with the duration of the rainfall event. The derived loss values from the 969 rainfall and streamflow events of Queensland catchments would provide better flood estimation than the recommended design loss values in ARR (I. E. Aust., 1998). In this research, both the initial and continuing losses were computed using IL-CL loss model and a single median loss value was used to estimate flood using Design Event Approach. Again both the initial and continuing losses were considered to be random variables and their probability distribution functions were determined. Hence, the research showed that the probability distributed loss values can be used for Queensland catchments in near future for better flood estimate. The research hypothesis tested was whether the new loss value for Queensland catchments provides significant improvement in design flood estimation. A total of 48 catchments, 82 pluviograph stations and 24 daily rainfall stations were selected from all over Queensland to test the research hypothesis. The research improved the recommended design loss values that will result in more precise design flood estimates. This will ultimately save millions of dollars in the construction of hydraulic infrastructures.
38

Objekty živočišné výroby z hlediska hlukové zátěže okolního prostředí / Objects of livestock production in terms of ambient noise levels

LENC, Jan January 2011 (has links)
This thesis deals with the evaluation of noise exposure in the agricultural cooperative Hosín ? Dobrejovice. The aim of this work was to measure noise levels in the dairy barn area and its surroundings, during these processes work: milking, feeding, removal of excrement, bedding etc. Measurements were carried out in summer and autumn. During the measurement noise was the largest source of agricultural equipment. The results revealed that noise pollution resulting from the operation of agricultural cooperatives Dobrejovice is fair and negative influence on noise pollution does not occur.
39

Two dimensional Maximal Supergravity, Consistent Truncations and Holography / Supergravité maximale bidimensionnelle, troncatures cohérentes et holographie

Ortiz, Thomas 07 July 2014 (has links)
Nous avons réalisé une déformation non-triviale et complète de la théorie de supergravité maximale en dimension deux. Il s'agit de la supergravité maximale avec groupe de jauge SO(9). Cette théorie décrit de manière effective la supergravité de type IIA sur un espace-temps produit AdS_2 x S^8. Elle joue ainsi un rôle important dans la correspondance Gravité / Théorie de Jauge appliquée au cas de la D0-brane. Afin de préparer la construction de la supergravité maximale jaugée SO(9), nous nous intéressons aux supergravités maximales en dimension onze et trois, puisqu'elles donnent lieu à différentes formulations non équivalentes de la théorie bidimensionnelle non jaugée. Le formalisme d' « Embedding tensor » est ensuite présenté. Il permet de déterminer l'ensemble des groupes de jauges compatibles avec la supersymétrie maximale. La supergravité SO(9) est dès lors explicitement construite et ouvre la voie à deux applications importantes. P our commencer, nous avons réalisé l'inclusion d'un sous-secteur bosonique de la théorie SO(9), la troncature de Cartan, dans la supergravité de type IIA à dix dimensions d'espace-temps. Il s'agit d'une inclusion cohérente. Cela a motivé la deuxième application, de nature holographique. Ainsi, à partir du sous-secteur de Cartan de la supergravité SO(9), et en particulier de la découverte d'états fondamentaux de type « half-BPS », nous avons calculé un ensemble de fonctions de corrélation à un et deux points associées à des opérateurs de modèles de matrice duaux. Nous avons conclu en un résumé de nos travaux et en la présentation d'intéressantes perspectives. / A complete non trivial supersymmetric deformation of the maximal supergravity in two dimensions is achieved by the gauging of a SO(9) group. The resulting theory describes the reduction of type IIA supergravity on an AdS_2 x S^8 background and is of first importance in the Domain-Wall / Quantum Field theory correspondence for the D0-brane case. To prepare the construction of the SO(9) gauged maximal supergravity, we focus on the eleven dimensional supergravity and the maximal supergravity in three dimensions since they give rise to important off-shell inequivalent formulations of the ungauged theory in two dimensions. The embedding tensor formalism is presented, allowing for a general desciption of the gaugings consistent with supersymmetry. The SO(9) supergravity is explicitly constructed and applications are considered. In particular, an embedding of the bosonic sector of the two-dimensional theory into type IIA supergravity is obtained. Hence, the Cartan truncation of the SO(9) supergravity is proved to be consistent. This motivated holographic applications. Therefore, correlation functions for operators in dual Matrix models are derived from the study of gravity side excitations around half BPS backgrounds. These results are fully discussed and outlooks are presented.
40

Compatible discretizations for Maxwell equations

He, Bo 22 September 2006 (has links)
No description available.

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