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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.
61

Database Engineering Process Modelling/Modélisation des processus d'ingénierie des bases de données

Roland, Didier 15 May 2003 (has links)
One of the main current research activities in Software engineering is concerned about modelling the development process of huge softwares in order to bring some help to the engineer to design and maintain an application. In general, every design process is seen as rational application of transformation operators to one or more products (mainly specifications) in order to produce new products that satisfy to some given criteria. This modelling mainly allows a methodological guidance. Indeed, at each step of the process, the set of pertinent activities and types of products are proposed to the designer, without any other. This guidance may possibly be reinforced with some help. Furthermore, this modelling allows to document the process with its history, ie with a representation of performed actvities. This history is itself the basis of maintenance activities. Two examples : a Replay function that allows, during a modification, to do (automatically or assisted) the same activities as during the design, and Reverse Engineering that allows to recover not only some technical and functional documentation of an application, but also a plausible history of its design. The thesis aims at elaborating a general model of design processes, applying it to database engineering and implementing it in the DB-MAIN CASE tool. It will be done in four phases : 1. elaboration of a model, a method specification language and a history representation 2. evaluation of this model with the specification of classical methods and case studies 3. methodological recommandation proposals for the elaboration of design methods 4. development and integration of some methodological control functions in the DB-MAIN CASE tool; this includes an extension of the repository, the definition of the interface of the methodological functions, the development of the methodological engine and the development of an history processor (analysis, replay,...)./Un des principaux sujets de recherche actuels dans le monde de l'ingénierie logicielle concerne la modélisation des processus de développement de grosses applications afin d'apporter de l'aide aux ingénieurs pour concevoir et maintenir leurs applications. En général, un processus de conception est vu comme l'application rationnelle d'opérateurs de transformation à un ou plusieurs produits (généralement des spécifications) pour obtenir de nouveaux produits qui satisfont une série de critères donnés. Cette modélisation permet principalement une aide méthodologique: à chaque étape du processus, seul l'ensemble des outils pertinents est mis à disposition du concepteur. Ce guidage peut être renforcé par des messages d'aide. Cette aide s'étend l'enregistrement de l'historique du processus, c'est-à-dire d'une représentation des actions entreprises. Cet historique peut lui-même être à la base d'activités de maintenance. Deux exemples: une fonction qui permet de rejouer, lors d'une modification, de manière automatique ou assistée, les mêmes actions que pendant la conception, et la rétro-ingénierie qui permet de recouvrer non seulement la documentation technique et fonctionnelle d'une application, mais aussi un historique plausible de la conception originelle. La thèse s'attache à élaborer un modèle général de processus de conception, à l'appliquer au monde des bases de données et à l'implémenter dans l'AGL DB-MAIN. Cela, en 4 phases: 1. Élaboration d'un modèle, d'un langage de spécification (MDL) et d'une représentation des historiques 2. Évaluation de ce modèle avec des méthodes de spécification classiques et études de cas 3. Propositions de recommandations méthodologiques pour l'élaboration de méthodes d'ingénierie 4. Développement et intégration de fonctions de contrôle méthodologique dans l'atelier DB-MAIN; ceci inclut l'extension du référentiel, la définition de l'interface homme-machine des fonctions méthodologiques et le développement du moteur méthodologique.
62

A study of some aspects of gas-slag-metal interactions : Towards dynamic process model and control

Ek, Mattias January 2012 (has links)
The present thesis deals with the development of a new type of dynamic model for metallurgical reactors. It also covers some of the theoretical aspects of steelmaking that is necessary to include in such an application. The thesis consists of modeling work, high temperature experiments and cold model experiments. Two different aspects of slags in the oxygen steelmaking were investigated. In the first study, slag samples were equilibrated with copper at 1923K in order to study their capacities in capturing phosphorous. Some of the samples were liquid-solid mixtures. The solid phases in these samples were identified by SEM analysis. The identified phases were found to agree well with Thermocalc calculations while the amount of solid fractions didn’t. The phosphorous distribution between the different phases was examined. The phosphate capacities of the samples were evaluated. The MgO content didn’t show any appreciable impact on the phosphate capacity. Furthermore the activities of FeO in the liquid slag samples were calculated and were found to deviate positively from ideality. In the second study the foaming height of CaO-SiO2-FeO slags by the reaction with hot metal was investigated. It was found that the foaming height increased with increasing FeO content up to 20-25%. The foaming height was seen to decrease with increased viscosity. The present results indicated that simply using foaming index for converter slag might lead to wrong conclusion. Simulation experiments using cold model at room temperature were conducted. Cold model experiments were carried out in order to study the penetration depth due to an impinging gas jet on the surface of a liquid metal. The liquid alloy Ga-In-Sn was used to simulate steel. And an HCl solution was used to simulate the slag. A comparison with predictions of existing models was made and a new model parameter was suggested. The observation of the movement of metal droplets generated by the gas jet was also made. The low velocity of droplets suggested that the turbulent viscosity played important role and the droplets could have long resident time in the slag. Furthermore a study of the effect of gas flow rate on homogenization and inclusion removal in a gas stirred ladle was carried out. Both industrial trials and cold model experiments were conducted. As an auxiliary tool CFD was used to predict the mixing times and was found to agree well with both the model experiments and industrial data. The increase of flow rate of inert gas would not improve the mixing substantially at higher flow rates. The water model study showed also that the gas flow rate had negligible effect on the rate of inclusion removal. Both the experiments and CFD calculation strongly suggested that low gas flow rate should be applied in the ladle treatment. Lastly a new approach to a dynamic process model of 300 ton BOF converter was made. The main feature was to utilize the velocity vectors obtained by CFD simulation. In the standalone model, the steel melt domain was sliced into 1000 cells. Based on the imported velocity vectors from the CFD calculation, the mass transfer of carbon and phosphorus was calculated taking into account the slag metal reactions. The mass exchange between slag and metal was considered to be dominated by the metal droplet formation due to oxygen jet. The convergence of the model calculation and the promising comparison between the model prediction and the industrial data strongly suggested that the proposed approach would be a powerful tool in dynamic process control. However, more precise descriptions of other process aspects need to be included before the model can be practically employed in a dynamic controlling system. / <p>QC 20120829</p>
63

Impact of Meetings in Software Process Improvement

Naeem, Qaiser January 2012 (has links)
In this thesis we have described the role of meetings in software development and their impact on process improvement. We have investigated some factors; which could be used to improve organization process e.g. strategic management, understanding of business and its processes, learning and evaluation of resources. A survey has been conducted with the help of a questionnaire to analyze the meeting practices in the small and medium scale software companies. A process model and a simulation have been designed to measure the impacts of meetings on the productivity of organizations which claim the utilization of agile process. The designed model is an extension of Hamid &amp; Madnick’s process model and the simulation is a newly developed web based application that performs meeting scheduling. The application is developed with the concept of Software As A Service (SAAS) by using the Framework Symfony and programming languages PHP and MySQL.
64

A Methodology of SSA&D Modeling for Embedded Systems

Hsu, Wen-cheng 22 July 2010 (has links)
Structured technique is the traditional and the popular systems analysis and design language. With the rapid progress and development of information technology, embedded systems have penetrated into most of the equipments which we used daily. Over the past few years a considerable effort has been made in modeling the platform independent model (PIM) for business information systems. However, the detailed guideline for modeling the PIM of embedded systems is lacking. This study proposed a PIM modeling methodology with structured technique for embedded systems. The structured modeling process is consisted of three parts: requirement modeling, process modeling and module modeling. For each part, its modeling tool, modeling processes and rules are provided. The research methodology is articulated using the design science research methodology. A usability evaluation is performed to demonstrate its applicability with a real-world embedded system case. The evaluation results indicated that with this proposed method, the system developer can easily and effectively analyze and design the embedded systems with structured technique.
65

Flow Sheet Optimization By The Concept Of Sustainable Development: Alumina Industry

Kurucak, Abdurrahman 01 February 2010 (has links) (PDF)
In this study, effects of changes in various parameters of the Bayer process on the amount of &ldquo / red mud&rdquo / , which has many environmental drawbacks, were examined in accordance with the principles of &ldquo / sustainable development&rdquo / . The production process of SeydiSehir Aluminum Plant is modeled as a case study. First a steady-state mass balance calculation is carried out by incorporating sequential modular approach. Then a model of the Bayer process digester is programmed and several simulations are carried out using this model. Results of the mass balance calculation revealed that changes in the extent of the digestion reaction, which is a function of temperature and caustic concentration, and washing efficiency may have a 2.07% decrease on the amount of red mud produced,which implies nearly 10,000 tons of decline per annum, while amount of hydrate produced is increased by 4.52%. A 7.40 % decrease on the amount of red mud produced on dry basis per kg of hydrate was found to be achievable. Optimum operating temperature for the digester was calculated as 277.3 &deg / C.
66

A Process Modeling Based Method For Identification And Implementation Of Software Development Tool Integration-tuples

Erturkmen, Alpay K 01 March 2010 (has links) (PDF)
Software development is highly dependent on the use of tools. These tools support and automate activities performed in different sub-domains of software development. However, they don&lsquo / t adequately provide or support integration facilities, and act as &amp / #8213 / islands of automation&amp / #8214 / . This restricts their benefits to only specific parts of the process. To reap the benefits of integration, this thesis provides a process modeling based method named PLETIN to identify and implement software development tool integration-tuples. The method aims to present solutions for issues observed in tool integration for software development organizations by delivering an integrated tool set. The proposed solution approach is based on the idea that if there were no integrations between tools at all, users would perform the necessary actions to cooperate different tools. PLETIN is a method for the identification of the candidate integration situations (integration-tuples) from the interactions of users with the tools. These tuples constitute the requirements used to develop integration facilities. The software development process definitions are used as inputs to create process models and provide actual implementations. The research is supported with case-study work to identify the significance of the problems and the applicability of the method as a solution to issues in tool integration.
67

An Automated Tool For Quality Manual Generation From Business Process Models

Aydin, Elif 01 September 2010 (has links) (PDF)
The majority of organizations make their business processes explicit to improve them. Defining business processes manually and modeling them are two alternatives utilized for this purpose. Meanwhile, organizations have quality management systems which are frequently shaped by frameworks. The most commonly used process improvement frameworks in the IT sector are ITIL, Cobit, CMMI and ISO 9001. These frameworks indicate the necessity of process documentation and ISO 9001 addresses the name &ldquo / Quality Manual&rdquo / for this purpose. In this thesis, an automated tool is developed for quality manual generation from predetermined business process models. In addition, a case study is performed by means of a systematic approach and its results were discussed with the findings of structured interviews. The aim of the study is to reduce the effort and time required for quality manual preparation and merge quality management activities with process modeling by means of process documentation.
68

The Design and Implementation of a Business Process Analyzer

Yu, Chia-ping 21 May 2000 (has links)
Business process reengineering (BPR) has been considered as one of the key approaches to increasing the competitive edge of many modern enterprises. Many big enterprises have taken diversified degree of reengineering to their business processes. The importance of understanding the existing business processes and evaluating the new business processes before they are actually deployed is commonly recognized. Without careful examination of the existing and new business processes, the change in business process. In this research, we look into the business process analysis issues under the scope of BPR. We first examine various models for business processes. As each model is invented with a purpose, e.g., for identifying the critical path in a factory manufacturing environment, for automating workflow in an office environment, etc., they may not be completely suitable for business process analysis. We try to identify the requirements of business process analysis and propose a model to meet these requirements. We finally design and implement a business process analyzer. This business process analyzer use our proposed business process model and is able to answer the queries from the BPR team expressed by our proposed query language.
69

Single event kinetic modeling of solid acid alkylation of isobutane with butenes over proton-exchanged Y-Zeolites

Martinis Coll, Jorge Maximiliano 12 April 2006 (has links)
Complex reaction kinetics of the solid acid alkylation of isobutane with butenes over a proton-exchanged Y-zeolite has been modeled at the elementary step level. Starting with a computer algorithm that generated the reaction network based on the fundamentals of the carbenium ion chemistry, the formation of over 100+ product species has been modeled in order to gain understanding of the underlying phenomena leading to rapid catalyst deactivation and product selectivity shifts observed in experimental runs. An experimental investigation of the solid acid alkylation process was carried out in a fixed bed catalytic reactor operating with an excess of isobutane under isothermal conditions at moderate temperatures (353-393 K) in liquid phase. Experimental data varying with run-time for a set of butene space-times and reaction temperatures were collected for parameter estimation purposes. A kinetic model was formulated in terms of rate expressions at the elementary step level including a rigorous modeling of deactivation through site coverage. The single event concept was applied to each rate coefficient at the elementary step level to achieve a significant reduction in the number of model parameters. Based on the identification of structural changes leading to the creation or destruction of symmetry axes and chiral centers in an elementary step, formulae have been developed for the calculation of the number of single events. The Evans-Polanyi relationship and the concept of stabilization energy were introduced to account for energy levels in surface-bonded carbenium ions. A novel functional dependency of the stabilization energy with the nature of the carbenium ion and the carbon number was proposed to account for energy effects from the acid sites on the catalyst. Further reductions in the number of parameters and simplification of the equations for the transient pseudohomogeneous one-dimensional plug-flow model of the reactor were achieved by means of thermodynamic constraints. Altogether, the single event concept, the Evans-Polanyi relationship, the stabilization energy approach and the thermodynamic constraints led to a set of 14 parameters necessary for a complete description of solid acid alkylation at the elementary step level.
70

Towards an Integration of Business Process Modeling and Object-Oriented Software Development

Loos, Peter, Fettke, Peter 15 May 2001 (has links) (PDF)
The successful development and implementation of business information systems requires an integrated approach which includes the seamless design of both the business processes and the information systems supporting the business processes. Therefore, several frameworks and modeling methods have been developed for an integrated modeling of the entire enterprise with respect to both organizational and information systems aspects. Due to the architecture of most existing business information systems, these approaches were usually based on traditional software development paradigms rather than on object-orientation. On the other hand, object-oriented modeling methods used to cover only aspects which are close to implementation, but not the business processes. Currently, however, these two worlds are mov-ing closer together because there are several benefits using business process models during object-oriented software development. This paper describes an approach for integrating business process and object-oriented modeling methods. With this approach, it is possible to model the relevant aspects of a company’s business processes and its object-oriented information systems without the need for switching between different modeling paradigms or for trans-lating between different modeling languages.

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