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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

Exploring the experiences of transitional care from child and adolescent mental health services to adult mental health services : the perspectives of professionals, parents and young people

Chopra, Gurpreet Kaur January 2016 (has links)
Transitional care is an important process for professionals to consider, particularly as recent studies have shown how a mental health difficulty in adolescence will persist into adulthood. This indicates that a number of those seen in Child and Adolescent mental health services are likely to make the transition into Adult services. For professionals from both services, barriers can arise when supporting young people across service boundaries and recent studies have stated that the current practice of transitional care in mental health is deemed to be problematic. However at the time of conducting this study, there was a paucity of literature, therefore the aim of the study was to add to the existing knowledge. The study followed a Social Constructivist grounded theory (Charmaz, 2014) approach to explore the experience of stakeholders of the transition process. Semi-structured interviews were conducted with professionals, young people and parents. There were a total of eight interviews which were transcribed and analysed. The findings present the core category as Facing the transition, with three sub- categories: Changing status, Manoeuvring the boundaries and Reflections on the process. The tentative theory explains how facing the transition involves stakeholders adjusting to the changing status of the service user. This category triggers the service transition but also describes how societal perceptions about adulthood influence the expectations placed on young people. Manoeuvring the boundaries describes and explains service transition, identifying a range of barriers and strategies to overcome these. One of the most significant barriers was identified as cultural differences between the two services. The third category describes how stakeholders make sense of their experiences, and how these are managed within the therapeutic relationship.
2

Control of an automated storage and retrieval system

Lawrence, Terry 26 January 2010 (has links)
<p>The Robotics and Automation Laboratory at Virginia Polytechnic Institute and State University contains a Flexible Machining and Assembly System (FMAS) and an Automated Storage and Retrieval System (AS/RS). These systems were developed for educational purposes to emulate a typical flexible manufacturing process in industry. The AS/RS hardware was designed and constructed in a previous project by Mark Eaglesham. His project consisted of hardware development only and did not include control system development.</p> <p> The objective of this project is to design a set of software primitives to control the AS/RS. This set of primitive control sequences for the AS/RS could be used by future students to further develop the AS/RS control system at the device control level or to integrate the AS/RS with the FMAS at the workcell control level. The set of control primitives were developed in Relay Ladder Logic (RLL) on a Texas Instruments 565 Programmable Logic Controller (PLC). The set of primitives include the following functions: initialize the system, store a pallet, retrieve a pallet, move to a specified location, and shutdown the system.</p> <p> A communications dialog was developed for command and control interaction between the PLC and the workcell control computer. This protocol includes various functions to manage the AS/RS's operations. These functions commands from the workcell controller indicating what operation is needed and response from the AS/RS indicating its status and system error messages.</p> <p> In order to test the AS/RS a program to simulate the workcell controller was developed. This project report includes a description of a test program developed using QuickC. Due to hardware difficulties, this test program was not implemented. The AS/RS primitives were tested using Texas Instrument's TISOFT RLL development and monitoring software package.</p> / Master of Engineering
3

Opportunities, Challenges and Use Cases of Digitization within the Semiconductor Industry

Schneider, Germar, Keil, Sophia, Luhn, Gerhard 16 September 2019 (has links)
Over the last years, Infineon Dresden Technologies has continuously been working on offering innovative products and enhancing the productivity of their wafer fabrication areas by increasing fab capacities as well as increasing automation in their 200 and 300 mm wafer manufacturing plants to improve productivity. One of the most important success factors is use of powerful automated material handling systems (AMHS) combined with the digitization of core processes within the whole company. Digitization supports converting a highly automated fab into a “smart fab” by horizontal and vertical integration of the internal supply chains. Within this paper, the authors provide an overview of three use cases for continuous improvement of the manufacturing process through use of automation and digitization to enhance the profitability of the semiconductor manufacturing plant.
4

Optimal and Approximate Algorithms for the Multiple-Lots-per-Carrier Scheduling and Integrated Automated Material Handling and Lot Scheduling Problems in 300mm Wafer Fabs

Wang, Lixin 22 October 2008 (has links)
The latest generation of semiconductor wafer fabs produce Integrated Circuits (ICs) on silicon wafers of 300mm diameter. In this dissertation, we address the following two types of (new) scheduling problems that are encountered in this generation of wafer fabs: multiple-lots-per-carrier scheduling problem (MLCSP) and integrated automated material handling and lot scheduling problem (IMHLSP). We consider several variations of the MLCSP depending upon the number of machines used, the prevailing processing technology of the machines, and the type of objective functions involved. For the IMHLSP, we study two instances, one with infinite number of vehicles and the other with finite number of vehicles. We begin by introducing a single-machine, multiple-lots-per-carrier with single-wafer-processing-technology scheduling problem for the objective of minimizing the total completion time (MLCSP1). The wafer carrier is a front-opening unified pod (FOUP) that can hold a limited number of wafers. The problem is easy to solve when all the lots are of the same size. For the case of different lot sizes, we first relax the carrier (FOUP) capacity and propose a dynamic programming-based algorithm, called RelaxFOUP-DP, which enables a quick determination of its optimal solution that serves as a lower bound for the problem with limited FOUP capacity. Then, a branch-and-bound algorithm, designated as MLCSP1-B&B, is developed that relies on the lower bound determined by the RelaxFOUP-DP algorithm. Numerical tests indicate that MLCSP1-B&B finds optimal solutions much faster than the direct solution of the MLCSP1 model by the AMPL CPLEX 10.1 Solver. In fact, for the medium and low density problems, the MLCSP1-B&B algorithm finds optimal solutions at the starting node (node zero) itself. Next, we consider a single-machine, multiple-lots-per-carrier with single-carrier-processing-technology scheduling problem for the objective of minimizing total completion time (MLCSP2). As for the case of MLCSP1, the optimal solution for the case in which all the lots are of the same size can be obtained easily. For the case of different lot sizes, we determine a lower bound and an upper bound for the problem and prove the worst-case ratios for them. Subsequently we analyze a two-machine flow shop, multiple-lots-per-carrier with single-wafer-processing-technology scheduling problem for the objective of minimizing the makespan (MLCSP3). We first consider a relaxed version of this problem, and transform the original problem to a two-machine flow shop lot streaming problem. Then, we propose algorithms to find the optimal capacitated sublot sizes for the case of lots with (1) the same ratio of processing times, and, (2) different ratios of processing times on the machines. Since the optimal solutions obtained from the lot streaming problem may not be feasible to the MLCSP3, we develop heuristic methods based on the heuristic procedures for the bin packing problem. We develop four heuristic procedures for lots with the same ratio of processing times, and another four procedures for lots with different ratios of processing times on the machines. Results of our numerical experimentation are presented that show that our heuristic procedures generate almost optimal solutions in a matter of a few seconds. Next, we address the integrated automated material handling and lot scheduling problem (IMHLSP) in the presence of infinite number of vehicles. We, first, propose a new strong hybrid model, which has the advantages of both segregate and direct models. In the segregate model, a job is always transferred to the stocker after its completion at a station, while in the direct model, it is transferred to the next machine in case that machine can accommodate the jobs; otherwise, the job will stay at current station. The decisions involved in the strong hybrid model are the sequence in which to process the lots and a selection between the segregate and direct models for each lot, whichever optimizes system performance. We show that, under certain conditions about the processing times of the lots, the problem can be approximated by the cases of either infinite buffer or zero-buffer at the machines. Hence, we consider all three cases of the IMHLSP in this chapter, namely, infinite buffer, zero-buffer, and limited buffer sizes. For the strong hybrid model with limited buffer size, we propose a branch-and-bound algorithm, which uses a modified Johnson's algorithm to determine a lower bound. Two upper bounds for this algorithm are also determined. Results of our numerical investigation indicate that our algorithm finds optimal solutions faster than the direct solution of the IMHLSP model by the AMPL CPLEX 10.1 Solver. Experimental results also indicate that for the same problem size, the times required to solve the IMHLSP model with interbay movements are larger than those for intrabay movements. Finally, we investigate the IMHLSP in the presence of limited number of vehicles. Due to the complex nature of the underlying problem, we analyze small-size versions of this problem and develop algorithms for their solution. For some of these problems, we can find optimal solutions in polynomial time. Also, based on our analysis on small-size systems, we have shown why some real-time dispatching (RTD) rules used in real fabs are expected to perform well while not the others. In addition, we also propose some new and promising RTD rules based on our study. / Ph. D.
5

Simulation et optimisation du transport automatise dans la fabrication de semi-conducteurs. / Simulating and Optimizing Automated Transportation in Semiconductor Manufacturing

Kiba, Téwendé Jean-Etienne Arthur 10 November 2010 (has links)
Composants essentiels de tout ordinateur, les semi-conducteurs sont utilisés dans de nombreux secteurs. Les percées technologiques dans ce domaine imposent un rythme vertigineux aux industriels. Tous les deux ans environ, la capacité des puces est doublée et leur prix est divisé par deux. Le diamètre des plaquettes de silicium augmente et, regroupées en lots, les plaquettes sont plus lourdes à transporter. Les systèmes automatiques de transport (AMHS) se présentent comme une excellente alternative. Le prix très élevé des équipements de production fait que l’objectif est de saturer les capacités de production. Pour y parvenir, il est important que le système de transport et de stockage garantisse que les machines n’attendent pas des lots disponibles, et aussi que les lots n’attendent pas une machine disponible.Dans la littérature, la complexité du problème (jusqu’à 700 étapes de fabrication, flux réentrants, etc.) fait que les études de modélisation du transport se font avec de fortes hypothèses sur la production ou inversement. Pourtant, le transport est un service pour la production. Cette thèse propose une approche de modélisation permettant d'intégrer le plus fidèlement possible les contraintes de transport, production et stockage, afin d'améliorer les indicateurs clés de la production. Une analyse détaillée du système a permis de construire un modèle de simulation à événements discrets. Enfin, après une validation industrielle, l'étude complète du modèle a permis d'analyser les paramètres critiques de gestion du transport. Les résultats permettent une meilleure compréhension du système et mettent en exergue d'intéressantes perspectives de recherche. / Essential components of all computers, semiconductors are widely used in many sectors. Quick advances in these technologies force a challenging rhythm to manufacturers. Following the Moore’s Law, chip capacity doubles approximately every two years and prices are divided by two. Thus, the increase of the diameter of wafers to 300 mm makes them heavier to transport in lots. Automated Material Handling Systems (AMHS) are an excellent alternative to tackle this problem. Because of the high price of production equipment, the goal is to use production capacity as much as possible while avoiding to keep too much inventory. To reach this goal, it is important that the transportation and storage system ensures that machines do not wait for available lots, and also that lots do not wait for available machines. In the literature, due to the problem complexity (up to 700 steps, re-entrant flows, etc.), the modeling of transportation is made with strong assumptions on the production or vice-versa. However, transport is a service for production. This thesis aims at providing a modeling approach that allows the integration in details transport, production and storage constraints, in order to improve production key indicators. A detailed understanding of the system allows us to build of a discrete event simulation model which is, in our point of view, the best compromise between the necessary level of details and computational times. Finally, through industrial validations, the complete study of the model allows critical parameters of transport management to be analyzed. The results help to get a better understanding of the system and open interesting research perspectives.
6

Simulation et optimisation du transport automatise dans la fabrication de semi-conducteurs.

Kiba, Téwendé 10 November 2010 (has links) (PDF)
Composants essentiels de tout ordinateur, les semi-conducteurs sont utilisés dans de nombreux secteurs. Les percées technologiques dans ce domaine imposent un rythme vertigineux aux industriels. Tous les deux ans environ, la capacité des puces est doublée et leur prix est divisé par deux. Le diamètre des plaquettes de silicium augmente et, regroupées en lots, les plaquettes sont plus lourdes à transporter. Les systèmes automatiques de transport (AMHS) se présentent comme une excellente alternative. Le prix très élevé des équipements de production fait que l'objectif est de saturer les capacités de production. Pour y parvenir, il est important que le système de transport et de stockage garantisse que les machines n'attendent pas des lots disponibles, et aussi que les lots n'attendent pas une machine disponible.Dans la littérature, la complexité du problème (jusqu'à 700 étapes de fabrication, flux réentrants, etc.) fait que les études de modélisation du transport se font avec de fortes hypothèses sur la production ou inversement. Pourtant, le transport est un service pour la production. Cette thèse propose une approche de modélisation permettant d'intégrer le plus fidèlement possible les contraintes de transport, production et stockage, afin d'améliorer les indicateurs clés de la production. Une analyse détaillée du système a permis de construire un modèle de simulation à événements discrets. Enfin, après une validation industrielle, l'étude complète du modèle a permis d'analyser les paramètres critiques de gestion du transport. Les résultats permettent une meilleure compréhension du système et mettent en exergue d'intéressantes perspectives de recherche.
7

Unga vuxnas transition från barn- och ungdomspsykiatrin till vuxenpsykiatrin : en kvalitativ litteraturöversikt / Young adults transition from child and adolescent mental health services to adult mental health services : a qualitative literature overview

Lindhamre, Peter, Lundgren, Joel January 2021 (has links)
Bakgrund: Den psykiska ohälsan bland unga har ökat de senaste två decennierna. Barn- och ungdomspsykiatrin, BUP, ansvarar för den specialiserade psykiatriska vården för de under 18 år medan vuxenpsykiatrin har ansvaret för de som blivit myndiga. Det finns stora skillnader mellan BUP och vuxenpsykiatrin och övergången mellan vårdformerna innebär en process för de unga vuxna, vilket kan beskrivas i termer av transition.  Syfte: Syftet var att undersöka patienternas beskrivna upplevelser av överföring från barn- och ungdomspsykiatrin till vuxenpsykiatrin. Metod: En kvalitativ litteraturöversikt med systematisk ansats. Resultat: Resultatet baseras på 13 vetenskapliga artiklar med kvalitativ design som sammantaget tydliggör tre övergripande teman som beskriver förändring. De unga vuxna beskriver förändrat ansvar, förändrade relationer samt förändrad identitet till följd av övergången mellan BUP och vuxenpsykiatrin. Slutsats: De unga vuxna beskriver bristande information, ostabila vårdrelationer och en ökad känsla av hopplöshet under transitionen. Fram till att de etablerat en tillitsfull kontakt finns en ökad risk att de unga vuxna faller ur vårdsystemet. En viktig faktor för att säkerställa kontinuitet är att det finns närvarande sjuksköterskor som stöd innan, under och efter transitionen. I detta avseende finns strukturell och individuell förbättringspotential som kräver forskning och metodutveckling.
8

Control of hybrid AMHS considering dynamic transport load transfers between vehicles

Boden, Patrick 07 March 2024 (has links)
This contribution discusses a new control concept (compare Boden et al., 2021) that allows transport load exchange in hybrid AMHS. It focuses on vehicles able to perform load exchange dynamically by splitting transport requests into sub-tasks determined ad-hoc depending on the current system status. Unlike conventional control approaches for hybrid AMHS, our dispatching approach does not rely on high-level control rules which statically split transport tasks in advance.
9

Transport automatisé dans les systèmes de fabrication de semi-conducteurs : nouvelles approches de gestion tactique et opérationnelle

Montoya Torres, Jairo Rafael 29 November 2005 (has links) (PDF)
La fabrication de plaquettes de silicium (wafers) est l'un des processus de fabrication le plus complexes qui existe aujourd'hui. Étant donné à la fois le niveau très élevé d'investissements en équipement et la forte concurrence sur le marché, les fabricants de semi-conducteurs cherchent à rentabiliser au maximum les unités de fabrication (fabs) afin d'obtenir à la fois le meilleur niveau d'utilisation des équipements, un bas niveau d'encours et des temps de cycle de plus en plus courts. Avec l'arrivée de la nouvelle génération de wafers de 300mm de diamètre, des contraintes ergonomiques et de productivité imposent l'automatisation de toute la manutention et le transport des lots de production. Le système automatique de transport joue donc désormais un rôle essentiel pour l'amélioration de la productivité de la fab et la réduction des coûts de production. Cependant, les stratégies de pilotage du système de transport ont été relativement peu étudiées dans la littérature et les travaux existant le considèrent comme étant une entité isolée, ignorant ainsi les effets sur la gestion de la production et des équipements. Du fait de la complexité du processus de fabrication, les études proposées dans la littérature ont traditionnellement été réalisées avec de la simulation à événements discrets.L'objectif de cette thèse est de proposer une méthodologie d'analyse et d'optimisation de la gestion du système automatisé de transport des lots, afin d'améliorer les indicateurs clés de la production. Nous proposons d'abord une modélisation hybride de la fab et du processus de fabrication. Pour cela, nous utilisons une méthodologie basée sur l'identification des ''process'' et de leurs interactions, ainsi qu'une représentation en réseaux de Petri colorés temporisés. Cette conceptualisation nous permet de mieux intégrer les différents composants dans un modèle de simulation. Ensuite, plusieurs stratégies pour la gestion du système de transport des lots (i.e. stratégies de dispatching et de positionnement des chariots) sont analysées. Cette étude est réalisée en couplant des techniques classiques de la Recherche Opérationnelle (i.e. programmation mathématique, méthodes heuristiques) avec le modèle de simulation de la fab. Ainsi, la problématique de gestion du système de transport est abordée à partir du niveau tactique à l'aide d'une démarche d'optimisation qui permet de trouver les valeurs optimales des paramètres du modèle de simulation. Ce dernier permet d'étudier le comportement dynamique du système et facilite l'implémentation des règles pour la gestion opérationnelle. La mise en oeuvre de la démarche hybride optimisation-simulation proposée est analysée dans la structure complexe d'une unité de fabrication de wafers de la nouvelle génération de 300~mm de diamètre.

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