<p>Lengthy waiting times have been a problem in Swedish health services for many years. In 1992, Sweden implemented a national maximum waiting-time guarantee (MWG) through an agreement between the Swedish Government and the Federation of Swedish County Councils. The “guarantee” assured patients that the waiting time between the decision-to-treat and the treatment itself would not exceed three months. The national MWG covered twelve different treatments/interventions and remained in force for five years. This dissertation describes the genesis of the MWG, its implementation, and its effects.</p><p>Four papers serve as a foundation for the dissertation. Paper I describes how the guarantee was implemented during the first two years. Paper II studies the impact that the MWG had on cataract surgery. Paper III uses the results of two questionnaire surveys of department heads to explain why the MWG, although successfully launched, became increasingly difficult to maintain. Paper IV analyses data from the national cataract register to determine how production and waiting times in cataract surgery were affected by termination of the MWG.</p><p>This dissertation confirms that waiting time for health care is a complex phenomenon resulting from multiple causes. “Guarantees” are of particular interest because they define what constitutes too long in reference to waiting times. Beyond that, they are only a framework for developing a plan of action. The positive effects of the MWG were transient and based on rationalisation, introduction of new technology, and stricter prioritisation. The MWG contributed towards empowering patients and slowing the expansion of treatment indications, but it was unsuccessful in levelling out the wide regional variations in surgical rates.</p>

Lengthy waiting times have been a problem in Swedish health services for many years. In 1992, Sweden implemented a national maximum waiting-time guarantee (MWG) through an agreement between the Swedish Government and the Federation of Swedish County Councils. The “guarantee” assured patients that the waiting time between the decision-to-treat and the treatment itself would not exceed three months. The national MWG covered twelve different treatments/interventions and remained in force for five years. This dissertation describes the genesis of the MWG, its implementation, and its effects. Four papers serve as a foundation for the dissertation. Paper I describes how the guarantee was implemented during the first two years. Paper II studies the impact that the MWG had on cataract surgery. Paper III uses the results of two questionnaire surveys of department heads to explain why the MWG, although successfully launched, became increasingly difficult to maintain. Paper IV analyses data from the national cataract register to determine how production and waiting times in cataract surgery were affected by termination of the MWG. This dissertation confirms that waiting time for health care is a complex phenomenon resulting from multiple causes. “Guarantees” are of particular interest because they define what constitutes too long in reference to waiting times. Beyond that, they are only a framework for developing a plan of action. The positive effects of the MWG were transient and based on rationalisation, introduction of new technology, and stricter prioritisation. The MWG contributed towards empowering patients and slowing the expansion of treatment indications, but it was unsuccessful in levelling out the wide regional variations in surgical rates.

La tesi descriu dos algorismes relatius al transport públic que actuen en sèrie. El primer genera una xarxa d'autobusos urbans entesa com a un conjunt de línies o be en modifica una de ja existent de forma que minimitzi el temps total de viatge en una ciutat. Es tracta d'un algorisme iteratiu que tracta les línies d'una en una i aquestes al seu torn de nus en nus. El segon algorisme dit d'assignació un cop coneguda la xarxa i la flota d'autobusos minimitza el temps total de viatge per mitja de l'assignació d'autobusos a les línies.

We propose a situation in which a single employee is responsible for processing incoming claims to an insurance company that can be classified as being one of two possible types. More specifically, we consider a priority-based system having separate buffers to store high priority and low priority incoming claims. We construct a mathematical model and perform queueing analysis to evaluate the performance of this priority-based system, which incorporates the possibility of claims being redistributed, lost, or prematurely processed.

We propose a situation in which a single employee is responsible for processing incoming claims to an insurance company that can be classified as being one of two possible types. More specifically, we consider a priority-based system having separate buffers to store high priority and low priority incoming claims. We construct a mathematical model and perform queueing analysis to evaluate the performance of this priority-based system, which incorporates the possibility of claims being redistributed, lost, or prematurely processed.

Different applications of communication networks have different requirements that depend on the type of application. We consider the problem of differentiating between delay-sensitive applications based on their average delay requirements, as may be of interest in signalling networks. We consider packets of different classes that are to be transmitted on the same link with different average delay requirements, to reside in separate queues with the arrival statistics for the queues being specified. This statistical multiplexer has to schedule packets from different queues in so that the average delays of the queues approach the specified target delays as quickly as possible. For simplicity, we initially consider a discrete-time model with two queues and a single work-conserving server, with independent Bernoulli packet arrivals and unit packet service times. With arrival rates specified, achieving mean queue lengths in a ratio which corresponds to the ratio of target mean delays is a means of achieving individual target mean delays. We formulate the problem in the framework of Markov decision theory. We study two scheduling policies called Queue Length Balancing and Delay Balancing respectively, and show through numerical computation that the expectation of magnitude of relative error in θ (1/m) and θ (1/√m) respectively, and that the expectation of the magnitude of relative error in weighted average delays decays as θ (1/√m) and θ (1/m) respectively, where m is the averaging interval length. We then consider the model for an arbitrary number of queues each with i.i.d. batch arrivals, and analyse the errors in the average delays of individual queues. We assume that the fifth moment of busy period is finite for this model. We show that the expectation of the absolute value of error in average queue length for at least one of the queues decays at least as slowly as θ (1/√m), and that the mean squared error in queue length for at least one of the queues decays at least as slowly as θ (1/m). We show that the expectation of the absolute value of error in approximating Little’s law for finite horizon is 0 (1/m). Hence, we show that the mean squared error in delay for at least one of the queues decays at least slowly as θ (1/m). We also show that if the variance of error in delay decays for each queue, then the expectation of the absolute value of error in delay for at least one of the queues decays at least as slowly as θ (1/√m).

Wartezeiten von durchschnittlich mehreren Monaten sind auch nach Inkrafttreten des Psychotherapeutengesetzes in der deutschen Psychotherapieversorgung die Regel. Behandlungsbedürftige Störungen, für die ein Behandlungswunsch besteht, unversorgt zu lassen, ist weder unter ethischen, noch praktischen und therapeutischen Gesichtspunkten vertretbar. Aus diesem Grund schlagen viele Praktiker ihren wartenden Patienten niedrigschwellige Selbsthilfeangebote vor, die von psychoedukativen Informationen über Bibliotherapie bis zu Gruppenangeboten reichen. Die vorliegende Arbeit gibt einen Überblick über verschiedene Möglichkeiten, wartende Psychotherapiepatienten gut auf die bevorstehende Therapie vorzubereiten und während der Wartezeit zugleich sekundäre Prävention zu betreiben. Hierbei muss nach unserer Einschätzung vor allem die Maxime gelten, dass die vorgeschlagenen Maßnahmen mit dem Rational der darauf folgenden Therapie vereinbar sein sollten. / Even after the new psychotherapy law has been implemented, waiting times of several months remain rather common in the German mental health care system. For ethical, practical, and therapeutic reasons, however, patients who are in serious need of treatment should not be left unattended. Many practitioners therefore suggest self-help treatments such as psychoeducational information, bibliotherapy, or supportive groups to their waiting patients. The present study provides an overview on possibilities of preparing waiting psychotherapy patients for their upcoming therapy as well as implementing secondary prevention during the waiting time. As a basic, we suggest that the proposed methods should be in line with the treatment rationale of the subsequent therapy. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

This dissertation is concerned with the tail asymptotics of queueing networks with subexponential service time distributions. Our objective is to investigate the tail characteristics of key performance measures such as cycle times and waiting times on a variety of queueing models which may arise in many applications such as communication and manufacturing systems. First, we focus on a general class of closed feedforward fork and join queueing networks under the assumption that the service time distribution of at least one station is subexponential. Our goal is to derive the tail asymptotics of transient cycle times and waiting times. Furthermore, we argue that under certain conditions the asymptotic tail distributions remain the same for stationary cycle times and waiting times. Finally, we provide numerical experiments in order to understand how fast the convergence of tail probabilities of cycle times and waiting times is to their asymptotic counter parts. Next, we consider closed tandem queues with finite buffers between stations. We assume that at least one station has a subexponential service time distribution. We analyze this system under communication blocking and manufacturing blocking rules. We are interested in the tail asymptotics of transient cycle times and waiting times. Furthermore, we study under which conditions on system parameters a stationary regime exists and the transient results can be generalized to stationary counter parts. Finally, we provide numerical examples to understand the convergence behavior of the tail asymptotics of transient cycle times and waiting times. Finally, we study open tandem queueing networks with subexponential service time distributions. We assume that number of customers in front of the first station is infinite and there is infinite room for finished customers after the last station but the size of the buffer between two consecutive stations is finite. Using (max,+) linear recursions, we investigate the tail asymptotics of transient response times and waiting times under both communication blocking and manufacturing blocking schemes. We also discuss under which conditions these results can be generalized to the tail asymptotics of stationary response times and waiting times. Finally, we provide numerical examples to investigate the convergence of the tail probabilities of transient response times and waiting times to their asymptotic counter parts.

Submitted by Ronildo Prado (ronisp@ufscar.br) on 2017-08-16T18:49:11Z No. of bitstreams: 1 DissVM.pdf: 10400529 bytes, checksum: 6f3a8dfea497dd3a1543a2b5847ad36e (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-08-16T18:49:21Z (GMT) No. of bitstreams: 1 DissVM.pdf: 10400529 bytes, checksum: 6f3a8dfea497dd3a1543a2b5847ad36e (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-08-16T18:49:27Z (GMT) No. of bitstreams: 1 DissVM.pdf: 10400529 bytes, checksum: 6f3a8dfea497dd3a1543a2b5847ad36e (MD5) / Made available in DSpace on 2017-08-16T18:49:35Z (GMT). No. of bitstreams: 1 DissVM.pdf: 10400529 bytes, checksum: 6f3a8dfea497dd3a1543a2b5847ad36e (MD5) Previous issue date: 2017-04-07 / Não recebi financiamento / Let {Xn} be a sequence of i.i.d. random variables taking values in an enumerable alphabet. Given a finite collection of words, we observe this sequence till the moment T at which one of these words appears as a run. In this work we apply the martingale approach introduced by Li (1980) and Gerber e Li (1981) in order to study the waiting time until one of the words occurs for the first time, the mean of T and the probability of a word to be the first one to appear. / Seja {Xn} uma sequência de variáveis aleatórias i.i.d. assumindo valores num alfabeto enumerável. Dada uma coleção de palavras finita, observamos esta sequência até o momento T em que uma dessas palavras apareça emX1,X2, .... Neste trabalho utilizamos a abordagem de martingais, introduzida por Li (1980) e Gerber e Li ( 981), para estudar o tempo de espera até que uma das palavras ocorra pela primeira vez, o tempo médio de T e a probabilidade de uma palavra ser a primeira a aparecer.

Au moment où la Martinique découvre, non sans stupéfaction, que les jeunes de 18 à 25 ans représentent la classe d’âge la plus pauvre de l’île − ils représentent 12,3% des personnes reçues au Secours Catholique −, cette thèse jette un regard inquiet sur les jeunes qui sortent de l’école sans qualification professionnelle. Le temps de latence qui les met à rude épreuve – c’est la période qui va de la sortie du système scolaire à la stabilisation professionnelle − s’est considérablement allongé. De deux ans il est passé à cinq ans. Ces jeunes sont éjectés d’un système scolaire, resté très élitiste. Les traumas qui les assaillent risquent fort de compromettre le processus qui participe de leur individuation, de leur réalisation. L’objectif de cette thèse est d’analyser les manques, les besoins de cette population, et, au vu des résultats obtenus, de proposer des alternatives. L’approche est qualitative. Elle tente de comprendre l’expérience humaine en situation de chômage. Elle tente d’explorer les difficultés des jeunes sans qualification professionnelle, afin de voir comment il est possible d’améliorer leur situation. Et de manière à prévenir en faveur de cette jeunesse martiniquaise, trop souvent en proie à la spirale de la violence, elle propose des pratiques culturelles, artistiques et musicales. / At a time when Martinique is discovering with amazement, that youths from 18 to 25 are the poorest part of the island populationthey are 12.3% of those coming to the Catholic relief this thesis focuses on the serious problem of young people leaving school without qualifications. The very difficult period of waiting time  that is mean the period that goes from their leaving the school system to a professional stabilization  has risen from two years to five years. These young people are ejected from a school system that is still very selective. Their traumas are so serious that they can compromise the process leading them to their individuation, to their achievement. In this thesis we aim at analyzing the lacks, the needs of this population and then after observing the results obtained, at proposing other alternatives. The approach is qualitative. It attempts to understand the human experience in a situation of unemployment. It tries to explore their difficulties to see how it is possible to improve their situation. And to prevent Martinique youth from being too often in the grip of the spiral of violence, it offers cultural, artistic and musical practices.