Linear Programming Model Applied to the Resource Schedulling at Queue Systems

The pressure to maintain (or increase) the level of competitiveness in companies leads to an ever-increasing requirement for effective management supported by the variety of existing resources, which tend to interfere into the work of the manager. Particularly, in the case of waiting queues, the most relevant aspect is the combination of the number of multitasking servers assigned to attend and the demand that varies over the course of a day's work. The main objective is to meet the expectations created by the client regarding the opinion of the service that was provided. The contribution that this work proposes to give consists in planning the number of servers adapted to a given demand, not forgetting the valuation associated with the release of resources to perform other tasks related to the business. We use linear programming to determine the optimal number of the servers to serve customers, depending on their hourly availability to fulfill this function and the estimated demand. The model is submitted to four distinct real scenarios, each one reflecting a certain service reality, so that we can evaluate its behavior and possible gains against real situations occurring under the same conditions. The results show the credibility of the model since it reveals in conditions very similar to those of a real situation (translated in one of the scenarios), very little relevant differences

Self-Service System with Rating Dependent Arrivals

A multi-server infinite buffer queueing system with additional servers (assistants) providing help to the main servers when they encounter problems is considered as the model of real-world systems with customers’ self-service. Such systems are widely used in many areas of human activity. An arrival flow is assumed to be the novel essential generalization of the known Markov Arrival Process (MAP) to the case of the dynamic dependence of the parameters of the MAP on the rating of the system. The rating is the process defined at any moment by the quality of service of previously arrived customers. The possibilities of a customers immediate departure from the system at the entrance to the system and the buffer due to impatience are taken into account. The system is analyzed via the use of the results for multi-dimensional Markov chains with level-dependent behavior. The transparent stability condition is derived, as well as the expressions for the key performance indicators of the system in terms of the stationary probabilities of the Markov chain. Numerical results are provided

Service Performance Analysis and Improvement for a Ticket Queue with Balking Customers

Queueing systems managed by ticket technology are widely used in service industries as well as government offices. Upon arriving at a ticket queue, each customer is issued a numbered ticket. The number currently being served is displayed. An arriving customer balks if the difference between his ticket number and the displayed number exceeds his patience level. We propose a Markov chain model of a ticket queue and develop effective evaluation tools. These tools can help management quantify the service level and identify the performance gap between the ticket queue and the conventional physical queue, in which a waiting line is formed. We gain insights about the ways customer service is affected by information loss in the ticket queue. In particular, we show that ticket and physical queues have significantly different balking probabilities when customer patience is low and the system traffic is heavy. We also propose an improvement to the ticket queue that provides each customer with his expected waiting time conditioned on his observed number difference, which is shown to raise the performance of the ticket queue to that of the physical queue.ticket queue, service systems, Markov queues, quasi-birth-and-death processes, heuristics, service improvement

GOOD THINGS COME TO THOSE WHO (PEACEFULLY) WAIT: TOWARD A THEORY OF PATIENCE

Patience is among the most common colloquially known virtues, and yet its empirical attention is among the smallest of all virtues. In this dissertation, I focused on the conscientiousness-based virtue of patience in terms of theory and intervention. In my first study, I examined the effects of a preliminary intervention workbook designed to promote patience. In my second study, I examined a number of correlates informed by patience literature as potential antecedents, mechanisms, and outcomes of patience and, using structural equation modeling, present a theory of patience. Finally, in my third study, I beta tested the patience intervention workbook along with outcome measures posited in my proposed theory of patience in order to examine this theory under experimental and longitudinal design. In Study 1, the patience workbook did indeed produce higher patience outcomes at post-test relative to the control condition but was not significantly different from a positivity workbook condition. Participants in the patience workbook condition also improved in trait self-control, trait forgivingness, and trait negativity. In Study 2, familiarity with an identified stressor and perceived stress related to that stressor predicted state patience for that stressor, consistent with an ego-depletion model of patience. Additionally, patience predicted mental (resilience, anxiety, satisfaction with life, depression, positive affect, and negative affect), physical, relational (communicative competence and perceived social support), and spiritual (spiritual attitudes and involvement) health outcomes. Study 3 replicated the support for an ego-depletion model of patience, and those in the patience intervention workbook improved in trait and state patience, anxiety, and depression, extending and partially supporting the outcomes found in Study 2. The present studies support the use of a workbook intervention to promote patience and additional virtue and mental health outcomes. Implications of these results and future research directions are discussed

Níveis de serviço e simulação computacional: um estudo de caso da influência de fatores no tempo de atendimento em uma praça de pedágio rodoviário.

A capacidade e o nível de serviço das instalações de pedágio ainda não foram formalmente abordados no Highway Capacity Manual, que reconhece e afirma que deve ser dada especial atenção às características únicas, restrições e atrasos causados por estas instalações de cobrança. Essa pesquisa buscou elucidar os seguintes questionamentos: como fatores humanos e operacionais influenciam o tempo de atendimento manual em praças de pedágio? E qual a relação com os níveis de serviço proporcionados pela empresa? Teve por objetivo avaliar os níveis de serviço oferecidos em uma praça de pedágio rodoviário por meio da simulação computacional, testando a influência de fatores na capacidade de atendimento manual. Para alcançar esse objetivo foi realizado um estudo de caso em uma praça de pedágio localizada no estado de Minas Gerais. A coleta de dados, realizada por intermédio de vídeos, documentos e visitas ao local, forneceu informações como a categoria do veículo, a forma de pagamento, o turno de trabalho, dia da semana e sexo do arrecadador; também forneceu o volume de veículos que passaram pela praça e sua composição. O trabalho pode ser dividido em duas etapas: a primeira buscando analisar a influência de fatores no tempo de atendimento por meio de análise estatística e DOE e a segunda etapa realizada por meio da modelagem e simulação, visando determinar o nível de serviço oferecido pela concessionária aos seus clientes. As conclusões principais da análise dos dados coletados mostram que os fatores Categoria do veículo, Forma de pagamento e Sexo do arrecadador são os que têm maior influência no tempo de atendimento, sendo o fator Categoria o mais impactante, aumentando significativamente o tempo de atendimento. A simulação computacional possibilitou avaliar o nível de serviço atual da praça de pedágio e também cenários diversos. A praça atualmente opera com um nível de serviço D em dias normais de funcionamento, no qual um veículo permanece no sistema entre 45 e 60 segundos. Entretanto, em feriados esse nível de serviço cai para E no turno da madrugada e para o F nos turnos da manhã e tarde. A pesquisa mostrou que existem alternativas e melhorias que podem ser aplicadas no ato de arrecadação manual da praça de pedágio estudada

Stability Problems for Stochastic Models: Theory and Applications II

Most papers published in this Special Issue of Mathematics are written by the participants of the XXXVI International Seminar on Stability Problems for Stochastic Models, 21­25 June, 2021, Petrozavodsk, Russia. The scope of the seminar embraces the following topics: Limit theorems and stability problems; Asymptotic theory of stochastic processes; Stable distributions and processes; Asymptotic statistics; Discrete probability models; Characterization of probability distributions; Insurance and financial mathematics; Applied statistics; Queueing theory; and other fields. This Special Issue contains 12 papers by specialists who represent 6 countries: Belarus, France, Hungary, India, Italy, and Russia

Management queues performances in postal traffic

U doktorskoj disertaciji rešavaju se sledeći problemi: problem opisivanja sistema masovnog opsluživanja kada teorija masovnog opsluživanja nailazi na ograničenja primene, problem predviđanja vremena čekanja, problem modelovanja odnosa na tržištu ekspres usluga kao izvora uticaja na redove čekanja, problem upravljanja brojem aktivnih kanala sistema masovnog opsluživanja i problem uticaja na subjektivno vreme čekanja. Primenom elemenata veštačke inteligencije i statističkih metoda razvijen je model za predviđanje parametra vremena čekanja u realnom vremenu pri jedinicama poštanske mreže za pružanje usluga korisnicima.The dissertation provides answers to the following issues: the problem of describing the queueing system when the queueing theory encounters limitations in its use, predicting the waiting time, the problem of modeling relations in the market of express services as a source of influence on the queues, managing the number of active channels in the queueing systems and the impact on subjective waiting time. Through application of artificial intelligence and statistical methods, a model has been developed which in real time predicts the parameters of waiting time at the units of postal network that provide service to customers