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Permanência e evas?o na educa??o técnica de nível médio em Minas Gerais
Dore, Rosemary;Lüscher, Ana Zuleima;
Cadernos de Pesquisa , 2011, DOI: 10.1590/S0100-15742011000300007
Abstract: this article focuses on some considerations concerning the multiple contexts of carrying out the research vocation education and school dropout in minas gerais. amongst its main objectives, this inquiry tries to identify the factors that contribute to the student's persistence (continuation) or dropout in vocational and technical education in the state of minas gerais. to begin with, it discusses some analysis of the conditions which favours student's persistence or dropout. next is examined the context of brazilian educational policies and the relationship between basic education and vocational education. it also points out the scarcity of theoretical and empirical information on the question. to illustrate the problem of the school dropout, it gives some empirical data related to a program of vocational education in minas gerais, and briefly analyses them. finally, it presents some preliminary conclusions.
On a Processor Sharing Queue That Models Balking  [PDF]
Qiang Zhen,Johan S. H. van Leeuwaarden,Charles Knessl
Mathematics , 2009, DOI: 10.1007/s00186-010-0328-z
Abstract: We consider the processor sharing $M/M/1$-PS queue which also models balking. A customer that arrives and sees $n$ others in the system "balks" (i.e., decides not to enter) with probability $1-b_n$. If $b_n$ is inversely proportional to $n+1$, we obtain explicit expressions for a tagged customer's sojourn time distribution. We consider both the conditional distribution, conditioned on the number of other customers present when the tagged customer arrives, as well as the unconditional distribution. We then evaluate the results in various asymptotic limits. These include large time (tail behavior) and/or large $n$, lightly loaded systems where the arrival rate $\lambda\to 0$, and heavily loaded systems where $\lambda\to\infty$. We find that the asymptotic structure for the problem with balking is much different from the standard $M/M/1$-PS queue. We also discuss a perturbation method for deriving the asymptotics, which should apply to more general balking functions.
Balking and reneging in a vacation queueing model
Madan K. C.
Revista Colombiana de Estadística , 1993,
Abstract: We study a single server queueing system in which arrivals follow a compound Poisson process and the service times of customers have exponential distribution. The system is subject to server vacations occuiring randomly in time and in addition the impatient customers resort to balking and reneging during the server's vacation period. The steady state probability generating functions for the system when the server is available or on vacation have been obtained explicitly as also the average number in the system. Various particular cases of interest have also been derived.
Leishmaniose visceral: estudo de flebotomíneos e infec??o canina em Montes Claros, Minas Gerais
Monteiro, érika Michalsky;Silva, Jo?o Carlos Fran?a da;Costa, Roberto Teodoro da;Costa, Daniela Camargos;Barata, Ricardo Andrade;Paula, Edvá Vieira de;Machado-Coelho, George Luis Lins;Rocha, Marília Fonseca;Fortes-Dias, Consuelo Latorre;Dias, Edelberto Santos;
Revista da Sociedade Brasileira de Medicina Tropical , 2005, DOI: 10.1590/S0037-86822005000200004
Abstract: visceral leishmaniasis in brazil was initially associated with rural areas. however, due to several environmental modifications such as deforestation, urbanization and intense migratory processes, there has been an expansion of endemic areas, leading to urbanization of the disease, mainly in the central and northeastern regions of brazil. in the municipality of montes claros, located in the north of the state of minas gerais, an epidemiological survey on vl was carried out. a canine serological inquiry was carried out in 2002 and an entomological survey, using luminous cdc traps, was performed from september 2002 to august 2003. canine vl prevalence showed an average infection rate of approximately 5%. an estimated 16 species comprised the phlebotomine sand fly fauna, based on a total of 1043 specimens. the predominant species was lutzomyia longipalpis with a rate of 74%, suggesting its participation in the transmission of vl in the municipality of montes claros.
Inhomogeneous CTMC Model of a Call Center with Balking and Abandonment  [PDF]
Maciej Rafal Burak
Computer Science , 2015,
Abstract: This paper considers a nonstationary multiserver queuing model with abandonment and balking for inbound call centers. We present a continuous time Markov chain (CTMC) model which captures the important characteristics of an inbound call center and obtain a numerical solution for its transient state probabilities using uniformization method with steady-state detection. Keywords: call center, transient, Markov processes, numerical methods, uniformization, abandonment, balking
Optimization of Balking and Reneging Queue with Vacation Interruption under -Policy  [PDF]
P. Vijaya Laxmi,V. Goswami,K. Jyothsna
Journal of Optimization , 2013, DOI: 10.1155/2013/683708
Abstract: This paper analyzes a finite buffer multiple working vacations queue with balking, reneging, and vacation interruption under -policy. In the working vacation, a customer is served at a lower rate and at the instants of a service completion; if there are at least customers in the queue, the vacation is interrupted and the server switches to regular busy period otherwise continues the vacation. Using Markov process and recursive technique, we derive the stationary system length distributions at arbitrary epoch. Various performance measures and some special models of the system are presented. Cost analysis is carried out using particle swarm optimization and quadratic fit search method. Finally, some numerical results showing the effect of model parameters on key performance measures of the system are presented. 1. Introduction Performance modeling of queueing systems with balking and reneging has attracted many researchers owing to their wide applications in real life congestion problems such as impatient telephone switchboard customers, hospital emergency rooms handling critical patients and perishable goods storage in inventory systems. Balking and reneging are a common phenomena in queues; as a consequence, the customers either decide not to join the queue or depart after joining the queue without getting service due to impatience. Modeling balking and reneging is worthwhile because one obtains new managerial insights. The lost revenues due to balking and reneging in various industries can be enormous. While making decision for the number of servers needed in the service system to meet time-varying demand, the balking and reneging probabilities can be used to estimate the amount of lost business in more practical consideration for the managers as given in Liao [1]. Impatience is the most prominent characteristic as individuals always feel anxious and impatient during waiting for service in real life. The customer's impatient acts should be involved in the study of queueing system to model real situations exactly. Intermittent operation of a service can be economically appealing whenever full time service would result in significant server idle time or would preclude the use of the server in some other productive capacity. On the other hand, having the server inoperative for periods of time may increase the probability of customer losses due to balking and reneging. An queue with customers balking and reneging has been discussed in Haight [2] and Haight [3], respectively. The combined impact of balking and reneging with finite capacity in an queue has
Equilibrium balking strategies in the single server Markovian queue with catastrophes  [PDF]
Olga Boudali,Antonis Economou
Mathematics , 2011,
Abstract: We consider a Markovian queue subject to Poisson generated catastrophes. Whenever a catastrophe occurs, all customers are forced to abandon the system, the server is rendered inoperative and an exponential repair time is set on. We assume that the arriving customers decide whether to join the system or balk, based on a natural reward-cost structure. We study the balking behavior of the customers and derive the corresponding Nash equilibrium strategies.
Melophagus ovinus e Trypanosoma (Megatrypanum) melophagium em ovinos no Estado de Minas Gerais, Brasil
Costa, José Oswaldo;Lima, Walter dos Santos;Leite, Antonio César Rios;Guimar?es, Marcos Pezzi;Torres, Liléia Diotaiuti;
Memórias do Instituto Oswaldo Cruz , 1983, DOI: 10.1590/S0074-02761983000100012
Abstract: melophagus ovinus is identified for the first time in minas gerais state and trypanosoma (megatrypanum) melophagium in brazil.
Pothea furtadoi sp. nov. (Hemiptera, Heteroptera, Reduviidae, Ectrichodiinae) de Mato Grosso e Minas Gerais, Brasil
Gil-Santana, Hélcio R.;Costa, Luiz A. A.;
Revista Brasileira de Zoologia , 2005, DOI: 10.1590/S0101-81752005000200014
Abstract: a new species of the genus pothea amyot & serville, 1843, from mato grosso and minas gerais, is described and illustrated.
Equilibrium balking strategies for a clearing queueing system in alternating environment  [PDF]
Antonis Economou,Athanasia Manou
Mathematics , 2011,
Abstract: We consider a Markovian clearing queueing system, where the customers are accumulated according to a Poisson arrival process and the server removes all present customers at the completion epochs of exponential service cycles. This system may represent the visits of a transportation facility with unlimited capacity at a certain station. The system evolves in an alternating environment that influences the arrival and the service rates. We assume that the arriving customers decide whether to join the system or balk, based on a natural linear reward-cost structure. We study the balking behavior of the customers and derive the corresponding Nash equilibrium strategies under various levels of information.
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