The departure process of a quorum queueing system

AbstractWe study in this paper the departure process of a bulk service queueing system. The server operates under a minimum batch size strategy. We characterize the departure process through the distribution of the interdeparture times of batches and of customers, the distribution of the number of customers in a batch, and the coefficient of correlation between the interdeparture time of a batch and the number of customers in the batch. A numerical illustration is presented

The Mx/G/1 Queue with Unreliable Server, Delayed Repairs, and Bernoulli Vacation Schedule under T-Policy

In this paper we study a batch arrival queuing system. The server may break down while delivering service. However, repair is not provided immediately, rather it is delayed for a random amount of time. At the end of service, the server may process the next customer if any are available, or may take a vacation to execute some other job. Finally, the server implements the T-policy. We describe for this system an optimal management policy. Numerical examples are provided

Infectious Complications of Contact Lenses: A Review of the Literature

The use of contact lenses is very common, they are prescribed for the correction of refractive errors that cannot be treated by glasses such as aphakia, keratoconus and strong anisometropia, or as alternatives to glasses. Contact lenses can cause serious complications that are not always easy for patients to manage [1]. Infectious complications in contact lens wearers are a real diagnostic and therapeutic emergency. These infections can be bacterial, amoebic (due to wearing contact lenses in swimming pools, rinsing lenses with tap water or saliva), fungal (due to wearing therapeutic, cosmetic or aphakic lenses, diabetes, alcoholism, immunosuppression, corticosteroids). Infectious complications require emergency treatment. The first line of treatment consists of removing the contact lens and sending it, along with the lens case and lens care product, to the laboratory along with corneal samples and appropriate medical treatment. Infectious keratitis related to contact lens wear is serious and can permanently affect the visual prognosis. The prevention requires a fitting under medical supervision and an awareness of the patients with potential risks of infection.The use of contact lenses is very common, they are prescribed for the correction of refractive errors that cannot be treated by glasses such as aphakia, keratoconus and strong anisometropia, or as alternatives to glasses. Contact lenses can cause serious complications that are not always easy for patients to manage [1]. Infectious complications in contact lens wearers are a real diagnostic and therapeutic emergency. These infections can be bacterial, amoebic (due to wearing contact lenses in swimming pools, rinsing lenses with tap water or saliva), fungal (due to wearing therapeutic, cosmetic or aphakic lenses, diabetes, alcoholism, immunosuppression, corticosteroids). Infectious complications require emergency treatment. The first line of treatment consists of removing the contact lens and sending it, along with the lens case and lens care product, to the laboratory along with corneal samples and appropriate medical treatment. Infectious keratitis related to contact lens wear is serious and can permanently affect the visual prognosis. The prevention requires a fitting under medical supervision and an awareness of the patients with potential risks of infection

Optimal Harvesting Effort for Nonlinear Predictive Control Model for a Single Species Fishery

We use nonlinear model predictive control to find the optimal harvesting effort of a renewable resource system with a nonlinear state equation that maximizes a nonlinear profit function. A solution approach is proposed and discussed and satisfactory numerical illustrations are provided

Cry-Based Classification of Healthy and Sick Infants Using Adapted Boosting Mixture Learning Method for Gaussian Mixture Models

We make use of information inside infant’s cry signal in order to identify the infant’s psychological condition. Gaussian mixture models (GMMs) are applied to distinguish between healthy full-term and premature infants, and those with specific medical problems available in our cry database. Cry pattern for each pathological condition is created by using adapted boosting mixture learning (BML) method to estimate mixture model parameters. In the first experiment, test results demonstrate that the introduced adapted BML method for learning of GMMs has a better performance than conventional EM-based reestimation algorithm as a reference system in multipathological classification task. This newborn cry-based diagnostic system (NCDS) extracted Mel-frequency cepstral coefficients (MFCCs) as a feature vector for cry patterns of newborn infants. In binary classification experiment, the system discriminated a test infant’s cry signal into one of two groups, namely, healthy and pathological based on MFCCs. The binary classifier achieved a true positive rate of 80.77% and a true negative rate of 86.96% which show the ability of the system to correctly identify healthy and diseased infants, respectively

Moisture Performance Criteria for UK Dwellings

The new ventilation regulations in England and Wales have introduced performance criteria for the control of mould. The UK Government\'s Building Regulations Research Programme has funded University College London (UCL) to investigate the extent to which these are the most appropriate criteria for thecontrol of mould in UK dwellings. This paper reports on the plans for this study which involve both field and laboratory related work. Some initial early work has already been undertaken and the paper summarises the progress to date. This initial work is based on analysis of data from a national study of England\'s Home Energy Efficiency scheme (Warm Front). Surveys were undertaken of dwellings and households participating in the scheme in five urban areas. Half-hourly living room and main bedroom temperatures and relative humidity measurements were recorded for two to four weeks (in the heating season) in approximately 1600 dwellings. This data is being analysed to investigate the typical relativehumidities that exist in UK dwellings and also any relationship that exists between these levels and the mould growth that was recorded

Impacts of a changed atmosphere: Do increased CO₂ levels decrease human cognitive performance?

Introduction. Climate change has severe consequences for humans, such as health impacts resulting from the burning of fossil fuels, i.e. pollution, and impacts from a changing climate, such as extreme heat and flooding. There is a third, neglected, category that covers impacts from the changed atmosphere per se, i.e. a higher concentration of CO2. Do increased atmospheric CO2 levels influence human cognition negatively? Method. We carried out a rapid evidence assessment. Identified keywords were searched for in title, abstract, and keywords in Scopus and Web of Science. Results were imported into the systematic review software EPPI-Reviewer, and screened according to prespecified criteria. Results Five journal articles were retained after screening. The level of reported details did not allow a meta-analysis; instead, results were descriptively interpreted. All studies took place in environmental chambers in which pure CO2 was inserted to reach levels between 500 ppm and 5000 ppm. Two studies did not find any effect of CO2 on performance, but three studies found that cognitive performance decreased under higher CO2 concentrations. Conclusions. The outcome that human performance might decrease under higher CO2 is already in itself alarming but would have wide-reaching implications on energy use, e.g. of heating and ventilation systems