Hazard Rate Research Papers - Academia.edu (original) (raw)

In view of their importance and usefulness in reliability theory and probability distributions, several generalizations of the inverse Gaussian distribution and the Krtzel function are investigated in recent years. This has motivated the... more

In view of their importance and usefulness in reliability theory and probability distributions, several generalizations of the inverse Gaussian distribution and the Krtzel function are investigated in recent years. This has motivated the authors to introduce and study a new generalization of the inverse Gaussian distribution and the Krtzel function associated with a product of a Bessel function of the third kind )(zKQ and a Z - Fox-Wright generalized hyper geometric function introduced in this paper. The introduced function turns out to be a unified gamma-type function. Its incomplete forms are also discussed. Several properties of this gamma-type function are obtained. By means of this generalized function, we introduce a generalization of inverse Gaussian distribution, which is useful in reliability analysis, diffusion processes, and radio techniques etc. The inverse Gaussian distribution thus introduced also provides a generalization of the Krtzel function. Some basic statistical...

Le NDYP (The New Deal for Young People) est le principal programme d’aide sociale au travail au Royaume-Uni destiné aux chômeurs âgés de 18 à 24 ans recevant une allocation de demandeur d’emploi (JSA) pendant au moins six mois. L’objectif... more

Le NDYP (The New Deal for Young People) est le principal programme d’aide sociale au travail au Royaume-Uni destiné aux chômeurs âgés de 18 à 24 ans recevant une allocation de demandeur d’emploi (JSA) pendant au moins six mois.
L’objectif naturel du programme est d’améliorer l’employabilité à la fois extensive (trouver un emploi) et intensive (emploi durable de haute qualité), tout en acquérant des compétences et de la motivation.
Les principales questions auxquelles répond ce document sont les suivantes : « La politique améliore-t-elle réellement les perspectives d’emploi des jeunes ? » et « Les effets de la politique perdurent-ils sur différentes cohortes ? ».

We obtain a heavy traffic limit for the GI/M/n + GI queue, which includes the entire patience time distribution. Our main approach is to scale the hazard rate function of the patience time distribution in such a way that our resulting... more

We obtain a heavy traffic limit for the GI/M/n + GI queue, which includes the entire patience time distribution. Our main approach is to scale the hazard rate function of the patience time distribution in such a way that our resulting diffusion approximation contains the entire hazard rate function. We then show through numerical studies that for various performance measures, our approximations tend to outperform those commonly used in practice. The robustness of our results is also demonstrated by applying them to solving constraint satisfaction problems arising in the context of telephone call centers.

We study a single-server queue, operating under the first-in-first-out (FIFO) service discipline, in which each customer independently abandons the queue if his service has not begun within a generally distributed amount of time. Under... more

We study a single-server queue, operating under the first-in-first-out (FIFO) service discipline, in which each customer independently abandons the queue if his service has not begun within a generally distributed amount of time. Under some mild conditions on the abandonment distribution, we identify a limiting heavy-traffic regime in which the resulting diffusion approximation for both the offered waiting time process (the process that tracks the amount of time an infinitely patient arriving customer would wait for service) and the queue-length process contain the entire abandonment distribution. To use a continuous mapping approach to establish our weak convergence results, we additionally develop existence, uniqueness, and continuity results for nonlinear generalized regulator mappings that are of independent interest. We further perform a simulation study to evaluate the quality of the proposed approximations for the steady-state mean queue length and the steady-state probabilit...

We obtain a heavy-traffic limit for the GI/M/n + GI queue which includes the entire aban-donment distribution. Our main approach is to scale the hazard rate function in an appropriate way such that our resulting diffusion approximation... more

We obtain a heavy-traffic limit for the GI/M/n + GI queue which includes the entire aban-donment distribution. Our main approach is to scale the hazard rate function in an appropriate way such that our resulting diffusion approximation contains the entire hazard rate function. We ...

IZA DP No. 11270 JANUARY 2018 If Not Now, When? The Timing of Childbirth and Labour Market Outcomes* We study the effect of childbirth and its timing on female labour market outcomes in Italy. The impact on yearly labour earnings and... more

IZA DP No. 11270 JANUARY 2018 If Not Now, When? The Timing of Childbirth and Labour Market Outcomes* We study the effect of childbirth and its timing on female labour market outcomes in Italy. The impact on yearly labour earnings and participation is traced up to 21 years since school completion by estimating a factor analytic model with dynamic selection into treatments. We find that childbearing, especially the first delivery, negatively affects female labour supply. Women having their first child soon after school completion are able to catch up with childless women only after 12–15 years. The timing matters, with minimal negative consequences observed if the first child is delayed up to 7–9 years after exiting formal

Event-time or continuous-time statistical approaches have been applied throughout the biostatistical literature and have led to numerous scientific advances. However, these techniques have traditionally relied on knowing failure times.... more

Event-time or continuous-time statistical approaches have been applied throughout the biostatistical literature and have led to numerous scientific advances. However, these techniques have traditionally relied on knowing failure times. This has limited application of these analyses, particularly, within the ecological field where fates of marked animals may be unknown. To address these limitations, we developed an integrated approach within a Bayesian framework to estimate hazard rates in the face of unknown fates. We combine failure/survival times from individuals whose fates are known and times of which are interval-censored with information from those whose fates are unknown, and model the process of detecting animals with unknown fates. This provides the foundation for our integrated model and permits necessary parameter estimation. We provide the Bayesian model, its derivation, and use simulation techniques to investigate the properties and performance of our approach under sev...

In this case study, groundwater/surface water modeling was used to determine efficacy of stabilization in place with hydrologic isolation for remediation of mercury contaminated areas in the Upper East Fork Poplar Creek (UEFPC) Watershed... more

In this case study, groundwater/surface water modeling was used to determine efficacy of stabilization in place with hydrologic isolation for remediation of mercury contaminated areas in the Upper East Fork Poplar Creek (UEFPC) Watershed in Oak Ridge, TN. The modeling simulates the potential for mercury in soil to contaminate groundwater above industrial use risk standards and to contribute to surface water contamination. The modeling approach is unique in that it couples watershed hydrology with the total mercury transport and provides a tool for analysis of changes in mercury load related to daily precipitation, evaporation, and runoff from storms. The model also allows for simulation of colloidal transport of total mercury in surface water. Previous models for the watershed only simulated average yearly conditions and dissolved concentrations that are not sufficient for predicting mercury flux under variable flow conditions that control colloidal transport of mercury in the water...

Die ZBW räumt Ihnen als Nutzerin/Nutzer das unentgeltliche, räumlich unbeschränkte und zeitlich auf die Dauer des Schutzrechts beschränkte einfache Recht ein, das ausgewählte Werk im Rahmen der unter

This case focuses on the application of queueing theory to urban planning. It would be suitable for either an undergraduate or graduate course in queueing theory or urban operations research. The case examines the problem of patrol car... more

This case focuses on the application of queueing theory to urban planning. It would be suitable for either an undergraduate or graduate course in queueing theory or urban operations research. The case examines the problem of patrol car allocation. The students are shown the weakness of the so-called hazard rate allocation that is common police practice. This allocation is based solely on call-for-service (arrival) rates. The case also illustrates the weakness of a focus solely on server workload (utilization). Armed with an appreciation of queueing effects, the students are then asked to explore the vast set of possible patrol car allocations. The choice of the “best” or even a “good” allocation depends on a subjective assessment of the important criteria, which usually involve consideration for police response times and officer workloads.

This paper is focused on searching for the suitable discount rate to be applied to the valuation of a project related to forests in the USA, e.g., a recreational area inside a national park. To do this, we propose a new model based on... more

This paper is focused on searching for the suitable discount rate to be applied to the valuation of a project related to forests in the USA, e.g., a recreational area inside a national park. To do this, we propose a new model based on hazard rate concepts, i.e., based on the risk that waiting time implies. More specifically, we derive the discount function whose instantaneous discount rate is the hazard rate of the system supporting the investment. We determine the rate of failure corresponding to different partition criteria of the whole system; in our case, we can use the information on forest fires caused in different ways, in different states or in different types of forest surfaces. After showing independence between the forest fires by states and causes, we derive a specific discount function for each cause which can be applied to every state or set of states which agree to fight against a concrete cause of forest fire. Additionally, we obtain a unique discount function by wei...

Survival mixture model of three different distributions was proposed. The model consists of a mixture of Exponential, Gamma and Weibull distributions. Simulated data was employed to investigate the performance of the model by considering... more

Survival mixture model of three different distributions was proposed. The model consists of a mixture of Exponential, Gamma and Weibull distributions. Simulated data was employed to investigate the performance of the model by considering three different censoring percentages and two sets of mixing probabilities in ascending order and descending order. The simulated data were used to estimate the maximum likelihood estimators of the model by employing Expectation Maximization (EM). Hazard functions corresponding to the censoring percentages were investigated graphically. Parameters of the proposed model were estimated and were all close the values used in generating the data. Simulation was repeated 300 times and the mean square error (MSE) and root mean square error (RMSE) were estimated to assess the consistency and stability of the model. The simulated data used to compare the effect of different censoring percentages revealed that the model performed much better with small percen...