Analysis of an unreliable MX/G1G2/1/repeated service queue with delayed repair under randomized vacation policy

Abstract

In this article we consider an unreliable M^X/G/1 queue with two types of general heterogeneous service and optional repeated service subject to server’s break down and delayed repair under randomized vacation policy. We assume that customer arrive to the system according to a compound Poisson process. The server provides two types of general heterogeneous service and a customer can choose either type of service before its service start. After the completion of either type of service, the customer has the further option to repeat the same type of service once again. While the server is working with any types of service or repeated service, it may breakdown at any instant. Further the concept of randomized vacation is also introduced. For this model, we first derive the joint distribution of state of the server and queue size by considering both elapsed and remaining time, which is one of the objective of this article. Next, we derive Laplace Stieltjes transform of busy period distribution. Finally, we obtain some important performance measure and reliability indices of this model.     

Relative income and fertility

The present study examines the relationship between relative income (i.e., actual income in relation to the expected income of one’s socioeconomic group) and fertility, using data collected by the 1967-1968Canadian Family Growth Study (Balakrishnan et al., 1975). We broaden the tests of relative income beyond cumulative fertility to spacing behavior and then examine some of the assumptions included in the relative income model of fertility. Results of the tests, in brief, are as follows: (a) Relative income is found to be more closely related to spacing than to cumulative fertility; and (b) the relationship between relative income and fertility is strongest among those couples who plan their life ahead and have a high level of education and occupation, and when temporal alignment is brought between the measures of relative income and fertility. For the relative income model to receive confirmation, it was specified that the following hypotheses must be confirmed: (a) that fertility behavior would vary positively with relative income but the fertility norm would show no relationship with relative income; and (b) that consumption norms and behavior would show no relationship with relative income. The outcome of these tests are in the expected direction, giving support to the relative income model. In addition, there is some evidence of predictive capability of the relative income model for correlative behavior.     

A new approach to motivation: Four-drive model

ABSTRACT

This article presents a new approach to the field of motivation. To start, it reviews the previously available literature in the field and analyzes some of the more popular theories and finds the gaps. A new model is put forward, which aims to cover the relevant parameters—as well as to plug the identified gaps. The model proposes four types of drives—sensual, material, emotional, and spiritual. A quantitative study was done to validate the proposed theory and to have a better understanding in identifying the socioeconomic parameters that are significant in predicting which drive is likely to dominate in a person. Using the proposed theory and the results from the quantitative analysis, a model for motivation is proposed. This research is part of an ongoing research effort to test, validate, and generalize the proposed model.     

Untransformed first observation problem in regression model with moving average process

This paper shows the impact of underestimation of variance of an estima-tor when first observation is left untransformed to simplify the computational procedure. In fact, the bias of the variance is not diminishing even for large sample size for the model considered. By partitioning the covariance matrix into two parts, this paper explains why least square estimator with untrans-formed first observation shows such a consequence. To demonstrate this, an exact GLS estimator is developed by modifying an approximate estimator. Nonetheless, the computational simplicity remains same.     

Multidimensional Poverty in Mountainous Regions: Shan and Chin in Myanmar

Poverty is complex and multidimensional. People living in mountainous regions are vulnerable and more likely to experience multiple deprivation. However, few studies have addressed multidimensional poverty in mountainous regions. Using data from 4290 households of poverty and vulnerability assessment survey and the Alkire–Foster methodology, this paper estimate and decompose multidimensional poverty in the states of Shan and Chin in Myanmar. The multidimensional poverty is measured in five dimensions and a set of twelve indicators. Nearly half of the population in Shan and three-quarters in Chin were multidimensionally poor. The average intensity of poverty was 44% in Chin and 38% in Shan. The multidimensional poverty index was 0.33 in Chin and 0.19 in Shan. The level of multidimensional poverty in Chin was similar to that in of Sub-Saharan Africa. In Chin, 60% of the population was both multidimensionally poor and consumption poor, but in Shan, it was 20%. About 28% of the population in Shan and 15% in Chin were multidimensionally poor but not consumption poor. Deprivation in education accounts for one-third of the multidimensional poverty in Shan; while deprivation in health accounts for one-third of the multidimensional poverty in Chin. A higher proportion of multidimensionally poor had experienced shocks such as the death of a household member, agricultural loss, or death of livestock compared to the multidimensional non-poor. Multidimensional poverty was significantly higher for rural household, households with lower educational attainment, consumption poor and among those who lived in Chin. Poverty reduction programs require a holistic understanding of poverty and its different dimensions as well as the main contributing factors for effective planning and program implementation. Geographical targeting of poverty reduction program and larger investment in food, health, water, energy and education can reduce the extent of multidimensional poverty in Shan and Chin.     

Pregnancy termination intervals in a rural area of Bangladesh

Pregnancy termination intervals, i.e., live birth to live birth (LB-LB), live birth to fetal loss (LB-FL), and fetal loss to live birth (FL-LB), are analyzed prospectively between 1966 and 1970 in a rural population (117,000) of Bangladesh. Results indicate that the mean LB-LB interval was almost 30 months, the LB-FL interval 27 months, and the FL-LB interval 18 months. In addition, postpartum amenorrhea was estimated to be about 13-14 months, and the time added by a fetal loss toa LB-LB interval about 15 months. No relationship was found between LB-LB intervals and the number of living or dead children.     

Computing an $$L_1$$ shortest path among splinegonal obstacles in the plane

Journal of Combinatorial Optimization - We reduce the problem of computing an $$L_1$$ shortest path between two given points s and t in the given splinegonal domain $$\mathcal {S}$$ to the problem...