The effects of working hours on health were examined taking psychological job strain into account. White-collar workers employed at the main office of a Japanese manufacturing company provided data for analysis done in 1997. The eligible subjects were 286 workers aged 20-39. Causal relationships between working hours, health, and psychological job strain were examined by covariance structure an...

Nevi are a main risk factor for malignant melanoma, and most nevi develop in childhood. This study examined the relationship between vacations and nevi in 681 White children born in 1998 who were lifetime residents of Colorado. Vacation histories were assessed through telephone interviews of parents, whereas nevus and phenotypic characteristics were assessed through skin exams at age 7. Multipl...

This paper considers the reliability of an M/G/1 queue with multiple adaptive vacations in which the arriving customers enter the system with probability p (0<p≤1) during vacations. Through appropriate assumptions, the model is studied by the total probability decomposition technique and the tool of Laplace transform. Some reliability indices are studied. Moreover, we give some numerical exampl...

As a generalization of classic queueing models with vacations,the working vacation queues were introduced in 2002, where the server serves customers at a lower rate rather than completely stopping service during the vacation period. This type of vacation models can be applied in performance evaluation of optical communication networks, production and service systems, and other fields. In recent...

This paper treats two-threshold policies for an M/G/1 queue with two types of generally distributed random vacations: type 1 (long) and type 2 (short) vacations. Upon returning from a vacation, the server observes the queue length. If this is less than the lower threshold, the server takes a type 1 vacation; if it is between the two thresholds, the server takes a type 2 vacation; and if it is a...