Optimum reliability acceptance sampling plans under progressive type-I interval censoring with random removal using a cost model

A reliability acceptance sampling plan (RASP) is a variable sampling plan, which is used for lot sentencing based on the lifetime of the product under consideration. If a good lot is rejected then there is a loss of sales, whereas if a bad lot is accepted then the post sale cost increases and the brand image of the product is affected. Since cost is an important decision-making factor, adopting an economically optimal RASP is indispensable. This work considers the determination of an asymptotically optimum RASP under progressive type-I interval censoring scheme with random removal (PICR-I). We formulate a decision model for lot sentencing and a cost function is proposed that quantifies the losses. The cost function includes the cost of conducting the life test and warranty cost when the lot is accepted, and the cost of batch disposition when it is rejected. The asymptotically optimal RASP is obtained by minimizing the Bayes risk in a set of decision rules based on the maximum likelihood estimator of the mean lifetime of the items in the lot. For numerical illustration, we consider that lifetimes follow exponential or Weibull distributions.     

Infrastructures of Sociality: How Disadvantaged Students Navigate Inequity at the University1

Through an ethnography of college life in India, I examine the role of social ties in navigating the inequities of university life. I analyze the socialities of sharing knowledge and resources among disadvantaged students, which I call “infrastructures of sociality.” “Infrastructure” designates here two things: first, the role of the university's infrastructure—its physical spaces and organizational routines—in enabling social ties; and second, the fact that these social ties literally function as infrastructure, in that they make university life possible for disadvantaged students, especially in the context of institutional neglect. I therefore advance Bourdieusian scholarship that views social ties among disadvantaged students as merely lacking in social capital, arguing instead that these ties constitute a form of non-dominant social capital that is analytically distinct and powerful in its own right. Yet, I suggest that these social ties are a double-edged sword: while the intensive mutual aid of disadvantaged students makes university participation possible, it nonetheless rests on exclusion from more privileged social groups. Thus, despite mitigating exclusion from the university, infrastructures of sociality also inadvertently participate in the reproduction of inequality, by reinforcing exclusion from the elite cultural and social resources circulating among privileged students.