Stochastic comparisons of order statistics,with applications in relibility

This paper reviews recent developments in the stochastic comparison of order statistics. The results discussed are basically: (l) Stochastic comparisons of linear combinations of order statistics from distributions F and G where G^?1 F is convex or starshaped. (2) Stochastic comparisons of individual order statistics and of vectors of order statistics from underlying heterogeneous distributions by the use of majorization and Schur function theory. (3) Stochastic comparison of random processes. Applications to reliability problems are presented illustrating the use and value of the theoretical results described     

No city for migrant women: construction workers’ experiences of exclusion from urban governance and discrimination in labour markets in Ahmedabad

ABSTRACT

Ahmedabad, Gujarat, is one of the fastest growing cities in the world, and a reflection of India’s story of exclusionary economic growth. This article focuses on research carried out with women construction workers with the help of a migrant construction workers’ union in Ahmedabad. It describes the method used by women members of the union to make visible their experiences as migrants in the city – with men, local authorities, and employers – to highlight the additional burdens that they bear due to a negligent state and industry, advocate for better working and living conditions, and raise consciousness of gender inequalities that need to be integrated into the demands of the workers’ union.     

Causal Linkages in Supply Chain Management: An Exploratory Study of North American Manufacturing Firms

In this paper we investigate the key causal linkages in supply chain management. We propose a conceptual framework and test this framework on data from 215 North American manufacturing firms using structural equation modeling techniques. Three major research issues are addressed in this study: Do sourcing decisions affect the degree to which firms achieve manufacturing goals of cost, flexibility, dependability, and quality? Does the degree of manufacturing goal achievement lead to higher customer responsiveness? Does the degree of manufacturing goal achievement lead to higher internal manufacturing performance? The study examines the relationship among sourcing decisions, manufacturing goals, customer responsiveness, and manufacturing performance. The results support the notion that an integrated supply chain involves aligning sourcing decisions to achieve manufacturing goals that are set to respond favorably to the needs of customers.     

The Differential and Contingent Impact of Concurrency on New Product Development Project Performance: A Holistic Examination*

This article comprehensively examines how the four facets of new product development (NPD) concurrency, consisting of process and product concurrency groupings, influence NPD project performance under the five contextual conditions of (i) location of product in family stream, (ii) project size, (iii) stage in the product life cycle, (iv) innovativeness of the product, and (v) predictability of market demand. Using data from a large sample of NPD projects in multiple industries, there is support for this hypothesized four‐faceted structure of concurrency, consisting of process and product concurrency groupings, thereby contributing new knowledge to the concurrency literature. All four facets of concurrency display a contingent impact on NPD project performance, even though individual effects vary according to the specific contextual variable under consideration. In particular, the process concurrency facet of dynamic iterative routines was universally effective across all five contextual variables, while the product concurrency facet of cross‐functional coordination was effective in significantly influencing at least one NPD project measure. This article also reports similar, but less strong, contingency patterns, with respect to the process concurrency facet of the implementation of downstream coordination and the product concurrency facet of the use of computer‐based integrated design tools. Theoretical and practical implications of our results are also offered.     

Nonparametric Bayes estimation in repair models

Consider a sequence of dependent random variables _X1,_X2,…,_Xn$X_1,X_2,\dots ,X_n$, where _X1$X_1$ has distribution F (or probability measure P  ), and the distribution of _Xi+1$X_{i+1}$ given _X1,…,_Xi$X_1,\dots ,X_i$ and other covariates and environmental factors depends on F   and the previous data, i=1,…,n-1$i=1,\dots ,n-1$. General repair models give rise to such random variables as the failure times of an item subject to repair. There exist nonparametric non-Bayes methods of estimating F in the literature, for instance, Whitaker and Samaniego [1989. Estimating the reliability of systems subject to imperfect repair. J. Amer. Statist. Assoc. 84, 301–309], Hollander et al. [1992. Nonparametric methods for imperfect repair models. Ann. Statist. 20, 879–896] and Dorado et al. [1997. Nonparametric estimation for a general repair model. Ann. Statist. 25, 1140–1160], etc. Typically these methods apply only to special repair models and also require repair data on N independent items until exactly only one item is left awaiting a “perfect repair”.     

Internal and External Integration for Product Development: The Contingency Effects of Uncertainty,Equivocality, and Platform Strategy

Effective product development requires firms to unify internal and external participants. As companies attempt to create this integrated environment, two important questions emerge. Does a high level of internal integration lead to a higher level of external integration? In the context of product development, this study considers whether internal integration in the form of concurrent engineering practices affects the level of external integration as manifested by customer integration, supplier product integration, and supplier process integration. External integration, in turn, may influence competitive capabilities, namely product innovation performance and quality performance. Second, using contingency theory, do certain contextual variables moderate the linkages between integration strategy (external and internal) and performance? Specifically, this study considers whether uncertainty, equivocality, and platform development strategy change the relationships among internal integration, external integration, and competitive capabilities. Data collected from 244 manufacturing firms across several industries were used to test these research questions. The results indicate that both internal and external integration positively influence product innovation and quality and ultimately, profitability. With respect to contingency effects, the results indicate that equivocality moderates the relationships between integration and performance.