Gut geruht?

Schlafst?rungen vorbeugen - Oft sind Schlafst?rungen Bestandteil psychischer, organischer oder neurologisch degenerativer Erkrankungen. Sie k?nnen aber auch die Folge falschen Verhaltens oder ungemessener Schlafbedingungen sein. Also: Was f?rdert gesunden Schlaf, was behindert ihn?     

Distributions slanted to the right

We solve Problem 234 in Statistica Neerlandica by introducing the concept of slantedness. Distributions with a decreasing Lebesgue density are slanted to the right. This is no longer true for distributions on a lattice with decreasing density. Both kinds of distributions have positive central odd moments.     

Mapping the benefits and costs associated with process innovation: The case of RFID adoption

The successful implementation of any innovation requires an understanding of its benefits and costs. This study examines the changes in the magnitude of costs and benefits associated with technology process innovation adoption as the innovation diffuses across different industries. Using RFID as an exemplar technology, the study shows that the magnitude of benefits and costs associated with technological process innovation adoption within different industries varies as technology diffuses beyond early adopters to the early majority. During the early stages of technology evolution, the development cost, the cost of capital, ethical costs and simple direct implementation costs (in the form of the cost of tags) predominate. As a dominant design emerges the profile of costs changes with the emphasis on initiation costs, more holistic direct implementation costs and indirect implementation costs. A similar change in the emphasis of benefits is observed, with a shift from direct to indirect benefits being noticeable as the technology moves from early adopters to early majority adopters. Our findings help to explain the difficulties in consistently measuring innovation outcomes observed in the innovation implementation literature, and emphasize the need to take into consideration the stage of technology development as a significant factor that influences the realised outcomes from innovation implementation.     

A solution to log of dependent variables with negative observations

Journal of Productivity Analysis - Negative observations pose a problem in econometric models that apply log-transformation to the data. We propose a simple yet effective solution to this problem...     

基于航空运输的应急物资配送网络优化研究

近年来突发事件的频发给我国带来了重大的生命财产损失,应急物资配送网络的合理构建是提高我国突发事件应急处置能力的重要途径之一.提出一个抗风险能力强、反应速度快、成本节约的基于航空系统的应急物资配送网络目标规划模型,优化应急物资配送中心布局以及应急配送网络的组织形式,并选取全国100个通用机场为例进行实证分析.研究结果表明,最佳的应急物资航空配送网络是以长春、乌鲁木齐、济南、成都、南昌为配送点的中心辐射式网络,且该网络布局形式的投入成本随应急反应时间的缩小而大幅上升.     

On Bayesian optimum allocation in some two phase sampling problems

Summary For estimating certain parametric functions, we consider the problem of allocatingN _i, the size of the sample from theith population,i=1,2,...,k, at the second phase of sampling of a two phase sampling procedure, given that we taken _i observations from the population at the first phase. We consider that the observations from theith population follow the exponential distribution with mean _i,i=1,2,...,k, and the functions to be estimated are (i) (d_i/_i) and (ii) (d_ii). When the total cost of sampling at the second phase is c _iN_i and is fixed, allocations using the Bayes approach are obtained so that the estimation is as precise as is possible.     

On optimal investiment strategies

Suppose an investor has a fixed decision horizon and an appropriate utility function for measuring his or her utility of wealth. If there are only two investment vehicles, a risky and a risk-free asset, then the optimal investment strategy is such that, at any time, the amount invested in the risky asset must be the product of his or her “current risk tolerance” and the risk premium on the risky asset, divided by the square of the diffusion coefficient of the risky asset. In the case of more than one risky asset, the optimal investment strategy is similar, with the ratios of the amounts invested in the different risky assets being constant over time.     

A proposed method for the analysis of public health policy in less developed countries

The study of public health policy in the less developed countries (LDCs) is handicapped by both lack of adequate data and gaps in conceptual apparatus. A new conceptual model is proposed that would be used for future policy analyses to assess what changes in health status of population in LDCs can be expected as direct functions of increased health service resources, and of improved environmental and econosociocultural conditions.While direct policy analysis is ill-advised at this time due to data inadequacy, the model is illustrated using data presently available for twenty-five relatively homogeneous sub-Sahara African countries. Within the limitations of available data, the findings suggest that reductions in mortality in the region might best be achieved by making appropriate health resources available to the populations. Study findings also suggest that physicians contributed more during the study period to the variance in physical health status than did medical assistants.     

A NONPARAMETRIC TEST AGAINST ORDERED ALTERNATIVES FOR DATA DEFINED BY INTERVALS

Abstract. The paper deals with a generalization of the Jonckheere test against ordered alternatives which allows for arbitrary censoring. It includes some previously published tests as special cases.     

Steady state and portfolio concept in R & D management

This paper describes a new approach for closing the gap between the tools for strategic goal management and operational management in Pharmaceutical R&D. The strategic level may concern with expectation of sales, rising from new products and with total R & D budget. The operational level concerns with project selection, project and multiproject management problems, solution of project related technical problems, determination of the size of the various functions and the functional management. This new method combines the R & D project portfolio management with a steady state concept allowing the attainment of a constant number of projects under development and a continuous full use of the capacity available.