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151.
E Van der Voort 《Omega》1982,10(5):507-523
This article describes the EC-EFOM 12C model in general and refers where possible to existing documentation. It also reports on the first completed experimental case study and on planned future analysis. This model was developed in one of the research programs undertaken by the European Commission aimed primarily at multinational studies. Data are obtained from research carried out by an interactive network of national implementation teams working with a central group at the Commission. The energy system used is an oriented network carrying the primary energy over intermediate stages till finally meeting consumers' demand. The numerical information, constituting the attributes that characterise the various energy transformation processes, is stored in the European energy data base. About 225 transformation processes distributed over 17 subsystems characterised for six time periods up till 2020 for all EC countries are involved. The management of the data base is performed by an interactive software and this data base is designed for use in simulation studies and for linear programming optimisation with various objective functions. The model has been used in a parallel case study to explore substitution possibilities between an investment policy reducing the primary energy imports and one where these investments are restrained at the cost of having to import more primary energy. Results are shown and briefly discussed. Finally the relationship of this EFOM 12C model with the other EC models developed in the same research subprogram is outlined.  相似文献   
152.
How does the chief executive of a large complex organization maintain strategic momentum? This represents a great challenge when there are no obvious external threats, and no obvious reasons for having a concerted action. Floris Maljers, Charles Baden-Fuller and Frans van den Bosch explore the inherent tensions which exist between stability and change. Change is necessary to maintain success, but too much change is disastrous. The authors argue that there are several possible solutions to this paradox, including that of generating periods of intense activity followed by periods of comparative stability and incremental improvement. Using the introspection of one of the CEOs of Unilever, who held office from 1984 to 1994, the authors examine how these tensions were played out and resolved.  相似文献   
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154.
A growing literature examines whether the poor, the working class, and people of color are disproportionately likely to live in environmentally hazardous neighborhoods. This literature assumes that environmental characteristics such as industrial pollution and hazardous waste are detrimental to human health, an assumption that has not been well tested. Drawing upon the sociology of mental health and environmental inequality studies, we ask whether industrial activity has an impact on psychological well-being. We link individual-level survey data with data from the US. Census and the Toxic Release Inventory and find that residential proximity to industrial activity has a negative impact on mental health. This impact is both direct and mediated by individuals' perceptions of neighborhood disorder and personal powerlessness, and the impact is greater for minorities and the poor than it is for whites and wealthier individuals. These results suggest that public health officials need to take seriously the mental health impacts of living near industrial facilities.  相似文献   
155.
What are the dimensions of well-being? That is, what universal goals need to be realized by individuals in order to enhance their well-being? Social production function (SPF) theory asserts that the universal goals affection, behavioral confirmation, status, comfort and stimulation are the relevant dimensions of subjective well-being. Realization of these substantive goals and the perspective on opportunities to realize these goals in the future contributes to the affective and cognitive component of well-being. The theoretical elaboration of this theory has been published elsewhere. This paper provides a measurement instrument for the dimensions of well-being. To measure levels of affection, behavioral confirmation, status, comfort and stimulation and empirically validate the dimensions of well-being, the SPF-IL scale was developed. This paper presents findings from a pilot study (n=145), the main study (n=1094), a test–retest examination (n=163), and a validation study (n=725). The measurement model was tested by means of structural equation modeling. Confirmatory factor analysis supported the dimensional structure of well-being indicating construct validity. The overall fit of the model was sufficient, in spite of the somewhat problematic measurement of status, and the test–retest study showed an acceptable level of stability. As for the content validity of the dimensions and their measurement, various sub-studies showed that the SPF-IL scale is a valid instrument, doing at least as well as popular measures of overall well-being but also specifying its dimensions.  相似文献   
156.
This article describes a method for reclassifying causes of death in the Netherlands for the period 1875–1992. Two criteria should be met to obtain a useful classification to study the epidemiological transition. First, the categories should be nosologically continuous over the period under study and second, there should be enough detail in causes which are important in the context of the epidemiological transition viz. communicable diseases, non-communicable diseases and external causes of death. A method developed by Vallin and Meslé (1988), which involves ‘dual correspondence tables’ and ‘fundamental associations’, was used to create nosologically continuous categories. These categories were tested for statistical continuity during the transition years of one ICD-revision to the next, using ordinary least squares regression analysis. The reclassification procedure resulted in a nested classification consisting of three levels of refinement of causes of death: 27 causes, 1875–1992; 65 causes, 1901–1992; and 92 causes, 1931–1992. On the basis of this classification, 43% of all deaths in 1875–79 and 98% of all deaths in 1992 could be allocated to either communicable diseases, non-communicable diseases or external causes.  相似文献   
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158.
This paper develops a novel framework to evaluate the integral performance of order picking systems with different combinations of storage and order picking policies. The warehousing literature on order picking mostly considers minimizing either elapsed time or distance as the sole objective, whereas warehouse managers in a supply chain have to look beyond single‐dimensional performance and consider trade‐offs among different criteria. Thus managers still need a unified and efficient framework to select a portfolio of appropriate order picking policies from a multi‐criteria and contextual perspective. Our framework—combining data envelopment analysis, ranking and selection, and multiple comparisons—provides an efficient methodology to simultaneously analyze several interrelated problems in order picking systems with multiple performance attributes, such as service levels and operational costs. We demonstrate our approach through comprehensive evaluations of order picking policies in three low‐level, picker‐to‐parts rectangular warehouses facing demand variations.  相似文献   
159.
The impact of R&D on growth through spillovers has been a major topic of economic research over the last thirty years. A central problem in the literature is that firm performance is affected by two countervailing “spillovers” : a positive effect from technology (knowledge) spillovers and a negative business stealing effects from product market rivals. We develop a general framework incorporating these two types of spillovers and implement this model using measures of a firm's position in technology space and productmarket space. Using panel data on U.S. firms, we show that technology spillovers quantitatively dominate, so that the gross social returns to R&D are at least twice as high as the private returns. We identify the causal effect of R&D spillovers by using changes in federal and state tax incentives for R&D. We also find that smaller firms generate lower social returns to R&D because they operate more in technological niches. Finally, we detail the desirable properties of an ideal spillover measure and how existing approaches, including our new Mahalanobis measure, compare to these criteria.  相似文献   
160.
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