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ABSTRACT A common problem with spatial economic concentration measures based on areal data (e.g., Gini, Herfindhal, entropy, and Ellison‐Glaeser indices) is accounting for the position of regions in space. While they purport to measure spatial clustering, these statistics are confined to calculations within individual areal units. They are insensitive to the proximity of regions or to neighboring effects. Clearly, since spillovers do not recognize areal units, economic clusters may cross regional boundaries. Yet with current measures, any industrial agglomeration that traverses boundaries will be chopped into two or more pieces. Activity in adjacent spatial units is treated in exactly the same way as activity in far‐flung, nonadjacent areas. This paper shows how popular measures of spatial concentration relying on areal data can be modified to account for neighboring effects. With a U.S. application, we also demonstrate that the new instruments we propose are easy to implement and can be valuable in regional analysis.  相似文献   
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Industrial Location Modeling: Extending the Random Utility Framework*   总被引:1,自引:0,他引:1  
Abstract. Given sound theoretical underpinnings, the random utility maximization‐based conditional logit model (CLM) serves as the principal method for applied research on industrial location decisions. Studies that implement this methodology, however, confront several problems, notably the disadvantages of the underlying Independence of Irrelevant Alternatives (IIA) assumption. This paper shows that by taking advantage of an equivalent relation between the CLM and Poisson regression likelihood functions one can more effectively control for the potential IIA violation in complex choice scenarios where the decision maker confronts a large number of narrowly defined spatial alternatives. As demonstrated here our approach to the IIA problem is compliant with the random utility (profit) maximization framework.  相似文献   
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The wreck of a 19th-century merchantman was surveyed and partly excavated in the course of archaeological fieldwork conducted prior to planned beach restoration in Ahrenshoop on the Baltic coast in north-eastern Germany. Extensive archival research led to the identification of the wreck and provided interesting details on the life and loss of a typical merchant sailing-ship of the mid-19th century.
© 2007 The Authors  相似文献   
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Archaeology in Europe has changed a great deal over the last 25 years and these changes have certainly affected maritime archaeology. As such they also define the practical skills that are needed. On the one hand of course, unlike other branches of European archaeology, maritime archaeology still has a major preoccupation with a well-funded ‘treasure-hunting’ industry and no lack of ill-defined and ill-considered project initiatives. High ethical standards are therefore necessary and the public debate should continue. But within the structure of archaeology and its management at large, maritime archaeology should also show what its major contributions can be. It can only do so if sufficiently trained personnel are available. It is against this background that the Maritime Archaeology Programme at SDU in Esbjerg is being shaped. This paper reviews developments in the field and outlines the approach to education developed at SDU in response.
Jens AuerEmail:
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Timber-framed wall buildings are seen all over Europe, especially in seismic regions, given its adequacy to resist earthquakes. The “Pombalino” buildings, developed after the great 1755 earthquake that destroyed Lisbon, constitute one of the best examples of historic seismic-resistant structures based on timber-framed masonry walls. The research presented in this article aimed at experimentally evaluating the seismic behavior of the “Pombalino” buildings. The experimental program was based on extensive dynamic testing on sub-structures of typical “Frontal” walls (the timber masonry walls), carried out at the LNEC (the Portuguese National Laboratory of Civil Engineering) shaking table. The tests comprised (a) seismic tests, in which the seismic action was applied with increasing amplitude in one direction; and (b) dynamic identification tests, aiming at evaluating the dynamic properties of the sub-structures and their evolution with damage accumulation.  相似文献   
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Within a full-scope modernization program of Portuguese secondary schools, technical inspections were conducted in order to: 1) identify the main degradation processes that affect different types of school buildings, and 2) provide recommendations for the rehabilitation projects. This article presents the constructive characteristics and a statistical analysis of the degradation condition of a particular type of Portuguese secondary schools, the Liceu, comprising a set of buildings with an invaluable historical and cultural importance and that is very iconic in terms of the historical period in which they were built—the Estado Novo. To that end, a database was designed in order to organize information gathered in the inspection of 15 secondary schools of Liceu typology. The aim of the database was to analyze the most frequent anomalies in this type of school buildings, taking into account the constructive solutions used and establishing statistical relationships between anomalies, probable causes and recommended rehabilitation works. Results obtained allowed concluding that the overall condition of these buildings which, in average, were 60 years old, was severe. The most frequent anomalies in both the buildings envelope and interior are mainly due to design and execution errors, water infiltration, and lack of maintenance. Although the school buildings analyzed are to some extent unique, most lessons learned from this study can be extrapolated to other countries, mostly Mediterranean, where during most of the 20th century, buildings were designed and constructed according to the same architectural and constructive principles, and were subjected to the same type of maintenance.  相似文献   
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Fire safety is an important issue of building safety, especially when the building’s fire load contents enhance the risks of fire deflagration. When existing timber structures are involved, the most usual way to improve its reaction to fire is to treat wood with fire retardants. This study focuses on the surface protection of existing timber roof structures against fire, through the use of fire retardant (FR) treatments applied on site. An experimental investigation was carried out to study the effect of FR treatments on timber reaction to fire, with a special emphasis on timber members with biological deterioration and previously treated with preservative products. The behaviour and effectiveness of intumescent and non-intumescent treatments was also investigated. The study showed that the application of FR treatments improved the reaction to fire of timber, even in the presence of previous preservative treatments. However, the choice of the specific FR treatment should take into account the substrate conditions. In addition, test results suggest that protection systems involving multi layers (intumescent and non-intumescent) with different functioning modes each are likely to have a good global performance on the protection of timber elements against fire.  相似文献   
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