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1.
Daganzo (1977, 1979), Daganzo and Sheffi (1977), Sheffi (1985), and Sheffi and Daganzo (1980) have used one assumption about traveler behavior in developing estimation techniques for the stochastic route-choice problem and another assumption in predicting flows on networks by using the same model. In estimation, they calculate the congested travel costs of the network links from observed flows on the network, and the network is loaded based on these costs. In prediction, they follow their stochastic user-equilibrium assumption by which travelers evaluate costs using the mean of the observed flows (or equilibrium flows). The travel-cost coefficient obtained from the loading method systematically overestimates the true travel-cost coefficient from which the observed flow data (which must be used in loading) is generated. The estimates of the same coefficient, obtained in this paper, by constraining the estimation results to conform to the equilibrium conditions are unbiased, and only marginally less efficient (have larger standard deviations). The average percentage error and inefficiency of the link flow predictions based on the loading method increases as the level of congestion on the network rises. In contrast, the average percentage error of link flow predictions based on the equilibrium estimation method declines and their efficiency remains very high as the level of congestion on the network rises.  相似文献   
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Existing research suggests that external sources of finance, such as foreign aid and natural resource rents, allow states to generate revenue independently of their societies, disincentivizing them from forming close links with their citizens and severely problematizing the notion of a social contract. In Lagos, Nigeria's commercial capital, a series of personal income tax reforms have seen an increase in taxpayer compliance. Considering Lagosians’ perceptions of their relation with the state government, this study examines whether the state had to ‘earn’ its revenue by developing a closer relationship with its citizens, and whether citizens responded through a greater willingness to pay tax. It explores how citizens understand this relationship, what role they perceive themselves to fulfil, and what their expectations are for the future of state–society relations. The study shows how, through efforts to visibly link tax to service delivery, a social contract is emerging between Lagos State and its citizens — but that this relationship differs among groups, in that it is shaped by pre‐existing concepts of public organization and modes of political engagement.  相似文献   
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The restoration of paintings on elements in cultural heritage buildings (fundamentally, churches) involves two structural problems: capturing the geometry of the construction element and its development. In many cases, the geometries are regular (e.g., cylinders, spheres, elliptical domes). However, there are cases in which the elements cannot be adapted to any known geometry, much less one that can be mathematically developed. The development of surfaces becomes essential for the restoration of paintings over “flat elements” (over which work is performed on the ground) that are subsequently transferred to the real surface (ceilings). The mathematical transformations that allow regular geometries to be developed are widely known (cartographic projections). However, when the geometry is irregular, there is no development. This study presents a new methodology based on differential rectification and its application for the development of oculi in the Los Santos Juanes Church (Valencia), whose geometry is completely irregular both in shape and as a result of construction defects (and damage caused by fire). The present study focuses on the restoration of paintings damaged by fire.  相似文献   
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Alex M. Nading  Josh Fisher 《对极》2018,50(4):997-1015
While scholars frequently frame conflicts over urban waste in terms of a politics of infrastructure, this article frames such conflicts in terms of a politics of organization. In 2008, self‐employed recyclers in and around Managua, Nicaragua blockaded local dumps in an effort to secure rights to scavenge for resellable material. Over the course of this “garbage crisis”, a material and semiotic entanglement of human labor organization with animal ecology became politically salient. At different points, recyclers were compared to ants (hormigas), vultures (zopilotes), and scorpions (alacranes). State officials, NGOs, and recyclers themselves used these animal metaphors to describe the organization of waste collection. Drawing on theories of value from political ecology and economic anthropology, as well as analysis of the deployment of these “organic” metaphors, we outline an “organizational politics” of urban waste.  相似文献   
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The city of Herculaneum (Naples, southern Italy), buried by the volcanic eruption of Mount Somma-Vesuvius in 79 ad, is a key site for understanding the timber economy during the Roman period. In this paper, the results of charcoal analysis of different building element types are presented. Beams, joists, poles, planks and door and window frames were investigated allowing us a view of which timber the Romans preferred for building in this area. We also fit the taxonomic results into the reconstruction of the ancient Campanian landscape, and finally, we discuss the knowledge that the Romans had about the technological properties of the wood that they used for building and the possible selection criteria that they followed in choosing them. Coniferous timber is the preferred material for building purposes. Abies alba is especially used, this fact confirming its stronger presence in southern Italian woods during the past and suggesting that its decline is mainly due to human overexploitation. The large presence of Cupressus sempervirens, selectively used for the production of poles, confirms that this tree was cultivated in plantations for timber production in the Vesuvius area. Furthermore, it might indicate that cypress could have been present as a natural tree in the local vegetation, suggesting a forest type that nowadays almost completely disappeared from this area and from the entire Italy. The findings of Juglans regia, Pinus pinea and Olea europaea, typical elements of the Mediterranean cultural landscape, show that their use was not limited to fruit production and that Romans also appreciated their timber. Beside these local resources, the presence of Picea abies and Picea/Larix indicates the importation of timber from northerly regions, probably the northern Apennines and the Alps.  相似文献   
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In this paper, we argue that beyond understanding nations as imagined communities, the metaphor of an ‘imagined family’ or ‘filial community’ is a more useful concept towards understanding links between gender and nationhood as family relations in four ways: (1) providing a clear, hierarchical structure; (2) prescribing social roles and responsibilities; (3) being linked to positive affective connotations; and (4) reifying social phenomena as biologically determined. In order to empirically substantiate our claim, we will explore the prevalence and use of family metaphors in a key symbol of nationhood discourses. Through a qualitative analysis of national anthems as ‘mnemonics of national identity’, we demonstrate the widespread presence of family metaphors, discussing how they reproduce ideas of family and gender. Finally, we discuss how the ‘imagined family’ as present in anthems and other forms of national representation could inform future studies of nationalism and national politics.  相似文献   
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Recent excavations in Ciemna Cave in the Pr?dnik valley near Ojców, southern Poland have brought to light new stratigraphic and techno-typological evidence concerning Late Middle Palaeolithic groups and their cultural affinities. In 2007, excavations began in the hitherto-unexplored main chamber of Ciemna Cave, with the goal of clarifying the results of previous work in other parts of the cave. During excavation the rocky floor of the cave was reached. About 1000 stone artifacts have been collected to date. Three cultural traditions have been documented: Mousterian, Taubachian, and Micoquian. Within the Micoquian tradition, three cultural levels were observed, which enriches the previous understanding of occupational phases at the site. These findings permit revision of the traditional terms “Pr?dnik industry” and “Pr?dnik technique.”  相似文献   
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East Africa is home to a rich array of stone-tool traditions that span human prehistory. It is unsurprising, therefore, that the region attracted pioneer prehistorians in the early twentieth century, including L. S. B. Leakey, E. J. Wayland and T. P. O’Brien, who created the first cultural framework for East African prehistory during the 1930s. Although aspects of this framework remain relevant today, others have become misunderstood relics of an old classification system that hinders current research. This is particularly evident in the classification of a Later Stone Age (LSA) culture – the Kenya (East African) Aurignacian, later known as Kenya (East African) Capsian. Although this cultural entity was redressed during the 1970s and 1980s and redefined as the Eburran industry, there is still mystique surrounding the current status of the Kenya Capsian, its original scope and definition, the relationship with the Eburran and its position within a modern understanding of the East African LSA. This is largely due to paradigmatic shifts in researcher attitudes, leading to the use of the Eburran as a false proxy. It is necessary now to completely remove the term Kenya Capsian as an indication of similarity among the different LSA technologies. However, there also needs to be less emphasis on the importance of the Eburran and recognition that it is just one example of a multitude of diverse localised LSA industries. This will open the way for future research into the LSA and facilitate our greater understanding of recent prehistory in East Africa.  相似文献   
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