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101.
Abstract

This article argues that using the public sector and the private market in the historically delineated and traditional ways offers only the bluntest of tools with which to approach the complex problem of coastal zone management. It therefore seeks to provide a basis for reformulating our understanding of sectoral responsibility with regard to resources management. First, it conceptually analyzes the relative strengths and weaknesses of the two sectors. Second, it examines three examples of coastal resources management—beaches and shorelands, artificial reefs, and coastal wetlands—in analyzing the complexities of the coastal management challenge and the limitations of our current approaches. Finally, we provide an alternative perspective on how these common property resource allocation decisions can be made.  相似文献   
102.
The U.S. Army Corps of Engineers administers the only nationwide regulatory program that controls development activities in U.S. waters and wetlands. This article examines the statutory authorities, jurisdictional limitations, and evolution of the current Corps regulations, which express a strong policy to protect wetlands, estuaries, and tidal waters from unnecessary dredging, filling, or other alteration. The article explains the organization and procedures of the U.S. Army Corps of Engineers and examines in detail several precedential permit cases which have developed and implemented the Corps “wetlands policy.”; The article also evaluates current and potential policies underlying the regulatory efforts of the Corps of Engineers.  相似文献   
103.
Abstract

Most scenery evaluation methodologies incorporate visibility extent. In New York's coastal zone, visibility mapping for planning and project studies is complicated by low topographic relief, and diverse configurations of water edge and upland surface character. A generalized visibility model has been developed, including macrolandscape, observer, and sight‐line recording. Based on a prior shorescape study of New York's coast, the Lake Ontario Port Bay site was selected to test alternative visibility methods. Within the study site, four “landscape control points”; were chosen which provided extensive views of representative land and water forms, and surface types. For each control point, four families of visibility mapping approaches were applied: primary (field observation); secondary (topographic maps and vertical air photo analysis); tertiary (physical topographic model); and quaternary (digital terrain computer model). Major study conclusions are: the methods require different resources; all methods readily produced visibility maps; all methods, except secondary, could be used to produce perspective scenes for subsequent content evaluation; all methods except primary omitted one or more elements of the general visibility model; all methods should incorporate field work due to critical viewer environment conditions; sensitivity analysis in each method produced ambiguous zones; each view map was different, particularly in the background. An integrated, multi‐approach strategy would appear desirable for most planning and project applications.  相似文献   
104.
Mandatory inspection and maintenance programs require on-road vehicles to be tested regularly and repaired if they are not in compliance with air emission regulations. We estimate the abatement cost function for a representative inspection and maintenance program. This is done by constructing a model of the statistical process that leads to non-compliance, parameterizing the model, and then by simulating the total abatement cost function. The model predicts that the marginal abatement cost for a major representative program is so high that even a small reduction in the abatement target leads to substantial cost savings to motorists. In addition, even for quite high levels of the abatement target, the optimal minimum testing age is substantially higher and the frequency of testing is much lower than is common in many jurisdictions.  相似文献   
105.
This paper presents the historical and cultural background relating to road improvement and road safety characteristics in Kenya, a developing country in East Africa. Some who come from low-developed areas of developing countries often take time to comprehend the modern transportation infrastructure, especially roads, and have difficulty assimilating and customizing the same to their culturally tailored modes.This paper discusses two case studies: one on the socio-economic impact following improvements to a 50-km, high-class, high-traffic-volume road and the other on the monitoring and evaluation of road safety aspects along the Northern Corridor in Kenya also following major road improvements.The road improvements to the Nairobi-Thika Highway (a trunk road) have attracted many investors along the highway corridor. The high-speed road has also brought with it the unfortunate consequence of speeding vehicles colliding with pedestrians crossing the road at undesignated locations.The Northern Corridor, the transportation corridor that links the Great Lakes Countries of the Democratic Republic of Congo, Burundi, Rwanda, and Uganda from the port of Mombasa in Kenya, has had high accident rates for a considerable amount of time. The results of monitoring and evaluation exercises on the Northern Corridor have shown that drivers are the major contributors in causing accidents, with a component ratio of 49.4%; pedestrians are next at 21.7%. Data also shows that 24% of the accidents along the Northern Corridor are fatal, which is of major concern. The study additionally indicated that the majority of road users have not been exposed to education or training on road safety.This paper presents a number of recommendations arising from the road safety study regarding possible improvements in aspects of road safety along the corridor and potential applications of those changes to other roads in general. For example, there are recommendations related to the geometric design of the road, driver training and behavior, vehicle maintenance, and the need to enhance road safety through the utilization of road safety parks where road users can undergo training and drills on road safety aspects.In conclusion, we argue that the rehabilitation of the Northern Corridor from Mombasa on the Kenyan coast to the border with Uganda has led to significant road safety improvement.  相似文献   
106.
3.12中国利用西方国家的TBM经验加速发展本国TBM技术的理由 3.12.1技术开发和革新是需要时间的  相似文献   
107.
There is a growing interest in traveller behaviour research to explore alternative information processing strategies (often referred to as heuristics or rules) adopted by individuals when assessing packages of attributes describing alternatives in a choice set, and making a choice. One popular attribute processing rule relates to attributes not being considered (i.e., being ignored), for all manner of reasons, referred to in the small but growing literature as attribute non-attendance or non-preservation. Researchers have used a mixture of methods to study the role of attribute non-attendance, including supplementary questions on whether each attribute is ignored or not, and methods in which the functional form of the utility expressions defining an alternative can recognise the possibility, up to a probability, of an attribute being ignored. Although supplementary questions are worthy of further consideration, despite the controversy as to the reliability of the response, recent interest has focused on ways to establish the incidence of attribute non-attendance without recourse to such evidence. In this paper we use an existing data set of choice amongst four attributes describing alternative car non-commuting trips, to illustrate the proposed method, and to compare values of travel time savings under each possible combination of non-attendance attributes relative to a model in which all attributes are assumed to be fully attended to. The paper reveals a major concern with the way that attribute levels and ranges are selected in the design of choice experiments, which can induce non-attendance situations where willingness to pay estimates cannot be obtained.  相似文献   
108.
There is growing interest in the notion that a significant component of the heterogeneity retrieved in random coefficients models may actually relate to variations in absolute sensitivities, a phenomenon referred to as scale heterogeneity. As a result, a number of authors have tried to explicitly model such scale heterogeneity, which is shared across coefficients, and separate it from heterogeneity in individual coefficients. This direction of work has in part motivated the development of specialised modelling tools such as the G-MNL model. While not disagreeing with the notion that scale heterogeneity across respondents exists, this paper argues that attempts in the literature to disentangle scale heterogeneity from heterogeneity in individual coefficients in discrete choice models are misguided. In particular, we show how the various model specifications can in fact simply be seen as different parameterisations, and that any gains in fit obtained in random scale models are the result of using more flexible distributions, rather than an ability to capture scale heterogeneity. We illustrate our arguments through an empirical example and show how the conclusions from past work are based on misinterpretations of model results.  相似文献   
109.
This paper reviews a number of themes that have played a crucial role in the debate on alternative contracting regimes for the provision of urban bus services. We have selected four crucial issues to reflect on: (i) contractual regimes (in particular competitive tendering as compared to negotiated performance-based contracts, as means to award the rights to provide service); (ii) contract completeness (focussing on ex ante and ex post elements); (iii) building trust through partnership; and (iv) tactical or system level planning for bus services. Experience in these areas suggests that competitive tendering has frequently not lived up to expectations and that negotiation is likely in many circumstances to deliver better value for money.  相似文献   
110.
John Bird 《Marine Structures》1993,6(5-6):461-474
The propertied of high strength GMA welds are controlled by bead size, in particular the weld metal microstructure which is controlled by weld cooling rate. Shielding gas composition is known to be important as regards the protection of the molten weld pool from atmospheric contamination. However the role of the shielding gas composition in developing weld metal toughness is less well documented. This paper attempts to identify those characteristics in the deposition of a weld which contribute to improved toughness in high strength steel welds.  相似文献   
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