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1.
Mobile ICTs and physical mobility: Review and research agenda   总被引:1,自引:0,他引:1  
The question of the relationship between the spread of communication tools and the physical mobility of individuals is not new and arose with the arrival of the fixed telephone and, more recently, the development of the Internet and especially e-commerce. The extraordinary spread of individual, especially portable, communication tools like the mobile phone, has recently generated new interest in this topic in the fields of transportation economics, geography and sociology. This article discusses the main topics that have been explored, from the debate between complementarity and substitution to analyses in terms of interactions with the spatiotemporal organization of daily activities, the size and maintenance of social networks, and, finally, perception of travel and spaces. We then identify several issues that we think merit further exploration.  相似文献   
2.
Abstract

The West Coast Groundfish Trawl Catch Share Program was designed to achieve multiple economic goals and objectives, including increasing net benefits, profitability, flexibility, and utilization of harvest allocations. In this article, we leverage seven years of comprehensive cost and earnings data to evaluate progress towards these goals with a focus on harvesters. Our assessment shows that five years post-implementation, net benefits to the nation have doubled, and indicators of productivity and profitability have increased. The fleet that targets Pacific whiting has seen the largest gains, due in part to increases in total allowable catch and the elimination of the race-to-fish. However, increased revenues have not been realized to the degree that was expected for harvesters targeting non-whiting groundfish, partly due to lower than predicted consolidation and relatively low quota utilization. Economic outcomes indicate that tradeoffs exist between certain objectives of the program, specifically between achieving full utilization and flexibility for harvesters. Results are discussed in the context of the design and evaluation of catch share programs for diverse, multispecies fisheries.  相似文献   
3.
Abstract

Aquaculture and its specialized cousin, mariculture, provide some potential additional food sources and economic revenues. Technological barriers to increased mariculture production are being removed, but many legal and institutional barriers remain. Examples of the current and potential regulation of mariculture in Texas by state and federal authorities are examined. The effect of various state and federal regulations on the development of mariculture is discussed from a legal and institutional viewpoint. The potential for growth of mariculture is considered questionable without regulatory reforms, particularly at the federal level.  相似文献   
4.
Reliability in cost estimates in publicly funded projects is more important today than ever with increased governmental funding to infrastructure projects and associated accountability requirements, but surface transportation projects, large and small, in the United States have a legacy of cost overruns. The problems with these overruns start with the cost estimation process before projects begin. Studies have shown that early cost estimations reflect best-case scenarios rather than realistic expectations, and have attributed technical, economic, psychological, and political reasons for underestimation. The primary objectives of this research were to determine how costs have been presented and updated in environmental impact statements, to identify endemic technical problems with cost estimation during the environmental review of surface transportation projects, and to develop recommendations for improving cost estimation and disclosure. Cost estimation methods were analyzed from the documents of 100 projects, including draft environmental impact statements, final environmental impact statements, and records of decision. The study concluded that the lack of guidance on how to include cost estimation in environmental review revealed itself in the level of detail and attention given to estimating costs. Agencies omitted or included various aspects of cost estimation randomly. Professional organizations should fill the gap of the need for specific guidance to cost estimation for environmental review so it can evolve as a state of the practice.  相似文献   
5.
本文介绍了印第安纳州为确保桥梁安全运营而实施的桥梁荷载分级方法,以及实施背景、目的和使用方法等.  相似文献   
6.
Coastal areas are commonly the focus of a range of human activities and uses. Beaches are one example of multi-use coastal environments, accommodating activities linked to leisure and recreation, amenity, conservation and business, often simultaneously. Ireland is no different in this regard, as its beach resources provide a range of goods and services of societal value. Ireland has 16 coastal counties and their associated local authorities have a beach management remit, a role that can present a number of challenges. The use of beach bye-laws is one option to support management of beach environments by local authorities. Local authority personnel tasked with beach management from each coastal local authority were surveyed to assess the actual and potential role of beach bye-laws in contributing to more effective management of beach environments and to broader coastal management. Usage of beach bye-laws varied across local authority areas and evidence suggested that the efficacy, use, and implementation of beach bye-laws differed from county to county. Beach bye-laws offer potential but interaction with other initiatives as part of a wider program for coastal management may yield improved results.  相似文献   
7.
Abstract

The authors present an assessment of the Coastal Conservancy's efforts to consolidate small, substandard lots in the Santa Monica Mountains. Emphasis is placed on the ‘ ‘lessons learned’ ‘ by the Conservancy in its project experience as those lessons may be applicable to related efforts elsewhere. Finally, alternative means of lot consolidation are suggested. This assessment should be of relevance to other programs nationwide to address the problem of antiquated subdivisions.  相似文献   
8.
Combined ships have been built in order to minimize ballast voyages and to take advantage of the highest freight rates on either market, oil or dry cargo market. Then their versatility should have been very attractive for shipowners. So why has the combined fleet shrunk to such an extent? This paper provides an analysis of the employment of combined ships, how this has been influenced since the 1970s, and how these ships may have influenced oil and dry market balances. The research identifies the decisive role that grain trade seems to be able to play about shifting markets, and that combined ships were the largest bulk carriers in the 1970s. It is an opportunity to stress that freight rates are not always the only salient point for a shipowner's decision and to consider the importance of combination ships contribution to shipping markets.  相似文献   
9.
Abstract

Historic shipwrecks are a recently recognized group of historic resources. These shipwrecks attract sport divers, archeologists, and treasure hunters. States have always claimed the historic shipwrecks embedded in their submerged lands. States manage these resources as part of their historic preservation programs. However, since 1981, state authority has been challenged by the federal court sitting in admiralty. Cases have been decided in Florida, Massachusetts, Maryland, Texas, and Georgia; however, only one Florida case went against the states but the expensive litigation has been a drain on state treasuries.

Bills currently before the U.S. Congress will affirm state title and encourage states to put effort into state programs for historic shipwrecks. This article briefly describes the populations interested in shipwrecks, current case law, state law and state programs, and finally the federal legislative proposal.  相似文献   
10.
Complexity of car park activity is reproduced from a concurrent execution of behaviour of various drivers. This paper presents a step in the development of a multimodal traffic simulator based on multi‐agent paradigm and designed as a decision aid tool as well as a video game. The user‐player has the opportunity to test different scenarios. We propose an approach for designing the decision‐making rules and the learning mechanism for a car driver agent. For that, a panel of methods such as stated preference modelling, Design Of Experiments and data fusion is used. Initial behavioural models, based on similar preferences, are developed for specified categories. Each agent will adapt its behaviour after executing its learning process. Our approach can be used in order to optimize needs of road network users and those of people in charge of traffic regulation. A demonstrator has been developed to test parking policies in an urban area as well as changes of car park characteristics.  相似文献   
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