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31.
Abstract

Over the past few years an unusually intense struggle over the future of the Lake Michigan fishery has occurred in the coastal communities of Racine and Kenosha. This struggle has engaged participants on the local, state, and national levels in the debate over the fishery as it is potentially impacted by the presence of environmental toxins, the rising cost of fish stocking and management, and conflicting user group demands. We describe three cases where urban sports anglers, with the assistance of university based social scientists, participated in state and city public policy decisions. After discussing this research and its policy implications, we propose a general public participation paradigm termed the Reciprocal Development Model.  相似文献   
32.
Abstract

Urban waterfronts are increasingly the focus of revitalization efforts designed to enhance tourism and recreation. The evolution of urban waterfronts suggests that these resources experience distinct stages of introduction, growth, maturity, decline, and sometimes revitalization. In this paper the product life cycle is broadened to describe the evolution of the waterfront district of Galveston, Texas. Implications of the product life cycle model of urban waterfront revitalization pertain to public policy formation, “product”; development, and management response to different life cycle stages.  相似文献   
33.
In this paper, in which the author attempts to redress the lack of attention by economists to ferry operation, a simple pricing model, based on marginal cost pricing, is developed.  相似文献   
34.
Standardized and free-format questionnaires on the state of coastal management were fielded to coastal management practitioners during three workshops and a national feedback and recommendation workshop. The most commonly cited responses were identified for each of 13 political regions and overall trends were identified. Management frameworks frequently included research, community organizing, education, livelihood, resource enhancement, resource protection, regulation, and networking components. Gender issues, documentation, and infrastructure investment were rare. The most commonly perceived environmental problem was illegal/ destructive fishing and its associated overfishing and low fish catch. The most commonly cited socioeconomic problem was the inadequacy of law enforcement. The best monitored variables were usually those related to environmental management: status and change of habitats, resources, and degree of enforcement/patrolling activities. The most common nonregulatory enhancement, aside from environmental education (which is the most popular), was mangrove reforestation. In terms of regulations, the majority of the respondents have reportedly formulated an integrated coastal management plan. In practice, regulating destructive and illegal fishing practices and then the establishment of fish sanctuaries are the next most implemented. The most popular quality-of-life enhancement strategies focused on the improvement of sustainable fishing as a livelihood and on a variety of supplementary livelihoods. The most usual institutional intervention being implemented was the setting up of local community people's organizations. Major factors which may influence success or failure of coastal management and recommendations on research, community organizing and livelihood, legislation and policies, implementation and coordination, and networking are also summarized.  相似文献   
35.
Although the success of marine protected areas (MPAs) and associated zoning schemes is largely dependent on stakeholder acceptance and support, there have been relatively few studies examining the response of recreational stakeholders to MPA proposals. This study investigates the response of recreational boaters to a proposed MPA in British Columbia, Canada. Using a structured questionnaire (n = 543) and a focus group (n = 6), the research examines the level of support for the concept of marine zoning and identifies key factors influencing support or opposition. Results indicate that a small majority of recreational boaters support the concept of marine zoning, but that there are areas of concern that ought to be addressed as MPA implementation proceeds. Support for zoning was strongly related to perceived benefits, particularly environmental benefits. Furthermore, perceived benefits overall were found to outweigh concerns as determinants of recreational boater support for zoning. Major dimensions of opposition included perceptions of over-regulation, loss of access for boating, and mistrust of the government. A suggestion is that such concerns may be mitigated through focused communication and meaningful involvement of boaters in the zoning process.  相似文献   
36.
In the presence of biofilms, stainless steels (SS) exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential (Eco,) behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor (an anthropogenically disturbed area) was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms (especially Navicula sp.) on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island (an undisturbed area). The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.  相似文献   
37.
汽车筒式液阻减振器技术的发展   总被引:29,自引:1,他引:29  
分析了汽车乘坐舒适性/行驶平顺性和操作稳定性对筒式液阻减振器特性的要求,提出汽车在不同行驶工况减振器特性的要求是不的;分析了被动式减振器的发展历程及非充气和充气减振器的特点,阐述了机械控制式可调阻尼减振器,电子控制式减振器以及电流变和磁流变液体减器等的结构特点,工作原理及其动态特性;分析了筒式液阻减振器其于经验设计/实验修正开发方法的缺点,阐述了基于CAD/CAE技术的现代设计开发方法的过程及其关键问题,最后分析了我国筒式液阻减振器技术的发展状况及问题,展望了减振器技术的发展前景。  相似文献   
38.
This paper documents the development of a simple method for identifying and/or predicting freeway congestion using single loop detection systems. The proposed algorithm is simple and easy to incorporate into most freeway management systems. The Washington State Department of Transportation's Traffic Systems Management Center (TSMC) sponsored the original study. The investigation also led to a recommendation to replace the original TSMC definition of congestion or forced flow conditions with a more reliable indicator. Although, the TSMC has recently implemented a more advanced prediction system based on fuzzy set theory and neural networks to further identify patterns and rules for ramp metering strategies, the findings presented here continue to be constructive to freeway managers looking for quick and easy analyses that rely solely on single‐loop detection systems. The Seattle Area freeway study section used for the original study was the portion of mainline 1–5 northbound starting at the downtown Seattle Station 108 and ending at the Mountlake Terrace Station 193. Several days' worth of volume and lane‐occupancy data were collected for the afternoon time period from 2:30 p.m. to 6:30 p.m. Time intervals of 20 seconds were chosen for each data collection period. Important products of this research include the following:
  • simple, and more reliable criterion for the definition of “bottleneck” or forced flow conditions than that originally used by the TSMC.
  • simple, and reliable criterion for predicting impending “bottlenecks” or forced flow conditions.
  • A proposed variable for improved selection of the appropriate metering rate. (Further analysis of the use of this variable for determining metering rates is recommended for future studies.
The proposed criteria are simple and easy to incorporate into current freeway management computer systems. Further investigation of freeway performance measurement using volume and occupancy data obtained from single‐loop systems is currently being performed.  相似文献   
39.
Most research and applications of network equilibrium models are based on the assumption that traffic volumes on roadways are virtually certain to be at or near their equilibrium values if the equilibrium volumes exist and are unique. However, it has long been known that this assumption can be violated in deterministic models. This paper presents an investigation of the stability of stochastic equilibrium in a two-link network. The stability of deterministic equilibrium also is discussed briefly. Equilibrium is defined to be stable if it is unique and the link volumes converge over time to their equilibrium values regardless of the initial conditions. Three models of route choice decision-making over time are formulated, and the stability of equilibrium is investigated for each. It is shown that even when equilibrium is unique, link volumes may converge to their equilibrium values, oscillate about equilibrium perpetually, or converge to values that may be considerably different from the equilibrium ones, depending on the details of the route choice decision-making process. Moreover, even when convergence of link volumes to equilibrium is assured, the convergence may be too slow to justify the standard assumption that these volumes are usually at or near their equilibrium values. When link volumes converge to non-equilibrium values, the levels at which the volumes stabilize typically depend on the initial link volumes or perceptions of travel costs. Conditions sufficient to assure convergence to equilibrium in two of the three models of route choice decision-making are presented, and these conditions are interpreted in terms of the route choice decision-making process.  相似文献   
40.
越来越多的机构开始为交通系统的可持续发展定义,并试图将这一概念融入区域交通规划过程.然而,只有极少数的区域规划机构意识到了交通系统和土地利用变化给经济、环境和社会生活质量(这三者通常被认为是可持续交通系统的三个基本方面)带来的广泛影响.首先,论述了使用多个可持续发展指标的多准则决策方法,并应用其评估亚特兰大大都市区的三...  相似文献   
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