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41.
ABSTRACT

A dynamic model for marginal cost pricing of port infrastructures links costs to system performance by combining a power-law function with time-dependent queueing analysis. Additionally, the model incorporates the marginal cost of capacity, including the effects of economies of scale. This allows the calculation of the marginal cost price under a dynamic framework. The model accounts for nonlinear behaviour of port demand, which is sensitive to price and service levels. The effects over time of cost and service levels on the port’s operational performance are quantified. The proposed model allows determining the optimal timing for capacity investment. The model is a starting point for the application of marginal cost pricing to ports. However, for practical application of such pricing method it is necessary to apply a system’s approach, as productivity and costs must be assessed at the terminal’s component level. This should allow the derivation of a marginal cost function at the terminal’s component level.  相似文献   
42.
On 19 October 1989, the International Maritime Organization adopted a joint uslliberian resolution meant to advance international cooperation in maritime casualty investigations. This resolution reflected an international determination to achieve greater cooperation between different states in investigative matters, in a manner consistent with international law. This paper examines how the IMO resolution addresses some of the inherent problems in such a multi-national industry. It also examines the question of whether us lawmakers may, or should, impose stricter controls and restrictions unilaterally on foreign-flag ships which call on us ports.  相似文献   
43.
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   
44.
This paper presents the joint optimization of signal setting parameters and dynamic user equilibrium (DUE) traffic assignment for the congested urban road network. The simulation-based approach is employed to obtain the DUE condition for the case of multiple-origin multiple-destination traffic flows. The dynamic traffic assignment simulation program (DTASP), developed in C language is used to assign the traffic dynamically on the road network, whereas method of successive averages (MSA) is modified and used to arrive at the DUE condition. The artificial intelligence technique of genetic algorithms (GAs) is applied to obtain the optimal signal setting parameters and path flow distribution factor for DUE condition. The methodology developed in such a way that joint optimization of signal setting parameters with DUE is obtained. The proposed method is applied to the real network data of Fort Area of Mumbai city comprising of 17 nodes and 56 unidirectional links with 72 Origin–Destination pairs, where all the 17 nodes are signalized intersections. The traffic flow condition for the optimized signal setting parameters is considerably improved compared to the existing signal settings. The results prove that the GA is an effective technique to solve the joint optimization problem for the real network data.  相似文献   
45.
This paper analyses the occupational future of the American merchant seaman. Reasons for the decline, foreign competition, technological change, effective manning and the feast or famine cycle are analysed. Strategies for the resurgence of the occupation are discussed.  相似文献   
46.
Abstract

Although New Zealand has a population of 3 million and a coastline of about 10,000 miles there are already heavy pressures on some parts of it. Historically, subdivisions of less than 10 acres require the setting aside of a one‐chain esplanade reserve as part of a general reserve contribution. Some national and regional parks also include significant areas of coast. Recently the Lands and Survey Department has commenced a detailed study of the coastline. Another very recent development is the requirement of an Environmental Impact Report for all major government works. The Waitemata Harbour has been the subject of a detailed study and the reports are now beginning to appear. There has been a heavy demand for shallow bays and estuaries for sanitary land fill, as well as for dredge fill. The main pressure on the coast at present is for holiday cottage sites and some legislative changes may be necessary. In the future new marinas will probably be considered particularly in relation to the extent they provide for the general public rather than a selected few. Industry is only just beginning to make an impact upon the coast. New power stations, natural gas or thermonuclear, are likely to be located on the coastline and this would bring some environmental problems. Recently, it has been argued that to ensure wise use of the coastline there should be national, rather than local or regional, control by a specially appointed Coastal Commission.  相似文献   
47.
Abstract

The economic and environmental consequences of a proposed Louisiana superport have been studied by researchers during the last three years. These studies provided technical information and management alternatives. Management alternatives included state control to avoid multiple superport developments, details for an Environmental Protection Plan, comparisons of onshore and offshore sites, and planning for ancillary development. Policy decisions which resulted include many of the recommendations of the research. It is suggested that environmental research can influence policy decisions and limit the options available to a decision maker provided some legal structure is created, quality control is implemented, and technological and environmental problems are recognized. Various analytical tools, such as energy cost accounting, group critique, and simulation models, have wide application for use in coastal zone management.  相似文献   
48.
Abstract

The National Park Service is required by law to conserve nationally significant resources for public benefit. Susceptibility to local short‐term economic pressures and a lack of understanding of resource dynamics can jeopardize mandate compliance. Assateague National Seashore is an example of a dynamic barrier island where early understanding of ecologic factors should have preceded its establishment and must precede its management and development. Research conducted on a similar system has demonstrated the dramatic environmental impacts and high maintenance costs associated with an inappropriate recreation management scheme. Alternatives are available which minimize resource degradation and maintenance costs without restricting visitation. To better ensure incorporation of long‐run ecologic and economic criteria into the decision‐making process, a proposal is put forward which recognizes the need for an expanded research effort and close adherence to early planning steps.  相似文献   
49.
Abstract

One of the consequences of sea level rise resulting from the greenhouse effect is increased coastal erosion. This article discusses a model of erosion that can be used to estimate the response of beaches to sea level rise. The model is applied to Ocean Beach, California, with particular attention to the consequences of accelerated erosion for the San Francisco Westside Sewer Transport. Results obtained show that erosion produced by accelerated sea level rise could cause substantial damage to the structure. Large expenditures on beach nourishment will be required to protect the transport and the recreational value of the beach.  相似文献   
50.
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