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111.
Urban transportation is identified as a functional element in the broader context of urban facilities and services. From this point of view, the relative merits of separate information systems for transportation planning and general urban planning, as contrasted to unified systems for all urban management functions, are discussed. The overriding need to make the most effective use of urban resources argues strongly for the unification of urban information systems to the greatest possible extent consistent with the special data requirements of various functional programs. The need to identify and correlate data items for very small areal units and to keep current records of the constantly shifting patterns of social and economic activities in urban areas present difficult, but not insurmountable technical problems. However, the most serious barrier to the development and implementation of comprehensive urban information systems is concluded to be institutional, rather than technical, in nature. 相似文献
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115.
B. J. Thomas 《Maritime Policy and Management》1981,8(3):179-190
The absence of formal career-development programmes and the apparent low priority given to the development of human resources in the ports of developing countries has led to a severe shortage of suitably qualified and experienced managers. At the centre of this problem lies the formidable barriers to the establishment of a local training capability to meet the diverse and often specialized needs of this industry. This paper examines the nature and scale of the management-training requirements of the ports of developing countries. Further, it briefly describes the background to UNCTAD's role in the field of management training and outlines the objectives of its training strategy for the 1980s. An important component of this strategy is the 'Improving port performance project which is designed to prepare structured learning materials using audio-visual techniques and is proposed as one solution to establishing a local training capability in developing countries. 相似文献
116.
Patricia J. Moser 《Transportation》1972,1(1):55-67
This paper discusses the aesthetic and ecological effects of highways. Little is known about the subject at the present time, and thus this treatment cannot be considered in any sense definitive.Part I offers a definition of aesthetic quality and considers its relevance to highway planning. It is noted that, although the principles of rural freeway design (curvilinear alignments, variable medians, etc.) generally accord with the aesthetic character of rural areas, freeways are infinitely more difficult to integrate aesthetically into urban areas. Comparisons are made in this regard among basic types of freeways.Part II notes that the effect of man's presence on the earth's ecology has resulted in new systems and processes to which man is now subject. Highways, as works of man, affect him and his environment in ways which are known only imperfectly. Nevertheless, there are steps which can be taken to minimize the more obvious forms of damage to the environment which can result from highway building.Part III discusses procedures for incorporating aesthetic and ecological considerations into highway planning. No method yet proposed is in itself sufficient, and none leads to a decision on an objective basis. A generally acceptable method must await further research. In the meantime, every effort must be made to assure full and fair consideration of environmental effects on an ad hoc basis. 相似文献
117.
In this paper, the authors outline the structure of liner shipping systems with special emphasis on the question of whether feeder services are superior in economic terms to the more traditional and commonly-used multi-port-calling system. They describe the theoretical advantages of the former over the latter, and develop a model by which the optimal conditions both operate in may be determined. This model is then applied to a real situation to ascertain whether the theory works in practice. They conclude that the shuuttle/feeder system is worthwhile only in exceptional circumstances when specific route characteristics—low trade density; hinterland generated cargo; inland position of port; and heavy congestion—coexist. Despite the expense of multi-port-calling, it remains the most practical solution to the thin trade problem. 相似文献
118.
Yunyoung?Kim Koji?GotohEmail author Masahiro?Toyosada 《Journal of Marine Science and Technology》2004,9(2):70-79
This article considers microgenetic algorithms (GAs), which explore in a small population with a few genetic operators, for cutting-path optimization problems. The major difference between GAs and simple genetic algorithms (SGAs) is how to make a reproductive plan for an improved searching technique because of population choice. It is shown that GAs implementation reaches the near-optimal region much earlier than the SGAs approach, and the GAs give a better solution than simulated annealing (SA). The main objective was to determine what temperature distribution can be obtained from the solution of a travelling distributed heat source. The solution of the travelling heat source on nested raw plate provides information about the vertices of each nested part of the raw plate. From the fact that the initial temperature at a piercing point strongly depends on the heat flow which stems from the previous cutting contour, the temperature of all piercing points must be lower than the critical temperature after each cutting of the components of a part. The critical temperature is identified as the mechanical melting temperature of steels. A heuristic back-tracking method is introduced to find the near-optimum cutting path considering the minimum heat effect on deformation. The heuristic back-tracking method is incorporated with the GAs. 相似文献
119.
Toshiyuki?Shigemi Tingyao?ZhuEmail author 《Journal of Marine Science and Technology》2004,9(3):95-108
ClassNK has undertaken wide-ranging basic research covering many aspects related to the safety of ship structures, including design loads, structural analysis, strength assessment of buckling, collapse, and fatigue, and rational corrosion margins to develop new design standards which have transparency and consistency. Among the wide-ranging basic research, this article summarizes the results of extensive work on the design loads used for strength assessments of tanker and bulk carrier structures. The main aim of the research was to develop practical estimation methods of design loads with rational technical backgrounds relating to the actual loads acting on the primary structural members of tankers and bulk carriers. During this study, we proposed the following methodology. Design sea states that closely resemble the actual sea states which are considered to be the most severe for hull structures. Find practical estimation methods for the design sea states by parametric studies using the results of series calculations on representative tankers and bulk carriers. Find practical estimation methods for design regular waves which will result in the same level of stresses as those induced in irregular waves under the design sea states. We also briefly introduced some practical estimation methods for the design loads, such as ship motions, accelerations, hull-girder bending moments, and hydrodynamic pressures that are induced under design regular waves. The findings in this study have been summarized and implemented in the new design standards for tanker and bulk carrier structures.Updated from the Japanese original which won the 2003 SNAJ prize (J Soc Nav Archit Jpn 2002; 191:195–207; 2002; 191:208–220; and 2002; 192:723–733) 相似文献
120.
Nobuyoshi?FukuchiEmail author Changhong?Hu 《Journal of Marine Science and Technology》2004,8(4):177-184
In order to prevent the spread of marine compartment fires, it is necessary to understand the governing factors or characteristics of fire-spread phenomena. We present a pseudofield model approach to this problem. We first described a field model of turbulent heat convection based on a standard k – turbulence model. Two-dimensional numerical simulations of a two-linked compartment fire were carried out in order to predict the turbulent convection flow induced by the heat released from the fire. Then a more complicated fire-spread problem of multilinked compartment fires was analyzed by means of a zone model, in which the amounts of oxygen consumption and gas generation were solved by a gas-balance equations system. The effect of threshold conditions on fire propagation and the effect of the thickness of the heat insulation were investigated with numerical simulations. 相似文献