公务艇技术经济性评价指标分析及论证

根据公务艇的自身特性,参照GB11697—89的相关规定,建立了一套适用于公务艇技术经济性能分析的评价指标体系和计算方法。实践证明：此评价指标体系可对公务艇的技术经济性进行有效分析,并评估其是否达到目标要求,便于指导今后的设计工作;同时,此评价指标体系也是对有关船舶与海洋结构物性能水平等级评价体系国家标准的有益补充。     

Shipper's councils: role and responsibility—a western view

Traditionally, liner markets have been seen as dominated by conferences on the seller side, facing small, unorganized shippers onn the buyers' side. This perceived asymmetry has greatly influenced conference legislation in North America (and more recently in the E.U.) and it has been deemed essential that government should regulate conference activities in order to curb any abuse of 'conference power'. In this view, shipowners and shippers are adversaries engaged in a zero-sum battle over transport costs rather than potential or actual partners in global distribution systems. This paper suggests that in today's global markets much can be achieved by cooperationn in the development of logistics systems and that shipowners and shippers may have much to gain from such cooperative alliances. A survey of shippers' councils in 1991-1992 demonstrates the diversity and increasing sophistication of many national shippers' councils, which devote themselves to the task of improving markets through education and the legislative process. The situation in the U.S.A. is different: for legal reasons, conventional shippers' councils do not exist. Instead, 'shippers' associations' play a commercial role in liner markets. It is suggested that European style shippers' councils can and should play an important role in the development and formulation of policies for internatinal liner markets. Such participation requires a cooperative industry environment quite different from the traditional adversarial approach, which is ill suited to global trade and logistics alliances.     

Rogue ships—a shipowner's view

The paper, first of all, examines what a 'rogue ship' is and then moves on to the various practical solutions as to how to deal with the problem. There is no one single answer but the author believes that it is in the interest of society in general to get rid of these ships.     

浮式生产储油装置(FPSO)技术经济评价指标分析及论证

文章简述了一种特殊船型--浮式生产储油装置的特点、功能及其技术经济指标的选取.针对这种特殊船型的实际工况,给出相应的技术经济评价指标,并对传统国标(GB11697-89)提出了修正意见.实践表明,修正后的技术经济指标评价体系应用于FPSO的评价是适用的和可靠的.     

Scantling optimization based on convex linearizations and a dual approach—Part II

The development of the LBR-5 “Stiffened Panels Software” is included in the development of a new design methodology to ease and to improve preliminary studies of naval structures and floating hydraulic structures. It allows, as of the first draft, an optimization of the scantling of the structure's constituent elements. The ultimate target is to link standard design tools (steel structure CAD, hull form, hydrostatic curves, floating stability, weight estimation, etc.) with a rational optimization design module and a minimum construction cost (or minimum weight) objective function. It is developed to be a user-oriented tool. The optimization module is composed of three basic modules (OPTI, CONSTRAINT and COST) and a group of sub-modules (in external databases). Among these the user selects a set of relevant sub-modules (i.e. geometrical and structural constraints). Since the present optimization deals with least construction costs (as objective function), and uses an explicit objective function (not empirical), the user must specify labor costs (unitary material costs, welding, cutting, etc.). This paper is the second part of a series of two articles. The previous paper focused on the ‘Module-Oriented Optimization’ methodology and on the rational constraints (Rigo, Marine Structures 2001). This paper presents the optimization algorithm based on convex linearization and a dual approach (OPTI module). It also includes the optimization of a FSO unit as a detailed example.     

运河通航:打造畅通平安线

千百年来,京杭大运河一直是中国重要的南北水上运输通道,从历史上的南粮北运、盐运通道,到现在的北煤南运干线以及防洪灌溉干流,这条古老的运河至今仍发挥着巨大的作用。1855年,由于黄河迁徙,运河被拦腰截断,形成了以黄河为界的南北两段运河。随着岁月变迁,南北两段运河     

Optimal ship tracking on a navigation route between two ports: a hydrodynamics approach

The optimal trajectory from Calcutta port to Mumbai port is charted for a tanker transshipping from the East coast to the West coast of India during rough weather. Rough weather is simulated over Indian seas using the state-of-the-art WAM numerical wave model (WAMDI Group in J Phys Oceanogr 18:1775–1810, 1988), assimilating satellite (IRS-P4) wind fields. These simulated wave fields and two-dimensional (2D) directional wave spectrum are an absolute representation of the irregular seaway. Hence, the same for the monsoon month of August 2000 formed the input basis for this study. Loss of ship speed due to the wave field (i.e., nonlinear motion of the tanker in waves) and associated sea-keeping characteristics in the seaway are estimated (Bhattacharya in Dynamics of marine vehicles, Wiley, New York, 1978). The approach adopted in this paper is unique in that it takes into account both voluntary and involuntary speed reductions of the ship. It helps in ship tracking by the optimum route using inverse velocity as the weight function for the path in an efficient way. Dijkstra’s algorithm [Numer Math 1(3):269–271, 1959] is applied in an iterative manner for determining the optimum track. The optimum track information has broad scope for use in modern shipping industry for obtaining safe and least-time routing by avoiding schedule delays with economic fuel consumption.     

Biological effects of Mississippi River nitrogen on the northern gulf of Mexico—a review and synthesis

The Mississippi River currently delivers approximately 1.82 Tg N year⁻¹ (1.3×10¹¹ mol N year⁻¹) to the northern Gulf of Mexico. This large input dominates the biological processes of the region. The “new” nitrogen from the river stimulates high levels of phytoplankton production which in turn support high rates of bacterial production, protozoan and metazoan grazing, and fisheries production. A portion of the particulate organic matter produced in the pelagic food web sinks out of the euphotic zone where it contributes to high rates of oxygen consumption in the bottom waters of the inner shelf, resulting in the development of an extensive zone of hypoxia each summer. In spite of the significance of this river system to the coastal ocean of the northern gulf, we do not have an adequate understanding of the inputs, processing and ultimate fates of river nitrogen. Here we review available literature on this important system and propose a conceptual model showing how biological processes evolve in the river plume between the point of discharge and the point where plume waters are fully diluted by mixing with oceanic water.     

Modeling oil spills in a river—lake system

A general model shell, ROSS3, is developed for simulating oil spills in complex river systems using techniques which have not been previously exploited in oil spill models. ROSS3's new approach has several advantages over the approach to model oil spills in the past: (a) The use of a time-varying boundary-fitted coordinate system that allows accurate accounting for complex river/lake boundary as well as the river boundary changes as its water levels fluctuate; (b) The ability to confine two-dimensional hydrodynamic computations to a limited river reach; (c) The ability to interactively layout the channel networks for setting up the model, define extra cross sections to increase the accuracy if needed, in addition to the traditional data entry and visualization interfaces.ROSS3 is a two-layer two-dimensional oip spill model that can simulate the mechanism of advection, horizontal diffusion, mechanical spreading, shoreline deposition, evaporation, dissolution, vertical mixing, resurfacing and sinking. In ROSS3 spilled oil may be a surface slick or suspended oil droplets, or a combination of both. Both free surface and ice cover conditions can be simulated. The flow of conditions can be varied and the unsteady flow model can be run within ROSS3 to simulate the flow conditions in both the river and the lake. The ice conditions can be added or removed from the model input using easy interactive procedures.     

A short-term adaptive forecasting model for BIFFEX speculation: a Box—Jenkins approach

There are numerous possible advantages to be gained from the accurate prediction of future movements in the Baltic Freight Index (BFI). Because of the difficulties inherent in long-range forecasting, however, the potential for such predictions to provide insight into the future state of the physical dry bulk market is perhaps limited. The greater accuracy of short-term forecasts, on the other hand, facilitates the development of a forecasting model form is justified by the inevitably continuous nature of futures market speculation. Such a model is developed through the application of the Box—Jenkins approach to time series analysis and forecasting. The methodology is presented and the resulting model is evaluated on the basis of objective measures of predictive power and by comparison with alternative forecasting models. Finally, the applicability of the model to the practice of BIFFEX speculation is assessed by judging its performance within a simulated BIFFEX trading environment.     

The theory and practice of a carrier's liability under the Athens Convention—the English experience

The effect of the regulation of a carrier's liability by the mandatory application of rules introduced by international convention are considered in the context of a review of the standard terms and conditions employed by major UK passenger carriers reacting to the Athens Convention 1974. It is hoped that by analysing the impact of the Athens Convention upon the British operators who still play a significant part in the international transport of passengers, that light will be shed on the response than can be expected from maritime carriers to the imposition of international convention jurisdiction generally.     

Beta comparisons across industries—a Water transportation industry perspective

This paper undertakes a comparative analysis of the stock market perception of risk in US listed water transportation companies and seven other main sectors, air transportation; rail transportation; trucks; electricity; gas; petroleum refining; and real estate over the period July 1984-June 1995. This is done by employing the Capital Asset Pricing Model (CAPM) to model the stock returns of each industry and hence compare their betas (systematic risk). Multiequation Regression Models are used for estimation. The findings suggest that the water transportation industry exhibits significantly lower market risk than the average stock and the rail transportation industry, significantly higher systematic risk than the real estate industry, while its systematic risk is insignificantly different from the rest of the industries. These results are useful to investors basing their decisions on relative market exposures to risk in different industries.     

学生考试成绩评价系统的设计与实现

利用计算初编程,采用难度指数(P)及区别度指数(R)等多种分析参数实现对学生考试成绩以及教师试卷质量的分析。为从学生对教学内容掌握情况及教师的教学情况两方面进行客观的教学评价提供了依据。     

Debt—equity conversion and port privatization

Port privatization has been perceived as an instrument for the improvement in port management operations and marketing, yet it also provides a major opportunity for public debt reduction by converting debt incurred in port development into equity or other assets. There are many different ways in which debt, particularly foreign debt, can be converted. It can be directly converted into equity, it can be swapped for other debt, converted into various portfolio investments or exchanged for future services or exports. In recent years, 'ecological' swaps have also been considered in which some debt is written off in return for improvements in environmental management. This paper reviews the reasons for port privatization, the different methods for port ownership financing, and the role debt-equity conversion could play in it.     

Understanding the ocean container market—a seven country study [1]

Carrier selection criteria have been an issue in carrier marketing since the 1970s. Investigator location and interest has usually limited customer surveys to one geographic market. Market characteristics—differing purchase and service characteristics—have led to model seperation in the studies undertaken and sample size has constrained most researchers to reporting results as though customers were homogeneous in their needs. This has resulted in price versus service debates with conflicting conclusions. This paper explores the differences in the importance of various ocean container carrier selection criteria on the North Atlantic route for discrete geographic and customer segments. The paper reviewss the carrier selection literature and notes that carrier selection research to date has generally suffered from one or more of three problems: (1) because the research has focused on criteria 'importance', it has not identified determinants of purchase behaviour, that is, the 'salience' of different criteria; (2) the research has had sample size problems leading to the need to assume that the market is homogeneous or, less acceptable, that importance ratings will identify usable segments via factor analysis; and (3) carrier perfomance evaluation in conjucation with determinant criteria has largely been ignored. The paper focused on the problems surrounding the second of these by evaluating the relative importance of various service attributes for different geographic and customer dimensions. The paper concludes that the market is definitely not homogeneous in its requirements of carriers and that different elements surface as important both in identifiable geographical markets and customer groups. It also draws a number of conclusions about carrier choice in future and the implications for academic research.     

Ship Scrapping and the environment—the buck should stop!

The Shipbreaking industry has always had a vague image of being 'dirty', 'hazardous' and 'environmatally unfriendly'. As world fleet ages, technology advances and regulations become more stringent, the incidence of shipbreaking activity is set to increase, accompanied by a dispersal of operations bases. The corresponding environmental impacts are, thus, also said to expand commensurately, in magnitude and extent. This coupled with the fact that the shipscrapping is an industry that has a tendency to be located on the shores of the developing countries makes it an environmental tinderbox. The primary reason for this being the lack strict marine environmental regulations in the third world. Neither is the issue addressed at the international forum. The paper addresses the possibilities of the environmental impact of shipscrapping activities. The fact that this part of the shipping industry remains absolutely unregulated, causes a potential detriment to the marine environment. Finally the paper highlights why and what needs to be done.     

Inland container terminal—function and rationale

Increasing commercial and recreational pressures on urban waterfront lands, growing demand by seaports for back-up areas and changes in cargo-distribution concepts have caused the relocation of several port functions and the establishment of inland container terminals.