A risk model for the operation of container vessels

Commercial shipping of containerized goods involves certain risks for human safety and environment. In order to actively manage these risks, they must be identified, analyzed, modeled, and quantified. This requires a systematical analysis of design and operation of container vessels. Within the EU-funded research project SAFEDOR, a Formal Safety Assessment has been applied to establish the current safety level of generic container ships and to identify potential cost-effective risk control options. This paper describes a structured approach to develop the underlying high-level risk model. It is structured as risk contribution tree consisting of a series of fault trees and event trees for the major accident categories. Statistical analysis of casualty data is used to estimate the probability of occurrence. Finally, the summation overall individual risk contributions yields the current risk pro file for the operation of container vessels is presented as FN-curve.     

传感器推动汽车环保变革

汽车业未来将走向何方?混合动力还是乙醇燃料?天然气还是氢气?或者是以上全部?人们对此争论不休.但有一点毋庸置疑,就是随着电子技术的发展,未来的汽车将日益与高科技接轨.     

Optimal slack time for timed transfers at a transit terminal

At transit terminals where two routes interchange passengers, total system costs may be reduced by allowing some “slack” time in the vehicle schedules to decrease the probability of missed connections. Transfer cost functions are formulated and used to determine optimal slack time for simple systems with transfers between one bus route and one rail line. Some analytic results are derived for empirical discrete and Gumbel distributions of bus arrival times. Relations between the optimal slack times and headways, transfer volumes, passenger time values, bus operating costs, and standard deviations of bus and train arrivals are also developed numerically using normally distributed arrivals. However, the proposed numerical approach can optimize slack times for any observed arrival distributions. The results provide some guidelines on desirable slack times and show that schedule coordination between the two routes is not worth attempting when standard deviations of arrivals exceed certain levels. Possible extensions of this work are suggested in the last section.     

Assessing the Potential for Surf Break Co-Management: Evidence from New Zealand

The involvement of surfers in surf break co-management initiatives may assist local authorities in providing for surf breaks and develop community stewardship. This research involved a comparative case study of the Auckland and Otago regions in New Zealand to assess the potential, and identify key ingredients, for successful surf break co-management. An online survey of surf break users (n = 181) and qualitative interviews (n = 16) considered the potential voluntary involvement of surfers, the role of local authorities and types of approach to surf break co-management. Findings indicate a level of support from a proportion of surfers to be involved and stress the need for local authorities to provide a supporting policy response. A local-scale co-management approach, similar to National Surfing Reserves in New South Wales, Australia, is considered more likely to produce positive outcomes compared to the involvement of surf break interests in coastal-wide co-management approaches.     

Marine Shoreline Management—A 35-Year Evaluation of Outcomes in San Juan County,Washington, US

In 1976, Washington became the first state to implement the federal Coastal Zone Management Act (CZMA) primarily through the 1971 WA Shoreline Management Act (SMA). However, there has been little effort in Washington to evaluate outcomes of shoreline protection programs post SMA. In 2006–2008, we characterized shoreline conditions in San Juan County over three time periods spanning pre and post SMA and engaged community members to improve effectiveness of shoreline protection. We found modest improvements in forest retention on marine shorelines between pre and post 1977, but few other improvements through time. While we could not measure shoreline construction rates, construction practices for shore armor and overwater structures (docks) have changed very little, despite the increased regulatory standards. The vast majority of shore armor constructed post SMA occurred without mandatory county or state permits likely due to: widespread perception that permits were unnecessary and that permit standards were arbitrary and inconsistently applied; poor understanding of shoreline ecology by community members; lack of county or state enforcement authority and shoreline monitoring programs; and poor permit tracking systems.     

应用碟片激光器和光学扫描仪进行遥控焊接

采用YAG激光器进行固体焊接，已成为汽车制造过程中一项成熟可靠的工艺。该项工艺现广泛用于车身和车架制造、传动系统制造、车座制造和其它领域。     

An algorithm for the combined distribution and assignment problem

Much interest has recently been shown in the combination of the distribution and assignment models. In this paper we adopt a generalized Benders' decomposition to solve this combined problem for a system optimized assignment with linear link costs and explicit capacity constraints on link flows. The master problem which is generated is used to show that the combined problem can be viewed as a modified distribution problem, of gravity form, with a minimax instead of a linear objective function. An algorithm for solving the master problem is discussed, and some computational results presented.     

Analyzing aviation safety: Problems,challenges, opportunities

This paper reviews the economic literature relating to aviation safety; analyzes the safety record of commercial passenger aviation in the United States and abroad; examines aviation security as a growing dimension of aviation safety; and identifies emerging issues in airline safety and challenges for aviation safety research. Commercial airline safety has improved dramatically since the industry's birth over a century ago. Fatal accident rates for large scheduled jet airlines have fallen to the level where (along many dimensions) aviation is now the safest mode of commercial transportation. However, safety performance has not been evenly distributed across all segments of commercial aviation, nor among all countries and regions of the world. The finding that developing countries have much poorer safety records has been a persistent conclusion in aviation safety research and continues to be the case. Unfortunately, operations data are not available for many of the airlines that experience fatal accidents, so it is not possible to calculate reliable fatality rates for many segments of the worldwide aviation industry. Without more complete information, it will likely be difficult to make substantial improvements in the safety of these operations. Challenges to improving aviation security include: how much to focus on identifying the terrorists as opposed to identifying the tools they might use; determining how to respond to terrorist threats; and determining the public versus private roles in providing aviation security. The next generation of safety challenges now require development and understanding of new forms of data to improve safety in other segments of commercial aviation, and moving from a reactive, incident-based approach toward a more proactive, predictive and systems-based approach.     

Measuring inefficiency in the Norwegian bus industry using multi-directional efficiency analysis

This paper deals with methods of measuring and analyzing efficiency in the transport industry. The aim of the paper is to introduce and demonstrate the advantages of Multi-directional Efficiency Analysis (MEA) in the case of cost data with limited substitution possibilities. For this purpose we reconsider the Norwegian bus data that has previously been analyzed using econometric models and Data Envelopment Analysis; Jørgensenet al. (1995, 1997) and Odeck and Alkadi (2001). It is shown how, using MEA, it becomes possible to disaggregate inefficiency into different components corresponding to different types of cost generating variables and thereby providing both managers of the bus companies and policy makers with more detailed information on possible improvements in performance.     

Exploring stability and change in transport systems: combining Delphi and system dynamics approaches

Transport is a vast and complex socio-technical system, and despite a clear need to reduce dependence on fossil fuels due to undesirable environmental impacts, it is largely locked into business-as-usual. Systems approaches are a useful way to help make sense of multiple competing influences which may be simultaneously driving change and supporting the status quo. This paper applies qualitative system dynamics modelling to help interpret the results of a Delphi study into global transport transitions, involving 22 international experts in various aspects of transport. The main contribution of the paper is its exploration of the use of system dynamics (SD) modelling to interpret the Delphi findings. SD modelling was used to reveal and elucidate the causal arguments put forward by the expert panel about the factors driving business-as-usual, the factors creating barriers to more sustainable transport systems, and the drivers of change. The SD model is used to explore and expose the key causal patterns at play, and how these interact to both support and hinder change. The resulting model shows the complex, interdependent dynamics involved in supporting the status quo. Even at the relatively high level of analysis reported here, the model is useful in revealing interdependencies between parts of the system, where change in one part may well have knock-on effects elsewhere in the system. In particular the model reveals the strong reinforcing loops that act to minimise the impact of change drivers and thus retain the dominance of automobility. The result is a system that is highly dependent on the continued existence of key reinforcements such as policies that subsidise fossil fuels. From a methodological perspective, the outcomes of the Delphi study provided a rich source of qualitative material which was highly suitable for developing a system dynamics model.