Perspectives on the commercial development of landing gear health monitoring systems

The development of health monitoring technologies for aerospace systems creates a number of challenges for the community of engineers and technical specialists as they seek to integrate the technology into well defined working practices. These challenges do not just extend to the technical, but require a number of commercial questions to be addressed. It is of vital importance, that there is a clearly identified need for aerospace health monitoring, both from a technological and commercial viewpoint. If these needs cannot be identified, then any attempt for marketing health monitoring as a necessary future technological requirement is doomed for failure. Health monitoring technology will need to either deliver significant cost saving benefits to the aircraft operator or demonstrated increases in aircraft safety. The objective of the paper is to provide an assessment of the commercial benefits and development of aircraft landing gear health monitoring. The commercial need and challenges for health monitoring systems are explored in this paper within the context of a changing aerospace maintenance industry and the role in which new systems technology will play. The key findings of the research study are that within the aerospace industry there is a desired paradigm shift within aircraft maintenance towards offering maintenance systems with predictive capabilities. This maintenance revolution will not just incorporate new technologies, but will result in aircraft maintenance packages tailored towards individual customer requirements. The study illustrates the state-of-the-art in health monitoring currently restricts aerospace integration and a number of key technical and commercial issues need to be addressed. Predictive health monitoring offers a variety of commercial benefits for maintenance providers, aircraft operators and manufacturers. However, in order for these benefits to be realised increased transparency in maintenance related information is required between these key players.     

Car-deficit households: determinants and implications for household travel in the U.S.

Transportation - In the U.S., households with less than one car per driver (auto-deficit households) are more than twice as common as zero-vehicle households. Yet we know very little about these...     

Residential relocations and changes in vehicle ownership

While the relationship between automobile ownership and the built environment is well established, less is known about how household relocations—specifically, moves between urban and suburban geographies—affect the likelihood of owning an automobile. Using the Panel Study of Income Dynamics and a refined neighborhood typology, I examine the relationship between inter-geography moves and transitions into and out of carlessness. Results suggest that among low-income households, urban-to-suburban movers have an increased likelihood of becoming car owners; those moving in the “opposite” direction—from suburban to urban neighborhoods—show a high propensity to transition into carlessness. Patterns among higher-income households, while similar, are more pronounced. In particular, higher-income carless households that make urban-to-suburban moves are far more likely to become car owners than their low-income counterparts. This highlights the ease with which higher-income households adjust their car ownership levels to suit their post-move neighborhoods. Higher-income suburban-to-urban movers are also more likely to transition into carlessness than low-income households. Importantly, however, only households at the bottom end of the “higher income” distribution have an increased propensity to become carless; suburban-to-urban movers with more financial resources maintain vehicle ownership rates similar to households that remain in the suburbs.

     

Port competitiveness from the users' perspective: An analysis of major container ports in China and its neighboring countries

The objective of this paper is to explore the relative importance of factors that determine container port competitiveness from the users' perspective. Three groups of port users – shipping liners, forwarders and shippers – are considered in this paper. The importance of the various factors is determined on the basis of survey results from the industry experts and then obtained via the analytic hierarchy process (AHP). Furthermore, we use the results to evaluate ports in Mainland China, Hong Kong and other Asian cities. Given our results, operators of our sample ports could benchmark their performance with their competitors and identify the areas that they need to improve.     

Scaled vehicle tire characteristics: dimensionless analysis

This article demonstrates the use of dimensional analysis for scaled vehicle tires. The motivation for this approach is the understanding of realistic nonlinear tire behavior in scaled vehicle control studies. By examining the behavior of vehicle tires within a dimensionless framework, several key tire parameters are developed that allow for an appropriate relationship between full-sized tires and scaled tires. Introducing these scalings into vehicle dynamics studies allows for the development of scaled vehicles that have a high degree of dynamic similitude with full-sized vehicles, but are safer and more economical testbeds on which to develop experimental control strategies. Experimental data are used to compare the nonlinear characteristics for sets of scaled and full-sized tires. Finally, design of a scaled vehicle based on tire characteristics is demonstrated.     

New Zealand Advances in Performance-Based Seismic Design

This paper provides a summary of the objectives and principles which underpin the 2004 edition of the New Zealand earthquake design standard, AS/NZS 1170 Part 5. As with many modern earthquake design standards, the New Zealand earthquake design standard recognizes that earthquake resistant design that only addresses life safety goals without addressing both operational continuity of essential facilities and damage control, falls short of public expectations. Such standards not longer meet societal expectations. The paper outlines how these issues have been addressed within New Zealand, and some of the issues addressed when preparing appendices to the standard to provide guidance for materials standard writers to ensure consistency with the proposed approach. Recognizing the significance of non-structural components and parts of buildings in both damage control and operational continuity has been an important step forward in attaining the performance levels required.     

International Learning Pathways for Coastal Professionals: A Japan–UK Example

This article reports on the Learning Exchange Programme (LEP) model of capacity building for Integrated Coastal Management (ICM) professionals. The LEP model of capacity building involves international group-based exchange visits during which a structured program of experiential learning events is undertaken to meet specific capacity gaps. An application of the LEP model in Japan and the United Kingdom is presented and evaluated, which shows that while refinements could be identified, a group-based, tailored exchange model focused on filling specific capacity gaps is an effective model of capacity building for ICM.     

The return on investment for taxi companies transitioning to electric vehicles

We study whether taxi companies can simultaneously save petroleum and money by transitioning to electric vehicles. We propose a process to compute the return on investment of transitioning a taxi corporation’s fleet to electric vehicles. We use Bayesian data analysis to infer the revenue changes associated with the transition. We do not make any assumptions about the vehicles’ mobility patterns; instead, we use a time-series of GPS coordinates of the company’s existing petroleum-based vehicles to derive our conclusions. As a case study, we apply our process to a major taxi corporation, Yellow Cab San Francisco (YCSF). Using current prices, we find that transitioning their fleet to battery electric vehicles and plug-in hybrid electric vehicles is profitable for the company. Furthermore, given that gasoline prices in San Francisco are only 5.4 % higher than the rest of the United States, but electricity prices are 75 % higher; taxi companies with similar practices and mobility patterns in other cities are likely to profit more than YCSF by transitioning to electric vehicles.     

Inland boundary determinations for coastal management purposes—an ecological systems approach to requirements of the federal coastal zone management Act of 1972

Abstract

An analysis of ecological systems that both sustain and are sustained by coastal waters provides the key to a biophysical procedure for delineating inland coastal management boundaries. This analysis entails two basic tasks: (1) mapping the ecosystems that compose coastal waters and adjacent areas, and (2) charting sustaining flows among these systems. The resulting boundary encompasses all environments of coastal waters (subaqueous areas containing a measurable quantity of seawater) and all shore‐lands (either emergent or submergent environments that interchange sustaining materials, energy, or biota with coastal waters). As this biophysical procedure depends on the precise location of, and functional transfers among, coastal ecosystems, it provides a means both for assessing the consequences of human actions and for establishing a landward boundary for a management program. Alternative boundaries not based on locations and operations of coastal ecosystems would probably be either arbitrary or of undue extent, nor would such “alternative”; boundaries be an integral part of an ongoing management process.     

Estimating the marginal cost of railway track renewals using corner solution models

Economic theory advocates marginal cost pricing for efficient utilisation of transport infrastructure. A growing body of literature has emerged on the issue of rail marginal infrastructure wear and tear costs, but the majority of the work is focused on costs for infrastructure maintenance. Railway track renewals are a substantial part of an infrastructure manager’s budget, but in disaggregated statistical analyses they cause problems for traditional regression models since there is a piling up of values of the dependent variable at zero. Previous econometric work has sought to circumvent the problem by aggregation in some way. In this paper we instead apply corner solution models to disaggregate (track-section) data, including the zero observations. We derive track renewal cost elasticities with respect to traffic volumes and in turn marginal renewal costs using Swedish railway renewal data over the period 1999–2009. This paper is the first attempt in the literature to apply corner solution models, and in particular the two-part model, to disaggregate renewal cost data in railways. It is also the first paper that we are aware of to report usage elasticities specifically for renewal costs and therefore adds important new evidence to the previous literature where there is a paucity of studies on renewals and considerable uncertainty over the effects of rail traffic on renewal costs. In the Swedish context, we find that the inclusion of marginal track renewal costs in the track access pricing regime, which currently only reflects marginal maintenance costs, would add substantially to the existing track access charge. EU legislation requires that access charges reflect the ‘costs directly incurred as a result of operating the train service’, which should include a marginal renewal cost component. This change would also increase the cost recovery ratio of the Swedish infrastructure manager, thus meeting a policy objective of the national government.