Structural models for the analysis of traveler attitude-behavior relationships

Traveler attitudes and behavior have been shown to correlate in numerous previous studies. However, the correlation by itself leaves open the nature of the interrelationships between traveler attitudes and behavior. For example, attitudes could either cause or be caused by behavior. In fact, both options are concurrently possible. Structural equations are applied to a set of data gathered from Los Angeles central business district workers to ascertain the direction and nature of interrelationships between attitudes and behavior with respect to frequency of taking the bus to work. A mutual dependence between attitudes and behavior is demonstrated in the context of this dataset and behavioral choice situation; behavior and attitudes concurrently cause each other. In addition, it is found that two attitudinal components, perceptions of and affect toward a mode, function differently with respect to travel behavior.     

Geography and Coastal Management

This article presents an overview of the relationship between geography and coastal management. It explores the nature of geography as well as the geographical underpinnings of key notions within coastal management, in particular, “coast,” “conflict,” and “integration.” The article considers the integrated coastal management process and tracks the influence of geography on the development of the discipline's theory and practice, as well as its academic infrastructure. The article concludes that although geography both underpins and offers useful insights into coastal management, a challenge remains to explore in greater depth the benefits of applied geographical approaches to the management of coasts.     

Environmental improvement on Narragansett Bay as a result of section 312 implementation of the Federal Water Pollution Control Act

Abstract

Section 312 of the Clean Waters Act was implemented in 1980 and requires all vessels including recreational boats already equipped with Marine Heads (toilets) to install one of three types of USCG approved Marine Sanitation Devices. These regulations govern all lakes and coastal waters extending to the end of the U.S. territorial sea and is intended to prevent untreated effluent from reaching the marine environment. As provisions of the Clean Water Act are exempt from provisions of the National Environmental Policy Act, no Environmental Impact Statement was written concerning the impacts to the marine environment and the cost to the boating public. The study based on a small survey conducted on Narragansett Bay during the summer of 1980 develops several empirical models to estimate the total costs of MSD conversions. These estimates assume that all recreational boats longer than 21 feet were to comply with Section 312 regulations. Biological Oxygen Demand generated waste by both the resident and visiting fleets have also been estimated and costs per lbs. of BOD equivalent made. Based on these estimates the quantity of waste prevented from entering the receiving waters equals that of a community with less than 700 people. The capital investments of on‐board treatment approximates 30 ¢/gallon, nearly 1000 times the cost of treating municipal waste.     

A combined science and management framework for developing regional monitoring objectives

Abstract

Designing environmental monitoring programs to deal with widespread, subtle, and/or cumulative impacts on a regional basis is challenging. It requires a shift away from focusing primarily on individual point sources to a more regional perspective. It also necessitates involving scientists and managers together in a cooperative effort to establish priorities and articulate clear objectives. In our view, this objective‐setting task is neither a strictly scientific nor a strictly management activity. It depends on effective communication between scientists and managers but is confounded by differing perspectives, value systems, and behaviors. We present a conceptual framework to assist managers and scientists in this process. This is intended to structure such communication by helping to create a context that permits fruitful give‐and‐take between the two groups. We then describe a six‐part model for specifying the key elements of regional monitoring objectives.     

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.     

Experimental investigation of the strength and stability of submarine pressure hulls with and without artificial corrosion damage

A submarine may have to operate for a period of time with local corrosion damage in the pressure hull if a suitable repair method is unavailable or too expensive for implementation. This paper describes collapse tests on twenty ring-stiffened aluminium cylinders, which were conducted to study the effect of corrosion damage on hull strength and stability. Artificial hull thinning was found to reduce the collapse strength of experimental models through high local stresses in the corroded region, leading to early onset of yielding and inelastic buckling. Bending associated with the eccentricity due to one-sided thinning was found to further increase the local stresses in the hull. Overall collapse pressures were more severely affected by corrosion damage than interframe collapse pressures. The percentage reduction in overall collapse pressure, compared with intact experimental models, was found to be closely related to the percentage depth of thinning. The accuracy of conventional collapse pressure predictions for the experimental models was significantly better for intact than for corroded cylinders.     

一位现代主义者 访盖瑞·麦戈文

汽车设计师盖瑞·麦戈文(GerryMcGovern)的家坐落在无忧无虑的英国乡间,他对自己的这栋现代派宅子相当得意,特地邀我们上门拍摄他的最新杰作、路虎Evoque。车子和宅子本身一样,都停泊在不怎么稳当的斜坡上,两者如面包和果酱一般亲密无间。     

Emerging organizational values in shipping: Part 1. Crew stability

In this paper, Smith and Roggema examine the solutions emerging in answer to the growing concern in North European shipping companies to adapt to increasing competition and technological diversity and also to attract and retain suitably qualified seafarers. Part 1 describes a move from a situation of lack of stability of crew towards greater crew stability, whilst Part 2 discusses the redistribution of responsibility on board ship, encompassing a change from the caste-like division between officers and ratings and a more flexible division of functions and authority.