Ergonomics in the development and implementation of organisational strategy for sustainability

This is the first phase of an ergonomics study of sustainability in a rail organisation, particularly environmental sustainability. The main emphasis has been on the use of a qualitative approach to carry out in-depth consultation with those in influential and policy setting roles in the organisation, collecting and analysing perceptions on sustainability policy and related business processes. The study identified factors affecting implementation of policy on sustainability and these have been developed to produce a list of requirements for implementing the policy. The findings are valuable in understanding the range of attitudes, aspirations and perceived constraints, from the perspective of those in senior roles in the company, and development of a sustainability strategy for a rail infrastructure owner. There is need for wider consultation, both within the organisation and externally, to validate and refine the understanding of barriers to the implementation of the policy. The role of ergonomics in supporting the work on sustainability is discussed.

Practitioner Summary: The study collects in-depth views from senior managers on the challenges of implementing a policy on sustainability in a rail organisation. Outputs include a list of factors affecting implementation of policy and requirements for better implementation of policy in this area. Potential contributions of ergonomics to sustainability in organisational contexts are discussed.     

Self-reported discomfort when using commercially targeted virtual reality equipment in discomfort distraction

Commercially targeted virtual reality (VR) equipment is gaining popularity and might be a viable tool for pain distraction. This experimental research aimed to discover whether active distraction techniques (such as commercially targeted VR and video games) result in reduced subjective discomfort relative to passive distraction techniques. The study examined a healthy adult population who experienced an experimentally induced discomfort task. Participants were 27 adults, 14 females and 13 males. Participants completed four tasks, a baseline measure of physical discomfort, video clip distraction (passive distraction), video game distraction (active distraction) and exploring a VR world using an Oculus Rift head-mounted display (active distraction). In all four test conditions, participants were asked to sit on a chair holding their non-dominant leg at a height of approximately 30 cm from the floor, up to a maximum of 5 min. Counterbalancing of task order was conducted to reduce effects of participant fatigue. The participants indicated significantly reduced self-reported discomfort in the active distraction tasks when compared to the passive distraction tasks. While the findings demonstrate the effectiveness of a commercially targeted VR technology in increasing pain tolerance, the relative benefits of this technology over non-immersive video games are not apparent.     

Effect of κ-carrageenan on rheological properties, microstructure, texture and oxidative stability of water-in-oil spreads

The effect of κ-carrageenan concentration (0-7.5 g kg⁻¹) on the rheology, microstructure, texture and oxidative stability of water-in-oil (W/O) spreads (600 g fat kg⁻¹ emulsion) was examined over 60 days storage time. Results showed that increasing the κ-carrageenan concentration to 7.5 g kg⁻¹ significantly increased the viscosity of the aqueous phase (to 42.7 mPa s at 60 °C) resulting in gelation of the aqueous phase on cooling. The microstructure of the spreads was disrupted by higher levels of κ-carrageenan, resulting in a less homogeneous distribution of the aqueous phase. Melt temperature (where tan δ > 1) decreased significantly from 62 to 56.2 °C with increasing κ-carrageenan concentration from 0 to 7.5 g kg⁻¹. The firmness and the G′ at 6 °C for all samples were significantly increased after 60 days storage with only small effects due to κ-carrageenan levels. Oxidation of the fat phase was evident by the significant increases in peroxide values of all spreads on storage, with κ-carrageenan exhibiting no antioxidant behaviour. While increased κ-carrageenan levels modified the microstructure of W/O spreads in terms of the droplet size of the aqueous phase and its distribution few changes were evident in the continuous fat phase.     

Investigation of the mechanical and thermal fatigue properties of hybrid sol–gel coatings applied to AA2024 substrates

This research article reports on the response of various hybrid sol–gel materials when applied as coatings to pre-treated bare AA2024 substrates, to mechanical indentation and cyclic thermal stimuli, in order to determine their usefulness in aeronautical applications. Three groups of hybrid sol–gel-coated samples were prepared using various organosilanes and transition metal oxides. The characterization of the materials revealed that the presence of the organic functionalities, especially the methacrylate group, has a noticeable effect on the mechanical response of the hybrid coatings, in particular their flexibility. The presence of methacrylate group in the cured material gives it ability to flex which influenced the thermal fatigue characteristics of the coatings which are able to withstand the cyclic temperature regimes of 82 ± 3 to ?37 ± 3°C over 25 2 h cycles. This capability to maintain substrate protection is reflected in the corrosion resistance of the coatings as measured using electrochemical impedance spectroscopy and accelerated exposure testing. This result is important, as it shows that hybrid sol–gel materials can be used in applications where protecting a metal or ally substrate is paramount, especially in thermally volatile environments.     

Comparable efficacy of contingency management for cocaine dependence among African American, Hispanic, and White methadone maintenance clients.

Cocaine use is a significant problem among methadone maintenance clients. Contingency management (CM) is a reinforcement-based approach with demonstrated efficacy for reducing cocaine use. This study examines whether the efficacy of CM treatment for cocaine-dependent individuals receiving methadone maintenance for opioid dependence differs by ethnicity. Participants were 191 African American, Hispanic, and White cocaine-dependent methadone maintenance clients, randomly assigned to standard methadone treatment or standard methadone treatment plus CM for 12 weeks. Hispanic participants were younger, less educated, and reported fewer years of cocaine use than did African American and White participants and reported fewer years of heroin use than did African American participants. African American participants were less likely to report a history of psychiatric symptoms or treatment in comparison with Hispanic and White participants. While CM was associated with longer duration of continuous cocaine abstinence and a greater proportion of submitted urine samples negative for cocaine, ethnicity was not related to treatment outcomes, and there was no significant interaction between treatment and ethnicity. CM appears to be an efficacious treatment for cocaine dependence among methadone maintenance clients, regardless of ethnicity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maximum likelihood estimation of higher‐order integer‐valued autoregressive processes

Abstract. In this article, we extend the earlier work of Freeland and McCabe [Journal of time Series Analysis (2004) Vol. 25, pp. 701–722] and develop a general framework for maximum likelihood (ML) analysis of higher‐order integer‐valued autoregressive processes. Our exposition includes the case where the innovation sequence has a Poisson distribution and the thinning is binomial. A recursive representation of the transition probability of the model is proposed. Based on this transition probability, we derive expressions for the score function and the Fisher information matrix, which form the basis for ML estimation and inference. Similar to the results in Freeland and McCabe (2004) , we show that the score function and the Fisher information matrix can be neatly represented as conditional expectations. Using the INAR(2) specification with binomial thinning and Poisson innovations, we examine both the asymptotic efficiency and finite sample properties of the ML estimator in relation to the widely used conditional least squares (CLS) and Yule–Walker (YW) estimators. We conclude that, if the Poisson assumption can be justified, there are substantial gains to be had from using ML especially when the thinning parameters are large.     

Port Moresby

Port Moresby is the capital of Papua New Guinea. With a population of nearly 200 000 it is by far the largest city in the country. Officially called the National Capital District (NCD), it straddles a low range of coastal hills in the south-east corner of the New Guinea mainland. It is a city facing serious problems today. A narrow economic base, a lack of land suitable for development and a deteriorating law and order situation are compounded by very rapid growth. The proposed construction of a transisland highway this decade, connecting Port Moresby to the populous interior, would have a profound impact on the future of the city.     

MORA routing and capacity building in disruption-tolerant networks

Disruption-tolerant networks (DTNs) differ from other types of networks in that capacity is created by the movements of network participants. This implies that understanding and influencing the participants’ motions can have a significant impact on network performance. In this paper, we introduce the routing protocol MORA, which learns structure in the movement patterns of network participants and uses it to enable informed message passing. We also propose the introduction of autonomous agents as additional participants in DTNs. These agents adapt their movements in response to variations in network capacity and demand. We use multi-objective control methods from robotics to generate motions capable of optimizing multiple network performance metrics simultaneously. We present experimental evidence that these strategies, individually and in conjunction, result in significant performance improvements in DTNs.     

Feature Selection vs Theory Reformulation: A Study of Genetic Refinement of Knowledge-based Neural Networks

Expert classification systems have proven themselves effective decision makers for many types of problems. However, the accuracy of such systems is often highly dependent upon the accuracy of a human expert's domain theory. When human experts learn or create a set of rules, they are subject to a number of hindrances. Most significantly experts are, to a greater or lesser extent, restricted by the tradition of scholarship which has preceded them and by an inability to examine large amounts of data in a rigorous fashion without the effects of boredom or frustration. As a result, human theories are often erroneous or incomplete. To escape this dependency, machine learning systems have been developed to automatically refine and correct an expert's domain theory. When theory revision systems are applied to expert theories, they often concentrate on the reformulation of the knowledge provided rather than on the reformulation or selection of input features. The general assumption seems to be that the expert has already selected the set of features that will be most useful for the given task. That set may, however, be suboptimal. This paper studies theory refinement and the relative benefits of applying feature selection versus more extensive theory reformulation.     

Probing the cure of 13C labelled bisphenol A dicyanate ester in carbon fibre reinforced composites using solid state 13C NMR, SEM and FTIR

We report a study of the curing mechanism of ¹³C labelld bisphenol A dicyanate ester in the presence of a electrolytically surface treated XAS carbon fibre using several techniques – solid state ¹³C NMR, scanning electron microscopy (SEM) and diffuse reflectance FTIR. Comparison of the results obtained in pure matrices and solution shows that the resin undergoes the same reaction mechanism in both cases and forms the sym-triazine network structure in the composite. Received: 25 November 1996/Accepted: 23 January 1997