TRW plasma wave experiment for the IMP-H mission

The IMP-H plasma wave experiment is designed to extend knowledge of wave-particle interactions in the disturbed cislunar region, the distant geomagnetic tail, the upstream solar wind, and the flanks of the magnetosheath-shock interface. It is expected to identify plasma instabilities, study particle acceleration and heating at collisionless shocks and other discontinuities, analyze turbulent conductivity and field line merging, and provide new information on dissipation processes for suprathermal particles. Instrumentation for the plasma wave experiment is designed to measure local electric and magnetic field oscillations over the frequency range 10 Hz to 100 kHz. A 24 inch electric dipole, a 7 inch diameter air core search coil, and the associated preamplifiers are mounted on a spacecraft counterweight boom. The frequency range of 10 Hz to 100 kHz for both E and B is processed using an eight-channel spectrum analyzer located in the instrument main-body package (a standard IMP trapezoidal module, 3 inches high). Electric fields as small as 10-100 microvolts/meter and magnetic signals as small as 1-3 milligamma will be detected

Wear rate-state interactions within a multi-component system : a study of a gearbox accelerated life testing platform

The degradation process of complex multi-component systems is highly stochastic in nature. A major side effect of this complexity is that components of such systems may have unexpected reduced life and faults and failures that decrease the reliability of multi-component systems in industrial environments. In this work we provide maintenance practitioners with an explanation of the nature of some of these unpredictable events, namely the degradation interactions that take place between components. We begin by presenting a general wear model where the degradation process of a component may be dependent on the operating conditions, the component’s own state, and the state of the other components. We then present our methodology for extracting accurate health indicators from multi-component systems by means of a time-frequency domain analysis. Finally we present a multi-component system degradation analysis of experimental data generated by a gearbox accelerated life testing platform. In so doing, we demonstrate the importance of modelling the interactions between the system components by showing their effect on component lifetime reduction

A diagnostics and prognostics framework for multi-component systems with wear interactions: application to a gearbox-platform

We present a novel framework for diagnostics and prognostics for multi-component systems with wear interaction between components. The principal elements of this framework are: health-state indicator extraction using signal-processing; clustering of wear phases using a Gaussian mixture model; a stochastic multivariate wear model; and prediction of the remaining-useful-life of components using particle-filtering. These elements of the framework are illustrated and verified using an experimental platform that generates real data. Our diagnostics study shows that different clusters not only indicate the wear-state, but also the wear-rate of the components. Furthermore, our prognostics study shows that the wear-interaction between components has an significant impact in predicting the remaining-useful-life for components. Thus, we demonstrate, for prognostics and health management, the importance of modeling wear interactions in the prognostic process of multi-component systems

The Strategic Exploitation of Limited Information and Opportunity in Networked Markets

This paper studies the effect of constraining interactions within a market. A model is analysed in which boundedly rational agents trade with and gather information from their neighbours within a trade network. It is demonstrated that a trader’s ability to profit and to identify the equilibrium price is positively correlated with its degree of connectivity within the market. Where traders differ in their number of potential trading partners, well-connected traders are found to benefit from aggressive trading behaviour.Where information propagation is constrained by the topology of the trade network, connectedness affects the nature of the strategies employed

National cross-sectional study of the sociodemographic characteristics of Aotearoa New Zealand's regulated health workforce pre-registration students: A mirror on society?

Objectives To provide a sociodemographic profile of students enrolled in their first year of a health professional pre-registration programme offered within New Zealand (NZ) tertiary institutions. Design Observational, cross-sectional study. Data were sought from NZ tertiary education institutions for all eligible students accepted into the first ar of a health professional programme for the 5-year period 2016-2020 inclusive. Variables of interest: gender, citizenship, ethnicity, rural classification, socioeconomic deprivation, school type and school socioeconomic scores. Analyses were carried out using the R statistics software. Setting Aotearoa NZ. Participants All students (domestic and international) accepted into the first ar of a health professional programme leading to registration under the Health Practitioners Competence Assurance Act 2003. Results NZ's health workforce pre-registration students do not reflect the diverse communities they will serve in several important dimensions. There is a systematic under-representation of students who identify as Māori and Pacific, and students who come from low socioeconomic and rural backgrounds. The enrolment rate for Māori students is about 99 per 100 000 eligible population and for some Pacific ethnic groups is lower still, compared with 152 per 100 000 for NZ European students. The unadjusted rate ratio for enrolment for both Māori students and Pacific students versus Other' students is approximately 0.7. Conclusions We recommend that: (1) there should be a nationally coordinated system for collecting and reporting on the sociodemographic characteristics of the health workforce pre-registration; (2) mechanisms be developed to allow the agencies that fund tertiary education to base their funding decisions directly on the projected health workforce needs of the health system and (3) tertiary education funding decisions be based on Te Tiriti o Waitangi (the foundational constitutional agreement between the Indigenous people, Māori and the British Crown signed in 1840) and have a strong pro-equity focus

Near-optimal modified base stock policies for the capacitated inventory problem with stochastic demand and fixed cost

In this study, we investigate a single-item, periodic-review inventory problem where the production capacity is limited and unmet demand is backordered. We assume that customer demand in each period is a stationary, discrete random variable. Linear holding and backorder cost are charged per unit at the end of a period. In addition to the variable cost charged per unit ordered, a positive fixed ordering cost is incurred with each order given. The optimization criterion is the minimization of the expected cost per period over a planning horizon. We investigate the infinite horizon problem by modeling the problem as a discrete-time Markov chain. We propose a heuristic for the problem based on a particular solution of this stationary model, and conduct a computational study on a set of instances, providing insight on the performance of the heuristic. © 2014 World Scientific Publishing Co