Signal processor architecture for backscatter radars

Real time signal processing for backscatter radars which requires computational throughput and I/O rates is discussed. The operations that are usually performed in real time are highly repetitive simple accumulations of samples or of products of samples. The control logic does not depend on the values of the data and general purpose computers are not required for the initial high speed processing. The implications of these facts on the architectures of preprocessors for backscatter radars are explored and applied to the design of the Radar Signal Compender

Generalized Multiplicative Domains and Quantum Error Correction

Given a completely positive map, we introduce a set of algebras that we refer to as its generalized multiplicative domains. These algebras are generalizations of the traditional multiplicative domain of a completely positive map and we derive a characterization of them in the unital, trace-preserving case, in other words the case of unital quantum channels, that extends Choi's characterization of the multiplicative domains of unital maps. We also derive a characterization that is in the same flavour as a well-known characterization of bimodules, and we use these algebras to provide a new representation-theoretic description of quantum error-correcting codes that extends previous results for unitarily-correctable codes, noiseless subsystems and decoherence-free subspaces.Comment: 14 page

Heat flow calorimeter

Heat flow calorimeter devices are used to measure heat liberated from or absorbed by an object. This device is capable of measuring the thermal output of sealed nickel-cadmium batteries or cells during charge-discharge cycles. An elongated metal heat conducting rod is coupled between the calorimeter vessel and a heat sink, thus providing the only heat exchange path from the calorimeter vessel itself

Thrust reverser for a long duct fan engine

A bypass duct outer cowl includes a fixed cascade disposed between axially spaced fixed cowl portions and a translatable cowl sleeve and blocker doors movably disposed on the respective radially outer and inner sides of the cascade. Actuation and linkage structure located entirely within the outer cowl provides for selectively moving the cowl sleeve rearwardly and rotating the blocker doors to a position across the bypass duct to cause the fan airflow to pass through the cascade in a thrust reversing manner

Optimal scheduling of reliability development activities

Probabilistic Safety Assessment and Management is a collection of papers presented at the PSAM 7 - ESREL '04 Conference in June 2004. The joint Conference provided a forum for the presentation of the latest developments in methodology and application of probabilistic and reliability methods in various industries. Innovations in methodology as well as practical applications in the areas of probabilistic safety assessment and of reliability analysis are presented in this six volume set. The aim of these applications is the optimisation of technological systems and processes from the perspective of a risk-informed safety management while also taking economic and environmental aspects into account. The joint Conference in particular achieved an enhanced communication, the sharing of experience and integration of approaches not only among the various industries but also on a truly global basis by bringing together leading experts from all over the world. Over the last four decades, contemporary researchers have continuously been working to provide modern societies with a systematic, self-consistent and coherent framework for making decisions on at least one class of risks, those stemming from modern technological applications. Most of the effort has been spent in developing methods and techniques for assessing the dependability of technological systems, and assessing or estimating the levels of safety and associated risks. A wide spectrum of engineering, natural and economic sciences has been involved in this assessment effort. The developments have moved beyond research endeavours, they have been applied and utilised in real socio-technical environments and have become established - while modern technology continues to present new challenges and to raise new questions. Consequently, Probabilistic Safety Assessment and Management covers both well-established practices and open issues in the fields addressed by the Conference, identifying areas where maturity has been reached and those where more development is needed. The papers reflect a wide variety of disciplines, such as principles and theory of reliability and risk analysis, systems modelling and simulation, consequence assessment, human and organisational factors, structural reliability methods, software reliability and safety, insights and lessons from risk studies and management/decision making. A diverse range of application areas are represented including aviation and space, chemical processing, civil engineering, energy, environment, information technology, legal, manufacturing, health care, defence, transportation and waste management

Macroeconomic Shocks, Job Security and Health: Evidence from the Mining Industry

How do exogenous changes in the macroeconomic environment affect workers’ perceived job security, and consequently, their mental and physical health? To answer this question, we exploit variation in world commodity prices over the period 2001-17 and analyse panel data that includes detailed classifications of mining workers. We find that commodity price increases cause increases in perceived job security, which in turn, significantly and substantively improve the mental health of workers. In contrast, we find no effects on physical health. Our results imply that the estimated welfare costs of recessions are much larger when the effects of job insecurity, and not only unemployment, are considered

A viscous-inviscid interactive compressor calculations

A viscous-inviscid interactive procedure for subsonic flow is developed and applied to an axial compressor stage. Calculations are carried out on a two-dimensional blade-to-blade region of constant radius assumed to occupy a mid-span location. Hub and tip effects are neglected. The Euler equations are solved by MacCormack's method, a viscous marching procedure is used in the boundary layers and wake, and an iterative interaction scheme is constructed that matches them in a way that incorporates information related to momentum and enthalpy thicknesses as well as the displacement thickness. The calculations are quasi-three-dimensional in the sense that the boundary layer and wake solutions allow for the presence of spanwise (radial) velocities

High-resolution single-pulse studies of the Vela Pulsar

We present high-resolution multi-frequency single-pulse observations of the Vela pulsar, PSR B0833-45, aimed at studying micro-structure, phase-resolved intensity fluctuations and energy distributions at 1.41 and 2.30 GHz. We show that the micro-pulse width in pulsars has a period dependence. Like individual pulses, Vela's micro-pulses are highly elliptically polarized. There is a strong correlation between Stokes parameters V and I in the micro-structure. We show that the V/I distribution is Gaussian with a narrow width and that this width appears to be constant as a function of pulse phase. The phase-resolved intensity distributions of I are best fitted with log-normal statistics. Extra emission components, i.e.``bump'' and ``giant micro-pulses'', discovered by Johnston et al.(2001) are also present at 2.3 GHz. The bump component seems to be an extra component superposed on the main pulse profile but does not appear periodically. The giant micro-pulses are time-resolved and have significant jitter in their arrival times. Their flux density distribution is best fitted by a power-law, indicating a link between these features and ``classical'' giant pulses as observed for the Crab pulsar, (PSR B0531+21), PSR B1937+21 and PSR B1821-24. We find that Vela contains a mixture of emission properties representing both ``classical'' properties of radio pulsars (e.g. micro-structure, high degree of polarization, S-like position angle swing, orthogonal modes) and features which are most likely related to high-energy emission (e.g. extra profile components, giant micro-pulses). It hence represents an ideal test case to study the relationship between radio and high-energy emission in significant detail.Comment: accepted for publication in MNRAS (11 pages, 10 figures