Solid motor diagnostic instrumentation

A review of typical surveillance and monitoring practices followed during the flight phases of representative solid-propellant upper stages and apogee motors was conducted to evaluate the need for improved flight diagnostic instrumentation on future spacecraft. The capabilities of the flight instrumentation package were limited to the detection of whether or not the solid motor was the cause of failure and to the identification of probable primary failure modes. Conceptual designs of self-contained flight instrumentation packages capable of meeting these reqirements were generated and their performance, typical cost, and unit characteristics determined. Comparisons of a continuous real time and a thresholded hybrid design were made on the basis of performance, mass, power, cost, and expected life. The results of this analysis substantiated the feasibility of a self-contained independent flight instrumentation module as well as the existence of performance margins by which to exploit growth option applications

Qualitative design and implementation of human-robot spatial interactions

Despite the large number of navigation algorithms available for mobile robots, in many social contexts they often exhibit inopportune motion behaviours in proximity of people, often with very "unnatural" movements due to the execution of segmented trajectories or the sudden activation of safety mechanisms (e.g., for obstacle avoidance). We argue that the reason of the problem is not only the difficulty of modelling human behaviours and generating opportune robot control policies, but also the way human-robot spatial interactions are represented and implemented. In this paper we propose a new methodology based on a qualitative representation of spatial interactions, which is both flexible and compact, adopting the well-defined and coherent formalization of Qualitative Trajectory Calculus (QTC). We show the potential of a QTC-based approach to abstract and design complex robot behaviours, where the desired robot's behaviour is represented together with its actual performance in one coherent approach, focusing on spatial interactions rather than pure navigation problems

Probing Z' gauge boson with the spin configuration of top quark pair production at future e−e+e^- e^+ linear colliders

We explore the effects of extra neutral gauge boson involved in the supersymmetric E6 model on the spin configuration of the top quark pair produced at the polarized e- e+ collider. Generic mixing terms are considered including kinetic mixing terms as well as mass mixing. In the off-diagonal spin basis of the standard model, we show that the cross sections for the suppressed spin configurations can be enhanced with the effects of the Z' boson through the modification of the spin configuration of produced top quark pair enough to be measured in the Linear Colliders, which provides the way to observe the effects of Z' boson and discriminate the pattern of gauge group decomposition. It is pointed out that the kinetic mixing may dilute the effects of mass mixing terms, and we have to perform the combined analysis.Comment: 19 pages including 5 figures, ReVTe

CP violating asymmetries in single top quark production at the Tevatron p pbar collider

Analytic expressions for the angular distributions of the $b$-quarks associated with single $t$-quark production in $p \bar p \to W^* \to t \bar b \to b \bar b W$ and of the leptons from the subsequent decay $W \to l\nu$ are obtained in the laboratory system. CP violation in the $t$-production vertex is assumed. Different angular and total cross section CP violating asymmetries are considered. Relations testing CP violation solely in the $t$-decay vertex are also obtained. A numerical analysis is performed in the MSSM with a CP violating phase of the trilinear coupling $A_{\tilde t}$. The asymmetries are typically of the order $10^{-3}$ - $10^{-4}$.Comment: The numerical results are corrected and some changes that meet the requirements of Phys. Rev. D are mad

Linear sampling method for identifying cavities in a heat conductor

We consider an inverse problem of identifying the unknown cavities in a heat conductor. Using the Neumann-to-Dirichlet map as an input data, we develop a linear sampling type method for the heat equation. A new feature is that there is a freedom to choose the time variable, which suggests that we have more data than the linear sampling methods for the inverse boundary value problem associated with EIT and inverse scattering problem with near field data

Financial Information Mediation: A Case Study of Standards Integration for Electronic Bill Presentment and Payment Using the COIN Mediation Technology

Each player in the financial industry, each bank, stock exchange, government agency, or insurance company operates its own financial information system or systems. By its very nature, financial information, like the money that it represents, changes hands. Therefore the interoperation of financial information systems is the cornerstone of the financial services they support. E-services frameworks such as web services are an unprecedented opportunity for the flexible interoperation of financial systems. Naturally the critical economic role and the complexity of financial information led to the development of various standards. Yet standards alone are not the panacea: different groups of players use different standards or different interpretations of the same standard. We believe that the solution lies in the convergence of flexible E-services such as web-services and semantically rich meta-data as promised by the semantic Web; then a mediation architecture can be used for the documentation, identification, and resolution of semantic conflicts arising from the interoperation of heterogeneous financial services. In this paper we illustrate the nature of the problem in the Electronic Bill Presentment and Payment (EBPP) industry and the viability of the solution we propose. We describe and analyze the integration of services using four different formats: the IFX, OFX and SWIFT standards, and an example proprietary format. To accomplish this integration we use the COntext INterchange (COIN) framework. The COIN architecture leverages a model of sources and receivers’ contexts in reference to a rich domain model or ontology for the description and resolution of semantic heterogeneity.Singapore-MIT Alliance (SMA

Angular Correlations in Top Quark Pair Production and Decay at Hadron Colliders

We show how to observe sizable angular correlations between the decay products of the top quark and those of the anti-top quark in top quark pair production and decay at hadron colliders. These correlations result from the large asymmetry in the rate for producing like-spin versus unlike-spin top quark pairs provided the appropriate spin axes are used. The effects of new physics at production or decay on these correlations are briefly discussed.Comment: 34 pages, revtex, including 12 uuencoded postscript figure

Transverse Polarization of Top Quarks Produced at a Photon-Photon Collider

At future $\gamma \gamma$ colliders copious production of $t \bar{t}$ pairs is possible. This would allow a detailed investigation of the interactions involving the top quark. We propose some orrelations which are sensitive to $t \bar{t}$ final state interactions and we compute the QCD and standard model Higgs boson contributions to these correlations. QCD induced transverse polarization of top quarks is found to be sizeable and measurable at a high-energy $e^+e^-$ collider with an integrated luminosity of 10 $({\rm fb})^{-1}$ which is converted into a photon collider by backscattering of laser photons.Comment: 8 pages. No fig. Preprint UM-P-94/25 and PITHA 94/1

A Mid-Infrared Imaging Survey of Proto-Planetary Nebula Candidates

We present the data from a mid-infrared imaging survey of 66 proto-planetary nebula candidates using two mid-IR cameras (MIRAC2 and Berkcam) at the NASA Infrared Telescope Facility and the United Kingdom Infrared Telescope. The goal of this survey is to determine the size, flux, and morphology of the mid-IR emission regions, which sample the inner regions of the circumstellar dust shells of proto-planetary nebulae. We imaged these proto-planetary nebulae with narrow-band filters ($\Delta\lambda / \lambda \sim 10$) at wavelengths of notable dust features. With our typical angular resolution of 1\arcsec, we resolve 17 sources, find 48 objects unresolved, and do not detect 1 source. For several sources, we checked optical and infrared associations and positions of the sources. In table format, we list the size and flux measurements for all the detected objects and show figures of all the resolved sources. Images for all the detected objects are available on line in FITS format from the Astronomy Digital Image Library at the National Center for Supercomputing Application. The proto-planetary nebula candidate sample includes, in addition to the predominant proto-planetary nebulae, extreme asymptotic giant branch stars, young planetary nebulae, a supergiant, and a luminous blue variable. We find that dust shells which are cooler ($\rm T \sim 150$ K) and brighter in the infrared are more easily resolved. Eleven of the seventeen resolved sources are extended and fall into one of two types of mid-IR morphological classes: core/elliptical or toroidal. Core/elliptical structures show unresolved cores with lower surface brightness elliptical nebulae. Toroidal structures show limb-brightened peaks suggesting equatorial density enhancements. We argue that core/ellipticals have denser dust shells than toroidals.Comment: 32 pages, 5 tables, 2 e/ps figures (fig3 is available through ADIL [see text]), to be published in ApJS May 1999 issu