Evidence flow graph methods for validation and verification of expert systems

The results of an investigation into the use of evidence flow graph techniques for performing validation and verification of expert systems are given. A translator to convert horn-clause rule bases into evidence flow graphs, a simulation program, and methods of analysis were developed. These tools were then applied to a simple rule base which contained errors. It was found that the method was capable of identifying a variety of problems, for example that the order of presentation of input data or small changes in critical parameters could affect the output from a set of rules

Hybrid InGaAsP-InP Mach-Zehnder racetrack resonator for thermooptic switching and coupling control

An InGaAsP-InP optical switch geometry based on electrical control of waveguide-resonator coupling is demonstrated. Thermooptic tuning of a Mach-Zehnder interferometer integrated with a racetrack resonator is shown to result in switching with ON-OFF contrast up to 18.5 dB. The optical characteristics of this unique design enable a substantial reduction of the switching power, to a value of 26 mW in comparison with 40 mW for a conventional Mach-Zehnder interferometer switch. Modulation response measurements reveal a 3 dB bandwidth of 400 kHz and a rise time of 1.8 µs, comparing favorably with current state-of-the-art thermooptic switches

[Fe II] and H2 filaments in the Supernova Remnant G11.2-0.3: Supernova Ejecta and Presupernova Circumstellar Wind

We present the results of near-infrared imaging and spectroscopic observations of the young, core-collapse supernova remnant (SNR) G11.2-0.3. In the [Fe II] 1.644 um image, we first discover long, clumpy [Fe II] filaments within the radio shell of the SNR, together with some faint, knotty features in the interior of the remnant. We have detected several [Fe II] lines and HI Br-G line toward the peak position of the bright southeastern [Fe II] filament. The derived extinction is large (Av=13 mag) and it is the brightest [Fe II] filament detected toward SNRs to date. By analyzing two [Fe II] 1.644 um images obtained in 2.2 yrs apart, we detect a proper motion corresponding to an expansion rate of 0.''035 (0.''013) /yr [or 830 (310) km/s]. We also discover two small H2 filaments. One is bright and along the SE boundary of the radio shell, while the other is faint and just outside of its NE boundary. We have detected H2 (2-1) S(3) line toward the former filament and derive an excitation temperature of 2,100 K. We suggest that the H2 filaments are dense clumps in a presupernova circumstellar wind swept up by the SNR shock while the [Fe II] filaments are probably composed of both shocked wind material and shocked supernova (SN) ejecta. The distribution of [Fe II] filaments may indicate that the SN explosion in G11.2-0.3 was asymmetric as in Cassiopeia A. Our results support the suggestion that G11.2-0.3 is a remnant of a SN IIL/b interacting with a dense red supergiant wind.Comment: 30 pages with 10 figures, To appear in the Astrophysical Journa

Semiclassical correlators of three states with large S^5 charges in string theory in AdS_5 x S^5

We consider semiclassical computation of 3-point correlation functions of (BPS or non-BPS) string states represented by vertex operators carrying large charges in S5. We argue that the AdS5 part of the construction of relevant semiclassical solution involves the two basic ingredients: (i) configuration of three glued geodesics in AdS2 suggested by Klose and McLoughlin in arXiv:1106.0495 and (ii) a particular Schwarz-Christoffel map of the 3-geodesic solution in cylindrical (tau, sigma) domain into the complex plane with three marked points. This map is constructed using the expression for the AdS2 string stress tensor which is uniquely determined by the 3 scaling dimensions as noted by Janik and Wereszczynski in arXiv:1109.6262 (our solution, however, is different from theirs). We also find the S5 part of the solution and thus the full expression for the semiclassical part of the 3-point correlator for several examples: extremal and non-extremal correlators of BPS states and a particular correlator of "small" circular spinning strings in S3 part of S5. We demonstrate that for the BPS correlators the results agree with the large charge limit of the corresponding supergravity and free gauge theory expressions.Comment: 43 pages, 4 figures; v2: minor corrections; v3: comments added at the end of section 3 and in section 5; v4: minor corrections; v5: discussion in subsection 3.3 correcte

Electromagnetic Properties for Arbitrary Spin Particles: Part 2 −- Natural Moments and Transverse Charge Densities

In a set of two papers, we propose to study an old-standing problem, namely the electromagnetic interaction for particles of arbitrary spin. Based on the assumption that light-cone helicity at tree level and $Q^2=0$ should be conserved non-trivially by the electromagnetic interaction, we are able to derive \emph{all} the natural electromagnetic moments for a pointlike particle of \emph{any} spin. In this second paper, we give explicit expressions for the light-cone helicity amplitudes in terms of covariant vertex functions, leading to the natural electromagnetic moments at $Q^2=0$. As an application of our results, we generalize the discussion of quark transverse charge densities to particles with arbitrary spin.Comment: 12 pages, 1 tabl

An Empirical Predictive Relationship for Assessing the Seismic Stability of Slopes

The objective of the study presented herein is to develop an empirical predictive relationship for permanent relative displacements for use in assessing the seismic stability of slopes, dams, and/or embankments subjected to active shallow crustal earthquake motions. A total of 330 horizontal motions, recorded at rock sites during 29 earthquakes in active shallow crustal regions (e.g., western North America: WNA), were used in this study. For each motion, the permanent relative displacements were computed using the Newmark sliding block procedure for a suite of yield-accelerations: 0.01, 0.05, 0.10, and 0.20 g. The predictive relationship proposed herein was derived by performing separate regression analyses for each yield-acceleration. This allows the relationship to be simply formulated in terms of ground motion characteristic parameters, independent of yield-acceleration (ky), and results in lower standard deviations than those for relations developed by regressing all the data in a single analysis. The non-linear mixed-effects technique was used to regress the relative displacement data as functions of maximum ground accelerations and velocities (Amax and Vmax, respectively). The median permanent relative displacements predicted for WNA rock motions decreases with increasing ky/Amax but increases with increasing Vmax. Also, the rate of decrease in displacement with respect to ky/Amax varies as a function of ky

Some Systematics of the Coupling Constant Dependence of N=4 Yang-Mills

The operator, O_\tau, that generates infinitesimal changes of the coupling constant in N=4 Yang-Mills sits in the same supermultiplet as the superconformal currents. We show how superconformal current Ward identities determine a class of terms in the operator product expansion of O_\tau with any other operator. In certain cases, this leads to constraints on the coupling dependence of correlation functions in N=4 Yang-Mills. As an application, we demonstrate the exact non-renormalization of two and certain three-point correlation functions of BPS operators.Comment: 56 pages, LaTeX; amended and expanded arguments, added reference

An Innovative Approach for Community Engagement: Using an Audience Response System

Community-based participatory research methods allow for community engagement in the effort to reduce cancer health disparities. Community engagement involves health professionals becoming a part of the community in order to build trust, learn from the community and empower them to reduce disparities through their own initiatives and ideas. Audience Response Systems (ARS) are an innovative and engaging way to involve the community and obtain data for research purposes using keypads to report results via power point. The use of ARS within communities is very limited and serves to widen the disparity gap by not delivering new advances in medical knowledge and technology among all population groups. ARS was implemented at a community town hall event sponsored by a National Institute on Minority Health and Health Disparities Exploratory Center of Excellence, the Center for Equal Health. Participants appreciated being able to see how everyone else answered and felt included in the research process. ARS is beneficial because the community can answer truthfully and provides instant research results. Additionally, researchers can collect large amounts of data quickly, in a non-threatening way while tracking individual responses anonymously. Audience Response Systems proved to be an effective tool for successfully accomplishing community-based participatory research

Gold(I)-Catalysed Direct Thioetherifications Using Allylic Alcohols: an Experimental and Computational Study

A gold(I)-catalysed direct thioetherification reaction between allylic alcohols and thiols is presented. The reaction is generally highly regioselective (S(N)2′). This dehydrative allylation procedure is very mild and atom economical, producing only water as the by-product and avoiding any unnecessary waste/steps associated with installing a leaving or activating group on the substrate. Computational studies are presented to gain insight into the mechanism of the reaction. Calculations indicate that the regioselectivity is under equilibrium control and is ultimately dictated by the thermodynamic stability of the products