cssi/SciSciGPT-SciSciNet huggingface dataset:
GRAIN BOUNDARY STRUCTURE IN NiO

Transmission electron microscopy is used to study the structure of grain boundaries (GBs) in NiO. tilt GBs in NiO are generally found to be faceted. Structural periodicities within facets have been observed at low and high misorientation. An effective reduced atomic density at the GB within a region of 0.5 to 0.8 nm in width is suggested by the defocus contrast behavior of high-angle tilt and twist GBs.
Synthesis of (6R,7S)-lactacystin and 6-deoxylactacystin from a common intermediate

Abstract The stereocontrolled syntheses of (6R,7S)-lactacystin and (6)-deoxylactacystin, analogs of the neurotrophic agent lactacystin, are described.
Field emission current-voltage curves as a diagnostic for scanning tunneling microscope tips

Abstract The current-voltage ( I–V ) characteristics of a low-temperature ultrahigh-vacuum scanning tunneling microscope (STM) tip positioned >100 A from a planar surface have been recorded. We find curvature in the Fowler-Nordheim plots (log 10 ( I/V 2 ) versus 1/ V ) due to the tip-plane geometry as has been predicted theoretically. In addition, oscillations and sharp breaks in these I–V curves are observed over a wide voltage range, 50–1000 V. These I–V curves are used to characterize the STM tips prior to tunneling.
Role and discipline relationships in a transdisciplinary biomedical team: structuration, values override, and context scaffolding

Though accepted that “team science is needed to tackle and conquer the health problems that are plaguing our society” (Disis and Slattery, 2010) significant empirical evidence of team mechanisms and functional dynamics is still lacking. Through grounded methods (Borner et al., 2010) the relationship between scientific disciplines and team roles was observed in a National Institutes of Health-funded (NIH) research consortium. Interviews and the Organizational Culture Assessment Instrument (OCAI) (Cameron and Quinn, 2006) were employed. Findings show strong role and discipline idiosyncrasies that when viewed separately provide different insights into team functioning and change receptivity. When considered simultaneously, value-latent characteristics emerged showing self-perceived contributions to the team. This micro/meso analysis suggests that individual participation in team level interactions can inform the structuration of roles and disciplines in an attempt to tackle macro level problems.
Coarse and fine bit synchronization for WDM interconnections using two subcarrier-multiplexed control pilot tones

We demonstrate the use of high- and low-frequency subcarrier-multiplexed pilot tones as control signals to achieve both coarse and fine synchronization in a bit-parallel wavelength-division-multiplexed optical interconnection. These control signals are located on each of the two outer wavelengths and are combined with the baseband data before transmission. The phase difference of the tones enables: (1) fine synchronization to <1/8 of a bit time in the optical domain for all wavelength channels simultaneously by comparing the high-frequency tones and using a discrete set of wavelength-dependent delays and (2) coarse synchronization over several bit times in the electrical domain by comparing the low-frequency tones and using shift registers.
Software Engineering with Reusable Designs and Code

For over six years Raytheon's Missile Systems Division, Information Processing Systems Organization has used a successful approach in developing and maintaining business software. The approach centers on the fact that 60 percent of all business application designs and code are redundant and can be standardized and reused. This approach has resulted in significant gains in productivity and reliability and improved end-user relations, while providing better utilization of data processing personnel, primarily in the maintenance phase of the software life cycle.
Warm HCN, C2H2, and CO in the disk of GV Tau

We present the first high-resolution, ground-based observations of HCN and C2H2 toward the T Tauri binary star system GV Tau. We detected strong absorption due to HCN ν3 and weak C2H2 [ν3 and ν2 + (ν4 + ν5)] absorption toward the primary (GV Tau S) but not the infrared companion. We also report CO column densities and rotational temperatures, and present abundances relative to CO of HCN/CO ~ 0.6% and C2H/CO ~ 1.2% and an upper limit for CH4/CO < 0.37% toward GV Tau S. Neither HCN nor C2H2 were detected toward the infrared companion, and results suggest that abundances may differ between the two sources.
Scaling Theory of Two-Dimensional Metal-Insulator Transitions

We discuss the recently discovered two-dimensional metal-insulator transition in zero magnetic field in the light of the scaling theory of localization. We demonstrate that the observed symmetry relating conductivity and resistivity follows directly from the quantum critical behavior associated with such a transition. In addition, we show that very general scaling considerations imply that any disordered two-dimensional metal is a perfect metal, but most likely not a Fermi liquid.
Multigrid calculation of internal flows in complex geometries

The development, validation, and application of a general purpose multigrid solution algorithm and computer program for the computation of elliptic flows in complex geometries is presented. This computer program combines several desirable features including a curvilinear coordinate system, collocated arrangement of the variables, and Full Multi-Grid/Full Approximation Scheme (FMG/FAS). Provisions are made for the inclusion of embedded obstacles and baffles inside the flow domain. The momentum and continuity equations are solved in a decoupled manner and a pressure corrective equation is used to update the pressures such that the fluxes at the cell faces satisfy local mass continuity. Despite the computational overhead required in the restriction and prolongation phases of the multigrid cycling, the superior convergence results in reduced overall CPU time. The numerical scheme and selected results of several validation flows are presented. Finally, the procedure is applied to study the flowfield in a side-inlet dump combustor and twin jet impingement from a simulated aircraft fuselage.
Application of Neutron Diffraction to Measure Residual Strains in Various Engineering Composite Materials

An experimental neutron diffraction technique was used to measure residual strains that developed in multiphase composite materials during postfabrication cooling. The reinforcement geometries that were studied include unidirectional fibers, randomly oriented single crystal whiskers, and equiaxed particles. Both metal and ceramic matrices and reinforcements were considered
A characterization of a family of rules for the adjudication of conflicting claims

Abstract We consider the problem of adjudicating conflicting claims, and characterize the family of rules satisfying four standard invariance requirements, homogeneity, two composition properties, and consistency. It takes as point of departure the characterization of the family of two-claimant rules satisfying the first three requirements, and describes the restrictions imposed by consistency on this family and the further implications of this requirement for problems with three or more claimants. The proof, which is an alternative to Moulinʼs original proof [Moulin, H., 2000. Priority rules and other asymmetric rationing methods. Econometrica 68, 643–684], is based on a general method of constructing consistent extensions of two-claimant rules [Thomson, W., 2007. On the existence of consistent rules to adjudicate conflicting claims: a constructive geometric approach. Rev. Econ. Design 11, 225–251], which exploits geometric properties of paths of awards, seen in their entirety.
Synthesis of methoxy and hydroxy analogues of 1,2,3,4,4a,9a-hexahydro-4a-fluorenamine : rigid phencyclidine analogues as probes of phencyclidine binding site topography

To further probe the topography of the PCP binding site, methods were developed for the synthesis of six oxygenated analogues of HFA that serve as probes of the putative hydrogen bonding interaction between the ligands and this binding site. This chemistry involves the Diels-Alder reaction of an appropriately substituted methyl indene-3-carboxylate with butadiene. Synthetic routes to all possible monomethoxylated derivatives of indene-3-carboxylate were thus devised and are detailed herein. An alternative method was developed to generate the homoenolate equivalent of 1-indanone, and a tert-butyl ester was demonstrated to act as a masked acid equivalent in the Friedel-Crafts acylation reaction
Coupled organic synthesis and mineral alteration on meteorite parent bodies

The hypothesis that the soluble fraction of the organic compounds present in carbonaceous chondrite meteorites was formed during aqueous alteration of the parent body was tested with masstransfer, reaction-path calculations. In these calculations, we start with likely compositions of the original parent body and asteroidal fluids that are far from thermodynamic equilibrium, and metastable and stable equilibrium constraints are imposed as the total Gibbs free energy of the parent body environment is minimized. The results of these calculations suggest that the classes of soluble organic compounds present in carbonaceous chondrite meteorites could have formed during relatively low temperature aqueous alteration of the meteorite parent body or bodies. The main controls on the potential for synthesis and transformation of organic compounds were the oxidation state of the rock/fluid system, the bulk composition of that system, and the temperatures that were achieved during the alteration event or events. It also appears that the alteration mineral assemblages were influenced by the presence of soluble organic compounds and reaction among them.
Causal structures of pp-waves

We discuss the causal structure of pp-wave spacetimes using the ideal point construction outlined by Geroch, Kronheimer, and Penrose. This generalizes the recent work of Marolf and Ross, who considered similar issues for plane wave spacetimes. We address the question regarding the dimension of the causal boundary for certain specific pp-wave backgrounds. In particular, we demonstrate that the pp-wave spacetime which gives rise to the = 2 sine-Gordon string world-sheet theory is geodesically complete and has a one-dimensional causal boundary.
Stochastic Bounds on Distributions of Optimal Value Functions with Applications to PERT, Network Flows and Reliability

In many classical combinatorial optimization problems, including critical and shortest paths, maximum flow, and network reliability, the introduction of uncertainty considerably complicates the calculation of system performance. In fact, in these contexts, computing system performance exactly can often be an impossible task. Therefore, obtaining stochastic bounds on the system's performance becomes an attractive and useful alternative. This paper studies several stochastic bounds that are applicable to these contexts and to a broader set of problems that can be described by the general combinatorial concepts of clutters and blocking clutters. We begin our discussion by defining these unifying concepts and illustrating their specialization in several problem contexts.
Phonon limited transport in graphene pseudospintronic devices

Graphene pseudospin (G-PsS) devices have the potential to far outperform traditional CMOS devices. This is due to a predicted room temperature phase transition from Fermi liquid to Bose-Einstein condensate in double layer graphene [1]. The condensate is formed when electrons and holes in residing in opposite graphene layers bind into excitons as a result of strong interlayer Coulomb interactions. This device is expected to exhibit interlayer superfluidity, which allows for large interlayer currents at correspondingly low interlayer bias voltages. As G-PsS device are expected to operate at room temperature, it is important to understand how the electron-phonon interaction (EPI) affects device performance.
Political economy of R&D to support the modern competitiveness of nations and determinants of economic optimization and inertia

Abstract The study here analyzes the association between R&D expenditure (as % of GDP) and labor productivity across leading geo-economic players. Empirical evidence seems to show, during the period of analysis, a strong positive association between public and private R&D expenditure. In addition, when R&D spending of business enterprise sector exceeds R&D spending of government sector, the labor productivity tends to growth (economic optimization), ceteris paribus. In general, effects of friction (inertia) on labor productivity growth are displayed by countries whose R&D intensity is driven mainly by R&D expenditure of government sector. Results provide fruitful implications that can support a rational political economy of R&D in order to foster the competitiveness of countries in fast-changing and turbulent markets.
ASYMPTOTICALLY CONFORMAL FIXED POINTS AND HOLOMORPHIC MOTIONS

The term integrable asymptotically conformal at a point for a quasiconformal map defined on a domain is defined. Furthermore, we prove that there is a normal form for this kind attracting or repelling or super-attracting fixed point with the control condition under a quasicon- formal change of coordinate which is also asymptotically conformal at this fixed point. The change of coordinate is essentially unique. These results generalize Konig's Theorem and Bottcher's The- orem in classical complex analysis. The idea in proofs is new and uses holomorphic motion theory and provides a new understanding of the inside mechanism of these two famous theorems too.
On convergence rate of scalar Hegselmann-Krause dynamics

In this work, we derive a new upper bound on the termination time of the Hegselmann-Krause model for opinion dynamics. Using a novel method, we show that the process terminates in no more than O(n3) iterations, which improves the best known upper bound of O(n4) by a factor of n.
Impulse distributions in dense granular flows: Signatures of large-scale spatial structures

We study the impulse distribution in a model of gravity-driven granular flow and show that changes in the distribution are correlated with the appearance of clusters of "frequently-colliding" particles. Our simulations show increasingly large linear clusters as the flow velocity decreases. The dissipative nature of the collisions leads to an increase of small-impulse events as the size of these clusters grow and can explain the observed changes in the impulse distribution as the flow rate decreases.
Conjugacies for Tiling Dynamical Systems

We consider tiling dynamical systems and topological conjugacies between them. We prove that the criterion of being of finite type is invariant under topological conjugacy. For substitution tiling systems under rather general conditions, including the Penrose and pinwheel systems, we show that substitutions are invertible and that conjugacies are generalized sliding block codes.
Fuel Saving and Control for Hybrid Electric Powertrains

This paper focuses on comparing the performance of the embedded control of a hybrid powertrain with the original and downsized engine. The main idea is to store the normally wasted mechanical regenerative energy in energy storage devices for later usage. The regenerative energy recovery opportunity exists in any condition where the speed of motion is in the opposite direction to the applied force or torque. A rule based optimal robust control algorithm is developed and is tuned for different work cycles. A comparison of the fuel savings using the hybrid system with the original and downsized engines is performed.
A Turbulent Origin for Flocculent Spiral Structure in Galaxies

The flocculent structure of star formation in galaxies has a Fourier transform power spectrum for azimuthal intensity scans with a power-law slope that increases systematically from about -1 at large scales to about -5/3 at small scales. This is the same pattern as in the power spectra for azimuthal scans of H I emission in the Large Magellanic Clouds and for flocculent dust clouds in galactic nuclei. The steep part also corresponds to the slope of about -3 for two-dimensional power spectra that have been observed in atomic and molecular gas surveys of the Milky Way and the Large and Small Magellanic Clouds. The power-law structure for star formation in galaxies arises in both flocculent and grand-design disks, which implies that star formation is the same in each and most likely related to turbulence. The characteristic scale that separates these two slopes corresponds to several tens of pixels or several hundred parsecs in most galaxies, which is comparable to the scale height, the inverse of the Jeans wavenumber, and the size of the largest star complexes. We suggest that the power spectrum of optical light is the result of turbulence and that the large-scale turbulent motions are generated by sheared gravitational instabilities that make flocculent spiral arms first and then cascade to form clouds and clusters on smaller scales. Stellar energy sources presumably contribute to this turbulence by driving smaller scale motions and by replacing the gravitational binding energy that is released during spiral arm collapse. The spiral wave mode in the image of M81 is removed by reconstructing the Fourier transforms without the lowest 10 wavenumbers. The result shows the underlying flocculent spirals and reverse-shear spirals of star formation that are normally overwhelmed by the density wave.
Application of a new method in adaptive control

The adaptive control function technique is applied to design a remarkably simple adaptive lateral stability augmentation system for a hypothetical manned, lifting-body entry vehicle. This system is proven stable under certain ideal conditions. The general principles of the adaptive control function technique are summarized and used to motivate the steps in the design for this specific multicontrol-point application. The basic operating principle is that sums of properly modulated conventional linear feedforward and feedback signals provide the control functions needed to obtain specified responses in a number of output variables of a linear controlled element. System performance is demonstrated via computer simulation. Data show the adaptive system highly capable of coping with the unstable nature of the vehicle as well as those nonideal effects (time-varying vehicle-vehicle model mismatch, disturbance inputs, outer control loops, and noise suppression filtering) not considered in the analytical design. A comparison of the gains set by the adaptive system, with those selected by a competent aircraft flight control system analyst as optimum, confirms in still another way the reasonable performance of this system.
Intensified array camera imaging of solid surface combustion aboard the NASA Learjet

An intensified array camera has been used to image weakly luminous flames spreading over thermally thin paper samples in a low-gravity environment aboard the NASA-Lewis Learjet. The aircraft offers 10 to 20 sec of reduced gravity during execution of a Keplerian trajectory and allows the use of instrumentation that is delicate or requires higher electrical power than is available in drop towers. The intensified array camera is a charge intensified device type that responds to light between 400 and 900 nm and has a minimum sensitivity of 10(exp 6) footcandles. The paper sample, either ashless filter paper or a lab wiper, burns inside a sealed chamber which is filled with 21, 18, or 15 pct. oxygen in nitrogen at one atmosphere. The camera views the edge of the paper and its output is recorded on videotape. Flame positions are measured every 0.1 sec to calculate flame spread rates. Comparisons with drop tower data indicate that the flame shapes and spread rates are affected by the residual g level in the aircraft.
Scanning tunneling microscopy studies of size and morphology of Pt/graphite catalysts

The sizes and surface morphologies of reduced Pt crystallites supported on three different graphitic substrates are examined with scanning tunneling microscopy (STM). The roughness of the substrates decreases the size of the catalyst crystallites without noticeable changes in morphology. Functionalization of the substrate with HNO3 results in considerable changes in both size and shape distribution of the supported catalysts. Crystallites supported on unfunctionalized graphites are rectangular parallelepiped with rounded corners, while those supported on functionalized NGHPG are more irregular in shape and more heterogeneous.
17O NMR spectroscopy of substituted methyleneindanones: relationship between chemical shift and oxygen atom electron density

Abstract 17O NMR spectroscopic data for eigth β-substituted methyleneindanones obtained at natural abundance in acetonitrile at 75°C are reported. 17O NMR data for ten para-substituted E-benzalindanones, enriched with 17O, were recorded in acetonitrile at 75°C. The 17O NMR data for the E-benzalindanones gave good correlations with sigma plus values, with literature carbonyl IR stretching frequencies, and with literature 17O NMR carbonyl data of chalcones and 5-aryl-2,3-furandiones. The carbonyl oxygen atom electron density (AM1) gave good correlation with the carbonyl 17O NMR chemical shift of both β-substituted methyleneindanones and the E-benzalindanones.
Finding regular insertion encodings for permutation classes

We describe a practical algorithm which computes the accepting automaton for the insertion encoding of a permutation class, whenever this insertion encoding forms a regular language. This algorithm is implemented in the accompanying Maple package InsEnc, which can automatically compute the rational generating functions for such classes.
Nonlinear image filtering within IDP

IDP++, image and data processing in C++, is a set of signal processing libraries written in C++. It is a multi-dimension (up to four dimensions), multi-data type (implemented through templates) signal processing extension to C++. IDP++ takes advantage of the object-oriented compiler technology to provide `information hiding.' Users need only know C, not C++. Signals or data sets are treated like any other variable with a defined set of operators and functions. We present here some examples of the nonlinear filter library within IDP++. Specifically, the results of min, max, median, (alpha) -trimmed mean, and edge-trimmed mean filters as applied to a real aperture radar (RAR) and synthetic aperture radar (SAR) data set.
Optical phase conjugation with smooth pump profiles.

Abstract : We present analytical results for the steady-state signal and phase-conjugate fields interacting with smoothly varying nondepleted pump waves in a nearly degenerate four-wave-mixing geometry. Signal depletion is retained in the equations and we study the effect that detuning on the input signal from the degenerate pump amplitudes has on the reflected conjugate wave and the transmitted signal wave. A general result is derived for the appearance of spontaneous amplification under weak restrictions on the profile of the degenerate pump fields. The conjugation of the phase front of the signal is studied for exponential and hyperbolic secant functions multiplying the coupling coefficients and comparison is made with corresponding results for square profile pump fields. These results are discussed and their relevance to phase conjugation of pulses is examined. Keywords: Degenerate four wave mixing, Optical phase conjugation, Signal field, Smooth profiles, and Pump profiles.
K-orbits on the flag variety and strongly regular nilpotent matrices

In two 2006 papers, Kostant and Wallach constructed a complexified Gelfand–Zeitlin integrable system for the Lie algebra $${\mathfrak{gl}(n + 1,\mathbb{C})}$$ and introduced the strongly regular elements, which are the points where the Gelfand–Zeitlin flow is Lagrangian. Later Colarusso studied the nilfiber, which consists of strongly regular elements such that each i × i submatrix in the upper left corner is nilpotent. In this paper, we prove that every Borel subalgebra contains strongly regular elements and determine the Borel subalgebras containing elements of the nilfiber by using the theory of $${K_{i} = GL(i - 1,\mathbb{C}) \times GL(1,\mathbb{C})}$$ -orbits on the flag variety for $${\mathfrak{gl}(i,\mathbb{C})}$$ for 2 ≤ i ≤ n + 1. As a consequence, we obtain a more precise description of the nilfiber. The K i -orbits contributing to the nilfiber are closely related to holomorphic and anti-holomorphic discrete series for the real Lie groups U(i, 1), with i ≤ n.
Synthesis and hydrolysis of fluoropyridinyl containing chlorosilanes

Abstract 2-Fluoro-3-dimethylchlorosilylpyridine (A) and 3-fluoro-4-dimethylchlorosilylpyridine (B) were synthesized from the corresponding fluoro-lithio-pyridines and dimethyldichlorosilane at −76°C. The liquid products were unstable on standing. A and B were hydrolyzed in aqueous ammonia at room temperature to give disiloxanes which are stable crystalline solids. The new compounds were characterized by IR, 1H NMR and MS.
Semantic Web Technologies to Reconcile Privacy and Context Awareness

Increasingly, application developers are looking for ways to provide users with higher levels of personalization that capture different elements of a user's operating context, such as her location, the task that she is currently engaged in, who her colleagues are, etc. While there are many sources of contextual information, they tend to vary from one user to another and also over time. Different users may rely on different location tracking functionality provided by different cell phone operators; they may use different calendar systems, etc. In this article, we describe work on a Semantic e-Wallet aimed at supporting automated identification and access of personal resources, each represented as a Semantic Web Service. A key objective is to provide a Semantic Web environment for open access to a user's contextual resources, thereby reducing the costs associated with the development and maintenance of context-aware applications. A second objective is, through Semantic Web technologies, to empower users to selectively control who has access to their contextual information and under which conditions. This work has been carried out in the context of my-Campus, a context-aware environment aimed at enhancing everyday campus life. Empirical results obtained on Carnegie Mellon's campus are discussed.
(+)-saxitoxin : A first and second generation stereoselective synthesis

A stereoselective synthesis of the bis-guanidinium toxin (+)-saxitoxin (STX), the agent infamously associated with red tides and paralytic shellfish poisoning, is described. Our approach to this unique natural product advances through an unusual nine-membered ring guanidine intermediate 39 en route to the tricyclic skeleton that defines STX. The effectiveness of this strategy is notable, as only four steps are needed to transform 39 into the target molecule, including a four-electron alkene oxidation catalyzed by OsCl3. Construction of the critical monocyclic guanidine has been achieved through two channels, the first of which makes use of Rh-catalyzed C−H amination and highlights a novel class of heterocyclic N,O-acetals as iminium ion equivalents for crafting functionalized amines. A second route to 39 relies on a stereoselective acetylide dianion addition to a serine-based nitrone, thereby facilitating the preparation of STX in just 14 linear steps from commercial material.
Solid phase synthesis of mixture-based acyclic and heterocyclic small molecule combinatorial libraries from resin-bound polyamides

The development of soluble mixture-based heterocyclic combinatorial libraries derived from amino acids and peptides is described. Starting with a "toolbox" of various chemical transformations, including alkylations, reductions, acylations, and the use of a variety of bifunctional reagents, the "libraries from libraries" concept has been expanded to encompass the development of more than fifty positional scanning combinatorial libraries each composed of tens of thousands of low molecular weight acyclic and heterocyclic compounds.
Modified Shielding Jet Model for Twin-Jet Shielding Analysis

An analytical model to estimate the shielding of noise emitted from a point noise source has been developed assuming the shielding jet to be a cylinder of constant radius with uniform flow across the cross section. Comparison to experiment indicated that the model overestimates diffraction of sound around the jet in the far downstream region. The shielding jet model is modified to include widening downstream of the nozzle exit. This not only represents a more realistic model of the jet, but is also expected to improve the shielding estimate downstream. The modified jet model incorporates a Mach number dependent widening rate, a corresponding decrease in flow velocity downstream and an equivalent slug flow evaluation to retain the locally parallel flow approximation of the model development. The shielding analysis with modified jet model is compared to measured data for a subsonic isothermal air jet and a simulated hot subsonic jet. Improvement of the shielding estimate is discussed.
Distributed Kalman Filtering Over Massive Data Sets: Analysis Through Large Deviations of Random Riccati Equations

This paper studies the convergence of the estimation error process and the characterization of the corresponding invariant measure in distributed Kalman filtering for potentially unstable and large linear dynamic systems. A gossip network protocol termed modified gossip interactive Kalman filtering (M-GIKF) is proposed, where sensors exchange their filtered states (estimates and error covariances) and propagate their observations via intersensor communications of rate γ; γ is defined as the averaged number of intersensor message passages per signal evolution epoch. The filtered states are interpreted as stochastic particles swapped through local interaction. This paper shows that the conditional estimation error covariance sequence at each sensor under M-GIKF evolves as a random Riccati equation (RRE) with Markov modulated switching. By formulating the RRE as a random dynamical system, it is shown that the network achieves weak consensus, i.e., the conditional estimation error covariance at a randomly selected sensor converges weakly (in distribution) to a unique invariant measure. Further, it is proved that as γ → ∞ this invariant measure satisfies the large deviation (LD) upper and lower bounds, implying that this measure converges exponentially fast (in probability) to the Dirac measure δ P* , where P* is the stable error covariance of the centralized (Kalman) filtering setup. The LD results answer a fundamental question on how to quantify the rate at which the distributed scheme approaches the centralized performance as the intersensor communication rate increases.
Sensor Bias Estimation in the Presence of Data Association Uncertainty

This paper considers the problem of dynamic residual bias estimation in the presence of measurement association uncertainty using common targets of opportunity under a decentralized information processing architecture i.e. independent trackers at each sensor. This is done by extending the scope of the synchronous version of the bias estimation algorithm presented by Lin, Bar-Shalom and Kirubarajan in "Multisensor-Multitarget Bias Estimation for General Asynchronous Sensors" to develop approaches to bias estimation in the presence of measurement association uncertainty. We consider the computational complexity and the sensor-to-fusion-center communication requirements of each of these approaches and compare their simulated performance in terms of RMSE and consistency. Though the simulations are performed with synchronous polar measurements having additive biases, the algorithm may easily be extended to the case with asynchronous measurements in other coordinate systems having both additive and multiplicative biases.
Target-atom inner-shell vacancy distributions created in collisions with heavy ion projectiles

Abstract A model of the evolution of Cu atom inner-shell electron configurations was developed in order to establish the relationship between the original populations created in K-vacancy producing collisions with fast heavy-ion projectiles and those that exist at the time of Cu Kα and Kβ X-ray emission. The model takes into account multi-step vacancy rearrangement processes that may occur prior to K X-ray emission. An iterative procedure is employed in which a set of trial parameters that define the original inner-shell population distributions are varied to obtain satisfactory agreement of the calculated Kα satellite relative intensities and energies, as well as the overall intensity ratio of Kβ satellites to Kα satellites, with the experimental data. In addition to deducing the properties of the original L- and M-shell population distribution, this procedure also provides the average value of the fluorescence yield for conversion between X-ray and K-vacancy production cross sections.
Optimal shape of a blob

This paper presents the solution to the following optimization problem: What is the shape of the two-dimensional region that minimizes the average Lp distance between all pairs of points if the area of this region is held fixed? Variational techniques are used to show that the boundary curve of the optimal region satisfies a nonlinear integral equation. The special case p=2 is elementary and for this case the integral equation reduces to a differential equation whose solution is a circle. Two nontrivial special cases, p=1 and p=∞, have already been examined in the literature. For these two cases the integral equation reduces to nonlinear second-order differential equations, one of which contains a quadratic nonlinearity and the other a cubic nonlinearity.
Toughening Behavior Involving Multiple Mechanisms: Whisker Reinforcement and Zirconia Toughening

Since the contribution of transformation toughening increases with the loca crack resistance (which is proportional to the toughness of the matrix), ZrO2 particles were added to a toughened, whisker-reinforced ceramic matrix. Analysis revealed that the combination of these multiple toughening agents should result in ceramic composites tougher than (1) that achieved by either mechanism by itself or (2) the sum of the two processes. The toughness of mullite could be increased 1.8-and 2.4-fold with a 20 vol% addition of ZrO2 particles or SiC whiskers, respectively. However, when 20 vol% of both ZrO2 particles and SiC whiskers were added, the toughness was increased at least 3-fold with monoclinic m-ZrO2 and by >5-fold with tetragonal t-ZrO2. The differences in the toughening achieved when t-ZrO2 vs m-ZrO2 is present in the SiC-whisker-reinforced mullite are attributed to differences in their interdependencies upon the whisker reinforcement.
Protracted screening in the periodic Anderson model

The asymmetric infinite-dimensional periodic Anderson model is examined with a quantum Monte Carlo simulation. For small conduction band filling, we find a severe reduction in the Kondo scale, compared to the impurity value, as well as protracted spin screening consistent with some recent controversial photoemission experiments. The Kondo screening drives a ferromagnetic transition when the conduction band is quarter filled and both the Ruderman-Kittel-Kasuya-Yosida (RKKY) and superexchange favor antiferromagnetism. We also find RKKY-driven ferromagnetic and antiferromagnetic transitions.
Adam Smith and the Ambiguity of Nations

What is the status of the nation state in Adam Smith's much celebrated intellectual system, the “Science of the Legislator”? This paper argues that it was historically transitory. Two aspects of Smith's treatment of states and international relations are examined. The first aspect concerns Smith's conception of the gains from international trade and openness. The second concerns his understanding of the dynamics of international conflict. These two aspects of Smith's conception of international relations go some way towards revealing the bases of his (skeptical) advocacy of a dramatic transformation of the British polity. Indeed, while the jurisprudential component of Smith's projected science of the legislator was never completed, surviving early lecture notes suggest that he regarded the nation-state as a transitional form: one that had already begun to need replacement in his day.
Computational Geometry Column 31

Several topics related to packing on a sphere are discussed: packing points, packing lines through the center, and packing k-flats in dimension d.
High-speed digital Golay code flaw detection system

Abstract A new, entirely digital, correlation flaw detection system is described which maintains optimal correlation detection over a much wider range of input signal-to-noise ratio conditions and operating speeds than previous single transducer correlation flaw detection systems. This new system uses special pseudo-random codes called complementary Golay codes to overcome the problem of self-noise which results from incomplete pulse-compression in the correlation process. Results are presented which show that the Golay code system produces better performance in the presence of grains and large reflecting surfaces, while offering much higher operating speed than previous single transducer correlation flaw detection systems.
Experimental and Numerical Investigations of a Split-Ring Test for Springback

This paper presents an in-depth experimental and numerical investigation of a split-ring test, which provides a simple yet effective benchmark for correlating forming and springback predictive capabilities with experimental measurements. The experimental procedure consists of deep drawing a circular 6111-T4 aluminum alloy into a cylindrical cup of 55mm depth, crosscutting nine rings each of 5mm wide from the cup, splitting the rings, and measuring their opening displacement, i.e., the springback amount. Experimental data obtained included punch force trajectories, drawn cup profile, thickness distribution after forming, and the ring openings after splitting. A numerical model is built to analyze the process, and both transversely isotropic and fully orthotropic yield criteria are investigated. Simulation results are validated against experimental data. A detailed numerical analysis is also conducted for stress distributions in each ring after each step and their relationship to the total springback amount. Stress and strain signatures suggested that the test is well suited for validating material models, such as anisotropic yield surface models and hardening models.
THE EFFECT OF THE TRANSIT OF VENUS ON ACRIM'S TOTAL SOLAR IRRADIANCE MEASUREMENTS: IMPLICATIONS FOR TRANSIT STUDIES OF EXTRASOLAR PLANETS

We have used the 2004 June 8 transit of Venus (ToV) as a surrogate to test observing methods, strategies, and techniques that are being contemplated for future space missions to detect and characterize extrasolar terrestrial planets (ETPs) as they transit their host stars, notably NASA's Kepler mission, planned for 2008. As an analog to "Kepler-like" photometric transit observations, we obtained (spatially unresolved) radiometric observations with the ACRIM 3 instrument on ACRIMSAT at a sampling cadence of 131 s to follow the effect of the ToV on the total solar irradiance (TSI). Contemporaneous high-resolution broadband imagery with NASA's TRACE spacecraft provided, directly, measures of the stellar (solar) astrophysical noise that can intrinsically limit such transit observations. During the Venus transit, which lasted ~5.5 hr, the planet's angular diameter was approximately 1/32 the solar diameter, thus covering ~0.1% of the stellar surface. With our ACRIM 3 data, we measure temporal changes in TSI with a 1 σ per sample (unbinned) uncertainty of approximately 100 mW m-2 (0.007%). A diminution in TSI of ~1.4 W m-2 (~0.1%, closely corresponding to the geometrically occulted area of the photosphere) was measured at mid-transit compared with a mean pre-/post-transit TSI of ~1365.9 W m-2. The radiometric light curve is complex because of the parallactic motion of Venus induced by ACRIMSAT's near-polar orbit, but exhibits the characteristic signature of photospheric limb darkening. These observations serve as a surrogate for future photometric observations of ETPs, such as Kepler will deliver. Detailed analysis of the ToV, a rare event within our own solar system, with time-resolved radiometry augmented with high-resolution imagery, provides a useful analog for investigating the detectability and characterization of ETPs from observations that are anticipated in the near future.
Mechanism design via correlation gap

For revenue and welfare maximization in single-dimensional Bayesian settings, Chawla et al. (STOC10) recently showed that sequential posted-price mechanisms (SPMs), though simple in form, can perform surprisingly well compared to the optimal mechanisms. In this paper, we give a theoretical explanation of this fact, based on a connection to the notion of correlation gap.Loosely speaking, for auction environments with matroid constraints, we can relate the performance of a mechanism to the expectation of a monotone submodular function over a random set. This random set corresponds to the winner set for the optimal mechanism, which is highly correlated, and corresponds to certain demand set for SPMs, which is independent. The notion of correlation gap of Agrawal et al. (SODA10) quantifies how much we "lose" in the expectation of the function by ignoring correlation in the random set, and hence bounds our loss in using certain SPM instead of the optimal mechanism. Furthermore, the correlation gap of a monotone and submodular function is known to be small, and it follows that certain SPM can approximate the optimal mechanism by a good constant factor.Exploiting this connection, we give tight analysis of a greedy-based SPM of Chawla et al. for several environments. In particular, we show that it gives an e/(e − 1)-approximation for matroid environments, gives asymptotically a 1/(1--1/√2πk)-approximation for the important sub-case of k-unit auctions, and gives a (p + 1)-approximation for environments with p-independent set system constraints.
The Lyth Bound and the end of inflation

We derive an extended version of the well-known Lyth Bound on the total variation of the inflaton field, incorporating higher-order corrections in slow roll. We connect the field variation Δ to both the spectral index of scalar perturbations and the amplitude of tensor modes. We then investigate the implications of this bound for 'small field' potentials, where the field rolls off a local maximum of the potential. The total field variation during inflation is generically of order mPl, even for potentials with a suppressed tensor/scalar ratio. Much of the total field excursion arises in the last e-fold of inflation and in single field models this problem can only be avoided via fine-tuning or the imposition of a symmetry. Finally, we discuss the implications of this result for inflationary model building in string theory and supergravity.
Recent Developments in the Sparse Fourier Transform: A compressed Fourier transform for big data

The discrete Fourier transform (DFT) is a fundamental component of numerous computational techniques in signal processing and scientific computing. The most popular means of computing the DFT is the fast Fourier transform (FFT). However, with the emergence of big data problems, in which the size of the processed data sets can easily exceed terabytes, the "fast" in FFT is often no longer fast enough. In addition, in many big data applications it is hard to acquire a sufficient amount of data to compute the desired Fourier transform in the first place. The sparse Fourier transform (SFT) addresses the big data setting by computing a compressed Fourier transform using only a subset of the input data, in time smaller than the data set size. The goal of this article is to survey these recent developments, explain the basic techniques with examples and applications in big data, demonstrate tradeoffs in empirical performance of the algorithms, and discuss the connection between the SFT and other techniques for massive data analysis such as streaming algorithms and compressive sensing.
A robust model for finding optimal evolutionary trees

Constructing evolutionary trees for species sets is a fundamental problem in computational biology. One of the standard models assumes the ability to compute distances between every pair of species, and seeks to find an edge-weighted treeT in which the distanced in the tree between the leaves ofT corresponding to the speciesi andj exactly equals the observed distance,d ij . When such a tree exists, this is expressed in the biological literature by saying that the distance function or matrix isadditive, and trees can be constructed from additive distance matrices in0(n 2) time. Real distance data is hardly ever additive, and we therefore need ways of modeling the problem of finding the best-fit tree as an optimization problem. In this paper we present several natural and realistic ways of modeling the inaccuracies in the distance data. In one model we assume that we have upper and lower bounds for the distances between pairs of species and try to find an additive distance matrix between these bounds. In a second model we are given a partial matrix and asked to find if we can fill in the unspecified entries in order to make the entire matrix additive. For both of these models we also consider a more restrictive problem of finding a matrix that fits a tree which is not only additive but alsoultrametric. Ultrametric matrices correspond to trees which can be rooted so that the distance from the root to any leaf is the same. Ultrametric matrices are desirable in biology since the edge weights then indicate evolutionary time. We give polynomial-time algorithms for some of the problems while showing others to be NP-complete. We also consider various ways of “fitting” a given distance matrix (or a pair of upper- and lower-bound matrices) to a tree in order to minimize various criteria of error in the fit. For most criteria this optimization problem turns out to be NP-hard, while we do get polynomial-time algorithms for some.
The black hole singularity in AdS/CFT

We explore physics behind the horizon in eternal AdS Schwarzschild black holes. In dimension d > 3 , where the curvature grows large near the singularity, we find distinct but subtle signals of this singularity in the boundary CFT correlators. Building on previous work, we study correlation functions of operators on the two disjoint asymptotic boundaries of the spacetime by investigating the spacelike geodesics that join the boundaries. These dominate the correlators for large mass bulk fields. We show that the Penrose diagram for d > 3 is not square. As a result, the real geodesic connecting the two boundary points becomes almost null and bounces off the singularity at a finite boundary time tc≠0. If this geodesic were to dominate the correlator there would be a ``light cone" singularity at tc. However, general properties of the boundary theory rule this out. In fact, we argue that the correlator is actually dominated by a complexified geodesic, whose properties yield the large mass quasinormal mode frequencies previously found for this black hole. We find a branch cut in the correlator at small time (in the limit of large mass), arising from coincidence of three geodesics. The tc singularity, a signal of the black hole singularity, occurs on a secondary sheet of the analytically continued correlator. Its properties are computationally accessible. The tc singularity persists to all orders in the 1/m expansion, for finite α', and to all orders in gs. Certain leading nonperturbative effects can also be studied. The behavior of these boundary theory quantities near tc gives, in principle, significant information about stringy and quantum behavior in the vicinity of the black hole singularity.