cssi/SciSciGPT-SciSciNet huggingface dataset:
Succinct strictly convex greedy drawing of 3-connected plane graphs

Geometric routing by using virtual locations is an elegant way for solving network routing problems. Greedy routing, where a message is simply forwarded to a neighbor that is closer to the destination, is a simple form of geometric routing. A greedy drawing of a graph G is a drawing of G for which the greedy routing works. Papadimitriou and Ratajczak conjectured that every 3-connected plane graph has a greedy drawing on the R2 plane (Papadimitriou and Ratajczak, 2005 [9]). Leighton and Moitra settled this conjecture positively in Leighton and Moitra (2010) [8]. A similar result was obtained by Angelini et al. (2010) [2]. However, their drawings have two major drawbacks: (1) their drawings are not necessarily planar; and (2) Ω(nlogn) bits are needed to represent each coordinate of their drawings, which is too large for routing algorithms for certain networks. Recently, He and Zhang [7] showed that every triangulated plane graph has a succinct (using O(logn) bit coordinates) greedy drawing on the R2 plane with respect to a metric function based on Schnyder realizers. However, their method does not work for 3-connected plane graphs. In this paper, we show that every 3-connected plane graph has a drawing on the R2 plane that is succinct, planar, strictly convex, and is greedy with respect to a metric function based on parameters derived from Schnyder woods.
Duality and chiral restoration from low-mass dileptons at the CERN-SpS

Abstract We review recent theoretical progress in low-mass dilepton production at CERN-SpS energies. Various hadronic approaches to calculate the vector correlator in hot/dense hadronic matter are discussed and confronted with each other. Possible consequences for the nature of chiral restoration are indicated.
On VC-minimal fields and dp-smallness

In this paper, we show that VC-minimal ordered fields are real closed. We introduce a notion, strictly between convexly orderable and dp-minimal, that we call dp-small, and show that this is enough to characterize many algebraic theories. For example, dp-small ordered groups are abelian divisible and dp-small ordered fields are real closed.
Toroidalization of generating sequences in dimension two function fields of positive characteristic

Abstract We give a characteristic free proof of the main result of [L. Ghezzi, H.T. Ha, O. Kashcheyeva, Toroidalization of generating sequences in dimension two function fields, J. Algebra 301 (2) (2006) 838–866. ArXiv:math.AC/0509697 .] concerning toroidalization of generating sequences of valuations in dimension two function fields. We show that when an extension of two-dimensional algebraic regular local rings R ⊂ S satisfies the conclusions of the Strong Monomialization theorem of Cutkosky and Piltant, the map between generating sequences in R and S has a toroidal structure.
Unitary equivalence to a complex symmetric matrix: Low dimensions

Abstract A matrix T ∈ M n ( C ) is UECSM if it is unitarily equivalent to a complex symmetric (i.e., self-transpose) matrix. We develop several techniques for studying this property in dimensions three and four. Among other things, we completely characterize 4 × 4 nilpotent matrices which are UECSM and we settle an open problem which has lingered in the 3 × 3 case. We conclude with a discussion concerning a crucial difference which makes dimension three so different from dimensions four and above.
Two-color QCD in 3D at finite baryon density

Abstract We study the low energy phase structure of SU(2) gauge theories in three-dimensional spacetime, at finite baryon density. The pseudoreality of representations of SU(2) permits an analytic study of a real baryon chemical potential, and the restriction to 3D results in a different global symmetry breaking pattern from the corresponding 4D model studied previously by Kogut et al. We find a second-order phase transition separating the normal phase and the baryon superconducting phase. The chemical potential dependence of condensates and baryon density are computed. We find that the phase structure and the excitation spectrum are essentially the same as in 4D, despite the different symmetry groups, indicating a universality that is rooted in the properties of Riemannian symmetric spaces.
ON THE ANOMALOUS BALMER LINE STRENGTHS IN GLOBULAR CLUSTERS

Spectral feature index diagrams with integrated globular clusters and simple stellar population models often show that some clusters have weak Hβ, so weak that even the oldest models cannot match the observed feature depths. In this work, we rule out the possibility that abundance mixture effects are responsible for the weak indices unless such changes operate to cool the entire isochrone. We discuss this result in the context of other explanations, including horizontal branch morphology, blue straggler populations, and nebular or stellar emission fill-in, finding a preference for flaring in M giants as an explanation for the Hβ anomaly.
Effectively given spaces

Abstract The theory of domains has been presented in various formalisms. The purpose of this paper is to show how to use the ideas in effectively given domains to formalize a theory of effectively given T0 spaces. In an effectively given space, there are two equivalent formulations of the notion of a computable object, an operational one and a topological one. The operational notion may be viewed as an implementation of the topological notion.
A flexible approach to synthetic lipid ammonium salts for polynucleotide transfection

Abstract The synthesis of novel 2,3-acyloxy-1-propylammonium salts is described. The route incorporates the use of glycidol and N-methyl-2-aminoethanol to prepare cationic lipids with control of absolute stereochemistry and regioselective introduction of fatty acid side chains.
A Possible Detection of M31* with Chandra

Two independent sets of Chandra and HST images of the nuclear region of M31 allow registration of X-ray and optical images to ~01. This registration shows that none of the bright (~1037 ergs s-1) X-ray sources near the nucleus is coincident with the central supermassive black hole, M31*. A 50 ks Chandra HRC image shows 2.5 ? evidence for a faint (~1036 ergs s-1) discrete source that is consistent with the position of M31*. The Bondi radius of M31* is 09, making it one of the few supermassive black holes with a resolvable accretion flow. This large radius and the previous detections of diffuse X-ray-emitting gas in the nuclear region make M31* one of the most secure cases for a radiatively inefficient accretion flow and place some of the most severe constraints on the radiative processes in such a flow.
Wingbeat Shape Modulation for Flapping-Wing Micro-Air-Vehicle Control During Hover

A new method of controlling a flapping-wing micro air vehicle by varying the velocity profiles of the wing strokes is presented in this manuscript. An exhaustive theoretical analysis along with simulation results show that this new method, called split-cycle constant-period frequency modulation, is capable of providing independent control over vertical and horizontal body forces as well as rolling and yawing moments using only two physical actuators, whose oscillatory motion is defined by four parameters. An actuated bob-weight is introduced to enable independent control of pitching moment. A general method for deriving sensitivities of cycle-averaged forces and moments to changes in wingbeat kinematic parameters is provided, followed by an analytical treatment for a case where the angle of attack of each wing is passively regulated and the motion of the wing spar in the stroke plane is driven by a split-cycle waveform. These sensitivities are used in the formulation of a cycle-averaged control law that successfully stabilizes and controls two different simulation models of the aircraft. One simulation model is driven by instantaneous aerodynamic forces derived from blade-element theory, while the other is driven by an empirical representation of an unsteady aerodynamic model that was derived from experiments.
The Photoelectric and Optical Properties of Sodium and Barium

Experimental spectral distribution curves have been obtained for sodium and barium using polarized and unpolarized radiation. The work function of sodium was determined as 2.28 ev and that of barium as 2.48 ev. The experimental data are compared with the theory of Mitchell. The theory fails satisfactorily to account for the absolute photoelectric yields and for the ratio of the photoelectric yields obtained with radiation polarized parallel and perpendicular to the plane of incidence.
Synthesis and resolution of a novel chiral diamine ligand and application to asymmetric lithiation-substitution

A short, efficient synthesis of chiral 1,5-diaza-cis-decalins (7) is presented. In the lithiation of N-Boc pyrrolidine, the ligands with the smallest most electron rich R groups (Me > Et > CH2tBu > CH2CF3 ≈ Bn) were most effective. In the asymmetric deprotonation/substitution of benzylic substrates, (R,R)-7 (R = Me, R‘ = H) conferred modest selectivity. The ready availability of both enantiomers of the 1,5-diaza-cis-decalins and the ability to tune steric and electronic properties renders these compounds an attractive new class of diamine ligands.
Use does not wear ragged the fabric of friendship: Thinking of objects as alive makes people less willing to replace them

Abstract Anthropomorphic beliefs about objects lead people to treat them as if they were alive. Two experiments test how anthropomorphic thought affects consumers' product replacement intentions. Consumers induced to think about their car in anthropomorphic terms (i) were less willing to replace it and (ii) gave less weight to its quality when making replacement decisions. Instead, they (iii) attended to (experimentally induced connotations of) the car's “warmth,” a feature usually considered relevant in the interpersonal domain. While anthropomorphic beliefs about brands are often seen as advantageous by marketers because they increase brand loyalty, similar beliefs about products may be less desirable.
An efficient all-parses systolic algorithm for general context-free parsing

The problem of outputting all parse trees of a string accepted by a context-free grammar is considered. A systolic algorithms is presented that operates inO(m·n) time, wherem is the number of distinct parse trees andn is the length of the input. The systolic array usesn2 processors, each of which requires at mostO(logn) bits of storage. This is much more space-efficient that a previously reported systolic algorithm for the same problem, which requiredO(n logn) space per processor. The algorithm also extends previous algorithms that only output a single parse tree of the input.
Cathode Sheath Voltage Models for Hydrazine Arcjets

We present two different approaches to predict the cathode sheath potential necessary to account for the total voltage in a 1-kW hydrazine arcjet operating at 10 A, 50 mg/s. The first approach is a jump condition cathode sheath model, which treats the cathode surface conditions and properties at the sheath edge. The input of the sheath model includes attachment area and the temperature at the cathode, and the near-cathode bulk plasma properties, which are obtained from a nonequilibrium arcjet model. The sheath potential from the sheath model is approximately -30 V for a pure tungsten cathode with 2 x 10 -8 m 2 attachment area, and 3680 K cathode tip temperature. The second approach is a detailed nonneutral plasma cathode sheath model, which employs Poisson's equation to calculate the charge distribution in the sheath and Saha's equilibrium equation to calculate species densities in the ionization region. The sheath voltage, electron temperature, and electron number density predictions from the two cathode models agree well. However, the cathode surface electric field differs by a factor of 10 or more
Role(s) of adsorbed water in the surface chemistry of environmental interfaces

The chemistry of environmental interfaces such as oxide and carbonate surfaces under ambient conditions of temperature and relative humidity is of great interest from many perspectives including heterogeneous atmospheric chemistry, heterogeneous catalysis, photocatalysis, sensor technology, corrosion science, and cultural heritage science. As discussed here, adsorbed water plays important roles in the reaction chemistry of oxide and carbonate surfaces with indoor and outdoor pollutant molecules including nitrogen oxides, sulfur dioxide, carbon dioxide, ozone and organic acids. Mechanisms of these reactions are just beginning to be unraveled and found to depend on the details of the reaction mechanism as well as the coverage of water on the surface. As discussed here, adsorbed water can: (i) alter reaction pathways and surface speciation relative to the dry surface; (ii) hydrolyze reactants, intermediates and products; (iii) enhance surface reactivity by providing a medium for ionic dissociation; (iv) inhibit surface reactivity by blocking sites; (v) solvate ions; (vi) enhance ion mobility on surfaces and (vii) alter the stability of surface adsorbed species. In this feature article, drawing on research that has been going on for over a decade on the reaction chemistry of oxide and carbonate surfaces under ambient conditions of temperature and relative humidity, a number of specific examples showing the multi-faceted roles of adsorbed water are presented.
Electrical Characterization of CdS Passivation on InP

InP surface passivation has been realized by a convenient chemical bath deposition (CBD) of a thin CdS layer. For comparison, samples without any treatments and/or with only a thin SiO2 layer were also prepared. Also studied was the effect of a thin layer of SiO2 deposited immediately after the CdS deposition. Schottky contacts were made on the CdS-passivated InP by electron-beam deposition of Ti/Au. Electrical characterization was conducted by current-voltage (I-V) and current-voltage-temperature (I-V-T) measurements. It was found that the electrical performance of the Schottky contacts of the CdS-passivated InP samples was improved significantly. The thickness (deposition time) of the CdS strongly affects the device electrical performance. The additional SiO2-on-CdS layer plays a key role in the process of InP surface passivation. Post-treatment in the CdS deposition process also strongly affects the surface morphology and electrical properties. Surface morphology studied by atomic force microscopy (AFM) indicates that the surface roughness increased after CdS deposition, though the degree of roughness is reverse proportional to the CdS process time. X-ray photoelectron spectroscopy (XPS) shows that the CdS layer protects the InP substrate during the oxide deposition.
On Finite-Length Performance of Polar Codes: Stopping Sets, Error Floor, and Concatenated Design

This paper investigates properties of polar codes that can be potentially useful in real-world applications. We start with analyzing the performance of finite-length polar codes over the binary erasure channel (BEC), while assuming belief propagation as the decoding method. We provide a stopping set analysis for the factor graph of polar codes, where we find the size of the minimum stopping set. We also find the girth of the graph for polar codes. Our analysis along with bit error rate (BER) simulations demonstrate that finite-length polar codes show superior error floor performance compared to the conventional capacity-approaching coding techniques. In order to take advantage from this property while avoiding the shortcomings of polar codes, we consider the idea of combining polar codes with other coding schemes. We propose a polar code-based concatenated scheme to be used in Optical Transport Networks (OTNs) as a potential real-world application. Comparing against conventional concatenation techniques for OTNs, we show that the proposed scheme outperforms the existing methods by closing the gap to the capacity while avoiding error floor, and maintaining a low complexity at the same time.
Vibrational spectra and structure, ab initio calculations, and conformational stability of 2-methylpropanal

Abstract The Raman spectra (3600-10 cm −1 ) of gaseous, liquid and solid and the infrared spectra (3600- 40 cm −1 ) of gaseous and solid 2-methylpropanal (isobutyraldehyde), (CH 3 ) 2 CHCHO, and the corresponding deuterium compound (CD 3 ) 2 CDCHO have been recorded. Additionally, qualita- tive depolarization ratios have been obtained from the Raman spectra of the liquids. These data have been interpreted for the fluid phases, showing that the gauche conformation (oxygen atom eclipsing a methyl group) is thermodynamically preferred over the high energy trans conformation (oxygen atom eclipsing the secondary hydrogen) and is the only rotamer present in the spectra of the annealed solids. From the relative intensities of the Raman lines of the liquid at 633 cm −1 (gauche) and 551 cm −1 (trans) as a function of temperature, the enthalpy difference is found to be 440±17 cm −1 (1.26±0.05 kcal mol −1 ). Utilizing rotational constants from previously reported microwave data and structural parameters obtained from ab initio calculations, the r 0 structural parameters are reported for both rotameric forms. The ab initio and r 0 structures for the gauche conformer are consistent with nonequivalent CC bond distances for the isopropyl moiety. A complete vibrational assignment is proposed which is based on infrared band contours, depolarization values, isotopic shifts and group frequencies. The structural parameters, conformational stabilities, barriers to internal rotation, and fundamental vibrational frequencies which have been determined experimentally are compared to those obtained from ab initio Hartree-Fock gradient calculations utilizing both the 3-21G and 6-31G* basis sets, and to the corresponding quantities obtained for some similar molecules.
The Effects of Revictimization on Coping and Depression in Female Sexual Assault Victims

To examine the effects of being revictimized, 555 women completed 2 mail surveys 1 year apart, reporting their experiences of sexual assault, the strategies they used to cope with those experiences, and feelings of depression. Path analyses, controlling for baseline coping and depression, revealed that those who were revictimized during the study reported using more maladaptive and adaptive coping strategies than did those who were not revictimized (β = .11 and β = .16, respectively). Further, women who were revictimized reported more depression than others (β = .15). This effect was explained in part by revictimized women's increased maladaptive coping. Results are consistent with other research showing that all of women's traumatic experiences must be taken into consideration to understand fully how sexual assault influences women's coping and recovery.
The Sizes of 1720 MHz OH Masers: VLBA and MERLIN Observations of the Supernova Remnants W44 and W28

We have used the NRAO Very Long Baseline Array (VLBA) to image OH (1720 MHz) masers in the supernova remnants (SNR) W28 and W44 at a resolution of 40 mas. We also used MERLIN to observe the same OH (1720 MHz) masers in W44 at a resolution of 290 ? 165 mas. All the masers are resolved by these VLBA and MERLIN observations. The measured sizes range from 50 to 180 mas and yield brightness temperature estimates from 0.3 to 20 ? 108 K. We investigate whether these measured angular sizes are intrinsic and hence originate as a result of the physical conditions in the supernova remnant shock, or whether they are scatter-broadened sizes produced by the turbulent ionized gas along the line of sight. While the current data on the temporal and angular broadening of pulsars, masers, and extragalactic sources toward W44 and W28 can be understood in terms of scattering, we cannot rule out that these large sizes are intrinsic. Recent theoretical modeling by Lockett, Gauthier, & Elitzur suggests that the physical parameters in the shocked region are indicative of densities and OH abundances that lead to estimates of sizes as large as what we have measured. If the sizes and structure are intrinsic, then the OH (1720 MHz) masers may be more like the OH (1612 MHz) masers in circumstellar shells than OH masers associated with H II regions. At two locations in W28 we observe the classical S-shapes in the Stokes V profiles caused by Zeeman splitting and use it to infer magnetic fields of order 2 mG.
Direct formation of functionalized ketones via the coupling of functionalized organocopper reagents with acid chlorides

Abstract Highly reactive copper solutions have been prepared by the lithium naphthalide reduction of a copper(I) iodide/triphenyl-phosphine complex. These copper solutions react rapidly with functionalized alkyl halides to give organocopper reagents which have been effectively trapped with acid chlorides giving functionalized ketones in good yields. Ester, nitrile, chloride, remote epoxide, and, to some degree, ketone groups can be tolerated by this approach.
Infinite N phase transitions in continuum Wilson loop operators

We define smoothed Wilson loop operators on a four dimensional lattice and check numerically that they have a finite and nontrivial continuum limit. The continuum operators maintain their character as unitary matrices and undergo a phase transition at infinite N reflected by the eigenvalue distribution closing a gap in its spectrum when the defining smooth loop is dilated from a small size to a large one. If this large N phase transition belongs to a solvable universality class one might be able to calculate analytically the string tension in terms of the perturbative Λ-parameter. This would be achieved by matching instanton results for small loops to the relevant large-N-universal function which, in turn, would be matched for large loops to an effective string theory. Similarities between our findings and known analytical results in two dimensional space-time indicate that the phase transitions we found only affect the eigenvalue distribution, but the traces of finite powers of the Wilson loop operators stay smooth under scaling.
Sounds that make you smile and share: a phonetic key to prosociality and engagement

The importance of names has been demonstrated for decision making related to individuals as well as companies. While previous researchers have focused on traits such as the fluency of names, we present three studies that focus on the role of the “hard e” or [ē] sound in relation to helping behavior. Because pronunciation of the [ē] sound requires a facial movement that mimics a smile particularly when the sound occurs at the end of a name, our research complements previous findings generated by the theory of embodied cognition in which biting on a pencil or chopstick evoked behavioral and mood changes. Study 1 finds that participants are more likely to help someone whose name ends with the [ē] sound while study 2 utilizes a broader set of contrasting sounds and finds a basic preference for the [ē] sound that is specific to women. Study 3 shows that women are significantly more likely to recall addressing their parents as Mommy or Daddy when soliciting help rather than Mom or Dad. Our findings complement previous research concerning motherese and highlight a phonetic cue for prosocial behavior that appears to offer insights for marketing and management. Just as the current studies are important in understanding interpersonal interactions, the findings have direct relevance for marketing campaigns that focus on consumer engagement.
Minimum complexity pursuit: Stability analysis

A host of problems involve the recovery of structured signals from a dimensionality reduced representation such as a random projection; examples include sparse signals (compressive sensing) and low-rank matrices (matrix completion). Given the wide range of different recovery algorithms developed to date, it is natural to ask whether there exist “universal” algorithms for recovering “structured” signals from their linear projections. We recently answered this question in the affirmative in the noise-free setting. In this paper, we extend our results to the case of noisy measurements.
Mixed H 2 / H ∞ control for discrete-time systems via convex optimization

Abstract A mixed H 2 H ∞ control problem for discrete-time systems is considered, where an upper bound on the H 2 norm of a closed loop transfer matrix is minimized subject to an H ∞ constraint on another closed loop transfer matrix. Both state-feedback and output-feedback cases are considered. It is shown that these problems are equivalent to finite-dimensional convex programming problems. In the state-feedback case, nearly optimal controllers can be chosen to be static gains. In the output feedback case, nearly optimal controllers can be chosen to have a structure similar to that of the central single objective H ∞ controller. In particular, the state dimension of nearly optimal output-feedback controllers need not exceed the plant dimension.
Non-universality effects and dark matter in gravity mediated SUSY breaking

Abstract Dark matter detection rates for supergravity models with R parity where supersymmetry is broken at a scale ≳ M G are discussed. Non-universal soft breaking masses in both the Higgs and squark sectors are considered, and it is seen that these can effect rates by a factor of 10 – 100 when m χ ∼ 1 0 ≳ 65 GeV ( χ 1 0 = lightest neutralino) but otherwise make relatively small corrections. The b → s + γ branching ratio is seen to correlate with detector event rates, large (small) branching ratios corresponding to small (large) event rates. Effects of precision determinations of cosmological parameters or event rate predictions by future satellite experiments are discussed for the ΛCDM and the ΦCDM models.
Error compensation algorithm for patient positioning robotics system

Surgeons in various medical areas (orthopedic surgery, neurosurgery, dentistry etc.) are using motor-driven drilling tools to make perforations in hard tissues (bone, enamel, dentine, cementum etc.) When the penetration requires very precise angles and accurate alignment with respect to different targets, precision cannot be obtained by using visual estimation and hand-held tools. Robots have been designed to allow for very accurate relative positioning of the patient and the surgical tools, and in certain classes of applications the location of bone target and inclination of the surgical tool can be accurately specified with respect to an inertial frame of reference. However, patient positioning errors as well as position changes during surgery can jeopardize the precision of the operation, and drilling parameters have to be dynamically adjusted. In this paper the authors present a quantitative method to evaluate the corrected position and inclination of the drilling tool, to account for translational and rotational errors in displaced target position. The compensation algorithm applies principles of inverse kinematics wherein a faulty axis in space caused by the translational and rotational errors of the target position is identified with an imaginary true axis in space by enforcing identity through a modified trajectory. In the absence of any specific application, this algorithm is verified on Solid Works, a commercial CAD tool and found to be correct. An example problem given at the end vindicates this statement.
Strong gravitational lensing and dark energy

We investigate the statistics of gravitational lenses in flat, low-density cosmological models with different cosmic equations of state ω. We compute the lensing probabilities as a function of image separation θ using a lens population described by the mass function of Jenkins et al. and modeled as singular isothermal spheres on galactic scales and as Navarro, Frenk, and White halos on cluster scales. It is found that COBE-normalized models with ω > -0.4 produce too few arcsecond-scale lenses in comparison with the Jodrell-VLA Astrometric Survey (JVAS) and the Cosmic Lens All-Sky Survey (CLASS), a result that is consistent with other observational constraints on ω. The wide-separation (θ 4'') lensing rate is a particularly sensitive probe of both ω and the halo mass concentration. The absence of these systems in the current JVAS/CLASS data excludes highly concentrated halos in ω -0.7 models. The constraints can be improved by ongoing and future lensing surveys of greater than 105 sources.
X-Ray Spectra of Intermediate-Luminosity, Radio-loud Quasars

We present new hard X-ray spectra of three radio-loud active galactic nuclei (AGNs) of moderately high X-ray luminosity (LX ≈ 1045 ergs s-1; PKS 2349-01, 3C 323.1, and 4C 74.26) obtained with ASCA and BeppoSAX. The X-ray continua are described in all three cases with a power-law model with photon indices Γ ≈ 1.85, modified at low energies by absorption in excess of the galactic value, which appears to be due to neutral gas. At higher energies, an Fe Kα emission line is detected in PKS 2349-01 and 4C 74.26 and is tentatively detected in 3C 323.1. The equivalent widths of the lines are consistent, albeit within large uncertainties, with the values for radio-quiet AGNs of comparable X-ray luminosity. The Fe Kα line is unresolved in 4C 74.26. In the case of PKS 2349-01, however, the inferred properties of the line depend on the model adopted for the continuum: if a simple power-law model is used, the line is resolved at more than 99% confidence with a full width at half-maximum corresponding to approximately 50,000 km s-1 and a rest-frame equivalent width of 230 ± 120 eV; however, if a Compton "reflection" model is used, the line is found to be a factor of 2 weaker for an assumed full width at half-maximum of 50,000 km s-1. In 4C 74.26, a strong Compton "reflection" component is detected. Its strength suggests that the scattering medium subtends a solid angle of 2π to the illuminating source. Overall, the spectral indices of these radio-loud quasars are remarkably similar to those of their radio-quiet counterparts. On the other hand, if the absorber is indeed neutral, as our results suggest, this would be consistent with the typical properties of radio-loud AGNs.
Model analysis of vehicle trafficability with application to surface effect vehicles on sea ice fields

Abstract A statistical theory of trafficability is developed and applied to aid in prediction of surface effect vehicle behaviour on sea ice terrains. A technique based upon the theory of random functions is used to extract pertinent statistical parameters to describe the topography of sea ice.
Diverse developments in travel and tourism marketing: a thematic approach

Reviews developments in travel and tourism marketing as reflected by articles published in the Journal of Travel and Tourism Marketing over a four‐year period from the journal’s inception in 1992‐1995. Identifies five main themes (economic psychology, market segmentation and travel patterns, strategic marketing, technological advances and travel and tourism communications) and related subthemes that portray a pattern of diverse research and development relating to the practice of travel and tourism marketing.
A Monte Carlo Study of the Self-Assembly of Bacteriorhodopsin

Bacteriorhodopsin (BR) and specific lipid molecules self-assemble into a quasi two-dimensional lattice structure known as the purple membrane (PM). In the PM, BR molecules exist in a trimeric form with lipid molecules present in the space enclosed by each trimeric unit and in the inter-trimer space. These trimeric units, which have a roughly circular cross-section, are arranged in hexagonal patterns with long-ranged crystalline order. In this work, we investigate the self-assembly of BR in the PM via Monte Carlo simulations of a two-dimensional model of the membrane and proteins. The protein molecules are modeled as 120 degrees sectors of a circle and the lipid molecules enter into the model through effective protein-protein interactions. The sectors cannot overlap with each other, and in addition to this excluded volume interaction there are site-site attractive interactions between specific points of the proteins to mimic interactions between helices on the proteins and lipid-induced interactions. At low values of the attractive well depth, the proteins are found in the monomeric form at all concentrations. At moderate and high values of the attractive well depth, trimers are formed as the concentration increases, and with a further increase in concentration the trimers organize into a hexagonal lattice. The interactions between the proteins and those induced by the intra-trimer lipids play an equally important role in the formation of trimers and the lattice. The lipids in the inter-trimer space cause the trimers to orient in a specific direction in the hexagonal crystal lattice.
On the Stability of Thin-Shell Wormholes in Noncommutative Geometry

This paper reexamines a special class of thin-shell wormholes that are unstable in general relativity in the framework of noncommutative geometry. It is shown that, as a consequence of the intrinsic uncertainty, these wormholes are stable to small linearized radial perturbations. Several different spacetimes are considered.
Leveraging limited research and development (R&D) resources in the public sector

Mission-directed public-sector research facilities are experiencing increasingly severe budget environments while seeing expanding missions and responsibilities. In an effort to identify research leveraging methodologies an information search was conducted in conjunction with some efforts to find the proper links to systems engineering fundamentals. The result is an initial model for use in a pre-concept/phase-1 engineering design organization, with a goal of improving the organizations performance.
Real-time frequency and 2-D angle estimation with sub-Nyquist spatio-temporal sampling

An algorithm is presented for real-time estimation of the frequency and azimuth and elevation angles of each signal incident on an airborne antenna array system over a very wide frequency band (2-18 GHz) commensurate with electronic signal warfare. The algorithm provides unambiguous frequency estimation despite severe temporal undersampling necessitated by cost/complexity of hardware considerations. The 2-18 GHz spectrum is decomposed into 1-GHz bands. The baseband output of each antenna is sent through two 250-MHz sampled channels where one is delayed relative to the other (prior to sampling) by 0.5 ns, which is the Nyquist interval for a 1-GHz bandwidth. Due to the high variance of the Direct ESPRIT frequency estimator, aliased frequencies are estimated via a simple formula and translated to the proper aliasing zone, utilizing eigenvector information generated by PRO-ESPRIT. The algorithm also provides unambigous 2-D angle estimate over the entire 2-18 GHz bandwidth, despite severe spatial undersampling at the higher end of this band necessitated by mutual coupling considerations and resolving power requirements at the lower end of the band. Eigenvector information generated by PRO-ESPRTT is used to facilitate computationally simple estimation of azimuth and elevation angles that are automatically paired with corresponding frequency estimates despite aliasing. Simulations are presented demonstrating the capabilities of the algorithm. >
Adaptive Mallow's optimization for weighted median filters

This work extends the idea of spectral optimization for the design of Weighted Median filters and employ adaptive filtering that updates the coefficients of the FIR filter from which the weights of the median filters are derived. Mallows' theory of non-linear smoothers [1] has proven to be of great theoretical significance providing simple design guidelines for non-linear smoothers. It allows us to find a set of positive weights for a WM filter whose sample selection probabilities (SSP's) are as close as possible to a SSP set predetermined by Mallow's. Sample selection probabilities have been used as a basis for designing stack smoothers as they give a measure of the filter's detail preserving ability and give non-negative filter weights. We will extend this idea to design weighted median filters admitting negative weights. The new method first finds the linear FIR filter coefficients adaptively, which are then used to determine the weights of the median filter. WM filters can be designed to have band-pass, high-pass as well as low-pass frequency characteristics. Unlike the linear filters, however, the weighted median filters are robust in the presence of impulsive noise, as shown by the simulation results.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Mozambique's infrastructure : a continental perspective

In the last 10 years, Mozambique's economy has grown steadily at an impressive rate of 7.7 percent per year, driven by the service sector, light industry, and agriculture. This pace is expected to continue or even increase with the massive influx of already-planned investment on the order of $15-20 billion. Mozambique's infrastructure is well developed in some sectors, including its east-west transport infrastructure, power grid, and water and sanitation networks. But the nation still faces critical challenges in these and other areas, including developing north-south transport connections, properly managing the water system, and expanding hydroelectric generation to meet potential. Mozambique spent about $664 million per year on infrastructure during the late 2000s, with as much as $204 million lost annually to inefficiencies. Comparing spending needs with existing spending and potential efficiency gains leaves an annual funding gap of $822 million per year. Mozambique could reduce inefficiency losses by positioning itself as a key power exporter. The country could reach infrastructure targets in 20 years through a combination of increased finance, improved efficiency, and cost-reducing innovations.
Systematic investigation of the alpha parameter influence on the critical feedback level in QD lasers

The dramatic variation in the linewidth enhancement factor (αΗ-factor) that has been reported for quantum dot lasers makes them an interesting subject for optical feedback studies. A low αΗ-factor combined with a high damping factor is especially interesting because it should increase the tolerance to optical feedback in these devices and may offer potential advantages for direct modulation. In the particular case of QD lasers, the carrier density is not clearly clamped at threshold. The lasing wavelength can switch from the ground state (GS) to the excited state (ES) as the current injection increases meaning that a carrier accumulation occurs in the ES even though lasing in the GS is still occurring. The filling of the ES inevitably enhances the αΗ-factor of the GS above threshold as experimentally and numerically shown. Consequently, this strong variation of the GS αΗ-factor in comparison to QW devices, should theoretically produce a significant variation in the onset of coherence collapse due to feedback. This coherence collapse regime, in which the laser is subject to instabilities, is incompatible with data transmission because of the induced high bit-error rate. One method to investigate the tolerance to optical feedback is to compare experiment with the theoretical work introduced by Petermann. It will be presented that under specific conditions, i.e., in the case of a strong enhancement in the αΗ-factor, the feedback sensitivity of the laser can vary by as much as 10dB within the same device.
Rigidity of limit sets for nonplanar geometrically finite Kleinian groups of the second kind

We consider the relation between geometrically finite groups and their limit sets in infinite-dimensional hyperbolic space. Specifically, we show that a rigidity theorem of Susskind and Swarup (Am J Math 114(2):233–250, 1992) generalizes to infinite dimensions, while a stronger rigidity theorem of Yang and Jiang (Bull Aust Math Soc 82(1):1–9, 2010) does not.
Nonquadratic cost and nonlinear feedback control

Nonlinear controllers offer significant advantages over linear controllers in a variety of circumstances. Hence there has been significant interest in extending linear-quadratic synthesis to nonlinear-nonquadratic problems. The purpose of this paper is to review the current status of such efforts and to present, in a simplified and tutorial manner, some of the basic ideas underlying these results. Our approach focuses on the role of the Lyapunov function in guaranteeing stability for autonomous systems on an infinite horizon. Sufficient conditions for optimality are given in a form that corresponds to a steady-state version of the Hamilton-Jacobi-Bellman equation. These results are used to provide a simplified derivation of the nonlinear feedback controller obtained by Bass and Webber (1966)38 and to obtain a deterministic variation of the stochastic nonlinear feedback controller developed by Speyer (1976).45.
Candidate Members and Age Estimate of the Family of Kuiper Belt Object 2003 EL61

The collisional family of Kuiper Belt object (KBO) 2003 EL61 opens the possibility for many interesting new studies of processes important in the formation and evolution of the outer solar system. As the first family in the Kuiper Belt, it can be studied using techniques developed for studying asteroid families, although some modifications are necessary. Applying these modified techniques allows for a dynamical study of the 2003 EL61 family. The velocity required to change orbits is used to quantitatively identify objects near the collision. A method for identifying family members that have potentially diffused in resonances (like 2003 EL61) is also developed. Known family members are among the very closest KBOs to the collision and two new likely family members are identified: 2003 UZ117 and 1999 OY3. We also give tables of candidate family members that require future observations to confirm membership. We estimate that a minimum of ~1 Gyr is needed for resonance diffusion to produce the current position of 2003 EL61, implying that the family is likely primordial. Future refinement of the age estimate is possible once (many) more resonant objects are identified. The ancient nature of the collision contrasts with the seemingly fresh surfaces of known family members, suggesting that our understanding of outer solar system surfaces is incomplete.
First Detection of PAHs and Warm Molecular Hydrogen in Tidal Dwarf Galaxies

We observed two faint tidal dwarf galaxies (TDGs), NGC 5291 N and NGC 5291 S, with the Infrared Spectrograph on the Spitzer Space Telescope. We detect strong polycyclic aromatic hydrocarbon (PAH) emission at 6.2, 7.7, 8.6, 11.3, 12.6, and 16.5 μm, which match models of groups of ~100 carbon atoms with an equal mixture of neutral and ionized PAHs. The TDGs have a dominant warm (~140 K) dust component in marked contrast to the cooler (40-60 K) dust found in starburst galaxies. For the first time we detect the low-J rotational lines from molecular hydrogen. Adopting LTE, there is ~105 M☉ of ~400 K gas, which is 3.2. Their disturbed morphologies suggest past merger events between companions; for example, NGC 5291 S has a projected 11 kpc tail. NGC 5291 N and S have stellar masses of (1.5 and 3.0) × 108 M☉, which is comparable to BCDs, although still roughly 10% of the LMC's stellar mass. The candidate TDGs are an order of magnitude less massive. This system appears to be a remarkable TDG nursery.
Answering General Time-Sensitive Queries

Time is an important dimension of relevance for a large number of searches, such as over blogs and news archives. So far, research on searching over such collections has largely focused on locating topically similar documents for a query. Unfortunately, topic similarity alone is not always sufficient for document ranking. In this paper, we observe that, for an important class of queries that we call time-sensitive queries, the publication time of the documents in a news archive is important and should be considered in conjunction with the topic similarity to derive the final document ranking. Earlier work has focused on improving retrieval for “recency” queries that target recent documents. We propose a more general framework for handling time-sensitive queries and we automatically identify the important time intervals that are likely to be of interest for a query. Then, we build scoring techniques that seamlessly integrate the temporal aspect into the overall ranking mechanism. We present an extensive experimental evaluation using a variety of news article data sets, including TREC data as well as real web data analyzed using the Amazon Mechanical Turk. We examine several techniques for detecting the important time intervals for a query over a news archive and for incorporating this information in the retrieval process. We show that our techniques are robust and significantly improve result quality for time-sensitive queries compared to state-of-the-art retrieval techniques.
Asynchronous Shared Memory Search Structures

We study the problem of storing an ordered set on an asynchronous shared memory parallel computer. We examine the case where we want to perform successor (least upper bound) queries efficiently on the set members that are stored. We also examine the case where processors insert and delete members of the set. Due to asynchrony, we require processors to perform queries and to maintain the structure independently. Although several such structures have been proposed, the analysis of these structures has been very limited. We here use the recently proposed QRQW PRAM model to provide upper and lower bounds on the performance of such data structures. In the asynchronous QRQW PRAM, the problem of processors concurrently and independently searching a shared data structure is very similar to the problem of routing packets through a network. Using this as a guide, we introduce the Search-Butterfly, a search structure that combines the efficient packet routing properties of the butterfly graph with the efficient search structure properties of the B-Tree. We analyze the behavior of the Search-Butterfly when the following operations are performed: arbitrary searches, random searches, and random searches, insertions, and deletions. We also provide lower bounds that show that the results are within a factor of O(\log n) of optimal where n is the number of keys in the structure. When the searches are random, the results are within a constant factor of optimal. Many of the proofs are derived from closely related results for packet routing. Others are of independent interest, most notably a method of adding queues to any network belonging to a large class of queuing networks with non-Markovian routing in a manner that allows us to bound the delay experienced by packets in the augmented network.
Use of medical, surgical and complementary treatments among women with fibroids

Objective To examine the use of medical management, uterus-preserving surgery (UPS), and complementary treatments among women with uterine fibroids.
Failure literacy in structural engineering

Abstract The history of the development of practice in many engineering disciplines is, in large part, the story of failures, both imminent and actual, and of the changes to designs, standards and procedures made as the result of timely interventions or forensic analyses. All engineers, and more particularly structural engineers, should be failure literate. Failure literacy means knowing about the critical historical failure cases that have shaped the profession: not merely the surface technical details, but the environment, the communications difficulties and the procedural issues. In the US, an intensive effort has been under way for nearly a decade to promote failure literacy in engineering education and practice. A number of educational resources have been developed to make it easier for engineering students and practicing engineers to learn from failures.