cssi/SciSciGPT-SciSciNet huggingface dataset:
An iteration partition approach for cache or local memory thrashing on parallel processing

Parallel processing systems with cache or local memory in the memory hierarchies are considered. These systems have a local cache memory in each processor and usually employ a write-invalidate protocol for the cache coherence. In such systems, a problem called 'cache or local memory thrashing' can arise in executions of parallel programs, when the data unnecessarily moves back and forth between the caches or local memories in different processors. An approach to eliminate, or at least to reduce, such movement for nested parallel loops is presented. It is based on relations between array element accesses and enclosed loop indexes in the loops. The relations can be used to assign processors to execute the appropriate iterations for parallel loops in the loop nests with respect to the data in their caches or local memories. An algorithm for calculating the correct iteration of the parallel loop in terms of loop indexes of the previous iterations executed in the processor is presented. This method benefits parallel code with nested loop structures in a wide range of applications. The experimental results show that the technique can achieve speedups up to 2. >
Increasing Returns and the Diffusion of Linux in China

China's unique combination of institutions, industries, and markets has fostered the generation and use of Linux-related innovations. Analyzing increasing returns provides key insight into this proliferation.
Loss Cone Refilling Rates in Galactic Nuclei

A gap in phase space is opened up by a binary supermassive black hole as it ejects stars in a galactic nucleus. This gap must be refilled before the single black hole that subsequently forms can disrupt or accrete stars. We compute loss cone refilling rates for a sample of elliptical galaxies as a function of the mass ratio of the binary that preceded the current, single black hole. Refilling times are of order 1010 yr or longer in bright elliptical galaxies. Tidal flaring rates in these galaxies might be much lower than predicted using steady state models.
A Sol-Gel-Based Approach to Synthesize High-Surface-Area Pt-Ru Catalysts as Anodes for DMFCs

A novel sol-gel based chemical process was developed to synthesize Pt-Ru catalysts possessing high specific surface area and good catalytic activity, for direct methanal fuel cells (DMFCs). In this process, tetramethylammonium hydroxide was used to hydrolyze platinum (II) acetylacetonate and ruthenium (III) acetylacetonate to form a homogeneous gel. Phase-pure powders possessing a high specific surface area as high as 136.9 m 2 /g were produced using controlled oxidizing atmospheres such as 1% O 2 balanced with N 2 . The resultant powder consisted of nanocrystalline Pt-Ru particles (less than 10 nm) and also revealed an excellent catalytic activity in standard three-electrode half-cell tests (cell potential of 0.295 V at currents of In(mA/gj) of 8), demonstrating the potential of the sol-gel-based processes for synthesizing high-performance catalysts for DMFCs. The key factor in obtaining phase-pure powders with high specific surface area is the controlled removal of carbon species in the as-prepared precursors. The rapid kinetics of carbon removal in air caused the growth of particles as well as the formation of Ru oxide, thus leading to a low specific surface area powder, combined with the segregation of Ru oxide from the homogeneous Pt-Ru precursors. A limited oxidizing ability of the heat-treatment atmospheres used such as 0.1% O 2 also yielded a low specific surface area powder due to the insufficient removal of carbon.
Double rulings for information brokerage in sensor networks

We study the problem of information brokerage in sensor networks, where information consumers (sinks, users) search for data acquired by information producers (sources). In-network storage such as geographical hash table (GHT) has been proposed to store data at rendezvous nodes for consumers to retrieve. In this paper, we propose a double rulings scheme that stores data replicas on a curve instead of one or multiple isolated sensors. The consumer travels along another curve that is guaranteed to intersect the producer curve. The double rulings is a natural extension of the flat hashing scheme such as GHTs. It has improved query locality--i.e., consumers close to producers find the data quickly--and structured aggregate queries, i.e., a consumer following a curve is able to retrieve all the data. Furthermore, by the flexibility of retrieval mechanisms, we have better routing robustness (as multiple retrieval paths are available) and data robustness against regional node failures. We show by simulation that the double rulings scheme provides reduced communication costs and more balanced traffic load on the sensors.
Measurement of dijet photoproduction at high transverse energies at HERA

The cross section for dijet photoproduction at high transverse energies is presented as a function of the transverse energies and the pseudorapidities of the jets. The measurement is performed using a sample of ep-interactions corresponding to an integrated luminosity of 6.3 pb $^{-1}$ , recorded by the ZEUS detector. Jets are defined by applying a $k_T$ -clustering algorithm to the hadrons observed in the final state. The measured cross sections are compared to next-to-leading order QCD calculations. In a kinematic regime where theoretical uncertainties are expected to be small, the measured cross sections are higher than these calculations.
House allocation with fractional endowments

This paper studies a generalization of the well known house allocation problem in which agents may own fractions of different houses summing to an arbitrary quantity, but have use for only the equivalent of one unit of a house. It departs from the classical model by assuming that arbitrary quantities of each house may be available to the market. Justified envy considerations arise when two agents have the same initial endowment, or when an agent is in some sense disproportionately rewarded in comparison to her peers. For this general model, an algorithm is designed to find a fractional allocation of houses to agents that satisfies ordinal efficiency, individual rationality, and no justified envy. The analysis extends to the full preference domain. Individual rationality, ordinal efficiency, and no justified envy conflict with weak strategyproofness. Moreover, individual rationality, ordinal efficiency and strategyproofness are shown to be incompatible. Finally, two reasonable notions of envy-freeness, no justified envy and equal-endowment no envy, conflict in the presence of ordinal efficiency and individual rationality. All of the impossibility results hold in the strict preference domain.
Stability Margin Scaling Laws for Distributed Formation Control as a Function of Network Structure

We describe a methodology for modeling, analysis and distributed control design of a large vehicular formation whose information graph is a D-dimensional lattice. We derive asymptotic formulae for the closed-loop stability margin based on a partial differential equation (PDE) approximation of the formation. We show that the exponent in the scaling law for the stability margin is influenced by the structure of the information graph and by the control architecture (symmetric or asymmetric). For a given fixed number of vehicles, we show that the scaling law can be improved significantly by employing a higher dimensional information graph and/or by introducing small asymmetry (mistuning) in the nominally symmetric proportional control gains. We also provide a characterization of the error introduced by the PDE approximation.
Structure of pairs in heavy weakly-bound nuclei

Abstract We study the structure of nucleon pairs within a simple model consisting of a square well in three dimensions and a delta-function residual interaction between two weakly-bound particles at the Fermi surface. We include the continuum by enclosing the entire system in a large spherical box. To a good approximation, the continuum can be replaced by a small set of optimally-determined resonance states, suggesting that in many nuclei far from stability it may be possible to incorporate continuum effects within traditional shell-model based approximations.
Law and economics in the tropics: Some reflections

Abstract Since the institutional, political, and behavioural contexts as well as the underlying power distributions are often different in poor countries, as spelled out in this paper, the law and economics literature as developed in rich countries needs to be seriously modified if it is to be of relevance to former countries.
NePalTM: design and implementation of nested parallelism for transactional memory systems

We present the programming model, design and implementation of NePalTM; a transactional memory system where atomic blocks can be used for concurrency control at an arbitrary level of nested parallelism.
A solution-phase, precursor route to polycrystalline SnO2 nanowires that can be used for gas sensing under ambient conditions.

This paper describes a solution-based, precursor method for the facile synthesis of uniform nanowires containing rutile SnO2 nanocrystallites. In a typical procedure, nanowires of ∼50 nm in diamete...
Designing object-oriented representations for reasoning from first-principles

Modeling expert knowledge using 'situation-action' rules is not always feasible in knowledge intensive involving volatile knowledge. In such domains, the size and the dynamic nature of the search space make it extremely difficult to setup a rule base and keep it accurate. An alternative approach suggests that in some domain many of the rules that experts use can be derived by reasoning from 'first-principles'. That approach entails modeling experts' deep knowledge, and emulating the reasoning processes with deep knowledge that allow experts to derive many rules and their justification. The author discusses the design and implementation of an object-oriented representation for the deep knowledge traders utilize in a business domain called hedging, which is knowledge intensive and involves volatile knowledge. He illustrates how deep knowledge modeled using that representation is used to support reasoning from first-principles. The author also analyzes features of that representation that were found to be beneficial in the development of a knowledge-based system called INTELLIGENT-HEDGER. >
Toroidalization of locally toroidal morphisms from N-folds to surfaces

The toroidalization conjecture of D. Abramovich, K. Karu, K. Matsuki, and J. Wlodarczyk asks whether any given morphism of nonsingular varieties over an algebraically closed field of characteristic zero can be modified into a toroidal morphism. Following a suggestion by Dale Cutkosky, we define the notion of locally toroidal morphisms and ask whether any locally toroidal morphism can be modified into a toroidal morphism. In this paper, we answer the question in the affirmative when the morphism is between any arbitrary variety and a surface.
Regression approach to combination of decisions by multiple character recognition algorithms

A regression method is proposed to combine decisions of multiple character recognition algorithms. The method computes a weighted sum of the rank scores produced by the individual classifiers and derive a consensus ranking. The weights are estimated by a logistic regression analysis. Two experiments are discussed where the method was applied to recognize degraded machine-printed characters and handwritten digits. The results show that the combination outperforms each of the individual classifiers.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
An Alternative to API 14E Erosional Velocity Limits for Sand-Laden Fluids

The current practice for eliminating erosional problems in piping systems is to limit the flow velocity (V e ) to that established by the recommended practice API RP 14E based on an empirical constant (C-factor) and the fluid mixture density (ρ m ) as follows:V e =C/√ρ m . The API criterion is specified for clean service (noncorrosive and sand-free), and it is noted that the C-factor should be reduced if sand or corrosive conditions are present. The validity of the equation has been challenged on the basis that the API RP 14E limits on the C-factor can be very conservative for clean service and is not applicable for conditions when corrosion or sand are present. Extensive effort has been devoted to develop an alternative approach for establishing erosional velocity limits for sand-laden fluids. Unfortunately, none of these proposals have been adopted as a standard practice because of their complexity. This paper will review the results of these studies and proposes an alternative equation that is as simple as the API 14E equation. This alternative equation has the following form: V e =SD√ρ m /√W The value of the S-factor depends on the pipe geometry, i.e., bend, tee, contraction, expansion, etc. Using the units for mixture flow velocity (V e ) in m/s, fluid mixture density (ρ m ) in kg/m 3 , pipe diameter (D) in mm and sand production (W) in kg/day, the value of the S-factor is 0.05 for pipe bends. The accuracy of the proposed equation for predicting erosion in pipe bends for fluids containing sand is demonstrated by a comparison with several multi-phase flow loop tests that cover a broad range of liquid-gas ratios and sand concentrations.
System-level design hardening based on worst-case ASET Simulations

We present experimental and simulation results on single-event transients in an analog subsystem for satellite electronic equipment. Investigations based on worst-case transient events, simulated with transistor-level circuit models, suggest design modifications for hardening.
Modeling the Panchromatic Spectral Energy Distributions of Galaxies

The spectral energy distributions (SEDs) of galaxies are shaped by nearly every physical property of the system, including the star-formation history, metal content, abundance pattern, dust mass, grain size distribution, star-dust geometry, and interstellar radiation field. The principal goal of stellar population synthesis (SPS) is to extract these variables from observed SEDs. In this review I provide an overview of the SPS technique and discuss what can be reliably measured from galaxy SEDs. Topics include stellar masses, star-formation rates and histories, metallicities and abundance patterns, dust properties, and the stellar initial mass function.
Eigenfaces vs. Fisherfaces: recognition using class specific linear projection

We develop a face recognition algorithm which is insensitive to large variation in lighting direction and facial expression. Taking a pattern classification approach, we consider each pixel in an image as a coordinate in a high-dimensional space. We take advantage of the observation that the images of a particular face, under varying illumination but fixed pose, lie in a 3D linear subspace of the high dimensional image space-if the face is a Lambertian surface without shadowing. However, since faces are not truly Lambertian surfaces and do indeed produce self-shadowing, images will deviate from this linear subspace. Rather than explicitly modeling this deviation, we linearly project the image into a subspace in a manner which discounts those regions of the face with large deviation. Our projection method is based on Fisher's linear discriminant and produces well separated classes in a low-dimensional subspace, even under severe variation in lighting and facial expressions. The eigenface technique, another method based on linearly projecting the image space to a low dimensional subspace, has similar computational requirements. Yet, extensive experimental results demonstrate that the proposed "Fisherface" method has error rates that are lower than those of the eigenface technique for tests on the Harvard and Yale face databases.
Ultrathin epitaxial graphite: 2D electron gas properties and a route toward graphene-based nanoelectronics.

We have produced ultrathin epitaxial graphite films which show remarkable 2D electron gas (2DEG) behavior. The films, composed of typically three graphene sheets, were grown by thermal decomposition on the (0001) surface of 6H−SiC, and characterized by surface science techniques. The low-temperature conductance spans a range of localization regimes according to the structural state (square resistance 1.5 kΩ to 225 kΩ at 4 K, with positive magnetoconductance). Low-resistance samples show characteristics of weak localization in two dimensions, from which we estimate elastic and inelastic mean free paths. At low field, the Hall resistance is linear up to 4.5 T, which is well-explained by n-type carriers of density 1012 cm-2 per graphene sheet. The most highly ordered sample exhibits Shubnikov−de Haas oscillations that correspond to nonlinearities observed in the Hall resistance, indicating a potential new quantum Hall system. We show that the high-mobility films can be patterned via conventional lithographic...
Analysis of Scheduled Latency Insensitive Systems with Periodic Clock Calculus

Originally the Latency Insensitive Protocols (LIP) were invented to make a system elastic to the interconnect latencies using handshaking signals such as `valid' and `stall'. Such protocols require extra signals leading to area overhead and may affect throughput of the system. To optimize away some of these overheads, scheduled LIPs were proposed which replaced the complex handshake control blocks by a central scheduling scheme. One can view a scheduled LIP based design as a system where within each strongly connected component of the system, the modules and the relay stations are scheduled by activation signals. These activation signals can be thought of as infinite sequence of `1's and `0's. If such sequences are periodic, one can view them as periodic clocks. Given the advances in periodic clock calculus in the synchronous programming context, in this paper, we analyze the LIP scheduling problem within the framework of periodic clock calculus. Such analysis provides straight forward algorithms to compute the throughput of scheduled LIP based systems. Within this framework, we also propose a method to synthesize fractional synchronizers. Fractional synchronizers are used to equalize cycles with different throughputs. Our method can determine the numbers and the scheduling sequences of such fractional synchronizers using the periodic clock calculus. In addition, we provide a static estimation of the required fractional synchronizers based only on the system's structure which is fast and accurate.
Market Integration Test for Pacific Egg Markets

This paper uses of Johansen's multivariate cointegration test to test for egg market integration of six Pacific states, Washington, Idaho, Oregon, California, Nevada, and Arizona. We conclude that eggs from these states substitute for each other to some degree, and arbitrage possibilities through trade bind the egg prices. In addition, the Law of One Price (LOP), the case of perfect integration, is examined by testing the linear combination of cointegration vectors. Test results show that the LOP is not satisfied even though the egg markets in the six Pacific states are highly integrated. Arizona egg prices, California egg prices, and Washington egg prices play dominant roles on the Pacific egg market in the long run.
A resonant wave theory

Analysis is used to show that a solution of the Navier–Stokes equations can be computed in terms of wave-like series, which are referred to as waves below. The mean flow is a wave of infinitely long wavelength and period; laminar flows contain only one wave, i.e. the mean flow. With a supercritical instability, there are a mean flow, a dominant wave and its harmonics. Under this scenario, the amplitude of the waves is determined by linear and nonlinear terms. The linear case is the target of flow-instability studies. The nonlinear case involves energy transfer among the waves satisfying resonance conditions so that the wavenumbers are discrete, form a denumerable set, and are homeomorphic to Cantor's set of rational numbers. Since an infinite number of these sets can exist over a finite real interval, nonlinear Navier–Stokes equations have multiple solutions and the initial conditions determine which particular set will be excited. Consequently, the influence of initial conditions can persist forever. This phenomenon has been observed for Couette–Taylor instability, turbulent mixing layers, wakes, jets, pipe flows, etc. This is a commonly known property of chaos.
Discretized Multinomial Distributions and Nash Equilibria in Anonymous Games

We show that there is a polynomial-time approximation scheme for computing Nash equilibria in anonymous games with any fixed number of strategies (a very broad and important class of games), extending the two-strategy result of Daskalakis and Papadimitriou 2007. The approximation guarantee follows from a probabilistic result of more general interest: The distribution of the sum of n independent unit vectors with values ranging over {e1,...,ek}, where ei is the unit vector along dimension i of the k-dimensional Euclidean space, can be approximated by the distribution of the sum of another set of independent unit vectors whose probabilities of obtaining each value are multiples of 1/z for some integer z, and so that the variational distance of the two distributions is at most eps, where eps is bounded by an inverse polynomial in z and a function of k, but with no dependence on n. Our probabilistic result specifies the construction of a surprisingly sparse epsi-cover- under the total variation distance - of the set of distributions of sums of independent unit vectors, which is of interest on its own right.
THREE-POINT CORRELATION FUNCTIONS OF SDSS GALAXIES: LUMINOSITY AND COLOR DEPENDENCE IN REDSHIFT AND PROJECTED SPACE

The three-point correlation function (3PCF) provides an important view into the clustering of galaxies that is not available to its lower order cousin, the two-point correlation function (2PCF). Higher order statistics, such as the 3PCF, are necessary to probe the non-Gaussian structure and shape information expected in these distributions. We measure the clustering of spectroscopic galaxies in the Main Galaxy Sample of the Sloan Digital Sky Survey, focusing on the shape or configuration dependence of the reduced 3PCF in both redshift and projected space. This work constitutes the largest number of galaxies ever used to investigate the reduced 3PCF, using over 220,000 galaxies in three volume-limited samples. We find significant configuration dependence of the reduced 3PCF at 3-27 h –1 Mpc, in agreement with ΛCDM predictions and in disagreement with the hierarchical ansatz. Below 6 h –1 Mpc, the redshift space reduced 3PCF shows a smaller amplitude and weak configuration dependence in comparison with projected measurements suggesting that redshift distortions, and not galaxy bias, can make the reduced 3PCF appear consistent with the hierarchical ansatz. The reduced 3PCF shows a weaker dependence on luminosity than the 2PCF, with no significant dependence on scales above 9 h –1 Mpc. On scales less than 9 h –1 Mpc, the reduced 3PCF appears more affected by galaxy color than luminosity. We demonstrate the extreme sensitivity of the 3PCF to systematic effects such as sky completeness and binning scheme, along with the difficulty of resolving the errors. Some comparable analyses make assumptions that do not consistently account for these effects.
Analysis of integrated millimeter-wave and submillimeter-wave waveguides using orthonormal wavelet expansions

A mixed spectral/space-domain integral formulation for the analysis of integrated planar dielectric waveguide structures with printed metallized sections is presented which exploits the newly developed multiresolution expansions based on the concepts of orthonormal wavelet theory. The proposed expansion basis, which is highly localized in both space and spectral domains, is entirely generated by the dilation and shifting of two closely related characteristic functions. It is demonstrated that using this type of expansion in the moment method solution of the integral equations leads to very sparsely populated moment matrices after performing a threshold procedure. Extensive numerical examples are provided for a variety of practical waveguide configurations. >
Optimality of Myopic Policies for Dynamic Lot-Sizing Problems in Serial Production Lines with Random Yields and Autoregressive Demand

We study lot-size policies in a serial, multistage manufacturing/inventory system with two key generalizations, namely 1 random yields at each production stage and 2 an autoregressive demand process. Previous research shows that the optimal policies in models with random yields even in models with a single installation lack the familiar order-up-to structure and are not myopic. Thus, dynamic programming algorithms are needed to compute optimal policies, and one encounters the “curse of dimensionality”; this is exacerbated here by the need to expand the size and dimension of the state space to accommodate the autoregressive demand feature. Nevertheless, although our model is more complex, we prove that there is an optimal policy with the order-up-to feature and, more importantly, that the optimal policy is myopic. This avoids the computational burden of dynamic programming. Our results depend on two assumptions concerning the stochastic yield, namely that the expected yield at a work station is proportional to the lot size, and the distribution of the deviation of the yield from its mean does not depend on the lot size. We introduce the concept of echelon-like variables, a generalization of Clark and Scarf's classical concept of echelon variables, to derive the structure of optimal policies. Furthermore, we show that the same kind of policy is optimal for several criteria: infinite-horizon discounted cost, infinite-horizon long-run average cost, and finite-horizon discounted cost with the appropriate choice of the salvage value function.
The Effect of Firms' Depreciation Method Choice on Managers' Capital Investment Decisions

This study examines whether straight‐line depreciation, relative to accelerated depreciation, causes non‐executive managers to make non‐value‐maximizing capital investment decisions. To do this, I conduct experiments in which managers must decide whether to continue using an existing asset or invest in a replacement asset. By design, replacing the existing asset yields higher cash flows and managers are aware of this fact. However, if the asset is replaced, then the greater remaining book value under straight‐line depreciation relative to accelerated depreciation causes earnings to be lower. Lower earnings and psychological forces may push managers of firms that use straight‐line depreciation away from making the economically efficient capital investment decision. The results suggest that managers of firms that use straight‐line depreciation are less likely to invest in a replacement asset than are managers of firms that use accelerated depreciation. Further, the results suggest that managers perceive tha...
A Classical MCMC Approach to the Estimation of Limited Dependent Variable Models of Time Series

Estimating limited dependent variable time series models through standard extremum methods can be a daunting computational task because of the need for integration of high order multiple integrals and/or numerical optimization of difficult objective functions. This paper proposes a classical Markov Chain Monte Carlo (MCMC) estimation technique with data augmentation that overcomes both of these problems. The asymptotic properties of the proposed estimator are discussed. Furthermore, a practical and flexible algorithmic framework for this class of models is proposed and is illustrated using simulated data, thus also offering some insight into the small-sample biases of such estimators. Finally, the proposed framework is used to estimate a dynamic, discrete-choice monetary policy reaction function for the United States during the Greenspan years.
Control of forward velocity for a simplified planar hopping robot

A simplified lossless model of the Raibert planar hopper is introduced for the purpose of analytically studying the control of forward velocity. A closed-form return map describing the robot's state at the next hop as a function of that at the current hop is derived. The Raibert forward velocity controller is introduced and the fixed points of the closed loop system are characterized as well as the stability of these points. A new control law inspired by this analysis is introduced and compared with the Raibert control law.
On the complexity of approximating a Nash equilibrium

We show that computing a relatively (i.e., multiplicatively as opposed to additively) approximate Nash equilibrium in two-player games is PPAD-complete, even for constant values of the approximation. Our result is the first constant inapproximability result for Nash equilibrium, since the original results on the computational complexity of the problem [Daskalakis et al. 2006a; Chen and Deng 2006]. Moreover, it provides an apparent---assuming that PPAD is not contained in TIME(nO(log n))---dichotomy between the complexities of additive and relative approximations, as for constant values of additive approximation a quasi-polynomial-time algorithm is known [Lipton et al. 2003]. Such a dichotomy does not exist for values of the approximation that scale inverse-polynomially with the size of the game, where both relative and additive approximations are PPAD-complete [Chen et al. 2006]. As a byproduct, our proof shows that (unconditionally) the sparse-support lemma [Lipton et al. 2003] cannot be extended to relative notions of constant approximation.
The Unimportance of Spending: How Fractionalization Affects School Performance

This note provides an historical example that appears to illustrate how racial fractionalization reduces school district academic performance. Hall and Leeson (AJES, forthcoming) find a negative relationship between racial fractionalization and school district performance in a sample of Ohio school districts. Holding school district spending constant, communities that are more racially heterogeneous have lower passage rates on state proficiency exams. This finding is surprising because the theoretical work of Alesina, Baqir, and Easterly (QJE, 1999) suggests that racial fractionalization will lead to poor public sector performance because of a decline in spending. While they show that racial fractionalization does lead to reduced spending on education, they do not look at whether that leads to reduced school performance. The empirical results of Hall and Leeson suggest that the negative effect of racial fractionalization does not operate through spending but through some other mechanism. The following example from the Cleveland suburb of Cleveland Heights, taken from the work of historian Marian Morton (Cleveland Heights: The Making of an Urban Suburb, 2002), shows one way that racial fractionalization could result in lower school performance independent of spending. Cleveland Heights is a good example of a racially-fractionalized school district, as it is known nationally for its Int Adv Econ Res (2010) 16:130–131 DOI 10.1007/s11294-009-9238-3
The Challenges of Hardware Synthesis from C-Like Languages

Many techniques for synthesizing digital hardware from C-like languages have been proposed, but none have emerged as successful as Verilog or VHDL for register-transfer-level design. Familiarity is the main reason C-like languages have been proposed for hardware synthesis. Synthesize hardware from C, proponents claim, and a C programmer can be turned into a hardware designer. Another common motivation is hardware/software codesign: today's systems usually contain a mix of hardware and software, and it is often unclear initially which portions to implement in hardware. Here, using a single language should simplify the migration task. The paper surveys several C-like hardware synthesis languages and looks at two of the fundamental challenges, concurrency and timing control.
A new graphic display/plotter for small digital computers

This report describes a new inexpensive cathode-raytube-display and recorder interface designed to provide graphical output for many of the increasingly popular small digital computers in the 12-to 24-bit class. Our original design was developed to produce differential-equation solutions, phase-plane plots, correlation functions, spectra, and amplitude distributions for on-line digital simulation with the 18-bit PDP-9; but the interface logic is flexible enough to serve many other computers and applications.
A fine pointing control for a large spinning spacecraft in earth orbit

A large spinning spacecraft in Earth orbit includes a rigidly mounted telescope, parallel to the spacecraft's intended spin-axis. The three principal moments-of-inertia are unequal. Electric thrustors are used to overcome the gravity-gradient torque components. Uncertainty of the spacecraft's inertia tensor, including misalignment of the telescope axis from the actual principal direction, as well as magnetic, solar pressure, and aerodynamic forces, produce disturbing torques which are constant or vary sinusoidally during a spin-rotation. The constant torques and the coefficients of the sinusoidal torques are modeled as first-order Markov processes and consequently increase the dimension of the dynamical state. Measurements of the spacecraft's orientation are assumed to be of 2 types: a) the deviation, measured continuously in body axes, of the telescope axis from its desired direction; b) the deviation of the telescope axis towards or away from certain bright stars, measured as the star in question crosses a slit on the outside of the spacecraft. The estimation of the orientation from measurements a) and b) involves not only linear dynamical equations with periodic coefficients but also a mixture of a continuous and a discrete periodic, information pattern. The usual estimation gains settle here into a periodic pattern. Quadratic synthesis of a control law produces constant and periodically varying feedback gains. The constant control gains are obtained by eigenvector decomposition, and the periodic control gains by solving a linear matrix differential equation with periodic forcing term. The method of "spectral factorization" is used to obtain the estimator gains.
Image-charge effects on the envelope dynamics of an unbunched intense charged-particle beam

The root-mean-squared (rms) envelope equations are derived and analyzed for an unbunched intense charged-particle beam in an alternating-gradient focusing field and a cylindrical conducting pipe. All higher-order image-charge effects from the cylindrical pipe are expressed in terms of so-called multiple moment factors in the rms beam envelope equations, and the multiple moment factors are evaluated. Numerical results show that for vacuum phase advance /spl sigma//sub /spl nu// < 90/spl deg/, the image-charge effects on the matched and slightly mismatched beam envelopes are negligibly small, at all orders, for all beams with arbitrary beam density profiles (including hollow density profiles) as well as for arbitrary small apertures (including beams with large aspect ratios). However, the main unstable region for the envelope evolution with image-charge effects, which occurs for 90/spl deg/ < /spl sigma//sub /spl nu// < 270/spl deg/, depending on the value of the normalized beam intensity SK / /spl epsiv/, is found to be narrower than its counterpart without image-charge effects.
National Trends in Surgery for Sinonasal Malignancy and the Effect of Hospital Volume on Short-Term Outcomes

Objectives/Hypothesis To characterize trends in the management of sinonasal malignancy with a focus on the impact of hospital volume on surgical outcomes. Study Design Retrospective cohort study. Methods Time trends were analyzed among patients admitted for surgical resection of sinonasal malignancy in the Nationwide Inpatient Sample (NIS) between 1988 and 2009. Subset analysis was performed on cohorts with skull base or orbital involvement or on cohorts who underwent neck dissection. Patient characteristics and hospital attributes were correlated with morbidity and mortality. Results Over 22 years, we identified 3,850 cases from 879 hospitals. A total of 24.3% of patients had complications and 0.8% of hospitalizations resulted in mortality. Cases with skull base or orbital involvement, or cases including neck dissection, had more complications and a longer length of stay. Prevalence of neck dissection increased over time. Thirty-two hospitals averaged more than five cases per year, accounting for 28% of all surgeries. These centers were large (73.3%), urban (96.7%), teaching (90%) institutions and performed more high-risk cases: 32.4% of neck dissections, 44.6% of orbital cases, and 43.1% of skull base cases. Compared to lower-volume centers, these centers had more cardiopulmonary and electrolyte complications, but no difference was observed in the lengths of stay. A greater proportion of cases were recently performed at high-volume centers. Conclusion Over time, complicated surgeries were more likely to occur at higher-volume hospitals without significant changes in surgical complication rates. High-volume centers had increased rates of cardiopulmonary and electrolyte complications, likely representing complex postoperative management, but these were not associated with higher mortality. Level of Evidence 2c. Laryngoscope, 124:1609–1614, 2014
Applications of exact solution for strongly interacting one-dimensional Bose-Fermi mixture : Low-temperature correlation functions, density profiles, and collective modes

Abstract We consider one-dimensional interacting Bose–Fermi mixture with equal masses of bosons and fermions, and with equal and repulsive interactions between Bose–Fermi and Bose–Bose particles. Such a system can be realized in current experiments with ultracold Bose–Fermi mixtures. We apply the Bethe ansatz technique to find the exact ground state energy at zero temperature for any value of interaction strength and density ratio between bosons and fermions. We use it to prove the absence of the demixing, contrary to prediction of a mean-field approximation. Combining exact solution with local density approximation in a harmonic trap, we calculate the density profiles and frequencies of collective modes in various limits. In the strongly interacting regime, we predict the appearance of low-lying collective oscillations which correspond to the counterflow of the two species. In the strongly interacting regime, we use exact wavefunction to calculate the single particle correlation functions for bosons and fermions at low temperatures under periodic boundary conditions. Fourier transform of the correlation function is a momentum distribution, which can be measured in time-of-flight experiments or using Bragg scattering. We derive an analytical formula, which allows to calculate correlation functions at all distances numerically for a polynomial time in the system size. We investigate numerically two strong singularities of the momentum distribution for fermions at k f and k f + 2 k b . We show, that in strongly interacting regime correlation functions change dramatically as temperature changes from 0 to a small temperature ∼ E f / γ ≪ E f , where E f = (π ℏn ) 2 /(2 m ), n is the total density and γ = mg /( ℏ 2 n ) ≫ 1 is the Lieb–Liniger parameter. A strong change of the momentum distribution in a small range of temperatures can be used to perform a thermometry at very small temperatures.
An X-Ray Dip in the X-Ray Transient 4U 1630–47

An X-ray dip was observed during a 1996 Rossi X-Ray Timing Explorer observation of the recurrent X-ray transient 4U 1630-47. During the dip, the 2-60 keV X-ray flux drops by a factor of about 3, and, at the lowest point of the dip, the X-ray spectrum is considerably softer than at nondip times. We find that the 4U 1630-47 dip is best explained by absorption of the inner part of an accretion disk, while the outer part of the disk is unaffected. The spectral evolution during the dip is adequately described by the variation of a single parameter, the column density obscuring the inner disk.
An edge gradient enhancing adaptive order statistic filter

We consider an adaptive order statistic (OS) filter that can enhance gradients of edges while suppressing impulsive and some nonimpulsive noise components. In particular, comparison and selection (CS) filters are introduced, in which the output is determined by comparing the sample mean and median values inside each window. It is shown theoretically that CS filters can enhance gradients of a variety of edges including noisy blurred ones. Some root properties of CS filters are also shown. Finally, experimental results are presented to illustrate the performance characteristics of these filters.
Graphics, problem solving and virtual systems

Man naturally uses many languages when he thinks creatively. Interactive computing mechanisms intended to augment man's higher faculties must provide for appropriate man-machine dialogues. The mechanisms must not constrain man's linguistic expressiveness for communication in the dialogues. To do so is to limit or retard the creative activity.
Conical geometry for sagittal focusing as applied to x rays from synchrotrons

We describe a method for simultaneously focusing and monochromatizing x rays from a fan of radiation having as high as 15-mrad divergence in one dimension. This geometry is well suited to synchrotron radiation sources at magnifications of 1/5 to 2 and is efficient for x-ray energies between 3 and 40 keV (0.48 and 6.4 fJ). The method uses crystals bent to part of a cone for sagittal focusing and permits the collection of a larger divergence with less mixing of the horizontal into the vertical divergence than is possible with x-ray mirrors. We describe the geometry required for achieving the highest efficiency when a conical crystal follows a flat crystal in a nondispersive two-crystal monochromator. At a magnification of 1/3, the geometry is identical to that of a cylindrical focusing design described previously [ Nucl. Instrum. Methods172, 237 ( 1980)]. A simple theoretical calculation is shown to agree well with ray-tracing results. Minimum aberrations are observed at magnifications near 1. Applications of the conical focusing geometry to existing and future synchrotron radiation facilities is discussed.
Renormalization Group and divergences

Application of asymptotic freedom to the ultraviolet stability in Euclidean quantum field theories is revisited and illustrated through the hierarchical model making also use of a few technical developments that followed the original works of Wilson on the renormalization group.
Crises and Recoveries in an Empirical Model of Consumption Disasters

We estimate an empirical model of consumption disasters using new data on consumption for 24 countries over more than 100 years, and study its implications for asset prices. The model allows for par tial recoveries after disasters that unfold over multiple years. We find that roughly half of the drop in consumption due to disasters is subsequently reversed. Our model generates a sizable equity premium from disaster risk, but one that is substantially smaller than in simpler models. It implies that a large value of the intertemporal elasticity of substitution is necessary to explain stock-market crashes at the onset of disasters. (JEL E21, E32, E44, G12, G14)
Numerical simulations of commercial aircraft wakes subjected to airport surface weather conditions

Using tower e yby data for validation, we have developed a two-dimensional numerical simulation of the ine uence of surface weather conditions on wake vortex motion and decay for representative commercial aircraft. Our simulations support the conjecture that the ratio of eddy viscosity to kinematic viscosity, appropriate for modeling aircraft wakes, scales linearly with circulation, which yields a nominally constant equivalent Reynolds number for all commercial aircraft sizes. We have tested the constant eddy viscosity approximation for three different aircraft types and six surface weather states, showing the utility of the approach in predicting wake vortex motion and decay. Subsequently, we have shown how data from one aircraft e ight test can be used to infer the decay behavior of another, and we have examined the ine uence of the six surface weather states on the vortex decay behavior predicted for a large commercial aircraft. Based upon these simulations, we have determined that the two-dimensional, constant eddy viscosity approach can be useful in assessing the ine uence of surface weather conditions on wake vortex decay.
Peptide bond formation via catalytic antibodies: Synthesis of a novel phosphonate diester hapten

Phosphonate diester 2, a hapten recently employed to induce the first monoclonal catalytic antibodies capable of catalyzing peptide bond formation, was synthesized via elaboration of scalemic α-amino phosphonate 4.
Black Sea and World Wheat Market Price Integration Analysis

In 2008–10, Russia and Ukraine together exported an average of 29 million tons of wheat per year, and have become important players in the international wheat market. This research summarizes the short- and long-run wheat price dynamics between Ukraine and Russia, and other major wheat exporters—the United States, European Union (EU), and Canada—from 2004 to 2010. Tests of market price co-integration (Johansen maximum likelihood test and residual-based tests) as well as threshold error correction techniques were performed for this purpose. The results suggest that Russian wheat prices were co-integrated with EU and U.S. wheat prices but not with Canadian wheat prices. Ukrainian wheat prices were found to be co-integrated with French wheat prices only. The estimated long-run wheat price transmission elasticities were estimated to be equal to 1.04 between Russian and French (a representative country of the EU) wheat prices, 1.16 between Russian and U.S. wheat prices, and 1.05 between Ukrainian and French wheat prices. We also found the short-term relationships between the co-integrated series to be statistically significant. Price adjustments in all co-integrated prices were found to be symmetric.