cssi/SciSciGPT-SciSciNet huggingface dataset:
Investigation of ionospheric electron content variations before earthquakes in southern California, 2003–2004

[1] It has been proposed that earthquakes are preceded by electromagnetic signals detectable from ground- and space-based measurements. Ionospheric anomalies, such as variations in the electron density a few days before earthquakes, are one of the precursory signals proposed. Since Global Positioning System (GPS) data can be used to measure the ionospheric total electron content (TEC), the technique has received attention as a potential tool to detect ionospheric perturbations related to earthquakes. Here, we analyze 2 years (2003–2004) of data from the Southern California Integrated GPS Network (SCIGN), a dense network of 265 continuous GPS stations centered on the Los Angeles basin, for possible precursors. This time period encompasses the December 2003, M6.6, San Simeon and September 2004, M6.0, Parkfield earthquakes. We produce TEC time series at all SCIGN sites and apply three different statistical tests to detect anomalous TEC signals preceding earthquakes. We find anomalous TEC signals but no statistically significant correlation, in time or in space, between these TEC anomalies and the occurrence of earthquakes in southern California for the 2003–2004 period. This result does not disprove the possibility of precursory phenomena but show the signal-to-noise ratio of a hypothetical TEC precursor signature is too low to be detected by the analysis techniques employed here. Precursors may still be revealed for future large earthquakes in well instrumented areas such as California and Japan, if the tests can be developed into techniques that can better separate external influences from the actual TEC signal.
The economics of earnings manipulation and managerial compensation

This article examines managerial compensation in an environment where managers may take a hidden action that affects the actual earnings of the firm. When realized, these earnings constitute hidden information that is privately observed by the manager, who may expend resources to generate an inflated earnings report. We characterize the optimal managerial compensation contract in this setting, and demonstrate that contracts contingent on reported earnings cannot provide managers with the incentive both to maximize profits and to report those profits honestly. As a result, some degree of earnings management must be tolerated as a necessary part of an efficient agreement.
Regulation of orthogonal functions in a dual catalyst system. Subservient role of a nonchiral Lewis acid in an asymmetric catalytic heteroatom Diels-Alder reaction.

A catalytic asymmetric heteroatom Diels-Alder reaction of unactivated imines with Danishefsky’s diene is described which gives high asymmetric induction for N-benzhydryl imines derived from a variety of aldehydes. The catalyst is derived from B(OPh)3 and the VAPOL ligand and gives good induction but the reaction stalls and does not give high conversion (~50%). It was found that in the presence of the both the chiral catalyst and excess amounts of B(OPh)3 the reaction proceeds to completion and gives high yields of the dihydropiperidinone product. Despite the presence of large quantities of the non-chiral Lewis acid B(OPh)3 the asymmetric induction of the product remains constant (90% ee) as the amount of B(OPh)3 is steadily increased and does not drop off until the ratio of B(OPh)3 to VAPOL is 100:1 (82% ee). These observations are interpreted as involving highly separated and different activities for the chiral and non-chiral Lewis acids present in the reaction. Specifically, the excess B(OPh)3 serves to bind to the product and release the chiral catalyst to turnover more starting material. The B(OPh)3 does not compete in turning over of the starting material and a series of binding studies reveals that this likely due to a combination of two factors. The binding studies reveals that the chiral catalyst binds to the starting imine seven times more strongly than does B(OPh)3. However, in order to explain the constant asymmetric induction observed despite the addition of increasing amounts of B(OPh)3 the rate of the reaction of the imine complexed with the chiral catalyst must be at least 10 times faster than the reaction of the imine complexed with B(OPh)3. Finally, a catalyst generated from BINOL and B(OPh)3 does not show this phenomenon.
Program analysis via graph reachability

Abstract This paper describes how a number of program-analysis problems can be solved by transforming them to graph-reachability problems. Some of the program-analysis problems that are amenable to this treatment include program slicing, certain dataflow-analysis problems, one version of the problem of approximating the possible “shapes” that heap-allocated structures in a program can take on, and flow-insensitive points-to analysis. Relationships between graph reachability and other approaches to program analysis are described. Some techniques that go beyond pure graph reachability are also discussed.
Measuring the Predictable Variation in Stock and Bond Returns

Recent studies show that when a regression model is used to forecast stock and bond returns, the sample R [superscript 2] increases dramatically with the length of the return horizon. These studies argue, therefore, that long-horizon returns are highly predictable. This article presents evidence that suggests otherwise. Long-horizon regressions can easily yield large values of the sample R [superscript 2], even if the population R [superscript 2] is small or zero. Moreover, long-horizon regressions with a small or zero population R [superscript 2] can produce t-ratios that might be interpreted as evidence of strong predictability. In general, the analysis provides little support for the view that long-horizon returns are highly predictable. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
Cs-Cs scattering in a juggling fountain

Summary form only given. We juggle atoms in an atomic fountain by launching two balls of laser-cooled Cs atoms in rapid succession. The two balls collide near the top of the fountain trajectory, and we detect the velocity of the scattered atoms, giving information on the differential scattering cross section.
The evolution of genetic architectures underlying quantitative traits

In the classic view introduced by R. A. Fisher, a quantitative trait is encoded by many loci with small, additive effects. Recent advances in quantitative trait loci mapping have begun to elucidate the genetic architectures underlying vast numbers of phenotypes across diverse taxa, producing observations that sometimes contrast with Fisher's blueprint. Despite these considerable empirical efforts to map the genetic determinants of traits, it remains poorly understood how the genetic architecture of a trait should evolve, or how it depends on the selection pressures on the trait. Here, we develop a simple, population-genetic model for the evolution of genetic architectures. Our model predicts that traits under moderate selection should be encoded by many loci with highly variable effects, whereas traits under either weak or strong selection should be encoded by relatively few loci. We compare these theoretical predictions with qualitative trends in the genetics of human traits, and with systematic data on the genetics of gene expression levels in yeast. Our analysis provides an evolutionary explanation for broad empirical patterns in the genetic basis for traits, and it introduces a single framework that unifies the diversity of observed genetic architectures, ranging from Mendelian to Fisherian.
Krylov Subspace Descent for Deep Learning

In this paper, we propose a second order optimization method to learn models where both the dimensionality of the parameter space and the number of training samples is high. In our method, we construct on each iteration a Krylov subspace formed by the gradient and an approximation to the Hessian matrix, and then use a subset of the training data samples to optimize over this subspace. As with the Hessian Free (HF) method of Martens (2010), the Hessian matrix is never explicitly constructed, and is computed using a subset of data. In practice, as in HF, we typically use a positive definite substitute for the Hessian matrix such as the Gauss-Newton matrix. We investigate the effectiveness of our proposed method on deep neural networks, and compare its performance to widely used methods such as stochastic gradient descent, conjugate gradient descent and L-BFGS, and also to HF. Our method leads to faster convergence than either L-BFGS or HF, and generally performs better than either of them in cross-validation accuracy. It is also simpler and more general than HF, as it does not require a positive semidefinite approximation of the Hessian matrix to work well nor the setting of a damping parameter. The chief drawback versus HF is the need for memory to store a basis for the Krylov subspace.
Unequal error protection and progressive decoding for JPEG2000

This paper presents an unequal error protection scheme for still and motion image transmissions. The underlying channel codes are created using a Plotkin construction and offer the novel ability of using one long channel codeword to protect an entire image, yet still allowing progressive decoding. Progressive quality improvements occur in two ways: the first is the usual progressive refinement, where image quality is improved as more data are received; the second is that residual error rates of earlier received data are reduced as more data are received.
Lindblad resonance torques in relativistic discs - II. Computation of resonance strengths

We present a fully relativistic computation of the torques due to Lindblad resonances from perturbers on circular, equatorial orbits on discs around Schwarzschild and Kerr black holes. The computation proceeds by establishing a relation between the Lindblad torques and the gravitational waveforms emitted by the perturber and a test particle in a slightly eccentric orbit at the radius of the Lindblad resonance. We show that our result reduces to the usual formula when taking the non-relativistic limit. Discs around a black hole possess an m = 1 inner Lindblad resonance (ILR) with no Newtonian–Keplerian analogue; however, its strength is very weak even in the moderately relativistic regime (r/M ~ few tens), which is in part due to the partial cancellation of the two leading contributions to the resonant amplitude (the gravitoelectric octupole and gravitomagnetic quadrupole). For equatorial orbits around Kerr black holes, we find that the m = 1 ILR strength is enhanced for retrograde spins and suppressed for prograde spins. We also find that the torque associated with the m ≥ 2 ILRs is enhanced relative to the non-relativistic case; the enhancement is a factor of 2 for the Schwarzschild hole even when the perturber is at a radius of 25M.
Credit markets and patterns of international trade

Abstract Even with identical technology or endowments between countries comparative costs may differ in a world of credit market imperfection. We have explored two kinds of such imperfection, one involving moral hazard considerations in the international credit market under sovereign risk and the other involving differences between countries in their domestic institutions of credit contract enforcement under incomplete information.
Non‐hyperbolic common reflection surface

The method of common reflection surface (CRS) extends conventional stacking of seismic traces over offset to multidimensional stacking over offset-midpoint surfaces. We propose a new form of the stacking surface, derived from the analytical solution for reflection traveltime from a hyperbolic reflector. Both analytical comparisons and numerical tests show that the new approximation can be significantly more accurate than the conventional CRS approximation at large offsets or at large midpoint separations while using essentially the same parameters.
Decomposition and Representation of Coalitional Games

A coalitional game is a real-valued set function ν defined on an algebra F of subsets of a space X such that νO = 0. We prove the existence of a one-to-one correspondence between coalitional games bounded with respect to the composition norm and countably additive measures defined on an appropriate space.
Synthesis of α-ketoamides from a carbamoylsilane and acid chlorides

Treatment of acid chlorides with a carbamoylsilane affords α-ketoamides. In some instances, in situ reaction of additional carbamoylsilane with these products yielded α-organyl-α-siloxymalonamides.
On Ergodicity, Infinite Flow, and Consensus in Random Models

We consider the ergodicity and consensus problem for a discrete-time linear dynamic model driven by random stochastic matrices, which is equivalent to studying these concepts for the product of such matrices. Our focus is on the model where the random matrices have independent but time-variant distribution. We introduce a new phenomenon, the infinite flow, and we study its fundamental properties and relations with the ergodicity and consensus. The central result is the infinite flow theorem establishing the equivalence between the infinite flow and the ergodicity for a class of independent random models, where the matrices in the model have a common steady state in expectation and a feedback property. For such models, this result demonstrates that the expected infinite flow is both necessary and sufficient for the ergodicity. The result is providing a deterministic characterization of the ergodicity, which can be used for studying the consensus and average consensus over random graphs.
History-less checking of dynamic integrity constraints

An efficient implementation method is described for dynamic integrity constraints formulated in past temporal logic. Although the constraints can refer to past states of the database, their checking does not require that the entire database history be stored. Instead, every database state is extended with auxiliary relations that contain the historical information necessary for checking constraints. Auxiliary relations can be implemented as materialized relational views. The author analyzes the computational cost of the method and outlines how it can be implemented by using existing database technology. Related work on dynamic integrity constraints is surveyed. >
A parallel algorithm for incremental stereo matching on SIMD machines

An effort has been made to develop a robust high-speed stereo matcher by exploiting parallel algorithms executing on general-purpose SIMD machines. This approach is based on several existing techniques dealing with the classification and evaluation of matches, the application of ordering constraints, and relaxation-based matching. The techniques have been integrated and reformulated in terms of parallel execution on a theoretical SIMD machine. An ideal machine topology for executing this parallel algorithm is identified through complexity analysis. Feasibility is demonstrated by implementation on a commercially available SIMD machine, and its performance is compared with that of the idealized machine. Sample results are shown for real and synthetic stereo pairs. >
Stereoselective Nucleophilic Trifluoromethylation of N‐(tert‐Butylsulfinyl)imines by Using Trimethyl(trifluoromethyl)silane

A very general reaction is presented to achieve the nucleophilic transfer of "CF3 " to chiral N-(tert-butylsulfinyl)imines in high yield and high stereoselectivity. Tetrabutylammonium difluorotriphenylsilicate (TBAT) functions as a fluoride source, and aromatic, heterocyclic, and aliphatic sulfinylimines react smoothly. The high stereoselectivity suggests that the reaction proceeds through an open transition state. TMS=trimethylsilyl.
Superconducting instability in the periodic Anderson model

Abstract Employing a quantum Monte Carlo simulation we find a pairing instability in the normal state of the infinite dimensional periodic Anderson model. Superconductivity arises from a normal state in which the screening is protracted and which is clearly not a Fermi liquid. The phase diagram is re-entrant reflecting competition between superconductivity and Fermi liquid formation. The estimated superconducting order parameter is even, but has nodes as a function of frequency. This opens the possibility of a temporal node and an effective order parameter composed of charge pairs and spin excitations.
On the Maximum Quadratic Assignment Problem

Quadratic assignment is a basic problem in combinatorial optimization that generalizes several other problems such as traveling salesman, linear arrangement, dense k subgraph, and clustering with given sizes. The input to the quadratic assignment problem consists of two n × n symmetric nonnegative matrices $W=(w_{i, j})$ and $D=(d_{i, j})$ . Given matrices W, D, and a permutation $\pi: [n] \rightarrow [n]$ , the objective function is $Q(\pi):= \sum_{i, j \in [n], i \ne j} w_{i, j} \cdot d_{\pi(i), \pi(j)}$ . In this paper, we study the maximum quadratic assignment problem, where the goal is to find a permutation π that maximizes $Q(\pi)$ . We give an $\tilde{O}(\sqrt{n})$ -approximation algorithm, which is the first nontrivial approximation guarantee for this problem. The above guarantee also holds when the matrices W, D are asymmetric. An indication of the hardness of maximum quadratic assignment is that it contains as a special case the dense k subgraph problem, for which the best-known approximation ratio is $\approx n^{1/3}$ (Feige et al. [Feige, U., G. Kortsarz, D. Peleg. 2001. The dense k-subgraph problem. Algorithmica29(3) 410--421]). When one of the matrices W, D satisfies triangle inequality, we obtain a $2e/(e-1) \approx 3.16$ -approximation algorithm. This improves over the previously best-known approximation guarantee of four (Arkin et al. [Arkin, E. M., R. Hassin, M. Sviridenko. 2001. Approximating the maximum quadratic assignment problem. Inform. Processing Lett.77 13--16]) for this special case of maximum quadratic assignment. The performance guarantee for maximum quadratic assignment with triangle inequality can be proved relative to an optimal solution of a natural linear programming relaxation that has been used earlier in branch-and-bound approaches (see, eg., Adams and Johnson [Adams, W. P., T. A. Johnson. 1994. Improved linear programming-based lower bounds for the quadratic assignment problem. DIMACS Ser. Discrete Math. Theoret. Comput. Sci.16 43--77]). It can also be shown that this linear program (LP) has an integrality gap of $\tilde{\Omega}(\sqrt{n})$ for general maximum quadratic assignment.
State change architecture: a protocol for executable process models

The key concepts and requirements for a process mechanism and the state change architecture (SCA) protocols are presented. The SCA is thought to solve many of the process modeling problems associated with conventional languages and methods. It integrates object-oriented programming, a common repository for the logical view of data, and logic programming. >
Dynamic scheduling of modern-robust-control autopilot designs for missiles

The dynamic scheduling of multiple linear-time-invariant (LTI) controllers, designed using H/sub infinity // mu techniques, for systems with widely varying plant dynamics is examined. The observer/full-state feedback structure of the LTI H/sub infinity / controller is extended to accommodate the time-varying, nonlinear dynamics problem. A procedure for handling the variations that occur between fixed operating points, in the two-Riccati equation solutions, is proposed. An example missile control problem that contains realistic and necessary performance goals and robustness constraints is included to demonstrate the viability of the approach. >
Hybrid quantum nanophotonic devices for coupling to rare-earth ions

With an assortment of narrow line-width transitions spanning the visible and IR spectrum and long spin coherence times, rare-earth doped crystals are the leading material system for solid-state quantum memories. Integrating these materials in an on-chip optical platform would create opportunities for highly integrated light-matter interfaces for quantum communication and quantum computing. Nano-photonic resonators with high quality factors and small mode volumes are required for efficient on-chip coupling to the small dipole moment of rare-earth ion transitions. However, direct fabrication of optical cavities in these crystals with current nanofabrication techniques is difficult and unparallelized, as either exotic etch chemistries or physical milling processes are required. We fabricated hybrid devices by mechanically transferring a nanoscale membrane of gallium arsenide (GaAs) onto a neodymium-doped yttrium silicon oxide (Y2SiO5) crystal and then using electron beam lithography and standard III-V dry etching to pattern nanobeam photonic crystal cavities and ring resonator cavities, a technique that is easily adapted to other frequency ranges for arbitrary dopants in any rare earth host system. Single crystalline GaAs was chosen for its low loss and high refractive index at the transition wavelength. We demonstrated the potential to evanescently couple between the cavity field and the 883 nm 4I9/2- 4F3/2 transition of nearby neodymium impurities in the host crystal by examining transmission spectra through a waveguide coupled to the resonator with a custom-built confocal microscope. The prospects and requirements for using this system for scalable quantum networks are discussed.
Agent-oriented programming

Shoham, Y., Agent-oriented programming, Artificial Intelligence 60 (1993) 51-92. A new computational framework is presented, called agent-oriented programming (AOP), which can be viewed as a specialization of object-oriented programming. The state of an agent consists of components such as beliefs, decisions, capabilities, and obligations; for this reason the state of an agent is called its mental state. The mental state of agents is described formally in an extension of standard epistemic logics: beside temporalizing the knowledge and belief operators, AOP introduces operators for obligation, decision, and capability. Agents are controlled by agent programs, which include primitives for communicating with other agents. In the spirit of speech act theory, each communication primitive is of a certain type: informing, requesting, offering, and so on. This article presents the concept of AOP, discusses the concept of mental state and its formal underpinning, defines a class of agent interpreters, and then describes in detail a specific interpreter that has been implemented.
Hedge Funds: Risk and Return

From a database that is relatively free of bias, this article provides measures of the returns of hedge funds and of the distinctly nonnormal characteristics of the data. The results include risk-adjusted measures of performance and tests of the degree to which hedge funds live up to their claim of market neutrality. The substantial attrition of hedge funds is examined, the determinants of hedge fund demise are analyzed, and results of tests of return persistence are presented. The conclusion is that hedge funds are riskier and provide lower returns than is commonly supposed.
Evaluation of a thin-slot formalism for finite-difference time-domain electromagnetics codes

A thin-slot formalism proposed by Gilbert and Holland (1981) for use with finite-difference time-domain (FDTD) electromagnetics codes has been evaluated in both two and three dimensions. This formalism allows narrow slots to be modeled in the wall of a scatterer without reducing the spatial grid size to the slot width. In two dimensions, the evaluation involves the calculation of the total fields near two infinitesimally thin coplanar strips separated by a gap. A method-of-moments (MoM) solution of the same problem serves as a benchmark for comparison. Results in two dimensions show that up to 10 percent error can be expected in total electric and magnetic fields both near ( lambda /40) and far (1 lambda ) from the gap. In three dimensions, the evaluation is similar. The finite-length slot is placed in a finite plate and an MoM surface patch solution is used for the benchmark. These data show that slightly larger errors can be expected. >
Water Conservation in Irrigated Agriculture: Trends and Challenges in the Face of Emerging Demands

This report relies on findings from several national surveys and current literature to assess water resource use and conservation measures within the U.S. irrigated crop sector. U.S. agriculture accounts for 80-90 percent of the Nation’s consumptive water use (water lost to the environment by evaporation, crop transpiration, or incorporation into products). Expanding water demands to support population and economic growth, environmental flows (water within wetlands, rivers, and groundwater systems needed to maintain natural ecosystems), and energy-sector growth, combined with Native American water-right claims and supply/demand shifts expected with climate change, will present new challenges for agricultural water use and conservation, particularly for the 17 Western States that account for nearly three-quarters of U.S. irrigated agriculture. Despite technological innovations, at least half of U.S. irrigated cropland acreage is still irrigated with less efficient, traditional irrigation application systems. Sustainability of irrigated agriculture will depend partly on whether producers adopt more efficient irrigation production systems that integrate improved on farm water management practices with efficient irrigation application systems.
Selling and Leasing Strategies for Durable Goods with Complementary Products

It has been recognized that when a durable goods manufacturer sells its output, it has an incentive to produce at a rate that will drive down the market price of the product over time. Because anticipation of declining prices makes consumers less willing to invest in owning the durable good, selling can be self-defeating for the manufacturer. If the manufacturer instead leases the product, it can eliminate its own incentive to decrease the price over time, which allows it to extract larger rents from consumers. In this paper, we investigate how a durable goods manufacturer's choice between leasing and selling is affected by a complementary product that is produced by an independent firm. We show that a durable goods manufacturer that leases its product has an incentive to increase prices (by limiting the availability of the product) in response to the availability of a complement. Because this potential for opportunistic behavior discourages output of the complement, leasing can also be problematic. As a result, the durable goods manufacturer faces a trade-off between leasing, which commits the manufacturer to not overproduce, and selling, which commits it to not underproduce. Our contribution is to identify this trade-off and show how a durable goods manufacturer can use a combination of leasing and selling to balance its strategic commitment across both its own market as well as the complementary market.
Quantification of liquid refrigerant distribution in parallel flow microchannel heat exchanger using infrared thermography

Abstract This paper presents a method to quantify the distribution of liquid refrigerant mass flow rate in a parallel flow microchannel heat exchanger from the infrared images. Quantification is achieved by building the relationship between the liquid mass flow rate through each microchannel tube and the air-side capacity calculated from the infrared measurement of the wall temperature. After being implemented in a heat exchanger model, the quantification method is validated against experimental data. This method can be used for several types of heat exchangers: evaporators, condensers, gas-coolers, etc., also it can be applied to various heat exchanger designs: different inlet/outlet locations, different flow configurations, etc.
Synthesis of application-specific memory designs

This paper discusses the mapping of arrays in a behavior to memories in an implementation. We introduce a novel approach to the design of memory systems, which is based on a variety of array grouping techniques and dimensional transformations, and the binding of array groups to memory components with different dimensions, access times, and number of ports. The results of design actions are computed in terms of memory cost, the number of wires necessary to connect the memory to the data path, and the limit of performance imposed by the memory design on the implementation. Three different procedures can be used to find a suitable memory design. All three procedures are directed by a weighted and constrained system cost function, which enables the expression of the user's design priorities. Compared to related research efforts, our approach improves performance by as much as 19%, reduces memory cost as 40%, and decreases the number of wires required to connect the memory to the data path by up to 57%.
Cyclizations of 2-alkylthiazolines and 2-alkyloxazolines with α,α-disubstituted diacid chlorides or N-(chlorocarbonyl) isocyanate

Abstract Two-step cyclizations of 2-alkylthiazolines or 2-alkyloxazolines with α,α-disubstituted diacid chlorides produce excellent yields of 6,6-dialkyl-2,3-dihydrothiazolo[3,2- a ]pyridine-5,7-diones and 6,6-dialkyl-2,3-dihydrooxazolo[3,2- a ]pyridine-5,7-diones in refluxing acetonitrile containing Et 3 N. Similar cyclizations using N -(chlorocarbonyl) isocyanate in place of diacid chlorides produced 2,3-dihydrothiazolo[3,2- c ]pyrimidine-5,7-diones or 2,3-dihydrooxazolo[3,2- c ]pyrimidine-5,7-diones, respectively. Each cyclization proceeded through cyclic ketene-N,X-acetal (X = O or S) intermediates.
Time-Space Lower Bounds for the Polynomial-Time Hierarchy on Randomized Machines

We establish the first polynomial-strength time-space lower bounds for problems in the linear-time hierarchy on randomized machines with two-sided error. We show that for any integer $\ell > 1$ and constant $c < \ell$, there exists a positive constant $d$ such that QSAT$_{\ell}$ cannot be computed by such machines in time $n^c$ and space $n^d$, where QSAT$_{\ell}$ denotes the problem of deciding the validity of a quantified Boolean formula with at most $\ell - 1$ quantifier alternations. Moreover, $d$ approaches 1/2 from below as $c$ approaches 1 from above for $\ell = 2$, and $d$ approaches 1 from below as $c$ approaches 1 from above for $\ell \ge 3$. In fact, we establish the stronger result that for any constants $a \le 1$ and $c < 1 + (\ell - 1)a$, there exists a positive constant $d$ such that linear-time alternating machines using space $n^a$ and $\ell - 1$ alternations cannot be simulated by randomized machines with two-sided error running in time $n^c$ and space $n^d$, where $d$ approaches $a/2$ from below as $c$ approaches 1 from above for $\ell = 2$, and $d$ approaches $a$ from below as $c$ approaches 1 from above for $\ell \ge 3$. Corresponding to $\ell = 1$, we prove that there exists a positive constant $d$ such that the set of Boolean tautologies cannot be decided by a randomized machine with one-sided error in time $n^{1.759}$ and space $n^d$. As a corollary, this gives the same lower bound for satisfiability on deterministic machines, improving on the previously best known such result.
Characterization of electronic structure of periodically strained graphene

We induced periodic biaxial tensile strain in polycrystalline graphene by wrapping it over a substrate with repeating pillar-like structures with a periodicity of 600 nm. Using Raman spectroscopy, we determined to have introduced biaxial strains in graphene in the range of 0.4% to 0.7%. Its band structure was characterized using photoemission from valance bands, shifts in the secondary electron emission, and x-ray absorption from the carbon 1s levels to the unoccupied graphene conduction bands. It was observed that relative to unstrained graphene, strained graphene had a higher work function and higher density of states in the valence and conduction bands. We measured the conductivity of the strained and unstrained graphene in response to a gate voltage and correlated the changes in their behavior to the changes in the electronic structure. From these sets of data, we propose a simple band diagram representing graphene with periodic biaxial strain.
Thermomechanical design of normal-conducting deflecting cavities at the advanced photon source for short x-ray pulse generation

A normal-conducting deflecting cavity is being designed at the Advanced Photon Source (APS) as a part of the short x-ray pulse project intended to provide users with approximately 2 picosecond x-rays. The system will use two pairs of 3-cell cavities in sectors 6ID and 7ID for the generation of the x-ray pulse in the 7ID beamline. The 3-cell cavities are designed to provide the desired beam deflection while absorbing in excess of 4 kW of power from a pulsed rf system and up to 2.6 kW in the damper system of high-order mode (HOM) and low-order mode (LOM) waveguides. Since the cavity frequency is very sensitive to thermal expansion, the cooling water system is designed so that it is able to control cavity temperature to within 0.1degC. This paper describes the optimization of the thermomechanical design of the cavity based on calculation of thermal stresses and displacement caused by the generated heat loads, and presents the design of a cooling water system required for the proper operation of the cavities.
Synthesis and X-ray crystal structures of the first antimony and bismuth calixarene complexes

The reaction of the monosodium salt of p-tert-butylcalix[4]arene (ButC4) with 2 equivalents of SbCl3 provides ButC4(SbCl)2 and the first bismuth calixarene complex was prepared by treatment of p-tert-butylcalix[8]arene (ButC8) with Bi[N(SiMe3)2]3 in toluene.
Knowledge-Based Hierarchies: Using Organizations to Understand the Economy

Incorporating the decision of how to organize the acquisition, use, and communication of knowledge into economic models is essential to understand a wide variety of economic phenomena. We survey the literature that has used knowledge-based hierarchies to study issues such as the evolution of wage inequality, the growth and productivity of firms, economic development, and the gains from international trade, as well as offshoring and the formation of international production teams. We also review the nascent empirical literature that has, so far, confirmed the importance of organizational decisions and many of their more salient implications.
The geometry of sampling on unions of lattices

In this paper we show two results concerning sampling translation-invariant subspaces of L 2 (R d ) on unions of lattices. The first result shows that the sampling transform on a union of lattices is a constant times an isometry if and only if the sampling transform on each individual lattice is so. The second result demonstrates that the sampling transforms of two unions of lattices on two bands have orthogonal ranges if and only if, correspondingly, the sampling transforms of each pair of lattices have orthogonal ranges. We then consider sampling on shifted lattices.
Halo- and Azidodediazoniation of Arenediazonium Tetrafluoroborates with Trimethylsilyl Halides and Trimethylsilyl Azide and Sandmeyer-Type Bromodediazoniation with Cu(I)Br in [BMIM][PF6] Ionic Liquid§

Reaction of [ArN2][BF4] salts immobilized in [BMIM][PF6] ionic liquid (IL) with TMSX (X = I, Br) and TMSN3 represents an efficient method for the preparation of iodo-, bromo-, and azido-derivatives via dediazoniation. The reactions can also be effected starting with ArNH2 by in situ diazotization with [NO][BF4] followed by reaction with TMSX or TMSN3. Depending on the substituents on the benzenediazonium cation, competing fluorodediazoniation (ArF formation) and hydrodediazoniation (ArH formation) were observed. Dediazoniation with TMSN3 and with TMSI generally gave the highest chemoselectivity toward ArN3 and ArI formation. The IL was recycled and reused up to 5 times with no appreciable decrease in the conversions. Multinuclear NMR monitoring of the interaction of [ArN2][BF4]/TMSX, [BMIM][PF6]/TMSX, and [BMIM][PF6]/TMSX/[ArN2][BF4] indicated that TMSF is formed primarily via [ArN2][BF4]/TMSX, generating [ArN2][X] in situ, which gives ArX on dediazoniation. Competing formation of ArF in Sandmeyer-type br...
Local detection of occlusion boundaries in video

Occlusion boundaries are notoriously difficult for many patch-based computer vision algorithms, but they also provide potentially useful information about scene structure and shape. Using short video clips, we present a novel method for scoring the degree to which occlusion is visible at detected edges. We first utilise a spatio-temporal edge detector which estimates edge strength, orientation, and normal motion. By then extracting patches from either side of each detected (possibly moving) edge pixel, we can estimate and compare motion to determine if occlusion is present. In experiments on synthetic and natural images, we demonstrate our ability to differentiate occlusion boundary pixels from simple edge pixels by using motion information. In terms of precision versus recall, our occlusion scoring metric outperforms a rank-based motion inconsistency measure from the literature. The completely local, bottom-up approach described here is intended to provide powerful low-level information for use by higher-level reasoning methods.
On a class of Banyan networks and tandem Banyan switching fabrics

This paper examines the operating characteristics of a class of tandem Banyan switching fabrics (TBSF's) built using bi-delta networks. We use the functional equivalence between bi-delta networks to induce an equivalence between TBSF's. A weaker form of equivalence guaranteeing identical performance under conditions of symmetric traffic is studied, and a sufficient condition for weak equivalence between functionally distinct TBSF's is established. These results hold for a variety of conflict resolution policies (CRP's) in addition to the one studied by Tobagi et al. (see IEEE J. Select. Areas Commun., vol.9, p.1173, 1991). Simulations indicate that a TBSF constructed by cascading omega networks, (or in fact any other TBSF in its weak equivalence class), performs better than the two TBSF's studied by Tobagi et al., and converges rapidly to a theoretical lower bound on the loss rate, in the region of interest. It is also shown that this loss rate is almost independent of the size of such a TBSF in the region of interest. >
From growth to green growth -- a framework

Green growth is about making growth processes resource-efficient, cleaner and more resilient without necessarily slowing them. This paper aims at clarifying these concepts in an analytical framework and at proposing foundations for green growth. The green growth approach proposed here is based on (1) focusing on what needs to happen over the next 5-10 years before the world gets locked into patterns that would be prohibitively expensive and complex to modify and (2) reconciling the short and the long term, by offsetting short-term costs and maximizing synergies and economic co-benefits. This, in turn, increases the social and political acceptability of environmental policies. This framework identifies channels through which green policies can potentially contribute to economic growth. However, only detailed country- and context-specific analyses for each of these channels could reach firm conclusion regarding their actual impact on growth. Finally, the paper discusses the policies that can be implemented to capture these co-benefits and environmental benefits. Since green growth policies pursue a variety of goals, they are best served by a combination of instruments: price-based policies are important but are only one component in a policy tool-box that can also include norms and regulation, public production and direct investment, information creation and dissemination, education and moral suasion, or industrial and innovation policies.
A Butterfly in the Making: Revealing the Near-Infrared Structure of Hubble 12

We present deep narrowband near-IR images and moderate resolution spectra of the young planetary nebula Hubble 12. These data are the first to show clearly the complex structure for this important planetary nebula. Images were obtained at lambda = 2.12, 2.16, and 2.26 micron. The lambda = 2.12 Am image reveals the bipolar nature of the nebula, as well as complex structure near the central star in the equatorial region. The images show an elliptical region of emission, which may indicate a ring or a cylindrical source structure. This structure is possibly related to the mechanism that is producing the bipolar flow. The spectra show the nature of several distinct components. The central object is dominated by recombination lines of H I and He I. The core is not a significant source of molecular hydrogen emission. The east position in the equatorial region is rich in lines of ultraviolet-excited fluorescent H2. A spectrum of part of the central region shows strong [Fe II] emission, which might indicate the presence of shocks.
Combustion Synthesis of Silicon Nitride‐Silicon Carbide Composites

The feasibility of synthesizing silicon nitride-silicon carbide composites by self-propagating high-temperature reactions is demonstrated. Various mixtures of silicon, silicon nitride, and carbon powders were ignited under a nitrogen pressure of 30 atm (∼ 3 MPa), to produce a wide composition range of Si3N4-SiC powder products. Products containing up to 17 vol% of SiC, after being attrition milled, could be hot-pressed to full density under 1700°C, 3000 psi (∼ 21 MPa) with 4 wt% of Y2O3. The microhardness and fracture toughness of these composites were superior to those of the pure β-Si3N4 matrix material and compared very well with the properties of “traditionally” prepared composites.
Using PSpice to determine the relative stability of RC active filters

Abstract A simple procedure for using PSpice to calculate the relative stability of an active circuit as described. The active circuit can be implemented using a variety of active devices, including op.-amps, current conveyors, transimpedance amplifiers or operational transconductance amplifiers. The procedure can be used with the PSpice macromodels provided by amplifier manufacturers.
Multi-user privacy: The Gray-Wyner system and generalized common information

The problem of preserving privacy when a multi-variate source is required to be revealed partially to multiple users is modeled as a Gray-Wyner source coding problem with K correlated sources at the encoder and K decoders in which the kth decoder, k = 1, 2, …, K, losslessly reconstructs the kth source via a common link of rate R 0 and a private link of rate R k . The privacy requirement of keeping each decoder oblivious of all sources other than the one intended for it is introduced via an equivocation constraint E k at decoder k such that the total equivocation summed over all decoders E ≥ Δ. The set of achievable ({R k }K k=1 ,R 0 ,Δ) rates-equivocation (K + 2)-tuples is completely characterized. Using this characterization, two different definitions of common information are presented and are shown to be equivalent.
Resource management and QoS control in multiple traffic wireless and mobile Internet systems

End-to-end quality of service (QoS) control for multiple traffic in wired networks is carried out through Differentiated services (DiffServ). Edge routers in DiffServ domain classify incoming flows into different per-hop behavior (PHB) groups and give a policy-based QoS guarantee to these behavior aggregates. As Internet extends into the wireless and mobile section, different traffic flows should be treated differently not only in wired core network, but also in wireless resource allocations. In this paper, we propose a preemptive priority handoff and adaptive resource allocation scheme. DiffServ PHB groups are mapped into different wireless and mobile QoS classes. Traffic flows are categorized into these classes in order to allow the system to allocate different bandwidth and make resource reservation according to their priorities. Higher priority traffic flows are permitted to preempt lower priority flows in service. Lower ones, on the contrary, can expand their bandwidth into areas reserved for higher priority traffic flows for better resource utilization. We use both analytical model and simulation to evaluate the system performance in terms of blocking probabilities, forced termination probabilities, and delay. The forced termination probability of high priority traffic flows can be decreased significantly by introducing the preemptive priority scheme. Therefore, this scheme can be used in wireless part of the system along with DiffServ to give further guarantee for low delay, low jitter, and low loss services to high priority services. Copyright © 2005 John Wiley & Sons, Ltd.
Stereoselective synthesis of hex-2-(E)-en-4-yn-1,6-dioates and E,Z-muconic acid diesters via organo-catalyzed self-coupling of propiolates

Alkyl propiolate couples with itself in the presence of catalytic DABCO under very mild conditions to provide a quantitative yield of E-hex-2-en-4-yne dioates. Hydrogenation of these enyne dioates using Lindlar catalyst provides the corresponding E,Z-diene dioate, a common structural motif found in an array of natural products.
Controlling a submerged rigid body: A geometric analysis

In this paper we analyze the equations of motion of a submerged rigid body. Our motivation is based on recent developments done in trajectory design for this problem. Our goal is to relate some properties of singular extremals to the existence of decoupling vector fields. The ideas displayed in this paper can be viewed as a starting point to a geometric formulation of the trajectory design problem for mechanical systems with potential and external forces.
System Synthesis for Networks of Programmable Blocks

The advent of sensor networks presents untapped opportunities for synthesis. We examine the problem of synthesis of behavioral specifications into networks of programmable sensor blocks. The particular behavioral specification we consider is an intuitive user-created network diagram of sensor blocks, each block having a pre-defined combinational or sequential behavior. We synthesize this specification to a new network that utilizes a minimum number of programmable blocks in place of the pre-defined blocks, thus reducing network size and hence network cost and power. We focus on the main task of this synthesis problem, namely partitioning pre-defined blocks onto a minimum number of programmable blocks, introducing the efficient but effective PareDown decomposition algorithm for the task. We describe the synthesis and simulation tools we developed. We provide results showing excellent network size reductions through such synthesis, and significant speedups of our algorithm over exhaustive search while obtaining near-optimal results for 15 real network designs as well as nearly 10,000 randomly generated designs.
The Entropy Power Inequality and Mrs. Gerber's Lemma for Groups of Order ${2^{n}}$

Shannon's entropy power inequality can be viewed as characterizing the minimum differential entropy achievable by the sum of two independent random variables with fixed differential entropies. The entropy power inequality has played a key role in resolving a number of problems in information theory. It is therefore interesting to examine the existence of a similar inequality for discrete random variables. In this paper, we obtain an entropy power inequality for random variables taking values in a group of order $2^{n}$ , i.e., for such a group $G$ , we explicitly characterize the function $f_{G}(x,y)$ giving the minimum entropy of the sum of two independent $G$ -valued random variables with respective entropies $x$ and $y$ . Random variables achieving the extremum in this inequality are thus the analogs of Gaussians in this case, and these are also determined. It turns out that $f_{G}(x,y)$ is convex in $x$ for fixed $y$ and, by symmetry, convex in $y$ for fixed $x$ . This is a generalization to groups of order $2^{n}$ of the result known as Mrs. Gerber's Lemma.