cssi/SciSciGPT-SciSciNet huggingface dataset:
Synthetic stitching with silicon: Geminal alkylation-hydroxylation of alkynyl carbonyl compounds

A new strategy for the synthesis of β-carbonyl-substituted tertiary alcohols from α,β-alkynyl ketones and esters has been demonstrated. A silicon tether is used to internally deliver an alkyl group, which, combined with a C−Si to C−O transformation, can regio- and diastereoselectively “stitch” together geminal C−C and C−O bonds at the β-position of an electron-withdrawing group. Regioselective alkyne hydrosilylation by a trans addition process provides clean access to trisubstituted vinylsilanes. Subsequent one-pot fluoride-induced C−C bond formation and oxidation of the resulting tertiary silane, a type of silane not normally reactive to such conditions, affords the desired products. The utility of neighboring ketone and carboxylate groups in promoting the oxidation of these highly hindered tertiary alcohols, an observation that may affect synthetic design of routes depending on such oxidations, is demonstrated. Good diastereoselection (>10:1) is observed for substrates bearing γ-alkoxy stereocenters.
Chandra X-ray observation of a mature cloud-shock interaction in the bright eastern knot region of puppis a

We present Chandra X-ray images and spectra of the most prominent cloud-shock interaction region in the Puppis A supernova remnant. The Bright Eastern Knot (BEK) has two main morphological components: (1) a bright compact knot that lies directly behind the apex of an indentation in the eastern X-ray boundary and (2) lying 1 westward behind the shock, a curved vertical structure (bar) that is separated from a smaller bright cloud (cap) by faint diffuse emission. Based on hardness images and spectra, we identify the bar and cap as a single shocked interstellar cloud. Its morphology strongly resembles the "voided sphere" structures seen at late times in Klein et al. experimental simulat.ions of cloud-shock interactions, when the crushing of the cloud by shear instabilities is well underway. We infer an intera.ction time of roughly cloud-crushing timescales, which translates to 2000-4000 years, based on the X-ray temperature, physical size, and estimated expansion of the shocked cloud. This is the first X-ray identified example of a cloud-shock interaction in this advanced phase. Closer t o the shock front, the X-ray emission of the compact knot in the eastern part of the BEK region implies a recent interaction with relatively denser gas, some of which lies in front of the remnant. The complex spatial relationship of the X-ray emission of the compact knot to optical [O III] emission suggests that there are multiple cloud interactions occurring along the line of sight.
A History of Chinese Civilization

Written with an elegant and flowing narrative, the essential virtue of Jacques Gernet's classic book is to see the history of Chinese civilization as a whole. Yet within the synthesis of the trends - social, political, religious, scientific, artistic that make up China's past and present, the author never loses sight of the telling detail which brings history to life. A History of Chinese Civilization is illustrated with a wide range of photographs, many maps, line drawings and tables. A detailed chronological table and full bibliography complement the text.
Structure and Thermoelectric Properties of the New Quaternary Bismuth Selenides A1−xM4−xBi11+xSe21 (A=K and Rb and Cs; M=Sn and Pb)—Members of the Grand Homologous Series Km(M6Se8)m(M5+nSe9+n)

Several members of the new family A1−xM4−xBi11+xSe21 (A=K, Rb, Cs; M=Sn, Pb) were prepared by direct combination of A2Se, Bi2Se3, Sn (or Pb), and Se at 800 °C. The single-crystal structures of K0.54Sn3.54Bi11.46Se21, K1.46Pb3.08Bi11.46Se21, Rb0.69Pb3.69Bi11.31Se21, and Cs0.65Pb3.65Bi11.35Se21 were determined. The compounds A1−xM4−xBi11+xSe21 crystallize in a new structure type with the monoclinic space group C2/m, in which building units of the Bi2Te3 and NaCl structure type join to give rise to a novel kind of three-dimensional anionic framework with alkali-ion-filled tunnels. The building units are assembled from distorted, edge-sharing (Bi,Sn)Se6 octahedra. Bi and Sn/Pb atoms are disordered over the metal sites of the chalcogenide network, while the alkali site is not fully occupied. A grand homologous series Km(M6Se8)m(M5+nSe9+n) has been identified of which the compounds A1−xM4−xBi11+xSe21 are members. We discuss here the crystal structure, charge-transport properties, and very low thermal conductivity of A1−xM4−xBi11+xSe21.
NUCLEAR MAGNETIC RELAXATION IN POLYACETYLENE

Abstract : Nuclear spin-lattice relaxation rates for 1H and 13C in polyacetylene cannot be adequately explained in terms of either nuclear spin diffusion to a static paramagnetic defect or rapid one-dimensional diffusion of the defect itself. We propose a model in which only a small fraction of the molecular chains contain defects. Nuclei on these chains are rapidly relaxed, while the remainder achieve equilibrium by nuclear spin diffusion. The dependences of the measured relaxation rates upon frequency and isotopic concentration are in agreement with the predictions of this model.
Ion-implantation-induced phase separation and crystallization in lithia-silica glasses☆

Abstract Crystallization of annealed Li2O · 2 SiO2 glasses implanted with inert ions and fused SiO2 glass implanted with Li ions was monitored using infrared reflection spectroscopy. Elastic recoil detection analysis was used to study changes in the Li and H concentration induced in these glasses by implantation and annealing. Implantation of Li2O · 2 SiO2 with inert ions results in Li depletion, accompanied by H indiffusion, in the implanted region. For Li-implanted SiO2, crystallization of α-quartz is accompanied by appreciable Li diffusion to the surface and attendant H migration to the Li-depleted region. The crystallization mechanisms are discussed in terms of separation in the lithia-silica system.
Unmasking the Supernova Impostors

The canonical picture of a supernova impostor is a short (~months) –11 MV –14 optical transient from a massive (M * 40 M ☉) star during which the star ejects a dense shell of material. Dust formed in the ejecta then obscures the star. In this picture, the geometric expansion of the shell leads to clear predictions for the evolution of the optical depths and hence the evolution of the optical through mid-IR emissions. Here, we review the theory of this standard model and then examine the impostors SN 1954J, SN 1997bs, SN 1999bw, SN 2000ch, SN 2001ac, SN 2002bu, SN 2002kg, and SN 2003gm, as well as the potential archetype η Carinae. SN 1999bw, SN 2000ch, SN 2001ac, SN 2002bu, and SN 2003gm all show mid-IR emission indicative of dust, and the luminosities of SN 1999bw, SN 2001ac, SN 2002bu, and SN 2003gm are dominated by dust emission. We find only upper limits on dust emission from SN 1954J, SN 1997bs, and SN 2002kg. The properties of these sources are, however, broadly inconsistent with the predictions of the canonical model. Based on their mid-IR properties, there are at least three classes of objects being labeled as "impostors." The first class, containing the luminous blue variable (LBV) SN 2002kg and the non-LBV SN 2000ch, consists of variable stars with little or no dust formation as a consequence of the transient. The second class contains the "classical" impostors SN 1954J, SN 1997bs, and (maybe) SN 2003gm that may be weaker analogs of η Carinae. However, if these sources are stellar eruptions, the visual transient is simply a signal that the star is entering a phase with high mass-loss rates and dust formation that must last far longer than the observed optical transient. The third class consists of the SN 2008S-like transients, SN 1999bw, SN 2001ac, SN 2002bu, and (maybe) SN 2003gm, which are obscured by dust re-forming in a pre-existing wind after it was destroyed by an explosive transient. For all three classes of source, there are no cases where a detected source at late times is significantly fainter than the progenitor star. They are also all transients of relatively low-mass (M * 25 M ☉) stars, rather than high-mass (M * 40 M ☉) stars radiating near the Eddington limit like η Carinae. The durations and energetics of these transients cannot be properly characterized without near/mid-IR observations, and the fragmentary nature of the available data leads to considerable uncertainties in our understanding of the individual sources. Continued monitoring of the sources at both optical and near/mid-IR wavelengths should resolve these ambiguities.
The Mind as Neural Software? Understanding Functionalism, Computationalism, and Computational Functionalism

Defending or attacking either functionalism or computationalism requires clarity on what they amount to and what evidence counts for or against them. My goal here is not to evaluate their plausibility. My goal is to formulate them and their relationship clearly enough that we can determine which type of evidence is relevant to them. I aim to dispel some sources of confusion that surround functionalism and computationalism, recruit recent philosophical work on mechanisms and computation to shed light on them, and clarify how functionalism and computationalism may or may not legitimately come together.
Balancing repair and tolerance of DNA damage caused by alkylating agents

Alkylating agents constitute a major class of frontline chemotherapeutic drugs that inflict cytotoxic DNA damage as their main mode of action, in addition to collateral mutagenic damage. Numerous cellular pathways, including direct DNA damage reversal, base excision repair (BER) and mismatch repair (MMR), respond to alkylation damage to defend against alkylation-induced cell death or mutation. However, maintaining a proper balance of activity both within and between these pathways is crucial for a favourable response of an organism to alkylating agents. Furthermore, the response of an individual to alkylating agents can vary considerably from tissue to tissue and from person to person, pointing to genetic and epigenetic mechanisms that modulate alkylating agent toxicity.
The central starburst and ionization mechanism in the liner/H II region transition nucleus in NGC 4569

We present a comprehensive study to determine whether the LINER/H II region transition spectrum in NGC 4569 can be generated solely by photoionization by the nuclear starburst. A review of the multiwavelength data from the literature reveals no additional sources that contribute to the ionization. We find that the young starburst dominating the UV emission is distinct from the nuclear population of A supergiants identified in the optical spectrum by W. Keel. Spectral synthesis analysis provides constraints on the physical nature of the starburst, revealing a 5–6 Myr, approximately instantaneous starburst with subsolar metallicity. These results are used to model the spectral energy distribution of the ionizing continuum. Luminosity constraints place limits on the steepness of the extinction curve for the young starburst. The Savage & Mathis curve satisfies all luminosity constraints and the derived reddening is similar to the emission-line reddening. These results imply extreme conditions in the nuclear starburst, with ~5 × 104 O and B stars compacted in the inner 9'' × 13'' region of the nucleus. Using photoionization analysis and employing all observational constraints on the emission-line gas, we find very specific conditions are required if the spectrum is generated solely by stellar photoionization. At least two spatially distinct components are required: a compact region with strong O III emission and an extended, low-density component emitting most of the S II flux. A high-density component is also needed to generate the O I flux. Additionally, a limited contribution from Wolf-Rayet stars to the ionizing SED is necessary, consistent with the results of a study by A. Barth and J. Shields. We present a physical interpretation for the multicomponent emission-line gas.
Combustion Roar as Observed in Industrial Furnaces

Factory noise in recent years has become a source of increasing attention, both because of the action of regulatory bodies and because of increased industrial awareness of possible detrimental effects to workers. This paper concerns one significant source of factory noise, namely, combustion roar. Combustion roar accompanies any turbulent flame, premixed or diffusion. Generally, it increases with the rate and intensity of combustion. The effects of several variables, such as firing rate, turbulence intensity, and burner type, on the noise output of flames in an acoustically-infinite situation are first considered. Then, the available information on the changes in the acoustic performance of burners when they are placed in furnaces is discussed. Finally, some remarks are made concerning the suppression of combustion roar.
Perceived egocentric distances in real, image-based, and traditional virtual environments

In virtual environments, perceived egocentric distances are consistently underestimated when compared to the same distance judgments in the real world. The research presented in this paper explores two possible causes for the compressed distance perception in virtual environments: (1) real-time computer graphics rendering, and (2) immersive display technology. Our results show there is a significant difference in distance judgments between real and virtual environments. However, the differences between distance judgments in virtual photographic panorama environments and traditionally rendered virtual environments are small, suggesting that the display device is affecting distance judgments in virtual environments.
AN X-RAY/OPTICAL STUDY OF THE COMPLEX DYNAMICS OF THE CORE OF THE MASSIVE INTERMEDIATE-REDSHIFT CLUSTER MACSJ0717.5+3745

Using CHANDRA, we investigate the spatial temperature distribution of the intracluster medium (ICM) within 700 kpc of the center of the massive merging cluster MACSJ0717.5+3745 at z = 0.55. Combining the X-ray evidence with information about the distribution and velocities of the cluster galaxies near the core provides us with a snapshot of the three-dimensional geometry and dynamics of one of the most complex clusters studied to date. We find MACSJ0717.5+3745 to be an active triple merger with ICM temperatures exceeding 20 keV. Although radial velocity information and X-ray/optical offsets indicate that all three mergers proceed along distinctly different directions, the partial alignment of the merger axes points to a common origin in the large-scale filament south-east of the cluster core. Clear decrements in the ICM temperature observed near two of these subclusters identify the respective X-ray surface brightness peaks as remnants of cool cores; the compactness and low temperature of 5.7 keV of one of these features suggest that the respective merger, a high-velocity collision at 3,000 km s–1, is still in its very early stages. Looking beyond the triple merger, we find the large-scale filament to not only provide a spatial as well as temporal arrow for the interpretation of the dynamics of the merger events near the cluster core, but we also find tantalizing, if circumstantial, evidence for direct, large-scale heating of the ICM by contiguous infall of low-density gas from the filament.
Saturation effects in coupled lasers with homogeneous gain

The effects of saturation on the performance of two weakly coupled lasers with homogeneous gain are evaluated. Analytic steady-state results are obtained for cases where the intensity is the same in each laser. Output power is at a maximum when both lasers have the same mirror separation and a distance between them that corresponds to an integral number of wavelengths. If these conditions are changed, the result is reduced stability in addition to lower output power. A previous model, which employed third-order saturation, underpredicts the increase in output power with an increase in saturation but is qualitatively correct with regard to regimes for stable operation.
Transition Metal Catalyzed Synthesis of Arylamines and Aryl Ethers from Aryl Halides and Triflates: Scope and Mechanism.

Oxidative addition and reductive elimination are the central steps in new palladium-catalyzed chemistry that forms C–N and C–O bonds in arylamines and ethers. In the potential mechanism shown on the right the amine is formed by reductive elimination from a four-coordinate, 16-electron amido aryl complex. The use of a chelating ligand such as 1,1′-bis(diphenylphosphanyl)ferrocene (DPPF) reduces the occurrence of the competing β-hydrogen elimination. X=Br, I; R, R′=alkyl, aryl.
Wiener Process with Reflection in Non-Smooth Narrow Tubes

Wiener process with instantaneous reflection in narrow tubes of width $\epsilon\ll 1$ around axis $x$ is considered in this paper. The tube is assumed to be (asymptotically) non-smooth in the following sense. Let $V^{\epsilon}(x)$ be the volume of the cross-section of the tube. We assume that $\frac{1}{\epsilon}V^{\epsilon}(x)$ converges in an appropriate sense to a non-smooth function as $\epsilon\downarrow 0$. This limiting function can be composed by smooth functions, step functions and also the Dirac delta distribution. Under this assumption we prove that the $x$-component of the Wiener process converges weakly to a Markov process that behaves like a standard diffusion process away from the points of discontinuity and has to satisfy certain gluing conditions at the points of discontinuity.
Repeatable generalized inverse control strategies for kinematically redundant manipulators

The issue of generating a repeatable control strategy which possesses the desirable physical properties of a particular generalized inverse is addressed. The technique described is fully general and only requires a knowledge of the associated mill space of the desired inverse. While an analytical representation of the null vector is desirable, ultimately the calculations are done numerically so that a numerical knowledge of the associated full vector is sufficient. This method first characterizes repeatable strategies using a set of orthonormal basis functions to describe the null space of these transformations. The optimal repeatable inverse is then obtained by projecting the null space of the desired generalized inverse onto each of these basis functions. The resulting inverse is guaranteed to be the closest repeatable inverse to the desired inverse, in an integral norm sense, from the set of all inverses spanned by the selected basis functions. This technique is illustrated for a planar, three-degree-of-freedom manipulator and a seven-degree-of-freedom spatial manipulator. >
Three-Dimensional Modeling of Laser Sintering of a Two-Component Metal Powder Layer on Top of Sintered Layers

A three-dimensional model of selective laser sintering of a two-component loose metal powder layer on top of previously sintered layers by a single-line laser scanning is presented. A temperature-transforming model is employed to model melting and resolidification accompanied by partial shrinkage during laser sintering. The heat losses at the top surface due to natural convection and radiation are taken into account. The liquid flow of the molten low-melting-point metal powders, which is driven by capillary and gravity forces, is also considered and formulated by using Darcy’s law. The effects of the dominant processing parameters, such as laser-beam intensity, scanning velocity, and number of the existing sintered layers underneath, are investigated. DOI: 10.1115/1.2716714
Code Design for the Noisy Slepian-Wolf Problem

We consider a noisy Slepian-Wolf problem where two correlated sources are separately encoded (using codes of fixed rate) and transmitted over two independent binary memoryless symmetric channels. The capacity of each channel is characterized by a single parameter that is not known at the transmitter. System performance is evaluated by computing the set of channel parameters for which the system can successfully decode. This set is called the achievable channel parameter region (ACPR). The goal is to design systems whose ACPRs are as large as possible. The main result is the design of irregular low-density parity-check (LDPC) ensembles whose ACPRs are significantly larger than previous designs. Some previous attempts to achieve large ACPRs with LDPC codes failed because systematic codes were used. In this work, we start with systematic encoders but puncture all the systematic bits before transmission. We also show that additional gains are possible using a staggered structure which enables codes optimized for single-user channels to perform well under symmetric channel conditions. The main analysis tool is a generic density-evolution framework for the analysis of joint iterative decoding for this problem.
Then and now: Interviews with expert U.S. organizational ombudsmen

Through the stories of twenty-four pioneering U.S. organizational ombudsmen, this article explores the history of the modern organizational ombudsman role and what needs to be done to strengthen the field. Those interviewed are considered leaders in the field, many having practiced the role early in its existence and for ten or more years. They describe its evolution, citing factors such as peer-to-peer support and standards of practice that contributed to its growth and stability, and ongoing challenges, including the need for a shield law and more effective assessment and communication of the value of the role.
On the Mechanistic Origins of Toughness in Bone

One of the most intriguing protein materials found in nature is bone, a material composed of assemblies of tropocollagen molecules and tiny hydroxyapatite mineral crystals that form an extremely tough, yet lightweight, adaptive and multifunctional material. Bone has evolved to provide structural support to organisms, and therefore its mechanical properties are of great physiological relevance. In this article, we review the structure and properties of bone, focusing on mechanical deformation and fracture behavior from the perspective of the multidimensional hierarchical nature of its structure. In fact, bone derives its resistance to fracture with a multitude of deformation and toughening mechanisms at many size scales ranging from the nanoscale structure of its protein molecules to the macroscopic physiological scale.
Electronic Determination of the Modulus of Elasticity and Intrinsic Stress of Thin Films using Capacitive Bridges

We extend the method of Najafi and Suzuki [1] for the electronic determination of the modulus of elasticity and intrinsic stress of thin films using capacitive bridge structures. New theoretical concepts are introduced. The extended method does not require that the test structures be exercised to the point of snap-action.
Toric degenerations and Batyrev-Borisov duality

This is an extended example of the study of mirror symmetry via log schemes and the discrete Legendre transform on affine manifolds, introduced by myself and Bernd Siebert in "Mirror Symmetry via Logarithmic Degeneration Data I" (math.AG/0309070). In this paper, I consider the construction as it applies to the Batyrev-Borisov construction for complete intersections in toric varieties. Given a pair of reflexive polytopes with nef decompositions dual to each other, and given polarizations on the corresponding toric varieties, we construct examples of toric degenerations and their dual intersection complexes, which are affine manifolds with singularities. We show these affine manifolds are related by the discrete Legendre transform, thus showing that the Batyrev-Borisov construction is a special case of our more general construction. The description of the dual intersection complexes in terms of the combinatoricsof the setup generalises work of Haase and Zharkov in the toric hypersurface case, and similar work of Ruan. In particular, this gives a topological description of the Strominger-Yau-Zaslow fibrations on complete intersections in toric varieties.
Approximation of infinite-dimensional systems

A Fourier series-based method for approximation of stable infinite-dimensional linear time-invariant system models is discussed. The basic idea is to compute the Fourier series coefficients of the associated transfer function T/sub d/(Z) and then take a high-order partial sum. Two results on H/sup infinity / convergence and associated error bounds of the partial sum approximation are established. It is shown that the Fourier coefficients can be replaced by the discrete Fourier transform coefficients while maintaining H/sup infinity / convergence. Thus, a fast Fourier transform algorithm can be used to compute the high-order approximation. This high-order finite-dimensional approximation can then be reduced using balanced truncation or optimal Hankel approximation leading to the final finite-dimensional approximation to the original infinite-dimensional model. This model has been tested on several transfer functions of the time-delay type with promising results. >
Galaxy formation in the reionization epoch as hinted by wide field camera 3 observations of the hubble ultra deep field

We present a large sample of candidate galaxies at z ≈ 7–10, selected in the Hubble Ultra Deep Field using the new observations of the Wide Field Camera 3 that was recently installed on the Hubble Space Telescope. Our sample is composed of 20 z850-dropouts (four new discoveries), 15 Y105-dropouts (nine new discoveries) and 20 J125-dropouts (all new discoveries). The surface densities of the z850-dropouts are close to what was predicted by earlier studies, however, those of the Y105- and J125-dropouts are quite unexpected. While no Y105- or J125-dropouts have been found at AB ≤ 28.0 mag, their surface densities seem to increase sharply at fainter levels. While some of these candidates seem to be close to foreground galaxies and thus could possibly be gravitationally lensed, the overall surface densities after excluding such cases are still much higher than what would be expected if the luminosity function does not evolve from z ~ 7 to 10. Motivated by such steep increases, we tentatively propose a set of Schechter function parameters to describe the luminosity functions at z ≈ 8 and 10. As compared to their counterpart at z ≈ 7, here L* decreases by a factor of ~ 6.5 and * increases by a factor of 17–90. Although such parameters are not yet demanded by the existing observations, they are allowed and seem to agree with the data better than other alternatives. If these luminosity functions are still valid beyond our current detection limit, this would imply a sudden emergence of a large number of low-luminosity galaxies when looking back in time to z ≈ 10, which, while seemingly exotic, would naturally fit in the picture of the cosmic hydrogen reionization. These early galaxies could easily account for the ionizing photon budget required by the reionization, and they would imply that the global star formation rate density might start from a very high value at z ≈ 10, rapidly reach the minimum at z ≈ 7, and start to rise again towards z ≈ 6. In this scenario, the majority of the stellar mass that the universe assembled through the reionization epoch seems still undetected by current observations at z ≈ 6.
The flexibility of emotional attention: accessible social identities guide rapid attentional orienting.

There is extensive evidence that emotional—especially threatening—stimuli rapidly capture attention. These findings are often explained in terms of a hard-wired and relatively inflexible fear module. We propose an alternative, more flexible mechanism, arguing that motivational relevance is the crucial factor driving rapid attentional orienting. To test our hypothesis, we endowed initially neutral face stimuli with relevance by randomly assigning them to a social in-group or out-group during a 1-min learning phase, and used these faces as cues in a dot probe task to measure rapid attentional orienting. Across three experiments, we observed attentional orienting toward faces assigned to the out-group. Initial rapid orienting (after 100 ms, Experiments 1 and 2) was observed only for familiar faces for which group membership was explicitly encoded, suggesting that rapid orienting may be based on affectively charged memory traces. At a later time point (after 500 ms, Experiment 3), attention was deployed toward unfamiliar faces sharing a physical attribute (background color) with the familiar out-group faces, suggesting a more time-consuming on-line appraisal of the stimulus. The amount of attentional bias to out-group faces was correlated with individual differences in the accessibility of group identification. Our findings demonstrate that attentional prioritization mechanisms can be flexibly tuned by a brief learning phase of social identity. This is consistent with the idea that attention mechanisms subserving the selection and prioritization of emotional aspects of the environment are not static and hard-wired, but may rapidly adapt to recent changes in motivational contingencies.
Justice systems and ICT What can be learned from Europe

The rapid development of information and communication technologies (ICT) opens up new opportunities to significantly improve the administration of justice. The availability of web services, the use of electronic filing, the electronic exchange of legal documents, the possibility of on-line legislation and case law are only some examples that are spurring judicial administrations around the world to rethink their current functions and activities. ICT can be used to enhance efficiency, access, timeliness, transparency and accountability, thus helping judiciaries to provide adequate services. As many empirical examples show, this is, however, not always the case. The interaction between technology and highly regulated organisations, such as courts, may often lead to unexpected results. Europe, with its different institutional settings and experiences, allows the exploration of a variety of solutions that can be implemented to support the administration of justice. Most importantly, it also provides the opportunities for a unique insight into the dynamics and problems that may characterize such experiences. This article seeks to provide an empirically derived account on the uses of ICT within the courts and for judicial data interchange. The article is based on data collected through several research projects by the Research Institute on Judicial Systems of the Italian National Research Council, in partnership with other European institutions, including Universities and Ministries of Justice.
Control of industrial robots that have transmission elasticity

A control scheme is presented for electrically driven, industrial robots that have transmission elasticity. Some feedback structures that have been described in the past have an inner control loop to cancel the elastic coupling torque between motor and link. An outer feedback loop is then used for the control of the arm position. A refinement of such a control scheme is analyzed using singular perturbation methods. A broad spectrum of control algorithms that were originally designed under the assumption of ideal, rigid joints can now be extended to the elastic transmission case with minor modifications. One contribution is that exact cancellation of the elastic torque is not necessary. In fact, the elasticity effects in some robots can be adequately damped by simply adding only a term that is proportional to the differential speed (difference between link velocity and motor velocity). Experimental results are also presented. >
Proactive Software Tampering Detection

With the advent of digital technologies, digital content piracy has become a growing concern. Unauthorized music and movie copying are eating a big bite of the profit of the record industry and the movie studios. Software piracy has also cost software industry billions of dollars each year. The success of the content protection technologies in a large part depends on the capability of protecting software code against tampering and reverse-engineering. The problem is difficult because the software runs on a hacker’s machine which has full control over its execution. In this paper, we focus on the detection of software tampering. We shall present a proactive way to detect the on-going tampering process during software executions before the hacking completely succeeds. We thus can prevent the potential damage from occurring. The integrity check failures triggered during software execution are logged in a way that cannot go undetected later. This clearly provides strong tamper evidence to do both pre and post-compromise forensics analysis. In particular, we consider real world scenarios where the software users have a long term business interest with the software distributor, and where a detection of tampering can bar a hacker from further business. We believe the proactive detection of tampering is of great importance and value in this type of scenario.
Bone Disease and Idiopathic Hypercalciuria

Observational and epidemiologic studies alike have shown that idiopathic hypercalciuric (IH) stone-forming patients typically show bone mineral density scores that are significantly lower than those observed for age- and sex-matched normal subjects or those for nonhypercalciuric stone-forming patients. Most of these studies have relied on changes in bone mineral density and have not explored the mechanism(s) involved. There have been a small number of studies that have relied on dynamic bone histomorphometry to ascertain the nature of the bone defect in IH patients. When performed, these studies clearly have shown increased bone resorption and high bone turnover in patients with fasting hypercalciuria whereas suppressed bone formation indices are the most consistent finding in patients with the absorptive variant of IH. The causes of this apparent difference in bone remodeling between the 2 variants of IH still is uncertain. Available evidence suggests that potential mechanisms may be dependent in large part to genetic, metabolic, and nutritional causes of hypercalciuria and bone loss in patients with IH.
Cooperation in the commons with unobservable actions

We model a dynamic common property resource game with unobservable actions and non-linear stock dependent costs. We propose a strategy profile that generates a worst perfect equilibrium in the punishment phase, thereby supporting cooperation under the widest set of conditions. We show under what set of parameter values for the discount rate, resource growth rate, harvest price, and the number of resource users, this strategy supports cooperation in the commons as a subgame perfect equilibrium. The strategy profile that we propose, which involves harsh punishment after a defection followed by forgiveness, is consistent with human behavior observed in experiments and common property resource case studies.
The Accruals Anomaly and Company Size

Research has shown that a trading strategy based on publicly available accounting accrual information can earn abnormal returns of approximately 10 percent in the year after it is applied. This article reports a study of whether this “accruals anomaly” is sensitive to company size. The empirical results suggest that the interaction between company size and accruals provides incremental information about future returns and that the accruals anomaly is not independent of company size. The negative abnormal returns when an accruals-anomaly strategy is applied come primarily from the larger companies, and the positive abnormal returns come from the smaller companies.
The 1985-94 global real estate cycle : its casues and consequences

The peak of the first global real estate boom was reached around 1990 in most Organization for Economic Cooperation and Development (OECD) countries. Asset inflation was massive: in office markets across Europe, capital values rose 400 percent between 1980 and 1990, accelerating after 1986 - while average consumer price inflation went up only 150 percent. Property values have declined sharply since 1990, with most property markets losing at least 20 percent in nominal terms the first year of the crash's onset. Cumulative drops in capital value often reached 50 percent by the end of 1993. This pattern of a sustained buildup, usually peaking in 1990, followed by a sharp fall in nominal values, has been encountered in most OECD markets and in several NIE countries. Real estate booms and busts are recurring events, says the author, but real estate volatility on the scale and with the intensity just experience is costly and destructive. Real resources are misallocated, and the impact on the banking system, on households, and on the economy can be lasting. The author surveys the global real estate cycle of 1985-94, trying to identify domestic and international factors that triggered this new phenomenon of global real estate volatility. The authors intent: Assuming that the globalization of financial markets is irreversible, can we separate unique factors from recurring ones in this first global cycle? Can we map generic policy lessons and identify policy priorities and research agendas? Can we identify factors that accentuate real estate price and investment volatility? Four domestic factors lay behind the unusual volatility of this first global cycle, says the author: the liberalization and deregulation of capital markets, a distorted incentive structure that often stimulated the use of debt, new macroeconomic tools and occasional policy errors, and the structure of the real estate sector itself. The wide-ranging survey includes a proposal for research in certain areas, and offers some diagnosis. For example: If the global real estate crash has publicized one thing, it is the poor quality of information on real estate markets.
Large-eddy and unsteady RANS simulations of a shock-accelerated heavy gas cylinder

Two-dimensional numerical simulations of the Richtmyer–Meshkov unstable “shock-jet” problem are conducted using both large-eddy simulation (LES) and unsteady Reynolds-averaged Navier–Stokes (URANS) approaches in an arbitrary Lagrangian–Eulerian hydrodynamics code. Turbulence statistics are extracted from LES by running an ensemble of simulations with multimode perturbations to the initial conditions. Detailed grid convergence studies are conducted, and LES results are found to agree well with both experiment and high-order simulations conducted by Shankar et al. (Phys Fluids 23, 024102, 2011). URANS results using a k–L approach are found to be highly sensitive to initialization of the turbulence lengthscale L and to the time at which L becomes resolved on the computational mesh. It is observed that a gradient diffusion closure for turbulent species flux is a poor approximation at early times, and a new closure based on the mass-flux velocity is proposed for low-Reynolds-number mixing.
Algorithmic pricing via virtual valuations

Algorithmic pricing is the computational problem that sellers (e.g.,in supermarkets) face when trying to set prices for their items to maximize their profit in the presence of a known demand. Guruswami etal. (SODA, 2005) proposed this problem and gave logarithmic approximations (in the number of consumers) for the unit-demand and single-parameter cases where there is a specific set of consumers and their valuations for bundles are known precisely. Subsequently several versions of the problem have been shown to have poly-logarithmic in approximability. This problem has direct ties to the important open question of better understanding the Bayesian optimal mechanism in multi-parameter agent settings; however, for this purpose approximation factors logarithmic in the number of agents are inadequate. It is therefore of vital interest to consider special cases where constant approximations are possible. We consider the unit-demand variant of this pricing problem. Here a consumer has a valuation for each different item and their value for aset of items is simply the maximum value they have for any item in the set. Instead of considering a set of consumers with precisely known preferences, like the prior algorithmic pricing literature, we assume that the preferences of the consumers are drawn from a distribution. This is the standard assumption in economics; furthermore, the setting of a specific set of customers with specific preferences, which is employed in all of the prior work in algorithmic pricing, is a special case of this general Bayesian pricing problem, where there is a discrete Bayesian distribution for preferences specified by picking one consumer uniformly from the given set of consumers. Notice that the distribution over the valuations for the individual items that this generates is obviously correlated. Our work complements these existing works by considering the case where the consumer's valuations for the different items are independent random variables. Our main result is a constant approximation algorithm for this problem that makes use of an interesting connection between this problem and the concept of virtual valuations from the single-parameter Bayesian optimal mechanism design literature.
Shear Viscosity in the O(N) Model

We compute the shear viscosity in the O(N) model at first nontrivial order in the large N expansion. The calculation is organized using the 1/N expansion of the 2PI effective action (2PI-1/N expansion) to next-to-leading order, which leads to an integral equation summing ladder and bubble diagrams. We also consider the weakly coupled theory for arbitrary N, using the three-loop expansion of the 2PI effective action. In the limit of weak coupling and vanishing mass, we find an approximate analytical solution of the integral equation. For general coupling and mass, the integral equation is solved numerically using a variational approach. The shear viscosity turns out to be close to the result obtained in the weak-coupling analysis.
CONDITIONAL ASIAN OPTIONS

Conditional Asian options are recent market innovations, which offer cheaper and long-dated alternatives to regular Asian options. In contrast with payoffs from regular Asian options which are based on average asset prices, the payoffs from conditional Asian options are determined only by average prices above certain threshold. Due to the limited inclusion of prices, conditional Asian options further reduce the volatility in the payoffs than their regular counterparts and have been promoted in the market as viable hedging and risk management instruments for equity-linked life insurance products. There has been no previous academic literature on this subject and practitioners have only been known to price these products by simulations. We propose the first analytical approach to computing prices and deltas of conditional Asian options in comparison with regular Asian options. In the numerical examples, we put to the test some cost-benefit claims by practitioners. As a by-product, the work also presents some distributional properties of the occupation time and the time-integral of geometric Brownian motion during the occupation time.
Distributed stable matching problems with ties and incomplete lists

We consider the Stable Marriage Problem and the Stable Roommates Problem in presence of ties and incomplete preference lists. They can be solved by centralized algorithms, but this requires to make public preference lists, something that members would prefer to avoid for privacy reasons. This motivates a distributed formulation to keep privacy. We propose a distributed constraint approach that solves all the considered problems, keeping privacy.
A backroom mission operations center for TechSat 21

The TechSat 21 satellite program is an Air Force Research Laboratory (AFRL) technology initiative which has an objective to demonstrate and validate microsatellite cluster system concepts and enabling technologies. The primary experimental objectives are to demonstrate formation flying algorithms and technologies for clustered satellites, and to demonstrate autonomous cluster and spacecraft operations. TechSat 21 consists of three satellites which will fly in various configurations with variable separation distances. Command and control of a cluster of satellites with multiple heterogeneous experimental objectives poses several challenges from a ground perspective. To assist in operating TechSat 21, AFRL is developing a backroom Mission Operations Center (MOC) which will be capable of performing, among other tasks: planning and scheduling; command generation; state-of-health (SOH) monitoring; telemetry playbacks; fault detection, isolation, and resolution (FDIR); data storage; and payload data analysis. The objective of this paper is to describe the MOC architecture, highlight the key components, and outline its planned operational use.
Quadratic Concavity and Determinacy of Equilibrium

One of the central features of classical models of competitive markets is the generic determinacy of competitive equilibria. For smooth economies with a finite number of commodities and a finite number of consumers, almost all initial endowments admit only a finite number of competitive equilibria, and these equilibria vary (locally) smoothly with endowments; thus equilibrium comparative statics are locally determinate. This paper establishes parallel results for economies with finitely many consumers and infinitely many commodities. The most important new condition we introduce, quadratic concavity, rules out preferences in which goods are perfect substitutes globally, locally, or asymptotically. Our framework is sufficiently general to encompass many of the models that have proved important in the study of continuous-time trading in financial markets, trading over an infinite time horizon, and trading of finely differentiated commodities.
Measuring Income from Family Enterprises With Household Surveys

The accuracy of the measured income of family enterprises is a matter of importance in studies of, interalia, human capital, income distribution and consumption behavior. One may measure this income as part of a household survey or through an enterprise survey. Household surveys have advantages over enterprise surveys in studying the income of the self-employed. They capture more of the truly small-scale one-person enterprises, and there is a wealth of information that can be utilized in the study of enterprise income, such as education of other family members, migration history, and possibly employment history. Household surveys also allow one to study the role of family enterprises within the context of the household, in relation to labor supply, risk sharing, enterprise start-up, and asset formation. Thus, household surveys offer a better perspective for study of living standards and poverty. By comparison, enterprise surveys are able to extract more detailed information about the enterprises than household surveys can. Interviewers of households spend considerable time in gathering information that, for studying enterprises, has no value. Enterprise surveys fully focus on production. Measures of inputs and outputs are the primary objective of the survey, and considerable effort goes into obtaining good measures of these. This paper examines the three enterprise income values that one may derive from the survey modules of the Living Standards Surveys.