cssi/SciSciGPT-SciSciNet huggingface dataset:
Geometric packing under non-uniform constraints

We study the problem of discrete geometric packing. Here, given weighted regions (say in the plane) and points (with capacities), one has to pick a maximum weight subset of the regions such that no point is covered more than its capacity. We provide a general framework and an algorithm for approximating the optimal solution for packing in hypergraphs arising out of such geometric settings. Using this framework we get a flotilla of results on this problem (and also on its dual, where one wants to pick a maximum weight subset of the points when the regions have capacities). For example, for the case of fat triangles of similar size, we show an (1)-approximation and prove that no PTAS is possible. See [ehr-gpnuc-11] for the full version of the paper.
Singularities of lagrangian mean curvature flow: monotone case

We study the formation of singularities for the mean curvature flow of monotone Lagrangians in $\C^n$. More precisely, we show that if singularities happen before a critical time then the tangent flow can be decomposed into a finite union of area-minimizing Lagrangian cones (Slag cones). When $n=2$, we can improve this result by showing that each connected components of the rescaled flow converge to an area-minimizing cone, as opposed to possible non-area minimizing union of Slag cones. In the last section, we give specific examples for which such singularity formation occurs.
Arm’s Length Financing and Innovation: Evidence from Publicly Traded Firms

Using a large panel of U.S. companies, I document that firms that rely more on arm’s length financing, such as public debt and equity, innovate more and have higher-quality innovations than firms that use other sources, such as relationship-based bank financing. I hypothesize that one possible reason for this finding is the greater flexibility and tolerance to experimentation associated with arm’s length financing. I find support for this hypothesis by showing that firms with more arm’s length financing have greater volatility of innovative output, and are more likely to innovate in new technological areas. Furthermore, focusing only on bank financing, I demonstrate that firms have more novel innovations if they borrow from multiple banks, use predominantly credit lines, and have less intense covenants. I address potential endogeneity concerns by using instrumental variable analysis, and by showing that innovation increases significantly after new public debt offerings and seasoned equity offerings, but d...
A Message-Passing Receiver for BICM-OFDM Over Unknown Clustered-Sparse Channels

We propose a factor-graph-based approach to joint channel-estimation-and-decoding (JCED) of bit-interleaved coded orthogonal frequency division multiplexing (BICM-OFDM). In contrast to existing designs, ours is capable of exploiting not only sparsity in sampled channel taps but also clustering among the large taps, behaviors which are known to manifest at larger communication bandwidths. In order to exploit these channel-tap structures, we adopt a two-state Gaussian mixture prior in conjunction with a Markov model on the hidden state. For loopy belief propagation, we exploit a “generalized approximate message passing” (GAMP) algorithm recently developed in the context of compressed sensing, and show that it can be successfully coupled with soft-input soft-output decoding, as well as hidden Markov inference, through the standard sum-product framework. For N subcarriers and any channel length L<;N, the resulting JCED-GAMP scheme has a computational complexity of only O(N log2 N +N|S|), where |S| is the constellation size. Numerical experiments using IEEE 802.15.4a channels show that our scheme yields BER performance within 1 dB of the known-channel bound and 3-4 dB better than soft equalization based on LMMSE and LASSO.
k-means requires exponentially many iterations even in the plane

The k-means algorithm is a well-known method for partitioning n points that lie in the d-dimensional space into k clusters. Its main features are simplicity and speed in practice. Theoretically, however, the best known upper bound on its running time (i.e. O(nkd)) is, in general, exponential in the number of points (when kd=Ω(n log n)). Recently, Arthur and Vassilvitskii [2] showed a super-polynomial worst-case analysis, improving the best known lower bound from Ω(n) to 2Ω(√n) with a construction in d=Ω(√n) dimensions. In [2] they also conjectured the existence of super-polynomial lower bounds for any d≥ 2. Our contribution is twofold: we prove this conjecture and we improve the lower bound, by presenting a simple construction in the plane that leads to the exponential lower bound 2Ω(n).
Two notes on notation

(1992). Two Notes on Notation. The American Mathematical Monthly: Vol. 99, No. 5, pp. 403-422.
Charmed hadron asymmetries in the intrinsic charm coalescence model

Abstract Fermilab experiment E791, measuring charmed hadron production in π − A interactions at 500 GeV with high statistics, has observed a strong asymmetry between the hadroproduction cross sections for leading D mesons which contain projectile valence quarks and the non-leading charmed mesons without projectile valence quarks. Such correlations of the charge of the D meson with the quantum numbers of the beam hadron explicitly contradict the factorization theorem in perturbative QCD which predicts that heavy quarks hadronize through a jet fragmentation function that is independent of the initial state. The E791 experiment also measures Λ c / Λ c and D s / D s production asymmetries as well as asymmetries in D D pair production. We examine these asymmetries and the fractional longitudinal momentum, x F , distributions for single and pairs of charmed hadrons within a two-component model combining leading-twist gg and q q fusion sub-processes with charm production from intrinsic heavy quark Fock states. A key feature of this analysis is intrinsic charm coalescence, the process by which a charmed quark in the projectile's Fock state wave function forms charmed hadrons by combining with valence quarks of similar rapidities.
Can guest worker schemes reduce illegal migration

The authors analyze recent efforts at international cooperation to limit illegal migration, particularly through the use of legal migration avenues like guest worker schemes. They show that while guest worker schemes may be desirable as an avenue of international migration, they are an inefficient instrument to induce cooperation on illegal migration. On the one hand, guest worker schemes suffer from a negative selection problem relative to illegal migration, which tends to erode their attractiveness to source countries. On the other hand, guest worker schemes increase total (legal and illegal) migration which make them a costly compensating device for the host country. Moreover, guest worker schemes create additional pressure on host countries to implement tough laws against illegal immigration even when the host finds such laws undesirable. Thus, less favorable treatment of illegal immigrants, as in California Proposition 187, may be an inevitable rather than incidental outcome of reliance on guest worker schemes. In contrast, countries that are willing to use transfers and other forms of economic assistance to induce source countries to cooperate can afford relatively liberal treatment of illegal immigrants.
Multipole correction in synchrotrons

Novel methods of correcting dynamic nonlinearities resulting from the multipole content of a synchrotron are discussed. In simplest form, correction elements are placed at the center (C) of the accelerator half-cells as well as near the focusing (F) and defocusing (D) quadrupoles. In a first approximation, the corrector strengths follow Simpson's rule. The F, C, and D correctors permit direct control of horizontal, coupled, and vertical motion. For example, second-order sextupole nonlinearities can be corrected with F, C, and D octupoles. Generalizations and variations of the methods are described, and applications to the SCC (Superconducting Super Collider), LHC (Large Hadron Collider) AHF, and HERA (Hadron-Electron Ring Accelerator) projects are discussed. Correction by three or more orders of magnitude can be obtained, and simple solutions to a fundamental problem in synchrotrons are demonstrated. >
Cluster Models for Electronic Structure of Oxide Ceramics

Recent progress in using cluster models to calculate electronic structure of oxide ceramics such as transition-metal monoxides, zirconia, α-alumina, ruby, and copper-based superconducting oxides is reviewed. The self-consistent field local density theory is used to find potentials, energy levels, and wave functions for a fragment consisting of N atoms embedded in the infinite solid. The single-particle spectra are compared with photoelectron and optical data, and with X-ray absorption and emission. Total energy calculations provide cohesive energies for prediction of relative stability of defect structures and lattice relaxation in the vicinity of impurities. A brief description is given of surface-structure calculations for an α-alumina (0001) surface.
Enantioselective synthesis and application of the highly fluorescent and environment-sensitive amino acid 6-(2-dimethylaminonaphthoyl) alanine (DANA)

6-(2-Dimethylaminonaphthoyl) alanine (DANA) was prepared via an enantioselective synthesis and incorporated into the S-peptide of RNase S establishing the large changes in fluorescence that can occur upon peptide–protein interaction.
Multiply loaded magneto-optical trap.

We report a two-chambered, differentially pumped system that permits rapid collection of trapped atoms with a vapor cell magneto-optical trap (MOT) and efficient transfer of these atoms to a second MOT in a lower-pressure chamber. During the transfer the atoms are guided down a long, thin tube by a magnetic potential, with 90(15%) transfer efficiency. By multiply loading, we accumulate and hold as many as 30 times the number collected by the vapor cell MOT. By thus separating the collection and holding functions of a MOT, we can collect as many as 1.5(0.6) × 1010 rubidium atoms and hold them for longer than 100 s, using inexpensive low-power diode lasers.
LARGE EXTRA DIMENSIONS: BECOMING ACQUAINTED WITH AN ALTERNATIVE PARADIGM

This is a colloquium style pedagogical introduction to the paradigm of large extra dimensions. This talk was delivered at various universities including UCLA (1999), Technion (2000), DESY (2001), University of Pisa (2001), UBC (2002), NYU (2002), University of Nantes (2003), Bern University (2003), Max-Planck Institute/Munich University (2003), University of Padova (2003), University of Minnesota (2005).
Disaggregating the return on investment to IT capital

DISAGGREGATING THE CENTER FOR RESEARCH ON INFORMATION TECHNOLOGY AND ORGANIZATIONS University of California, Irvine 3200 Berkeley Place Irvine, California 92697-4650 and Graduate School of Management University of California, Irvine Email: Vgurbaxa@uci.edu, Npmelvil@uci.edu and Kkraemer@uci.edu AUTHORS: Vijay Gurbaxani Nigel Melville Kenneth Kraemer RETURN ON INVESTMENT TO IT CAPITAL SEPTEMBER 11, 1998 Acknowledgement: This research has been supported by grants from the CISE/IIS/CSS Division of the U.S. National Science Foundation and the NSF Industry/University Cooperative Research Center (CISE/EEC) to the Center for Research on Information Technology and Organizations (CRITO) at the University of California, Irvine. Industry sponsors include: ATL Products, the Boeing Company, Bristol-Myers Squibb, Canon Information Systems, IBM, Nortel Networks, Rockwell International, Microsoft, Seagate Technology, Sun Microsystems, and Systems Management Specialists (SMS).
Managerial beliefs and incentive policies

Abstract This article examines incentive contracts under moral hazard when a principal and agents disagree about the likelihood that a task will succeed. The direction of disagreement alters the effectiveness of monetary incentives. The principal's optimal contract is a relative performance evaluation when she is more optimistic than the agents, and a joint performance evaluation when she is less optimistic. We further show why disagreement may prevail in organizations by considering a simple job assignment problem.
Optimal deterministic routing and sorting on the congested clique

Consider a clique of n nodes, where in each synchronous round each pair of nodes can exchange O(log n) bits. We provide deterministic constant-time solutions for two problems in this model. The first is a routing problem where each node is source and destination of n messages of size O(log n). The second is a sorting problem where each node i is given n keys of size O(log n) and needs to receive the ith batch of n keys according to the global order of the keys. The latter result also implies deterministic constant-round solutions for related problems such as selection or determining modes.
Instantons, scale invariance and Lorentz invariance in matrix theory

Abstract In this paper we consider features of graviton scattering in Matrix theory compactified on a 2-torus. The features which interest us can only be determined by nonperturbative effects in the corresponding 2+1 dimensional super Yang Mills theory. We show that the superconformal symmetry of strongly coupled Super Yang Mills Theory in 2 + 1 dimensions almost determines low energy, large impact parameter ten dimensional graviton scattering at zero longitudinal momentum in the Matrix model of IIB string theory. We then show that amplitudes involving arbitrary transverse momentum transfer are governed by instanton processes similar to the Polchinski Pouliot process. Finally we consider the influence of instantons on a conjectured nonrenormalization theorem. This theorem is violated by instanton processes. Far from being a problem, this fact is seen to be crucial to the consistency of the IIB interpretation. We suggest that the SO(8) invariance of strongly coupled SYM theory may lead to a proof of eleven dimensional Lorentz invariance.
Conceptual design of a 1-MW CW X-band transmitter for planetary radar

A proposed conceptual design for increasing the output power of an existing X-band planetary radar transmitter from 365 kW to 1 MW CW is discussed. The basic transmitter system requirements as dictated by the specifications for the radar are discussed. The characteristics and expected performance of the high-power klystron are considered, and the transmitter power amplifier system is discussed. Also discussed is the design of the exciter system. Two alternative feed systems for delivering the 1-MW CW signal to the antenna system are described. The expected performance of the beam supply, heat exchanger, and monitor and control devices is presented. An assessment of the state-of-the-art technology to meet system requirements is given, and possible areas of difficulty are summarized. >
Characterization of Active Main Belt Object P/2012 F5 (Gibbs): A Possible Impacted Asteroid

In this work, we characterize the recently discovered active main belt object P/2012 F5 (Gibbs), which was discovered with a dust trail >7' in length in the outer main belt, 7 months prior to aphelion. We use optical imaging obtained on UT 2012 March 27 to analyze the central condensation and the long trail. We find B-band and R-band apparent magnitudes of 20.96 ± 0.04 mag and 19.93 ± 0.02 mag, respectively, which give an upper limit on the radius of the nucleus of 2.1 km. The geometric scattering cross-section of material in the trail was ~4 × 108 m2, corresponding to a mass of ~5 × 107 kg. Analysis of infrared images taken by the Wide-field Infrared Survey Explorer in 2010 September reveals that the object was below the detection limit, suggesting that it was less active than it was during 2012, or possibly inactive, just six months after it passed through perihelion. We set a 1σ upper limit on its radius during this time of 2.9 km. P/2012 F5 (Gibbs) is dynamically stable in the outer main belt on timescales of ~1 Gyr, pointing toward an asteroidal origin. We find that the morphology of the ejected dust is consistent with it being produced by a single event that occurred on UT 2011 July 7 ± 20 days, possibly as the result of a collision with a small impactor.
Voltage-gated ion channels

Voltage-dependent ion channels are membrane proteins that conduct ions at high rates regulated by the voltage across the membrane. They play a fundamental role in the generation and propagation of the nerve impulse and in cell homeostasis. The voltage sensor is a region of the protein bearing charged amino acids that relocate upon changes in the membrane electric field. The movement of the sensor initiates a conformational change in the gate of the conducting pathway thus controlling the flow of ions. Major advances in molecular biology, spectroscopy, and structural techniques are delineating the main features and possible structural changes that account for the function of voltage-dependent channels.
Two low-cost phased arrays

In a phased array antenna, the phase shifters (or T/R modules in an active aperture phased array) with their beam-steering control circuitry along with the feed network account for the major hardware cost. This paper presents two antenna array configurations that use simpler feed, simpler phase-shifting and simpler beam-steering control circuitry for realizing low-cost phased arrays. Both are lens configurations. The first one uses a Radant lens, which provides a medium that is loaded with diodes and provides the needed phase shift by switching the diodes on and off. The other configuration employs a ferroelectric dielectric material whose dielectric constant can be varied with an applied DC bias voltage. It is shown that the ferroelectric lens may have further advantages of smaller thickness, simpler beam-steering controls and lower cost.
A Comparison of Drug Use and Adjustment in Urban Adolescent Children of Substance Abusers

Children of alcoholics and other drug abusers are at elevated risk for substance abuse and other related psychosocial problems. Adolescents with a positive family history for drug abuse or alcoholism were compared to a similar group of low-SES, urban youth who were at risk for school failure but did not report any family history of substance abuse. A survey of depression, self-esteem, behavioral competence and dysfunction, and drug/alcohol use found that, overall, adolescents with a positive family history (FHP) for substance abuse exhibited more use of illicit drugs compared to those with a negative family history (FHN). There were also a greater number of FHP cases which fell into the clinical range on the psychosocial measures of behavioral dysfunction and depression compared to FHN youth. There were differential effects for boys versus girls, with FHP girls exhibiting a greater number of problem cases. Implications for substance abuse prevention with urban youth are discussed. [Translations are provid...
Filling-invariants at infinity for manifolds of nonpositive curvature

In this paper we construct and study isoperimetric functions at infinity for Hadamard manifolds. These quasi-isometry invariants give a measure of the spread of geodesics in such a manifold.
Functionalized Corannulene Carbocations: A Structural Overview

A detailed structural overview of a family of bowl-shaped polycyclic aromatic carbocations of the type [C20 H10 R](+) with different R functionalities tethered to the interior surface of corannulene (C20 H10 ) is provided. Changing the identity of the surface-bound groups through alkyl chains spanning from one to four carbon atoms and incorporating a different degree of halogenation has led to the fine tuning of the bowl structures and properties. The deformation of the corannulene core upon functionalization has been revealed based on X-ray crystallographic analysis and compared for the series of cations with R=CH3 , CH2 Cl, CHCl2 , CCl3 , CH2 CH3 , CH2 CH2 Cl, and CH2 CH2 Br. The resulting carbocations have been isolated with several metal-based counterions, varying in size and coordinating abilities ([AlCl4 ](-) , [AlBr4 ](-) , [(SnCl)(GaCl4 )2 ](-) , and [Al(OC(CF3 )3 )4 ](-) ). A variety of aggregation patterns in the solid state has been revealed based on different intermolecular interactions ranging from cation-anion to π-π stacking and to halogen⋅⋅⋅π interactions. For the [C20 H10 CH2 Cl](+) ion crystallized with several different counterions, the conformation of the R group attached to the central five-membered ring of corannulene moiety was found to depend on the solid-state environment defined by the identity of anions. Solution NMR and UV/Vis investigations have been used to complement the X-ray diffraction studies for this series of corannulene-based cations and to demonstrate their different association patterns with the solvent molecules.
Deformation microstructures and selected examples of their recrystallization

The elements that are needed to describe a deformation structure—grains, grain boundaries, macroscale banding within crystals, cell blocks, geometrically necessary boundaries and incidental dislocation boundaries (cell boundaries)—are presented and described for fcc metals and alloys of medium to high stacking fault energy. Pertinent to this quantitative description are the local orientations, structural morphology, different boundary misorientations and spacings as a function of strain and deformation conditions. Three specific examples are given in which particular aspects of the deformation structure are shown to direct the recrystallization behavior. Copyright © 2001 John Wiley & Sons, Ltd; first published by Riso National Laboratory.
Overview of multidatabase transaction management

A multidatabase system (MDBS) is a facility that allows users access to data located in multiple autonomous database management systems (DBMSs). In such a system, global transactions are executed under the control of the MDBS. Independently, local transactions are executed under the control of the local DBMSs. Each local DBMS integrated by the MDBS may employ a different transaction management scheme. In addition, each local DBMS has complete control over all transactions (global and local) executing at its site, including the ability to abort at any point any of the transactions executing at its site. Typically, no design or internal DBMS structure changes are allowed in order to accommodate the MDBS. Furthermore, the local DBMSs may not be aware of each other, and, as a consequence, cannot coordinate their actions. Thus, traditional techniques for ensuring transaction atomicity and consistency in homogeneous distributed database systems may not be appropriate for an MDBS environment. The objective of this paper is to provide a brief review of the most current work in the area of multidatabase transaction management. We first define the problem and argue that the multidatabase research will become increasingly important in the coming years. We then outline basic research issues in multidatabase transaction management and review recent results in the area. We conclude the paper with a discussion of open problems and practical implications of this research.
How Ready are Postsecondary Institutions for Students who are d/Deaf or Hard-of-Hearing?

Educational policy in the United States is increasingly focused on the need for individuals to be academically ready for postsecondary education experiences. The focus of these initiatives, however, centers primarily on individuals and their competencies and characteristics, and not on the capacities of postsecondary institutions to serve them. This article uses the lens of students who are d/Deaf or hard-of-hearing (DHH) to explore ways in which college readiness can be conceptualized as overlapping continuums of preparedness for both individuals and institutions. The article first summarizes research on students who are DHH and their readiness across core domains of academic preparation, language and communication, and soft skills. The article then discusses considerations at the institutional level such as accommodations, direct vs. mediated communication, student disclosure rates, and their level of accessibility for students who have a different academic, linguistic, and cultural experience than most institutional infrastructure is designed to serve. We conclude with considerations for future investigation and an expansion of the dialog around readiness and postsecondary education.
Rejuveniles and growth

Abstract Rejuveniles are “people who cultivate tastes and mind-sets traditionally associated with those younger than themselves” [Noxon, C., 2006. Rejuvenile. Crown Publishers]. In this paper, we study a standard AK growth model of overlapping generations populated by rejuveniles. For our purposes, rejuveniles are old agents who derive utility from “keeping up” their consumption with that of the current young. We find that such cross-generational keeping up is capable of generating interesting equilibrium growth dynamics, including growth cycles. No such growth dynamics is possible either in the baseline model, one where no such generational consumption externality exists, or for almost any other form of keeping up. Steady-state growth in a world with rejuveniles may be higher than that obtained in the baseline model.
Speculation and Risk Sharing with New Financial Assets

While the traditional view of …nancial innovation emphasizes the risk sharing role of new …nancial assets, belief disagreements about these assets naturally lead to speculation, which represents a powerful economic force in the opposite direction. This paper investigates the eect of …nancial innovation on portfolio risks in an economy when both the risk sharing and the speculation forces are present. Financial assets provide hedging services but they are also subject to speculation because traders do not necessarily agree about their payos. I de…ne the average variance of traders'net worths as a measure of portfolio risks for this economy, and I decompose it into two components: the uninsurable variance, de…ned as the average variance that would obtain if there were no belief disagreements, and the speculative variance, de…ned as the residual variance that results from speculative trades based on belief disagreements. Financial innovation always decreases the uninsurable variance because new assets increase the possibilities for risk sharing. My main result shows that …nancial innovation also always increases the speculative variance. This is true even if traders completely agree about the payos of new assets. The intuition behind this result is the hedge-more/bet-more eect: Traders use new assets to hedge their bets on existing assets, which in turn enables them to place larger bets and take on greater risks. My second set of results concern endogenous …nancial innovation. When belief disagreements are su¢ ciently large, a pro…t seeking market maker introduces assets that maximize the average variance among all possible choices, completely disregarding the risk sharing motive for …nancial innovation. My third set of results concern a calibration of the model in the context of the GDP indexed assets proposed by Athanasoulis and Shiller (2001). When traders have reasonable amounts of belief disagreements, these assets would have the unintended consequence of increasing their consumption risks.
A REVIEW OF GLAUCOMA LITERATURE

A review of literature on glaucoma from 1966 through 1968. Thirty-five articles on the subject of glaucoma are reviewed and summarized with regard to: incidence, heredity, ophthalmoscopy, visual fields, tonometry, etiology, medical management and miscellaneous considerations.
Segmentation for robust tracking in the presence of severe occlusion

Tracking an object in a sequence of images can fail due to partial occlusion or clutter. Robustness to occlusion can be increased by tracking the object as a set of "parts" such that not all of these are occluded at the same time. However, successful implementation of this idea hinges upon finding a suitable set of parts. In this paper we propose a novel segmentation, specifically designed to improve robustness against occlusion in the context of tracking. The main result shows that tracking the parts resulting from this segmentation outperforms both tracking parts obtained through traditional segmentations, and tracking the entire target. Additional results include a statistical analysis of the correlation between features of a part and tracking error, and identifying a cost function that exhibits a high degree of correlation with the tracking error.
Regio- and Enantioselective Cyclization of Epoxy Alcohols Catalyzed by a [CoIII(salen)] Complex.

The intramolecular cyclization of epoxy alcohols was catalyzed with excellent regio- and enantiocontrol by a [CoIII(salen)] complex. High endo selectivity was observed for the enantioselective cyclization of terminal epoxy alcohols [Eq. (a)], while the reaction of meso substrates produced novel cyclic and bicyclic ethers in good yields and high enantiopurity. TBME=tert-butyl methyl ether.
Comments on model validation

The present paper points out the importance and usefulness of recognizing the separate roles of processes and geometric structures in predictive modeling of the performance of a nuclear waste repository or underground injection disposal of toxic wastes. Based on this, a validation procedure is proposed. Furthermore, two stages and three elements of validation are described and discussed. Finally, comments are made on the choice of measurables to be used to compare modeling results and field data in the validation procedure.
Application of the thioimidate cyclopropane rearrangement to heterocyclic synthesis. Preparation of diaryl pyrrolines

Substituent effects on the thioimidate cyclopropane rearrangement and factors affecting regioselectivity are reported. Palladium-mediated coupling of the pyrrolothiomethylimidate rearrangement products with Grignard reagents provides diaryl pyrrolines in good yields.
Imperfect Food Certification, Opportunistic Behaviors and Detection

In response to the recent outbreaks of food-borne illness, the 'Good Agricultural Practices' program has been widely adopted to ensure consistency of food safety. This paper presents a theoretical framework to analyze the performance of the program with respect to output quality based on the assumption of predetermined productive capacity (farm size), heterogeneous farms and exogenous detection. Our main results are: (i) farms respond to the monitoring and enforcement not only by reducing fraudulent output, but also by increasing truly high-safety output until the perfect compliance level is achieved. (ii) the monitoring agency takes farm strategies as given and its optimal inspection policies are: If the monitoring budget is not enough to cover the necessary inspection cost of achieving perfect high-safety output level, it will allocate resources to farms with larger size and lower costs; If the budget is enough to obtain perfect level of high-safety output but is not enough to eliminate fraudulent output completely, the monitoring agency will expend equal effort on all the farms.
Anytime coalition structure generation with worst case guarantees

Coalition formation is a key topic in multiagent systems. One would prefer a coalition structure that maximizes the sum of the values of the coalitions, but often the number of coalition structures is too large to allow exhaustive search for the optimal one. But then, can the coalition structure found via a partial search be guaranteed to be within a bound from optimum?We show that none of the previous coalition structure generation algorithms can establish any bound because they search fewer nodes than a threshold that we show necessary for establishing a bound. We present an algorithm that establishes a tight bound within this minimal amount of search, and show that any other algorithm would have to search strictly more. The fraction of nodes needed to be searched approaches zero as the number of agents grows.If additional time remains, our anytime algorithm searches further, and establishes a progressively lower tight bound. Surprisingly, just searching one more node drops the bound in half. As desired, our algorithm lowers the bound rapidly early on, and exhibits diminishing returns to computation. It also drastically outperforms its obvious contenders. Finally, we show how to distribute the desired search across self-interested manipulative agents.
Comparing how atomicity mechanisms support replication

Most pessimistic mechanisms for implementing atomicity in distributed systems fall into three broad categories: two-phase locking schemes, timestamping schemes, and hybrid schemes employing both locking and timestamps. This paper proposes a new criterion for evaluating these mechanisms: the constraints they impose on the availability of replicated data.A replicated data item is a typed object that provides a set of operations to its clients. A quorum for an operation is any set of sites whose co-operation suffices to execute that operation, and a quorum assignment associates a set of quorums with each operation. Constraints on quorum assignment determine the range of availability properties realizable by a replication method.This paper compares the constraints on quorum assignment necessary to maximize concurrency under generalized locking, timestamping, and hybrid concurrency control mechanisms. This comparison shows that hybrid schemes impose weaker constraints on availability than timestamping schemes, and locking schemes impose constraints incomparable to those of the others. Because hybrid schemes permit more concurrency than locking schemes, these results suggest that hybrid schemes are preferable to the others for ensuring atomicity in highly available and highly concurrent distributed systems.This research was sponsored by the Defense Advanced Research Projects Agecy (DOD), ARPA Order No. 3597, monitored by the Air Force Avionics Laboratory Under Contract F33615-81-K-1539.The views and conclusions contained in this document are those of the authords and should not be interpreted as representing the official policies, either expressed or implied, of the Defense Advanced Research Projects Agency or the US Government.
THE U.S. WESTWARD EXPANSION

The U.S. economic development in the 19th century was characterized by the westward movement of population and the accumulation of productive land in the West. This article presents a model of migration and land improvement to identify the quantitatively important forces driving these phenomena. The conclusion is that the decrease in transportation costs induced the westward migration, whereas population growth was responsible for the investment in productive land.
An RF circuit model for carbon nanotubes

We develop an RF circuit model for single walled carbon nanotubes for both dc and capacitively contacted geometries. By modeling the nanotube as a nanotransmission line with distributed kinetic and magnetic inductance as well as distributed quantum and electrostatic capacitance, we calculate the complex, frequency dependent impedance for a variety of measurement geometries. Exciting voltage waves on the nanotransmission line is equivalent to directly exciting the yet-to-be observed one dimensional plasmons, the low energy excitation of a Luttinger liquid.
Model of Performance of a Regenerative Hydrogen Chlorine Fuel Cell for Grid-Scale Electrical Energy Storage

We develop a model for a regenerative hydrogen-chlorine fuel cell (rHCFC) including four voltage loss mechanisms: hydrogen electrode activation, chlorine electrode activation, chlorine electrode mass transport, and ohmic loss through the membrane. The dependences of each of these losses as a function of two “operating parameters,” acid concentration and temperature; and five “engineering parameters,” exchange current densities at both electrodes, membrane thickness, acid diffusion layer thickness, and cell pressure, are explored. By examining this large parameter space, we predict the design target and ultimate limitations to the performance characteristics of this cell. We identify chlorine electrode activation as the dominant contribution to the loss for low current density, high-efficiency operation and membrane resistance as the dominant contribution to the loss at maximum galvanic power density. We conclude that, with further research, a more optimal cell could be developed that operates at greater than 90% voltage efficiency at current densities >1 A
A dynamic evidential network for multisensor context reasoning in home-based care

In home-based care, reliable contextual information of remotely monitored patients should be generated to recognize activities and to identify hazardous situations of the patient. This is difficult for several reasons. First, low level data obtained from multisensor have different degrees of uncertainty. Second, generated contexts can be conflicting even if they are acquired by simultaneous operations. And last, context reasoning over time is difficult for temporal changes in sensory information. In this paper, we propose the dynamic evidential fusion approach as a context reasoning method in home-based care. The proposed approach processes the generated contexts with Dynamic Evidential Network (DEN), which is composed of the combination of Dezert-Smarandache Theory (DSmT) and Markov Chain (MC). The DSmT reduces ambiguous or conflicting contextual information and the MC processes the association and correlation of sensory information that may change based on time series. Finally, we compare the dynamic evidential fusion approach with the static evidential fusion approach for analyzing the improvement of the dynamic evidential fusion approach.
Shape discrimination using invariants defined from higher-order spectra

An approach to pattern recognition using invariant parameters based on higher-order spectra is presented. In particular, bispectral invariants are used to classify one-dimensional shapes. The bispectrum, which is translation invariant, is integrated along straight lines passing through the origin in bifrequency space. The phase of the integrated bispectrum is shown to be scale- and amplification-invariant. A minimal set of these invariants is selected as the feature vector for pattern classification. Pattern recognition using higher-order spectral invariants is fast, suited for parallel implementation, and works for signals corrupted by Gaussian noise. The classification technique is shown to distinguish two similar but different bolts given their one-dimensional profiles. >
AFFINE SEMIPRIME ALGEBRAS OF GK DIMENSION ONE ARE (STILL) PI

In this note, we give a new proof of the fact that an affine semiprime algebra $R$ of Gelfand-Kirillov dimension 1 satisfies a polynomial identity. Our proof uses only the growth properties of the algebra and yields an explicit upper bound for the pi degree of $R$ .
Development of a Fuzzy Logic Control System on a Freescale 68HCS12 Microcontroller for an Air Impingement Oven

The Stein Lab Oven is an air impingement oven used for research at the University of Arkansas on the elimination of pathogens such as Salmonella, Listeria monocytogenes and Escherichia coli from ready-to-eat beef and poultry products. This oven allows for control over cooking time, cooking temperature, humidity and airflow. During research the oven is operated at desired constant temperature, humidity and airflow values, but the temperature and humidity values deviate from the desired values when disturbances occur, such as when raw product is brought into the oven. A fuzzy logic control system is developed on a Freescale 68HCS12 microcontroller to maintain constant temperature and humidity values and quickly recover from disturbances to the oven. A model of the oven is developed in Matlab to facilitate the testing and verification of the fuzzy logic controller.
The Hubble constant.

Abstract Five methods of estimating distances have demonstrated internal reproducibility at the level of 5-20% rms accuracy. The best of these are the cepheid (and RR Lyrae), planetary nebulae, and surface-brightness fluctuation techniques. Luminosity-line width and Dn-sigma methods are less accurate for an individual case but can be applied to large numbers of galaxies. The agreement is excellent between these five procedures. It is determined that Hubble constant H0 = 90 +/- 10 km.s-1.Mpc-1 [1 parsec (pc) = 3.09 x 10(16) m]. It is difficult to reconcile this value with the preferred world model even in the low-density case. The standard model with Omega = 1 may be excluded unless there is something totally misunderstood about the foundation of the distance scale or the ages of stars.
Channels With Cost Constraints: Strong Converse and Dispersion

This paper shows the strong converse and the dispersion of memoryless channels with cost constraints and performs a refined analysis of the third-order term in the asymptotic expansion of the maximum achievable channel coding rate, showing that it is equal to $(1/ 2)(({\log n})/{n})$ in most cases of interest. The analysis is based on a nonasymptotic converse bound expressed in terms of the distribution of a random variable termed the $\mathsf b$ -tilted information density, which plays a role similar to that of the $\mathsf d$ -tilted information in lossy source coding. We also analyze the fundamental limits of lossy joint-source-channel coding over channels with cost constraints.
Discourse Obligations in Dialogue Processing

We show that in modeling social interaction, particularly dialogue, the attitude of obligation can be a useful adjunct to the popularly considered attitudes of belief, goal, and intention and their mutual and shared counterparts. In particular, we show how discourse obligations can be used to account in a natural manner for the connection between a question and its answer in dialogue and how obligations can be used along with other parts of the discourse context to extend the coverage of a dialogue system.
Advanced adaptive optics technology development

The NSF Center for Adaptive Optics (CfAO) is supporting research on advanced adaptive optics technologies. CfAO research activities include development and characterization of micro-electro-mechanical systems (MEMS) deformable mirror (DM) technology, as well as development and characterization of high-resolution adaptive optics systems using liquid crystal (LC) spatial light modulator (SLM) technology. This paper presents an overview of the CfAO advanced adaptive optics technology development activities including current status and future plans.
The Pursuit of Happiness: Time, Money, and Social Connection

Does thinking about time, rather than money, influence how effectively individuals pursue personal happiness? Laboratory and field experiments revealed that implicitly activating the construct of time motivates individuals to spend more time with friends and family and less time working—behaviors that are associated with greater happiness. In contrast, implicitly activating money motivates individuals to work more and socialize less, which (although productive) does not increase happiness. Implications for the relative roles of time versus money in the pursuit of happiness are discussed.
Physical Properties of Galaxies from z = 2–4

The epoch of galaxy assembly from 2⩽z⩽4 marks a critical stage during the evolution of today's galaxy population. During this period, the star-formation activity in the Universe was at its peak level, and the structural patterns observed among galaxies in the local Universe were not yet in place. A variety of novel techniques have been employed over the past decade to assemble multiwavelength observations of galaxies during this important epoch. In this primarily observational review, I present a census of the methods used to find distant galaxies and the empirical constraints on their multiwavelength luminosities and colors. I then discuss what is known about the stellar content and past histories of star formation in high-redshift galaxies; their interstellar contents including dust, gas, and heavy elements; and their structural and dynamical properties. I conclude by considering some of the most pressing and open questions regarding the physics of high-redshift galaxies, which are to be addressed with ...
The Bethe permanent of a non-negative matrix

It has recently been observed that the permanent of a non-negative matrix, i.e., of a matrix containing only non-negative real entries, can very well be approximated by solving a certain Bethe free energy minimization problem with the help of the sum-product algorithm. We call the resulting approximation of the permanent the Bethe permanent.
Soluble selenides and tellurides

Caracterisation structurale de complexes metalliques telluro et seleno. Reactivite chimique; synthese bibliographique
Probabilistic reasoning with answer sets

This paper develops a declarative language, P-log, that combines logical and probabilistic arguments in its reasoning. Answer Set Prolog is used as the logical foundation, while causal Bayes nets serve as a probabilistic foundation. We give several non-trivial examples and illustrate the use of P-log for knowledge representation and updating of knowledge. We argue that our approach to updates is more appealing than existing approaches. We give sufficiency conditions for the coherency of P-log programs and show that Bayes nets can be easily mapped to coherent P-log programs.
Target Assignment in Robotic Networks: Distance Optimality Guarantees and Hierarchical Strategies

We study the problem of multi-robot target assignment to minimize the total distance traveled by the robots until they all reach an equal number of static targets. In the first half of the paper, we present a necessary and sufficient condition under which true distance optimality can be achieved for robots with limited communication and target-sensing ranges. Moreover, we provide an explicit, non-asymptotic formula for computing the number of robots needed to achieve distance optimality in terms of the robots' communication and target-sensing ranges with arbitrary guaranteed probabilities. The same bounds are also shown to be asymptotically tight. In the second half of the paper, we present suboptimal strategies for use when the number of robots cannot be chosen freely. Assuming first that all targets are known to all robots, we employ a hierarchical communication model in which robots communicate only with other robots in the same partitioned region. This hierarchical communication model leads to constant approximations of true distance-optimal solutions under mild assumptions. We then revisit the limited communication and sensing models. By combining simple rendezvous-based strategies with a hierarchical communication model, we obtain decentralized hierarchical strategies that achieve constant approximation ratios with respect to true distance optimality. Results of simulation show that the approximation ratio is as low as 1.4.
The voluntary provision of a pure public good and the Montreal Protocol: behavioral and data concerns

This article argues that the World Resources Institute (WRI) data are appropriate for our game-theoretic-based analysis of countries’ CFC emission cutbacks prior to the ratification of the Protocol. Given the underlying game from which our reduced-form equations follow, the policymakers must be viewed as responding to contemporary information, which was the WRI dataset. The article also addresses the issue of an alleged perfect correlation being induced between CFC emission cutbacks and GNP due to the imputation process used by WRI. The article also raises concerns about inventory inclusion in the United Nations Environmental Programme data that could distort cutbacks for major producer countries that were likely to stockpile CFCs before production lines were shifted over to CFC substitutes.
Position Sensing by Charge Division

A summary of a comprehensive analysis of theoretical and practical aspects of position sensing by charge division from resistive electrodes is presented. Properties of transformer decoupling of the resistive electrode from detection bias voltage are analyzed and compared to the usual capacitive decoupling methods. Optimization and limitation of signal shaping is discussed as a function of diffusion time constant, signal rise times, and noise.