cssi/SciSciGPT-SciSciNet huggingface dataset:
MobiWorp: Mitigation of the wormhole attack in mobile multihop wireless networks

In multihop wireless systems, the need for cooperation among nodes to relay each other's packets exposes them to a wide range of security attacks. A particularly devastating attack is the wormhole attack, where a malicious node records control traffic at one location and tunnels it to a colluding node, possibly far away, which replays it locally. This can have an adverse effect on route establishment by preventing nodes from discovering legitimate routes that are more than two hops away. Previous works on tolerating wormhole attacks have focused only on detection and used specialized hardware, such as directional antennas or extremely accurate clocks. More recent work has addressed the problem of locally isolating the malicious nodes. However, all of this work has been done in the context of static networks due to the difficulty of secure neighbor discovery with mobile nodes. The existing work on secure neighbor discovery has limitations in accuracy, resource requirements, and applicability to ad hoc and sensor networks. In this paper, we present a countermeasure for the wormhole attack, called MobiWorp, which alleviates these drawbacks and efficiently mitigates the wormhole attack in mobile networks. MobiWorp uses a secure central authority (CA) for global tracking of node positions. Local monitoring is used to detect and isolate malicious nodes locally. Additionally, when sufficient suspicion builds up at the CA, it enforces a global isolation of the malicious node from the whole network. The effect of MobiWorp on the data traffic and the fidelity of detection is brought out through extensive simulation using ns-2. The results show that as time progresses, the data packet drop ratio goes to zero with MobiWorp due the capability of MobiWorp to detect, diagnose and isolate malicious nodes. With an appropriate choice of design parameters, MobiWorp is shown to completely eliminate framing of a legitimate node by malicious nodes, at the cost of a slight increase in the drop ratio. The results also show that increasing mobility of the nodes degrades the performance of MobiWorp.
Photophysics of metal-organic π-conjugated polymers

Abstract A series of polyaryleneethynylene π-conjugated polymers that contain fac -(5,5′-diethynyl-2,2′-bipyridine)Re I (CO) 3 Cl as part of the π-conjugated polymer backbone have been synthesized by Pd-mediated coupling chemistry. Three metal-organic polymers P10, P25 and P50 , have been prepared which contain, respectively, 10, 25 and 50 mol.% of the Re(I) repeat units in the polymer chain. These polymers have been characterized by 1 H- and 13 C-NMR and FTIR spectroscopy and gel permeation chromatography. The analysis indicate that the pholymers contain the intact Re(I) chromophore and M n values of 10–15 kDa are typical (GPC, relative to polystyrene). The metal-organic polymers feature two spectrally-distinct absorption bands, one due to the π, π ∗ absorption of the polymer backbone and another at lower energy which is attributed to the d π( Re )→π poly ∗ metal to ligand charge transfer (MLCT) absorption. The luminescence properties of the polymers have been examined in fluid solution at 298 K and in a 2-methyltetrahedrofuran (MTHF) solvent glass at 77 K. These spectroscopic studies reveal that: (1) fluorescence from the 1 π, π ∗ exciton state is observed at 2.80 eV in all of the polymers at 298 and 77 K, but the intensity and lifetime of the fluorescence is quenched as the mole fraction of Re in the polymers increases; (2) phosphorescence from the 3 π, π ∗ state of the conjugated polymer backbone is observed at 1.93 eV in P10–P50 at 77 K; (3) luminescence from the d π→π ∗ MLCT state is observed at 1.8 eV in the metal-organic polymers at 77 K.
Employee participation in management, bargaining power and wages

The paper analyzes the impact of employee participation in management on bargaining power and wages. It presents an empirical model which allows for variable bargaining powers of the parties who jointly control the firm and it tests this model with postwar West German data. The results suggest that ‘parity codetermination’ has had a positive effect on earnings in iron and steel but not in coal mining. Moreover, it appears that the positive effect in iron and steel could be due to increased profitability rather than an increase in the bargaining power of labor as defined in this study.
Network management game

Management and automated configuration of large-scale networks is one of the crucial issues for Internet Service Providers (ISPs). Since wrong configurations may lead to loss of an enormous amount of customer traffic, highly experienced network administrators are typically the ones who are trusted for the management and configuration of a running ISP network. We frame the management and experimentation of a network as a "game" for training network administrators without having to risk the network operation. The interactive environment treats the trainee network administrators as players of a game and tests them with various network failures or dynamics.
Affinely invariant matching methods with discriminant mixtures of proportional ellipsoidally symmetric distributions

In observational studies designed to estimate the effects of interventions or exposures, such as cigarette smoking, it is desirable to try to control background differences between the treated group (e.g., current smokers) and the control group (e.g., never smokers) on covariates X (e.g., age, education). Matched sampling attempts to effect this control by selecting subsets of the treated and control groups with similar distributions of such covariates. This paper examines the consequences of matching using affinely invariant methods when the covariate distributions are "discriminant mixtures of proportional ellipsoidally symmetric" (DMPES) distributions, a class herein defined, which generalizes the ellipsoidal symmetry class of Rubin and Thomas [Ann. Statist. 20 (1992) 1079-1093]. The resulting generalized results help indicate why earlier results hold quite well even when the simple assumption of ellipsoidal symmetry is not met [e.g., Biometrics 52 (1996) 249-264]. Extensions to conditionally affinely invariant matching with conditionally DMPES distributions are also discussed.
Effect of acute and chronic ethanol on the agonist responses of vascular smooth muscle.

Abstract We studied the effect of ethanol in vitro on the response of isolated rat aortas to phenylephrine and angiotensin II. We also examined the effect of chronic ethanol consumption on the phenylephrine response and the effect of ethanol in vitro on that response during the development of ethanol-induced hypertension. In acute experiments the depression of the phenylephrine dose-response produced by ethanol in vitro was greater than that for angiotensin II. Comparing the depression of these agonist dose-responses by ethanol to the depression by the receptor blockers, verapamil, prazosin and saralasin, suggests that ethanol may act like an α1-adrenoceptor blocker. During chronic ethanol consumption two opposing changes occurred: (1) desensitization to phenylephrine during weeks 6–18 and, (2) tolerance to depression by ethanol in vitro during weeks 4–10. These opposing changes may cancel each other which suggests that the hypertension due to chronic ethanol consumption is probably not due to an action of ethanol on the vasculature.
A simple program to train case managers in community elderly care

The case manager, like many “new professions” does not yet have a defined curriculum. We consider that the principal requisite for case managers is a proficient knowledge of assessment for the care of the elderly. Therefore, we focused a four-week teaching course for future case managers on the National Resident Assessment Instrument (RAI) of the United States and the Long-Term Care Program Application and Admission Form of British Columbia, Canada. We verified that this simple program provides students with adequate skills to become case managers.
Multidimensional Poverty: Measurement, Estimation, and Inference

Multidimensional poverty measures give rise to a host of statistical hypotheses which are of interest to applied economists and policy-makers alike. In the specific context of the generalized Alkire-Foster (Alkire and Foster 2008) class of measures, we show that many of these hypotheses can be treated in a unified manner and also tested simultaneously using the minimum p-value methodology of Bennett (2010). When applied to study the relative state of poverty among Hindus and Muslims in India, these tests reveal novel insights into the plight of the poor which are not otherwise captured by traditional univariate approaches.
Spatial Hedonic Analysis of the Effects of US Wind Energy Facilities on Surrounding Property Values

Rapid, large-scale U.S. deployment of wind turbines is expected to continue in the coming years. Because some of that deployment is expected to occur in relatively populous areas, concerns have arisen about the impact of turbines on nearby home values. Previous research on the effects of wind turbines on surrounding home values has been limited by small home-sale data samples and insufficient consideration of confounding home-value factors and spatial dependence. This study examines the largest set of turbine-proximal sales data to date: more than 50,000 home sales including 1,198 within 1 mile of a turbine (331 of which were within a half mile). The data span the periods well before announcement of the wind facilities to well after their construction. We use ordinary least squares and spatial-process difference-in-difference hedonic models to estimate the home-value impacts of the wind facilities, controlling for value factors existing prior to the wind facilities’ announcements, the spatial dependence of home values, and value changes over time. A series of robustness models provide greater confidence in the results. We find no statistical evidence that home values near turbines were affected in the turbine post-construction or post-announcement/pre-construction periods.
LENGTH SPECTRA OF NATURAL NUMBERS

A natural number n can generally be written as a sum of m consecutive natural numbers for various values of m ≥ 1. The length spectrum of n is the set of these admissible m. Two numbers are spectral equivalent if they have the same length spectrum. We show how to compute the equivalence classes of this relation. Moreover, we show that these classes can only have either 1,2 or infinitely many elements.
A new approach to Cholesky-based covariance regularization in high dimensions

SUMMARY In this paper we propose a new regression interpretation of the Cholesky factor of the covariance matrix, as opposed to the well-known regression interpretation of the Cholesky factor of the inverse covariance, which leads to a new class of regularized covariance estimators suitable for high-dimensional problems. Regularizing the Cholesky factor of the covariance via this regression interpretation always results in a positive definite estimator. In particular, one can obtain a positive definite banded estimator of the covariance matrix at the same computational cost as the popular banded estimator of Bickel & Levina (2008b), which is not guaranteed to be positive definite. We also establish theoretical connections between banding Cholesky factors of the covariance matrix and its inverse and constrained maximum likelihood estimation under the banding constraint, and compare the numerical performance of several methods in simulations and on a sonar data example.
Microbial degradation of lignin

Abstract The transformations of lignin that occur during its biodegradation are complex and incompletely understood. Certain fungi of the white-rot group, and possibly other fungi and bacteria, completely decompose lignin to carbon dioxide and water. Other fungi and bacteria apparently degrade lignin incompletely. Differences in lignin-degrading abilities observed for different organisms may result from differences in the completeness of their ligninolytic enzyme systems. Not all lignin components may be attacked by a particular organism. Alternatively, different organisms may differ in their basic mechanisms of attack on lignin. The basic pathways of lignin degradation have been elucidated only for certain representatives of the white-and brown-rot fungi. Although it is known that each of the principal structural components of lignin is attacked by other fungi and bacteria, the biochemistry of that attack has not been elucidated. Work with low molecular weight lignin models has provided only limited information on possible pathways of lignin degradation by microorganisms. There is little evidence to suggest a correlation between abilities to degrade single-ring aromatic or lignin model compounds and the ability to degrade polymeric lignin. More evidence has come from analysis of spent culture media for lignin breakdown products and from comparative chemical analyses of sound lignins versus decayed lignin residues. Accumulated evidence with the most thoroughly studied white-rot fungi suggests that with these fungi lignin degradation proceeds by way of extracellular mixed-function oxygenases and dioxygenases, which catalyse demethylations, hydroxylations and ring-fission reactions within a largely intact polymer, concomitant with some release of low molecular weight lignin fragments. There are also apparent relationships between lignin, carbohydrate and nitrogen metabolism for some organisms, but the relationships may vary from one organism to another. Although research is now mostly at a basic level, industrial applications may result from lignin degradation research. Considerable potential exists for the development of bioconversions which might produce low molecular weight chemicals from waste lignins, and thereby reduce our dependence on petroleum as a source of these chemicals. Alternatively, such bioconversions might produce chemically altered forms of polymeric lignin that may be valuable industrially.
A theoretical study of nonlinear combustion instability in liquid-propellant rocket engines.

Nonlinear combustion instability in liquid propellant rocket engines, describing nonsteady combustion process with aid of Crocco time lag hypothesis
Galerkin eigenvector approximations

How close are Galerkin eigenvectors to the best approximation available out of the trial subspace? Under a variety of conditions the Galerkin method gives an approximate eigenvector that approaches asymptotically the projection of the exact eigenvector onto the trial subspace-and this occurs more rapidly than the underlying rate of convergence of the approximate eigenvectors. Both orthogonal-Galerkin and Petrov-Galerkin methods are considered here with a special emphasis on nonselfadjoint problems, thus extending earlier studies by Chatelin, Babuska and Osborn, and Knyazev. Consequences for the numerical treatment of elliptic PDEs discretized either with finite element methods or with spectral methods are discussed. New lower bounds to the sep of a pair of operators are developed as well.
Twisted and Nontwisted Bifurcations Induced by Diffusion

We discuss a diffusively perturbed predator-prey system. Freedman and Wolkowicz showed that the corresponding ODE can have a periodic solution that bifurcates from a homoclinic loop. When the diffusion coefficients are large, this solution represents a stable, spatially homogeneous time-periodic solution of the PDE. We show that when the diffusion coefficients become small, the spatially homogeneous periodic solution becomes unstable and bifurcates into spatially nonhomogeneous periodic solutions. The nature of the bifurcation is determined by the twistedness of an equilibrium/homoclinic bifurcation that occurs as the diffusion coefficients decrease. In the nontwisted case two spatially nonhomogeneous simple periodic solutions of equal period are generated, while in the twisted case a unique spatially nonhomogeneous double periodic solution is generated through period-doubling.
Constrained walks and self-avoiding walks: implications for protein structure determination

We prove that n-step walks and self-avoiding walks on the 2D honeycomb, 2D square, 3D diamond and 3D cubic lattices can be uniquely characterized (canonized) with no more than n Euclidian distances. We also demonstrate that these canonical distances can be obtained with O(n) physical measurements. Finally, while the protein-folding problem on lattices is known to be strongly NP-hard, we prove that lattice protein structures of size n matching O(n) canonical distance measurements can be determined in linear time.
Anisotropic magnetohydrodynamic turbulence in a strong external magnetic field

A strong external dc magnetic field introduces a basic anisotropy into incompressible magnetohydrodynamic turbulence. The modifications that this is likely to produce in the properties of the turbulence are explored for the high Reynolds number case. The conclusion is reached that the turbulent spectrum splits into two parts: an essentially two dimensional spectrum with both the velocity field and magnetic fluctuations perpendicular to the dc magnetic field, and a generally weaker and more nearly isotropic spectrum of Alfven waves. A minimal characterization of the spectral density tensors is given. Similarities to measurements from the Culham-Harwell Zeta pinch device and the UCLA Macrotor Tokamak are remarked upon, as are certain implications for the Belcher and Davis measurements of magnetohydrodynamic turbulence in the solar wind.
Bright Supernovae from Magnetar Birth

Following an initial explosion that might be launched either by magnetic interactions or neutrinos, a rotating magnetar radiating according to the classic dipole formula could power a very luminous supernova. While some 56Ni might be produced in the initial explosion, the peak of the light curve in a Type I supernova would not be directly related to its mass. In fact, the peak luminosity would be most sensitive to the dipole field strength of the magnetar. The tail of the light curve could resemble radioactive decay for some time but, assuming complete trapping of the pulsar emission, would eventually be brighter. Depending on the initial explosion energy, both high and moderate velocities could accompany a very luminous light curve.
A Test Program for the Evaluation of Oilfield Thread Protectors

Transportation, handling, and corrosion damage to the threads of oilfield tubulars cost the industry millions of dollars each year. This problem has intensified with the increased use of proprietary connections, which represent a significant percentage of the total tubular cost. The thread protector is the primary means of protecting the threads from impact and corrosion damage. A test program has been designed and a test facility built. To evaluate the performance of oilfield protectors, a wide variety of thread protectors were tested, including metal, plastic, and composite (metal-elastomer) designs. This paper discusses this testing and outlines a guide for the selection of oilfield thread protectors for various service conditions.
IBM 7070 data processing system

In 1953, International Business Machines Corporation (IBM) introduced its first production model of a large-scale computer---the IBM 701 Data Processing Machine. Since that time, the company has engineered and delivered a number of major data processing systems, each designed to meet certain business and scientific requirements.
Real-Time Selective Harmonic Minimization for Multilevel Inverters Connected to Solar Panels Using Artificial Neural Network Angle Generation

This work approximates the selective harmonic elimination problem using artificial neural networks (ANNs) to generate the switching angles in an 11-level full-bridge cascade inverter powered by five varying dc input sources. Each of the five full bridges of the cascade inverter was connected to a separate 195-W solar panel. The angles were chosen such that the fundamental was kept constant and the low-order harmonics were minimized or eliminated. A nondeterministic method is used to solve the system for the angles and to obtain the data set for the ANN training. The method also provides a set of acceptable solutions in the space where solutions do not exist by analytical methods. The trained ANN is a suitable tool that brings a small generalization effect on the angles' precision and is able to perform in real time (50-/60-Hz time window).
Rearrangement of N,N-Di-tert-butoxycarbonylpyridin-4-amines and Formation of Polyfunctional Pyridines

N,N-Di-tert-butoxycarbonylpyridin-4-amines were found to be rearranged to tert-butyl 4-(tert-butoxycarbonylamino)nicotinates by treatment with LDA in THF.
Rehabilitation following bone marrow transplantation

Bone marrow transplantation and stem cell transplantation are increasingly used to treat hematologic malignancies and some solid tumors. The treatment entails bone marrow-ablative therapies and intensive medical support to sustain the patient through pancytopenia and other complications of the disease, transplantation process, or drug side effects. Patients who develop graft-versus-host disease are the most difficult subset of transplant recipients to manage. Most transplant recipients perform at normal or near-normal functional levels at the inception of the transplantation process but are at high risk for developing functional deficits as a result of cumulative impairments. These impairments arise from their disease, their prior cancer treatment, transplant induction, graft-versus-host disease, immobility, infection, steroid-related side effects, and other sequelae of transplantation. Preventive and preemptive rehabilitation interventions can minimize functional loss and facilitate recovery, but the transplantation team must be sensitive to and regularly assess for early functional declines in these patients. The physiatrist and the other members of the rehabilitation team must be thoroughly acquainted with the unique needs and challenges of the bone marrow transplantation population in order to design and modify treatment programs effectively and safely. Outcome research has shown that some patients have continued limitations in function despite successful transplantation. Few evidence-based data are available that addresses factors correlating with poor functional outcomes other than graft-versus-host disease. However, this disease has not been investigated utilizing objective functional instruments. Future research should more clearly elucidate the functional impact of allogeneic and autologous transplants by using standardized physical performance measures as well as thorough function-based symptomatology questionnaires.
CONNECTING THE GAMMA RAY BURST RATE AND THE COSMIC STAR FORMATION HISTORY: IMPLICATIONS FOR REIONIZATION AND GALAXY EVOLUTION

The contemporary discoveries of galaxies and gamma ray bursts (GRBs) at high redshift have supplied the first direct information on star formation when the universe was only a few hundred million years old. The probable origin of long duration GRBs in the deaths of massive stars would link the universal GRB rate to the redshift-dependent star formation rate (SFR) density, although exactly how is currently unknown. As the most distant GRBs and star-forming galaxies probe the reionization epoch, the potential reward of understanding the redshift-dependent ratio Ψ(z) of the GRB rate to SFR is significant and includes addressing fundamental questions such as incompleteness in rest-frame UV surveys for determining the SFR at high redshift and time variations in the stellar initial mass function. Using an extensive sample of 112 GRBs above a fixed luminosity limit drawn from the Second Swift Burst Alert Telescope catalog and accounting for uncertainty in their redshift distribution by considering the contribution of "dark" GRBs, we compare the cumulative redshift distribution N( 4 measured from rest-frame optical surveys. The resolution of this important disagreement is currently unclear, and the GRB production rate at early times is likely more complex than a simple function of SFR and progenitor metallicity.
The Secondary Amine/Nitric Oxide Complex Ion R2N[N(O)NO]- as Nucleophile and Leaving Group in SNAr Reactions

Ions of structure R2N[N(O)NO]- and their alkylation products have seen increasing use as nitric oxide (NO)-generating agents for biomedical research applications. Here we show that such diazeniumdiolate anions can readily displace halide from a variety of electrophilic aza- or nitroaromatic substrates to form O2-arylated derivatives of structure R2N−N(O)N−OAr. The site of arylation and the cis arrangement of the oxygens were confirmed by X-ray crystallography. Displacement by various nucleophiles showed R2N[N(O)NO]- to be a reasonably good leaving group, with rate constants for displacement by hydroxide, methoxide, and isopropylamine that were between those of chloride and fluoride in the SNAr reactions we surveyed. The Meisenheimer intermediate could be spectrally observed. These O2-aryl diazeniumdiolates proved capable of reacting with the nucleophilic sulfur of the HIV-1 p7 nucleocapsid protein's zinc finger assembly to eject the zinc, disrupting a structural motif critical to viral replication and sug...
Balmer and Metal Absorption Feature Gradients in M32

New data sources are used to assess Lick/IDS feature strength gradients inside the half-light radius Re of the compact Local Group elliptical galaxy M32. A Hubble Space Telescope (HST) STIS spectrum seemed to indicate ionized gas and a very young central stellar population. In fact, this conclusion is entirely spurious because of incomplete removal of ion hits. More robust ground-based spectra taken at the MDM Observatory are, in contrast, the most accurate measurements of Lick/IDS indices yet obtained for M32. All but a few (of 24 measured) indices show a statistically significant gradient. The CN indices show a maximum at 4'' radius, dropping off both toward the nucleus and away from it. At 2'' radius there is a discontinuity in the surface brightness profile, but this feature is not reflected in any spectral feature. Comparing with models, the index gradients indicate a mean age and abundance gradient in the sense that the nucleus is a factor of 2.5 younger and a factor of 0.3 dex more metal-rich than at 1Re. This conclusion is only weakly dependent on which index combinations are used and is robust to high accuracy. Stars near the M32 nucleus have a mean age and heavy element abundance [M/H] of (4.7 Gyr, +0.02), judging from models by Worthey with variable abundance ratios. This result has very small formal random errors, although, of course, there is significant age-metallicity degeneracy along an (age, abundance) line segment from (5.0 Gyr, 0.00) to (4.5 Gyr, +0.05). An abundance pattern of [C/M] = +0.077 (carbon abundance affects CN, C24668, and the bluer Balmer features), [N/M] = -0.13, [Mg/M] = -0.18, [Fe/M] ≈ 0.0, and [Na/M] = +0.12 is required to fit the feature data, with a fitting precision of about 0.01 dex (with two caveats: the [Fe/M] guess has about twice this precision because of the relative insensitivity of the Fe5335 feature to iron, and the [Na/M] value may be falsely amplified because of interstellar absorption). Model uncertainties make the accuracies of these values at least twice the magnitude of the precision. Forcing scaled-solar abundances does not change the age very much, but it increases the rms goodness of model-data fit by a factor of 3 and broadens the allowed range of age to ±1 Gyr. The abundance ratios do not show strong trends with radius, except for the nuclear weakening of CN (measuring mainly N) mentioned above, which needs reconfirming with better data. The overall abundance pattern contrasts with larger elliptical galaxies, in which all measurable lighter elements are enhanced relative to iron and calcium. Nucleosynthetic theory does not provide a ready explanation for these mixtures.
A Catalog of Planetary Nebulae in the Elliptical Galaxy NGC 4697

We present a catalog of 535 planetary nebulae (PNs) discovered in the flattened elliptical galaxy NGC 4697, using the FORS1 Cassegrain spectrograph of the Very Large Telescope of the European Southern Observatory at Cerro Paranal, Chile. The catalog provides positions [(x,y)-coordinates relative to the center of light of NGC 4697, as well as α,δ] and, for almost all PNs, the magnitude m(5007) and the heliocentric radial velocity in km s−1.
Fibrations of Simplicial Sets

There are infinitely many variants of the notion of Kan fibration that, together with suitable choices of cofibrations and the usual notion of weak equivalence of simplicial sets, satisfy Quillen’s axioms for a homotopy model category. The combinatorics underlying these fibrations is purely finitary and seems interesting both for its own sake and for its interaction with homotopy types. To show that these notions of fibration are indeed distinct, one needs to understand how iterates of Kan’s Ex functor act on graphs and on nerves of small categories.
EUVL contamination control studies for high volume manufacturing

This paper describes the research done at center for plasma material interactions (CPMI) to address the EUVL (extreme ultra- violet lithography) contamination control to achieve the HVM (high volume manufacturing) requirements in industry. Energetic atom and macro-particle emission are unavoidable when plasmas are used to generate photons in both DPP and LPP based EUV sources. These emitted particles interact first with the collection optics for the EUV radiation. Then some of the low energy sputtered collector material and some of the condensable Sn fuel exit at the intermediate focus (IF). This is undesirable. A critical requirement of stepper manufactures is to have only clean photons at the IF of EUV source-collector module. The very EUV photons that the system is designed to create can have an effect on the projection and illumination optics causing a reduction of mirror reflectivity. Even with advanced mitigation techniques, stepper optics can be damaged due to energetic and thermal neutrals. Particle contamination is problematic at the mask, and resist issues on the wafers themselves have an effect on the masks and optic elements. The efficiency of mitigation schemes is discussed. We present progress on our recent experiments on the measurement of ionic and neutral debris at Intermediate Focus (IF) in the DPP source. We also present progress on cleaning Sn deposition off of a multi-shell collector mock-up using reactive ion etching plasma, particle contamination removal from the mask blanks, and line edge roughness reduction in photoresisit.
Stochastic global optimization as a filtering problem

We present a reformulation of stochastic global optimization as a filtering problem. The motivation behind this reformulation comes from the fact that for many optimization problems we cannot evaluate exactly the objective function to be optimized. Similarly, we may not be able to evaluate exactly the functions involved in iterative optimization algorithms. For example, we may only have access to noisy measurements of the functions or statistical estimates provided through Monte Carlo sampling. This makes iterative optimization algorithms behave like stochastic maps. Naive global optimization amounts to evolving a collection of realizations of this stochastic map and picking the realization with the best properties. This motivates the use of filtering techniques to allow focusing on realizations that are more promising than others. In particular, we present a filtering reformulation of global optimization in terms of a special case of sequential importance sampling methods called particle filters. The increasing popularity of particle filters is based on the simplicity of their implementation and their flexibility. We utilize the flexibility of particle filters to construct a stochastic global optimization algorithm which can converge to the optimal solution appreciably faster than naive global optimization. Several examples of parametric exponential density estimation are provided to demonstrate the efficiency of the approach.
New Tests of Magnetospheric Accretion in T Tauri Stars

We examine three analytic theories of magnetospheric accretion onto classical T Tauri stars (CTTSs) under the assumption that the magnetic field strength does not vary appreciably from star to star. From these investigations we derive predicted relationships among the stellar mass, radius, rotation period, and disk accretion rate. Data from five studies of the accretion parameters of CTTSs are used to test the predicted correlations. We generally find that the data do not display the predicted correlations except for that predicted by the model of Shu et al. as detailed by Ostriker & Shu and extended here to include nondipole field topologies. Their identification of the trapped flux as an important quantity in the model appears to be critical for reconciling the observed data to the theory. While the data do generally support the extended Ostriker & Shu predictions, only one of the two studies for which the requisite data exist shows the highest correlation when considering all the relevant parameters. This suggests that great care must be taken when trying to use existing observations to test the theory.
Holographic algorithms: From art to science

We develop the theory of holographic algorithms initiated by Leslie Valiant. First we define a basis manifold. Then we characterize algebraic varieties of realizable symmetric generators and recognizers on the basis manifold, and give a polynomial time decision algorithm for the simultaneous realizability problem. These results enable one to decide whether suitable signatures for a holographic algorithm are realizable, and if so, to find a suitable linear basis to realize these signatures by an efficient algorithm. Using the general machinery we are able to give unexpected holographic algorithms for some counting problems, modulo certain Mersenne type integers. These counting problems are #P-complete without the moduli. Going beyond symmetric signatures, we define d-admissibility and d-realizability for general signatures, and give a characterization of 2-admissibility and some general constructions of admissible and realizable families.
Integrable N = 2 Landau-Ginzburg theories from quotients of fusion rings☆

Abstract The discovery of integrable N = 2 supersymmetric Landau-Ginzburg theories whose chiral rings are fusion rings suggests a close connection between fusion rings, the related Landau-Ginzburg superpotentials, and N = 2 quantum integrability. We examine this connection by finding the natural SO( N ) K analogue of the construction that produced the superpotentials with Sp( N ) K and SU( N ) K fusion rings as chiral rings. The chiral rings of the new superpotentials are not directly the fusion rings of any conformal field theory, although they are natural quotients of the tensor subring of the SO( N ) K fusion ring. The new superpotentials yield solvable (twisted N = 2) topological field theories. We obtain the integer-valued correlation functions as sums of SO( N ) K Verlinde dimensions by expressing the correlators as fusion residues. The SO(2 n + 1) 2 k + 1 and SO(2 k + 1) 2 n + 1 related topological Landau-Ginzburg theories are isomorphic, despite being defined via quite different superpotentials.
Schottky barriers at metal-finite semiconducting carbon nanotube interfaces

Electronic properties of metal-finite semiconducting carbon nanotube interfaces are studied as a function of the nanotube length using a self-consistent tight-binding theory. We find that the shape of the potential barrier depends on the long-range tail of the charge transfer, leading to an injection barrier thickness comparable to half of the nanotube length until the nanotube reaches the bulk limit. The conductance of the nanotube junction shows a transition from tunneling to thermally activated transport with increasing nanotube length.
On the Redshift Distribution of Gamma-Ray Bursts in the Swift Era

A simple physical model for long-duration gamma-ray bursts (GRBs) is used to fit the redshift (z) and the jet opening angle distributions measured with earlier GRB missions and with Swift. The effect of different sensitivities for GRB triggering is sufficient to explain the difference in the z distributions of the pre-Swift and Swift samples, with mean redshifts of z 1.5 and z 2.7, respectively. Assuming that the emission properties of GRBs do not change with time, we find that the data can only be fitted if the comoving rate density of GRB sources exhibits positive evolution to z 3-5. The mean intrinsic beaming factor of GRBs is found to range from ?34 to 42, with the Swift average opening half-angle ?j ~ 10?, compared to the pre-Swift average of ?j ~ 7?. Within the uniform jet model, the GRB luminosity function is L, as inferred from our best fit to the opening angle distribution. Because of the unlikely detection of several GRBs with z 0.25, our analysis indicates that low-redshift GRBs represent a different population of GRBs than those detected at higher redshifts. Neglecting possible metallicity effects on GRB host galaxies, we find that ?1 GRB occurs every 600,000 yr in a local L* spiral galaxy like the Milky Way. The fraction of high-redshift GRBs is estimated at 8%-12% and 2.5%-6% at z ? 5 and z ? 7, respectively, assuming continued positive evolution of the GRB rate density to high redshifts.
Nonlinear motion of a missile with slight configurational asymmetries

The quasi-linear analysis which has been successfully applied to the nonlinear angular motion of symmetric missiles is extended to include the nonlinear motion of slightly asymmetric missiles. This analysis indicates the existence of three special spin rates—'zero spin, resonant spin, and approximately three times resonant spin. The exact solution for the small amplitude motion about a large trim angle of a nonspinning missile with a cubic static moment is obtained and the quasi-linear relations are shown to agree well with this exact result. Relations for a cubic damping moment and a cubic lift force are derived.
The Importance of the Electoral Rule: Evidence from Italy

Abstract We test the effect of an important electoral reform implemented in Italy from 1993 to 2001, that moved the system for electing the Parliament from purely proportional to a plurality rule (for 75% of the seats). We do not find any effect on either the number of parties or the stability of governments (the two main objectives of the reform) that remained unchanged at their pre-reform level.
Kinetics modeling of plasma exchange: Intra- and post-plasma exchange

Patient response to plasma exchange is variable. Clinical experience indicates that the outcome depends on the size of the exchange relative to the patient's plasma volume, the amount of material available for removal in both the intravascular and extravascular pools, and the mobility of the material between the pools. Post-exchange, the patient's course also depends on the mobility of the material between the pools as well as its production and catabolic rates. The work reported here is an attempt to construct a mathematical model that describes events occurring intra- and post-plasma exchange. An attempt to model the kinetics of plasma exchange promotes an understanding of the requirements of volume removal in individual exchange procedures for optimal results, and establishes the interval between exchanges required to sustain the response to each individual exchange procedure.
Alfvén‐cyclotron scattering of solar wind ions: Hybrid simulations

[1] This paper describes results from ensembles of hybrid simulations of steady, homogeneous, collisionless plasmas characterized by average solar wind parameters near 1 AU upon which damped, resonant Alfven-cyclotron fluctuations are imposed. The applied fluctuations propagate parallel to the background magnetic field B o . The ensembles yield late-time proton and alpha particle responses to such fluctuations as functions of the initial magnitude of the applied fluctuating magnetic field energy and the initial ν αp /ν A (where ν αp is the alpha/proton relative speed and ν A is the Alfven speed). The simulations show a strong, consistent negative correlation between the alpha temperature anisotropy T? α /T ∥α (where the directional subscripts refer to directions perpendicular and parallel to By) and ν αp /ν A . On average the simulations also show a weaker, positive correlation between the proton temperature anisotropy and ν αp /ν A . Both correlations are in agreement with statistical observations from the solar wind near 1 AU, thereby confirming earlier conclusions that such observations are signatures of Alfvencyclotron scattering of ions in the solar wind.
Non-aqueous phase liquid drop formation within a water saturated fracture

This work focuses on the mechanisms of non-aqueous phase liquid (NAPL) drop formation within a single fracture fed from a NAPL reservoir by way of a circular orifice, such as a pore. The fracture is assumed to be fully saturated, the relative wettability of the system is assumed water-wet, and the water velocity profile within the fracture is described by a Poiseuille flow. The size of the NAPL drops is investigated for various water flow velocities and NAPL entrance diameters. A force balancing method was used to determine the radii of detached drops. The drop sizes calculated from the model developed here are shown to be in agreement with available experimental drop size data. It is shown that at low Reynolds numbers the buoyancy force is the dominant force acting on the drop during the formation process and at high Reynolds numbers the viscous forces dominate. A simplified expression relating the geometry of the fractured system to the drop radii is developed from the model equations, and it is shown to predict drop radii that match well with both the model simulations and the available experimental data.
Membrane Micro Air Vehicles with Adaptive Aerodynamic Twist: Numerical Modeling

Micro air vehicles are typically characterized by a low aspect ratio wing operating at low Reynolds numbers ( 104 ) : aerodynamics involve a three-dimensional flow field with numerous regions of separated flow. Furthermore, aerodynamic twist can be built into the wing through the use of a thin membrane skin, to adaptively increase the wing camber. This work formulates a static aeroelastic model of such a wing, by coupling a linear membrane model to a well-validated steady laminar Navier–Stokes solver. The membrane deformation causes a significant pressure redistribution which increases lift and longitudinal static stability, though a drag penalty also develops. The efficiency of a rigid wing increases with Reynolds number, but decreases for a membrane wing, as the deformation generally provides a nonoptimal airfoil shape. Membrane deformation leads to larger separation bubbles, and acts as a barrier to the tip vortex formation. At high angles of attack, the aerodynamic twist causes a direct interaction be...
Estimated Age Effects in Baseball

Age effects in baseball are estimated in this paper using a nonlinear fixed-effects regression. The sample consists of all players who have played 10 or more "full-time" years in the major leagues between 1921 and 2004. Quadratic improvement is assumed up to a peak-performance age, which is estimated, and then quadratic decline after that, where the two quadratics need not be the same. Each player has his own constant term. The results show that aging effects are larger for pitchers than for batters and larger for baseball than for track and field, running, and swimming events and for chess. There is some evidence that decline rates in baseball have decreased slightly in the more recent period, but they are still generally larger than those for the other events. There are 18 batters out of the sample of 441 whose performances in the second half of their careers noticeably exceed what the model predicts they should have been. All but 3 of these players played from 1990 on. The estimates from the fixed-effects regressions can also be used to rank players. This ranking differs from the ranking using lifetime averages because it adjusts for the different ages at which players played. It is in effect an age-adjusted ranking.
Robust fault detection and monitoring of hybrid process systems with uncertain mode transitions

A methodology for fault detection and monitoring of a class of hybrid process systems modeled by switched nonlinear systems with control actuator faults, uncertain continuous dynamics, and uncertain mode transitions is presented. A robust hybrid monitoring scheme that distinguishes reliably between faults, mode transitions, and uncertainty is developed using tools from unknown input observer theory and results from Lyapunov stability theory. The monitoring scheme consists of (1) a family of dedicated mode observers that locate the active operating mode at any given time and detect mode switches, (2) a family of robust Lyapunov-based fault detection schemes that detect the faults within the continuous modes, and (3) a supervisor that synchronizes the switching between different controllers and different fault detectors as the process transitions from one mode to another. A key idea of the developed framework is to design the mode observers in a way that facilitates the identification of the active mode without information from the controllers and renders the residuals insensitive to the faults and uncertainties in the constituent subsystems. The implementation of the developed monitoring scheme is demonstrated using a simulated model of a chemical reactor that switches between multiple operating modes. © 2010 American Institute of Chemical Engineers AIChE J, 2011
On the average case performance of some greedy approximation algorithms for the uncapacitated facility location problem

In combinatorial optimization, a popular approach toNP-hard problems is the design of approximation algorithms. These algorithms typically run in polynomial time and are guaranteed to produce a solution which is within a known multiplicative factor of optimal. Unfortunately, the known factor is often known to be large in pathological instances. Conventional wisdom holds that, in practice, approximation algorithms will produce solutions closer to optimal than their proven guarantees. In this paper, we use the rigorous-analysis-of-heuristics framework to investigate this conventional wisdom.We analyze the performance of 3 related approximation algorithms for the uncapacitated facility location problem (from [Jain, Mahdian, Markakis, Saberi, Vazirani, 2003] and [Mahdian, Ye, Zhang, 2002]) when each is applied to an instances created by placing n points uniformly at random in the unit square. We find that, with high probability, these 3 algorithms do not find asymptotically optimal solutions, and, also with high probability, a simple plane partitioning heuristic does find an asymptotically optimal solution.
Efimov states with strong three-body losses

We determine analytically how Efimov trimer states are modified by three-body losses within the model of Braaten and Hammer. We find a regime where the energies approach the positive real axis and the decay rates vanish.
A new coumarin synthesis based on the aromatic metalation reaction

Abstract A convenient synthetic approach to coumarins and polycyclic coumarins based on the aromatic metalation reaction is described. Several polycyclic coumarins exhibit strong anticarcinogenic activity.