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Articles 1 - 30 of 44
Full-Text Articles in Physical Sciences and Mathematics
Black Holes With Magnetic Charge And Quantized Mass, A. Yu. Ignatiev, G. C. Joshi, Kameshwar C. Wali
Black Holes With Magnetic Charge And Quantized Mass, A. Yu. Ignatiev, G. C. Joshi, Kameshwar C. Wali
Physics - All Scholarship
We examine the issue of magnetic charge quantization in the presence of black holes. It is pointed out that quantization of magnetic charge can lead to the mass quantization for magnetically charged black holes. We also discuss some implications for the experimental searches of magnetically charged black holes.
Monte Carlo Renormalization Of 2d Simplicial Quantum Gravity Coupled To Gaussian Matter, Simon Catterall, Eric B. Gregory, G. Thorleifsson
Monte Carlo Renormalization Of 2d Simplicial Quantum Gravity Coupled To Gaussian Matter, Simon Catterall, Eric B. Gregory, G. Thorleifsson
Physics - All Scholarship
We extend a recently proposed real-space renormalization group scheme for dynamical triangulations to situations where the lattice is coupled to continuous scalar fields. Using Monte Carlo simulations in combination with a linear, stochastic blocking scheme for the scalar fields we are able to determine the leading eigenvalues of the stability matrix with good accuracy both for c = 1 and c = 10 theories.
New Analytical Results On Anisotropic Membranes, Mark Bowick, Alex Travesset
New Analytical Results On Anisotropic Membranes, Mark Bowick, Alex Travesset
Physics - All Scholarship
We report on recent progress in understanding the tubular phase of self-avoiding anisotropic membranes. After an introduction to the problem, we sketch the renormalization group arguments and symmetry considerations that lead us to the most plausible fixed point structure of the model. We then employ an epsilon-expansion about the upper critical dimension to extrapolate to the physical interesting 3-dimensional case. The results are $\nu=0.62$ for the Flory exponent and $\zeta=0.80$ for the roughness exponent. Finally we comment on the importance that numerical tests may have to test these predictions.
Dynamics Of The Conformal Mode And Simplicial Gravity, Simon Catterall, Emil Mottola, T. Bhattacharya
Dynamics Of The Conformal Mode And Simplicial Gravity, Simon Catterall, Emil Mottola, T. Bhattacharya
Physics - All Scholarship
We review the derivation of the Liouville action in 2DQG via the trace anomaly and emphasize how a similar approach can be used to derive an effective action describing the long wavelength dynamics of the conformal factor in 4D. In 2D we describe how to make an explicit connection between dynamical triangulations and this continuum theory, and present results which confirm the equivalance of the two approaches. By reconstructing a lattice conformal mode from DT simulations it should be possible to test this equivalence in 4D also.
Anisotropic Membranes, Simon Catterall, Mark Bowick, Simeon Warner, Gudmar Thorleifsson, Marco Falcioni
Anisotropic Membranes, Simon Catterall, Mark Bowick, Simeon Warner, Gudmar Thorleifsson, Marco Falcioni
Physics - All Scholarship
We describe the statistical behavior of anisotropic crystalline membranes. In particular we give the phase diagram and critical exponents for phantom membranes and discuss the generalization to self-avoiding membranes.
Putative Light Scalar Nonet, Joseph Schechter, Deirdre Black, Amir H. Fariborz, Francesco Sannino
Putative Light Scalar Nonet, Joseph Schechter, Deirdre Black, Amir H. Fariborz, Francesco Sannino
Physics - All Scholarship
We investigate the "family" relationship of a possible scalar nonet composed of the a_0(980), the f_0(980) and the \sigma and \kappa type states found in recent treatments of \pi\pi and \pi K scattering. We work in the effective Lagrangian framework, starting from terms which yield "ideal mixing" according to Okubo's original formulation. It is noted that there is another solution corresponding to dual ideal mixing which agrees with Jaffe's picture of scalars as qq\bar q \bar q states rather than as q\bar q states. At the Lagrangian level there is no difference in the formulation of the two cases (other …
The Tubular Phase Of Self-Avoiding Anisotropic Crystalline Membranes, Mark Bowick, Alex Travesset
The Tubular Phase Of Self-Avoiding Anisotropic Crystalline Membranes, Mark Bowick, Alex Travesset
Physics - All Scholarship
We analyze the tubular phase of self-avoiding anisotropic crystalline membranes. A careful analysis using renormalization group arguments together with symmetry requirements motivates the simplest form of the large-distance free energy describing fluctuations of tubular configurations. The non-self-avoiding limit of the model is shown to be exactly solvable. For the full self-avoiding model we compute the critical exponents using an epsilon-expansion about the upper critical embedding dimension for general internal dimension D and embedding dimension d. We then exhibit various methods for reliably extrapolating to the physical point (D=2,d=3). Our most accurate estimates are nu=0.62 for the Flory exponent and zeta=0.80 …
Disorder-Induced Topological Defects In A D=2 Elastic Medium At Zero Temperature, Alan Middleton
Disorder-Induced Topological Defects In A D=2 Elastic Medium At Zero Temperature, Alan Middleton
Physics - All Scholarship
The density and correlations of topological defects are investigated numerically in a model of a d=2 elastic medium subject to a periodic quenched random potential. The computed density of defects decreases approximately exponentially with the defect core energy. Comparing the defect-free ground state with the ground state with defects, it is found that the difference is described by string-like excitations, bounded by defect pairs, which have a fractal dimension of 1.250(3). At zero temperature, the disorder-induced defects screen the interaction of introduced vortex pairs.
H2 Formation On Interstellar Grains In Different Physical Regimes, Gianfranco Vidali, Ofer Biham, Itay Furman, N. Katz, Valerio Pirronello
H2 Formation On Interstellar Grains In Different Physical Regimes, Gianfranco Vidali, Ofer Biham, Itay Furman, N. Katz, Valerio Pirronello
Physics - All Scholarship
An analysis of the kinetics of H2 formation on interstellar dust grains is presented using rate equations. It is shown that semi-empirical expressions that appeared in the literature represent two different physical regimes. In particular, it is shown that the expression given by Hollenbach, Werner and Salpeter [ApJ, 163, 165 (1971)] applies when high flux, or high mobility, of H atoms on the surface of a grain, makes it very unlikely that H atoms evaporate before they meet each other and recombine. The expression of Pirronello et al.\ [ApJ, 483, L131 (1997)] -- deduced on the basis of accurate measurements …
Pion-Pion Scattering In Two Dimensions, Joseph Schechter, D. Delphenich, S. Vaidya
Pion-Pion Scattering In Two Dimensions, Joseph Schechter, D. Delphenich, S. Vaidya
Physics - All Scholarship
Massive two-flavor QED_2 is known to have many similarities to the two-flavor QCD_4. Here we compare the \pi-\pi scattering amplitudes (actually an analog process in QED_2) of the two theories. The QED_2 amplitude is computed from the bosonized version of the model while the QCD_4 amplitude is computed from an effective low energy chiral Lagrangian. A number of interesting features are noted. For example, the contribution of the two-dimensional Wess-Zumino-Witten (WZW) term in QED_2 is structurally identical to the vector meson exchange contribution in QCD_4. Also it is shown that the QED_2 amplitude computed at tree level is a reasonable …
Evidence For A Scalar Kappa(900) Resonance In Pi-K Scattering, Joseph Schechter, Deirdre Black, Amir H. Fariborz, Francesco Sannino
Evidence For A Scalar Kappa(900) Resonance In Pi-K Scattering, Joseph Schechter, Deirdre Black, Amir H. Fariborz, Francesco Sannino
Physics - All Scholarship
Motivated by the 1/N_c\ expansion, we study a simple model in which the pi-K scattering amplitude is the sum of a current-algebra contact term and resonance pole exchanges. This phenomenological model is crossing symmetric and, when a putative light strange scalar meson, kappa, is included, satisfies the unitarity bounds to well above 1 GeV. The model also features chiral dynamics, vector meson dominance and appropriate interference between the established scalar K*(1430) resonance and its predicted background. We briefly discuss the physical significance of the results and directions for further work.
Quadratic Electro-Optic Effects In Bacteriorhodopsin: Measurement Of Γ(-Ω;0,0,Ω) In Dried Gelatin Thin Films, Mikio Yamazaki, Jerry Goodisman, Robert R. Birge
Quadratic Electro-Optic Effects In Bacteriorhodopsin: Measurement Of Γ(-Ω;0,0,Ω) In Dried Gelatin Thin Films, Mikio Yamazaki, Jerry Goodisman, Robert R. Birge
Chemistry - All Scholarship
Quadratic electro-optic effects (dc or low frequency Kerr effect) of bacteriorhodopsin dispersed in dried gelatin thin films are examined in the near resonance region at three wavelengths: 633, 647, and 676 nm. The films show relatively large quadratic electro-optic effects compared to other molecular dispersed systems. The purple membrane is fixed within the polymerized gelatin matrix, and we show that the electronic contribution to γ dominates over possible orientational contributions. At 676 nm. the quadratic electro-optic coefficient s1133( - ω;0,0,ω) is 6.7 × 10-20 m2/V2 and the third order nonlinear susceptibility X1133(3) …
The Nature Of The Continuum Limit In The 2d Rp^2 Gauge Model, Simon Catterall, M. Hasenbusch, R. R. Horgan, R. Renken
The Nature Of The Continuum Limit In The 2d Rp^2 Gauge Model, Simon Catterall, M. Hasenbusch, R. R. Horgan, R. Renken
Physics - All Scholarship
The RP(2) gauge model is studied in 2D. We use Monte-Carlo renormalization techniques for blocking the mean spin-spin interaction, , and the mean gauge field plaquette. The presence of the O(3) renormalized trajectory is verified and is consistent with the known three-loop beta-function. The first-order `vorticity' transition observed by Solomon et al. is confirmed, and the location of the terminating critical point is established. New scaling flows in (,) are observed associated with a large exponent kappa in the range 4~5. The scaling flows give rise to a strong cross-over effect between regions of high and low vorticity …
Definitional Interpreters For Higher-Order Programming Languages, John C. Reynolds
Definitional Interpreters For Higher-Order Programming Languages, John C. Reynolds
College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects
Abstract. Higher-order programming languages (i.e., languages in which procedures or labels can occur as values) are usually defined by interpreters that are themselves written in a programming language based on the lambda calculus (i.e., an applicative language such as pure LISP). Examples include McCarthy’s definition of LISP, Landin’s SECD machine, the Vienna definition of PL/I, Reynolds ’ definitions of GEDANKEN, and recent unpublished work by L. Morris and C. Wadsworth. Such definitions can be classified according to whether the interpreter contains higher-order functions, and whether the order of application (i.e., call by value versus call by name) in the defined …
Dynamic Management Of Heterogeneous Resources, Jerrell Watts, Marc Rieffel, Stephen Taylor
Dynamic Management Of Heterogeneous Resources, Jerrell Watts, Marc Rieffel, Stephen Taylor
College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects
This paper presents techniques for dynamic load balancing in heterogeneous computing environments. That is, the techniques are designed for sets of machines with varying processing capabilities and memory capacities. These methods can also be applied to homogenous systems in which the effective compute speed or memory availability is reduced by the presence of other programs running outside the target computation. To handle heterogeneous systems, a precise distinction is made between an abstract quantity of work, which might be measured as the number of iterations of a loop or the count of some data structure, and the utilization of resources, measured …
Skew-Insensitive Parallel Algorithms For Relational Join, Khaled Alsabti, Sanjay Ranka
Skew-Insensitive Parallel Algorithms For Relational Join, Khaled Alsabti, Sanjay Ranka
College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects
Join is the most important and expensive operation in relational databases. The parallel join operation is very sensitive to the presence of the data skew. In this paper, we present two new parallel join algorithms for coarse grained machines which work optimally in presence of arbitrary amount of data skew. The first algorithm is sort-based and the second is hash-based. Both of these algorithms employ a preprocessing phase (prior to the redistribution phase) to equally partition the work among the processors. The proposed algorithms have been designed for memory resident-data. However, they can be extended to disk resident-data. These algorithms …
Visual Interactive Modeling In A Java-Based Hierarchical Modeling And Simulation System, Robert G. Sargent, Thorsten Daum
Visual Interactive Modeling In A Java-Based Hierarchical Modeling And Simulation System, Robert G. Sargent, Thorsten Daum
College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects
The desired set of properties of a modern simulation system is presented. The portion of the Hierarchical Modeling And Simulation System-Java (HiMASS-j) used for specifying Hierarchical Control Flow Graph (HCFG) Models is described. The specification of HCFG Models in HiMASS-j is by visual interactive modeling through the use of graphical user interfaces and dialog boxes. HCFG Models are specified using two complementary hierarchical specification structures: one to specify the components that comprise a model and how these components are interconnected, and the other to specify the behaviors of individual atomic components. A simulation of a traffic intersection using HiMASS-j is …
Arginine To Glutamine Substitutions In The Fourth Module Of Xenopus Interphotoreceptor Retinoid-Binding Protein, Mark S. Braiman, Claxton A. Baer, Ellen E. Van Niel, Jeffrey W. Cronk, Michael T. Kinter, Nicholas E. Sherman, Federico Gonzalez-Fernandez
Arginine To Glutamine Substitutions In The Fourth Module Of Xenopus Interphotoreceptor Retinoid-Binding Protein, Mark S. Braiman, Claxton A. Baer, Ellen E. Van Niel, Jeffrey W. Cronk, Michael T. Kinter, Nicholas E. Sherman, Federico Gonzalez-Fernandez
Chemistry - All Scholarship
Interphotoreceptor retinoid-binding protein (IRBP) is unusual for a lipid-binding protein in that its gene is expressed uniquely by cells of photoreceptor origin and consists of four homologous repeats, each coding for a module of~300 amino acid residues. All-trans retinol binding domains, which appear to be present in each module, are composed of conserved hydrophobic regions [Baer et al, Exp Eye Res 1998; 66:249-262]. Here we investigate the role of highly conserved arginines contained in these regions.
Verification And Validation Of Simulation Models, Robert G. Sargent
Verification And Validation Of Simulation Models, Robert G. Sargent
Electrical Engineering and Computer Science - All Scholarship
This paper discusses verification and validation of simulation models. The different approaches to deciding model validity are presented; how model verification and validation relate to the model development process are discussed; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are described; ways to document results are given; and a recommended procedure is presented.
A Global Communication Optimization Technique Based On Data-Flow Analysis And Linear Algebra, Mahmut Kandemir, P. Banerjee, Alok Choudhary, J. Ramanujam
A Global Communication Optimization Technique Based On Data-Flow Analysis And Linear Algebra, Mahmut Kandemir, P. Banerjee, Alok Choudhary, J. Ramanujam
Electrical Engineering and Computer Science - All Scholarship
Reducing communication overhead is extremely important in distributed-memory message-passing architectures. In this paper, we present a technique to improve communication that considers data access patterns of the entire program. Our approach is based on a combination of traditional data-flow analysis and a linear algebra framework, and works on structured programs with conditional statements and nested loops but without arbitrary goto statements. The distinctive features of the solution are the accuracy in keeping communication set information, support for general alignments and distributions including block-cyclic distributions and the ability to simulate some of the previous approaches with suitable modifications. We also show …
Clouds: A Decision Tree Classifier For Large Datasets, Khaled Alsabti, Sanjay Ranka, Vineet Singh
Clouds: A Decision Tree Classifier For Large Datasets, Khaled Alsabti, Sanjay Ranka, Vineet Singh
Electrical Engineering and Computer Science - All Scholarship
Classification for very large datasets has many practical applications in data mining. Techniques such as discretization and dataset sampling can be used to scale up decision tree classifiers to large datasets. Unfortunately, both of these techniques can cause a significant loss in accuracy. We present a novel decision tree classifier called CLOUDS, which samples the splitting points for numeric attributes followed by an estimation step to narrow the search space of the best split. CLOUDS reduces computation and I/O complexity substantially compared to state of the art classifiers, while maintaining the quality of the generated trees in terms of accuracy …
Design, Implementation, And Evaluation Of Parallell Pipelined Stap On Parallel Computers, Alok Choudhary, Wei-Keng Liao, Donald Weiner, Pramod Varshney, Richard Linderman, Mark Linderman
Design, Implementation, And Evaluation Of Parallell Pipelined Stap On Parallel Computers, Alok Choudhary, Wei-Keng Liao, Donald Weiner, Pramod Varshney, Richard Linderman, Mark Linderman
Electrical Engineering and Computer Science - All Scholarship
Performance results are presented for the design and implementation of parallel pipelined space-time adaptive processing (STAP) algorithms on parallel computers. In particular, the issues involved in parallelization, our approach to parallelization, and performance results on an Intel Paragon are described. The process of developing software for such an application on parallel computers when latency and throughput are both considered together is discussed and tradeoffs considered with respect to inter and intratask communication and data redistribution are presented. The results show that not only scalable performance was achieved for individual component tasks of STAP but linear speedups were obtained for the …
Adaptive Linkage Crossover, Ayed A. Salman, Kishan Mehrotra, Chilukuri K. Mohan
Adaptive Linkage Crossover, Ayed A. Salman, Kishan Mehrotra, Chilukuri K. Mohan
Electrical Engineering and Computer Science - All Scholarship
Problem-specific knowledge is often implemented in search algorithms using heuristics to determine which search paths are to be explored at any given instant. As in other search methods, utilizing this knowledge will more quickly lead a genetic algorithm (GA) towards better results. In many problems, crucial knowledge is not found in individual components, but in the interrelations between those components. For such problems, we develop an interrelation (linkage) based crossover operator that has the advantage of liberating GAs from the constraints imposed by the fixed representations generally chosen for problems. The strength of linkages between components of a chromosomal structure …
A Multithreaded Message-Passing System For High Performance Distributed Computing Applications, Sung-Yong Park, Joohan Lee, Salim Hariri
A Multithreaded Message-Passing System For High Performance Distributed Computing Applications, Sung-Yong Park, Joohan Lee, Salim Hariri
Electrical Engineering and Computer Science - All Scholarship
High Performance Distributed Computing (HPDC) applications require low-latency and high-throughput communication services and HPDC applications have different Quality of Service (QOS) requirements (e.g., bandwidth requirement, flow/error control algorithms, etc.). The communication services provided by traditional message-passing systems are fixed and thus can not be changed to meet the requirements of different HPDC applications. NYNET (ATM wide area network testbed in New York state) Communication System (NCS) is a multithreaded message-passing system developed at Syracuse University that provides high-performance and flexible communication services. In this paper, we overview the general architecture of NCS and present how NCS communication services are implemented. …
Steady State Memetic Algorithm For Partial Shape Matching, Ender Ozcan, Chilukuri K. Mohan
Steady State Memetic Algorithm For Partial Shape Matching, Ender Ozcan, Chilukuri K. Mohan
Electrical Engineering and Computer Science - All Scholarship
Shape matching techniques are important in machine intelligence, especially in applications such as robotics. Currently, there are three major approaches to shape recognition: statistical, syntactic and neural approaches. This paper presents a fourth approach: evolutionary algorithms. A steady state memetic algorithm is shown to be successful in matching shapes even when they are partially obscured, and even in the presence of noise in the input image.
Integrating Security Into The Curriculum, Cynthia E. Irvine, Shiu-Kai Chin, Deborah Frincke
Integrating Security Into The Curriculum, Cynthia E. Irvine, Shiu-Kai Chin, Deborah Frincke
Electrical Engineering and Computer Science - All Scholarship
The number of skilled practitioners of computer security who are able to address the complexities of modern technology and are familiar with successful approaches to system security is very small. People want security but are faced with two difficulties. First, they do not know how to achieve it in the context of their enterprises. They may not even know of a way to translate organizational procedures into policies, much less implement a set of mechanisms to enforce those policies. Second, they have no way of knowing whether their chosen mechanisms are effective. The recent US Presidential Commission on Critical Infrastructure …
Partial Shape Matching Using Genetic Algorithms, Ender Ozcan, Chilukuri K. Mohan
Partial Shape Matching Using Genetic Algorithms, Ender Ozcan, Chilukuri K. Mohan
Electrical Engineering and Computer Science - All Scholarship
Shape recognition is a challenging task when images contain overlapping, noisy, occluded, partial shapes. This paper addresses the task of matching input shapes with model shapes described in terms of features such as line segments and angles. The quality of matching is gauged using a measure derived from attributed shape grammars. We apply genetic algorithms to the partial shape-matching task. Preliminary results, using model shapes with 6 to 70 features each, are extremely encouraging.
The Design And Evaluation Of A Virtual Distributed Computing Environment, Haluk Topcuoglu, Salim Hariri, Dongmin Kim, Yoonhee Kim, Xue Bing
The Design And Evaluation Of A Virtual Distributed Computing Environment, Haluk Topcuoglu, Salim Hariri, Dongmin Kim, Yoonhee Kim, Xue Bing
Electrical Engineering and Computer Science - All Scholarship
In this paper we present the Virtual Distributed Computing Environment (VDCE), a metacomputing environment currently being developed at Syracuse University. VDCE provides an efficient web-based approach for developing, evaluating and visualizing large-scale distributed applications that are based on predefined task libraries on diverse platforms. The VDCE task libraries relieve end-users of tedious task implementations and also support reusability. The VDCE software architecture is described in terms of three modules: a) the Application Editor, a user-friendly application development environment that generates the Application Flow Graph (AFG) of an application; b) the Application Scheduler, which provides an efficient task-to-resource mapping of AFG; …
An Efficient Parallel Algorithm For High Dimensional Similarity Join, Khaled Alsabti, Sanjay Ranka, Vineet Singh
An Efficient Parallel Algorithm For High Dimensional Similarity Join, Khaled Alsabti, Sanjay Ranka, Vineet Singh
Electrical Engineering and Computer Science - All Scholarship
Multidimensional similarity join finds pairs of multi-dimensional points that are within some small distance of each other: The 6-k-d-B tree has been proposed as a data structure that scales better as the number of dimensions in-creases compared to previous data structures. We present a cost model of the E-k-d-B tree and use it to optimize the leaf size. We present novel parallel algorithms for the similarity join using the E-k-d-B tree. A load-balancing strategy based on equi-depth histograms is shown to work well for uniform or low-skew situations, whereas another based on weighted equi-depth histograms works far better for high-skew …
Secure Delegation For Distributed Object Environments, Nataraj Nagaratnam, Doug Lea
Secure Delegation For Distributed Object Environments, Nataraj Nagaratnam, Doug Lea
Electrical Engineering and Computer Science - All Scholarship
SDM is a Secure Delegation Model for Java-based distributed object environments. SDM extends current Java security features to support secure remote method invocations that may involve chains of delegated calls across distributed objects. The framework supports a control API for application developers to specify mechanisms and security policies surrounding simple or cascaded delegation. Delegation may also be disabled and optionally revoked. These policies may be controlled explicitly in application code, or implicitly via administrative tools.