ppxscal/embedding_network huggingface dataset:
Two Way Deterministic Pushdown Automaton Languages and Some Open Problems in the Theory of Computation
Authors: Zvi Galil
Venue:  (1974)

We consider some of the important unsolved problems in the theory of computation concerning the relationship between deterministic and nondeterministic computations, and between tape and time bounded computations. For each such problem we find an equivalent problem concerning two way deterministic pushdown automaton languages. This is the first time many of the open problems have been reduced to questions about one class of automata. Keywords and phrases: Two way deterministic pushdown automata, open problems, determinism versus nondeterminism, space bounded computations, time bounded computations, Turing machines, multihead pushdown automata, two way counter machines, auxiliary pushdown machines. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Modeling and Verifying Strong Cache Consistency for Mobile Data Access
Authors: Jun Wei, Shing-Chi Cheung, Huan Zhou, Xu Wang, Jing Li, Yu-Lin Feng
Venue: Proceedings of the 12th International Symposium on Software Reliability Engineering (2001)

Recent advances in wireless and mobile networks have led to the exponential growth of mobile applications.Unlike conventional computing, mobile computing has stringentconstraints in network resources, such as bandwidth and connectivity.As such, data in mobile applications are often cached at clients to increase performance, dataavailability and reliability.Formal verification of cache coherence in data access is essential in ascertaining the validity of a cache coherence protocol.Although a number of studies have been made in this subject, few researchers focused on mobile data access.In this paper, we presentan automatic approach towards formal validation of a cache validation protocol supporting mobile data access. This approach combines the flexibility of visual modeling techniques with the rigor of formal validation.As it is difficult to construct the formal model of protocol, we have developed a set of formalization and translation rules toautomate the process of construction. The reliability of the protocol has been verified using model checking.
Focus Points and Convergent Process Operators
Authors: Jan F Groote, Jan G. Springintveld
Venue:  (1995)

We present a strategy for finding algebraic correctness proofs for communication systems. It is described in the setting of $\mu$CRL (Groote and Ponse 93) which is, roughly, ACP (Baeten and Weijland 90, Bergstra and Klop 84) extended with a formal treatment of the interaction between data and processes. The strategy has already been applied successfully in non-trivial case studies (e.g., Bezem and Groote 94, and Fredlund, Groote, and Korver 95), but was not explicitly identified as such. Moreover, the protocols that were verified in these papers were rather complex, so that the general picture was obscured by the amount of details. In this paper, the proof strategy is materialised in the form of definitions and theorems. These results reduce a large part of protocol verification to a number of trivial facts concerning data parameters occurring in implementation and specification. This greatly simplifies protocol verifications and makes our approach amenable to mechanical assistance; experiments in this direction seem promising. The strategy is illustrated by several small examples and one larger example, the Concurrent Alternating Bit Protocol (CABP). Although simple, this protocol contains a large amount of internal parallelism, so that all relevant issues make their appearance.
The Computer Incidence Response Puzzle: A Guide to Forming an Incident Response Team
Authors: Lucas, Brian Moeller
Venue:  (2003)

When an intruder, worm, virus, or automated attack succeeds in targeting a computer system, having specific controls and a response plan in place can greatly lessen losses. Accordingly, businesses are realizing that it is unwise to invest resources in preventing computer-related security incidents without equal consideration of how to detect and respond to such attacks and breaches.The Effective Incident Response Team is the first complete guide to forming and managing a Computer Incident Response Team (CIRT). In this book, system and network administrators and managers will find comprehensive information on establishing a CIRT's focus and scope, complete with organizational and workflow strategies for maximizing available technical resources. The text is also a valuable resource for working teams, thanks to its many examples of day-to-day team operations, communications, forms, and legal references.IT administrators and managers must be prepared for attacks on any platform, exploiting any vulnerability, at any time. The Effective Incident Response Team will guide readers through the critical decisions involved in forming a CIRT and serve as a valuable resource as the team evolves to meet the demands of ever-changing vulnerabilities.Inside, readers will find information on: Formulating reactive or preventative operational strategy Forming, training, and marketing the CIRT Selecting penetration-testing, intrusion-detection, network-monitoring, and forensics tools Recognizing and responding to computer incidents and attacks, including unauthorized access, denial-of-service attacks, port scans, and viruses Tracking, storing, and counting incident reports and assessing the cost of an incident Working with law enforcement and the legal community Benefiting from shared resources Scrutinizing closed incidents to further prevention Offering services such as user-awareness training, vulnerability and risk assessments, penetration testing, and architectural reviews Communicating the CIRT's return on investment through management reporting 0201761750B10062003
A Framework for Multi-Notation Requirements Specification and Analysis
Authors: Nancy A. Day, Jeffrey J. Joyce
Venue: Proceedings of the 4th International Conference on Requirements Engineering (ICRE'00) (2000)

Many organizations desire the convenience of using multiple notations within a requirements specification. Rather than using separate tools for each notation, we advocate combining the parts semantically for tool-based analysis. We describe a framework for integrating notations from four distinct categories, namely, ¿models¿, ¿events¿, ¿actions¿, and ¿expressions¿. The categories allow us to view the notations independently, but in a manner whereby they can be combined to create a specification. The categories are implemented as types in higher-order logic. Type checking ensures conformance to the rules for combining notations. Our choice of higher-order logic as a base formalism allows the framework to support notations with uninterpreted constants. With our framework, it is possible to use new combinations of notations without changing existing notations or rebuilding formal analysis tools such as model checkers.
Dynamical Behavior of Magnetic Fields in a Stratified, Convecting Fluid Layer
Authors: Steven R. Lantz
Venue:  (1991)

Time-dependent magnetohydrodynamic (MHD) convection is studied by numerical modeling on several levels. An intuitive model, the mixing length theory of convection (MLT), is reviewed; from this, a scaling law for convective structures is derived and compared with observations of the solar convection zone. MLT lays the foundation for the magentoanelastic equations--a model for MHD convection at low Mach and Alfaven Mach numbers--which is rederived with particular attention to its relation to the familiar Boussinesq equations. A variant of the anelastic approximation is offered which obviates the need for a first-order pressure equation. The magneto-anelastic model is used as the basis for SUMO, a computer model that generates numerical solutions on a two-dimensional Cartesian mesh by a finite-difference, predictor-corrector algorithm. Thermodynamic properties of the fluid are held fixed and constant at the rigid, stress-free top and bottom boundaries of the computational box, while lateral boundaries are treated as periodic. A numerical study of the equations is made for a zero-order polytrope, at a Rayleigh number 5.44 times the critical value, Prandtl number 1.8, and aspect zero unity. The dynamical behavior is highly influenced by a horizontal magnetic field which is imposed at the bottom boundary (the top of the domain is attached to a nonconducting region). As the magnetic parameter is increased, the initially tilted character of convection rolls changes. A single-roll, highly sheared, timedependent state is replaced by a steady "traveling-wave" tilted state; then an oscillatory or "sloshing" state; then a steady two-roll state with no tilting; and finally, a stationary state. The concentrated nature of magnetic fields at the top of these flows is explained by a simple advection-diffusion balance. The complex dynamical behavior is shown to be well-represented by a nine-mode truncation of the Fourier expansion of the Boussinesq equations in a uniform, horizontal magnetic field. The key mode is a "tilting" one, which breaks the up-down mirror symmetry. Qualitative and quantitative comparisons are made between the simulations and the nine-mode model, which demonstrate that the latter captures all the essential physics of the former.
The approximate inverse in action II: convergence and stability
Authors: Andreas Rieder, Thomas Schuster
Venue: Mathematics of Computation (2003)

The approximate inverse is a scheme for constructing stable inversion formulas for operator equations. Originally, it is defined on L2-spaces. In the present article we extend the concept of approximate inverse to more general settings which allow us to investigate the discrete version of the approximate inverse which actually underlies numerical computations. Indeed, we show convergence if the discretization parameter tends to zero. Further, we prove stability, that is, we show the regularization property. Finally we apply the results to the filtered backprojection algorithm in 2D-tomography to obtain convergence rates.
Static and Adaptive Data Replication Algorithms for Fast Information Access in Large Distributed Systems
Authors: Thanasis Loukopoulos, Ishfaq Ahmad
Venue: Proceedings of the The 20th International Conference on Distributed Computing Systems ( ICDCS 2000) (2000)

Creating replicas of frequently accessed objects across a read-intensive network can result in large bandwidth savings, which, in turn, can lead to reduction in user response time. On the contrary, data replication in the presence of writes incurs extra cost due to multiple updates. The set of sites at which an object is replicated constitutes its replication scheme. Finding an optimal replication scheme that minimizes the amount of network traffic, given read and write frequencies for various objects, is NP-complete in general.We propose two heuristics to deal with this problem for static read and write patterns. The first is a simple and fast greedy heuristic that yields good solutions when the system is predominantly read-oriented. The second is a genetic algorithm that through an efficient exploration of the solution space provides better solutions for cases where the greedy heuristic does not perform well. We also propose an extended genetic algorithm that rapidly adapts to the dynamically changing characteristics such as the frequency of reads and writes for particular objects.
Visualization of virtual architecture
Authors: B. Senyapili
Venue: Proceedings of the IEEE Conference on Information Visualisation (1997)

The study constitutes a framework, a justification and a proposal for the opportunity to improve the use and efficiency of visualization of architecture in the virtual environment. It seeks a new platform to define architectural design communication. The design process depends upon creation of models and virtual environment offers the medium of exchange where the design model can be shared and criticized by people other than the designer; various analysis can be applied and the results of both can be used to change or improve the design. Possibilities offered by visualization do not fit into the paper based way of architectural thinking. In order to benefit from the potential of visualization it is required to redefine architecture, architectural design process and architectural terms with respect to the virtual environment. The study introduces a transitional solution between the paper based and the future ways of thinking in architecture by enabling the designers to customize the visualization software according to their purposes.
Assessment of a Human Computer Interface Prototyping Environment
Authors: L. A. Moore
Venue:  (1993)

A Human Computer Interface (HCI) prototyping environment with embedded evaluation capability has been successfully assessed which will be valuable in developing and refining HCI standards and evaluating program/project interface development, especially Space Station Freedom on board displays for payload operations. The HCI prototyping environment is designed to include four components: (1) a HCI format development tool, (2) a test and evaluation simulator development tool, (3) a dynamic, interactive interface between the HCI prototype and simulator, and (4) an embedded evaluation capability to evaluate the adequacy of an HCI based on a user''s performance. The objectives of this research were to evaluate components 1, 2, and 4. The system chosen for empirical evaluation of this HCI prototyping environment was an automobile. Components of the dynamic prototyping environment were assessed in a two phase effort. During Phase I, the requirements for the automobile interface and simulator were developed. During Phase II, evaluation criteria for the operation of the automobile prototype were developed.
Adaptive Bubble Router: A Design to Improve Performance in Torus Networks
Authors: V. Puente, R. Beivide, J. A. Gregorio, J. M. Prellezo, J. Duato, C. Izu
Venue: Proceedings of the 1999 International Conference on Parallel Processing (1999)

A router design for torus networks that significantly reduces message latency over traditional wormhole routers is presented in this paper. This new router implements virtual cut-through switching and fully-adaptive minimal routing. Packet deadlock is avoided by providing escape ways governed by Bubble flow control, a mechanism that guarantees enough free buffer space in the network to allow continuous packet movement.Both deterministic and adaptive Bubble routers have been designed in VLSI using VHDL synthesis tools. Adopting a fair quantitative comparison, we demonstrate that Bubble routers exhibit a reduction in base latency values over 40% with respect to the corresponding wormhole routers, without any penalty in network throughput. With much lower VLSI costs than adaptive wormhole routers, the adaptive Bubble router is even faster than deterministic wormhole routers based on virtual channels.
Windows Game Programming For Dummies, 2 edition
Authors: Andre LaMothe
Venue:  (2002)

:Get the scoop on DirectDraw, DirectInput physics modeling, and more!The one book you need to begin building your own gamesGame programming is a challenge - even if you're a veteran C/C++ programmer. This friendly guide by a legendary game developer delivers just what you need to get started on 2D games. Now revised to cover the latest DirectX and Windows releases, it shows you step by step how to tackle everything from graphics and sound to input and installation - even games marketing!All this on the bonus CD-ROMMicrosoft DirectX application programming interface SDK v. 8.1Paint Shop Pro evaluation versionExamples, games, and source code from the bookPlus bonus chaptersSystem Requirements: PC running Windows 9x/2000/Me/XP, Windows NT 4 or later; 64MB of RAM, 128MB recommended. See the About the CD Appendix for details and complete system requirements.
The uniform convergence of subsequences of the last intermediate row of the Padé table
Authors: Victor M. Adukov
Venue: Journal of Approximation Theory (2003)

In the work the uniform convergence of rows of the Padé approximants for a meromorphic function a(z) is studied. The complete description of the asymptotic behavior of denominators Qn(z) of the Padé approximants is obtainedt for the (λ -- 1)th row. Here λ is the number of the poles of a(z). The limits of all convergent subsequences of {Qn(z)} are explicitly computed. These limits form a family of polynomials which is parametrized by a monothetic subgroup F of the torus Tv. The group F is constructed via the arguments Θ1.....Θv of those poles of a(z) of the maximal modulus that have the maximal multiplicity.
Efficient Sequential and Parallel Algorithms for the Negative Cycle Problem
Authors: Dimitrios Kavvadias, Grammati E. Pantziou, Paul G. Spirakis, Christos D. Zaroliagis
Venue:  (1994)

We present here an algorithm for detecting (and outputting, if exists) a negative cycle in an $n$-vertex planar digraph $G$ with real edge weights. Its running time ranges from $O(n)$ up to $O(n^{1.5}\log n)$ as a certain topological measure of $G$ varies from $1$ up to $\Theta(n)$. Moreover, an efficient CREW PRAM implementation is given. Our algorithm applies also to digraphs whose genus $\gamma$ is $o(n)$.
A multicast ATM switch with slotted ring fabric
Authors: R. R. Henry
Venue: Proceedings of the 6th International Conference on Computer Communications and Networks (1997)

This paper proposes a scalable, optical fiber, slotted ring ATM switch architecture. The internal switching fabric and transport mechanism is developed, a model formulated, and deterministic performance analysis equations derived. The delay and blocking performance metrics of a 16/spl times/16 switch with 150 Mbps links are given. It is shown that zero blocking performance can be achieved, as can delays as low as several bit times.
Progressive failure studies of composite panels with and without cutouts
Authors: Jaunky Navin, Ambur Damodar R., Davila Carlos G., Hilburger Mark
Venue:  (2001)

Progressive failure analyses results are presented for composite panels with and without a cutout and subjected to in-plane shear loading and compression loading well into their postbuckling regime. Ply damage modes such as matrix cracking, fiber-matrix shear, and fiber failure are modeled by degrading the material properties. Results from finite element analyses are compared with experimental data. Good agreement between experimental data and numerical results are observed for most structural configurations when initial geometric imperfections are appropriately modeled.
Spectral Calculations of Viscoelastic Flows: Evaluation of the Giesekus Constitutive Equation in Model Flow Problems
Authors: Antony Beris, Marios Avgousti, Athanassios Souvaliotis
Venue:  (1992)

Spectral solutions of viscoelastic flow equations offer significant advantages emanating from their high, exponentially fast converging with mesh refinement, accuracy of the solutions. The analysis of the behavior of the Giesekus model is presented in a) the undulating channel steady-state flow and b) the evolution of Taylor-Couette flow instabilities. By comparison to the results corresponding to an inelastic shear thinning analog, it is shown that the presence of elasticity, while it introduces a minor change in the flow resistance for the flow within an undulating channel, significantly affects the stability of the Couette flow. In aedition, no purely elastic (inertialess) instability is obtained in the Couette flow, in contrast to the Oldroyd-B fluid calculations. Thus, the stabilizing effect of the negative second normal stress, present in the Giesekus model, is verified.
Associativeness versus Recursiveness
Authors: V. Cutello E. Molina, J. Montero
Venue: Proceedings of the 26th International Symposium on Multiple-Valued Logic (1996)

Fuzzy connectives use to be assumed associative. In this way, key operational difficulties are solved by means of a single binary operator. In this paper we point out that the main property in order to assure operativeness should be recursiveness, which is weaker than associativity. If calculus can be obtained by means of a recursive application of a sequence of binary connectives, we still can develop operative models. It is then clearly seen that a fuzzy rule should be always understood as a family of fuzzy connectives. Associativity will appear when a fuzzy rule can be characterized by a single binary connective. Associativity assumption is therefore excluding from our model key rules in practice.
Accurate and efficient pricing of vanilla stock options via the Crandall--Douglas scheme
Authors: Brian J. McCartin, Suzanne M. Labadie
Venue: Applied Mathematics and Computation (2003)

In this paper, we apply the Crandall-Douglas scheme [Quarterly of Applied Mathematics 13 (1955) 318-320, Journal of Mathematics and Physics 35 (1956) 145-151] for the heat equation to the computation of vanilla stock option prices. This method has the advantage of being second-order accurate in time and fourth-order accurate in "space" (i.e., asset price) and can even be made sixth-order accurate if we restrict the size of the time step. Although there is an exact solution for European options, we study their numerical approximation so as to determine suitable discretization parameters and permit reasonable placement of the far-field boundary. We then turn to American options where there are no analytical pricing formulae. Discretization of the associated free boundary problem, when expressed as a variational inequality, leads to a linear complementarity problem at each time step. These subproblems are solved in linear time by the Elliott-Ockendon algorithm [Weak and Variational Methods for Moving Boundary Problems, Pitman, 1982, pp. 115-117]. The net result is an option pricing methodology which is both very accurate and highly efficient. We present the application of our numerical scheme to calls paying continuous dividends as well as to puts, in both cases permitting early exercise of the option.
User''s Guide to Release 2, PL/CS
Authors: T. Bishop, Richard W. Conway
Venue:  (1977)

NO SUPPLIED
Graph-Theoretic Approaches to Fault-Tolerant Processor Arrays
Authors: L A Rosenberg
Venue:  (1985)

We describe a graph-theoretic formulation of the problem of designing fault-tolerant arrays of identical processing elements, and we present three design strategies that build on this formulation to solve a demanding version of the fault-tolerant array problem. Two of the strategies employ graph {\em separation} as their primary tool, while the third uses graph {\em vertex-coloring}. At least in our idealized framework, the layouts produced by these strategies require surprisingly little overhead (in area and extra ``hardware'''') to achieve their tolerance to faults.
Why Is It so Difficult to Introduce Requirements Engineering Research Results into Mainstream Requirements Engineering Practice?
Authors: Hermann Kaindl
Venue: Proceedings of the 4th International Conference on Requirements Engineering (ICRE'00) (2000)

While research results in requirements engineering (RE) were developed without much interaction with or impact on practice for quite a long time, Hsia et al. [1] made an honest evaluation of the requirements engineering practice. Since then, some improvements have been achieved, e.g., by some applications of usage scenarios. Still, mainstream practice is to use one's favorite word processor to write down mostly unstructured text in natural language, even though some good experience exists that used RE results in real projects (see, e.g., [2, 3]). In fact, mainstream practice only rudimentarily deals with requirements at all, and what is done might not even deserve to be called ¿engineering¿.
Polygon Scan Conversion Derivations
Authors: Kurt Fleischer
Venue:  (1995)

No Abstract.