Parallelization of a Hyper-Linking–Based Theorem Prover

We describe the parallelization of a first-order logic theorem prover that is based on the hyper-linking proof procedure (HLPP). Four parallel schemes – process level, clause level, literal level, and flow level – are developed for two types of sequential implementation of HLPP: list based and network based. The motivation for developing each parallel scheme is presented, and the architecture and implementation details of each scheme are described. Issues about parallel processing, such as serialization and synchronization, load balancing, and access conflicts, are examined. Speedups over sequential implementations are attained, and timing results for benchmark problems are provided.     

′97 Model收入增长61％

1988年3月2日,明导资讯有限公司的全资子公司Model Technology公司宣布其1997年总收入比1996年增长了61％,在VHDL和混合HDL仿真领域处于领先地位。 Model Technology公司VHDL与Verilog仿真产品的增长超过了工业增长率。1997年,Model Technolngy公司的ModelSim/VHDL产品的销售比1996年增长了46％,而其Verilog产品ModelSim/VLOG的销售则增长了228％。     

Parallelization of Algorithms and Codes of the Computational System “Potok-3”

The paper discusses creation of modern computational technologies and methods of parallel programming aimed at improving efficiency of solving fundamental scientific and applied problems. Primary attention is focused on theoretical issues and practical implementation of technological decomposition and parallelization of algorithms and codes of the computational system Potok-3, which is designed for the numerical modeling of aerodynamics and physical gas dynamics problems. General problems of portability of methods and algorithms, as well as program packages implementing them, designed for single-processor machines to multiprocessor computational systems are discussed.     

Generalization of Krasnoshchekov’s Model for the Case of a Decomposable Matrix of Social Interactions

In this work, Krasnoshchekov’s model, which describes the behavior of people in a community under social and informational influences, is generalized to include the case of a system with a sophisticated structure of social interaction. In particular, the situation when an isolated group of people is formed who are not familiar with the rest of the community, which corresponds to a decomposable matrix of social interactions, is studied. The conditions for the solution of the system of equations describing the behavior of such a community to exist and be unique are considered. The problem of finding the relation between Krasnoshchekov’s and De Groot’s models is solved. The way this matrix of social interactions and the social independence of individuals affect the structure of the solution of this system, which describes in particularl how beliefs spread among people, is studied.     

Using Reason’s Model of Organisational Accidents in Formalising Accident Reports

This paper proposes a method for analysing what are called organisational accidents. The first step of the method involves using Reason’s model of organisational failures. This provides heuristic guidance in identifying both the active and latent conditions that lead to major failures. The second step involves applying formal methods to support a detailed analysis of each latent and active condition. The method is demonstrated on a case study: the railway accident at Watford Junction in the United Kingdom. Analysis of the formal model helps to identify organisational factors that might have prevented the accident. It also helps to identify weaknesses in the report itself. In particular we argue that a signalling standard was misunderstood, the consequences of which could lead to another serious accident.     

Analysis of Nonlinear Spectral Eddy-Viscosity Models of Turbulence

Fluid turbulence is commonly modeled by the Navier-Stokes equations with a large Reynolds number. However, direct numerical simulations are not possible in practice, so that turbulence modeling is introduced. We study artificial spectral viscosity models that render the simulation of turbulence tractable. We show that the models are well posed and have solutions that converge, in certain parameter limits, to solutions of the Navier-Stokes equations. We also show, using the mathematical analyses, how effective choices for the parameters appearing in the models can be made. Finally, we consider temporal discretizations of the models and investigate their stability.     

Superconvergence of Jacobi–Gauss-Type Spectral Interpolation

In this paper, we extend the study of superconvergence properties of Chebyshev-Gauss-type spectral interpolation in Zhang (SIAM J Numer Anal 50(5):2966–2985, 2012) to general Jacobi–Gauss-type interpolation. We follow the same principle as in Zhang (SIAM J Numer Anal 50(5):2966–2985, 2012) to identify superconvergence points from interpolating analytic functions, but rigorous error analysis turns out much more involved even for the Legendre case. We address the implication of this study to functions with limited regularity, that is, at superconvergence points of interpolating analytic functions, the leading term of the interpolation error vanishes, but there is no gain in order of convergence, which is in distinctive contrast with analytic functions. We provide a general framework for exponential convergence and superconvergence analysis. We also obtain interpolation error bounds for Jacobi–Gauss-type interpolation, and explicitly characterize the dependence of the underlying parameters and constants, whenever possible. Moreover, we provide illustrative numerical examples to show tightness of the bounds.     

Spectral identification of ozone‐damaged pine needles

Needles were collected from ponderosa and Jeffrey pine trees at three sites in the Sierra Nevada, and were assembled into 504 samples and grouped according to five dominant live needle conditions – green, winter fleck, sucking insect damage, scale insect damage, and ozone damage – and a random mixture. Reflectance and transmittance measurements of abaxial and adaxial surfaces were obtained at ca 0.3 nm spectral resolution from 400–800 nm, and binned to simulate Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) data. There were no significant differences in optical properties between the two surfaces. Ozone‐damaged needles were collected from Jeffrey pine trees at one site, and exhibited significantly different (family‐wise α = 0.01) reflectance and transmittance signatures – and significantly different signature slopes – at both spectral resolutions, from green and winter fleck needles from the same site. Ozone‐damaged needles had significantly different (family‐wise α = 0.01) abaxial surface reflectance and reflectance slope signatures from all other groups of needles, at both spectral resolutions. In comparison with three chlorophyll reflectance indices, a new red fall index (RFI) provides high classification accuracies for ozone‐damaged and non‐ozone‐damaged pine needles (overall acc. = 94%; κ = 59%). Thus, ozone‐damaged Jeffrey pine needles have a unique spectral signature in relation to dominant needle conditions of ponderosa and Jeffrey pine trees.     

EFAST Method for Global Sensitivity Analysisof Remote Sensing Model’s Parameters

Sensitivity analysis for parameters of remote sensing physical models is a prerequisite for inversion.The EFAST(Extended Fourier Amplitude Sensitivity Test)as a global sensitivity analysis method,can analyze not only a single parameter’s sensitivity but also the coupling effects among parameters.It is usually applied to analyse parameters’ sensitivity of the high-dimensional nonlinear models.In this paper,the SAIL model is taken as an example,the EFAST method and the field measured data of winter wheat in Shunyi district in 2001 were applied to analyze the model parameters’ sensitivity throughout the growing season and in different growth stages respectively.The results are compared with those of the USM (Uncertainty and Sensitivity Matrix) method.The results show that either the EFAST or the USM method for parameters’ sensitivity analysis of the SAIL model is feasible;but the EFAST method,which takes into account of the coupling effects among all the parameters and the analysis result is global,compared to the USM method,is more objective and comprehensive.     

An Improvement of Herbrand＇s Theorem and Its Application to Model Generation Theorem Proving

This paper presents an improvement of Herbrand＇s theorem. We propose a method for specifying a subuniverse of the Herbrand universe of a clause set S for each argument of predicate symbols and function symbols in S. We prove that a clause set S is unsatisfiable if and only if there is a finite unsatisfiable set of ground instances of clauses of S that are derived by only instantiating each variable, which appears as an argument of predicate symbols or function symbols, in S over its corresponding argument＇s sub-universe of the Herbrand universe of S. Because such sub-universes are usually smaller （sometimes considerably） than the Herbrand universe of S, the number of ground instances may decrease considerably in many cases. We present an algorithm for automatically deriving the sub-universes for arguments in a given clause set, and show the correctness of our improvement. Moreover, we introduce an application of our approach to model generation theorem proving for non-range-restricted problems, show the range-restriction transformation algorithm based on our improvement and provide examples on benchmark problems to demonstrate the power of our approach.     

Denotational Semantics of a Simple Model of Eiffel

A simple abstract model of Eiffel is introduced,and its denotational semantics is defined using VDM style.A static analysis approach is presented to treat multiple inheritance and renaming mechanism.Within the framework of denotational semantics introduced in this paper,the key features of Eiffel,such as identification,classification,multiple inheritance,polymorphism and dynamic binding,can be adequately characterized.     

A Parallel Implementation Model of HPARLOG

In this paper,a new parallel logic programming language——HPARLOG developed by usis described,and a new scheme for the AND-parallelism implementation in logic programminglanguage is proposed.This scheme not only resolves the instantiation conflict on sharing-variables,thoroughly explores the parallelism of the programs with incrementally constructeddata structure,but also decreases the dynamic complexity of the programs.In addition,apscudo-copy based memory management scheme to enhance the locality of goal processes andlower the overhead of program execution is proposed.     

Spectral analysis of nonuniformly sampled data – a review

In this paper, we present a comprehensive review of methods for spectral analysis of nonuniformly sampled data. For a given finite set of nonuniformly sampled data, a reasonable way to choose the Nyquist frequency and the resampling time are discussed. The various existing methods for spectral analysis of nonuniform data are grouped and described under four broad categories: methods based on least squares; methods based on interpolation techniques; methods based on slotted resampling; methods based on continuous time models. The performance of the methods under each category is evaluated on simulated data sets. The methods are then classified according to their capabilities to handle different types of spectrum, signal models and sampling patterns. Finally the performance of the different methods is evaluated on two real life nonuniform data sets. Apart from the spectral analysis methods, methods for exact signal reconstruction from nonuniform data are also reviewed.     

Integration of Weights Model of Interval Numbers Comparison Matrix

Consistency and the weights estimation model of the interval number comparison matrix (INCM) in the analytical hierarchy process is studied under uncertainty decision-making case.Based on the weights feasible region,the local consistency definition and the local satisfactory consistency definition are given.Then,a computational model set up to test whether the INCM has the local satisfactory consistency or not.Moreover,the consistency degree based on the random crisp compar- ison matrix is defined as an effective index to test the consistency.Next,the upper range model,the lower range model,and the possible value model are put forward which can solve the problem that some existing approaches do not consider the consistency and its effect on the weights.According to the property of these models,a genetic algorithm is developed.     

An Extension of Chaiken′s Algorithm to B-Spline Curves with Knots in Geometric Progression

Chaiken′s algorithm is a procedure for inserting new knots into uniform quadratic B-spline curves by doubling the control points and taking two successive averages. Lane and Riesenfeld showed that Chaiken′s algorithm extends to uniform B-spline curves of arbitrary degree. By generalizing the notion of successive averaging, we further extend Chaiken′s algorithm to B-spline curves of arbitrary degree for knot sequences in geometric and affine progression.     

A General Architecture Model of CPDL Interpreter

This paper puts forward a general architecture model of CPDL Interpreter,Profiles the logical structure of the modules,and analyses the burden distribution among the interpreter units.The work has significance in developing practical interpreter products.