DSpace Collection: Volume 3 Number 4
http://hdl.handle.net/10525/1489
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Development and Implementation of NURBS Models of Quadratic Curves and Surfaces
http://hdl.handle.net/10525/1574
Title: Development and Implementation of NURBS Models of Quadratic Curves and Surfaces<br/><br/>Authors: G. Petkov, Emiliyan<br/><br/>Abstract: This article goes into the development of NURBS models ofquadratic curves and surfaces. Curves and surfaces which could be represented by one general equation (one for the curves and one for the surfaces) areaddressed. The research examines the curves: ellipse, parabola and hyperbola, the surfaces: ellipsoid, paraboloid, hyperboloid, double hyperboloid,hyperbolic paraboloid and cone, and the cylinders: elliptic, parabolic andhyperbolic. Many real objects which have to be modeled in 3D applicationspossess specific features. Because of this these geometric objects have beenchosen. Using the NURBS models presented here, specialized software modules (plug-ins) have been developed for a 3D graphic system. An analysis of their implementation and the primitives they create has been performed.Thu, 01 Jan 2009 00:00:00 GMTOperational Methods in the Environment of a Computer Algebra System
http://hdl.handle.net/10525/1573
Title: Operational Methods in the Environment of a Computer Algebra System<br/><br/>Authors: Spiridonova, Margarita<br/><br/>Abstract: The presented research is related to the operational calculusapproach and its representative applications. Operational methods are considered,as well as their program implementation using the computer algebrasystem Mathematica. The Heaviside algorithm for solving Cauchy’s problemsfor linear ordinary differential equations with constant coefficients isconsidered in the context of the Heaviside-Mikusinski operational calculus.The program implementation of the algorithm is described and illustrativeexamples are given. An extension of the Heaviside algorithm, developed by I. Dimovski and S. Grozdev, is used for finding periodic solutions oflinear ordinary differential equations with constant coefficients both in thenon-resonance and in the resonance cases. The features of its program implementationare described and examples are given. An operational methodfor solving local and nonlocal boundary value problems for some equationsof the mathematical physics (the heat equation, the wave equation and theequation of a free supported beam) is developed and the capabilities of thecorresponding program packages for solving those problems are described.A comparison with other methods for solving the same types of problems isincluded and the advantages of the operational methods are marked.<br/><br/>Description: This article presents the principal results of the doctoral thesis “Direct Operational Methodsin the Environment of a Computer Algebra System” by Margarita Spiridonova (Institute ofmathematics and Informatics, BAS), successfully defended before the Specialised AcademicCouncil for Informatics and Mathematical Modelling on 23 March, 2009.Thu, 01 Jan 2009 00:00:00 GMTOn some Modifications of the Nekrassov Method for Numerical Solution of Linear Systems of Equations
http://hdl.handle.net/10525/1572
Title: On some Modifications of the Nekrassov Method for Numerical Solution of Linear Systems of Equations<br/><br/>Authors: Iliev, Anton; Kyurkchiev, Nikolay; Petkov, Milko<br/><br/>Abstract: A modification of the Nekrassov method for finding a solutionof a linear system of algebraic equations is given and a numerical exampleis shown.Thu, 01 Jan 2009 00:00:00 GMTComputing with the Square Root of NOT
http://hdl.handle.net/10525/1571
Title: Computing with the Square Root of NOT<br/><br/>Authors: De Vos, Alexis; De Beule, Jan; Storme, Leo<br/><br/>Abstract: To the two classical reversible 1-bit logic gates, i.e. the identitygate (a.k.a. the follower) and the NOT gate (a.k.a. the inverter), we add anextra gate, the square root of NOT. Similarly, we add to the 24 classical reversible 2-bit circuits, both the square root of NOT and the controlled squareroot of NOT. This leads to a new kind of calculus, situated between classicalreversible computing and quantum computing.Thu, 01 Jan 2009 00:00:00 GMTClassification Trees as a Technique for Creating Anomaly-Based Intrusion Detection Systems
http://hdl.handle.net/10525/1570
Title: Classification Trees as a Technique for Creating Anomaly-Based Intrusion Detection Systems<br/><br/>Authors: Jecheva, Veselina; Nikolova, Evgeniya<br/><br/>Abstract: Intrusion detection is a critical component of security information systems. The intrusion detection process attempts to detect maliciousattacks by examining various data collected during processes on the protected system. This paper examines the anomaly-based intrusion detectionbased on sequences of system calls. The point is to construct a model thatdescribes normal or acceptable system activity using the classification treesapproach. The created database is utilized as a basis for distinguishing theintrusive activity from the legal one using string metric algorithms. Themajor results of the implemented simulation experiments are presented anddiscussed as well.Thu, 01 Jan 2009 00:00:00 GMT