Atomic Memory Model
Memory leaks and overruns, Memory abstraction.
The task to track down and remove memory leaks is known as one of the most tedious and unpleasant ones that a software engineer might encounter. In some cases once part of a program memory leaks it might become impossible to remove. Buffer overruns are another problem often even more difficult and unpleasant to solve. This paper suggests an effective way to eradicate the above issues and other problems related to memory in a computer program. This is achieved by enforcing a preemptive methodology for memory handling in addition to abstraction of the memory and representing it as encapsulated entity with three properties: class, semantics and origin. The Atomic Memory Model is a consistent and elegant methodology as opposed to garbage collecting. It significantly improves the quality of code making most of the issues related to memory intrinsically impossible to occur and increasing the speed and ease of development.
Fast Median Filtering Based on Bucket Sort
A. Bosakova-Ardenska, S. Stoichev, N. Vasilev, E. Stoicheva
Median filtering; bucket sort; parallel algorithm; MPI.
This paper presents two algorithms for median filtering of images. These algorithms are based on the bucket sort algorithm. A comparison is made between our two algorithms and an algorithm proposed Thomas Huang, George Yang and Gregory Tang. They offer an algorithm that uses partial histograms for median filtering of images. It is made a comparison between the sequential and parallel implementation of our algorithms on one side and Huang, Yang and Tang’s algorithm on the other. For parallel implementation of algorithms we use MPI (Message Passing Interface). For execution of parallel programs a cluster of 4 computer systems is used.
Design of Compound Hyperchaotic System with Application in Secure Data Transmission Systems
Lyapunov exponent; hyperchaotic systems; chaotic synchronization; chaotic switching.
In this paper an approach for designing hyperchaotic systems with two or more positive Lyapunov exponents on the basis of low-order chaotic models is proposed. The motivation is that hyperchaotic systems are preferable for use in chaotic data protection systems due to their more complex behaviour, but very few such models are known. The proposed hyperchaotic system is based on the Van der Pol Duffing third-order chaotic model. After proving that the designed system is hyperchaotic, a stable synchronization scheme between two such systems is proposed. To facilitate the stability analysis, a novel linear-nolinear decomposition synchronization approach is used. A chaotic switching secure data transmission system is projected on the basis of the proposed hyperchaotic system. The simulation experiments with a binary data signal show, that the signal can be reliably protected, when it is masked with a hyperchaotic signal on its way from the transmitter to the receiver.
Robust Control of a Distributed Parameter System
Induction heating; Maxwell equation; heat transfer; robust control system.
This article presents, at the outset, a mathematical model of the electromagnetic and thermal processes in a body, subjected to induction heating. Next follows a route for designing a robust controller that will provide a uniform heating mode for the body. The electromagnetic analysis carried out initially establishes the density of the thermal source that participates later in a thermal boundary problem. The finite element method (FEM or FE method) is utilized for the thermal problem solution and the analysis reduces to a system of linear ordinary differential equations (ODEs). Thus it is possible, to apply the control theory and the Robust Control Toolbox in MATLAB, with the aim of devising a m-controller that ensures a mode of min radial temperature gradient deviation (i.e. a uniform heating mode). It is well-known that such modes are necessary for processes like semi-solid forming and hot casting where the primary objective is the provision of a max uniform heating for a min of time.
Protein Structure Comparison Methods
Protein structure comparison; models; comparison algorithms; similarity measure
Existing methods for protein structure comparison are examined and their basic properties are presented. Analysis of the methods is made, which is based on their three major components model of the structure, comparison algorithm and similarity measure. Each method is evaluated according some criteria, which include the level of representation and the way of service of the model, the complexity and strategy of the comparison algorithm and how meaningful the similarity measure is. The methods are grouped according these criteria. Advantages and disadvantages of all groups are discussed in aspect to their application for solving different type of problems in contemporary structural biology.