Journal:Informatica
Volume 6, Issue 1 (1995), pp. 35–60
Abstract
In this paper we consider the problem of the distributed deadlock resolution. Starting from a high level specification of the problem and the resolution algorithm for a system with single request model, we provide successive levels of decreasing abstraction of the initial specification in order to achieve a solution in a complete distributed system. The successive refinements and the final distributed deadlock resolution algorithm are formaly described and proved by using the Input-Output Automata Model. The proposed solution is a modification of the algorithms in Mitchell and Merritt (1984) and Gonzalez de Mendívil et al. (1993) and preserves a similar message traffic to resolve a deadlock.
Journal:Informatica
Volume 6, Issue 1 (1995), pp. 15–33
Abstract
This paper deals with mathematical modelling of diabetes mellitus. A recent classification of diabetes mellitus is given and a new approach in constructing a mathematical model of this disease is described. The aim of mathematical modelling is to help a patient and his doctor in management of diabetes. The algorithms for solving inverse problems of coefficients reconstruction are investigated. Results of computational experiments are given.
Journal:Informatica
Volume 6, Issue 1 (1995), pp. 3–14
Abstract
Control laws' design strategies are developed to stabilize a class of BIBO integro-differential systems with two distributed delays by using an extended system.
Journal:Informatica
Volume 5, Issues 3-4 (1994), pp. 439–451
Abstract
In this paper optimization aspects relatively to circuit component placement problem for gate array VLSI are discussed. Practical and theoretical aspects of the methods of component placement are concerned as well. Effective heuristic algorithms for the initial placement and iterative placement improvement are described. An original strategy of global placement optimization is investigated. Some experimental results based on an automatic placement subsystem for gate arrays – AUTOPLACE developed at Department of Practical Informatics of Kaunas University of Technology are presented.
Journal:Informatica
Volume 5, Issues 3-4 (1994), pp. 414–438
Abstract
The restoration of an entire epicortical ECoG-potential pattern from spatially sampled EEG-potentials can be performed according to the general principle of inverse spatial filtering: if a forward spatial filter is an averaging one, then a mutually inverse spatial filter can form a sharpened pattern from a slurred sampled pattern thus restoring more or less a spatial contrast of a primary source pattern. Brain coverings are the averaging forward spatial time-lag free filter in the transformation “eECoG $\longrightarrow$ EEG”; several models have been already developed for calculating the weight coefficients of this filter. Proposed here method to obtain weight coefficients of the mutually inverse spatial time-lag free filter of EEG is based on the generalized inversion of forward filter's weight coefficients matrix. The developed algorithm is verified using 3-dimensional depiction of numerically simulated patterns: the “real” eECoGs are visually compared with the restored eECoGs, that were obtained from the corresponding spatial samples of the “real” EEGs.
Journal:Informatica
Volume 5, Issues 3-4 (1994), pp. 385–413
Abstract
This paper establishes sufficient conditions for stability of linear and time-invariant delay differential systems including their various usual subclasses (i.e., point, distributed and mixed point-distributed delay systems). Sufficient conditions for stability are obtained in terms of the Schur's complement of operators and the frequency domain Lyapunov equation. The basic idea in the analysis consists in the use of modified Laplace operators which split the characteristic equation into two separate multiplicative factors whose roots characterize the system stability. The method allows a simple derivation of stabilizing control laws.
Journal:Informatica
Volume 5, Issues 3-4 (1994), pp. 373–384
Abstract
The problem associated with the stiff ordinary differential equation (ODE) systems in parallel processing is that the calculus can not be started simultaneously on many processors with an explicit formula. The proposed algorithm is constructed for a special classes of stiff ODE, those of the form y′(t)=A(t)y(t)+g(t). It has a high efficiency in the implementation on a distributed memory multiprocessor when the ODEs function has many components. The approximation error is equal to that produced by the analogous sequential algorithm.
Journal:Informatica
Volume 5, Issues 3-4 (1994), pp. 364–372
Abstract
We consider finite population slotted ALOHA where each of n terminals has its own transmission probability pi. Given the overall traffic load λ, the probabilities pi are determined in such a way as to maximize throughput. This is achieved by solving a constrained optimization problem. The results of Abramson (1970) are obtained as a special case. Our recent results are improved (Mathar and Žilinskas, 1993).
Journal:Informatica
Volume 5, Issues 3-4 (1994), pp. 351–363
Abstract
The structure of a multimicroprocessor systems (MS) of M microprocessors (MP) and N blocks of random access memory (RAM) is presented. Probability techniques were applied to compile mathematical models which reflect random processes both in the whole structure and in its surroundings, as well as the links in the system units, specific operation features of the MP and the different data flows.
An analysis indicates that by simulations of MS in the preliminary and in the engineering stages of their design, when their behavior can be related to arbitrary parameters, universal evaluations of their operation can be achieved, lots of time, finance and human efforts can be saved.