One of the most important problems in training the students to computer science (CS) is a selection of suitable platform: first of all operating system and lingware.
The discussion about what is better (Windows or UNIX, C++ or Pascal etc.) obviously will not be finished in the nearest future or even never. So let us consider the problem from the other point of view. Is it possible to determine the set of main properties and features of computer system that makes it almost ideal for CS studying? Let's formulate some obvious requirements for such “ideal” system.
Maximal integrality, i.e. the absence of disparate subsystems on the different levels: informational, linguistic etc.
Nonformally – simplicity and clarity and formally – mathematical purity of the basic computational model (paradigm).
The opportunity of simulating the different CS objects and technologies on the base of integrated environment.
The list could be continued.
On the basis of the analysis of almost all modern platforms the conclusion was made that Lisp system is a main candidate to satisfy the above requirements. But it is well known that there are many different dialects and realizations of Lisp. So we need to choose among them now.
We believe the most appropriate dialect/realization of Lisp is Scheme from MIT. Moreover, at MIT it was developed a very popular CS course Structure and Interpretation of Computer Programs. Nevertheless at the department of Information Technology and Computer Systems of our university it was designed and partially realized the origin Lisp system CILisp (Compact Instrumental Lisp). CILisp is extremely compact Lisp dialect with many additional features. By the means of special system controls it is possible to customize CILisp for the concrete purpose. We can easily change the type of scoping and evaluation, use different computational paradigms (pure applicative, imperative, object-oriented etc.) and much more.
A.Y.Ismailov, R.N.Allakhverdiyev TO THE OPTIMAL PARAMETER SEARCH PROBLEM IN AUTOMATED DYNAMIC SYSTEM (PLANNING)
The specific features of the optimal parameter search problem in automated dynamic system planning are nonlinear character of the applied and large amount of variables and limitation meters search these features require to use either stochastic optimization method based on stochastic approximation and causal search or on their combination.
Optimization method improvement as determined so as stochastic bring to private algorithm adapted to solve this or that kind of sums. Nowadays there is no better effective universal algorithm for solving any class optimization sum in every respect. In this connection problems related to effective method choice for solving concrete optimization sums arise in practical activity (in practice). For successful solution (discussion) of different optimization sums it is necessary to create packet including the library of a number of different programs.
The problem of atomized method choice must be carried out in two regimes-in packet (primarily-by all means) and in dialogues.
Optimal solution search can be realized in packet regime when the used methods sequence is defined and their parameters are given. Such aplaptation, i.e. its control system must have possibility for independent better choice of given optimization program and transferring to another procedures while solution process. Atomized packet creation principles of optimization procedures for determined sums solution are described in many works. For automation of stochastic optimization effective algorithm choice in stochastic system designing it is necessary to separate sums class according to the following main signs:
- optimization sum type (conditional or absolute).
- required solution exactness.
- time necessary for aim function value getting.
- controllable parameter number.
- local optimum presence or absence.
- casual obstacle size and its law of change (variability).
- initial search point distance from the true optimum point.
- presence absence of correlation between parameters.
Further it is reliable to do calculations in dialogue regime when the user during the calculation, following (watching) after intermediate results, changes the 1) algorithm, realizes purposeful transfer from one method to another, takes part in sums solution simultaneously if necessary, 2) parameters and so on.
Such kind of work regime requires the intuitive engineer’s calculator’s approach use and gained experience as well.
Stochastic optimization algorithm realized in packet and some numerical experiments results in computer are given in this report. It should be mentioned that such packet must take into consideration addition chance of new effective algorithm optimization.
The perspective class of control processors is considered, in the basis of which organization the associative control storage is fixed. The parallel processors of handle have the improved characteristics in difference from processors based on the constants storage devices: by large speed and smaller sizes of the control storage.
The interactive designing includes the following stages.
At an algorithmic stage the task of representation of the control algorithm in the associative - orient form as the parallel network scheme of algorithm (PNSA) is decided. PNSA is the digraph with three types of tops: processings, multisequencing and junction. The arcs of the graph are loaded with the generalized if statements.
It is offered to prove a semantic correctness PNSA by translation PNSA in a Petri Net with the consequent definition it of properties . PNSA is correct (i.e. is finite and is determined), if appropriate to it Petri Net is alive and is safe.
At a structural stage the offered structures of controlprocessors with associative organization of the control storage are considered. The sample in a character part of the associative control storage is made in parallel on bits and words. The analysis of offered structures of associative processors of the control constructed on centralized, decentralized and disrtibuted principle of control is conducted. In considered structures to stream of commands the generalized if statements, and dataflow - composite operators of assignment are put in correspondence.
At a logical stage depending on features of the control algorithm and logical basis the processors of control with unitary coding of states, with substitution of variables, with functional overlapping of the network scheme of algorithm, with internal masking of the generalized if statement, with economic storage of codes of masks are considered.
The indicated stages are realized as the system of automated designing developed on Computer engineering department in Ulyanovsk state technical university.
1. Borisov V. The Algorithmic and linguistic bases of automation of designing of associative parallel control processors // Information systems and technology./ Ulyanovsk state technical university. Ulyanovsk 1998. p. 83.