Engineering science / 12. Automated control the system on a production

Kulyk A.J., Krivogubtchenko D.S., Kulyk A.A.

Vinnitsa national technical university, Ukraine

Optimization of process of exchange information

in the computer systems

 

Basic parameters which influence on the transmission process and which can be varied is:

§        power of signal of transmitter Рс.пер, to regulate which simpler all;

§        speed of transmission υ, the change of which though needs certain charges, but special technical complexities does not cause;

§        length of code combination nkod which is determined the chosen method of code and amount of errors which are determined and corrected. The change of this parameter requires the change of algorithm of previous preparation of information;

§        a coefficient kυ, the value of which is characterized principle of construction of signal of transmitter (by a presence and duration of pauses between informing signals). The correction of this parameter requires the change of forming algorithm of signal a software-based, hardware-based or combined way [1 – 3].

The transmission of information by the communication channel it is possible not only separate bytes but also blocks, long Nb bytes. Then, the index of quality of information transmission depends a communication by channel Ek on composition of signal vector  which is transmitted, probability of distortion of the elementary signal р0, block length which is transmitted, Nb and amount of errors which are corrected, t. Thus, the task of construction of code can be formulated in a kind:

 

,                                         (1)

where  – transmission speed of the information;

рk – probability of correct acceptance of block Nb data bytes;

рпор – threshold probability of correct acceptance of block Nb data bytes;

υk – speed of information transmission by a communication channel;

υпор – threshold speed of information transmission by a communication channel;

Т – time of transmission the block Nb data bytes,

 

taking into account the maximum value of volume of signal Vk £ Vnop .

For the second case index of quality of the information transmission by a communication channel Ek depends on composition of the signal vector  which is transmitted, probability of distortion of the elementary signal  р0, size of block which is transmitted, Nb and amount of repetitions r. Thus, the task of construction of code can be formulated in a kind

 

,                                      (2)

 

thus in both cases threshold speed of information transmission is determined after the Shannon methodic [4].

Mathematical models which bind probability of authentication of informing signal to ratio signal/noise, and mathematical models which allow to define the maximal value of effective speed of transmission for the real terms, method and code parameters are got  [5 –  8]. It characterizes local optimums of objective function which describes the process of information transmission. If as an index of quality of the information transmission by a channel Ek take the volume of signal, its minimization on condition of providing of necessary veracity of exchange information fully answers both a purpose and conducted researches. Coming from it, objective function (1) and (2) it is possible to give in a kind:

 

 .                                              (3)

 

The condition F = const shows that the bar of frequencies for forming of communication channel is determined normatively and can not change, and power of signal of transmitter Рс.пер can not exceed a maximum value for providing of capacity of the system on the whole. Speed of information transmission  also must not exceed a maximum value which is determined by the cycle of manipulation of information on a receiver.

At the use of methods (n, k)-coding volume of signal Vc is possible to define as

 

.          (4)

 

Minimization of form (4) at implementation of the formulated limitations allows to define the optimum mode of exchange information at the real terms of connection. Passing to the logarithmic axes of coordinates,

 

,          (5)

 

task of search of a minimum of volume of signal Vc can be erected to the task of the linear programming, which simply enough gets untied by a simplex method [9].

Like the volume of signal can be defined and for the terms of the majority decoding

 

.          (6)

 

And in this case the task of optimization can be erected to the decision the task of the linear programming by a simplex method

 

.                      (7)

 

Thus, higher ratio and algorithms of adaptation is got fully acceptable to achievement of optimum terms of information transmission and realization both parametric and structural- algorithmic optimizations.

 

References.

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