DEVELOPMENT OF THEORETICAL FUNDAMENTALS OF OPTIMIZATION AND QUALITY ASSESSMENT OF TRACTION ROLLING STOCK MANAGEMENT

Among the main causes of human operator errors are the following: unsatisfactory training or low level of qualification; non-compliance with the prescribed operating procedures; unsatisfactory working conditions associated with such negative phenomena as excessive noise, vibration, temperature fluctuations in the driver's cab (especially on locomotives); lack of attractive incentives to achieve the optimal level of quality of work. The choice of the criterion of optimal control can be ambiguous. The source of complexity is the inconsistency of goals. If you want to optimize one of the parameters in compliance with the restrictive requirements for other parameters, then a partial criterion is formed. In the presence of several optimality criteria, the additive criterion is chosen when the absolute values of the criteria are significant for the selected parameter vector. If a significant role is played by changes in absolute values of partial criteria in the variation of the vector of variables, then apply the multiplicative criterion of optimality. If the task is to achieve equality of normalized values of conflicting partial criteria, then the optimal design is performed by the minimum criterion.

COMPLEX EVALUATION OF EFFICIENCY OF ECONOMICAL ACTIVITIES IN CONSTRUCTION ENTERPRISES/STATYBOS ĮMONIŲ KOMERCINĖS-ŪKINĖS VEIKLOS EFEKTYVUMO KOMPLEKSINIS ĮVERTINIMAS

The means used at the present time for a complex evaluation of the efficiency of building enterprise activities are either oversimplified or too complicated. Therefore it is necessary to develop for practical needs convenient, simple and understandable means. The problem can be solved by methods based on a graphical-analytical interpretation. Among the comparatively simple means applied now for a complex evaluation are: by the sum of work places; evaluation based on a geometrical average; evaluation based on the sum of partial indices, etc. More complicated means include the multi-criteria complex proportional evaluation, etc. In case of the suggested graphical-analytical complex evaluation, different charts may be used, including pie charts. Three dimensions differ in them: partial indices, the corresponding central angles and the circle radius. There exist some cases of graphical-analytical evaluation. In the first case, the circle area in divided into n sectors, the area of each sector being equal to the value of a corresponding partial criterion. In the second case, the circle is also divided into n sectors. The radius of each sector equals the value of a corresponding partial index. The generalised index is equal to the sum of all sector areas, too. In the third case, the radii of all sectors are the same and their angles are proportional to the values of partial angles of each sector. After connecting by a line the points got in that way, a figure is obtained which describes the corresponding criterion. The sum of areas of all such figures reflects the value searched for. In all three cases the importance of partial indices can be estimated additionally. The calculations performed according to all existing and suggested cases have shown that the means for graphical-analytical complex evaluation are precise and can be applied in everyday activities.

On the Optimal Location and Number of Intercoolers in a Real Compression Process

In this paper the optimal location and number of intercoolers in a real compression process, including pressure losses, is derived by minimizing the compression specific work. Consequently the series of intermediate pressure values where the system intercoolers should be located is evaluated. As a result a solution different from the classical-isothermal compression process is obtained. The ideal process is evaluated and verified as a particular case by assuming no pressure losses. In reality, minimizing the compression work is only a partial criterion of optimization and the final decision regarding the optimal number of intercoolers should be obtained by using techno-economic criteria.