An overview of methods of actual signal period time (and instantaneous signal frequency) measurement is presented, and the methods are compared from the point of view of achievable accuracy, sensitivity to noise, higher order harmonic components and computational complexity. Importance of T (or f) estimation is pointed out.

Since aluminium’s relative density is only about one – third of that of steel or of a copper-base alloy, it is widely used in automotive, constructional engineering, electrical applications and mechanical equipment as in the forms of alloys containing small amounts of other elements. The main aim in the present work is to investigate the effect of copper addition at 2 % intervals starting from 2 % to 8 % on the corrosion resistance and hardness of Al – Cu alloys. It can be concluded from the results of the present work that the corrosion resistance of Al-Cu alloys was observed to show great variety depending on corrosion media. The copper addition was found to play a vital role in influencing the microstructure and improving the hardness of both heat treatable and 60 % rolled alloys.

The contribution proposes an expert system for optimization of cutting parameters from commercial data bases. The expert system OPTIS serves for optimization of cutting conditions with respect to minimizing the manufacturing costs by taking into account the cutting process limitations. The programme is applicable only for turning. The OPTIS selects optimal cutting conditions with respect to the tool maker, workpiece material, type of machining, machine, smallest and greatest cutting conditions, tool, data on series, type of clamping and workpiece geometry.

In this paper a method is proposed to assist the designer of a measurement system in finding the optimal set of sensors for a given measurement problem. The method will be implemented on a computer system and will contain a framework for optimality, where the user can define, what is optimal in his/her case.
To combat the combinatorial explosion during a search, solutions will be generated on different levels of abstraction. A solution at a high level of abstraction represents a large number of solutions at a lower level. Making choices by cutting possibilities at this high level will therefore enable to go through the search-tree in an efficient way.
Criteria with respect to the performance and costs of the solutions are discussed, together with methods to weigh different criteria against each other.
The user interface should enable the user to formulate his measurement problem. This means in our view that a model must be generated of relevant aspects of the scene, in which the measurement problem occurs. Finding a solution to the measurement problem then means the design of an environment in which a measurement can be done that determines the measurand.

Traffic control requires measuring of road traffic parameters and vehicle parameters (velocity, length, number of vehicle, time distance between vehicles, etc.). One of very important parameters is the class of a vehicle. Up to date, videocamera systems, system with loop sensors, etc., have been used for classification. Unfortunately, the vehicle pattern were very complicated (picture from camera, time signal from loop, ...). Classification depends on the comparison of an actual signal to the reference pattern. It was very time-consuming and needed remembering the large reference pattern. This paper deals with a new method of vehicle classification. We have proposed the conversion of the measured signal into a vector of numerical parameters (only a few). The vehicle classification is being made by the comparison of such a very short vector with the vectors containing the values of parameters typical for the chosen class of a vehicle. Tests have been made on streets of Cracow (Poland). The classification efficiency for four predetermined vehicle classes is between 77% and 95%.