9762 papers found
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.
As well known air quality changes can be predicted by mathematical models, like roll back models, empirical models, and dispersion models; or by physical models, like ”wind tunnel” and analogous water models of simulation, or using "on situ" experiments with tracers. Mathematical models are more important in order to test and to predict pollutant effects in a given area. The aim of this work is to build effective models for atmospheric and industrial pollution to be predicted by using a Pair Comparison Technique (PCT). Experiments have been carrying out with laser-mode-switching equipment to...
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...
Fluid flow measurements are probably the most important of all existing measurements in process engineering. Selection of an optimal flowmeter is a difficult task. According to the quantity of knowledge available, a computer program for selection of an optimal flowmeter seems to offer a solution for this problem. For a detailed flowmeter selection procedure, around fifty variables were identified as the most important factors in selection. They were then grouped into five general areas: performance, fluid property, installation, environment and economy. A database for fourteen different...
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.
Expert Systems are based on capturing the corresponding expertise from the human experts and conveying it into a computer through a knowledge base. A knowledge base is a collection of logical propositions whose relationships model the knowledge about a certain topic. In this paper the principal issues to be taken into account to apply successfully the Expert Systems technology to decision making in engineering are discussed.
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...
At present avery perspective solution of indications classification in the defectoscopy is neural network application. One of the fields is classification of indications into classes, that are characterized by the signal shape, eventually by the signatures relating to the signal shape. The nondestructive defectoscopy of steam generator tubes of nuclear power plants by multifrequency eddy current method is the field, in that the use of classifiers, based on neural network is very perspective. The contribution concentrates on the choice of suitable neural network structures, on the choice of...
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....
There had been suggested a new method of estimating works of art by experts, based on fuzzy sets usage and simulation in the fields of linguistic variable. The methods of examination formalization and the algorithm of receiving estimations of four canvases by a group of three experts had been also worked out.