1,720,992 research outputs found
On the Evaluation of Errors in the Virtual Design of Mechanical Systems
No full textIn this article, the information value is used in numeric analysis as both a method for
data approximation and a measure of data equality among a set of values. To this end, a surface
segmentation, based on a study for constructing a hierarchy for vectors clustering using certain
similarity criteria, is presented. The technique is based on the analysis of vectors representing regions
associated with given types of critical points. An approach based on the Max Entropy in Metric Space
(MEMS) is introduced in the paper, in order to extract a cluster of local features and to obtain an
analysis of mechanical systems in the 2D and/or 3D spaces. The approach proposed in the paper can
be effectively used in virtual prototyping and optimal designing of mechanical systems
Automatic classification of a batch of mechanical products through an application of the Minkowski geometry to image analysis.
No full text
Fuzzy evaluation of temperature distribution in laser sheet metal forming
Full text linkThis paper present a fuzzy inference system for
temperature distribution calculation in single pass
laser forming of a typical aeronautic alloy. Some
experimental and numerical data are used to build
the knowledge of the phenomenon, while other nu-
merical data are used to check the fuzzy system and
to show the precision of the system. The error of
fuzzy calculation is less than 5% while the time cal-
culation drop down compared to thermal FEM cal-
culatio
Design Optimization of a Natural Gas Substation With Intensification of the Energy Cycle
Full text linkAbstract
Design Optimization of a Natural Gas Substation with Intensification of the Energy Cycle
(Arcangelo Pellegrino and Francesco Villecco)
Natural gas is currently the natural substitute of petroleum as an energy source, since the foreseen
ending up of this latter in the next decades. As a matter of fact, natural gas is easier to handle,
less dangerous to be transported, somehow environmentally more friendly. The gas ducts operate
with large flow rates over very long distances at high pressures, which are usually lowered in
proximity of the final substations by lamination valves which, in fact, dissipate energy. However,
a careful management of the pressure reduction may allow an energy recovery while using the gas
expansion to operate a turbine. In this case, gas must be preheated to compensate for the energy
required by the expansion. A proper control of all the parameters involved becomes crucial to an
intelligent use of these resources. In this paper, the possibility of using a pre-heating system has
been examined as a way to intensify the energy cycle in an expansion substation of the city gas
network. Fuzzy logic has been used to optimize the natural gas expansion in a turbine to produce
electrical energy. A fuzzy system has been designed and realized to control the whole process of
gas expansion, from the gas pre-heating to the pressure reduction. The system operates over the
whole year, accounting for the pressure, temperature, and gas flow rate variations experienced in
the gas line. The exit values of the latter and the inlet value of the gas pressure are selected as input
variables, being the output variable the temperature of the pre-heating water at the heat exchanger
inlet
Extracting usable heat from abandoned underground mines: Example of Con Mine, Yellowknife, Canada
No full textFuzzy approach to measures correction on Coordinate Measuring Machines: The case of hole-diameter verification
No full textIn this paper we analyze the capabilities of a routine, based on Fuzzy logic, for elaborating a data set coming from a CMM (Coordinate Measuring Machine). We will show how to obtain, during holes measuring, the best measure, so that the approximation error is minimized. Moreover the CMM on-board software can elaborate these data and select the mathematical representation of the stored data, by identifying quotes, measures, axes, diameters, tolerances and so on. Information on measured parts is usually elaborated by an algorithm based on the least square squared error method, in order to evaluate the good shape of the hole; our purpose is to propose a new kind of approach, based on the Inferential Fuzzy system method, both to reduce the number of measured points, and to obtain the same accuracy. Our approach enables to measure the holes with a number of points lower than those usually needed for the CMM software. Thus time spent for obtaining a good measure is significantly reduced
Entropic Measure of Epistemic Uncertainties in Multibody System Models by Axiomatic Design
No full textIn this paper, the use of the MaxInf Principle in real optimization problems is investigated for engineering applications, where the current design solution is actually an engineering approximation. In industrial manufacturing, multibody system simulations can be used to develop new machines and mechanisms by using virtual prototyping, where an axiomatic design can be employed to analyze the independence of elements and the complexity of connections forming a general mechanical system. In the classic theories of Fisher and Wiener-Shannon, the idea of information is a measure of only probabilistic and repetitive events. However, this idea is broader than the probability alone field. Thus, the Wiener-Shannon’s axioms can be extended to non-probabilistic events and it is possible to introduce a theory of information for non-repetitive events as a measure of the reliability of data for complex mechanical systems. To this end, one can devise engineering solutions consistent with the values of the design constraints analyzing the complexity of the relation matrix and using the idea of information in the metric space. The final solution gives the entropic measure of epistemic uncertainties which can be used in multibody system models, analyzed with an axiomatic design
Evaluation of Uncertainties in the Design Process of Complex Mechanical Systems
No full textIn this paper, the problem of the evaluation of the uncertainties that originate in the complex design process of a new system is analyzed, paying particular attention to multibody mechanical systems. To this end, the Wiener-Shannon’s axioms are extended to non-probabilistic events and a theory of information for non-repetitive events is used as a measure of the reliability of data. The selection of the solutions consistent with the values of the design constraints is performed by analyzing the complexity of the relation matrix and using the idea of information in the metric space. Comparing the alternatives in terms of the amount of entropy resulting from the various distribution, this method is capable of finding the optimal solution that can be obtained with the available resources. In the paper, the algorithmic steps of the proposed method are discussed and an illustrative numerical example is provided
Measuring the comfort level of a driver by means of biomedical objective parameters. Preliminary results.
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