Probabilistic optimization of the measurement and data interpretation of electromagnetic field strength
In an era in which exposure to electromagnetic radiation from various electric/electronic machinery and devices is more and more intense, measuring the strength of the electromagnetic field (EMF) in relation with the maximal values allowed has become as important as monitoring the quality of air or water.
Although the market offers a wide range of EMF measuring devices, and many companies provide measurements on request, neither the individual nor the mediated measurements are executed correctly or adequately. The technical-constructive features of the devices make the measured values dependent upon the spatiality of the monitored source, the positioning of the sensor head, and the bandwidth frequency of the source.
As concerns the interpretation of the measured data, the simple fit of a value within an interval of allowed values found in the tables provided by ICNIRP is not always relevant. Interpretation through the direct fit within a table of values is relevant when we monitor each detectable source individually, but when we consider an environmental measurement concerning the cumulated effect of several sources, such a simplistic fit loses relevance. Even if every source has its field parameters within the allowed limits in the measured point, this does not mean that the cumulated effect at the simultaneous exposure in the same point is within the allowed limits. Moreover, some sources are not detectable due to the frequency range within which the meter's sensor operates (the real situation), and therefore an adequate interpretation is much more complex, requiring the theoretic contribution of applied mathematics.
The project aims to optimize the process of measurement and interpretation of the EMF strength, by providing an optimal algorithm for interpretation of the measured data (in relation with the maximal values allowed published by ICNIRP). Such an algorithm should be applied to the measurements in proximity to sources, but especially to the environmental measurements aiming to assess the cumulated effect of the radiation, under the condition that not all of the sources are observable or detectable (with unknown frequencies).
Because the result of an environmental measurement was usually interpreted (erroneously) in an absolute mode by comparing the value with the allowed values and ignoring the multitude of sources of various frequencies, a mathematical algorithm was necessary for the adequate interpretation of these measurements.
We have obtained an algorithm of measurement and interpretation that uses all the information provided by the measurement as well as information specific to the monitored location. The algorithm is synthesized and edited in a ready-to-use form for the measuring operator. The assessment of the cumulated effect of the radiation in conditions of uncertainty is done by assigning probability labels in a probability field created on the basis of available information.
In brief, we have estimated a probability for the sum (where is the strength of the electric field of source number j, and is the maximal value allowed for the strength of the electric field of the same source) to be either subunitary or supraunitary (the general criterion of fitting or not fitting into the interval of allowed values for the cumulated effect of several sources); that probability depends on certain particular conditions of the monitored location and is defined on the basis of the following idealizations necessary for establishing the probability field: the uniform distribution of the RF or LF sources of any location over the entire bandwidth frequency and a certain proportion of the RF and LF sources for each type of location. The final interpretation algorithm assigns to each measured value and type of location a specific probability label (vey low, low, high, very high) and is edited in a ready-to-apply form.
Dr. Catalin Barboianu (Applied mathematics), principal investigator
Dr. Theodor Florica (Electronic Engineering)
The research phase of the project has completed and we are in the phase of preparing the documentation for the industrial use.