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The problem of handling imprecision, vagueness and uncertainty in data has been attempted for a long time by philosophers, logicians and mathematicians. Recently there have been many approaches explored to understand and manipulate the imprecise knowledge. The most successful one is fuzzy set theory proposed by Zadeh. The theory of Rough set is a relatively new mathematical approach to decision making...
In multi-zone areas, where the boundaries change with time, it is desirable to place sensors in such a way that the boundary is covered at all times. In this paper, we describe the optimal sensor placement with this property. In this optimal placement, sensors are placed along a see-saw trajectory going between the current location of the boundary and its farthest future location.
The rough fuzzy sets (RFS) is a combination granular computing model with rough sets and fuzzy sets. Its uncertainty includes roughess, rough entropy, fuzziness and fuzzy entropy, etc.. In this paper, the changes of roughness, cut-set and fuzziness are discussed according to the knowledge granularity in different knowledge granularity levels in apporiximation spaces of rough fuzzy sets. Hence, the...
Scaling phenomena can be found in a variety of physical situations, ranging from applications in hydrology to communication traffic measurements. This paper focuses on quantiles estimation for a self-similar time series and in particular on the uncertainty that affects their estimates. Quantiles provide in fact additional information about the distribution of the measurements and in certain cases...
This paper defines a new parameter for describing the uncertainty of rough sets. Different from the roughness of a rough set, a global roughness measures the uncertainty of rough sets with respect to the entire information system. This is essential especially for a special rough set - boundary rough sets.We give the definition of global roughness of approximation and boundary rough sets, and analyse...
The inherent uncertainty in RFID signals requires an RFID middleware system to clean the input data after capturing. Typically these systems employ a low pass filter for reducing errors. In this paper we propose an approach for data cleaning that exploits basic characteristics of RF signals as well as maximum likelihood operations. With our filter we improve proximity detection of RFID tags. Our solution...
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