This paper examines a downlink transmit beamforming scheme recently proposed in [1]. The idea is based on the use of an adaptive channel estimator at the base-station and requires the mobile to selectively feed back the value of the prediction error. This paper proposes a joint maximum-likelihood and set-membership filtering algorithm for adaptive channel estimation that provides robustness aga...

Many science and engineering applications feature non-convex optimization problems where the objective function can not be handled analytically, i.e. it is a black box. Examples include design via experiments, or costly finite elements simulations. To solve these problems, global routines are used. These iterative techniques must trade-off exploitation close to current best point with explorati...

The present study considers a fuzzy color system in which triangular pyramid-like membership functions are constructed on the RGB color triangle. This system can process a fuzzy input to an RGB system and output the center of gravity of three weights associated with respective grades. Triangular pyramid-like membership functions are applied to the RGB color triangle relationship. By treating th...

In many practical situations, we only know the bounds on the distances. A natural question is: knowing these bounds, can we check whether there exists a metric whose distance always lie within these bounds – or such a metric is not possible and thus, the bounds are inconsistent. In this paper, we provide an answer to this question. We also describe possible applications of this result to a desc...

The original aim of this research was the introduction of a compositive measure of information (see e.g. [5]) on a class (an algebra) of fuzzy subsets of an universe f2. However, there is a bijection between the class of compositive informations and the class of decomposable measures (see e.g. [2]). Therefore, we restated our problem as the one of the construction of a decomposable measure over...

In symbolic data analysis, high granularity of information may lead to rules based on a few cases only for which there is no evidence that they are not due to random choice, and thus have a doubtful validity. We suggest a simple way to improve the statistical strength of rules obtained by rough set data analysis by identifying attribute values and investigating the resulting information system....

The fuzzy sets defining the linguistic variable values can be seen as a fuzzy partition of the linguistic variable. The membership functions obtained using fuzzy clustering algorithms are defined with respect to the group prototypes, and they cannot be used to define the linguistic variable values. We introduce several criteria to pass from the clustering membership functions to the linguistic ...