摘要:
A method for determining an error estimate concerning a target device's location. The target device moves and communicates in a wireless environment using signals having at least one measurable signal value. A probabilistic model of the wireless environment indicates a probability distribution for signal values at several sample points in the wireless environment. A set of observations of signal values is made and the target device's location is estimated based on the probabilistic model and the set of observations. The error estimate is determined as a combination of products over several sample points. Each product comprises a probability distribution for the sample point in question being the target device's location and a distance function between the sample point in question and the target device's estimated location.
摘要:
A method for retrieving and representing media items in a communication network having a plurality of media items. In the embodiment, first at least one media item is retrieved from the communication network. Then, said retrieved media item is normalized. After normalizing, said retrieved media item is classified over a set of concepts, where each concept is associated with at least one description. Later, this classified media item may be compared with a description of information need.
摘要:
A method for estimating a receiver's location in a wireless communication environment having several channels. Each channel has at least one signal parameter that varies with location differently from the other channels. A set of calibration data is determined for each calibration point, each set including the location and at least one measured signal parameter for each of several channels. The calibration data serve as a basis for a statistical model of the signal parameters versus a receiver's location. A set of observed signal parameters is determined, the set including at least one signal parameter for each of several channels at the receiver's location. A location estimate approximating the location of the receiver is determined on the basis of the statistical model and the set of observed signal parameters.
摘要:
A method for determining an error estimate concerning a target device's location. The target device moves and communicates in a wireless environment using signals having at least one measurable signal value. A probabilistic model of the wireless environment indicates a probability distribution for signal values at several sample points in the wireless environment. A set of observations of signal values is made and the target device's location is estimated based on the probabilistic model and the set of observations. The error estimate (43) is determined as a combination of products over several sample points (SP). Each product comprises a probability distribution (41) for the sample point in question being the target device's location and a distance function (43) between the sample point in question and the target device's estimated location.