U.S. Philips Corporation

Meinhard D Ullrich

Peter Beyerlein

Dietmar W Kunz

Bernhard J Ruber

Xavier Aubert

Jesus-Manuel Duque-Anton

For the recognition of spoken text it is necessary that the words to be recognized are available in acoustically modeled form, i.e. in the form of a sequence of reference values. These reference values are determined from a known, spoken text during a training phase, in that from this text there are derived characteristic values at regular intervals, as during the recognition, which characteristic values are arranged according to triphones so as to form groups or so-called clusters. These groups constitute the basis for the reference values. In the case of a recognition system involving a very large vocabulary, however, not all triphones will occur during the training phase, unless the text is prohibitively long. In order to enable the reference values to be determined also for words containing triphones which have not occurred, such a triphone must be associated with an available group. To this end, all groups are examined so as to determine whether they have the same central phoneme in interrelationship with either the left-hand or the right-hand phoneme as the triphone to be associated. The group for which this is most often the case is selected as the associated group. The vast majority of words can thus be modeled on the basis of triphones. Modifications of this rule are described for words containing triphones which cannot be directly associated in this manner.

Method of determining an acoustic model for a word

A spread-spectrum based cellular mobile radio system resolves average mutual interferences (I.sup.u (j).sub.av, I.sup.d (j).sub.av) between radio zones j, j') from a total interference experienced in a radio zone (j), using statistical methods. First, interference measurements are carried out in the radio zones (Z1, Z2), and data is transmitted to a central control arrangement (CA) which resolves the average mutual interferences. Then, these average mutual interference (I.sup.u (j).sub.av, I.sup.d (j).sub.av) are used in an optimization process for acquiring access control parameters (x) for controlling traffic per radio zone (Z1, Z2). In the optimizing process various objective functions may be applied so as to fulfil system operator demands. Thus, system overload is avoided, and further, a flexible tool is provided for satisfying operator demands.

Spread-spectrum based cellular mobile radio system, and a control

A system and method are used for recognising a time-sequential input pattern (20), which is derived from a continual physical quantity, such as speech. The system has input means (30), which accesses the physical quantity and therefrom generates a plurality of input observation vectors. The input observation vectors represent the input pattern. A reference pattern database (40) is used for storing a plurality of reference patterns. Each reference pattern includes a sequence of reference units, where each reference unit is represented by at least one associated reference vector .mu..sub.a in a set {.mu..sub.a } of reference vectors. A localizer (50) is used for locating among the reference patterns stored in the reference pattern database (40), a recognised reference pattern, which corresponds to the input pattern. The locating includes selecting a subset {.mu..sub.s } of reference vectors from said set {.mu..sub.a } for each input observation vector o by calculating a measure of dissimilarity between the input observation vector o and each reference vector of the set {.mu..sub.a }. A number of reference vectors .mu..sub.a, whose measures of dissimilarity with said input observation vector o are the smallest, are used as the subset {.mu..sub.s } of reference vectors. The reference vectors of the subset {.mu..sub.s } are used to calculate for each reference pattern, a pattern similarity score. The recognised pattern is one of the reference patterns for which an optimum of the pattern similarity scores is calculated. Output means (70) are used for outputting the recognised pattern.

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Koln, Germany

Meinhard D Ullrich