Abstract: A system for accessing information stored in a distributed information database provides a community of intelligent software agents. Each agent can be built as an extension of a known viewer for a distributed information system such as the Internet WorldWide Web. The agent is effectively integrated with the viewer and can extract pages by means of the viewer for storage in an intelligent page store. The text from the information system is abstracted and is stored with additional information, optionally selected by the user. The agent-based access system uses keyword sets to locate information of interest to a user, together with user profiles such that pages being stored by one user can be notified to another whose profile indicates potential interest. The keyword sets can be extended by use of a thesaurus.

Abstract: A messaging system for passing messages between calling programs and called programs wherein all messages are passed within a defined message block and via a message interface. The message interface has memory for storing, for each called program, an identifier and a program interface. In use, the message interface receives a message block from a calling program containing an identifier, associates the identifier with a particular called program and a particular program interface, and sends a message block to the particular called program utilizing the particular program interface.

Abstract: A control interface for a data terminal includes a three-dimensional display of an environment which includes a number of objects. Different objects correspond to different data sources. The apparent location of the viewpoint in the environment is changed in response to input from the user. In response to the selection of a destination object by the user, the viewpoint moves from a current location to the location of the destination object gradually via a series of intermediate locations. The speed with which the viewpoint moves is progressively reduced as the destination object is approached. The speed may also be further reduced if the direction of gaze of the viewpoint is moved by the user away from the destination object during the flight. As an alternative to direct selection of the destination object, the user may select a vehicle object to take the viewpoint to a predetermined location.

Abstract: Calculate the log frame energy value of each of a pre-determined number n of frames of an input speech signal and apply a matrix transform to the n log frame energy values to form a temporal matrix representing the input speech signal. The matrix transform may be a discrete cosine transform.

Abstract: A community of collaborative software agents work together in a domain to provide functionality such as providing of communications services or control of a chemical process. A system is provided for building such communities of collaborative software agents. Each software agent has data concerning its relationship(s) with other agents of the community. A visualizer is provided for debugging the community which offers several partial views of the communications between and within agents, organized according to the relationships between agents. By using multiple partial views, such as messages between selected agents and job status reports within single agents, the visualizer is capable of particularly effective debugging.

Abstract: The invention concerns an integrated computer and telephony system and a method of integrated computer telephony in which at least one main is switch is capable of receiving incoming telephone calls and of dialling outgoing calls. A computer terminal is associated with the switch and means are provided for recognising that a telephone number connected to the switch as an incoming call is associated with said computer terminal; together with and means for causing said computer terminal to give an indication that an incoming call has been received, with the call being held by the switch so that the computer terminal indication is without the telephone being caused to ring.

Abstract: A method of voice message transmission is performed within a telecommunication network. It may include: recording, via a telephone line from a first terminal, a voice message to a designated second terminal; attempting to connect to the second terminal via a telephone line; where the step of attempting to connect is successful, regenerating the recorded message to the second terminal; and under predetermined conditions, attempting to set up a return call to the first terminal.

Abstract: A planar optical waveguide has a liquid filled wave guiding region, which may be straight, coiled or otherwise folded, with filling channels provided transversely along its length. The wave guiding region may be fabricated in a substrate with a reservoir on the substrate to facilitate filling through the filling channels.

Abstract: A terminal computer is used to send instructions to a host computer through a public network to open and close application programs and to transmit data between the application programs and the terminal computer through the public network. In order to open application programs, the terminal computer establishes an initial connection between the two computers and instructions are sent over this initial connection to open application programs. The host computer establishes an additional connection for each application program. In the terminal computer, a respective terminal emulator window is created for each additional connection. For each application program, data is transmitted over the respective additional connection using a character-based protocol. In the terminal computer, the data is converted from the character-based format to a bit-mapped graphical format and then displayed in the respective terminal emulator window.

Abstract: A method of automatically creating a database on the basis of a set of category headings uses a set of keywords provided for each category heading. The keywords are used by a processing platform to define searches to be carried out on a plurality of search engines connected to the processing platform via the Internet. The search results are processed by the processing platform to identify the URLs embedded in the search results. The URLs are then used to retrieve the pages to which they refer from remote data sources in the Internet. The processing platform then filters and scores the pages to determine which pages are the most relevant to the original categories. Internet location information for the most relevant pages is stored in the database.

Abstract: A computer booking system is provided for booking individual ones of a set resources to users of the resources. The resources may be, for example, channels between multiplexes in a telecommunications network. The database creates a pair of data nodes for each booking. Each node has a user field for specifying the user for whom the booking is scheduled, an event field for specifying whether the event associated with the node is the beginning or end of a booking, and a time field for specifying the time at which the event is scheduled to occur. Each node is also located in a single linked list (the time list) of nodes in which the nodes are arranged in order of their event times. Each node is also located in a respective of a set of lists (the value lists). The value lists are arranged in order of rank and each new node is located in the value list of the lowest possible rank.

Abstract: A communication network includes a number of network nodes linked together by transmission paths. A network manager controls acceptance of calls onto transmission paths by classifying an incoming call and selecting from the database an appropriate mean to peak bit rate distribution. This selected distribution is then used with the monitored transmission path load to determine a posterior distribution which reflects the load. The decision to accept or reject the call is made on the basis of the posterior distribution by a call acceptance algorithm considering the effective bandwidth for example.

Abstract: An echo detecting system includes data stores for storing signals from up and down channels respectively. The signals undergo pre-processing to identify signals forms characteristic of speech and instruct a measurement unit to carry out comparison using cross-correlation techniques between the signals stored in the stores only when such characteristics are detected. This reduces the processing power required and raises the accuracy of the correlations. Parallel processing techniques allow echoes with longer delay periods to be detected. The results of the measurement may be used to generate an echo-cancellation signal.

Abstract: An optical diffraction grating is formed from a region of photonic crystalline material Light is coupled into the photonic crystalline material, and the grazingly emergent output beam is collected. The photonic crystalline material may include an array of holes formed in a substrate of dielectric material, e.g., InP, and integrated with planar waveguide structures.

Abstract: A recognition system includes a speech recognition processing unit for processing input speech signals to indicate similarity to predetermined patterns to be recognized. The recognition processing unit is arranged to repeatedly partition the input speech signal into a pattern-containing portion and, preceding and following the pattern-containing portions, noise or silence portions, and to identify a pattern corresponding to the pattern containing portion. An output supplies a recognition signal indicating recognition of one of the patterns. A pause detector detects the noise or silence portion which follows the pattern-containing portion. In response to its detection, a signal identifying the pattern currently corresponding to the pattern portion is supplied to the output. Also provided are similarly operating rejection portions.

Abstract: In a telecommunications network of the kind which handles non-time-critical calls (NTCC) in addition to normal telephony, a congestion indication is transmitted to NTCC transmitting platforms if volume and/or rate limit for a particular communications route or switch is exceeded. Transmitting platforms (9,10,11) establish a transmission rate based on a gapping ration (GR). On receipt of a congestion signal the platforms calculate and Inter call delay based on a random number multiplied by a weighting factor determined from the current value of GR. This provides a period during which calls are not attempted after which GR is adjusted using a common ratio to provide a higher value of GR thus transmission rate (or the rate at which calls are offered) to the congestion route is less onerous. Consecutive call failures result in a rapid increase in the value of GR leading to longer ICDs (to allow the congested route/switch to recover) and a lower traffic loading on recovery.

Abstract: An optical filter and method of filtering uses a multi-mode waveguide having a first number n modes and a second waveguide having a different number m modes are coupled in series, where n and m are integers and n>m, and where the interaction of different modes at the interface of the two waveguides filters an optical signal propagating through the waveguides to provide a desired response characteristic. A lateral offset between the central axes of the waveguides at their interface is changed to control the response of the filter. For a multiple wavelength optical source uses, a filter coupled in the optical cavity including a laser gain medium provides interaction of different modes at the interface of waveguides in the filter to filter an optical signal propagating in the cavity thereby providing an output signal with multiple peaks at different wavelengths with a predetermined spacing.

Abstract: The pitch of synthesized speech signals is varied by separating the speech signals into a spectral component and an excitation component. The latter is multiplied by a series of overlapping window functions synchronous, in the case of voiced speech, with pitch timing mark information corresponding at least approximately to instants of vocal excitation, to separate it into windowed speech segments which are added together again after the application of a controllable time-shift. The spectral and excitation components are then recombined. The multiplication employs at least two windows per pitch period, each having a duration of less than one pitch period. Alternatively each window has a duration of less than twice the pitch period between timing marks and is asymmetric about the timing mark.

Abstract: An optical beam having a high radio-frequency modulation is generated by generating a lower frequency modulation, using it to control the optical output of a laser and further modulating the optical output in an optical modulator by a control signal having another lower frequency modulation generated. Either or both of the lower frequency modulations also carries an information containing modulation. the effect of the optical modulator is to up-convert the modulation carried by the optical beam by the modulation frequency of the control signal. The optical modulator may be a Mach-Zehnder interferometer. The non-linearity of such a modulator with respect to its control input may be exploited by selecting the amplitude of the control signal such that the optical output is up-converted by an integer multiple of the initial modulation frequency. These methods avoid the need to apply the high frequency modulation to either the laser input or the control input directly.

Abstract: An optical fibre for use in fibre lasers has the lasing additive eg Er.sup.3+, concentrated in center of the core. Preferably the core has an inner region which contains the additive and an outer region which is dopant free. The concentration of the dopant reduces the pump threshold for a laser and improves the gain performance for a given pump power. The fibre is conveniently made in MCVD. The use of Al.sub.2 O.sub.3 in the inner zone appears to reduce loss of dopant during tube collapse.