Abstract: A dental implant for anchoring in bone, wherein said bone comprises an outer cortical bone section and an inner cancellous bone section is made of a body of resorbable material such as coral, having a portion capable of being wedged into the cancellous bone. The body of coral has a generally cylindrical root portion, an emergent portion capable of being wedged into said outer cortical bone section, and a transgingival coronal portion being sized to extend beyond said emergent portion to end beyond a gingival layer, and an abutment portion and a head for retention of said prosthetic device at the other end, wherein said abutment portion meets said coronal portion at an interface beyond said gingival layer. The body of coral is substantially electroplated with a suitable plating material such as gold. At least some of the root portion is absent said plating material so as to allow the bone to enter the substantially plated body of coral to resorb and replace at least some of the coral.

Abstract: On-line measurements of an amount of dissolved solids in a liquid sample are determined by using both conductivity and UV measurements. More particularly, an amount of dissolved solids in a pulp and paper mill process water or effluent is determined by irradiating at least a portion of a liquid sample with ultraviolet light and subsequently measuring an absorption of the light by the liquid sample. Furthermore the conductivity of the liquid sample is measured and subsequently a computation is from a first relationship between the measured absorption of the first wavelength by the liquid sample and the measured conductivity of the liquid sample using a suitably programmed processor.

Abstract: Faces are one of the most commonly recognized features among people. According to the invention a system for recognizing intensity images of faces is provided. Intensity images of a face are captured and normalized. The intensity images are transformed, filtered and then transformed again. The filter is based on a three-dimensional image of a face against which the intensity image is being compared. The result is a form of correlation that is substantially illumination independent.

Abstract: A straw splitter for longitudinally splitting pieces of cereal straw into separated strands for use in making a panel, board or beam is provided. A cutting shear roller and a gripping shear roller are rotatable around their longitudinal axis at different circumferential speeds. The pieces of straw are split due to shear between the cutting shear roller and the gripping shear roller. The shear rollers each comprise parallel grooves with cutting edges oriented at a predetermined angle to the roller axis such that the grooves of the gripping shear roller cross the grooves of the cutting shear roller providing a scissoring action for splitting the straw into long strands.

Abstract: A method and circuit is disclosed wherein two beams exiting opposite ends of a resonant optical cavity, such as a Fabry-Perot (FP) etalon for example, are provided via waveguides or via free space directed by mirrors to a combining region where the beams can interfere with one another to provide a desired output response. In one embodiment, multiplexed channels of light can be demultiplexed by the device described heretofore, or alternatively, the phase relationship between these two beams can be altered prior to their being combined to provide, for example, a linearized output response useful in applications such as wavelength locking. By varying the reflectivity of the optical cavity reflectors and/or by varying the phase relationship between the two beams exiting the optical cavity, a variety of desired output responses can be realized.

Abstract: A reference system for an optical wavelength scanner, used for measuring wavelengths of radiation from an optical device. The system utilizes a wavelength reference comprising a fixed fiber Fabry-Perot (FFP) filter in combination with a reference fiber Bragg grating (FBG) having an accurately known reflection wavelength to minimize the effects of drift and non-linearities in the scanner and to allow a simple flexure element to be used to position a dispersive grating. The wavelengths of the reference comb of the fixed FFP are determined by reference to that of the reference FBG. Then, the peaks or notches in the light intensity from the device under test are located with respect to the comb of peaks produced by the reference. In a most simple embodiment two ports are coupled so as to provide their output light to the dispersive element simultaneously and only a single collimating lens is required for collimating light from the output ports.

Abstract: A multi-stage optical isolating device having at least three stages includes birefringent crystals for separating shifting and combining an incoming beam of light into orthogonal polarized beams. The multi-stage device also includes at least three Faraday rotators that rotate incoming light propagating through the device in a same direction. The inclusion of a reciprocal rotator in the form of a half-wave plate advantageously obviates orienting the Faraday rotators differently.

Abstract: A record-playback attack on a security system involves recording authorisation information such as passwords and playing them back to the server at a later time to unlawfully access a system. A method is disclosed for detecting record-playback of biometric information. When biometric information is provided to a server, it is always slightly different due to the nature of human input, health, etc. When two biometric input samples are substantially identical, a record-playback attack on system security is suspected and access is denied.

Abstract: A method of enhancing network security is provided for a communication session initiated between a first computer and a second other computer. From the first computer to the second computer in communications therewith a process for securing communications therebetween is transmitted. One such process is a biometric characterisation process for characterising fingerprints. The process is for execution on the second computer and is selected to be compatible therewith. Communications from the second computer to the first computer are secured using the transmitted process on the second computer and using, on the first computer, a compatible process to the transmitted process. The host computer can modify or replace the process or data particular to the process before each session, during a session, or at intervals.

Abstract: In the past, user authorization based on biometric information was conducted by correlating a single instance of biometric information against a template. By using this method, a percentage of the population is difficult to authenticate. Further, due to skin damage and injuries, sometimes biometric information is not suited to identification. A sore throat affecting voice information and scraped finger tips affecting fingerprint information are two examples of common problems with authorization in dependence upon biometric information. A method of authenticating a user in dependence upon biometric input information is disclosed. The method allows a user to select biometric information sources and a number of repetitions for each source in order to customize the process of biometric user authentication.

Abstract: The present invention relates to a coupling element for coupling between optical elements, for instance a ferrule encased fiber end and a lens, two lenses, or filter and lens assemblies, which provides a reliable joint with a determined spacing and angular orientation between them if needed. Advantageously, the coupling in accordance with the present invention does not obscure optical transmission through the coupling with an epoxy layer. A stand off element is provided which has opposite reference surfaces for joining the end faces of the optical elements and a central aperture, slot or equivalent open area for light transmission. In use the open area is aligned, for example with the fiber end and the desired port in the lens. Adhesive connection can be provided between the opposite surfaces of the stand off element and the coupling end faces of the optical elements. No epoxy is applied over the open area. Other securing methods such as external securing elements can be used.

Abstract: In the design of transcutaneous energy transfer devices, variation in spacing between coils results in energy transfer efficiency changes. These changes may have significant effect on a system. It is proposed to provide a plurality of implanted coils for receiving energy simultaneously. Preferably, a plurality of coil pairs is used for transferring energy simultaneously. Also, a feedback system for use in a multiple coil system is disclosed.

Abstract: A multi-pass optical filter using two identical filters provides narrower band filtering by double filtering an optical signal passing therethrough. Although passing a beam of light at an optical filter having a substantially thick optical thickness is known to have significant coupling losses due to angular misalignment of the output beam and the receiving optical fibre, it has been found that twice filtering in the conventional manner by serially coupling two same filters increases coupling losses. However, this invention provides a coupling arrangement wherein losses are significantly lessened by offsetting the axes of the lensed filters such that the beam exiting the first filter couples into the second filter as it would be reflected backward into the first filter.

Abstract: An optical filter is provided having first and second graded index (GRIN) lenses preferably disposed in a coaxial relationship so that they have a common optical axis. Each of the GRIN lenses has an end face providing a port at predetermined location. The ports are disposed on opposite sides of the optical axis and each of the ports is substantially equidistant from the optical axis, so as to be oppositely offset from the optical axis by a same amount. The filter also includes an optical interference filter disposed between other end faces of the first and second graded index lenses. By providing at least four spaced ports, equidistant from the optical axis, such that two ports form a first couplet on opposite sides of the axis from each other and such that two other ports form a second couplet on opposite sides of the axis from each other, wherein one of the ports of one couplet is optically coupled with one of the ports from the other couplet, an add and drop circuit may be realized.

Abstract: A polarization beam splitter combiner uses a birefringent crystal that is a fraction of the size of conventional crystals used in similar devices. Since the crystal is considerably shorter in length, the beam passing through the crystal can be uncollimated, spreading very little from one end to the other. Launching uncollimated beams through a short small crystal obviates the requirement for lenses at the end face of the crystal having two waveguides coupled thereto. Since lenses are not required the waveguides at the input/output end face can be very closely spaced apart. Conventional lensed devices utilizing a pair of lenses at an input/output end face must be considerably larger in order to accommodate the lenses and resulting collimated beams.

Abstract: A method is disclosed for improving portability of secure encryption key data files. The method provides for re-securing key data files according to different security processes for mobility. For porting an encryption key secured using a fingerprint authentication process to a system having only a password authentication process, a user selects password authentication process, provides a fingerprint and is authorised, provides a new password and then the encryption key is accessed according to the fingerprint authentication process and secured according to the password authentication process. This allows the use of specialised security hardware at one location while retaining an ability to transport encryption keys in a secure fashion to other locations, which do not have similar security hardware.

Abstract: The state of polarization of an input light beam is tested by determining four components of a Stokes vector of the light. These correspond to components of the light in three polarization states, S.sub.1 : linear horizontal, S.sub.2 : linear at 45 degrees, S.sub.3 : right circularly polarized, and S.sub.0 the total power. It is not necessary to filter out these components directly and measure their powers. In accordance with this invention it is more convenient to measure the powers in three arbitrary polarization states that have known relationships to each other, and, also measure the total power. The actual Stokes vector components is calculated from this information. Conveniently, a device having three polarization beam splitting surfaces and a prism provides a novel way in which to obtain the necessary information from an input beam so that a set of equations can be solved to determine the state of polarization the input beam.

Abstract: A system of interconnected functionally identical modules for switching P optical signals to P locations in a non-blocking manner is disclosed. Each of the functionally identical modules provides a same function, which may or may not be provided in an identical manner. Each module has several of first ports and several second ports optically coupled to second ports of other modules. Switching means are provided for switching means for switching between the first ports and the second ports. Each module has at least a second port is directly coupled to another second port. Providing a system wherein modules are identical provides numerous advantages. The architecture further provides the advantage of ease of repair within no disturbance to communications being handled by other modules.

Abstract: A useful device is provided for coupling or splitting optical signals from one port to another. The symmetry of a lens is utilized in a manner whereby two linear arrays of optical ports are disposed adjacent the optical axis of the lens equidistant from the optical axis of the lens. An at least partially reflecting optical element is disposed at a collimating end of the lens. Signals launched into one array of ports reflects back to the second array of ports at the same end. In another embodiment of the invention utilizing these two linear arrays of waveguides, two matched lenses having an element disposed between are used as a coupler/splitter. In this arrangement ports are positioned on opposite sides of the optical axis equidistant from it.