Abstract: An optical element and associated methods for generating an optical element and apparatus comprising the optical element, wherein the optical element comprises a first surface (10), a second surface (15), and a side wall structure (25) between the first and second surfaces. The side wall structure has an internally reflecting profile such that optical radiation incident on the first surface at an angle less than or equal to an acceptance angle and then incident on the side wall structure is internally reflected to the second surface by the side wall structure. In a first cross section of the optical element, the side wall structure has a first internally reflecting profile and/or the first surface has a first cross sectional profile.

Abstract: A method for encoding data for transmitting over a telecommunications network comprising: embedding at least one control or pilot data block within a plurality of real data blocks in the frequency domain; transforming real data in the real data blocks with control or pilot data in the control or pilot data blocks; and modulating the real data blocks and control or pilot data block with one or more transmission sub-carrier signals.

Abstract: An optical element and associated methods for generating an optical element and apparatus comprising the optical element, wherein the optical element comprises a first surface (10), a second surface (15), and a side wall structure (25) between the first and second surfaces. The side wall structure has an internally reflecting profile such that optical radiation incident on the first surface at an angle less than or equal to an acceptance angle and then incident on the side wall structure is internally reflected to the second surface by the side wall structure. In a first cross section of the optical element, the side wall structure has a first internally reflecting profile and/or the first surface has a first cross sectional profile.

Abstract: A sensor for condition monitoring the high voltage insulation of an electrical, generation, transmission or distribution system and/or an item of plant is described. The sensor comprises an impedance measurement unit that connects directly, via a single point of connection, to the electrical system to be tested. The electrical components of the impedance measurement unit are arranged so that high frequency partial discharge signals and low frequency power cycle information signal are preferentially transmitted through separate branches. Analysis of these separated signals thus enables extraction of information about the insulation of the electrical system being monitored. Safe operation of the sensor for users is also achieved through an opto-electronic circuit being employed to control the impedance measuring unit.

Abstract: A system and method for encoding data for transmission over a telecommunications network. The system and method involve embedding a control data block (Ik0) within a plurality of real data blocks (IN0). Preferably, real data in the real data blocks (INO) is convoluted with at least some of the control data in the control data block (Ik0) For example, each entry in each real data block (INO) may be phase convoluted with phase angle of the corresponding entry in the control block using an encoding module. Once this is done, the real data in the real data blocks and additionally the control data block in the control block is modulated with every sub carrier.

Abstract: An improved watertight gate for use in a port or canal is described. The watertight gate generally comprising two gate leaves and associated with each gate leaf is a foldable support structure and a gate position controller. The gate position controller interacts with the foldable support structure so as to move the associated gate leaf between an open and a closed position. By employing the gate position controller and the foldable support structure to control the gates the efficiency of the watertight seal provided by the gate is independent of water pressure produced by the surrounding bodies of water. Adjustable mounts attach the foldable support structures. These adjustable mounts provide for adjustment of the alignment of the watertight gate so minimizing the problems of installation alignment and reduced efficiency through wear and tear.

Abstract: A flexible water gate is described that is suitable for retaining water in a port, canal or river estuary. The gate is both economical to build and maintain and comprises a gate controller that allows a flexible member to be controllably moved between a closed and open position, as required. A flexible flood control barrier that comprises one or more of the aforementioned flexible water gates is also described. These gates are deployed side to side and provide an economical way of providing flood protection to an area susceptible to flood tides. When not in use the flexible membranes of the flexible water gates can be stored on the riverbed so permitting unrestricted access for marine vessels.

Abstract: Systems, apparatus and associated methods for use in the assessment of visual field functions. In particular, perimetry testing and visual evoked potential (VEP) testing is performed by a visual display device adapted to display visual stimulus patterns and a means for generating visual stimulus patterns within a predetermined visual field and for controlling the display of said visual stimulus patterns by said visual display device, wherein the means for generating visual stimulus patterns is adapted to generate a test stimulus for display in a central region of the visual field and to generate an inducing stimulus for display in a peripheral region of the visual field, and to control the visual display device so as to selectively display the test stimulus alone and in combination with the inducing stimulus in accordance with a predetermined test protocol.