Abstract: The present invention includes modular fence, gate, railing, and security bar systems that can be easily prefabricated of a minimal number of parts, assembled at the installation site without the need for specialized skills or tools, and having a semi-customizable ornamental appearance that can be changed subsequent to the initial installation. A method of connecting the components by aligning holes formed in the rails with similar holes formed in pickets, balusters, and tabs; inserting a connecting bolt through the holes; and fastening nuts to the bolts is claimed. To add strength to the systems' connections, the pickets and/or balusters are formed to have flattened parts with a hole centered therein; the flattened part formed to fit between two rails. Another unique feature is the detachable head on the nut used to secure the connections. Once the head is detached, the connecting bolt and nut remaining have the appearance of a rivet.

Abstract: Data elements stored in a distributed data structure are accessible by means of a hierarchical routing network in which routes through the network to individual data elements are flagged. The network includes communicating links between nodes extending from a "root node" to a plurality of end nodes. The end nodes contain the data elements. To find a data element, a search message entering the network at an end node passes through the network towards the root node until it encounters a flagged route to the relevant data element. Thereafter it passes along the route to the end node containing the relevant data element. The invention is relevant to personal numbering services in a communications network. In this case, the data elements each comprise hardware addresses for users of the network. If a user moves in relation to the network, their hardware address will change and, in many cases, the relevant end node will also change.

Abstract: An optical communications network includes a plurality of passive optical networks (PONs) connected in a ring in PON address order, in which communication channels between terminals are wavelength multiplexed. Each optical link between adjacent PONs includes a tunable wavelength filter, and a common wavelength allocation database is arranged dynamically to select wavelengths for a connection and to provide corresponding control signals to the appropriate filters such that the allocated wavelengths for a connection can pass over only the transmission path between the terminals. Thus the same wavelengths can be re-used for another connection whose transmission path does not overlap with any existing transmission path involving those wavelengths.