Abstract: This invention relates to methods and devices for time and frequency synchronization, especially over packet networks using, for example, the IEEE 1588 Precision Time Protocol (PTP). Timing protocol messages are exposed to artifacts in the network such as packet delay variations (PDV) or packet losses. Embodiments of the invention provide a digital phase locked loop (DPLL) based on direct digital synthesis to provide both time and frequency signals for use at the slave (time client). An example of this DPLL in conjunction with a recursive least squares mechanism for clock offset and skew estimation is also provided.

Abstract: This invention relates to methods and devices for time and frequency synchronization, especially over packet networks using, for example, the IEEE 1588 Precision Time Protocol (PTP). Timing protocol messages are exposed to artifacts in the network such as packet delay variations (PDV) or packet losses. Embodiments of the invention provide a recursive least squares mechanism for clock offset and skew estimation. A major potential advantage of such estimation is that it does not require knowledge of the statistics of the measurement noise and process noise. An implementation using a digital phase locked loop based on direct digital synthesis to provide both time and frequency signals for use at the slave (time client) is also provided.

Abstract: This invention relates to methods and devices for frequency distribution based on, for example, the IEEE 1588 Precision Time Protocol (PTP). Packet delay variation (PDV) is a direct contributor to the noise in the recovered clock and various techniques have been proposed to mitigate its effects. Embodiments of the invention provide a mechanism to directly measure and remove PDV effects in the clock recovery mechanism at a slave clock. One particular embodiment provides a clock recovery mechanism including a phase-locked loop (PLL) with a PDV compensation feature built-in. An aim of the invention is to enable a slave clock to recover the master clock to a higher quality as if the communication path between master and slave is free of PDV. This technique may allow a packet network to provide clock synchronization services to the same level as time division multiplexing (TDM) networks and Global Positioning System (GPS).

Abstract: This invention relates to methods and devices for clock offset and skew estimation. The invention has particular application in the alignment of slave clocks to a master clock. In embodiments of the invention, the slave clock employs an independent free running clock and a recursive estimation technique to estimate the clock offset and clock skew between the slave and master clocks. The slave can then use the offset and skew to correct the free running clock to reflect an accurate image of the master clock.

Abstract: This invention relates to methods and devices for entropy-based location fingerprinting, in particular for use over wireless local-area networks (WLANs). The invention has particular application in localization for indoor environments. In embodiments of the invention, an entropy-based fingerprint is determined at a number of predetermined locations within the desired area of localization during an off-line phase and subsequently used in an on-line mode to determine the location of a receiver. In particular embodiments, the fingerprint is a vector of entropy estimates of the channel transfer function (CTF) between a mobile terminal and all access points within coverage. The invention seeks to provide a fingerprinting localization solution that has a simplicity of structure, leading to advantages in storage and pattern recognition requirements, and robustness by proving a unique measure of information that is related to the channel experienced at the location of the mobile terminal.

Abstract: This invention relates to methods and devices for clock synchronization. The invention makes particular use of IEEE 1588 with offset and skew correction. In embodiments of the invention, the IEEE 1588 Precision Time Protocol is used to exchange time stamps between a time server and a client from which the client can estimate the clock offset and skew. In embodiments of the invention a free running clock at the client is provided with an estimation technique based on the time stamps from the IEEE 1588 PTP message exchange between the server and client clocks. The offset and skew from the estimation process can be combined with the local free running clock to give a synchronized local clock which is an accurate image of the master clock.

Abstract: A method and system of scheduling demands on a system having a plurality of resources are provided. The method includes the steps of, on receipt of a new demand for resources: determining the total resources required to complete said demand and a deadline for the completion of that demand; determining a plurality of alternative resource allocations which will allow completion of the demand before the deadline; for each of said alternative resource allocations, determining whether, based on allocations of resources to existing demands, said alternative resource allocation will result in a utilization of resources which is closer to an optimum utilization of said resources; and selecting, based on said determination, one of said alternative resource allocations to complete said demand so as to optimise utilization of resources of the system.

Abstract: This invention relates to methods and devices for motor speed control. The invention has particular application in the control of motors over packet networks. In embodiments of the invention, phase-locked loop principles are used to remotely control the speed of an electric motor over a packet network. The setpoint for the motor is supplied by arriving timestamps from a speed-mapped variable frequency source. The shaft speed of the motor is measured with a tachometer with its output proportional to the motor speed. Any deviation of the actual speed from the setpoint is amplified by the power amplifier whose output drives the motor. Speed control over packet networks allow smoother operation of a process, acceleration control, different operating speeds for each process recipe, compensation for changing process variables, slow operation for setup purposes, adjustments to the rate of production, accurate positioning, and control torque or tension of a system.

Abstract: This invention relates to methods and devices for clock offset and skew estimation. The invention has particular application in the alignment of slave clocks to a master clock. In embodiments of the invention, the slave clock employs an independent free running clock and a recursive estimation technique to estimate the clock offset and clock skew between the slave and master clocks. The slave can then use the offset and skew to correct the free running clock to reflect an accurate image of the master clock.

Abstract: This invention relates to methods and devices for clock synchronization. The invention makes particular use of IEEE 1588 with offset and skew correction. In embodiments of the invention, the IEEE 1588 Precision Time Protocol is used to exchange time stamps between a time server and a client from which the client can estimate the clock offset and skew. In embodiments of the invention a free running clock at the client is provided with an estimation technique based on the time stamps from the IEEE 1588 PTP message exchange between the server and client clocks. The offset and skew from the estimation process can be combined with the local free running clock to give a synchronized local clock which is an accurate image of the master clock.

Abstract: This invention relates to methods and devices for channel identification. The invention is particularly concerned with techniques for non-line of sight channel identification. In embodiments of the invention the methods and devices are used for channel identification in wireless geolocation systems. Embodiments of the invention make use of an entropy estimation of the channel to distinguish channel conditions and in particular to identify line-of-sight and non-line-of-sight channels and which can be used to solve the NLOS problem of determining relative distances between transmitter and receiver. In particular embodiments an entropy estimation of the channel impulse response (CIR) is used to construct a robust entropy-based channel identification technique. As a result, more accurate localization in indoor and other multipath environments may be possible.

Abstract: The invention relates to a method and system that provide a continuous querying mechanism that analyses real-time data streams to generate relevant results. It leverages data grid and event processing technology to provide a high performance and extremely scalable continuous querying solution. An embodiment of the invention provides a flexible querying language and data storage to allow users to register their interest in specific types of data, e.g. processes. The users are notified of matching results using an event-based mechanism. In order to efficiently analyse a large amount of data, the embodiment uses a grid infrastructure that allows storage of the data across many grid nodes and distributes the query execution workload, avoiding the bottleneck represented by constantly querying a database. Continuous queries are stored in a Continuous Query Registry and that Registry is invoked every time an insert or update event occurs on the triple store.

Abstract: The invention relates to a method and system that provide a high performance and extremely scalable triple store within the Resource Description Framework (or alternative data models), with optimized query execution. An embodiment of the invention provides a data storage and analysis system to support scalable monitoring and analysis of business processes along multiple configurable perspectives and levels of granularity. This embodiment analyses data from processes that have been already executed and from ongoing processes, as a continuous flow of information. This embodiment provides defining and monitoring processes based on no initial domain knowledge about the process and such that the process will be built only from the incoming flow of information. Another embodiment of the invention provides a grid infrastructure that allows storage of data across many grid nodes and distribution of the workload, avoiding the bottleneck represented by constantly querying a database.

Abstract: This invention relates to methods and devices for entropy-based location fingerprinting, in particular for use over wireless local-area networks (WLANs). The invention has particular application in localization for indoor environments. In embodiments of the invention, an entropy-based fingerprint is determined at a number of predetermined locations within the desired area of localization during an off-line phase and subsequently used in an on-line mode to determine the location of a receiver. In particular embodiments, the fingerprint is a vector of entropy estimates of the channel transfer function (CTF) between a mobile terminal and all access points within coverage. The invention seeks to provide a fingerprinting localization solution that has a simplicity of structure, leading to advantages in storage and pattern recognition requirements, and robustness by proving a unique measure of information that is related to the channel experienced at the location of the mobile terminal.

Abstract: This invention relates to assignment of mobile clients (such as mobile telephones or software agents) to mainly stationary servers (such as mobile network base stations or computer servers) with the objective of reducing or minimizing the number of active servers. Once the number of users of a server drops below a specified level, the server may be deactivated resulting in power and efficiency savings. Preferably the method of the invention operates dynamically and during run time. In certain embodiments, the method can accept trade-offs in the quality of service or the number of active servers. In an embodiment of the invention, servers are arranged to “compete” with adjacent servers for their clients. This competition may be in a self-amplifying manner such that with the effect that more “popular” servers are more likely to succeed thus resulting in servers which are below a utilization threshold and can therefore be switched off.

Abstract: The present invention provides a method of synchronising the frequency of a slave clock to that of a master, preferably using a packet network.

Abstract: A system is provided for monitoring the performance of a service within a business process environment is provided, the system including, locally to said service and preferably for each service: an information collector collecting information about the performance of said service in real-time; a database storing information about the performance of said service over time; and a control unit processing the information collected by said information collector and determining information to be stored in said database. A method of distributed monitoring of the performance of services within a business process environment is also provided.

Abstract: A method and system of scheduling demands on a system having a plurality of resources are provided. The method includes the steps of, on receipt of a new demand for resources: determining the total resources required to complete said demand and a deadline for the completion of that demand; determining a plurality of alternative resource allocations which will allow completion of the demand before the deadline; for each of said alternative resource allocations, determining whether, based on allocations of resources to existing demands, said alternative resource allocation will result in a utilization of resources which is closer to an optimum utilization of said resources; and selecting, based on said determination, one of said alternative resource allocations to complete said demand so as to optimise utilisation of resources of the system.