Abstract: In response to determining that continuous data protection is to be enabled for a particular table of a database service, a service component verifies that automated transmission of change records of the table to a log-structured journal has been configured. A given change record comprises a before-image and an after-image associated with a committed database write, and is assigned a unique sequence number. In response to a determination to restore the table as of a specified point in time, a restore record set is identified from the journal with respect to a selected snapshot of the table. The restore record set includes change records which are not represented in the snapshot and are to be represented in the restored table. A restore result table is created using the selected snapshot and the restore record set.

Abstract: The techniques disclosed herein enable systems to reduce the time required to terminate a set of microservices for an application while ensuring high availability and preventing request failures. This is accomplished through a termination manager which retrieves request queues for the microservices to analyze outstanding requests that require processing prior to termination. Based on the outstanding requests, the termination manager constructs call graphs for each request. The call graphs capture the operational flow of the associated request by defining a sequence of microservices whose functionality is invoked by the request. From an initial analysis, the termination manager can determine that some of the microservices do not appear in the call graphs, indicating that the microservices are not needed to process the outstanding requests. Accordingly, the unneeded microservices are terminated.

Abstract: The techniques disclosed herein enable systems to reduce the time required to terminate a set of microservices for an application while ensuring high availability and preventing request failures. This is accomplished through a termination manager which retrieves request queues for the microservices to analyze outstanding requests that require processing prior to termination. Based on the outstanding requests, the termination manager constructs call graphs for each request. The call graphs capture the operational flow of the associated request by defining a sequence of microservices whose functionality is invoked by the request. From an initial analysis, the termination manager can determine that some of the microservices do not appear in the call graphs, indicating that the microservices are not needed to process the outstanding requests. Accordingly, the unneeded microservices are terminated.

Abstract: Techniques relating to vehicle maintenance are disclosed. These techniques include selecting a first data element and generating a plurality of clusters of data elements relating to maintenance of a vehicle, based on clustering data elements in one or more layers in a data hierarchy that depend a the first layer, and identifying one or more jobs relating to maintenance of the vehicle in each of the plurality of clusters, based on: (i) a start date for the respective job or (ii) an end date for the respective job. The techniques further include generating a path for each of the plurality of clusters based on the identified one or more jobs, each respective path comprising a plurality of jobs, approximating a critical path relating to maintenance of the vehicle based on the generated paths for each of the plurality of clusters, and maintaining the vehicle using the approximated critical path.

Abstract: The techniques disclosed herein enable systems to reduce the time required to terminate a set of microservices for an application while ensuring high availability and preventing request failures. This is accomplished through a termination manager which retrieves request queues for the microservices to analyze outstanding requests that require processing prior to termination. Based on the outstanding requests, the termination manager constructs call graphs for each request. The call graphs capture the operational flow of the associated request by defining a sequence of microservices whose functionality is invoked by the request. From an initial analysis, the termination manager can determine that some of the microservices do not appear in the call graphs, indicating that the microservices are not needed to process the outstanding requests. Accordingly, the unneeded microservices are terminated.

Abstract: A system for dynamic rating of a power grid may include a plurality of terminal units, and a controller. The terminal units may detect a voltage phasor and a current phasor at nodes of the power grid. The controller may, based on the voltage phasors and the current phasors of the plurality of nodes, determine a dynamic thermal stability power rating for each line, a dynamic angular stability power rating for each node, and a dynamic voltage stability power rating for each node. The controller may, based on the dynamic thermal stability power rating, the dynamic angular stability power rating, and the dynamic voltage stability power rating, determine a dynamic system rating for the power grid. The controller may control the power grid in response to the dynamic system rating.

Abstract: The techniques disclosed herein enable systems to reduce the time required to terminate a set of microservices for an application while ensuring high availability and preventing request failures. This is accomplished through a termination manager which retrieves request queues for the microservices to analyze outstanding requests that require processing prior to termination. Based on the outstanding requests, the termination manager constructs call graphs for each request. The call graphs capture the operational flow of the associated request by defining a sequence of microservices whose functionality is invoked by the request. From an initial analysis, the termination manager can determine that some of the microservices do not appear in the call graphs, indicating that the microservices are not needed to process the outstanding requests. Accordingly, the unneeded microservices are terminated.

Abstract: Information describing changes to a collection of items maintained by a database may be stored in a log file. The information in the log file may be converted into a stream of records describing the changes. The records may be directed to a computing node selected for performing a trigger function in response to the change, based on applying a hash function to a portion of the record, identifying a hash space associated with a value output by the hash function, and mapping from the hash space to the selected computing node.

Abstract: Methods for distributed histogram computation in a framework utilizing data stream sketches and samples are performed by systems and devices. Distributions of large data sets are scanned once and processed by a computing pool, without sorting, to generate local sketches and value samples of each distribution. The local sketches and samples are utilized to construct local histograms on which cardinality estimates are obtained for query plan generation of distributed queries against distributions. Local statistics of distributions are also merged and consolidated to construct a global histogram representative of the entire data set. The global histogram is utilized to determine a cardinality estimation for query plan generation of incoming queries against the entire data set. The addition of new data to a data set or distribution involves a scan of the new data from which new statistics are generated and then merged with existing statistics for a new global histogram.

Abstract: Information describing changes to a collection of items maintained by a database may be stored in a log file. The information in the log file may be converted into a stream of records describing the changes. The records may be directed to a computing node selected for performing a trigger function in response to the change, based on applying a hash function to a portion of the record, identifying a hash space associated with a value output by the hash function, and mapping from the hash space to the selected computing node.

Abstract: Information describing changes to a collection of items maintained by a database may be stored in a log file. The information in the log file may be converted into a stream of records describing the changes. The records may be directed to a computing node selected for performing a trigger function in response to the change, based on applying a hash function to a portion of the record, identifying a hash space associated with a value output by the hash function, and mapping from the hash space to the selected computing node.

Abstract: In the field of power system stability there is provided a method of predicting the presence of an out-of-step condition in a power system that includes a plurality of generators, the method including the steps of: (a) obtaining a differential value ({tilde over (?)}COIk) between a rotor angle (?k) of an individual one of the plurality of generators and an equivalent rotor angle (?COIk) of the centre of inertia of the remainder of the plurality of generators; (b) processing the differential value ({tilde over (?)}COIk) to determine whether the differential value ({tilde over (?)}COIk) is predicted to reach a predefined reference threshold (?threshold); and (c) predicting the presence of the out-of-step condition in the power system if the differential value ({tilde over (?)}COIk) is predicted to reach the predefined reference threshold (?threshold).

Abstract: Methods for distributed histogram computation in a framework utilizing data stream sketches and samples are performed by systems and devices. Distributions of large data sets are scanned once and processed by a computing pool, without sorting, to generate local sketches and value samples of each distribution. The local sketches and samples are utilized to construct local histograms on which cardinality estimates are obtained for query plan generation of distributed queries against distributions. Local statistics of distributions are also merged and consolidated to construct a global histogram representative of the entire data set. The global histogram is utilized to determine a cardinality estimation for query plan generation of incoming queries against the entire data set. The addition of new data to a data set or distribution involves a scan of the new data from which new statistics are generated and then merged with existing statistics for a new global histogram.

Abstract: The technology described herein is generally directed to a method of locating a fault in a multi-terminal electrical power transmission scheme, such as implemented in a power transmission scheme where each of six terminals is connected with one of four junctions via a power transmission section and each junction interconnects a plurality of power transmission sections. Aspects of the described technology can be directed to measuring the voltage and current at each terminal, calculating from the measured voltage and current at each terminal corresponding voltage and current phasors, determining from the calculated voltage and current phasors a synchronization difference between the measured voltage and current at a designated terminal and the measured voltage and current at each other terminal, modifying the calculated voltage and current phasors to compensate for each synchronization difference, and determining from the compensated voltage and current phasors the location of the fault.

Abstract: A flex seal assembly includes a plurality of duct segments configured to be disposed about a joint between a turbine of a turbine system and a diffuser of the turbine system. The plurality of duct segments includes a groove configured to extend circumferentially around the joint. Additionally, the plurality of duct segments includes a first duct segment of the plurality of duct segments and a second duct segment of the plurality of duct segments. The second duct segment includes a drain. Furthermore, the plurality of duct segments include insulation disposed within the groove of the plurality of duct segments.

Abstract: A trip apparatus for a circuit interruption device that comprises a coil operatively connectable to a circuit interruption device. The coil is configured to selectively operate the circuit interruption device to interrupt when a current flowing through the circuit interruption device exceeds a threshold. The trip apparatus also includes a current measuring device configured to selectively measure a coil current flowing through the coil to determine a measured coil current signal. In addition, the trip apparatus includes a monitoring device configured to determine the derivative of the measured coil current signal and to perform a correlation of the derivative of the measured coil current signal and a reference derivative of a reference coil current signal to determine a correlation output. The monitoring device is further configured to compare the correlation output with a reference correlation threshold to determine whether an operating condition of the coil is normal or abnormal.

Abstract: Systems and methods of determining a communication time delay in electrical power systems are provided. In one embodiment, a method of determining a communication time delay in a communication network between a local terminal and each of a plurality of remote terminals in a multi-terminal multi-junction electrical power system includes: (a) calculating a respective initial communication time delay between each remote terminal and the local terminal; (b) calculating a respective junction time delay between respective first, second and third pairs of adjacent junctions; and (c) correcting the calculated initial communication time delay of each remote terminal spaced from the local terminal by two or more junctions according to each corresponding junction time delay arising between the or each remote terminal and the local terminal.

Abstract: In response to determining that a secondary index is to be created for a particular table of a non-relational database service, a service component verifies that automated transmission of change records of the table to a log-structured journal has been configured. A given change record comprises a before-image and an after-image associated with a committed database write, and is assigned a unique sequence number. A change record propagator for the secondary index examines change records stored in the journal, and transmits selected change records to an index storage node. The index storage node builds the secondary index using the selected change records.

Abstract: There is provided a method of locating a fault in a power transmission scheme. The power transmission scheme includes power transmission sections and a first end connection point, a second end connection point, and at least one intermediate connection point. The method includes (i) measuring first and second end voltage phasors at the first and second end connection points respectively; (ii) obtaining a first set of voltage phasors, which includes the measured first end voltage phasor and includes respective voltage phasors at each of the second and intermediate connection points; (iii) obtaining a second set of voltage phasors, which includes the measured second end voltage phasor and includes respective voltage phasors at each of the first and intermediate connection points; (iv) comparing the first and second sets of voltage phasors to identify the power transmission section or connection point corresponding to the location of the fault.

Abstract: Information describing changes to a collection of items maintained by a database may be stored in a log file. The information in the log file may be converted into a stream of records describing the changes. The records may be directed to a computing node selected for performing a trigger function in response to the change, based on applying a hash function to a portion of the record, identifying a hash space associated with a value output by the hash function, and mapping from the hash space to the selected computing node.