Abstract: A hierarchical control system for a tandem axle assembly for a vehicle is provided. The hierarchical control system includes a vehicle level controller, an actuator, a shift controller, and a sensor. The shift controller is capable of placing the tandem axle assembly in at least a first operating condition and a second operating condition using the actuator. In response to the sensor and an operating condition of at least one of the power source and the transmission of the vehicle, the shift controller adjusts a manner of placing the tandem axle assembly in at least one of the first operating condition and the second operating condition. The hierarchical control system facilitates performing a shifting procedure in an automatic manner or as desired by an operator of the vehicle without excessively increasing a cost and a complexity of the tandem axle assembly.

Abstract: A method and system for analyzing a corpus of data artifacts is disclosed. The method comprises obtaining, by a computer, a semantic representation of the data artifacts, where the semantic representation indicates (1) entities identified in the data artifacts, and (2) semantic relationships among the entities as indicated by the data artifacts. The method further comprises clustering the data artifacts into clusters of semantically related data artifacts based on the semantic representation and inferring additional semantic relationships between pairs of the entities. The inferring comprises applying, on a cluster-by-cluster basis, a multi-tiered network of inference engines to a portion of the semantic representation corresponding to the cluster, where the multi-tiered network of inference engines includes a domain-independent inference tier and a domain-specific inference tier.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: A method and system for harmonizing and mediating ontologies to search across large data sources is disclosed. The method comprises receiving a query targeting a first ontology. The method further comprises translating the query into one or more translated queries, each translated query targeting a respective ontology different from the first ontology. For each of the queries, issuing the query to a respective database organized according to the respective ontology of the query, and receiving a respective result set for the query, wherein the respective result set corresponds to the respective ontology of the query. The method further comprises translating the respective result set into a translated result set corresponding to the first ontology, aggregating the result sets into an aggregated result set corresponding to the first ontology, and returning the aggregated results set corresponding to the first ontology.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: A hierarchical control system for a tandem axle assembly for a vehicle is provided. The hierarchical control system includes a vehicle level controller, an actuator, a shift controller, and a sensor. The shift controller is capable of placing the tandem axle assembly in at least a first operating condition and a second operating condition using the actuator. In response to the sensor and an operating condition of at least one of the power source and the transmission of the vehicle, the shift controller adjusts a manner of placing the tandem axle assembly in at least one of the first operating condition and the second operating condition. The hierarchical control system facilitates performing a shifting procedure in an automatic manner or as desired by an operator of the vehicle without excessively increasing a cost and a complexity of the tandem axle assembly.

Abstract: One embodiment of the present invention provides a system for facilitating an upgrade of a cluster of servers in the presence of one or more inaccessible nodes in the cluster. During operation, the system receives an instruction to upgrade an older version of a distributed software program installed on each of a plurality of nodes forming the cluster. The system installs and activates a newer version of software on a subset of the plurality of nodes, the subset having fewer nodes than the entire cluster. The system receives an instruction to forcibly upgrade the cluster. Subsequently, the system upgrades the cluster so that the subset of nodes operate with the newer version of software, in which each node remains a member of the cluster during the upgrade.

Abstract: A method and system for analyzing a corpus of data artifacts is disclosed. The method comprises obtaining, by a computer, a semantic representation of the data artifacts, where the semantic representation indicates (1) entities identified in the data artifacts, and (2) semantic relationships among the entities as indicated by the data artifacts. The method further comprises clustering the data artifacts into clusters of semantically related data artifacts based on the semantic representation and inferring additional semantic relationships between pairs of the entities. The inferring comprises applying, on a cluster-by-cluster basis, a multi-tiered network of inference engines to a portion of the semantic representation corresponding to the cluster, where the multi-tiered network of inference engines includes a domain-independent inference tier and a domain-specific inference tier.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: Disclosed is a method, mechanism, and computer usable medium for managing and accessing static and shard data. In one approach, described is a method and mechanism for implementing group dependent keys (GDKs) in a computing system, in which the GDK is visible to all members of a distributed system, but its value(s) and subtree(s) could be different for different groups. Members of each group see the same view of the value and subtree of a GDK. Also disclosed is a method, mechanism, and computer usable medium for implementing group dependent links (GDLs) in a computing system. According to one approach, a data transformation function is used to coordinate changes to different versions of shared data.

Abstract: Techniques are described herein for synchronizing cluster time. According to one technique, a master node is appointed in a cluster. Other “slave” nodes periodically synchronize their clocks with the master node. To synchronize its clock with the master node, a slave node sends a timestamped message to the master node, which also timestamps the message and sends the message back to the slave node, which then timestamps the message again. Based on the timestamps, the slave node is able to determine the difference between the master node's clock's time and slave node's clock's time, compensating for the message travel time between master node and slave node. Depending on various circumstances, and based on the determined difference, the slave node adjusts its clock so that the time indicated by the slave node's clock at least begins to approach more closely the time indicated by the master node's clock.

Abstract: A method and apparatus is provided for determining the most probable cause of a problem observed in a complex multi-host system. The approach relies on a probabilistic model to represent causes and effects in a complex computing system. However, complex systems include a multitude of independently operating components that can cause temporary anomalous states. To reduce the resources required to perform root cause analysis on each transient failure, as well as to raise the confidence in the most probable cause of a failure that is identified by the model, inputs to the probabilistic model are aggregated over a sliding window of values from the recent past.

Abstract: A method and mechanism for managing data to resolve incompatibilities between different versions of data is disclosed. According to one approach, incompatibilities to private data is managed using group/member dependent key(s)/link(s), static shared data is managed using group/member dependent key(s)/link(s), and dynamic shared data is managed using data transformation function(s).

Abstract: Techniques are described herein for synchronizing cluster time. According to one technique, a master node is appointed in a cluster. Other “slave” nodes periodically synchronize their clocks with the master node. To synchronize its clock with the master node, a slave node sends a timestamped message to the master node, which also timestamps the message and sends the message back to the slave node, which then timestamps the message again. Based on the timestamps, the slave node is able to determine the difference between the master node's clock's time and slave node's clock's time, compensating for the message travel time between master node and slave node. Depending on various circumstances, and based on the determined difference, the slave node adjusts its clock so that the time indicated by the slave node's clock at least begins to approach more closely the time indicated by the master node's clock.

Abstract: Techniques are provided for managing replicated data items in a cluster of shared nothing nodes. The techniques include synchronously propagating changes to one or more replicas, while asynchronously propagating changes to the remaining replicas. Because the replicas to which the change is synchronously replicated may be a relatively small percentage of the total number of replicas, the overhead associated with performing an update is reduced. The process of selecting which nodes are involved in the synchronous update operation may take into account a variety of factors, including which replicas are available at the time the update operation is being performed.

Abstract: Less-restrictive techniques are provided for ensuring that replicated-data systems will never provide out-of-date version of data items. A replicated-data system maintains a version number, a membership group identifier, and a membership count, with each replica of a data item. These values are maintained in such a way as to allow the replicated-data system to reliably satisfy some read requests even though half, or less than half, of the replicas of the data item are available.

Abstract: A system and techniques are described for managing key-value pairs using an architecture that does not restrict its users to any specific platform or storage subsystem. According to one aspect of the invention, the repository is portable in that the architecture need not change based on the environment and platform in which the repository is used. Rather, the portion of the architecture that is platform-specific is limited to plug-ins at a storage abstraction layer of the repository. The plug-ins expose the same storage abstraction interface to the other layers of the repository, but are implemented to interact with different platforms and storage subsystems. Consequently, in response to being ported from one platform to another, the repository may simply change the plug-in to invoke for persistent storage operations.

Abstract: A method is disclosed for computing clutch engagement characteristics of a friction clutch system in a vehicle powertrain. A dynamic model of the system is used under conditions that cause clutch slipping. Algebraic equations defining a functional relationship between clutch torque and an engagement angle have characteristic parameters that are estimated using a non-linear least squares technique. The non-linear least squares technique repetitively minimizes the difference between a measured clutch output speed and a clutch output speed from the system dynamic model for the same inputs until a small insignificant error is reached. Parameter estimates are used to update each engagement characteristic.

Abstract: A computer implemented CPU utilization prediction technique is provided. CPU utilization prediction is implemented described in continuous time as an auto-regressive process of the first order. The technique used the inherent autocorrelation between successive CPU measurements. A specific auto-regression equation for predicting CPU utilization is provided. CPU utilization prediction is used in a computer cluster environment. In an implementation, CPU utilization percentage values are used by a scheduler service to manage workload or the distribution of requests over a vast number of CPUs.

Abstract: A group of shared-storage resources are being maintained as replicas by the nodes of a cluster. Each node in the cluster maintains a set of pointers to the members of the group. As membership changes, the set of pointers should be changed accordingly. For various, reasons, the set of pointers of a node are not changed and may point to shared-storage resources that are no longer members of the group and/or not point to shared-storage resources that are members of the group. By recording a history of membership changes in the shared-storage resources, and comparing the recording to what a node thinks the shared resources should be, an incorrect set of pointers can be detected and corrective active undertaken.