摘要:
An externally controlled fan drive includes a fluid clutch that alters torque delivered to a fan housing to rotate the fan housing at a target fan speed. An adaptive controller measures the actual fan speed and adaptively updates the control logic to compensate for variable physical characteristics of the fan device.
摘要:
A reconfigurable variable blank-holder force system (and method) for producing sheet metal stampings comprises a portable hydraulic unit, controlled by a digital control system and a knowledge-based expert system to enable reconfigurability and an easy transition from the try-out stage to production. The knowledge-base has a hierarchical structure and includes stored information about part geometry, material properties and press parameters. The expert system enables an operator to determine optimal blank-holder forces, and to fine-tune through a graphical interface unit. The optimal blank-holder forces are generated by hydraulic force actuators, using a controller running a nonlinear algorithm that accounts for valve nonlinearities, variable flow-rate and numbers of operational cylinders. The portable hydraulic unit preferably comprises hydraulic cylinders with quick disconnect hoses, a manifold, servo-valves and a pump unit. A structured method to utilize this system to produce sheet metal stampings is also described. An article embodying the method is included.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
Systems and methods for supporting and maintaining a distributed global map of transaction identifiers at the gateway processes using a hashing algorithm configured on each application process to access the global maps. A global map of transaction identifiers that associates global transaction identifiers with remote local transaction identifiers is maintained at each gateway process. When an application process performing work for a particular transaction desires to export the transaction to a remote node, a hashing function configured on the application process is applied to the global transaction identifier associated with the particular transaction. Application of the hashing function to the global transaction identifier identifies one of the gateway processes. The global transaction identifier is stored to the global map associated with that gateway process. When the remote transaction manager associated with the remote node responds with a local transaction identifier for a local transaction initiated at the remote node, the local transaction identifier is stored to the identified gateway's global map in association with the global transaction identifier. Each application process is configured with the same hashing function so that the same gateway process will always be identified given a particular global transaction identifier. If the same or another application process desires to export to a remote node a transaction that has already been exported, the hashing function on that application process identifies the same gateway through which the transaction was originally exported.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.