Abstract: A multi-phase power converter with current matching is provided. The apparatus may include a control circuit to control a first phase of a power converter having a plurality of phases, and a phase matching circuit. The phase matching circuit may remove a DC component from an output ripple voltage of the converter, detect when respective ones of the plurality of phases begins generating its respective phase current and output a phase detector signal, extract a signal proportional to the first phase current and a signal proportional to either the remaining or total phase currents, output first and second voltages respectively proportional to the average of the first phase current and the remaining or total phase current, and output a corrective signal based on the difference between the first and second voltage. The control circuit may control the first phase based on the corrective signal.

Abstract: Embodiments of the present invention provide a system for detecting vibrations from a component. The system operates by coupling vibrations from a component to a membrane using a flexible connecting line. The membrane converts the vibrations into acoustic waves that are transmitted through a medium. Finally, a microphone detects the acoustic waves in the medium and converts the acoustic waves into electrical signals.

Abstract: A system that detects vibrations from a mechanical component, such as a disk drive. The system includes an excitation rod, a membrane, and a microphone. During operation, the mechanical component is coupled to the excitation rod which is coupled to the membrane, so that vibrations from the mechanical component are mechanically coupled through the excitation rod to the membrane. The membrane then converts the mechanical vibrations into acoustic waves that are transmitted through a medium. The microphone detects the acoustic waves in the medium and converts the acoustic waves into signals.

Abstract: A method and an apparatus for determining cooling fan speeds that should be avoided to prevent vibational resonance with system enclosures, given ambient conditions, and/or current geographic altitude. An exemplary method to determine one or more ranges of fan speed for one or more cooling fans in a chassis with one or more systems to avoid vibrational resonance in the chassis caused by the one or more cooling fans is provided. The method includes determining a range of operable fan speed for the one or more cooling fans that meets the cooling goal of the one or more systems in the chassis, wherein the one or more cooling fans are used to cool the chassis, and the one or more systems. The method also includes scanning fan speed for the one or more cooling fans over the determined range of operable fan speed, and collecting and analyzing read or write rates on a hard disk drive in the one or more systems over the determined range of operable fan speed.

Abstract: Embodiments of the present invention provide a system for detecting vibrations from a component. The system operates by coupling vibrations from a component to a membrane using a flexible connecting line. The membrane converts the vibrations into acoustic waves that are transmitted through a medium. Finally, a microphone detects the acoustic waves in the medium and converts the acoustic waves into electrical signals.

Abstract: Disclosed is a method for stateless group communication based on constructing and encoding sender based trees. The headers obtained by encoding the distribution trees are inserted in each communication packet. The encoding allows partial or full decoding of the distribution trees. The encoding is performed to minimize the overhead of the header and the processing required for partial decoding of the distribution tree. The invention includes mechanisms for processing the encoded header at intermediate nodes in the distribution tree in order to determine the next communication nodes and mechanisms for modification and re-encoding of the trees in order to provide resilience to network failures or to react to application level specified conditions.

Abstract: A system that detects vibrations from a mechanical component, such as a disk drive. The system includes an excitation rod, a membrane, and a microphone. During operation, the mechanical component is coupled to the excitation rod which is coupled to the membrane, so that vibrations from the mechanical component are mechanically coupled through the excitation rod to the membrane. The membrane then converts the mechanical vibrations into acoustic waves that are transmitted through a medium. The microphone detects the acoustic waves in the medium and converts the acoustic waves into signals.

Abstract: Methods and arrangements for constructing a network overlay via embedding an interconnection network in a network overlay graph. Presented herein is one example of an approximation algorithm for efficient mapping of hypercube topology on a network overlay of N nodes such that the average network delay distance measured on the network overlay is minimized. The network delay distances between pairs of overlay nodes are measured on the shortest network paths. The mapping of the interconnection topology to the network overlay nodes preferably involves assigning 2m m-length binary indexes to the network overlay nodes. There is proposed herein a polynomial time algorithm for interconnection topology embedding using iterative cluster division and node binary index assignment. There is further proposed herein a method for construction of network overlays through interconnection network topology embedding, with the objective of optimizing a quality of service metric (e.g.

Abstract: We present exemplary methods involving hierarchical indexing of an application space, and exemplary techniques for scalable management of shared application state update distribution. The application space is partially replicated at each individual client who controls a limited number of static and dynamic objects of the application space. State updates are generated for each modification of objects' dynamic attributes. Multiple dynamic objects may change state simultaneously, requiring dissemination of the state updates to non-overlapping groups of clients. A client's communication interest is described using multiple dynamic attributes. The communication interest space is represented as an N-dimensional attribute space with coordinates spanning the set of dynamic object attributes contained in the communication interest space. We provide a method for partitioning the application space, creation of communication interest cells and hierarchical indexing of the communication interest space.

Abstract: A new search algorithm for optimal topology construction which utilizes a sequence of transpositions of the topology adjacency matrix index. Preferably, the search involves: evaluating an objective function for each transposition of the current index permutation state; selecting the transposition corresponding to the gradient of the objective function at convex regions of the permutation space; and allowing the transposition search to follow a positive gradient within an window length equal to the maximum distances between local edge objective minima.

Abstract: A method and apparatus for managing communications for collaborative applications. Middleware uses, network, application, and middleware resource information together with user information to facilitate communications between the application resources and the users via a hierarchical control structure that implements a communication overlay tree. That overlay tree is implemented in view of network constraints, and on the users and on their communication constraints. The middleware provides user index identifiers that inform the application that specific users have communication interests in specific parts of the application space. To send data to users that are interested in a specific part of the application space the application sends that data with a list of user index identifiers. The middleware then associates the user index identifiers with individual users and routes sent data to the individual users along the overlay tree.

Abstract: A method of clustering communication nodes based on network attributes such as network delays and forwarding capacity; on communication interest attributes; and on application attributes such as quality of service preferences/constraints (e.g. end-to-end delay constraints, bandwidth constraints) in providing communications between users and application servers. A multi-attribute communication feature vector is formed. That vector is comprised of network attributes (such as available bandwidth, client location attributes in the IP map), communication interests attributes (client request for content updates, client subscription to specific data items or to a set of proximal data sources in network space or application/virtual space) and quality of service requirements (such as delay and loss constraints is used to from efficient group communication mechanisms for distributed collaborative applications. Then the multi-attribute communication feature vectors are clustered.

Abstract: A method, computer readable media, and apparatus of hierarchical-based communication session and data distribution management that indexes client's communication preferences and network attribute information. Indexing is used to generate dynamic group membership lists that map into communication groups. Indexing is replicated at control nodes in the network overlay to allow distributed management of group membership. Send/receive operations are decoupled through data distribution and the indexing structure. Senders and receivers register their group communication interests to a parent node in the hierarchy. The session control structure aggregates client interest and dynamically updates replicas at control nodes which are selected according to the changes in registered client interest. The indexing structure has self-managing properties for automatic clustering based on client session and data interests, and dynamic partitioning of the session/data interest attribute space.

Abstract: Disclosed is a method for stateless group communication based on constructing and encoding sender based trees. The headers obtained by encoding the distribution trees are inserted in each communication packet. The encoding allows partial or full decoding of the distribution trees. The encoding is performed to minimize the overhead of the header and the processing required for partial decoding of the distribution tree. The invention includes mechanisms for processing the encoded header at intermediate nodes in the distribution tree in order to determine the next communication nodes and mechanisms for modification and re-encoding of the trees in order to provide resilience to network failures or to react to application level specified conditions.