2,347 research outputs found

    Space station automation of common module power management and distribution, volume 2

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    The new Space Station Module Power Management and Distribution System (SSM/PMAD) testbed automation system is described. The subjects discussed include testbed 120 volt dc star bus configuration and operation, SSM/PMAD automation system architecture, fault recovery and management expert system (FRAMES) rules english representation, the SSM/PMAD user interface, and the SSM/PMAD future direction. Several appendices are presented and include the following: SSM/PMAD interface user manual version 1.0, SSM/PMAD lowest level processor (LLP) reference, SSM/PMAD technical reference version 1.0, SSM/PMAD LLP visual control logic representation's (VCLR's), SSM/PMAD LLP/FRAMES interface control document (ICD) , and SSM/PMAD LLP switchgear interface controller (SIC) ICD

    Design and Development of a Run-Time Monitor for Multi-Core Architectures in Cloud Computing

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    Cloud computing is a new information technology trend that moves computing and data away from desktops and portable PCs into large data centers. The basic principle of cloud computing is to deliver applications as services over the Internet as well as infrastructure. A cloud is a type of parallel and distributed system consisting of a collection of inter-connected and virtualized computers that are dynamically provisioned and presented as one or more unified computing resources. The large-scale distributed applications on a cloud require adaptive service-based software, which has the capability of monitoring system status changes, analyzing the monitored information, and adapting its service configuration while considering tradeoffs among multiple QoS features simultaneously. In this paper, we design and develop a Run-Time Monitor (RTM) which is a system software to monitor the application behavior at run-time, analyze the collected information, and optimize cloud computing resources for multi-core architectures. RTM monitors application software through library instrumentation as well as underlying hardware through a performance counter optimizing its computing configuration based on the analyzed data

    High Availability and Scalability Schemes for Software- Defined Networks (SDN)

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    Title from PDF of title page, viewed on September 8, 2015Dissertation advisor: Baek-Young ChoiVitaIncludes bibliographic references (pages 127-136)Thesis (Ph.D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2015A proliferation of network-enabled devices and network-intensive applications require the underlying networks not only to be agile despite of complex and heterogeneous environments, but also to be highly available and scalable in order to guarantee service integrity and continuity. The Software-Defined Network (SDN) has recently emerged to address the problem of the ossified Internet protocol architecture and to enable agile and flexible network evolvement. SDN, however, heavily relies on control messages between a controller and the forwarding devices for the network operation. Thus, it becomes even more critical to guarantee network high availability (HA) and scalability between a controller and its forwarding devices in the SDN architecture. In this dissertation, we address HA and scalability issues that are inherent in the current OpenFlow specification and SDN architecture; and solve the problems using practical techniques. With extensive experiments using real systems, we have identified that iii the significant issues of HA and scalability in operations of a SDN such as single point of failure of multiple logical connections, multiple redundant configuration, unrecoverable interconnection failure, interface flapping, new flow attack, and event storm. We have designed and implemented the management frameworks that deal with SDN HA and scalability issues that we have observed from a real system. The proposed frameworks include various SDN HA and scalability strategies. For SDN HA, we have developed several SDN control path HA algorithms such as ensuring logical control path redundancy, transparency of a controller cluster, and fast and accurate failure detection. We validate the functionalities of the proposed SDN HA schemes with real network experiments. The proposed SDN control path HA algorithms overcome the limitations of the current Open- Flow specification and enhance performance as well as simplify management of SDN control path HA. For SDN scalability, we have proposed and developed our management framework in two different platforms; an embedded approach in the OpenFlow switch and an agent-based approach with the SUMA platform that is located near the Open- Flow switch. These platforms include various algorithms that enhance scalability of SDN such as Detect and Mitigate Abnormality (DMA), Modify and Annotate Control (MAC), and Message Prioritization and Classification (MPC). We have shown that the proposed framework effectively detects and filters malicious and abnormal network behaviors such as new flow attack, interface flapping, and event storm.Introduction -- Related work -- Measurement and Analysis of an Access Network’s Availability -- SDN Control Path High Availability -- SDN Scalable Network Management -- Summary and Future Wor

    Flight Avionics Hardware Roadmap

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    As part of NASA's Avionics Steering Committee's stated goal to advance the avionics discipline ahead of program and project needs, the committee initiated a multi-Center technology roadmapping activity to create a comprehensive avionics roadmap. The roadmap is intended to strategically guide avionics technology development to effectively meet future NASA missions needs. The scope of the roadmap aligns with the twelve avionics elements defined in the ASC charter, but is subdivided into the following five areas: Foundational Technology (including devices and components), Command and Data Handling, Spaceflight Instrumentation, Communication and Tracking, and Human Interfaces

    INVESTIGATING THE IMPACT OF TREE-BASED NETWORK TOPOLOGY ON THE SDN CONTROLLER PERFORMANCE

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    Software Defined Networking (SDN) is an important technology that enables a new approach to how we develop and manage networks. SDN divides the data plane and control plane and promotes logical centralization of network control so that the controller can schedule the data in the network effectively through the OpenFlow protocol. The performance and capabilities of the controller itself are important. The impact of network topology type on controller performance can be very significant. In order to have better communication in SDN, it is essential to have an analysis of the performance of specific network topologies. In this paper, we simulate ONOS and RYU controllers and compare their different network parameters under the proposed complex custom Tree-based topology. A network topology has been designed using a Mininet emulator, and the code for topology is executed in Python. From the throughput, packet transmission rate, and latency analysis, the ONOS controller displayed better results than RYU, showing that it can respond to requests more efficiently under complex SDN topologies and traffic loads. On the contrary, the RYU controller provides better results for the less complex SDN networks
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