2,347 research outputs found
Space station automation of common module power management and distribution, volume 2
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
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
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An Emergent Architecture for Scaling Decentralized Communication Systems (DCS)
With recent technological advancements now accelerating the mobile and wireless Internet solution space, a ubiquitous computing Internet is well within the research and industrial community's design reach - a decentralized system design, which is not solely driven by static physical models and sound engineering principals, but more dynamically, perhaps sub-optimally at initial deployment and socially-influenced in its evolution. To complement today's Internet system, this thesis proposes a Decentralized Communication System (DCS) architecture with the following characteristics: flat physical topologies with numerous compute oriented and communication intensive nodes in the network with many of these nodes operating in multiple functional roles; self-organizing virtual structures formed through alternative mobility scenarios and capable of serving ad hoc networking formations; emergent operations and control with limited dependency on centralized control and management administration. Today, decentralized systems are not commercially scalable or viable for broad adoption in the same way we have to come to rely on the Internet or telephony systems. The premise in this thesis is that DCS can reach high levels of resilience, usefulness, scale that the industry has come to experience with traditional centralized systems by exploiting the following properties: (i.) network density and topological diversity; (ii.) self-organization and emergent attributes; (iii.) cooperative and dynamic infrastructure; and (iv.) node role diversity. This thesis delivers key contributions towards advancing the current state of the art in decentralized systems. First, we present the vision and a conceptual framework for DCS. Second, the thesis demonstrates that such a framework and concept architecture is feasible by prototyping a DCS platform that exhibits the above properties or minimally, demonstrates that these properties are feasible through prototyped network services. Third, this work expands on an alternative approach to network clustering using hierarchical virtual clusters (HVC) to facilitate self-organizing network structures. With increasing network complexity, decentralized systems can generally lead to unreliable and irregular service quality, especially given unpredictable node mobility and traffic dynamics. The HVC framework is an architectural strategy to address organizational disorder associated with traditional decentralized systems. The proposed HVC architecture along with the associated promotional methodology organizes distributed control and management services by leveraging alternative organizational models (e.g., peer-to-peer (P2P), centralized or tiered) in hierarchical and virtual fashion. Through simulation and analytical modeling, we demonstrate HVC efficiencies in DCS structural scalability and resilience by comparing static and dynamic HVC node configurations against traditional physical configurations based on P2P, centralized or tiered structures. Next, an emergent management architecture for DCS exploiting HVC for self-organization, introduces emergence as an operational approach to scaling DCS services for state management and policy control. In this thesis, emergence scales in hierarchical fashion using virtual clustering to create multiple tiers of local and global separation for aggregation, distribution and network control. Emergence is an architectural objective, which HVC introduces into the proposed self-management design for scaling and stability purposes. Since HVC expands the clustering model hierarchically and virtually, a clusterhead (CH) node, positioned as a proxy for a specific cluster or grouped DCS nodes, can also operate in a micro-capacity as a peer member of an organized cluster in a higher tier. As the HVC promotional process continues through the hierarchy, each tier of the hierarchy exhibits emergent behavior. With HVC as the self-organizing structural framework, a multi-tiered, emergent architecture enables the decentralized management strategy to improve scaling objectives that traditionally challenge decentralized systems. The HVC organizational concept and the emergence properties align with and the view of the human brain's neocortex layering structure of sensory storage, prediction and intelligence. It is the position in this thesis, that for DCS to scale and maintain broad stability, network control and management must strive towards an emergent or natural approach. While today's models for network control and management have proven to lack scalability and responsiveness based on pure centralized models, it is unlikely that singular organizational models can withstand the operational complexities associated with DCS. In this work, we integrate emergence and learning-based methods in a cooperative computing manner towards realizing DCS self-management. However, unlike many existing work in these areas which break down with increased network complexity and dynamics, the proposed HVC framework is utilized to offset these issues through effective separation, aggregation and asynchronous processing of both distributed state and policy. Using modeling techniques, we demonstrate that such architecture is feasible and can improve the operational robustness of DCS. The modeling emphasis focuses on demonstrating the operational advantages of an HVC-based organizational strategy for emergent management services (i.e., reachability, availability or performance). By integrating the two approaches, the DCS architecture forms a scalable system to address the challenges associated with traditional decentralized systems. The hypothesis is that the emergent management system architecture will improve the operational scaling properties of DCS-based applications and services. Additionally, we demonstrate structural flexibility of HVC as an underlying service infrastructure to build and deploy DCS applications and layered services. The modeling results demonstrate that an HVC-based emergent management and control system operationally outperforms traditional structural organizational models. In summary, this thesis brings together the above contributions towards delivering a scalable, decentralized system for Internet mobile computing and communications
High Availability and Scalability Schemes for Software- Defined Networks (SDN)
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
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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
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
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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