Algorithms for data placement, reconfiguration and monitoring in storage networks

In this thesis we address three problems related to self-management of storage networks - data placement, data reconfiguration and data monitoring. Examples of such storage networks include centrally managed systems like Storage Area Networks and Network Attached Storage devices, or even highly distributed systems like a P2P network or a Sensor Network. One of the crucial functions of a storage system is that of deciding the placement of data within the system. This data placement is dependent on the demand pattern for the data and subject to constraints of the storage system. For instance, if a particular data item is very popular the storage system might want to host it on a disk with high bandwidth or make multiple copies of the item. We present new results for some of these data placement problems. As the demand pattern changes over time, the storage system will have to modify its placement accordingly. Such a modification in placement will typically involve movement of data items from one set of disks to another or changing the number of copies of a data item in the system. For such a modification to be effective, it should be computed and applied quickly since the system is running inefficiently during this reconfiguration. We propose new schemes to reconfigure the data placement to deal with changing demand. To re-compute data placement periodically and to reconfigure the data placement, we need to continuously track of the demand distribution in the storage system and also be able to answer aggregate queries about the demand distribution. The data monitoring portion of the thesis deals with such problems that arise in the context of distributed data management applications. A monitoring system for such a scenario would need to process large amounts of data from a widely distributed set of data sources. The thesis presents new schemes that improve communication-efficiency of existing methods that address these problems

Advanced transport operating system software upgrade: Flight management/flight controls software description

The Flight Management/Flight Controls (FM/FC) software for the Norden 2 (PDP-11/70M) computer installed on the NASA 737 aircraft is described. The software computes the navigation position estimates, guidance commands, those commands to be issued to the control surfaces to direct the aircraft in flight based on the modes selected on the Advanced Guidance Control System (AGSC) mode panel, and the flight path selected via the Navigation Control/Display Unit (NCDU)

Fault tolerant programmable digital attitude control electronics study

The attitude control electronics mechanization study to develop a fault tolerant autonomous concept for a three axis system is reported. Programmable digital electronics are compared to general purpose digital computers. The requirements, constraints, and tradeoffs are discussed. It is concluded that: (1) general fault tolerance can be achieved relatively economically, (2) recovery times of less than one second can be obtained, (3) the number of faulty behavior patterns must be limited, and (4) adjoined processes are the best indicators of faulty operation

GAME THEORETIC APPROACH TO RADIO RESOURCE MANAGEMENT ON THE REVERSE LINK FOR MULTI-RATE CDMA WIRELESS DATA NETWORKS

This work deals with efficient power and rate assignment to mobile stations (MSs) involved in bursty data transmission in cellular CDMA networks. Power control in the current CDMA standards is based on a fixed target signal quality called signal to interference ratio (SIR). The target SIR represents a predefined frame error rate (FER). This approach is inefficient for data-MSs because a fixed target SIR can limit the MS's throughput. Power control should thus provide dynamic target SIRs instead of a fixed target SIR. In the research literature, the power control problem has been modeled using game theory. A limitation of the current literature is that in order to implement the algorithms, each MS needs to know information such as path gains and transmission rates of all other MSs. Fast rate control schemes in the evolving cellular data systems such as cdma2000-1x-EV assign transmission rates to MSs using a probabilistic approach. The limitation here is that the radio resources can be either under or over-utilized. Further, all MSs are not assigned the same rates. In the schemes proposed in the literature, only few MSs, which have the best channel conditions, obtain all radio resources. In this dissertation, we address the power control issue by moving the computation of the Nash equilibrium from each MS to the base station (BS). We also propose equal radio resource allocation for all MSs under the constraint that only the maximum allowable radio resources are used in a cell. This dissertation addresses the problem of how to efficiently assign power and rate to MSs based on dynamic target SIRs for bursty transmissions. The proposed schemes in this work maximize the throughput of each data-MS while still providing equal allocation of radio resources to all MSs and achieving full radio resource utilization in each cell. The proposed schemes result in power and rate control algorithms that however require some assistance from the BS. The performance evaluation and comparisons with cdma2000-1x-Evolution Data Only (1x-EV-DO) show that the proposed schemes can provide better effective rates (rates after error) than the existing schemes

Proceedings of the Space Shuttle Integrated Electronics Conference, volume 3

Proceedings of space shuttle integrated electronics conference with emphasis on data systems design - Vol.

An Exploration of Maximum Power Point Tracking Algorithms

This project investigated the performance of various solar maximum power point tracking algorithms on a single hardware platform. It also developed a low-cost hardware platform including a rudimentary solar cell emulator circuit and a maximum power point tracker circuit to test these algorithms. Additionally, the project covered the development of the two software algorithms that were tested in the project: the ”Sweep” algorithm and the ”Perturb and Observe” algorithm

3rd Many-core Applications Research Community (MARC) Symposium. (KIT Scientific Reports ; 7598)

This manuscript includes recent scientific work regarding the Intel Single Chip Cloud computer and describes approaches for novel approaches for programming and run-time organization

Advances in Reinforcement Learning

Reinforcement Learning (RL) is a very dynamic area in terms of theory and application. This book brings together many different aspects of the current research on several fields associated to RL which has been growing rapidly, producing a wide variety of learning algorithms for different applications. Based on 24 Chapters, it covers a very broad variety of topics in RL and their application in autonomous systems. A set of chapters in this book provide a general overview of RL while other chapters focus mostly on the applications of RL paradigms: Game Theory, Multi-Agent Theory, Robotic, Networking Technologies, Vehicular Navigation, Medicine and Industrial Logistic

Reliability Mechanisms for Controllers in Real-Time Cyber-Physical Systems

Cyber-physical systems (CPSs) are real-world processes that are controlled by computer algorithms. We consider CPSs where a centralized, software-based controller maintains the process in a desired state by exchanging measurements and setpoints with process agents (PAs). As CPSs control processes with low-inertia, e.g., electric grids and autonomous cars, the controller needs to satisfy stringent real-time constraints. However, the controllers are susceptible to delay and crash faults, and the communication network might drop, delay or reorder messages. This degrades the quality of control of the physical process, failure of which can result in damage to life or property. Existing reliability solutions are either not well-suited for real-time CPSs or impose serious restrictions on the controllers. In this thesis, we design, implement and evaluate reliability mechanisms for real-time CPS controllers that require minimal modifications to the controller itself. We begin by abstracting the execution of a CPS using events in the CPS, and the two inherent relations among those events, namely network and computation relations. We use these relations to introduce the intentionality relation that uses these events to capture the state of the physical process. Based on the intentionality relation, we define three correctness properties namely, state safety, optimal selection and consistency, that together provide linearizability (one-copy equivalence) for CPS controllers. We propose intentionality clocks and Quarts, and prove that they provide linearizability. To provide consistency, Quarts ensures agreement among controller replicas, which is typically achieved using consensus. Consensus can add an unbounded-latency overhead. Quarts leverages the properties specific to CPSs to perform agreement using pre-computed priorities among sets of received measurements, resulting in a bounded-latency overhead with high availability. Using simulation, we show that availability of Quarts, with two replicas, is more than an order of magnitude higher than consensus. We also propose Axo, a fault-tolerance protocol that uses active replication to detect and recover faulty replicas, and provide timeliness that requires delayed setpoints be masked from the PAs. We study the effect of delay faults and the impact of fault-tolerance with Axo, by deploying Axo in two real-world CPSs. Then, we realize that the proposed reliability mechanisms also apply to unconventional CPSs such as software defined networking (SDN), where the controlled process is the routing fabric of the network. We show that, in SDN, violating consistency can cause implementation of incorrect routing policies. Thus, we use Quarts and intentionality clocks, to design and implement QCL, a coordination layer for SDN controllers that guarantees control-plane consistency. QCL also drastically reduces the response time of SDN controllers when compared to consensus-based techniques. In the last part of the thesis, we address the problem of reliable communication between the software agents, in a wide-area network that can drop, delay or reorder messages. For this, we propose iPRP, an IP-friendly parallel redundancy protocol for 0 ms repair of packet losses. iPRP requires fail-independent paths for high-reliability. So, we study the fail-independence of Wi-Fi links using real-life measurements, as a first step towards using Wi-Fi for real-time communication in CPSs