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4th International Workshop on Semantic Web Information Management, SWIM'12

作者： Angelou, Evangelos Papailiou, Nikolaos Konstantinou, Ioannis Tsoumakos, Dimitrios Koziris, Nectarios Computing Systems Laboratory School of Electrical and Computer Engineering National Technical University of Athens Greece

ISBN: (纸本)9781450314466

Modern cloud infrastructures based on virtual hardware provide new opportunities and challenges for developers and system administrators alike. Most notable is the promise of resource elasticity, whereby the infrastructure can increase or decrease in size based on demand. Utilizing elastic resources, applications can provide better quality of service and reduce cost by only paying for the required amount of resources. In this work, we extensively study the performance of some popular NoSQL databases over an elastic cloud infrastructure. NoSQL databases focus on analytical processing of large scale datasets, offering increased scalability over commodity hardware. We then proceed to describe TIRAMOLA, a cloud-enabled framework for automatic provisioning of elastic resources on any NoSQL platform. Our system administers cluster resources (VMs) according to user-or application-specified constraints through an expandable monitoring and command-issuing module. Users can easily modify resizing policies, based on application-specific metrics and thus fully utilize the elasticity of the underlying infrastructure. As a realistic use-case, we apply this framework on top of a fully distributed RDF store backed by an elastic NoSQL database. Letting TIRAMOLA manage the number of committed resources results in automated cluster resize actions and throughput maximization, while application experts need only provide simple elasticity rules. © 2012 ACM.

关键词： Elasticity

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Persistent robot tasking for environmental monitoring through crowd-sourcing

Persistent robot tasking for environmental monitoring throug...

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OCEANS

作者： Wesam Al-Sabban Jnaneshwar Das Ryan N. Smith School of Electrical Engineering and Computer Science Queensland University of Technology Brisbane QLD Australia Robotic Embedded Systems Laboratory University of Southern California Los Angeles CA Department of Engineering and Physics Fort Lewis College Durango CO USA

ISBN: (纸本)9781479913084

Persistent monitoring of the ocean is not optimally accomplished by repeatedly executing a fixed path in a fixed location. The ocean is dynamic, and so should the executed paths to monitor and observe it. An open question merging autonomy and optimal sampling is how and when to alter a path/decision, yet achieve desired science objectives. Additionally, many marine robotic deployments can last multiple weeks to months; making it very difficult for individuals to continuously monitor and retask them as needed. This problem becomes increasingly more complex when multiple platforms are operating simultaneously. There is a need for monitoring and adaptation of the robotic fleet via teams of scientists working in shifts; crowds are ideal for this task. In this paper, we present a novel application of crowd-sourcing to extend the autonomy of persistent-monitoring vehicles to enable non-repetitious sampling over long periods of time. We present a framework that enables the control of a marine robot by anybody with an internet-enabled device. Voters are provided current vehicle location, gathered science data and predicted ocean features through the associated decision support system. Results are included from a simulated implementation of our system on a Wave Glider operating in Monterey Bay with the science objective to maximize the sum of observed nitrate values collected.

关键词： Oceans Robots Monitoring Vehicles Vehicle dynamics Liquids Educational institutions

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Adaptive Fault Detection for Testing Tenant Applications in Multi-tenancy SaaS systems

Adaptive Fault Detection for Testing Tenant Applications in ...

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IEEE International Conference on Cloud engineering (IC2E)

作者： W.T. Tsai Qingyang Li Charles J. Colbourn Xiaoying Bai School of Computing Informatics and Decision Systems Engineering Arizona State University Tempe AZ USA State Key Laboratory of Software Development Environment Beihang University Beijing China Department of Computer Science and Technology Tsinghua University Beijing China

SaaS (Software-as-a-Service) often uses multi-tenancy architecture (MTA) where tenant developers compose their applications online using the components stored in the SaaS database. Tenant applications need to be tested, and combinatorial testing can be used. While numerous combinatorial testing techniques are available, most of them produce static sequences of test configurations and their goal is often to provide sufficient coverage such as 2-way interaction coverage. But the goal of SaaS testing is to identify those compositions that are faulty for tenant applications. This paper proposes an adaptive test configuration generation algorithm AR (Adaptive Reasoning) that can rapidly identify those faulty combinations so that those faulty combinations cannot be selected by tenant developers for composition. The AR algorithm has been evaluated by both simulation and real experimentation using a MTA SaaS sample running on GAE (Google App Engine). Both the simulation and experiment showed show that the AR algorithm can identify those faulty combinations rapidly. Whenever a new component is submitted to the SaaS database, the AR algorithm can be applied so that any faulty interactions with new components can be identified to continue to support future tenant applications.

关键词： Testing Software as a service Color Databases Image color analysis Fault location

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Complex Dynamical Behavior of a Two-Stage Colpitts Oscillator with Magnetically Coupled Inductors

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Journal of Chaos 2014年第1期2014卷

作者： V. Kamdoum Tamba H. B. Fotsin J. Kengne F. Kapche Tagne P. K. Talla Department of Physics Laboratory of Electronics and Signal Processing (LETS) Faculty of Science University of Dschang P.O. Box 67 Dschang *** Department of Telecommunication and Network Engineering IUT-Fotso Victor of Bandjoun University of Dschang P.O. Box 134 Bandjoun *** Department of Electrical Engineering Laboratory of Automation and Applied Computer (LAIA) IUT-Fotso Victor of Bandjoun University of Dschang P.O. Box 134 Bandjoun *** Department of Physics Laboratory of Mechanics and Modelling of Physical Systems (L2MPS) Faculty of Science University of Dschang P.O. Box 67 Dschang ***

A five-dimensional (5D) controlled two-stage Colpitts oscillator is introduced and analyzed. This new electronic oscillator is constructed by considering the well-known two-stage Colpitts oscillator with two further elements (coupled inductors and variable resistor). In contrast to current approaches based on piecewise linear (PWL) model, we propose a smooth mathematical model (with exponential nonlinearity) to investigate the dynamics of the oscillator. Several issues, such as the basic dynamical behaviour, bifurcation diagrams, Lyapunov exponents, and frequency spectra of the oscillator, are investigated theoretically and numerically by varying a single control resistor. It is found that the oscillator moves from the state of fixed point motion to chaos via the usual paths of period-doubling and interior crisis routes as the single control resistor is monitored. Furthermore, an experimental study of controlled Colpitts oscillator is carried out. An appropriate electronic circuit is proposed for the investigations of the complex dynamics behaviour of the system. A very good qualitative agreement is obtained between the theoretical/numerical and experimental results.

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Pricing Algorithms for the Day-Ahead Electricity Market with Flexible Consumer Participation

Pricing Algorithms for the Day-Ahead Electricity Market with...

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IEEE Conference on computer Communications Workshops

作者： Ozgur Dalkilic Ozan Candogan Atilla Eryilmaz Department of Electrical and Computer Engineering The Ohio State University Laboratory for Information and Decision Systems MIT

ISBN: (纸本)9781467359443

In this paper, we consider the design of the day-ahead market for the smart electrical grid. Consumers with flexible demand and generator companies participate in the market to settle on their load and supply schedules, respectively. The market is operated by an Independent System Operator (ISO) whose purpose is to maximize social welfare while keeping load and supply balanced in the electricity network. We develop two distributed pricing algorithms that achieve optimum welfare. The first algorithm yields time-dependent market prices under convexity assumptions on utility and cost functions and the second algorithm yields bundle prices for arbitrary utility and cost functions. In both algorithms, flexible consumers and generator companies simply determine their own schedules based on the prices updated by the ISO at each iteration. We show that the participation of flexible demand in the day-ahead market reduces supply volatility, which would be present when flexible demand does not take part in price setting procedure.

关键词： procedure determine flexible

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Loss Reduction via Network Reconfigurations in Distribution Networks with Photovoltaic Units Installed

Loss Reduction via Network Reconfigurations in Distribution ...

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International Conference on the European Energy Market

作者： A. S. Bouhouras T. A. Papadopoulos G. C. Christoforidis G. K. Papagiannis D. P. Labridis Department of Electrical Engineering Technological Education Institution of Western Macedonia Power Systems Laboratory Department of Electrical and Computer Engineering Aristotle University of Thessaloniki

ISBN: (纸本)9781479925582

The penetration of Renewable Energy Resources in Distribution Networks (DNs) is increasing rapidly, thus traditional issues regarding the DN operation should be faced through a different perspective that concerns dynamic behavior for both the distributed load consumption and power generation points of a network. Within this context, loss minimization in DNs by network reconfigurations should be examined subject to the variations regarding the load composition of the network due to the presence of Distributed Generation (DG) units. In this paper, the influence of Photovoltaic (PV) units installed in DNs to the optimal reconfiguration for loss reduction is investigated. The problem is stated, and a three level formulation is proposed in order to describe how the problem should be faced for an exhaustive and thorough analysis. Moreover, a simplified version of this proposed methodology is adopted in this work considering a two-stage sensitivity analysis: a spatial sensitivity analysis regarding the distribution of the PV units, and a quantitative sensitivity analysis concerning the penetration of the PV units in respect to the capacity of the network. The methodology is applied to three DNs by the published literature, and the results provide useful conclusions regarding the effect of the spatial distribution level along with the installed capacity of the PV units to the optimal reconfigured solution.

关键词： Distributed generation Loss reduction Network reconfiguration Photovoltaic units

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Modeling relative permittivity and electrical treeing in polymer nanocomposites

Modeling relative permittivity and electrical treeing in pol...

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IEEE International Conference on Solid Dielectrics

作者： D. Pitsa M. G. Danikas Department of Electrical and Computer Engineering Power Systems Laboratory Democritus University of Thrace Xanthi Greece

The interfaces, that are formed between the nanoparticles and the polymer in a polymer nanocomposite, are constituted from layers, which have different structure and characteristics than the polymer matrix. The role of interfaces in determining the dielectric properties is dominant, especially as interfaces of neighboring nanoparticles start to interact due to overlapping. This paper intents to model and determine the distribution of relative permittivity in a polymer nanocomposite. The calculation of the interface relative permittivity is based on the layers thickness and the exponential function. The layers thickness is determined by the multi-core model. Additionally, the electrical treeing in polymer nanocomposites is also modeled and the role of nanoparticles relative permittivity in treeing propagation is also discussed.

关键词： Polymer nanocomposites Dielectric properties Interface Permittivity electrical tree

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COMPRESSIVE SENSING-BASED IMAGE DENOISING USING ADAPTIVE MULTIPLE SAMPLING AND OPTIMAL ERROR TOLERANCE

COMPRESSIVE SENSING-BASED IMAGE DENOISING USING ADAPTIVE MUL...

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IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Wonseok Kang Eunsung Lee Eunjung Chea Aggelos K. Katsaggelos Joonki Paik Image Processing and Intelligent Systems Laboratory Graduate School of Advanced Imaging Science Multimedia and Film Seoul Chung-Ang University Korea Department of Electrical Engineering and Computer Science Northwestern University Evanston IL 60208 USA

ISBN: (纸本)9781479903573

In this paper, we present a compressive sensing-based image denoising algorithm using spatially adaptive image representation and estimation of optimal error tolerance based on sparse signal analysis. The proposed method performs block-based multiple compressive sampling after decomposing the sparse signal into feature and non-feature regions using simple statistical analysis. For minimization of recovery error and number of iterations, the modified OMP method estimates the optimal error tolerance using the average variance in the recovery step. Experimental results demonstrate that the proposed denoising algorithm better removes noise without undesired artifacts than existing state-of-the-art methods in terms of both objective (PSNR/SSIM) and subjective measures. Processing time of the proposed method is 5 to 10 times faster than the standard OMP-based method.

关键词： Tolerances physiologic tolerance Sampling system recovery image denoising image representation images Signal analysis Statistical analysis Statistical methods image denoising algorithm

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Quantum chaotic scattering in graphene systems in the absence of invariant classical dynamics

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Physical Review E 2013年第5期87卷 052908-052908页

作者： Guang-Lei Wang Lei Ying Ying-Cheng Lai Celso Grebogi School of Electrical Computer and Energy Engineering Arizona State University Tempe Arizona 85287 USA Department of Physics Arizona State University Tempe Arizona 85287 USA Institute for Complex Systems and Mathematical Biology School of Natural and Computing Sciences King's College University of Aberdeen Aberdeen AB24 3UE United Kingdom

Quantum chaotic scattering is referred to as the study of quantum behaviors of open Hamiltonian systems that exhibit transient chaos in the classical limit. Traditionally a central issue in this field is how the elements of the scattering matrix or their functions fluctuate as a system parameter, e.g., the electron Fermi energy, is changed. A tacit hypothesis underlying previous works was that the underlying classical phase-space structure remains invariant as the parameter varies, so semiclassical theory can be used to explain various phenomena in quantum chaotic scattering. There are, however, experimental situations where the corresponding classical chaotic dynamics can change characteristically with some physical parameter. Multiple-terminal quantum dots are one such example where, when a magnetic field is present, the classical chaotic-scattering dynamics can change between being nonhyperbolic and being hyperbolic as the Fermi energy is changed continuously. For such systems semiclassical theory is inadequate to account for the characteristics of conductance fluctuations with the Fermi energy. To develop a general framework for quantum chaotic scattering associated with variable classical dynamics, we use multi-terminal graphene quantum-dot systems as a prototypical model. We find that significant conductance fluctuations occur with the Fermi energy even for fixed magnetic field strength, and the characteristics of the fluctuation patterns depend on the energy. We propose and validate that the statistical behaviors of the conductance-fluctuation patterns can be understood by the complex eigenvalue spectrum of the generalized, complex Hamiltonian of the system which includes self-energies resulted from the interactions between the device and the semi-infinite leads. As the Fermi energy is increased, complex eigenvalues with extremely smaller imaginary parts emerge, leading to sharp resonances in the conductance.

关键词： QUANTUM chaos SCATTERING (Physics) GRAPHENE INVARIANTS (Mathematics) DYNAMICAL systems HAMILTONIAN systems PHASE space (Statistical physics) FERMIONS

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Giant Cross–Kerr Effect for Propagating Microwaves Induced by an Artificial Atom

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Physical Review Letters 2013年第5期111卷 053601-053601页

作者： Io-Chun Hoi Anton F. Kockum Tauno Palomaki Thomas M. Stace Bixuan Fan Lars Tornberg Sankar R. Sathyamoorthy Göran Johansson Per Delsing C. M. Wilson Department of Microtechnology and Nanoscience (MC2) Chalmers University of Technology SE-412 96 Göteborg Sweden Centre for Engineered Quantum Systems School of Physical Sciences University of Queensland Saint Lucia Queensland 4072 Australia Institute for Quantum Computing and Electrical and Computer Engineering Department University of Waterloo Waterloo N2L 3G1 Canada

We investigate the effective interaction between two microwave fields, mediated by a transmon-type superconducting artificial atom which is strongly coupled to a coplanar transmission line. The interaction between the fields and atom produces an effective cross–Kerr coupling. We demonstrate average cross–Kerr phase shifts of up to 20 degrees per photon with both coherent microwave fields at the single-photon level. Our results provide an important step toward quantum applications with propagating microwave photons.

关键词： MICROWAVE photonics ATOMS PARTICLE interactions KERR electro-optical effect SUPERCONDUCTING composites COPLANAR transmission lines SINGLE photon generation

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