477,484 research outputs found
Complexity Reduction: Local Activity Ranking By Resource Entropy For QoS-aware Cloud Scheduling
The principle of local activity originated from electronic circuits, but can easily translate into other non-electrical homogeneous/heterogeneousmedia.Cloudresourceisanexample of a locally-active device, which is the origin of complexity in cloud scheduling system. However, most of the researchers implicitly assume the cloud resource to be locally passive when constructing new scheduling strategies. As a result, their research solutions perform poorly in the complex cloud environment. In this paper, we ?rst study several complexity factors caused by the locally-active cloud resource. And then we extended the âLocal Activity Principleâ concept with a quantitative measurement based on Entropy Theory. Furthermore, we classify the scheduling system into âOrderâ or âChaosâ state with simulating complexity in the cloud. Finally, we propose a new approach to controlling the chaos based on resourceâs Local Activity Ranking for QoS-aware cloud scheduling and implement such idea in Spark. Experiments demonstrate that our approach outperforms thenativeSparkFairSchedulerwithservercostreducedby23%, average response time improved by 15% - 20% and standard deviation of response time minimized by 30% - 45%
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Beyond Janus Geometry: Characterization of Flow Fields around Nonspherical Photocatalytic Microswimmers
Catalytic microswimmers that move by a phoretic mechanism in response to a self-induced chemical gradient are often obtained by the design of spherical janus microparticles, which suffer from multi-step fabrication and low yields. Approaches that circumvent laborious multi-step fabrication include the exploitation of the possibility of nonuniform catalytic activity along the surface of irregular particle shapes, local excitation or intrinsic asymmetry. Unfortunately, the effects on the generation of motion remain poorly understood. In this work, single crystalline BiVO4 microswimmers are presented that rely on a strict inherent asymmetry of charge-carrier distribution under illumination. The origin of the asymmetrical flow pattern is elucidated because of the high spatial resolution of measured flow fields around pinned BiVO4 colloids. As a result the flow from oxidative to reductive particle sides is confirmed. Distribution of oxidation and reduction reactions suggests a dominant self-electrophoretic motion mechanism with a source quadrupole as the origin of the induced flows. It is shown that the symmetry of the flow fields is broken by self-shadowing of the particles and synthetic surface defects that impact the photocatalytic activity of the microswimmers. The results demonstrate the complexity of symmetry breaking in nonspherical microswimmers and emphasize the role of self-shadowing for photocatalytic microswimmers. The findings are leading the way toward understanding of propulsion mechanisms of phoretic colloids of various shapes
Entropy4Cloud: Using Entropy-Based Complexity To Optimize Cloud Service Resource Management
In cloud service resource management system, complexity limits the systemâs ability to better satisfy the applicationâs QoS requirements, e.g. cost budget, average response time and reliability. Numerousness, diversity, variety, uncertainty, etc. are some of the complexity factors which lead to the variation between expected plan and actual running performance of cloud applications. In this paper, after defining the complexity clearly, we identify the origin of complexity in cloud service resource management system through the study of âLocal Activity Principleâ. In order to manage complexity, an Entropy-based methodology is presented to use which covers identifying, measuring, analysing and controlling (avoid and reduce) of complexity. Finally, we implement such idea in a popular cloud engine, Apache Spark, for running Analysis as a Service (AaaS). Experiments demonstrate that the new, Entropy-based resource management approach can significantly improve the performance of Spark applications. Compare with the Fair Scheduler in Apache Spark, our proposed Entropy Scheduler is able to reduce overall cost by 23%, improve the average service response time by 15% - 20% and minimized the standard deviation of service response time by 30% - 45%
Emerging Consciousness as a Result of Complex-Dynamical Interaction Process
A quite general interaction process within a multi-component system is analysed by the extended effective potential method, liberated from usual limitations of perturbation theory or integrable model. The obtained causally complete solution of the many-body problem reveals the phenomenon of dynamic multivaluedness, or redundance, of emerging, incompatible system realisations and dynamic entanglement of system components within each realisation. The ensuing concept of dynamic complexity (and related intrinsic chaoticity) is absolutely universal and can be applied to the problem of consciousness that emerges now as a high enough, properly specified level of unreduced complexity of a suitable interaction process. This complexity level can be identified with the appearance of bound, permanently localised states in the multivalued brain dynamics from strongly chaotic states of unconscious intelligence, by analogy with classical behaviour emergence from quantum states at much lower levels of world dynamics. We show that the main properties of this dynamically emerging consciousness (and intelligence, at the preceding complexity level) correspond to empirically derived properties of natural versions and obtain causally substantiated conclusions about their artificial realisation, including the fundamentally justified paradigm of genuine machine consciousness. This rigorously defined machine consciousness is different from both natural consciousness and any mechanistic, dynamically single-valued imitation of the latter. We use then the same, truly universal concept of complexity to derive equally rigorous conclusions about mental and social implications of the machine consciousness paradigm, demonstrating its indispensable role in the next stage of civilisation development
The Transitivity of Trust Problem in the Interaction of Android Applications
Mobile phones have developed into complex platforms with large numbers of
installed applications and a wide range of sensitive data. Application security
policies limit the permissions of each installed application. As applications
may interact, restricting single applications may create a false sense of
security for the end users while data may still leave the mobile phone through
other applications. Instead, the information flow needs to be policed for the
composite system of applications in a transparent and usable manner. In this
paper, we propose to employ static analysis based on the software architecture
and focused data flow analysis to scalably detect information flows between
components. Specifically, we aim to reveal transitivity of trust problems in
multi-component mobile platforms. We demonstrate the feasibility of our
approach with Android applications, although the generalization of the analysis
to similar composition-based architectures, such as Service-oriented
Architecture, can also be explored in the future
Analysis of electroencephalograms in Alzheimer's disease patients with multiscale entropy
The aim of this study was to analyse the electroencephalogram (EEG) background activity of Alzheimerâs disease (AD) patients using the Multiscale Entropy (MSE). The MSE is a recently developed method that quantifies the regularity of a signal on different time scales. These time scales are inspected by means of several coarse-grained sequences formed from the analysed signals. We recorded the EEGs from 19 scalp electrodes in 11 AD patients and 11 age-matched controls and estimated the MSE profile for each epoch of the EEG recordings. The shape of the MSE profiles reveals the EEG complexity, and it suggests that the EEG contains information in deeper scales than the smallest one. Moreover, the results showed that the EEG background activity is less complex in AD patients than control subjects. We found significant difference
Fractals in the Nervous System: conceptual Implications for Theoretical Neuroscience
This essay is presented with two principal objectives in mind: first, to
document the prevalence of fractals at all levels of the nervous system, giving
credence to the notion of their functional relevance; and second, to draw
attention to the as yet still unresolved issues of the detailed relationships
among power law scaling, self-similarity, and self-organized criticality. As
regards criticality, I will document that it has become a pivotal reference
point in Neurodynamics. Furthermore, I will emphasize the not yet fully
appreciated significance of allometric control processes. For dynamic fractals,
I will assemble reasons for attributing to them the capacity to adapt task
execution to contextual changes across a range of scales. The final Section
consists of general reflections on the implications of the reviewed data, and
identifies what appear to be issues of fundamental importance for future
research in the rapidly evolving topic of this review
Dislocation avalanche correlations
Recently, mechanical tests on ice as well as dislocation dynamics simulations
have revealed that plastic flow displays a scale-free intermittent dynamics
characterized by dislocation avalanches with a power law distribution of
amplitudes. To further explore the complexity of dislocation dynamics during
plastic flow, we present a statistical analysis of dislocation avalanche
correlations and avalanche triggering. It is shown that the rate of avalanche
triggering immediately after any avalanche is larger than the background
activity due to uncorrelated events. This self-induced triggering increases in
intensity, and remains over the background rate for longer times, as the
amplitude of the mainshock increases. This analysis suggests that stress
redistributions and the associated collective dislocation rearrangements may be
responsible for aftershock triggering in the complex process of plastic
deformation.Comment: 8 pages, 3 figures, presented at ICSMA-13, August 2003, Budapes
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