Communication: Exciton–phonon information flow in the energy transfer process of photosynthetic complexes
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solar (photovoltaic), solid state lighting, photos↗
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Results for “INFORMATION FLOW”
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Information flow for security in control systems
This paper considers the development of information flow analyses to support resilient design and active detection of adversaries in cyber physical systems (CPS). CPS security, though well studied, suffers from fragmentation. In this paper, we consider control systems as an abstraction of CPS. Here, we use information flow analysis, a well established set of methods developed in software security, to obtain a unified framework that captures and extends results in control system security. Specifically, we propose the Kullback Liebler (KL) divergence as a causal measure of information flow, which quantifies the effect of adversarial inputs on sensor outputs. We show that the proposed measure characterizes the resilience of control systems to specific attack strategies by relating the KL divergence to optimal detection. We then relate information flows to stealthy attack scenarios where an adversary can bypass detection. Finally, this article examines active detection mechanisms where a defender intelligently manipulates control inputs or the system itself to elicit information flows from an attacker's malicious behavior. In all previous cases, we demonstrate an ability to investigate and extend existing results through the proposed information flow analyses.
Weerakkody, Sean↗
Information flow, non-Markovianity, and geometric phases
Geometric phases and information flows of a two-level system coupled to its environment are calculated and analyzed. The information flow is defined as a cumulant of changes in trace distance between two quantum states, which is similar to the measure for non-Markovianity given by Breuer. We obtain an analytic relation between the geometric phase and the information flow for pure initial states, and a numerical result for mixed initial states. The geometric phase behaves differently depending on whether there are information flows back to the two-level system from its environment.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Quantifying, characterizing, and controlling information flow in ultracold atomic gases
We study quantum information flow in a model comprised of a trapped impurity qubit immersed in a Bose-Einstein-condensed reservoir. We demonstrate how information flux between the qubit and the condensate can be manipulated by engineering the ultracold reservoir within experimentally realistic limits. We show that this system undergoes a transition from Markovian to non-Markovian dynamics, which can be controlled by changing key parameters such as the condensate scattering length. In this way, one can realize a quantum simulator of both Markovian and non-Markovian open quantum systems, the latter ones being characterized by a reverse flow of information from the background gas (reservoir) to the impurity (system).
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Content analysis in information flows
The paper deals with architecture of content recognition system. To analyze the problem the stochastic model of content recognition in information flows was built. We proved that under certain conditions it is possible to solve correctly a part of the problem with probability 1, viewing a finite section of the information flow. That means that good architecture consists of two steps. The first step determines correctly certain subsets of contents, while the second step may demand much more time for true decision.
97 MATHEMATICS AND COMPUTING↗
Information flow of quantum states interacting with closed timelike curves
Recently, the quantum information processing power of closed timelike curves has been discussed. Because the most widely accepted model for quantum closed timelike curve interactions contains ambiguities, different authors have been able to reach radically different conclusions as to the power of such interactions. By tracing the information flow through such systems we are able to derive equivalent circuits with unique solutions, thus allowing an objective decision between the alternatives to be made. We conclude that closed timelike curves, if they exist and are well described by these simple models, would be a powerful resource for quantum information processing.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Robust observations of land-to-atmosphere feedbacks using the information flows of FLUXNET
Feedbacks between atmospheric processes like precipitation and land surface fluxes including evapotranspiration are difficult to observe, but critical for understanding the role of the land surface in the Earth System. To quantify global surface-atmosphere feedbacks we use results of a process network (PN) applied to 251 eddy covariance sites from the LaThuile database to train a neural network across the global terrestrial surface. There is a strong land–atmosphere coupling between latent (LE) and sensible heat flux (H) and precipitation (P) during summer months in temperate regions, and between H and P during winter, whereas tropical rainforests show little coupling seasonality. Savanna, shrubland, and other semi-arid ecosystems exhibit strong responses in their coupling behavior based on water availability. Feedback couplings from surface fluxes to P peaks at aridity (P/potential evapotranspiration ET p ) values near unity, whereas coupling with respect to clouds, inferred from reduced global radiation, increases as P/ET p approaches zero. Spatial patterns in feedback coupling strength are related to climatic zone and biome type. Information flow statistics highlight hotspots of (1) persistent land–atmosphere coupling in sub-Saharan Africa, (2) boreal summer coupling in the central and southwestern US, Brazil, and the Congo basin and (3) in the southern Andes, South Africa and Australia during austral summer. Our data-driven approach to quantifying land atmosphere coupling strength that leverages the global FLUXNET database and information flow statistics provides a basis for verification of feedback interactions in general circulation models and for predicting locations where land cover change will feedback to climate or weather.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Information flows in strongly coupled ABJM theory
We use holographic methods to characterize the RG flow of quantum information in a Chern-Simons theory coupled to massive fermions. First, we use entanglement entropy and mutual information between strips to derive the dimension of the RG-driving operator and a monotonic c-function. We then display a scaling regime where, unlike in a CFT, the mutual information between strips changes non-monotonically with strip width, vanishing in both IR and UV but rising to a maximum at intermediate scales. The associated information transitions also contribute to non-monotonicity in the conditional mutual information which characterizes the independence of neighboring strips after conditioning on a third. Finally, we construct a measure of extensivity which tests to what extent information that region A shares with regions B and C is additive. In general, mutual information is super-extensive in holographic theories, and we might expect super-extensivity to be maximized in CFTs since they are scale-free. Surprisingly, our massive theory is more super-extensive than a CFT in a range of scales near the UV limit, although it is less super-extensive than a CFT at all lower scales. Our analysis requires the full ten-dimensional dual gravity background, and the extremal surfaces computing entanglement entropy explore all of these dimensions.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
On an interface of the online system for a stochastic analysis of the varied information flows
The article describes a possible approach to the construction of an interface of an online asynchronous system that allows researchers to analyse varied information flows. The implemented stochastic methods are based on the mixture models and the method of moving separation of mixtures. The general ideas of the system functionality are demonstrated on an example for some moments of a finite normal mixture.
97 MATHEMATICS AND COMPUTING↗
A Four-Layer Cyber-Physical Security Model for Electric Machine Drives Considering Control Information Flow
Despite the IEEE Power Electronics Society (PELS) establishing Technical Committee 10 on Design Methodologies with a focus on the cyber-physical security of power electronics systems, a holistic design methodology for addressing security vulnerabilities remains underdeveloped. This gap largely stems from the limited integration of computer science and power/control engineering studies in this interdisciplinary field. Addressing the inadequacy of unilateral cyber or control perspectives, this article presents a novel four-layer cyber-physical security model specifically designed for electric machine drives. Central to this model is the innovative control information flow (CIF) model, residing within the control layer, which serves as a pivotal link between the cyber layer's vulnerable resources and the physical layer's state-space models. By mapping vulnerable resources to control variable space and tracing attack propagation, the CIF model facilitates accurate impact predictions based on tainted control laws. The effectiveness and validity of this proposed model are demonstrated through hardware experiments involving two typical cyber-attack scenarios, underscoring its potential as a comprehensive framework for multidisciplinary security strategies.
97 MATHEMATICS AND COMPUTING↗
Quantum Fisher information flow and non-Markovian processes of open systems
We establish an information-theoretic approach for quantitatively characterizing the non-Markovianity of open quantum processes. Here, the quantum Fisher information (QFI) flow provides a measure to statistically distinguish Markovian and non-Markovian processes. A basic relation between the QFI flow and non-Markovianity is unveiled for quantum dynamics of open systems. For a class of time-local master equations, the exactly analytic solution shows that for each fixed time the QFI flow is decomposed into additive subflows according to different dissipative channels.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Modeling information flow in a computer processor with a multi-stage queuing model
In this paper, we introduce a nonlinear stochastic model to describe the propagation of information inside a computer processor. In this model, a computational task is divided into stages, and information can flow from one stage to another. The model is formulated as a spatially-extended, continuous-time Markov chain where space represents different stages. This model is equivalent to a spatially-extended version of the M/M/s queue. The main modeling feature is the throttling function which describes the processor slowdown when the amount of information falls below a certain threshold. We derive the stationary distribution for this stochastic model and develop a closure for a deterministic ODE system that approximates the evolution of the mean and variance of the stochastic model. In conclusion, we demonstrate the validity of the closure with numerical simulations.
97 MATHEMATICS AND COMPUTING↗
An Analysis of the Performance Bottlenecks in the Federated Search Information Flow
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99 GENERAL AND MISCELLANEOUS↗
Comment on ''Information flow of quantum states interacting with closed timelike curves''
We show that recent results on the interaction of causality-respecting particles with particles on closed timelike curves derived in [Phys. Rev. A 82, 062330 (2010)] depend on ambiguous assumptions about the form of the state which is inputted into the proposed equivalent circuit. Choosing a different form of this state leads to an opposite conclusion on the power of closed timelike curves.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Reply to ''Comment on 'Information flow of quantum states interacting with closed timelike curves'''
We respond to the comment by Klobus et al.[Phys. Rev. A 84, 056301 (2011)] by emphasizing that the equivalent circuit, once constructed, obeys the standard rules of quantum mechanics--hence there is no ambiguity in how to choose initial states in our model. We discuss the distinction between correlated ensembles produced nonlocally via measurements on entangled states and those produced via local preparation.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Mapping hydrologic and biogeochemical information flows to improve predictive models and understand climate influence
Focal area: Insights gleaned from complex data (both observed and simulated) using AI, big data analytics, and other advanced methods, including explainable AI and physics or knowledge-guide AI.
54 ENVIRONMENTAL SCIENCES↗
Information Flows in Reversible Computing Out of Equilibrium with Applications to Models of Topological Quantum Computing.
Abstract not provided.
Shukla, Karpur↗
Mobile phone collection, reuse and recycling in the UK
Highlights: > We characterized the key features of the voluntary UK mobile phone takeback network via a survey. > We identified 3 flows: information; product (handsets and accessories); and incentives. > There has been a significant rise in the number of UK takeback schemes since 1997. > Most returned handsets are low quality; little data exists on quantities of mobile phones collected. > Takeback schemes increasingly divert EoL mobile phones from landfill and enable reuse/recycling. - Abstract: Mobile phones are the most ubiquitous electronic product on the globe. They have relatively short lifecycles and because of their (perceived) in-built obsolescence, discarded mobile phones represent a significant and growing problem with respect to waste electrical and electronic equipment (WEEE). An emerging and increasingly important issue for industry is the shortage of key metals, especially the types of metals found in mobile phones, and hence the primary aim of this timely study was to assess and evaluate the voluntary mobile phone takeback network in the UK. The study has characterised the information, product and incentives flows in the voluntary UK mobile phone takeback network and reviewed the merits and demerits of the incentives offered. A survey of the activities of the voluntary mobile phone takeback schemes was undertaken in 2008 to: identify and evaluate the takeback schemes operating in the UK; determine the target groups from whom handsets are collected; and assess the collection, promotion and advertising methods used by the schemes. In addition, the survey sought to identify and critically evaluate the incentives offered by the takeback schemes, evaluate their ease and convenience of use; and determine the types, qualities and quantities of mobile phones they collect. The study has established that the UK voluntary mobile phone takeback network can be characterised as three distinctive flows: information flow; product flow (handsets and related accessories); and incentives flow. Over 100 voluntary schemes offering online takeback of mobile phone handsets were identified. The schemes are operated by manufacturers, retailers, mobile phone network service operators, charities and by mobile phone reuse, recycling and refurbishing companies. The latter two scheme categories offer the highest level of convenience and ease of use to their customers. Approximately 83% of the schemes are either for-profit/commercial-oriented and/or operate to raise funds for charities. The voluntary schemes use various methods to collect mobile phones from consumers, including postal services, courier and in-store. The majority of schemes utilise and finance pre-paid postage to collect handsets. Incentives offered by the takeback schemes include monetary payments, donation to charity and entry into prize draws. Consumers from whom handsets and related equipment are collected include individuals, businesses, schools, colleges, universities, charities and clubs with some schemes specialising on collecting handsets from one target group. The majority (84.3%) of voluntary schemes did not provide information on their websites about the quantities of mobile phones they collect. The operations of UK takeback schemes are decentralised in nature. Comparisons are made between the UK's decentralised collection system versus Australia's centralised network for collection of mobile phones. The significant principal conclusions from the study are: there has been a significant rise in the number of takeback schemes operating in the UK since the initial scheme was launched in 1997; the majority of returned handsets seem to be of low quality; and there is very little available information on the quantities of mobile phones collected by the various schemes. Irrespective of their financial motives, UK takeback schemes increasingly play an important role in sustainable waste management by diverting EoL mobile phones from landfills and encouraging reuse and recycling. Recommendations for future actions to improve the management of end-of-life mobile phone handsets and related accessories are made.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗