Science.gov

Sample records for stochastic ad allocation

  1. Stochastic optimisation of water allocation on a global scale

    NASA Astrophysics Data System (ADS)

    Schmitz, Oliver; Straatsma, Menno; Karssenberg, Derek; Bierkens, Marc F. P.

    2014-05-01

    Climate change, increasing population and further economic developments are expected to increase water scarcity for many regions of the world. Optimal water management strategies are required to minimise the water gap between water supply and domestic, industrial and agricultural water demand. A crucial aspect of water allocation is the spatial scale of optimisation. Blue water supply peaks at the upstream parts of large catchments, whereas demands are often largest at the industrialised downstream parts. Two extremes exist in water allocation: (i) 'First come, first serve,' which allows the upstream water demands to be fulfilled without considerations of downstream demands, and (ii) 'All for one, one for all' that satisfies water allocation over the whole catchment. In practice, water treaties govern intermediate solutions. The objective of this study is to determine the effect of these two end members on water allocation optimisation with respect to water scarcity. We conduct this study on a global scale with the year 2100 as temporal horizon. Water supply is calculated using the hydrological model PCR-GLOBWB, operating at a 5 arcminutes resolution and a daily time step. PCR-GLOBWB is forced with temperature and precipitation fields from the Hadgem2-ES global circulation model that participated in the latest coupled model intercomparison project (CMIP5). Water demands are calculated for representative concentration pathway 6.0 (RCP 6.0) and shared socio-economic pathway scenario 2 (SSP2). To enable the fast computation of the optimisation, we developed a hydrologically correct network of 1800 basin segments with an average size of 100 000 square kilometres. The maximum number of nodes in a network was 140 for the Amazon Basin. Water demands and supplies are aggregated to cubic kilometres per month per segment. A new open source implementation of the water allocation is developed for the stochastic optimisation of the water allocation. We apply a Genetic Algorithm for each segment to estimate the set of parameters that distribute the water supply for each node. We use the Python programming language and a flexible software architecture allowing to straightforwardly 1) exchange the process description for the nodes such that different water allocation schemes can be tested 2) exchange the objective function 3) apply the optimisation either to the whole catchment or to different sub-levels and 4) use multi-core CPUs concurrently and therefore reducing computation time. We demonstrate the application of the scientific workflow to the model outputs of PCR-GLOBWB and present first results on how water scarcity depends on the choice between the two extremes in water allocation.

  2. Constrained consumable resource allocation in alternative stochastic networks via multi-objective decision making

    NASA Astrophysics Data System (ADS)

    Hashemin, Seyed Saeid; Fatemi Ghomi, Seyed Mohammad Taghi

    2012-08-01

    Many real projects complete through the realization of one and only one path of various possible network paths. Here, these networks are called alternative stochastic networks (ASNs). It is supposed that the nodes of considered network are probabilistic with exclusive-or receiver and exclusive-or emitter. First, an analytical approach is proposed to simplify the structure of the network. This approach transforms the network into a simpler equivalent one. This paper discusses the constrained consumable resource allocation problem in an ASN. Many recent researchers apply heuristic and simulation methods to solve the constrained resource allocation in these problems. In this paper, we propose an analytical approach based on multi-objective modeling. The objective functions of this model are the cumulative distribution function of the completion time of ASN paths. These functions must be maximized within the desired network completion time. Lexicographic method is used to solve the proposed multi-objective model. The proposed method is illustrated by an example.

  3. Dynamic fair node spectrum allocation for ad hoc networks using random matrices

    NASA Astrophysics Data System (ADS)

    Rahmes, Mark; Lemieux, George; Chester, Dave; Sonnenberg, Jerry

    2015-05-01

    Dynamic Spectrum Access (DSA) is widely seen as a solution to the problem of limited spectrum, because of its ability to adapt the operating frequency of a radio. Mobile Ad Hoc Networks (MANETs) can extend high-capacity mobile communications over large areas where fixed and tethered-mobile systems are not available. In one use case with high potential impact, cognitive radio employs spectrum sensing to facilitate the identification of allocated frequencies not currently accessed by their primary users. Primary users own the rights to radiate at a specific frequency and geographic location, while secondary users opportunistically attempt to radiate at a specific frequency when the primary user is not using it. We populate a spatial radio environment map (REM) database with known information that can be leveraged in an ad hoc network to facilitate fair path use of the DSA-discovered links. Utilization of high-resolution geospatial data layers in RF propagation analysis is directly applicable. Random matrix theory (RMT) is useful in simulating network layer usage in nodes by a Wishart adjacency matrix. We use the Dijkstra algorithm for discovering ad hoc network node connection patterns. We present a method for analysts to dynamically allocate node-node path and link resources using fair division. User allocation of limited resources as a function of time must be dynamic and based on system fairness policies. The context of fair means that first available request for an asset is not envied as long as it is not yet allocated or tasked in order to prevent cycling of the system. This solution may also save money by offering a Pareto efficient repeatable process. We use a water fill queue algorithm to include Shapley value marginal contributions for allocation.

  4. Performance-based workload assessment: Allocation strategy and added task sensitivity

    NASA Technical Reports Server (NTRS)

    Vidulich, Michael A.

    1990-01-01

    The preliminary results of a research program investigating the use of added tasks to evaluate mental workload are reviewed. The focus of the first studies was a reappraisal of the traditional secondary task logic that encouraged the use of low-priority instructions for the added task. It was believed that such low-priority tasks would encourage subjects to split their available resources among the two tasks. The primary task would be assigned all the resources it needed, and any remaining reserve capacity would be assigned to the secondary task. If the model were correct, this approach was expected to combine sensitivity to primary task difficulty with unintrusiveness to primary task performance. The first studies of the current project demonstrated that a high-priority added task, although intrusive, could be more sensitive than the traditional low-priority secondary task. These results suggested that a more appropriate model of the attentional effects associated with added task performance might be based on capacity switching, rather than the traditional optimal allocation model.

  5. A dynamic programming approach to water allocation for seasonally dry area, based on stochastic soil moisture

    NASA Astrophysics Data System (ADS)

    Lu, Z.; Porporato, A. M.

    2012-12-01

    seasonally dry areas, which are widely distributed in the world, are usually facing an intensive disparity between the lack of natural resource and the great demand of social development. In dry seasons of such areas, the distribution/allocation of water resource is an extremely critical and sensitive issue, and conflicts often occur due to lack of appropriate water allocation scheme. Among the many uses of water, the need of agricultural irrigation water is highly elastic, but this factor has not yet been made full use to free up water from agriculture use. The primary goal of this work is to design an optimal distribution scheme of water resource for dry seasons to maximize benefits from precious water resources, considering the high elasticity of agriculture water demand due to the dynamic of soil moisture affected by the uncertainty of precipitation and other factors like canopy interception. A dynamic programming model will be used to figure out an appropriate allocation of water resources among agricultural irrigation and other purposes like drinking water, industry, and hydropower, etc. In this dynamic programming model, we analytically quantify the dynamic of soil moisture in the agricultural fields by describing the interception with marked Poisson process and describing the rainfall depth with exponential distribution. Then, we figure out a water-saving irrigation scheme, which regulates the timetable and volumes of water in irrigation, in order to minimize irrigation water requirement under the premise of necessary crop yield (as a constraint condition). And then, in turn, we provide a scheme of water resource distribution/allocation among agriculture and other purposes, taking aim at maximizing benefits from precious water resources, or in other words, make best use of limited water resource.

  6. Optimizing Real-Time Vaccine Allocation in a Stochastic SIR Model

    PubMed Central

    Nguyen, Chantal; Carlson, Jean M.

    2016-01-01

    Real-time vaccination following an outbreak can effectively mitigate the damage caused by an infectious disease. However, in many cases, available resources are insufficient to vaccinate the entire at-risk population, logistics result in delayed vaccine deployment, and the interaction between members of different cities facilitates a wide spatial spread of infection. Limited vaccine, time delays, and interaction (or coupling) of cities lead to tradeoffs that impact the overall magnitude of the epidemic. These tradeoffs mandate investigation of optimal strategies that minimize the severity of the epidemic by prioritizing allocation of vaccine to specific subpopulations. We use an SIR model to describe the disease dynamics of an epidemic which breaks out in one city and spreads to another. We solve a master equation to determine the resulting probability distribution of the final epidemic size. We then identify tradeoffs between vaccine, time delay, and coupling, and we determine the optimal vaccination protocols resulting from these tradeoffs. PMID:27043931

  7. Optimizing Real-Time Vaccine Allocation in a Stochastic SIR Model.

    PubMed

    Nguyen, Chantal; Carlson, Jean M

    2016-01-01

    Real-time vaccination following an outbreak can effectively mitigate the damage caused by an infectious disease. However, in many cases, available resources are insufficient to vaccinate the entire at-risk population, logistics result in delayed vaccine deployment, and the interaction between members of different cities facilitates a wide spatial spread of infection. Limited vaccine, time delays, and interaction (or coupling) of cities lead to tradeoffs that impact the overall magnitude of the epidemic. These tradeoffs mandate investigation of optimal strategies that minimize the severity of the epidemic by prioritizing allocation of vaccine to specific subpopulations. We use an SIR model to describe the disease dynamics of an epidemic which breaks out in one city and spreads to another. We solve a master equation to determine the resulting probability distribution of the final epidemic size. We then identify tradeoffs between vaccine, time delay, and coupling, and we determine the optimal vaccination protocols resulting from these tradeoffs. PMID:27043931

  8. Introducing health gains in location-allocation models: A stochastic model for planning the delivery of long-term care

    NASA Astrophysics Data System (ADS)

    Cardoso, T.; Oliveira, M. D.; Barbosa-Póvoa, A.; Nickel, S.

    2015-05-01

    Although the maximization of health is a key objective in health care systems, location-allocation literature has not yet considered this dimension. This study proposes a multi-objective stochastic mathematical programming approach to support the planning of a multi-service network of long-term care (LTC), both in terms of services location and capacity planning. This approach is based on a mixed integer linear programming model with two objectives - the maximization of expected health gains and the minimization of expected costs - with satisficing levels in several dimensions of equity - namely, equity of access, equity of utilization, socioeconomic equity and geographical equity - being imposed as constraints. The augmented ε-constraint method is used to explore the trade-off between these conflicting objectives, with uncertainty in the demand and delivery of care being accounted for. The model is applied to analyze the (re)organization of the LTC network currently operating in the Great Lisbon region in Portugal for the 2014-2016 period. Results show that extending the network of LTC is a cost-effective investment.

  9. Implementation of equity in resource allocation for regional earthquake risk mitigation using two-stage stochastic programming.

    PubMed

    Zolfaghari, Mohammad R; Peyghaleh, Elnaz

    2015-03-01

    This article presents a new methodology to implement the concept of equity in regional earthquake risk mitigation programs using an optimization framework. It presents a framework that could be used by decisionmakers (government and authorities) to structure budget allocation strategy toward different seismic risk mitigation measures, i.e., structural retrofitting for different building structural types in different locations and planning horizons. A two-stage stochastic model is developed here to seek optimal mitigation measures based on minimizing mitigation expenditures, reconstruction expenditures, and especially large losses in highly seismically active countries. To consider fairness in the distribution of financial resources among different groups of people, the equity concept is incorporated using constraints in model formulation. These constraints limit inequity to the user-defined level to achieve the equity-efficiency tradeoff in the decision-making process. To present practical application of the proposed model, it is applied to a pilot area in Tehran, the capital city of Iran. Building stocks, structural vulnerability functions, and regional seismic hazard characteristics are incorporated to compile a probabilistic seismic risk model for the pilot area. Results illustrate the variation of mitigation expenditures by location and structural type for buildings. These expenditures are sensitive to the amount of available budget and equity consideration for the constant risk aversion. Most significantly, equity is more easily achieved if the budget is unlimited. Conversely, increasing equity where the budget is limited decreases the efficiency. The risk-return tradeoff, equity-reconstruction expenditures tradeoff, and variation of per-capita expected earthquake loss in different income classes are also presented. PMID:25676412

  10. Investigation and incorporation of water inflow uncertainties through stochastic modelling in a combined optimisation methodology for water allocation in Alfeios River (Greece)

    NASA Astrophysics Data System (ADS)

    Bekri, Eleni; Yannopoulos, Panayotis; Disse, Markus

    2014-05-01

    The Alfeios River plays a vital role for Western Peloponnisos in Greece from natural, ecological, social and economic aspect. The main river and its six tributaries, forming the longest watercourse and the highest streamflow rate of Peloponnisose, represent a significant source of water supply for the region, aiming at delivering and satisfying the expected demands from a variety of water users, including irrigation, drinking water supply, hydropower production and recreation. In the previous EGU General Assembly, a fuzzy-boundary-interval linear programming methodology, based on Li et al. (2010) and Bekri et al. (2012), has been presented for optimal water allocation under uncertain and vague system conditions in the Alfeios River Basin. Uncertainties associated with the benefit and cost coefficient in the objective function of the main water uses (hydropower production and irrigation) were expressed as probability distributions and fuzzy boundary intervals derived by associated α-cut levels. The uncertainty of the monthly water inflows was not incorporated in the previous initial application and the analysis of all other sources of uncertainty has been applied to two extreme hydrologic years represented by a selected wet and dry year. To manage and operate the river system, decision makers should be able to analyze and evaluate the impact of various hydrologic scenarios. In the present work, the critical uncertain parameter of water inflows is analyzed and its incorporation as an additional type of uncertainty in the suggested methodology is investigated, in order to enable the assessment of optimal water allocation for hydrologic and socio-economic scenarios based both on historical data and projected climate change conditions. For this purpose, stochastic simulation analysis for a part of the Alfeios river system is undertaken, testing various stochastic models from simple stationary ones (AR and ARMA), Thomas-Fiering, ARIMA as well as more sophisticated and complete such as CASTALIA. A short description and comparison of their assumptions, the differences between them and the presentation of the results are included. Li, Y.P., Huang, G.H. and S.L., Nie, (2010), Planning water resources management systems using a fuzzy boundary interval-stochastic programming method, Elsevier Ltd, Advances in Water Resources, 33: 1105-1117. doi:10.1016/j.advwatres.2010.06.015 Bekri, E.S., Disse, M. and P.C.,Yannopoulos, (2012), Methodological framework for correction of quick river discharge measurements using quality characteristics, Session of Environmental Hydraulics - Hydrodynamics, 2nd Common Conference of Hellenic Hydrotechnical Association and Greek Committee for Water Resources Management, Volume: 546-557 (in Greek).

  11. Stochastic games.

    PubMed

    Solan, Eilon; Vieille, Nicolas

    2015-11-10

    In 1953, Lloyd Shapley contributed his paper "Stochastic games" to PNAS. In this paper, he defined the model of stochastic games, which were the first general dynamic model of a game to be defined, and proved that it admits a stationary equilibrium. In this Perspective, we summarize the historical context and the impact of Shapley's contribution. PMID:26556883

  12. Stochastic games

    PubMed Central

    Solan, Eilon; Vieille, Nicolas

    2015-01-01

    In 1953, Lloyd Shapley contributed his paper “Stochastic games” to PNAS. In this paper, he defined the model of stochastic games, which were the first general dynamic model of a game to be defined, and proved that it admits a stationary equilibrium. In this Perspective, we summarize the historical context and the impact of Shapley’s contribution. PMID:26556883

  13. Stochastic resonance

    NASA Astrophysics Data System (ADS)

    Gammaitoni, Luca; Hänggi, Peter; Jung, Peter; Marchesoni, Fabio

    1998-01-01

    Over the last two decades, stochastic resonance has continuously attracted considerable attention. The term is given to a phenomenon that is manifest in nonlinear systems whereby generally feeble input information (such as a weak signal) can be be amplified and optimized by the assistance of noise. The effect requires three basic ingredients: (i) an energetic activation barrier or, more generally, a form of threshold; (ii) a weak coherent input (such as a periodic signal); (iii) a source of noise that is inherent in the system, or that adds to the coherent input. Given these features, the response of the system undergoes resonance-like behavior as a function of the noise level; hence the name stochastic resonance. The underlying mechanism is fairly simple and robust. As a consequence, stochastic resonance has been observed in a large variety of systems, including bistable ring lasers, semiconductor devices, chemical reactions, and mechanoreceptor cells in the tail fan of a crayfish. In this paper, the authors report, interpret, and extend much of the current understanding of the theory and physics of stochastic resonance. They introduce the readers to the basic features of stochastic resonance and its recent history. Definitions of the characteristic quantities that are important to quantify stochastic resonance, together with the most important tools necessary to actually compute those quantities, are presented. The essence of classical stochastic resonance theory is presented, and important applications of stochastic resonance in nonlinear optics, solid state devices, and neurophysiology are described and put into context with stochastic resonance theory. More elaborate and recent developments of stochastic resonance theory are discussed, ranging from fundamental quantum properties-being important at low temperatures-over spatiotemporal aspects in spatially distributed systems, to realizations in chaotic maps. In conclusion the authors summarize the achievements and attempt to indicate the most promising areas for future research in theory and experiment.

  14. Stochastic resonance and computation

    NASA Astrophysics Data System (ADS)

    Torres, José-Leonel; Trainor, Lynn

    1997-09-01

    Stochastic resonance (SR) occurs in bistable nonlinear systems subject to noise, as the entrainment of their output by a weak periodic modulation added to the input. Electronic computation involves switching of memory elements between two states that correspond to 1 and 0, respectively. The possibility of switching errors due to SR in memory elements is considered, showing that it represents a negligible danger to reliable computation.

  15. Computer Processor Allocator

    Energy Science and Technology Software Center (ESTSC)

    2004-03-01

    The Compute Processor Allocator (CPA) provides an efficient and reliable mechanism for managing and allotting processors in a massively parallel (MP) computer. It maintains information in a database on the health. configuration and allocation of each processor. This persistent information is factored in to each allocation decision. The CPA runs in a distributed fashion to avoid a single point of failure.

  16. Stochastic cooling

    SciTech Connect

    Bisognano, J.; Leemann, C.

    1982-03-01

    Stochastic cooling is the damping of betatron oscillations and momentum spread of a particle beam by a feedback system. In its simplest form, a pickup electrode detects the transverse positions or momenta of particles in a storage ring, and the signal produced is amplified and applied downstream to a kicker. The time delay of the cable and electronics is designed to match the transit time of particles along the arc of the storage ring between the pickup and kicker so that an individual particle receives the amplified version of the signal it produced at the pick-up. If there were only a single particle in the ring, it is obvious that betatron oscillations and momentum offset could be damped. However, in addition to its own signal, a particle receives signals from other beam particles. In the limit of an infinite number of particles, no damping could be achieved; we have Liouville's theorem with constant density of the phase space fluid. For a finite, albeit large number of particles, there remains a residue of the single particle damping which is of practical use in accumulating low phase space density beams of particles such as antiprotons. It was the realization of this fact that led to the invention of stochastic cooling by S. van der Meer in 1968. Since its conception, stochastic cooling has been the subject of much theoretical and experimental work. The earliest experiments were performed at the ISR in 1974, with the subsequent ICE studies firmly establishing the stochastic cooling technique. This work directly led to the design and construction of the Antiproton Accumulator at CERN and the beginnings of p anti p colliding beam physics at the SPS. Experiments in stochastic cooling have been performed at Fermilab in collaboration with LBL, and a design is currently under development for a anti p accumulator for the Tevatron.

  17. Stochastic thermodynamics

    NASA Astrophysics Data System (ADS)

    Eichhorn, Ralf; Aurell, Erik

    2014-04-01

    'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response theory for small deviations from equilibrium, in which a general framework is constructed from the analysis of non-equilibrium states close to equilibrium. In a next step, Prigogine and others developed linear irreversible thermodynamics, which establishes relations between transport coefficients and entropy production on a phenomenological level in terms of thermodynamic forces and fluxes. However, beyond the realm of linear response no general theoretical results were available for quite a long time. This situation has changed drastically over the last 20 years with the development of stochastic thermodynamics, revealing that the range of validity of thermodynamic statements can indeed be extended deep into the non-equilibrium regime. Early developments in that direction trace back to the observations of symmetry relations between the probabilities for entropy production and entropy annihilation in non-equilibrium steady states [5-8] (nowadays categorized in the class of so-called detailed fluctuation theorems), and the derivations of the Bochkov-Kuzovlev [9, 10] and Jarzynski relations [11] (which are now classified as so-called integral fluctuation theorems). Apart from its fundamental theoretical interest, the developments in stochastic thermodynamics have experienced an additional boost from the recent experimental progress in fabricating, manipulating, controlling and observing systems on the micro- and nano-scale. These advances are not only of formidable use for probing and monitoring biological processes on the cellular, sub-cellular and molecular level, but even include the realization of a microscopic thermodynamic heat engine [12] or the experimental verification of Landauer's principle in a colloidal system [13]. The scientific program Stochastic Thermodynamics held between 4 and 15 March 2013, and hosted by The Nordic Institute for Theoretical Physics (Nordita), was attended by more than 50 scientists from the Nordic countries and elsewhere, amongst them many leading experts in the field. During the program, the most recent developments, open questions and new ideas in stochastic thermodynamics were presented and discussed. From the talks and debates, the notion of information in stochastic thermodynamics, the fundamental properties of entropy production (rate) in non-equilibrium, the efficiency of small thermodynamic machines and the characteristics of optimal protocols for the applied (cyclic) forces were crystallizing as main themes. Surprisingly, the long-studied adiabatic piston, its peculiarities and its relation to stochastic thermodynamics were also the subject of intense discussions. The comment on the Nordita program Stochastic Thermodynamics published in this issue of Physica Scripta exploits the Jarzynski relation for determining free energy differences in the adiabatic piston. This scientific program and the contribution presented here were made possible by the financial and administrative support of The Nordic Institute for Theoretical Physics.

  18. Value Added?

    ERIC Educational Resources Information Center

    UCLA IDEA, 2012

    2012-01-01

    Value added measures (VAM) uses changes in student test scores to determine how much "value" an individual teacher has "added" to student growth during the school year. Some policymakers, school districts, and educational advocates have applauded VAM as a straightforward measure of teacher effectiveness: the better a teacher, the better students…

  19. Channel Allocation Options.

    ERIC Educational Resources Information Center

    Powers, Robert S.

    The Frequency Allocation Subcommittee of the Coordinating Committee for Cable Communication Systems, Institute of Electrical and Electronic Engineers, was formed to produce a background report on the general problems of frequency allocation and assignments in cable television. The present paper, based on the subcommittee's interim report,…

  20. Allocation without locking

    SciTech Connect

    Appel, A.W.

    1988-01-01

    In a programming environment with both concurrency and automatic garbage collection, the allocation and initialization of a new record is a sensitive matter: if it is interrupted halfway through, the allocating process may be in a state that the garbage collector can't understand. In particular, the collector won't know which words of the new record have been initialized and which are meaningless (and unsafe to transverse). For this reason, parallel implementations usually use a locking or semaphore mechanism to ensure that allocation is an atomic operation. The locking significantly adds to the cost of allocation. This paper shows that allocation can run extremely quickly even in a multi-thread environment: open-coded, without locking.

  1. Added Sugars

    MedlinePlus

    ... fruit punch); dairy desserts and milk products (ice cream, sweetened yogurt and sweetened milk); and other grains ( ... Tips for Reducing Sugar in Your Diet Simple Cooking with Heart Added Sugar is not so Sweet ...

  2. Sensory Optimization by Stochastic Tuning

    PubMed Central

    Jurica, Peter; Gepshtein, Sergei; Tyukin, Ivan; van Leeuwen, Cees

    2013-01-01

    Individually, visual neurons are each selective for several aspects of stimulation, such as stimulus location, frequency content, and speed. Collectively, the neurons implement the visual system’s preferential sensitivity to some stimuli over others, manifested in behavioral sensitivity functions. We ask how the individual neurons are coordinated to optimize visual sensitivity. We model synaptic plasticity in a generic neural circuit, and find that stochastic changes in strengths of synaptic connections entail fluctuations in parameters of neural receptive fields. The fluctuations correlate with uncertainty of sensory measurement in individual neurons: the higher the uncertainty the larger the amplitude of fluctuation. We show that this simple relationship is sufficient for the stochastic fluctuations to steer sensitivities of neurons toward a characteristic distribution, from which follows a sensitivity function observed in human psychophysics, and which is predicted by a theory of optimal allocation of receptive fields. The optimal allocation arises in our simulations without supervision or feedback about system performance and independently of coupling between neurons, making the system highly adaptive and sensitive to prevailing stimulation. PMID:24219849

  3. Stochastic Cooling

    SciTech Connect

    Blaskiewicz, M.

    2011-01-01

    Stochastic Cooling was invented by Simon van der Meer and was demonstrated at the CERN ISR and ICE (Initial Cooling Experiment). Operational systems were developed at Fermilab and CERN. A complete theory of cooling of unbunched beams was developed, and was applied at CERN and Fermilab. Several new and existing rings employ coasting beam cooling. Bunched beam cooling was demonstrated in ICE and has been observed in several rings designed for coasting beam cooling. High energy bunched beams have proven more difficult. Signal suppression was achieved in the Tevatron, though operational cooling was not pursued at Fermilab. Longitudinal cooling was achieved in the RHIC collider. More recently a vertical cooling system in RHIC cooled both transverse dimensions via betatron coupling.

  4. Immigration-extinction dynamics of stochastic populations

    NASA Astrophysics Data System (ADS)

    Meerson, Baruch; Ovaskainen, Otso

    2013-07-01

    How high should be the rate of immigration into a stochastic population in order to significantly reduce the probability of observing the population become extinct? Is there any relation between the population size distributions with and without immigration? Under what conditions can one justify the simple patch occupancy models, which ignore the population distribution and its dynamics in a patch, and treat a patch simply as either occupied or empty? We answer these questions by exactly solving a simple stochastic model obtained by adding a steady immigration to a variant of the Verhulst model: a prototypical model of an isolated stochastic population.

  5. 26 CFR 1.338-7 - Allocation of redetermined ADSP and AGUB among target assets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... allocation of the redetermined ADSP or AGUB amount under § 1.338-6 to a given asset is different from the... date asset) are subject to all the asset allocation rules (for example, the fair market value... depleted by new target before an amount is added to the original allocation to the asset, the...

  6. Adding Value.

    ERIC Educational Resources Information Center

    Orsini, Larry L.; Hudack, Lawrence R.; Zekan, Donald L.

    1999-01-01

    The value-added statement (VAS), relatively unknown in the United States, is used in financial reports by many European companies. Saint Bonaventure University (New York) has adapted a VAS to make it appropriate for not-for-profit universities by identifying stakeholder groups (students, faculty, administrators/support personnel, creditors, the…

  7. The Unobtrusive Memory Allocator

    Energy Science and Technology Software Center (ESTSC)

    2003-03-31

    This library implements a memory allocator/manager which ask its host program or library for memory refions to manage rather than requesting them from the operating system. This allocator supports multiple distinct heaps within a single executable, each of which may grow either upward or downward in memory. The GNU mmalloc library has been modified in such a way that its allocation algorithms have been preserved, but the manner in which it obtains regions to managemore » has been changed to request memory from the host program or library. Additional modifications allow the allocator to manage each heap as either upward or downward-growing. By allowing the hosting program or library to determine what memory is managed, this package allows a greater degree of control than other memory allocation/management libraries. Additional distinguishing features include the ability to manage multiple distinct heaps with in a single executable, each of which may grow either upward or downward in memory. The most common use of this library is in conjunction with the Berkeley Unified Parallel C (UPC) Runtime Library. This package is a modified version of the LGPL-licensed "mmalloc" allocator from release 5.2 of the "gdb" debugger's source code.« less

  8. The Effective Use of Student Time: A Stochastic Frontier Production Function Case Study

    ERIC Educational Resources Information Center

    Dolton, Peter; Marcenaro, Oscar D.; Navarro, Lucia

    2003-01-01

    The relationship between student study time allocation and examination performance is little understood. We model the allocation of student time into formal study (lectures and classes) and self study and its relationship to university examination scores using a stochastic frontier production function. This case study uses unique time budget data…

  9. The kidney allocation system.

    PubMed

    Friedewald, John J; Samana, Ciara J; Kasiske, Bertram L; Israni, Ajay K; Stewart, Darren; Cherikh, Wida; Formica, Richard N

    2013-12-01

    The current kidney allocation system for transplants is outdated and has not evolved to reflect the changing demographics of patients on the waiting list. This article proposes a new system for kidney allocation, which more appropriately incorporates the biology of highly sensitized patients into the waiting-time scoring algorithm. This system will significantly reduce mismatches between possible donor kidney longevity and life expectancy of recipients, and makes incremental advances toward more geographic sharing. The proposed system makes significant progress toward eliminating deficiencies in the current system, and has the potential to increase the supply of available kidneys. PMID:24206858

  10. A Framework for Optimal Control Allocation with Structural Load Constraints

    NASA Technical Reports Server (NTRS)

    Frost, Susan A.; Taylor, Brian R.; Jutte, Christine V.; Burken, John J.; Trinh, Khanh V.; Bodson, Marc

    2010-01-01

    Conventional aircraft generally employ mixing algorithms or lookup tables to determine control surface deflections needed to achieve moments commanded by the flight control system. Control allocation is the problem of converting desired moments into control effector commands. Next generation aircraft may have many multipurpose, redundant control surfaces, adding considerable complexity to the control allocation problem. These issues can be addressed with optimal control allocation. Most optimal control allocation algorithms have control surface position and rate constraints. However, these constraints are insufficient to ensure that the aircraft's structural load limits will not be exceeded by commanded surface deflections. In this paper, a framework is proposed to enable a flight control system with optimal control allocation to incorporate real-time structural load feedback and structural load constraints. A proof of concept simulation that demonstrates the framework in a simulation of a generic transport aircraft is presented.

  11. Stochastic cooling in RHIC

    SciTech Connect

    Brennan,J.M.; Blaskiewicz, M. M.; Severino, F.

    2009-05-04

    After the success of longitudinal stochastic cooling of bunched heavy ion beam in RHIC, transverse stochastic cooling in the vertical plane of Yellow ring was installed and is being commissioned with proton beam. This report presents the status of the effort and gives an estimate, based on simulation, of the RHIC luminosity with stochastic cooling in all planes.

  12. Approaches to Resource Allocation

    ERIC Educational Resources Information Center

    Dressel, Paul; Simon, Lou Anna Kimsey

    1976-01-01

    Various budgeting patterns and strategies are currently in use, each with its own particular strengths and weaknesses. Neither cost-benefit analysis nor cost-effectiveness analysis offers any better solution to the allocation problem than do the unsupported contentions of departments or the historical unit costs. An operable model that performs…

  13. Stochastic gradient method with accelerated stochastic dynamics

    NASA Astrophysics Data System (ADS)

    Ohzeki, Masayuki

    2016-03-01

    We implement the simple method to accelerate the convergence speed to the steady state and enhance the mixing rate to the stochastic gradient Langevin method. The ordinary stochastic gradient method is based on mini-batch learning for reducing the computational cost when the amount of data is extraordinary large. The stochasticity of the gradient can be mitigated by the injection of Gaussian noise, which yields the stochastic Langevin gradient method; this method can be used for Bayesian posterior sampling. However, the performance of the stochastic Langevin gradient method depends on the mixing rate of the stochastic dynamics. In this study, we propose violating the detailed balance condition to enhance the mixing rate. Recent studies have revealed that violating the detailed balance condition accelerates the convergence to a stationary state and reduces the correlation time between the samplings. We implement this violation of the detailed balance condition in the stochastic gradient Langevin method and test our method for a simple model to demonstrate its performance.

  14. Stochastic symmetries of Wick type stochastic ordinary differential equations

    NASA Astrophysics Data System (ADS)

    Ünal, Gazanfer

    2015-04-01

    We consider Wick type stochastic ordinary differential equations with Gaussian white noise. We define the stochastic symmetry transformations and Lie equations in Kondratiev space (S)-1N. We derive the determining system of Wick type stochastic partial differential equations with Gaussian white noise. Stochastic symmetries for stochastic Bernoulli, Riccati and general stochastic linear equation in (S)-1N are obtained. A stochastic version of canonical variables is also introduced.

  15. Spectrum allocations above 40 GHz

    NASA Technical Reports Server (NTRS)

    Katzenstein, W. E.; Moore, R. P.; Kimball, H. G.

    1981-01-01

    The 1979 World Administrative Radio Conference (WARC-79) revised the International Table of Frequency Allocations to reflect increased interest and activity in the region of the EM spectrum above 40 GHz. The total width of the spectrum allocated (235 GHz) in the region above 40 GHz indicates the extent of this new spectrum resource, made accessible by advances in the state-of-the-art of telecommunications equipment. There are some striking differences between the approach to allocation above and below 40 GHz. For example, there are not bands allocated exclusively. This reflects the characteristics of propagation and the small antenna beamwidths achievable at these frequencies. Attention is given to atmospheric window and absorption band limits, allocations to satellite services, allocations to scientific services, allocations to terrestrial services, the future refinement of the radio regulations above 40 GHz, and allocations of WARC-79 and frequency management.

  16. Spectrum allocations above 40 GHz

    NASA Astrophysics Data System (ADS)

    Katzenstein, W. E.; Moore, R. P.; Kimball, H. G.

    1981-08-01

    The 1979 World Administrative Radio Conference (WARC-79) revised the International Table of Frequency Allocations to reflect increased interest and activity in the region of the EM spectrum above 40 GHz. The total width of the spectrum allocated (235 GHz) in the region above 40 GHz indicates the extent of this new spectrum resource, made accessible by advances in the state-of-the-art of telecommunications equipment. There are some striking differences between the approach to allocation above and below 40 GHz. For example, there are not bands allocated exclusively. This reflects the characteristics of propagation and the small antenna beamwidths achievable at these frequencies. Attention is given to atmospheric window and absorption band limits, allocations to satellite services, allocations to scientific services, allocations to terrestrial services, the future refinement of the radio regulations above 40 GHz, and allocations of WARC-79 and frequency management.

  17. Economics of spectrum allocation

    NASA Astrophysics Data System (ADS)

    Melody, W. H.

    The effective and efficient allocation and use of the spectrum can be ensured only by a set of sharing rules that will reflect the interests, values, and power of all affected parties. What is now happening is that the new interests and different values of the developing countries are pressing to change the international sharing rules established by a small group of high-technology nations. It is noted that the latter have established a massive telecommunications infrastructure on the basis of inherited sharing rules that reflect only their interests and a much simplified scarcity problem. Once long-term goals and underlying principles of allocation are established, communication technologies and markets can be directed, through a series of adjustment policies, to achieve them. A crucial first step in the creation of an international information environment in which 'free' flows will be balanced flows is the establishment of a balanced and equitable set of sharing rules for the radio spectrum.

  18. Myrmics Memory Allocator

    Energy Science and Technology Software Center (ESTSC)

    2011-09-23

    MMA is a stand-alone memory management system for MPI clusters. It implements a shared Partitioned Global Address Space, where multiple MPI processes request objects from the allocator and the latter provides them with system-wide unique memory addresses for each object. It provides applications with an intuitive way of managing the memory system in a unified way, thus enabling easier writing of irregular application code.

  19. Attention allocation before antisaccades.

    PubMed

    Klapetek, Anna; Jonikaitis, Donatas; Deubel, Heiner

    2016-01-01

    In the present study, we investigated the distribution of attention before antisaccades. We used a dual task paradigm, in which participants made prosaccades or antisaccades and discriminated the orientation of a visual probe shown at the saccade goal, the visual cue location (antisaccade condition), or a neutral location. Moreover, participants indicated whether they had made a correct antisaccade or an erroneous prosaccade. We observed that, while spatial attention in the prosaccade task was allocated only to the saccade goal, attention in the antisaccade task was allocated both to the cued location and to the antisaccade goal. This suggests parallel attentional selection of the cued and antisaccade locations. We further observed that in error trials--in which participants made an incorrect prosaccade instead of an antisaccade--spatial attention was biased towards the prosaccade goal. These erroneous prosaccades were mostly unnoticed and were often followed by corrective antisaccades with very short latencies (<100 ms). Data from error trials therefore provide further evidence for the parallel programming of the reflexive prosaccade to the cue and the antisaccade to the intended location. Taken together, our results suggest that attention allocation and saccade goal selection in the antisaccade task are mediated by a common competitive process. PMID:26790843

  20. Fluctuations as stochastic deformation.

    PubMed

    Kazinski, P O

    2008-04-01

    A notion of stochastic deformation is introduced and the corresponding algebraic deformation procedure is developed. This procedure is analogous to the deformation of an algebra of observables like deformation quantization, but for an imaginary deformation parameter (the Planck constant). This method is demonstrated on diverse relativistic and nonrelativistic models with finite and infinite degrees of freedom. It is shown that under stochastic deformation the model of a nonrelativistic particle interacting with the electromagnetic field on a curved background passes into the stochastic model described by the Fokker-Planck equation with the diffusion tensor being the inverse metric tensor. The first stochastic correction to the Newton equations for this system is found. The Klein-Kramers equation is also derived as the stochastic deformation of a certain classical model. Relativistic generalizations of the Fokker-Planck and Klein-Kramers equations are obtained by applying the procedure of stochastic deformation to appropriate relativistic classical models. The analog of the Fokker-Planck equation associated with the stochastic Lorentz-Dirac equation is derived too. The stochastic deformation of the models of a free scalar field and an electromagnetic field is investigated. It turns out that in the latter case the obtained stochastic model describes a fluctuating electromagnetic field in a transparent medium. PMID:18517590

  1. Fluctuations as stochastic deformation

    NASA Astrophysics Data System (ADS)

    Kazinski, P. O.

    2008-04-01

    A notion of stochastic deformation is introduced and the corresponding algebraic deformation procedure is developed. This procedure is analogous to the deformation of an algebra of observables like deformation quantization, but for an imaginary deformation parameter (the Planck constant). This method is demonstrated on diverse relativistic and nonrelativistic models with finite and infinite degrees of freedom. It is shown that under stochastic deformation the model of a nonrelativistic particle interacting with the electromagnetic field on a curved background passes into the stochastic model described by the Fokker-Planck equation with the diffusion tensor being the inverse metric tensor. The first stochastic correction to the Newton equations for this system is found. The Klein-Kramers equation is also derived as the stochastic deformation of a certain classical model. Relativistic generalizations of the Fokker-Planck and Klein-Kramers equations are obtained by applying the procedure of stochastic deformation to appropriate relativistic classical models. The analog of the Fokker-Planck equation associated with the stochastic Lorentz-Dirac equation is derived too. The stochastic deformation of the models of a free scalar field and an electromagnetic field is investigated. It turns out that in the latter case the obtained stochastic model describes a fluctuating electromagnetic field in a transparent medium.

  2. Stochastic phase transition operator.

    PubMed

    Yamanobe, Takanobu

    2011-07-01

    In this study a Markov operator is introduced that represents the density evolution of an impulse-driven stochastic biological oscillator. The operator's stochastic kernel is constructed using the asymptotic expansion of stochastic processes instead of solving the Fokker-Planck equation. The Markov operator is shown to successfully approximate the density evolution of the biological oscillator considered. The response of the oscillator to both periodic and time-varying impulses can be analyzed using the operator's transient and stationary properties. Furthermore, an unreported stochastic dynamic bifurcation for the biological oscillator is obtained by using the eigenvalues of the product of the Markov operators. PMID:21867230

  3. Telescope Time Allocation Tool

    NASA Astrophysics Data System (ADS)

    Alves, J.

    2005-03-01

    TaToo is ESO's new Time Allocation Tool. This software scheduler is a combination of a user-friendly graphical user interface and an intelligent constraint-programming engine fine-tuned to ESO's scheduling problem. TaToo is able to produce a high quality and reliable schedule taking into consideration all constraints of the recommended programs for all telescopes in about 15 minutes. This performance allows schedulers at ESO-VISAS to simulate and evaluate different scenarios, optimize the scheduling of engineering activities at the observatories, and in the end construct the most science efficient schedule possible.

  4. Allocations for HANDI 2000 business management system

    SciTech Connect

    Wilson, D.

    1998-08-24

    The Data Integration 2000 Project will result in an integrated and comprehensive set of functional applications containing core information necessary to support the Project Hanford Management Contract. It is based on the Commercial-Off-The-Shelf product solution with commercially proven business processes. The COTS product solution set, of PassPort and People Soft software, supports finance, supply and chemical management/Material Safety Data Sheet, human resources. Allocations at Fluor Daniel Hanford are burdens added to base costs using a predetermined rate.

  5. Computationally efficient control allocation

    NASA Technical Reports Server (NTRS)

    Durham, Wayne (Inventor)

    2001-01-01

    A computationally efficient method for calculating near-optimal solutions to the three-objective, linear control allocation problem is disclosed. The control allocation problem is that of distributing the effort of redundant control effectors to achieve some desired set of objectives. The problem is deemed linear if control effectiveness is affine with respect to the individual control effectors. The optimal solution is that which exploits the collective maximum capability of the effectors within their individual physical limits. Computational efficiency is measured by the number of floating-point operations required for solution. The method presented returned optimal solutions in more than 90% of the cases examined; non-optimal solutions returned by the method were typically much less than 1% different from optimal and the errors tended to become smaller than 0.01% as the number of controls was increased. The magnitude of the errors returned by the present method was much smaller than those that resulted from either pseudo inverse or cascaded generalized inverse solutions. The computational complexity of the method presented varied linearly with increasing numbers of controls; the number of required floating point operations increased from 5.5 i, to seven times faster than did the minimum-norm solution (the pseudoinverse), and at about the same rate as did the cascaded generalized inverse solution. The computational requirements of the method presented were much better than that of previously described facet-searching methods which increase in proportion to the square of the number of controls.

  6. Stochastic Convection Parameterizations

    NASA Technical Reports Server (NTRS)

    Teixeira, Joao; Reynolds, Carolyn; Suselj, Kay; Matheou, Georgios

    2012-01-01

    computational fluid dynamics, radiation, clouds, turbulence, convection, gravity waves, surface interaction, radiation interaction, cloud and aerosol microphysics, complexity (vegetation, biogeochemistry, radiation versus turbulence/convection stochastic approach, non-linearities, Monte Carlo, high resolutions, large-Eddy Simulations, cloud structure, plumes, saturation in tropics, forecasting, parameterizations, stochastic, radiation-clod interaction, hurricane forecasts

  7. A Stochastic Employment Problem

    ERIC Educational Resources Information Center

    Wu, Teng

    2013-01-01

    The Stochastic Employment Problem(SEP) is a variation of the Stochastic Assignment Problem which analyzes the scenario that one assigns balls into boxes. Balls arrive sequentially with each one having a binary vector X = (X[subscript 1], X[subscript 2],...,X[subscript n]) attached, with the interpretation being that if X[subscript i] = 1 the ball…

  8. Research on allocation efficiency of the daisy chain allocation algorithm

    NASA Astrophysics Data System (ADS)

    Shi, Jingping; Zhang, Weiguo

    2013-03-01

    With the improvement of the aircraft performance in reliability, maneuverability and survivability, the number of the control effectors increases a lot. How to distribute the three-axis moments into the control surfaces reasonably becomes an important problem. Daisy chain method is simple and easy to be carried out in the design of the allocation system. But it can not solve the allocation problem for entire attainable moment subset. For the lateral-directional allocation problem, the allocation efficiency of the daisy chain can be directly measured by the area of its subset of attainable moments. Because of the non-linear allocation characteristic, the subset of attainable moments of daisy-chain method is a complex non-convex polygon, and it is difficult to solve directly. By analyzing the two-dimensional allocation problems with a "micro-element" idea, a numerical calculation algorithm is proposed to compute the area of the non-convex polygon. In order to improve the allocation efficiency of the algorithm, a genetic algorithm with the allocation efficiency chosen as the fitness function is proposed to find the best pseudo-inverse matrix.

  9. Stochastic Processes in Electrochemistry.

    PubMed

    Singh, Pradyumna S; Lemay, Serge G

    2016-05-17

    Stochastic behavior becomes an increasingly dominant characteristic of electrochemical systems as we probe them on the smallest scales. Advances in the tools and techniques of nanoelectrochemistry dictate that stochastic phenomena will become more widely manifest in the future. In this Perspective, we outline the conceptual tools that are required to analyze and understand this behavior. We draw on examples from several specific electrochemical systems where important information is encoded in, and can be derived from, apparently random signals. This Perspective attempts to serve as an accessible introduction to understanding stochastic phenomena in electrochemical systems and outlines why they cannot be understood with conventional macroscopic descriptions. PMID:27120701

  10. 24 CFR 92.50 - Formula allocation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Formula allocation. 92.50 Section... Development HOME INVESTMENT PARTNERSHIPS PROGRAM Allocation Formula § 92.50 Formula allocation. (a) Jurisdictions eligible for a formula allocation. HUD will provide allocations of funds in amounts determined...

  11. Polarised black holes in AdS

    NASA Astrophysics Data System (ADS)

    Costa, Miguel S.; Greenspan, Lauren; Oliveira, Miguel; Penedones, João; Santos, Jorge E.

    2016-06-01

    We consider solutions in Einstein-Maxwell theory with a negative cosmological constant that asymptote to global AdS 4 with conformal boundary {S}2× {{{R}}}t. At the sphere at infinity we turn on a space-dependent electrostatic potential, which does not destroy the asymptotic AdS behaviour. For simplicity we focus on the case of a dipolar electrostatic potential. We find two new geometries: (i) an AdS soliton that includes the full backreaction of the electric field on the AdS geometry; (ii) a polarised neutral black hole that is deformed by the electric field, accumulating opposite charges in each hemisphere. For both geometries we study boundary data such as the charge density and the stress tensor. For the black hole we also study the horizon charge density and area, and further verify a Smarr formula. Then we consider this system at finite temperature and compute the Gibbs free energy for both AdS soliton and black hole phases. The corresponding phase diagram generalizes the Hawking-Page phase transition. The AdS soliton dominates the low temperature phase and the black hole the high temperature phase, with a critical temperature that decreases as the external electric field increases. Finally, we consider the simple case of a free charged scalar field on {S}2× {{{R}}}t with conformal coupling. For a field in the SU(N ) adjoint representation we compare the phase diagram with the above gravitational system.

  12. Quantum Stochastic Processes

    SciTech Connect

    Spring, William Joseph

    2009-04-13

    We consider quantum analogues of n-parameter stochastic processes, associated integrals and martingale properties extending classical results obtained in [1, 2, 3], and quantum results in [4, 5, 6, 7, 8, 9, 10].

  13. Dynamics of Double Stochastic Operators

    NASA Astrophysics Data System (ADS)

    Saburov, Mansoor

    2016-03-01

    A double stochastic operator is a generalization of a double stochastic matrix. In this paper, we study the dynamics of double stochastic operators. We give a criterion for a regularity of a double stochastic operator in terms of absences of its periodic points. We provide some examples to insure that, in general, a trajectory of a double stochastic operator may converge to any interior point of the simplex.

  14. Resource Balancing Control Allocation

    NASA Technical Reports Server (NTRS)

    Frost, Susan A.; Bodson, Marc

    2010-01-01

    Next generation aircraft with a large number of actuators will require advanced control allocation methods to compute the actuator commands needed to follow desired trajectories while respecting system constraints. Previously, algorithms were proposed to minimize the l1 or l2 norms of the tracking error and of the control effort. The paper discusses the alternative choice of using the l1 norm for minimization of the tracking error and a normalized l(infinity) norm, or sup norm, for minimization of the control effort. The algorithm computes the norm of the actuator deflections scaled by the actuator limits. Minimization of the control effort then translates into the minimization of the maximum actuator deflection as a percentage of its range of motion. The paper shows how the problem can be solved effectively by converting it into a linear program and solving it using a simplex algorithm. Properties of the algorithm are investigated through examples. In particular, the min-max criterion results in a type of resource balancing, where the resources are the control surfaces and the algorithm balances these resources to achieve the desired command. A study of the sensitivity of the algorithms to the data is presented, which shows that the normalized l(infinity) algorithm has the lowest sensitivity, although high sensitivities are observed whenever the limits of performance are reached.

  15. WHEN TO STORE ENERGY IN A STOCHASTIC ENVIRONMENT

    PubMed Central

    Fischer, Barbara; Dieckmann, Ulf; Taborsky, Barbara

    2012-01-01

    The ability to store energy enables organisms to deal with temporarily harsh and uncertain conditions. Empirical studies have demonstrated that organisms adapted to fluctuating energy availability plastically adjust their storage strategies. So far, however, theoretical studies have investigated general storage strategies only in constant or deterministically varying environments. In this study, we analyze how the ability to store energy influences optimal energy allocation to storage, reproduction, and maintenance in environments in which energy availability varies stochastically. We find that allocation to storage is evolutionarily optimal when environmental energy availability is intermediate and energy stores are not yet too full. In environments with low variability and low predictability of energy availability, it is not optimal to store energy. As environments become more variable or more predictable, energy allocation to storage is increasingly favored. By varying environmental variability, environmental predictability, and the cost of survival, we obtain a variety of different optimal life-history strategies, from highly iteroparous to semelparous, which differ significantly in their storage patterns. Our results demonstrate that in a stochastically varying environment simultaneous allocation to reproduction, maintenance, and storage can be optimal, which contrasts with previous findings obtained for deterministic environments. PMID:21108636

  16. Resource allocation using risk analysis

    SciTech Connect

    Bott, T. F.; Eisenhawer, S. W.

    2003-01-01

    Allocating limited resources among competing priorities is an important problem in management. In this paper we describe an approach to resource allocation using risk as a metric. We call this approach the Logic-Evolved Decision (LED) approach because we use logic-models to generate an exhaustive set of competing options and to describe the often highly complex model used for evaluating the risk reduction achieved by different resource allocations among these options. The risk evaluation then proceeds using probabilistic or linguistic input data.

  17. Constructing Lifshitz solutions from AdS

    NASA Astrophysics Data System (ADS)

    Cassani, Davide; Faedo, Anton F.

    2011-05-01

    Under general assumptions, we show that a gravitational theory in d + 1 dimensions admitting an AdS solution can be reduced to a d-dimensional theory containing a Lifshitz solution with dynamical exponent z = 2. Working in a d = 4, mathcal{N} = 2 supergravity setup, we prove that if the AdS background is mathcal{N} = 2 supersymmetric, then the Lifshitz geometry preserves 1/4 of the supercharges, and we construct the corresponding Killing spinors. We illustrate these results in examples from supersymmetric consistent truncations of type IIB supergravity, enhancing the class of known 4-dimensional Lifshitz solutions of string theory. As a byproduct, we find a new AdS4 × S 1 × T 1,1 solution of type IIB.

  18. Collaborative Resource Allocation

    NASA Technical Reports Server (NTRS)

    Wang, Yeou-Fang; Wax, Allan; Lam, Raymond; Baldwin, John; Borden, Chester

    2007-01-01

    Collaborative Resource Allocation Networking Environment (CRANE) Version 0.5 is a prototype created to prove the newest concept of using a distributed environment to schedule Deep Space Network (DSN) antenna times in a collaborative fashion. This program is for all space-flight and terrestrial science project users and DSN schedulers to perform scheduling activities and conflict resolution, both synchronously and asynchronously. Project schedulers can, for the first time, participate directly in scheduling their tracking times into the official DSN schedule, and negotiate directly with other projects in an integrated scheduling system. A master schedule covers long-range, mid-range, near-real-time, and real-time scheduling time frames all in one, rather than the current method of separate functions that are supported by different processes and tools. CRANE also provides private workspaces (both dynamic and static), data sharing, scenario management, user control, rapid messaging (based on Java Message Service), data/time synchronization, workflow management, notification (including emails), conflict checking, and a linkage to a schedule generation engine. The data structure with corresponding database design combines object trees with multiple associated mortal instances and relational database to provide unprecedented traceability and simplify the existing DSN XML schedule representation. These technologies are used to provide traceability, schedule negotiation, conflict resolution, and load forecasting from real-time operations to long-range loading analysis up to 20 years in the future. CRANE includes a database, a stored procedure layer, an agent-based middle tier, a Web service wrapper, a Windows Integrated Analysis Environment (IAE), a Java application, and a Web page interface.

  19. Uncertainty Representation in Stochastic Reservoir Optimization

    NASA Astrophysics Data System (ADS)

    Lamontagne, J. R.; Stedinger, J. R.; Shoemaker, C. A.; Tan, S. N.

    2014-12-01

    Water resources managers attempt to operate reservoir and hydropower systems to maximize system objectives, subject to a host of physical and policy constraints, and in light of uncertainty about future conditions. Optimization models are widely used to advise the decision making process. An important aspect of such models is how uncertainties related to future hydrologic and economic conditions are represented, and the extent to which different uncertainty representations affect the quality of recommended decisions. This study explores the consequences of different uncertainty representations in stochastic optimization models of hydropower systems by comparing simulated system performance using different stochastic optimization models. An important question is whether the added computational burden from greater uncertainty resolution (which can be prohibitive for operational models in many cases) actually improves model recommendations. This is particularly relevant as more complex, ensemble forecasts are incorporated into short- and mid-term planning models. Another important consideration is how watershed hydrology (both seasonal and episodic characteristics), system size, economic context, and the temporal resolution of the model influence how uncertainty should be represented. These topics are explored through several US examples including a sampling stochastic dynamic programming (SSDP) model of a small single-reservoir system on the Kennebec River in Maine, and a stochastic programming model of the large multi-reservoir Federal Columbia River system in the Pacific Northwest. These studies highlight the importance of flexible model frameworks which allow exploration of different representations of a system and of uncertainties before locking operational decision support system development into a specific representation.

  20. Smeared antibranes polarise in AdS

    NASA Astrophysics Data System (ADS)

    Gautason, Fridrik Freyr; Truijen, Brecht; Van Riet, Thomas

    2015-07-01

    In the recent literature it has been questioned whether the local backreaction of antibranes in flux throats can induce a perturbative brane-flux decay. Most evidence for this can be gathered for D6 branes and D p branes smeared over 6 - p compact directions, in line with the absence of finite temperature solutions for these cases. The solutions in the literature have flat worldvolume geometries and non-compact transversal spaces. In this paper we consider what happens when the worldvolume is AdS and the transversal space is compact. We show that in these circumstances brane polarisation smoothens out the flux singularity, which is an indication that brane-flux decay is prevented. This is consistent with the fact that the cosmological constant would be less negative after brane-flux decay. Our results extend recent results on AdS7 solutions from D6 branes to AdS p+1 solutions from D p branes. We show that supersymmetry of the AdS solutions depend on p non-trivially.

  1. Inverse Statistics and Asset Allocation Efficiency

    NASA Astrophysics Data System (ADS)

    Bolgorian, Meysam

    In this paper using inverse statistics analysis, the effect of investment horizon on the efficiency of portfolio selection is examined. Inverse statistics analysis is a general tool also known as probability distribution of exit time that is used for detecting the distribution of the time in which a stochastic process exits from a zone. This analysis was used in Refs. 1 and 2 for studying the financial returns time series. This distribution provides an optimal investment horizon which determines the most likely horizon for gaining a specific return. Using samples of stocks from Tehran Stock Exchange (TSE) as an emerging market and S&P 500 as a developed market, effect of optimal investment horizon in asset allocation is assessed. It is found that taking into account the optimal investment horizon in TSE leads to more efficiency for large size portfolios while for stocks selected from S&P 500, regardless of portfolio size, this strategy does not only not produce more efficient portfolios, but also longer investment horizons provides more efficiency.

  2. Stochastic modelling of intermittency.

    PubMed

    Stemler, Thomas; Werner, Johannes P; Benner, Hartmut; Just, Wolfram

    2010-01-13

    Recently, methods have been developed to model low-dimensional chaotic systems in terms of stochastic differential equations. We tested such methods in an electronic circuit experiment. We aimed to obtain reliable drift and diffusion coefficients even without a pronounced time-scale separation of the chaotic dynamics. By comparing the analytical solutions of the corresponding Fokker-Planck equation with experimental data, we show here that crisis-induced intermittency can be described in terms of a stochastic model which is dominated by state-space-dependent diffusion. Further on, we demonstrate and discuss some limits of these modelling approaches using numerical simulations. This enables us to state a criterion that can be used to decide whether a stochastic model will capture the essential features of a given time series. PMID:19948556

  3. 24 CFR 92.50 - Formula allocation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Formula allocation. 92.50 Section 92.50 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development HOME INVESTMENT PARTNERSHIPS PROGRAM Allocation Formula § 92.50 Formula allocation. (a) Jurisdictions eligible for a formula allocation. HUD...

  4. A stochastic model of eye lens growth.

    PubMed

    Šikić, Hrvoje; Shi, Yanrong; Lubura, Snježana; Bassnett, Steven

    2015-07-01

    The size and shape of the ocular lens must be controlled with precision if light is to be focused sharply on the retina. The lifelong growth of the lens depends on the production of cells in the anterior epithelium. At the lens equator, epithelial cells differentiate into fiber cells, which are added to the surface of the existing fiber cell mass, increasing its volume and area. We developed a stochastic model relating the rates of cell proliferation and death in various regions of the lens epithelium to deposition of fiber cells and radial lens growth. Epithelial population dynamics were modeled as a branching process with emigration and immigration between proliferative zones. Numerical simulations were in agreement with empirical measurements and demonstrated that, operating within the strict confines of lens geometry, a stochastic growth engine can produce the smooth and precise growth necessary for lens function. PMID:25816743

  5. Stochastic Feedforward Control Technique

    NASA Technical Reports Server (NTRS)

    Halyo, Nesim

    1990-01-01

    Class of commanded trajectories modeled as stochastic process. Advanced Transport Operating Systems (ATOPS) research and development program conducted by NASA Langley Research Center aimed at developing capabilities for increases in capacities of airports, safe and accurate flight in adverse weather conditions including shear, winds, avoidance of wake vortexes, and reduced consumption of fuel. Advances in techniques for design of modern controls and increased capabilities of digital flight computers coupled with accurate guidance information from Microwave Landing System (MLS). Stochastic feedforward control technique developed within context of ATOPS program.

  6. Stochastic Gauss equations

    NASA Astrophysics Data System (ADS)

    Pierret, Frédéric

    2016-02-01

    We derived the equations of Celestial Mechanics governing the variation of the orbital elements under a stochastic perturbation, thereby generalizing the classical Gauss equations. Explicit formulas are given for the semimajor axis, the eccentricity, the inclination, the longitude of the ascending node, the pericenter angle, and the mean anomaly, which are expressed in term of the angular momentum vector H per unit of mass and the energy E per unit of mass. Together, these formulas are called the stochastic Gauss equations, and they are illustrated numerically on an example from satellite dynamics.

  7. Stochastic Completeness of Graphs

    NASA Astrophysics Data System (ADS)

    Wojciechowski, Radoslaw K.

    2007-12-01

    In this thesis, we analyze the stochastic completeness of a heat kernel on graphs which is a function of three variables: a pair of vertices and a continuous time, for infinite, locally finite, connected graphs. For general graphs, a sufficient condition for stochastic completeness is given in terms of the maximum valence on spheres about a fixed vertex. That this result is optimal is shown by studying a particular family of trees. We also prove a lower bound on the bottom of the spectrum for the discrete Laplacian and use this lower bound to show that in certain cases the Laplacian has empty essential spectrum.

  8. Decentralized stochastic control

    NASA Technical Reports Server (NTRS)

    Speyer, J. L.

    1980-01-01

    Decentralized stochastic control is characterized by being decentralized in that the information to one controller is not the same as information to another controller. The system including the information has a stochastic or uncertain component. This complicates the development of decision rules which one determines under the assumption that the system is deterministic. The system is dynamic which means the present decisions affect future system responses and the information in the system. This circumstance presents a complex problem where tools like dynamic programming are no longer applicable. These difficulties are discussed from an intuitive viewpoint. Particular assumptions are introduced which allow a limited theory which produces mechanizable affine decision rules.

  9. STOCHASTIC COOLING FOR BUNCHED BEAMS.

    SciTech Connect

    BLASKIEWICZ, M.

    2005-05-16

    Problems associated with bunched beam stochastic cooling are reviewed. A longitudinal stochastic cooling system for RHIC is under construction and has been partially commissioned. The state of the system and future plans are discussed.

  10. Stochastic entrainment of a stochastic oscillator.

    PubMed

    Wang, Guanyu; Peskin, Charles S

    2015-11-01

    In this work, we consider a stochastic oscillator described by a discrete-state continuous-time Markov chain, in which the states are arranged in a circle, and there is a constant probability per unit time of jumping from one state to the next in a specified direction around the circle. At each of a sequence of equally spaced times, the oscillator has a specified probability of being reset to a particular state. The focus of this work is the entrainment of the oscillator by this periodic but stochastic stimulus. We consider a distinguished limit, in which (i) the number of states of the oscillator approaches infinity, as does the probability per unit time of jumping from one state to the next, so that the natural mean period of the oscillator remains constant, (ii) the resetting probability approaches zero, and (iii) the period of the resetting signal approaches a multiple, by a ratio of small integers, of the natural mean period of the oscillator. In this distinguished limit, we use analytic and numerical methods to study the extent to which entrainment occurs. PMID:26651734

  11. Hamiltonian mechanics of stochastic acceleration.

    PubMed

    Burby, J W; Zhmoginov, A I; Qin, H

    2013-11-01

    We show how to find the physical Langevin equation describing the trajectories of particles undergoing collisionless stochastic acceleration. These stochastic differential equations retain not only one-, but two-particle statistics, and inherit the Hamiltonian nature of the underlying microscopic equations. This opens the door to using stochastic variational integrators to perform simulations of stochastic interactions such as Fermi acceleration. We illustrate the theory by applying it to two example problems. PMID:24266476

  12. Optimal vaccination in a stochastic epidemic model of two non-interacting populations.

    PubMed

    Yuan, Edwin C; Alderson, David L; Stromberg, Sean; Carlson, Jean M

    2015-01-01

    Developing robust, quantitative methods to optimize resource allocations in response to epidemics has the potential to save lives and minimize health care costs. In this paper, we develop and apply a computationally efficient algorithm that enables us to calculate the complete probability distribution for the final epidemic size in a stochastic Susceptible-Infected-Recovered (SIR) model. Based on these results, we determine the optimal allocations of a limited quantity of vaccine between two non-interacting populations. We compare the stochastic solution to results obtained for the traditional, deterministic SIR model. For intermediate quantities of vaccine, the deterministic model is a poor estimate of the optimal strategy for the more realistic, stochastic case. PMID:25688857

  13. Optimal Vaccination in a Stochastic Epidemic Model of Two Non-Interacting Populations

    PubMed Central

    Yuan, Edwin C.; Alderson, David L.; Stromberg, Sean; Carlson, Jean M.

    2015-01-01

    Developing robust, quantitative methods to optimize resource allocations in response to epidemics has the potential to save lives and minimize health care costs. In this paper, we develop and apply a computationally efficient algorithm that enables us to calculate the complete probability distribution for the final epidemic size in a stochastic Susceptible-Infected-Recovered (SIR) model. Based on these results, we determine the optimal allocations of a limited quantity of vaccine between two non-interacting populations. We compare the stochastic solution to results obtained for the traditional, deterministic SIR model. For intermediate quantities of vaccine, the deterministic model is a poor estimate of the optimal strategy for the more realistic, stochastic case. PMID:25688857

  14. Stochastic Models of Human Growth.

    ERIC Educational Resources Information Center

    Goodrich, Robert L.

    Stochastic difference equations of the Box-Jenkins form provide an adequate family of models on which to base the stochastic theory of human growth processes, but conventional time series identification methods do not apply to available data sets. A method to identify structure and parameters of stochastic difference equation models of human…

  15. Task allocation in a distributed computing system

    NASA Technical Reports Server (NTRS)

    Seward, Walter D.

    1987-01-01

    A conceptual framework is examined for task allocation in distributed systems. Application and computing system parameters critical to task allocation decision processes are discussed. Task allocation techniques are addressed which focus on achieving a balance in the load distribution among the system's processors. Equalization of computing load among the processing elements is the goal. Examples of system performance are presented for specific applications. Both static and dynamic allocation of tasks are considered and system performance is evaluated using different task allocation methodologies.

  16. Collective credit allocation in science.

    PubMed

    Shen, Hua-Wei; Barabási, Albert-László

    2014-08-26

    Collaboration among researchers is an essential component of the modern scientific enterprise, playing a particularly important role in multidisciplinary research. However, we continue to wrestle with allocating credit to the coauthors of publications with multiple authors, because the relative contribution of each author is difficult to determine. At the same time, the scientific community runs an informal field-dependent credit allocation process that assigns credit in a collective fashion to each work. Here we develop a credit allocation algorithm that captures the coauthors' contribution to a publication as perceived by the scientific community, reproducing the informal collective credit allocation of science. We validate the method by identifying the authors of Nobel-winning papers that are credited for the discovery, independent of their positions in the author list. The method can also compare the relative impact of researchers working in the same field, even if they did not publish together. The ability to accurately measure the relative credit of researchers could affect many aspects of credit allocation in science, potentially impacting hiring, funding, and promotion decisions. PMID:25114238

  17. Collective credit allocation in science

    PubMed Central

    Shen, Hua-Wei; Barabási, Albert-László

    2014-01-01

    Collaboration among researchers is an essential component of the modern scientific enterprise, playing a particularly important role in multidisciplinary research. However, we continue to wrestle with allocating credit to the coauthors of publications with multiple authors, because the relative contribution of each author is difficult to determine. At the same time, the scientific community runs an informal field-dependent credit allocation process that assigns credit in a collective fashion to each work. Here we develop a credit allocation algorithm that captures the coauthors’ contribution to a publication as perceived by the scientific community, reproducing the informal collective credit allocation of science. We validate the method by identifying the authors of Nobel-winning papers that are credited for the discovery, independent of their positions in the author list. The method can also compare the relative impact of researchers working in the same field, even if they did not publish together. The ability to accurately measure the relative credit of researchers could affect many aspects of credit allocation in science, potentially impacting hiring, funding, and promotion decisions. PMID:25114238

  18. On the fair division of multiple stochastic pies to multiple agents within the Nash bargaining solution.

    PubMed

    Karmperis, Athanasios C; Aravossis, Konstantinos; Tatsiopoulos, Ilias P; Sotirchos, Anastasios

    2012-01-01

    The fair division of a surplus is one of the most widely examined problems. This paper focuses on bargaining problems with fixed disagreement payoffs where risk-neutral agents have reached an agreement that is the Nash-bargaining solution (NBS). We consider a stochastic environment, in which the overall return consists of multiple pies with uncertain sizes and we examine how these pies can be allocated with fairness among agents. Specifically, fairness is based on the Aristotle's maxim: "equals should be treated equally and unequals unequally, in proportion to the relevant inequality". In this context, fairness is achieved when all the individual stochastic surplus shares which are allocated to agents are distributed in proportion to the NBS. We introduce a novel algorithm, which can be used to compute the ratio of each pie that should be allocated to each agent, in order to ensure fairness within a symmetric or asymmetric NBS. PMID:23024752

  19. On the Fair Division of Multiple Stochastic Pies to Multiple Agents within the Nash Bargaining Solution

    PubMed Central

    Karmperis, Athanasios C.; Aravossis, Konstantinos; Tatsiopoulos, Ilias P.; Sotirchos, Anastasios

    2012-01-01

    The fair division of a surplus is one of the most widely examined problems. This paper focuses on bargaining problems with fixed disagreement payoffs where risk-neutral agents have reached an agreement that is the Nash-bargaining solution (NBS). We consider a stochastic environment, in which the overall return consists of multiple pies with uncertain sizes and we examine how these pies can be allocated with fairness among agents. Specifically, fairness is based on the Aristotle’s maxim: “equals should be treated equally and unequals unequally, in proportion to the relevant inequality”. In this context, fairness is achieved when all the individual stochastic surplus shares which are allocated to agents are distributed in proportion to the NBS. We introduce a novel algorithm, which can be used to compute the ratio of each pie that should be allocated to each agent, in order to ensure fairness within a symmetric or asymmetric NBS. PMID:23024752

  20. Focus on stochastic thermodynamics

    NASA Astrophysics Data System (ADS)

    Van den Broeck, Christian; Sasa, Shin-ichi; Seifert, Udo

    2016-02-01

    We introduce the thirty papers collected in this ‘focus on’ issue. The contributions explore conceptual issues within and around stochastic thermodynamics, use this framework for the theoretical modeling and experimental investigation of specific systems, and provide further perspectives on and for this active field.

  1. Task allocation among multiple intelligent robots

    NASA Technical Reports Server (NTRS)

    Gasser, L.; Bekey, G.

    1987-01-01

    Researchers describe the design of a decentralized mechanism for allocating assembly tasks in a multiple robot assembly workstation. Currently, the approach focuses on distributed allocation to explore its feasibility and its potential for adaptability to changing circumstances, rather than for optimizing throughput. Individual greedy robots make their own local allocation decisions using both dynamic allocation policies which propagate through a network of allocation goals, and local static and dynamic constraints describing which robots are elibible for which assembly tasks. Global coherence is achieved by proper weighting of allocation pressures propagating through the assembly plan. Deadlock avoidance and synchronization is achieved using periodic reassessments of local allocation decisions, ageing of allocation goals, and short-term allocation locks on goals.

  2. Solvable stochastic dealer models for financial markets

    NASA Astrophysics Data System (ADS)

    Yamada, Kenta; Takayasu, Hideki; Ito, Takatoshi; Takayasu, Misako

    2009-05-01

    We introduce solvable stochastic dealer models, which can reproduce basic empirical laws of financial markets such as the power law of price change. Starting from the simplest model that is almost equivalent to a Poisson random noise generator, the model becomes fairly realistic by adding only two effects: the self-modulation of transaction intervals and a forecasting tendency, which uses a moving average of the latest market price changes. Based on the present microscopic model of markets, we find a quantitative relation with market potential forces, which have recently been discovered in the study of market price modeling based on random walks.

  3. Regulating nutrient allocation in plants

    DOEpatents

    Udvardi, Michael; Yang, Jiading; Worley, Eric

    2014-12-09

    The invention provides coding and promoter sequences for a VS-1 and AP-2 gene, which affects the developmental process of senescence in plants. Vectors, transgenic plants, seeds, and host cells comprising heterologous VS-1 and AP-2 genes are also provided. Additionally provided are methods of altering nutrient allocation and composition in a plant using the VS-1 and AP-2 genes.

  4. Operational risk economic capital allocation

    NASA Astrophysics Data System (ADS)

    Nikonov, Oleg I.; Vlasov, Vladimir E.; Medvedeva, Marina A.

    2013-10-01

    In the paper we describe a model of operational risk of economic capital estimation and allocation based on Loss Distribution Approach (LDA). Bank's total losses are modeled through Monte-Carlo simulations of its business units' losses. It allows to fairly distributing the corresponding capital between business units in order to assess and manage their risk adjusted performance.

  5. The Discipline of Asset Allocation.

    ERIC Educational Resources Information Center

    Petzel, Todd E.

    2000-01-01

    Discussion of asset allocation for college/university endowment funds focuses on three levels of risk: (1) the absolute risk of the portfolio (usually leading to asset diversification); (2) the benchmark risk (usually comparison with peer institutions; and (3) personal career risk (which may incline managers toward maximizing short-term returns,…

  6. Administrators' Decisions about Resource Allocation

    ERIC Educational Resources Information Center

    Knight, William E.; Folkins, John W.; Hakel, Milton D.; Kennell, Richard P.

    2011-01-01

    Do academic administrators make decisions about resource allocation differently depending on the discipline receiving the funding? Does an administrator's academic identity influence these decisions? This study explored those questions with a sample of 1,690 academic administrators at doctoral-research universities. Participants used fictional…

  7. Administrators' Decisions about Resource Allocation

    ERIC Educational Resources Information Center

    Knight, William E.; Folkins, John W.; Hakel, Milton D.; Kennell, Richard P.

    2011-01-01

    Do academic administrators make decisions about resource allocation differently depending on the discipline receiving the funding? Does an administrator's academic identity influence these decisions? This study explored those questions with a sample of 1,690 academic administrators at doctoral-research universities. Participants used fictional

  8. STOCHASTIC COOLING FOR RHIC.

    SciTech Connect

    BLASKIEWICZ,M.BRENNAN,J.M.CAMERON,P.WEI,J.

    2003-05-12

    Emittance growth due to Intra-Beam Scattering significantly reduces the heavy ion luminosity lifetime in RHIC. Stochastic cooling of the stored beam could improve things considerably by counteracting IBS and preventing particles from escaping the rf bucket [1]. High frequency bunched-beam stochastic cooling is especially challenging but observations of Schottky signals in the 4-8 GHz band indicate that conditions are favorable in RHIC [2]. We report here on measurements of the longitudinal beam transfer function carried out with a pickup kicker pair on loan from FNAL TEVATRON. Results imply that for ions a coasting beam description is applicable and we outline some general features of a viable momentum cooling system for RHIC.

  9. STOCHASTIC COOLING POWER REQUIREMENTS.

    SciTech Connect

    WEI,J.BLASKIEWICZ,M.BRENNAN,M.

    2004-07-05

    A practical obstacle for stochastic cooling in high-energy colliders like RHIC is the large amount of power needed for the cooling system. Based on the coasting-beam Fokker-Planck (F-P) equation, we analytically derived the optimum cooling rate and cooling power for a beam of uniform distribution and a cooling system of linear gain function. The results indicate that the usual back-of-envelope formula over-estimated the cooling power by a factor of the mixing factor M. On the other hand, the scaling laws derived from the coasting-beam Fokker-Planck approach agree with those derived from the bunched-beam Fokker-Planck approach if the peak beam intensity is used as the effective coasting-beam intensity. A longitudinal stochastic cooling system of 4-8 GHz bandwidth in RHIC can effectively counteract intrabeam scattering, preventing the beam from escaping the RF bucket becoming debunched around the ring.

  10. Entropy of stochastic flows

    SciTech Connect

    Dorogovtsev, Andrei A

    2010-06-29

    For sets in a Hilbert space the concept of quadratic entropy is introduced. It is shown that this entropy is finite for the range of a stochastic flow of Brownian particles on R. This implies, in particular, the fact that the total time of the free travel in the Arratia flow of all particles that started from a bounded interval is finite. Bibliography: 10 titles.

  11. Probing crunching AdS cosmologies

    NASA Astrophysics Data System (ADS)

    Kumar, S. Prem; Vaganov, Vladislav

    2016-02-01

    Holographic gravity duals of deformations of CFTs formulated on de Sitter spacetime contain FRW geometries behind a horizon, with cosmological big crunch singularities. Using a specific analytically tractable solution within a particular single scalar truncation of {N}=8 supergravity on AdS4, we first probe such crunching cosmologies with spacelike radial geodesics that compute spatially antipodal correlators of large dimension boundary operators. At late times, the geodesics lie on the FRW slice of maximal expansion behind the horizon. The late time two-point functions factorise, and when transformed to the Einstein static universe, they exhibit a temporal non-analyticity determined by the maximal value of the scale factor ã max. Radial geodesics connecting antipodal points necessarily have de Sitter energy Ɛ ≲ ã max, while geodesics with Ɛ > ã max terminate at the crunch, the two categories of geodesics being separated by the maximal expansion slice. The spacelike crunch singularity is curved "outward" in the Penrose diagram for the deformed AdS backgrounds, and thus geodesic limits of the antipodal correlators do not directly probe the crunch. Beyond the geodesic limit, we point out that the scalar wave equation, analytically continued into the FRW patch, has a potential which is singular at the crunch along with complex WKB turning points in the vicinity of the FRW crunch. We then argue that the frequency space Green's function has a branch point determined by ã max which corresponds to the lowest quasinormal frequency.

  12. Quantum Spontaneous Stochasticity

    NASA Astrophysics Data System (ADS)

    Drivas, Theodore; Eyink, Gregory

    Classical Newtonian dynamics is expected to be deterministic, but recent fluid turbulence theory predicts that a particle advected at high Reynolds-numbers by ''nearly rough'' flows moves nondeterministically. Small stochastic perturbations to the flow velocity or to the initial data lead to persistent randomness, even in the limit where the perturbations vanish! Such ``spontaneous stochasticity'' has profound consequences for astrophysics, geophysics, and our daily lives. We show that a similar effect occurs with a quantum particle in a ''nearly rough'' force, for the semi-classical (large-mass) limit, where spreading of the wave-packet is usually expected to be negligible and dynamics to be deterministic Newtonian. Instead, there are non-zero probabilities to observe multiple, non-unique solutions of the classical equations. Although the quantum wave-function remains split, rapid phase oscillations prevent any coherent superposition of the branches. Classical spontaneous stochasticity has not yet been seen in controlled laboratory experiments of fluid turbulence, but the corresponding quantum effects may be observable by current techniques. We suggest possible experiments with neutral atomic-molecular systems in repulsive electric dipole potentials.

  13. Dynamic versus static allocation policies in multipurpose multireservoir systems

    NASA Astrophysics Data System (ADS)

    Tilmant, A.; Goor, Q.; Pinte, D.; van der Zaag, P.

    2007-12-01

    As the competition for water is likely to increase in the near future due to socioeconomic development and population growth, water resources managers will face hard choices when allocating water between competing users. Because water is a vital resource used in multiple sectors, including the environment, the allocation is inherently a political and social process, which is likely to become increasingly scrutinized as the competition grows between the different sectors. Since markets are usually absent or ineffective, the allocation of water between competing demands is achieved administratively taking into account key objectives such as economic efficiency, equity and maintaining the ecological integrity. When crop irrigation is involved, water is usually allocated by a system of annual rights to use a fixed, static, volume of water. In a fully-allocated basin, moving from a static to a dynamic allocation process, whereby the policies are regularly updated according to the hydrologic status of the river basin, is the first step towards the development of river basin management strategies that increase the productivity of water. More specifically, in a multipurpose multireservoir system, continuously adjusting release and withdrawal decisions based on the latest hydrologic information will increase the benefits derived from the system. However, the extent to which such an adjustment can be achieved results from complex spatial and temporal interactions between the physical characteristics of the water resources system (storage, natural flows), the economic and social consequences of rationing and the impacts on natural ecosystems. The complexity of the decision-making process, which requires the continuous evaluation of numerous trade-offs, calls for the use of integrated hydrologic-economic models. This paper compares static and dynamic management approaches for a cascade of hydropower-irrigation reservoirs using stochastic dual dynamic programming (SDDP) formulations. As its name indicates, SDDP is an extension of SDP that removes the curse of dimensionality found in discrete SDP and can therefore be used to analyze large-scale water resources systems. For the static approach, the multiobjective (irrigation-hydropower) optimization problem is solved using the constraint method, i.e. net benefits from hydropower generation are maximized and irrigation water withdrawals are additional constraints. In the dynamic approach, the SDDP model seeks to maximize the net benefits of both hydropower and irrigation crop production. A cascade of 8 reservoirs in the Turkish and Syrian parts of the Euphrates river basin is used as a case study.

  14. On the stochastic treatment of fast chemical reactions.

    PubMed

    Zaider, M; Brenner, D J

    1984-11-01

    A Monte Carlo code was developed to stimulate stochastically the fast reactions of radiolysis products in water. The results of these calculations show that treatments based on deterministic kinetic rate equations do not reproduce correctly the evolution in time of the number of species. Ad hoc initial distributions of species in spurs, of the type used in deterministic approaches, are compared with more realistic distributions obtained from Monte Carlo-generated particle tracks. The effects of using either type of distribution, stochastically or deterministically, are discussed. PMID:6494437

  15. Models for interrupted monitoring of a stochastic process

    NASA Technical Reports Server (NTRS)

    Palmer, E.

    1977-01-01

    As computers are added to the cockpit, the pilot's job is changing from of manually flying the aircraft, to one of supervising computers which are doing navigation, guidance and energy management calculations as well as automatically flying the aircraft. In this supervisorial role the pilot must divide his attention between monitoring the aircraft's performance and giving commands to the computer. Normative strategies are developed for tasks where the pilot must interrupt his monitoring of a stochastic process in order to attend to other duties. Results are given as to how characteristics of the stochastic process and the other tasks affect the optimal strategies.

  16. On impulsive integrated pest management models with stochastic effects

    PubMed Central

    Akman, Olcay; Comar, Timothy D.; Hrozencik, Daniel

    2015-01-01

    We extend existing impulsive differential equation models for integrated pest management (IPM) by including stage structure for both predator and prey as well as by adding stochastic elements in the birth rate of the prey. Based on our model, we propose an approach that incorporates various competing stochastic components. This approach enables us to select a model with optimally determined weights for maximum accuracy and precision in parameter estimation. This is significant in the case of IPM because the proposed model accommodates varying unknown environmental and climatic conditions, which affect the resources needed for pest eradication. PMID:25954144

  17. 50 CFR 660.323 - Pacific whiting allocations, allocation attainment, and inseason allocation reapportionment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., by e-mail, internet (www.nwr.noaa.gov/Groundfish-Halibut/Groundfish-Fishery-Management/Whiting... CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED... whiting allocations are provided in § 660.385(e). (2) The non-tribal commercial harvest guideline...

  18. 45 CFR 1355.57 - Cost allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MAINTENANCE PAYMENTS, ADOPTION ASSISTANCE, AND CHILD AND FAMILY SERVICES GENERAL § 1355.57 Cost allocation. (a... maintenance payments or adoption assistance payments may be made under the State plan. (b) Cost allocation...

  19. Strategic planning for disaster recovery with stochastic last mile distribution

    SciTech Connect

    Bent, Russell Whitford; Van Hentenryck, Pascal; Coffrin, Carleton

    2010-01-01

    This paper considers the single commodity allocation problem (SCAP) for disaster recovery, a fundamental problem faced by all populated areas. SCAPs are complex stochastic optimization problems that combine resource allocation, warehouse routing, and parallel fleet routing. Moreover, these problems must be solved under tight runtime constraints to be practical in real-world disaster situations. This paper formalizes the specification of SCAPs and introduces a novel multi-stage hybrid-optimization algorithm that utilizes the strengths of mixed integer programming, constraint programming, and large neighborhood search. The algorithm was validated on hurricane disaster scenarios generated by Los Alamos National Laboratory using state-of-the-art disaster simulation tools and is deployed to aid federal organizations in the US.

  20. A retrodictive stochastic simulation algorithm

    SciTech Connect

    Vaughan, T.G. Drummond, P.D.; Drummond, A.J.

    2010-05-20

    In this paper we describe a simple method for inferring the initial states of systems evolving stochastically according to master equations, given knowledge of the final states. This is achieved through the use of a retrodictive stochastic simulation algorithm which complements the usual predictive stochastic simulation approach. We demonstrate the utility of this new algorithm by applying it to example problems, including the derivation of likely ancestral states of a gene sequence given a Markovian model of genetic mutation.

  1. 24 CFR 574.130 - Formula allocations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Formula allocations. 574.130... URBAN DEVELOPMENT COMMUNITY FACILITIES HOUSING OPPORTUNITIES FOR PERSONS WITH AIDS Formula Entitlements § 574.130 Formula allocations. (a) Data sources. HUD will allocate funds based on the number of cases...

  2. 15 CFR 923.110 - Allocation formula.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Allocation formula. 923.110 Section... Grants § 923.110 Allocation formula. (a) As required by subsection 306(a), the Secretary may make grants...) Allocation formula factors and weighting. Each State eligible to receive a financial assistance award...

  3. Teachers' Embodied Allocations in Instructional Interaction

    ERIC Educational Resources Information Center

    Kääntä, Leila

    2012-01-01

    This paper describes how teachers employ gaze, head nods and pointing gestures in allocating response turns to students in whole-class instructional interaction. Specifically, it focuses on examining teachers' embodied allocations--that is, turn-allocations produced (mostly) by embodied means--and the sequential positions in which they are…

  4. 45 CFR 98.55 - Cost allocation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 1 2014-10-01 2014-10-01 false Cost allocation. 98.55 Section 98.55 Public... of Child Care and Development Funds § 98.55 Cost allocation. (a) The Lead Agency and subgrantees shall keep on file cost allocation plans or indirect cost agreements, as appropriate, that have...

  5. 45 CFR 1355.57 - Cost allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Cost allocation. 1355.57 Section 1355.57 Public... MAINTENANCE PAYMENTS, ADOPTION ASSISTANCE, AND CHILD AND FAMILY SERVICES GENERAL § 1355.57 Cost allocation. (a... maintenance payments or adoption assistance payments may be made under the State plan. (b) Cost allocation...

  6. 45 CFR 98.55 - Cost allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 1 2011-10-01 2011-10-01 false Cost allocation. 98.55 Section 98.55 Public... of Child Care and Development Funds § 98.55 Cost allocation. (a) The Lead Agency and subgrantees shall keep on file cost allocation plans or indirect cost agreements, as appropriate, that have...

  7. 23 CFR 1240.15 - Allocations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Allocations. 1240.15 Section 1240.15 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES SAFETY INCENTIVE GRANTS FOR USE OF SEAT BELTS-ALLOCATIONS BASED ON SEAT BELT USE RATES Determination of Allocations § 1240.15...

  8. 10 CFR 455.31 - Allocation formulas.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Allocation formulas. 455.31 Section 455.31 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION GRANT PROGRAMS FOR SCHOOLS AND HOSPITALS AND BUILDINGS OWNED BY UNITS OF LOCAL GOVERNMENT AND PUBLIC CARE INSTITUTIONS Allocation of Appropriations Among the States § 455.31 Allocation formulas. (a)...

  9. Dynamic Resource Allocation in Disaster Response: Tradeoffs in Wildfire Suppression

    PubMed Central

    Petrovic, Nada; Alderson, David L.; Carlson, Jean M.

    2012-01-01

    Challenges associated with the allocation of limited resources to mitigate the impact of natural disasters inspire fundamentally new theoretical questions for dynamic decision making in coupled human and natural systems. Wildfires are one of several types of disaster phenomena, including oil spills and disease epidemics, where (1) the disaster evolves on the same timescale as the response effort, and (2) delays in response can lead to increased disaster severity and thus greater demand for resources. We introduce a minimal stochastic process to represent wildfire progression that nonetheless accurately captures the heavy tailed statistical distribution of fire sizes observed in nature. We then couple this model for fire spread to a series of response models that isolate fundamental tradeoffs both in the strength and timing of response and also in division of limited resources across multiple competing suppression efforts. Using this framework, we compute optimal strategies for decision making scenarios that arise in fire response policy. PMID:22514605

  10. 75 FR 18016 - Notice of Allocation Availability (NOAA) Inviting Applications for the CY 2010 Allocation Round...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-08

    ... Community Development Financial Institutions Fund Notice of Allocation Availability (NOAA) Inviting Applications for the CY 2010 Allocation Round of the New Markets Tax Credit Program Funding Opportunity Title: Notice of Allocation Availability (NOAA) Inviting Applications for the CY 2010 Allocation Round of...

  11. Minority Transportation Expenditure Allocation Model

    Energy Science and Technology Software Center (ESTSC)

    1993-04-12

    MITRAM (Minority TRansportation expenditure Allocation Model) can project various transportation related attributes of minority (Black and Hispanic) and majority (white) populations. The model projects vehicle ownership, vehicle miles of travel, workers, new car and on-road fleet fuel economy, amount and share of household income spent on gasoline, and household expenditures on public transportation and taxis. MITRAM predicts reactions to sustained fuel price changes for up to 10 years after the change.

  12. Allocating Variability and Reserve Requirements (Presentation)

    SciTech Connect

    Kirby, B.; King, J.; Milligan, M.

    2011-10-01

    This presentation describes how you could conceivably allocate variability and reserve requirements, including how to allocate aggregation benefits. Conclusions of this presentation are: (1) Aggregation provides benefits because individual requirements are not 100% correlated; (2) Method needed to allocate reduced requirement among participants; (3) Differences between allocation results are subtle - (a) Not immediately obvious which method is 'better'; (b) Many are numerically 'correct', they sum to the physical requirement; (c) Many are not 'fair', Results depend on sub-aggregation and/or the order individuals are included; and (4) Vector allocation method is simple and fair.

  13. Stochastic thermodynamics of resetting

    NASA Astrophysics Data System (ADS)

    Fuchs, Jaco; Goldt, Sebastian; Seifert, Udo

    2016-03-01

    Stochastic dynamics with random resetting leads to a non-equilibrium steady state. Here, we consider the thermodynamics of resetting by deriving the first and second law for resetting processes far from equilibrium. We identify the contributions to the entropy production of the system which arise due to resetting and show that they correspond to the rate with which information is either erased or created. Using Landauer's principle, we derive a bound on the amount of work that is required to maintain a resetting process. We discuss different regimes of resetting, including a Maxwell demon scenario where heat is extracted from a bath at constant temperature.

  14. Stochastic ontogenetic growth model

    NASA Astrophysics Data System (ADS)

    West, B. J.; West, D.

    2012-02-01

    An ontogenetic growth model (OGM) for a thermodynamically closed system is generalized to satisfy both the first and second law of thermodynamics. The hypothesized stochastic ontogenetic growth model (SOGM) is shown to entail the interspecies allometry relation by explicitly averaging the basal metabolic rate and the total body mass over the steady-state probability density for the total body mass (TBM). This is the first derivation of the interspecies metabolic allometric relation from a dynamical model and the asymptotic steady-state distribution of the TBM is fit to data and shown to be inverse power law.

  15. In search for a possible statistical basis of Stochastic Resonance

    NASA Astrophysics Data System (ADS)

    Bezrukov, Sergey M.; Vodyanoy, Igor

    2000-03-01

    Stochastic Resonance (SR) is a phenomenon of enhancing the information content at the system output by adding noise to the input signal. Originally, SR was shown in dynamical systems ranging from glaciers to superconducting junctions. Later it was found to occur in non-dynamical systems with and without thresholds. Now a growing number of publications report SR practically everywhere: in meteorology, sociology, finance, psycho-physics, electrophysiology, chemistry, etc. We seek a general statistical mechanism which would capture and, thus, explain the essence of SR independently of the system where it is found. Though, at present, this problem is far from solved, we think that the doubly-stochastic Poisson process approach described here represents a significant step toward such a generalization. Using this approach, we show that, in contrast to the current point of view, an activation barrier is not a necessary prerequisite of a Stochastic Resonator.

  16. Stochastic Quantum Gas Dynamics

    NASA Astrophysics Data System (ADS)

    Proukakis, Nick P.; Cockburn, Stuart P.

    2010-03-01

    We study the dynamics of weakly-interacting finite temperature Bose gases via the Stochastic Gross-Pitaevskii equation (SGPE). As a first step, we demonstrate [jointly with A. Negretti (Ulm, Germany) and C. Henkel (Potsdam, Germany)] that the SGPE provides a significantly better method for generating an equilibrium state than the number-conserving Bogoliubov method (except for low temperatures and small atom numbers). We then study [jointly with H. Nistazakis and D.J. Frantzeskakis (University of Athens, Greece), P.G.Kevrekidis (University of Massachusetts) and T.P. Horikis (University of Ioannina, Greece)] the dynamics of dark solitons in elongated finite temperature condensates. We demonstrate numerical shot-to-shot variations in soliton trajectories (S.P. Cockburn et al., arXiv:0909.1660.), finding individual long-lived trajectories as in experiments. In our simulations, these variations arise from fluctuations in the phase and density of the underlying medium. We provide a detailed statistical analysis, proposing regimes for the controlled experimental demonstration of this effect; we also discuss the extent to which simpler models can be used to mimic the features of ensemble-averaged stochastic trajectories.

  17. Stochastic power flow modeling

    SciTech Connect

    Not Available

    1980-06-01

    The stochastic nature of customer demand and equipment failure on large interconnected electric power networks has produced a keen interest in the accurate modeling and analysis of the effects of probabilistic behavior on steady state power system operation. The principle avenue of approach has been to obtain a solution to the steady state network flow equations which adhere both to Kirchhoff's Laws and probabilistic laws, using either combinatorial or functional approximation techniques. Clearly the need of the present is to develop sound techniques for producing meaningful data to serve as input. This research has addressed this end and serves to bridge the gap between electric demand modeling, equipment failure analysis, etc., and the area of algorithm development. Therefore, the scope of this work lies squarely on developing an efficient means of producing sensible input information in the form of probability distributions for the many types of solution algorithms that have been developed. Two major areas of development are described in detail: a decomposition of stochastic processes which gives hope of stationarity, ergodicity, and perhaps even normality; and a powerful surrogate probability approach using proportions of time which allows the calculation of joint events from one dimensional probability spaces.

  18. Stochastic blind motion deblurring.

    PubMed

    Xiao, Lei; Gregson, James; Heide, Felix; Heidrich, Wolfgang

    2015-10-01

    Blind motion deblurring from a single image is a highly under-constrained problem with many degenerate solutions. A good approximation of the intrinsic image can, therefore, only be obtained with the help of prior information in the form of (often nonconvex) regularization terms for both the intrinsic image and the kernel. While the best choice of image priors is still a topic of ongoing investigation, this research is made more complicated by the fact that historically each new prior requires the development of a custom optimization method. In this paper, we develop a stochastic optimization method for blind deconvolution. Since this stochastic solver does not require the explicit computation of the gradient of the objective function and uses only efficient local evaluation of the objective, new priors can be implemented and tested very quickly. We demonstrate that this framework, in combination with different image priors produces results with Peak Signal-to-Noise Ratio (PSNR) values that match or exceed the results obtained by much more complex state-of-the-art blind motion deblurring algorithms. PMID:25974941

  19. On the efficacy of stochastic collocation, stochastic Galerkin, and stochastic reduced order models for solving stochastic problems

    DOE PAGESBeta

    Richard V. Field, Jr.; Emery, John M.; Grigoriu, Mircea Dan

    2015-05-19

    The stochastic collocation (SC) and stochastic Galerkin (SG) methods are two well-established and successful approaches for solving general stochastic problems. A recently developed method based on stochastic reduced order models (SROMs) can also be used. Herein we provide a comparison of the three methods for some numerical examples; our evaluation only holds for the examples considered in the paper. The purpose of the comparisons is not to criticize the SC or SG methods, which have proven very useful for a broad range of applications, nor is it to provide overall ratings of these methods as compared to the SROM method.more » Furthermore, our objectives are to present the SROM method as an alternative approach to solving stochastic problems and provide information on the computational effort required by the implementation of each method, while simultaneously assessing their performance for a collection of specific problems.« less

  20. On the efficacy of stochastic collocation, stochastic Galerkin, and stochastic reduced order models for solving stochastic problems

    SciTech Connect

    Richard V. Field, Jr.; Emery, John M.; Grigoriu, Mircea Dan

    2015-05-19

    The stochastic collocation (SC) and stochastic Galerkin (SG) methods are two well-established and successful approaches for solving general stochastic problems. A recently developed method based on stochastic reduced order models (SROMs) can also be used. Herein we provide a comparison of the three methods for some numerical examples; our evaluation only holds for the examples considered in the paper. The purpose of the comparisons is not to criticize the SC or SG methods, which have proven very useful for a broad range of applications, nor is it to provide overall ratings of these methods as compared to the SROM method. Furthermore, our objectives are to present the SROM method as an alternative approach to solving stochastic problems and provide information on the computational effort required by the implementation of each method, while simultaneously assessing their performance for a collection of specific problems.

  1. Variance decomposition in stochastic simulators

    NASA Astrophysics Data System (ADS)

    Le Maître, O. P.; Knio, O. M.; Moraes, A.

    2015-06-01

    This work aims at the development of a mathematical and computational approach that enables quantification of the inherent sources of stochasticity and of the corresponding sensitivities in stochastic simulations of chemical reaction networks. The approach is based on reformulating the system dynamics as being generated by independent standardized Poisson processes. This reformulation affords a straightforward identification of individual realizations for the stochastic dynamics of each reaction channel, and consequently a quantitative characterization of the inherent sources of stochasticity in the system. By relying on the Sobol-Hoeffding decomposition, the reformulation enables us to perform an orthogonal decomposition of the solution variance. Thus, by judiciously exploiting the inherent stochasticity of the system, one is able to quantify the variance-based sensitivities associated with individual reaction channels, as well as the importance of channel interactions. Implementation of the algorithms is illustrated in light of simulations of simplified systems, including the birth-death, Schlögl, and Michaelis-Menten models.

  2. Switching of bound vector solitons for the coupled nonlinear Schroedinger equations with nonhomogenously stochastic perturbations

    SciTech Connect

    Sun Zhiyuan; Yu Xin; Liu Ying; Gao Yitian

    2012-12-15

    We investigate the dynamics of the bound vector solitons (BVSs) for the coupled nonlinear Schroedinger equations with the nonhomogenously stochastic perturbations added on their dispersion terms. Soliton switching (besides soliton breakup) can be observed between the two components of the BVSs. Rate of the maximum switched energy (absolute values) within the fixed propagation distance (about 10 periods of the BVSs) enhances in the sense of statistics when the amplitudes of stochastic perturbations increase. Additionally, it is revealed that the BVSs with enhanced coherence are more robust against the perturbations with nonhomogenous stochasticity. Diagram describing the approximate borders of the splitting and non-splitting areas is also given. Our results might be helpful in dynamics of the BVSs with stochastic noises in nonlinear optical fibers or with stochastic quantum fluctuations in Bose-Einstein condensates.

  3. Interactive visualization for resource allocation

    NASA Astrophysics Data System (ADS)

    Melissargos, George; Pu, Pearl

    1997-04-01

    Based on our experience in the design and construction of interactive resource reallocation systems, we argue about the advisability of interactive visualization as a means to increase the effectiveness of an intelligent system and we present a generic framework for solving rescheduling problems. A presentation of a flight rescheduling systems we have built, serves as the main implementation example of our proposed paradigm. We explain the specific visualization methods employed in the system and how visualization, coupled with artificial intelligence techniques, can aid in the difficult task of resource allocation.

  4. ADS pilot program Plan

    NASA Technical Reports Server (NTRS)

    Clauson, J.; Heuser, J.

    1981-01-01

    The Applications Data Service (ADS) is a system based on an electronic data communications network which will permit scientists to share the data stored in data bases at universities and at government and private installations. It is designed to allow users to readily locate and access high quality, timely data from multiple sources. The ADS Pilot program objectives and the current plans for accomplishing those objectives are described.

  5. Stochastic proximity embedding.

    PubMed

    Agrafiotis, Dimitris K

    2003-07-30

    We introduce stochastic proximity embedding (SPE), a novel self-organizing algorithm for producing meaningful underlying dimensions from proximity data. SPE attempts to generate low-dimensional Euclidean embeddings that best preserve the similarities between a set of related observations. The method starts with an initial configuration, and iteratively refines it by repeatedly selecting pairs of objects at random, and adjusting their coordinates so that their distances on the map match more closely their respective proximities. The magnitude of these adjustments is controlled by a learning rate parameter, which decreases during the course of the simulation to avoid oscillatory behavior. Unlike classical multidimensional scaling (MDS) and nonlinear mapping (NLM), SPE scales linearly with respect to sample size, and can be applied to very large data sets that are intractable by conventional embedding procedures. The method is programmatically simple, robust, and convergent, and can be applied to a wide range of scientific problems involving exploratory data analysis and visualization. PMID:12820129

  6. Stochastic reconstruction of sandstones

    PubMed

    Manwart; Torquato; Hilfer

    2000-07-01

    A simulated annealing algorithm is employed to generate a stochastic model for a Berea sandstone and a Fontainebleau sandstone, with each a prescribed two-point probability function, lineal-path function, and "pore size" distribution function, respectively. We find that the temperature decrease of the annealing has to be rather quick to yield isotropic and percolating configurations. A comparison of simple morphological quantities indicates good agreement between the reconstructions and the original sandstones. Also, the mean survival time of a random walker in the pore space is reproduced with good accuracy. However, a more detailed investigation by means of local porosity theory shows that there may be significant differences of the geometrical connectivity between the reconstructed and the experimental samples. PMID:11088546

  7. Stochastic overland flows

    NASA Astrophysics Data System (ADS)

    Govindaraju, R. S.; Kavvas, M. L.

    1991-06-01

    The theory developed in Part I of this paper is now applied to study the probabilistic behavior of the depth at the outlet of an impermeable overland flow section under the diffusion and kinematic wave approximations. This process is excited by stochastic rainfields which are conceptualized from radar observations. The depth at the outflow section is of prime importance and the solution methodology concentrates on obtaining the evolutionary probability distribution function for this physical quantity. This theoretical distribution is then compared with the empirical distribution function obtained from a thousand Monte-Carlo simulations. The simplified theory leading to the Fokker-Planck equation is also investigated. It is observed that the ‘time window’ used for simulation purposes can affect the results. The theoretical methodology performs satisfactorily when compared to simulation results. Some of the notable features of the proposed methodology are presented and further suggestions for improvement and extension of this work are discussed.

  8. Diffusion with stochastic resetting.

    PubMed

    Evans, Martin R; Majumdar, Satya N

    2011-04-22

    We study simple diffusion where a particle stochastically resets to its initial position at a constant rate r. A finite resetting rate leads to a nonequilibrium stationary state with non-Gaussian fluctuations for the particle position. We also show that the mean time to find a stationary target by a diffusive searcher is finite and has a minimum value at an optimal resetting rate r*. Resetting also alters fundamentally the late time decay of the survival probability of a stationary target when there are multiple searchers: while the typical survival probability decays exponentially with time, the average decays as a power law with an exponent depending continuously on the density of searchers. PMID:21599344

  9. Stochastic geometry of turbulence

    NASA Astrophysics Data System (ADS)

    Falkovich, Gregory

    2012-02-01

    Geometric statistics open the window into the most fundamental aspect of turbulence flows, their symmetries, both broken and emerging. On one hand, the study of the stochastic geometry of multi-point configurations reveals the statistical conservation laws which are responsible for the breakdown of scale invariance in direct turbulence cascades. On the other hand, the numerical and experimental studies of inverse cascade reveal that some families of isolines can be mapped to a Brownian walk (i.e. belong to the so-called SLE class) and are thus not only scale invariant but conformally invariant. That means that some aspects of turbulence statistics can be probably described by a conformal field theory. The talk is a review of broken and emerging symmetries in turbulence statistics.

  10. Allocation Management Solutions for High Performance Computing

    SciTech Connect

    Jackson, Scott M.

    2006-04-01

    High Performance Computing sites face unique problems due to the large number of projects and users competing for their resources. The use of an allocation manager can help alleviate some of these problems. This paper addresses some typical allocation problems faced by HPC managers and describes some possible solutions. The Gold Allocation Manager is presented as a case-study that implements a subset of the described solutions.

  11. Stochastic reinforcement benefits skill acquisition

    PubMed Central

    Dayan, Eran; Averbeck, Bruno B.; Richmond, Barry J.; Cohen, Leonardo G.

    2014-01-01

    Learning complex skills is driven by reinforcement, which facilitates both online within-session gains and retention of the acquired skills. Yet, in ecologically relevant situations, skills are often acquired when mapping between actions and rewarding outcomes is unknown to the learning agent, resulting in reinforcement schedules of a stochastic nature. Here we trained subjects on a visuomotor learning task, comparing reinforcement schedules with higher, lower, or no stochasticity. Training under higher levels of stochastic reinforcement benefited skill acquisition, enhancing both online gains and long-term retention. These findings indicate that the enhancing effects of reinforcement on skill acquisition depend on reinforcement schedules. PMID:24532838

  12. A stochastic multi-symplectic scheme for stochastic Maxwell equations with additive noise

    SciTech Connect

    Hong, Jialin; Zhang, Liying

    2014-07-01

    In this paper we investigate a stochastic multi-symplectic method for stochastic Maxwell equations with additive noise. Based on the stochastic version of variational principle, we find a way to obtain the stochastic multi-symplectic structure of three-dimensional (3-D) stochastic Maxwell equations with additive noise. We propose a stochastic multi-symplectic scheme and show that it preserves the stochastic multi-symplectic conservation law and the local and global stochastic energy dissipative properties, which the equations themselves possess. Numerical experiments are performed to verify the numerical behaviors of the stochastic multi-symplectic scheme.

  13. Computational models and resource allocation for supercomputers

    NASA Technical Reports Server (NTRS)

    Mauney, Jon; Agrawal, Dharma P.; Harcourt, Edwin A.; Choe, Young K.; Kim, Sukil

    1989-01-01

    There are several different architectures used in supercomputers, with differing computational models. These different models present a variety of resource allocation problems that must be solved. The computational needs of a program must be cast in terms of the computational model supported by the supercomputer, and this must be done in a way that makes effective use of the machine's resources. This is the resource allocation problem. The computational models of available supercomputers and the associated resource allocation techniques are surveyed. It is shown that many problems and solutions appear repeatedly in very different computing environments. Some case studies are presented, showing concrete computational models and the allocation strategies used.

  14. Model for stochastic-resonance-type behavior in sensory perception

    NASA Astrophysics Data System (ADS)

    Gong, Yunfan; Matthews, Nestor; Qian, Ning

    2002-03-01

    Recently it was found that noise could help improve human detection of sensory stimuli via stochastic-resonance-type behavior. Specifically, the ability of an individual to detect a weak tactile stimulus could be enhanced by adding a certain amount of noise. Here we propose, from the perspective of classical signal detection theory, a simple and general model to elucidate the mechanism underlying this phenomenon. We demonstrate that noise-mediated enhancements and decrements in human sensation can be well reproduced by our model. The predicted upper bound of the performance improvement by adding noise is also consistent with the experimental data. We suggest additional experiments to further test the model.

  15. Improving interdependent networks robustness by adding connectivity links

    NASA Astrophysics Data System (ADS)

    Ji, Xingpei; Wang, Bo; Liu, Dichen; Chen, Guo; Tang, Fei; Wei, Daqian; Tu, Lian

    2016-02-01

    Compared with a single and isolated network, interdependent networks have two types of links: connectivity link and dependency link. This paper aims to improve the robustness of interdependent networks by adding connectivity links. Firstly, interdependent networks failure model and four frequently used link addition strategies are briefly reviewed. Furthermore, by defining inter degree-degree difference, two novel link addition strategies are proposed. Finally, we verify the effectiveness of our proposed link addition strategies by comparing with the current link addition strategies in three different network models. The simulation results show that, given the number of added links, link allocation strategies have great effects on the robustness of interdependent networks, i.e., the double-network link allocation strategy is superior to single-network link allocation strategy. Link addition strategies proposed in this paper excel the current strategies, especially for BA interdependent networks. Moreover, our work can provide guidance on how to allocate limited resources to an existing interdependent networks system and optimize its topology to avoid the potential cascade failures.

  16. Divergence in plant and microbial allocation strategies explains continental patterns in microbial allocation and biogeochemical fluxes.

    PubMed

    Averill, Colin

    2014-10-01

    Allocation trade-offs shape ecological and biogeochemical phenomena at local to global scale. Plant allocation strategies drive major changes in ecosystem carbon cycling. Microbial allocation to enzymes that decompose carbon vs. organic nutrients may similarly affect ecosystem carbon cycling. Current solutions to this allocation problem prioritise stoichiometric tradeoffs implemented in plant ecology. These solutions may not maximise microbial growth and fitness under all conditions, because organic nutrients are also a significant carbon resource for microbes. I created multiple allocation frameworks and simulated microbial growth using a microbial explicit biogeochemical model. I demonstrate that prioritising stoichiometric trade-offs does not optimise microbial allocation, while exploiting organic nutrients as carbon resources does. Analysis of continental-scale enzyme data supports the allocation patterns predicted by this framework, and modelling suggests large deviations in soil C loss based on which strategy is implemented. Therefore, understanding microbial allocation strategies will likely improve our understanding of carbon cycling and climate. PMID:25040202

  17. Constant time worker thread allocation via configuration caching

    SciTech Connect

    Eichenberger, Alexandre E; O'Brien, John K. P.

    2014-11-04

    Mechanisms are provided for allocating threads for execution of a parallel region of code. A request for allocation of worker threads to execute the parallel region of code is received from a master thread. Cached thread allocation information identifying prior thread allocations that have been performed for the master thread are accessed. Worker threads are allocated to the master thread based on the cached thread allocation information. The parallel region of code is executed using the allocated worker threads.

  18. Stability analysis of multi-group deterministic and stochastic epidemic models with vaccination rate

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Gang; Gao, Rui-Mei; Fan, Xiao-Ming; Han, Qi-Xing

    2014-09-01

    We discuss in this paper a deterministic multi-group MSIR epidemic model with a vaccination rate, the basic reproduction number ℛ0, a key parameter in epidemiology, is a threshold which determines the persistence or extinction of the disease. By using Lyapunov function techniques, we show if ℛ0 is greater than 1 and the deterministic model obeys some conditions, then the disease will prevail, the infective persists and the endemic state is asymptotically stable in a feasible region. If ℛ0 is less than or equal to 1, then the infective disappear so the disease dies out. In addition, stochastic noises around the endemic equilibrium will be added to the deterministic MSIR model in order that the deterministic model is extended to a system of stochastic ordinary differential equations. In the stochastic version, we carry out a detailed analysis on the asymptotic behavior of the stochastic model. In addition, regarding the value of ℛ0, when the stochastic system obeys some conditions and ℛ0 is greater than 1, we deduce the stochastic system is stochastically asymptotically stable. Finally, the deterministic and stochastic model dynamics are illustrated through computer simulations.

  19. Using genetic algorithm to solve a new multi-period stochastic optimization model

    NASA Astrophysics Data System (ADS)

    Zhang, Xin-Li; Zhang, Ke-Cun

    2009-09-01

    This paper presents a new asset allocation model based on the CVaR risk measure and transaction costs. Institutional investors manage their strategic asset mix over time to achieve favorable returns subject to various uncertainties, policy and legal constraints, and other requirements. One may use a multi-period portfolio optimization model in order to determine an optimal asset mix. Recently, an alternative stochastic programming model with simulated paths was proposed by Hibiki [N. Hibiki, A hybrid simulation/tree multi-period stochastic programming model for optimal asset allocation, in: H. Takahashi, (Ed.) The Japanese Association of Financial Econometrics and Engineering, JAFFE Journal (2001) 89-119 (in Japanese); N. Hibiki A hybrid simulation/tree stochastic optimization model for dynamic asset allocation, in: B. Scherer (Ed.), Asset and Liability Management Tools: A Handbook for Best Practice, Risk Books, 2003, pp. 269-294], which was called a hybrid model. However, the transaction costs weren't considered in that paper. In this paper, we improve Hibiki's model in the following aspects: (1) The risk measure CVaR is introduced to control the wealth loss risk while maximizing the expected utility; (2) Typical market imperfections such as short sale constraints, proportional transaction costs are considered simultaneously. (3) Applying a genetic algorithm to solve the resulting model is discussed in detail. Numerical results show the suitability and feasibility of our methodology.

  20. Water resources planning and management : A stochastic dual dynamic programming approach

    NASA Astrophysics Data System (ADS)

    Goor, Q.; Pinte, D.; Tilmant, A.

    2008-12-01

    Allocating water between different users and uses, including the environment, is one of the most challenging task facing water resources managers and has always been at the heart of Integrated Water Resources Management (IWRM). As water scarcity is expected to increase over time, allocation decisions among the different uses will have to be found taking into account the complex interactions between water and the economy. Hydro-economic optimization models can capture those interactions while prescribing efficient allocation policies. Many hydro-economic models found in the literature are formulated as large-scale non linear optimization problems (NLP), seeking to maximize net benefits from the system operation while meeting operational and/or institutional constraints, and describing the main hydrological processes. However, those models rarely incorporate the uncertainty inherent to the availability of water, essentially because of the computational difficulties associated stochastic formulations. The purpose of this presentation is to present a stochastic programming model that can identify economically efficient allocation policies in large-scale multipurpose multireservoir systems. The model is based on stochastic dual dynamic programming (SDDP), an extension of traditional SDP that is not affected by the curse of dimensionality. SDDP identify efficient allocation policies while considering the hydrologic uncertainty. The objective function includes the net benefits from the hydropower and irrigation sectors, as well as penalties for not meeting operational and/or institutional constraints. To be able to implement the efficient decomposition scheme that remove the computational burden, the one-stage SDDP problem has to be a linear program. Recent developments improve the representation of the non-linear and mildly non- convex hydropower function through a convex hull approximation of the true hydropower function. This model is illustrated on a cascade of 14 reservoirs on the Nile river basin.

  1. 76 FR 32392 - Notice of Allocation Availability (NOAA) Inviting Applications for the CY 2011 Allocation Round...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-06

    ... Community Development Financial Institutions Fund Notice of Allocation Availability (NOAA) Inviting Applications for the CY 2011 Allocation Round of the New Markets Tax Credit Program Announcement Type: Initial announcement of tax credit allocation availability. DATES: Electronic applications must be received by 5...

  2. Stochastic superparameterization in quasigeostrophic turbulence

    SciTech Connect

    Grooms, Ian; Majda, Andrew J.

    2014-08-15

    In this article we expand and develop the authors' recent proposed methodology for efficient stochastic superparameterization algorithms for geophysical turbulence. Geophysical turbulence is characterized by significant intermittent cascades of energy from the unresolved to the resolved scales resulting in complex patterns of waves, jets, and vortices. Conventional superparameterization simulates large scale dynamics on a coarse grid in a physical domain, and couples these dynamics to high-resolution simulations on periodic domains embedded in the coarse grid. Stochastic superparameterization replaces the nonlinear, deterministic eddy equations on periodic embedded domains by quasilinear stochastic approximations on formally infinite embedded domains. The result is a seamless algorithm which never uses a small scale grid and is far cheaper than conventional SP, but with significant success in difficult test problems. Various design choices in the algorithm are investigated in detail here, including decoupling the timescale of evolution on the embedded domains from the length of the time step used on the coarse grid, and sensitivity to certain assumed properties of the eddies (e.g. the shape of the assumed eddy energy spectrum). We present four closures based on stochastic superparameterization which elucidate the properties of the underlying framework: a ‘null hypothesis’ stochastic closure that uncouples the eddies from the mean, a stochastic closure with nonlinearly coupled eddies and mean, a nonlinear deterministic closure, and a stochastic closure based on energy conservation. The different algorithms are compared and contrasted on a stringent test suite for quasigeostrophic turbulence involving two-layer dynamics on a β-plane forced by an imposed background shear. The success of the algorithms developed here suggests that they may be fruitfully applied to more realistic situations. They are expected to be particularly useful in providing accurate and efficient stochastic parameterizations for use in ensemble-based state estimation and prediction.

  3. Activation-induced B cell fates are selected by intracellular stochastic competition.

    PubMed

    Duffy, Ken R; Wellard, Cameron J; Markham, John F; Zhou, Jie H S; Holmberg, Ross; Hawkins, Edwin D; Hasbold, Jhagvaral; Dowling, Mark R; Hodgkin, Philip D

    2012-01-20

    In response to stimulation, B lymphocytes pursue a large number of distinct fates important for immune regulation. Whether each cell's fate is determined by external direction, internal stochastic processes, or directed asymmetric division is unknown. Measurement of times to isotype switch, to develop into a plasmablast, and to divide or to die for thousands of cells indicated that each fate is pursued autonomously and stochastically. As a consequence of competition between these processes, censorship of alternative outcomes predicts intricate correlations that are observed in the data. Stochastic competition can explain how the allocation of a proportion of B cells to each cell fate is achieved. The B cell may exemplify how other complex cell differentiation systems are controlled. PMID:22223740

  4. What Value "Value Added"?

    ERIC Educational Resources Information Center

    Richards, Andrew

    2015-01-01

    Two quantitative measures of school performance are currently used, the average points score (APS) at Key Stage 2 and value-added (VA), which measures the rate of academic improvement between Key Stage 1 and 2. These figures are used by parents and the Office for Standards in Education to make judgements and comparisons. However, simple…

  5. Innovations Without Added Costs

    ERIC Educational Resources Information Center

    Cereghino, Edward

    1974-01-01

    There is no question that we are in a tight money market, and schools are among the first institutions to feel the squeeze. Therefore, when a plan is offered that provides for innovations without added costs, its something worth noting. (Editor)

  6. Introducing ADS Labs

    NASA Astrophysics Data System (ADS)

    Accomazzi, Alberto; Henneken, E.; Grant, C. S.; Kurtz, M. J.; Di Milia, G.; Luker, J.; Thompson, D. M.; Bohlen, E.; Murray, S. S.

    2011-05-01

    ADS Labs is a platform that ADS is introducing in order to test and receive feedback from the community on new technologies and prototype services. Currently, ADS Labs features a new interface for abstract searches, faceted filtering of results, visualization of co-authorship networks, article-level recommendations, and a full-text search service. The streamlined abstract search interface provides a simple, one-box search with options for ranking results based on a paper relevancy, freshness, number of citations, and downloads. In addition, it provides advanced rankings based on collaborative filtering techniques. The faceted filtering interface allows users to narrow search results based on a particular property or set of properties ("facets"), allowing users to manage large lists and explore the relationship between them. For any set or sub-set of records, the co-authorship network can be visualized in an interactive way, offering a view of the distribution of contributors and their inter-relationships. This provides an immediate way to detect groups and collaborations involved in a particular research field. For a majority of papers in Astronomy, our new interface will provide a list of related articles of potential interest. The recommendations are based on a number of factors, including text similarity, citations, and co-readership information. The new full-text search interface allows users to find all instances of particular words or phrases in the body of the articles in our full-text archive. This includes all of the scanned literature in ADS as well as a select portion of the current astronomical literature, including ApJ, ApJS, AJ, MNRAS, PASP, A&A, and soon additional content from Springer journals. Fulltext search results include a list of the matching papers as well as a list of "snippets" of text highlighting the context in which the search terms were found. ADS Labs is available at http://adslabs.org

  7. ADS in a Nutshell

    NASA Astrophysics Data System (ADS)

    Demleitner, M.; Eichhorn, G.; Grant, C. S.; Accomazzi, A.; Murray, S. S.; Kurtz, M. J.

    1999-05-01

    The bibliographic databases maintained by the NASA Astrophysics Data System are updated approximately biweekly with records gathered from over 125 sources all over the world. Data are either sent to us electronically, retrieved by our staff via semi-automated procedures, or entered in our databases through supervised OCR procedures. PERL scripts are run on the data to convert them from their incoming format to our standard format so that they can be added to the master database at SAO. Once new data has been added, separate index files are created for authors, objects, title words, and text word, allowing these fields to be searched for individually or in combination with each other. During the indexing procedure, discipline-specific knowledge is taken into account through the use of rule-based procedures performing string normalization, context-sensitive word translation, and synonym and stop word replacement. Once the master text and index files have been updated at SAO, an automated procedure mirrors the changes in the database to the ADS mirror site via a secure network connection. The use of a public domain software tool called rsync allows incremental updating of the database files, with significant savings in the amount of data being transferred. In the past year, the ADS Abstract Service databases have grown by approximately 30%, including 50% growth in Physics, 25% growth in Astronomy and 10% growth in the Instrumentation datasets. The ADS Abstract Service now contains over 1.4 million abstracts (475K in Astronomy, 430K in Physics, 510K in Instrumentation, and 3K in Preprints), 175,000 journal abstracts, and 115,000 full text articles. In addition, we provide links to over 40,000 electronic HTML articles at other sites, 20,000 PDF articles, and 10,000 postscript articles, as well as many links to other external data sources.

  8. Stochastic cooling in RHIC

    SciTech Connect

    Brennan J. M.; Blaskiewicz, M.; Mernick, K.

    2012-05-20

    The full 6-dimensional [x,x'; y,y'; z,z'] stochastic cooling system for RHIC was completed and operational for the FY12 Uranium-Uranium collider run. Cooling enhances the integrated luminosity of the Uranium collisions by a factor of 5, primarily by reducing the transverse emittances but also by cooling in the longitudinal plane to preserve the bunch length. The components have been deployed incrementally over the past several runs, beginning with longitudinal cooling, then cooling in the vertical planes but multiplexed between the Yellow and Blue rings, next cooling both rings simultaneously in vertical (the horizontal plane was cooled by betatron coupling), and now simultaneous horizontal cooling has been commissioned. The system operated between 5 and 9 GHz and with 3 x 10{sup 8} Uranium ions per bunch and produces a cooling half-time of approximately 20 minutes. The ultimate emittance is determined by the balance between cooling and emittance growth from Intra-Beam Scattering. Specific details of the apparatus and mathematical techniques for calculating its performance have been published elsewhere. Here we report on: the method of operation, results with beam, and comparison of results to simulations.

  9. Stochastic processes in gravitropism.

    PubMed

    Meroz, Yasmine; Bastien, Renaud

    2014-01-01

    In this short review we focus on the role of noise in gravitropism of plants - the reorientation of plants according to the direction of gravity. We briefly introduce the conventional picture of static gravisensing in cells specialized in sensing. This model hinges on the sedimentation of statoliths (high in density and mass relative to other organelles) to the lowest part of the sensing cell. We then present experimental observations that cannot currently be understood within this framework. Lastly we introduce some current alternative models and directions that attempt to incorporate and interpret these experimental observations, including: (i) dynamic sensing, where gravisensing is suggested to be enhanced by stochastic events due to thermal and mechanical noise. These events both effectively lower the threshold of response, and lead to small-distance sedimentation, allowing amplification, and integration of the signal. (ii) The role of the cytoskeleton in signal-to-noise modulation and (iii) in signal transduction. In closing, we discuss directions that seem to either not have been explored, or that are still poorly understood. PMID:25505482

  10. 39 CFR 3060.12 - Asset allocation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Asset allocation. 3060.12 Section 3060.12 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL ACCOUNTING PRACTICES AND TAX RULES FOR THE THEORETICAL COMPETITIVE PRODUCTS ENTERPRISE § 3060.12 Asset allocation. Within 6 months of January 23, 2009, and for...

  11. 50 CFR 660.55 - Allocations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... shared between the limited entry fixed gear, open access, and recreational fisheries as specified through... fixed gear) and the directed open access fishery, as appropriate. (e) Limited entry (LE)/open access (OA... allocations, the allocation between the limited entry (both trawl and fixed gear) and the open...

  12. 50 CFR 660.320 - Allocations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... limited entry gear is open. When the fishery for a vessel's limited entry gear has closed, groundfish caught by that vessel with open access gear will be counted against the open access allocation. All... Indian fishery, is divided into limited entry and open access fisheries. Separate allocations for...

  13. 40 CFR 74.26 - Allocation formula.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Allocation formula. 74.26 Section 74.26 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.26 Allocation formula. (a)...

  14. Acquisitions Allocations: Fairness, Equity and Bundled Pricing.

    ERIC Educational Resources Information Center

    Packer, Donna

    2001-01-01

    Examined the effect of an interdisciplinary Web-based citation database with full text, the ProQuest Research Library, on the Western State University library's acquisitions allocation plan. Used list price of full-text journals to calculate increases in acquisitions funding. A list of articles discussing formula allocation is appended.…

  15. 10 CFR 490.503 - Credit allocation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Credit allocation. 490.503 Section 490.503 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Alternative Fueled Vehicle... described in section 490.507 of this part, DOE shall allocate one credit for each alternative fueled...

  16. 40 CFR 74.26 - Allocation formula.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Allocation formula. 74.26 Section 74.26 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.26 Allocation formula. (a)...

  17. 40 CFR 74.26 - Allocation formula.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Allocation formula. 74.26 Section 74.26 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.26 Allocation formula. (a)...

  18. 42 CFR 457.228 - Cost allocation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... accordance with the requirements contained in subpart E of 45 CFR part 95. Subpart E also sets forth the... 42 Public Health 4 2012-10-01 2012-10-01 false Cost allocation. 457.228 Section 457.228 Public...; Reduction of Federal Medical Payments § 457.228 Cost allocation. A State plan must provide that the...

  19. 42 CFR 433.34 - Cost allocation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Department in accordance with the requirements contained in subpart E of 45 CFR part 95. Subpart E also sets... 42 Public Health 4 2013-10-01 2013-10-01 false Cost allocation. 433.34 Section 433.34 Public... Provisions § 433.34 Cost allocation. A State plan under Title XIX of the Social Security Act must...

  20. 42 CFR 457.228 - Cost allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... accordance with the requirements contained in subpart E of 45 CFR part 95. Subpart E also sets forth the... 42 Public Health 4 2011-10-01 2011-10-01 false Cost allocation. 457.228 Section 457.228 Public...; Reduction of Federal Medical Payments § 457.228 Cost allocation. A State plan must provide that the...

  1. 42 CFR 433.34 - Cost allocation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Department in accordance with the requirements contained in subpart E of 45 CFR part 95. Subpart E also sets... 42 Public Health 4 2012-10-01 2012-10-01 false Cost allocation. 433.34 Section 433.34 Public... Provisions § 433.34 Cost allocation. A State plan under Title XIX of the Social Security Act must...

  2. 42 CFR 433.34 - Cost allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Department in accordance with the requirements contained in subpart E of 45 CFR part 95. Subpart E also sets... 42 Public Health 4 2011-10-01 2011-10-01 false Cost allocation. 433.34 Section 433.34 Public... Provisions § 433.34 Cost allocation. A State plan under Title XIX of the Social Security Act must...

  3. 42 CFR 457.228 - Cost allocation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... accordance with the requirements contained in subpart E of 45 CFR part 95. Subpart E also sets forth the... 42 Public Health 4 2013-10-01 2013-10-01 false Cost allocation. 457.228 Section 457.228 Public...; Reduction of Federal Medical Payments § 457.228 Cost allocation. A State plan must provide that the...

  4. A Time Allocation Study of University Faculty

    ERIC Educational Resources Information Center

    Link, Albert N.; Swann, Christopher A.; Bozeman, Barry

    2008-01-01

    Many previous time allocation studies treat work as a single activity and examine trade-offs between work and other activities. This paper investigates the at-work allocation of time among teaching, research, grant writing and service by science and engineering faculty at top US research universities. We focus on the relationship between tenure

  5. 49 CFR 262.5 - Allocation requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Allocation requirements. 262.5 Section 262.5..., DEPARTMENT OF TRANSPORTATION IMPLEMENTATION OF PROGRAM FOR CAPITAL GRANTS FOR RAIL LINE RELOCATION AND IMPROVEMENT PROJECTS § 262.5 Allocation requirements. At least fifty percent of all grant funds awarded...

  6. 48 CFR 5452.249 - Allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Allocation. 5452.249 Section 5452.249 Federal Acquisition Regulations System DEFENSE LOGISTICS AGENCY, DEPARTMENT OF DEFENSE SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 5452.249 Allocation. The...

  7. 48 CFR 5452.249 - Allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Allocation. 5452.249 Section 5452.249 Federal Acquisition Regulations System DEFENSE LOGISTICS AGENCY, DEPARTMENT OF DEFENSE SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 5452.249 Allocation. The...

  8. Projected 1999-2000 Cost Allocation Summary.

    ERIC Educational Resources Information Center

    Wisconsin Technical Coll. System Board, Madison.

    Information contained in this summary was derived from data submitted by Wisconsin technical colleges on their 1999-2000 projected cost allocation schedules. Cost allocation information is used to calculate the distribution of state aids to each college, and prepare financial and enrollment reports including state statistical summaries and reports…

  9. 50 CFR 600.517 - Allocations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Allocations. 600.517 Section 600.517 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MAGNUSON-STEVENS ACT PROVISIONS Foreign Fishing § 600.517 Allocations. The...

  10. 50 CFR 660.55 - Allocations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... halibut regulations) is managed under regulations at 50 CFR part 300, subpart E. Beginning with the 2011..., the OY is reduced by the Pacific Coast treaty Indian tribal harvest (allocations, set-asides, and...: recreational estimates are not deducted here). (1) Pacific Coast treaty Indian tribal allocations,...

  11. Resource Allocation in Classrooms. Final Report.

    ERIC Educational Resources Information Center

    Thomas, J. Alan

    This report deals with the allocation of resources within classrooms and homes. It is based on the assumption that learning occurs through a set of processes that require the utilization of human and material resources. It is assumed that the study of resource allocation at the micro level will help provide an understanding of the effect on…

  12. Thematic Mapper data for forest resource allocation

    NASA Technical Reports Server (NTRS)

    Zeff, Ilene S.; Merry, Carolyn J.

    1993-01-01

    A technique for classifying a Landsat Thematic Mapper image was demonstrated on the Wayne National Forest of southeastern Ohio. The classified image was integrated into a geographic information system database, and prescriptive forest land use allocation models were developed using the techniques of cartographic modeling. Timber harvest sites and accompanying haul roads were allocated.

  13. Overview of NLCF FY 2006 Allocations

    SciTech Connect

    Tharrington, Arnold N; Messer, Otis; Hoffman, Forrest

    2006-06-01

    The National Center of Computational Sciences is the National leader in capability computing and is designated as the National Leader Computing Facility (NLCF). Breakthrough computational scientific research is being achieved by world class researches in their respective fields. We present an overview of the FY 2006 projects allocated on NLCF. A more detailed overview is given for the projects with the 2 largest allocations.

  14. 45 CFR 205.150 - Cost allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ASSISTANCE PROGRAMS § 205.150 Cost allocation. A State plan under title I, IV-A, X, XIV, or XVI (AABD) of the Social Security Act must provide that the State agency will have an approved cost allocation plan on file with the Department in accordance with the requirements contained in subpart E of 45 CFR part...

  15. 50 CFR 600.517 - Allocations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of State, in cooperation with the Secretary, determines the allocation among foreign nations of fish species and species groups. The Secretary of State officially notifies each foreign nation of its... of an applicable allocation to fishing vessels is upon the foreign nation and the owner or...

  16. 23 CFR 1240.15 - Allocations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Allocations. 1240.15 Section 1240.15 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES SAFETY INCENTIVE GRANTS FOR USE OF SEAT BELTS-ALLOCATIONS BASED ON SEAT BELT USE...

  17. 23 CFR 1240.15 - Allocations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Allocations. 1240.15 Section 1240.15 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES SAFETY INCENTIVE GRANTS FOR USE OF SEAT BELTS-ALLOCATIONS BASED ON SEAT BELT USE...

  18. 23 CFR 1240.15 - Allocations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Allocations. 1240.15 Section 1240.15 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES SAFETY INCENTIVE GRANTS FOR USE OF SEAT BELTS-ALLOCATIONS BASED ON SEAT BELT USE...

  19. 23 CFR 1240.15 - Allocations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Allocations. 1240.15 Section 1240.15 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION AND FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GUIDELINES SAFETY INCENTIVE GRANTS FOR USE OF SEAT BELTS-ALLOCATIONS BASED ON SEAT BELT USE...

  20. Rethinking Reinforcement: Allocation, Induction, and Contingency

    ERIC Educational Resources Information Center

    Baum, William M.

    2012-01-01

    The concept of reinforcement is at least incomplete and almost certainly incorrect. An alternative way of organizing our understanding of behavior may be built around three concepts: "allocation," "induction," and "correlation." Allocation is the measure of behavior and captures the centrality of choice: All behavior entails choice and consists of…

  1. 10 CFR 490.503 - Credit allocation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Credit allocation. 490.503 Section 490.503 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Alternative Fueled Vehicle... described in section 490.507 of this part, DOE shall allocate one credit for each alternative fueled...

  2. 10 CFR 490.503 - Credit allocation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Credit allocation. 490.503 Section 490.503 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Alternative Fueled Vehicle... described in section 490.507 of this part, DOE shall allocate one credit for each alternative fueled...

  3. 10 CFR 490.503 - Credit allocation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Credit allocation. 490.503 Section 490.503 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Alternative Fueled Vehicle... described in section 490.507 of this part, DOE shall allocate one credit for each alternative fueled...

  4. 10 CFR 490.503 - Credit allocation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Credit allocation. 490.503 Section 490.503 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Alternative Fueled Vehicle... described in section 490.507 of this part, DOE shall allocate one credit for each alternative fueled...

  5. Resource Allocation in Public Research Universities

    ERIC Educational Resources Information Center

    Santos, Jose L.

    2007-01-01

    The purpose of this study was to conduct an econometric analysis of internal resource allocation. Two theories are used for this study of resource allocation in public research universities, and these are: (1) Theory of the Firm; and (2) Resource Dependence Theory. This study used the American Association of Universities Data Exchange (AAUDE)…

  6. 48 CFR 5452.249 - Allocation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Allocation. 5452.249 Section 5452.249 Federal Acquisition Regulations System DEFENSE LOGISTICS AGENCY, DEPARTMENT OF DEFENSE SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 5452.249 Allocation. The...

  7. 48 CFR 5452.249 - Allocation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Allocation. 5452.249 Section 5452.249 Federal Acquisition Regulations System DEFENSE LOGISTICS AGENCY, DEPARTMENT OF DEFENSE SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 5452.249 Allocation. The...

  8. Acquisitions Allocations: Fairness, Equity and Bundled Pricing.

    ERIC Educational Resources Information Center

    Packer, Donna

    2001-01-01

    Examined the effect of an interdisciplinary Web-based citation database with full text, the ProQuest Research Library, on the Western State University library's acquisitions allocation plan. Used list price of full-text journals to calculate increases in acquisitions funding. A list of articles discussing formula allocation is appended.

  9. Budget allocation and the analytic hierarchy process

    SciTech Connect

    Hulme, B.L. )

    1990-10-01

    This report demonstrates that the priorities calculated by the Analytic Hierarchy Process can be used as measures of benefit for budget allocation. A procedure is described that optimally allocates a budget among competing DOE waste minimization projects. The projects are compared using an analytic hierarchy already developed by Sandia National Laboratories. 2 refs., 3 tabs.

  10. 45 CFR 98.55 - Cost allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Cost allocation. 98.55 Section 98.55 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CHILD CARE AND DEVELOPMENT FUND Use of Child Care and Development Funds § 98.55 Cost allocation. (a) The Lead Agency and...

  11. Rethinking Reinforcement: Allocation, Induction, and Contingency

    ERIC Educational Resources Information Center

    Baum, William M.

    2012-01-01

    The concept of reinforcement is at least incomplete and almost certainly incorrect. An alternative way of organizing our understanding of behavior may be built around three concepts: "allocation," "induction," and "correlation." Allocation is the measure of behavior and captures the centrality of choice: All behavior entails choice and consists of

  12. 45 CFR 304.15 - Cost allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Department in accordance with the requirements contained in Subpart E of 45 CFR part 95. Subpart E also sets... 45 Public Welfare 2 2011-10-01 2011-10-01 false Cost allocation. 304.15 Section 304.15 Public... FEDERAL FINANCIAL PARTICIPATION § 304.15 Cost allocation. A State agency in support of its claims...

  13. 42 CFR 457.228 - Cost allocation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... accordance with the requirements contained in subpart E of 45 CFR part 95. Subpart E also sets forth the... 42 Public Health 4 2014-10-01 2014-10-01 false Cost allocation. 457.228 Section 457.228 Public...; Reduction of Federal Medical Payments § 457.228 Cost allocation. A State plan must provide that the...

  14. 42 CFR 433.34 - Cost allocation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Department in accordance with the requirements contained in subpart E of 45 CFR part 95. Subpart E also sets... 42 Public Health 4 2014-10-01 2014-10-01 false Cost allocation. 433.34 Section 433.34 Public... Provisions § 433.34 Cost allocation. A State plan under Title XIX of the Social Security Act must...

  15. 45 CFR 205.150 - Cost allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... with the Department in accordance with the requirements contained in subpart E of 45 CFR part 95... 45 Public Welfare 2 2011-10-01 2011-10-01 false Cost allocation. 205.150 Section 205.150 Public... ASSISTANCE PROGRAMS § 205.150 Cost allocation. A State plan under title I, IV-A, X, XIV, or XVI (AABD) of...

  16. 7 CFR 761.205 - Computing the formula allocation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Computing the formula allocation. 761.205 Section 761... Funds to State Offices § 761.205 Computing the formula allocation. (a) The formula allocation for FO or... program that the National Office allocates to a State Office. formula allocation = (amount available...

  17. Choice of Antiviral Allocation Scheme for Pandemic Influenza Depends on Strain Transmissibility, Delivery Delay and Stockpile Size.

    PubMed

    Lydeamore, Michael; Bean, Nigel; Black, Andrew J; Ross, Joshua V

    2016-02-01

    Recently, pandemic response has involved the use of antivirals. These antivirals are often allocated to households dynamically throughout the pandemic with the aim being to retard the spread of infection. A drawback of this is that there is a delay until infection is confirmed and antivirals are delivered. Here an alternative allocation scheme is considered, where antivirals are instead preallocated to households at the start of a pandemic, thus reducing this delay. To compare these two schemes, a deterministic approximation to a novel stochastic household model is derived, which allows efficient computation of key quantities such as the expected epidemic final size, expected early growth rate, expected peak size and expected peak time of the epidemic. It is found that the theoretical best choice of allocation scheme depends on strain transmissibility, the delay in delivering antivirals under a dynamic allocation scheme and the stockpile size. A broad summary is that for realistic stockpile sizes, a dynamic allocation scheme is superior with the important exception of the epidemic final size under a severe pandemic scenario. Our results, viewed in conjunction with the practical considerations of implementing a preallocation scheme, support a focus on attempting to reduce the delay in delivering antivirals under a dynamic allocation scheme during a future pandemic. PMID:26846916

  18. Are Outcome-Adaptive Allocation Trials Ethical?

    PubMed Central

    Hey, Spencer Phillips; Kimmelman, Jonathan

    2015-01-01

    Randomization is firmly established as a cornerstone of clinical trial methodology. Yet, the ethics of randomization continues to generate controversy. The default, and most efficient, allocation scheme randomizes patients equally (1:1) across all arms of study. However, many randomized trials are using outcome-adaptive allocation schemes, which dynamically adjust the allocation ratio in favor of the better-performing treatment arm. Advocates of outcome-adaptive allocation contend that it better accommodates clinical equipoise and promotes informed consent, since such trials limit patient-subject exposure to sub-optimal care. In this essay, we argue that this purported ethical advantage of outcome-adaptive allocation does not stand up to careful scrutiny in the setting of two armed studies and/or early phase research. PMID:25649106

  19. Allocation Variable-Based Probabilistic Algorithm to Deal with Label Switching Problem in Bayesian Mixture Models

    PubMed Central

    Pan, Jia-Chiun; Liu, Chih-Min; Hwu, Hai-Gwo; Huang, Guan-Hua

    2015-01-01

    The label switching problem occurs as a result of the nonidentifiability of posterior distribution over various permutations of component labels when using Bayesian approach to estimate parameters in mixture models. In the cases where the number of components is fixed and known, we propose a relabelling algorithm, an allocation variable-based (denoted by AVP) probabilistic relabelling approach, to deal with label switching problem. We establish a model for the posterior distribution of allocation variables with label switching phenomenon. The AVP algorithm stochastically relabel the posterior samples according to the posterior probabilities of the established model. Some existing deterministic and other probabilistic algorithms are compared with AVP algorithm in simulation studies, and the success of the proposed approach is demonstrated in simulation studies and a real dataset. PMID:26458185

  20. Carbon allocation and accumulation in conifers

    SciTech Connect

    Gower, S.T.; Isebrands, J.G.; Sheriff, D.W.

    1995-07-01

    Forests cover approximately 33% of the land surface of the earth, yet they are responsible for 65% of the annual carbon (C) accumulated by all terrestrial biomes. In general, total C content and net primary production rates are greater for forests than for other biomes, but C budgets differ greatly among forests. Despite several decades of research on forest C budgets, there is still an incomplete understanding of the factors controlling C allocation. Yet, if we are to understand how changing global events such as land use, climate change, atmospheric N deposition, ozone, and elevated atmospheric CO{sub 2} affect the global C budget, a mechanistic understanding of C assimilation, partitioning, and allocation is necessary. The objective of this chapter is to review the major factors that influence C allocation and accumulation in conifer trees and forests. In keeping with the theme of this book, we will focus primarily on evergreen conifers. However, even among evergreen conifers, leaf, canopy, and stand-level C and nutrient allocation patterns differ, often as a function of leaf development and longevity. The terminology related to C allocation literature is often inconsistent, confusing and inadequate for understanding and integrating past and current research. For example, terms often used synonymously to describe C flow or movement include translocation, transport, distribution, allocation, partitioning, apportionment, and biomass allocation. A common terminology is needed because different terms have different meanings to readers. In this paper we use C allocation, partitioning, and accumulation according to the definitions of Dickson and Isebrands (1993). Partitioning is the process of C flow into and among different chemical, storage, and transport pools. Allocation is the distribution of C to different plant parts within the plant (i.e., source to sink). Accumulation is the end product of the process of C allocation.

  1. Camera scheduling and energy allocation for lifetime maximization in user-centric visual sensor networks.

    PubMed

    Yu, Chao; Sharma, Gaurav

    2010-08-01

    We explore camera scheduling and energy allocation strategies for lifetime optimization in image sensor networks. For the application scenarios that we consider, visual coverage over a monitored region is obtained by deploying wireless, battery-powered image sensors. Each sensor camera provides coverage over a part of the monitored region and a central processor coordinates the sensors in order to gather required visual data. For the purpose of maximizing the network operational lifetime, we consider two problems in this setting: a) camera scheduling, i.e., the selection, among available possibilities, of a set of cameras providing the desired coverage at each time instance, and b) energy allocation, i.e., the distribution of total available energy between the camera sensor nodes. We model the network lifetime as a stochastic random variable that depends upon the coverage geometry for the sensors and the distribution of data requests over the monitored region, two key characteristics that distinguish our problem from other wireless sensor network applications. By suitably abstracting this model of network lifetime and utilizing asymptotic analysis, we propose lifetime-maximizing camera scheduling and energy allocation strategies. The effectiveness of the proposed camera scheduling and energy allocation strategies is validated by simulations. PMID:20350857

  2. Optimal dynamic water allocation: Irrigation extractions and environmental tradeoffs in the Murray River, Australia

    NASA Astrophysics Data System (ADS)

    Grafton, R. Quentin; Chu, Hoang Long; Stewardson, Michael; Kompas, Tom

    2011-12-01

    A key challenge in managing semiarid basins, such as in the Murray-Darling in Australia, is to balance the trade-offs between the net benefits of allocating water for irrigated agriculture, and other uses, versus the costs of reduced surface flows for the environment. Typically, water planners do not have the tools to optimally and dynamically allocate water among competing uses. We address this problem by developing a general stochastic, dynamic programming model with four state variables (the drought status, the current weather, weather correlation, and current storage) and two controls (environmental release and irrigation allocation) to optimally allocate water between extractions and in situ uses. The model is calibrated to Australia's Murray River that generates: (1) a robust qualitative result that "pulse" or artificial flood events are an optimal way to deliver environmental flows over and above conveyance of base flows; (2) from 2001 to 2009 a water reallocation that would have given less to irrigated agriculture and more to environmental flows would have generated between half a billion and over 3 billion U.S. dollars in overall economic benefits; and (3) water markets increase optimal environmental releases by reducing the losses associated with reduced water diversions.

  3. Stacking with stochastic cooling

    NASA Astrophysics Data System (ADS)

    Caspers, Fritz; Möhl, Dieter

    2004-10-01

    Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 105 the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some considerations to the 'azimuthal' schemes.

  4. Two Virasoro symmetries in stringy warped AdS3

    NASA Astrophysics Data System (ADS)

    Compère, Geoffrey; Guica, Monica; Rodriguez, Maria J.

    2014-12-01

    We study three-dimensional consistent truncations of type IIB supergravity which admit warped AdS3 solutions. These theories contain subsectors that have no bulk dynamics. We show that the symplectic form for these theories, when restricted to the non-dynamical subsectors, equals the symplectic form for pure Einstein gravity in AdS3. Consequently, for each consistent choice of boundary conditions in AdS3, we can define a consistent phase space in warped AdS3 with identical conserved charges. This way, we easily obtain a Virasoro × Virasoro asymptotic symmetry algebra in warped AdS3; two different types of Virasoro × Kač-Moody symmetries are also consistent alternatives.

  5. A combined linear optimisation methodology for water resources allocation in Alfeios River Basin (Greece) under uncertain and vague system conditions

    NASA Astrophysics Data System (ADS)

    Bekri, Eleni; Yannopoulos, Panayotis; Disse, Markus

    2013-04-01

    In the present study, a combined linear programming methodology, based on Li et al. (2010) and Bekri et al. (2012), is employed for optimizing water allocation under uncertain system conditions in the Alfeios River Basin, in Greece. The Alfeios River is a water resources system of great natural, ecological, social and economic importance for Western Greece, since it has the longest and highest flow rate watercourse in the Peloponnisos region. Moreover, the river basin was exposed in the last decades to a plethora of environmental stresses (e.g. hydrogeological alterations, intensively irrigated agriculture, surface and groundwater overexploitation and infrastructure developments), resulting in the degradation of its quantitative and qualitative characteristics. As in most Mediterranean countries, water resource management in Alfeios River Basin has been focused up to now on an essentially supply-driven approach. It is still characterized by a lack of effective operational strategies. Authority responsibility relationships are fragmented, and law enforcement and policy implementation are weak. The present regulated water allocation puzzle entails a mixture of hydropower generation, irrigation, drinking water supply and recreational activities. Under these conditions its water resources management is characterised by high uncertainty and by vague and imprecise data. The considered methodology has been developed in order to deal with uncertainties expressed as either probability distributions, or/and fuzzy boundary intervals, derived by associated α-cut levels. In this framework a set of deterministic submodels is studied through linear programming. The ad hoc water resources management and alternative management patterns in an Alfeios subbasin are analyzed and evaluated under various scenarios, using the above mentioned methodology, aiming to promote a sustainable and equitable water management. Li, Y.P., Huang, G.H. and S.L., Nie, (2010), Planning water resources management systems using a fuzzy-boundary interval-stochastic programming method, Elsevier Ltd, Advances in Water Resources, 33: 1105-1117. doi:10.1016/j.advwatres.2010.06.015 Bekri, E.S., Disse, M. and P.C.,Yannopoulos, (2012), Methodological framework for correction of quick river discharge measurements using quality characteristics, Session of Environmental Hydraulics - Hydrodynamics, 2nd Common Conference of Hellenic Hydrotechnical Association and Greek Committee for Water Resources Management, Volume: 546-557 (in Greek).

  6. Control Allocation with Load Balancing

    NASA Technical Reports Server (NTRS)

    Bodson, Marc; Frost, Susan A.

    2009-01-01

    Next generation aircraft with a large number of actuators will require advanced control allocation methods to compute the actuator commands needed to follow desired trajectories while respecting system constraints. Previously, algorithms were proposed to minimize the l1 or l2 norms of the tracking error and of the actuator deflections. The paper discusses the alternative choice of the l(infinity) norm, or sup norm. Minimization of the control effort translates into the minimization of the maximum actuator deflection (min-max optimization). The paper shows how the problem can be solved effectively by converting it into a linear program and solving it using a simplex algorithm. Properties of the algorithm are also investigated through examples. In particular, the min-max criterion results in a type of load balancing, where the load is th desired command and the algorithm balances this load among various actuators. The solution using the l(infinity) norm also results in better robustness to failures and to lower sensitivity to nonlinearities in illustrative examples.

  7. Time allocation of disabled individuals.

    PubMed

    Pagán, Ricardo

    2013-05-01

    Although some studies have analysed the disability phenomenon and its effect on, for example, labour force participation, wages, job satisfaction, or the use of disability pension, the empirical evidence on how disability steals time (e.g. hours of work) from individuals is very scarce. This article examines how disabled individuals allocate their time to daily activities as compared to their non-disabled counterparts. Using time diary information from the Spanish Time Use Survey (last quarter of 2002 and the first three quarters of 2003), we estimate the determinants of time (minutes per day) spent on four aggregate categories (market work, household production, tertiary activities and leisure) for a sample of 27,687 non-disabled and 5250 disabled individuals and decompose the observed time differential by using the Oaxaca-Blinder methodology. The results show that disabled individuals devote less time to market work (especially females), and more time to household production (e.g. cooking, cleaning, child care), tertiary activities (e.g., sleeping, personal care, medical treatment) and leisure activities. We also find a significant effect of age on the time spent on daily activities and important differences by gender and disability status. The results are consistent with the hypothesis that disability steals time, and reiterate the fact that more public policies are needed to balance working life and health concerns among disabled individuals. PMID:23517707

  8. Supersymmetric AdS6 via T duality.

    PubMed

    Lozano, Y; Colgáin, E Ó; Rodríguez-Gómez, D; Sfetsos, K

    2013-06-01

    We present a new supersymmetric AdS(6) solution of type IIB supergravity with SU(2) isometry. Through the AdS/CFT correspondence, this has potentially very interesting implications for 5D fixed point theories. This solution is the result of a non-Abelian T duality on the known supersymmetric AdS(6) solution of massive IIA. The SU(2) R symmetry is untouched, leading to sixteen supercharges and preserved supersymmetry. PMID:25167481

  9. A Stochastic Collocation Algorithm for Uncertainty Analysis

    NASA Technical Reports Server (NTRS)

    Mathelin, Lionel; Hussaini, M. Yousuff; Zang, Thomas A. (Technical Monitor)

    2003-01-01

    This report describes a stochastic collocation method to adequately handle a physically intrinsic uncertainty in the variables of a numerical simulation. For instance, while the standard Galerkin approach to Polynomial Chaos requires multi-dimensional summations over the stochastic basis functions, the stochastic collocation method enables to collapse those summations to a one-dimensional summation only. This report furnishes the essential algorithmic details of the new stochastic collocation method and provides as a numerical example the solution of the Riemann problem with the stochastic collocation method used for the discretization of the stochastic parameters.

  10. Shift-invariant target in allocation problems.

    PubMed

    Mandal, Saumen; Biswas, Atanu

    2014-07-10

    We provide a template for finding target allocation proportions in optimal allocation designs where the target will be invariant for both shifts in location and scale of the response distributions. One possible application of such target allocation proportions is to carry out a response-adaptive allocation. While most of the existing designs are invariant for any change in scale of the underlying distributions, they are not location invariant in most of the cases. First, we indicate this serious flaw in the existing literature and illustrate how this lack of location invariance makes the performance of the designs very poor in terms of allocation for any drastic change in location, such as the changes from degrees centigrade to degrees Fahrenheit. We illustrate that unless a target allocation is location invariant, it might lead to a completely irrelevant and useless target for allocation. Then we discuss how such location invariance can be achieved for general continuous responses. We illustrate the proposed method using some real clinical trial data. We also indicate the possible extension of the procedure for more than two treatments at hand and in the presence of covariates. PMID:24549681

  11. Stochastic simulation in systems biology

    PubMed Central

    Székely, Tamás; Burrage, Kevin

    2014-01-01

    Natural systems are, almost by definition, heterogeneous: this can be either a boon or an obstacle to be overcome, depending on the situation. Traditionally, when constructing mathematical models of these systems, heterogeneity has typically been ignored, despite its critical role. However, in recent years, stochastic computational methods have become commonplace in science. They are able to appropriately account for heterogeneity; indeed, they are based around the premise that systems inherently contain at least one source of heterogeneity (namely, intrinsic heterogeneity). In this mini-review, we give a brief introduction to theoretical modelling and simulation in systems biology and discuss the three different sources of heterogeneity in natural systems. Our main topic is an overview of stochastic simulation methods in systems biology. There are many different types of stochastic methods. We focus on one group that has become especially popular in systems biology, biochemistry, chemistry and physics. These discrete-state stochastic methods do not follow individuals over time; rather they track only total populations. They also assume that the volume of interest is spatially homogeneous. We give an overview of these methods, with a discussion of the advantages and disadvantages of each, and suggest when each is more appropriate to use. We also include references to software implementations of them, so that beginners can quickly start using stochastic methods for practical problems of interest. PMID:25505503

  12. Transcriptional stochasticity in gene expression.

    PubMed

    Lipniacki, Tomasz; Paszek, Pawel; Marciniak-Czochra, Anna; Brasier, Allan R; Kimmel, Marek

    2006-01-21

    Due to the small number of copies of molecular species involved, such as DNA, mRNA and regulatory proteins, gene expression is a stochastic phenomenon. In eukaryotic cells, the stochastic effects primarily originate in regulation of gene activity. Transcription can be initiated by a single transcription factor binding to a specific regulatory site in the target gene. Stochasticity of transcription factor binding and dissociation is then amplified by transcription and translation, since target gene activation results in a burst of mRNA molecules, and each mRNA copy serves as a template for translating numerous protein molecules. In the present paper, we explore a mathematical approach to stochastic modeling. In this approach, the ordinary differential equations with a stochastic component for mRNA and protein levels in a single cells yield a system of first-order partial differential equations (PDEs) for two-dimensional probability density functions (pdf). We consider the following examples: Regulation of a single auto-repressing gene, and regulation of a system of two mutual repressors and of an activator-repressor system. The resulting PDEs are approximated by a system of many ordinary equations, which are then numerically solved. PMID:16039671

  13. Stochastic simulation in systems biology.

    PubMed

    Székely, Tamás; Burrage, Kevin

    2014-11-01

    Natural systems are, almost by definition, heterogeneous: this can be either a boon or an obstacle to be overcome, depending on the situation. Traditionally, when constructing mathematical models of these systems, heterogeneity has typically been ignored, despite its critical role. However, in recent years, stochastic computational methods have become commonplace in science. They are able to appropriately account for heterogeneity; indeed, they are based around the premise that systems inherently contain at least one source of heterogeneity (namely, intrinsic heterogeneity). In this mini-review, we give a brief introduction to theoretical modelling and simulation in systems biology and discuss the three different sources of heterogeneity in natural systems. Our main topic is an overview of stochastic simulation methods in systems biology. There are many different types of stochastic methods. We focus on one group that has become especially popular in systems biology, biochemistry, chemistry and physics. These discrete-state stochastic methods do not follow individuals over time; rather they track only total populations. They also assume that the volume of interest is spatially homogeneous. We give an overview of these methods, with a discussion of the advantages and disadvantages of each, and suggest when each is more appropriate to use. We also include references to software implementations of them, so that beginners can quickly start using stochastic methods for practical problems of interest. PMID:25505503

  14. Enhanced algorithms for stochastic programming

    SciTech Connect

    Krishna, A.S.

    1993-09-01

    In this dissertation, we present some of the recent advances made in solving two-stage stochastic linear programming problems of large size and complexity. Decomposition and sampling are two fundamental components of techniques to solve stochastic optimization problems. We describe improvements to the current techniques in both these areas. We studied different ways of using importance sampling techniques in the context of Stochastic programming, by varying the choice of approximation functions used in this method. We have concluded that approximating the recourse function by a computationally inexpensive piecewise-linear function is highly efficient. This reduced the problem from finding the mean of a computationally expensive functions to finding that of a computationally inexpensive function. Then we implemented various variance reduction techniques to estimate the mean of a piecewise-linear function. This method achieved similar variance reductions in orders of magnitude less time than, when we directly applied variance-reduction techniques directly on the given problem. In solving a stochastic linear program, the expected value problem is usually solved before a stochastic solution and also to speed-up the algorithm by making use of the information obtained from the solution of the expected value problem. We have devised a new decomposition scheme to improve the convergence of this algorithm.

  15. Stochastic optimal control of spacecraft

    NASA Astrophysics Data System (ADS)

    Gustafson, Eric Daniel

    This dissertation studies the influence of uncertainty on spacecraft control. The sources of the uncertainty are either imperfect state measurements or stochastic acceleration due to thruster noise. First, we analyze the impact of uncertainty in state measurements on the long-term cost of controlling an unstable periodic system. Under a specific procedure for updating control laws, we show that for unstable systems, there is an optimal time to perform updates in order to minimize the long-term cost per unit time. Second, we consider the effect of stochastic acceleration due to thruster noise, which results in multiplicative noise on the control. Feedback control laws are obtained by numerically solving the stochastic Hamilton-Jacobi-Bellman equation using the spectral method. The optimal feedback control law for realistic noise levels is shown to differ significantly from the deterministic control. This suggests that trajectory planning would benefit from the inclusion of these stochastic effects. Finally, we show that Taylor series expansions can be also be used to solve the stochastic Hamilton-Jacobi-Bellman equation under the fairly nonrestrictive assumption that the expansion is performed about an equilibrium point and that the gradient of the value function about the expansion point is zero. The Taylor series approach produces a system of ordinary differential equations describing the evolution of the coefficients in the power series. We show that in steady-state, a proper Taylor series may not exist, and that the proper solution is obtained through a Frobenius series expansion.

  16. Stochastic models: theory and simulation.

    SciTech Connect

    Field, Richard V., Jr.

    2008-03-01

    Many problems in applied science and engineering involve physical phenomena that behave randomly in time and/or space. Examples are diverse and include turbulent flow over an aircraft wing, Earth climatology, material microstructure, and the financial markets. Mathematical models for these random phenomena are referred to as stochastic processes and/or random fields, and Monte Carlo simulation is the only general-purpose tool for solving problems of this type. The use of Monte Carlo simulation requires methods and algorithms to generate samples of the appropriate stochastic model; these samples then become inputs and/or boundary conditions to established deterministic simulation codes. While numerous algorithms and tools currently exist to generate samples of simple random variables and vectors, no cohesive simulation tool yet exists for generating samples of stochastic processes and/or random fields. There are two objectives of this report. First, we provide some theoretical background on stochastic processes and random fields that can be used to model phenomena that are random in space and/or time. Second, we provide simple algorithms that can be used to generate independent samples of general stochastic models. The theory and simulation of random variables and vectors is also reviewed for completeness.

  17. Variance decomposition in stochastic simulators.

    PubMed

    Le Maître, O P; Knio, O M; Moraes, A

    2015-06-28

    This work aims at the development of a mathematical and computational approach that enables quantification of the inherent sources of stochasticity and of the corresponding sensitivities in stochastic simulations of chemical reaction networks. The approach is based on reformulating the system dynamics as being generated by independent standardized Poisson processes. This reformulation affords a straightforward identification of individual realizations for the stochastic dynamics of each reaction channel, and consequently a quantitative characterization of the inherent sources of stochasticity in the system. By relying on the Sobol-Hoeffding decomposition, the reformulation enables us to perform an orthogonal decomposition of the solution variance. Thus, by judiciously exploiting the inherent stochasticity of the system, one is able to quantify the variance-based sensitivities associated with individual reaction channels, as well as the importance of channel interactions. Implementation of the algorithms is illustrated in light of simulations of simplified systems, including the birth-death, Schlögl, and Michaelis-Menten models. PMID:26133418

  18. Dynamic Allocation of Sugars in Barley

    NASA Astrophysics Data System (ADS)

    Cumberbatch, L. C.; Crowell, A. S.; Fallin, B. A.; Howell, C. R.; Reid, C. D.; Weisenberger, A. G.; Lee, S. J.; McKisson, J. E.

    2014-03-01

    Allocation of carbon and nitrogen is a key factor for plant productivity. Measurements are carried out by tracing 11C-tagged sugars using positron emission tomography and coincidence counting. We study the mechanisms of carbon allocation and transport from carbohydrate sources (leaves) to sinks (stem, shoot, roots) under various environmental conditions such as soil nutrient levels and atmospheric CO2 concentration. The data are analyzed using a transfer function analysis technique to model transport and allocation in barley plants. The experimental technique will be described and preliminary results presented. This work was supported in part by USDOE Grant No. DE-FG02-97-ER41033 and DE-SC0005057.

  19. Allocation models for DMUs with negative data

    NASA Astrophysics Data System (ADS)

    Tohidi, Ghasem; Khodadadi, Maryam

    2013-06-01

    The formulas of cost and allocative efficiencies of decision making units (DMUs) with positive data cannot be used for DMUs with negative data. On the other hand, these formulas are needed to analyze the productivity and performance of DMUs with negative data. To this end, this study introduces the cost and allocative efficiencies of DMUs with negative data and demonstrates that the introduced cost efficiency is equal to the product of allocative and range directional measure efficiencies. The study then intends to extend the definition of the above efficiencies to DMUs with negative data and different unit costs. Finally, two numerical examples are given to illustrate the proposed methods.

  20. CMOS-compatible active thermopiles for noise-added theory

    NASA Astrophysics Data System (ADS)

    Shen, Chih-Hsiung; Hou, Kuan-Chou

    2004-05-01

    Recently a novel signal processing theory related with noise has grown and proven. Certain complex systems can improve performance with added optimal noise that classical theory cannot explain. Their behavior may be represented by a simplified scheme that combines both a deterministic and stochastic source. To that end, we are using noise in remote temperature sensing system to enhance their function without altering the system. A new investigation of noise added scheme has been realized by an embedded heater for CMOS compatible thermoelectric infrared sensor. The design and fabrication of thermopile sensors are realized by using 1.2μm CMOS IC technology combined with a subsequent anisotropic front-side etching. We firstly develop an active thermopile with a heater embedded which is easily and naturally driven by a noise generation circuit. The stochastic resonance theory can be realized as a reduction in threshold of temperature detection. We have shown the possibility of improving the performance of remote temperature sensing system in the presence of noise. The strategy depends on the application. Stochastic resonance can reduce threshold detection resolution and greatly improve the temperature detection limit with a low cost scheme without using higher resolution ADC.

  1. On square-wave-driven stochastic resonance for energy harvesting in a bistable system

    SciTech Connect

    Su, Dongxu; Zheng, Rencheng; Nakano, Kimihiko; Cartmell, Matthew P

    2014-11-15

    Stochastic resonance is a physical phenomenon through which the throughput of energy within an oscillator excited by a stochastic source can be boosted by adding a small modulating excitation. This study investigates the feasibility of implementing square-wave-driven stochastic resonance to enhance energy harvesting. The motivating hypothesis was that such stochastic resonance can be efficiently realized in a bistable mechanism. However, the condition for the occurrence of stochastic resonance is conventionally defined by the Kramers rate. This definition is inadequate because of the necessity and difficulty in estimating white noise density. A bistable mechanism has been designed using an explicit analytical model which implies a new approach for achieving stochastic resonance in the paper. Experimental tests confirm that the addition of a small-scale force to the bistable system excited by a random signal apparently leads to a corresponding amplification of the response that we now term square-wave-driven stochastic resonance. The study therefore indicates that this approach may be a promising way to improve the performance of an energy harvester under certain forms of random excitation.

  2. On square-wave-driven stochastic resonance for energy harvesting in a bistable system

    NASA Astrophysics Data System (ADS)

    Su, Dongxu; Zheng, Rencheng; Nakano, Kimihiko; Cartmell, Matthew P.

    2014-11-01

    Stochastic resonance is a physical phenomenon through which the throughput of energy within an oscillator excited by a stochastic source can be boosted by adding a small modulating excitation. This study investigates the feasibility of implementing square-wave-driven stochastic resonance to enhance energy harvesting. The motivating hypothesis was that such stochastic resonance can be efficiently realized in a bistable mechanism. However, the condition for the occurrence of stochastic resonance is conventionally defined by the Kramers rate. This definition is inadequate because of the necessity and difficulty in estimating white noise density. A bistable mechanism has been designed using an explicit analytical model which implies a new approach for achieving stochastic resonance in the paper. Experimental tests confirm that the addition of a small-scale force to the bistable system excited by a random signal apparently leads to a corresponding amplification of the response that we now term square-wave-driven stochastic resonance. The study therefore indicates that this approach may be a promising way to improve the performance of an energy harvester under certain forms of random excitation.

  3. The comparative topology of energy allocation in budget models

    NASA Astrophysics Data System (ADS)

    Lika, Konstadia; Kooijman, Sebastiaan A. L. M.

    2011-11-01

    The standard Dynamic Energy Budget (DEB) model assumes that assimilates of an isomorphic individual are first added to reserve, a fraction κ of mobilised reserve is allocated to soma (somatic maintenance plus growth of structure), and the rest to maturity maintenance and maturation or reproduction. Food, reserve and structure have constant chemical composition. We here discuss all possible topological alternatives to the standard DEB model, and compare them on the basis of seven properties: the ability to capture weak homeostasis and general empirical growth and reproduction patterns. We selected a reserve dynamics such that reserve mobilisation rate is independent of assimilation, somatic maintenance is proportional to the amount of structure, maturity maintenance to the level of maturity, and assimilation to the surface area. The alternatives only differ from the standard DEB model in topology, but we drop the κ-rule and allow κ to vary with the amount of structure. For this purpose we introduce the concept 'generalised von Bertalanffy growth rate' and study how it behaves as a function of the ultimate structural length, both intra- and inter-specifically. The 21 derived topological alternatives of the standard DEB are classified into five classes of models, depending on the first allocation event for the assimilation flux. The possibilities of the first allocation event for the assimilation flux are: splitting ( κ-models), storing ( A-models), both maintenance fluxes simultaneously ( P-models), somatic maintenance ( S-models) or maturity maintenance ( J-models). We conclude that the standard DEB model with constant κ is the only one that passes all our tests successfully. Only assimilation ( A) models can naturally accommodate embryo development. The κ-models, which after splitting the fraction 1- κ of assimilates is allocated to maturity maintenance and maturity/reproduction while the fraction κ of assimilates is first stored in reserve or allocated to somatic maintenance, pass most tests, but have maturation and reproduction directly from food. So, embryos have to do this differently and reproduction is prohibited during starvation in these models.

  4. Stochastic decision analysis

    NASA Technical Reports Server (NTRS)

    Lacksonen, Thomas A.

    1994-01-01

    Small space flight project design at NASA Langley Research Center goes through a multi-phase process from preliminary analysis to flight operations. The process insures that each system achieves its technical objectives with demonstrated quality and within planned budgets and schedules. A key technical component of early phases is decision analysis, which is a structure procedure for determining the best of a number of feasible concepts based upon project objectives. Feasible system concepts are generated by the designers and analyzed for schedule, cost, risk, and technical measures. Each performance measure value is normalized between the best and worst values and a weighted average score of all measures is calculated for each concept. The concept(s) with the highest scores are retained, while others are eliminated from further analysis. This project automated and enhanced the decision analysis process. Automation of the decision analysis process was done by creating a user-friendly, menu-driven, spreadsheet macro based decision analysis software program. The program contains data entry dialog boxes, automated data and output report generation, and automated output chart generation. The enhancements to the decision analysis process permit stochastic data entry and analysis. Rather than enter single measure values, the designers enter the range and most likely value for each measure and concept. The data can be entered at the system or subsystem level. System level data can be calculated as either sum, maximum, or product functions of the subsystem data. For each concept, the probability distributions are approximated for each measure and the total score for each concept as either constant, triangular, normal, or log-normal distributions. Based on these distributions, formulas are derived for the probability that the concept meets any given constraint, the probability that the concept meets all constraints, and the probability that the concept is within a given amount of the best score. Formulas are also derived for the probability that one concept's total score is within a given amount of a second concept's total score. These probabilistic calculations provide more realistic data entry and output information for designers, enabling designers to better determine which concepts to eliminate and which concepts to retain at the decision points of each design phase.

  5. Nonlinear optimization for stochastic simulations.

    SciTech Connect

    Johnson, Michael M.; Yoshimura, Ann S.; Hough, Patricia Diane; Ammerlahn, Heidi R.

    2003-12-01

    This report describes research targeting development of stochastic optimization algorithms and their application to mission-critical optimization problems in which uncertainty arises. The first section of this report covers the enhancement of the Trust Region Parallel Direct Search (TRPDS) algorithm to address stochastic responses and the incorporation of the algorithm into the OPT++ optimization library. The second section describes the Weapons of Mass Destruction Decision Analysis Center (WMD-DAC) suite of systems analysis tools and motivates the use of stochastic optimization techniques in such non-deterministic simulations. The third section details a batch programming interface designed to facilitate criteria-based or algorithm-driven execution of system-of-system simulations. The fourth section outlines the use of the enhanced OPT++ library and batch execution mechanism to perform systems analysis and technology trade-off studies in the WMD detection and response problem domain.

  6. Stochastic determination of matrix determinants.

    PubMed

    Dorn, Sebastian; Ensslin, Torsten A

    2015-07-01

    Matrix determinants play an important role in data analysis, in particular when Gaussian processes are involved. Due to currently exploding data volumes, linear operations-matrices-acting on the data are often not accessible directly but are only represented indirectly in form of a computer routine. Such a routine implements the transformation a data vector undergoes under matrix multiplication. While efficient probing routines to estimate a matrix's diagonal or trace, based solely on such computationally affordable matrix-vector multiplications, are well known and frequently used in signal inference, there is no stochastic estimate for its determinant. We introduce a probing method for the logarithm of a determinant of a linear operator. Our method rests upon a reformulation of the log-determinant by an integral representation and the transformation of the involved terms into stochastic expressions. This stochastic determinant determination enables large-size applications in Bayesian inference, in particular evidence calculations, model comparison, and posterior determination. PMID:26274302

  7. Mechanical autonomous stochastic heat engines

    NASA Astrophysics Data System (ADS)

    Serra-Garcia, Marc; Foehr, Andre; Moleron, Miguel; Lydon, Joseph; Chong, Christopher; Daraio, Chiara; . Team

    Stochastic heat engines extract work from the Brownian motion of a set of particles out of equilibrium. So far, experimental demonstrations of stochastic heat engines have required extreme operating conditions or nonautonomous external control systems. In this talk, we will present a simple, purely classical, autonomous stochastic heat engine that uses the well-known tension induced nonlinearity in a string. Our engine operates between two heat baths out of equilibrium, and transfers energy from the hot bath to a work reservoir. This energy transfer occurs even if the work reservoir is at a higher temperature than the hot reservoir. The talk will cover a theoretical investigation and experimental results on a macroscopic setup subject to external noise excitations. This system presents an opportunity for the study of non equilibrium thermodynamics and is an interesting candidate for innovative energy conversion devices.

  8. Principal axes for stochastic dynamics

    NASA Astrophysics Data System (ADS)

    Vasconcelos, V. V.; Raischel, F.; Haase, M.; Peinke, J.; Wächter, M.; Lind, P. G.; Kleinhans, D.

    2011-09-01

    We introduce a general procedure for directly ascertaining how many independent stochastic sources exist in a complex system modeled through a set of coupled Langevin equations of arbitrary dimension. The procedure is based on the computation of the eigenvalues and the corresponding eigenvectors of local diffusion matrices. We demonstrate our algorithm by applying it to two examples of systems showing Hopf bifurcation. We argue that computing the eigenvectors associated to the eigenvalues of the diffusion matrix at local mesh points in the phase space enables one to define vector fields of stochastic eigendirections. In particular, the eigenvector associated to the lowest eigenvalue defines the path of minimum stochastic forcing in phase space, and a transform to a new coordinate system aligned with the eigenvectors can increase the predictability of the system.

  9. Stochastic excitation of stellar oscillations

    NASA Astrophysics Data System (ADS)

    Samadi, Reza

    2001-05-01

    Since more than about thirty years, solar oscillations are thought to be excited stochastically by the turbulent motions in the solar convective zone. It is currently believed that oscillations of stars lower than 2 solar masses - which possess an upper convective zone - are excited stochastically by turbulent convection in their outer layers. Providing that accurate measurements of the oscillation amplitudes and damping rates are available it is possible to evaluate the power injected into the modes and thus - by comparison with the observations - to constrain current theories. A recent theoretical work (Samadi & Goupil, 2001; Samadi et al., 2001) supplements and reinforces the theory of stochastic excitation of star vibrations. This process was generalized to a global description of the turbulent state of their convective zone. The comparison between observation and theory, thus generalized, will allow to better know the turbulent spectrum of stars, and this in particular thanks to the COROT mission.

  10. Stochastic simulation of karst conduit networks

    NASA Astrophysics Data System (ADS)

    Pardo-Igúzquiza, Eulogio; Dowd, Peter A.; Xu, Chaoshui; Durán-Valsero, Juan José

    2012-01-01

    Karst aquifers have very high spatial heterogeneity. Essentially, they comprise a system of pipes (i.e., the network of conduits) superimposed on rock porosity and on a network of stratigraphic surfaces and fractures. This heterogeneity strongly influences the hydraulic behavior of the karst and it must be reproduced in any realistic numerical model of the karst system that is used as input to flow and transport modeling. However, the directly observed karst conduits are only a small part of the complete karst conduit system and knowledge of the complete conduit geometry and topology remains spatially limited and uncertain. Thus, there is a special interest in the stochastic simulation of networks of conduits that can be combined with fracture and rock porosity models to provide a realistic numerical model of the karst system. Furthermore, the simulated model may be of interest per se and other uses could be envisaged. The purpose of this paper is to present an efficient method for conditional and non-conditional stochastic simulation of karst conduit networks. The method comprises two stages: generation of conduit geometry and generation of topology. The approach adopted is a combination of a resampling method for generating conduit geometries from templates and a modified diffusion-limited aggregation method for generating the network topology. The authors show that the 3D karst conduit networks generated by the proposed method are statistically similar to observed karst conduit networks or to a hypothesized network model. The statistical similarity is in the sense of reproducing the tortuosity index of conduits, the fractal dimension of the network, the direction rose of directions, the Z-histogram and Ripley's K-function of the bifurcation points (which differs from a random allocation of those bifurcation points). The proposed method (1) is very flexible, (2) incorporates any experimental data (conditioning information) and (3) can easily be modified when implemented in a hydraulic inverse modeling procedure. Several synthetic examples are given to illustrate the methodology and real conduit network data are used to generate simulated networks that mimic real geometries and topology.

  11. Stochastic resonance in a nonlinear mechanical vibration isolation system

    NASA Astrophysics Data System (ADS)

    Lu, Zeqi; Chen, Li-Qun; Brennan, Michael J.; Yang, Tiejun; Ding, Hu; Liu, Zhigang

    2016-05-01

    This paper concerns the effect that a stochastic resonance can have on a vibration isolation system. Rather than reducing the transmitted force, it is shown that it is possible to significantly mask the component of the force transmitted though the isolator, when the system is excited harmonically. This can be achieved by adding a very low intensity of random noise to the harmonic excitation force. The nonlinear mechanical vibration isolation system used in the study consists of a vertical linear spring in parallel with two horizontal springs, which are configured so that the potential energy of the system has a double-well. Prior to the analytical and numerical study, an experiment to demonstrate stochastic resonance in a mechanical system is described.

  12. QB1 - Stochastic Gene Regulation

    SciTech Connect

    Munsky, Brian

    2012-07-23

    Summaries of this presentation are: (1) Stochastic fluctuations or 'noise' is present in the cell - Random motion and competition between reactants, Low copy, quantization of reactants, Upstream processes; (2) Fluctuations may be very important - Cell-to-cell variability, Cell fate decisions (switches), Signal amplification or damping, stochastic resonances; and (3) Some tools are available to mode these - Kinetic Monte Carlo simulations (SSA and variants), Moment approximation methods, Finite State Projection. We will see how modeling these reactions can tell us more about the underlying processes of gene regulation.

  13. Stochastic Optimization of Complex Systems

    SciTech Connect

    Birge, John R.

    2014-03-20

    This project focused on methodologies for the solution of stochastic optimization problems based on relaxation and penalty methods, Monte Carlo simulation, parallel processing, and inverse optimization. The main results of the project were the development of a convergent method for the solution of models that include expectation constraints as in equilibrium models, improvement of Monte Carlo convergence through the use of a new method of sample batch optimization, the development of new parallel processing methods for stochastic unit commitment models, and the development of improved methods in combination with parallel processing for incorporating automatic differentiation methods into optimization.

  14. Comments on optical stochastic cooling

    SciTech Connect

    K.Y. Ng, S.Y. Lee and Y.K. Zhang

    2002-10-08

    An important necessary condition for transverse phase space damping in the optical stochastic cooling with transit-time method is derived. The longitudinal and transverse damping dynamics for the optical stochastic cooling is studied. The authors also obtain an optimal laser focusing condition for laser-beam interaction in the correction undulator. The amplification factor and the output peak power of the laser amplifier are found to differ substantially from earlier publications. The required power is large for hadron colliders at very high energy.

  15. Stochastic models of chaotic systems

    SciTech Connect

    Leith, C.E.

    1995-09-01

    Nonlinear dynamical systems, although strictly deterministic, often exhibit chaotic behavior which appears to be random. The determination of the probabilistic properties of such systems is, in general, an open problem. Closure approximations for moment expansion methods have been unsatisfactory. More successful has been approximation on the dynamics level by the use of linear stochastic models that attempt to generate the probabilistic properties of the original nonlinear chaotic system as closely as possible. Examples are reviewed of this approach to simple nonlinear systems, to turbulence, and to large-eddy simulation. A stochastic model that simulates the transient energy spectrum of the global atmosphere is developed.

  16. Stochastic Cooling Developments at GSI

    SciTech Connect

    Nolden, F.; Beckert, K.; Beller, P.; Dolinskii, A.; Franzke, B.; Jandewerth, U.; Nesmiyan, I.; Peschke, C.; Petri, P.; Steck, M.; Caspers, F.; Moehl, D.; Thorndahl, L.

    2006-03-20

    Stochastic Cooling is presently used at the existing storage ring ESR as a first stage of cooling for secondary heavy ion beams. In the frame of the FAIR project at GSI, stochastic cooling is planned to play a major role for the preparation of high quality antiproton and rare isotope beams. The paper describes the existing ESR system, the first stage cooling system at the planned Collector Ring, and will also cover first steps toward the design of an antiproton collection system at the planned RESR ring.

  17. Theory, technology, and technique of stochastic cooling

    SciTech Connect

    Marriner, J.

    1993-10-01

    The theory and technological implementation of stochastic cooling is described. Theoretical and technological limitations are discussed. Data from existing stochastic cooling systems are shown to illustrate some useful techniques.

  18. Partial ASL extensions for stochastic programming.

    Energy Science and Technology Software Center (ESTSC)

    2010-03-31

    partially completed extensions for stochastic programming to the AMPL/solver interface library (ASL).modeling and experimenting with stochastic recourse problems. This software is not primarily for military applications

  19. Fund allocation using capacitated vehicle routing problem

    NASA Astrophysics Data System (ADS)

    Mamat, Nur Jumaadzan Zaleha; Jaaman, Saiful Hafizah; Ahmad, Rokiah Rozita; Darus, Maslina

    2014-09-01

    In investment fund allocation, it is unwise for an investor to distribute his fund into several assets simultaneously due to economic reasons. One solution is to allocate the fund into a particular asset at a time in a sequence that will either maximize returns or minimize risks depending on the investor's objective. The vehicle routing problem (VRP) provides an avenue to this issue. VRP answers the question on how to efficiently use the available fleet of vehicles to meet a given service demand, subjected to a set of operational requirements. This paper proposes an idea of using capacitated vehicle routing problem (CVRP) to optimize investment fund allocation by employing data of selected stocks in the FTSE Bursa Malaysia. Results suggest that CRVP can be applied to solve the issue of investment fund allocation and increase the investor's profit.

  20. Optimal dynamic bandwidth allocation for complex networks

    NASA Astrophysics Data System (ADS)

    Jiang, Zhong-Yuan; Liang, Man-Gui; Li, Qian; Guo, Dong-Chao

    2013-03-01

    Traffic capacity of one network strongly depends on the link’s bandwidth allocation strategy. In previous bandwidth allocation mechanisms, once one link’s bandwidth is allocated, it will be fixed throughout the overall traffic transmission process. However, the traffic load of every link changes from time to time. In this paper, with finite total bandwidth resource of the network, we propose to dynamically allocate the total bandwidth resource in which each link’s bandwidth is proportional to the queue length of the output buffer of the link per time step. With plenty of data packets in the network, the traffic handling ability of all links of the network achieves full utilization. The theoretical analysis and the extensive simulation results on complex networks are consistent. This work is valuable for network service providers to improve network performance or to do reasonable network design efficiently.

  1. Allocation of Resources in an Information System

    ERIC Educational Resources Information Center

    Bookstein, Abraham

    1974-01-01

    Considers the problem of allocation resources among various locations in an information system where phases of a process are carried out. Approach taken combines queueing theory and dynamic programming. (JB)

  2. Optimal Resource Allocation in Library Systems

    ERIC Educational Resources Information Center

    Rouse, William B.

    1975-01-01

    Queueing theory is used to model processes as either waiting or balking processes. The optimal allocation of resources to these processes is defined as that which maximizes the expected value of the decision-maker's utility function. (Author)

  3. 42 CFR 457.228 - Cost allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... or appropriate CHIP Agency will have an approved cost allocation plan on file with the Department in accordance with the requirements contained in subpart E of 45 CFR part 95. Subpart E also sets forth...

  4. 50 CFR 660.322 - Sablefish allocations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... are provided in § 660.385(a). (b) Between the limited entry and open access sectors. Sablefish is allocated between the limited entry and open access fisheries according to the procedure described in §...

  5. 45 CFR 1355.57 - Cost allocation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MAINTENANCE PAYMENTS, ADOPTION ASSISTANCE, AND CHILD AND FAMILY SERVICES GENERAL § 1355.57 Cost allocation. (a... care maintenance payments or adoption assistance payments may be made under the title IV-E plan....

  6. 45 CFR 1355.57 - Cost allocation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MAINTENANCE PAYMENTS, ADOPTION ASSISTANCE, AND CHILD AND FAMILY SERVICES GENERAL § 1355.57 Cost allocation. (a... care maintenance payments or adoption assistance payments may be made under the title IV-E plan....

  7. 45 CFR 1355.57 - Cost allocation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MAINTENANCE PAYMENTS, ADOPTION ASSISTANCE, AND CHILD AND FAMILY SERVICES GENERAL § 1355.57 Cost allocation. (a... care maintenance payments or adoption assistance payments may be made under the title IV-E plan....

  8. METHODS OF ANALYSIS FOR WASTE LOAD ALLOCATION

    EPA Science Inventory

    This research has addressed several unresolved questions concerning the allocation of allowable waste loads among multiple wastewater dischargers within a water quality limited stream segment. First, the traditional assumptions about critical design conditions for waste load allo...

  9. Study on the optimum power allocation algorithm based on adaptive allocation technology

    NASA Astrophysics Data System (ADS)

    Yang, Ming; Li, Zhendong; Di, Weiguo; Wang, Xiaoping

    2011-10-01

    According to the instantaneous estimate of sub-channel, adaptive allocation technology dynamically allocated number of bits transmitted and the transmit power, optimizing the overall performance of OFDM system. Having described the two basic principles of adaptive power allocation in the OFDM, and on the basis of this principle detailedly discussed three kinds of algorithms: adaptive bit allocation algorithm that is based on the capacity optimization, optimum power allocation algorithm based on the best bit error rate and the second-best power distribution algorithm. Through the system simulation using MATLAB software, characteristics and performance of three kinds of algorithms are analyzed and compared, which are in different channels and environments . Simulation results show that adaptive allocation technology can optimize the capacity of the system and bit error rate.

  10. Transport in a stochastic magnetic field

    SciTech Connect

    White, R.B.; Wu, Yanlin; Rax, J.M.

    1992-09-01

    Collisional heat transport in a stochastic magnetic field configuration is investigated. Well above stochastic threshold, a numerical solution of a Chirikov-Taylor model shows a short-time nonlocal regime, but at large time the Rechester-Rosenbluth effective diffusion is confirmed. Near stochastic threshold, subdiffusive behavior is observed for short mean free paths. The nature of this subdiffusive behavior is understood in terms of the spectrum of islands in the stochastic sea.

  11. The Hamiltonian Mechanics of Stochastic Acceleration

    SciTech Connect

    Burby, J. W.

    2013-07-17

    We show how to nd the physical Langevin equation describing the trajectories of particles un- dergoing collisionless stochastic acceleration. These stochastic di erential equations retain not only one-, but two-particle statistics, and inherit the Hamiltonian nature of the underlying microscopic equations. This opens the door to using stochastic variational integrators to perform simulations of stochastic interactions such as Fermi acceleration. We illustrate the theory by applying it to two example problems.

  12. Optimality versus stability in water resource allocation.

    PubMed

    Read, Laura; Madani, Kaveh; Inanloo, Bahareh

    2014-01-15

    Water allocation is a growing concern in a developing world where limited resources like fresh water are in greater demand by more parties. Negotiations over allocations often involve multiple groups with disparate social, economic, and political status and needs, who are seeking a management solution for a wide range of demands. Optimization techniques for identifying the Pareto-optimal (social planner solution) to multi-criteria multi-participant problems are commonly implemented, although often reaching agreement for this solution is difficult. In negotiations with multiple-decision makers, parties who base decisions on individual rationality may find the social planner solution to be unfair, thus creating a need to evaluate the willingness to cooperate and practicality of a cooperative allocation solution, i.e., the solution's stability. This paper suggests seeking solutions for multi-participant resource allocation problems through an economics-based power index allocation method. This method can inform on allocation schemes that quantify a party's willingness to participate in a negotiation rather than opt for no agreement. Through comparison of the suggested method with a range of distance-based multi-criteria decision making rules, namely, least squares, MAXIMIN, MINIMAX, and compromise programming, this paper shows that optimality and stability can produce different allocation solutions. The mismatch between the socially-optimal alternative and the most stable alternative can potentially result in parties leaving the negotiation as they may be too dissatisfied with their resource share. This finding has important policy implications as it justifies why stakeholders may not accept the socially optimal solution in practice, and underlies the necessity of considering stability where it may be more appropriate to give up an unstable Pareto-optimal solution for an inferior stable one. Authors suggest assessing the stability of an allocation solution as an additional component to an analysis that seeks to distribute water in a negotiated process. PMID:24412983

  13. Stochasticity, succession, and environmental perturbations in a fluidic ecosystem

    PubMed Central

    Zhou, Jizhong; Deng, Ye; Zhang, Ping; Xue, Kai; Liang, Yuting; Van Nostrand, Joy D.; Yang, Yunfeng; He, Zhili; Wu, Liyou; Stahl, David A.; Hazen, Terry C.; Tiedje, James M.; Arkin, Adam P.

    2014-01-01

    Unraveling the drivers of community structure and succession in response to environmental change is a central goal in ecology. Although the mechanisms shaping community structure have been intensively examined, those controlling ecological succession remain elusive. To understand the relative importance of stochastic and deterministic processes in mediating microbial community succession, a unique framework composed of four different cases was developed for fluidic and nonfluidic ecosystems. The framework was then tested for one fluidic ecosystem: a groundwater system perturbed by adding emulsified vegetable oil (EVO) for uranium immobilization. Our results revealed that groundwater microbial community diverged substantially away from the initial community after EVO amendment and eventually converged to a new community state, which was closely clustered with its initial state. However, their composition and structure were significantly different from each other. Null model analysis indicated that both deterministic and stochastic processes played important roles in controlling the assembly and succession of the groundwater microbial community, but their relative importance was time dependent. Additionally, consistent with the proposed conceptual framework but contradictory to conventional wisdom, the community succession responding to EVO amendment was primarily controlled by stochastic rather than deterministic processes. During the middle phase of the succession, the roles of stochastic processes in controlling community composition increased substantially, ranging from 81.3% to 92.0%. Finally, there are limited successional studies available to support different cases in the conceptual framework, but further well-replicated explicit time-series experiments are needed to understand the relative importance of deterministic and stochastic processes in controlling community succession. PMID:24550501

  14. Allocation Games: Addressing the Ill-Posed Nature of Allocation in Life-Cycle Inventories.

    PubMed

    Hanes, Rebecca J; Cruze, Nathan B; Goel, Prem K; Bakshi, Bhavik R

    2015-07-01

    Allocation is required when a life cycle contains multi-functional processes. One approach to allocation is to partition the embodied resources in proportion to a criterion, such as product mass or cost. Many practitioners apply multiple partitioning criteria to avoid choosing one arbitrarily. However, life cycle results from different allocation methods frequently contradict each other, making it difficult or impossible for the practitioner to draw any meaningful conclusions from the study. Using the matrix notation for life-cycle inventory data, we show that an inventory that requires allocation leads to an ill-posed problem: an inventory based on allocation is one of an infinite number of inventories that are highly dependent upon allocation methods. This insight is applied to comparative life-cycle assessment (LCA), in which products with the same function but different life cycles are compared. Recently, there have been several studies that applied multiple allocation methods and found that different products were preferred under different methods. We develop the Comprehensive Allocation Investigation Strategy (CAIS) to examine any given inventory under all possible allocation decisions, enabling us to detect comparisons that are not robust to allocation, even when the comparison appears robust under conventional partitioning methods. While CAIS does not solve the ill-posed problem, it provides a systematic way to parametrize and examine the effects of partitioning allocation. The practical usefulness of this approach is demonstrated with two case studies. The first compares ethanol produced from corn stover hydrolysis, corn stover gasification, and corn grain fermentation. This comparison was not robust to allocation. The second case study compares 1,3-propanediol (PDO) produced from fossil fuels and from biomass, which was found to be a robust comparison. PMID:26061700

  15. Allocation of authority in European health policy.

    PubMed

    Adolph, Christopher; Greer, Scott L; Massard da Fonseca, Elize

    2012-11-01

    Although many study the effects of different allocations of health policy authority, few ask why countries assign responsibility over different policies as they do. We test two broad theories: fiscal federalism, which predicts rational governments will concentrate information-intensive operations at lower levels, and redistributive and regulatory functions at higher levels; and "politicized federalism", which suggests a combination of systematic and historically idiosyncratic political variables interfere with efficient allocation of authority. Drawing on the WHO Health in Transition country profiles, we present new data on the allocation of responsibility for key health care policy tasks (implementation, provision, finance, regulation, and framework legislation) and policy areas (primary, secondary and tertiary care, public health and pharmaceuticals) in the 27 EU member states and Switzerland. We use a Bayesian multinomial mixed logit model to analyze how different countries arrive at different allocations of authority over each task and area of health policy, and find the allocation of powers broadly follows fiscal federalism. Responsibility for pharmaceuticals, framework legislation, and most finance lodges at the highest levels of government, acute and primary care in the regions, and provision at the local and regional levels. Where allocation does not follow fiscal federalism, it appears to reflect ethnic divisions, the population of states and regions, the presence of mountainous terrain, and the timing of region creation. PMID:22858423

  16. Advances in liver transplantation allocation systems.

    PubMed

    Schilsky, Michael L; Moini, Maryam

    2016-03-14

    With the growing number of patients in need of liver transplantation, there is a need for adopting new and modifying existing allocation policies that prioritize patients for liver transplantation. Policy should ensure fair allocation that is reproducible and strongly predictive of best pre and post transplant outcomes while taking into account the natural history of the potential recipients liver disease and its complications. There is wide acceptance for allocation policies based on urgency in which the sickest patients on the waiting list with the highest risk of mortality receive priority. Model for end-stage liver disease and Child-Turcotte-Pugh scoring system, the two most universally applicable systems are used in urgency-based prioritization. However, other factors must be considered to achieve optimal allocation. Factors affecting pre-transplant patient survival and the quality of the donor organ also affect outcome. The optimal system should have allocation prioritization that accounts for both urgency and transplant outcome. We reviewed past and current liver allocation systems with the aim of generating further discussion about improvement of current policies. PMID:26973389

  17. Advances in liver transplantation allocation systems

    PubMed Central

    Schilsky, Michael L; Moini, Maryam

    2016-01-01

    With the growing number of patients in need of liver transplantation, there is a need for adopting new and modifying existing allocation policies that prioritize patients for liver transplantation. Policy should ensure fair allocation that is reproducible and strongly predictive of best pre and post transplant outcomes while taking into account the natural history of the potential recipients liver disease and its complications. There is wide acceptance for allocation policies based on urgency in which the sickest patients on the waiting list with the highest risk of mortality receive priority. Model for end-stage liver disease and Child-Turcotte-Pugh scoring system, the two most universally applicable systems are used in urgency-based prioritization. However, other factors must be considered to achieve optimal allocation. Factors affecting pre-transplant patient survival and the quality of the donor organ also affect outcome. The optimal system should have allocation prioritization that accounts for both urgency and transplant outcome. We reviewed past and current liver allocation systems with the aim of generating further discussion about improvement of current policies. PMID:26973389

  18. Stochastically forced zonal flows

    NASA Astrophysics Data System (ADS)

    Srinivasan, Kaushik

    This thesis investigates the dynamics of multiple zonal jets, that spontaneously emerge on the barotropic beta-plane, driven by a homogenous and rapidly decorrelating forcing and damped by bottom drag. Decomposing the barotropic vorticity equation into the zonal-mean and eddy equations, and neglecting the eddy-eddy interactions, defines the quasi-linear (QL) system. Numerical solution of the QL system shows zonal jets with length scales comparable to jets obtained by solving the nonlinear (NL) system. Starting with the QL system, one can construct a deterministic equation for the evolution of the two-point single-time correlation function of the vorticity, from which one can obtain the Reynolds stress that drives the zonal mean flow. This deterministic system has an exact nonlinear solution, which is a homogenous eddy field with no jets. When the forcing is also isotropic in space, we characterize the linear stability of this jetless solution by calculating the critical stability curve in the parameter space and successfully comparing this analytic result with numerical solutions of the QL system. But the critical drag required for the onset of NL zonostrophic instability is up to a factor of six smaller than that for QL zonostrophic instability. The constraint of isotropic forcing is then relaxed and spatially anisotropic forcing is used to drive the jets. Meridionally drifting jets are observed whenever the forcing breaks an additional symmetry that we refer to as mirror, or reflexional symmetry. The magnitude of drift speed in our results shows a strong variation with both mu and beta: while the drift speed decreases almost linearly with decreasing mu, it actually increases as beta decreases. Similar drifting jets are also observed in QL, with the same direction (i.e. northward or southward) and similar magnitude as NL jet-drift. Starting from the laminar solution, and assuming a mean-flow that varies slowly with reference to the scale of the eddies, we obtain an approximate equation for the vorticity correlation function that is then solved perturbatively. The Reynolds stress of the pertubative solution can then be expressed as a function of the mean-flow and its y-derivatives. In particular, it is shown that as long as the forcing breaks mirror-symmetry, the Reynolds stress has a wave-like term, as a result of which the mean-flow is governed by a dispersive wave equation. In a separate study, Reynolds stress induced by an anisotropically forced unbounded Couette flow with uniform shear gamma, on a beta-plane, is calculated in conjunction with the eddy diffusivity of a co-evolving passive tracer. The flow is damped by linear drag on a time scale mu--1. The stochastic forcing is controlled by a parameter alpha, that characterizes whether eddies are elongated along the zonal direction (alpha < 0), the meridional direction (alpha > 0) or are isotropic (alpha = 0). The Reynolds stress varies linearly with alpha and non-linearly and non-monotonically with gamma; but the Reynolds stress is independent of beta. For positive values of alpha, the Reynolds stress displays an "anti-frictional" effect (energy is transferred from the eddies to the mean flow) and a frictional effect for negative values of alpha. With gamma = beta =0, the meridional tracer eddy diffusivity is v'2/(2mu), where v' is the meridional eddy velocity. In general, beta and gamma suppress the diffusivity below v'2/(2mu).

  19. Tuscaloosa redevelopment adding reserves

    SciTech Connect

    Petzet, G.A.

    1995-12-04

    Amoco reports positive initial results from a redevelopment program in the deep, geologically complex Upper Cretaceous Tuscaloosa trend of Southeast Louisiana. The program, heavy on the synergy of geoscience disciplines, has resulted in eight deep completions without a failure. They include six wells in Port Hudson field that averaged 10 MMcfd/well of gas and 1,300 b/d well of condensate. Geologic complexity meant 3D data alone couldn`t carry the program, but none of the wells at Port Hudson could have been drilled based on Amoco`s pre-3D geologic knowledge. Success required a synthesis of 3D with geology ad engineering expertise. Geologic predictions derived from the advance geoscience work helped cut drilling costs, and a seismic service company alliance has brought down 3D seismic costs. The paper discusses the well completions, the geoscience program, and cost savings.

  20. Bubbling geometries for AdS2× S2

    NASA Astrophysics Data System (ADS)

    Lunin, Oleg

    2015-10-01

    We construct BPS geometries describing normalizable excitations of AdS2×S2. All regular horizon-free solutions are parameterized by two harmonic functions in R 3 with sources along closed curves. This local structure is reminiscent of the "bubbling solutions" for the other AdS p ×S q cases, however, due to peculiar asymptotic properties of AdS2, one copy of R 3 does not cover the entire space, and we discuss the procedure for analytic continuation, which leads to a nontrivial topological structure of the new geometries. We also study supersymmetric brane probes on the new geometries, which represent the AdS2×S2 counterparts of the giant gravitons.

  1. The stochastic dance of early HIV infection

    NASA Astrophysics Data System (ADS)

    Merrill, Stephen J.

    2005-12-01

    The stochastic nature of early HIV infection is described in a series of models, each of which captures aspects of the dance of HIV during the early stages of infection. It is to this highly variable target that the immune response must respond. The adaptability of the various components of the immune response is an important aspect of the system's operation, as the nature of the pathogens that the response will be required to respond to and the order in which those responses must be made cannot be known beforehand. As HIV infection has direct influence over cells responsible for the immune response, the dance predicts that the immune response will be also in a variable state of readiness and capability for this task of adaptation. The description of the stochastic dance of HIV here will use the tools of stochastic models, and for the most part, simulation. The justification for this approach is that the early stages and the development of HIV diversity require that the model to be able to describe both individual sample path and patient-to-patient variability. In addition, as early viral dynamics are best described using branching processes, the explosive growth of these models both predicts high variability and rapid response of HIV to changes in system parameters.In this paper, a basic viral growth model based on a time dependent continuous-time branching process is used to describe the growth of HIV infected cells in the macrophage and lymphocyte populations. Immigration from the reservoir population is added to the basic model to describe the incubation time distribution. This distribution is deduced directly from the modeling assumptions and the model of viral growth. A system of two branching processes, one in the infected macrophage population and one in the infected lymphocyte population is used to provide a description of the relationship between the development of HIV diversity as it relates to tropism (host cell preference). The role of the immune response to HIV and HIV infected cells is used to describe the movement of the infection from a few infected macrophages to a disease of infected CD4+ T lymphocytes.

  2. Stochastic Reinforcement Benefits Skill Acquisition

    ERIC Educational Resources Information Center

    Dayan, Eran; Averbeck, Bruno B.; Richmond, Barry J.; Cohen, Leonardo G.

    2014-01-01

    Learning complex skills is driven by reinforcement, which facilitates both online within-session gains and retention of the acquired skills. Yet, in ecologically relevant situations, skills are often acquired when mapping between actions and rewarding outcomes is unknown to the learning agent, resulting in reinforcement schedules of a stochastic

  3. Stochastic Resonance and Information Processing

    NASA Astrophysics Data System (ADS)

    Nicolis, C.

    2014-12-01

    A dynamical system giving rise to multiple steady states and subjected to noise and a periodic forcing is analyzed from the standpoint of information theory. It is shown that stochastic resonance has a clearcut signature on information entropy, information transfer and other related quantities characterizing information transduction within the system.

  4. Stochastic tunnels in evolutionary dynamics.

    PubMed Central

    Iwasa, Yoh; Michor, Franziska; Nowak, Martin A

    2004-01-01

    We study a situation that arises in the somatic evolution of cancer. Consider a finite population of replicating cells and a sequence of mutations: type 0 can mutate to type 1, which can mutate to type 2. There is no back mutation. We start with a homogeneous population of type 0. Mutants of type 1 emerge and either become extinct or reach fixation. In both cases, they can generate type 2, which also can become extinct or reach fixation. If mutation rates are small compared to the inverse of the population size, then the stochastic dynamics can be described by transitions between homogeneous populations. A "stochastic tunnel" arises, when the population moves from all 0 to all 2 without ever being all 1. We calculate the exact rate of stochastic tunneling for the case when type 1 is as fit as type 0 or less fit. Type 2 has the highest fitness. We discuss implications for the elimination of tumor suppressor genes and the activation of genetic instability. Although our theory is developed for cancer genetics, stochastic tunnels are general phenomena that could arise in many circumstances. PMID:15082570

  5. Numerical simulations in stochastic mechanics

    NASA Astrophysics Data System (ADS)

    McClendon, Marvin; Rabitz, Herschel

    1988-05-01

    The stochastic differential equation of Nelson's stochastic mechanics is integrated numerically for several simple quantum systems. The calculations are performed with use of Helfand and Greenside's method and pseudorandom numbers. The resulting trajectories are analyzed both individually and collectively to yield insight into momentum, uncertainty principles, interference, tunneling, quantum chaos, and common models of diatomic molecules from the stochastic quantization point of view. In addition to confirming Shucker's momentum theorem, these simulations illustrate, within the context of stochastic mechanics, the position-momentum and time-energy uncertainty relations, the two-slit diffraction pattern, exponential decay of an unstable system, and the greater degree of anticorrelation in a valence-bond model as compared with a molecular-orbital model of H2. The attempt to find exponential divergence of initially nearby trajectories, potentially useful as a criterion for quantum chaos, in a periodically forced oscillator is inconclusive. A way of computing excited energies from the ground-state motion is presented. In all of these studies the use of particle trajectories allows a more insightful interpretation of physical phenomena than is possible within traditional wave mechanics.

  6. Stochastic-field cavitation model

    SciTech Connect

    Dumond, J.; Magagnato, F.; Class, A.

    2013-07-15

    Nonlinear phenomena can often be well described using probability density functions (pdf) and pdf transport models. Traditionally, the simulation of pdf transport requires Monte-Carlo codes based on Lagrangian “particles” or prescribed pdf assumptions including binning techniques. Recently, in the field of combustion, a novel formulation called the stochastic-field method solving pdf transport based on Eulerian fields has been proposed which eliminates the necessity to mix Eulerian and Lagrangian techniques or prescribed pdf assumptions. In the present work, for the first time the stochastic-field method is applied to multi-phase flow and, in particular, to cavitating flow. To validate the proposed stochastic-field cavitation model, two applications are considered. First, sheet cavitation is simulated in a Venturi-type nozzle. The second application is an innovative fluidic diode which exhibits coolant flashing. Agreement with experimental results is obtained for both applications with a fixed set of model constants. The stochastic-field cavitation model captures the wide range of pdf shapes present at different locations.

  7. Stochastic resonance on a circle

    SciTech Connect

    Wiesenfeld, K. ); Pierson, D.; Pantazelou, E.; Dames, C.; Moss, F. )

    1994-04-04

    We describe a new realization of stochastic resonance, applicable to a broad class of systems, based on an underlying excitable dynamics with deterministic reinjection. A simple but general theory of such single-trigger'' systems is compared with analog simulations of the Fitzhugh-Nagumo model, as well as experimental data obtained from stimulated sensory neurons in the crayfish.

  8. Stochastic cooling: recent theoretical directions

    SciTech Connect

    Bisognano, J.

    1983-03-01

    A kinetic-equation derivation of the stochastic-cooling Fokker-Planck equation of correlation is introduced to describe both the Schottky spectrum and signal suppression. Generalizations to nonlinear gain and coupling between degrees of freedom are presented. Analysis of bunch beam cooling is included.

  9. Universality in Stochastic Exponential Growth

    NASA Astrophysics Data System (ADS)

    Iyer-Biswas, Srividya; Crooks, Gavin E.; Scherer, Norbert F.; Dinner, Aaron R.

    2014-07-01

    Recent imaging data for single bacterial cells reveal that their mean sizes grow exponentially in time and that their size distributions collapse to a single curve when rescaled by their means. An analogous result holds for the division-time distributions. A model is needed to delineate the minimal requirements for these scaling behaviors. We formulate a microscopic theory of stochastic exponential growth as a Master Equation that accounts for these observations, in contrast to existing quantitative models of stochastic exponential growth (e.g., the Black-Scholes equation or geometric Brownian motion). Our model, the stochastic Hinshelwood cycle (SHC), is an autocatalytic reaction cycle in which each molecular species catalyzes the production of the next. By finding exact analytical solutions to the SHC and the corresponding first passage time problem, we uncover universal signatures of fluctuations in exponential growth and division. The model makes minimal assumptions, and we describe how more complex reaction networks can reduce to such a cycle. We thus expect similar scalings to be discovered in stochastic processes resulting in exponential growth that appear in diverse contexts such as cosmology, finance, technology, and population growth.

  10. Stochastic-field cavitation model

    NASA Astrophysics Data System (ADS)

    Dumond, J.; Magagnato, F.; Class, A.

    2013-07-01

    Nonlinear phenomena can often be well described using probability density functions (pdf) and pdf transport models. Traditionally, the simulation of pdf transport requires Monte-Carlo codes based on Lagrangian "particles" or prescribed pdf assumptions including binning techniques. Recently, in the field of combustion, a novel formulation called the stochastic-field method solving pdf transport based on Eulerian fields has been proposed which eliminates the necessity to mix Eulerian and Lagrangian techniques or prescribed pdf assumptions. In the present work, for the first time the stochastic-field method is applied to multi-phase flow and, in particular, to cavitating flow. To validate the proposed stochastic-field cavitation model, two applications are considered. First, sheet cavitation is simulated in a Venturi-type nozzle. The second application is an innovative fluidic diode which exhibits coolant flashing. Agreement with experimental results is obtained for both applications with a fixed set of model constants. The stochastic-field cavitation model captures the wide range of pdf shapes present at different locations.

  11. [Value-Added--Adding Economic Value in the Food Industry].

    ERIC Educational Resources Information Center

    Welch, Mary A., Ed.

    1989-01-01

    This booklet focuses on the economic concept of "value added" to goods and services. A student activity worksheet illustrates how the steps involved in processing food are examples of the concept of value added. The booklet further links food processing to the idea of value added to the Gross National Product (GNP). Discussion questions, a student…

  12. Algorithmic advances in stochastic programming

    SciTech Connect

    Morton, D.P.

    1993-07-01

    Practical planning problems with deterministic forecasts of inherently uncertain parameters often yield unsatisfactory solutions. Stochastic programming formulations allow uncertain parameters to be modeled as random variables with known distributions, but the size of the resulting mathematical programs can be formidable. Decomposition-based algorithms take advantage of special structure and provide an attractive approach to such problems. We consider two classes of decomposition-based stochastic programming algorithms. The first type of algorithm addresses problems with a ``manageable`` number of scenarios. The second class incorporates Monte Carlo sampling within a decomposition algorithm. We develop and empirically study an enhanced Benders decomposition algorithm for solving multistage stochastic linear programs within a prespecified tolerance. The enhancements include warm start basis selection, preliminary cut generation, the multicut procedure, and decision tree traversing strategies. Computational results are presented for a collection of ``real-world`` multistage stochastic hydroelectric scheduling problems. Recently, there has been an increased focus on decomposition-based algorithms that use sampling within the optimization framework. These approaches hold much promise for solving stochastic programs with many scenarios. A critical component of such algorithms is a stopping criterion to ensure the quality of the solution. With this as motivation, we develop a stopping rule theory for algorithms in which bounds on the optimal objective function value are estimated by sampling. Rules are provided for selecting sample sizes and terminating the algorithm under which asymptotic validity of confidence interval statements for the quality of the proposed solution can be verified. Issues associated with the application of this theory to two sampling-based algorithms are considered, and preliminary empirical coverage results are presented.

  13. Stochastic resonance in visual sensitivity.

    PubMed

    Kundu, Ajanta; Sarkar, Sandip

    2015-04-01

    It is well known from psychophysical studies that stochastic resonance, in its simplest threshold paradigm, can be used as a tool to measure the detection sensitivity to fine details in noise contaminated stimuli. In the present manuscript, we report simulation studies conducted in the similar threshold paradigm of stochastic resonance. We have estimated the contrast sensitivity in detecting noisy sine-wave stimuli, with varying area and spatial frequency, as a function of noise strength. In all the cases, the measured sensitivity attained a peak at intermediate noise strength, which indicate the occurrence of stochastic resonance. The peak sensitivity exhibited a strong dependence on area and spatial frequency of the stimulus. We show that the peak contrast sensitivity varies with spatial frequency in a nonmonotonic fashion and the qualitative nature of the sensitivity variation is in good agreement with human contrast sensitivity function. We also demonstrate that the peak sensitivity first increases and then saturates with increasing area, and this result is in line with the results of psychophysical experiments. Additionally, we also show that critical area, denoting the saturation of contrast sensitivity, decreases with spatial frequency and the associated maximum contrast sensitivity varies with spatial frequency in a manner that is consistent with the results of psychophysical experiments. In all the studies, the sensitivities were elevated via a nonlinear filtering operation called stochastic resonance. Because of this nonlinear effect, it was not guaranteed that the sensitivities, estimated at each frequency, would be in agreement with the corresponding results of psychophysical experiments; on the contrary, close agreements were observed between our results and the findings of psychophysical investigations. These observations indicate the utility of stochastic resonance in human vision and suggest that this paradigm can be useful in psychophysical studies. PMID:25398687

  14. 12 CFR 28.52 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Allocated transfer risk reserve. 28.52 Section... ACTIVITIES International Lending Supervision § 28.52 Allocated transfer risk reserve. (a) Establishment of allocated transfer risk reserve. A banking institution shall establish an allocated transfer risk...

  15. 12 CFR 347.303 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 4 2011-01-01 2011-01-01 false Allocated transfer risk reserve. 347.303... GENERAL POLICY INTERNATIONAL BANKING International Lending § 347.303 Allocated transfer risk reserve. (a) Establishment of Allocated Transfer Risk Reserve. A banking institution shall establish an allocated...

  16. 12 CFR 347.303 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Allocated transfer risk reserve. 347.303... GENERAL POLICY INTERNATIONAL BANKING International Lending § 347.303 Allocated transfer risk reserve. (a) Establishment of Allocated Transfer Risk Reserve. A banking institution shall establish an allocated...

  17. 12 CFR 347.303 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 5 2012-01-01 2012-01-01 false Allocated transfer risk reserve. 347.303... GENERAL POLICY INTERNATIONAL BANKING International Lending § 347.303 Allocated transfer risk reserve. (a) Establishment of Allocated Transfer Risk Reserve. A banking institution shall establish an allocated...

  18. 12 CFR 28.52 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Allocated transfer risk reserve. 28.52 Section... ACTIVITIES International Lending Supervision § 28.52 Allocated transfer risk reserve. (a) Establishment of allocated transfer risk reserve. A banking institution shall establish an allocated transfer risk...

  19. 12 CFR 347.303 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Allocated transfer risk reserve. 347.303... GENERAL POLICY INTERNATIONAL BANKING International Lending § 347.303 Allocated transfer risk reserve. (a) Establishment of Allocated Transfer Risk Reserve. A banking institution shall establish an allocated...

  20. 12 CFR 28.52 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Allocated transfer risk reserve. 28.52 Section... ACTIVITIES International Lending Supervision § 28.52 Allocated transfer risk reserve. (a) Establishment of allocated transfer risk reserve. A banking institution shall establish an allocated transfer risk...

  1. 49 CFR 198.13 - Grant allocation formula.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Grant allocation formula. 198.13 Section 198.13... PIPELINE SAFETY PROGRAMS Grant Allocation § 198.13 Grant allocation formula. (a) Beginning in calendar year... state agency comments on any proposed changes to the allocation formula. (f) Grants are limited to...

  2. 47 CFR 2.106 - Table of Frequency Allocations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Table of Frequency Allocations. 2.106 Section 2.106 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Allocation, Assignment, and Use of Radio Frequencies § 2.106 Table of Frequency Allocations. Editorial...

  3. 10 CFR 217.54 - Elements of an allocation order.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Allocations System regulation (10 CFR part 217), which is part of the Federal Priorities and Allocations System”; and (e) A current copy of the Energy Priorities and Allocations System regulation (10 CFR part... 10 Energy 3 2013-01-01 2013-01-01 false Elements of an allocation order. 217.54 Section...

  4. 10 CFR 217.54 - Elements of an allocation order.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Allocations System regulation (10 CFR part 217), which is part of the Federal Priorities and Allocations System”; and (e) A current copy of the Energy Priorities and Allocations System regulation (10 CFR part... 10 Energy 3 2014-01-01 2014-01-01 false Elements of an allocation order. 217.54 Section...

  5. 49 CFR 33.54 - Elements of an allocation order.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Transportation Priorities and Allocations System regulation (49 CFR Part 33)”; and (e) A current copy of the Transportation Priorities and Allocations System regulation (49 CFR Part 33) as of the date of the allocation... 49 Transportation 1 2014-10-01 2014-10-01 false Elements of an allocation order. 33.54 Section...

  6. 49 CFR 33.54 - Elements of an allocation order.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Transportation Priorities and Allocations System regulation (49 CFR Part 33)”; and (e) A current copy of the Transportation Priorities and Allocations System regulation (49 CFR Part 33) as of the date of the allocation... 49 Transportation 1 2012-10-01 2012-10-01 false Elements of an allocation order. 33.54 Section...

  7. 10 CFR 217.54 - Elements of an allocation order.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Allocations System regulation (10 CFR part 217), which is part of the Federal Priorities and Allocations System”; and (e) A current copy of the Energy Priorities and Allocations System regulation (10 CFR part... 10 Energy 3 2012-01-01 2012-01-01 false Elements of an allocation order. 217.54 Section...

  8. 49 CFR 33.54 - Elements of an allocation order.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Transportation Priorities and Allocations System regulation (49 CFR Part 33)”; and (e) A current copy of the Transportation Priorities and Allocations System regulation (49 CFR Part 33) as of the date of the allocation... 49 Transportation 1 2013-10-01 2013-10-01 false Elements of an allocation order. 33.54 Section...

  9. 12 CFR 347.303 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Allocated transfer risk reserve. 347.303... GENERAL POLICY INTERNATIONAL BANKING International Lending § 347.303 Allocated transfer risk reserve. (a) Establishment of Allocated Transfer Risk Reserve. A banking institution shall establish an allocated...

  10. 12 CFR 28.52 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Allocated transfer risk reserve. 28.52 Section... ACTIVITIES International Lending Supervision § 28.52 Allocated transfer risk reserve. (a) Establishment of allocated transfer risk reserve. A banking institution shall establish an allocated transfer risk...

  11. 47 CFR 32.22 - Comprehensive interperiod tax allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Comprehensive interperiod tax allocation. 32.22... interperiod tax allocation. (a) Companies shall apply interperiod tax allocation (tax normalization) to all... purposes. Furthermore, companies shall also apply interperiod tax allocation if any item or group...

  12. 26 CFR 1.141-6 - Allocation and accounting rules.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 2 2011-04-01 2011-04-01 false Allocation and accounting rules. 1.141-6 Section... Allocation and accounting rules. (a) Allocation of proceeds to expenditures. For purposes of §§ 1.141-1.... Thus, allocations generally may be made using any reasonable, consistently applied accounting...

  13. 26 CFR 1.141-6 - Allocation and accounting rules.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Allocation and accounting rules. 1.141-6 Section... Allocation and accounting rules. (a) Allocation of proceeds to expenditures. For purposes of §§ 1.141-1.... Thus, allocations generally may be made using any reasonable, consistently applied accounting...

  14. 26 CFR 1.141-6 - Allocation and accounting rules.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 2 2012-04-01 2012-04-01 false Allocation and accounting rules. 1.141-6 Section... Allocation and accounting rules. (a) Allocation of proceeds to expenditures. For purposes of §§ 1.141-1.... Thus, allocations generally may be made using any reasonable, consistently applied accounting...

  15. 26 CFR 1.141-6 - Allocation and accounting rules.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Allocation and accounting rules. 1.141-6 Section... Allocation and accounting rules. (a) Allocation of proceeds to expenditures. For purposes of §§ 1.141-1.... Thus, allocations generally may be made using any reasonable, consistently applied accounting...

  16. The evolution of parental care in stochastic environments.

    PubMed

    Bonsall, M B; Klug, H

    2011-03-01

    Parental care is of fundamental importance to understanding reproductive strategies and allocation decisions. Here, we explore how parental care strategies evolve in variable environments. Using a set of life-history trait trade-offs, we explore the relative costs and benefits of parental care in stochastic environments. Specifically, we consider the cases in which environmental variability results in varying adult death rates, egg death rates, reproductive rate and carrying capacity. Using a measure of fitness appropriate for stochastic environments, we find that parental care has the potential to evolve over a wide range of life-history characteristics when the environment is variable. A variable environment that affects adult or egg death rates can either increase or decrease the fitness of care relative to that in a constant environment, depending on the specific costs of care. Variability that affects carrying capacity or adult reproductive rate has negligible effects on the fitness associated with care. Increasing parental care across different life-history stages can increase fitness gains in variable environments. Costly investment in care is expected to affect the overall fitness benefits, the fitness optimum and rate of evolution of parental care. In general, we find that environmental variability, the life-history traits affected by such variability and the specific costs of care interact to determine whether care will be favoured in a variable environment and what levels of care will be selected. PMID:21261769

  17. Assessing marginal water values in multipurpose multireservoir systems via stochastic programming

    NASA Astrophysics Data System (ADS)

    Tilmant, A.; Pinte, D.; Goor, Q.

    2008-12-01

    The International Conference on Water and the Environment held in Dublin in 1992 emphasized the need to consider water as an economic good. Since water markets are usually absent or ineffective, the value of water cannot be directly derived from market activities but must rather be assessed through shadow prices. Economists have developed various valuation techniques to determine the economic value of water, especially to handle allocation issues involving environmental water uses. Most of the nonmarket valuation studies reported in the literature focus on long-run policy problems, such as permanent (re)allocations of water, and assume that the water availability is given. When dealing with short-run allocation problems, water managers are facing complex spatial and temporal trade-offs and must therefore be able to track site and time changes in water values across different hydrologic conditions, especially in arid and semiarid areas where the availability of water is a limiting and stochastic factor. This paper presents a stochastic programming approach for assessing the statistical distribution of marginal water values in multipurpose multireservoir systems where hydropower generation and irrigation crop production are the main economic activities depending on water. In the absence of a water market, the Lagrange multipliers correspond to shadow prices, and the marginal water values are the Lagrange multipliers associated with the mass balance equations of the reservoirs. The methodology is illustrated with a cascade of hydroelectric-irrigation reservoirs in the Euphrates river basin in Turkey and Syria.

  18. Stochastic spur gear dynamics by numerical path integration

    NASA Astrophysics Data System (ADS)

    Naess, A.; Kolnes, F. E.; Mo, E.

    2007-05-01

    In this paper the method of numerical path integration is applied to investigate the dynamics of a model of a pair of meshing spur gears. Our approach is based on the observation that the dynamics of a nonlinear mechanical system excited by a deterministic loading process can, to a large extent, be characterized by the response obtained by adding a small white noise to the loading. By this, the response can be expressed as a Markov diffusion process, which makes available the powerful toolbox of stochastic analysis, in particular the path integration method.

  19. An Analysis and Allocation System for Library Collections Budgets: The Comprehensive Allocation Process (CAP)

    ERIC Educational Resources Information Center

    Lyons, Lucy Eleonore; Blosser, John

    2012-01-01

    The "Comprehensive Allocation Process" (CAP) is a reproducible decision-making structure for the allocation of new collections funds, for the reallocation of funds within stagnant budgets, and for budget cuts in the face of reduced funding levels. This system was designed to overcome common shortcomings of current methods. Its philosophical…

  20. An Analysis and Allocation System for Library Collections Budgets: The Comprehensive Allocation Process (CAP)

    ERIC Educational Resources Information Center

    Lyons, Lucy Eleonore; Blosser, John

    2012-01-01

    The "Comprehensive Allocation Process" (CAP) is a reproducible decision-making structure for the allocation of new collections funds, for the reallocation of funds within stagnant budgets, and for budget cuts in the face of reduced funding levels. This system was designed to overcome common shortcomings of current methods. Its philosophical

  1. AdS spacetimes from wrapped D3-branes

    NASA Astrophysics Data System (ADS)

    Gauntlett, Jerome P.; MacConamhna, Oisín A. P.

    2007-12-01

    We derive a geometrical characterization of a large class of AdS3 and AdS2 supersymmetric spacetimes in type IIB supergravity with non-vanishing five-form flux using G-structures. These are obtained as special cases of a class of supersymmetric spacetimes with an {{\\bb R}}^{1,1} or {{\\bb R}} (time) factor that are associated with D3 branes wrapping calibrated two or three cycles, respectively, in manifolds with SU(2), SU(3), SU(4) and G2 holonomy. We show how two explicit AdS solutions, previously constructed in gauged supergravity, satisfy our more general G-structure conditions. For each explicit solution, we also derive a special holonomy metric which, although singular, has an appropriate calibrated cycle. After analytic continuation, some of the classes of AdS spacetimes give rise to known classes of BPS bubble solutions with {{\\bb R}}\\times {\\it SO}(4)\\times {\\it SO}(4), {{\\bb R}}\\times {\\it SO}(4)\\times U(1) and {{\\bb R}}\\times {\\it SO}(4) symmetry. These have 1/2, 1/4 and 1/8 supersymmetry, respectively. We present a new class of 1/8 BPS geometries with {{\\bb R}}\\times {\\it SU}(2) symmetry, obtained by analytic continuation of the class of AdS spacetimes associated with D3-brane wrapped on associative three cycles.

  2. Supergravity at the boundary of AdS supergravity

    SciTech Connect

    Amsel, Aaron J.; Compere, Geoffrey

    2009-04-15

    We give a general analysis of AdS boundary conditions for spin-3/2 Rarita-Schwinger fields and investigate boundary conditions preserving supersymmetry for a graviton multiplet in AdS{sub 4}. Linear Rarita-Schwinger fields in AdS{sub d} are shown to admit mixed Dirichlet-Neumann boundary conditions when their mass is in the range 0{<=}|m|<1/2l{sub AdS}. We also demonstrate that mixed boundary conditions are allowed for larger masses when the inner product is 'renormalized' accordingly with the action. We then use the results obtained for |m|=1/l{sub AdS} to explore supersymmetric boundary conditions for N=1 AdS{sub 4} supergravity in which the metric and Rarita-Schwinger fields are fluctuating at the boundary. We classify boundary conditions that preserve boundary supersymmetry or superconformal symmetry. Under the AdS/CFT dictionary, Neumann boundary conditions in d=4 supergravity correspond to gauging the superconformal group of the three-dimensional CFT describing M2-branes, while N=1 supersymmetric mixed boundary conditions couple the CFT to N=1 superconformal topologically massive gravity.

  3. Supergravity at the boundary of AdS supergravity

    NASA Astrophysics Data System (ADS)

    Amsel, Aaron J.; Compre, Geoffrey

    2009-04-01

    We give a general analysis of AdS boundary conditions for spin-3/2 Rarita-Schwinger fields and investigate boundary conditions preserving supersymmetry for a graviton multiplet in AdS4. Linear Rarita-Schwinger fields in AdSd are shown to admit mixed Dirichlet-Neumann boundary conditions when their mass is in the range 0?|m|<1/2lAdS. We also demonstrate that mixed boundary conditions are allowed for larger masses when the inner product is renormalized accordingly with the action. We then use the results obtained for |m|=1/lAdS to explore supersymmetric boundary conditions for N=1 AdS4 supergravity in which the metric and Rarita-Schwinger fields are fluctuating at the boundary. We classify boundary conditions that preserve boundary supersymmetry or superconformal symmetry. Under the AdS/CFT dictionary, Neumann boundary conditions in d=4 supergravity correspond to gauging the superconformal group of the three-dimensional CFT describing M2-branes, while N=1 supersymmetric mixed boundary conditions couple the CFT to N=1 superconformal topologically massive gravity.

  4. Value-Added Measures for Schools in England: Looking inside the "Black Box" of Complex Metrics

    ERIC Educational Resources Information Center

    Kelly, Anthony; Downey, Christopher

    2010-01-01

    Value-added measures can be used to allocate funding to schools, to identify those institutions in need of special attention and to underpin government guidance on targets. In England, there has been a tendency to include in these measures an ever-greater number of contextualising variables and to develop ever-more complex models that encourage…

  5. Value-Added Measures for Schools in England: Looking inside the "Black Box" of Complex Metrics

    ERIC Educational Resources Information Center

    Kelly, Anthony; Downey, Christopher

    2010-01-01

    Value-added measures can be used to allocate funding to schools, to identify those institutions in need of special attention and to underpin government guidance on targets. In England, there has been a tendency to include in these measures an ever-greater number of contextualising variables and to develop ever-more complex models that encourage

  6. Optimal fund assignment and allocation models for pipe repair maintenance in leaky water distribution networks

    NASA Astrophysics Data System (ADS)

    Bach, Nguyen Luong; Fujiwara, Okitsugu; Luong, Huynh Trung

    2000-05-01

    In pipe repair maintenance operations for leaky water distribution networks in cities, it is usually the practice that whenever pipe leaks are detected, repair actions are undertaken until the funds assigned are exhausted. The allocation of limited repair funds to different pipe sections is normally done without careful quantitative analysis but according to an intuitive rule, whereby the section of the larger leak volume receives the larger share of funds. This paper proposes a new modeling approach to determine optimal repair fund allocation to different sections of a city. A basic periodic-review stochastic demand inventory model is first applied to ascertain the optimal funds to be assigned to a city under an assumption of no fund limitation. The model is then extended to determine the optimal allocation of the limited funds to different sections of a city. The models minimize the expected total system cost composed of repair cost, storage cost (of spare parts and materials), and penalty cost for water loss due to lack of funds. Numerical experiments are then conducted to illustrate the applicability of the proposed models, and the characteristics of the optimal solutions with regard to parameter variations are investigated. Data used in the numerical example are taken from actual data of the secondary network of Ho Chi Minh City in Vietnam.

  7. Biomass Resource Allocation among Competing End Uses

    SciTech Connect

    Newes, E.; Bush, B.; Inman, D.; Lin, Y.; Mai, T.; Martinez, A.; Mulcahy, D.; Short, W.; Simpkins, T.; Uriarte, C.; Peck, C.

    2012-05-01

    The Biomass Scenario Model (BSM) is a system dynamics model developed by the U.S. Department of Energy as a tool to better understand the interaction of complex policies and their potential effects on the biofuels industry in the United States. However, it does not currently have the capability to account for allocation of biomass resources among the various end uses, which limits its utilization in analysis of policies that target biomass uses outside the biofuels industry. This report provides a more holistic understanding of the dynamics surrounding the allocation of biomass among uses that include traditional use, wood pellet exports, bio-based products and bioproducts, biopower, and biofuels by (1) highlighting the methods used in existing models' treatments of competition for biomass resources; (2) identifying coverage and gaps in industry data regarding the competing end uses; and (3) exploring options for developing models of biomass allocation that could be integrated with the BSM to actively exchange and incorporate relevant information.

  8. Task mapping for non-contiguous allocations.

    SciTech Connect

    Leung, Vitus Joseph; Bunde, David P.; Ebbers, Johnathan; Price, Nicholas W.; Swank, Matthew; Feer, Stefan P.; Rhodes, Zachary D.

    2013-02-01

    This paper examines task mapping algorithms for non-contiguously allocated parallel jobs. Several studies have shown that task placement affects job running time for both contiguously and non-contiguously allocated jobs. Traditionally, work on task mapping either uses a very general model where the job has an arbitrary communication pattern or assumes that jobs are allocated contiguously, making them completely isolated from each other. A middle ground between these two cases is the mapping problem for non-contiguous jobs having a specific communication pattern. We propose several task mapping algorithms for jobs with a stencil communication pattern and evaluate them using experiments and simulations. Our strategies improve the running time of a MiniApp by as much as 30% over a baseline strategy. Furthermore, this improvement increases markedly with the job size, demonstrating the importance of task mapping as systems grow toward exascale.

  9. New massive gravity and AdS(4) counterterms.

    PubMed

    Jatkar, Dileep P; Sinha, Aninda

    2011-04-29

    We show that the recently proposed Dirac-Born-Infeld extension of new massive gravity emerges naturally as a counterterm in four-dimensional anti-de Sitter space (AdS(4)). The resulting on-shell Euclidean action is independent of the cutoff at zero temperature. We also find that the same choice of counterterm gives the usual area law for the AdS(4) Schwarzschild black hole entropy in a cutoff-independent manner. The parameter values of the resulting counterterm action correspond to a c=0 theory in the context of the duality between AdS(3) gravity and two-dimensional conformal field theory. We rewrite this theory in terms of the gauge field that is used to recast 3D gravity as a Chern-Simons theory. PMID:21635026

  10. Null warped AdS in higher spin gravity

    NASA Astrophysics Data System (ADS)

    Breunhölder, Veronika; Gary, Mirah; Grumiller, Daniel; Prohazka, Stefan

    2015-12-01

    We equip three-dimensional spin-3 gravity in the principal embedding with a new set of boundary conditions that we call "asymptotically null warped AdS". We find a chiral copy of the Polyakov-Bershadsky algebra as asymptotic symmetry algebra, reminiscent of the situation in topologically massive gravity with strict null warped AdS boundary conditions. We prove the invertibility of the map between zuvielbein and metric variables and construct a global gauge transformation to half of AdS spin-3 gravity in the diagonal embedding. This explains why the theory is chiral and why the Polyakov-Bershadsky algebra arises. We then introduce chemical potentials, derive the entropy, free energy, and the holographic response functions, and conclude with a discussion.

  11. Stochastic stability of traffic maps

    NASA Astrophysics Data System (ADS)

    Blank, Michael

    2012-12-01

    We study the ergodic properties of a family of traffic maps acting in the space of bi-infinite sequences of real numbers. The corresponding dynamics mimics the motion of vehicles in a simple traffic flow, which explains the name. Using connections to topological Markov chains we obtain nontrivial invariant measures, prove their stochastic stability and calculate the topological entropy. Technically these results in the deterministic setting are related to the construction of measures of maximal entropy via measures uniformly distributed on periodic points of a given period, while in the random setting we construct (spatially) Markov invariant measures directly. In distinction to conventional results the limiting measures in the non-lattice case are non-ergodic. The average velocity of individual ‘vehicles’ as a function of their density and its stochastic stability is studied as well.

  12. Stochastic methods in population forecasting.

    PubMed

    Alho, J M

    1990-12-01

    "This paper presents a stochastic version of the demographic cohort-component method of forecasting future population. In this model the sizes of future age-sex groups are non-linear functions of random future vital rates. An approximation to their joint distribution can be obtained using linear approximations or simulation. A stochastic formulation points to the need for new empirical work on both the autocorrelations and the cross-correlations of the vital rates. Problems of forecasting declining mortality and fluctuating fertility are contrasted. A volatility measure for fertility is presented. The model can be used to calculate approximate prediction intervals for births using data from deterministic cohort-component forecasts. The paper compares the use of expert opinion in mortality forecasting with simple extrapolation techniques to see how useful each approach has been in the past. Data from the United States suggest that expert opinion may have caused systematic bias in the forecasts." PMID:12285033

  13. Stochastic thermodynamics with information reservoirs

    NASA Astrophysics Data System (ADS)

    Barato, Andre C.; Seifert, Udo

    2014-10-01

    We generalize stochastic thermodynamics to include information reservoirs. Such information reservoirs, which can be modeled as a sequence of bits, modify the second law. For example, work extraction from a system in contact with a single heat bath becomes possible if the system also interacts with an information reservoir. We obtain an inequality, and the corresponding fluctuation theorem, generalizing the standard entropy production of stochastic thermodynamics. From this inequality we can derive an information processing entropy production, which gives the second law in the presence of information reservoirs. We also develop a systematic linear response theory for information processing machines. For a unicyclic machine powered by an information reservoir, the efficiency at maximum power can deviate from the standard value of 1 /2 . For the case where energy is consumed to erase the tape, the efficiency at maximum erasure rate is found to be 1 /2 .

  14. Stochastic models for haptic texture

    NASA Astrophysics Data System (ADS)

    Fritz, Jason P.; Barner, Kenneth E.

    1996-12-01

    Recent research in haptic systems has begun to focus on the generation of textures to enhance haptic simulations. Synthetic texture generation can be achieved through the use of stochastic modeling techniques to produce random and pseudo-random texture patterns. These models are based on techniques used in computer graphics texture generation and textured image analysis and modeling. The goal for this project is to synthesize haptic textures that are perceptually distinct. Two new rendering methods for haptic texturing are presented for implementation of stochastic based texture models using a 3 DOF point interaction haptic interface. The synthesized textures can be used in a myriad of applications, including haptic data visualization for blind individuals and overall enhancement of haptic simulations.

  15. Stochastic dynamics of cholera epidemics

    NASA Astrophysics Data System (ADS)

    Azaele, Sandro; Maritan, Amos; Bertuzzo, Enrico; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

    2010-05-01

    We describe the predictions of an analytically tractable stochastic model for cholera epidemics following a single initial outbreak. The exact model relies on a set of assumptions that may restrict the generality of the approach and yet provides a realm of powerful tools and results. Without resorting to the depletion of susceptible individuals, as usually assumed in deterministic susceptible-infected-recovered models, we show that a simple stochastic equation for the number of ill individuals provides a mechanism for the decay of the epidemics occurring on the typical time scale of seasonality. The model is shown to provide a reasonably accurate description of the empirical data of the 2000/2001 cholera epidemic which took place in the Kwa Zulu-Natal Province, South Africa, with possibly notable epidemiological implications.

  16. Delay stabilizes stochastic motion of bumps in layered neural fields

    NASA Astrophysics Data System (ADS)

    Kilpatrick, Zachary P.

    2015-03-01

    We study the effects of propagation delays on the stochastic dynamics of bumps in neural fields with multiple layers. In the absence of noise, each layer supports a stationary bump. Using linear stability analysis, we show that delayed coupling between layers causes translating perturbations of the bumps to decay in the noise-free system. Adding noise to the system causes bumps to wander as a random walk. However, coupling between layers can reduce the variability of this stochastic motion by canceling noise that perturbs bumps in opposite directions. Delays in interlaminar coupling can further reduce variability, since they couple bump positions to states from the past. We demonstrate these relationships by deriving an asymptotic approximation for the effective motion of bumps. This yields a stochastic delay-differential equation where each delayed term arises from an interlaminar coupling. The impact of delays is well approximated by using a small delay expansion, which allows us to compute the effective diffusion in bumps' positions, accurately matching results from numerical simulations.

  17. Stochastic background of atmospheric cascades

    SciTech Connect

    Wilk, G. ); Wlodarczyk, Z. )

    1993-06-15

    Fluctuations in the atmospheric cascades developing during the propagation of very high energy cosmic rays through the atmosphere are investigated using stochastic branching model of pure birth process with immigration. In particular, we show that the multiplicity distributions of secondaries emerging from gamma families are much narrower than those resulting from hadronic families. We argue that the strong intermittent like behaviour found recently in atmospheric families results from the fluctuations in the cascades themselves and are insensitive to the details of elementary interactions.

  18. Stochastic cooling technology at Fermilab

    NASA Astrophysics Data System (ADS)

    Pasquinelli, Ralph J.

    2004-10-01

    The first antiproton cooling systems were installed and commissioned at Fermilab in 1984-1985. In the interim period, there have been several major upgrades, system improvements, and complete reincarnation of cooling systems. This paper will present some of the technology that was pioneered at Fermilab to implement stochastic cooling systems in both the Antiproton Source and Recycler accelerators. Current performance data will also be presented.

  19. Stochastic models for relativistic diffusion

    SciTech Connect

    Baeumer, Boris; Meerschaert, Mark M.; Naber, Mark

    2010-07-15

    The diffusion equation is related to the Schroedinger equation by analytic continuation. The formula E{sup 2}=p{sup 2}c{sup 2}+m{sup 2}c{sup 4} leads to a relativistic Schroedinger equation, and analytic continuation yields a relativistic diffusion equation that involves fractional calculus. This paper develops stochastic models for relativistic diffusion and equivalent differential equations with no fractional derivatives. Connections to anomalous diffusion are also discussed, along with alternative models.

  20. All static black holes in AdS3

    NASA Astrophysics Data System (ADS)

    Haddad, Nidal

    2016-03-01

    In this work we find the general static vacuum solution of three-dimensional gravity with negative cosmological constant. Even though all solutions are locally diffeomorphic to pure AdS3 , solutions that differ globally from the latter space exist. New solutions with black holes on the AdS3 boundary are found in both global and Poincare coordinates. In the Poincare coordinates such solutions are known as black funnels and black droplets. The black funnel provided by our general static metric is dual to the Hartle-Hawking state in the 1 +1 boundary theory.

  1. Stochastic mechanics of reciprocal diffusions

    NASA Astrophysics Data System (ADS)

    Levy, Bernard C.; Krener, Arthur J.

    1996-02-01

    The dynamics and kinematics of reciprocal diffusions were examined in a previous paper [J. Math. Phys. 34, 1846 (1993)], where it was shown that reciprocal diffusions admit a chain of conservation laws, which close after the first two laws for two disjoint subclasses of reciprocal diffusions, the Markov and quantum diffusions. For the case of quantum diffusions, the conservation laws are equivalent to Schrödinger's equation. The Markov diffusions were employed by Schrödinger [Sitzungsber. Preuss. Akad. Wiss. Phys. Math Kl. 144 (1931); Ann. Inst. H. Poincaré 2, 269 (1932)], Nelson [Dynamical Theories of Brownian Motion (Princeton University, Princeton, NJ, 1967); Quantum Fluctuations (Princeton University, Princeton, NJ, 1985)], and other researchers to develop stochastic formulations of quantum mechanics, called stochastic mechanics. We propose here an alternative version of stochastic mechanics based on quantum diffusions. A procedure is presented for constructing the quantum diffusion associated to a given wave function. It is shown that quantum diffusions satisfy the uncertainty principle, and have a locality property, whereby given two dynamically uncoupled but statistically correlated particles, the marginal statistics of each particle depend only on the local fields to which the particle is subjected. However, like Wigner's joint probability distribution for the position and momentum of a particle, the finite joint probability densities of quantum diffusions may take negative values.

  2. Turbulence, Spontaneous Stochasticity and Climate

    NASA Astrophysics Data System (ADS)

    Eyink, Gregory

    Turbulence is well-recognized as important in the physics of climate. Turbulent mixing plays a crucial role in the global ocean circulation. Turbulence also provides a natural source of variability, which bedevils our ability to predict climate. I shall review here a recently discovered turbulence phenomenon, called ``spontaneous stochasticity'', which makes classical dynamical systems as intrinsically random as quantum mechanics. Turbulent dissipation and mixing of scalars (passive or active) is now understood to require Lagrangian spontaneous stochasticity, which can be expressed by an exact ``fluctuation-dissipation relation'' for scalar turbulence (joint work with Theo Drivas). Path-integral methods such as developed for quantum mechanics become necessary to the description. There can also be Eulerian spontaneous stochasticity of the flow fields themselves, which is intimately related to the work of Kraichnan and Leith on unpredictability of turbulent flows. This leads to problems similar to those encountered in quantum field theory. To quantify uncertainty in forecasts (or hindcasts), we can borrow from quantum field-theory the concept of ``effective actions'', which characterize climate averages by a variational principle and variances by functional derivatives. I discuss some work with Tom Haine (JHU) and Santha Akella (NASA-Goddard) to make this a practical predictive tool. More ambitious application of the effective action is possible using Rayleigh-Ritz schemes.

  3. Stochastic resonance in neuron models

    SciTech Connect

    Longtin, A. Los Alamos National Lab., NM )

    1993-01-01

    Periodically stimulated sensory neurons typically exhibit a kind of statistical phase locking' to the stimulus: they tend to fire at a preferred phase of the stimulus cycle, but not at every cycle. Hence, the histogram of interspike intervals (ISIH), ie., of times between successive firings, is multimodal for these neurons, with peaks centered at integer multiples of the driving period. A particular kind of residence time histogram for a large class of noisy bistable systems has recently been shown to exhibit the major features of the neural data. In the present paper, the authors show that an excitable cell model, the Fitzhugh-Nagumo equations, also reproduces these features when driven by additive periodic and stochastic forces. This model exhibits its own brand of stochastic resonance as the peaks of the ISIH successively go through a maximum when the noise intensity is increased. Further, the presence of a noise-induced limit cycle introduces a third time scale in the problem. This limit cycle is found to modify qualitatively the phase-locking picture, e.g., by suppressing certain peaks in the ISIH. Finally, the role of noise and possibly of stochastic resonance (SR) in the neural encoding of sensory information is discussed. 29 refs., 10 figs.

  4. Internal stochastic resonance under two-parameter modulation in intercellular calcium ion oscillations

    NASA Astrophysics Data System (ADS)

    Li, Ya Ping; Li, Qian Shu

    2004-05-01

    Internal stochastic resonance (ISR) in a model of intercellular calcium ion oscillations is investigated under the modulation of two parameters, viz., degree of extracellular stimulation (β) and leak rate (kf). ISR can occur when either β or kf is subjected to a noise. Internal stochastic biresonance (ISBR) can occur when noise is added to the two parameters simultaneously. The distance to the bifurcation point is found to be able to enhance or suppress the ISBR, and to affect the number of peaks of ISR.

  5. Internal stochastic resonance under two-parameter modulation in intercellular calcium ion oscillations.

    PubMed

    Li, Ya Ping; Li, Qian Shu

    2004-05-01

    Internal stochastic resonance (ISR) in a model of intercellular calcium ion oscillations is investigated under the modulation of two parameters, viz., degree of extracellular stimulation (beta) and leak rate (k(f)). ISR can occur when either beta or k(f) is subjected to a noise. Internal stochastic biresonance (ISBR) can occur when noise is added to the two parameters simultaneously. The distance to the bifurcation point is found to be able to enhance or suppress the ISBR, and to affect the number of peaks of ISR. PMID:15267806

  6. Abrupt Convergence for Stochastic Small Perturbations of One Dimensional Dynamical Systems

    NASA Astrophysics Data System (ADS)

    Barrera, G.; Jara, M.

    2016-02-01

    We study the cut-off phenomenon for a family of stochastic small perturbations of a one dimensional dynamical system. We will focus in a semiflow of a deterministic differential equation which is perturbed by adding to the dynamics a white noise of small variance. Under suitable hypothesis on the potential we will prove that the family of perturbed stochastic differential equations present a profile cut-off phenomenon with respect to the total variation distance. We also prove a local cut-off phenomenon in a neighborhood of the local minima (metastable states) of multi-well potential.

  7. Abrupt Convergence for Stochastic Small Perturbations of One Dimensional Dynamical Systems

    NASA Astrophysics Data System (ADS)

    Barrera, G.; Jara, M.

    2016-04-01

    We study the cut-off phenomenon for a family of stochastic small perturbations of a one dimensional dynamical system. We will focus in a semiflow of a deterministic differential equation which is perturbed by adding to the dynamics a white noise of small variance. Under suitable hypothesis on the potential we will prove that the family of perturbed stochastic differential equations present a profile cut-off phenomenon with respect to the total variation distance. We also prove a local cut-off phenomenon in a neighborhood of the local minima (metastable states) of multi-well potential.

  8. The forecaster's added value

    NASA Astrophysics Data System (ADS)

    Turco, M.; Milelli, M.

    2009-09-01

    To the authors' knowledge there are relatively few studies that try to answer this topic: "Are humans able to add value to computer-generated forecasts and warnings ?". Moreover, the answers are not always positive. In particular some postprocessing method is competitive or superior to human forecast (see for instance Baars et al., 2005, Charba et al., 2002, Doswell C., 2003, Roebber et al., 1996, Sanders F., 1986). Within the alert system of ARPA Piemonte it is possible to study in an objective manner if the human forecaster is able to add value with respect to computer-generated forecasts. Every day the meteorology group of the Centro Funzionale of Regione Piemonte produces the HQPF (Human QPF) in terms of an areal average for each of the 13 regional warning areas, which have been created according to meteo-hydrological criteria. This allows the decision makers to produce an evaluation of the expected effects by comparing these HQPFs with predefined rainfall thresholds. Another important ingredient in this study is the very dense non-GTS network of rain gauges available that makes possible a high resolution verification. In this context the most useful verification approach is the measure of the QPF and HQPF skills by first converting precipitation expressed as continuous amounts into ‘‘exceedance'' categories (yes-no statements indicating whether precipitation equals or exceeds selected thresholds) and then computing the performances for each threshold. In particular in this work we compare the performances of the latest three years of QPF derived from two meteorological models COSMO-I7 (the Italian version of the COSMO Model, a mesoscale model developed in the framework of the COSMO Consortium) and IFS (the ECMWF global model) with the HQPF. In this analysis it is possible to introduce the hypothesis test developed by Hamill (1999), in which a confidence interval is calculated with the bootstrap method in order to establish the real difference between the skill scores of two competitive forecast. It is important to underline that the conclusions refer to the analysis of the Piemonte operational alert system, so they cannot be directly taken as universally true. But we think that some of the main lessons that can be derived from this study could be useful for the meteorological community. In details, the main conclusions are the following: - despite the overall improvement in global scale and the fact that the resolution of the limited area models has increased considerably over recent years, the QPF produced by the meteorological models involved in this study has not improved enough to allow its direct use, that is, the subjective HQPF continues to offer the best performance; - in the forecast process, the step where humans have the largest added value with respect to mathematical models, is the communication. In fact the human characterisation and communication of the forecast uncertainty to end users cannot be replaced by any computer code; - eventually, although there is no novelty in this study, we would like to show that the correct application of appropriated statistical techniques permits a better definition and quantification of the errors and, mostly important, allows a correct (unbiased) communication between forecasters and decision makers.

  9. AESS: Accelerated Exact Stochastic Simulation

    NASA Astrophysics Data System (ADS)

    Jenkins, David D.; Peterson, Gregory D.

    2011-12-01

    The Stochastic Simulation Algorithm (SSA) developed by Gillespie provides a powerful mechanism for exploring the behavior of chemical systems with small species populations or with important noise contributions. Gene circuit simulations for systems biology commonly employ the SSA method, as do ecological applications. This algorithm tends to be computationally expensive, so researchers seek an efficient implementation of SSA. In this program package, the Accelerated Exact Stochastic Simulation Algorithm (AESS) contains optimized implementations of Gillespie's SSA that improve the performance of individual simulation runs or ensembles of simulations used for sweeping parameters or to provide statistically significant results. Program summaryProgram title: AESS Catalogue identifier: AEJW_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJW_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: University of Tennessee copyright agreement No. of lines in distributed program, including test data, etc.: 10 861 No. of bytes in distributed program, including test data, etc.: 394 631 Distribution format: tar.gz Programming language: C for processors, CUDA for NVIDIA GPUs Computer: Developed and tested on various x86 computers and NVIDIA C1060 Tesla and GTX 480 Fermi GPUs. The system targets x86 workstations, optionally with multicore processors or NVIDIA GPUs as accelerators. Operating system: Tested under Ubuntu Linux OS and CentOS 5.5 Linux OS Classification: 3, 16.12 Nature of problem: Simulation of chemical systems, particularly with low species populations, can be accurately performed using Gillespie's method of stochastic simulation. Numerous variations on the original stochastic simulation algorithm have been developed, including approaches that produce results with statistics that exactly match the chemical master equation (CME) as well as other approaches that approximate the CME. Solution method: The Accelerated Exact Stochastic Simulation (AESS) tool provides implementations of a wide variety of popular variations on the Gillespie method. Users can select the specific algorithm considered most appropriate. Comparisons between the methods and with other available implementations indicate that AESS provides the fastest known implementation of Gillespie's method for a variety of test models. Users may wish to execute ensembles of simulations to sweep parameters or to obtain better statistical results, so AESS supports acceleration of ensembles of simulation using parallel processing with MPI, SSE vector units on x86 processors, and/or using NVIDIA GPUs with CUDA.

  10. A randomized pilot study of stochastic vibration therapy in spinocerebellar ataxia.

    PubMed

    Kaut, O; Jacobi, H; Coch, C; Prochnicki, A; Minnerop, M; Klockgether, T; Wüllner, U

    2014-04-01

    Whole body vibration (WBV) is a biomechanical treatment used widely in professional sports and rehabilitation. We examined the effect of stochastic WBV on ataxia in spinocerebellar ataxia types 1, 2, 3, and 6 (SCA 1, 2, 3 and 6) in a single-center double-blind sham-controlled study. Stochastic WBV was applied on four sequent days, each treatment consisting of five stimulus trains of 60-s duration at a frequency of 6.5 Hz and 60-s resting time between stimuli (n = 17). Patients allocated to the sham group received the same treatment with 1 Hz (n = 15). All patients were rated at baseline and after the last treatment using clinical scores (SARA, SCAFI, and INAS). After treatment, we found significant improvements of gait, posture, and speed of speech in the verum group while limb kinetics and ataxia of speech did not respond. Stochastic WBV might act on proprioceptive mechanisms and could also stimulate non-cerebellar/compensatory mechanisms. But at present, the involved cellular mechanism and the presumed neuronal loops cannot be deciphered. Thus, future work is needed to understand the mechanisms of whole body vibration. Finally, the use of stochastic WBV could provide a supplementation to treat ataxia in SCA and can be combined with physiotherapeutical motor training. PMID:24197754

  11. Mystery cloud of AD 536

    NASA Technical Reports Server (NTRS)

    Stothers, R. B.

    1984-01-01

    The possible cause of the densest and most persistent dry fog on record, which was observed in Europe and the Middle East during AD 536 and 537, is discussed. The fog's long duration toward the south and the high sulfuric acid signal detected in Greenland in ice cores dated around AD 540 support the theory that the fog was due to the explosion of the Rabaul volcano, the occurrence of which has been dated at about AD 540 by the radiocarbon method.

  12. Long time behaviour of a stochastic nanoparticle

    NASA Astrophysics Data System (ADS)

    Étoré, Pierre; Labbé, Stéphane; Lelong, Jérôme

    2014-09-01

    In this article, we are interested in the behaviour of a single ferromagnetic mono-domain particle submitted to an external field with a stochastic perturbation. This model is the first step toward the mathematical understanding of thermal effects on a ferromagnet. In a first part, we present the stochastic model and prove that the associated stochastic differential equation is well defined. The second part is dedicated to the study of the long time behaviour of the magnetic moment and in the third part we prove that the stochastic perturbation induces a non-reversibility phenomenon. Last, we illustrate these results through numerical simulations of our stochastic model. The main results presented in this article are on the one hand the rate of convergence of the magnetization toward the unique stable equilibrium of the deterministic model and on the other hand a sharp estimate of the hysteresis phenomenon induced by the stochastic perturbation (remember that with no perturbation, the magnetic moment remains constant).

  13. Generalized spectral decomposition for stochastic nonlinear problems

    SciTech Connect

    Nouy, Anthony Le Maitre, Olivier P.

    2009-01-10

    We present an extension of the generalized spectral decomposition method for the resolution of nonlinear stochastic problems. The method consists in the construction of a reduced basis approximation of the Galerkin solution and is independent of the stochastic discretization selected (polynomial chaos, stochastic multi-element or multi-wavelets). Two algorithms are proposed for the sequential construction of the successive generalized spectral modes. They involve decoupled resolutions of a series of deterministic and low-dimensional stochastic problems. Compared to the classical Galerkin method, the algorithms allow for significant computational savings and require minor adaptations of the deterministic codes. The methodology is detailed and tested on two model problems, the one-dimensional steady viscous Burgers equation and a two-dimensional nonlinear diffusion problem. These examples demonstrate the effectiveness of the proposed algorithms which exhibit convergence rates with the number of modes essentially dependent on the spectrum of the stochastic solution but independent of the dimension of the stochastic approximation space.

  14. Stochastic ordering properties and optimal routing control for a class of finite capacity queueing systems

    NASA Technical Reports Server (NTRS)

    Towsley, Don; Sparaggis, Panayotis D.; Cassandras, Christos G.

    1990-01-01

    The problem of routing jobs to parallel queues with identical exponential servers and unequal finite buffer capacities is considered. Stochastic ordering and weak majorization properties on critical performance measures are established by means of event-driven inductions. In particular, it is shown that the intuitive 'join the shortest non-full queue' (SNQ) policy is optimal with respect to an overall function that accounts for holding and blocking costs. Moreover, the buffer allocation problem is solved by proving the intuitive result that, for a fixed total buffer capacity, the optimal allocation scheme is the one in which the difference between the maximum and minimum queue capacities is minimized, i.e., becomes either 0 or 1.

  15. Supersymmetric AdS5 solutions of massive IIA supergravity

    NASA Astrophysics Data System (ADS)

    Apruzzi, Fabio; Fazzi, Marco; Passias, Achilleas; Tomasiello, Alessandro

    2015-06-01

    Motivated by a recently found class of AdS7 solutions, we classify AdS5 solutions in massive IIA, finding infinitely many new analytical examples. We reduce the general problem to a set of PDEs, determining the local internal metric, which is a fibration over a surface. Under a certain simplifying assumption, we are then able to analytically solve the PDEs and give a complete list of all solutions. Among these, one class is new and regular. These spaces can be related to the AdS7 solutions via a simple universal map for the metric, dilaton and fluxes. The natural interpretation of this map is that the dual CFT6 and CFT4 are related by twisted compactification on a Riemann surface Σ g . The ratio of their free energy coefficients is proportional to the Euler characteristic of Σ g . As a byproduct, we also find the analytic expression for the AdS7 solutions, which were previously known only numerically. We determine the free energy for simple examples: it is a simple cubic function of the flux integers.

  16. AdS Branes from Partial Breaking of Superconformal Symmetries

    SciTech Connect

    Ivanov, E.A.

    2005-10-01

    It is shown how the static-gauge world-volume superfield actions of diverse superbranes on the AdS{sub d+1} superbackgrounds can be systematically derived from nonlinear realizations of the appropriate AdS supersymmetries. The latter are treated as superconformal symmetries of flat Minkowski superspaces of the bosonic dimension d. Examples include the N = 1 AdS{sub 4} supermembrane, which is associated with the 1/2 partial breaking of the OSp(1|4) supersymmetry down to the N = 1, d = 3 Poincare supersymmetry, and the T-duality related L3-brane on AdS{sub 5} and scalar 3-brane on AdS{sub 5} x S{sup 1}, which are associated with two different patterns of 1/2 breaking of the SU(2, 2|1) supersymmetry. Another (closely related) topic is the AdS/CFT equivalence transformation. It maps the world-volume actions of the codimension-one AdS{sub d+1} (super)branes onto the actions of the appropriate Minkowski (super)conformal field theories in the dimension d.

  17. 10 CFR 455.31 - Allocation formulas.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... § 455.31 Allocation formulas. (a) Financial assistance for conducting technical assistance programs for... of eligible States; (4) SP is the population of the State; (5) SC is the sum of the State's heating and cooling degree days; and (6) NPC is the summation of the (SP)(SC) numerators for all States....

  18. Rumination and Impaired Resource Allocation in Depression

    PubMed Central

    Levens, Sara M.; Muhtadie, Luma; Gotlib, Ian H.

    2010-01-01

    Depression is characterized by a range of cognitive deficits that theorists posit are due to the resource capturing properties of rumination. The present study was designed to examine the relation between rumination and resource allocation in depression. Twenty-five depressed and 25 nondepressed participants completed a modified dual-task version of the recency-probes task, which assesses the controlled allocation of cognitive resources by comparing performance across low- and high-interference conditions. In low-interference conditions, participants performed either the recency-probes task or a tracking task, which required participants to track specific stimuli across trials (i.e., no dual-task interference). In the high-interference condition, participants performed both the recency-probes task and the tracking task, which required the controlled allocation of resources to resolve dual-task interference. Depressed participants performed significantly worse than did their nondepressed counterparts in only the high-interference condition; performance of the 2 groups was comparable in the low-interference conditions. Furthermore, the degree to which depressed participants were impaired in the high-interference condition was correlated .74 with rumination. These findings suggest that an association between rumination and impairments in resource allocation underlies the cognitive difficulties experienced by depressed individuals. PMID:19899845

  19. Ethics and resource allocation: an economist's view.

    PubMed

    McGuire, A

    1986-01-01

    This paper debates some of the issues involved in attempting to apply economic analysis to the health care sector when medical ethics plays such an important part in determining the allocation of resources in that sector. Two distinct ethical positions are highlighted as being fundamental to the understanding of resource allocation in this sector -- deontological and utilitarian theories of ethics. It is argued that medical ethics are often narrowly conceived in that there is a tendency for the individual, rather than society at large, to form the focal point of the production of the service "health care'. Thus medical ethics have been dominated by individualistic ethical coded which do not fully consider questions relating to resource allocation at a social level. It is further argued that the structure of the health care sector augments these "individualistic' ethics. It is also suggested that different actors in the health care sector address questions of resource allocation with respect to different time periods, and that this serves to further enhance the influence of "individualistic' ethical codes in this sector. PMID:3092362

  20. Principles of allocation of health care resources.

    PubMed Central

    Knox, E G

    1978-01-01

    The methods and principles of allocating centrally provided health care resources to regions and areas are reviewed using the report of the Resource Allocation Working Party (RAWP) (Department of Health and Social Security, 1976) and the consultative document (Department of Health and Social Security, 1976a) as a basis. A range of practical problems arising from these papers (especially the report of the RAWP) is described and traced to the terms of reference. It is concluded that the RAWP misinterpreted aspects of social and administrative reality, and it failed to recognise clearly that the several principles on which it had to work conflicted with each other and demanded decisions of priority. The consequential errors led to (a) an injudicious imposition of 'objectivity' at all levels of allocation, (b) an unjustified insistence that the same method be used at each administrative level in an additive and transitive manner, (c) the exclusion of general practitioner services from their considerations, (d) a failure to delineate those decisions which are in fact political decisions, thus to concatenate them, inappropriately, with technical and professional issues. The main requirement in a revised system is for a mechanism which allocates different priorities to different principles at each appropriate administrative and distributive level, and adapts the working methods of each tier to meet separately defined objectives. PMID:262585

  1. Back to the Basics with Resource Allocations.

    ERIC Educational Resources Information Center

    Matlock, John; Humphries, Frederick S.

    A resource allocation and utilization study was undertaken of Tennessee State University and the results, recommendations and policy decisions that evolved are presented. The President's Council, comprised of the President, the Vice Presidents, and the Director of Planning, Management and Evaluation, directed the study. Data from the Office of…

  2. Development of a Capital Allocations Formula.

    ERIC Educational Resources Information Center

    Thompson, I.; And Others.

    A description is presented of the present state of development of a capital allocations formula for general building project costs at the University of Toronto. The first part of the paper is devoted to a discussion of the objectives and application of the formula in its present state. A detailed description of the available data and the…

  3. 45 CFR 400.13 - Cost allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Welfare Regulations Relating to Public Welfare OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES REFUGEE RESETTLEMENT PROGRAM Grants to States for Refugee Resettlement Award of Grants to States § 400.13 Cost allocation. (a) A State must...

  4. 45 CFR 400.13 - Cost allocation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Welfare Regulations Relating to Public Welfare OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES REFUGEE RESETTLEMENT PROGRAM Grants to States for Refugee Resettlement Award of Grants to States § 400.13 Cost allocation. (a) A State must...

  5. 45 CFR 400.13 - Cost allocation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Welfare Regulations Relating to Public Welfare OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES REFUGEE RESETTLEMENT PROGRAM Grants to States for Refugee Resettlement Award of Grants to States § 400.13 Cost allocation. (a) A State must...

  6. 45 CFR 400.13 - Cost allocation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Welfare Regulations Relating to Public Welfare OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES REFUGEE RESETTLEMENT PROGRAM Grants to States for Refugee Resettlement Award of Grants to States § 400.13 Cost allocation. (a) A State must...

  7. 45 CFR 400.13 - Cost allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Welfare Regulations Relating to Public Welfare OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES REFUGEE RESETTLEMENT PROGRAM Grants to States for Refugee Resettlement Award of Grants to States § 400.13 Cost allocation. (a) A State must...

  8. 50 CFR 648.87 - Sector allocation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... permit sanctions pursuant to 15 CFR part 904. If an ACE allocated to a sector is not exceeded in a given... CFR part 904, each sector, permit/vessel owner, and vessel operator participating in the sector may be... otherwise required pursuant to § 648.86(l). Discards of undersized regulated species or ocean pout by...

  9. Modifications to the EOPS Allocation Formula.

    ERIC Educational Resources Information Center

    Dyste, Ron; Agosto, David

    A modified Extended Opportunity Programs and Services (EOPS) allocation formula has been recommended for implementation in the California community colleges by the end of 1982-83. The modified formula has been designed to shift funding policy toward performance outputs as distinct from inputs. The current formula is based upon four weighted

  10. Limits on linearity of missile allocation optimization

    SciTech Connect

    Canavan, G.H.

    1997-12-01

    Optimizations of missile allocation based on linearized exchange equations produce accurate allocations, but the limits of validity of the linearization are not known. These limits are explored in the context of the upload of weapons by one side to initially small, equal forces of vulnerable and survivable weapons. The analysis compares analytic and numerical optimizations and stability induces based on aggregated interactions of the two missile forces, the first and second strikes they could deliver, and they resulting costs. This note discusses the costs and stability indices induced by unilateral uploading of weapons to an initially symmetrical low force configuration. These limits are quantified for forces with a few hundred missiles by comparing analytic and numerical optimizations of first strike costs. For forces of 100 vulnerable and 100 survivable missiles on each side, the analytic optimization agrees closely with the numerical solution. For 200 vulnerable and 200 survivable missiles on each side, the analytic optimization agrees with the induces to within about 10%, but disagrees with the allocation of the side with more weapons by about 50%. The disagreement comes from the interaction of the possession of more weapons with the shift of allocation from missiles to value that they induce.

  11. Ground data systems resource allocation process

    NASA Technical Reports Server (NTRS)

    Berner, Carol A.; Durham, Ralph; Reilly, Norman B.

    1989-01-01

    The Ground Data Systems Resource Allocation Process at the Jet Propulsion Laboratory provides medium- and long-range planning for the use of Deep Space Network and Mission Control and Computing Center resources in support of NASA's deep space missions and Earth-based science. Resources consist of radio antenna complexes and associated data processing and control computer networks. A semi-automated system was developed that allows operations personnel to interactively generate, edit, and revise allocation plans spanning periods of up to ten years (as opposed to only two or three weeks under the manual system) based on the relative merit of mission events. It also enhances scientific data return. A software system known as the Resource Allocation and Planning Helper (RALPH) merges the conventional methods of operations research, rule-based knowledge engineering, and advanced data base structures. RALPH employs a generic, highly modular architecture capable of solving a wide variety of scheduling and resource sequencing problems. The rule-based RALPH system has saved significant labor in resource allocation. Its successful use affirms the importance of establishing and applying event priorities based on scientific merit, and the benefit of continuity in planning provided by knowledge-based engineering. The RALPH system exhibits a strong potential for minimizing development cycles of resource and payload planning systems throughout NASA and the private sector.

  12. The Allocation of Resources in a University

    ERIC Educational Resources Information Center

    Koch, James V.

    1974-01-01

    The paper describes a linear programming model which generates explicit quantitative information about (1) the optimal allocation of resources inside the public university (2) the "shadow price" attached to each input used in the academic process; and (3) the optimal mixture of academic outputs produced by the university. (KM)

  13. How to Allocate Personnel Costs of Reference.

    ERIC Educational Resources Information Center

    Spencer, Carol

    In July 1974, at the American Library Association Convention, a symposium on reference measurement was held. The basic premise was that work sampling and random time sampling with self-observation were the best methods of allocating personnel costs of reference services at the Library of the College of Physicians of Philadelphia. First, reasons…

  14. 42 CFR 24.2 - Allocation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Allocation. 24.2 Section 24.2 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES PERSONNEL SENIOR BIOMEDICAL RESEARCH SERVICE § 24... authorized by Congress and which directly support the research goals and priorities of the Department....

  15. 42 CFR 24.2 - Allocation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Allocation. 24.2 Section 24.2 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES PERSONNEL SENIOR BIOMEDICAL RESEARCH SERVICE § 24... authorized by Congress and which directly support the research goals and priorities of the Department....

  16. 42 CFR 24.2 - Allocation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Allocation. 24.2 Section 24.2 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES PERSONNEL SENIOR BIOMEDICAL RESEARCH SERVICE § 24... authorized by Congress and which directly support the research goals and priorities of the Department....

  17. 24 CFR 574.130 - Formula allocations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... population data provided by the U.S. Census. The number of cases of acquired immunodeficiency syndrome used... statistical areas with more than 500,000 population. Each qualifying city's allocation reflects its EMSA's... AIDS. The high incidence factor is computed by multiplying the population of the...

  18. Resource Allocation Patterns and Student Achievement

    ERIC Educational Resources Information Center

    James, Lori; Pate, James; Leech, Donald; Martin, Ellice; Brockmeier, Lantry; Dees, Elizabeth

    2011-01-01

    This quantitative research study was designed to examine the relationship between system resource allocation patterns and student achievement, as measured by eighth grade Criterion-Referenced Competency Test (CRCT) mathematics, eighth grade CRCT reading, eleventh grade Georgia High School Graduation Test (GHSGT) mathematics, eleventh grade and…

  19. Discrete Resource Allocation in Visual Working Memory

    ERIC Educational Resources Information Center

    Barton, Brian; Ester, Edward F.; Awh, Edward

    2009-01-01

    Are resources in visual working memory allocated in a continuous or a discrete fashion? On one hand, flexible resource models suggest that capacity is determined by a central resource pool that can be flexibly divided such that items of greater complexity receive a larger share of resources. On the other hand, if capacity in working memory is…

  20. Rural Attitudes toward Public Welfare Allocation.

    ERIC Educational Resources Information Center

    Davis, Laura F.

    1988-01-01

    Examines 1984 Wyoming opinion poll. Wyoming respondents agreed welfare allocation should be based on need, but 50 percent believed welfare recipients should not receive more than minimum-wage income. Wyoming's welfare support is lower than national average. Rurality may contribute to results. Recommends ways to increase rural support for welfare…

  1. controlling retained insurance costs through an allocation.

    PubMed

    Frese, Richard C

    2015-06-01

    An insurance allocation may help a hospital or health system achieve the following goals for its professional liability and workers' compensation self-insurance or large-deductible programs: Loss-control incentive. Stability. Equity. Comprehension. Ease of administration. PMID:26665334

  2. 42 CFR 24.2 - Allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Allocation. 24.2 Section 24.2 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES PERSONNEL SENIOR BIOMEDICAL RESEARCH SERVICE § 24... talent. (e) The Secretary will ensure that SBRS slots are used in support of high priority...

  3. 42 CFR 24.2 - Allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Allocation. 24.2 Section 24.2 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES PERSONNEL SENIOR BIOMEDICAL RESEARCH SERVICE § 24... talent. (e) The Secretary will ensure that SBRS slots are used in support of high priority...

  4. Optimal Allocation Of Tasks In Hypercube Computers

    NASA Technical Reports Server (NTRS)

    Salama, Moktar A.; Price, Camille C.

    1990-01-01

    Uniform tasks distributed uniformly or else assigned to one processor. Investigation in theory of scheduling yielded optimal scheme for allocation of tasks among digital data processors in hypercube ensemble. Applies to tasks that require equal time to execute, performed in any order, and between any two of which equal amounts of communication required. Reduces overall processing time for given set of computational tasks.

  5. 10 CFR 455.31 - Allocation formulas.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Allocation formulas. 455.31 Section 455.31 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION GRANT PROGRAMS FOR SCHOOLS AND HOSPITALS AND BUILDINGS OWNED BY...) Financial assistance for conducting technical assistance programs and acquiring and installing...

  6. 10 CFR 455.31 - Allocation formulas.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Allocation formulas. 455.31 Section 455.31 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION GRANT PROGRAMS FOR SCHOOLS AND HOSPITALS AND BUILDINGS OWNED BY...) Financial assistance for conducting technical assistance programs and acquiring and installing...

  7. 10 CFR 455.31 - Allocation formulas.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Allocation formulas. 455.31 Section 455.31 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION GRANT PROGRAMS FOR SCHOOLS AND HOSPITALS AND BUILDINGS OWNED BY...) Financial assistance for conducting technical assistance programs and acquiring and installing...

  8. Allocation of Human Resources for Collection Development.

    ERIC Educational Resources Information Center

    Bryant, Bonita

    1986-01-01

    This article reviews personnel administration techniques that have been used to establish work-load parameters, but offer no aid in subject deployment. A model which identifies elements that must be included in a consideration of work-load measurement and subject allocation for library collection development tasks is presented. Thirty-four…

  9. 45 CFR 304.15 - Cost allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Department in accordance with the requirements contained in Subpart E of 45 CFR part 95. Subpart E also sets... Welfare Regulations Relating to Public Welfare OFFICE OF CHILD SUPPORT ENFORCEMENT (CHILD SUPPORT... FEDERAL FINANCIAL PARTICIPATION § 304.15 Cost allocation. A State agency in support of its claims...

  10. 45 CFR 304.15 - Cost allocation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Department in accordance with the requirements contained in Subpart E of 45 CFR part 95. Subpart E also sets... Welfare Regulations Relating to Public Welfare OFFICE OF CHILD SUPPORT ENFORCEMENT (CHILD SUPPORT... FEDERAL FINANCIAL PARTICIPATION § 304.15 Cost allocation. A State agency in support of its claims...

  11. 50 CFR 660.55 - Allocations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Allocations. 660.55 Section 660.55... regulations) is managed under regulations at 50 CFR part 300, subpart E. The PCGFMP sets the trawl bycatch... through 2014 and, beginning in 2015, not to exceed 100,000 pounds annually for legal size halibut...

  12. 50 CFR 660.55 - Allocations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Allocations. 660.55 Section 660.55... regulations at 50 CFR part 300, subpart E. The PCGFMP sets the trawl bycatch mortality limit at 15 percent of... in 2015, not to exceed 100,000 pounds annually for legal size halibut (net weight). The TCEY used...

  13. 50 CFR 660.55 - Allocations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Allocations. 660.55 Section 660.55... regulations at 50 CFR part 300, subpart E. The PCGFMP sets the trawl bycatch mortality limit at 15 percent of... in 2015, not to exceed 100,000 pounds annually for legal size halibut (net weight). The TCEY used...

  14. Resource Allocation in U. K. Universities.

    ERIC Educational Resources Information Center

    Taylor, Bryan J. R.

    1982-01-01

    Information on resource allocation in United Kingdom (UK) universities, which is derived from a study by a Working Party of the Conference of University administrators, is presented. Attention is directed to: structures and constitutions; the use of norms and formulas; administration and central services; minor works, maintenance, and space; and

  15. Allocating Faculty in the Budgeting Process.

    ERIC Educational Resources Information Center

    Kemper, Gene A.

    1985-01-01

    The University of North Dakota conducted a feasibility study to develop a faculty funding formula that would serve as an internally acceptable guideline and an externally justifiable procedure for allocating faculty in the budgeting process. The current formula is reviewed, and appropriate formula revisions are suggested. (MLW)

  16. On the stochastic thermodynamics of reactive systems

    NASA Astrophysics Data System (ADS)

    De Decker, Yannick

    2015-06-01

    We develop a theoretical framework for the stochastic thermodynamics of reactive systems. We show that the transition probabilities per unit time of reactive events must satisfy specific constraints, in order for stochastic approaches to lead to physically meaningful results in the macroscopic limit. We discuss how these constraints affect the properties of stochastic fluxes and forces, and entropy production. We also see how they can be used to derive various expressions of fluctuation theorems.

  17. Stochastic Vorticity and Associated Filtering Theory

    SciTech Connect

    Amirdjanova, A.; Kallianpur, G.

    2002-12-19

    The focus of this work is on a two-dimensional stochastic vorticity equation for an incompressible homogeneous viscous fluid. We consider a signed measure-valued stochastic partial differential equation for a vorticity process based on the Skorohod-Ito evolution of a system of N randomly moving point vortices. A nonlinear filtering problem associated with the evolution of the vorticity is considered and a corresponding Fujisaki-Kallianpur-Kunita stochastic differential equation for the optimal filter is derived.

  18. The fully implicit stochastic- ? method for stiff stochastic differential equations

    NASA Astrophysics Data System (ADS)

    Safique Ahmad, Sk.; Chandra Parida, Nigam; Raha, Soumyendu

    2009-12-01

    A fully implicit integration method for stochastic differential equations with significant multiplicative noise and stiffness in both the drift and diffusion coefficients has been constructed, analyzed and illustrated with numerical examples in this work. The method has strong order 1.0 consistency and has user-selectable parameters that allow the user to expand the stability region of the method to cover almost the entire drift-diffusion stability plane. The large stability region enables the method to take computationally efficient time steps. A system of chemical Langevin equations simulated with the method illustrates its computational efficiency.

  19. The allocation of cargo to channel missions

    SciTech Connect

    Liu, Cheng; Harrison, G.

    1992-01-01

    Each month the armed services provide a forecast of tons of cargo by channel to MAC. The purpose of the Channels Allocation Algorithm is to allocate cargo requirements to specific Channel Missions. The objective of the allocation is algorithm is to minimize frequency and cargo requirements shortfall. The constraints on the allocation model include flying hours, channel frequencies, mission structure, mission operation days, and aircraft capacity. Cargo requirements shortfall is defined as the tonnage of cargo not moved from the airfields in the United States that are channel staging points to overseas locations. Channel frequencies are defined by the number of times a destination is served by an origin in one month. The mission structures are defined as sets of missions usually in the form of circuit. Mission operating days are determined by the operating day rules for the month, or they can be input by the user for an individual month. One of the assumptions in this model is that there is only one transshipment allowed between any origin and a destination if there is no mission that actually connects the stations. The transshipment stations are also restricted in that only certain stations can serve as transshipment stations. The Channels Allocation Algorithm consists of two linear programs that incorporate three objectives. The objectives are: (1) to minimize that number of frequency channels not met. (2) to minimize cargo shortfall, and (3) to minimize operating cost. The first linear program minimizes frequency channels not met, subject to the mission structure, number of times the mission operates, and total flying hours available. The second linear program minimizes the fleet operating cost cargo handling cost, and cargo shortfall, subject to frequency channels met by the first linear program, aircraft capacity, and total flying hours available. This document is comprised of viewgraphs.

  20. The allocation of cargo to channel missions

    SciTech Connect

    Liu, Cheng; Harrison, G.

    1992-06-01

    Each month the armed services provide a forecast of tons of cargo by channel to MAC. The purpose of the Channels Allocation Algorithm is to allocate cargo requirements to specific Channel Missions. The objective of the allocation is algorithm is to minimize frequency and cargo requirements shortfall. The constraints on the allocation model include flying hours, channel frequencies, mission structure, mission operation days, and aircraft capacity. Cargo requirements shortfall is defined as the tonnage of cargo not moved from the airfields in the United States that are channel staging points to overseas locations. Channel frequencies are defined by the number of times a destination is served by an origin in one month. The mission structures are defined as sets of missions usually in the form of circuit. Mission operating days are determined by the operating day rules for the month, or they can be input by the user for an individual month. One of the assumptions in this model is that there is only one transshipment allowed between any origin and a destination if there is no mission that actually connects the stations. The transshipment stations are also restricted in that only certain stations can serve as transshipment stations. The Channels Allocation Algorithm consists of two linear programs that incorporate three objectives. The objectives are: (1) to minimize that number of frequency channels not met. (2) to minimize cargo shortfall, and (3) to minimize operating cost. The first linear program minimizes frequency channels not met, subject to the mission structure, number of times the mission operates, and total flying hours available. The second linear program minimizes the fleet operating cost cargo handling cost, and cargo shortfall, subject to frequency channels met by the first linear program, aircraft capacity, and total flying hours available. This document is comprised of viewgraphs.

  1. Secretaries: Help Wanted Ads Survey.

    ERIC Educational Resources Information Center

    Fusselman, Kay

    1985-01-01

    Three articles concerning help wanted ads for secretaries are presented. They concern results of the 1985 Newspaper Help Wanted Advertisements Survey, types of requirements sought in the typical help wanted ad for secretaries, and the range of salaries offered to secretaries. (CT)

  2. Ultraviolet asymptotics for quasiperiodic AdS4 perturbations

    NASA Astrophysics Data System (ADS)

    Craps, Ben; Evnin, Oleg; Jai-akson, Puttarak; Vanhoof, Joris

    2015-10-01

    Spherically symmetric perturbations in AdS-scalar field systems of small amplitude ɛ approximately periodic on time scales of order 1/ ɛ 2 (in the sense that no significant transfer of energy between the AdS normal modes occurs) have played an important role in considerations of AdS stability. They are seen as anchors of stability islands where collapse of small perturbations to black holes does not occur. (This collapse, if it happens, typically develops on time scales of the order 1/ ɛ 2.) We construct an analytic treatment of the frequency spectra of such quasiperiodic perturbations, paying special attention to the large frequency asymptotics. For the case of a self-interacting ϕ 4 scalar field in a non-dynamical AdS background, we arrive at a fairly complete analytic picture involving quasiperiodic spectra with an exponential suppression modulated by a power law at large mode numbers. For the case of dynamical gravity, the structure of the large frequency asymptotics is more complicated. We give analytic explanations for the general qualitative features of quasiperiodic solutions localized around a single mode, in close parallel to our discussion of the probe scalar field, and find numerical evidence for logarithmic modulations in the gravitational quasiperiodic spectra existing on top of the formulas previously reported in the literature.

  3. Lorentzian AdS geometries, wormholes, and holography

    SciTech Connect

    Arias, Raul E.; Silva, Guillermo A.; Botta Cantcheff, Marcelo

    2011-03-15

    We investigate the structure of two-point functions for the quantum field theory dual to an asymptotically Lorentzian Anti de Sitter (AdS) wormhole. The bulk geometry is a solution of five-dimensional second-order Einstein-Gauss-Bonnet gravity and causally connects two asymptotically AdS spacetimes. We revisit the Gubser-Klebanov-Polyakov-Witten prescription for computing two-point correlation functions for dual quantum field theories operators O in Lorentzian signature and we propose to express the bulk fields in terms of the independent boundary values {phi}{sub 0}{sup {+-}} at each of the two asymptotic AdS regions; along the way we exhibit how the ambiguity of normalizable modes in the bulk, related to initial and final states, show up in the computations. The independent boundary values are interpreted as sources for dual operators O{sup {+-}} and we argue that, apart from the possibility of entanglement, there exists a coupling between the degrees of freedom living at each boundary. The AdS{sub 1+1} geometry is also discussed in view of its similar boundary structure. Based on the analysis, we propose a very simple geometric criterion to distinguish coupling from entanglement effects among two sets of degrees of freedom associated with each of the disconnected parts of the boundary.

  4. One-loop diagrams in AdS space

    SciTech Connect

    Hung Lingyan; Shang Yanwen

    2011-01-15

    We study the complex scalar loop corrections to the boundary-boundary gauge two-point function in pure AdS space in Poincare coordinates, in the presence of boundary quadratic perturbations to the scalar. These perturbations correspond to double-trace perturbations in the dual CFT and modify the boundary conditions of the bulk scalars in AdS. We find that, in addition to the usual UV divergences, the one-loop calculation suffers from a divergence originating in the limit as the loop vertices approach the AdS horizon. We show that this type of divergence is independent of the boundary coupling; making use of this we extract the finite relative variation of the imaginary part of the loop via Cutkosky rules as the boundary perturbation varies. Applying our methods to compute the effects of a time-dependent impurity to the conductivities using the replica trick in AdS/CFT, we find that generally an IR-relevant disorder reduces the conductivity and that in the extreme low frequency limit the correction due to the impurities overwhelms the planar CFT result even though it is supposedly 1/N{sup 2} suppressed. We also comment on the more physical scenario of a time-independent impurity.

  5. Stochastics In Circumplanetary Dust Dynamics

    NASA Astrophysics Data System (ADS)

    Spahn, F.; Krivov, A. V.; Sremcevic, M.; Schwarz, U.; Kurths, J.

    Charged dust grains in circumplanetary environments experience, beyond various de- terministic forces, also stochastic perturbations: E.g., fluctuations of the magnetic field, the charge of the grains etc. Here, we investigate the dynamics of a dust population in a circular orbit around the planet which is perturbed by a stochastic magnetic field B , modeled by an isotropi- cally Gaussian white noise. The resulting perturbation equations give rise to a modi- 2 fied diffusion of the inclinations and eccentricities ­ x D [t +/- sin[2nt]/(2n)] (x - alias for eccentricity e and the inclination i, t - time). The diffusion coefficient is found to be D = [G]2/n, where the gyrofrequency and the orbital frequency are denoted by G, and n, respectively. This behavior has been checked by numerical experiments. We have chosen dust grains (1µm in radius) initially moving in circular orbits around a planet (Jupiter) and integrated numerically their trajectories over their typical lifetimes (100 years). The particles were exposed to a Gaussian fluctuating magnetic field B obeying the same statistical properties as in the analytical treatment. In this case, the theoretical 2 findings have been confirmed according to x D t with a diffusion coefficient of D G/n. 2 The theoretical studies showed the statistical properties of B being of decisive im- portance. To this aim, we analyzed the magnetic field data measured by the Galileo magnetometer at Jupiter and found almost Gaussian fluctuations of about 5 % of the mean field and exponentially decaying correlations. This results in a diffusion in the space of orbital elements of at least 1...5 % (variations of inclinations and eccentric- ity) over the lifetime of the dust grains. For smaller dusty motes stochastics might well dominate the dynamics.

  6. Collective dynamics from stochastic thermodynamics

    NASA Astrophysics Data System (ADS)

    Sasa, Shin-ichi

    2015-04-01

    From a viewpoint of stochastic thermodynamics, we derive equations that describe the collective dynamics near the order-disorder transition in the globally coupled XY model and near the synchronization-desynchronization transition in the Kuramoto model. A new way of thinking is to interpret the deterministic time evolution of a macroscopic variable as an external operation to a thermodynamic system. We then find that the irreversible work determines the equation for the collective dynamics. When analyzing the Kuramoto model, we employ a generalized concept of irreversible work which originates from a non-equilibrium identity associated with steady state thermodynamics.

  7. Stochastic Models of Human Errors

    NASA Technical Reports Server (NTRS)

    Elshamy, Maged; Elliott, Dawn M. (Technical Monitor)

    2002-01-01

    Humans play an important role in the overall reliability of engineering systems. More often accidents and systems failure are traced to human errors. Therefore, in order to have meaningful system risk analysis, the reliability of the human element must be taken into consideration. Describing the human error process by mathematical models is a key to analyzing contributing factors. Therefore, the objective of this research effort is to establish stochastic models substantiated by sound theoretic foundation to address the occurrence of human errors in the processing of the space shuttle.

  8. Stochastic thermodynamics of information processing

    NASA Astrophysics Data System (ADS)

    Cardoso Barato, Andre

    2015-03-01

    We consider two recent advancements on theoretical aspects of thermodynamics of information processing. First we show that the theory of stochastic thermodynamics can be generalized to include information reservoirs. These reservoirs can be seen as a sequence of bits which has its Shannon entropy changed due to the interaction with the system. Second we discuss bipartite systems, which provide a convenient description of Maxwell's demon. Analyzing a special class of bipartite systems we show that they can be used to study cellular information processing, allowing for the definition of an entropic rate that quantifies how much a cell learns about a fluctuating external environment and that is bounded by the thermodynamic entropy production.

  9. Constrained Stochastic Extended Redundancy Analysis.

    PubMed

    DeSarbo, Wayne S; Hwang, Heungsun; Stadler Blank, Ashley; Kappe, Eelco

    2015-06-01

    We devise a new statistical methodology called constrained stochastic extended redundancy analysis (CSERA) to examine the comparative impact of various conceptual factors, or drivers, as well as the specific predictor variables that contribute to each driver on designated dependent variable(s). The technical details of the proposed methodology, the maximum likelihood estimation algorithm, and model selection heuristics are discussed. A sports marketing consumer psychology application is provided in a Major League Baseball (MLB) context where the effects of six conceptual drivers of game attendance and their defining predictor variables are estimated. Results compare favorably to those obtained using traditional extended redundancy analysis (ERA). PMID:24327066

  10. Stochastic solution to quantum dynamics

    NASA Technical Reports Server (NTRS)

    John, Sarah; Wilson, John W.

    1994-01-01

    The quantum Liouville equation in the Wigner representation is solved numerically by using Monte Carlo methods. For incremental time steps, the propagation is implemented as a classical evolution in phase space modified by a quantum correction. The correction, which is a momentum jump function, is simulated in the quasi-classical approximation via a stochastic process. The technique, which is developed and validated in two- and three- dimensional momentum space, extends an earlier one-dimensional work. Also, by developing a new algorithm, the application to bound state motion in an anharmonic quartic potential shows better agreement with exact solutions in two-dimensional phase space.

  11. Stochastic Gain in Population Dynamics

    NASA Astrophysics Data System (ADS)

    Traulsen, Arne; Rhl, Torsten; Schuster, Heinz Georg

    2004-07-01

    We introduce an extension of the usual replicator dynamics to adaptive learning rates. We show that a population with a dynamic learning rate can gain an increased average payoff in transient phases and can also exploit external noise, leading the system away from the Nash equilibrium, in a resonancelike fashion. The payoff versus noise curve resembles the signal to noise ratio curve in stochastic resonance. Seen in this broad context, we introduce another mechanism that exploits fluctuations in order to improve properties of the system. Such a mechanism could be of particular interest in economic systems.

  12. Stochastic quantization for complex actions

    SciTech Connect

    Menezes, G.; Svaiter, N. F.

    2008-10-15

    We use the stochastic quantization method to study systems with complex valued path integral weights. We assume a Langevin equation with a memory kernel and Einstein's relations with colored noise. The equilibrium solution of this non-Markovian Langevin equation is analyzed. We show that for a large class of elliptic non-Hermitian operators acting on scalar functions on Euclidean space, which define different models in quantum field theory, converge to an equilibrium state in the asymptotic limit of the Markov parameter {tau}{yields}{infinity}. Moreover, as we expected, we obtain the Schwinger functions of the theory.

  13. 50 CFR 600.325 - National Standard 4-Allocations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... fishermen. (2) Analysis of allocations. Each FMP should contain a description and analysis of the... included in the discussion. The analysis should relate the recommended allocations to the FMP's...

  14. 26 CFR 1.826-4 - Allocation of expenses.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Companies and Other Than Fire Or Flood Insurance Companies Which Operate on Basis of Perpetual Policies Or Premium Deposits) § 1.826-4 Allocation of expenses. An attorney-in-fact allocating expenses as required...

  15. Stochastic non-linear oscillator models of EEG: the Alzheimer's disease case.

    PubMed

    Ghorbanian, Parham; Ramakrishnan, Subramanian; Ashrafiuon, Hashem

    2015-01-01

    In this article, the Electroencephalography (EEG) signal of the human brain is modeled as the output of stochastic non-linear coupled oscillator networks. It is shown that EEG signals recorded under different brain states in healthy as well as Alzheimer's disease (AD) patients may be understood as distinct, statistically significant realizations of the model. EEG signals recorded during resting eyes-open (EO) and eyes-closed (EC) resting conditions in a pilot study with AD patients and age-matched healthy control subjects (CTL) are employed. An optimization scheme is then utilized to match the output of the stochastic Duffing-van der Pol double oscillator network with EEG signals recorded during each condition for AD and CTL subjects by selecting the model physical parameters and noise intensity. The selected signal characteristics are power spectral densities in major brain frequency bands Shannon and sample entropies. These measures allow matching of linear time varying frequency content as well as non-linear signal information content and complexity. The main finding of the work is that statistically significant unique models represent the EC and EO conditions for both CTL and AD subjects. However, it is also shown that the inclusion of sample entropy in the optimization process, to match the complexity of the EEG signal, enhances the stochastic non-linear oscillator model performance. PMID:25964756

  16. Stochastic non-linear oscillator models of EEG: the Alzheimer's disease case

    PubMed Central

    Ghorbanian, Parham; Ramakrishnan, Subramanian; Ashrafiuon, Hashem

    2015-01-01

    In this article, the Electroencephalography (EEG) signal of the human brain is modeled as the output of stochastic non-linear coupled oscillator networks. It is shown that EEG signals recorded under different brain states in healthy as well as Alzheimer's disease (AD) patients may be understood as distinct, statistically significant realizations of the model. EEG signals recorded during resting eyes-open (EO) and eyes-closed (EC) resting conditions in a pilot study with AD patients and age-matched healthy control subjects (CTL) are employed. An optimization scheme is then utilized to match the output of the stochastic Duffing—van der Pol double oscillator network with EEG signals recorded during each condition for AD and CTL subjects by selecting the model physical parameters and noise intensity. The selected signal characteristics are power spectral densities in major brain frequency bands Shannon and sample entropies. These measures allow matching of linear time varying frequency content as well as non-linear signal information content and complexity. The main finding of the work is that statistically significant unique models represent the EC and EO conditions for both CTL and AD subjects. However, it is also shown that the inclusion of sample entropy in the optimization process, to match the complexity of the EEG signal, enhances the stochastic non-linear oscillator model performance. PMID:25964756

  17. 25 CFR 170.200 - How does BIA allocate IRR Program funds?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ROADS PROGRAM Indian Reservation Roads Program Funding Tribal Transportation Allocation Methodology... Transportation Allocation Methodology (TTAM) that BIA uses to allocate IRR Program funds. After...

  18. Recently fixed carbon allocation in strawberry plants and concurrent inorganic nitrogen uptake through arbuscular mycorrhizal fungi.

    PubMed

    Tomè, Elisabetta; Tagliavini, Massimo; Scandellari, Francesca

    2015-05-01

    Most crop species form a symbiotic association with arbuscular mycorrhizal (AM) fungi, receiving plant photosynthate and exchanging nutrients from the soil. The plant carbon (C) allocation to AM fungi and the nitrogen feedback are rarely studied together. In this study, a dual (13)CO2 and (15)NH4(15)NO3 pulse labeling experiment was carried out to determine the allocation of recent photosynthates to mycorrhizal hyphae and the translocation of N absorbed by hyphae to strawberry plants. Plants were grown in pots in which a 50 μm mesh net allowed the physical separation of the mycorrhizal hyphae from the roots in one portion of the pot. An inorganic source of (15)N was added to the hyphal compartment at the same time of the (13)CO2 pulse labeling. One and seven days after pulse labeling, the plants were destructively harvested and the amount of the recently fixed carbon (C) and of the absorbed N was determined. (13)C allocated to belowground organs such as roots and mycorrhizal hyphae accounted for an average of 10%, with 4.3% allocated to mycorrhizal hyphae within the first 24h after the pulse labeling. Mycorrhizae absorbed labeled inorganic nitrogen, of which almost 23% was retained in the fungal mycelium. The N uptake was linearly correlated with the (13)C fixed by the plants suggesting a positive correlation between a plant photosynthetic rate and the hyphal absorption capacity. PMID:25841208

  19. MCdevelop - a universal framework for Stochastic Simulations

    NASA Astrophysics Data System (ADS)

    Slawinska, M.; Jadach, S.

    2011-03-01

    We present MCdevelop, a universal computer framework for developing and exploiting the wide class of Stochastic Simulations (SS) software. This powerful universal SS software development tool has been derived from a series of scientific projects for precision calculations in high energy physics (HEP), which feature a wide range of functionality in the SS software needed for advanced precision Quantum Field Theory calculations for the past LEP experiments and for the ongoing LHC experiments at CERN, Geneva. MCdevelop is a "spin-off" product of HEP to be exploited in other areas, while it will still serve to develop new SS software for HEP experiments. Typically SS involve independent generation of large sets of random "events", often requiring considerable CPU power. Since SS jobs usually do not share memory it makes them easy to parallelize. The efficient development, testing and running in parallel SS software requires a convenient framework to develop software source code, deploy and monitor batch jobs, merge and analyse results from multiple parallel jobs, even before the production runs are terminated. Throughout the years of development of stochastic simulations for HEP, a sophisticated framework featuring all the above mentioned functionality has been implemented. MCdevelop represents its latest version, written mostly in C++ (GNU compiler gcc). It uses Autotools to build binaries (optionally managed within the KDevelop 3.5.3 Integrated Development Environment (IDE)). It uses the open-source ROOT package for histogramming, graphics and the mechanism of persistency for the C++ objects. MCdevelop helps to run multiple parallel jobs on any computer cluster with NQS-type batch system. Program summaryProgram title:MCdevelop Catalogue identifier: AEHW_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHW_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 48 136 No. of bytes in distributed program, including test data, etc.: 355 698 Distribution format: tar.gz Programming language: ANSI C++ Computer: Any computer system or cluster with C++ compiler and UNIX-like operating system. Operating system: Most UNIX systems, Linux. The application programs were thoroughly tested under Ubuntu 7.04, 8.04 and CERN Scientific Linux 5. Has the code been vectorised or parallelised?: Tools (scripts) for optional parallelisation on a PC farm are included. RAM: 500 bytes Classification: 11.3 External routines: ROOT package version 5.0 or higher ( http://root.cern.ch/drupal/). Nature of problem: Developing any type of stochastic simulation program for high energy physics and other areas. Solution method: Object Oriented programming in C++ with added persistency mechanism, batch scripts for running on PC farms and Autotools.

  20. The allocation of ecosystem net primary productivity in tropical forests

    PubMed Central

    Malhi, Yadvinder; Doughty, Christopher; Galbraith, David

    2011-01-01

    The allocation of the net primary productivity (NPP) of an ecosystem between canopy, woody tissue and fine roots is an important descriptor of the functioning of that ecosystem, and an important feature to correctly represent in terrestrial ecosystem models. Here, we collate and analyse a global dataset of NPP allocation in tropical forests, and compare this with the representation of NPP allocation in 13 terrestrial ecosystem models. On average, the data suggest an equal partitioning of allocation between all three main components (mean 34 ± 6% canopy, 39 ± 10% wood, 27 ± 11% fine roots), but there is substantial site-to-site variation in allocation to woody tissue versus allocation to fine roots. Allocation to canopy (leaves, flowers and fruit) shows much less variance. The mean allocation of the ecosystem models is close to the mean of the data, but the spread is much greater, with several models reporting allocation partitioning outside of the spread of the data. Where all main components of NPP cannot be measured, litterfall is a good predictor of overall NPP (r2 = 0.83 for linear fit forced through origin), stem growth is a moderate predictor and fine root production a poor predictor. Across sites the major component of variation of allocation is a shifting allocation between wood and fine roots, with allocation to the canopy being a relatively invariant component of total NPP. This suggests the dominant allocation trade-off is a ‘fine root versus wood’ trade-off, as opposed to the expected ‘root–shoot’ trade-off; such a trade-off has recently been posited on theoretical grounds for old-growth forest stands. We conclude by discussing the systematic biases in estimates of allocation introduced by missing NPP components, including herbivory, large leaf litter and root exudates production. These biases have a moderate effect on overall carbon allocation estimates, but are smaller than the observed range in allocation values across sites. PMID:22006964

  1. Observing quantum gravity in asymptotically AdS space

    NASA Astrophysics Data System (ADS)

    Emelyanov, Slava

    2015-12-01

    The question is studied of whether an observer can discover quantum gravity in the semiclassical regime. It is shown that it is indeed possible to probe a certain quantum gravity effect by employing an appropriately designed detector. The effect is related to the possibility of having topologically inequivalent geometries in the path-integral approach at the same time. A conformal field theory (CFT) state which is expected to describe the eternal anti-de Sitter (AdS) black hole in the large-N limit is discussed. It is argued under certain assumptions that the black hole boundary should be merely a patch of the entire AdS boundary. This leads then to a conclusion that that CFT state is the ordinary CFT vacuum restricted to that patch. If existent, the bulk CFT operators can behave as the ordinary semiclassical quantum field theory in the large-N limit in the weak sense.

  2. Semiclassical Virasoro blocks from AdS3 gravity

    NASA Astrophysics Data System (ADS)

    Hijano, Eliot; Kraus, Per; Perlmutter, Eric; Snively, River

    2015-12-01

    We present a unified framework for the holographic computation of Virasoro conformal blocks at large central charge. In particular, we provide bulk constructions that correctly reproduce all semiclassical Virasoro blocks that are known explicitly from conformal field theory computations. The results revolve around the use of geodesic Witten diagrams, recently introduced in [1], evaluated in locally AdS3 geometries generated by backreaction of heavy operators. We also provide an alternative computation of the heavy-light semiclassical block — in which two external operators become parametrically heavy — as a certain scattering process involving higher spin gauge fields in AdS3; this approach highlights the chiral nature of Virasoro blocks. These techniques may be systematically extended to compute corrections to these blocks and to interpolate amongst the different semiclassical regimes.

  3. Supersymmetric AdS_6 solutions of type IIB supergravity

    NASA Astrophysics Data System (ADS)

    Kim, Hyojoong; Kim, Nakwoo; Suh, Minwoo

    2015-10-01

    We study the general requirement for supersymmetric AdS_6 solutions in type IIB supergravity. We employ the Killing spinor technique and study the differential and algebraic relations among various Killing spinor bilinears to find the canonical form of the solutions. Our result agrees precisely with the work of Apruzzi et al. (JHEP 1411:099, 2014), which used the pure spinor technique. Hoping to identify the geometry of the problem, we also computed four-dimensional theory through the dimensional reduction of type IIB supergravity on AdS_6. This effective action is essentially a non-linear sigma model with five scalar fields parametrizing {SL}(3,{R})/{SO}(2,1), modified by a scalar potential and coupled to Einstein gravity in Euclidean signature. We argue that the scalar potential can be explained by a subgroup CSO(1,1,1) subset {SL}(3,{R}) in a way analogous to gauged supergravity.

  4. Bond-based linear indices of the non-stochastic and stochastic edge-adjacency matrix. 1. Theory and modeling of ChemPhys properties of organic molecules.

    PubMed

    Marrero-Ponce, Yovani; Martnez-Albelo, Eugenio R; Casaola-Martn, Gerardo M; Castillo-Garit, Juan A; Echevera-Daz, Yunaimy; Zaldivar, Vicente Romero; Tygat, Jan; Borges, Jos E Rodriguez; Garca-Domenech, Ramn; Torrens, Francisco; Prez-Gimnez, Facundo

    2010-11-01

    Novel bond-level molecular descriptors are proposed, based on linear maps similar to the ones defined in algebra theory. The kth edge-adjacency matrix (E(k)) denotes the matrix of bond linear indices (non-stochastic) with regard to canonical basis set. The kth stochastic edge-adjacency matrix, ES(k), is here proposed as a new molecular representation easily calculated from E(k). Then, the kth stochastic bond linear indices are calculated using ES(k) as operators of linear transformations. In both cases, the bond-type formalism is developed. The kth non-stochastic and stochastic total linear indices are calculated by adding the kth non-stochastic and stochastic bond linear indices, respectively, of all bonds in molecule. First, the new bond-based molecular descriptors (MDs) are tested for suitability, for the QSPRs, by analyzing regressions of novel indices for selected physicochemical properties of octane isomers (first round). General performance of the new descriptors in this QSPR studies is evaluated with regard to the well-known sets of 2D/3D MDs. From the analysis, we can conclude that the non-stochastic and stochastic bond-based linear indices have an overall good modeling capability proving their usefulness in QSPR studies. Later, the novel bond-level MDs are also used for the description and prediction of the boiling point of 28 alkyl-alcohols (second round), and to the modeling of the specific rate constant (log k), partition coefficient (log P), as well as the antibacterial activity of 34 derivatives of 2-furylethylenes (third round). The comparison with other approaches (edge- and vertices-based connectivity indices, total and local spectral moments, and quantum chemical descriptors as well as E-state/biomolecular encounter parameters) exposes a good behavior of our method in this QSPR studies. Finally, the approach described in this study appears to be a very promising structural invariant, useful not only for QSPR studies but also for similarity/diversity analysis and drug discovery protocols. PMID:20063184

  5. Conserved higher-spin charges in AdS4

    NASA Astrophysics Data System (ADS)

    Gelfond, O. A.; Vasiliev, M. A.

    2016-03-01

    Gauge invariant conserved conformal currents built from massless fields of all spins in 4d Minkowski space-time and AdS4 are described in the unfolded dynamics approach. The current cohomology associated with non-zero conserved charges is found. The resulting list of charges is shown to match the space of parameters of the conformal higher-spin symmetry algebra in four dimensions.

  6. Criteria for fairly allocating scarce health-care resources to genetic tests: which matter most?

    PubMed

    Rogowski, Wolf H; Grosse, Scott D; Schmidtke, Jörg; Marckmann, Georg

    2014-01-01

    The use of genetic tests is expanding rapidly. Given limited health-care budgets throughout Europe and few national coverage decisions specifically for genetic tests, decisions about allocating scarce resources to genetic tests are frequently ad hoc and left to lower-level decision makers. This study assesses substantive ethical and economic criteria to prioritize genetic services in a reasonable and fair manner. Principles for allocating health-care resources can be classified into four categories: need-based allocation; maximizing total benefits; treating people equally; and promoting and rewarding social usefulness. In the face of scarcity, the degree of an individual's need for medical intervention is an important criterion. Also, different economic concepts of efficiency are of relevance in the theory and practice of prioritizing genetic tests. Equity concerns are most likely to be relevant in terms of avoiding undesirable inequities, which may also set boundaries to the use of efficiency as a prioritization criterion. The aim of promoting and rewarding social usefulness is unlikely to be relevant to the question of what priority a genetic test should have in clinical practice. Further work is needed to select an appropriate set of criteria; operationalize them; and assign weights before some kind of standardized priority information can be added to information sources for genetic services. Besides the substantive criteria, formal considerations like those pointed out in the framework of accountability for reasonableness need to be considered in decision making. PMID:23921536

  7. 7 CFR 3430.311 - Allocation of research funds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Allocation of research funds. 3430.311 Section 3430... ADMINISTRATIVE PROVISIONS Agriculture and Food Research Initiative 3430.311 Allocation of research funds. (a) Fundamental research. Of the amount allocated by the Director for research, not less than 60 percent shall...

  8. 7 CFR 3430.311 - Allocation of research funds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Allocation of research funds. 3430.311 Section 3430... ADMINISTRATIVE PROVISIONS Agriculture and Food Research Initiative 3430.311 Allocation of research funds. (a) Fundamental research. Of the amount allocated by the Director for research, not less than 60 percent shall...

  9. 14 CFR 1260.61 - Allocation of risk/liability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Allocation of risk/liability. 1260.61 Section 1260.61 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.61 Allocation of risk/liability. Allocation of...

  10. 14 CFR 1260.61 - Allocation of risk/liability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Allocation of risk/liability. 1260.61 Section 1260.61 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.61 Allocation of risk/liability. Allocation of...

  11. 14 CFR 1260.61 - Allocation of risk/liability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Allocation of risk/liability. 1260.61 Section 1260.61 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.61 Allocation of risk/liability. Allocation of...

  12. 14 CFR 1260.61 - Allocation of risk/liability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Allocation of risk/liability. 1260.61 Section 1260.61 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.61 Allocation of risk/liability. Allocation of...

  13. 12 CFR 211.43 - Allocated transfer risk reserve.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 2 2012-01-01 2012-01-01 false Allocated transfer risk reserve. 211.43 Section... risk reserve. (a) Establishment of Allocated Transfer Risk Reserve. A banking institution shall establish an allocated transfer risk reserve (ATRR) for specified international assets when required by...

  14. 10 CFR 490.703 - Biodiesel fuel use credit allocation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Biodiesel fuel use credit allocation. 490.703 Section 490.703 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.703 Biodiesel fuel use credit allocation. (a) DOE shall allocate to a fleet...

  15. 10 CFR 490.703 - Biodiesel fuel use credit allocation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Biodiesel fuel use credit allocation. 490.703 Section 490.703 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.703 Biodiesel fuel use credit allocation. (a) DOE shall allocate to a fleet...

  16. 10 CFR 490.703 - Biodiesel fuel use credit allocation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Biodiesel fuel use credit allocation. 490.703 Section 490.703 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.703 Biodiesel fuel use credit allocation. (a) DOE shall allocate to a fleet...

  17. Allocating Study Time Appropriately: Spontaneous and Instructed Performance.

    ERIC Educational Resources Information Center

    Dufresne, Annette; And Others

    Two aspects of allocation of study time were examined among 48 third- and 48 fifth-grade children. Aspects examined were: (1) allocation of more time to more difficult material; and (2) allocation of sufficient time to meet a recall goal. Under a self-terminated procedure, children studied two booklets, one of which consisted of easy or highly…

  18. 10 CFR 440.10 - Allocation of funds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Allocation of funds. 440.10 Section 440.10 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION WEATHERIZATION ASSISTANCE FOR LOW-INCOME PERSONS § 440.10 Allocation of funds. (a) DOE shall allocate financial assistance for each State from sums appropriated for any fiscal year, upon annual application. (b)...

  19. 30 CFR 1206.260 - Allocation of washed coal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Allocation of washed coal. 1206.260 Section... INTERIOR Natural Resources Revenue PRODUCT VALUATION Federal Coal § 1206.260 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it...

  20. 30 CFR 206.459 - Allocation of washed coal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Allocation of washed coal. 206.459 Section 206... MANAGEMENT PRODUCT VALUATION Indian Coal § 206.459 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b) When the...

  1. 30 CFR 1206.459 - Allocation of washed coal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Allocation of washed coal. 1206.459 Section... INTERIOR Natural Resources Revenue PRODUCT VALUATION Indian Coal § 1206.459 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it...

  2. 30 CFR 206.260 - Allocation of washed coal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Allocation of washed coal. 206.260 Section 206... MANAGEMENT PRODUCT VALUATION Federal Coal § 206.260 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b) When the...

  3. 77 FR 54482 - Allocation of Costs Under the Simplified Methods

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-05

    ... Internal Revenue Service 26 CFR Part 1 RIN 1545-BG07 Allocation of Costs Under the Simplified Methods... document contains proposed regulations on allocating costs to certain property produced by the taxpayer or... resellers of property that are required to capitalize certain costs to the property and that allocate...

  4. 7 CFR 1470.4 - Allocation and management.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Allocation and management. 1470.4 Section 1470.4 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... Provisions § 1470.4 Allocation and management. (a) The Chief will allocate acres and associated funds...

  5. 7 CFR 1466.5 - National allocation and management.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false National allocation and management. 1466.5 Section 1466.5 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT... PROGRAM General Provisions § 1466.5 National allocation and management. The Chief allocates EQIP funds...

  6. 26 CFR 1.652(b)-3 - Allocation of deductions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Allocation of deductions. 1.652(b)-3 Section 1... (CONTINUED) INCOME TAXES Trusts Which Distribute Current Income Only § 1.652(b)-3 Allocation of deductions... attributable to a specific class of income may be allocated to any item of income (including capital...

  7. 17 CFR 256.01-11 - Methods of allocation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Methods of allocation. 256.01... HOLDING COMPANY ACT OF 1935 General Instructions § 256.01-11 Methods of allocation. Indirect costs and compensation for use of capital shall be allocated to work orders in accordance with the service...

  8. 49 CFR 93.1 - Issuance of aircraft allocations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Issuance of aircraft allocations. 93.1 Section 93.1 Transportation Office of the Secretary of Transportation AIRCRAFT ALLOCATION § 93.1 Issuance of aircraft allocations. From time to time, the Director, Office of Emergency Transportation, issues...

  9. 47 CFR 32.22 - Comprehensive interperiod tax allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Comprehensive interperiod tax allocation. 32.22... interperiod tax allocation. (a) Companies shall apply interperiod tax allocation (tax normalization) to all book/tax temporary differences which would be considered material for published financial...

  10. 47 CFR 2.104 - International Table of Frequency Allocations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false International Table of Frequency Allocations. 2.104 Section 2.104 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL FREQUENCY ALLOCATIONS AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Allocation, Assignment, and Use of Radio Frequencies § 2.104 International Table of...

  11. 10 CFR 490.703 - Biodiesel fuel use credit allocation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Biodiesel fuel use credit allocation. 490.703 Section 490.703 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.703 Biodiesel fuel use credit allocation. (a) DOE shall allocate to a fleet...

  12. 10 CFR 490.703 - Biodiesel fuel use credit allocation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Biodiesel fuel use credit allocation. 490.703 Section 490.703 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.703 Biodiesel fuel use credit allocation. (a) DOE shall allocate to a fleet...

  13. 14 CFR 1260.61 - Allocation of risk/liability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Allocation of risk/liability. 1260.61 Section 1260.61 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.61 Allocation of risk/liability. Allocation of...

  14. 7 CFR 235.4 - Allocation of funds to States.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... programs. (b) Discretionary SAE Funds. For each fiscal year, FNS shall provide the following additional allocations: (1) Allocate $30,000 to each State which administers the Child and Adult Care Food Program (7 CFR.... (a) Nondiscretionary SAE Funds. For each fiscal year, FNS shall allocate the following: (1) To...

  15. 7 CFR 235.4 - Allocation of funds to States.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... programs. (b) Discretionary SAE Funds. For each fiscal year, FNS shall provide the following additional allocations: (1) Allocate $30,000 to each State which administers the Child and Adult Care Food Program (7 CFR.... (a) Nondiscretionary SAE Funds. For each fiscal year, FNS shall allocate the following: (1) To...

  16. Report of the Task Force on Allocations Practices.

    ERIC Educational Resources Information Center

    Shelton, Diana; And Others

    This task force report examines the University of Wyoming's current allocation practices, the allocations themselves, and the expenditure process according to how effectively they support the university library's collection development goals. Individual aspects of the current allocation process are reviewed, including the university budget…

  17. 18 CFR 367.28 - Methods of allocation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Methods of allocation... Instructions § 367.28 Methods of allocation. Indirect costs and compensation for use of capital must be allocated to projects in accordance with the service company's applicable and currently effective methods...

  18. 7 CFR 761.205 - Computing the formula allocation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 7 2011-01-01 2011-01-01 false Computing the formula allocation. 761.205 Section 761.205 Agriculture Regulations of the Department of Agriculture (Continued) FARM SERVICE AGENCY... Funds to State Offices § 761.205 Computing the formula allocation. (a) The formula allocation for FO,...

  19. Reward Allocation among Chinese High School Students in Hong Kong.

    ERIC Educational Resources Information Center

    Chiu, Chi-Yue

    1989-01-01

    Examined effects of personality and performance on reward allocation. Subjects were 89 Hong Kong senior high school students. Results showed that the subjects took into consideration the recipient's personality when they allocated reward to a relatively low performer. Personality was not a factor in allocation of reward to a high performer. (GG)

  20. 47 CFR 64.901 - Allocation of costs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Allocation of costs. 64.901 Section 64.901 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) MISCELLANEOUS RULES RELATING TO COMMON CARRIERS Allocation of Costs § 64.901 Allocation of costs. (a) Carriers required to separate their regulated...

  1. Reward Allocation and Academic versus Social Orientation toward School.

    ERIC Educational Resources Information Center

    Peterson, Candida C.; Peterson, James L.

    1978-01-01

    Correlates 138 elementary school children's views about the purposes of school to their styles of reward allocation: academically motivated students allocated rewards equally to two hypothetical performers who had unequally helped a teacher perform a manual chore, while socially motivated children allocated rewards in an equity (performance-based)…

  2. 24 CFR 92.60 - Allocation amounts for insular areas.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... this section, or for any other reason, HUD may increase the allocation amount for one or more of the... requirements. Funds that become available but which are not used to increase the allocation amount for one or... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Allocation amounts for...

  3. 24 CFR 92.60 - Allocation amounts for insular areas.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... this section, or for any other reason, HUD may increase the allocation amount for one or more of the... requirements. Funds that become available but which are not used to increase the allocation amount for one or... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Allocation amounts for...

  4. 28 CFR 100.14 - Directly allocable costs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... selected so as to permit allocation of the grouping on the basis of the benefits accruing to the multiple... personnel administration within the engineering group). (2) Such allocation necessitates selecting a... not unduly complicate the allocation. (4) Once a methodology for determining an appropriate base...

  5. 49 CFR 93.1 - Issuance of aircraft allocations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Issuance of aircraft allocations. 93.1 Section 93.1 Transportation Office of the Secretary of Transportation AIRCRAFT ALLOCATION § 93.1 Issuance of aircraft allocations. From time to time, the Director, Office of Emergency Transportation, issues...

  6. 49 CFR 93.1 - Issuance of aircraft allocations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Issuance of aircraft allocations. 93.1 Section 93.1 Transportation Office of the Secretary of Transportation AIRCRAFT ALLOCATION § 93.1 Issuance of aircraft allocations. From time to time, the Director, Office of Emergency Transportation, issues...

  7. 49 CFR 93.1 - Issuance of aircraft allocations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Issuance of aircraft allocations. 93.1 Section 93.1 Transportation Office of the Secretary of Transportation AIRCRAFT ALLOCATION § 93.1 Issuance of aircraft allocations. From time to time, the Director, Office of Emergency Transportation, issues...

  8. 49 CFR 93.1 - Issuance of aircraft allocations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Issuance of aircraft allocations. 93.1 Section 93.1 Transportation Office of the Secretary of Transportation AIRCRAFT ALLOCATION § 93.1 Issuance of aircraft allocations. From time to time, the Director, Office of Emergency Transportation, issues...

  9. The Development of a Human Effectiveness Function Allocation Methodology (HEFAM).

    ERIC Educational Resources Information Center

    Connelly, Marilee N.; Willis, Joe E.

    This report was a part of the Human Effectiveness Function Allocation Methodology (HEFAM) project, which is attempting to develop a workable cost-effectiveness methodology for man-machine function allocation. Researchers reviewed the cost-effectiveness and function allocation literature, and interviewed engineers, data analysts, programers,…

  10. 14 CFR 93.215 - Initial allocation of slots.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Initial allocation of slots. 93.215 Section... Carrier IFR Operations at High Density Traffic Airports § 93.215 Initial allocation of slots. (a) Each air... final decisionmaker for initial allocation determinations. (b) Any permanent slot whose use on...

  11. 30 CFR 1206.260 - Allocation of washed coal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Allocation of washed coal. 1206.260 Section... RESOURCES REVENUE PRODUCT VALUATION Federal Coal § 1206.260 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b)...

  12. 30 CFR 1206.459 - Allocation of washed coal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Allocation of washed coal. 1206.459 Section... RESOURCES REVENUE PRODUCT VALUATION Indian Coal § 1206.459 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b)...

  13. 30 CFR 1206.459 - Allocation of washed coal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Allocation of washed coal. 1206.459 Section... RESOURCES REVENUE PRODUCT VALUATION Indian Coal § 1206.459 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b)...

  14. 30 CFR 1206.260 - Allocation of washed coal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Allocation of washed coal. 1206.260 Section... RESOURCES REVENUE PRODUCT VALUATION Federal Coal § 1206.260 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b)...

  15. 30 CFR 1206.459 - Allocation of washed coal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Allocation of washed coal. 1206.459 Section... RESOURCES REVENUE PRODUCT VALUATION Indian Coal § 1206.459 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b)...

  16. 30 CFR 1206.260 - Allocation of washed coal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Allocation of washed coal. 1206.260 Section... RESOURCES REVENUE PRODUCT VALUATION Federal Coal § 1206.260 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b)...

  17. 26 CFR 26.2632-1 - Allocation of GST exemption.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Allocation of GST exemption. 26.2632-1 Section...-1 Allocation of GST exemption. (a) General rule. Except as otherwise provided in this section, an individual or the individual's executor may allocate the individual's $1 million GST exemption at any...

  18. A perceptual optimization of H.264/AVC bit allocation at the frame and macroblock levels

    NASA Astrophysics Data System (ADS)

    Hrarti, M.; Saadane, H.; Larabi, M.-C.; Tamtaoui, A.; Aboutajdine, D.

    2012-01-01

    In H.264/AVC rate control algorithm, the bit allocation process and the QP determination are not optimal. At frame layer, there is an implicit assumption considering that the video sequence is more or less stationary and consequently the neighbouring frames have similar characteristics. So, the target Bit-Rate for each frame is estimated using a straightforward process that allocates an equal bit budget for each frame regardless of its temporal and spatial complexities. This uniform allocation is surely not suited especially for all types of video sequences. The target bits determination at macroblock layer uses the MAD (Mean Absolute Difference) ratio as a complexity measure in order to promote interesting macroblocks, but this measure remains inefficient in handling macroblock characteristics. In a previous work we have proposed Rate-Quantization (R-Q) models for Intra and Inter frames used to deal with the QP determination shortcoming. In this paper, we look to overcome the limitation of the bit allocation process at the frame and the macroblock layers. At the frame level, we enhance the bit allocation process by exploiting frame complexity measures. Thereby, the target bit determination for P-frames is adjusted by combining two temporal measures: The first one is a motion ratio determined from actual bits used to encode previous frames. The second measure exploits both the difference between two consecutive frames and the histogram of this difference. At macroblock level, the visual saliency is used in the bit allocation process. The basic idea is to promote salient macroblocks. Hence, a saliency map, based on a Bottom-Up approach, is generated and a macroblock classification is performed. This classification is then used to accurately adjust UBitsH264 which represents the usual bit budget estimated by H.264/AVC bit allocation process. For salient macroblocks the adjustment leads to a bit budget which is always larger than UBitsH264. The extra bits added to code these macroblocks are deducted from the bit budget allocated to the non-salient macroblocks. Simulations have been carried out using JM15.0 reference software, several video sequences and different target Bit-Rates. In comparison with JM15.0 algorithm, the proposed approach improves the coding efficiency in terms of PSNR/PSNR-HVS (up to +2dB/+3dB). Furthermore, the bandwidth constraint is always satisfied because the actual Bit-Rate is always lower than or equal to the target Bit-Rate.

  19. Quintessence and effective AdS brane geometries

    NASA Astrophysics Data System (ADS)

    Pandey, K. Priyabrat; Singh, Abhishek K.; Singh, Sunita; Kar, Supriya

    2015-04-01

    A geometric torsion dynamics leading to an effective curvature in a second-order formalism on a D4-brane is revisited with a renewed interest. We obtain two effective AdS4 brane geometries on a vacuum created pair of (D{\\bar D})3-brane. One of them is shown to describe an AdS Schwarzschild spinning black hole and the other is shown to describe a spinning black hole bound state. It is argued that a D-instanton in a vacuum created anti-D3-brane within a pair may describe a quintessence. It may seem to incorporate a varying vacuum energy density in a brane universe. We consider the effective curvature scalar on S1 × S1 to analyze torsionless geometries on a vacuum created pair of (D{\\bar D})2-brane. The emergent AdS3 brane is shown to describe a Schwarzschild and a Reissner-Nordstrom (RN) geometries in the presence of extra dimension(s).

  20. Stochastic Methods for Aircraft Design

    NASA Technical Reports Server (NTRS)

    Pelz, Richard B.; Ogot, Madara

    1998-01-01

    The global stochastic optimization method, simulated annealing (SA), was adapted and applied to various problems in aircraft design. The research was aimed at overcoming the problem of finding an optimal design in a space with multiple minima and roughness ubiquitous to numerically generated nonlinear objective functions. SA was modified to reduce the number of objective function evaluations for an optimal design, historically the main criticism of stochastic methods. SA was applied to many CFD/MDO problems including: low sonic-boom bodies, minimum drag on supersonic fore-bodies, minimum drag on supersonic aeroelastic fore-bodies, minimum drag on HSCT aeroelastic wings, FLOPS preliminary design code, another preliminary aircraft design study with vortex lattice aerodynamics, HSR complete aircraft aerodynamics. In every case, SA provided a simple, robust and reliable optimization method which found optimal designs in order 100 objective function evaluations. Perhaps most importantly, from this academic/industrial project, technology has been successfully transferred; this method is the method of choice for optimization problems at Northrop Grumman.

  1. RHIC stochastic cooling motion control

    SciTech Connect

    Gassner, D.; DeSanto, L.; Olsen, R.H.; Fu, W.; Brennan, J.M.; Liaw, CJ; Bellavia, S.; Brodowski, J.

    2011-03-28

    Relativistic Heavy Ion Collider (RHIC) beams are subject to Intra-Beam Scattering (IBS) that causes an emittance growth in all three-phase space planes. The only way to increase integrated luminosity is to counteract IBS with cooling during RHIC stores. A stochastic cooling system for this purpose has been developed, it includes moveable pick-ups and kickers in the collider that require precise motion control mechanics, drives and controllers. Since these moving parts can limit the beam path aperture, accuracy and reliability is important. Servo, stepper, and DC motors are used to provide actuation solutions for position control. The choice of motion stage, drive motor type, and controls are based on needs defined by the variety of mechanical specifications, the unique performance requirements, and the special needs required for remote operations in an accelerator environment. In this report we will describe the remote motion control related beam line hardware, position transducers, rack electronics, and software developed for the RHIC stochastic cooling pick-ups and kickers.

  2. Stochastic models of viral infection

    NASA Astrophysics Data System (ADS)

    Chou, Tom

    2009-03-01

    We develop biophysical models of viral infections from a stochastic process perspective. The entry of enveloped viruses is treated as a stochastic multiple receptor and coreceptor engagement process that can lead to membrane fusion or endocytosis. The probabilities of entry via fusion and endocytosis are computed as functions of the receptor/coreceptor engagement rates. Since membrane fusion and endocytosis entry pathways can lead to very different infection outcomes, we delineate the parameter regimes conducive to each entry pathway. After entry, viral material is biochemically processed and degraded as it is transported towards the nucleus. Productive infections occur only when the material reaches the nucleus in the proper biochemical state. Thus, entry into the nucleus in an infectious state requires the proper timing of the cytoplasmic transport process. We compute the productive infection probability and show its nonmonotonic dependence on both transport speeds and biochemical transformation rates. Our results carry subtle consequences on the dosage and efficacy of antivirals such as reverse transcription inhibitors.

  3. Stochastic models for cell division

    NASA Astrophysics Data System (ADS)

    Stukalin, Evgeny; Sun, Sean

    2013-03-01

    The probability of cell division per unit time strongly depends of age of cells, i.e., time elapsed since their birth. The theory of cell populations in the age-time representation is systematically applied for modeling cell division for different spreads in generation times. We use stochastic simulations to address the same issue at the level of individual cells. Our approach unlike deterministic theory enables to analyze the size fluctuations of cell colonies at different growth conditions (in the absence and in the presence of cell death, for initially synchronized and asynchronous cell populations, for conditions of restricted growth). We find the simple quantitative relation between the asymptotic values of relative size fluctuations around mean values for initially synchronized cell populations under growth and the coefficients of variation of generation times. Effect of initial age distribution for asynchronous growth of cell cultures is also studied by simulations. The influence of constant cell death on fluctuations of sizes of cell populations is found to be essential even for small cell death rates, i.e., for realistic growth conditions. The stochastic model is generalized for biologically relevant case that involves both cell reproduction and cell differentiation.

  4. Interrupted monitoring of a stochastic process

    NASA Technical Reports Server (NTRS)

    Palmer, E.

    1977-01-01

    Normative strategies are developed for tasks where the pilot must interrupt his monitoring of a stochastic process in order to attend to other duties. Results are given as to how characteristics of the stochastic process and the other tasks affect the optimal strategies. The optimum strategy is also compared to the strategies used by subjects in a pilot experiment.

  5. Stochastic Modeling of Laminar-Turbulent Transition

    NASA Technical Reports Server (NTRS)

    Rubinstein, Robert; Choudhari, Meelan

    2002-01-01

    Stochastic versions of stability equations are developed in order to develop integrated models of transition and turbulence and to understand the effects of uncertain initial conditions on disturbance growth. Stochastic forms of the resonant triad equations, a high Reynolds number asymptotic theory, and the parabolized stability equations are developed.

  6. Seasonal long-memory stochastic volatility

    NASA Astrophysics Data System (ADS)

    Gonzaga, Alex C.

    2013-10-01

    In this paper, we propose an alternative approach to estimation of seasonal long-memory stochastic volatility based on the generalized long-memory stochastic volatility (GLMSV) model. We show that the estimator is consistent. We investigate the small sample performance of the estimator by simulation. An application to actual data is also presented.

  7. On Behavior of Stochastic Synchronization Models

    NASA Astrophysics Data System (ADS)

    Manita, Anatoly

    2016-02-01

    We consider N-component synchronization models defined in terms of stochastic particle systems with special interaction. For general (nonsymmetric) Markov models we discuss phenomenon of the long time stochastic synchronization. We study behavior of the system in different limit situations related to appropriate changes of variables and scalings. For N = 2 limit distributions are found explicitly.

  8. From Complex to Simple: Interdisciplinary Stochastic Models

    ERIC Educational Resources Information Center

    Mazilu, D. A.; Zamora, G.; Mazilu, I.

    2012-01-01

    We present two simple, one-dimensional, stochastic models that lead to a qualitative understanding of very complex systems from biology, nanoscience and social sciences. The first model explains the complicated dynamics of microtubules, stochastic cellular highways. Using the theory of random walks in one dimension, we find analytical expressions

  9. From Complex to Simple: Interdisciplinary Stochastic Models

    ERIC Educational Resources Information Center

    Mazilu, D. A.; Zamora, G.; Mazilu, I.

    2012-01-01

    We present two simple, one-dimensional, stochastic models that lead to a qualitative understanding of very complex systems from biology, nanoscience and social sciences. The first model explains the complicated dynamics of microtubules, stochastic cellular highways. Using the theory of random walks in one dimension, we find analytical expressions…

  10. Bunched Beam Stochastic Cooling and Coherent Lines

    SciTech Connect

    Blaskiewicz, M.; Brennan, J. M.

    2006-03-20

    Strong coherent signals complicate bunched beam stochastic cooling, and development of the longitudinal stochastic cooling system for RHIC required dealing with coherence in heavy ion beams. Studies with proton beams revealed additional forms of coherence. This paper presents data and analysis for both sorts of beams.

  11. Attainability analysis in stochastic controlled systems

    SciTech Connect

    Ryashko, Lev

    2015-03-10

    A control problem for stochastically forced nonlinear continuous-time systems is considered. We propose a method for construction of the regulator that provides a preassigned probabilistic distribution of random states in stochastic equilibrium. Geometric criteria of the controllability are obtained. Constructive technique for the specification of attainability sets is suggested.

  12. Research of Stochastic Robustness: Results and conclusions

    NASA Technical Reports Server (NTRS)

    Marrison, Chris

    1995-01-01

    With stochastic robustness we are creating tools to design robust compensators for practical systems. During this year, the stochastic robustness research achieved the following results: refined the search tools needed for synthesis; successfully designed robust compensators for the American Controls Conference benchmark problem; and successfully designed robust compensators for a nonlinear hypersonic aircraft model with uncertainties in 28 parameters.

  13. Cost Allocation in Water Resources Development

    NASA Astrophysics Data System (ADS)

    Young, H. P.; Okada, N.; Hashimoto, T.

    1982-06-01

    Different methods for allocating the joint costs of water supply projects among users are compared on the basis of certain commonsense principles of equity. We contrast the separable costs-remaining benefits (SCRB) method with simple proportional allocation schemes and more sophisticated methods from cooperative game theory, including the Shapley value and variants of the core. Advantages and disadvantages of the methods in practice are examined using a regional water supply system in Sweden. It is argued that these principles provide a useful framework for choosing intelligently among methods. The appropriateness of a method depends on the context, especially on the reliability of information about costs and demands. The conclusion is that there is no one best method, although from a normative standpoint the SCRB method may be one of the worst.

  14. The relationship between attention allocation and cheating.

    PubMed

    Pittarello, Andrea; Motro, Daphna; Rubaltelli, Enrico; Pluchino, Patrik

    2016-04-01

    Little is known about the relationship between attention allocation and dishonesty. The goal of the present work was to address this issue using the eyetracking methodology. We developed a novel task in which participants could honestly report seeing a particular card and lose money, or they could falsely report not seeing the card and not lose money. When participants cheated, they allocated less attention (i.e., shorter fixation durations and fewer fixations) to the card than when they behaved honestly. Our results suggest that when dishonesty pays, shifting attention away from undesirable information can serve as a self-deception strategy that allows individuals to serve their self-interests while maintaining a positive self-concept. PMID:26340847

  15. Traffic resource allocation for complex networks

    NASA Astrophysics Data System (ADS)

    Ling, Xiang; Hu, Mao-Bin; Long, Jian-Cheng; Ding, Jian-Xun; Shi, Qin

    2013-01-01

    In this paper, an optimal resource allocation strategy is proposed to enhance traffic dynamics in complex networks. The network resources are the total node packet-delivering capacity and the total link bandwidth. An analytical method is developed to estimate the overall network capacity by using the concept of efficient betweenness (ratio of algorithmic betweenness and local processing capacity). Three network structures (scale-free, small-world, and random networks) and two typical routing protocols (shortest path protocol and efficient routing protocol) are adopted to demonstrate the performance of the proposed strategy. Our results show that the network capacity is reversely proportional to the average path length for a particular routing protocol and the shortest path protocol can achieve the largest network capacity when the proposed resource allocation strategy is adopted.

  16. Key Programmes on La Silla: First Allocations

    NASA Astrophysics Data System (ADS)

    van der Laan, H.

    1989-03-01

    With the Observing Programmes Committee's recommendations in hand, early December last year, all information was available to allocate and plan the observations for Period 43 (normal programmes) and Periods 43 and 44 (Key Programmes). The scenario of preparations and decisions has precisely followed the intentions outlined in my original article in the Messenger of March 1988 (No. 51). Here the community is briefly informed about the procedures, the proposals and the allocations. Investigators of Key Programme Proposals successful in this first round will themselves describe their research plans in brief Messenger articles, starting with three such contributions in this issue and to be continued. Later in this article there is an overview of Key Programme time committed and time expected to be available for subsequent rounds, with the 15th of October 1989 as the next deadline.

  17. Dynamic advance reservation with delayed allocation

    SciTech Connect

    Vokkarane, Vinod; Somani, Arun

    2014-12-02

    A method of scheduling data transmissions from a source to a destination, includes the steps of: providing a communication system having a number of channels and a number of paths, each of the channels having a plurality of designated time slots; receiving two or more data transmission requests; provisioning the transmission of the data; receiving data corresponding to at least one of the two or more data transmission requests; waiting until an earliest requested start time T.sub.s; allocating at the current time each of the two or more data transmission requests; transmitting the data; and repeating the steps of waiting, allocating, and transmitting until each of the two or more data transmission requests that have been provisioned for a transmission of data is satisfied. A system to perform the method of scheduling data transmissions is also described.

  18. Energy uptake and allocation during ontogeny.

    PubMed

    Hou, Chen; Zuo, Wenyun; Moses, Melanie E; Woodruff, William H; Brown, James H; West, Geoffrey B

    2008-10-31

    All organisms face the problem of how to fuel ontogenetic growth. We present a model, empirically grounded in data from birds and mammals, that correctly predicts how growing animals allocate food energy between synthesis of new biomass and maintenance of existing biomass. Previous energy budget models have typically had their bases in rates of either food consumption or metabolic energy expenditure. Our model provides a framework that reconciles these two approaches and highlights the fundamental principles that determine rates of food assimilation and rates of energy allocation to maintenance, biosynthesis, activity, and storage. The model predicts that growth and assimilation rates for all animals should cluster closely around two universal curves. Data for mammals and birds of diverse body sizes and taxa support these predictions. PMID:18974352

  19. A Framework for Incorporating General Domain Knowledge into Latent Dirichlet Allocation using First-Order Logic

    SciTech Connect

    Andrzejewski, D; Zhu, X; Craven, M; Recht, B

    2011-01-18

    Topic models have been used successfully for a variety of problems, often in the form of application-specific extensions of the basic Latent Dirichlet Allocation (LDA) model. Because deriving these new models in order to encode domain knowledge can be difficult and time-consuming, we propose the Fold-all model, which allows the user to specify general domain knowledge in First-Order Logic (FOL). However, combining topic modeling with FOL can result in inference problems beyond the capabilities of existing techniques. We have therefore developed a scalable inference technique using stochastic gradient descent which may also be useful to the Markov Logic Network (MLN) research community. Experiments demonstrate the expressive power of Fold-all, as well as the scalability of our proposed inference method.

  20. Assessing the performance of life-cycle portfolio allocation strategies for retirement saving: a simulation study.

    PubMed

    Bridges, Benjamin; Gesumaria, Robert; Leonesio, Michael V

    2010-01-01

    This article examines the performance of four life-cycle portfolio allocation strategies through stochastic simulation based on observed U.S. asset returns during 1926-2008. Annual worker contributions to retirement savings accounts are based on the actual lifetime earnings histories maintained by the Social Security Administration for 12,871 workers born during 1915-1942. Each strategy's performance is evaluated primarily on the basis of the distributions of internal rates of return on investments calculated at the time of retirement. Comparisons are made with the performance of four other investment strategies that vary in terms of their exposure to stock and bond market risk. Life-cycle plans with larger portfolio weights assigned to equities have higher average returns, but those gains come at the cost of increased risk of infrequent bad outcomes. PMID:20337136

  1. Rethinking reinforcement: allocation, induction, and contingency.

    PubMed

    Baum, William M

    2012-01-01

    The concept of reinforcement is at least incomplete and almost certainly incorrect. An alternative way of organizing our understanding of behavior may be built around three concepts: allocation, induction, and correlation. Allocation is the measure of behavior and captures the centrality of choice: All behavior entails choice and consists of choice. Allocation changes as a result of induction and correlation. The term induction covers phenomena such as adjunctive, interim, and terminal behavior-behavior induced in a situation by occurrence of food or another Phylogenetically Important Event (PIE) in that situation. Induction resembles stimulus control in that no one-to-one relation exists between induced behavior and the inducing event. If one allowed that some stimulus control were the result of phylogeny, then induction and stimulus control would be identical, and a PIE would resemble a discriminative stimulus. Much evidence supports the idea that a PIE induces all PIE-related activities. Research also supports the idea that stimuli correlated with PIEs become PIE-related conditional inducers. Contingencies create correlations between "operant" activity (e.g., lever pressing) and PIEs (e.g., food). Once an activity has become PIE-related, the PIE induces it along with other PIE-related activities. Contingencies also constrain possible performances. These constraints specify feedback functions, which explain phenomena such as the higher response rates on ratio schedules in comparison with interval schedules. Allocations that include a lot of operant activity are "selected" only in the sense that they generate more frequent occurrence of the PIE within the constraints of the situation; contingency and induction do the "selecting." PMID:22287807

  2. Rethinking Reinforcement: Allocation, Induction, and Contingency

    PubMed Central

    Baum, William M

    2012-01-01

    The concept of reinforcement is at least incomplete and almost certainly incorrect. An alternative way of organizing our understanding of behavior may be built around three concepts: allocation, induction, and correlation. Allocation is the measure of behavior and captures the centrality of choice: All behavior entails choice and consists of choice. Allocation changes as a result of induction and correlation. The term induction covers phenomena such as adjunctive, interim, and terminal behavior—behavior induced in a situation by occurrence of food or another Phylogenetically Important Event (PIE) in that situation. Induction resembles stimulus control in that no one-to-one relation exists between induced behavior and the inducing event. If one allowed that some stimulus control were the result of phylogeny, then induction and stimulus control would be identical, and a PIE would resemble a discriminative stimulus. Much evidence supports the idea that a PIE induces all PIE-related activities. Research also supports the idea that stimuli correlated with PIEs become PIE-related conditional inducers. Contingencies create correlations between “operant” activity (e.g., lever pressing) and PIEs (e.g., food). Once an activity has become PIE-related, the PIE induces it along with other PIE-related activities. Contingencies also constrain possible performances. These constraints specify feedback functions, which explain phenomena such as the higher response rates on ratio schedules in comparison with interval schedules. Allocations that include a lot of operant activity are “selected” only in the sense that they generate more frequent occurrence of the PIE within the constraints of the situation; contingency and induction do the “selecting.” PMID:22287807

  3. Irrational time allocation in decision-making.

    PubMed

    Oud, Bastiaan; Krajbich, Ian; Miller, Kevin; Cheong, Jin Hyun; Botvinick, Matthew; Fehr, Ernst

    2016-01-13

    Time is an extremely valuable resource but little is known about the efficiency of time allocation in decision-making. Empirical evidence suggests that in many ecologically relevant situations, decision difficulty and the relative reward from making a correct choice, compared to an incorrect one, are inversely linked, implying that it is optimal to use relatively less time for difficult choice problems. This applies, in particular, to value-based choices, in which the relative reward from choosing the higher valued item shrinks as the values of the other options get closer to the best option and are thus more difficult to discriminate. Here, we experimentally show that people behave sub-optimally in such contexts. They do not respond to incentives that favour the allocation of time to choice problems in which the relative reward for choosing the best option is high; instead they spend too much time on problems in which the reward difference between the options is low. We demonstrate this by showing that it is possible to improve subjects' time allocation with a simple intervention that cuts them off when their decisions take too long. Thus, we provide a novel form of evidence that organisms systematically spend their valuable time in an inefficient way, and simultaneously offer a potential solution to the problem. PMID:26763695

  4. Resource allocation models of auditory working memory.

    PubMed

    Joseph, Sabine; Teki, Sundeep; Kumar, Sukhbinder; Husain, Masud; Griffiths, Timothy D

    2016-06-01

    Auditory working memory (WM) is the cognitive faculty that allows us to actively hold and manipulate sounds in mind over short periods of time. We develop here a particular perspective on WM for non-verbal, auditory objects as well as for time based on the consideration of possible parallels to visual WM. In vision, there has been a vigorous debate on whether WM capacity is limited to a fixed number of items or whether it represents a limited resource that can be allocated flexibly across items. Resource allocation models predict that the precision with which an item is represented decreases as a function of total number of items maintained in WM because a limited resource is shared among stored objects. We consider here auditory work on sequentially presented objects of different pitch as well as time intervals from the perspective of dynamic resource allocation. We consider whether the working memory resource might be determined by perceptual features such as pitch or timbre, or bound objects comprising multiple features, and we speculate on brain substrates for these behavioural models. This article is part of a Special Issue entitled SI: Auditory working memory. PMID:26835560

  5. Optimal allocation of trend following strategies

    NASA Astrophysics Data System (ADS)

    Grebenkov, Denis S.; Serror, Jeremy

    2015-09-01

    We consider a portfolio allocation problem for trend following (TF) strategies on multiple correlated assets. Under simplifying assumptions of a Gaussian market and linear TF strategies, we derive analytical formulas for the mean and variance of the portfolio return. We construct then the optimal portfolio that maximizes risk-adjusted return by accounting for inter-asset correlations. The dynamic allocation problem for n assets is shown to be equivalent to the classical static allocation problem for n2 virtual assets that include lead-lag corrections in positions of TF strategies. The respective roles of asset auto-correlations and inter-asset correlations are investigated in depth for the two-asset case and a sector model. In contrast to the principle of diversification suggesting to treat uncorrelated assets, we show that inter-asset correlations allow one to estimate apparent trends more reliably and to adjust the TF positions more efficiently. If properly accounted for, inter-asset correlations are not deteriorative but beneficial for portfolio management that can open new profit opportunities for trend followers. These concepts are illustrated using daily returns of three highly correlated futures markets: the E-mini S&P 500, Euro Stoxx 50 index, and the US 10-year T-note futures.

  6. Impact of deterministic and stochastic updates on network reciprocity in the prisoner's dilemma game.

    PubMed

    Tanimoto, Jun

    2014-08-01

    In 2 × 2 prisoner's dilemma games, network reciprocity is one mechanism for adding social viscosity, which leads to cooperative equilibrium. This study introduced an intriguing framework for the strategy update rule that allows any combination of a purely deterministic method, imitation max (IM), and a purely probabilistic one, pairwise Fermi (Fermi-PW). A series of simulations covering the whole range from IM to Fermi-PW reveals that, as a general tendency, the larger fractions of stochastic updating reduce network reciprocity, so long as the underlying lattice contains no noise in the degree of distribution. However, a small amount of stochastic flavor added to an otherwise perfectly deterministic update rule was actually found to enhance network reciprocity. This occurs because a subtle stochastic effect in the update rule improves the evolutionary trail in games having more stag-hunt-type dilemmas, although the same stochastic effect degenerates evolutionary trails in games having more chicken-type dilemmas. We explain these effects by dividing evolutionary trails into the enduring and expanding periods defined by Shigaki et al. [Phys. Rev. E 86, 031141 (2012)]. PMID:25215687

  7. Impact of deterministic and stochastic updates on network reciprocity in the prisoner's dilemma game

    NASA Astrophysics Data System (ADS)

    Tanimoto, Jun

    2014-08-01

    In 2 × 2 prisoner's dilemma games, network reciprocity is one mechanism for adding social viscosity, which leads to cooperative equilibrium. This study introduced an intriguing framework for the strategy update rule that allows any combination of a purely deterministic method, imitation max (IM), and a purely probabilistic one, pairwise Fermi (Fermi-PW). A series of simulations covering the whole range from IM to Fermi-PW reveals that, as a general tendency, the larger fractions of stochastic updating reduce network reciprocity, so long as the underlying lattice contains no noise in the degree of distribution. However, a small amount of stochastic flavor added to an otherwise perfectly deterministic update rule was actually found to enhance network reciprocity. This occurs because a subtle stochastic effect in the update rule improves the evolutionary trail in games having more stag-hunt-type dilemmas, although the same stochastic effect degenerates evolutionary trails in games having more chicken-type dilemmas. We explain these effects by dividing evolutionary trails into the enduring and expanding periods defined by Shigaki et al. [Phys. Rev. E 86, 031141 (2012), 10.1103/PhysRevE.86.031141].

  8. Deterministic and stochastic bifurcations in the Hindmarsh-Rose neuronal model

    NASA Astrophysics Data System (ADS)

    Dtchetgnia Djeundam, S. R.; Yamapi, R.; Kofane, T. C.; Aziz-Alaoui, M. A.

    2013-09-01

    We analyze the bifurcations occurring in the 3D Hindmarsh-Rose neuronal model with and without random signal. When under a sufficient stimulus, the neuron activity takes place; we observe various types of bifurcations that lead to chaotic transitions. Beside the equilibrium solutions and their stability, we also investigate the deterministic bifurcation. It appears that the neuronal activity consists of chaotic transitions between two periodic phases called bursting and spiking solutions. The stochastic bifurcation, defined as a sudden change in character of a stochastic attractor when the bifurcation parameter of the system passes through a critical value, or under certain condition as the collision of a stochastic attractor with a stochastic saddle, occurs when a random Gaussian signal is added. Our study reveals two kinds of stochastic bifurcation: the phenomenological bifurcation (P-bifurcations) and the dynamical bifurcation (D-bifurcations). The asymptotical method is used to analyze phenomenological bifurcation. We find that the neuronal activity of spiking and bursting chaos remains for finite values of the noise intensity.

  9. Technical efficiency and resources allocation in university hospitals in Tehran, 2009-2012

    PubMed Central

    Rezapour, Aziz; Ebadifard Azar, Farbod; Yousef Zadeh, Negar; Roumiani, YarAllah; Bagheri Faradonbeh, Saeed

    2015-01-01

    Background: Assessment of hospitals’ performance in achieving its goals is a basic necessity. Measuring the efficiency of hospitals in order to boost resource productivity in healthcare organizations is extremely important. The aim of this study was to measure technical efficiency and determining status of resource allocation in some university hospitals, in Tehran, Iran. Methods: This study was conducted in 2012; the research population consisted of all hospitals affiliated to Iran and Tehran medical sciences universities of. Required data, such as human and capital resources information and also production variables (hospital outputs) were collected from data centers of studied hospitals. Data were analyzed using data envelopment analysis (DEA) method, Deap2,1 software; and the stochastic frontier analysis (SFA) method, Frontier 4,1 software. Results: According to DEA method, average of technical, management (pure) and scale efficiency of the studied hospitals during the study period were calculated 0.87, 0.971, and 0.907, respectively. All kinds of efficiency did not follow a fixed trend over the study time and were constantly changing. In the stochastic frontier's production function analysis, the technical efficiency of the studied industry during the study period was estimated to be 0.389. Conclusion: This study represented hospitals with the highest and lowest efficiency. Reference hospitals (more efficient states) were indicated for the inefficient centers. According to the findings, it was found that in the hospitals that do not operate efficiently, there is a capacity to improve the technical efficiency by removing excess inputs without changes in the level of outputs. However, by the optimal allocation of resources in most studied hospitals, very important economy of scale can be achieved. PMID:26793657

  10. ADS/CFT and QCD

    SciTech Connect

    Brodsky, Stanley J.; de Teramond, Guy F.; /Costa Rica U. /SLAC

    2007-02-21

    The AdS/CFT correspondence between string theory in AdS space and conformal .eld theories in physical spacetime leads to an analytic, semi-classical model for strongly-coupled QCD which has scale invariance and dimensional counting at short distances and color confinement at large distances. Although QCD is not conformally invariant, one can nevertheless use the mathematical representation of the conformal group in five-dimensional anti-de Sitter space to construct a first approximation to the theory. The AdS/CFT correspondence also provides insights into the inherently non-perturbative aspects of QCD, such as the orbital and radial spectra of hadrons and the form of hadronic wavefunctions. In particular, we show that there is an exact correspondence between the fifth-dimensional coordinate of AdS space z and a specific impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron in ordinary space-time. This connection allows one to compute the analytic form of the frame-independent light-front wavefunctions, the fundamental entities which encode hadron properties and allow the computation of decay constants, form factors, and other exclusive scattering amplitudes. New relativistic lightfront equations in ordinary space-time are found which reproduce the results obtained using the 5-dimensional theory. The effective light-front equations possess remarkable algebraic structures and integrability properties. Since they are complete and orthonormal, the AdS/CFT model wavefunctions can also be used as a basis for the diagonalization of the full light-front QCD Hamiltonian, thus systematically improving the AdS/CFT approximation.

  11. AD-1 aircraft in flight

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The Ames-Dryden (AD)-1 was a research aircraft designed to investigate the concept of an oblique (or pivoting) wing. The movie clip runs about 17 seconds and has two air-to-air views of the AD-1. The first shot is from slightly above as the wing pivots to 60 degrees. The other angle is almost directly below the aircraft when the wing is fully pivoted.

  12. Added sugars and micronutrient dilution.

    PubMed

    Livingstone, M B E; Rennie, K L

    2009-03-01

    There is increasing concern that high intakes of added sugars promote micronutrient dilution. However, the overall conclusion to emerge from the existing evidence base is that associations between reported intakes of added sugars and intakes of micronutrients are inconsistent and often non-linear, both across and within age groups, and between the genders. If a nutrient displacement effect does exist, a high consumption of added sugar does not necessarily compromise overall micronutrient intakes and similarly, consuming less added sugar is no guarantee that micronutrient intakes will be optimized. Clarification of this issue has been beset by methodological and conceptual difficulties. The observed associations between added sugars and micronutrient intake have been heavily contingent on both the definition of sugars chosen and the analytical approach used for adjusting for differences in reported energy intake. These issues have been further compounded by mis-reporting of food intake of unknown direction and magnitude and the cut-offs used to determine 'inadequate' micronutrient intakes which vary over time and between studies and countries. In the absence compelling evidence that micronutrient intakes are compromised by a high consumption of added sugars, it may now be appropriate to question the legitimacy of the nutrient dilution hypothesis as it is highly likely that it is oversimplifying more subtle and complex dietary issues. Recommendations for further research are made to help bring resolution to these issues. PMID:19207534

  13. Stochastic Water Quality Optimization Using Imbedded Chance Constraints

    NASA Astrophysics Data System (ADS)

    Ellis, J. Hugh

    1987-12-01

    A chance-constrained stochastic programming model is developed for water quality optimization. It determines the least cost allocation of waste treatment plant biochemical oxygen demand (BOD) removal efficiencies, subject to probabilistic restrictions on maximum allowable instream dissolved oxygen deficit. The new model extends well beyond traditional approaches that assume streamflow is the sole random variable. In addition to streamflow, other random variables in the model are initial in-stream BOD level and dissolved oxygen (DO) deficit; waste outfall flow rates, BOD levels and DO deficits; deoxygenation k1, reaeration k2, and sedimentation-scour rate k3 coefficients of the Streeter-Phelps DO sag model; photosynthetic input-benthic depletion rates Ai, and nonpoint source BOD input rate Pi for the Camp-Dobbins extensions to the Streeter-Phelps model. These random variables appear in more highly aggregated terms which in turn form part of the probabilistic constraints of the water quality optimization model. Stochastic simulation procedures for estimating the probability density functions and covariances of these aggregated terms are discussed. A new chance-constrained programming variant, imbedded chance constraints, is presented along with an example application. In effect, this method imbeds a chance constraint within a chance constraint in a manner which is loosely associated with the distribution-free method of chance-constrained programming. It permits the selection of nonexpected value realizations of the mean and variance estimates employed in the deterministic equivalents of traditional chance-constrained models. As well, it provides a convenient mechanism for generating constraint probability response surfaces. A joint chance-constrained formulation is also presented which illustrates the possibility for prescription of an overall system reliability level, rather than reach-by-reach reliability assignment.

  14. Final Technical Report - Stochastic Nonlinear Data-Reduction Methods with Detection and Prediction of Critical Rare Event

    SciTech Connect

    Karniadakis, George Em; Vanden-Eijnden, Eric; Lin, Guang; Wan, Xiaoliang

    2013-04-03

    In this project, the collective efforts of all co-PIs aim to address three current limitations in modeling stochastic systems: (1) the inputs are mostly based on ad hoc models, (2) the number of independent parameters is very high, and (3) rare and critical events are difficult to capture with existing algorithms

  15. Barmah-Millewa forest environmental water allocation.

    PubMed

    Stewart, G; Harper, B

    2002-01-01

    The formal allocation of water for the environment is a developing area of river management both scientifically and in terms of community participation. This case study, illustrating the recent use of the Barmah-Millewa Forest Environmental Water Allocation (EWA), provides a practical demonstration of community participation in environmental water management, the application of hydrological and biological "triggers" and a positive, demonstrable biological outcome from an environmental water allocation. The Barmah-Millewa Forest covers an area of 70,000 ha across the floodplain of the Murray River, upstream of the town of Echuca. About half the forest is in NSW (Millewa) and half is in Victoria (Barmah). The Barmah Forest is a Wetland of International Importance listed under the Convention on Wetlands - Ramsar Convention. The forest is the largest river redgum forest in the world. The natural flooding cycle associated with the forest has been significantly altered by regulation of the Murray River--impacting upon the overall health of the forest ecosystem. Recognising this, the Murray Darling Basin Commission developed a water management strategy for the forest to enhance forest, fish and wildlife values. To implement this strategy, between 1990 and 1993 reports were completed and community consultation took place. In 1993 the Murray Darling Basin Ministerial Council approved allocation of 100 Gigalitres of water per year, provided in equal shares by NSW and Victoria, to meet the needs of the forest ecosystem and in 1994 the Barmah-Millewa Forum was established under the Murray-Darling Basin Agreement. The vision for the Forum is to maintain and, where possible, improve the ecological and productive sustainability of the Barmah-Millewa Forest and to establish a planning and operational framework to better meet the flooding and drying requirements of the riparian forests and wetlands. Between October 2000 and January 2001 the Barmah-Millewa Forest Environmental Water Allocation was used for the second time. A total of 341 GL was released as an EWA. This amount represented only 8% of the total flows downstream of Yarrawonga Weir from September 2000 and January 2001. The strategic use of the relatively small amount of water enabled flooding to be maintained and ensured significant breeding success for water birds and other biota in the Forest. PMID:12171356

  16. Stochastic models of neuronal dynamics.

    PubMed

    Harrison, L M; David, O; Friston, K J

    2005-05-29

    Cortical activity is the product of interactions among neuronal populations. Macroscopic electrophysiological phenomena are generated by these interactions. In principle, the mechanisms of these interactions afford constraints on biologically plausible models of electrophysiological responses. In other words, the macroscopic features of cortical activity can be modelled in terms of the microscopic behaviour of neurons. An evoked response potential (ERP) is the mean electrical potential measured from an electrode on the scalp, in response to some event. The purpose of this paper is to outline a population density approach to modelling ERPs. We propose a biologically plausible model of neuronal activity that enables the estimation of physiologically meaningful parameters from electrophysiological data. The model encompasses four basic characteristics of neuronal activity and organization: (i) neurons are dynamic units, (ii) driven by stochastic forces, (iii) organized into populations with similar biophysical properties and response characteristics and (iv) multiple populations interact to form functional networks. This leads to a formulation of population dynamics in terms of the Fokker-Planck equation. The solution of this equation is the temporal evolution of a probability density over state-space, representing the distribution of an ensemble of trajectories. Each trajectory corresponds to the changing state of a neuron. Measurements can be modelled by taking expectations over this density, e.g. mean membrane potential, firing rate or energy consumption per neuron. The key motivation behind our approach is that ERPs represent an average response over many neurons. This means it is sufficient to model the probability density over neurons, because this implicitly models their average state. Although the dynamics of each neuron can be highly stochastic, the dynamics of the density is not. This means we can use Bayesian inference and estimation tools that have already been established for deterministic systems. The potential importance of modelling density dynamics (as opposed to more conventional neural mass models) is that they include interactions among the moments of neuronal states (e.g. the mean depolarization may depend on the variance of synaptic currents through nonlinear mechanisms).Here, we formulate a population model, based on biologically informed model-neurons with spike-rate adaptation and synaptic dynamics. Neuronal sub-populations are coupled to form an observation model, with the aim of estimating and making inferences about coupling among sub-populations using real data. We approximate the time-dependent solution of the system using a bi-orthogonal set and first-order perturbation expansion. For didactic purposes, the model is developed first in the context of deterministic input, and then extended to include stochastic effects. The approach is demonstrated using synthetic data, where model parameters are identified using a Bayesian estimation scheme we have described previously. PMID:16087449

  17. Ultraviolet asymptotics and singular dynamics of AdS perturbations

    NASA Astrophysics Data System (ADS)

    Craps, Ben; Evnin, Oleg; Vanhoof, Joris

    2015-10-01

    Important insights into the dynamics of spherically symmetric AdS-scalar field perturbations can be obtained by considering a simplified time-averaged theory accurately describing perturbations of amplitude ɛ on time-scales of order 1/ ɛ 2. The coefficients of the time-averaged equations are complicated expressions in terms of the AdS scalar field mode functions, which are in turn related to the Jacobi polynomials. We analyze the behavior of these coefficients for high frequency modes. The resulting asymptotics can be useful for understanding the properties of the finite-time singularity in solutions of the time-averaged theory recently reported in the literature. We highlight, in particular, the gauge dependence of this asymptotics, with respect to the two most commonly used gauges. The harsher growth of the coefficients at large frequencies in higher-dimensional AdS suggests strengthening of turbulent instabilities in higher dimensions. In the course of our derivations, we arrive at recursive relations for the coefficients of the time-averaged theory that are likely to be useful for evaluating them more efficiently in numerical simulations.

  18. Postural Stability in Parkinson's Disease Patients Is Improved after Stochastic Resonance Therapy

    PubMed Central

    Kaut, Oliver; Brenig, Daniel; Marek, Milena; Allert, Niels; Wüllner, Ullrich

    2016-01-01

    Background. Postural instability in Parkinson's disease (PD) increases the risk of falls and is not improved by pharmacological therapy. Objective. We performed a double-blind, randomized sham-controlled study to test the effects of stochastic resonance (whole body vibration) therapy on postural stability in PD. Methods. Fifty-six PD participants were allocated to either experimental or sham groups. The experimental group received four series of vibration over eight days, with each series consisting of six stimulus trains of 60-second duration using a randomized whole body vibration. Participants allocated to the control group received a sham treatment. Results. Within-group analysis revealed that postural stability in the experimental group improved by 17.5% (p = 0.005) comparing experimental and sham groups. The between-group analysis of change after treatment comparing both groups also showed a significant improvement of postural stability (p = 0.03). Only in the within-group analysis several items were improved after Bonferroni correction, too, rigor 41.6% (p = 0.001), bradykinesia 23.7% (p = 0.001), tremor 30.8% (p = 0.006), and UPDRSIII sum score 23.9% (p = 0.000), but did not reach the level of significance in the between-group analysis. Conclusions. Stochastic resonance therapy significantly enhanced postural stability even in individuals with increased risk of falling. Thus it offers a potential supplementation to canonical treatments of PD. PMID:26925293

  19. Fair Water Allocation in Complex International River Systems

    NASA Astrophysics Data System (ADS)

    Beck, L.; Bernauer, T.

    2011-12-01

    Conflicts over water allocation in international freshwater systems are recurring phenomena, and climatic changes are likely to make existing problems worse in many parts of the world. Science-based proposals for water allocation frequently focus on allocating water to the economically most efficient purposes. In reality, allocation outcomes are often shaped by political and economic power, rather than considerations of economic efficiency. This paper develops a new approach to fair international water allocation in complex international freshwater systems. This approach covers both needs-based criteria - if acute water scarcity is present - and criteria for fair water allocation pertaining to relative gains in water-abundant situations. The usefulness of the approach is illustrated with a case study on the Zambezi River Basin (ZRB). Based on a hydrological model, and scenarios for water availability and demand in the ZRB until 2050, the paper shows how the waters of the ZRB could be allocated in a way that fairly distributes costs and benefits.

  20. Thermodynamics of stochastic Turing machines

    NASA Astrophysics Data System (ADS)

    Strasberg, Philipp; Cerrillo, Javier; Schaller, Gernot; Brandes, Tobias

    2015-10-01

    In analogy to Brownian computers we explicitly show how to construct stochastic models which mimic the behavior of a general-purpose computer (a Turing machine). Our models are discrete state systems obeying a Markovian master equation, which are logically reversible and have a well-defined and consistent thermodynamic interpretation. The resulting master equation, which describes a simple one-step process on an enormously large state space, allows us to thoroughly investigate the thermodynamics of computation for this situation. Especially in the stationary regime we can well approximate the master equation by a simple Fokker-Planck equation in one dimension. We then show that the entropy production rate at steady state can be made arbitrarily small, but the total (integrated) entropy production is finite and grows logarithmically with the number of computational steps.