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1

Price-based Resource Allocation in Wireless Ad Hoc Networks  

E-print Network

- associated shadow prices for wireless channel access coordination, rather than link-associated price-hop flows from an end-to-end perspective, using shadow prices as the mechanism to arbitrate channel accessPrice-based Resource Allocation in Wireless Ad Hoc Networks Yuan Xue, Baochun Li, Klara Nahrstedt

Li, Baochun

2

Stochastic quantization and holographic Wilsonian renormalization group of massless fermions in AdS  

NASA Astrophysics Data System (ADS)

We have studied holographic Wilsonian renormalization group (HWRG) of free massless fermionic fields in AdS space and its stochastic quantization (SQ) by identifying the Euclidean action with its boundary on-shell action. The natural extension of the relation between stochastic two-point correlation function and double trace coupling obtained from HWRG computation conjectured in [J.-H. Oh and D. P. Jatkar, J. High Energy Phys. 1211, 144 (2012) arXiv:1209.2242] to fermionic fields is established. We have confirmed that the stochastic two-point function precisely captures the radial flow of the double trace coupling via this relation.

Oh, Jae-Hyuk

2014-06-01

3

Optimal Resource Allocation in Wireless Ad Hoc Networks: A Price-based Approach  

E-print Network

resource allocation. In these research results, a shadow price is associated with a wi1 Optimal Resource Allocation in Wireless Ad Hoc Networks: A Price-based Approach Yuan Xue, Baochun a new price-based resource allocation framework in wireless ad hoc networks to achieve optimal resource

Nahrstedt, Klara

4

Optimal Resource Allocation in Wireless Ad Hoc Networks: A Price-based Approach  

E-print Network

resource allocation. In these research results, a shadow price is associated with a wire1 Optimal Resource Allocation in Wireless Ad Hoc Networks: A Price-based Approach Yuan Xue, Baochun a new price-based resource allocation framework in wireless ad hoc networks to achieve optimal resource

Nahrstedt, Klara

5

Optimal Resource Allocation in Wireless Ad Hoc Networks: A Price-based Approach  

E-print Network

resource allocation. In these research results, a shadow price is associated with a 1 Optimal Resource Allocation in Wireless Ad Hoc Networks: A Price-based Approach Yuan Xue, Baochun a new price-based resource allocation framework in wireless ad hoc networks to achieve optimal resource

Nahrstedt, Klara

6

Estimating technical and allocative inefficiency relative to stochastic production and cost frontiers  

Microsoft Academic Search

considered stochastic frontier production functions. This paper extends that work by considering the duality between stochastic frontier production and cost functions, under the assumptions of exact cost minimization (technical inefficiency only) and of inexact cost minimization (technical and allocative inefflciency). We show how to measure both types of inefficiency, and the associated cost of inefficiency. The techniques are illustrated using

Peter Schmidt; C. A. Knox Lovell

1979-01-01

7

Two-stage allocations for stochastic linear programming games with ...  

E-print Network

example, a group of retailers may decide to share the cost of jointly managing ... making problems; the most related here is the work on stochastic linear production games by Suijs ...... European Journal of Operational Research 179(1

2014-07-14

8

Visualization of Resource Allocation on Large-Scale Mobile Ad-hoc Networks  

E-print Network

Visualization of Resource Allocation on Large-Scale Mobile Ad-hoc Networks Alex Fridman, David interactions. 1 Introduction A mobile ad-hoc network is generally unstructured and highly dynamic, which makes on the network given the aggregate state computed at the MAC layer. We present (1) an overview of a mobile ad-hoc

9

Dynamic address allocation protocols for Mobile ad hoc networks  

E-print Network

- bility support in IPv 6 [14]. IPv 6 addresses are all 128 bits long, instead of 32 bits as in IPv4. Within this huge address space, a tiny part is reserved for all current IPv4 addresses, and another tiny part is reserved for Link-Local Addresses, which..., by participating in the Neighbour Discovery Protocol [15] and IPv 6 Stateless Address Allocation Protocol [16]. The IPv 6 Neighbor Discovery protocol can be characterized as a much improved version of two IPv4 protocols, the Address Resolution Protocol (ARP) [17...

Patchipulusu, Praveena

2012-06-07

10

Experimental evaluation of game theoretic power allocation in MIMO ad-hoc networks  

Microsoft Academic Search

Multiple input multiple output (MIMO) communication systems in an ad-hoc network can provide high spectral efficiency. Several resource allocation methods have been presented and experimentally demonstrated to improve performance in a resource limited environment. Recently, a game theoretic method has been published with promising results. The goal of this paper is to present simulation and experimental results for this game

John Kountouriotis; Kapil R. Dandekar; Nicholas J. Kirsch; Chao Liang

2009-01-01

11

Distributed on-line schedule adaptation for balanced slot allocation in wireless ad hoc networks  

E-print Network

Distributed on-line schedule adaptation for balanced slot allocation in wireless ad hoc networks, then conflict-free transmissions can take place at the same time. Even if this method mitigates collisions due period of length T. We first introduce a fluid model of the system where the conflict avoidance

12

Technical, Allocative, and Economic Efficiency in Swedish Dairy Farms: The Data Envelopment Analysis Versus the Stochastic Frontier Approach  

Microsoft Academic Search

Technical, allocative, and economic input efficiency scores were estimated for an unbalanced panel of Swedish dairy farms, using data envelopment analysis (DEA) and the stochastic frontier approach (SFA). By comparing the results it was concluded that when the entire dairy farm is studied the DEA is more appropriate to use since it does not require any particular parametric form to

Helena Johansson

2005-01-01

13

AdOpt: Analog VLSI Stochastic Optimization for Adaptive Optics Marc Cohen Mikhail Vorontsov  

E-print Network

AdOpt: Analog VLSI Stochastic Optimization for Adaptive Optics Marc Cohen Mikhail Vorontsov R). This as- sumption of a point source is the foundation of the most widely used adaptive optics control Electrical and Computer Engineering Intelligent Optics Laboratory Baltimore, MD 21218 Adelphi, MD 20783 fmarc

Cauwenberghs, Gert

14

A novel bandwidth allocation scheme for QoS routing in mobile ad hoc networks  

NASA Astrophysics Data System (ADS)

The main purpose of this paper is to propose a novel bandwidth allocation scheme for facilitating quality of service (QoS) routing in mobile ad hoc networks (MANETs). In a MANET using time division multiple access (TDMA), each node communicates with its neighbors in the same time slot. In general, finding a route with the maximum end-to-end bandwidth subject to the constraint of collision-free transmission is an NP-complete problem. This paper proposed a sub-optimal solution to this problem. The solution is based on a centrally controlled bandwidth allocation scheme to properly assign the available time slots to each intermediate link. The advantage of our proposed scheme is that the resource utilization of MANET is maximized and the end-to-end QoS is guaranteed during the route establishment period. Performance analyses show that when using the proposed scheme with AODV to perform QoS routing, it achieves about 25% throughput higher than its best-effort counterpart if the node is moving at 5mps speed.

Wu, Bin; Kuo, Geng-Sheng

2004-09-01

15

DISTRIBUTED RATE ALLOCATION FOR MULTI-STREAM VIDEO TRANSMISSION OVER AD HOC NETWORKS  

E-print Network

for the common network resources. A rate allocation algorithm must balance the available resources among bur- den can be shared. We propose a distributed rate allocation algorithm which minimizes the total of the wireless nodes, combined with the demanding rate and delay requirements of video streaming, give rise

Girod, Bernd

16

Ad Serving Using a Compact Allocation Plan PEIJI CHEN, Yahoo! Labs  

E-print Network

problem using compact allocation plans. These plans, computed offline, can be efficiently queried-second decision of choosing an appropriate guaranteed contract (demand) in such a way that in the aggregate, all

Fiat, Amos

17

Examination-Related Anxiety in Students Diagnosed with AD/HD and the Case for an Allocation of Extra Time: Perspectives of Teachers, Mothers and Students  

ERIC Educational Resources Information Center

This study details the perspectives of Western Australian teachers, students and mothers on the case for an allocation of extra exam time to students diagnosed with Attention-Deficit/Hyperactivity Disorder (AD/HD). Eighteen teachers of students with AD/HD (14 high and four primary), 15 students with AD/HD (10 high and 5 primary), and their mothers…

Taylor, Myra; Houghton, Stephen

2008-01-01

18

The Organization of Work in Social Insect Task Allocation as an Ad Hoc, Dynamical Network  

E-print Network

of colony behavior results in task allocation [1]. Colonies perform various tasks, such as foraging, care in harvester ants (Pogonomyrmex barbatus) [2]. In- side the nest, ants care for the brood (the preadult forms depend on numbers engaged in another [3,4]. Ants switch tasks, though not all transitions are possible

White, Douglas R.

19

Stochastic Traffic and Connectivity Dynamics for Vehicular Ad-Hoc Networks in Signalized Road Systems  

E-print Network

the probability distribution. When we consider vehicle arrivals as a Poisson process, the stochastic model becomes to previous PALM results in [3, 4] given that the arrival of vehicles follow a non-homogeneous Poisson process the stochastic model can approximate the probability distribution well even when vehicles interact with each

Leung, Kin K.

20

Price\\/utility-based optimized resource allocation in wireless ad hoc networks  

Microsoft Academic Search

This paper proposes a scheme for bandwidth allo- cation in wireless ad hoc networks. The Quality of Service (QoS) levels for each end-to-end flow are expressed using resource-utility functions, and our algorithms aim to maximise the aggregated utility of the flows. The scheme differentiates between applica- tions with flexible resource requirements and rigid (real-time) requirements. As an abstract notion of

Calin Curescu; Simin Nadjm-Tehrani

2005-01-01

21

IIS branch-and-cut for joint chance-constrained stochastic programs and application to optimal vaccine allocation  

Microsoft Academic Search

We present a new method for solving stochastic programs with joint chance constraints with random technology matrices and discretely distributed random data. The problem can be reformulated as a large-scale mixed 0-1 integer program. We derive a new class of optimality cuts called IIS cuts and apply them to our problem. The cuts are based on irreducibly infeasible subsystems (IIS)

Matthew W. Tanner; Lewis Ntaimo

2010-01-01

22

Networks, Buffer Allocation Problem typeset May 18, 2004 Smith & Cruz The Buffer Allocation Problem for  

E-print Network

Networks, Buffer Allocation Problem typeset May 18, 2004 Smith & Cruz The Buffer Allocation Problem for General Finite Buffer Queueing Networks J. MacGregor Smith F. R. B. Cruz e-mail: jmsmith@ecs.umass.edu e-mail: fcruz@ufmg.br May 18, 2004 Abstract -- The Buffer Allocation Problem (BAP) is a difficult stochastic

Cruz, Frederico

23

REGULAR PAPER Allocation algorithms for personal TV advertisements  

E-print Network

REGULAR PAPER Allocation algorithms for personal TV advertisements Ron Adany · Sarit Kraus personal TV advertisements to viewers. The problem's input consists of ad requests and viewers. Each ad by the deterministic version. Keywords TV advertisements Á Personalization Á Allocation Á Heuristics Á Uncertainty 1

Kraus, Sarit

24

Added Sugars  

MedlinePLUS

Added Sugars Updated:Jun 12,2014 Sugars in your diet can be naturally occurring or added. Naturally occurring sugars ... or added at the table. Foods Containing Added Sugars The major sources of added sugars are regular ...

25

Manpower Allocation and Reporting  

NASA Technical Reports Server (NTRS)

Interactive Manpower Allocation and Reporting System (MARS) helps planners make manpower allocation decisions. Includes provisions to enter overall constraints for projects and persons, assign individuals to projects, compute automatically overhead category, report on deviations from constraints, and generate manpower resource allocation reports.

Merwarth, P. D.

1983-01-01

26

Stochastic resonance  

Microsoft Academic Search

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,

Luca Gammaitoni; Peter Hänggi; Peter Jung; Fabio Marchesoni

1998-01-01

27

The allocative efficiency implications of water pollution abatement cost comparisons  

Microsoft Academic Search

Assessments of the efficiency of water pollution control allocations are usually based on abatement cost comparisons. The general rule is that efficiency is improved by reallocating abatement from sources with high marginal costs to low-cost sources. The welfare-theoretic foundation of this rule is well established for situations with nonstochastic emissions. In situations with stochastic emissions, pollution control involves improving the

James S. Shortle

1990-01-01

28

Stochastic thermodynamics  

NASA Astrophysics Data System (ADS)

'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 quest

Eichhorn, Ralf; Aurell, Erik

2014-04-01

29

Stochastic cooling  

SciTech Connect

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.

Bisognano, J.; Leemann, C.

1982-03-01

30

Ad Critic  

NSDL National Science Digital Library

Ad Critic strives to enter every television advertisement into its database of online commercials, which can be downloaded for free and viewed with QuickTime. A complete list of advertisements is indexed by company and by ad title. There are, however, also indexes of newly added ads, most-downloaded ads, movie trailers, and music found in ads, making it easier for users to search for a new or favorite advertisement. Ad Critic includes a section on advertising news and commentary and provides services for advertising agencies including online market research and detailed viewer statistics.

31

Distributed spectrum allocation via local bargaining  

Microsoft Academic Search

In this paper, we present an adaptive and dis- tributed approach to spectrum allocation in mobile ad-hoc networks. We propose a local bargaining approach where users affected by the mobility event self-organize into bargaining groups and adapt their spectrum assignment to approximate a new optimal assignment. The number of computations required to adapt to topology changes can be significantly reduced

Lili Cao; Haitao Zheng

2005-01-01

32

Online allocation algorithms with applications in computational advertising  

E-print Network

Over the last few decades, a wide variety of allocation markets emerged from the Internet and introduced interesting algorithmic challenges, e.g., ad auctions, online dating markets, matching skilled workers to jobs, etc. ...

Zadimoghaddam, Morteza

2014-01-01

33

Allocating merger savings: A flexible allocation mechanism  

SciTech Connect

Utility mergers and acquisitions are an increasingly common phenomenon. Allocating merger savings between utility ratepayers and shareholders is a sensitive issue, intimately linked to state regulatory approval, and giving rise to ratemaking issues as basic as should ratepayers be charged for premerger expenses which no longer exist. The following report presents a mechanism which can be used to allocate merger savings. The mechanism is flexible in design, does not require an explicit tracking of merger savings, and is easily calibrated to achieve any outcome with respect to (1) the overall (intended) percentage of merger savings to be received by utility ratepayers, and (2) the percentage of estimated merger savings a utility must achieve to break-even. Further, when implemented with the parameters developed below, the allocation mechanism is perfectly symmetrical; that is, potential utility upside gain is just equal to potential utility downside loss.

Polito, J.

1995-12-31

34

Drought and Water Allocation  

NSDL National Science Digital Library

The US Department of Agriculture's Water Quality Information Center at the National Agricultural Library has placed a new database online. The Drought and Water Allocation bibliography includes "71 articles on water allocation as it relates to drought and water shortages dated 1992-1999. Competition for water resources, legal rights and remedies, and economic options are highlighted."

35

Utility-Directed Allocation  

Microsoft Academic Search

This paper considers the problem of allocating discrete res ources according to utility functions reported by potential recip ients and relates this abstract problem to resource allocation in a Ut ility Data Center (UDC). A simple integer program formulation, which gen- eralizes well-known knapsack problems, permits a remarkable breadth of expression while retaining clarity and analytic tractab ility. In the

Terence Kelly

36

Channel Allocation Options.  

ERIC Educational Resources Information Center

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,…

Powers, Robert S.

37

Sensory Optimization by Stochastic Tuning  

PubMed Central

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

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

2013-01-01

38

Immigration-extinction dynamics of stochastic populations  

NASA Astrophysics Data System (ADS)

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.

Meerson, Baruch; Ovaskainen, Otso

2013-07-01

39

Google's Auction for TV Ads Preliminary version  

E-print Network

Google's Auction for TV Ads Preliminary version Noam Nisan Jason Bayer Deepak Chandra Tal Franji Robert Gardner Yossi Matias Neil Rhodes Misha Seltzer Danny Tom Hal Varian Dan Zigmond Google Inc. Abstract This document describes the auction system used by Google for allocation and pricing of TV ads

Nisan, Noam

40

Stochastic Resonance  

E-print Network

Stochastic resonance (SR) - a counter-intuitive phenomenon in which the signal due to a weak periodic force in a nonlinear system can be {\\it enhanced} by the addition of external noise - is reviewed. A theoretical approach based on linear response theory (LRT) is described. It is pointed out that, although the LRT theory of SR is by definition restricted to the small signal limit, it possesses substantial advantages in terms of simplicity, generality and predictive power. The application of LRT to overdamped motion in a bistable potential, the most commonly studied form of SR, is outlined. Two new forms of SR, predicted on the basis of LRT and subsequently observed in analogue electronic experiments, are described.

M. I. Dykman; D. G. Luchinsky; R. Mannella; P. V. E. McClintock; S. M. Soskin; N. D. Stein; N. G. Stocks

1993-07-17

41

Dynamic channel allocation by using allocation function in PCS  

Microsoft Academic Search

A dynamic channel allocation method applicable to the microcell system such as the personal communications service (PCS) is presented. The factors determining the quality of the channels are analyzed. The allocation function that consists of these factors are defined. The channel allocation for a call is processed by using the function value. While a channel is being allocated to a

Kwang Moon Cho; Samsung Plaza

1999-01-01

42

Tax Implementability of Fair Allocations  

Microsoft Academic Search

This paper examines the tax implementability of allocations based on Foley's (1967) concept of fairness as no-envy (or envy-free) and its alternatives. An allocation is tax implementable if there exists a tax schedule under which the allocation is realized as a result of agents' optimization. Tillmann (1984) and Bös and Tillmann (1985) showed that the class of fair allocations that

Yukihiro Nishimura

2000-01-01

43

The Optimal Mix of TV and Online Ads to Maximize Reach  

E-print Network

The Optimal Mix of TV and Online Ads to Maximize Reach Yuxue Jin, Georg M. Goerg, Nicolas Remy, Jim allocate budget between TV and online ads in order to maximize reach or maintain the same reach at a lower budget allocation between TV and online ads to maximize reach to the target demographics. We take

Tomkins, Andrew

44

Stochastic Analog-to-Digital Conversion Jos Luis Ceballos  

E-print Network

Stochastic Analog-to-Digital Conversion José Luis Ceballos School of Electrical Engineering a stochastic approach to data conversion. It is applicable to serial, parallel, two-step as well as delta-sigma and a comparator are combined with an accumulate-and-dump digital stage to perform serial multibit A/D conversion

Galton, Ian

45

Adding Fractions  

NSDL National Science Digital Library

In this web-based tutorial, students learn procedures for adding fractions with like and unlike denominators. The tutorial includes visual representations of the problems using pizzas, animations of the algorithm, and links to related lessons, worksheets, and practice problems.

Website, Math I.

2011-09-23

46

Multiperiod Multiproduct Advertising Budgeting. Part II: Stochastic Optimization Modeling  

E-print Network

approach. Key words: Marketing, advertising budgeting, deterministic optimization, stochastic opti in a duopolistic market where the share of each firm depends on its own and its competitors advertising decisions the effectiveness of advertising budget allocation across different themes. In [11] a Markov decisio

Beltran-Royo, Cesar

47

A Method for Reducing the Severity of Epidemics by Allocating Vaccines According to Centrality  

E-print Network

One long-standing question in epidemiological research is how best to allocate limited amounts of vaccine or similar preventative measures in order to minimize the severity of an epidemic. Much of the literature on the problem of vaccine allocation has focused on influenza epidemics and used mathematical models of epidemic spread to determine the effectiveness of proposed methods. Our work applies computational models of epidemics to the problem of geographically allocating a limited number of vaccines within several Texas counties. We developed a graph-based, stochastic model for epidemics that is based on the SEIR model, and tested vaccine allocation methods based on multiple centrality measures. This approach provides an alternative method for addressing the vaccine allocation problem, which can be combined with more conventional approaches to yield more effective epidemic suppression strategies. We found that allocation methods based on in-degree and inverse betweenness centralities tended to be the most ...

Drewniak, Krzysztof; Mikler, Armin R

2014-01-01

48

AD status and consolidation plans  

E-print Network

The CERN Antiproton Decelerator (AD) has now completed its 12th year of supplying low-energy antiproton beams for the successful physics program. Most of the machine’s key components are in operation since more than 25 years and prompted by the approval of the ELENA project, a substantial consolidation program is now being launched to ensure continued reliable operation. Over the course of the next few years a progressive renovation of the AD-Target area and the AD-ring with all the associated systems will take place. Status and performance of the AD are presented along with an overview of planned and ongoing consolidation activities with emphasis on stochastic and electron beam cooling.

Eriksson, T; Arnaudon, L; Belochitskii, P; Bojtar, L; Calviani, M; Caspers, F; Federmann, S; Jørgensen, L; Louwerse, R; Oliveira, C; Tranquille, G

2013-01-01

49

Distributed Stochastic Approximation for Adaptive Frequency Allocation in Subway Networks  

E-print Network

, Bishop's University Lennoxville, Quebec J1M 1Z7 CANADA Abstract We propose to build an intelligent day per line, while social cost is measured as the total waiting time of all passengers per day to establish the epochs of the first outgoing train every day for each line, as explained in [2] and [4

Vázquez-Abad, Felisa J.

50

Stochastic resonance  

NASA Astrophysics Data System (ADS)

We are taught by conventional wisdom that the transmission and detection of signals is hindered by noise. However, during the last two decades, the paradigm of stochastic resonance (SR) proved this assertion wrong: indeed, addition of the appropriate amount of noise can boost a signal and hence facilitate its detection in a noisy environment. Due to its simplicity and robustness, SR has been implemented by mother nature on almost every scale, thus attracting interdisciplinary interest from physicists, geologists, engineers, biologists and medical doctors, who nowadays use it as an instrument for their specific purposes. At the present time, there exist a lot of diversified models of SR. Taking into account the progress achieved in both theoretical understanding and practical application of this phenomenon, we put the focus of the present review not on discussing in depth technical details of different models and approaches but rather on presenting a general and clear physical picture of SR on a pedagogical level. Particular emphasis will be given to the implementation of SR in generic quantum systems—an issue that has received limited attention in earlier review papers on the topic. The major part of our presentation relies on the two-state model of SR (or on simple variants thereof), which is general enough to exhibit the main features of SR and, in fact, covers many (if not most) of the examples of SR published so far. In order to highlight the diversity of the two-state model, we shall discuss several examples from such different fields as condensed matter, nonlinear and quantum optics and biophysics. Finally, we also discuss some situations that go beyond the generic SR scenario but are still characterized by a constructive role of noise.

Wellens, Thomas; Shatokhin, Vyacheslav; Buchleitner, Andreas

2004-01-01

51

Stochastic Optimization Modeling  

E-print Network

study, the expected profit of the stochastic approach has been favorably compared with the ex- ..... An experimental case is analyzed for showing the improvement that the ..... Competitive advertising under uncertainty: A stochastic differential.

2014-07-04

52

Resource Allocation in Fading Ad-Hoc Networks  

E-print Network

(t)Pi(t)Fii(t) Interferences from Lj's (i = j): Gij(t)Pj(t)Fij(t) Instantaneous SIR: SIRi(t) = Gii(t)Pi(t)Fii(t) j=i Gij.r.t. interferences Fij has unit mean Fij independent from Fi j fading slow w.r.t. symbol rate Avg. SIRi = E SIRi,s University of California, Irvine ­ p.8/16 #12;3-State Markov-Chain State 1 State 2 State 3 p12 p

Yousefi'zadeh, Homayoun

53

Register allocation instruction  

E-print Network

the program; just means more registers may be needed. Assuming a variable is dead when it is really live loads and stores ¯ optimal allocation is difficult µ NP-complete for k 1 registers 1 #12;Liveness of registers Approach: ¯ temporaries with disjoint live ranges can map to same register ¯ if not enough

Zhang, Xiangyu

54

Frequency (Stochastic) Resonance and Stochastic Resonance for a Superconducting Junctions' Device  

NASA Astrophysics Data System (ADS)

In this paper, we investigate a Josephson-junction device with dichotomous resistance or a special SQUID (superconducting quantum interference device). It is shown that frequency (stochastic) resonance and stochastic resonance can appear for some suitably selected parameters' values of the device respectively. Our results can provide some insights for the investigation of the SQUID response to the signal (including the input alternating current, the added alternating voltage, the vertically added alternating magnetic field, and the detected (electric-magnetic) temporal-periodic signal).

Li, Jing-Hui

2014-06-01

55

Stochastic amplification in epidemics  

E-print Network

REPORT Stochastic amplification in epidemics David Alonso1, *, Alan J. McKane2 and Mercedes Pascual, we present a stochastic theory for the major dynamical transitions in epidemics from regular in nonlinear ecological systems in general. Keywords: epidemics; oscillations; stochastic modelling; childhood

McKane, Alan

56

Mechanical Stochastic Resonance  

NASA Astrophysics Data System (ADS)

Noise and nonlinearity can produce a stochastic resonance that maximizes a system's output signal-to-noise ratio. Stochastic resonance has been observed in electronic, chemical, optical, magnetic, and biological systems. Here, we report stochastic resonance in a simple mechanical system consisting of a bistable pendulum driven by a harmonic oscillator and the broad-band noise of a flapping flag.

Wainwright, Elliot; Lindner, John

2013-03-01

57

Spectrum allocations above 40 GHz  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

58

Aid allocation and poverty reduction  

Microsoft Academic Search

This paper derives a poverty-efficient allocation of aid and compares it with actual aid allocations. The allocation of aid that has the maximum effect on poverty depends on the level of poverty and the quality of policies. Using the headcount, poverty-gap, and squared poverty gap measures of poverty, alternatively, all yield similar poverty-efficient allocations. Finally, we find that the actual

Paul Collier; David Dollar

2002-01-01

59

Synaptic Tagging During Memory Allocation  

PubMed Central

There is now compelling evidence that the allocation of memory to specific neurons (neuronal allocation) and synapses (synaptic allocation) in a neurocircuit is not random and that instead specific mechanisms, such as increases in neuronal excitability and synaptic tagging and capture, determine the exact sites where memories are stored. We propose an integrated view of these processes, such that neuronal allocation, synaptic tagging and capture, spine clustering and metaplasticity reflect related aspects of memory allocation mechanisms. Importantly, the properties of these mechanisms suggest a set of rules that profoundly affect how memories are stored and recalled. PMID:24496410

Rogerson, Thomas; Cai, Denise; Frank, Adam; Sano, Yoshitake; Shobe, Justin; Aranda, Manuel L.; Silva, Alcino J.

2014-01-01

60

Optimal Allocation of Reactive Power Source in Wind Farms Using Sensitivity Analysis and Tabu Algorithm  

Microsoft Academic Search

Considering wind farms real operation characteristics, a novel method using sensitivity analysis and Tabu algorithm for reactive power compensation allocations is proposed. In this paper, the sensitivity coefficient is defined as partial derivative of voltage\\/reactive power. The nodes that have higher sensitivity coefficient are selected for install capacitors or SVC to reduce the voltage to the largest extent. The stochastic

Zhang Ping; Zeng Xiang Jun; Li Ling

2008-01-01

61

Distributed Processor Allocation For Discrete Event Simulation and Digital Signal Processing Using a Multiobjective Evolutionary Algorithm  

E-print Network

Engineering Graduate School of Engineering and Management Air Force Institute of Technology Wright Patterson. A stochastic processor allocation algorithm is developed for assigning processes to processors in an effective simultaneously across the processors. The efficiency and effectiveness of the distributed system is dependent

Coello, Carlos A. Coello

62

Stochastic counterfactuals and stochastic sufficient causes  

PubMed Central

Most work in causal inference concerns deterministic counterfactuals; the literature on stochastic counterfactuals is small. In the stochastic counterfactual setting, the outcome for each individual under each possible set of exposures follows a probability distribution so that for any given exposure combination, outcomes vary not only between individuals but also probabilistically for each particular individual. The deterministic sufficient cause framework supplements the deterministic counterfactual framework by allowing for the representation of counterfactual outcomes in terms of sufficient causes or causal mechanisms. In the deterministic sufficient cause framework it is possible to test for the joint presence of two causes in the same causal mechanism, referred to as a sufficient cause interaction. In this paper, these ideas are extended to the setting of stochastic counterfactuals and stochastic sufficient causes. Formal definitions are given for a stochastic sufficient cause framework. It is shown that the empirical conditions that suffice to conclude the presence of a sufficient cause interaction in the deterministic sufficient cause framework suffice also to conclude the presence of a sufficient cause interaction in the stochastic sufficient cause framework. Two examples from the genetics literature, in which there is evidence that sufficient cause interactions are present, are discussed in light of the results in this paper.

VANDERWEELE, TYLER J.; ROBINS, JAMES M.

2014-01-01

63

The appreciation of stochastic motion in particle accelerators  

SciTech Connect

A description is given of the analytic and numerical work, performed from July 1955 through August 1956, so as to develop, and then study, the process of making intense proton beams, suitable for colliding beams. It is shown how this investigation led, in a most natural way, to the realization that stochasticity can arise in a simple Hamiltonian system. Furthermore, the criterion for the onset of stochasticity was understood, and carefully studied, in two different situations. The first situation was the proposed (and subsequently used) ''stacking process'' for developing an intense beam, where stochasticity occurs as additional particles are added to the intense circulating beam. The second situation occurs when one seeks to develop ''stochastic accelerators'' in which particles are accelerated (continuously) by a collection of radio frequency systems. It was in the last connection that the well-known criterion for stochasticity, resonance overlap, was obtained.

Symon, Keith; Sessler, Andrew

2003-08-03

64

Stochastic volatility models and Kelvin waves  

NASA Astrophysics Data System (ADS)

We use stochastic volatility models to describe the evolution of an asset price, its instantaneous volatility and its realized volatility. In particular, we concentrate on the Stein and Stein model (SSM) (1991) for the stochastic asset volatility and the Heston model (HM) (1993) for the stochastic asset variance. By construction, the volatility is not sign definite in SSM and is non-negative in HM. It is well known that both models produce closed-form expressions for the prices of vanilla option via the Lewis-Lipton formula. However, the numerical pricing of exotic options by means of the finite difference and Monte Carlo methods is much more complex for HM than for SSM. Until now, this complexity was considered to be an acceptable price to pay for ensuring that the asset volatility is non-negative. We argue that having negative stochastic volatility is a psychological rather than financial or mathematical problem, and advocate using SSM rather than HM in most applications. We extend SSM by adding volatility jumps and obtain a closed-form expression for the density of the asset price and its realized volatility. We also show that the current method of choice for solving pricing problems with stochastic volatility (via the affine ansatz for the Fourier-transformed density function) can be traced back to the Kelvin method designed in the 19th century for studying wave motion problems arising in fluid dynamics.

Lipton, Alex; Sepp, Artur

2008-08-01

65

Factor stochastic volatility with time varying loadings and Markov switching regimes  

Microsoft Academic Search

We generalize the factor stochastic volatility (FSV) model of Pitt and Shephard [1999. Time varying covariances: a factor stochastic volatility approach (with discussion). In: Bernardo, J.M., Berger, J.O., Dawid, A.P., Smith, A.F.M. (Eds.), Bayesian Statistics, vol. 6, Oxford University Press, London, pp. 547–570.] and Aguilar and West [2000. Bayesian dynamic factor models and variance matrix discounting for portfolio allocation. J.

Hedibert Freitas Lopes; Carlos Marinho Carvalho

2007-01-01

66

3739SPACE ALLOCATION/RE-ALLOCATION PROCEDURE Client identifies  

E-print Network

Page 1 3739SPACE ALLOCATION/RE-ALLOCATION PROCEDURE Client identifies space requirement Client completes space request form Submit space request form to Space Management Office Space Management Office acknowledge receipt Is space form completed accurately Is there vacant space Space Management Office conduct

67

Google's Auction for Radio and TV Ads Preliminary version  

E-print Network

Google's Auction for Radio and TV Ads Preliminary version Noam Nisan Jason Bayer Deepak Chandra Tal Franji Robert Gardner Yossi Matias Neil Rhodes Misha Seltzer Danny Tom Hal Varian Dan Zigmond Google Inc. Abstract This document describes the auction system used by Google for allocation and pricing of TV ads

Tomkins, Andrew

68

Stochastic Processes for Physicists  

NASA Astrophysics Data System (ADS)

1. A review of probability theory; 2. Differential equations; 3. Stochastic equations with Gaussian noise; 4. Further properties of stochastic processes; 5. Some applications of Gaussian noise; 6. Numerical methods for Gaussian noise; 7. Fokker-Planck equations and reaction-diffusion systems; 8. Jump processes; 9. Levy processes; 10. Modern probability theory; Appendix; References; Index.

Jacobs, Kurt

2010-02-01

69

Adaptive channel allocation in TACS  

Microsoft Academic Search

The paper describes an adaptive channel allocation, ACA, algorithm designed for an analog cellular system like TACS. The incentive to use more advanced radio resource allocation algorithms can be to eliminate frequency planning, to increase the capacity and improve the quality of the system. Specific to TACS is that measurements only are available in the uplink. Based on these limited

M. Almgren; M. Frodigh; B. Hansson; J. Lundequist; K. Wallstedt

1995-01-01

70

Aid Allocation and Aid Effectiveness  

Microsoft Academic Search

The paper performs aid allocation analysis using OECD-DAC data covering 20 aid donors and 176 recipients over the period 1980-2003. We improve upon earlier work in this area by employing inter alia the variable 'past outcome' measuring aid effectiveness in order to link together aid allocation and aid effectiveness. In line with previous work, we also account for both altruistic

Alessia Isopi; George Mavrotas

2006-01-01

71

Stability of AdS black strings  

E-print Network

We review the recent developements in the stability problem and phase diagram for asymptotically locally $AdS$ black strings. First, we quickly review the case of locally flat black string before turning to the case of locally $AdS$ spacetimes.

T. Delsate

2008-08-14

72

49 CFR 262.5 - Allocation requirements.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Allocation requirements. 262...IMPLEMENTATION OF PROGRAM FOR CAPITAL GRANTS FOR RAIL LINE RELOCATION AND IMPROVEMENT...PROJECTS § 262.5 Allocation requirements...excluded from this allocation formula. FRA...

2010-10-01

73

15 CFR 923.110 - Allocation formula.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Allocation formula. 923.110 Section...COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT COASTAL ZONE MANAGEMENT PROGRAM REGULATIONS Allocation of Section 306 Program Administration Grants § 923.110 Allocation formula. (a)...

2010-01-01

74

Quantum Stochastic Generators  

E-print Network

We discuss stochastic derivations, stochastic Hamiltonians and the flows that they generate, algebraic fluctuaion-dissipation theorems, etc., in a language common to both classical and quantum algebras. It is convenient to define distinct notions of time-ordered exponentials to take account of the breakdown of the Leibniz rule in the Ito calculus. We introduce a notion of quantum Stratonovich calculus and show how it relates to Stratonovich-Dyson time ordered exponentials. We then use it to demonstrate a natural way to add stochastic derivations.

John Gough

2003-09-12

75

Resource allocation using risk analysis  

SciTech Connect

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.

Bott, T. F. (Terrence F.); Eisenhawer, S. W. (Stephen W.)

2003-01-01

76

Multivariate Stochastic Volatility  

Microsoft Academic Search

We provide a detailed summary of the large and vibrant emerging literature that deals with the multivariate modeling of conditional\\u000a volatility of financial time series within the framework of stochastic volatility. The developments and achievements in this\\u000a area represent one of the great success stories of financial econometrics. Three broad classes of multivariate stochastic\\u000a volatility models have emerged: one that

Siddhartha Chib; Yasuhiro Omori; Manabu Asai

2007-01-01

77

Stochastic Models of Evolution  

NASA Astrophysics Data System (ADS)

To continue the discussion of randomness given in Sect. 2.2.1, we briefly touch on stochastic models of temporal evolution (random processes). They can be specified either via explicit definition of their statistical properties (probability density functions, correlation functions, etc., Sects. 4.1, 4.2 and 4.3) or via stochastic difference or differential equations. Some of the most widely known equations, their properties and applications are discussed in Sects. 4.4 and 4.5.

Bezruchko, Boris P.; Smirnov, Dmitry A.

78

Positive stochastic volatility simulation  

Microsoft Academic Search

Abstract We present a positivity preserving numerical scheme for the pathwise solu- tion of nonlinear stochastic differential equations driven by a multi-dimensional Wiener process and governed by non-commutative linear and non-Lipschitz vector fields. This strong order one scheme uses: (i) Strang exponential splitting, an approximation that decomposes the stochastic flow separately into the drift flow, and the pure diffusion flow

Anke Wiese

79

Differential evolution method for stochastic flow shop scheduling with limited buffers  

Microsoft Academic Search

The flow shop scheduling problem (FSSP) with limited buffers constraint is a typical NP-hard combinatorial optimization problem and represents an important area in production scheduling. In this paper, a class of differential evolution (DE) method with the optimal computing budget allocation (OCBA) technique and hypothesis test (HT), namely OHTDE, is proposed for the stochastic flow shop scheduling with limited buffers

Rong Hu; Ling Wang; Bin Qian; Fu-zhuo Huang

2008-01-01

80

Inexact fuzzy-stochastic quadratic programming approach for waste management under multiple uncertainties  

Microsoft Academic Search

In this study, an inexact fuzzy-stochastic quadratic programming (IFSQP) method is developed for effectively allocating waste to available facilities. The IFSQP approach is an extension of the conventional inexact linear programming for handling nonlinear programming in the objective function and multiple uncertainties on parameters in the constraints. The developed IFSQP is applied to a municipal solid waste management system. The

P. Guo; G. H. Huang

2011-01-01

81

Bayesian Proportional Resource Allocation Games  

E-print Network

We consider a proportional allocation mechanism that gives to each user an amount of a resource proportional to the user's bid. We study a corresponding Bayesian game in which each user has incomplete information on the ...

Tsitsiklis, John N.

82

Resource allocation planning helper (RALPH)  

NASA Technical Reports Server (NTRS)

The following topics are presented in view graph form: the background of the Resource Allocation Planning Helper (RALPH); RALPH schedule lifecycle; scheduling approach; technology layering; details; and RALPH directions.

Werntz, David G.

1991-01-01

83

Collective credit allocation in science  

E-print Network

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, since 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...

Shen, Hua-Wei

2014-01-01

84

Collaborative Resource Allocation  

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

85

Determining the Appropriate Asset Allocation  

E-print Network

THE APPROPRIATE ASSET ALLOCATION Jason Johnson and Wade Polk* * Assistant Professor and Extension Economist?Management and Extension Program Specialist?Risk Management, The Texas A&M University System Liquidity Liquidity refers to the ease with which an investment... THE APPROPRIATE ASSET ALLOCATION Jason Johnson and Wade Polk* * Assistant Professor and Extension Economist?Management and Extension Program Specialist?Risk Management, The Texas A&M University System Liquidity Liquidity refers to the ease with which an investment...

Johnson, Jason; Polk, Wade

2002-08-12

86

Inverse Statistics and Asset Allocation Efficiency  

NASA Astrophysics Data System (ADS)

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.

Bolgorian, Meysam

87

Subpopulation triage: how to allocate conservation effort among populations.  

PubMed

Threatened species often exist in a small number of isolated subpopulations. Given limitations on conservation spending, managers must choose from strategies that range from managing just one subpopulation and risking all other subpopulations to managing all subpopulations equally and poorly, thereby risking the loss of all subpopulations. We took an economic approach to this problem in an effort to discover a simple rule of thumb for optimally allocating conservation effort among subpopulations. This rule was derived by maximizing the expected number of extant subpopulations remaining given n subpopulations are actually managed. We also derived a spatiotemporally optimized strategy through stochastic dynamic programming. The rule of thumb suggested that more subpopulations should be managed if the budget increases or if the cost of reducing local extinction probabilities decreases. The rule performed well against the exact optimal strategy that was the result of the stochastic dynamic program and much better than other simple strategies (e.g., always manage one extant subpopulation or half of the remaining subpopulation). We applied our approach to the allocation of funds in 2 contrasting case studies: reduction of poaching of Sumatran tigers (Panthera tigris sumatrae) and habitat acquisition for San Joaquin kit foxes (Vulpes macrotis mutica). For our estimated annual budget for Sumatran tiger management, the mean time to extinction was about 32 years. For our estimated annual management budget for kit foxes in the San Joaquin Valley, the mean time to extinction was approximately 24 years. Our framework allows managers to deal with the important question of how to allocate scarce conservation resources among subpopulations of any threatened species. PMID:18477029

McDonald-Madden, Eve; Baxter, Peter W J; Possingham, Hugh P

2008-06-01

88

STOCHASTIC STABILITY OF A CLASS OF STOCHASTIC BILINEAR HYBRID SYSTEMS  

E-print Network

stochastic stability - Positive invariance - LMI. 1. INTRODUCTION Active fault tolerant control systems stochastic sta- bilization of continuous time Bilinear Active Fault Tolerant Control Systems with Markovian: Active Fault Tolerant Control - Bilinear systems - Hybrid systems - Markovian jumping parameters - Local

Boyer, Edmond

89

STOCHASTIC COOLING FOR BUNCHED BEAMS.  

SciTech Connect

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.

BLASKIEWICZ, M.

2005-05-16

90

Stochastic resonance of quantum discord  

E-print Network

We study the stochastic resonance of quantum discord (“discord resonance”) in coupled quantum systems and make a comparison with the stochastic resonance of entanglement (“entanglement resonance”). It is found that the ...

Lee, Chee Kong

91

BPS Geometries and AdS Bubbles  

E-print Network

Recently, 1/2-BPS AdS bubble solutions have been obtained by Lin, Lunin and Maldacena, which correspond to Fermi droplets in phase space in the dual CFT picture. They can be thought of as generalisations of 1/2-BPS AdS black hole solutions in five or seven dimensional gauged supergravity. In this paper, we extend these solutions by invoking additional gauge fields and scalar fields in the supergravity Lagrangians, thereby obtaining AdS bubble generalisations of the previously-known multi-charge AdS black solutions of gauged supergravity. We also obtain analogous AdS bubble solutions in four-dimensional gauged supergravity. Our solutions generically preserve supersymmetry fractions 1/4, 1/8 and 1/8 in seven, five and four dimensions respectively. They can be lifted to M-theory or type IIB string theory, using previously known formulae for the consistent Pauli sphere reductions that yield the gauged supergravities. We also find similar solutions in six-dimensional gauged supergravity, and discuss their lift to the massive type IIA theory.

Z. -W. Chong; H. Lu; C. N. Pope

2004-12-20

92

Hamiltonian mechanics of stochastic acceleration.  

PubMed

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

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

2013-11-01

93

Stochastic homogenization and random lattices  

Microsoft Academic Search

We present some variants of stochastic homogenization theory for scalar elliptic equations of the form ?div[A(x?,?)?u(x,?)]=f. These variants basically consist in defining stochastic coefficients A(x?,?) from stochastic deformations (using random diffeomorphisms) of the periodic setting, as announced in [X. Blanc, C. Le Bris, P.-L. Lions, Une variante de la théorie de l'homogénéisation stochastique des opérateurs elliptiques (A variant of stochastic

X. Blanc; C. Le Bris; P.-L. Lions

2007-01-01

94

Stochastic Feedforward Control Technique  

NASA Technical Reports Server (NTRS)

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.

Halyo, Nesim

1990-01-01

95

Stochastic modeling of rainfall  

SciTech Connect

We review several approaches in the literature for stochastic modeling of rainfall, and discuss some of their advantages and disadvantages. While stochastic precipitation models have been around at least since the 1850`s, the last two decades have seen an increased development of models based (more or less) on the physical processes involved in precipitation. There are interesting questions of scale and measurement that pertain to these modeling efforts. Recent modeling efforts aim at including meteorological variables, and may be useful for regional down-scaling of general circulation models.

Guttorp, P. [Univ. of Washington, Seattle, WA (United States)

1996-12-31

96

Capital allocation, stock return volatility and productivity growth in US industries  

Microsoft Academic Search

Using firm-level Compustat data from 1971 to 2000, we report a substantial cross-industry variation of allocative efficiency in capital expenditure in the US economy. Industries with higher allocative efficiency are the ones with higher firm-level value-added growth heterogeneity, higher information transparency captured by firm-specific stock return volatility and faster long-run productivity growth. This finding is consistent with the idea of

Hyunbae Chun; Jung-Wook Kim

2011-01-01

97

Constructing Lifshitz solutions from AdS  

NASA Astrophysics Data System (ADS)

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.

Cassani, Davide; Faedo, Anton F.

2011-05-01

98

Task allocation among multiple intelligent robots  

NASA Technical Reports Server (NTRS)

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.

Gasser, L.; Bekey, G.

1987-01-01

99

On Stochastic Approximation.  

ERIC Educational Resources Information Center

This paper deals with a stochastic process for the approximation of the root of a regression equation. This process was first suggested by Robbins and Monro. The main result here is a necessary and sufficient condition on the iteration coefficients for convergence of the process (convergence with probability one and convergence in the quadratic…

Wolff, Hans

100

Multistage quadratic stochastic programming  

NASA Astrophysics Data System (ADS)

Quadratic stochastic programming (QSP) in which each subproblem is a convex piecewise quadratic program with stochastic data, is a natural extension of stochastic linear programming. This allows the use of quadratic or piecewise quadratic objective functions which are essential for controlling risk in financial and project planning. Two-stage QSP is a special case of extended linear-quadratic programming (ELQP). The recourse functions in QSP are piecewise quadratic convex and Lipschitz continuous. Moreover, they have Lipschitz gradients if each QP subproblem is strictly convex and differentiable. Using these properties, a generalized Newton algorithm exhibiting global and superlinear convergence has been proposed recently for the two stage case. We extend the generalized Newton algorithm to multistage QSP and show that it is globally and finitely convergent under suitable conditions. We present numerical results on randomly generated data and modified publicly available stochastic linear programming test sets. Efficiency schemes on different scenario tree structures are discussed. The large-scale deterministic equivalent of the multistage QSP is also generated and their accuracy compared.

Lau, Karen K.; Womersley, Robert S.

2001-04-01

101

On stochastic bilinear control  

Microsoft Academic Search

The object is to provide a condensed review of current research on bilinear stochastic systems, BLSS and their application, along with preliminary results on optimal filtering. BLSS arise naturally for generalized demographic processes such as may appear in immunology, nuclear physics, biological populations of species and human demography. For example, in the immune system bilinear differential equations describe cell division

R. R. Mohler; W. J. Kolodziej

1979-01-01

102

The stochastic Burgers Equation  

Microsoft Academic Search

We study Burgers Equation perturbed by a white noise in space and time. We prove the existence of solutions by showing that the Cole-Hopf transformation is meaningful also in the stochastic case. The problem is thus reduced to the anaylsis of a linear equation with multiplicativehalf white noise. An explicit solution of the latter is constructed through a generalized Feynman-Kac

L. Bertini; N. Cancrini; G. Jona-Lasinio

1994-01-01

103

PROBABILITY AND STOCHASTIC PROCESSES  

E-print Network

107 or 108 of the 1976 United States Copyright Act, without either the prior written permission Probability and Stochastic Processes to Rutgers undergraduates in 1991, we never dreamed we would write, in itself, of minor interest. What the students want most is an intuitive grasp of the basic concepts

Kozick, Richard J.

104

INSTRUCTIONAL CONFERENCE ON THE THEORY OF STOCHASTIC PROCESSES: Operator stochastic differential equations and stochastic semigroups  

NASA Astrophysics Data System (ADS)

CONTENTSIntroduction § 1. The finite-dimensional case § 2. Stochastic semigroups in the L2-strong theory § 3. Homogeneous strongly continuous semigroups with the group of the first moments § 4. Stochastic equations of diffusion type with constant coefficients § 5. Continuous homogeneous stochastic semigroups in the presence of two moments References

Skorokhod, A. V.

1982-12-01

105

The message delay in mobile ad hoc networks  

Microsoft Academic Search

A stochastic model is introduced that accurately models the message delay in mo- bile ad hoc networks where nodes relay messages and the networks are sparsely populated. The model has only two input parameters: the number of nodes and the parameter of an exponential distribution which describes the time until two random mobiles come within communication range of one another.

Robin Groenevelt; Philippe Nain; Ger Koole

2005-01-01

106

Stochastic computing with biomolecular automata  

NASA Astrophysics Data System (ADS)

Stochastic computing has a broad range of applications, yet electronic computers realize its basic step, stochastic choice between alternative computation paths, in a cumbersome way. Biomolecular computers use a different computational paradigm and hence afford novel designs. We constructed a stochastic molecular automaton in which stochastic choice is realized by means of competition between alternative biochemical pathways, and choice probabilities are programmed by the relative molar concentrations of the software molecules coding for the alternatives. Programmable and autonomous stochastic molecular automata have been shown to perform direct analysis of disease-related molecular indicators in vitro and may have the potential to provide in situ medical diagnosis and cure.

Adar, Rivka; Benenson, Yaakov; Linshiz, Gregory; Rosner, Amit; Tishby, Naftali; Shapiro, Ehud

2004-07-01

107

AdBlockVideo  

NSDL National Science Digital Library

Video ads can be quite a nuisance. AdBlockVideo can help users out by effectively blocking such ads. Visitors will need to download the program and they can toggle AdBlockVideo on and off as they see fit. This application is compatible with computers running Windows 98 and newer, Max OS 10.3 and newer, and Linux.

2011-01-01

108

AdS braneworld with backreaction  

NASA Astrophysics Data System (ADS)

We review the tachyon model derived from the dynamics of a 3-brane moving in the AdS5 bulk. The bulk geometry is based on the Randall-Sundrum II model extended to include the radion. The effective tachyon Lagrangian is modified due to the back-reaction of the brane on the bulk geometry.

Bili?, Neven; Tupper, Gary B.

2014-03-01

109

Scalar collapse in AdS spacetimes  

NASA Astrophysics Data System (ADS)

Recently, studies of the gravitational collapse of a scalar field within spherically symmetric anti-de Sitter (AdS) spacetimes presented by Bizon and Rostroworoski [Phys. Rev. Lett. 107, 031102 (2011)], Jalmuzna et al. [Phys. Rev. D 84, 085021 (2011).] showed an instability of pure AdS to black hole formation. In particular, the work showed that arbitrarily small initial configurations of a scalar field evolved through some number of reflections off the AdS boundary until a black hole forms. We consider this same system, extended to include a complex scalar field, and reproduce this phenomena. We present tests of our numerical code that demonstrate convergence and consistency. We study the properties of the evolution as the scalar pulse becomes more compact by examining the asymptotic behavior of the scalar field, an observable in the corresponding boundary conformal field theory. We demonstrate that such black hole formation occurs even when one places a reflecting boundary at finite radius, indicating that the sharpening is a property of gravity in a bounded domain and not of AdS itself. We examine how the initial energy is transferred to higher frequencies—which leads to black hole formation—and uncover interesting features of this transfer.

Buchel, Alex; Lehner, Luis; Liebling, Steven L.

2012-12-01

110

AdS orbifolds and Penrose limits  

SciTech Connect

In this paper we study the Penrose limit of AdS{sub 5} orbifolds. The orbifold can be either in the pure spatial directions or space and time directions. For the AdS{sub 5}/{Lambda} x S{sup 5} spatial orbifold we observe that after the Penrose limit we obtain the same result as the Penrose limit of AdS{sub 5} x S{sup 5}/{Lambda}. We identify the corresponding BMN operators in terms of operators of the gauge theory on R x S{sup 3}/{Lambda}. The semi-classical description of rotating strings in these backgrounds have also been studied. For the spatial AdS orbifold we show that in the quadratic order the obtained action for the fluctuations is the same as that in S{sup 5} orbifold, however, the higher loop correction can distinguish between two cases.

Alishahiha, Mohsen; Sheikh-Jabbari, Mohammad M.; Tatar, Radu

2002-12-09

111

AdS duals of matrix strings  

NASA Astrophysics Data System (ADS)

We review recent work on the holographic duals of type II and heterotic matrix string theories described by warped AdS3 supergravities. In particular, we compute the spectra of Kaluza-Klein primaries for type I, II supergravities on warped AdS3 × S7 and match them with the primary operators in the dual two-dimensional gauge theories. The presence of non-trivial warp factors and dilaton profiles requires a modification of the familiar dictionary between masses and 'scaling' dimensions of fields and operators. We present these modifications for the general case of domain wall/QFT correspondences between supergravities on warped AdSd+1 × Sq geometries and super Yang-Mills theories with 16 supercharges.

Morales, Jose F.; Samtleben, Henning

2003-06-01

112

Dynamic versus static allocation policies in multipurpose multireservoir systems  

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

113

Resource Allocation in Streaming Environments  

Microsoft Academic Search

This paper considers resource allocation algorithms for processing streams of events on computational grids. For example, financial trading applications are executed on large computational grids that receive streams of data such as stock ticker prices, commodity prices, foreign-exchange rates and total risk exposure. The economic value of a com- putation depends on the time taken to execute it; an arbi-

Lu Tian; K. Mani Chandy

2006-01-01

114

Operational risk economic capital allocation  

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

115

Resource Allocation: A Participatory Process.  

ERIC Educational Resources Information Center

Whether a participatory process for resource allocation in a public community college setting occurs depends upon several key factors: (1) the leadership style of the institutional chief executive officer; (2) the administrative organizational structure of the institution; (3) the relationship which exists between and among members of the various…

Reid, Alban E.

116

Reconfigurable antennas for MIMO ad-hoc networks  

Microsoft Academic Search

In this paper we investigate the performance of reconflgurable antennas in an MIMO ad-hoc network. The nodes employ the multiuser waterfllling (known also as iterative waterfllling) power allocation [1], [2] method and we use network sum capacity as a performance metric. We study a centralized configuration selection scheme, which can be used as an upper bound in the sum capacity

John Kountouriotis; Daniele Piazza; Prathaban Mookiah; Michele D'Amico; Kapil R. Dandekar

2008-01-01

117

Stochastic extensions of the regularized Schrödinger-Newton equation  

E-print Network

We show that the Schr\\"odinger-Newton equation, which describes the nonlinear time evolution of self-gravitating quantum matter, can be made compatible with the no-signaling requirement by elevating it to a stochastic differential equation. In the deterministic form of the equation, as studied so far, the nonlinearity would lead to diverging energy corrections for localized wave packets and would create observable correlations admitting faster-than-light communication. By regularizing the divergencies and adding specific random jumps or a specific Brownian noise process, the effect of the nonlinearity vanishes in the stochastic average and gives rise to a linear and Galilean invariant evolution of the density operator.

Stefan Nimmrichter; Klaus Hornberger

2014-10-17

118

Phase transitions in crowd dynamics of resource allocation.  

PubMed

We define and study a class of resource allocation processes where gN agents, by repeatedly visiting N resources, try to converge to an optimal configuration where each resource is occupied by at most one agent. The process exhibits a phase transition, as the density g of agents grows, from an absorbing to an active phase. In the latter, even if the number of resources is in principle enough for all agents (g<1), the system never settles to a frozen configuration. We recast these processes in terms of zero-range interacting particles, studying analytically the mean field dynamics and investigating numerically the phase transition in finite dimensions. We find a good agreement with the critical exponents of the stochastic fixed-energy sandpile. The lack of coordination in the active phase also leads to a nontrivial faster-is-slower effect. PMID:22463162

Ghosh, Asim; De Martino, Daniele; Chatterjee, Arnab; Marsili, Matteo; Chakrabarti, Bikas K

2012-02-01

119

Dynamic Resource Allocation in Disaster Response: Tradeoffs in Wildfire Suppression  

PubMed Central

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

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

2012-01-01

120

Stochasticity and evolutionary stability  

NASA Astrophysics Data System (ADS)

In stochastic dynamical systems, different concepts of stability can be obtained in different limits. A particularly interesting example is evolutionary game theory, which is traditionally based on infinite populations, where strict Nash equilibria correspond to stable fixed points that are always evolutionarily stable. However, in finite populations stochastic effects can drive the system away from strict Nash equilibria, which gives rise to a new concept for evolutionary stability. The conventional and the new stability concepts may apparently contradict each other leading to conflicting predictions in large yet finite populations. We show that the two concepts can be derived from the frequency dependent Moran process in different limits. Our results help to determine the appropriate stability concept in large finite populations. The general validity of our findings is demonstrated showing that the same results are valid employing vastly different co-evolutionary processes.

Traulsen, Arne; Pacheco, Jorge M.; Imhof, Lorens A.

2006-08-01

121

Entropy of stochastic flows  

SciTech Connect

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.

Dorogovtsev, Andrei A [Institute of Mathematics of Ukrainian National Academy of Sciences, Kiev (Ukraine)

2010-06-29

122

Stochastic resonance without tuning  

Microsoft Academic Search

STOCHASTIC resonance1á¤-4 (SR) is a phenomenon wherein the response of a nonlinear system to a weak periodic input signal is optimized by the presence of a particular, non-zero level of noise5 á¤-7. SR has been proposed as a means for improving signal detection in a wide variety of systems, including superconducting quantum interference devices8, and may be used in some

J. J. Collins; Carson C. Chow; Thomas T. Imhoff

1995-01-01

123

Performance Investigation of Virtual Private Networks with Different Bandwidth Allocations  

E-print Network

A Virtual Private Network (VPN) provides private network connections over a publicly accessible shared network. The effective allocation of bandwidth for VPNs assumes significance in the present scenario due to varied traffic. Each VPN endpoint specifies bounds on the total amount of traffic that it is likely to send or receive at any time. The network provider tailors the VPN so that there is sufficient bandwidth for any traffic matrix that is consistent with these bounds. The approach incorporates the use of Ad-hoc On demand Distance Vector (AODV) protocol, with a view to accomplish an enhancement in the performance of the mobile networks. The NS2 based simulation results are evaluated in terms of its metrics for different bandwidth allocations, besides analyzing its performance in the event of exigencies such as link failures. The results highlight the suitability of the proposed strategy in the context of real time applications.

Natarajan, Mahalakshmi Chidambara; Nachiappan, Alamelu

2010-01-01

124

SHALE: An Efficient Algorithm for Allocation of Guaranteed Display Advertising  

E-print Network

Motivated by the problem of optimizing allocation in guaranteed display advertising, we develop an efficient, lightweight method of generating a compact {\\em allocation plan} that can be used to guide ad server decisions. The plan itself uses just O(1) state per guaranteed contract, is robust to noise, and allows us to serve (provably) nearly optimally. The optimization method we develop is scalable, with a small in-memory footprint, and working in linear time per iteration. It is also "stop-anytime", meaning that time-critical applications can stop early and still get a good serving solution. Thus, it is particularly useful for optimizing the large problems arising in the context of display advertising. We demonstrate the effectiveness of our algorithm using actual Yahoo! data.

Bharadwaj, Vijay; Ma, Wenjing; Nagarajan, Chandrashekhar; Tomlin, John; Vassilvitskii, Sergei; Vee, Erik; Yang, Jian

2012-01-01

125

Flexible allocation and space management in storage systems  

E-print Network

scenarios, for example: (a) space on the disk is not allocated well across multiple file systems, (b) data is not organized well for typical access patterns. We propose Virtual Allocation for flexible storage allocation. Virtual allocation separates storage...

Kang, Suk Woo

2007-09-17

126

Tax implementability of fair allocations  

Microsoft Academic Search

This paper examines the tax implementability of allocations based on fairness as no-envy (or envy-freeness) and its alternatives, by a tax schedule that depends on labor supply and gross income (( y, l)-implementability). A relevant incentive constraint is perishability of abilities, where agents can exert a lower ability level than they actually possess. We first show that in any economy,

Yukihiro Nishimura

2004-01-01

127

Industry growth and capital allocation  

Microsoft Academic Search

Are market-based or bank-based financial systems better at financing the expansion of industries that depend heavily on external finance, facilitating the formation of new establishments, and improving the efficiency of capital allocation across industries? We find evidence for neither the market-based nor the bank-based hypothesis. While legal system efficiency and overall financial development boost industry growth, new establishment formation, and

Thorsten Beck; Ross Levine

2002-01-01

128

Securing Ad Hoc Networks  

Microsoft Academic Search

Ad hoc networks are a new wireless networking paradigm for mobile hosts. Unlike traditional mobile wireless networks, ad hoc networks do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. The military tactical and other security-sensitive operations are still the main applications of ad hoc networks, although there is a trend to

Lidong Zhou; Zygmunt J. Haas

1999-01-01

129

The comparative topology of energy allocation in budget models  

NASA Astrophysics Data System (ADS)

The standard Dynamic Energy Budget (DEB) model assumes that assimilates of an isomorphic individual are first added to reserve, a fraction ? 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 ?-rule and allow ? 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 ( ?-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 ? is the only one that passes all our tests successfully. Only assimilation ( A) models can naturally accommodate embryo development. The ?-models, which after splitting the fraction 1- ? of assimilates is allocated to maturity maintenance and maturity/reproduction while the fraction ? 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.

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

2011-11-01

130

Stochastic approaches in systems biology.  

PubMed

The discrete and random occurrence of chemical reactions far from thermodynamic equilibrium, and low copy numbers of chemical species, in systems biology necessitate stochastic approaches. This review is an effort to give the reader a flavor of the most important stochastic approaches relevant to systems biology. Notions of biochemical reaction systems and the relevant concepts of probability theory are introduced side by side. This leads to an intuitive and easy-to-follow presentation of a stochastic framework for modeling subcellular biochemical systems. In particular, we make an effort to show how the notion of propensity, the chemical master equation (CME), and the stochastic simulation algorithm arise as consequences of the Markov property. Most stochastic modeling reviews focus on stochastic simulation approaches--the exact stochastic simulation algorithm and its various improvements and approximations. We complement this with an outline of an analytical approximation. The most common formulation of stochastic models for biochemical networks is the CME. Although stochastic simulations are a practical way to realize the CME, analytical approximations offer more insight into the influence of randomness on system's behavior. Toward that end, we cover the chemical Langevin equation and the related Fokker-Planck equation and the two-moment approximation (2MA). Throughout the text, two pedagogical examples are used to key illustrate ideas. With extensive references to the literature, our goal is to clarify key concepts and thereby prepare the reader for more advanced texts. PMID:20836037

Ullah, Mukhtar; Wolkenhauer, Olaf

2010-01-01

131

AdFlip.com  

NSDL National Science Digital Library

Here's a site that's both fun and useful to students of American pop culture. Billing itself "the world's largest searchable database of classic print ads," AdFlip may be keyword searched or browsed by several methods. The ads are indexed by category (automotive, electronic, fashion, etc.), decade (1940s to current), and several specialty categories (ad as art, famous, advocacy, provocative [a few nudes here], today's top ten). Each collection of ads (presented as thumbnails) can be displayed by date, name, or ID number. Each of the decade collections can be further refined by a number of categories, such as automotive manufacturers, women's fashion, alcohol, and furniture and appliances, among others.

132

BadAds  

NSDL National Science Digital Library

The creators of BadAds believe that advertising has become far too intrusive in American lives. Along with TV, magazine, radio ads, and billboards, advertisements and commercials are popping up in movie theatres, schools, public bathrooms, and even on stickers on fruit. Four criteria determine whether advertising is intrusive: an inability to turn the ad off; its entrance into your home without your consent; your lack of choice whether or not to watch it; and ads that don't support anything in particular and may actually cost you money. Rather than just venting about intrusive advertising, BadAds urges visitors to become active in the fight against bad ads by writing complaint letters to a host of venues that support intrusive advertising including movie theaters, sporting venues, television networks, and the heads of educational institutions. BadAds offers instructions on writing complaint letters as well as many suggestions as to who should receive these letters.

133

Selection of Multivariate Stochastic Volatility Models via Bayesian Stochastic Search  

Microsoft Academic Search

We propose a Bayesian stochastic search approach to selecting restrictions on multivariate regression models where the errors exhibit deterministic or stochastic conditional volatilities. We develop a Markov Chain Monte Carlo (MCMC) algorithm that generates posterior restrictions on the regression coe-cients and Cholesky decompositions of the covariance matrix of the errors. Numerical simulations with artiflcially generated data show that the proposed

Antonello Loddo; Shawn Ni; Dongchu Sun

2011-01-01

134

Winding Strings in AdS_3  

E-print Network

Correlation functions of one unit spectral flowed states in string theory on AdS_3 are considered. We present the modified Knizhnik-Zamolodchikov and null vector equations to be satisfied by amplitudes containing states in winding sector one and study their solution corresponding to the four point function including one w=1 field. We compute the three point function involving two one unit spectral flowed operators and find expressions for amplitudes of three w=1 states satisfying certain particular relations among the spins of the fields. Several consistency checks are performed.

Estanislao Herscovich; Pablo Minces; Carmen Nunez

2005-12-15

135

Warped AdS_3 Black Holes  

Microsoft Academic Search

Three dimensional topologically massive gravity (TMG) with a negative\\u000acosmological constant -\\\\ell^{-2} and positive Newton constant G admits an AdS_3\\u000avacuum solution for any value of the graviton mass \\\\mu. These are all known to\\u000abe perturbatively unstable except at the recently explored chiral point\\u000a\\\\mu\\\\ell=1. However we show herein that for every value of \\\\mu\\\\ell< 3 there are\\u000atwo

Dionysios Anninos; Wei Li; Megha Padi; Wei Song; Andrew Strominger

2008-01-01

136

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

SciTech Connect

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.

Sun Zhiyuan; Yu Xin; Liu Ying [Ministry-of-Education Key Laboratory of Fluid Mechanics and National Laboratory for Computational Fluid Dynamics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Gao Yitian [Ministry-of-Education Key Laboratory of Fluid Mechanics and National Laboratory for Computational Fluid Dynamics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); State Key Laboratory of Software Development Environment, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

2012-12-15

137

Stochastic compositional models applied to subpixel analysis of hyperspectral imagery  

NASA Astrophysics Data System (ADS)

Hyperspectral data are often modeled using either a linear mixture or a statistical classification approach. The linear mixture model describes each spectral vector as a constrained linear combination of end-member spectra, whereas the classification approach models each spectra as a realization of a random vector having one of several normal distributions. In this work we describe a stochastic compositional model that synthesizes these two viewpoints and models each spectra as a constrained linear combination of random vectors. Maximum likelihood methods of estimating the parameters of the model, assuming normally distributed random vectors, are described, and anomaly and likelihood ratio detection statistics are defined. Detection algorithms derived from the classification, linear mixing, and stochastic compositional models are defined. Detection algorithms derived from the classification, linear mixing, and stochastic compositional models are compared using data consisting of ocean hyperspectral imagery to which the signature of a personal flotation device has been added at pixel fill fractions (PFF) of five and ten percent. These results show that detection algorithms based on the stochastic compositional model may significantly improve detection performance. For example, this study shows that, at a 5% PFF and a probability of detection of 0.8, the false alarm probabilities of anomaly and likelihood detection algorithms based on the stochastic compositional model are more than an order of magnitude lower than the false alarm probabilities of comparable algorithms based on either a linear unmixing algorithm or a Gaussian mixture model.

Stein, David W. J.

2002-01-01

138

Contrasted effect of biochar and earthworms on rice growth and resource allocation in different soils  

Microsoft Academic Search

Adding biochar to soils and maintaining high earthworm biomasses are potential ways to increase the fertility of tropical soils and the sustainability of crop production in the spirit of agroecology and ecological engineering. However, a thorough functional assessment of biochar effect on plant growth and resource allocations is so far missing. Moreover, earthworms and biochar increase mineral nutrient availability through

Diana Noguera; Marco Rondón; Kam-Rigne Laossi; Valerio Hoyos; Patrick Lavelle; Maria Helena Cruz de Carvalho; Sébastien Barot

2010-01-01

139

Boson stars in AdS spacetime  

NASA Astrophysics Data System (ADS)

We construct boson stars in global anti-de Sitter (AdS) space and study their stability. Linear perturbation results suggest that the ground state along with the first three excited state boson stars are stable. We evolve some of these solutions and study their nonlinear stability in light of recent work , arguing that a weakly turbulent instability drives scalar perturbations of AdS to black hole formation. However, evolutions suggest that boson stars are nonlinearly stable and immune to the instability for sufficiently small perturbation. Furthermore, these studies find other families of initial data which similarly avoid the instability for sufficiently weak parameters. Heuristically, we argue that initial data families with widely distributed mass energy distort the spacetime sufficiently to oppose the coherent amplification favored by the instability. From the dual CFT perspective our findings suggest that there exist families of rather generic initial conditions in strongly coupled CFT (with large number of degrees of freedom) that do not thermalize in the infinite future.

Buchel, Alex; Liebling, Steven L.; Lehner, Luis

2013-06-01

140

Foliated stochastic calculus: Harmonic measures  

Microsoft Academic Search

In this article we present an intrinsec construction of foliated Brownian motion via stochastic calculus adapted to foliation. The stochastic approach together with a proposed foliated vector calculus provide a natural method to work on harmonic measures. Other results include a decomposition of the Laplacian in terms of the foliated and basic Laplacians, a characterization of totally invariant measures and

Pedro J. Catuogno; Diego S. Ledesma; Paulo R. Ruffino

2010-01-01

141

STOCHASTIC CONTROL OF BEAM DYNAMICS  

Microsoft Academic Search

The methods of stochastic control theory are proposed in the context of charged-particle beam dynamics. The stochastic dynamics that is introduced here is invariant for time reversal and can be easily recast in the form of a Schrodinger-like equation where Planck's constant is re- placed by the beam emittance. It changes a bilinear control problem for Schrodinger equation in a

N. Cufaro-Petroni; S. De Martino; F. Illuminati

142

An introduction to stochastic dynamics  

E-print Network

An introduction to stochastic dynamics and their (Bayesian) inversion Jean Daunizeau, K. Friston.3 Variational Bayesian methods for approximate learning 3 Bayesian identification of stochastic dynamical systems 3.1 Standard Bayesian techniques 3.3 A full variational Bayesian inversion scheme 4 Evaluation 5

Daunizeau, Jean

143

Stochastic Optimization for Machine Learning  

E-print Network

Stochastic Optimization for Machine Learning ICML 2010, Haifa, Israel Tutorial by Nati Srebro Descent: formulation, analysis and use in machine learning · Learn about extensions and generalizations, and their Machine Learning counterparts Main Goal: Machine Learning is Stochastic Optimization #12;Outline

Powell, Warren B.

144

Resource allocation using constraint propagation  

NASA Technical Reports Server (NTRS)

The concept of constraint propagation was discussed. Performance increases are possible with careful application of these constraint mechanisms. The degree of performance increase is related to the interdependence of the different activities resource usage. Although this method of applying constraints to activities and resources is often beneficial, it is obvious that this is no panacea cure for the computational woes that are experienced by dynamic resource allocation and scheduling problems. A combined effort for execution optimization in all areas of the system during development and the selection of the appropriate development environment is still the best method of producing an efficient system.

Rogers, John S.

1990-01-01

145

Banner Ad Placement Study  

NSDL National Science Digital Library

Webreference.com (discussed in the April 19, 1996 Scout Report) has recently added this interesting and thought-provoking resource to its site. The resource presents the results of a study of banner ad placement at webreference.com, conducted between March 25 and April 15, 1997 by three University of Michigan School of Business Administration students. The study concludes that changes in placement of banner ads affects "click-through" rates.

Doyle, Kim.; Minor, Anastasia.; Weyrich, Carolyn.

1997-01-01

146

Stochastic morphological evolution equations  

NASA Astrophysics Data System (ADS)

The inadequacy of locally defined set-valued differential equations to describe the evolution of shapes and morphological forms in biology, which are usually neither convex or nondecreasing, was recognised by J.-P. Aubin, who introduced morphological evolution equations, which are essentially nonlocally defined set-valued differential equations with the inclusion vector field also depending on the entire reachable set. This concept is extended here to the stochastic setting of set-valued Itô evolution equations in Hilbert spaces. Due to the nonanticipative nature of Itô calculus, the evolving reachable sets are nonanticipative nonempty closed random sets. The existence of solutions and their dependence on initial data are established. The latter requires the introduction of a time-oriented semi-metric in time-space variables. As a consequence the stochastic morphological evolution equations generate a deterministic nonautonomous dynamical system formulated as a two-parameter semigroup with the complication that the random subsets take values in different spaces at different time instances due to the nonanticipativity requirement. It is also shown how nucleation processes can be handled in this conceptual framework.

Kloeden, Peter E.; Lorenz, Thomas

147

Interacting stochastic oscillators  

NASA Astrophysics Data System (ADS)

Stochastic coherence (SC) and self-induced stochastic resonance (SISR) are two distinct mechanisms of noise-induced coherent motion. For interacting SC and SISR oscillators, we find that whether or not phase synchronization is achieved depends sensitively on the coupling strength and noise intensities. Specifically, in the case of weak coupling, individual oscillators are insensitive to each other, whereas in the case of strong coupling, one fixed oscillator with optimal coherence can be entrained to the other, adjustable oscillator (i.e., its noise intensity is tunable), achieving phase-locking synchronization, as long as the tunable noise intensity is not beyond a threshold; such synchronization is lost otherwise. For an array lattice of SISR oscillators, except for coupling-enhanced coherence similar to that found in the case of coupled SC oscillators, there is an optimal network topology degree (i.e., number of coupled nodes), such that coherence and synchronization are optimally achieved, implying that the system-size resonance found in an ensemble of noise-driven bistable systems can occur in coupled SISR oscillators.

Zhang, Jiajun; Yuan, Zhanjiang; Wang, Junwei; Zhou, Tianshou

2008-02-01

148

Optimizing Adaptive Control Allocation With Actuator Dynamics  

Microsoft Academic Search

In this work we address the optimizing control allocation problem for an over-actuated nonlinear time-varying system with actuator dynamic where parameters affine in the actuator and effector model may be assumed unknown. Instead of optimizing the control allocation at each time instant, a dynamic approach is considered by constructing actuator reference update-laws that represent an asymptotically optimal allocation search. By

Tor Arne Johansen

2008-01-01

149

Optimizing adaptive control allocation with actuator dynamics  

Microsoft Academic Search

In this work we address the optimizing control allocation problem for an over-actuated nonlinear time-varying system with actuator dynamic where parameters affine in the actuator and effector model may be assumed unknown. Instead of optimizing the control allocation at each time instant, a dynamic approach is considered by constructing actuator reference update-laws that represent an asymptotically optimal allocation search. By

J. Tjonnas; T. A. Johansen

2007-01-01

150

Multiple objective multiple allocation hub location problem  

Microsoft Academic Search

Hub networks are used to connect supply and demand nodes without establishing direct connections between any origin-destination nodes. The issue is to find optimum hub locations and allocate non-hub nods to them at minimum cost and\\/or travel time. Multiple allocation hub location problems deal with network in which non-hub nodes can be allocated to more than one hub. In this

Masoud Mirzaei; Mahdi Bashiri

2010-01-01

151

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

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

152

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

NASA Astrophysics Data System (ADS)

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.

Zhang, Xin-Li; Zhang, Ke-Cun

2009-09-01

153

Strings on AdS wormholes  

NASA Astrophysics Data System (ADS)

We consider the behavior of open strings on AdS wormholes in Gauss-Bonnet theory, which are the Gauss-Bonnet gravity duals of a pair of field theories. A string with both endpoints on the same side of the wormhole describes two charges within the same field theory, which exhibit Coulomb interaction for small separation. On the other hand, a string extending through the wormhole describes two charges which live in different field theories, and they exhibit a spring-like confining potential. A transition occurs when there is a pair of charges present within each field theory: for small separation each pair of charges exhibits Coulomb interaction, while for large separation the charges in the different field theories pair up and exhibit confinement. If two charges move faster than a critical speed, then they exhibit a separation gap and energy is transferred from the leading charge to the lagging one.

Ali, Mir; Ruiz, Frenny; Saint-Victor, Carlos; Vázquez-Poritz, Justin F.

2013-12-01

154

Computational models and resource allocation for supercomputers  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

155

An intelligent allocation algorithm for parallel processing  

NASA Technical Reports Server (NTRS)

The problem of allocating nodes of a program graph to processors in a parallel processing architecture is considered. The algorithm is based on critical path analysis, some allocation heuristics, and the execution granularity of nodes in a program graph. These factors, and the structure of interprocessor communication network, influence the allocation. To achieve realistic estimations of the executive durations of allocations, the algorithm considers the fact that nodes in a program graph have to communicate through varying numbers of tokens. Coarse and fine granularities have been implemented, with interprocessor token-communication duration, varying from zero up to values comparable to the execution durations of individual nodes. The effect on allocation of communication network structures is demonstrated by performing allocations for crossbar (non-blocking) and star (blocking) networks. The algorithm assumes the availability of as many processors as it needs for the optimal allocation of any program graph. Hence, the focus of allocation has been on varying token-communication durations rather than varying the number of processors. The algorithm always utilizes as many processors as necessary for the optimal allocation of any program graph, depending upon granularity and characteristics of the interprocessor communication network.

Carroll, Chester C.; Homaifar, Abdollah; Ananthram, Kishan G.

1988-01-01

156

Flowing from AdS5 to AdS3 with T 1 ,1  

NASA Astrophysics Data System (ADS)

We construct supersymmetric domain wall solutions of type IIB supergravity that interpolate between AdS5 × T 1,1 in the UV and AdS3 × 2 × S 2 × S 3 solutions in the IR. The 2 factor can be replaced with a two-torus and then the solution describes a supersymmetric flow across dimensions, similar to wrapped brane solutions. While the domain wall solutions preserve (0 , 2) supersymmetry, the AdS3 solutions in the IR have an enhanced (4 , 2) superconformal supersymmetry and are related by two T-dualities to the AdS3 × S 3 × S 3 × S 1 type IIB solutions which preserve a large (4 , 4) superconformal super-symmetry. The domain wall solutions exist within the N = 4 D = 5 gauged supergravity theory that is obtained from a consistent Kaluza-Klein truncation of type IIB supergravity on T 1,1; a feature driving the flows is that two D = 5 axion like fields, residing in the N = 4 Betti multiplet, depend linearly on the two legs of the 2 factor.

Donos, Aristomenis; Gauntlett, Jerome P.

2014-08-01

157

Aeronautical ad hoc networks  

Microsoft Academic Search

There has been an enormous growth in mobile ad hoc networks (MANETs) in land based small to medium size networks with relatively strict power and resources. In this paper the concept of ad hoc networking between aircraft is introduced, which can be considered as a novel approach in increasing the data rate and practicality of future in-flight broadband Internet access.

Ehssan Sakhaee; Abbas Jamalipour; Nei Kato

2006-01-01

158

Accelerated stochastic sampling of discrete statistical systems  

NASA Astrophysics Data System (ADS)

We propose a method to reduce the relaxation time toward equilibrium in stochastic sampling of complex energy landscapes in statistical systems with discrete degrees of freedom by generalizing the platform previously developed for continuous systems. The method starts from a master equation, in contrast to the Fokker-Planck equation for the continuous case. The master equation is transformed into an imaginary-time Schrödinger equation. The Hamiltonian of the Schrödinger equation is modified by adding a projector to its known ground state. We show how this transformation decreases the relaxation time and propose a way to use it to accelerate simulated annealing for optimization problems. We implement our method in a simplified kinetic Monte Carlo scheme and show acceleration by one order of magnitude in simulated annealing of the symmetric traveling salesman problem. Comparisons of simulated annealing are made with the exchange Monte Carlo algorithm for the three-dimensional Ising spin glass. Our implementation can be seen as a step toward accelerating the stochastic sampling of generic systems with complex landscapes and long equilibration times.

Bertalan, Zsolt; Nishimori, Hidetoshi; Orland, Henri

2010-11-01

159

Accelerated stochastic sampling of discrete statistical systems.  

PubMed

We propose a method to reduce the relaxation time toward equilibrium in stochastic sampling of complex energy landscapes in statistical systems with discrete degrees of freedom by generalizing the platform previously developed for continuous systems. The method starts from a master equation, in contrast to the Fokker-Planck equation for the continuous case. The master equation is transformed into an imaginary-time Schrödinger equation. The Hamiltonian of the Schrödinger equation is modified by adding a projector to its known ground state. We show how this transformation decreases the relaxation time and propose a way to use it to accelerate simulated annealing for optimization problems. We implement our method in a simplified kinetic Monte Carlo scheme and show acceleration by one order of magnitude in simulated annealing of the symmetric traveling salesman problem. Comparisons of simulated annealing are made with the exchange Monte Carlo algorithm for the three-dimensional Ising spin glass. Our implementation can be seen as a step toward accelerating the stochastic sampling of generic systems with complex landscapes and long equilibration times. PMID:21230616

Bertalan, Zsolt; Nishimori, Hidetoshi; Orland, Henri

2010-11-01

160

Modeling stochastic gene expression in growing cells.  

PubMed

Gene expression is an inherently noisy process. Fluctuations arise at many points in the expression of a gene, as all the salient reactions such as transcription, translation, and mRNA degradation are stochastic processes. The fluctuations become important when the cellular copy numbers of the relevant molecules (mRNA or proteins) are low. For regulated genes, a computational complication arises from the fact that protein synthesis rates depend on the concentrations of the transcription factors that regulate the corresponding genes. Because of the growing cell volume, such rates are effectively time-dependent. We deal with the effects of volume growth computationally using a rather simple method: the growth of the cell volume is incorporated in our simulations by stochastically adding small volume elements to the cell volume. As an application of this method we study a gene circuit with positive autoregulation that exhibits bistability. We show how the region of bistability becomes diminished by increasing the effect of noise via a reduced copy number of the regulatory protein. Cell volume determines the region of bistability for different noise strengths. The method is general and can also be applied to other cases where synthesis rates of proteins are regulated and an appropriate analytical description is difficult to achieve. PMID:24480713

Gomez, David; Marathe, Rahul; Bierbaum, Veronika; Klumpp, Stefan

2014-05-01

161

A Stochastic Model of Accretion  

NASA Astrophysics Data System (ADS)

Star formation occurs in flocculent, chaotic environments. Therefore the accretion rates of proto-stars moving through a cloud will not be completely smooth and contains a random noise term. Stochastic accretion can be described with a non-linear stochastic differential equation for the accretion rate, for example dm = {m}2(dt + dW), where dW describes the fluctuations. A sample of seeds growing in this model develops a mass function that follows the whole shape of the initial mass function. Both the log-normal low-mass part and the high-mass power law are a consequence of the same stochastic growth equation.

Maschberger, Thomas

162

Stochastic bridges of linear systems  

E-print Network

We study a generalization of the Brownian bridge as a stochastic process that models the position and velocity of inertial particles between the two end-points of a time interval. The particles experience random acceleration and are assumed to have known states at the boundary. Thus, the movement of the particles can be modeled as an Ornstein-Uhlenbeck process conditioned on position and velocity measurements at the two end-points. It is shown that optimal stochastic control provides a stochastic differential equation (SDE) that generates such a bridge as a degenerate diffusion process. Generalizations to higher order linear diffusions are considered.

Yongxin Chen; Tryphon Georgiou

2014-07-12

163

10 CFR 217.54 - Elements of an allocation order.  

...10 Energy 3 2014-01-01 2014-01-01 false Elements of an allocation order. 217.54 Section 217.54 Energy...PRIORITIES AND ALLOCATIONS SYSTEM Allocation Actions § 217.54 Elements of an allocation order. Each allocation order must...

2014-01-01

164

Fuzzy Raw Materials Allocation Problem  

NASA Astrophysics Data System (ADS)

Based on credibility theory, this paper presents a new raw materials allocation (RMA) model in which the demands of products and the prices of surplus products are supposed to fuzzy variables, the involved restrictions mainly include the inventory of each raw material and the production capacity of company. Since the fuzzy variables in the RMA model are usually continuous variables and the exact analytical expression of objective function cannot be obtained, traditional optimization algorithms cannot be used to solve it. Therefore, we firstly apply an approximation approach (AA) to turn the original infinite-dimensional optimization problem into an approximating finite-dimensional one, then design a hybrid algorithm which combines neural network (NN) and particle swarm optimization (PSO) to solve the approximating model. A given numerical example illustrates that the designed algorithm works well.

Sun, Gao-Ji

165

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

PubMed

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

Yu, Chao; Sharma, Gaurav

2010-08-01

166

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

167

Stochastic Resonance: from climate to biology  

E-print Network

In this paper I will review some basic aspects of the mechanism of stochastic resonance. Stochastic resonance was first introduced as a possible mechanism to explain long term climatic variation. Since then, there have been many applications of stochastic resonance in physical and biological systems. I will show that in complex system, stochastic resonance can substantially change as a function of the ``system complexity''. Also, I will briefly mention how to apply stochastic resonance for the case of Brownian motors.

Roberto Benzi

2007-02-05

168

Reward structures and the allocation of talent  

Microsoft Academic Search

As relative rewards that different professions receive are a key factor in the allocation of talent, what determines the reward structure of a society is an important question. This paper develops an equilibrium model of the allocation of talent between productive and unproductive activities (such as rent-seeking). The existence of rent-seeking creates a negative externality on productive agents and implies

Daron Acemoglu

1995-01-01

169

Resource Allocation in Public Research Universities  

ERIC Educational Resources Information Center

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)…

Santos, Jose L.

2007-01-01

170

Prophet Address Allocation for Large Scale MANETs  

Microsoft Academic Search

A mobile device in a MANET must be assigned a free IP address before it may participate in unicast communi- cation. This is a fundamental and difficult problem in the practical use of any MANET. Several solutions have been proposed. However, these approaches have different drawbacks. A new IP address allocation algorithm, namely pro- phet address allocation, is proposed in

Hongbo Zhou; Lionel M. Ni; Matt W. Mutka

2003-01-01

171

Space allocation using intelligent optimization techniques  

Microsoft Academic Search

The space allocation problem has taken an important role in different fields. For instance, placing items in a warehouse where it is essential to take advantage of the available space and meet the production requirements. Similarly, the parking slot allocation for automobiles in a car parking in which there are occasions where a lack of proper distribution of the automobiles

E. R. Q. Garcia; G. C. M. Quintero

2010-01-01

172

Task allocation for wide area search munitions  

Microsoft Academic Search

Addresses the problem of task allocation for wide area search munitions. The munitions are required to search for, classify, attack, and perform battle damage assessment on potential targets. It is assumed that target field information is communicated between all elements of the swarm. A network flow optimization model is used to develop a linear program for optimal resource allocation. Periodically

Corey Schumacher; Phillip R. Chandler; S. R. Rasmussen

2002-01-01

173

Sex allocation: evolution to and from dioecy.  

PubMed

Sex allocation in hermaphrodites should evolve in response to changes in the frequency of unisexuals. As predicted, it has now been demonstrated that hermaphrodites respond to the removal of males from experimental plant populations by increasing their allocation to male function. PMID:19321140

Delph, Lynda F

2009-03-24

174

Justice in Grades Allocation: Teachers' Perspective  

ERIC Educational Resources Information Center

In this investigation I explore teachers' perspectives on just grade allocation. The study was carried out among language, math and science teachers in a national sample of Israeli high schools, where teachers were required to weigh a set of considerations that are used in the decision on grade allocation. Findings suggest that (a) a teacher's…

Resh, Nura

2009-01-01

175

GSA: scheduling and allocation using genetic algorithm  

Microsoft Academic Search

This paper describes a unique approach to scheduling and allocation problem in high-level synthesis using genetic algorithm (GA). This approach is different from a previous attempt using GA [l] in many respects. Our contributions include: a new chromosomal representation for scheduling and two subproblems of allocation; and two novel crossover operators to generate legal schedules. The approach has been tested

Ali Shahid; Muhammed S. T. Benten; Sadiq M. Sait

1994-01-01

176

A Time Allocation Study of University Faculty  

ERIC Educational Resources Information Center

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…

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

2008-01-01

177

Optimal thrust allocation for marine vessels  

Microsoft Academic Search

This paper presents a new thrust-allocation scheme which significantly reduces the fuel consumption for dynamic positioning of ships when rotatable azimuth thrusters are used. Thrust allocation is the problem of determining the thrust and the direction of each of the n thruster devices of a ship, given the desired forces and moment from the control law. The problem of singular

O. J. Sørdalen

1997-01-01

178

50 CFR 660.55 - Allocations.  

Code of Federal Regulations, 2013 CFR

...allocations. Prior to the setting of fishery allocations, the TAC, ACL, or ACT when specified, is reduced by the Pacific Coast...treaty Indian fisheries, set-asides will be deducted from the TAC, OY, ACL, or ACT when specified. For the...

2013-10-01

179

UNIVERSITY SPACE POLICY ALLOCATION OF UNIVERSITY SPACE  

E-print Network

UNIVERSITY COLLEGE DUBLIN UNIVERSITY SPACE POLICY #12;ALLOCATION OF UNIVERSITY SPACE I Purpose To provide a methodology for the allocation of space across the University II Background Due to the university's success in attracting research funding, the need for space and facilities has grown

180

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)

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 ?-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).

Bekri, Eleni; Yannopoulos, Panayotis; Disse, Markus

2013-04-01

181

Bioethics for clinicians: 13. Resource allocation  

PubMed Central

Questions of resource allocation can pose practical and ethical dilemmas for clinicians. In the Aristotelian conception of distributive justice, the unequal allocation of a scarce resource may be justified by morally relevant factors such as need or likelihood of benefit. Even using these criteria, it can be difficult to reconcile completing claims to determine which patients should be given priority. To what extent the physician's fiduciary duty toward a patient should supersede the interests of other patients and society as a whole is also a matter of controversy. Although the courts have been reluctant to become involved in allocation decisions in health care, they expect physicians to show allegiance to their patients regardless of budgetary concerns. The allocation of resources on the basis of clinically irrelevant factors such as religion or sexual orientation is prohibited. Clear, fair and publicly acceptable institutional and professional policies can help to ensure that resource allocation decisions are transparent and defensible. PMID:9238146

McKneally, M F; Dickens, B M; Meslin, E M; Singer, P A

1997-01-01

182

Statistical validation of stochastic models  

SciTech Connect

It is common practice in structural dynamics to develop mathematical models for system behavior, and the authors are now capable of developing stochastic models, i.e., models whose parameters are random variables. Such models have random characteristics that are meant to simulate the randomness in characteristics of experimentally observed systems. This paper suggests a formal statistical procedure for the validation of mathematical models of stochastic systems when data taken during operation of the stochastic system are available. The statistical characteristics of the experimental system are obtained using the bootstrap, a technique for the statistical analysis of non-Gaussian data. The authors propose a procedure to determine whether or not a mathematical model is an acceptable model of a stochastic system with regard to user-specified measures of system behavior. A numerical example is presented to demonstrate the application of the technique.

Hunter, N.F. [Los Alamos National Lab., NM (United States). Engineering Science and Analysis Div.; Barney, P.; Paez, T.L. [Sandia National Labs., Albuquerque, NM (United States). Experimental Structural Dynamics Dept.; Ferregut, C.; Perez, L. [Univ. of Texas, El Paso, TX (United States). Dept. of Civil Engineering

1996-12-31

183

Stochastic Climate Theory and Modelling  

E-print Network

Stochastic methods are a crucial area in contemporary climate research and are increasingly being used in comprehensive weather and climate prediction models as well as reduced order climate models. Stochastic methods are used as subgrid-scale parameterizations as well as for model error representation, uncertainty quantification, data assimilation and ensemble prediction. The need to use stochastic approaches in weather and climate models arises because we still cannot resolve all necessary processes and scales in comprehensive numerical weather and climate prediction models. In many practical applications one is mainly interested in the largest and potentially predictable scales and not necessarily in the small and fast scales. For instance, reduced order models can simulate and predict large scale modes. Statistical mechanics and dynamical systems theory suggest that in reduced order models the impact of unresolved degrees of freedom can be represented by suitable combinations of deterministic and stochast...

Franzke, Christian L E; Berner, Judith; Williams, Paul D; Lucarini, Valerio

2014-01-01

184

Stochastic thermodynamics: principles and perspectives  

NASA Astrophysics Data System (ADS)

Stochastic thermodynamics provides a framework for describing small systems like colloids or biomolecules driven out of equilibrium but still in contact with a heat bath. Both, a first-law like energy balance involving exchanged heat and entropy production entering refinements of the second law can consistently be defined along single stochastic trajectories. Various exact relations involving the distribution of such quantities like integral and detailed fluctuation theorems for total entropy production and the Jarzynski relation follow from such an approach based on Langevin dynamics. Analogues of these relations can be proven for any system obeying a stochastic master equation like, in particular, (bio)chemically driven enzyms or whole reaction networks. The perspective of investigating such relations for stochastic field equations like the Kardar-Parisi-Zhang equation is sketched as well.

Seifert, U.

2008-08-01

185

Ad Hoc Advisors  

Cancer.gov

The Long Island Breast Cancer Study Project (LIBCSP) had an Ad Hoc Advisory Committee of expert scientists and community breast cancer advocates. This committee was chaired by Dr. Mimi C. Yu. The committee met annually or as needed.

186

Adding Two Vectors  

NSDL National Science Digital Library

This website from David M. Harrison of the University of Toronto's physics department provides an animation of the addition of two vectors. Instructors may use this animation in explaining the concept of adding vectors and demonstrating the steps involved.

Harrison, David M.

2010-08-13

187

Carbon allocation and accumulation in conifers  

SciTech Connect

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.

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

1995-07-01

188

Stochastic superparameterization in quasigeostrophic turbulence  

NASA Astrophysics Data System (ADS)

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 ?-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.

Grooms, Ian; Majda, Andrew J.

2014-08-01

189

Foliated stochastic calculus: Harmonic measures  

Microsoft Academic Search

In this article we present an intrinsec construction of foliated Brownian\\u000amotion via stochastic calculus adapted to foliation. The stochastic approach\\u000atogether with a proposed foliated vector calculus provide a natural method to\\u000awork on harmonic measures. Other results include a decomposition of the\\u000aLaplacian in terms of the foliated and basic Laplacians, a characterization of\\u000atotally invariant measures and

Pedro J. Catuogno; Diego S. Ledesma; Paulo R. Ruffino

2010-01-01

190

Schwinger Mechanism with Stochastic Quantization  

E-print Network

We prescribe a formulation of the particle production with real-time Stochastic Quantization. To construct the retarded and the time-ordered propagators we decompose the stochastic variables into positive- and negative-energy parts. In this way we demonstrate how to derive a standard formula for the Schwinger mechanism under time-dependent electric fields. We discuss a mapping to the Schwinger-Keldysh formalism and a relation to the classical statistical simulation.

Kenji Fukushima; Tomoya Hayata

2014-03-17

191

Stochastic Trends and Economic Fluctuations  

Microsoft Academic Search

Are business cycles mainly the result of permanent shocks to productivity? This paper uses a long-run restriction implied by a large class of real-business-cycle models--identifying permanent productivity shocks as shocks to the common stochastic trend in output, consumption, and investment--to provide new evidence on this question. Econometric tests indicate that this common-stochastic-trend\\/cointegration implication is consistent with postwar U.S. data. However,

Robert G. King; Charles I. Plosser; James H. Stock; Mark W. Watson

1991-01-01

192

Fully Parallel Stochastic LDPC Decoders  

Microsoft Academic Search

Stochastic decoding is a new approach to iterative decoding on graphs. This paper presents a hardware architecture for fully parallel stochastic low-density parity-check (LDPC) de- coders. To obtain the characteristics of the proposed architecture, we apply this architecture to decode an irregular state-of-the-art (1056,528) LDPC code on a Xilinx Virtex-4 LX200 field-pro- grammable gate-array (FPGA) device. The implemented decoder achieves

Saeed Sharifi Tehrani; Shie Mannor; Warren J. Gross

2008-01-01

193

Stochastic resonance with matched filtering  

E-print Network

Along with the development of interferometric gravitational wave detector, we enter into an epoch of gravitational wave astronomy, which will open a brand new window for astrophysics to observe our universe. Almost all of the data analysis methods in gravitational wave detection are based on matched filtering. Gravitational wave detection is a typical example of weak signal detection, and this weak signal is buried in strong instrument noise. So it seems attractable if we can take advantage of stochastic resonance. But unfortunately, almost all of the stochastic resonance theory is based on Fourier transformation and has no relation to matched filtering. In this paper we try to relate stochastic resonance to matched filtering. Our results show that stochastic resonance can indeed be combined with matched filtering for both periodic and non-periodic input signal. This encouraging result will be the first step to apply stochastic resonance to matched filtering in gravitational wave detection. In addition, based on matched filtering, we firstly proposed a novel measurement method for stochastic resonance which is valid for both periodic and non-periodic driven signal.

Li-Fang Li; Jian-Yang Zhu

2010-06-28

194

48 CFR 18.109 - Priorities and allocations.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Priorities and allocations. 18...REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY...Flexibilities 18.109 Priorities and allocations. The Defense Priorities and Allocations...

2010-10-01

195

42 CFR 121.8 - Allocation of organs.  

Code of Federal Regulations, 2011 CFR

...Special rule for initial revision of liver allocation policies. When the OPTN transmits...the Secretary its initial revision of the liver allocation policies, as directed by...would have been treated had the revised liver allocation policies not become...

2011-10-01

196

42 CFR 121.8 - Allocation of organs.  

Code of Federal Regulations, 2010 CFR

...Special rule for initial revision of liver allocation policies. When the OPTN transmits...the Secretary its initial revision of the liver allocation policies, as directed by...would have been treated had the revised liver allocation policies not become...

2010-10-01

197

42 CFR 121.8 - Allocation of organs.  

Code of Federal Regulations, 2012 CFR

...Special rule for initial revision of liver allocation policies. When the OPTN transmits...the Secretary its initial revision of the liver allocation policies, as directed by...would have been treated had the revised liver allocation policies not become...

2012-10-01

198

42 CFR 121.8 - Allocation of organs.  

Code of Federal Regulations, 2013 CFR

...Special rule for initial revision of liver allocation policies. When the OPTN transmits...the Secretary its initial revision of the liver allocation policies, as directed by...would have been treated had the revised liver allocation policies not become...

2013-10-01

199

50 CFR 679.62 - Inshore sector cooperative allocation program.  

Code of Federal Regulations, 2012 CFR

...cooperative permit. (3) Conversion of quota share percentage to TAC allocations. (Effective April 1, 2005) Each inshore pollock...allocation for that subarea. Each cooperative's annual pollock TAC allocation may be published in the proposed and final BSAI...

2012-10-01

200

50 CFR 679.62 - Inshore sector cooperative allocation program.  

Code of Federal Regulations, 2013 CFR

...cooperative permit. (3) Conversion of quota share percentage to TAC allocations. (Effective April 1, 2005) Each inshore pollock...allocation for that subarea. Each cooperative's annual pollock TAC allocation may be published in the proposed and final BSAI...

2013-10-01

201

50 CFR 679.62 - Inshore sector cooperative allocation program.  

Code of Federal Regulations, 2011 CFR

...cooperative permit. (3) Conversion of quota share percentage to TAC allocations. (Effective April 1, 2005) Each inshore pollock...allocation for that subarea. Each cooperative's annual pollock TAC allocation may be published in the proposed and final BSAI...

2011-10-01

202

Stochastic Inflation: New Results  

E-print Network

This is an old article which has never been posted for public use and which only appeard in a relatively hard-to-get Proceedings of the Sakharov Conference in Moscow (May, 1991). The subject of this article has received a lot of attention in last two years. Although we acknowledge that there has been a very big progress in the field of relating the spectrum of fluctuations to scalar field potentials of inflation models, which have outdated some of our results (particularly because we never took into account the tensor fluctuations which have been shown to be crucial for reconstructing the inflaton potential) we think that some of the other ideas and approaches which we presented in this article maybe still of interest. We did not rewrite the article to include any of the newer approaches and we did not add any of the newer references. The reader is advised to refer to recent papers (for example, see the paper astro-ph/9403001 by Edward Kolb and Sharon Vadas) for state of the art review and up-to-date references. ==The original abstract of the article==: We prove that, in stochastic approach, there exists an equivalence relation between different inflationary models under some redefinition of field and time variables. The postinflationary physics is insensitive to it and one can say that related theories are in fact indistinguishable from the viewpoint

A. Mezhlumian; A. Starobinsky

1994-06-14

203

Stochastic pooling networks  

NASA Astrophysics Data System (ADS)

We introduce and define the concept of a stochastic pooling network (SPN), as a model for sensor systems where redundancy and two forms of 'noise'—lossy compression and randomness—interact in surprising ways. Our approach to analysing SPNs is information theoretic. We define an SPN as a network with multiple nodes that each produce noisy and compressed measurements of the same information. An SPN must combine all these measurements into a single further compressed network output, in a way dictated solely by naturally occurring physical properties—i.e. pooling—and yet cause no (or negligible) reduction in mutual information. This means that SPNs exhibit redundancy reduction as an emergent property of pooling. The SPN concept is applicable to examples in biological neural coding, nanoelectronics, distributed sensor networks, digital beamforming arrays, image processing, multiaccess communication networks and social networks. In most cases the randomness is assumed to be unavoidably present rather than deliberately introduced. We illustrate the central properties of SPNs for several case studies, where pooling occurs by summation, including nodes that are noisy scalar quantizers, and nodes with conditionally Poisson statistics. Other emergent properties of SPNs and some unsolved problems are also briefly discussed.

McDonnell, Mark D.; Amblard, Pierre-Olivier; Stocks, Nigel G.

2009-01-01

204

Linear modelling of attentional resource allocation  

NASA Technical Reports Server (NTRS)

Eight subjects time-shared performance of two compensatory tracking tasks under conditions when both were of constant difficulty, and when the control order of one task (designated primary) was varied over time within a trial. On line performance feedback was presented on half of the trials. The data are interpreted in terms of a linear model of the operator's attention allocation system, and suggest that this allocation is strongly suboptimal. Furthermore, the limitations in reallocating attentional resources between tasks, in response to difficulty fluctuations were not reduced by augmented performance feedback. Some characteristics of the allocation system are described, and reasons for its limitations suggested.

Pierce, B.

1978-01-01

205

D-branes on AdS flux compactifications  

Microsoft Academic Search

We study D-branes in Script N = 1 flux compactifications to AdS4. We derive their supersymmetry conditions and express them in terms of background generalized calibrations. Basically because AdS has a boundary, the analysis of stability is more subtle and qualitatively different from the usual case of Minkowski compactifications. For instance, stable D-branes filling AdS4 may wrap trivial internal cycles.

Paul Koerber; Luca Martucci

2008-01-01

206

Declarative ad-hoc sensor networking  

NASA Astrophysics Data System (ADS)

Networking protocols for distributed collaborative ad-hoc wireless sensing are constrained by requirements such as energy efficiency, scalability, and support for greater variations in topology than traditional fully wired or last- hop wireless (remote to base station) networks. In such a highly constrained and dynamic environment, conventional networking approaches are generally not adequate. A declarative approach to network configuration and organization appears to offer significant benefits. Declarative networking exploits application-supplied data descriptions to control network routing and resource allocation in such a way as to enhance energy efficiency and scalability. An implementation of this approach, called the Declarative Routing Protocol (DRP) has been developed as part of DARPA's Sensor Information Technology program. This paper introduces the concept of declarative networking and what distinguishes it from more conventional networking approaches, describes the Declarative Routing Protocol, and presents performance results from initial experiments.

Coffin, Daniel A.; Van Hook, Daniel J.; McGarry, Stephen M.; Kolek, Stephen R.

2000-11-01

207

Stacking with stochastic cooling  

NASA Astrophysics Data System (ADS)

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 10 5 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.

Caspers, Fritz; Möhl, Dieter

2004-10-01

208

Enhanced algorithms for stochastic programming  

SciTech Connect

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.

Krishna, A.S.

1993-09-01

209

Stochastic models: theory and simulation.  

SciTech Connect

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.

Field, Richard V., Jr.

2008-03-01

210

A stochastic analysis approach for the calculation of hydrodynamic dampings  

SciTech Connect

This paper introduces an alternative linearization algorithm for nonlinear loading terms occurring in the spectral analysis of offshore structures. The algorithm makes use of member consistent forces for the linearization unlike the traditional linearization method. Different linearization criteria are used for different components of the member consistent forces. An equivalent second moment criterion is used to linearize the force component due to wave velocities while the components due to current and structural velocities are kept being stochastic. Calculation of their mean values is presented for the analysis. A deterministic added mass matrix and a stochastic hydrodynamic damping matrix are derived from the force component due to structural deformations. It is demonstrated that the mean value hydrodynamic damping ratios which are calculated in the paper are more realistic than those resulted from the linearization of the Morison`s equation.

Karadeniz, H. [Delft Univ. of Technology (Netherlands). Dept. of Civil Engineering

1995-12-31

211

Essays on innovation, productivity, and talent allocation  

E-print Network

This thesis contains three essays on innovation, productivity, and talent allocation. The first essay explores a novel channel through which short-term economic fluctuations affect the long-term innovative output of the ...

Shu, Pian

2012-01-01

212

ORIGINAL PAPER Photosynthetic assimilation and carbohydrate allocation  

E-print Network

ORIGINAL PAPER Photosynthetic assimilation and carbohydrate allocation of Quercus rubra seedlings increases in biomass and total non- structural carbohydrates (TNC), stock type differences to herbivory- mental. Keywords Animal browse . Northern red oak . Non-structural carbohydrates . Planting stock types

Boyer, Edmond

213

Internal Markets for Supply Chain Capacity Allocation  

E-print Network

This paper explores the possibility of solving supply chain capacity allocation problems using internal markets among employees of the same company. Unlike earlier forms of transfer pricing, IT now makes it easier for such ...

McAdams, David

2005-07-08

214

Decentralized task allocation for dynamic environments  

E-print Network

This thesis presents an overview of the design process for creating greedy decentralized task allocation algorithms and outlines the main decisions that progressed the algorithm through three different forms. The first ...

Johnson, Luke B

2012-01-01

215

10 CFR 490.503 - Credit allocation.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Alternative Fueled Vehicle Credit Program § 490.503...part, DOE shall allocate one credit for each alternative fueled vehicle a fleet or covered...

2010-01-01

216

48 CFR 5452.249 - Allocation.  

Code of Federal Regulations, 2011 CFR

...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...

2011-10-01

217

Fund allocation using capacitated vehicle routing problem  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

218

Asynchronous Decentralized Task Allocation for Dynamic Environments  

E-print Network

This work builds on a decentralized task allocation algorithm for networked agents communicating through an asynchronous channel, by extending the Asynchronous Consensus-Based Bundle Algorithm (ACBBA) to account for more ...

Johnson, Luke B.

219

Optimal dynamic bandwidth allocation for complex networks  

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

220

25 CFR 39.902 - Allocation.  

Code of Federal Regulations, 2010 CFR

(a) Interim Maintenance and Minor Repair funds shall be allocated to all Bureau operated and contract schools based on the number of square feet of floor space used for that school's educational program, for student residence and for support...

2010-04-01

221

Adaptively Parallel Processor Allocation for Cilk Jobs  

E-print Network

The problem of allocating processor resources fairly and efficiently to parallel jobs has been studied extensively in the past. Most of this work, however, assumes that the instantaneous parallelism of the jobs is known ...

Sen, Siddhartha

222

45 CFR 98.55 - Cost allocation.  

Code of Federal Regulations, 2011 CFR

...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 subgrantees...

2011-10-01

223

45 CFR 98.55 - Cost allocation.  

Code of Federal Regulations, 2012 CFR

...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 subgrantees...

2012-10-01

224

45 CFR 98.55 - Cost allocation.  

Code of Federal Regulations, 2010 CFR

...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 subgrantees...

2010-10-01

225

45 CFR 98.55 - Cost allocation.  

Code of Federal Regulations, 2013 CFR

...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 subgrantees...

2013-10-01

226

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...

227

Ad Astra Magazine  

NSDL National Science Digital Library

Ad Astra ("To the Stars") is the award-winning magazine of the National Space Society. It features space exploration news and full-color photography. It is published quarterly and mailed to all National Space Society members as part of their membership benefits, as well as to subscriber libraries, schools, and businesses.

2005-04-25

228

ad hoc networks.\\  

Microsoft Academic Search

Purpose – Mobile ad hoc networks rely on cooperation to perform essential network mechanisms such as routing. Therefore, network performance depends to a great extent on giving participating nodes an incentive for cooperation. The level of trust among nodes is the most frequently used parameter for promoting cooperation in distributed systems. There are different models for representing trust, each of

Marcela Mejia; Néstor M. Peña; Jose L. Muñoz; Oscar Esparza

2009-01-01

229

Cost and efficiency in nursing homes: a stochastic frontier approach.  

PubMed

The average level of cost inefficiency in New York nursing homes is estimated at 29%, based on a two-year panel of 164 Skilled Nursing Facilities and 443 combination Skilled and Health Related Facilities. The stochastic frontier cost function is fit to the data utilizing the composed error model, wherein statistical noise and allocative and technical inefficiency are jointly estimated. There is no change in efficiency between 1987 and 1990, and it does not vary between for-profit and not-for-profit homes. Excessive managerial and supervisory personnel and diseconomies of size are linked to inefficient operation. Chronic excess demand is suggested as a cause of the high level of inefficiency. PMID:10138855

Vitaliano, D F; Toren, M

1994-10-01

230

Rate allocation in a remote control structure  

E-print Network

RATE ALLOCATION IN A REMOTE CONTROL STRUCTURE A Thesis by CHARLES JOE MEADOW, JR. Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE May 1984 Major Subject...: Electrical Engineering RATE ALLOCATION IN A REMOTE CONTROL STRUCTURE A Thesis by CHARLES JOE MEADOW, JR. Approved as to style and content by: Thomas R. Fischer (Chairman of Committee) erry . Gibson ( ember) P. Frederick Dahm (Member) William B...

Meadow, Charles Joe

2012-06-07

231

Neural-Network Processor Would Allocate Resources  

NASA Technical Reports Server (NTRS)

Global optimization problems solved quickly. Neural-network processor optimizes allocation of M resources among N expenditures according to cost of pairing each resource with each expenditure and subject to limit on number of resources feeding into each expenditure and/or limit on number of expenditures to which each resource allocated. One cell performs several analog and digital functions. Potential applications include assignment of jobs, scheduling, dispatching, and planning of military maneuvers.

Eberhardt, Silvio P.; Moopenn, Alexander W.

1990-01-01

232

Self-Optimization Energy Management Considering Stochastic Influences for a Hybrid  

E-print Network

management, hybrid energy storage system, self-optimization I. INTRODUCTION TODAY'S electric and hybridSelf-Optimization Energy Management Considering Stochastic Influences for a Hybrid Energy Storage- ergy storage. By hybridization of the storage, adding double layer capacitors, the battery can

Paderborn, Universität

233

Stochastic Performance Guarantees for Mixed Workloads in a Multimedia Information System  

Microsoft Academic Search

We present an approach to stochastic performance guar- antees for multimedia servers with mixed workloads. Ad- vanced multimedia applications such as digital libraries or teleteaching exhibit a mixed workload with accesses to both 'continuous' and conventional, 'discrete' data, where the fractions of continuous-data and discrete-data requests vary over time. We assume that a server shares all disks among continuous and

Guido Nerjest; Peter Muth; Gerhard Weikum

1997-01-01

234

Numerical Stochastic Homogenization Method and Multiscale Stochastic Finite Element Method - A Paradigm for Multiscale Computation of Stochastic PDEs  

Microsoft Academic Search

Multiscale modeling of stochastic systems, or uncertainty quantization of multiscale modeling is becoming an emerging research frontier, with rapidly growing engineering applications in nanotechnology, biotechnology, advanced materials, and geo-systems, etc. While tremendous efforts have been devoted to either stochastic methods or multiscale methods, little combined work had been done on integration of multiscale and stochastic methods, and there was no

X. Frank Xu

2010-01-01

235

Introducing ADS Labs  

NASA Astrophysics Data System (ADS)

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

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

236

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

PubMed

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

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

2014-03-01

237

Stochasticity, succession, and environmental perturbations in a fluidic ecosystem  

PubMed Central

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

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

238

Allocation of authority in European health policy.  

PubMed

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

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

2012-11-01

239

Principal axes for stochastic dynamics  

NASA Astrophysics Data System (ADS)

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.

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

2011-09-01

240

Nonlinear optimization for stochastic simulations.  

SciTech Connect

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.

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

2003-12-01

241

Stochastic modeling of cellular networks.  

PubMed

Noise and stochasticity are fundamental to biology because they derive from the nature of biochemical reactions. Thermal motions of molecules translate into randomness in the sequence and timing of reactions, which leads to cell-cell variability ("noise") in mRNA and protein levels even in clonal populations of genetically identical cells. This is a quantitative phenotype that has important functional repercussions, including persistence in bacterial subpopulations challenged with antibiotics, and variability in the response of cancer cells to drugs. In this chapter, we present the modeling of such stochastic cellular behaviors using the formalism of jump Markov processes, whose probability distributions evolve according to the chemical master equation (CME). We also discuss the techniques used to solve the CME. These include kinetic Monte Carlo simulations techniques such as the stochastic simulation algorithm (SSA) and method closure techniques such as the linear noise approximation (LNA). PMID:22482947

Stewart-Ornstein, Jacob; El-Samad, Hana

2012-01-01

242

Some Stochastic Aspects of Intergranular Creep Cavitation.  

National Technical Information Service (NTIS)

We present some results obtained from a simplified stochastic model of intergranular creep cavitation. The probabilistic features of the model arise from the inclusion of random cavity placement on the grain boundary and time-discrete stochastic cavity nu...

S. J. Fariborz, J. P. Farris, D. G. Harlow, T. J. Delph

1987-01-01

243

Bayesian Statistics Stochastic Simulation -Gibbs sampling  

E-print Network

Bayesian Statistics Stochastic Simulation - Gibbs sampling Bayesian Statistics - an Introduction Dr Pettit Bayesian Statistics - an Introduction #12;Bayesian Statistics Stochastic Simulation - Gibbs sampling What is Bayesian Statistics? Bayes Theorem The Likelihood Principle Mixtures of conjugate priors

Wright, Francis

244

CMOS-compatible active thermopiles for noise-added theory  

NASA Astrophysics Data System (ADS)

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 1.2?m 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.

Shen, Chih-Hsiung; Hou, Kuan-Chou

2004-05-01

245

A Stochastic Approach to Measuring the Robustness of Resource Allocations in Distributed Systems  

E-print Network

­1373 Email: {shestak, hj, aam}@engr.colostate.edu. IBM 6300 Diagonal Highway Boulder, CO 80301 Email: bigfun@us in the face of failures, time-varying load, and various errors." The research at the User-Centered Robust- odically updated data sets, e.g., surveillance for homeland security, monitoring vital signs of medical

Maciejewski, Anthony A.

246

The Hamiltonian Mechanics of Stochastic Acceleration  

SciTech Connect

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.

Burby, J. W.

2013-07-17

247

Stochastic Inflation and Inflationary Density Fluctuations  

Microsoft Academic Search

We examine the stochastic dynamics of chaotic inflation. The nonlinear stochastic behavior of inflation is studied with an emphasis on possible non-Gaussian statistics in initial conditions for cosmological large scale structure formation. Large scale non-random phase correlations and interesting dynamical features are analyzed using stochastic dynamics. We solve the stochastic evolution equations for the inflation field during the slow-roll period

In Su. Yi

1992-01-01

248

Stochastic decision analysis  

NASA Technical Reports Server (NTRS)

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.

Lacksonen, Thomas A.

1994-01-01

249

QB1 - Stochastic Gene Regulation  

SciTech Connect

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.

Munsky, Brian [Los Alamos National Laboratory

2012-07-23

250

Schwinger Mechanism with Stochastic Quantization  

E-print Network

We prescribe a formulation of the particle production with real-time Stochastic Quantization. To construct the retarded and the time-ordered propagators we decompose the stochastic variables into positive- and negative-energy parts. In this way we demonstrate how to derive the Schwinger mechanism under a time-dependent electric field. We also discuss a physical interpretation with help of numerical simulations and develop an analogue to the one-dimensional scattering with the non-relativistic Schroedinger equation. We can then reformulate the Schwinger mechanism as the high-energy quantum reflection problem rather than tunneling.

Fukushima, Kenji

2014-01-01

251

Stochastic Simulation of Turing Patterns  

NASA Astrophysics Data System (ADS)

We investigate the effects of intrinsic noise on Turing pattern formation near the onset of bifurcation from the homogeneous state to Turing pattern in the reaction-diffusion Brusselator. By performing stochastic simulations of the master equation and using Gillespie's algorithm, we check the spatiotemporal behaviour influenced by internal noises. We demonstrate that the patterns of occurrence frequency for the reaction and diffusion processes are also spatially ordered and temporally stable. Turing patterns are found to be robust against intrinsic fluctuations. Stochastic simulations also reveal that under the influence of intrinsic noises, the onset of Turing instability is advanced in comparison to that predicted deterministically.

Fu, Zheng-Ping; Xu, Xin-Hang; Wang, Hong-Li; Ouyang, Qi

2008-04-01

252

Stochastic current drive by wave  

SciTech Connect

A new mechanism of current drive by a wave is discussed. There are a series of resonant regions in the velocity space for a magnetized plasma interacting with a single wave. When the amplitude of the wave is larger than a threshold, some of the resonant regions will overlap each other and the stochastic effect will appear. If the overlapping region is asymmetric in the longitudinal velocity distribution of the electrons, a plasma current may be driven by the wave as a result of the stochastic effect.

Xia Meng-fen

1983-10-01

253

Ad Element Liking and Its Relationship to Overall Ad Liking  

Microsoft Academic Search

This study explored differences in affective response content across three cultures and the role of these responses in predicting overall advertising liking. Based on a field survey, subjects from England, Norway and Spain evaluated cosmetic ads on a series of liking scales. Ad content was coded into elements reflecting product- or ad-related affect based on existing theory on ad evaluation

Rune Bjerke; Tom Rosendahl; Pradeep Gopalakrishna; Dennis Sandler

2006-01-01

254

A Heuristic Genetic Algorithm for Solving Resource Allocation Problems  

Microsoft Academic Search

In the paper, a heuristic genetic algorithm for solving resource allocation problems is proposed. The resource allocation problems are to allocate resources to activities so that the fitness becomes as optimal as possible. The objective of this paper is to develop an efficient algorithm to solve resource allocation problems encountered in practice. Various genetic algorithms are studied and a heuristic

Zne-Jung Lee; Shun-Feng Su; Chou-Yuan Lee; Yao-Shan Hung

2003-01-01

255

Title: Ontario Wind Power Allocation Ontario Ministry of Natural Resources  

E-print Network

Title: Ontario Wind Power Allocation Data Creator / Copyright Owner: Ontario Ministry of Natural/A Updates: N/A Abstract: This data consists of a polygon shapefile, Wind Power Allocation Block. A Wind Power Allocation Block is an area that could be allocated for the exploration of wind power generation

256

Stochastic averaging using elliptic functions to study nonlinear stochastic systems  

Microsoft Academic Search

In this paper, a new scheme of stochastic averaging using elliptic functions is presented that approximates nonlinear dynamical systems with strong cubic nonlinearities in the presence of noise by a set of Itô differential equations. This is an extension of some recent results presented in deterministic dynamical systems. The second order nonlinear differential equation that is examined in this work

Win-Min Tien; N. Sri Namachchivaya; V. T. Coppola

1993-01-01

257

A Stochastic Model of Airline Operations  

Microsoft Academic Search

We present a stochastic model of the daily operations of an airline. Its primary purpose is to evaluate plans, such as crew schedules, as well as recovery policies in a ran- dom environment. We describe the structure of the stochastic model, sources of disruptions, recovery policies, and performance measures. Then, we describe SimAir—our simulation implementation of the stochastic model, and

Jay M. Rosenberger; Andrew J. Schaefer; David Goldsman; Ellis L. Johnson; Anton J. Kleywegt; George L. Nemhauser

2002-01-01

258

3, 453483, 2012 A stochastic model  

E-print Network

ESDD 3, 453­483, 2012 A stochastic model for the polygonal tundra F. Cresto Aleina et al. Title paper in ESD if available. A stochastic model for the polygonal tundra based on Poisson-Voronoi Diagrams­483, 2012 A stochastic model for the polygonal tundra F. Cresto Aleina et al. Title Page Abstract

Zuyev, Sergei

259

A Learning Criterion for Stochastic Rules  

Microsoft Academic Search

This paper proposes a learning criterion for stochastic rules. This criterion is developed by extending Valiant's PAC (Probably Approximately Correct) learning model, which is a learning criterion for deterministic rules. Stochastic rules here refer to those which probabilistically asign a number of classes, {Y}, to each attribute vector X. The proposed criterion is based on the idea that learning stochastic

Kenji Yamanishi

1992-01-01

260

Stability of stochastic switched SIRS models  

NASA Astrophysics Data System (ADS)

Stochastic stability problems of a stochastic switched SIRS model with or without distributed time delay are considered. By utilizing the Lyapunov methods, sufficient stability conditions of the disease-free equilibrium are established. Stability conditions about the subsystem of the stochastic switched SIRS systems are also obtained.

Meng, Xiaoying; Liu, Xinzhi; Deng, Feiqi

2011-11-01

261

STOCHASTIC BURGERS EQUATION WITH RANDOM INITIAL VELOCITIES  

E-print Network

of Burgers equation under deterministic dynamics and/or additive stochastic forcing. We expect that ourSTOCHASTIC BURGERS EQUATION WITH RANDOM INITIAL VELOCITIES: A MALLIAVIN CALCULUS APPROACH Salah of the stochastic Burgers equation (SBE) on the unit interval with Dirichlet boundary conditions and anticipating

Mohammed, Salah-Eldin

262

STOCHASTIC BURGERS EQUATION + WITH RANDOM INITIAL VELOCITIES  

E-print Network

for non�linear external random forcing in the SBE (1.1). The stochastic Burgers equation has been studiedSTOCHASTIC BURGERS EQUATION + WITH RANDOM INITIAL VELOCITIES: A MALLIAVIN CALCULUS APPROACH Salah for solutions of the stochastic Burgers equation (SBE) on the unit interval with Dirichlet boundary conditions

Mohammed, Salah-Eldin

263

Conjugate Directions for Stochastic Gradient Descent  

E-print Network

of Computational Science ETH Z¨urich, Switzerland {schraudo,graepel}@inf.ethz.ch Abstract. The method of conjugate Stochastic Quadratic Optimization Deterministic bowl. The d-dimensional quadratic bowl provides us = f(w) = ¯H(w - w ). Stochastic bowl. The stochastic optimization problem analogous to the deter

Schraudolph, Nicol N.

264

Conjugate Directions for Stochastic Gradient Descent ?  

E-print Network

of Computational Science ETH Zurich, Switzerland fschraudo,graepelg@inf.ethz.ch Abstract. The method of conjugate Stochastic Quadratic Optimization Deterministic bowl. The d-dimensional quadratic bowl provides us, nonlinear problems. The gradient here is #22; g = rf(w) = #22; H(w w #3; ). Stochastic bowl. The stochastic

Schraudolph, Nicol N.

265

Multiscale Hy3S: Hybrid stochastic simulation for supercomputers  

PubMed Central

Background Stochastic simulation has become a useful tool to both study natural biological systems and design new synthetic ones. By capturing the intrinsic molecular fluctuations of "small" systems, these simulations produce a more accurate picture of single cell dynamics, including interesting phenomena missed by deterministic methods, such as noise-induced oscillations and transitions between stable states. However, the computational cost of the original stochastic simulation algorithm can be high, motivating the use of hybrid stochastic methods. Hybrid stochastic methods partition the system into multiple subsets and describe each subset as a different representation, such as a jump Markov, Poisson, continuous Markov, or deterministic process. By applying valid approximations and self-consistently merging disparate descriptions, a method can be considerably faster, while retaining accuracy. In this paper, we describe Hy3S, a collection of multiscale simulation programs. Results Building on our previous work on developing novel hybrid stochastic algorithms, we have created the Hy3S software package to enable scientists and engineers to both study and design extremely large well-mixed biological systems with many thousands of reactions and chemical species. We have added adaptive stochastic numerical integrators to permit the robust simulation of dynamically stiff biological systems. In addition, Hy3S has many useful features, including embarrassingly parallelized simulations with MPI; special discrete events, such as transcriptional and translation elongation and cell division; mid-simulation perturbations in both the number of molecules of species and reaction kinetic parameters; combinatorial variation of both initial conditions and kinetic parameters to enable sensitivity analysis; use of NetCDF optimized binary format to quickly read and write large datasets; and a simple graphical user interface, written in Matlab, to help users create biological systems and analyze data. We demonstrate the accuracy and efficiency of Hy3S with examples, including a large-scale system benchmark and a complex bistable biochemical network with positive feedback. The software itself is open-sourced under the GPL license and is modular, allowing users to modify it for their own purposes. Conclusion Hy3S is a powerful suite of simulation programs for simulating the stochastic dynamics of networks of biochemical reactions. Its first public version enables computational biologists to more efficiently investigate the dynamics of realistic biological systems. PMID:16504125

Salis, Howard; Sotiropoulos, Vassilios; Kaznessis, Yiannis N

2006-01-01

266

Assessing marginal water values in multipurpose multireservoir systems via stochastic programming  

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

267

AdViews  

NSDL National Science Digital Library

The AdViews section of the Internet Archive site contains thousands of vintage television commercials dating from the 1950s to the 1980s. These items of commercial ephemera were created or collected by the ad agency Benton & Bowles or its successor, D'Arcy Masius Benton & Bowles (DMB&B). The commercials are currently found at the John W. Hartman Center for Sales, Advertising & Marketing History in Duke University's David M. Rubenstein Rare Book & Manuscript Library. Visitors will find work created for clients such as Post, Kraft, Old Spice, Pan Am, and many others. As with other Internet Archive collections, visitors can look on the Most Downloaded Items Last Week area. Here they will most likely find advertisements for Charlie's Angels dolls, Borden's Milk, and Sugar Rice Krinkles. Visitors shouldn't miss the Subcollections area, which divides the commercials into their constituent companies, such as Beech Nut Foods, Folgers, and dozens of others.

268

Political Ad Critic  

NSDL National Science Digital Library

Brought to you by the folks at Adcritic.com, this Website features sixteen 30-second spots from the Presidential primary and general elections campaign. Political Ad Critic lists a "top ten," with Ralph Nader's hip parody ("The Truth: Priceless") of the popular MasterCard commercials awarded number one, and posts new ads from the campaign each week. Currently, there are four commercials from the Gore campaign posted here -- one of which has Gore speaking Spanish -- and six from Bush's camp, including the now-infamous "bureaucRATS" spot. (The QuickTime control bar allows users to advance frame by frame so they can judge for themselves the commercial's disputed subliminal content.) Commercials from the Libertarian party candidate Harry Browne, and primary contenders John McCain and Bill Bradley round out the Website. May the best commercial win.

269

Ad*Access  

NSDL National Science Digital Library

The Duke University Libraries has an extensive physical and online collection of advertisements that appeared in magazines and newspapers in the U.S. and Canada from 1911-1955. The Ad*Access collection focuses on advertisements in five main subject areas: Radio, Television, Transportation, Beauty and Hygiene, and World War II. Visitors should read the "About Us" section to learn about why the collection was created and its importance for research. Visitors can "browse" the collection by the aforementioned categories, product, year, and company. For example, "War Bonds" are listed under "Product", and visitors will find that the messages in war bond advertisements are quite frank, and insistent, that people should help the war effort. Visitors should check out the following ads found when browsing war bonds: "I'm Saving to go to Ag College...And Buying Bullets for Pete!", "Avenge Pearl Harbor! Buy Bonds! Give Bonds!", and "Your Bond Purchase Makes These Nazis Shiver".

270

Killing spinors and supersymmetric AdS orbifolds  

Microsoft Academic Search

We examine the behaviour of Killing spinors on AdS5 under various discrete symmetries of the spacetime. In this way we discover a number of supersymmetric orbifolds, reproducing the known ones and adding a few novel ones to the list. These orbifolds break the SO(4,2) invariance of AdS5 down to subgroups. We also make some comments on the non-compact Stiefel manifold

Bahniman Ghosh; Sunil Mukhi

1999-01-01

271

Bottlenecks in Two-Hop Ad Hoc Networks - Dividing Radio Capacity in a Smart Way  

Microsoft Academic Search

In two-hop ad hoc networks the available radio capacity tends to be equally shard among the contending stations, which may lead to bottleneck situations in case of unbalanced traffic routing. We propose a generic model for evaluating adaptive capacity sharing strategies. We use infinite-state stochastic Petri nets for modeling the system and use the logic CSRL for specifying the measures

A. Remke; B. R. Haverkort; L. Cloth; M. Mandjes; Mei van der R; R. Nunez Queija

2006-01-01

272

Optimal allocation of conservation effort among subpopulations of a threatened species: how important is patch quality?  

PubMed

Money is often a limiting factor in conservation, and attempting to conserve endangered species can be costly. Consequently, a framework for optimizing fiscally constrained conservation decisions for a single species is needed. In this paper we find the optimal budget allocation among isolated subpopulations of a threatened species to minimize local extinction probability. We solve the problem using stochastic dynamic programming, derive a useful and simple alternative guideline for allocating funds, and test its performance using forward simulation. The model considers subpopulations that persist in habitat patches of differing quality, which in our model is reflected in different relationships between money invested and extinction risk. We discover that, in most cases, subpopulations that are less efficient to manage should receive more money than those that are more efficient to manage, due to higher investment needed to reduce extinction risk. Our simple investment guideline performs almost as well as the exact optimal strategy. We illustrate our approach with a case study of the management of the Sumatran tiger, Panthera tigris sumatrae, in Kerinci Seblat National Park (KSNP), Indonesia. We find that different budgets should be allocated to the separate tiger subpopulations in KSNP. The subpopulation that is not at risk of extinction does not require any management investment. Based on the combination of risks of extinction and habitat quality, the optimal allocation for these particular tiger subpopulations is an unusual case: subpopulations that occur in higher-quality habitat (more efficient to manage) should receive more funds than the remaining subpopulation that is in lower-quality habitat. Because the yearly budget allocated to the KSNP for tiger conservation is small, to guarantee the persistence of all the subpopulations that are currently under threat we need to prioritize those that are easier to save. When allocating resources among subpopulations of a threatened species, the combined effects of differences in habitat quality, cost of action, and current subpopulation probability of extinction need to be integrated. We provide a useful guideline for allocating resources among isolated subpopulations of any threatened species. PMID:20437964

Chauvenet, Aliénor L M; Baxter, Peter W J; McDonald-Madden, Eve; Possingham, Hugh P

2010-04-01

273

Improvements in Stochastic Language Modeling  

Microsoft Academic Search

We describe two attempt to improve our stochastic language models. In the first, we identify a systematic overestimation in the traditional backoff model, and use statistical reasoning to correct it. Our modification results in up to 6% reduction in the perplexity of various tasks. Although the improvement is modest, it is achieved with hardly any increase in the complexity of

Ronald Rosenfeld; Xuedong Huang

1992-01-01

274

Stochastic-field cavitation model  

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

275

Improving strategies in stochastic games  

Microsoft Academic Search

In a zero-sum limiting average stochastic game, we evaluate a strategy T for the maximizing player, player 1, by the reward @~(T) that m guarantees to him when starting in state s. A strategy T is called non- improving if 48 (T) ~ q5~ (m(h) ) for any state s and for any finite history h, where ~(h) is the

J. Flesch; F. Thuijsman; O. J. Vrieze

1998-01-01

276

Stochastic Reinforcement Benefits Skill Acquisition  

ERIC Educational Resources Information Center

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…

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

2014-01-01

277

Stochastic Microgeometry for Displacement Mapping  

Microsoft Academic Search

Creating surfaces with intricate small-scale features (mi- crogeometry) and detail is an important task in geomet- ric modeling and computer graphics. We present a model processing method capable of producing a wide variety of complex surface features based on displacement mapping and stochastic geometry. The latter is a branch of mathe- matics that analyzes and characterizes the statistical prop- erties

Craig A. Schroeder; David E. Breen; Christopher D. Cera; William C. Regli

2005-01-01

278

SLUG: Stochastically Lighting Up Galaxies  

NASA Astrophysics Data System (ADS)

The effects of stochasticity on the luminosities of stellar populations are an often neglected but crucial element for understanding populations in the low mass or low star formation rate regime. To address this issue, we present SLUG, a new code to "Stochastically Light Up Galaxies". SLUG synthesizes stellar populations using a Monte Carlo technique that treats stochastic sampling properly including the effects of clustering, the stellar initial mass function, star formation history, stellar evolution, and cluster disruption. This code produces many useful outputs, including i) catalogs of star clusters and their properties, such as their stellar initial mass distributions and their photometric properties in a variety of filters, ii) two dimensional histograms of color-magnitude diagrams of every star in the simulation, iii) and the photometric properties of field stars and the integrated photometry of the entire simulated galaxy. After presenting the SLUG algorithm in detail, we validate the code through comparisons with starburst99 in the well-sampled regime, and with observed photometry of Milky Way clusters. Finally, we demonstrate the SLUG's capabilities by presenting outputs in the stochastic regime.

da Silva, Robert L.; Fumagalli, Michele; Krumholz, Mark

2011-06-01

279

Stochastic Robustness of Control Systems  

E-print Network

frequency #12;Classical Robust Control System Design ! PID Control Law (or compensator) ! e(t) = yC (t) " yStochastic Robustness of Control Systems Robert Stengel Princeton University May 2009 · Robustness · Design of LTI and NTV Control Systems Copyright 2009 by Robert Stengel. All rights reserved. !The problem

Stengel, Robert F.

280

Universality in Stochastic Exponential Growth  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

281

Stochastic sensors inspired by biology  

Microsoft Academic Search

Sensory systems use a variety of membrane-bound receptors, including responsive ion channels, to discriminate between a multitude of stimuli. Here we describe how engineered membrane pores can be used to make rapid and sensitive biosensors with potential applications that range from the detection of biological warfare agents to pharmaceutical screening. Notably, use of the engineered pores in stochastic sensing, a

Hagan Bayley; Paul S. Cremer

2001-01-01

282

Universality in stochastic exponential growth.  

PubMed

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. PMID:25062238

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

2014-07-11

283

Stochastic cooling: recent theoretical directions  

SciTech Connect

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.

Bisognano, J.

1983-03-01

284

Universality in stochastic exponential growth  

E-print Network

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.

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

2014-07-10

285

Stochastic sedimentation and hydrodynamic diffusion  

Microsoft Academic Search

Molecular collisions with very small particles induce Brownian motion. Consequently, such particles exhibit classical diffusion during their sedimentation. However, identical particles too large to be affected by Brownian motion also change their relative positions. This phenomenon is called hydrodynamic diffusion. Long before this term was coined, the variability of individual particle trajectories had been recognized and a stochastic model had

Elmer M. Tory

2000-01-01

286

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

ERIC Educational Resources Information Center

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…

Lyons, Lucy Eleonore; Blosser, John

2012-01-01

287

Joint Buffer & Server Allocation Van Woensel et al. Buffer and Server Allocation in General  

E-print Network

Joint Buffer & Server Allocation Van Woensel et al. Buffer and Server Allocation in General Multi Abstract -- This paper deals with the joint optimization of the number of buffers and servers, an important issue since buffers and servers represent a significant amount of investment for many companies

Cruz, Frederico

288

Criteria for Car Parking Allocation System Criteria for Car Parking Allocation System  

E-print Network

Criteria for Car Parking Allocation System Criteria for Car Parking Allocation System 2014-15 Criteria for Car Parking All #12;The issue and control of car parking permits is vested in Estates Services. The annual charges are incorporated in the application form. The car parking charges will be deducted from

Mottram, Nigel

289

Green functions in stochastic field theory  

NASA Astrophysics Data System (ADS)

Functional representations are reviewed for the generating function of Green functions of stochastic problems stated either with the use of the Fokker-Planck equation or the master equation. Both cases are treated in a unified manner based on the operator approach similar to quantum mechanics. Solution of a second-order stochastic differential equation in the framework of stochastic field theory is constructed. Ambiguities in the mathematical formulation of stochastic field theory are discussed. The Schwinger-Keldysh representation is constructed for the Green functions of the stochastic field theory which yields a functional-integral representation with local action but without the explicit functional Jacobi determinant or ghost fields.

Honkonen, Juha

2013-03-01

290

A bidding algorithm for optimized utility-based resource allocation in ad hoc networks  

E-print Network

- sically derived shadow prices. We then combine the admission control scheme with a utility-aware on-demand shortest path routing algorithm where shadow prices are used as a natural distance metric. As a baseline close to the optimum. Next we isolate the performance of price-based routing and show its advantages

291

NETCORD: a cord blood allocation network.  

PubMed

Several CB-specific prerequisites have to be taken into consideration to deal with the increasing number of stem cell transplants using multiple HLA mismatched umbilical cord blood (CB) specimens. Since CB represents a limited and expensive resource it demands an optimal allocation. Optimal CB allocation can not be optimal based solely on 'first come - first serve' basis, since frequently several CB specimens are simultaneously suitable for more than one patient. Furthermore, the immediate availability of CB gives rise to an above average proportion of urgent search requests for patients who need a transplantation urgently. Thus continuing reservation and release of a CB specimen has considerable influence on the stem cell transplant prospects of other patients. To avoid and/or solve allocation conflicts present in a much higher incidence than in the bone marrow donor setting a global co-ordinated allocation of cord blood specimens is of major advantage for these patients. Therefore, the CB allocation network NETCORD has been founded. Within NETCORD common rules for data representation and logistics were developed to make CB data comparable and interchangeable. The extended need for fast and reliable communication is met by modern communication technology based on Internet standards. PMID:9715876

Hakenberg, P; Kögler, G; Wernet, P

1998-07-01

292

Algorithmic advances in stochastic programming  

SciTech Connect

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.

Morton, D.P.

1993-07-01

293

Nonlinear realization of local symmetries of AdS space  

E-print Network

Coset methods are used to construct the action describing the dynamics associated with the spontaneous breaking of the local symmetries of AdS_{d+1} space due to the embedding of an AdS_d brane. The resulting action is an SO(2,d) invariant AdS form of the Einstein-Hilbert action, which in addition to the AdS_d gravitational vielbein, also includes a massive vector field localized on the brane. Its long wavelength dynamics is the same as a massive Abelian vector field coupled to gravity in AdS_d space.

T. E. Clark; S. T. Love; Muneto Nitta; T. ter Veldhuis

2005-06-11

294

Selection of Repetition Codes for MAC in Vehicular Ad Hoc Networks  

E-print Network

standard, 75MHz bandwidth at 5.9GHz is allocated to public and private vehicular communication applications Access Control protocol (MAC layer) in ad hoc mode for broadcast communication. The MAC protocol must traffic, transmission delay of a protocol designed for vehicular communication must be very low

Valaee, Shahrokh

295

A game theoretic analysis of distributed power control for spread spectrum ad hoc networks  

Microsoft Academic Search

We consider a distributed power control scheme in a spread spectrum (SS) wireless ad hoc network, in which each user announces a price that reflects his current interference level. Given these prices, we present an asynchronous distributed algorithm for updating power levels, and provide conditions under which this algorithm converges to an optimal power allocation. We relate this algorithm to

Jianwei Huang; Randall A. Berry; Michael L. Honig

2005-01-01

296

Biomass Resource Allocation among Competing End Uses  

SciTech Connect

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.

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

297

Task mapping for non-contiguous allocations.  

SciTech Connect

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.

Leung, Vitus Joseph; Bunde, David P. [Knox College, Galesburg, IL; Ebbers, Johnathan [Knox College, Galesburg, IL; Price, Nicholas W. [Knox College, Galesburg, IL; Swank, Matthew [Knox College, Galesburg, IL; Feer, Stefan P. [3M Health Information Systems, Inc., Wallingford, CT; Rhodes, Zachary D. [Allstate Corporation, Northbrook, IL

2013-02-01

298

Three Dimensional Origin of AdS_2 Quantum Gravity  

E-print Network

We study AdS_2 quantum gravity with emphasis on consistency with results from AdS_3. We lift AdS_2 black holes to three dimensions and map fluctuations around the solutions. Comparison with near extremal BTZ are discussed, with due emphasis on global aspects. The results confirm that parameters like central charges and conformal weights computed directly in 2D are consistent with standard results in 3D. Applying our results to the thermodynamics of near extreme Kerr black holes, we show that AdS_2 quantum gravity gives the correct central charge c=12J, and the entropy of excitations above the extremal limit is captured correctly.

Alejandra Castro; Cynthia Keeler; Finn Larsen

2010-04-05

299

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

PubMed

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

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

2014-04-01

300

AdS_{d+1} --> AdS_d  

E-print Network

Coset methods are used to construct the action describing the dynamics of the (massive) Nambu-Goldstone scalar degree of freedom associated with the spontaneous breaking of the isometry group of AdS_{d+1} space to that of an AdS_d subspace. The resulting action is an SO(2,d) invariant AdS generalization of the Nambu-Goto action. The vector field theory equivalent action is also determined.

T. E. Clark; S. T. Love; Muneto Nitta; T. ter Veldhuis

2005-01-30

301

Killing spinors and supersymmetry on AdS  

Microsoft Academic Search

In this paper we construct several supersymmetric theories on AdS5 background. We discuss the proper definition of the Killing equation for the symplectic Majorana spinors required in AdS5 supersymmetric theories. We find that the symplectic Killing spinor equation involves a matrix M in the USp(2N) indices whose role was not recognized previously. Using the correct Killing spinors we explicitly confirm

Eugene Shuster

1999-01-01

302

Minisuperspace limit of the AdS 3 WZNW model  

NASA Astrophysics Data System (ADS)

We derive the three-point function of the AdS 3 WZNW model in the minisuperspace limit by Wick rotation from the H {3/+} model. The result is expressed in terms of Clebsch-Gordan coefficients of the Lie algebra sell left( {2,mathbb{R}} right) . We also introduce a covariant basis of functions on AdS 3, which can be interpreted as bulk-boundary propagators.

Ribault, Sylvain

2010-04-01

303

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

304

Dual sourcing : with arbitrary stochastic demand and stochastic lead times.  

E-print Network

??Companies with high-performing supply chains enjoy essential competitive ad- vantages. However, supply chain management faces an environment of rising risk that endangers these competitive advantages.… (more)

Schimpel, Ulrich

2010-01-01

305

Two Virasoro symmetries in stringy warped AdS$_3$  

E-print Network

We study three-dimensional consistent truncations of type IIB supergravity which admit warped AdS$_3$ 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 AdS$_3$. Consequently, for each consistent choice of boundary conditions in AdS$_3$, we can define a consistent phase space in warped AdS$_3$ with identical conserved charges. This way, we easily obtain a Virasoro $\\times$ Virasoro asymptotic symmetry algebra in warped AdS$_3$; two different types of Virasoro $\\times$ Ka\\v{c}-Moody symmetries are also consistent alternatives. Next, we study the phase space of these theories when propagating modes are included. We show that, as long as one can define a conserved symplectic form without introducing instabilities, the Virasoro $\\times$ Virasoro asymptotic symmetries can be extended to the entire (linearized) phase space. This implies that, at least at semi-classical level, consistent theories of gravity in warped AdS$_3$ are described by a two-dimensional conformal field theory, as long as stability is not an issue.

Geoffrey Compère; Monica Guica; Maria J. Rodriguez

2014-07-29

306

Stochastic Perturbations to Dynamical Systems: A Response Theory Approach  

NASA Astrophysics Data System (ADS)

Using the formalism of the Ruelle response theory, we study how the invariant measure of an Axiom A dynamical system changes as a result of adding noise, and describe how the stochastic perturbation can be used to explore the properties of the underlying deterministic dynamics. We first find the expression for the change in the expectation value of a general observable when a white noise forcing is introduced in the system, both in the additive and in the multiplicative case. We also show that the difference between the expectation value of the power spectrum of an observable in the stochastically perturbed case and of the same observable in the unperturbed case is equal to the variance of the noise times the square of the modulus of the linear susceptibility describing the frequency-dependent response of the system to perturbations with the same spatial patterns as the considered stochastic forcing. This provides a conceptual bridge between the change in the fluctuation properties of the system due to the presence of noise and the response of the unperturbed system to deterministic forcings. Using Kramers-Kronig theory, it is then possible to derive the real and imaginary part of the susceptibility and thus deduce the Green function of the system for any desired observable. We then extend our results to rather general patterns of random forcing, from the case of several white noise forcings, to noise terms with memory, up to the case of a space-time random field. Explicit formulas are provided for each relevant case analysed. As a general result, we find, using an argument of positive-definiteness, that the power spectrum of the stochastically perturbed system is larger at all frequencies than the power spectrum of the unperturbed system. We provide an example of application of our results by considering the spatially extended chaotic Lorenz 96 model. These results clarify the property of stochastic stability of SRB measures in Axiom A flows, provide tools for analysing stochastic parameterisations and related closure ansatz to be implemented in modelling studies, and introduce new ways to study the response of a system to external perturbations. Taking into account the chaotic hypothesis, we expect that our results have practical relevance for a more general class of system than those belonging to Axiom A.

Lucarini, Valerio

2012-01-01

307

Geometric Variational Principles for Stochastic Fluid Dynamics  

E-print Network

This paper derives stochastic partial differential equations (SPDEs) for fluid dynamics from a stochastic variational principle (SVP). Both Lagrangian and Hamiltonian approaches are applied in the derivation of the stochastic dynamics. The paper proceeds by: taking variations in the SVP to derive stochastic Stratonovich fluid equations; writing their It\\^o representation; taking the expectation (or mean) of the It\\^o equations; and then investigating the properties of these stochastic fluid models in comparison with the corresponding deterministic fluid models. The circulation properties of the stochastic Stratonovich fluid equations are found to closely mimic those of the deterministic ideal fluid models. However, the It\\^o case deviates considerably because of the difference in the drift velocities. For example, the Kelvin theorem for preservation of circulation in a deterministic ideal incompressible fluid flow continues to hold in the Stratonovich case, provided the circulation loop follows the Stratonovich stochastic path. However, circulation is not preserved when the loop follows the stochastic path in the It\\^o case, because of the additional quadratic term that appears in It\\^o calculus. Motion along the stochastic Stratonovich paths also preserves the helicity of the vortex field lines in incompressible stochastic flows, but not so for stochastic It\\^o paths. The paper also derives motion equations for two examples of stochastic geophysical fluid dynamics (SGFD). The importance of Kelvin's circulation theorem in the example of Stratonovich SGFD equations is emphasised by deriving a conservation law for the potential vorticity of fluid particles moving along Stratonovich stochastic paths in both the Euler-Boussinesq and quasigeostropic approximations. However, again, the corresponding potential vorticity conservation results do not hold for It\\^o flows.

Darryl D. Holm

2014-10-30

308

Stochastic resonance in human vision and audition  

NASA Astrophysics Data System (ADS)

Stochastic resonance (SR) has been demonstrated in numerous dynamical systems, both model and real, including peripheral sensory neurons and whole animal behavior. We present the first direct evidence that SR is demonstrable also, at a level relevant to behavior in the natural environment, in human visual and auditory signal detection. Human subjects detected either square or sine wave gratings presented mixed with different amounts of pixel noise in the dark on a high-resolution computer monitor, or 3 Hz beats in a 70-Hz base tone, again mixed with different amounts of auditory noise and presented in a sound attenuation chamber while wearing industrial-quality sound-attenuating headphones. In both cases an unbiased index of performance was maximal for intermediate amounts of added noise, indicating that SR enhanced detection of subthreshold signals in both modalities. We present simple and approximate theories of performance in these experiments based on a nondynamical, or threshold, version of SR. We also discuss the possibility that SR is a general property of biological information processing that has been utilized by evolutionary processes.

Ward, Lawrence M.; Desai, Simren; Rootman, Daniel; Tata, Matthew; Moss, Frank

2001-03-01

309

Enhanced corticomuscular coherence by external stochastic noise  

PubMed Central

Noise can have beneficial effects as shown by the stochastic resonance (SR) phenomenon which is characterized by performance improvement when an optimal noise is added. Modern attempts to improve human performance utilize this phenomenon. The purpose of the present study was to investigate whether performance improvement by addition of optimum noise (ON) is related to increased cortical motor spectral power (SP) and increased corticomuscular coherence. Eight subjects performed a visuomotor task requiring to compensate with the right index finger a static force (SF) generated by a manipulandum on which Gaussian noise was applied. The finger position was displayed on-line on a monitor as a small white dot which the subjects had to maintain in the center of a green bigger circle. Electroencephalogram from the contralateral motor area, electromyogram from active muscles and finger position were recorded. The performance was measured by the mean absolute deviation (MAD) of the white dot from the zero position. ON compared to the zero noise condition induced an improvement in motor accuracy together with an enhancement of cortical motor SP and corticomuscular coherence in beta-range. These data suggest that the improved sensorimotor performance via SR is consistent with an increase in the cortical motor SP and in the corticomuscular coherence. PMID:24904365

Trenado, Carlos; Mendez-Balbuena, Ignacio; Manjarrez, Elias; Huethe, Frank; Schulte-Monting, Jurgen; Feige, Bernd; Hepp-Reymond, Marie-Claude; Kristeva, Rumyana

2014-01-01

310

Asymptotically Optimal Simulation Allocation under Dependent Sampling  

E-print Network

is to select a best design from among a finite set of competing designs that are evaluated using stochastic implies that the rate of convergence is proportional to the inverse of the square root of the number Chick and Inoue 2001ab for a Bayesian approach), but to the best of our knowledge, non

Fu, Michael

311

Allocation, incentives and distortions: the impact of EU ETS emissions allowance allocations to the electricity sector  

E-print Network

boiler 2,840 Conventional steam turbine (burning fossil fuel other than coal) 1,420 Table 1 Assumed Initial Allocation to Incumbents for Period 2005-2007 18 Comparing results for the cases where allocation of allowances... qu ili br iu m c ap ac ity (G W ) E le ct ric ity p ric e E ur o/ M W h E m is si on s M io . t C O 2 Figure 9 Long-term equilibrium effect of increasing levels of fuel-specific new entrant allocation This analysis highlights the dangers of a...

Neuhoff, Karsten; Keats, Kim; Sato, Misato

312

ADS Development in Japan  

NASA Astrophysics Data System (ADS)

Accelerator driven nuclear transmutation system has been pursued to have a clue to the solution of high-level radioactive waste management. The concept consists of super conducting linac, sub-critical reactor and the beam window. Reference model is set up to 800MW thermal power by using 1.5GeV proton beams with considerations multi-factors such as core criticality. Materials damage is simulated by high-energy particle transport codes and so on. Recent achievement on irradiation materials experiment is stated and the differences are pointed out if core burn-up is considered or not. Heat balance in tank-type ADS indicates the temperature conditions of steam generator, the beam widow and cladding materials. Lead-bismuth eutectics demonstration has been conducted. Corrosion depth rate was shown by experiments.

Kikuchi, Kenji

2010-06-01

313

Stochastic Modeling of Soil Salinity  

E-print Network

A minimalist stochastic model of primary soil salinity is proposed, in which the rate of soil salinization is determined by the balance between dry and wet salt deposition and the intermittent leaching events caused by rainfall events. The long term probability density functions of salt mass and concentration are found by reducing the coupled soil moisture and salt mass balance equation to a single stochastic differential equation driven by multiplicative Poisson noise. The novel analytical solutions provide insight on the interplay of the main soil, plant and climate parameters responsible for long-term soil salinization. In particular, they show the existence of two distinct regimes, one where the mean salt mass remains nearly constant (or decreases) with increasing rainfall frequency, and another where mean salt content increases markedly with increasing rainfall frequency. As a result, relatively small reductions of rainfall in drier climates may entail dramatic shifts in long-term soil salinization trend...

Suweis, S; Van der Zee, S E A T M; Daly, E; Maritan, A; Porporato, A; 10.1029/2010GL042495

2012-01-01

314

Stochastic stability of traffic maps  

NASA Astrophysics Data System (ADS)

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.

Blank, Michael

2012-12-01

315

Stochastic thermodynamics with information reservoirs  

NASA Astrophysics Data System (ADS)

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 .

Barato, Andre C.; Seifert, Udo

2014-10-01

316

Stochastic cooling technology at Fermilab  

NASA Astrophysics Data System (ADS)

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.

Pasquinelli, Ralph J.

2004-10-01

317

Stochastic neural nets and vision  

NASA Astrophysics Data System (ADS)

A stochastic neural net shares with the normally defined neural nets the concept that information is processed by a system consisting of a set of nodes (neurons) connected by weighted links (axons). The normal neural net takes in inputs on an initial layer of neurons which fire appropriately; a neuron of the next layer fires depending on the sum of weights of the axons leading to it from fired neurons of the first layer. The stochastic neural net differs in that the neurons are more complex and that the vision activity is a dynamic process. The first layer (viewing layer) of neurons fires stochastically based on the average brightness of the area it sees and then has a refractory period. The viewing layer looks at the image for several clock cycles. The effect is like those photo sensitive sunglasses that darken in bright light. The neurons over the bright areas are most likely in a refractory period (and this can't fire) and the neurons over the dark areas are not. Now if we move the sensing layer with respect to the image so that a portion of the neurons formerly over the dark are now over the bright, they will likely all fire on that first cycle. Thus, on that cycle, one would see a flash from that portion significantly stronger than surrounding regions. Movement the other direction would produce a patch that is darker, but this effect is not as noticeable. These effects are collected in a collection layer. This paper will discuss the use of the stochastic neural net for edge detection and segmentation of some simple images.

Fall, Thomas C.

1991-03-01

318

Stochastic train domain theory framework  

Microsoft Academic Search

The Axiomatic Safety-Critical Assessment Process (ASCAP) is illustrated as a Stochastic Train Domain Theory Framework “Plug\\u000a & Play” large-scale Monte Carlo simulation vision. The framework supports the US traditional railway system component models\\u000a as generalized operational train line taxonomy. The railway domain can be Direct Traffic Control (DTC), Centralized Traffic\\u000a Control (CTC), Cab Signaling, Positive Train Control (PTC) or a

Theo C. Giras; Zongli Lin

2004-01-01

319

Stochastic background of atmospheric cascades  

SciTech Connect

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.

Wilk, G. (Soltan Institute for Nuclear Studies, 00-681 Warsaw (Poland)); Wlodarczyk, Z. (Institute of Physics, Pedagogical University, Kielce (Poland))

1993-06-15

320

Stochastic sensors inspired by biology  

NASA Astrophysics Data System (ADS)

Sensory systems use a variety of membrane-bound receptors, including responsive ion channels, to discriminate between a multitude of stimuli. Here we describe how engineered membrane pores can be used to make rapid and sensitive biosensors with potential applications that range from the detection of biological warfare agents to pharmaceutical screening. Notably, use of the engineered pores in stochastic sensing, a single-molecule detection technology, reveals the identity of an analyte as well as its concentration.

Bayley, Hagan; Cremer, Paul S.

2001-09-01

321

Information Anatomy of Stochastic Equilibria  

E-print Network

A stochastic nonlinear dynamical system generates information, as measured by its entropy rate. Some---the ephemeral information---is dissipated and some---the bound information---is actively stored and so affects future behavior. We derive analytic expressions for the ephemeral and bound informations in the limit of small-time discretization for two classical systems that exhibit dynamical equilibria: first-order Langevin equations (i) where the drift is the gradient of a potential function and the diffusion matrix is invertible and (ii) with a linear drift term (Ornstein-Uhlenbeck) but a noninvertible diffusion matrix. In both cases, the bound information is sensitive only to the drift, while the ephemeral information is sensitive only to the diffusion matrix and not to the drift. Notably, this information anatomy changes discontinuously as any of the diffusion coefficients vanishes, indicating that it is very sensitive to the noise structure. We then calculate the information anatomy of the stochastic cusp catastrophe and of particles diffusing in a heat bath in the overdamped limit, both examples of stochastic gradient descent on a potential landscape. Finally, we use our methods to calculate and compare approximations for the so-called time-local predictive information for adaptive agents.

Sarah Marzen; James P. Crutchfield

2014-03-16

322

Information Anatomy of Stochastic Equilibria  

NASA Astrophysics Data System (ADS)

A stochastic nonlinear dynamical system generates information, as measured by its entropy rate. Some---the ephemeral information---is dissipated and some---the bound information---is actively stored and so affects future behavior. We derive analytic expressions for the ephemeral and bound informations in the limit of small-time discretization for two classical systems that exhibit dynamical equilibria: first-order Langevin equations (i) where the drift is the gradient of a potential function and the diffusion matrix is invertible and (ii) with a linear drift term (Ornstein-Uhlenbeck) but a noninvertible diffusion matrix. In both cases, the bound information is sensitive only to the drift, while the ephemeral information is sensitive only to the diffusion matrix and not to the drift. Notably, this information anatomy changes discontinuously as any of the diffusion coefficients vanishes, indicating that it is very sensitive to the noise structure. We then calculate the information anatomy of the stochastic cusp catastrophe and of particles diffusing in a heat bath in the overdamped limit, both examples of stochastic gradient descent on a potential landscape. Finally, we use our methods to calculate and compare approximations for the so-called time-local predictive information for adaptive agents.

Marzen, Sarah; Crutchfield, James

2014-08-01

323

Nonlinear and Stochastic Morphological Segregation  

E-print Network

I perform a joint counts-in-cells analysis of galaxies of different spectral types using the Las Campanas Redshift Survey (LCRS). Using a maximum-likelihood technique to fit for the relationship between the density fields of early- and late-type galaxies, I find a relative linear bias of $b=0.76\\pm 0.02$. This technique can probe the nonlinearity and stochasticity of the relationship as well. However, the degree to which nonlinear and stochastic fits improve upon the linear fit turns out to depend on the redshift range in question. In particular, there seems to be a systematic difference between the high- and low-redshift halves of the data (respectively, further than and closer than $cz\\approx 36,000$ km/s); all of the signal of stochasticity and nonlinearity comes from the low-redshift portion. Analysis of mock catalogs shows that the peculiar geometry and variable flux limits of the LCRS do not cause this effect. I speculate that the central surface brightness selection criteria of the LCRS may be responsible.

Michael Blanton

1999-08-31

324

Uncertain personal advertisement allocation for Mobile TV  

Microsoft Academic Search

In this paper we consider the problem of allocating personal TV advertisements when the viewers' viewing capacities are uncertain. We focus on the Mobile TV medium as a personal platform taking into account special constraints that are motivated by the TV medium. Since the problem is NP-Hard, we present a sequential solution procedure and propose several heuristic algorithms for solving

Ron Adany; Sarit Kraus; Fernando Ordóñez

2010-01-01

325

Register Allocation & Spilling via Graph Coloring  

Microsoft Academic Search

In a previous paper we reported the successful use of graph coloring techniques for doing global register allocation in an experimental PL\\/I optimizing compi- ler. When the compiler cannot color the register con- fliet graph with a number of colors equal to the num- ber of available machine registers, it must add code to spill and reload registers to and

Gregory J. Chaitin

1982-01-01

326

Dynamic Resources Allocation in Grid Enviroments  

Microsoft Academic Search

This paper presents DyAG, an innovative solution for dynamic allocation of resources for services workflows in Grid enviroments. The proposed solution is responsible with the efficient mapping of the services which make up a Business Process Execution Language workflow onto resources, represented by Web Services, from the Grid enviroment. The presented solution is part of a framework that aims to

Marius Ion; F. Pop; C. Dobre; V. Cristea

2009-01-01

327

Strategic Asset Allocation with Heterogeneous Beliefs  

Microsoft Academic Search

We study the presence of long term investors using different return forecasting strategies and switching them based on their past performance generates the price trends observed in financial markets. In the empirical section, we assume that investors choose how to allocate their portfoilios among four major stock indices: Dow Jones, FTSE, Nikkei and Hand Seng. The exercise shows that a

Thiago de Oliveira Souza

2010-01-01

328

The Allocation of Resources by Voting  

Microsoft Academic Search

A general theory of voting, which explains under what conditions voting will be chosen as a means for allocating resources and how the constitution that governs the voting will be structured, is presented. It is hypothesized that developers of voting organizations will structure their organizations in order to maximize the value of shares sold by minimizing the expected costs of

Yoram Barzel; Tim R. Sass

1990-01-01

329

Improving locality with dynamic memory allocation  

E-print Network

? Description . . . . . . . . . . . . . . . . 17 1. 471.omnetpp . . . . . . . . . . . . . . . . . . . . . . . 17 2. 483.xalancbmk . . . . . . . . . . . . . . . . . . . . . . 18 3. 447.dealII . . . . . . . . . . . . . . . . . . . . . . . . . 19 4. Atlas... paper, scissors: e orts to increase one hurt the others. The performance improvement obtained with our allocators is a cumulative ef- fect of their strategies on the one hand and STL automatic hints on the other hand. To study their separate contribution...

Jula, Alin Narcis

2009-05-15

330

Rumination and Impaired Resource Allocation in Depression  

PubMed Central

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

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

2010-01-01

331

RESOURCES ALLOCATION TO OPTIMIZE MINING POLLUTION CONTROL  

EPA Science Inventory

A comprehensive model for mine drainage simulation and optimization of resource allocation to control mine acid pollution in a watershed has been developed. The model is capable of: (a) Producing a time trace of acid load and flow from acid drainage sources as a function of clima...

332

Resource Allocation Patterns and Student Achievement  

ERIC Educational Resources Information Center

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…

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

2011-01-01

333

Decentralized Allocation of Tasks with Delayed Commencement  

Microsoft Academic Search

In this paper we propose an approach for flexible and decentralized task allocation based on a negotia- tion protocol and applicable in case of delayed commencement of tasks. Delayed task commencement arises when an agent has to make some eort in order to start the task, e.g. a robot first has to move towards the starting position of its task

Nelis Boucke; Danny Weyns; Tom Holvoet; Koenraad Mertens

2004-01-01

334

Telecom dogmas and spectrum allocations Andrew Odlyzko  

E-print Network

the most prominent and most disruptive new technology, and there were long debates on what the roleTelecom dogmas and spectrum allocations Andrew Odlyzko Digital Technology Center, University if it was appropriate decades ago, given the primitive wireless technologies that were available at that time

Odlyzko, Andrew M.

335

The Allocation of Resources in a University  

ERIC Educational Resources Information Center

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)

Koch, James V.

1974-01-01

336

Ground data systems resource allocation process  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

337

Characterizing Vickrey allocation rule by anonymity  

E-print Network

We consider the problem of allocating finitely many units of an indivisible good among a group of agents when each agent receives at most one unit of the good and pays a non-negative price. For example, imagine that a ...

Ashlagi, Itai

338

Optimal Allocation Of Tasks In Hypercube Computers  

NASA Technical Reports Server (NTRS)

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.

Salama, Moktar A.; Price, Camille C.

1990-01-01

339

How to Allocate Personnel Costs of Reference.  

ERIC Educational Resources Information Center

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…

Spencer, Carol

340

Dynamic stochastic optimization models for air traffic flow management  

NASA Astrophysics Data System (ADS)

This dissertation presents dynamic stochastic optimization models for Air Traffic Flow Management (ATFM) that enables decisions to adapt to new information on evolving capacities of National Airspace System (NAS) resources. Uncertainty is represented by a set of capacity scenarios, each depicting a particular time-varying capacity profile of NAS resources. We use the concept of a scenario tree in which multiple scenarios are possible initially. Scenarios are eliminated as possibilities in a succession of branching points, until the specific scenario that will be realized on a particular day is known. Thus the scenario tree branching provides updated information on evolving scenarios, and allows ATFM decisions to be re-addressed and revised. First, we propose a dynamic stochastic model for a single airport ground holding problem (SAGHP) that can be used for planning Ground Delay Programs (GDPs) when there is uncertainty about future airport arrival capacities. Ground delays of non-departed flights can be revised based on updated information from scenario tree branching. The problem is formulated so that a wide range of objective functions, including non-linear delay cost functions and functions that reflect equity concerns can be optimized. Furthermore, the model improves on existing practice by ensuring efficient use of available capacity without necessarily exempting long-haul flights. Following this, we present a methodology and optimization models that can be used for decentralized decision making by individual airlines in the GDP planning process, using the solutions from the stochastic dynamic SAGHP. Airlines are allowed to perform cancellations, and re-allocate slots to remaining flights by substitutions. We also present an optimization model that can be used by the FAA, after the airlines perform cancellation and substitutions, to re-utilize vacant arrival slots that are created due to cancellations. Finally, we present three stochastic integer programming models for managing inbound air traffic flow of an airport, when there is adverse weather impacting the arrival capacity of the airport along with its arrival fixes. These are the first models, for optimizing ATFM decisions, which address uncertainty of future capacities of multiple NAS resources.

Mukherjee, Avijit

341

Value Added in English Schools  

ERIC Educational Resources Information Center

Value-added indicators are now a central part of school accountability in England, and value-added information is routinely used in school improvement at both the national and the local levels. This article describes the value-added models that are being used in the academic year 2007-8 by schools, parents, school inspectors, and other…

Ray, Andrew; McCormack, Tanya; Evans, Helen

2009-01-01

342

Long time behaviour of a stochastic nanoparticle  

NASA Astrophysics Data System (ADS)

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).

Étoré, Pierre; Labbé, Stéphane; Lelong, Jérôme

2014-09-01

343

Size-dependent sex allocation in a simultaneous hermaphrodite parasite  

E-print Network

Size-dependent sex allocation in a simultaneous hermaphrodite parasite L. SCHAÃ? RER,* L. M, Edinburgh, Scotland, UK Introduction Models of sex allocation in hermaphrodites have classi- cally made a clear distinction between sequential and simultaneous hermaphrodites. Sequential hermaphro- dites

Schärer, Lukas

344

Quantifying the impact of customer allocations on supply chain performance  

E-print Network

This project investigates the impact that customer allocations have on key cost and service indicators at Intel Corporation. Allocations provide a method to fill orders during constrained supply, when total demand for a ...

Sheth, Neel

2012-01-01

345

30 CFR 206.459 - Allocation of washed coal.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Allocation of washed coal. 206.459 Section 206.459 Mineral Resources...REVENUE MANAGEMENT PRODUCT VALUATION Indian Coal § 206.459 Allocation of washed coal. (a) When coal is subjected to...

2010-07-01

346

30 CFR 1206.459 - Allocation of washed coal.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Allocation of washed coal. 1206.459 Section 1206.459 Mineral...Resources Revenue PRODUCT VALUATION Indian Coal § 1206.459 Allocation of washed coal. (a) When coal is subjected to...

2011-07-01

347

30 CFR 1206.459 - Allocation of washed coal.  

...2014-07-01 false Allocation of washed coal. 1206.459 Section 1206.459 Mineral...RESOURCES REVENUE PRODUCT VALUATION Indian Coal § 1206.459 Allocation of washed coal. (a) When coal is subjected to...

2014-07-01

348

30 CFR 1206.260 - Allocation of washed coal.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Allocation of washed coal. 1206.260 Section 1206.260 Mineral...RESOURCES REVENUE PRODUCT VALUATION Federal Coal § 1206.260 Allocation of washed coal. (a) When coal is subjected to...

2013-07-01

349

30 CFR 1206.260 - Allocation of washed coal.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Allocation of washed coal. 1206.260 Section 1206.260 Mineral...RESOURCES REVENUE PRODUCT VALUATION Federal Coal § 1206.260 Allocation of washed coal. (a) When coal is subjected to...

2012-07-01

350

30 CFR 1206.260 - Allocation of washed coal.  

...2014-07-01 false Allocation of washed coal. 1206.260 Section 1206.260 Mineral...RESOURCES REVENUE PRODUCT VALUATION Federal Coal § 1206.260 Allocation of washed coal. (a) When coal is subjected to...

2014-07-01

351

30 CFR 1206.459 - Allocation of washed coal.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Allocation of washed coal. 1206.459 Section 1206.459 Mineral...RESOURCES REVENUE PRODUCT VALUATION Indian Coal § 1206.459 Allocation of washed coal. (a) When coal is subjected to...

2012-07-01

352

30 CFR 1206.260 - Allocation of washed coal.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Allocation of washed coal. 1206.260 Section 1206.260 Mineral...Resources Revenue PRODUCT VALUATION Federal Coal § 1206.260 Allocation of washed coal. (a) When coal is subjected to...

2011-07-01

353

30 CFR 1206.459 - Allocation of washed coal.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Allocation of washed coal. 1206.459 Section 1206.459 Mineral...RESOURCES REVENUE PRODUCT VALUATION Indian Coal § 1206.459 Allocation of washed coal. (a) When coal is subjected to...

2013-07-01

354

30 CFR 206.260 - Allocation of washed coal.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Allocation of washed coal. 206.260 Section 206.260 Mineral Resources...REVENUE MANAGEMENT PRODUCT VALUATION Federal Coal § 206.260 Allocation of washed coal. (a) When coal is subjected to...

2010-07-01

355

7 CFR 1493.4 - Criteria for country allocations.  

Code of Federal Regulations, 2011 CFR

...for country allocations. The criteria considered by CCC in reviewing proposals for country allocations under the GSM-102 or GSM-103 programs, will include, but not be limited to, the following: (a) Potential benefits that the...

2011-01-01

356

7 CFR 1493.4 - Criteria for country allocations.  

Code of Federal Regulations, 2010 CFR

...for country allocations. The criteria considered by CCC in reviewing proposals for country allocations under the GSM-102 or GSM-103 programs, will include, but not be limited to, the following: (a) Potential benefits that the...

2010-01-01

357

12 CFR 347.303 - Allocated transfer risk reserve.  

Code of Federal Regulations, 2010 CFR

...Allocated transfer risk reserve. 347.303 Section... Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION...STATEMENTS OF GENERAL POLICY INTERNATIONAL BANKING...Allocated transfer risk reserve. (a) Establishment...least annually, the federal banking agencies...

2010-01-01

358

11 CFR 9004.7 - Allocation of travel expenditures.  

...2014-01-01 false Allocation of travel expenditures. 9004.7 Section 9004...PAYMENTS § 9004.7 Allocation of travel expenditures. (a) Notwithstanding...provisions of 11 CFR 106.3, expenditures for travel relating to a Presidential or...

2014-01-01

359

14 CFR 93.215 - Initial allocation of slots.  

Code of Federal Regulations, 2013 CFR

...TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93.215 Initial allocation of slots. (a) Each air carrier and commuter operator...

2013-01-01

360

14 CFR 93.215 - Initial allocation of slots.  

Code of Federal Regulations, 2012 CFR

...TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93.215 Initial allocation of slots. (a) Each air carrier and commuter operator...

2012-01-01

361

14 CFR 93.215 - Initial allocation of slots.  

...TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93.215 Initial allocation of slots. (a) Each air carrier and commuter operator...

2014-01-01

362

A Distributed Tasks Allocation Scheme in Multi-UAV Context  

Microsoft Academic Search

This paper deals with the task allocation problem in multi-robot systems. We propose a completely distributed architecture, where robots dynamically allocate their tasks while they are building their plans. We first focus on the problem of simple \\

Thomas Lemaire; Rachid Alami; Simon Lacroix

2004-01-01

363

34 CFR 300.807 - Allocations to States.  

...REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR THE EDUCATION OF CHILDREN WITH DISABILITIES Preschool Grants for Children with Disabilities § 300.807 Allocations to States. The Secretary allocates the amount...

2014-07-01

364

34 CFR 300.807 - Allocations to States.  

Code of Federal Regulations, 2012 CFR

...REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR THE EDUCATION OF CHILDREN WITH DISABILITIES Preschool Grants for Children with Disabilities § 300.807 Allocations to States. The Secretary allocates the amount...

2012-07-01

365

34 CFR 300.807 - Allocations to States.  

Code of Federal Regulations, 2010 CFR

...REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR THE EDUCATION OF CHILDREN WITH DISABILITIES Preschool Grants for Children with Disabilities § 300.807 Allocations to States. The Secretary allocates the amount...

2010-07-01

366

34 CFR 300.807 - Allocations to States.  

Code of Federal Regulations, 2011 CFR

...REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR THE EDUCATION OF CHILDREN WITH DISABILITIES Preschool Grants for Children with Disabilities § 300.807 Allocations to States. The Secretary allocates the amount...

2011-07-01

367

34 CFR 300.807 - Allocations to States.  

Code of Federal Regulations, 2013 CFR

...REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION ASSISTANCE TO STATES FOR THE EDUCATION OF CHILDREN WITH DISABILITIES Preschool Grants for Children with Disabilities § 300.807 Allocations to States. The Secretary allocates the amount...

2013-07-01

368

24 CFR 982.101 - Allocation of funding.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Allocation of funding. 982.101 Section 982.101 Housing and...BASED ASSISTANCE: HOUSING CHOICE VOUCHER PROGRAM Funding and PHA Application for Funding § 982.101 Allocation of funding....

2010-04-01

369

24 CFR 982.101 - Allocation of funding.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Allocation of funding. 982.101 Section 982.101 Housing and...BASED ASSISTANCE: HOUSING CHOICE VOUCHER PROGRAM Funding and PHA Application for Funding § 982.101 Allocation of funding....

2011-04-01

370

24 CFR 982.101 - Allocation of funding.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Allocation of funding. 982.101 Section 982.101 Housing and...BASED ASSISTANCE: HOUSING CHOICE VOUCHER PROGRAM Funding and PHA Application for Funding § 982.101 Allocation of funding....

2012-04-01

371

1985 NAPAP EMISSIONS INVENTORY: DEVELOPMENT OF SPECIES ALLOCATION FACTORS  

EPA Science Inventory

The report describes the methodologies and data bases used to develop species allocation factors and data processing software used to develop the 1985 National Acid Precipitation Assessment Program (NAPAP) Modelers' Emissions Inventory (Version 2). Species allocation factors were...

372

7 CFR 3430.311 - Allocation of research funds.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Allocation of research funds. 3430.311 Section 3430.311...ADMINISTRATIVE PROVISIONS Agriculture and Food Research Initiative § 3430.311 Allocation of research funds. (a) Fundamental...

2013-01-01

373

7 CFR 3430.311 - Allocation of research funds.  

... 2014-01-01 false Allocation of research funds. 3430.311 Section 3430.311...ADMINISTRATIVE PROVISIONS Agriculture and Food Research Initiative § 3430.311 Allocation of research funds. (a) Fundamental...

2014-01-01

374

7 CFR 3430.311 - Allocation of research funds.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Allocation of research funds. 3430.311 Section 3430.311...ADMINISTRATIVE PROVISIONS Agriculture and Food Research Initiative § 3430.311 Allocation of research funds. (a) Fundamental...

2012-01-01

375

45 CFR 402.31 - Determination of allocations.  

Code of Federal Regulations, 2010 CFR

... OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES STATE LEGALIZATION IMPACT ASSISTANCE GRANTS State Allocations § 402.31 Determination of allocations. (a)...

2010-10-01

376

45 CFR 402.34 - Allocation of unexpended funds.  

Code of Federal Regulations, 2011 CFR

... OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES STATE LEGALIZATION IMPACT ASSISTANCE GRANTS State Allocations § 402.34 Allocation of unexpended funds. (a)...

2011-10-01

377

45 CFR 402.34 - Allocation of unexpended funds.  

Code of Federal Regulations, 2010 CFR

... OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES STATE LEGALIZATION IMPACT ASSISTANCE GRANTS State Allocations § 402.34 Allocation of unexpended funds. (a)...

2010-10-01

378

45 CFR 402.31 - Determination of allocations.  

Code of Federal Regulations, 2011 CFR

... OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES STATE LEGALIZATION IMPACT ASSISTANCE GRANTS State Allocations § 402.31 Determination of allocations. (a)...

2011-10-01

379

Essays on the real and financial allocation of capital  

E-print Network

This dissertation consists of three papers studying how firms allocate real and financial capital, and how taxes, the labor market and asymmetric information affect these allocation decisions. The first paper studies the ...

Ramírez Verdugo, Arturo

2006-01-01

380

10 CFR 490.703 - Biodiesel fuel use credit allocation.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Biodiesel fuel use credit allocation. 490.703... ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.703 Biodiesel fuel use credit allocation. (a)...

2010-01-01

381

Recipient allocation preferences and organizational choices: a fit perspective  

E-print Network

, equality norm and need norm) and taking the perspective of the recipient of an allocation, a model that predicts the antecedents of norm preference and consequences of using different allocation norms by the organization is presented and tested with a...

Gogus, Celile Itir

2007-04-25

382

14 CFR 93.215 - Initial allocation of slots.  

Code of Federal Regulations, 2010 CFR

...TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93.215 Initial allocation of slots. (a) Each air carrier and commuter operator...

2010-01-01

383

14 CFR 93.215 - Initial allocation of slots.  

Code of Federal Regulations, 2011 CFR

...TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Allocation of Commuter and Air Carrier IFR Operations at High Density Traffic Airports § 93.215 Initial allocation of slots. (a) Each air carrier and commuter operator...

2011-01-01

384

Stochastic Linear Quadratic Optimal Control Problems  

SciTech Connect

This paper is concerned with the stochastic linear quadratic optimal control problem (LQ problem, for short) for which the coefficients are allowed to be random and the cost functional is allowed to have a negative weight on the square of the control variable. Some intrinsic relations among the LQ problem, the stochastic maximum principle, and the (linear) forward-backward stochastic differential equations are established. Some results involving Riccati equation are discussed as well.

Chen, S. [Department of Mathematics, Zhejiang University, Hangzhou 310027 (China); Yong, J. [Laboratory of Mathematics for Nonlinear Sciences, Department of Mathematics, and Institute of Mathematical Finance, Fudan University, Shanghai 200433 (China)

2001-07-01

385

Learning to imitate stochastic time series in a compositional way by chaos  

E-print Network

This study shows that a mixture of RNN experts model can acquire the ability to generate sequences combining multiple primitive patterns by means of self-organizing chaos. By training of the model, each expert learns a primitive sequence pattern, and a gating network learns to imitate stochastic switching of the multiple primitives via a chaotic dynamics, utilizing a sensitive dependence on initial conditions. As a demonstration, we present a numerical simulation in which the model learns Markov chain switching among some Lissajous curves by a chaotic dynamics. Our analysis shows that by using a sufficient amount of training data, balanced with the network memory capacity, it is possible to satisfy the conditions for embedding the target stochastic sequences into a chaotic dynamical system. It is also shown that reconstruction of a stochastic time series by a chaotic model can be stabilized by adding a negligible amount of noise to the dynamics of the model.

Jun Namikawa; Jun Tani

2008-05-13

386

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

NASA Astrophysics Data System (ADS)

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.

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

2012-01-01

387

Classification of Boundary Gravitons in AdS$_3$ Gravity  

E-print Network

We revisit the description of the space of asymptotically AdS3 solutions of pure gravity in three dimensions with a negative cosmological constant as a collection of coadjoint orbits of the Virasoro group. Each orbit corresponds to a set of metrics related by diffeomorphisms which do not approach the identity fast enough at the boundary. Orbits contain more than a single element and this fact manifests the global degrees of freedom of AdS3 gravity, being each element of an orbit what we call boundary graviton. We show how this setup allows to learn features about the classical phase space that otherwise would be quite difficult. Most important are the proof of energy bounds and the characterization of boundary gravitons unrelated to BTZs and AdS3. In addition, it makes manifest the underlying mathematical structure of the space of solutions close to infinity. Notably, because of the existence of a symplectic form in each orbit, being this related with the usual Dirac bracket of the asymptotic charges, this approach is a natural starting point for the quantization of different sectors of AdS3 gravity. We finally discuss previous attempts to quantize coadjoint orbits of the Virasoro group and how this is relevant for the formulation of AdS3 quantum gravity.

Alan Garbarz; Mauricio Leston

2014-03-13

388

Two Virasoro symmetries in stringy warped AdS$_3$  

E-print Network

We study three-dimensional consistent truncations of type IIB supergravity which admit warped AdS$_3$ 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 AdS$_3$. Consequently, for each consistent choice of boundary conditions in AdS$_3$, we can define a consistent phase space in warped AdS$_3$ with identical conserved charges. This way, we easily obtain a Virasoro $\\times$ Virasoro asymptotic symmetry algebra in warped AdS$_3$; two different types of Virasoro $\\times$ Ka\\v{c}-Moody symmetries are also consistent alternatives. Next, we study the phase space of these theories when propagating modes are included. We show that, as long as one can define a conserved symplectic form without introducing instabilities, the Virasoro $\\times$ Virasoro asymptotic symmetries can be extended to the entire (linearized) phase space. This implies t...

Compère, Geoffrey; Rodriguez, Maria J

2014-01-01

389

A stochastic tractography system and applications  

E-print Network

Neuroscientists hypothesize that the pathologies of some neurological diseases are associated with neuroanatomical abnormalities. Diffusion Tensor Imaging (DTI) and stochastic tractography allow us to investigate white ...

Ngo, Tri M. (Tri Minh)

2007-01-01

390

Neuronal Growth: A Bistable Stochastic Process  

NASA Astrophysics Data System (ADS)

The fundamentally stochastic nature of neuronal growth has hardly been addressed in neuroscience. We report on the stochastic fluctuations of a neuronal growth cone’s leading edge movement, the basic step in neuronal growth. Describing the edge movement as a stochastic bistable process leads to an isotropic noise parameter that is successfully used to test the model. An analysis of growth cone motility confirms the model, and predicts that linear changes of the bistable potential, as known from stochastic filtering, result in directed growth cone translocation.

Betz, Timo; Lim, Daryl; Käs, Josef A.

2006-03-01

391

The allocation of ecosystem net primary productivity in tropical forests.  

PubMed

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 (r(2) = 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

Malhi, Yadvinder; Doughty, Christopher; Galbraith, David

2011-11-27

392

The allocation of ecosystem net primary productivity in tropical forests  

PubMed Central

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

Malhi, Yadvinder; Doughty, Christopher; Galbraith, David

2011-01-01

393

On Bandwidth Allocation for Data Dissemination in Cellular Mobile Networks  

Microsoft Academic Search

Wireless bandwidth is a scarce resource in a cellular mobile network. As such, it is important to effectively allocate bandwidth to each cell such that the overall system performance is optimized. Channel allocation strategies have been extensively studied for voice communications in cellular networks. However, for data dissemination applications, studies on bandwidth allocation have thus far been limited to a

Jianliang Xu; Dik L. Lee; Bo Li

2003-01-01

394

Queuing analysis of dynamic resource allocation for virtual routers  

E-print Network

Queuing analysis of dynamic resource allocation for virtual routers M. Said Seddiki , Bilel Nefzi routers in order to allow an adaptive change in the resource allocation. In this paper, we focus on the router data plane virtualization and we explore this issue by presenting a new dynamic allocation

Paris-Sud XI, Université de

395

48 CFR 1631.203-70 - Allocation techniques.  

Code of Federal Regulations, 2010 CFR

...method . The preferred allocation technique is one that shows the consumption of resources in performance of...cost grouping. This allocation technique should...determine, the basis for allocation may be a measure of...measure for the use of resources and is a...

2010-10-01

396

7 CFR 1466.5 - National allocation and management.  

Code of Federal Regulations, 2010 CFR

...Use an EQIP fund allocation formula that reflects...available natural resource and resource...information about resource concerns and program...data used in the allocation formula will be...implementation such as resource priorities, eligible...schedules, fund allocation, and program...

2010-01-01

397

15 CFR 923.124 - Allocation of section 309 funds.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Allocation of section 309 funds... OCEAN AND COASTAL RESOURCE MANAGEMENT COASTAL...Program § 923.124 Allocation of section 309 funds...than the State's base allocation. Each State's weighted...of improved coastal resource management;...

2010-01-01

398

PETROLEUM ALLOCATION AT PETROBRAS: MATHEMATICAL MODEL AND A SOLUTION  

E-print Network

PETROLEUM ALLOCATION AT PETROBRAS: MATHEMATICAL MODEL AND A SOLUTION ALGORITHM Roger Rocha1 Petroleum Allocation is an important link for the integration of Petroleum Supply Chain at PETROBRAS. In this work we describe how mathematical programming is being used to solve the Petroleum Allocation Problem

Grossmann, Ignacio E.

399

Choice of Allocation Granularity in Multipath Source Routing Schemes  

Microsoft Academic Search

Multipath source routing schemes can be distinguished by their choice of allocation granularity. The schemes proposed in the literature advocate a per-connection allocation wherein all the packets of a connection are constrained to follow the same path. The authors believe that a smaller allocation granularity permits a finer control to be exerted and would result in improved performance, especially in

Ram Krishnan; John A. Silvester

1993-01-01

400

A Multi-agent Approach for Semantic Resource Allocation  

Microsoft Academic Search

This paper presents a new approach of the Semantically Enhanced Resource Allocation (SERA) distributed as a multi-agent system. It presents a distributed resource allocation process which combines the benefits of semantic web for making easier the integration between multiple resource providers in the Cloud and agent technologies for coordinating and adapting the execution accross the different providers. The allocation process

Jorge Ejarque; Rosa M. Badia

2010-01-01

401

Quality and Speed in Linear-scan Register Allocation  

Microsoft Academic Search

A algorithm directs the global allocation of register candidates to registers based on a simple linear sweep over the program being compiled. This approach to register allocation makes sense for systems, such as those for dynamic compilation, where compilation speed is important. In contrast, most commercial and research optimizing compilers rely on a graph-coloring approach to global register allocation. In

Omri Traub; Glenn H. Holloway; Michael D. Smith

1998-01-01

402

Playing games against nature: optimal policies for renewable resource allocation  

E-print Network

Playing games against nature: optimal policies for renewable resource allocation Stefano Ermon- cision processes that arise as a natural model for many renewable resource allocation problems. Upon for the allocation of renewable resources. A key and unique aspect of such a resource type is the fact that

Keinan, Alon

403

Sustainable Groundwater Allocation in the Great Lakes Basin  

Microsoft Academic Search

Outdated groundwater allocation policies have resulted in unrestrained abstraction of groundwater in the Great Lakes Basin. Continuing on this course will lead to more frequent conflicts and further degradation of the Basin's ecosystem. Alternative approaches must focus on achieving sustainable groundwater allocation. The authors present two alternative institutions, local collaborative planning for groundwater allocation, and a regional watershed board. Collaborative

Timothy J. Morris; Satya P. Mohapatra; Anne Mitchell

2006-01-01

404

Reward Allocation and Academic versus Social Orientation toward School.  

ERIC Educational Resources Information Center

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)…

Peterson, Candida C.; Peterson, James L.

1978-01-01

405

MA 747, Spring 2012 Probability and Stochastic Process II  

E-print Network

MA 747, Spring 2012 Probability and Stochastic Process II Lecture Notes and Reference book theory needed for advanced applications in stochastic processes. It provides the basic probability theory chains, martingales, stopping times, Poisson jump Process, Brownian motion and Stochastic integral

Ito, Kazufumi

406

Wilson lines for AdS_5 black strings  

E-print Network

We describe a simple method of extending AdS_5 black string solutions of 5d gauged supergravity in a supersymmetric way by adding Wilson lines along the string direction. Due to the specific form of 5d supergravity that features Chern-Simons terms, the existence of magnetic charges automatically generates conserved electric charges upon the addition of such Wilson lines in a 5d analogue of the Witten effect. Therefore we find a rather generic, model-independent way of adding electric charges to already existing solutions with no backreaction from the geometry or breaking of any symmetry. We use this method to explicitly write down a more general version of the Benini-Bobev black strings and comment on the implications for the dual field theory and the similarities with generalizations of the Cacciatori-Klemm black holes in AdS_4.

Hristov, Kiril

2014-01-01

407

On the Geometric Properties of AdS Instantons  

E-print Network

According to the positive energy conjecture of Horowitz and Myers, there is a specific supergravity solution, AdS soliton, which has minimum energy among all asymptotically locally AdS solutions with the same boundary conditions. Related to the issue of semiclassical stability of AdS soliton in the context of pure gravity with a negative cosmological constant, physical boundary conditions are determined for an instanton solution which would be responsible for vacuum decay by barrier penetration. Certain geometric properties of instantons are studied, using Hermitian differential operators. On a $d$-dimensional instanton, it is shown that there are $d-2$ harmonic functions. A class of instanton solutions, obeying more restrictive boundary conditions, is proved to have $d-1$ Killing vectors which also commute. All but one of the Killing vectors are duals of harmonic one-forms, which are gradients of harmonic functions, and do not have any fixed points.

Ali Kaya

1999-05-31

408

Ethics of allocating intensive care unit resources.  

PubMed

ICU clinicians commonly make decisions that allocate resources. Because of the high cost of ICU care, these practitioners can expect to be involved in the growing dilemma of trying to meet increasing demand for healthcare services within financial constraints. In order to participate meaningfully in a societal discussion over fairness in allocating scare and expensive resources, ICU practitioners should have more than a superficial knowledge of the principles of distributive justice. Distributive justice refers to fairness in the distribution of limited resources and benefits. Fairness refers to giving equal treatment to all those who are the same with regard to certain morally significant characteristics and treating in a different manner those who are not the same. Although theoretical issues remain unresolved as to which characteristics should be most significant, the United States has a strong cultural value that regards individuals as inherently valuable and having equal social worth. From this, it is likely that only an egalitarian approach to allocation of lifesaving healthcare resources will be acceptable. Studies of how ICU resources have been allocated during times of scarcity indicates that, in general, when beds are scarce, the average severity of illness of those admitted to the ICU increases. However, in some hospitals, political and economic factors appear to play important roles in determining who has access to scarce ICU beds. Of great concern is documentation of a widespread pattern in which fewer hospital resources, including ICU resources, are provided to seriously ill patients of minority status or with low levels of insurance reimbursement. How society's values get translated into allocation decisions is another unresolved issue. One recent example of how this occurred is the Oregon Medicaid Plan. This plan extended Medicaid coverage to additional people in poverty, despite the same amount of state and federal funds. This was accomplished by not reimbursing what were regarded as marginally beneficial services on the basis of medical and community input. Portents of how society might be involved in the future of health care are illustrated by the argument that society should limit access to all therapies except palliative care solely on the basis of advanced age. Until an open consensus develops in U.S. society about how to allocate scarce healthcare resources, the delivery of ICU care will continue to be at risk of covert, de facto rationing based on ability to pay, race, or other nonmedical personal characteristics. PMID:9017677

Lanken, P N; Terry, P B; Osborne, M L

1997-02-01

409

Brane Embeddings in AdS4 × { {CP}}3  

NASA Astrophysics Data System (ADS)

We construct D-brane embeddings in AdS4 × { {CP}}3 by studying the consistency conditions following from the pull back of target space equations of motion. We explicitly discuss the supersymmetry preserved by these embeddings by analyzing the compatibility of kappa symmetry projections with the target space Killing spinors in each case. The embeddings correspond to AdS/dCFT dualities involving ABJM theories with a defect. We also comment on the defect CFT.

Chandrasekhar, B.; Panda, Binata

410

Comments on String Theory on $AdS_3$  

Microsoft Academic Search

We study string propagation on $AdS_3$ times a compact space from an ``old fashioned'' worldsheet point of view of perturbative string theory. We derive the spacetime CFT and its Virasoro and current algebras, thus establishing the conjectured $AdS$\\/CFT correspondence for this case in the full string theory. Our results have implications for the extreme IR limit of the $D1-D5$ system,

Amit Giveon; David Kutasov; Nathan Seiberg

1998-01-01

411

On the Eikonal Approximation in AdS Space  

E-print Network

We explore the eikonal approximation to graviton exchange in AdS_5 space, as relevant to scattering in gauge theories. We restrict ourselves to the regime where conformal invariance of the dual gauge theory holds, and to large 't Hooft coupling where the computation involves pure gravity. We give a heuristic argument, a direct loop computation, and a shock wave derivation. The scalar propagator in AdS_3 plays a key role, indicating that even at strong coupling, two-dimensional conformal invariance controls high-energy four-dimensional gauge-theory scattering.

Richard C. Brower; Matthew J. Strassler; Chung-I Tan

2007-07-17

412

Mixed-symmetry fields in AdS(5), conformal fields, and AdS/CFT  

E-print Network

Mixed-symmetry arbitrary spin massive, massless, and self-dual massive fields in AdS(5) are studied. Light-cone gauge actions for such fields leading to decoupled equations of motion are constructed. Light-cone gauge formulation of mixed-symmetry anomalous conformal currents and shadows in 4d flat space is also developed. AdS/CFT correspondence for normalizable and non-normalizable modes of mixed-symmetry AdS fields and the respective boundary mixed-symmetry anomalous conformal currents and shadows is studied. We demonstrate that the light-cone gauge action for massive mixed-symmetry AdS field evaluated on solution of the Dirichlet problem amounts to the light-cone gauge 2-point vertex of mixed-symmetry anomalous shadow. Also we show that UV divergence of the action for mixed-symmetry massive AdS field with some particular value of mass parameter evaluated on the Dirichlet problem amounts to the action of long mixed-symmetry conformal field, while UV divergence of the action for mixed-symmetry massless AdS field evaluated on the Dirichlet problem amounts to the action of short mixed-symmetry conformal field. We speculate on string theory interpretation of a model which involves short low-spin conformal fields and long higher-spin conformal fields.

R. R. Metsaev

2014-10-27

413

MCdevelop - a universal framework for Stochastic Simulations  

NASA Astrophysics Data System (ADS)

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.

Slawinska, M.; Jadach, S.

2011-03-01

414

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

NASA Astrophysics Data System (ADS)

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].

Tanimoto, Jun

2014-08-01

415

Stochastic Calculus of Wrapped Compartments  

E-print Network

The Calculus of Wrapped Compartments (CWC) is a variant of the Calculus of Looping Sequences (CLS). While keeping the same expressiveness, CWC strongly simplifies the development of automatic tools for the analysis of biological systems. The main simplification consists in the removal of the sequencing operator, thus lightening the formal treatment of the patterns to be matched in a term (whose complexity in CLS is strongly affected by the variables matching in the sequences). We define a stochastic semantics for this new calculus. As an application we model the interaction between macrophages and apoptotic neutrophils and a mechanism of gene regulation in E.Coli.

Coppo, Mario; Drocco, Maurizio; Grassi, Elena; Troina, Angelo; 10.4204/EPTCS.28.6

2010-01-01

416

Stochastic Control of Metabolic Pathways  

E-print Network

We study the effect of extrinsic noise in metabolic networks. We introduce external random fluctuations at the kinetic level, and show how these lead to a stochastic generalization of standard Metabolic Control Analysis. While Summation and Connectivity Theorems hold true in presence of extrinsic noise, control coefficients incorporate its effect through an explicit dependency on the noise intensity. New elasticities and response coefficients are also defined. Accordingly, the concept of control by noise is introduced as a way of tuning the systemic behaviour of metabolisms. We argue that this framework holds for intrinsic noise too, when time-scale separation is present in the system.

Andrea Rocco

2009-06-01

417

Stochastic solution to quantum dynamics  

NASA Technical Reports Server (NTRS)

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.

John, Sarah; Wilson, John W.

1994-01-01

418

Stochastic excitation of stellar oscillations  

E-print Network

Excitation of solar oscillations is attribued to turbulent motions in the solar convective zone. It is also currently believed that oscillations of low massive stars (M <2 Mo) - which possess an upper convective zone - are stochastically excited by turbulent convection in their outer layers. A recent theoretical work (Samadi & Goupil, 2001 ; Samadi et al, 2001) supplements and reinforces this theory. This allows the use of any available model of turbulence and emphasizes some recent unsolved problems which are brought up by these new theoretical developments.

Reza Samadi

2001-08-22

419

Stochastic quantization for complex actions  

SciTech Connect

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.

Menezes, G.; Svaiter, N. F. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rua Dr. Xavier Sigaud 150, Rio de Janeiro 22290-180 (Brazil)

2008-10-15

420

Stochastic Models of Human Errors  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

421

Linking Network Structure and Diffusion Through Stochastic Dominance  

E-print Network

Recent research identifies stochastic dominance as critical for understanding the relationship between network structure and diffusion. This paper introduces the concept of stochastic dominance, explains the theory linking ...

Lamberson, P.J.

2009-09-28

422

Personal advertisement allocation for mobile TV  

Microsoft Academic Search

Personal advertisements are the next-generation in the world of advertisement. In this article we consider the personal advertisement allocation problem with constraints that are motivated by the TV and Mobile advertisement worlds. This problem is a version of the Generalized Multi-Assignment Problem, defined as an extension of GAP with assignment restrictions and all-or-nothing constraints. We present an Integer Programming (IP)

Ron Adany; Sarit Kraus; Fernando Ordóñez

2009-01-01

423

DYNAMIC SPECTRUM ALLOCATION (DSA) AND RECONFIGURABILITY  

Microsoft Academic Search

In the context of the European research project OverDRiVE (Spectrum Efficient Uni- and Multicast Services Over Dynamic Radio Networks in Vehicular Environments), this paper presents the flexible spectrum management strategy (the dynamic spectrum allocation concept) developed in the project, and discusses OverDRiVE's approach to identify and formalise the impact of DSA on both reconfigurability and SDR equipment, capturing the reconfigurable

David Grandblaise; Didier Bourse; Klaus Moessner; Paul Leaves

2002-01-01

424

Spatial allocation of forest recreation value  

Microsoft Academic Search

Non-market valuation methods and geographic information systems are useful planning and management tools for public land managers. Recent attention has been given to investigation and demonstration of methods for combining these tools to provide spatially-explicit representations of non-market value. Most of these efforts have focused on spatial allocation of ecosystem service values based on land cover types, but recreation value

Kenneth A. Baerenklau; Armando González-Cabán; Catrina Paez; Edgar Chavez

2010-01-01

425

Improving Register Allocation for Subscripted Variables  

Microsoft Academic Search

Most conventional compilers fail to allocate array el- ements to registers because standard data-flow anal- ysis treats arrays like scalars, making it impossible to analyze the definitions and uses of individual array elements. This deficiency is particularly troublesome for floating-point registers, which are most often used as temporary repositories for subscripted variables. In this paper, we present a source-to-source trans-

David Callahan; Steve Carr; Ken Kennedy

1990-01-01

426

Integrated Cooperative Framework for Project Resources Allocation  

Microsoft Academic Search

\\u000a The present paper presents a generic, flexible and robust framework for decision support in cooperative systems in charge\\u000a with human resources allocation for various project tasks. Considering a knowledge database where people and projects are\\u000a characterized through the task and competences binomial, the particularity of this frameworks consists in integrating inside\\u000a the cooperative systems the benefits of complex user modeling

Mihaela Brut; Jean-Luc Soubie; Florence Sèdes

427

Legal briefing: organ donation and allocation.  

PubMed

This issue's "Legal Briefing" column covers legal developments pertaining to organ donation and allocation. This topic has been the subject of recent articles in JCE. Organ donation and allocation have also recently been the subjects of significant public policy attention. In the past several months, legislatures and regulatory agencies across the United States and across the world have changed, or considered changing, the methods for procuring and distributing human organs for transplantation. Currently, in the U.S., more than 100,000 persons are waiting for organ transplantation. In China, more than 1.5 million people are waiting. Given the chronic shortage of available organs (especially kidneys and livers) relative to demand, the primary focus of most legal developments has been on increasing the rate of donation. These and related developments are usefully divided into the following 12 topical categories: 1. Revised Uniform Anatomical Gift Act. 2. Presumed Consent and Opt-Out. 3. Mandated Choice. 4. Donation after Cardiac Death. 5. Payment and Compensation. 6. Donation by Prisoners. 7. Donor Registries. 8. Public Education. 9. Other Procurement Initiatives. 10. Lawsuits and Liability. 11. Trafficking and Tourism. 12. Allocation and Distribution. PMID:21089996

Pope, Thaddeus Mason

2010-01-01

428

Adapting water allocation management to drought scenarios  

NASA Astrophysics Data System (ADS)

Climate change dynamics have significant consequences on water resources on a watershed scale. With water becoming scarcer and susceptible to variation, the planning and reallocation decisions in watershed management need to be reviewed. This research focuses on an in-depth understanding of the current allocation balance of water resources among competitors, placed along the course of the Adda River. In particular, during the summer period, the demand for water dramatically increases. This is due to the increase in irrigation activities in the lower part of the basin and to the highest peaks of tourist inflow, in the Como Lake and Valtellina areas. Moreover, during these months, the hydroelectric reservoirs in the upper part of the Adda River basin (the Valtellina) retain most of the volume of water coming from the snow and glacier melt. The existing allocation problem among these different competing users is exacerbated by the decreasing water supplies. The summer of 2003 testified the rise in a number of allocation problems and situations of water scarcity that brought about environmental and economical consequences. The RICLIC project is committed to the understanding of water dynamics on a regional scale, to quantify the volumes involved and offer local communities an instrument to improve a sustainable water management system, within uncertain climate change scenarios.

Giacomelli, P.; Rossetti, A.; Brambilla, M.

2008-04-01

429

Attention allocation patterns in naturalistic driving.  

PubMed

The key to safe driving is the adequate distribution of the driver's attention to the forward area and to other non-forward focal points. However, thus far, current methods are not able to well quantify the entire process of a driver's attention allocation. Therefore, this study proposed a novel concept of renewal cycles for representing and analyzing driver attention allocation. Using the 100-car naturalistic glance data, this study found that 90.74% of drivers' attention allocations were 2-glance renewal cycles. The findings suggest that the sample drivers usually separated their lapses of attention from the forward direction into several sequences by directing their vision back to the forward direction after each visual shift away from it. In addition, although a markedly smaller number of cycles were more than 3-glances (2.09% renewal cycles), drivers were certainly less aware of the frontal area and at a higher risk of having an accident during such cycles. This finding might have striking implications for accident prevention. This area of study deserves further attention. Among the generated renewal cycles, lots of them repeated frequently, especially cycles related to invehicle distractions. To analyze the different characteristics among various attributes, distribution of the common renewal cycles under different conditions was examined. As expected, drivers displayed different renewal cycles under various road conditions and with various driver intentions. Although these sample drivers were not representative, the preliminary research results were promising and fruitful for potential applications, particularly educating novice drivers. PMID:23743253

Wong, Jinn-Tsai; Huang, Shih-Hsuan

2013-09-01

430

Stochastic Flash Analog-to-Digital Conversion  

Microsoft Academic Search

A stochastic flash analog-to-digital converter (ADC) is presented. A standard flash uses a resistor string to set individual comparator trip points. A stochastic flash ADC uses random comparator offset to set the trip points. Since the comparators are no longer sized for small offset, they can be shrunk down into digital cells. Using comparators that are implemented as digital cells

Skyler Weaver; Benjamin Hershberg; Peter Kurahashi; Daniel Knierim; Un-Ku Moon

2010-01-01

431

A Stochastic Model of Credit Sales Debt  

Microsoft Academic Search

This paper develops a stochastic model of accounts receivable, the debt arising from credit sales; and expresses the expectations and variances of (1) credit sales, (2) collections, (3) bad debts, (4) collections plus bad debts; and, (5) accounts receivable outstanding, in terms of parameters of the stochastic variables: (a) the number of credit sales made, (b) the size of sales;

Haskel Benishay

1966-01-01

432

QUANTUM STOCHASTIC CALCULUS AND QUANTUM NONLINEAR FILTERING  

E-print Network

QUANTUM STOCHASTIC CALCULUS AND QUANTUM NONLINEAR FILTERING V. P. BELAVKIN Abstract. A ?­algebraic inde...nite structure of quantum stochastic (QS) cal- culus is introduced and a continuity property...nitely dimensional nuclear space. The class of nondemolition output QS processes in quantum open systems

Belavkin, Viacheslav P.

433

SEMIMARTINGALE STOCHASTIC APPROXIMATION PROCEDURE AND RECURSIVE ESTIMATION  

Microsoft Academic Search

The semimartingale stochastic approximation procedure, na- mely, the Robbins-Monro type SDE is introduced which naturally includes both generalized stochastic approximation algorithms with martingale no- ises and recursive parameter estimation procedures for statistical models associated with semimartingales. General results concerning the asymp- totic behaviour of the solution are presented. In particular, the conditions ensuring the convergence, rate of convergence and asymptotic

N. LAZRIEVA; T. SHARIA; T. TORONJADZE

2007-01-01

434

Semimartingale Stochastic Approximation Procedures and Recursive Estimation  

Microsoft Academic Search

The semimartingale stochastic approximation procedure, namely, the Robbins-Monro type SDE is introduced which naturally includes both generalized stochastic approximation algorithms with martingale noises and recursive parameter estimation procedures for statistical models associated with semimartingales. General results concerning the asymptotic behaviour of the solution are presented. In particular, the conditions ensuring the convergence, rate of convergence and asymptotic expansion are established.

N. Lazrieva; T. Sharia; T. Toronjadze

2007-01-01

435

Semimartingale stochastic approximation procedure and recursive estimation  

Microsoft Academic Search

UDC 519.2 Abstract. The semimartingale stochastic approximation procedure, precisely, the Robbins-Monro type SDE, is introduced, which naturally includes both generalized stochastic approximation algorithms with martingale noises and recursive parameter estimation procedures for statistical models associated with semimartingales. General results concerning the asymptotic behavior of the solution are presented. In particular, the conditions ensuring the convergence, the rate of convergence, and

N. Lazrieva; T. Sharia; T. Toronjadze

2008-01-01

436

A contamination model for approximate stochastic order.  

E-print Network

satisfy the stochastic ordering. The minimal level of contam- ination that makes this approximate modelA contamination model for approximate stochastic order. Pedro C. ´Alvarez-Esteban1 , E. del Barrio1 to believe that a certain variable is somehow smaller than other. Instead of considering this rigid model

Cuesta, Juan Antonio

437

General frailty model and stochastic orderings  

Microsoft Academic Search

In this paper, we propose a general frailty model and develop its properties including some results for stochastic comparisons. More specifically, our main results lie in seeing how the well known stochastic orderings between distributions of two frailties translate into the orderings between the corresponding survival functions. These results are used to obtain the properties of the classical multiplicative frailty

Ramesh C. Gupta; Rameshwar D. Gupta

2009-01-01

438

Stochastic Hydrodynamics Department of Mathematics and  

E-print Network

force { one solution principle, vari- ational methods, master equations, generalized ows, reduction in Mathematics, Harvard University, December 2000. 1 #12; Contents 1 Introduction 3 2 Stochastic Burgers Equation recently on the mathemat- ical understanding of prototypical stochastic partial di#11;eren- tial equations

Torquato, Salvatore

439

Dynamical behaviour of stochastic dust charge fluctuations  

NASA Astrophysics Data System (ADS)

The dynamics of stochastic dust charge fluctuations is investigated. An inhomogeneous Burgers equation with a linear forcing term is derived in which the Burgers term is proportional to the diffusivity of dust charge fluctuations. This novel equation is solved analytically. Possibility of turbulence due to stochastic charge fluctuations is highlighted.

Ghosh, Samiran; Shukla, P. K.

2012-07-01

440

Stochastic Analysis of the Fractional Brownian Motion  

Microsoft Academic Search

Since the fractional Brownian motion is not a semi{martingale, the usual Ito calculus cannot be used to dene a full stochastic calculus. However, in this work, we obtain the It^ o formula, the It^ o{Clark rep- resentation formula and the Girsanov theorem for the functionals of a fractional Brownian motion using the stochastic calculus of variations.

L. Decreusefond

1996-01-01

441

Stochastic Analysis of the Fractional Brownian Motion  

Microsoft Academic Search

Since the fractional Brownian motion is not a semi-martingale, the usual Ito calculus cannot be used to define a full stochastic calculus. However, in this work, we obtain the Itô formula, the Itô–Clark representation formula and the Girsanov theorem for the functionals of a fractional Brownian motion using the stochastic calculus of variations.

L. Decreusefond; A. S. üstünel

1999-01-01

442

Stochastic Reduced Basis Methods for Uncertainty Quantification  

E-print Network

involved in stochastic analysis of the performance of a gas turbine blade. SRBMs have been successfully Turbine Blades In general, stochastic analysis (using SRBM) of any physical system involves two main steps the variability in the performance of a turbine blade in the presence of uncertainty. These blades operate

Sóbester, András

443

Research of Stochastic Robustness: Results and conclusions  

NASA Technical Reports Server (NTRS)

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.

Marrison, Chris

1995-01-01

444

Bayesian Selection of Multivariate Stochastic Volatility Models  

Microsoft Academic Search

We propose a Bayesian approach for selecting restrictions on multivariate regression models where the errors exhibit deterministic or stochastic volatilities. The model space is large and ex- haustive comparison of all possible restrictions is infeasible. We develop a Bayesian stochastic search method through Markov Chain Monte Carlo (MCMC) algorithms that generate posterior restrictions on the regression coe-cients and Cholesky decompositions

Antonello Loddo; Dongchu Sun

2006-01-01

445

Multistage stochastic optimization applied to energy planning  

Microsoft Academic Search

This paper presents a methodology for the solution of multistage stochastic optimization problems, based on the approximation of the expected-cost-to-go functions of stochastic dynamic programming by piecewise linear functions. No state discretization is necessary, and the combinatorial “explosion” with the number of states (the well known “curse of dimensionality” of dynamic programming) is avoided. The piecewise functions are obtained from

M. V. F. Pereira; L. M. V. G. Pinto

1991-01-01

446

From Complex to Simple: Interdisciplinary Stochastic Models  

ERIC Educational Resources Information Center

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…

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

2012-01-01

447

The stochastic background from cosmic (super)strings: popcorn and (Gaussian) continuous regimes  

E-print Network

In the era of the next generation of gravitational wave experiments a stochastic background from cusps of cosmic (super)strings is expected to be probed and, if not detected, to be significantly constrained. A popcorn-like background can be, for part of the parameter space, as pronounced as the (Gaussian) continuous contribution from unresolved sources that overlap in frequency and time. We study both contributions from unresolved cosmic string cusps over a range of frequencies relevant to ground based interferometers, such as LIGO/Virgo second generation (AdLV) and Einstein Telescope (ET) third generation detectors, the space antenna LISA and Pulsar Timing Arrays (PTA). We compute the sensitivity (at $2 \\sigma$ level) in the parameter space for AdLV, ET, LISA and PTA. We conclude that the popcorn regime is complementary to the continuous background. Its detection could therefore enhance confidence in a stochastic background detection and possibly help determine fundamental string parameters such as the strin...

Regimbau, Tania; Siemens, Xavier; Mandic, Vuk

2011-01-01

448

AdS pure spinor superstring in constant backgrounds  

E-print Network

In this paper we study the pure spinor formulation of the superstring in $AdS_5\\times S^5$ around point particle solutions of the classical equations of motion. As a particular example we quantize the pure spinor string in the BMN background.

Osvaldo Chandia; L. Ibiapina Bevilaqua; Brenno Carlini Vallilo

2014-04-03

449

Adding patents v4 1 myPublications: Adding patents  

E-print Network

Adding patents v4 1 myPublications: Adding patents You can use myPublications to record details of all your different research outputs, including patents. The system does not automatically search any patent databases so it is necessary for you to enter them manually. 1. On your Home screen click

Oakley, Jeremy

450

Tachyonic perturbations in AdS5 orbifolds Cyril Cartier  

E-print Network

for a theory of quantum gravity, is consis- tent only in ten space-time dimensions (11 dimensions for M contains a so-called "warp fac- tor". An especially attractive model of this type, where the bulk is a 5-dimensional anti-de Sitter (AdS5 ) space has been developed by Randall and Sundrum [14]. This is the model

Durrer, Ruth

451

Renormalized AdS action and Critical Gravity  

NASA Astrophysics Data System (ADS)

It is shown that the renormalized action for AdS gravity in even spacetime dimensions is equivalent -on shell- to a polynomial of the Weyl tensor, whose first non-vanishing term is proportional to $Weyl^2$. Remarkably enough, the coupling of this last term coincides with the one that appears in Critical Gravity.

Miskovic, Olivera; Tsoukalas, Minas; Olea, Rodrigo

2014-08-01

452

The complex interplay of sex allocation and sexual selection.  

PubMed

It is well recognized that sex allocation strategies can be influenced by sexual selection, when females adjust offspring sex ratios in response to their mates' attractiveness. Yet the reciprocal influence of strategic sex allocation on processes of sexual selection has only recently been revealed. Recent theoretical work demonstrates that sex allocation weakens selection for female preferences, leading to the decline of male traits. However, these results have been derived assuming that females have perfect knowledge of mate attractiveness and precise control over cost-free allocation. Relaxing these assumptions highlights the importance of another feedback: that adaptive sex allocation must become difficult to maintain as traits and preferences decline. When sex allocation strategies erode not only traits and preferences but also their own selective advantage, predictions can no longer be expressed as a simple linear correlation between ornament exaggeration and adaptive sex allocation. Instead, strongest sex ratio biases may be found at intermediate trait levels. PMID:23461318

Booksmythe, Isobel; Schwanz, Lisa E; Kokko, Hanna

2013-03-01

453

Stochastic ion acceleration by beating electrostatic waves.  

PubMed

A study is presented of the stochasticity in the orbit of a single, magnetized ion produced by the particle's interaction with two beating electrostatic waves whose frequencies differ by the ion cyclotron frequency. A second-order Lie transform perturbation theory is employed in conjunction with a numerical analysis of the maximum Lyapunov exponent to determine the velocity conditions under which stochasticity occurs in this dynamical system. Upper and lower bounds in ion velocity are found for stochastic orbits with the lower bound approximately equal to the phase velocity of the slower wave. A threshold condition for the onset of stochasticity that is linear with respect to the wave amplitudes is also derived. It is shown that the onset of stochasticity occurs for beating electrostatic waves at lower total wave energy densities than for the case of a single electrostatic wave or two nonbeating electrostatic waves. PMID:23410446

Jorns, B; Choueiri, E Y

2013-01-01

454

Optimality, stochasticity, and variability in motor behavior  

PubMed Central

Recent theories of motor control have proposed that the nervous system acts as a stochastically optimal controller, i.e. it plans and executes motor behaviors taking into account the nature and statistics of noise. Detrimental effects of noise are converted into a principled way of controlling movements. Attractive aspects of such theories are their ability to explain not only characteristic features of single motor acts, but also statistical properties of repeated actions. Here, we present a critical analysis of stochastic optimality in motor control which reveals several difficulties with this hypothesis. We show that stochastic control may not be necessary to explain the stochastic nature of motor behavior, and we propose an alternative framework, based on the action of a deterministic controller coupled with an optimal state estimator, which relieves drawbacks of stochastic optimality and appropriately explains movement variability. PMID:18202922

Guigon, Emmanuel; Baraduc, Pierre; Desmurget, Michel

2008-01-01

455

Fundamentals of higher order stochastic equations  

NASA Astrophysics Data System (ADS)

Stochastic processes that correspond to equations of arbitrary differential order are obtained. We show that stochastic paths in a complex extension of the original phase-space allow an implementation of such higher-order derivative terms. The resulting stochastic process is equivalent to the original partial differential equation in the sense of having equivalent analytic moments. However, the correspondence has unusual properties. Only the analytic moments are convergent, while non-analytic moments such as the complex moduli are non-convergent. These results unify previous approaches that transform higher-derivative equations into probabilistic stochastic equations. Larger ensembles are required as time-steps are reduced, giving these equations unusual convergence properties. This type of process is relevant to the question of how to obtain stochastic quantum simulations using the Wigner representation.

Drummond, P. D.

2014-08-01

456

Stochastic models for cell division  

NASA Astrophysics Data System (ADS)

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.

Stukalin, Evgeny; Sun, Sean

2013-03-01

457

Stochastic Methods for Aircraft Design  

NASA Technical Reports Server (NTRS)

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.

Pelz, Richard B.; Ogot, Madara

1998-01-01

458

Basic Principles of Stochastic Transport  

SciTech Connect

Transport in stochastic magnetic fields is reviewed. In the first part, the topic is motivated by commenting on the intricatenesses of known (nonlinear) transport theories. In the second part, non-integrable magnetic field line systems, their generation and Hamiltonian description are discussed. The symplectic mapping is introduced as the adequate tool for the analysis of the statistics of magnetic field lines. Transport along the unstable and stable manifolds of hyperbolic fixed points is an effective mechanism for heat transfer from the hot core to the plasma boundary. The third part deals with anomalous test particle transport theories starting from stochastic Liouville-type models. Several theories are based on the V-Langevin equation in the guiding center limit. In fusion devices, the mean magnetic fields are sufficiently strong to support the small gyro-radii assumption over a broad area, at least for the electrons. The question remains in what way finite Larmor radii influence the transport, especially in regions where the guiding center assumption fails. Indeed, in tokamaks such areas can be found, e.g. in the vicinity of hyperbolic points. Then, the more general A-Langevin equation has to be used. Based on the latter description, first for small Kubo numbers, the well known transport coefficients (formulated by Rechester and Rosenbluth, Kadomtsev and Pogutse, and others) are recovered. Second, for large Kubo numbers, new transport regimes are identified.

Spatschek, K. H. [Institut fuer Theoretische Physik, Heinrich-Heine-Universitaet Duesseldorf D-40225 Duesseldorf (Germany)

2008-05-14

459

ADS's Dexter Data Extraction Applet  

Microsoft Academic Search

The NASA Astrophysics Data System (ADS) now holds 1.3 million scanned pages, containing numerous plots and figures for which the original data sets are lost or inaccessible. The availability of scans of the figures can significantly ease the regeneration of the data sets. For this purpose, the ADS has developed Dexter, a Java applet that supports the user in this

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

2001-01-01

460

The ADS Bibliographic Reference Resolver  

Microsoft Academic Search

An increasingly larger number of publishers and institutions are using the NASA Astrophysics Data System (ADS) to verify the existence and availability of references published in the astronomical literature. In this paper we discuss the tools and utilities that the ADS is developing to provide the capability to automatically parse, identify, and verify the existence and correctness of citations appearing

Alberto Accomazzi; Guenther Eichhorn; M. J. Kurtz; C. S. Grant; Stephen S. Murray

1999-01-01

461

Usual Intake of Added sugars  

Cancer.gov

Usual Intake of Added sugars Table A40. Added sugars: Means, percentiles and standard errors of usual intake, 2007-2010 Age (Years) N1 teaspoons3 Mean (SE)2 5% (SE) 10% (SE) 25% (SE) 50% (SE) 75% (SE) 90% (SE) 95% (SE) Males 1-3 774 9.4 (0.31) 3.1 (0.17) 4.1

462

Adding Sections, Pages, Modules & Media  

E-print Network

COLLECT: Adding Sections, Pages, Modules & Media #12;Part 5: Add Sections, Pages & Modules #12 if you change your mind.) #12;Part 6: Add Media #12;1. Here we've added a Rich Text module. In order to put media into the module, you will need to click on the Edit tab. #12;2. From this page, you can: 1

Goldberg, Bennett

463

Self-dual warped AdS3 black holes  

NASA Astrophysics Data System (ADS)

We study a new class of solutions of three-dimensional topological massive gravity. These solutions can be taken as nonextremal black holes, with their extremal counterparts being discrete quotients of spacelike warped AdS3 along the U(1)L isometry. We study the thermodynamics of these black holes and show that the first law is satisfied. We also show that for consistent boundary conditions, the asymptotic symmetry generators form only one copy of the Virasoro algebra with central charge cL=(4??)/(G(?2+3)), with which the Cardy formula reproduces the black hole entropy. We compute the real-time correlators of scalar perturbations and find a perfect match with the dual conformal field theory (CFT) predictions. Our study provides a novel example of warped AdS/CFT correspondence: the self-dual warped AdS3 black hole is dual to a CFT with nonvanishing left central charge. Moreover, our investigation suggests that the quantum topological massive gravity asymptotic to the same spacelike warped AdS3 in different consistent ways may be dual to different two-dimensional CFTs.

Chen, Bin; Ning, Bo

2010-12-01

464

Moduli spaces in AdS 4 supergravity  

NASA Astrophysics Data System (ADS)

We study the structure of the supersymmetric moduli spaces of = 1 and = 2 supergravity theories in AdS 4 backgrounds. In the = 1 case, the moduli space cannot be a complex submanifold of the Kähler field space, but is instead real with respect to the inherited complex structure. In = 2 supergravity the same result holds for the vector multiplet moduli space, while the hypermultiplet moduli space is a Kähler submanifold of the quaternionic-Kähler field space. These findings are in agreement with AdS/CFT considerations.

de Alwis, Senarath; Louis, Jan; McAllister, Liam; Triendl, Hagen; Westphal, Alexander

2014-05-01

465

Reproductive allocation patterns in different density populations of spring wheat.  

PubMed

The effects of increased intraspecific competition on size hierarchies (size inequality) and reproductive allocation were investigated in populations of the annual plant, spring wheat (Triticum aestivum). A series of densities (100, 300, 1000, 3000 and 10,000 plants/m(2)) along a gradient of competition intensity were designed in this experiment. The results showed that average shoot biomass decreased with increased density. Reproductive allocation was negatively correlated to Gini coefficient (R(2) = 0.927), which suggested that reproductive allocation is inclined to decrease as size inequality increases. These results suggest that both vegetative and reproductive structures were significantly affected by intensive competition. However, results also indicated that there were different relationships between plant size and reproductive allocation pattern in different densities. In the lowest density population, lacking competition (100 plants/m(2)), individual reproductive allocation was size independent but, in high density populations (300, 1000, 3000 and 10,000 plants/m(2)), where competition occurred, individual reproductive allocation was size dependent: the small proportion of larger individuals were winners in competition and got higher reproductive allocation (lower marginal reproductive allocation; MRA), and the larger proportion of smaller individuals were suppressed and got lower reproductive allocation (higher MRA). In conclusion, our results support the prediction that elevated intraspecific competition would result in higher levels of size inequality and decreased reproductive allocation (with a negative relationship between them). However, deeper analysis indicated that these frequency- and size-dependent reproductive strategies were not evolutionarily stable strategies. PMID:18713435

Liu, Jing; Wang, Gen-Xuan; Wei, Liang; Wang, Chun-Ming

2008-02-01

466

Multisensory fusion and the stochastic structure of postural sway.  

PubMed

We analyze the stochastic structure of postural sway and demonstrate that this structure imposes important constraints on models of postural control. Linear stochastic models of various orders were fit to the center-of-mass trajectories of subjects during quiet stance in four sensory conditions: (i) light touch and vision, (ii) light touch, (iii) vision, and (iv) neither touch nor vision. For each subject and condition, the model of appropriate order was determined, and this model was characterized by the eigenvalues and coefficients of its autocovariance function. In most cases, postural-sway trajectories were similar to those produced by a third-order model with eigenvalues corresponding to a slow first-order decay plus a faster-decaying damped oscillation. The slow-decay fraction, which we define as the slow-decay autocovariance coefficient divided by the total variance, was usually near 1. We compare the stochastic structure of our data to two linear control-theory models: (i) a proportional-integral-derivative control model in which the postural system's state is assumed to be known, and (ii) an optimal-control model in which the system's state is estimated based on noisy multisensory information using a Kalman filter. Under certain assumptions, both models have eigenvalues consistent with our results. However, the slow-decay fraction predicted by both models is less than we observe. We show that our results are more consistent with a modification of the optimal-control model in which noise is added to the computations performed by the state estimator. This modified model has a slow-decay fraction near 1 in a parameter regime in which sensory information related to the body's velocity is more accurate than sensory information related to position and acceleration. These findings suggest that: (i) computation noise is responsible for much of the variance observed in postural sway, and (ii) the postural control system under the conditions tested resides in the regime of accurate velocity information. PMID:12386742

Kiemel, Tim; Oie, Kelvin S; Jeka, John J

2002-10-01

467

Poisson and Diffusion Approximation of Stochastic Schrodinger Equations with Control  

E-print Network

Poisson and Diffusion Approximation of Stochastic Schr¨odinger Equations with Control Cl of stochastic differential equations. Such equations are called "Stochastic Schr¨odinger Equations" and describe called "Stochastic Schr¨odinger Equations". Essentially, two kind of equations are considered: 1

Boyer, Edmond

468

A physical approach to structural stochastic optimal controls  

Microsoft Academic Search

The generalized density evolution equation proposed in recent years profoundly reveals the intrinsic connection between deterministic systems and stochastic systems by introducing physical relationships into stochastic systems. On this basis, a physical stochastic optimal control scheme of structures is developed in this paper, which extends the classical stochastic optimal control methods, and can govern the evolution details of system performance,

Jie Li; Yong-Bo Peng; Jian-Bing Chen

2010-01-01

469

Stochastic Inflation and Inflationary Density Fluctuations  

NASA Astrophysics Data System (ADS)

We examine the stochastic dynamics of chaotic inflation. The nonlinear stochastic behavior of inflation is studied with an emphasis on possible non-Gaussian statistics in initial conditions for cosmological large scale structure formation. Large scale non-random phase correlations and interesting dynamical features are analyzed using stochastic dynamics. We solve the stochastic evolution equations for the inflation field during the slow-roll period of chaotic inflation. We find exact analytic solutions for the quartic potential. Although the resulting statistics of the scalar field fluctuations are non-Gaussian, the current cosmic microwave constraint on the strength of the self-coupling for adiabatic fluctuations makes non -Gaussian effects negligibly small. Coarse-grained (long wavelength) scalar fields in stochastic dynamics become nonlinear stochastic variables whose stochastic random evolution is derived from generation and addition of short wave-length quantum noises. The interplay between the classical roll-down and quantum fluctuations makes the evolution of the scalar fields nonclassical. Only during the very late stage of inflation do the fields acquire their classical interpretation. The statistics of initial conditions for cosmological density fluctuations depend on the details of scalar field dynamics during inflation. We point out that initial conditions for large scale structure in inflationary scenarios with the simplest models are Gaussian to a high precision. However, as we consider more finely tuned models of inflation designed to yield special power spectra, Gaussian initial conditions should not be taken for granted, even on astrophysically interesting scales. We use stochastic dynamics to examine the probability of successful inflation from various initial conditions at the Planck epoch. The slow-roll stochastic framework is extended to non-slow-roll evolution. The well-known classical slow-roll attractors exist even when large quantum fluctuations are included. However, a significant fraction of the initial condition phase space which leads to a successful inflationary stage in the classical analysis fails to inflate.

Yi, In Su.

1992-01-01

470

Solving stochastic epidemiological models using computer algebra  

NASA Astrophysics Data System (ADS)

Mathematical modeling in Epidemiology is an important tool to understand the ways under which the diseases are transmitted and controlled. The mathematical modeling can be implemented via deterministic or stochastic models. Deterministic models are based on short systems of non-linear ordinary differential equations and the stochastic models are based on very large systems of linear differential equations. Deterministic models admit complete, rigorous and automatic analysis of stability both local and global from which is possible to derive the algebraic expressions for the basic reproductive number and the corresponding epidemic thresholds using computer algebra software. Stochastic models are more difficult to treat and the analysis of their properties requires complicated considerations in statistical mathematics. In this work we propose to use computer algebra software with the aim to solve epidemic stochastic models such as the SIR model and the carrier-borne model. Specifically we use Maple to solve these stochastic models in the case of small groups and we obtain results that do not appear in standard textbooks or in the books updated on stochastic models in epidemiology. From our results we derive expressions which coincide with those obtained in the classical texts using advanced procedures in mathematical statistics. Our algorithms can be extended for other stochastic models in epidemiology and this shows the power of computer algebra software not only for analysis of deterministic models but also for the analysis of stochastic models. We also perform numerical simulations with our algebraic results and we made estimations for the basic parameters as the basic reproductive rate and the stochastic threshold theorem. We claim that our algorithms and results are important tools to control the diseases in a globalized world.

Hincapie, Doracelly; Ospina, Juan

2011-06-01

471

AdS plane waves, entanglement and mutual information  

E-print Network

$AdS$ plane wave backgrounds are dual to CFT excited states with energy momentum density $T_{++}=Q$. Building on previous work on entanglement entropy in these and nonconformal brane plane wave backgrounds, we first describe a phenomenological scaling picture for entanglement in terms of "entangling partons". We then study aspects of holographic mutual information in these backgrounds for two strip shaped subsystems, aligned parallel or orthogonal to the flux. We focus on the wide ($Ql^d\\gg 1$) and narrow ($Ql^d\\ll 1$) strip regimes. In the wide strip regime, mutual information exhibits growth with the individual strip sizes and a disentangling transition as the separation between the strips increases, whose behaviour is distinct from the ground and thermal states. In the narrow strip case, our calculations have parallels with "entanglement thermodynamics" for these $AdS$ plane wave deformations. We also discuss some numerical analysis.

Debangshu Mukherjee; K. Narayan

2014-05-14

472

Thermodynamics of Einstein-Proca AdS black holes  

NASA Astrophysics Data System (ADS)

We study static spherically-symmetric solutions of the Einstein-Proca equations in the presence of a negative cosmological constant. We show that the theory admits solutions describing both black holes and also solitons in an asymptotically AdS background. Interesting subtleties can arise in the computation of the mass of the solutions and also in the derivation of the first law of thermodynamics. We make use of holographic renormalisation in order to calculate the mass, even in cases where the solutions have a rather slow approach to the asymptotic AdS geometry. By using the procedure developed by Wald, we derive the first law of thermodynamics for the black hole and soliton solutions. This includes a non-trivial contribution associated with the Proca "charge". The solutions cannot be found analytically, and so we make use of numerical integration techniques to demonstrate their existence.

Liu, Hai-Shan; Lü, H.; Pope, C. N.

2014-06-01

473

New boundary conditions for AdS3  

NASA Astrophysics Data System (ADS)

New chiral boundary conditions are found for quantum gravity with matter on AdS3. The associated asymptotic symmetry group is generated by a single right-moving U(1) Kac-Moody-Virasoro algebra with {c_R}={3?}/2G . The Kac-Moody zero mode generates global left-moving translations and equals, for a BTZ black hole, the sum of the total mass and spin. The level is positive about the global vacuum and negative in the black hole sector, corresponding to ergosphere formation. Realizations arising in Chern-Simons gravity and string theory are analyzed. The new boundary conditions are shown to naturally arise for warped AdS3 in the limit that the warp parameter is taken to zero.

Compère, Geoffrey; Song, Wei; Strominger, Andrew

2013-05-01

474

Warped AdS3/dipole-CFT duality  

NASA Astrophysics Data System (ADS)

String theory contains solutions with {{SL}}( {{2},{R}} ){{R}} × {{U}}{( {1} )_L} -invariant warped AdS3 (WAdS3) factors arising as continuous deformations of ordinary AdS3 factors. We propose that some of these are holographically dual to the IR limits of nonlocal dipole-deformed 2D D-brane gauge theories, referred to as "dipole CFTs". Neither the bulk nor boundary theories are currently well-understood, and consequences of the proposed duality for both sides is investigated. The bulk entropy-area law suggests that dipole CFTs have (at large N) a high-energy density of states which does not depend on the deformation parameter. Putting the boundary theory on a spatial circle leads to closed timelike curves in the bulk, suggesting a relation of the latter to dipole-type nonlocality.

Song, Wei; Strominger, Andrew

2012-05-01

475

Stochastic processes and conformal invariance  

NASA Astrophysics Data System (ADS)

We discuss a one-dimensional model of a fluctuating interface with a dynamic exponent z=1. The events that occur are adsorption, which is local, and desorption which is nonlocal and may take place over regions of the order of the system size. In the thermodynamic limit, the time dependence of the system is given by characters of the c=0 logarithmic conformal field theory of percolation. This implies in a rigorous way, a connection between logarithmic conformal field theory and stochastic processes. The finite-size scaling behavior of the average height, interface width and other observables are obtained. The avalanches produced during desorption are analyzed and we show that the probability distribution of the avalanche sizes obeys finite-size scaling with new critical exponents.

Gier, Jan De; Nienhuis, Bernard; Pearce, Paul A.; Rittenberg, Vladimir

2003-01-01

476

Stochastic sensing through covalent interactions  

DOEpatents

A system and method for stochastic sensing in which the analyte covalently bonds to the sensor element or an adaptor element. If such bonding is irreversible, the bond may be broken by a chemical reagent. The sensor element may be a protein, such as the engineered P.sub.SH type or .alpha.HL protein pore. The analyte may be any reactive analyte, including chemical weapons, environmental toxins and pharmaceuticals. The analyte covalently bonds to the sensor element to produce a detectable signal. Possible signals include change in electrical current, change in force, and change in fluorescence. Detection of the signal allows identification of the analyte and determination of its concentration in a sample solution. Multiple analytes present in the same solution may be detected.

Bayley, Hagan; Shin, Seong-Ho; Luchian, Tudor; Cheley, Stephen

2013-03-26

477

Improved bounds for stochastic matching  

E-print Network

In this paper we study stochastic matching problems that are motivated by applications in online dating and kidney exchange programs. We consider two probing models: edge probing and matching probing. Our main result is an algorithm that finds a matching-probing strategy attaining a small constant approximation ratio. An interesting aspect of our approach is that we compare the cost our solution to the best edge-probing strategy. Thus, we indirectly show that the best matching-probing strategy is only a constant factor away from the best edge-probing strategy. Even though our algorithm has a slightly worse approximation ratio than a greedy algorithm for edge-probing strategies, we show that the two algorithms can be combined to get improved approximations.

Li, Jian

2010-01-01

478

Heuristic-biased stochastic sampling  

SciTech Connect

This paper presents a search technique for scheduling problems, called Heuristic-Biased Stochastic Sampling (HBSS). The underlying assumption behind the HBSS approach is that strictly adhering to a search heuristic often does not yield the best solution and, therefore, exploration off the heuristic path can prove fruitful. Within the HBSS approach, the balance between heuristic adherence and exploration can be controlled according to the confidence one has in the heuristic. By varying this balance, encoded as a bias function, the HBSS approach encompasses a family of search algorithms of which greedy search and completely random search are extreme members. We present empirical results from an application of HBSS to the realworld problem of observation scheduling. These results show that with the proper bias function, it can be easy to outperform greedy search.

Bresina, J.L. [NASA Ames Research Center, Moffett Field, CA (United States)

1996-12-31

479

Stochastic dynamics of dengue epidemics  

NASA Astrophysics Data System (ADS)

We use a stochastic Markovian dynamics approach to describe the spreading of vector-transmitted diseases, such as dengue, and the threshold of the disease. The coexistence space is composed of two structures representing the human and mosquito populations. The human population follows a susceptible-infected-recovered (SIR) type dynamics and the mosquito population follows a susceptible-infected-susceptible (SIS) type dynamics. The human infection is caused by infected mosquitoes and vice versa, so that the SIS and SIR dynamics are interconnected. We develop a truncation scheme to solve the evolution equations from which we get the threshold of the disease and the reproductive ratio. The threshold of the disease is also obtained by performing numerical simulations. We found that for certain values of the infection rates the spreading of the disease is impossible, for any death rate of infected mosquitoes.

de Souza, David R.; Tomé, Tânia; Pinho, Suani T. R.; Barreto, Florisneide R.; de Oliveira, Mário J.

2013-01-01

480

Stochastic dynamics of cancer initiation  

NASA Astrophysics Data System (ADS)

Most human cancer types result from the accumulation of multiple genetic and epigenetic alterations in a single cell. Once the first change (or changes) have arisen, tumorigenesis is initiated and the subsequent emergence of additional alterations drives progression to more aggressive and ultimately invasive phenotypes. Elucidation of the dynamics of cancer initiation is of importance for an understanding of tumor evolution and cancer incidence data. In this paper, we develop a novel mathematical framework to study the processes of cancer initiation. Cells at risk of accumulating oncogenic mutations are organized into small compartments of cells and proliferate according to a stochastic process. During each cell division, an (epi)genetic alteration may arise which leads to a random fitness change, drawn from a probability distribution. Cancer is initiated when a cell gains a fitness sufficiently high to escape from the homeostatic mechanisms of the cell compartment. To investigate cancer initiation during a human lifetime, a 'race' between this fitness process and the aging process of the patient is considered; the latter is modeled as a second stochastic Markov process in an aging dimension. This model allows us to investigate the dynamics of cancer initiation and its dependence on the mutational fitness distribution. Our framework also provides a methodology to assess the effects of different life expectancy distributions on lifetime cancer incidence. We apply this methodology to colorectal tumorigenesis while considering life expectancy data of the US population to inform the dynamics of the aging process. We study how the probability of cancer initiation prior to death, the time until cancer initiation, and the mutational profile of the cancer-initiating cell depends on the shape of the mutational fitness distribution and life expectancy of the population.

Foo, Jasmine; Leder, Kevin; Michor, Franziska

2011-02-01

481

Self-dual warped AdS3 black holes  

Microsoft Academic Search

We study a new class of solutions of three-dimensional topological massive gravity. These solutions can be taken as nonextremal black holes, with their extremal counterparts being discrete quotients of spacelike warped AdS3 along the U(1)L isometry. We study the thermodynamics of these black holes and show that the first law is satisfied. We also show that for consistent boundary conditions,

Bin Chen; Bo Ning

2010-01-01

482

Supersymmetric giant graviton solutions in AdS3  

Microsoft Academic Search

We parametrize all classical probe brane configurations that preserve four supersymmetries in (a) the extremal D1-D5 geometry, (b) the extremal D1-D5-P geometry, (c) the smooth D1-D5 solutions proposed by Lunin and Mathur, and (d) global AdS3×S3×T4\\/K3. These configurations consist of D1 branes, D5 branes, and bound states of D5 and D1 branes with the property that a particular Killing vector

Gautam Mandal; Suvrat Raju; Mikael Smedbäck

2008-01-01

483

Geometries with Killing Spinors and Supersymmetric AdS Solutions  

Microsoft Academic Search

The seven and nine dimensional geometries associated with certain classes of supersymmetric AdS\\u000a 3 and AdS\\u000a 2 solutions of type IIB and D = 11 supergravity, respectively, have many similarities with Sasaki-Einstein geometry. We further elucidate their properties\\u000a and also generalise them to higher odd dimensions by introducing a new class of complex geometries in 2n + 2 dimensions, specified by a Riemannian metric,

Jerome P. Gauntlett; Nakwoo Kim

2008-01-01

484

Stochastic processes for line shapes and intensities  

NASA Astrophysics Data System (ADS)

Stochastic processes provide flexible and fast calculations for modeling dynamical interactions between an atom and charged particles. We use a stochastic renewal process for the plasma microfield being the cause of Stark broadening. The accuracy and improvement possibilities of Lyman profiles calculations with a renewal process are analyzed by comparing to ab initio simulations for ion broadening only. Stochastic processes may also be applied to out of equilibrium plasmas. We present our first results for the effect of Langmuir waves on a line broadened by electrons only, and for the changes of atomic populations submitted to strong temperature fluctuations.

Stamm, R.; Hammami, R.; Hannachi, I.; Capes, H.; Godbert-Mouret, L.; Koubiti, M.; Marandet, Y.; Rosato, J.

2014-10-01

485

Stochastic system identification in structural dynamics  

USGS Publications Warehouse

Recently, new identification methods have been developed by using the concept of optimal-recursive filtering and stochastic approximation. These methods, known as stochastic identification, are based on the statistical properties of the signal and noise, and do not require the assumptions of current methods. The criterion for stochastic system identification is that the difference between the recorded output and the output from the identified system (i.e., the residual of the identification) should be equal to white noise. In this paper, first a brief review of the theory is given. Then, an application of the method is presented by using ambient vibration data from a nine-story building.

Safak, Erdal

1988-01-01

486

SUSY properties of warped AdS3  

NASA Astrophysics Data System (ADS)

We examine supersymmetric properties of null-warped AdS3, or alternatively Schrödinger geometries, dual to putative warped CFTs in two dimensions. We classify super Schrödinger subalgebras of the superalgebra psu(1, 1|2) ? psu(1, 1|2), corresponding to the superconformal algebra of the AdS3 × S3 geometry. We comment on geometric realisations and provide a string theory description with enhanced supersymmetry in terms of intersecting D3-branes. For type IIB supergravity solutions based on T 1,1, we consider the relationship between five-dimensional Schrödinger solutions and their three-dimensional null-warped counterparts, corresponding to R symmetry twists. Finally, we study a family of null-warped AdS3 solutions in a setting where there is an ambiguity over the R symmetry and confirm that, for examples admitting a Kaluza-Klein (KK) reduction to three dimensions, the minimisation of a real superpotential of the three-dimensional gauged supergravity captures the central charge and R symmetry.

Jeong, Jaehoon; Colgáin, Eoin Ó.; Yoshida, Kentaroh

2014-06-01

487

N=2 AdS supergravity and supercurrents  

E-print Network

We consider the minimal off-shell formulation for four-dimensional N=2 supergravity with a cosmological term, in which the second compensator is an improved tensor multiplet. We use it to derive a linearized supergravity action (and its dual versions) around the anti-de Sitter (AdS) background in terms of three N=2 off-shell multiplets: an unconstrained scalar superfield, vector and tensor multiplets. This allows us to deduce the structure of the supercurrent multiplet associated with those supersymmetric theories which naturally couple to the supergravity formulation chosen, with or without a cosmological term. Finally, our linearized N=2 AdS supergravity action is reduced to N=1 superspace. The result is a sum of two N=1 linearized actions describing (i) old minimal supergravity; and (ii) an off-shell massless gravitino multiplet. We also derive dual formulations for the massless N=1 gravitino multiplet in AdS. As a by-product of our consideration, we derive the consistent supergravity extension of the N=1 ...

Butter, Daniel

2011-01-01

488

N=2 AdS supergravity and supercurrents  

E-print Network

We consider the minimal off-shell formulation for four-dimensional N=2 supergravity with a cosmological term, in which the second compensator is an improved tensor multiplet. We use it to derive a linearized supergravity action (and its dual versions) around the anti-de Sitter (AdS) background in terms of three N=2 off-shell multiplets: an unconstrained scalar superfield, vector and tensor multiplets. This allows us to deduce the structure of the supercurrent multiplet associated with those supersymmetric theories which naturally couple to the supergravity formulation chosen, with or without a cosmological term. Finally, our linearized N=2 AdS supergravity action is reduced to N=1 superspace. The result is a sum of two N=1 linearized actions describing (i) old minimal supergravity; and (ii) an off-shell massless gravitino multiplet. We also derive dual formulations for the massless N=1 gravitino multiplet in AdS. As a by-product of our consideration, we derive the consistent supergravity extension of the N=1 supercurrent multiplet advocated recently by Komargodski and Seiberg.

Daniel Butter; Sergei M. Kuzenko

2011-04-12

489

Classification of Boundary Gravitons in AdS$_3$ Gravity  

E-print Network

We revisit the description of the space of asymptotically AdS3 solutions of pure gravity in three dimensions with a negative cosmological constant as a collection of coadjoint orbits of the Virasoro group. Each orbit corresponds to a set of metrics related by diffeomorphisms which do not approach the identity fast enough at the boundary. Orbits contain more than a single element and this fact manifests the global degrees of freedom of AdS3 gravity, being each element of an orbit what we call boundary graviton. We show how this setup allows to learn features about the classical phase space that otherwise would be quite difficult. Most important are the proof of energy bounds and the characterization of boundary gravitons unrelated to BTZs and AdS3. In addition, it makes manifest the underlying mathematical structure of the space of solutions close to infinity. Notably, because of the existence of a symplectic form in each orbit, being this related with the usual Dirac bracket of the asymptotic charges, this ap...

Garbarz, A

2014-01-01

490

Online Resource Allocation Problems Patrick Jaillet  

E-print Network

and ad displays on-demand videos/movies kidney exchange programs 2 online optimization framework contexts on-demand videos/movies pj (mit) msis-rutgers & rutcor 4 / 30 #12;raft contexts kidney exchange

Jaillet, Patrick

491

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

Federal Register 2010, 2011, 2012, 2013

...subsidiary CDEs by no later than July 8, 2011 and Allocation Agreement Amendment...recommends use of Internet Explorer version 8 on Windows XP, and optimally at least a 56Kbps...Doc. 2011-13864 Filed 6-3-11; 8:45 am] BILLING CODE...

2011-06-06

492

On Stochastic Nonlinear Schrodinger Equations under Stochastic Complex Non-Homogeneity and Complex Initial Conditions  

SciTech Connect

In this paper, a stochastic nonlinear Schrodinger equation is studied under stochastic complex external forces in a limited time interval through general conditions. The analytical solution for the linear case is introduced. The WHEP technique is used to get approximate ensemble average of the stochastic solution process. Using Mathematica, the method of solution is illustrated through case studies and figures which demonstrate the effects of the input conditions.

El-Tawil, Magdy A. [Cairo university, Faculty of Engineering, Engineering Mathematics Department, Giza (Egypt)

2008-09-01

493

Impact of a Stochastic Energy Backscatter Scheme on Climate and Variability across Timescales and Resolutions  

NASA Astrophysics Data System (ADS)

Stochastic physics is one of most widely used methods to represent model uncertainty in ensemble prediction systems of weather and climate models. These schemes aim to represent absent or poorly simulated process whose scales are below the truncation scale, they have been proven to be a skilful tool against the common underdispersiveness (lack of internal variability) of these models, as well as theoretically able to improve the mean climate through a noise-induced drift (better variability leads to a better mean climate). However, the formulation of these schemes often relies in pragmatic assumptions with limited scientific basis, and their physical realism is often challenged. The stochastic energy backscatter method is one of the main formulations of stochastic physics. It is designed to stochastically simulate upscale cascades of energy coming from numerical dissipation, convective subgrid-scale events or subgrid mountain drag. This scheme has been successfully implemented in many of the most important numerical weather prediction models across the world. It improves the ensemble skill scores, and under some configurations the mean climate too. In order to understand the impacts of the stochastic energy backscatter concept in a deterministic framework, we use the Stochastic Kinetic Energy Backscatter (SKEB2) scheme in the Met Office Unified Model (MetUM). We explore the impact of SKEB2 across timescales and resolutions in terms of usual model evaluation metrics such as biases or root mean error square, as well as some process-based techniques to diagnose the simulation of tropical and extra-tropical variability, such as cyclone tracking, Lorenz Energy Cycle or Madden Julian Oscillation diagnostics. Our results show that the extra kinetic energy added by SKEB2 can improve the representation of key processes that drive the atmospheric variability, leading to a slight improvement of climate biases. However it degrades the skill of short-range (less than 5 days) deterministic forecasts.

Sanchez, C.

2012-12-01

494

Algorithms for hardware allocation in data path synthesis  

Microsoft Academic Search

Novel algorithms for the simultaneous cost\\/resource-constrained allocation of registers, arithmetic units, and interconnect in a data path have been developed. The entire allocation process can be formulated as a two-dimensional placement problem of microinstructions in space and time. This formulation readily lends itself to the use of a variety of heuristics for solving the allocation problem. The authors present simulated-annealing-based

Srinivas Devadas; A. Richard Newton

1989-01-01

495

Allocation of energy use in petroleum refineries to petroleum products  

Microsoft Academic Search

Aim, Scope, and Background  Studies to evaluate the energy and emission impacts of vehicle\\/fuel systems have to address allocation of the energy use and\\u000a emissions associated with petroleum refineries to various petroleum products because refineries produce multiple products.\\u000a The allocation is needed in evaluating energy and emission effects of individual transportation fuels. Allocation methods\\u000a used so far for petroleum-based fuels (e.g.,

Michael Wang; Hanjie Lee; John Molburg

2004-01-01

496

Quadratic Programming for Allocating Control Effort  

NASA Technical Reports Server (NTRS)

A computer program calculates an optimal allocation of control effort in a system that includes redundant control actuators. The program implements an iterative (but otherwise single-stage) algorithm of the quadratic-programming type. In general, in the quadratic-programming problem, one seeks the values of a set of variables that minimize a quadratic cost function, subject to a set of linear equality and inequality constraints. In this program, the cost function combines control effort (typically quantified in terms of energy or fuel consumed) and control residuals (differences between commanded and sensed values of variables to be controlled). In comparison with prior control-allocation software, this program offers approximately equal accuracy but much greater computational efficiency. In addition, this program offers flexibility, robustness to actuation failures, and a capability for selective enforcement of control requirements. The computational efficiency of this program makes it suitable for such complex, real-time applications as controlling redundant aircraft actuators or redundant spacecraft thrusters. The program is written in the C language for execution in a UNIX operating system.

Singh, Gurkirpal

2005-01-01

497

Resource allocation to reproduction in animals.  

PubMed

The standard Dynamic Energy Budget (DEB) model assumes that a fraction ? of mobilised reserve is allocated to somatic maintenance plus growth, while the rest is allocated to maturity maintenance plus maturation (in embryos and juveniles) or reproduction (in adults). All DEB parameters have been estimated for 276 animal species from most large phyla and all chordate classes. The goodness of fit is generally excellent. We compared the estimated values of ? with those that would maximise reproduction in fully grown adults with abundant food. Only 13% of these species show a reproduction rate close to the maximum possible (assuming that ? can be controlled), another 4% have ? lower than the optimal value, and 83% have ? higher than the optimal value. Strong empirical support hence exists for the conclusion that reproduction is generally not maximised. We also compared the parameters of the wild chicken with those of races selected for meat and egg production and found that the latter indeed maximise reproduction in terms of ?, while surface-specific assimilation was not affected by selection. We suggest that small values of ? relate to the down-regulation of maximum body size, and large values to the down-regulation of reproduction. We briefly discuss the ecological context for these findings. PMID:24517882

Kooijman, Sebastiaan A L M; Lika, Konstadia

2014-11-01

498

High efficiency thrust vector control allocation  

NASA Astrophysics Data System (ADS)

The design of control mixing algorithms for launch vehicles with multiple vectoring engines yields competing objectives for which no straightforward solution approach exists. The designer seeks to optimally allocate the effector degrees of freedom such that maneuvering capability is maximized subject to constraints on available control authority. In the present application, such algorithms are generally restricted to linear transformations so as to minimize adverse control-structure interaction and maintain compatibility with industry-standard methods for control gain design and stability analysis. Based on the application of the theory of ellipsoids, a complete, scalable, and extensible framework is developed to effect rapid analysis of launch vehicle capability. Furthermore, a control allocation scheme is proposed that simultaneously balances attainment of the maximum maneuvering capability with rejection of internal loads and performance losses resulting from thrust vectoring in the null region of the admissible controls. This novel approach leverages an optimal parametrization of the weighted least squares generalized inverse and exploits the analytic properties of the constraint geometry so as to enable recovery of more than ninety percent of the theoretical capability while maintaining linearity over the majority of the attainable set.

Orr, Jeb S.

499

Value-added measures for schools in England: looking inside the ‘black box’ of complex metrics  

Microsoft Academic Search

Value-added measures can be used to allocate funding to schools, to identify those institutions in need of special attention\\u000a and to underpin government guidance on targets. In England, there has been a tendency to include in these measures an ever-greater\\u000a number of contextualising variables and to develop ever-more complex models that encourage (or ‘impose’) in schools a single\\u000a uniform method

Anthony Kelly; Christopher Downey

2010-01-01

500

ADS/CFT and QCD  

SciTech Connect

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.

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

2007-02-21