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1

Solving Stochastic Nonlinear Resource Allocation Problems Using a Hierarchy of Twofold Resource Allocation Automata  

Microsoft Academic Search

In a multitude of real-world situations, resources must be allocated based on incomplete and noisy information. However, in many cases, incomplete and noisy information render traditional resource allocation techniques ineffective. The decentralized Learning Automata Knapsack Game (LAKG) was recently proposed for solving one such class of problems, namely the class of Stochastic Nonlinear Fractional Knapsack Problems. Empirically, the LAKG was

Ole-Christoffer Granmo; B. John Oommen

2010-01-01

2

Unexpected Patterns of Plastic Energy Allocation in Stochastic Environments  

PubMed Central

When environmental conditions vary stochastically, individuals accrue fitness benefits by exhibiting phenotypic plasticity. Here we analyze a general dynamic-programming model describing an individual’s optimal energy allocation in a stochastic environment. After maturation, individuals repeatedly decide how to allocate incoming energy between reproduction and maintenance. We analyze the optimal fraction of energy invested in reproduction and the resultant degree of plasticity in dependence on environmental variability and predictability. Our analyses reveal unexpected patterns of optimal energy allocation. When energy availability is low, all energy is allocated to reproduction, although this implies that individuals will not survive after reproduction. Above a certain threshold of energy availability, the optimal reproductive investment decreases to a minimum and even vanishes entirely in highly variable environments. With further improving energy availability, optimal reproductive investment gradually increases again. Costs of plasticity affect this allocation pattern only quantitatively. Our results show that optimal reproductive investment does not increase monotonically with growing energy availability and that small changes in energy availability can lead to major variations in optimal energy allocation. Our results help to unify two apparently opposing predictions from life-history theory, that organisms should increase reproductive investment both with improved environmental conditions and when conditions deteriorate (“terminal investment”).

Fischer, Barbara; Taborsky, Barbara; Dieckmann, Ulf

2012-01-01

3

Stochastic optimisation of water allocation on a global scale  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

4

Applying the Stochastic Programming with Recourse to water allocation analysis  

NASA Astrophysics Data System (ADS)

How to decide strategies implementation priority is an important issue when making decision. Strategies efficiency and cost is the main consideration for decision maker. Therefore, this study proposes a decision model which considering long-term and short-term strategies simultaneously to find out the best combination. The model precision requirement is different between long-term strategies and short-term strategies. That makes the analysis more complex and difficult. Hence, this study proposes a decision model based on stochastic programming with recourse to solving this puzzle and the model called SPRDM. The first stage is calculating water shortage and probability of short-term water shortage event by long-term water allocation simulation. The second stage is optimizing the best combination with minimum cost under water demand is fulfilled. SPRDM is suit for decision model because SPRDM can consider long-term strategy, short-term strategy and uncertainty factors. The results can be the reference when government makes decision.

Liou, K.; Ho, C.; Chang, L.

2012-12-01

5

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

6

Research of Power-Aware Dynamic Adaptive Replica Allocation Algorithm in Mobile Ad Hoc Networks  

Microsoft Academic Search

\\u000a Power conservation is a critical issue in mobile ad hoc networks, as the nodes are powered by batteries only. In this paper,\\u000a according to the mobility of nodes, the power-aware dynamic adaptive replica allocation algorithm is proposed. In the power-aware\\u000a dynamic adaptive replica allocation algorithm, based on the locality of data access, the replica allocation scheme is adjusted\\u000a regularly in

Yijie Wang; Kan Yang

2005-01-01

7

Online prophet-inequality matching with applications to ad allocation  

Microsoft Academic Search

We study the problem of online prophet-inequality matching in bipartite graphs. There is a static set of bidders and an online stream of items. We represent the interest of bidders in items by a weighted bipartite graph. Each bidder has a capacity, i.e., an upper bound on the number of items that can be allocated to her. The weight of

Saeed Alaei; MohammadTaghi Hajiaghayi; Vahid Liaghat

2012-01-01

8

Real-time bidding algorithms for performance-based display ad allocation  

Microsoft Academic Search

We describe a real-time bidding algorithm for performance-based display ad allocation. A central issue in performance display advertising is matching campaigns to ad impressions, which can be formulated as a constrained optimization problem that maximizes revenue subject to constraints such as budget limits and inventory availability. The current practice is to solve the optimization problem offline at a tractable level

Ye Chen; Pavel Berkhin; Bo Anderson; Nikhil R. Devanur

2011-01-01

9

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

2004-10-01

10

Mechanism Design for Stochastic Virtual Resource Allocation in Non-cooperative Cloud Systems  

Microsoft Academic Search

Currently, virtualization technology has been widely adopted by cloud service providers to provide flexible and cost- effective resource sharing among users. On cloud platforms, computing resources are allocated on-demand dynamically and the application hosted on a virtual machine(VM) usually has the illusion of complete control of resources. Thus, a selfish VM may strategically compete for resource with other VMs to

Zhen Kong; Cheng-Zhong Xu; Minyi Guo

2011-01-01

11

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

12

Biological Swarm Intelligence Based Opportunistic Resource Allocation for Wireless Ad Hoc Networks  

Microsoft Academic Search

Particle swarm optimization (PSO) is one of the most important biological swarm intelligence paradigms. However, the standard\\u000a PSO algorithm can easily get trapped in the local optima when solving complex multimodal problems. In this paper, an improved\\u000a adaptive particle swarm optimization (IAPSO) is presented. Based on IAPSO, a joint opportunistic power and rate allocation\\u000a (JOPRA) algorithm is proposed to maximize

Defang Liu; Bochu Wang

13

Static allocation of resources to communicating subtasks in a heterogeneous ad hoc grid environment  

Microsoft Academic Search

Abstract An ad hoc grid is a heterogeneous computing and communication system that allows a group of mobile devices to accomplish a mission, 15 often in a hostile environment. Energy management,is a major concern in ad hoc grids. The problem studied here focuses on statically assigning resources in an ad hoc grid to an application composed,of communicating,subtasks. The goal of

Sameer Shivle; Howard Jay Siegel; Anthony A. Maciejewski; Prasanna Sugavanam; Tarun Banka; Ralph H. Castain; Kiran Chindam; Steve Dussinger; Prakash Pichumani; Praveen Satyasekaran; William Saylor; David Sendek; J. Sousa; Jayashree Sridharan; José Velazco

2006-01-01

14

Exploring the Synergism of a Multiple Auction-Based Task Allocation Scheme for Power-Aware Intrusion Detection in Wireless Ad-Hoc Networks  

Microsoft Academic Search

In this paper we propose a multiple auction-based task allocation scheme for identifying and distributing network-monitoring and decision-making tasks amongst the various nodes in a wireless ad-hoc network for performing power-aware intrusion detection. By iteratively performing this scheme we show that a power-optimal solution can be reached in a bandwidth constrained and energy-preserving network with only the nodes capable of

T. Srinivasan; R. Chandrasekar; Vivek Vijaykumar; V. Mahadevan; A. Meyyappan; M. Nivedita

2006-01-01

15

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

NASA Astrophysics Data System (ADS)

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

Bekri, Eleni; Yannopoulos, Panayotis; Disse, Markus

2014-05-01

16

Online Stochastic Matching: Beating 1-1\\/e  

Microsoft Academic Search

We study the online stochastic bipartite matching problem, in a form\\u000amotivated by display ad allocation on the Internet. In the online, but\\u000aadversarial case, the celebrated result of Karp, Vazirani and Vazirani gives an\\u000aapproximation ratio of $1-1\\/e$. In the online, stochastic case when nodes are\\u000adrawn repeatedly from a known distribution, the greedy algorithm matches this\\u000aapproximation ratio,

Jon Feldman; Aranyak Mehta; Vahab S. Mirrokni; S. Muthukrishnan

2009-01-01

17

Online Stochastic Matching: Online Actions Based on Offline Statistics  

Microsoft Academic Search

We consider the online stochastic matching problem proposed by Feldman et al. [4] as a model of display ad allocation. We are given a bipartite graph; one side of the graph corresponds to a fixed set of bins and the other side represents the set of possible ball types. At each time step, a ball is sampled independently from the

Vahideh H. Manshadi; Shayan Oveis Gharan; Amin Saberi

2011-01-01

18

Mosaic-Net: a game theoretical method for selection and allocation of replicas in ad hoc networks  

Microsoft Academic Search

Due to the continuous mobility of hosts, an ad hoc network suffers from frequent disconnections. This phenomenon is undesirable\\u000a when mobile hosts are accessing data from each other, and thus, data accessibility is lower than that in conventional fixed\\u000a networks. Because one cannot control network disconnections, an alternative solution to this problem is to replicate data\\u000a objects onto mobile hosts

Samee Ullah Khan

2011-01-01

19

Online Stochastic Matching: Online Actions Based on Offline Statistics  

Microsoft Academic Search

We consider the online stochastic matching problem proposed by Feldman et al.\\u000a[FOCS'09], as a model of display ad allocation. We are given a bipartite graph;\\u000aone side of the graph corresponds to a fixed set of bins and the other side\\u000arepresents the set of possible ball types. At each time step, a ball is sampled\\u000aindependently from the

Vahideh H. ManshadiShayan; Shayan Oveis Gharan; Amin Saberi

2010-01-01

20

Stochastic Resonance  

NASA Astrophysics Data System (ADS)

Preface; 1. Introduction and motivation; 2. Stochastic resonance: its definitions, history and debates; 3. Stochastic quantization; 4. Suprathreshold stochastic resonance: encoding; 5. Suprathreshold stochastic resonance: large N encoding; 6. Suprathreshold stochastic resonance: decoding; 7. Suprathreshold stochastic resonance: large N decoding; 8. Optimal stochastic quantization; 9. SSR, neural coding, and performance tradeoffs; 10. Stochastic resonance in the auditory system; 11. The future of stochastic resonance and suprathreshold stochastic resonance; Appendices; References; Index.

McDonnell, Mark D.; Stocks, Nigel G.; Pearce, Charles E. M.; Abbott, Derek

2012-10-01

21

Models of Optimal File Allocation in a Distributed Data Base: A Survey. Classifies Distributed File Allocation Models and Describes the Parameters Needed in Modeling.  

National Technical Information Service (NTIS)

The report examines the existing distributed data base file allocation models and gives a breakdown of the models by type (deterministic one-phase, deterministic multi-phase, stochastic discrete, stochastic continuous). The relationships and identities us...

T. H. Crocker D. M. Klamer

1978-01-01

22

Policy Based Resource Allocation in Cloud Systems  

Microsoft Academic Search

Cloud Systems provide computing resources in a flexible manner. There are several key requirements that need to be addressed regarding the resource allocation in Clouds and the most important of them is providing on demand elasticity. This paper focuses on adding new features to the Cloud resource allocation mechanism that enhance on demand elasticity. Most of the resource managers that

Elena Apostol; Catalin Leordeanu; Valentin Cristea

2011-01-01

23

Optimal reactive power allocation  

SciTech Connect

A systematic procedure is developed to locate reactive power devices in a power system based on a set of indices, that are based on overall system conditions. After identifying the desired locations, the cost of installation and number of reactive power devices, subject to any required practical and real economic constraints are minimized. Existing controller are fully utilized before adding any new devices. Linearized sensitivity relationships of power systems are used to obtain an objective function for minimizing the cost of installation. The constraints include the limits on dependent variables (reactive powers of the generators, load bus voltages) and control variables (generator voltages, tap positions, switchable reactive power sources). A parametric linear programming technique based on active set analysis is proposed to solve the reactive power allocation problem.

Venkataramana, A.; Carr, J.; Ramshaw, R.S.

1987-02-01

24

Esaliency (Extended Saliency): Meaningful Attention Using Stochastic Image Modeling  

Microsoft Academic Search

Computer vision attention processes assign variable-hypothesized importance to different parts of the visual input and direct the allocation of computational resources. This nonuniform allocation might help accelerate the image analysis process. This paper proposes a new bottom-up attention mechanism. Rather than taking the traditional approach, which tries to model human attention, we propose a validated stochastic model to estimate the

Tamar Avraham; Michael Lindenbaum

2010-01-01

25

Resource Allocation Among Agents with MDP-Induced Preferences  

Microsoft Academic Search

Allocating scarce resources among agents to maximize global utility is, in general, com- putationally challenging. We focus on problems where resources enable agents to execute actions in stochastic environments, modeled as Markov decision processes (MDPs), such that the value of a resource bundle is defined as the expected value of the optimal MDP policy realizable given these resources. We present

Dmitri A. Dolgov; Edmund H. Durfee

2006-01-01

26

Predictive Control for Dynamic Resource Allocation in Enterprise Data Centers  

Microsoft Academic Search

It is challenging to reduce resource over-provisioning for enterprise applications while maintaining service level objectives (SLOs) due to their time-varying and stochastic workloads. In this paper, we study the effect of prediction on dynamic resource allocation to virtualized servers running enterprise applications. We present predictive controllers using three different prediction algorithms based on a standard auto- regressive (AR) model, a

Wei Xu; Xiaoyun Zhu; Sharad Singhal; Zhikui Wang

2006-01-01

27

Near optimal online algorithms and fast approximation algorithms for resource allocation problems  

Microsoft Academic Search

We present algorithms for a class of resource allocation problems both in the online setting with stochastic input and in the offline setting. This class of problems contains many interesting special cases such as the Adwords problem. In the online setting we introduce a new distributional model called the adversarial stochastic input model, which is a generalization of the i.i.d

Nikhil R. Devanur; Kamal Jain; Balasubramanian Sivan; Christopher A. Wilkens

2011-01-01

28

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

29

Optimal Capital Allocation Using RAROC And EVA  

Microsoft Academic Search

This paper analyzes financial institutions' capital allocation decisions when their required equity capital depends on the risk of their projects chosen. We discuss the relevance of strict position limits against discretionary trading through the use of an optimal compensation function. We show that (under full information) the first-best investment decision can be delegated through an economic value added (EVA) compensation

Neal Stoughton; Josef Zechner

1999-01-01

30

Competitive distributed file allocation  

Microsoft Academic Search

This paper deals with the file allocation problem (BFR92) con- cerning the dynamic optimization of communication costs to ac- cess data in a distributed environment. We develop a dynamic file re-allocation strategy that adapts online to a sequence of r ead and write requests whose location and relative frequencies are com- pletely unpredictable. This is achieved by replicating the file

Baruch Awerbuch; Yair Bartalt; Amos Fiati

1993-01-01

31

Competitive distributed file allocation  

Microsoft Academic Search

This paper deals with the file allocation problem [6] concerning the dynamic optimization of communication costs to access data in a distributed environment. We develop a dynamic file re-allocation strategy that adapts on-line to a sequence of read and write requests whose location and relative frequencies are completely unpredictable. This is achieved by replicating the file in response to read

Baruch Awerbuch; Yair Bartal; Amos Fiat

2003-01-01

32

The yard allocation problem  

Microsoft Academic Search

The Yard Allocation Problem (YAP) is a real-life resource allocation problem faced by the Port of Singapore Authority (PSA). We first show that YAP is NP-Hard. As the problem is NP-Hard, we propose several heuristics, including Tabu Search methods with short and long term memory, a \\

Ping Chen; Zhaohui Fu; Andrew Lim

33

The Yard Allocation Problem  

Microsoft Academic Search

The Yard Allocation Problem (YAP) is a real-life re- source allocation problem faced by the Port of Singa- pore Authority (PSA). We first show that YAP is NP- Hard. As the problem is NP-Hard, we propose several heuristics, including Tabu Search methods with short and long term memory, a \\

Ping Chen; Zhaohui Fu; Andrew Lim

2002-01-01

34

Linear scan register allocation  

Microsoft Academic Search

We describe a new algorithm for fast global register allocation called linear scan. This algorithm is not based on graph coloring, but allocates registers to variables in a single linear-time scan of the variables' live ranges. The linear scan algorithm is considerably faster than algorithms based on graph coloring, is simple to implement, and results in code that is almost

Massimiliano Poletto; Vivek Sarkar

1999-01-01

35

Stochastic resonance in electrical circuits. I. Conventional stochastic resonance  

Microsoft Academic Search

Stochastic resonance (SR), a phenomenon in which a periodic signal in a nonlinear system can be amplified by added noise, is introduced and discussed. Techniques for investigating SR using electronic circuits are described in practical terms. The physical nature of SR, and the explanation of weak-noise SR as a linear response phenomenon, are considered. Conventional SR, for systems characterized by

Dmitrii G. Luchinsky; Riccardo Mannella; Peter V. E. McClintock; Nigel G. Stocks

1999-01-01

36

The Allocative Efficiency Implications of Water Pollution Abatement Cost Comparisons  

NASA Astrophysics Data System (ADS)

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 distribution of emissions. Nevertheless, efficiency analyses involving stochastic emissions usually sidestep formal consideration of the stochastic element by measuring pollution control and control costs with respect to changes in long-term average flows. An economic model of stochastic emissions is used to demonstrate that this approach can give misleading results. An alternative procedure is briefly discussed.

Shortle, James S.

1990-05-01

37

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

38

Distributed Network Resource Allocation.  

National Technical Information Service (NTIS)

This thesis addresses several resource allocation problems that arise in the context of distributed networks. First, we present a scheme for accessing shared copies of objects in a network that has asymptotically optimal expected cost per access for a cla...

A. W. Richa

1998-01-01

39

Longwall Face Crew Selection With Respect to Stochastic Character of the Production Process - Part 2 - Calculation Example / Wyznaczanie obsady przodka ?cianowego z uwzgl?dnieniem stochastycznego charakteru procesu produkcyjnego cz. 2 - przyk?ad obliczeniowy  

NASA Astrophysics Data System (ADS)

A calculation example of the longwall face crew selection, including taking under consideration stochastic character of the production process is presented in this study. On the basis of observation of duration of activities realized in the hard coal mine longwall face with use of the roof cut and fill system, the calculations with use of the proposed crew selection method have been executed. The method in question takes into consideration stochastic character of the realized production process (Snopkowski & Sukiennik, 2012). In the final part of this study, graphical interpretation of the executed calculations has been presented.

Snopkowski, Ryszard; Sukiennik, Marta

2013-03-01

40

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.

41

The kidney allocation system.  

PubMed

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

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

2013-12-01

42

Sensory optimization by stochastic tuning.  

PubMed

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

2013-10-01

43

BM-Map: an efficient software package for accurately allocating multireads of RNA-sequencing data  

PubMed Central

Background RNA sequencing (RNA-seq) has become a major tool for biomedical research. A key step in analyzing RNA-seq data is to infer the origin of short reads in the source genome, and for this purpose, many read alignment/mapping software programs have been developed. Usually, the majority of mappable reads can be mapped to one unambiguous genomic location, and these reads are called unique reads. However, a considerable proportion of mappable reads can be aligned to more than one genomic location with the same or similar fidelities, and they are called "multireads". Allocating these multireads is challenging but critical for interpreting RNA-seq data. We recently developed a Bayesian stochastic model that allocates multireads more accurately than alternative methods (Ji et al. Biometrics 2011). Results In order to serve a greater biological community, we have implemented this method in a stand-alone, efficient, and user-friendly software package, BM-Map. BM-Map takes SAM (Sequence Alignment/Map), the most popular read alignment format, as the standard input; then based on the Bayesian model, it calculates mapping probabilities of multireads for competing genomic loci; and BM-Map generates the output by adding mapping probabilities to the original SAM file so that users can easily perform downstream analyses. The program is available in three common operating systems, Linux, Mac and PC. Moreover, we have built a dedicated website, http://bioinformatics.mdanderson.org/main/BM-Map, which includes free downloads, detailed tutorials and illustration examples. Conclusions We have developed a stand-alone, efficient, and user-friendly software package for accurately allocating multireads, which is an important addition to our previous methodology paper. We believe that this bioinformatics tool will greatly help RNA-seq and related applications reach their full potential in life science research.

2012-01-01

44

An Asset Allocation Puzzle  

Microsoft Academic Search

This paper examines popular advice on portfolio allocation among cash, bonds, and stocks. It documents that this advice is inconsistent with the mutual-fund separation theorem, which states that all investors should hold the same composition of risky assets. In contrast to the theorem, popular advisors recommend that aggressive investors hold a lower ratio of bonds to stocks than conservative investors.

Niko Canner; N. GREGORY MANKIW; DAVID N. WEIL

1997-01-01

45

The effective use of student time: a stochastic frontier production function case study  

Microsoft Academic Search

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

Peter Dolton; Oscar D. Marcenaro; Lucia Navarro

2003-01-01

46

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

ERIC Educational Resources Information Center

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

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

2003-01-01

47

Cost allocation in distribution planning.  

National Technical Information Service (NTIS)

This thesis concerns cost allocation problems in distribution planning. The cost allocation problems we study are illustrated using the distribution planning situation at the Logistics department of Norsk Hydro Olje AB. The planning situation is modeled a...

S. Engevall

1996-01-01

48

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

49

Fairness Measures for Resource Allocation  

Microsoft Academic Search

In many optimization problems, one seeks to allocate a limited set of resources to a set of individuals with demands. Thus, such allocations can naturally be viewed as vectors, with one coordinate representing each individual. Motivated by work in network routing and bandwidth assignment, we consider the problem of producing solutions that simultaneously approximate all feasible allocations in a coordinate-wise

Amit Kumar; Jon M. Kleinberg

2000-01-01

50

Stochastic Cooling  

SciTech Connect

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

Blaskiewicz, M.

2011-01-01

51

Stochastic desertification  

NASA Astrophysics Data System (ADS)

The process of desertification is usually modeled as a first-order transition, where a change of an external parameter (e.g., precipitation) leads to a catastrophic bifurcation followed by an ecological regime shift. However, vegetation elements like shrubs and trees undergo a stochastic birth-death process with an absorbing state; such a process supports a second-order continuous transition with no hysteresis. Here we study a minimal model of a first-order transition with an absorbing state. When the external parameter varies adiabatically the transition is indeed continuous, and we present some empirical evidence that supports this scenario. The front velocity renormalizes to zero at the extinction transition, leaving a finite “quantum” region where domain walls are stable and the desertification takes place via accumulation of local extinctions. A catastrophic regime shift may occur as a dynamical hysteresis, if the pace of environmental variations is too fast.

Weissmann, Haim; Shnerb, Nadav M.

2014-04-01

52

Wormholes in AdS  

Microsoft Academic Search

A few different examples of Euclidean wormholes with AdS asymptotics are constructed. These are geometries which are completely regular, and are solutions of ten- or eleven-dimensional supergravity. We point out that such geometries are puzzling from the AdS\\/CFT point of view, and try to speculate on possible resolutions of this puzzle. A better understanding of the physics of these geometries

Liat Maoz

2005-01-01

53

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.

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

2014-01-01

54

Adaptive Stochastic Resource Control: A Machine Learning Approach  

Microsoft Academic Search

The paper investigates stochastic resource allocation problems with scarce, reusable resources and non-preemtive, time-dependent, interconnected tasks. This approach is a natural generalization of several standard resource management problems, such as schedul- ing and transportation problems. First, reactive solutions are considered and defined as control policies of suitably reformulated Markov decision processes (MDPs). We argue that this reformulation has several favorable

Balázs Csanád Csáji; László Monostori

2008-01-01

55

A stochastic approach to the flood control problem  

Microsoft Academic Search

We propose a stochastic model in conjunction with reliability analysis concepts to improve estimates for the protection volume that should be allocated in a reservoir to control a flood wave. In this approach, the inflow that reaches the reservoir during a flood is considered to be a load, and the reservoir capacity to control this flood is considered to be

Marinho G. Andrade; M. D. Fragoso; A. A. F. M. Carneiro

2000-01-01

56

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

57

Factors influencing lysis time stochasticity in bacteriophage ?  

PubMed Central

Background Despite identical genotypes and seemingly uniform environments, stochastic gene expression and other dynamic intracellular processes can produce considerable phenotypic diversity within clonal microbes. One trait that provides a good model to explore the molecular basis of stochastic variation is the timing of host lysis by bacteriophage (phage). Results Individual lysis events of thermally-inducible ? lysogens were observed using a temperature-controlled perfusion chamber mounted on an inverted microscope. Both mean lysis time (MLT) and its associated standard deviation (SD) were estimated. Using the SD as a measure of lysis time stochasticity, we showed that lysogenic cells in controlled environments varied widely in lysis times, and that the level of lysis time stochasticity depended on allelic variation in the holin sequence, late promoter (pR') activity, and host growth rate. In general, the MLT was positively correlated with the SD. Both lower pR' activities and lower host growth rates resulted in larger SDs. Results from premature lysis, induced by adding KCN at different time points after lysogen induction, showed a negative correlation between the timing of KCN addition and lysis time stochasticity. Conclusions Taken together with results published by others, we conclude that a large fraction of ? lysis time stochasticity is the result of random events following the expression and diffusion of the holin protein. Consequently, factors influencing the timing of reaching critical holin concentrations in the cell membrane, such as holin production rate, strongly influence the mean lysis time and the lysis time stochasticity.

2011-01-01

58

Computationally efficient control allocation  

NASA Technical Reports Server (NTRS)

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

Durham, Wayne (Inventor)

2001-01-01

59

Organ allocation in lung transplant.  

PubMed

Since the first successful single-lung transplant in 1983 and double-lung transplant in 1986, thousands of patients have benefited from the procedures. Until 1995, allocation of donor lungs was based purely on time on the waiting list. In 1995, a 90-day credit was given to patients with idiopathic pulmonary fibrosis, while still maintaining allocation based on waiting list time. In 2005, the lung allocation score (LAS) was implemented, dramatically changing the way lungs are allocated. This article will explore the reasons for the creation of the LAS, the design of the score, early experience with transplant results under the new system, and further changes that may be made to the system of lung allocation. As surgical techniques and medical management evolve, so to will the management of potential donors and the allocation of their organs, with the aim of benefiting patients needing lung transplantation in the United States. PMID:17998365

Davis, Steven Q; Garrity, Edward R

2007-11-01

60

The General Yard Allocation Problem  

Microsoft Academic Search

The General Yard Allocation Problem (GYAP) is a resource allocation problem faced by the Port of Singapore Authority. Here,\\u000a space allocation for cargo is minimized for all incoming requests for space required in the yard within time intervals. The\\u000a GYAP is NP-hard for which we propose several heuristic algorithms, including Tabu Search, Simulated Annealing, Genetic Algorithms\\u000a and the recently emerged

Ping Chen; Zhaohui Fu; Andrew Lim; Brian Rodrigues

2003-01-01

61

Optimal asset allocation for pension funds under mortality risk during the accumulation and decumulation phases  

Microsoft Academic Search

In a …nancial market with one riskless asset and nrisky assets following geometric Brownian motions, we solve the problem of a pension fund max- imizing the expected CRRA utility of its terminal wealth. By considering a stochastic death time for a subscriber, we solve a unique problem for both accumulation and decumulation phases. We show that the optimal asset allocation

Paolo Battocchio; Francesco Menoncin; Olivier Scaillet

2007-01-01

62

Intelligent resource simulation for an airport check-in counter allocation system  

Microsoft Academic Search

The objective of resource allocation systems is to assign valuable corporate resources to meet business demands. However, in applications involving stochastic events, demands cannot be determined explicitly beforehand. For those applications, computer simulation is often used to predict resource demands. The paper describes research in developing a knowledge based simulation system to predict resource requirements at an international airport. Our

Hon Wai Chun; Raymond Wai Tak Mak

1999-01-01

63

CREDIT AND WOMEN'S GROUP MEMBERSHIP IN SOUTH INDIA: TESTING MODELS OF INTRAHOUSEHOLD ALLOCATIVE BEHAVIOR  

Microsoft Academic Search

This article uses empirical data from the author's own South India household survey, which compares the impact of slightly diverging credit schemes upon selected indicators of allocative behavior to test the value added of an economic institutional approach for modeling intrahousehold allocation. It is argued that the income-pooling test and conventional neoclassical household models inadequately picture what happens within households

Nathalie Holvoet

2005-01-01

64

Joint optimization of bid and budget allocation in sponsored search  

Microsoft Academic Search

This paper is concerned with the joint allocation of bid price and campaign budget in sponsored search. In this application, an advertiser can create a number of campaigns and set a budget for each of them. In a campaign, he\\/she can further create several ad groups with bid keywords and bid prices. Data analysis shows that many advertisers are dealing

Weinan Zhang; Ying Zhang; Bin Gao; Yong Yu; Xiaojie Yuan; Tie-Yan Liu

2012-01-01

65

Safety and Reliability Driven Task Allocation in Distributed Systems  

Microsoft Academic Search

Distributed computer systems are increasingly being employed for critical applications, such as aircraft control, industrial process control, and banking systems. Maximizing performance has been the conventional objective in the allocation of tasks for such systems. Inherently, distributed systems are more complex than centralized systems. The added complexity could increase the potential for system failures. Some work has been done in

S. Srinivasan; Niraj K. Jha

1999-01-01

66

Variational Bayesian Stochastic Complexity of Mixture Models  

Microsoft Academic Search

The Variational Bayesian framework has been widely used to ap- proximate the Bayesian learning. In various applications, it has provided computational tractability and good generalization per- formance. In this paper, we discuss the Variational Bayesian learn- ing of the mixture of exponential families and provide some ad- ditional theoretical support by deriving the asymptotic form of the stochastic complexity. The

Kazuho Watanabe; Sumio Watanabe

2005-01-01

67

A Study on Ad-Place Quantity Optimization in AdWords Auction  

Microsoft Academic Search

Auction is a traditional and efficient mechanism for rare resource allocation, and it is one new strategy for Internet Search Engine providers to price their AdWords as well. However, the number of AdWords places can be infinte related to an AdWords due to Internet technology. As a result, supply often exceeds demand. It is a usual phenomenon that only one

E. Zhang

2007-01-01

68

Stochastic cooling in RHIC  

SciTech Connect

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

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

2009-05-04

69

On stochastic inflation  

SciTech Connect

The purpose of this talk is to briefly review the status of the paradigm of stochastic inflation especially with regard to some fundamental issues that are still not clearly understood. Put in a nut-shell, stochastic inflation is the attempt to model infra-red quantum fluctuations in an inflationary Universe as a real-time stochastic process.

Habib, S.

1991-12-31

70

Allocation Models in Compensatory Education.  

ERIC Educational Resources Information Center

An allocation model for compensatory education was implemented in the Mesa, Arizona Public Schools based on educational need rather than on the current method of allocation which is based on economic need. Five models were developed and presented. The models incorporated, in addition to strict educational need, demographic characteristics of the…

Vicino, Frank; And Others

71

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

72

Stochastic differential equations  

SciTech Connect

This book provides a unified treatment of both regular (or random) and Ito stochastic differential equations. It focuses on solution methods, including some developed only recently. Applications are discussed, in particular an insight is given into both the mathematical structure, and the most efficient solution methods (analytical as well as numerical). Starting from basic notions and results of the theory of stochastic processes and stochastic calculus (including Ito's stochastic integral), many principal mathematical problems and results related to stochastic differential equations are expounded here for the first time. Applications treated include those relating to road vehicles, earthquake excitations and offshore structures.

Sobczyk, K. (Polska Akademia Nauk, Warsaw (Poland))

1990-01-01

73

Optimal Reactive Power Allocation  

Microsoft Academic Search

A systematic procedure is developed to locate reactive power devices in a power system based on a set of indices, that are based on overall system conditions. After identifying the desired locations, the cost of installation and number of reactive power devices, subject to any required practical and real economic constraints are minimized. Existing controllers are fully utilized before adding

A. Venkataramana; J. Carr; R. S. Ramshaw

1987-01-01

74

Resource Balancing Control Allocation  

NASA Technical Reports Server (NTRS)

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

Frost, Susan A.; Bodson, Marc

2010-01-01

75

Allocation of nursing time.  

PubMed

The purpose of this study was to examine the allocation of nursing time to various activities of registered and assistant nurses during the day shift. Twenty-three registered (RN) and eighteen assistant nurses (AN) working in medical and surgical wards of five large hospitals were studied. The findings have shown that the most frequent activities performed were; indirect care representing 35.6% of the time, direct care representing 23.8% of the time, personal activities representing 16.8% of the time, and direct nursing interventions representing 8.2% of the time. Cross-tabulation revealed that RNs provided direct care less frequently and indirect care more frequently than ANs (25.3 activities per RN and 27.5 per AN, 62.1 activities per RN and 32.6 per AN, respectively). Many indirect care activities were found to be the responsibility of the head nurse (64), secretary (465), and others (104). Less expected results were the minimal amounts of time spent on both education and research activities (1.3% and 0.0% respectively). Nurse managers have to free nurses from subsidiary work and to find mechanisms to distribute nursing valuable time more efficiently. PMID:9060782

Lemonidou, C; Plati, C; Brokalaki, H; Mantas, J; Lanara, V

1996-01-01

76

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

77

Zinc allocation and re-allocation in rice  

PubMed Central

Aims: Agronomy and breeding actively search for options to enhance cereal grain Zn density. Quantifying internal (re-)allocation of Zn as affected by soil and crop management or genotype is crucial. We present experiments supporting the development of a conceptual model of whole plant Zn allocation and re-allocation in rice. Methods: Two solution culture experiments using 70Zn applications at different times during crop development and an experiment on within-grain distribution of Zn are reported. In addition, results from two earlier published experiments are re-analyzed and re-interpreted. Results: A budget analysis showed that plant zinc accumulation during grain filling was larger than zinc allocation to the grains. Isotope data showed that zinc taken up during grain filling was only partly transported directly to the grains and partly allocated to the leaves. Zinc taken up during grain filling and allocated to the leaves replaced zinc re-allocated from leaves to grains. Within the grains, no major transport barrier was observed between vascular tissue and endosperm. At low tissue Zn concentrations, rice plants maintained concentrations of about 20 mg Zn kg?1 dry matter in leaf blades and reproductive tissues, but let Zn concentrations in stems, sheath, and roots drop below this level. When plant zinc concentrations increased, Zn levels in leaf blades and reproductive tissues only showed a moderate increase while Zn levels in stems, roots, and sheaths increased much more and in that order. Conclusions: In rice, the major barrier to enhanced zinc allocation towards grains is between stem and reproductive tissues. Enhancing root to shoot transfer will not contribute proportionally to grain zinc enhancement.

Stomph, Tjeerd Jan; Jiang, Wen; Van Der Putten, Peter E. L.; Struik, Paul C.

2014-01-01

78

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

79

Methods for Allocating Highway Costs.  

National Technical Information Service (NTIS)

Microeconomic theory and other concepts related to pricing are reviewed and applied to the problem of designing highway user charges. In view of the emphasis in the Congressional request for the Highway Cost Allocation Study on setting charges in accordan...

D. B. Lee

1981-01-01

80

The effective use of student time: A stochastic frontier production function case study  

Microsoft Academic Search

Abstract The relationship between,student study time allocation and examination,performance,is little understood. We model the allocation of student time into formal,study (lectures and classes) and self study and its relationship to university examination,scores using a stochastic frontier production,function. This case study uses unique,time budget,data and detailed personal records from one university in Spain. The results suggest that, within the formal system

Peter Dolton; Oscar D. Marcenaro; Lucia Navarro

2001-01-01

81

Conference structures and fair allocation rules  

Microsoft Academic Search

To describe how the outcome of a cooperative game might depend on which groups of players hold cooperative planning conferences, we study allocation rules, which are functions mapping conference structures to payoff allocations. An allocation rule is fair if every conference always gives equal benefits to all its members. Any characteristic function game without sidepayments has a unique fair allocation

R. B. Myerson

1980-01-01

82

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

83

Molecular Stochastics: A Study of Direct Production of Stochastic Sequences from Transducers.  

National Technical Information Service (NTIS)

Molecular Stochastics is an extension of stochastic computing. The main concern of Molecular Stochastics is the generation of stochastic sequences that are used as the encoded information in stochastic computing. Also, these stochastic sequences in order ...

J. R. Cutler

1975-01-01

84

Preserving the allocation ratio at every allocation with biased coin randomization and minimization in studies with unequal allocation.  

PubMed

The demand for unequal allocation in clinical trials is growing. Most commonly, the unequal allocation is achieved through permuted block randomization. However, other allocation procedures might be required to better approximate the allocation ratio in small samples, reduce the selection bias in open-label studies, or balance on baseline covariates. When these allocation procedures are generalized to unequal allocation, special care is to be taken to preserve the allocation ratio at every allocation step. This paper offers a way to expand the biased coin randomization to unequal allocation that preserves the allocation ratio at every allocation. The suggested expansion works with biased coin randomization that balances only on treatment group totals and with covariate-adaptive procedures that use a random biased coin element at every allocation. Balancing properties of the allocation ratio preserving biased coin randomization and minimization are described through simulations. It is demonstrated that these procedures are asymptotically protected against the shift in the rerandomization distribution identified for some examples of minimization with 1:2 allocation. The asymptotic shift in the rerandomization distribution of the difference in treatment means for an arbitrary unequal allocation procedure is explicitly derived in the paper. PMID:22161821

Kuznetsova, Olga M; Tymofyeyev, Yevgen

2012-04-13

85

Multidimensional Stochastic Approximation Methods  

Microsoft Academic Search

Multidimensional stochastic approximation schemes are presented, and conditions are given for these schemes to converge a.s. (almost surely) to the solutions of $k$ stochastic equations in $k$ unknowns and to the point where a regression function in $k$ variables achieves its maximum.

Julius R. Blum

1954-01-01

86

Almost Global Stochastic Stability  

Microsoft Academic Search

We develop a method to prove almost global stability of stochastic dierential equations in the sense that almost every initial point (with respect to the Lebesgue measure) is asymptotically attracted to the origin with unit probability. The method can be viewed as a dual to Lyapunov's second method for stochastic dierential equations and extends the deterministic result in (A. Rantzer,

Ramon van Handel

2006-01-01

87

Stochastic chaplygin systems  

NASA Astrophysics Data System (ADS)

We mimic the stochastic Hamiltonian reduction of Lazaro-Cami and Ortega [18, 19] for the case of certain nonholonomic systems with symmetries. Using the nonholonomic connection it is shown that the drift of the stochastically perturbed n-dimensional Chaplygin ball is a certain gradient of the density of the preserved measure of the deterministic system.

Hochgerner, Simon

2010-12-01

88

Adaptive Resource Allocation in Jamming Teams Using Game Theory  

Microsoft Academic Search

In this work, we study the problem of power allocation and adaptive\\u000amodulation in teams of decision makers. We consider the special case of two\\u000ateams with each team consisting of two mobile agents. Agents belonging to the\\u000asame team communicate over wireless ad hoc networks, and they try to split\\u000atheir available power between the tasks of communication and

Ali Khanafer; Sourabh Bhattacharya; Tamer Bascar

2011-01-01

89

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

90

Numerical solution of the Hamilton–Jacobi–Bellman formulation for continuous time mean variance asset allocation  

Microsoft Academic Search

We solve the optimal asset allocation problem using a mean variance approach. The original mean variance optimization problem can be embedded into a class of auxiliary stochastic linear-quadratic (LQ) problems using the method in Zhou and Li (2000) and Li and Ng (2000). We use a finite difference method with fully implicit timestepping to solve the resulting nonlinear Hamilton–Jacobi–Bellman (HJB)

J. Wang; P. A. Forsyth

2010-01-01

91

Hopfield Neural Network as a Channel Allocator  

Microsoft Academic Search

Dynamic Channel Allocation (DCA) schemes based on Artificial Neural Network (ANN) technology were seen as performing better\\u000a overall than conventional statistically based Channel Allocation!DCA Channel Allocation!DCA Channel Allocation!DCA Channel\\u000a Allocation!DCA DCA schemes. Furthermore, some papers report that within the ANN schemes adopted as Channel Allocators (CA),\\u000a the Neural Network!HNN Neural Network!HNN Neural Network!HNN Neural Network!HNN Neural Network!Hopfield Neural Network!Hopfield\\u000a Neural

Ahmed Emam; Sarhan M. Musa

92

Balanced allocation with succinct representation  

Microsoft Academic Search

Motivated by applications in guaranteed delivery in computational advertising, we consider the general problem of balanced allocation in a bipartite supply-demand setting. Our formulation captures the notion of deviation from being balanced by a convex penalty function. While this formulation admits a convex programming solution, we strive for more robust and scalable algorithms. For the case of L1 penalty functions

Saeed Alaei; Ravi Kumar; Azarakhsh Malekian; Erik Vee

2010-01-01

93

Optimal Resource Allocation in Clouds  

Microsoft Academic Search

Cloud platforms enable enterprises to lease computing power in the form of virtual machines. An important problem for such enterprise users is to understand how many and what kinds of virtual machines will be needed from clouds. We formulate demand for computing power and other resources as a resource allocation problem with multiplicity, where computations that have to be performed

Fangzhe Chang; Jennifer Ren; Ramesh Viswanathan

2010-01-01

94

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

95

Learning the task allocation game  

Microsoft Academic Search

The distributed task allocation problem occurs in domains like web services, the grid, and other distributed systems. In this problem, the system consists of servers and mediators. Servers execute tasks and may dier in their capabilities, e.g. one server may take more time than the other in ex- ecuting the same task. Mediators act on behalf of users, which can

Sherief Abdallah; Victor R. Lesser

2006-01-01

96

The Discipline of Asset Allocation.  

ERIC Educational Resources Information Center

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

Petzel, Todd E.

2000-01-01

97

Models for Railway Track Allocation  

Microsoft Academic Search

The optimal track allocation problem (OPTRA) is to find, in a given railway network, a conflict free set of train routes of maximum value. We study two types of integer programming formulations for this problem: a standard formulation that models block conflicts in terms of packing constraints, and a novel formulation of the 'extended' type that is based on additional

Ralf Borndörfer; Thomas Schlechte

2007-01-01

98

Georgia Highway Cost Allocation Study.  

National Technical Information Service (NTIS)

The purpose of the study was to allocate highway construction and maintenance costs among vehicle types for the State Highway System which is the responsibility of the State of Georgia. This was accomplished by determining an annual road user cost respons...

1979-01-01

99

Quantum Stochastic Processes  

SciTech Connect

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

Spring, William Joseph [Quantum Information and Probability Group, School of Computer Science, University of Hertfordshire, Hatfield, Herts AL10 9AB (United Kingdom)

2009-04-13

100

Elementary Stochastic Cooling.  

National Technical Information Service (NTIS)

Major headings in this review include: proton sources; antiproton production; antiproton sources and Liouville, the role of the Debuncher; transverse stochastic cooling, time domain; the accumulator; frequency domain; pickups and kickers; Fokker-Planck eq...

A. V. Tollestrup G . Dugan

1983-01-01

101

Stochastic Network Utility Maximization A tribute to Kelly's paper published in this journal a decade ago  

Microsoft Academic Search

SUMMARY Since the seminal work by Kelly on distributed network resource allocation using the language of Network Utility Maximization (NUM) a decade ago, there have been extensive research efforts generalizing and applying NUM to model, analyze, and design various network protocols and architectures. Some of these works combine the distributed optimization approach with stochastic network models to study NUM under

Yung Yi; Mung Chiang

2008-01-01

102

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.

103

Warped AdS3 black holes  

NASA Astrophysics Data System (ADS)

Three dimensional topologically massive gravity (TMG) with a negative cosmological constant -l-2 and positive Newton constant G admits an AdS3 vacuum solution for any value of the graviton mass ?. These are all known to be perturbatively unstable except at the recently explored chiral point ?l = 1. However we show herein that for every value of ?l ? 3 there are two other (potentially stable) vacuum solutions given by SL(2,Bbb R) × U(1)-invariant warped AdS3 geometries, with a timelike or spacelike U(1) isometry. Critical behavior occurs at ?l = 3, where the warping transitions from a stretching to a squashing, and there are a pair of warped solutions with a null U(1) isometry. For ?l > 3, there are known warped black hole solutions which are asymptotic to warped AdS3. We show that these black holes are discrete quotients of warped AdS3 just as BTZ black holes are discrete quotients of ordinary AdS3. Moreover new solutions of this type, relevant to any theory with warped AdS3 solutions, are exhibited. Finally we note that the black hole thermodynamics is consistent with the hypothesis that, for ?l > 3, the warped AdS3 ground state of TMG is holographically dual to a 2D boundary CFT with central charges c_R-formula and c_L-formula.

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

2009-03-01

104

Warped AdS3 black holes  

NASA Astrophysics Data System (ADS)

Three dimensional topologically massive gravity (TMG) with a negative cosmological constant -ell-2 and positive Newton constant G admits an AdS3 vacuum solution for any value of the graviton mass ?. These are all known to be perturbatively unstable except at the recently explored chiral point ?ell = 1. However we show herein that for every value of ?ell ? 3 there are two other (potentially stable) vacuum solutions given by SL(2,Bbb R) × U(1)-invariant warped AdS3 geometries, with a timelike or spacelike U(1) isometry. Critical behavior occurs at ?ell = 3, where the warping transitions from a stretching to a squashing, and there are a pair of warped solutions with a null U(1) isometry. For ?ell > 3, there are known warped black hole solutions which are asymptotic to warped AdS3. We show that these black holes are discrete quotients of warped AdS3 just as BTZ black holes are discrete quotients of ordinary AdS3. Moreover new solutions of this type, relevant to any theory with warped AdS3 solutions, are exhibited. Finally we note that the black hole thermodynamics is consistent with the hypothesis that, for ?ell > 3, the warped AdS3 ground state of TMG is holographically dual to a 2D boundary CFT with central charges c_R-formula and c_L-formula.

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

2009-03-01

105

24 CFR 594.15 - Allocation amounts.  

Code of Federal Regulations, 2013 CFR

...ASSISTANT SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT COMMUNITY FACILITIES JOHN HEINZ NEIGHBORHOOD DEVELOPMENT PROGRAM Funding Allocation and Criteria § 594.15 Allocation amounts. (a)...

2013-04-01

106

39 CFR 3060.12 - Asset allocation.  

Code of Federal Regulations, 2010 CFR

...Service 1 2010-07-01 2010-07-01 false Asset allocation. 3060.12 Section 3060.12 Postal Service...THEORETICAL COMPETITIVE PRODUCTS ENTERPRISE § 3060.12 Asset allocation. Within 6 months of January 23, 2009,...

2010-07-01

107

39 CFR 3060.12 - Asset allocation.  

Code of Federal Regulations, 2010 CFR

...Service 1 2009-07-01 2009-07-01 false Asset allocation. 3060.12 Section 3060.12 Postal Service...THEORETICAL COMPETITIVE PRODUCTS ENTERPRISE § 3060.12 Asset allocation. Within 6 months of January 23, 2009,...

2009-07-01

108

50 CFR 660.55 - Allocations.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Allocations. 660.55 Section 660.55 Wildlife and Fisheries FISHERY CONSERVATION...WEST COAST STATES West Coast Groundfish Fisheries § 660.55 Allocations. (a) General....

2013-10-01

109

Review of Highway Cost Allocation Methodologies.  

National Technical Information Service (NTIS)

The objectives of the current cost allocation study, the fifth in a series begun in 1982, include the following: (1) to evaluate current cost allocation methodologies and identify possible changes to Kentucky practices; and (2) to determine the 1991 fisca...

J. A. Deacon J. G. Pigman N. Stamatiadis

1992-01-01

110

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

111

A master production scheduling procedure for stochastic demand and rolling planning horizons  

Microsoft Academic Search

The problem of interest is a one product, uncapacitated master production schedule (MPS) in which decisions are made under rolling planning horizons. Demand is stochastic and time varying, and effectiveness is measured by inventory holding, production setup, and backorder costs.Typically, in both the research literature and the business practice the stochastic nature of the problem is modeled in an ad

Vicente Vargas; Richard Metters

2011-01-01

112

Decentralized, Adaptive Resource Allocation for Sensor Networks  

Microsoft Academic Search

This paper addresses the problem of resource allocation in sensor networks. We are concerned with how to allocate limited energy, radio bandwidth, and other resources to maximize the value of each node's contribution to the network. Sensor networks present a novel resource allocation challenge: given extremely limited re- sources, varying node capabilities, and changing network condi- tions, how can one

Geoffrey Mainland; David C. Parkes; Matt Welsh

2005-01-01

113

Register Allocation via Hierarchical Graph Coloring  

Microsoft Academic Search

We present a graph coloring register allocator de- signed to minimize the number of dynamic memory references. We cover the program with sets of blocks called tiles and group these tiles into a tree reflecting the program's hierarchical control structure. Registers are allocated for each tile using standard graph coloring techniques and the local allocation and conflict information is passed

David Callahan; Brian Koblenz

1991-01-01

114

Auction-based effective bandwidth allocation mechanism  

Microsoft Academic Search

A bandwidth allocation system is proposed by using GVA (Generalized Vickrey Auction), which can be used for leasing lines, reselling lines, or allocating bandwidth to individual users. In the proposed system, network resources, which are composed of many links at various bandwidths, are regarded as multiple units. The application of GVA protocol to bandwidth allocation among multiple users is also

Eiji TAKAHASHI; Y. Tanaka

2003-01-01

115

Linking Total Catch Quotas and Allocation Schemes  

Microsoft Academic Search

Fishery managers are faced with many options when setting the total catch quota for a fishery and allocating the catch among user groups. In many fisheries, these management issues are approached independently, and allocations are assigned after the total catch quota has been determined. Because allocations determine not just the yields to the different user groups but also characteristics of

Christopher M. Legault

1998-01-01

116

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

PubMed Central

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

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

2012-01-01

117

A soliton menagerie in AdS  

NASA Astrophysics Data System (ADS)

We explore the behaviour of charged scalar solitons in asymptotically global AdS4 spacetimes. This is motivated in part by attempting to identify under what circumstances such objects can become large relative to the AdS length scale. We demonstrate that such solitons generically do get large and in fact in the planar limit smoothly connect up with the zero temperature limit of planar scalar hair black holes. In particular, for given Lagrangian parameters we encounter multiple branches of solitons: some which are perturbatively connected to the AdS vacuum and surprisingly, some which are not. We explore the phase space of solutions by tuning the charge of the scalar field and changing scalar boundary conditions at AdS asymptopia, finding intriguing critical behaviour as a function of these parameters. We demonstrate these features not only for phenomenologically motivated gravitational Abelian-Higgs models, but also for models that can be consistently embedded into eleven dimensional supergravity.

Gentle, Simon A.; Rangamani, Mukund; Withers, Benjamin

2012-05-01

118

What drives AdS spacetime unstable?  

NASA Astrophysics Data System (ADS)

We calculate the spectrum of linear perturbations of standing wave solutions discussed in [Phys. Rev. D 87, 123006 (2013)] as the first step of investigating the stability of the globally regular, asymptotically anti-de Sitter (AdS), time-periodic solutions discovered in [Phys. Rev. Lett. 111, 051102 (2013)]. We show that while this spectrum is only asymptotically nondispersive (as contrasted with the pure AdS case), putting a small standing wave solution on top of an AdS solution indeed prevents the turbulent instability. Thus we support the idea advocated in previous works that the nondispersive character of the spectrum of linear perturbations of AdS space is crucial for the conjectured turbulent instability.

Maliborski, Maciej; Rostworowski, Andrzej

2014-06-01

119

Communication Patterns and Allocation Strategies  

Microsoft Academic Search

Motivated by observations about job runtimes on the CPlant system, we use a trace-driven microsimulator to be- gin characterizing the performance of different classes of allocation algorithms on jobs with different communicatio n patterns in space-shared parallel systems with mesh topol- ogy. We show that relative performance varies considerably with communication pattern. The Paging strategy using the Hilbert space-filling curve

David P. Bunde; Vitus J. Leung; Jens Mache

2004-01-01

120

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.

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

2012-01-01

121

A Testbed and Methodology for Experimental Evaluation of Wireless Mobile Ad hoc Networks  

Microsoft Academic Search

Wireless mobile ad hoc network experimentation is sub- jected to stochastic factors from the radio environment and node mobility. To achieve test repeatability and result re- producibility such stochastic factors need to be controlled or assessed in order to obtain conclusive results. This has implications on the design of testbeds. We present a method- ology that addresses repeatability and describe

Erik Nordström; Per Gunningberg; Henrik Lundgren

2005-01-01

122

Stochastic quantum gravitational inflation  

NASA Astrophysics Data System (ADS)

During inflation explicit perturbative computations of quantum field theories which contain massless, nonconformal fields exhibit secular effects that grow as powers of the logarithm of the inflationary scale factor. Starobinski?'s technique of stochastic inflation not only reproduces the leading infrared logarithms at each order in perturbation theory, it can sometimes be summed to reveal what happens when inflation has proceeded so long that the large logarithms overwhelm even very small coupling constants. It is thus a cosmological analogue of what the renormalization group does for the ultraviolet logarithms of quantum field theory, and generalizing this technique to quantum gravity is a problem of great importance. There are two significant differences between gravity and the scalar models for which stochastic formulations have so far been given: derivative interactions and the presence of constrained fields. We use explicit perturbative computations in two simple scalar models to infer a set of rules for stochastically formulating theories with these features.

Tsamis, N. C.; Woodard, R. P.

2005-09-01

123

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

124

Stochastic optical active rheology  

PubMed Central

We demonstrate a stochastic based method for performing active rheology using optical tweezers. By monitoring the displacement of an embedded particle in response to stochastic optical forces, a rapid estimate of the frequency dependent shear moduli of a sample is achieved in the range of 10?1–103?Hz. We utilize the method to probe linear viscoelastic properties of hydrogels at varied cross-linker concentrations. Combined with fluorescence imaging, our method demonstrates non-linear changes of bond strength between T cell receptors and an antigenic peptide due to force-induced cell activation.

Lee, Hyungsuk; Shin, Yongdae; Kim, Sun Taek; Reinherz, Ellis L.; Lang, Matthew J.

2012-01-01

125

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

126

Stochastic description of delayed systems.  

PubMed

We study general stochastic birth and death processes including delay. We develop several approaches for the analytical treatment of these non-Markovian systems, valid, not only for constant delays, but also for stochastic delays with arbitrary probability distributions. The interplay between stochasticity and delay and, in particular, the effects of delay in the fluctuations and time correlations are discussed. PMID:23960216

Lafuerza, L F; Toral, R

2013-09-28

127

AdS in Warped Spacetimes  

Microsoft Academic Search

We obtain a large class of AdS spacetimes warped with certain internal spaces\\u000ain eleven-dimensional and type IIA\\/IIB supergravities. The warp factors depend\\u000aonly on the internal coordinates. These solutions arise as the near-horizon\\u000ageometries of more general semi-localised multi-intersections of $p$-branes. We\\u000aachieve this by noting that any sphere (or AdS spacetime) of dimension greater\\u000athan 3 can be

M. Cvetiÿc; H. Lu; C. N. Pope; J. F. Vazquez-Poritz

2000-01-01

128

Stochastic decentralized systems  

NASA Astrophysics Data System (ADS)

Fundamental aspects of decentralized systems are considered from a control perspective. The stochastic framework afforded by Markov systems is presented as a formal setting in which to study decentralized systems. A stochastic algebra is introduced which allows Markov systems to be considered in matrix format but also strikes an important connection to the classic linear system originally studied by Kalman [1960]. The process of decentralization is shown to impose constraints on observability and controllability of a system. However, it is argued that communicating decentralized controllers can implement any control law possible with a centralized controller. Communication is shown to serve a dual role, both enabling sensor data to be shared and actions to be coordinated. The viabilities of these two types of communication are tested on a real network of mobile robots where they are found to be successful at a variety of tasks. Action coordination is reframed as a decentralized decision making process whereupon stochastic cellular automata (SCA) are introduced as a model. Through studies of SCA it is found that coordination in a group of arbitrarily and sparsely connected agents is possible using simple rules. The resulting stochastic mechanism may be immediately used as a practical decentralized decision making tool (it is tested on a group of mobile robots) but, it furthermore provides insight into the general features of self-organizing systems.

Barfoot, Timothy David

129

Stochasticity in Relativistic Cosmology.  

National Technical Information Service (NTIS)

It was shown earlier by I.M. Lifshitz and two of us that the evolution of the relativistic cosmological models towards the singularity undergoes spontaneous stochastization (JETP 59, 322(1970)). In the present paper it is shown that the statistical parame...

I. M. Khalatnikov E. M. Lifshitz K. M. Khanin L. N. Shchur Y. G. Sinai

1984-01-01

130

Convex stochastic control problems  

Microsoft Academic Search

The solution of the infinite horizon stochastic control problem under certain criteria, the functional characterization and computation of optimal values and policies, is related to two dynamic programming-like functional equations: the discounted cost optimality equation (DCOE) and the average cost optimality equation (ACOE). The authors consider what useful properties, shared by large and important problem classes, can be used to

Emmanuel Ferndndez-Gaucherand; Aristotle Arapostathis; Steven I. Marcus

1992-01-01

131

Elementary stochastic cooling  

SciTech Connect

Major headings in this review include: proton sources; antiproton production; antiproton sources and Liouville, the role of the Debuncher; transverse stochastic cooling, time domain; the accumulator; frequency domain; pickups and kickers; Fokker-Planck equation; calculation of constants in the Fokker-Planck equation; and beam feedback. (GHT)

Tollestrup, A.V.; Dugan, G

1983-12-01

132

Isotropic Stochastic Flows  

Microsoft Academic Search

We consider isotropic stochastic flows in a Euclidean space of $d$ dimensions, $d \\\\geq 2$. The tendency of two-point distances and of tangent vectors to shrink or expand is related to the dimension and the proportion of the flow that is solenoidal or potential. Tangent vectors from the same point tend to become aligned in the same or opposite directions.

Peter Baxendale; Theodore E. Harris

1986-01-01

133

Stochastic Games. I. Foundations.  

National Technical Information Service (NTIS)

This paper strives to provide a sound underpinning for the theory of stochastic games. Section 2 is a reworking of the Bewley-Kohlberg result integrated with Shapley's; the black magic of Tarski's principle is replaced by the gray magic of the Hilbert Nul...

C. A. Monash

1982-01-01

134

Stochastic Programming: A Survey.  

National Technical Information Service (NTIS)

The work provides an organization and summary of the major results in the field of stochastic (or probabilistic) programming. The purpose of the work is to give an overview of the field and references for those who wish to investigate further. Initially, ...

C. E. McQuillan

1969-01-01

135

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

136

Composing High-Performance Memory Allocators  

Microsoft Academic Search

Current general-purpose memory allocators do not provide suffi- cient speed or flexibility for modern high-performance applications. Highly-tuned general purpose allocators have per-operation costs around one hundred cycles, while the cost of an operation in a cus- tom memory allocator can be just a handful of cycles. To achieve high performance, programmers often write custom memory allo- cators from scratch -

Emery D. Berger; Benjamin G. Zorn; Kathryn S. McKinley

2001-01-01

137

Indexation des allocations chomage et chomage  

Microsoft Academic Search

Nous etudions les consequences de l'indexation de l'assurance chomage sur le dernier salaire recu dans un modele de negociations salariales. Nous montrons que la hausse de l'allocation d'assurance chomage peut diminuer le taux de chomage si les travailleurs sont suffisammnet averses au risque. D'autre part, le remplacement d'une allocation d'assurance chomage par une allocation analogue, mais qui ne serait plus

E. Lehmann

1997-01-01

138

AdS Backgrounds from Asymmetric Orientifolds.  

National Technical Information Service (NTIS)

I present asymmetric orientifold models that, with the addition of RR fluxes, fix all the NS NS moduli including the dilaton. In critical string theory, this gives new AdS backgrounds with (discretely tunably) weak string coupling. Extrapolating to super-...

E. M. Silverstein

2001-01-01

139

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

140

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

141

AdS spacetime in warped spacetimes  

SciTech Connect

We obtain a large class of AdS spacetimes warped with certain internal spaces in 11-dimensional and type IIA or IIB supergravities. The warp factors depend only on the internal coordinates. These solutions arise as the near-horizon geometries of more general semilocalized multi-intersections of p-branes. We achieve this by noting that any sphere (or AdS spacetime) of dimension greater than 3 can be viewed as a foliation involving S{sup 3} (or AdS{sub 3}). Then the S{sup 3} (or AdS{sub 3}) can be replaced by a three-dimensional lens space (or a BTZ black hole), which arises naturally from the introduction of a NUT (or a pp wave) to the M-branes or the D3-brane. We then obtain multi-intersections by performing a Kaluza-Klein reduction or Hopf T-duality transformation on the fiber coordinate of the lens space (or the BTZ black hole). These geometries provide further possible examples of the AdS/CFT correspondence and of consistent embeddings of lower-dimensional gauged supergravities in D=11 or D=10.

Cvetic, M.; Lu'', H.; Pope, C. N.; Vazquez-Poritz, J. F.

2000-12-15

142

Interpolating from AdS D-2 × S2 to AdS D  

NASA Astrophysics Data System (ADS)

We investigate a large class of supersymmetric magnetic brane solutions supported by U(1) gauge fields in AdS gauged supergravities. We obtain first-order equations in terms of a superpotential. In particular, we find systems which interpolate between AdS D-2×? 2 (where ? 2=S 2 or H2) at the horizon and AdS D-type geometry in the asymptotic region, for 4? D?7. The boundary geometry of the AdS D-type metric is Minkowski D-3×? 2. This provides smooth supergravity solutions for which the boundary of the AdS spacetime compactifies spontaneously. These solutions indicate the existence of a large class of superconformal field theories in diverse dimensions whose renormalization group flow runs from the UV to the IR fixed-point. We show that the same set of first-order equations also admits solutions which are asymptotically AdS D-2×? 2 but singular at small distance. This implies that the stationary AdS D-2×? 2 solutions typically lie on the inflection points of the modulus space.

Cucu, S.; Lü, H.; Vázquez-Poritz, J. F.

2004-01-01

143

Energetics of stochastic resonance.  

PubMed

In this paper, we discuss the motion of a Brownian particle in a double-well potential driven by a periodic force in terms of energies delivered by the periodic and the noise forces and energy dissipated into the viscous environment. It is shown that, while the power delivered by the periodic force to the Brownian particle is controlled by the strength of the noise, the power delivered by the noise itself is independent of the amplitude and frequency of the periodic force. The implications of this result for the mechanism of stochastic resonance in an equilibrium system is that it is not energy from the noise force which enhances a small periodic force, but rather an increase of energy delivered by the periodic force, regulated by the strength of the noise. We further re-evaluate the frequency dependence of stochastic resonance in terms of energetic terms including efficiency. PMID:22225390

Jung, Peter; Marchesoni, Fabio

2011-12-01

144

STOCHASTIC COOLING FOR RHIC.  

SciTech Connect

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

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

2003-05-12

145

Stochastic speculative price.  

PubMed

Because a commodity like wheat can be carried forward from one period to the next, speculative arbitrage serves to link its prices at different points of time. Since, however, the size of the harvest depends on complicated probability processes impossible to forecast with certainty, the minimal model for understanding market behavior must involve stochastic processes. The present study, on the basis of the axiom that it is the expected rather than the known-for-certain prices which enter into all arbitrage relations and carryover decisions, determines the behavior of price as the solution to a stochastic-dynamic-programming problem. The resulting stationary time series possesses an ergodic state and normative properties like those often observed for real-world bourses. PMID:16591903

Samuelson, P A

1971-02-01

146

Nonparametric Stochastic Volatility  

Microsoft Academic Search

Using recent advances in the nonparametric estimation of continuous-time processes under mild statistical assumptions as well as recent developments on nonparametric volatility estimation by virtue of market microstructure noise-contaminated high-frequency asset price data, we provide (i) a theory of spot variance estimation and (ii) functional methods for stochastic volatility modelling. Our methods allow for the joint evaluation of return and

Federico M. Bandi; Roberto Reno

2009-01-01

147

Transport near stochastic threshold  

SciTech Connect

Transport in a magnetic field configuration near stochastic threshold is investigated. The waiting time distribution near magnetic islands, and the size distribution of these islands are identified as the two fundamental functions which determine both the short time subdiffusive behavior, and the regular diffusive regime. These time and length distributions are studied, the mean square displacement is expressed in terms of these functions, and the result is compared to direct numerical simulation.

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

1992-12-01

148

Stochastic Networked Computation  

Microsoft Academic Search

In this paper, the stochastic networked computation (SNC) paradigm for designing robust and energy-efficient systems-on-a-chip in nanoscale process technologies, where robust computation is treated as a statistical estimation problem is presented. The benefits of SNC are demonstrated by employing it to design an energy-efficient and robust pseudonoise-code acquisition system for the wireless CDMA2000 standard (http:\\/\\/www.3gpp2.org). Simulations in IBM's 130-nm CMOS

Girish Vishnu Varatkar; Shrikanth S. Narayanan; Naresh R. Shanbhag; Douglas L. Jones

2010-01-01

149

Entropy of stochastic flows  

NASA Astrophysics Data System (ADS)

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 \\mathbb 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.

2010-06-01

150

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

151

Remarks on stochastic resonance  

Microsoft Academic Search

A recent and interesting experimental paper [B. McNamara, K. Wiesenfeld, and R. Roy, Phys. Rev. Lett. 60, 2626 (1988)] has refocused attention on the problem of stochastic resonance by presenting measurements of the singal-to-noise ratio (SNR) of a noise driven, periodically modulated bistable ring laser. We point out that the theoretical SNR, as defined in this and a previous work,

G. Debnath; T. Zhou; Frank Moss

1989-01-01

152

On the AdS stability problem  

NASA Astrophysics Data System (ADS)

We discuss the notion of stability and the choice of boundary conditions for AdS-type space-times and point out difficulties in the construction of Cauchy data which arise if reflective boundary conditions are imposed.

Friedrich, Helmut

2014-05-01

153

Register allocation by priority-based coloring  

Microsoft Academic Search

The classic problem of global register allocation is treated in a heuristic and practical manner by adopting the notion of priorities in node-coloring. The assignment of priorities is based on estimates of the benefits that can be derived from allocating individual quantities in registers. Using the priorities, the exponential coloring process can be made to run in linear time. Since

Frederick Chow; John L. Hennessy

1984-01-01

154

Projected 1999-2000 Cost Allocation Summary.  

ERIC Educational Resources Information Center

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

Wisconsin Technical Coll. System Board, Madison.

155

Frequency allocations accommodate new commercial applications  

Microsoft Academic Search

An overview is presented of the 1992 World Administrative Radio Frequency Conference whose principal responsibility is to review and update the International Radio Regulations, including the International Table of Frequency Allocations and the procedures for utilizing the allocations. Consideration is given to the earth exploration-satellite service, the space research space operation, general-satellite service, and wind profiler radar. Attention is given

Martin R. Stiglitz; Christine Blanchard

1992-01-01

156

A Modular Algorithm for Resource Allocation  

Microsoft Academic Search

Summary. This paper concerns resource allocation in dis- tributed message passing systems, i.e., the scheduling of accesses to exclusive system resources shared among con- current processes. An efficient modular resource allocation algorithm is presented that uses any arbitrary resource al- location algorithm as a subroutine. It improves the perfor- mance of the subroutine by letting each process wait only for

Injong Rhee

1998-01-01

157

Rethinking Reinforcement: Allocation, Induction, and Contingency  

ERIC Educational Resources Information Center

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

Baum, William M.

2012-01-01

158

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

159

Optimal disk allocation for partial match queries  

Microsoft Academic Search

The problem of disk allocation addresses the issue of how to distribute a file on several disks in order to maximize concurrent disk accesses in response to a partial match query. In this paper a coding-theoretic analysis of this problem is presented, and both necessary and sufficient conditions for the existence of strictly optimal allocation methods are provided. Based on

Khaled A. S. Abdel-Ghaffar; Amr El Abbadi

1993-01-01

160

Decentralized resource allocation for road passenger transportation?  

Microsoft Academic Search

Inter-urban road passenger transportation requires the al- location of drivers and buses to transport people. In such allocation process, several constraints on driving time are being imposed by the governments in order to assure citizens safety. Such constraints, how- ever, are posing a lot of di-culties to the allocation process, usually generated by human operators. In this paper we formalize

Beatriz Lopez; Pere Urra

161

Auctions for task allocation to robots  

Microsoft Academic Search

We present an auction-based method for dynamic allocation of tasks to robots. The robots operate in a 2D environment for which they have a map. Tasks are locations in the map that have to be visited by the robots, in any order. Unexpected obstacles and other delays may prevent a robot from completing its allocated tasks. Therefore tasks not yet

Maitreyi Nanjanath; Maria Gini

2006-01-01

162

Adaptive resource allocation for efficient patient scheduling  

Microsoft Academic Search

Objective: Efficient scheduling of patient appointments on expensive resources is a complex and dynamic task. A resource is typically used by several patient groups. To service these groups, resource capacity is often allocated per group, explicitly or implicitly. Importantly, due to fluctuations in demand, for the most efficient use of resources this allocation must be flexible. Methods: We present an

Ivan B. Vermeulen; Sander M. Bohte; Sylvia G. Elkhuizen; Han Lameris; Piet J. M. Bakker; Han La Poutré

2009-01-01

163

Inferential Aspects of Adaptive Allocation Rules.  

ERIC Educational Resources Information Center

In clinical trials, adaptive allocation means that the therapies assigned to the next patient or patients depend on the results obtained thus far in the trial. Although many adaptive allocation procedures have been proposed for clinical trials, few have actually used adaptive assignment, largely because classical frequentist measures of inference…

Berry, Donald A.

164

Eternal Black Holes in AdS  

Microsoft Academic Search

We propose a dual non-perturbative description for maximally extended\\u000aSchwarzschild Anti-de-Sitter spacetimes. The description involves two copies of\\u000athe conformal field theory associated to the AdS spacetime and an initial\\u000aentangled state. In this context we also discuss a version of the information\\u000aloss paradox and its resolution.

Juan M. Maldacena

2001-01-01

165

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

166

In search for a possible statistical basis of Stochastic Resonance  

NASA Astrophysics Data System (ADS)

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

Bezrukov, Sergey M.; Vodyanoy, Igor

2000-03-01

167

12 CFR 327.53 - Allocation and payment of dividends.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Allocation and payment of dividends. 327.53 Section 327.53 Banks...POLICY ASSESSMENTS Implementation of Dividend Requirements § 327.53 Allocation and payment of dividends. (a)(1) The allocation of...

2009-01-01

168

12 CFR 327.53 - Allocation and payment of dividends.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Allocation and payment of dividends. 327.53 Section 327.53 Banks...POLICY ASSESSMENTS Implementation of Dividend Requirements § 327.53 Allocation and payment of dividends. (a)(1) The allocation of...

2010-01-01

169

49 CFR 93.1 - Issuance of aircraft allocations.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

170

On Stochastic Context-Free Languages.  

National Technical Information Service (NTIS)

In the report, normalized stochastic grammars (nsg) and stochastic pushdown automata (spda) are defined. Based on the concept of nsg, procedures for constructing the Chomsky and Greibach normal forms for normalized stochastic context-free grammars (nscfg)...

T. Huang K. S. Fu

1970-01-01

171

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.

172

Shift-invariant target in allocation problems.  

PubMed

We provide a template for finding target allocation proportions in optimal allocation designs where the target will be invariant for both shifts in location and scale of the response distributions. One possible application of such target allocation proportions is to carry out a response-adaptive allocation. While most of the existing designs are invariant for any change in scale of the underlying distributions, they are not location invariant in most of the cases. First, we indicate this serious flaw in the existing literature and illustrate how this lack of location invariance makes the performance of the designs very poor in terms of allocation for any drastic change in location, such as the changes from degrees centigrade to degrees Fahrenheit. We illustrate that unless a target allocation is location invariant, it might lead to a completely irrelevant and useless target for allocation. Then we discuss how such location invariance can be achieved for general continuous responses. We illustrate the proposed method using some real clinical trial data. We also indicate the possible extension of the procedure for more than two treatments at hand and in the presence of covariates. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24549681

Mandal, Saumen; Biswas, Atanu

2014-07-10

173

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.

174

AdS null deformations with inhomogeneities  

NASA Astrophysics Data System (ADS)

We study AdS×X null deformations arising as near horizon limits of D3-brane analogs of inhomogeneous plane waves. Restricting to normalizable deformations for the AdS5 case, these generically correspond in the dual field theory to super Yang-Mills states with light cone momentum density T++ varying spatially, the homogeneous case studied in [K. Narayan, arXiv:1202.5935] corresponding to uniform T++. All of these preserve some supersymmetry. Generically these inhomogeneous solutions exhibit analogs of horizons in the interior where a timelike Killing vector becomes null. From the point of view of x+-dimensional reduction, the circle pinches off on these horizon loci in the interior. We discuss similar inhomogeneous solutions with asymptotically Lifshitz boundary conditions, as well as aspects of Lifshitz singularities in string constructions involving anti-de Sitter null deformations. We also briefly discuss holographic entanglement entropy for some of these.

Narayan, K.

2012-12-01

175

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

176

Diffusion with Stochastic Resetting  

NASA Astrophysics Data System (ADS)

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

Evans, Martin R.; Majumdar, Satya N.

2011-04-01

177

Allocation models for DMUs with negative data  

NASA Astrophysics Data System (ADS)

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

Tohidi, Ghasem; Khodadadi, Maryam

2013-06-01

178

The allocation of the radio spectrum  

NASA Astrophysics Data System (ADS)

The system of the radio spectrum (10 kHz-300 GHz) allocation is discussed in its technical, economic, and managerial aspects. Possible improvements to the system are considered, such as minimizing human management, establishing a single authority for the allocation of the spectrum, and stimulating a more efficient use of the spectrum with economic incentives. The 'anarchy band' concept, a system of dynamic allocation, is suggested as a means of replacing human management with electronic equipment. The growing importance of the satellite portion of the spectrum is also shown.

Jackson, C. L.

1980-02-01

179

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

180

SBI allocation between heavy and singlet missiles  

SciTech Connect

The optimal allocation of space-based interceptors (SBIs) between fixed, heavy missiles and mobile singlets can be derived from approximate expressions for the boost-phase penetration of each. Singlets can cluster before launch and have shorter burn times, which reduce their availability to SBIs by an order of magnitude. Singlet penetration decreased slowly with the number of SBIs allocated to them; heavy missile penetration falls rapidly. The allocation to the heavy missiles falls linearly with their number. The penetration of heavy and singlet missiles is proportional to their numbers and inversely proportional to their availability. 8 refs., 2 figs.

Canavan, G.H.

1991-04-01

181

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

182

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

183

Google The ADS  

NASA Astrophysics Data System (ADS)

The ADS provides a search system for over 4.8 million records in Astronomy, Planetary Sciences, and Physics and 3.3 million scanned pages of the scholarly literature. In order to improve access to the ADS and to make searching easier, we allow Google to index the information in the ADS. Since many scientists use Google as their general search system, it makes it easier to also search the scientific literature that the ADS covers. HOWEVER, please be aware that Google does not index all the abstracts in the ADS. Their system crawls the ADS, but may miss some abstracts on a random basis. We therefore recommend for detailed searches to continue using the ADS search system directly. Since a one-field search system like Google seems to be popular, the ADS has developed such an interface to the ADS as well. The new interface allows you to specify word and author searches in one input field. Author names are detected automatically in the input. Years and year ranges are detected as well. This new interface is available on the ADS homepage or at: http://adsabs.harvard.edu/quick_service.html

Eichhorn, Guenther; Accomazzi, A.; Grant, C. S.; Henneken, E.; Kurtz, M. J.; Thompson, D. M.; Murray, S. S.

2006-09-01

184

Computer rendering of stochastic models  

Microsoft Academic Search

A recurrent problem in generating realistic pictures by computers is to represent natural irregular objects and phenomena without undue time or space overhead. We develop a new and powerful solution to this computer graphics problem by modeling objects as sample paths of stochastic processes. Of particular interest are those stochastic processes which previously have been found to be useful models

Alain Fournier; Donald S. Fussell; Loren C. Carpenter

1982-01-01

185

Distribution sensitivity in stochastic programming  

Microsoft Academic Search

In this paper, stochastic programming problems are viewed as parametric programs with respect to the probability distributions of the random coefficients. General results on quantitative stability in parametric optimization are used to study distribution sensitivity of stochastic programs. For recourse and chance constrained models quantitative continuity results for optimal values and optimal solution sets are proved (with respect to suitable

Werner Römisch; Riidiger Schultz

1991-01-01

186

Asymptotic analysis of stochastic programs  

Microsoft Academic Search

In this paper we discuss a general approach to studying asymptotic properties of statistical estimators in stochastic programming. The approach is based on an extended delta method and appears to be particularly suitable for deriving asymptotics of the optimal value of stochastic programs. Asymptotic analysis of the optimal value will be presented in detail. Asymptotic properties of the corresponding optimal

Alexander Shapiro

1991-01-01

187

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

188

Stochastic power flow modeling  

SciTech Connect

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

Not Available

1980-06-01

189

Behavioral Stochastic Resonance  

NASA Astrophysics Data System (ADS)

Zooplankton emit weak electric fields into the surrounding water that originate from their own muscular activities associated with swimming and feeding. Juvenile paddlefish prey upon single zooplankton by detecting and tracking these weak electric signatures. The passive electric sense in the fish is provided by an elaborate array of electroreceptors, Ampullae Lorenzini, spread over the surface of an elongated rostrum. We have previously shown that the fish use stochastic resonance to enhance prey capture near the detection threshold of their sensory system. But stochastic resonance requires an external source of electrical noise in order to function. The required noise can be provided by a swarm of plankton, for example Daphnia. Thus juvenile paddlefish can detect and attack single Daphnia as outliers in the vicinity of the swarm by making use of noise from the swarm itself. From the power spectral density of the noise plus the weak signal from a single Daphnia we calculate the signal-to-noise ratio and the Fisher information at the surface of the paddlefish's rostrum. The results predict a specific attack pattern for the paddlefish that appears to be experimentally testable.

Freund, Jan A.; Schimansky-Geier, Lutz; Beisner, Beatrix; Neiman, Alexander; Russell, David F.; Yakusheva, Tatyana; Moss, Frank

2001-03-01

190

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

191

Comparative Study in the Reliability Allocation Process.  

National Technical Information Service (NTIS)

The purpose of the report was to investigate the differences in system reliability and system cost in the reliability allocation process between an independent assumption among operating components of an active-parallel-exponential system and a dependent ...

T. D. Cox

1972-01-01

192

Statistical bandwidth allocation for multiservice networks  

NASA Astrophysics Data System (ADS)

Multiservice networks will carry different kinds of applications in the near future. Bandwidth requirements change rapidly, and the network resource management will play an important role to guarantee the use of the limited resources in the most efficient way. We approach the channel capacity allocation problem by developing an SLA (Service Level Agreement) based channel allocation method. In our model, the channel may be wired or wireless, so this method can be adapted in multi-technique networks. The algorithm allocates resources to several different service classes via several different capacity routes. Service provider perfroms optimization by allocating data rate in such a way that the satisfactory of the customers as well as the revenue is maximized.

Hamalainen, Timo; Joutsensalo, Jyrki

2002-09-01

193

Transportation Finance, Equity, and Cost Allocation.  

National Technical Information Service (NTIS)

The four (4) papers in this report deal with the following areas: recent advances in highway cost allocation analysis; proposed fare policy for advance-reservation bus service; income equity of two transit funding sources; and economic analysis of transpo...

D. B. Lee R. P. Warren A. D. Rogers J. Collura R. Beliveau

1981-01-01

194

42 CFR 24.2 - Allocation.  

Code of Federal Regulations, 2013 CFR

...2 Section 24.2 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES PERSONNEL SENIOR BIOMEDICAL RESEARCH SERVICE § 24.2 Allocation. (a) The Secretary, within the number authorized in the PHS Act,...

2013-10-01

195

48 CFR 5452.249 - Allocation.  

Code of Federal Regulations, 2013 CFR

... 2012-10-01 true 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...

2013-10-01

196

Genetically Engineered Food AD  

NSDL National Science Digital Library

How has biotechnology been used to improve the quality of food available today? Students are placed in groups of 2 to create an advertisement for a genetically engineered food and are then asked to present their ad. The ads are created with small poster board or paper, markers, and construction paper. Students also use the computer for lettering and clip art. If enough computers and suitable software was available, the ads could be completely done on the computer.

Lana Hays (Saint Henry District High School REV)

2005-04-11

197

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

198

Memory management unit with dynamic page allocation  

US Patent & Trademark Office Database

A memory management unit (MMU 12, FIG. 1) is provided which allocates space in a memory unit (2, FIG. 1) to a number of user tasks being performed concurrently by a CPU (5, FIG. 1). The MMU is capable of dynamically changing the number of concurrent user tasks and the page allocation for each task. The MMU also allows direct memory accesses into the address space of any user task.

1989-02-14

199

Optimality versus stability in water resource allocation.  

PubMed

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

Read, Laura; Madani, Kaveh; Inanloo, Bahareh

2014-01-15

200

The Fault-Tolerant Facility Allocation Problem  

Microsoft Academic Search

We study the problem of Fault-Tolerant Facility Allocation (FTFA) which is a relaxation of the classical Fault-Tolerant Facility Location (FTFL) problem [1]. Given a set of sites, a set of cities, and corresponding facility operating cost at each site as well as connection\\u000a cost for each site-city pair, FTFA requires to allocate each site a proper number of facilities and

Shihong Xu; Hong Shen

2009-01-01

201

Optimal food allocation in a slave economy  

Microsoft Academic Search

.   We propose a model of food allocation in an economy in which property rights exist in human beings. We assume that a slave-owner\\u000a allocates food over the slave's lifetime so as to maximise his own wealth. The slave's productive capacity is determined endogenously\\u000a by food consumption. Food allotment during childhood and adolescence determines productive capacity over the life course.

R. Rees; John Komlos; Ngo V. Long; Ulrich Woitek

2003-01-01

202

Channel Allocation for GPRS with Buffering Mechanisms  

Microsoft Academic Search

General Packet Radio Service (GPRS) provides mobile users end-to-end packet-switched services by sharing the radio channels with voice and circuit-switched services. In such a system, radio resource allocation for circuit-switched and packet-switched services is an important issue, which may affect the QoS for both services significantly. In this paper, we propose two algorithms: Dynamic Resource Allocation with Voice and Packet

2003-01-01

203

Cyclic Allocation of Two-Dimensional Data  

Microsoft Academic Search

Various proposals have been made for declustering 2D tiled data on multiple I\\/O devices. Strictly optimal solutions only exist under very restrictive conditions on the tiling of the 2D space or for very few I\\/O devices. In this paper, we explore allocation methods where no strictly optimal solution exists. We propose a general class of allocation methods, referred to as

Sunil Prabhakar; Khaled A. S. Abdel-ghaffar; Divyakant Agrawal; Amr El Abbadi

1998-01-01

204

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

205

Randomization by minimization for unbalanced treatment allocation.  

PubMed

Minimization is a dynamic randomization technique that has been widely used in clinical trials for achieving a balance of prognostic factors across treatment groups, but most often it has been used in the setting of equal treatment allocations. Although unequal treatment allocation is frequently encountered in clinical trials, an appropriate minimization procedure for such trials has not been published. The purpose of this paper is to present novel strategies for applying minimization methodology to such clinical trials. Two minimization techniques are proposed and compared by probability calculation and simulation studies. In the first method, called naïve minimization, probability assignment is based on a simple modification of the original minimization algorithm, which does not account for unequal allocation ratios. In the second method, called biased-coin minimization (BCM), probability assignment is based on allocation ratios and optimized to achieve an 'unbiased' target allocation ratio. The performance of the two methods is investigated in various trial settings including different number of treatments, prognostic factors and sample sizes. The relative merits of the different distance metrics are also explored. On the basis of the results, we conclude that BCM is the preferable method for randomization in clinical trials involving unequal treatment allocations. The choice of different distance metrics slightly affects the performance of the minimization and may be optimized according to the specific feature of trials. PMID:19739238

Han, Baoguang; Enas, Nathan H; McEntegart, Damian

2009-11-30

206

Adaptive dynamic resource allocation in annual eusocial insects: environmental variation will not necessarily promote graded control  

PubMed Central

Background According to the classical model of Macevicz and Oster, annual eusocial insects should show a clear dichotomous "bang-bang" strategy of resource allocation; colony fitness is maximised when a period of pure colony growth (exclusive production of workers) is followed by a single reproductive period characterised by the exclusive production of sexuals. However, in several species graded investment strategies with a simultaneous production of workers and sexuals have been observed. Such deviations from the "bang-bang" strategy are usually interpreted as an adaptive (bet-hedging) response to environmental fluctuations such as variation in season length or food availability. To generate predictions about the optimal investment pattern of insect colonies in fluctuating environments, we slightly modified Macevicz and Oster's classical model of annual colony dynamics and used a dynamic programming approach nested into a recurrence procedure for the solution of the stochastic optimal control problem. Results 1) The optimal switching time between pure colony growth and the exclusive production of sexuals decreases with increasing environmental variance. 2) Yet, for reasonable levels of environmental fluctuations no deviation from the typical bang-bang strategy is predicted. 3) Model calculations for the halictid bee Lasioglossum malachurum reveal that bet-hedging is not likely to be the reason for the graded allocation into sexuals versus workers observed in this species. 4) When environmental variance reaches a critical level our model predicts an abrupt change from dichotomous behaviour to graded allocation strategies, but the transition between colony growth and production of sexuals is not necessarily monotonic. Both, the critical level of environmental variance as well as the characteristic pattern of resource allocation strongly depend on the type of function used to describe environmental fluctuations. Conclusion Up to now bet-hedging as an evolutionary response to variation in season length has been the main argument to explain field observations of graded resource allocation in annual eusocial insect species. However, our model shows that the effect of moderate fluctuations of environmental conditions does not select for deviation from the classical bang-bang strategy and that the evolution of graded allocation strategies can be triggered only by extreme fluctuations. Detailed quantitative observations on resource allocation in eusocial insects are needed to analyse the relevance of alternative explanations, e.g. logistic colony growth or reproductive conflict between queen and workers, for the evolution of graded allocation strategies.

Mitesser, Oliver; Weissel, Norbert; Strohm, Erhard; Poethke, Hans-Joachim

2007-01-01

207

Biochemical simulations: stochastic, approximate stochastic and hybrid approaches  

PubMed Central

Computer simulations have become an invaluable tool to study the sometimes counterintuitive temporal dynamics of (bio-)chemical systems. In particular, stochastic simulation methods have attracted increasing interest recently. In contrast to the well-known deterministic approach based on ordinary differential equations, they can capture effects that occur due to the underlying discreteness of the systems and random fluctuations in molecular numbers. Numerous stochastic, approximate stochastic and hybrid simulation methods have been proposed in the literature. In this article, they are systematically reviewed in order to guide the researcher and help her find the appropriate method for a specific problem.

2009-01-01

208

Biochemical simulations: stochastic, approximate stochastic and hybrid approaches.  

PubMed

Computer simulations have become an invaluable tool to study the sometimes counterintuitive temporal dynamics of (bio-)chemical systems. In particular, stochastic simulation methods have attracted increasing interest recently. In contrast to the well-known deterministic approach based on ordinary differential equations, they can capture effects that occur due to the underlying discreteness of the systems and random fluctuations in molecular numbers. Numerous stochastic, approximate stochastic and hybrid simulation methods have been proposed in the literature. In this article, they are systematically reviewed in order to guide the researcher and help her find the appropriate method for a specific problem. PMID:19151097

Pahle, Jürgen

2009-01-01

209

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

210

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

NASA Astrophysics Data System (ADS)

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

Hong, Jialin; Ji, Lihai; Zhang, Liying

2014-07-01

211

Stochastic patch exploitation model  

PubMed Central

A solitary animal is foraging in a patch consisting of discrete prey items. We develop a stochastic model for the accumulation of gain as a function of elapsed time in the patch. The model is based on the waiting times between subsequent encounters with the prey items. The novelty of the model is in that it renders possible–via parameterization of the waiting time distributions: the incorporation of different foraging situations and patch structures into the gain process. The flexibility of the model is demonstrated with different foraging scenarios. Dependence of gain expectation and variance of the parameters of the waiting times is studied under these conditions. The model allows us to comment upon some of the basic concepts in contemporary foraging theory.

Rita, H.; Ranta, E.

1998-01-01

212

Bunched beam stochastic cooling  

SciTech Connect

The scaling laws for bunched-beam stochastic cooling has been derived in terms of the optimum cooling rate and the mixing condition. In the case that particles occupy the entire sinusoidal rf bucket, the optimum cooling rate of the bunched beam is shown to be similar to that predicted from the coasting-beam theory using a beam of the same average density and mixing factor. However, in the case that particles occupy only the center of the bucket, the optimum rate decrease in proportion to the ratio of the bunch area to the bucket area. The cooling efficiency can be significantly improved if the synchrotron side-band spectrum is effectively broadened, e.g. by the transverse tune spread or by using a double rf system.

Wei, Jie

1992-09-01

213

Bunched beam stochastic cooling  

SciTech Connect

The scaling laws for bunched-beam stochastic cooling has been derived in terms of the optimum cooling rate and the mixing condition. In the case that particles occupy the entire sinusoidal rf bucket, the optimum cooling rate of the bunched beam is shown to be similar to that predicted from the coasting-beam theory using a beam of the same average density and mixing factor. However, in the case that particles occupy only the center of the bucket, the optimum rate decrease in proportion to the ratio of the bunch area to the bucket area. The cooling efficiency can be significantly improved if the synchrotron side-band spectrum is effectively broadened, e.g. by the transverse tune spread or by using a double rf system.

Wei, Jie.

1992-01-01

214

Stochastic reconstruction of sandstones  

PubMed

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

Manwart; Torquato; Hilfer

2000-07-01

215

Nonparametric Bayes Stochastically Ordered Latent Class Models.  

PubMed

Latent class models (LCMs) are used increasingly for addressing a broad variety of problems, including sparse modeling of multivariate and longitudinal data, model-based clustering, and flexible inferences on predictor effects. Typical frequentist LCMs require estimation of a single finite number of classes, which does not increase with the sample size, and have a well-known sensitivity to parametric assumptions on the distributions within a class. Bayesian nonparametric methods have been developed to allow an infinite number of classes in the general population, with the number represented in a sample increasing with sample size. In this article, we propose a new nonparametric Bayes model that allows predictors to flexibly impact the allocation to latent classes, while limiting sensitivity to parametric assumptions by allowing class-specific distributions to be unknown subject to a stochastic ordering constraint. An efficient MCMC algorithm is developed for posterior computation. The methods are validated using simulation studies and applied to the problem of ranking medical procedures in terms of the distribution of patient morbidity. PMID:22505787

Yang, Hongxia; O'Brien, Sean; Dunson, David B

2011-09-01

216

A Fast Distributed Modular Algorithm for Resource Allocation  

Microsoft Academic Search

This paper concerns resource allocation in distributed message passing systems, i.e., the scheduling of accesses to system resources shared among many concurrent processes. Three different kinds of resource allocation problems with varying degrees of generality are considered: the dining philosophers problem, the drinking philosophers problem and the dynamic resource allocation problem. We present an efficient modular resource allocation algorithm that

Injong Rhee

1995-01-01

217

Memory Allocation Costs in Large C and C++ Programs  

Microsoft Academic Search

Dynamic storage allocation is an important part of a large class of computer programs writtenin C and C++. High-performance algorithms for dynamic storage allocation have been, and willcontinue to be, of considerable interest. This paper presents detailed measurements of the cost ofdynamic storage allocation in 11 diverse C and C++ programs using five very different dynamicstorage allocation implementations, including a

David Detlefs; Al Dosser; Benjamin G. Zorn

1994-01-01

218

Size-dependent sex allocation in a simultaneous hermaphrodite parasite  

Microsoft Academic Search

Most models of sex allocation distinguish between sequential and simulta- neous hermaphrodites, although an intermediate sexual pattern, size-depen- dent sex allocation, is widespread in plants. Here we investigated sex allocation in a simultaneous hermaphrodite animal, the tapeworm Schisto- cephalus solidus, in which adult size is highly variable. Sex allocation was determined using stereological techniques, which allow measuring somatic and reproductive

L. Scharer; L. M. Karlsson; M. Christen; C. Wedekind

2001-01-01

219

Algorithm development for SDI weapons system allocation. Final report, December 1987-May 1989  

SciTech Connect

While several SDI weapons systems can provide adequate defense in a one-on-one basis, a coordinated attack by several enemy missiles launched over a substantial volume will be difficult to resist without an efficient command and control system for warfare coordination. This study of weapons allocation - coordination algorithms, is based on dynamical models for the missile/decoy systems including noise effects and uncertainties in the model parameters. Performance of the weapons targeting system may be measured in terms of the expected number of targets eliminated in a given interval (phase of operations) or the expected time to eliminate all the targets in a given region. Scheduling weapons deployment is a problem of constrained optimal (weapons) and state variables. The selection of weapons deployment tactics is based on solution of a complex optimization problem. We have conducted an investigation of advanced modeling, stochastic control, and scheduling methodologies for aspects of the SDI weapons allocation problem - several platforms with assets of different character defending against a diverse collection of targets. The models for such scenarios lead to stochastic scheduling problems that can not be handled by conventional analytical methods. The authors describe several different analytical approaches that have the potential for synthesis of effective engagement algorithms.

Blankenship, G.L.; Bennett, W.

1989-06-01

220

Constructing stochastic networks via ?-RBF networks  

Microsoft Academic Search

Without considering spatial, stochastic, and temporal features inherent in natural neural systems, the computational power of conventional artificial neural networks (ANNs) is limited. In the present paper, we look at the stochastic complexity and construct a stochastic ANN by modeling stochastic fluctuations in the environmental stimuli such that all stimuli are prone to be corrupted by noise or even outliers

Shong-Tun Li; Ernst L. Leiss

1996-01-01

221

Stochastic Loewner evolution driven by Lévy processes  

NASA Astrophysics Data System (ADS)

Standard stochastic Loewner evolution (SLE) is driven by a continuous Brownian motion, which then produces a continuous fractal trace. If jumps are added to the driving function, the trace branches. We consider a generalized SLE driven by a superposition of a Brownian motion and a stable Lévy process. The situation is defined by the usual SLE parameter, ?, as well as ?, which defines the shape of the stable Lévy distribution. The resulting behaviour is characterized by two descriptors: p, the probability that the trace self-intersects, and \\tilde {p} , the probability that it will approach arbitrarily close to doing so. Using Dynkin's formula, these descriptors are shown to change qualitatively and singularly at critical values of ? and ?. It is reasonable to call such changes 'phase transitions'. These transitions occur as ? passes through four (a well-known result) and as ? passes through one (a new result). Numerical simulations are then used to explore the associated touching and near-touching events.

Rushkin, I.; Oikonomou, P.; Kadanoff, L. P.; Gruzberg, I. A.

2006-01-01

222

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

223

Stochastic Dynamics of New Inflation.  

National Technical Information Service (NTIS)

We investigate thoroughly the dynamics of an inflation-driving scalar field in terms of an extended version of the stochastic approach proposed by Starobinsky and discuss the spacetime structure of the inflationary universe. To avoid any complications whi...

K. Nakao Y. Nambu M. Sasaki

1988-01-01

224

Stochastic Equations and Their Application.  

National Technical Information Service (NTIS)

The author presents some simple problems leading to stochastic equations. Then some methods available for the analysis of these equations are briefly reviewed. Finally a quick survey of some recent results in the asymptotic analysis of random evolutions i...

G. C. Papanicolaou

1973-01-01

225

Parameter Estimation for Stochastic Systems.  

National Technical Information Service (NTIS)

A parameter estimation program for stochastic systems (MLPEFSS) is reviewed. The program employs a Gauss-Newton optimization of a maximum likehood criterion to estimate the unknown parameters appearing in a linear, time invariant state space description o...

P. J. G. Loos

1989-01-01

226

Adaptive Stochastic Disturbance Accommodating Control.  

National Technical Information Service (NTIS)

This paper presents a Kalman filter based adaptive disturbance accommodating stochastic control scheme for linear uncertain systems to minimize the adverse effects of both model uncertainties and external disturbances. Instead of dealing with system uncer...

J. George J. L. Crassidis P. Singla

2010-01-01

227

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

228

Planning health services with explicit geographical considerations: a stochastic location–allocation approach  

Microsoft Academic Search

This paper is concerned with modeling for planning health services when geographical considerations in the location of services and in the locations of patients who need services are important. Examples of geographical distribution and organization of health services are the location of hospital outpatient departments within a city, and the provision of hospital-based specialist services, such as cardiac and dental

P. R. Harper; A. K. Shahani; J. E. Gallagher; C. Bowie

2005-01-01

229

Stochasticity in localized synfire chain  

Microsoft Academic Search

We report on stochastic evolutions of firing states through feedforward neural networks with Mexican-Hat-type connectivity. The variance in connectivity, which depends on the pre-synaptic neuron, generates a common noisy input to post-synaptic neurons. We develop a theory to describe the stochastic evolution of the localized synfire chain driven by a common noisy input. The development of a firing state through

Kosuke Hamaguchi; Masato Okada; Michiko Yamana; Kazuyuki Aihara

2005-01-01

230

Stochastic roots of growth phenomena  

NASA Astrophysics Data System (ADS)

We show that the Gompertz equation describes the evolution in time of the median of a geometric stochastic process. Therefore, we induce that the process itself generates the growth. This result allows us further to exploit a stochastic variational principle to take account of self-regulation of growth through feedback of relative density variations. The conceptually well defined framework so introduced shows its usefulness by suggesting a form of control of growth by exploiting external actions.

De Lauro, E.; De Martino, S.; De Siena, S.; Giorno, V.

2014-05-01

231

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

232

Control theory: Deterministic versus stochastic  

NASA Astrophysics Data System (ADS)

Deterministic control theory is not something new since it has been used widely in controlling the optimization of the systems. However, the assertion of stochastic framework found to be more realistic. Hence this paper discusses both deterministic and stochastic control theory and the method used respectively in their problem solving namely numerical standard methods, dynamic programming and Hamilton Jacobi-Bellman equation (HJB). Problems of funding system and its solution by using HJB equation end this study.

Abdul Aziz, Nur Atiq Afiqah; Salleh, Hassilah

2013-04-01

233

The allocation process and between-tree survival probabilities in Dendroctonus frontalis infestations  

Microsoft Academic Search

Conclusion  We have presented two transfer functions for allocating populations ofD. frontals adults in spots: a fixed probabilityTF and a time-temperature dependentTF. Both procedures produced essentially equivalent results when applied to actual population measurements taken from spots.\\u000a The time-temperatureTF was more realistic than the constant probabilityTF, but introduced an added source of variation into the transfer. Temperature was demonstrated to have

D. N. Pope; R. N. Coulson; W. S. Fargo; J. A. Gagne; C. W. Kelly

1980-01-01

234

A formal framework for the study of task allocation in multi-robot systems  

Microsoft Academic Search

Despite more than a decade of experimental work in multi-robot systems, important theoretical aspects of multi-robot coordination mechanisms have, to date, been largely untreated. To address this issue, we focus on the problem of multi-robot task allocation (MRTA). Most work on MRTA has been ad hoc and empirical, with many coordination architectures having been proposed and val- idated in a

Brian P. Gerkey; Maja J Mataric

2003-01-01

235

A Formal Analysis and Taxonomy of Task Allocation in Multi-Robot Systems  

Microsoft Academic Search

Despite more than a decade of experimental work in multi-robot systems, important theoretical aspects of multi-robot coordination mechanisms have, to date, been largely untreated. To address this issue, we focus on the problem of multi-robot task allocation (MRTA). Most work on MRTA has been ad hoc and empirical, with many coordination architectures having been proposed and val- idated in a

Brian P. Gerkey; Maja J. Mataric

2004-01-01

236

Recently Added Antibodies  

Cancer.gov

Reagents Data Portal AntibodiesNCI announces the release of monoclonal antipeptide antibodies from rabbit for distribution on the antibody portal. There are 60 recently added monoclonal antibodies, with 56 generated from mouse and 4 generated from rabbit. Print

237

Avionics Diagnostic System (ADS).  

National Technical Information Service (NTIS)

The presentation will provide system design including a description of the commands, outputs and diagnostic capabilities provided by the ADS we created. Issues and decisions will also be described as will thoughts on potential new features that could be a...

T. Risko

1999-01-01

238

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.

239

ADS pilot program Plan  

NASA Technical Reports Server (NTRS)

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

Clauson, J.; Heuser, J.

1981-01-01

240

Resource allocation for efficient environmental management.  

PubMed

Environmental managers must decide how to invest available resources. Researchers have previously determined how to allocate conservation resources among regions, design nature reserves, allocate funding to species conservation programs, design biodiversity surveys and monitoring programs, manage species and invest in greenhouse gas mitigation schemes. However, these issues have not been addressed with a unified theory. Furthermore, uncertainty is prevalent in environmental management, and needs to be considered to manage risks. We present a theory for optimal environmental management, synthesizing previous approaches to the topic and incorporating uncertainty. We show that the theory solves a diverse range of important problems of resource allocation, including distributing conservation resources among the world's biodiversity hotspots; surveillance to detect the highly pathogenic avian influenza H5N1 virus in Thailand; and choosing survey methods for the insect order Hemiptera. Environmental management decisions are similar to decisions about financial investments, with trade-offs between risk and reward. PMID:20718844

McCarthy, Michael A; Thompson, Colin J; Hauser, Cindy; Burgman, Mark A; Possingham, Hugh P; Moir, Melinda L; Tiensin, Thanawat; Gilbert, Marius

2010-10-01

241

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

242

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

NASA Astrophysics Data System (ADS)

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

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

2000-05-01

243

Nash Social Welfare in Multiagent Resource Allocation  

NASA Astrophysics Data System (ADS)

We study different aspects of the multiagent resource allocation problem when the objective is to find an allocation that maximizes Nash social welfare, the product of the utilities of the individual agents. The Nash solution is an important welfare criterion that combines efficiency and fairness considerations. We show that the problem of finding an optimal outcome is NP-hard for a number of different languages for representing agent preferences; we establish new results regarding convergence to Nash-optimal outcomes in a distributed negotiation framework; and we design and test algorithms similar to those applied in combinatorial auctions for computing such an outcome directly.

Ramezani, Sara; Endriss, Ulle

244

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

245

Stochastic Coupled Cluster Theory  

NASA Astrophysics Data System (ADS)

In an extension of the Full Configuration Interaction Monte Carlo method of Alavi et al.[1], I describe a stochastic algorithm to perform Coupled Cluster Theory[2] which represents excitation amplitudes as populations discrete excitation particles (excips) in the space of excitation operators (excitors). Re-expressing the Coupled Cluster equations as the dynamics of excips in this space, we show that a simple set of rules consisting of spawning, death, and annihilation steps suffice to evolve a distribution of in the space of excitors to sample the Coupled Cluster solution and correctly evaluate its energy. These rules are extremely simple to implement and not truncation-specific and thus this method can calculate solutions to an arbitrary level of truncation. I present results of CCSDTQ calculations on the neon atom with basis sets up to cc-pV6Z as well as calculations on the uniform electron gas beyond the capability of other present methods. [1pt] [1] GH Booth, AJW Thom, A Alavi, J. Chem. Phys. (2009) 131, 054106 [1pt] [2] AJW Thom, Phys. Rev. Lett. (2010) 105, 263004

Thom, Alex J. W.

2013-03-01

246

Trade in Value Added and the Valued Added in Trade  

Microsoft Academic Search

This paper discussed two measures of value added flows between countries ‘Trade in value added’ accounts for value added of one country directly and indirectly embodied in final consumption of another country. ‘Value added in trade’ measures the value added embodied in gross trade flows. The paper shows that both measures result in the same overall net trade of a

Robert Stehrer

2012-01-01

247

Ads.com  

NSDL National Science Digital Library

A site devoted to offering streaming video commercials, ads.com offers online access to a large assortment of television advertisements. Through an attractive interface, users can search for commericials either by brand name or by television show episode. So, for those watching their favorite television program and want to see a commercial that aired during it, ads.com should be the perfect way to access the commercial. Currently, access by TV program is limited to a few shows on ABC and FOX, but the site offers an extensive list of brand/product names to browse. Also of interest is the Inside Ads link, which takes users to a page that gives in-depth commentary on select commercials; an archive of previous comments is also available. Two versions of each commercial are available: low bandwidth and broadband. Media studies researchers, as well as teachers who use media analysis in their lesson plans, should appreciate the easy access to commercials that ads.com provides. And of course, for those who appreciate popular culture, ads.com be great for viewing the latest "you've gotta see that one" commercial.

248

Tree-Based Adaptive Broadcasting of Bandwidth Allocation for Vehicle Ad Hoc Networks  

Microsoft Academic Search

In this paper, we propose a tree-based adaptive broadcasting (TAB) algorithm for data dissemination to improve data access efficiency in vehicle communications. The proposed TAB algorithm first constructs a broadcast tree to determine the broadcast frequency of each data, and splits the broadcast tree into some broadcast wood to generate the broadcast program. In addition, this paper develops an analytical

Gwo-Jiun Horng; Chi-Hsuan Wang; Sheng-Tzong Cheng; Chih-Wei Hsu; Sheng-Fu Su

2010-01-01

249

The March 2000 AD Leo Flare Campaign  

NASA Astrophysics Data System (ADS)

Flares are by their nature random and unpredictable events and flare observations are often the serendipitous result of programs designed for other scientific endeavors. Thus, few observations of flares covering multiple wavelength regimes, with both spectroscopic and photometric information, are available to test stellar flare models. Occasionally, a bold and reckless team will put together a flare campaign, employing suitable statistical arguments to convince the relevant telescope allocation committees that such a campaign will prove fruitful, while hoping desperately for the combination of clear weather, working instruments and cooperative star necessary to warrant the herculean organizational effort. We report here on one such campaign, conducted during March, 2000 on the dM3e flare star AD Leo.

Hawley, S. L.; Johns-Krull, C. M.; Fisher, G. H.; Abbett, W. P.; Seiradakis, J. H.; Avgoloupis, S. I.

2003-10-01

250

A Stochastic Collocation Algorithm for Uncertainty Analysis  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

251

A physics-based stochastic approach to representing unresolved scales in ocean models  

NASA Astrophysics Data System (ADS)

Recently, there has been an enormous development to represent unresolved scales by stochastic processes. But current stochastic techniques remain imperfect because the physical properties of the subgridscale processes are either introduced a posteriori as in data-based approaches, or they are prescribed ad hoc by Gaussian closures as in order reduction techniques. In a unifying approach, we combine elements from deterministic physics-based parameterizations and stochastic techniques to give a self-contained stochastic representation of subgridscale interactions. In a nutshell, the largely fixed spatial patterns of the subgridscale interactions are represented by the interactions of the most-unstable modes, whereas the amplitudes of these interactions are assumed to be stochastic with their statistics given via the amplitude equations of the most-unstable modes. For an efficient implementation, we exploit new, powerful tools such as generalized eigenvalue solvers suited to compute targeted eigenmodes of large dimensional systems, and the Dynamical Orthogonal Field method to solve the stochastic differential equations which yields the entire probability distribution of the flow field. As a first demonstration, we discuss the stochastic representation of baroclinic turbulence in the double gyre circulation.

Viebahn, Jan; Dijkstra, Henk A.

2014-05-01

252

Impact of time delays on stochastic resonance in an ecological system describing vegetation  

NASA Astrophysics Data System (ADS)

In this paper, we investigate the stochastic resonance phenomenon in a vegetation ecological system with time delay, at which the vegetation dynamics is assumed to be disturbed by both intrinsic and extrinsic noises. The signal-to-noise ratio is calculated when a weak periodic signal is added to the system. The impacts of time delay ? and correlation strength k between two noises on the signal-to-noise ratio are discussed, respectively. Our research results show that: (i) the increase of ? or k can enhance the stochastic resonance in the signal-to-noise ratio as a function of intrinsic noise strength ?; (ii) on the contrary, the increase of ? or k can weaken the stochastic resonance in the signal-to-noise ratio as a function of extrinsic noise strength D; and (iii) the increase of ? can lead to double stochastic resonance phenomenon in the signal-to-noise ratio as a function of k.

Han, Qinglin; Yang, Tao; Zeng, Chunhua; Wang, Hua; Liu, Zhiqiang; Fu, Yunchang; Zhang, Chun; Tian, Dong

2014-08-01

253

Allocating scarce resources for endangered species recovery  

Microsoft Academic Search

This article examines the relationship between fiscal year 1990 Fish and Wildlife Service spending on endangered species recovery and the priority ranking assigned by the Fish and Wildlife Service to particular species. The focus of the analysis is on the extent to which resources were allocated to species assigned higher priority rankings. The major conclusions are: species' recovery priority rank

Benjamin M. Simon; Craig S. Leff; Harvey Doerksen

1995-01-01

254

Dynamic allocation for input redundant control systems  

Microsoft Academic Search

In this paper we address control systems with redundant actuators and characterize the concepts of weak and strong input redundancy. Based on this characterization, we propose a dynamic augmentation to a control scheme which performs the plant input allocation with the goal of employing each actuator in a suitable way, based on its magnitude and rate limits. The proposed theory

Luca Zaccarian

2009-01-01

255

Intrahousehold Allocation of Food in Southern Ethiopia  

Microsoft Academic Search

The purpose of this paper is to examine the patterns of intrahousehold food allocation among rural families in Southern Ethiopia. Individual food sufficiency is measured by the total calorie intake of each individual divided by the Recommended Dietary Allowance of calories. This is divided by the household total of this variable to get the individual's share in household food resources.

Kimhi Ayal; Nathan Sosner

2000-01-01

256

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.

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

2010-01-01

257

Analysis of Graph Coloring Register Allocation.  

National Technical Information Service (NTIS)

Graph coloring is the de facto standard technique for register allocation within a compiler. In this paper we examine the importance of the quality of the coloring algorithm and various extensions of the basic graph coloring technique by replacing the col...

D. Koes S. C. Goldstein

2006-01-01

258

Class of Dynamic Nonlinear Resource Allocation Problems.  

National Technical Information Service (NTIS)

We consider a class of dynamic resource allocation problems a specific example of which is the Weapon-Target Assignment problem. This problem is concerned with the optimal assignment of resources in a military engagement. These problems are, in general, N...

P. A. Hosein

1989-01-01

259

Resource allocation and scheduling in cloud computing  

Microsoft Academic Search

Cloud computing is a platform that hosts applications and services for businesses and users to accesses computing as a service. In this paper, we identify two scheduling and resource allocation problems in cloud computing. We describe Hadoop MapReduce and its schedulers, and present recent research efforts in this area including alternative schedulers and enhancements to existing schedulers. The second scheduling

Eman Elghoneimy; Othmane Bouhali; Hussein Alnuweiri

2012-01-01

260

Regional Impacts of Alternative Energy Allocation Strategies.  

National Technical Information Service (NTIS)

The study considers the impacts of the energy crisis and its shortages on the energy management decision process, and the specific gainers and losers of allocation strategies, with tradeoffs in costs of having or not having energy information. Input/outpu...

W. R. Maki P. C. Knobloch

1974-01-01

261

Contingency allocation and management for building projects  

Microsoft Academic Search

A theoretical approach is presented for contingency allocation and management in building projects using the quantification of uncertainty of project cost. The uncertainty of input items to a bill of quantities, namely, quantities of bill items, usage of resources and their prices are quantified as two moments. From these, two moments for project cost are evaluated. The cumulative distribution function

Malik Ranasinghe

1994-01-01

262

Federal Highway Cost Allocation Study, 1997.  

National Technical Information Service (NTIS)

This is the first Federal Highway Cost Allocation Study (HCAS) since 1982. There are two key reasons for conducting this study. The first is to determine how changes in the Federal highway program and user fees which support that program have affected the...

1997-01-01

263

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

264

Efficient Exact Spare Allocation via Boolean Satisfiability  

Microsoft Academic Search

Fabricating large memory and processor arrays is subject to physical failures resulting in yield degradation. The strategy of incorporating spare rows and columns to obtain reasonable production yields was first proposed in the 1970s, and continues to serve as an important role in recent VLSI developments. Since the spare allocation problem (SAP) is NP- complete but requires solving during fabrication,

Fang Yu; Chung-hung Tsai; Yao-wen Huang; D. T. Lee; Hung-yau Lin; Sy-yen Kuo

2005-01-01

265

Real time resource allocation in distributed systems  

Microsoft Academic Search

In this paper we consider a resource allocation problem which is local in the sense that the maximum number of users competing for a particular resource at any time instant is bounded and also at any time instant the maximum number of resources that a user is willing to get is bounded. The problem may be viewed as that of

John H. Reif; Paul G. Spirakis

1982-01-01

266

Discrete Resource Allocation in Visual Working Memory  

ERIC Educational Resources Information Center

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

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

2009-01-01

267

Allocation of transmission fixed charges: an overview  

Microsoft Academic Search

The application of marginal cost in pricing the transmission services has shown not effective mainly due to revenue reconciliation problems. To overcome this, a set of other methods derived from the MW-mile rule has been suggested to allocate transmission fixed costs. This paper compares such methods known as embedded cost methods in a centralized transmission network environment. Although these methods

J. W. Marangon Lima

1996-01-01

268

Multiple UAV task allocation using negotiation  

Microsoft Academic Search

A multiple UAV search and attack mission involves searching for targets in an unknown region, followed by attack on the detected targets. An effective mission involves assigning the tasks to UAVs efficiently. Task allocation becomes difficult when the UAVs have limited range to detect the targets and neighbouring UAVs. The UAVs are also subject to limited communication range. With these

P. B. Sujit; Arpita Sinha; Debasish Ghose

2006-01-01

269

Status Characteristics, Reward Allocation, and Equity  

ERIC Educational Resources Information Center

The relationship between a group's power and prestige or status hierarchy and group members' patterns of reward allocation was investigated. The addition of evidence concerning actual task performance results in the alignment of reward and status rankings and encourages the use of distribution rules stressing equity as opposed to equality.…

Parcel, Toby L.; Cook, Karen S.

1977-01-01

270

Internal Markets for Supply Chain Capacity Allocation  

Microsoft Academic Search

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 markets to involve many employees, finegrained transactions, and frequently varying prices. The paper develops a formal model of such markets, proves their optimality in a baseline

David McAdams; Thomas W. Malone

2005-01-01

271

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

272

Recruiting Resource and Goal Allocation Decision Model.  

National Technical Information Service (NTIS)

This report presents an attempt to construct a mathematical model that could be used to allocate Air Force recruiting effort based on recruiting organization and demographic data available at the Air Force Recruiting Office level. Such a model based on a ...

L. T. Looper C. A. Beswick

1980-01-01

273

Discrete Resource Allocation in Visual Working Memory  

Microsoft Academic Search

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

Brian Barton; Edward F. Ester; Edward Awh

2009-01-01

274

Bandwidth Allocation by Using Generalized Vickrey Auction  

Microsoft Academic Search

Network resources, which are composed of many links at various bandwidths, can be regarded as multiple items with multiple units. A generalized Vickrey auc- tion (GVA) is known as an effective auction proto- col for allocating multiple items and multiple units in a distributed manner. In GVA, the seller can opti- mize the available quantity based on the bidders' pri-

Eiji TAKAHASHI; Yoshiaki TANAKA

275

Auction-Based Effective Bandwidth Allocation Mechanism  

Microsoft Academic Search

This paper proposes a bandwidth allocation system by using GVA (Generalized Vickrey Auction), which can be used for leasing lines, reselling lines, or al- locating bandwidth to individual users. In the proposed system, network resources, which are composed of many links at various bandwidths, are regarded as multiple items with multiple units. It is described how to ap- ply the

Eiji Takahashi; Yoshiaki Tanaka

2003-01-01

276

Allocation and matching in kidney exchange programs.  

PubMed

Living donor kidney transplantation is the preferred treatment for patients suffering from end-stage renal disease. To alleviate the shortage of kidney donors, many advances have been made to improve the utilization of living donors deemed incompatible with their intended recipient. The most prominent of these advances is kidney paired donation (KPD), which matches incompatible patient-donor pairs to facilitate a kidney exchange. This review discusses the various approaches to matching and allocation in KPD. In particular, it focuses on the underlying principles of matching and allocation approaches, the combination of KPD with other strategies such as ABO incompatible transplantation, the organization of KPD, and important future challenges. As the transplant community strives to balance quantity and equity of transplants to achieve the best possible outcomes, determining the right long-term allocation strategy becomes increasingly important. In this light, challenges include making full use of the various modalities that are now available through integrated and optimized matching software, encouragement of transplant centers to fully participate, improving transplant rates by focusing on the expected long-run number of transplants, and selecting uniform allocation criteria to facilitate international pools. PMID:24112284

Glorie, Kristiaan; Haase-Kromwijk, Bernadette; van de Klundert, Joris; Wagelmans, Albert; Weimar, Willem

2014-04-01

277

Spectrum allocation strategies for heterogeneous networks  

Microsoft Academic Search

This work analyzed the trade-off between the area spectral efficiency and outage user rates in heterogeneous cel- lular networks with overlapping picocells. We considered two different models for the spectrum allocation and cell association. The first model employs a spectrum overlapping strategy with an SINR-based cell association. The second model avoids the interference between macrocell and picocell through a spectrum

Rindra Ramamonjison; Kei Sakaguchi; Kiyomichi Araki; Shoji Kaneko; Yoji Kishi; Noriaki Miyazaki

2011-01-01

278

Highway Cost Allocation Update, 1996: Technical Report.  

National Technical Information Service (NTIS)

The update of the highway cost allocation study is the seventh in a recent series begun in the early 1980's by the Kentucky Transportation Cabinet and the Kentucky Transportation Center. The primary objectives were to determine the level of revenue contri...

J. A. Deacon J. G. Pigman

1996-01-01

279

Highway Cost Allocation Update 1998: Technical Report.  

National Technical Information Service (NTIS)

This update of the highway cost allocation study is the eight in a recent series begun in the early 1980's by the Kentucky Transportation Cabinet and the Kentucky Transportation Center. The primary objectives were to determine the level of revenue contrib...

S. S. Jones J. G. Pigman

1998-01-01

280

Adaptive file allocation in distributed computer systems  

Microsoft Academic Search

An algorithm to dynamically reallocate the database files in a computer network is presented. The proposed algorithm uses the best fit approach to allocate and delete beneficial file copies. A key problem of economical estimation of future access and update pattern is discussed and an algorithm based on the Gabor-Kolmogorov learning process is presented to estimate the access and the

Amjad Mahmood; H. U. Khan; H. A. Fatmi

1994-01-01

281

Substructure Allocation in Recursive Interconnection Networks  

Microsoft Academic Search

In a multiuser message passing MIMD sys tem, substructure allocation is an important aspect of sys tem design. In this paper, we present four substructure al location algorithms for a multiuser WK-Recursive network. Two algorithms are bit-map based and two are tree based. The algorithms are compared using simulation.

Ronald Fernandes; Arkady Kanevsky

1993-01-01

282

Lifetime analysis of dynamically allocated objects  

Microsoft Academic Search

The choice of binding time disciplines has major consequences for both the run-time efficiency of programs and the convenience of the language expressing algorithms. Late storage binding time, dynamic allocation, provides the flexibility necessary to implement the complex data structures common in today's object oriented style of programming. In this paper we show that compile-time lifetime analysis can be applied

Cristina Ruggieri; Thomas P. Murtagh

1988-01-01

283

Optimal Allocation of Two-Dimensional Data  

Microsoft Academic Search

Efficient browsing and retrieval of geographically referenced information requires the allocation of data on different storage devices for concurrent retrieval. By dividing a two dimensional space into tiles, a system can allow users to specify regions of interest using a query rectangle and then retrieving all information related to tiles overlapping with the query. In this paper, we derive the

Khaled A. S. Abdel-ghaffar; Amr El Abbadi

1997-01-01

284

Almost sure limit theorems for random allocations  

Microsoft Academic Search

Almost sure limit theorems are presented for random allocations. A general almost sure limit theorem is proved for arrays of random variables. It is applied to obtain almost sure versions of the central limit theorem for the number of empty boxes when the parameters are in the central domain. Almost sure versions of the Poisson limit theorem in the left

István Fazekas; Alexey Chuprunov

2005-01-01

285

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

286

Dynamic Task Allocation for Robots via Auctions  

Microsoft Academic Search

We present an auction-based method for the allo- cation of tasks to a group of robots. The robots operate in a 2D environment for which they have a map. Tasks are locations in the map that have to be visited by the robots. Unexpected obstacles and other delays may prevent a robot from being able to complete its allocated tasks.

Maitreyi Nanjanath; Maria Gini

2006-01-01

287

Where Training Resources Should be Allocated  

Microsoft Academic Search

Proper allocation of training budgets and resources requires fundamental and important business decisions. Unless the organization's training function is a revenue-generating business, the demand for training most likely exceeds capacity and budgets are likely viewed as an expense - which is continually scrutinized. As a result, resources need to be focused on those initiatives that are important and which can

Steven J. Tourville

2005-01-01

288

Prediction based resource allocation in OFDMA  

Microsoft Academic Search

We present a prediction-based resource allocation algorithm (RA) for OFDMA downlink over mobile wireless chan- nels, where prediction errors are incorporated in the problem formulation. A solution based on the empirical characterization of the prediction error is proposed. We test the proposed scheme on a realistic scenario using a practical low complexity channel predictor, suitable for implementation at the mobile

Jorge F. Schmidt; Juan E. Cousseau; Risto Wichman; Stefan Werner

2011-01-01

289

Ad hoc category restructuring.  

PubMed

Participants learned to classify seemingly arbitrary words into categories that also corresponded to ad hoc categories (see, e.g., Barsalou, 1983). By adapting experimental mechanisms previously used to study knowledge restructuring in perceptual categorization, we provide a novel account of how experimental and preexperimental knowledge interact. Participants were told of the existence of the ad hoc categories either at the beginning or the end of training. When the ad hoc labels were revealed at the end of training, participants switched from categorization based on experimental learning to categorization based on preexperimental knowledge in some, but not all, circumstances. Important mediators of the extent of that switch were the amount of performance error experienced during prior learning and whether or not prior knowledge was in conflict with experimental learning. We present a computational model of the trade-off between preexperimental knowledge and experimental learning that accounts for the main results. PMID:17263065

Little, Daniel R; Lewandowsky, Stephan; Heit, Evan

2006-10-01

290

Stochastic simulation of karst conduit networks  

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

291

Stochastic optimal control of spacecraft  

NASA Astrophysics Data System (ADS)

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

Gustafson, Eric Daniel

292

Asymmetric synthesis of pyrimidyl alkanol without adding chiral substances by the addition of diisopropylzinc to pyrimidine-5-carbaldehyde in conjunction with asymmetric autocatalysis  

Microsoft Academic Search

Enantiomerically enriched pyrimidyl alkanol with either S or R configuration was obtained stochastically from the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc without adding chiral substances in conjunction with subsequent asymmetric autocatalysis, leading to amplification of the enantiomeric excess.

Kenso Soai; Itaru Sato; Takanori Shibata; Soichiro Komiya; Masanobu Hayashi; Yohei Matsueda; Hikaru Imamura; Tadakatsu Hayase; Hiroshi Morioka; Hayami Tabira; Jun Yamamoto; Yasunori Kowata

2003-01-01

293

Wireless Ad Hoc Networks  

Microsoft Academic Search

A mobile ad hoc network is a relatively new term for an old technology - a network that does not rely on p re-existing infrastructure. Roots of this technology could be traced back to the early 1970s with the DARPA PRNet and the SURAN projects. The new twitch is the application of this technology in the non-military communication environments. Additionally,

Zygmunt J. Haas; Jing Deng; Ben Liang; Panagiotis Papadimitratos; S. Sajama

2002-01-01

294

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

295

Regional gross value added  

Microsoft Academic Search

SUMMARYThis article presents estimates for regional gross value added (GVA) published in December 2009, using the European Union Nomenclature of Units for Territorial Statistics (NUTS) regions (please see Box 1 for a detailed explanation of the NUTS regional classification). Data are published at the NUTS1 level for the period 1989 to 2008 and at the NUTS2 and NUTS3 level for

Bethan West

2010-01-01

296

Planning the efficient allocation of research funds: an adapted application of a non-parametric Bayesian value of information analysis.  

PubMed

The issue of the efficient allocation of research funds has been addressed using various quantitative methods. Bayesian value of information (VoI) analysis provides an explicit and comprehensive analytic process for the comparison of alternative sources of research. This paper presents an adapted non-parametric application of a VoI analysis of prospective trials comparing alternative adjuvant therapies for postmenopausal women with node positive early breast cancer. The results show that such trials would produce substantial net benefits, though the extent of the net benefits is clearly influenced by the assumed length of usefulness of the research. The application of the VoI methodology shows that such analyses are practical and the recent increase in the use of stochastic decision models in the economic evaluation of health care technologies facilitates further applications of VoI analyses to inform the allocation of research funds. PMID:12098524

Karnon, Jonathan

2002-09-01

297

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

298

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

299

10 CFR 490.703 - Biodiesel fuel use credit allocation.  

Code of Federal Regulations, 2010 CFR

... 2009-01-01 2009-01-01 false Biodiesel fuel use credit allocation. 490.703... ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.703 Biodiesel fuel use credit allocation. (a)...

2009-01-01

300

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

301

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

302

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...

303

7 CFR 3430.311 - Allocation of research funds.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 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...

2011-01-01

304

47 CFR 73.182 - Engineering standards of allocation.  

Code of Federal Regulations, 2013 CFR

...Telecommunication 4 2013-10-01 2013-10-01 false Engineering standards of allocation. 73.182 Section 73.182...BROADCAST SERVICES AM Broadcast Stations § 73.182 Engineering standards of allocation. (a) Sections...

2013-10-01

305

Implementation of the Simplified Arizona Highway Cost Allocation Study Model.  

National Technical Information Service (NTIS)

The Arizona Simplified Model for Highway Cost Allocation Studies (Arizona SMHCAS) was developed in 1999 as an alternative to the complicated model for highway cost allocation then available to the Arizona Department of Transportation. The Arizona SMHCAS w...

J. Carey

2001-01-01

306

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

307

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

308

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

309

26 CFR 26.2632-1 - Allocation of GST exemption.  

Code of Federal Regulations, 2013 CFR

...trust by the same transferor. (b) Lifetime allocations â(1) Automatic allocation...skip occurs during the transferor's lifetime, the transferor's GST exemption...transferred during the transferor's lifetime, other than in a direct...

2013-04-01

310

Research on attainable moment subset of the control allocation system  

NASA Astrophysics Data System (ADS)

The purpose of control allocation is to choose a configuration of the control effectors to meet a specified objective. Mathematically, the attainable moment subset (AMS) produced by control surfaces can be expressed as a mapping of the subset of constrained controls into the moment space. The determination of the AMS is very important to the solving of the allocation problem. For the two-dimensional allocation problem, a numerical algorithm is proposed to solve the AMS on-line. For the complex three-dimensional allocation problem, by analyzing its allocation characteristic, some comprehensive mathematic analyses are given to solve the three-dimension AMS. After that, an improved direct allocation algorithm based on the determination of AMS is proposed. Compared to the common direct allocation algorithm at fast speed, the improved algorithm can find the right facet which intersects with the desired moment and improves the real time performance of the allocation system well.

Shi, Jingping; Zhang, Weiguo

2013-03-01

311

76 FR 29083 - Agriculture Priorities and Allocations System  

Federal Register 2010, 2011, 2012, 2013

...Allocation orders would be distributed equitably among the suppliers...restore the agriculture and food system from terrorist attacks, major...the damages to the railroad system supporting commodity movements...Priorities and Allocations System (FPAS). FEMA in the...

2011-05-19

312

Generalization to stochastic averaging in random vibration.  

National Technical Information Service (NTIS)

Stochastic Averaging is applied to a class of randomly excited single- degree-of-freedom oscillators possessing linear damping and nonlinear stiffness terms. The assumed excitation form involves an externally applied evolutionary Gaussian stochastic proce...

J. R. Red-Horse

1992-01-01

313

Likelihood Ratio Derivative Estimators for Stochastic Systems.  

National Technical Information Service (NTIS)

This paper discusses the likelihood ratio derivative estimation techniques for stochastic systems. After a brief review of the basic concepts, likelihood ratio derivative estimators are presented for the following classes of stochastic processes: time hom...

P. W. Glynn

1989-01-01

314

Stochastic quantization of the electromagnetic field  

Microsoft Academic Search

Stochastic field equations for electromagnetism are presented. The covariance in the ground state is calculated. The question of Lorentz covariance is examined. The connection with ordinary quantum field theory is made. The theory is compared with stochastic electrodynamics.

Mark Davidson

1981-01-01

315

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

316

ADS in a Nutshell  

NASA Astrophysics Data System (ADS)

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

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

1999-05-01

317

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.

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

318

Noise-enhanced capacity via stochastic resonance in an asymmetric binary channel  

Microsoft Academic Search

A nonlinear system is considered where an aperiodic binary input signal is added to an arbitrarily distributed noise and compared to a fixed threshold to determine the binary output signal. Noise enhancement of the transmission of the aperiodic signal via stochastic resonance is demonstrated and studied in this nonlinear information channel. The characterization developed goes up to the calculation of

Francois Chapeau-Blondeau

1997-01-01

319

Ubiquitous Crossmodal Stochastic Resonance in Humans: Auditory Noise Facilitates Tactile, Visual and Proprioceptive Sensations  

Microsoft Academic Search

BackgroundStochastic resonance is a nonlinear phenomenon whereby the addition of noise can improve the detection of weak stimuli. An optimal amount of added noise results in the maximum enhancement, whereas further increases in noise intensity only degrade detection or information content. The phenomenon does not occur in linear systems, where the addition of noise to either the system or the

Eduardo Lugo; Rafael Doti; Jocelyn Faubert; Leslie B. Vosshall

2008-01-01

320

Ubiquitous Crossmodal Stochastic Resonance in Humans: Auditory Noise Facilitates Tactile, Visual and Proprioceptive Sensations  

Microsoft Academic Search

Background: Stochastic resonance is a nonlinear phenomenon whereby the addition of noise can improve the detection of weak stimuli. An optimal amount of added noise results in the maximum enhancement, whereas further increases in noise intensity only degrade detection or information content. The phenomenon does not occur in linear systems, where the addition of noise to either the system or

Eduardo Lugo; Rafael Doti; Jocelyn Faubert

2008-01-01

321

Stochastic models with memory effects  

NASA Astrophysics Data System (ADS)

We aim in this work to derive non-Markovian stochastic models. We generalize the discrete random walk by using the method of conditional arrival probability and different types of time distribution in order to get the memory effect. Similarly, we apply this method in case of continuous time random walk with different time distributions and different jump distributions to get stochastic models with memory effect. Also, we may know the memory effect from the statistical properties of the model, especially the second moment.

Malaikah, Honaida

2012-11-01

322

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

323

Comments on optical stochastic cooling  

SciTech Connect

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

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

2002-10-08

324

Stochastic resonance of quantum discord  

SciTech Connect

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 discord resonance is much more robust against dephasing noise and thermal effects than the entanglement resonance. We also show that, unlike the entanglement resonance, the level of dissipation at which the discord resonance occurs is not sensitive to dephasing noise. These results suggest that it is easier to detect the discord resonance in actual experiments, where the dephasing noise and temperature are difficult to control.

Lee, Chee Kong [Centre for Quantum Technologies, National University of Singapore, 117543 Singapore (Singapore); Kwek, Leong Chuan [Centre for Quantum Technologies, National University of Singapore, 117543 Singapore (Singapore); National Institute of Education and Institute of Advanced Studies, Nanyang Technological University, 637616 Singapore (Singapore); Cao, Jianshu [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2011-12-15

325

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

326

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

327

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

328

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

329

Negotiation for resource allocation in IaaS cloud  

Microsoft Academic Search

Infrastructure As A Service (IaaS) cloud providers manage a large set of computing resources. Resources are provided to cloud consumers on demand in the form of virtual machines. Haizea, a resource lease manager, supports advance reservation, immediate, best effort and deadline sensitive resource allocation policies. Haizea uses resource leases as resource allocation abstraction and provides these leases by allocating virtual

Janki Akhani; Sanjay Chuadhary; Gaurav Somani

2011-01-01

330

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

331

Pricing and Resource Allocation in a Cloud Computing Market  

Microsoft Academic Search

The problem is identified as a pricing driven virtual machine (VM) revenue maximization problem with Markovian traffics in a cloud market composed of hybrid cloud and public cloud. A pooled resource allocation model is built followed by numerical tests. The results indicate that hybrid cloud performs the best and the resource allocation model helps optimally allocate the pooled resources.

Linna Du

2012-01-01

332

Market-based Resource Allocation for Distributed Computing  

Microsoft Academic Search

Market-based resource allocation is expected to be an effective mechanism to allocate resources in a cloud computing environment, where the resources are virtualized and delivered to users as services. In this paper we propose a market mechanism to efficiently allocate multiple computation\\/storage services among multiple participants, or the Cloud Service Exchange. The proposed mechanism enables users (1) to order a

Ikki FUJIWARA; Kento Aid; Isao ONO

2008-01-01

333

A Comparison of Allocation Policies in Wavelength Routing Networks  

Microsoft Academic Search

We consider wavelength routing networks with and without wavelength converters, and several wavelength allocation policies. Through numerical and simulation results we obtain upper and lower bounds on the blocking probabilities for two wavelength allocation policies that are most likely to be used in practice, namely, most-used and first-fit allocation. These bounds are the blocking probabilities obtained by the random wavelength

Yuhong Zhu; George N. Rouskas; Harry G. Perros

2000-01-01

334

A model for railway crew allocation support system  

Microsoft Academic Search

The authors discuss a railway crew allocation problem and propose a model to support schedulers on the computer. They have developed a crew allocation support system which supports trial and error generation of crew service patterns by schedulers. Here they analyze the crew allocation problem for a certain company to build the basic problem structure. Next, they propose a conceptual

Kenji Kataoka; Kiyotoshi Komaya

1992-01-01

335

Delay Analysis for Different Resource Allocation Schemes in Wireless Networks  

Microsoft Academic Search

In this paper, we study the delay performance of wireless network considering different resource allocation schemes with single-hop traffic. Existing works studying the delay performance only consider a given resource allocation scheme, either multi-channel system (sharing bandwidth) or time slotted system (sharing time). The fundamental question ignored is which type of resource allocation scheme produces better delay performance with different

Hongkun Li; Yu Cheng

2010-01-01

336

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

ERIC Educational Resources Information Center

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

Connelly, Marilee N.; Willis, Joe E.

337

EDITORIAL: Stochasticity in fusion plasmas Stochasticity in fusion plasmas  

NASA Astrophysics Data System (ADS)

Structure formation and transport in stochastic plasmas is a topic of growing importance in many fields of plasma physics from astrophysics to fusion research. In particular, the possibility to control transport in the boundary of confined fusion plasmas by resonant magnetic perturbations has been investigated extensively during recent years. A major research achievement was finding that the intense transient particle and heat fluxes associated with edge localized modes (here type-I ELMs) in magnetically confined fusion plasmas can be mitigated or even suppressed by resonant magnetic perturbation fields. This observation opened up a possible scheme to avoid too large erosion and material damage by such transients in future fusion devices such as ITER. However, it is widely recognized that a more basic understanding is needed to extrapolate the results obtained in present experiments to future fusion devices. The 4th workshop on Stochasticity in Fusion Plasmas was held in Jülich, Germany, from 2 to 4 March 2009. This series of workshops aims at gathering fusion experts from various plasma configurations such as tokamaks, stellarators and reversed field pinches to exchange knowledge on structure formation and transport in stochastic fusion plasmas. The workshops have attracted colleagues from both experiment and theory and stimulated fruitful discussions about the basics of stochastic fusion plasmas. Important papers from the first three workshops in 2003, 2005 and 2007 have been published in previous special issues of Nuclear Fusion (stacks.iop.org/NF/44/i=6, stacks.iop.org/NF/46/i=4 and stacks.iop.org/NF/48/i=2). This special issue comprises contributions presented at the 4th SFP workshop, dealing with the main subjects such as formation of stochastic magnetic layers, energy and particle transport in stochastic magnetic fields, plasma response to external, non-axis-symmetric perturbations and last but not least application of resonant magnetic perturbations for ELM control and implications for ITER. The next workshop is planned for February/March 2011 in Jülich. For details see http://www.fz-juelich.de/sfp/. We hope that this special issue of Nuclear Fusion will further stimulate interest in the fascinating and important subject of stochasticity in fusion plasmas.

Unterberg, Bernhard

2010-03-01

338

Stochastic Quantization Method in Operator Formalism  

Microsoft Academic Search

The stochastic quantization method is developed in a possible ``Heisenberg'' operator theory of stochastic processes so designed as to keep a formal analogy to quantum mechanics. The general theory is first formulated for stochastic processes of the Wiener type and then its application to quantization of boson fields is presented. It seems that the operator formalism is convenient to examine

Mikio Namiki; Yoshiya Yamanaka

1983-01-01

339

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

340

An Optimal Method for Stochastic Composite Optimization  

Microsoft Academic Search

This paper considers an important class of convex programming problems, namely, the stochastic composite optimization (SCO), whose objective function is given by the summation of general nonsmooth and smooth stochastic components. Since SCO covers non-smooth, smooth and stochastic convex optimization as certain special cases, a valid lower bound on the rate of convergence for solving these problems is known from

Guanghui Lan

2009-01-01

341

Stochastic approaches for modelling in vivo reactions  

Microsoft Academic Search

In recent years, stochastic modelling has emerged as a physically more realistic al- ternative for modelling in vivo reactions. There are numerous stochastic approaches available in the literature; most of these assume that observed random uctuations are a consequence of the small number of reacting molecules. We review some im- portant developments of the stochastic approach and consider its suitability

Thomas E. Turner; Santiago Schnell; Kevin Burrage

2004-01-01

342

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.

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

2006-01-01

343

Energy Uptake and Allocation during Ontogeny  

PubMed Central

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

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

2010-01-01

344

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".

345

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.

346

ADS Abstract Service Enhancements  

NASA Astrophysics Data System (ADS)

The Astrophysics Data System is enhancing functionality and access to the Abstract Service in several areas. A new WAIS server running the freeWAIS search engine has been added to the existing HTTP and ANSA-based servers. Abstract coverage will be expanded to include more of the NASA ``RECON'' categories as well as abstracts obtained directly from astronomical journals. In addition, we are enhancing the service to include full journal articles in a suitable electronic format.

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

347

Network aware resource allocation in distributed clouds  

Microsoft Academic Search

We consider resource allocation algorithms for distributed cloud systems, which deploy cloud-computing resources that are geographically distributed over a large number of locations in a wide-area network. This distribution of cloud-computing resources over many locations in the network may be done for several reasons, such as to locate resources closer to users, to reduce bandwidth costs, to increase availability, etc.

Mansoor Alicherry; T. V. Lakshman

2012-01-01

348

Rethinking reinforcement: allocation, induction, and contingency.  

PubMed

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

Baum, William M

2012-01-01

349

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

350

Communication-Aware Processor Allocation for Supercomputers  

Microsoft Academic Search

We give processor-allocation algorithms for grid architec- tures, where the objective is to select processors from a set of available processors to minimize the average number of communication hops. The associated clustering problem is as follows: Given n points in ?d, find a size-k subset with minimum average pairwise L1 distance. We present a natural approximation algorithm and show that

Michael A. Bender; David P. Bunde; Erik D. Demaine; Sándor P. Fekete; Vitus J. Leung; Henk Meijer; Cynthia Ann Phillips

2004-01-01

351

Determinants of time allocation across the lifespan  

Microsoft Academic Search

This paper lays the groundwork for a theory of time allocation across the life course, based on the idea that strength and\\u000a skill vary as a function of age, and that return rates for different activities vary as a function of the combination of strength\\u000a and skills involved in performing those tasks. We apply the model to traditional human subsistence

Michael Gurven; Hillard Kaplan

2006-01-01

352

Power allocation for coded cooperative communications  

Microsoft Academic Search

A power allocation in a coded cooperation is investigated. For given a total transmit power, an optimal transmit power ratio is obtained in a sense that the average received signal-to-noise ratio (SNR) from the source node and that from the relay node are equal at the sink node. Simulation for a rate compatible punctured convolutional (RCPC) code-based cooperation shows that

Naruhiko Fujiwara; Makoto Yasutake; Chen Sun; Jun Cheng; Yoichiro Watanabe

2009-01-01

353

Discrete Dynamic Programming and Capital Allocation  

Microsoft Academic Search

Dynamic programming algorithms are developed for optimal capital allocation subject to budget constraints. We extend the work of Weingartner [Weingartner, H. M. 1966. Capital budgeting of interrelated projects: Survey and synthesis. Management Sci. 12(7, March) 485-516.] and Weingartner and Ness [Weingartner, H. M., D. N. Ness. 1967. Methods for the solution of the multi-dimensional 0\\/1 knapsack problem. Oper. Res. 15(1,

G. L. Nemhauser; Z. Ullmann

1969-01-01

354

Rethinking Reinforcement: Allocation, Induction, and Contingency  

PubMed Central

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

Baum, William M

2012-01-01

355

Position based CDMA with multiuser detection (P-CDMA\\/MUD) for wireless ad hoc networks  

Microsoft Academic Search

We propose a novel position-based MAC protocol based on multiuser detection for wireless ad hoc networks. We solve the duplex scheduling problem in ad hoc networks and allocate user signatures dynamically based on position. Our protocol leverages previous advances in low-power GPS receivers and low-complexity multiuser detectors. By using multiuser detection, we dispense with the notion of collisions at the

Volkan Rodoplu; Teresa H. Meng

2000-01-01

356

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

357

Stochastic Models of Sperm Motility.  

National Technical Information Service (NTIS)

Stochastic models for sperm motion are investigated. The intention is to use these models as an aid to fertility diagnosis. The sperm track data are modeled as a smooth mean track plus a two-dimensional residual which divides naturally into along-track an...

B. J. McCabe B. Belkin D. H. Wagner K. M. Sommar

1987-01-01

358

Stochastic Modelling of Genetic Algorithms  

Microsoft Academic Search

This paper presents stochastic models for two classes of Genetic Algorithms. We present important distinctions throughout between classes of Genetic Algorithms which sample with and without replacement, in terms of their search dynamics. For both classes of algorithm, we derive sufficient conditions for convergence, and analyse special cases of Genetic Algorithm optimisation. We also derive a long-run measure of crossover

David Reynolds; Jagannathan Gomatam

1996-01-01

359

Object Recognition Using Stochastic Optimization  

Microsoft Academic Search

We describe an approach to object recognition in which the image-to-model match is based on stochastic optimization. During the recognition process, an internal model is matched with a novel object view. To compensate for changes in viewing conditions (such as illumination, viewing direction), the model is controlled by a number of parameters. The matching is obtained by seeking a setting

Shimon Ullman; Assaf Zeira

1997-01-01

360

Computational stochastic mechanics – recent advances  

Microsoft Academic Search

In this paper some of the most recent developments of computational stochastic structural mechanics and analysis are reviewed. These concepts allow a rational treatment of statistical uncertainties involved in structural analysis and design. Particular emphasis is put on the improvement of the computational efficiency of various methods, such as Monte Carlo simulation, etc.

G. I. Schuëller

2001-01-01

361

Transformation invariant stochastic catastrophe theory  

Microsoft Academic Search

Catastrophe theory is a mathematical formalism for modeling nonlinear systems whose discontinuous behavior is determined by smooth changes in a small number of driving parameters. Fitting a catastrophe model to noisy data constitutes a serious challenge, however, because catastrophe theory was formulated specifically for deterministic systems. Loren Cobb addressed this challenge by developing a stochastic counterpart of catastrophe theory (SCT)

Eric-Jan Wagenmakers; Peter C. M. Molenaar; Raoul P. P. P. Grasman; Pascal A. I. Hartelman

2005-01-01

362

Complete Models with Stochastic Volatility  

Microsoft Academic Search

The paper proposes an original class of models for the continuous-time price process of a financial security with nonconstant volatility. The idea is to define instantaneous volatility in terms of exponentially weighted moments of historic log-price. The instantaneous volatility is therefore driven by the same stochastic factors as the price process, so that, unlike many other models of nonconstant volatility,

David G. Hobson; L. C. G. Rogers

1998-01-01

363

Brownian motors and stochastic resonance.  

PubMed

We study the transport properties for a walker on a ratchet potential. The walker consists of two particles coupled by a bistable potential that allow the interchange of the order of the particles while moving through a one-dimensional asymmetric periodic ratchet potential. We consider the stochastic dynamics of the walker on a ratchet with an external periodic forcing, in the overdamped case. The coupling of the two particles corresponds to a single effective particle, describing the internal degree of freedom, in a bistable potential. This double-well potential is subjected to both a periodic forcing and noise and therefore is able to provide a realization of the phenomenon of stochastic resonance. The main result is that there is an optimal amount of noise where the amplitude of the periodic response of the system is maximum, a signal of stochastic resonance, and that precisely for this optimal noise, the average velocity of the walker is maximal, implying a strong link between stochastic resonance and the ratchet effect. PMID:22225377

Mateos, José L; Alatriste, Fernando R

2011-12-01

364

Stochastic Control Problems with Delay  

Microsoft Academic Search

We consider optimal control problems for systems described by stochas- tic dieren tial equations with delay. We state conditions for certain classes of such systems under which the stochastic control problems become nite-dimensional . These conditions are illustrated with three applications. First, we solve some linear quadratic problems with delay. Then we nd the optimal consumption rate in a -

Harald Bauer; Ulrich Rieder

2005-01-01

365

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

366

Stochastic processes in turbulent transport  

Microsoft Academic Search

This is a set of four lectures devoted to simple ideas about turbulent transport, a ubiquitous non-equilibrium phenomenon. In the course similar to that given by the author in 2006 in Warwick [45], we discuss lessons which have been learned from naive models of turbulent mixing that employ simple random velocity ensembles and study related stochastic processes. In the first

Krzysztof Gawedzki

2008-01-01

367

Stochastic Simulation of Chemical Kinetics  

Microsoft Academic Search

Stochastic chemical kinetics describes the time evolution of a well- stirred chemically reacting system in a way that takes into account the fact that molecules come in whole numbers and exhibit some degree of randomness in their dynamical behavior. Researchers are increasingly using this approach to chemical kinetics in the analysis of cellular systems in biology, where the small molecular

Daniel T. Gillespie

2007-01-01

368

Stochastic Models of Long-Term Hydrological Data using a Bayesian Approach: The Challenges of Multi-site Data  

NASA Astrophysics Data System (ADS)

Multi-site stochastic simulations of long-term rainfall and streamflow are used as hydrological inputs for water resource allocation models used to estimate drought risks. A general framework for evaluating the performance of competing multi-site stochastic model parameterisations has been developed. This framework includes a Bayesian approach to quantify parameter uncertainty. Diagnostics used to evaluate model performance are their ability to reproduce important extreme observed statistics and Bayes Factors to calculate model probabilities. Current models included in this framework are the lag-one autoregressive model and the two-state hidden Markov model. The challenges in implementing a Bayesian approach for these multi-site stochastic models will be outlined. The case study used is the hydrological data from Sydney's main water supply catchment; the Warragamba Catchment. The practical impact of evaluating parameter uncertainty is confirmed by illustrating that extreme drought risks are significantly underestimated if parameter uncertainty is ignored.

Thyer, M. A.; Frost, A. J.; Kuczera, G. A.

2005-05-01

369

An ant colony optimization model for wireless ad-hoc network autoconfiguration  

Microsoft Academic Search

The dynamic host configuration protocol (DHCP) has been a commonly employed technique to distribute IP addresses on networks where static address allocation may not be appropriate. DHCP is normally feasible on networks that are client-server based as it needs a server for address management. Wireless ad hoc networks on the other hand do not have a central entity that would

Vignesh Kumar; Eric Cole

2005-01-01

370

Joint congestion control and media access control design for ad hoc wireless networks  

Microsoft Academic Search

Abstmct-We present a model for the joint design of con- gestion control and media access control (MAC) for ad hoc wireless networks. Using contention graph and contention ma- trix, we formulate resource allocation in the network as a utility maximization problem with constraints that arise from contention for channel access. We present two algorithms that are not only distributed spatially,

Lijun Chen; Steven H. Low; John C. Doyle

2005-01-01

371

Partage équitable de la bande passante dans les réseaux ad hoc  

Microsoft Academic Search

Some previous works have shown that the DCF mode within the IEEE 802.11 stan- dard can be inappropriate for many ad hoc configurations. In some situations, the bandwidth allocation between multiple flows can be extremely unfair. Some solutions have already at- tempted to solve these problems, either by modifying the MAC layer, or by regulating the flow throughput at a

Rémi Vannier; Isabelle Guérin-Lassous

2008-01-01

372

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

373

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

374

On deformations of AdS n × S n supercosets  

NASA Astrophysics Data System (ADS)

We study the deformed AdS 5 × S 5 supercoset model of arXiv:1309.5850 which depends on one parameter ? and has classical quantum group symmetry. We confirm the conjecture that in the "maximal" deformation limit, ? ? ?, this model is T-dual to "flipped" double Wick rotation of the target space AdS 5 × S 5, i.e. dS 5 × H 5 space supported by an imaginary 5-form flux. In the imaginary deformation limit, ? ? i, the corresponding target space metric is of a pp-wave type and thus the resulting light-cone gauge S-matrix becomes relativistically invariant. Omitting non-unitary contributions of imaginary WZ terms, we find that this tree-level S-matrix is equivalent to that of the generalized sine-Gordon model representing the Pohlmeyer reduction of the undeformed AdS 5 × S 5 superstring model. We also study in some detail similar deformations of the AdS 3 × S 3 and AdS 2 × S 2 supercosets. The bosonic part of the deformed AdS 3 × S 3 model happens to be equivalent to the symmetric case of the sum of the Fateev integrable deformation of the SL(2) and SU(2) principal chiral models, while in the AdS 2 × S 2 case the role of the Fateev model is played by the 2d "sausage" model. The ? = i limits are again directly related to the Pohlmeyer reductions of the corresponding AdS n × S n supercosets: (2,2) super sine-Gordon model and its complex sine-Gordon analog. We also discuss possible deformations of AdS 3 × S 3 with more than one parameter.

Hoare, B.; Roiban, R.; Tseytlin, A. A.

2014-06-01

375

ADS Article Service  

NSDL National Science Digital Library

The Astrophysics Data System, a database funded by the US National Aeronautics and Space Administration, provides access to scanned astronomical journal articles. The database currently contains sixteen journals, including Astronomy & Astrophysics and Meteoritics & Planetary Sciences, from which articles may be viewed. To find articles, specify volume number and page or plate number. The database is restricted to archived journals; most journals are available through 1996, with a few available through 1997. In addition, the articles can be accessed through separate table of contents and abstract services also provided by ADS.

376

Adding Slide Rule  

NSDL National Science Digital Library

In this activity, students construct adding slide rules, scaled with linear calibrations like ordinary rulers. Students learn to move these scales relative to each other in ways that add and subtract distances, thus calculating sums and differences. This is Activity A1 in the "Far Out Math" educator's guide. Lessons within the guide include activities in which students measure, compare quantities as orders of magnitude, use scientific notation, and develop an understanding of exponents and logarithms using examples from NASA's GLAST mission. These are skills needed to understand the very large and very small quantities characteristic of astronomical observations. Note: In 2008, the GLAST mission was renamed Fermi, for the physicist Enrico Fermi.

377

An xp model on AdS2 spacetime  

NASA Astrophysics Data System (ADS)

In this paper we formulate the xp model on the AdS2 spacetime. We find that the spectrum of the Hamiltonian has positive and negative eigenvalues, whose absolute values are given by a harmonic oscillator spectrum, which in turn coincides with that of a massive Dirac fermion in AdS2. We extend this result to generic xp models which are shown to be equivalent to a massive Dirac fermion on spacetimes whose metric depend of the xp Hamiltonian. Finally, we construct the generators of the isometry group SO(2,1) of the AdS2 spacetime, and discuss the relation with conformal quantum mechanics.

Molina-Vilaplana, Javier; Sierra, Germán

2013-12-01

378

Finite-time stabilization for a class of stochastic nonlinear systems via output feedback.  

PubMed

This paper investigates the problem of global finite-time stabilization in probability for a class of stochastic nonlinear systems. The drift and diffusion terms satisfy lower-triangular or upper-triangular homogeneous growth conditions. By adding one power integrator technique, an output feedback controller is first designed for the nominal system without perturbing nonlinearities. Based on homogeneous domination approach and stochastic finite-time stability theorem, it is proved that the solution of the closed-loop system will converge to the origin in finite time and stay at the origin thereafter with probability one. Two simulation examples are presented to illustrate the effectiveness of the proposed design procedure. PMID:24530195

Zha, Wenting; Zhai, Junyong; Fei, Shumin; Wang, Yunji

2014-05-01

379

Supersymmetric warped AdS in extended topologically massive supergravity  

NASA Astrophysics Data System (ADS)

We determine the most general form of off-shell N=(1,1) supergravity field configurations in three dimensions by requiring that at least one off-shell Killing spinor exists. We then impose the field equations of the topologically massive off-shell supergravity and find a class of solutions whose properties crucially depend on the norm of the auxiliary vector field. These are spacelike-squashed and timelike-stretched AdS3 for the spacelike and timelike norms, respectively. At the transition point where the norm vanishes, the solution is null warped AdS3. This occurs when the coefficient of the Lorentz-Chern-Simons term is related to the AdS radius by ??=2. We find that the spacelike-squashed AdS3 can be modded out by a suitable discrete subgroup of the isometry group, yielding an extremal black hole solution which avoids closed timelike curves.

Deger, N. S.; Kaya, A.; Samtleben, H.; Sezgin, E.

2014-07-01

380

Prey risk allocation in a grazing ecosystem.  

PubMed

Understanding the behaviorally mediated indirect effects of predators in ecosystems requires knowledge of predator-prey behavioral interactions. In predator-ungulate-plant systems, empirical research quantifying how predators affect ungulate group sizes and distribution, in the context of other influential variables, is particularly needed. The risk allocation hypothesis proposes that prey behavioral responses to predation risk depend on background frequencies of exposure to risk, and it can be used to make predictions about predator-ungulate-plant interactions. We determined non-predation variables that affect elk (Cervus elaphus) group sizes and distribution on a winter range in the Greater Yellowstone Ecosystem (GYE) using logistic and log-linear regression on surveys of 513 1-km2 areas conducted over two years. Employing model selection techniques, we evaluated risk allocation and other a priori hypotheses of elk group size and distributional responses to wolf (Canis lupus) predation risk while accounting for influential non-wolf-predation variables. We found little evidence that wolves affect elk group sizes, which were strongly influenced by habitat type and hunting by humans. Following predictions from the risk allocation hypothesis, wolves likely created a more dynamic elk distribution in areas that they frequently hunted, as elk tended to move following wolf encounters in those areas. This response should dilute elk foraging pressure on plant communities in areas where they are frequently hunted by wolves. We predict that this should decrease the spatial heterogeneity of elk impacts on grasslands in areas that wolves frequently hunt. We also predict that this should decrease browsing pressure on heavily browsed woody plant stands in certain areas, which is supported by recent research in the GYE. PMID:16705980

Gude, Justin A; Garrott, Robert A; Borkowski, John J; King, Fred

2006-02-01

381

Vertex Operators for AdS3 with Ramond Background  

Microsoft Academic Search

The computation of exact vertex operators for the Type IIB superstring in an AdS3 × S3 background with Ramond-Ramond flux is described. The components of these vertex operators are shown to satisfy the supergravity linearized equations of motion for the six-dimensional (2,0) theory of a supergravity and tensor multiplet expanded around AdS3 × S3 spacetime.

Louise Dolan

2001-01-01

382

Vertex Operators for AdS3 with Ramond Background  

Microsoft Academic Search

The computation of exact vertex operators for the Type IIB superstring in an AdS3×S3 background with Ramond-Ramond flux is described. The components of these vertex operators are shown to satisfy the supergravity linearized equations of motion for the six-dimensional (2,0) theory of a supergravity and tensor multiplet expanded around AdS3×S3 spacetime.

Louise Dolan

2001-01-01

383

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

384

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

385

Allocation of inspection resources for international safeguards  

SciTech Connect

Increasing numbers and complexity of facilities inspected by the International Atomic Energy Agency will require difficult decisions about the levels of safeguards to be assigned to materials and facilities should limitations on inspection resources continue. This paper examines some alternative strategies for assigning inspection effort that could improve effectiveness and efficiency of safeguards compared with current inspection practice. These allocation concepts are: (1) extension of inspection planning to include material strata and accounting areas that encompass multiple facilities and (2) the use of randomization of the quality and frequency of inspections and inspection activities.

Markin, J.T.

1987-01-01

386

Communication-Aware Processor Allocation for Supercomputers  

Microsoft Academic Search

\\u000a We give processor-allocation algorithms for grid architectures, where the objective is to select processors from a set of\\u000a available processors to minimize the average number of communication hops.\\u000a \\u000a \\u000a The associated clustering problem is as follows: Given n points in Rd\\\\mathcal{R}^d, find a size-k subset with minimum average pairwise L\\u000a 1 distance. We present a natural approximation algorithm and show that

Michael A. Bender; David P. Bunde; Erik D. Demaine; Sándor P. Fekete; Vitus J. Leung; Henk Meijer; Cynthia A. Phillips

2005-01-01

387

Wavelet entropy of stochastic processes  

NASA Astrophysics Data System (ADS)

We compare two different definitions for the wavelet entropy associated to stochastic processes. The first one, the normalized total wavelet entropy (NTWS) family [S. Blanco, A. Figliola, R.Q. Quiroga, O.A. Rosso, E. Serrano, Time-frequency analysis of electroencephalogram series, III. Wavelet packets and information cost function, Phys. Rev. E 57 (1998) 932-940; O.A. Rosso, S. Blanco, J. Yordanova, V. Kolev, A. Figliola, M. Schürmann, E. Ba?ar, Wavelet entropy: a new tool for analysis of short duration brain electrical signals, J. Neurosci. Method 105 (2001) 65-75] and a second introduced by Tavares and Lucena [Physica A 357(1) (2005) 71-78]. In order to understand their advantages and disadvantages, exact results obtained for fractional Gaussian noise ( -1stochastic processes.

Zunino, L.; Pérez, D. G.; Garavaglia, M.; Rosso, O. A.

2007-06-01

388

Stochastic dynamics of cholera epidemics  

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

389

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.

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

2014-01-01

390

Stochastic models for relativistic diffusion  

SciTech Connect

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

Baeumer, Boris; Meerschaert, Mark M.; Naber, Mark [Department of Mathematics and Statistics, University of Otago, Dunedin (New Zealand); Department of Statistics and Probability, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Mathematics, Monroe County Community College, Monroe, Michigan 48161 (United States)

2010-07-15

391

Stochastic Multicriteria Acceptability Analysis (SMAA)  

Microsoft Academic Search

\\u000a Stochastic multicriteria acceptability analysis (SMAA) is a family of methods for aiding multicriteria group decision making\\u000a in problems with uncertain, imprecise or partially missing information. These methods are based on exploring the weight space\\u000a in order to describe the preferences that make each alternative the most preferred one, or that would give a certain rank\\u000a for a specific alternative. The

Risto Lahdelma; Pekka Salminen

392

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

393

Complete Models with Stochastic Volatility  

Microsoft Academic Search

The paper proposes an original class of models for the continuous time price processof a financial security with non-constant volatility. The idea is to define instantaneousvolatility in terms of exponentially-weighted moments of historic log-price. The instantaneousvolatility is therefore driven by the same stochastic factors as the price process, sothat unlike many other models of non-constant volatility, it is not necessary

David G. Hobson; L. c. g. Rogers

1996-01-01

394

Stochastic Gravity: Theory and Applications  

NASA Astrophysics Data System (ADS)

Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of the stress-energy tensor of quantum fields, stochastic semiclassical gravity is based on the Einstein-Langevin equation, which has, in addition, sources due to the noise kernel. The noise kernel is the vacuum expectation value of the (operator-valued) stress-energy bitensor, which describes the fluctuations of quantum-matter fields in curved spacetimes. A new improved criterion for the validity of semiclassical gravity may also be formulated from the viewpoint of this theory. In the first part of this review we describe the fundamentals of this new theory via two approaches: the axiomatic and the functional. The axiomatic approach is useful to see the structure of the theory from the framework of semiclassical gravity, showing the link from the mean value of the stress-energy tensor to the correlation functions. The functional approach uses the Feynman-Vernon influence functional and the Schwinger-Keldysh closed-time-path effective action methods. In the second part, we describe three applications of stochastic gravity. First, we consider metric perturbations in a Minkowski spacetime, compute the two-point correlation functions of these perturbations and prove that Minkowski spacetime is a stable solution of semiclassical gravity. Second, we discuss structure formation from the stochastic-gravity viewpoint, which can go beyond the standard treatment by incorporating the full quantum effect of the inflaton fluctuations. Third, using the Einstein-Langevin equation, we discuss the backreaction of Hawking radiation and the behavior of metric fluctuations for both the quasi-equilibrium condition of a black-hole in a box and the fully nonequilibrium condition of an evaporating black hole spacetime. Finally, we briefly discuss the theoretical structure of stochastic gravity in relation to quantum gravity and point out directions for further developments and applications.

Hu, Bei Lok; Verdaguer, Enric

2008-05-01

395

ANF Stochastic Low Rate Stimulation  

Microsoft Academic Search

Science has been researching on the physiology of the human hearing, and in the last decades, on the mechanism of the neural\\u000a stimulus generation towards the nervous system. The objective of this research is to develop an algorithm that generalizes\\u000a the stochastic spike pattern of the auditory nerve fibers (ANF) formulated by Meddis, which fulfils the Volley principle (principle\\u000a that

396

Stochastic and chaotic relaxation oscillations  

SciTech Connect

For relaxation oscillators stochastic and chaotic dynamics are investigated. The effect of random perturbations upon the period is computed. For an extended system with additional state variables chaotic behavior can be expected. As an example, the Van der Pol oscillator is changed into a third-order system admitting period doubling and chaos in a certain parameter range. The distinction between chaotic oscillation and oscillation with noise is explored. Return maps, power spectra, and Lyapunov exponents are analyzed for that purpose.

Grasman, J.; Roerdink, J.B.T.M.

1989-02-01

397

Adding and Subtracting Integers  

NSDL National Science Digital Library

Now that you have mastered the common math operations of adding, subtracting, multiplying and dividing, you are ready to tackle some more challenging, yet practical problems. For example: How much money do you have if your Mom paid you $20 for every time you mowed the lawn, but you had to pay your little brother $5 for every time he helped you, and together you accomplished the job 7 times? Or how about this one: if you picked 5 apples but 2 were rotten and you had to divide them equally between you and your five friends, how much would each person get? Current Knowledge You will need a piece of paper to record information and to write down examples, so grab one now. Number the paper from 1 to 10. Get with a partner and write down how you think the equations to solve the above problems will be written. Write these ...

Richins, Mrs.

2008-09-10

398

Topics in applied stochastic dynamics  

NASA Astrophysics Data System (ADS)

Randomness in natural systems come from various sources, for example from the discrete nature of the underlying dynamical process when viewed on a small scale. In this thesis we study the effect of stochasticity on the dynamics in three applications, each with different sources and effects of randomness. In the first application we study the Hodgkin-Huxley model of the neuron with a random ion channel mechanism via numerical simulation. Randomness affects the nonlinear mechanism of a neuron's firing behavior by spike induction as well as by spike suppression. The sensitivity to different types of channel noise is explored and robustness of the dynamical properties is studied using two distinct stochastic models. In the second application we compare and contrast the effectiveness of mixing of a passive scalar by stirring using different notions of mixing efficiency. We explore the non-commutativity of the limits of large Peclet numbers and large spatial scale separation between the flow and sources and sinks, and propose and examine a conceptual approach that captures some compatible features of the different models and measures of mixing. In the last application we design a stochastic dynamical system that mimics the properties of so-called homogeneous Rayleigh-Benard convection and show that arbitrary small noise changes the dynamical properties of the model. The system's properties are further exam fined using the first exit time problem. The three applications show that randomness of small magnitude may play important and counterintuitive roles in determining a system's properties.

Bodova, Katarina

399

Stochastic inflation and nonlinear gravity  

SciTech Connect

We show how nonlinear effects of the metric and scalar fields may be included in stochastic inflation. Our formalism can be applied to non-Gaussian fluctuation models for galaxy formation. Fluctuations with wavelengths larger than the horizon length are governed by a network of Langevin equations for the physical fields. Stochastic noise terms arise from quantum fluctuations that are assumed to become classical at horizon crossing and that then contribute to the background. Using Hamilton-Jacobi methods, we solve the Arnowitt-Deser-Misner constraint equations which allows us to separate the growing modes from the decaying ones in the drift phase following each stochastic impulse. We argue that the most reasonable choice of time hypersurfaces for the Langevin system during inflation is {ital T}=ln({ital Ha}), where {ital H} and {ital a} are the local values of the Hubble parameter and the scale factor, since {ital T} is the natural time for evolving the short-wavelength scalar field fluctuations in an inhomogeneous background.

Salopek, D.S. (NASA/Fermilab Astrophysics Center, P. O. Box 500 MS-209, Batavia, Illinois 60510 (US)); Bond, J.R. (Canadian Institute for Advanced Research Program, Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto (Canada))

1991-02-15

400

Self-Interest and Fairness in Problems of Resource Allocation: Allocators Versus Recipients  

Microsoft Academic Search

Two studies explored the tension between self-interest and the equality norm in problems of resource allocation. Study 1 presented graduate business students with a hypothetical task requiring them to make a series of managerial decisions. On learning the outcome of those decisions, they were asked to divide a bonus pool between self and a rival manager (who had opted for

Kristina A. Diekmann; Steven M. Samuels; Lee Ross; Max H. Bazerman

1997-01-01

401

Processor Allocation on Cplant: Achieving General Processor Locality Using One-Dimensional Allocation Strategies  

Microsoft Academic Search

The Computational Plant or Cplant is a commodity- based supercomputer under development at Sandia Na- tional Laboratories. This paper describes resource- allocation strategies to achieve processor locality for par- allel jobs in Cplant and other supercomputers. Users of Cplant and other Sandia supercomputers submit parallel jobs to a job queue. When a job is scheduled to run, it is as-

Vitus J. Leung; Esther M. Arkin; Michael A. Bender; David P. Bunde; Jeanette Johnston; Alok LalJoseph; Joseph S. B. Mitchell; Cynthia A. Phillips; Steven S. Seiden

2002-01-01

402

Environmental flow allocation and statistics calculator  

USGS Publications Warehouse

The Environmental Flow Allocation and Statistics Calculator (EFASC) is a computer program that calculates hydrologic statistics based on a time series of daily streamflow values. EFASC will calculate statistics for daily streamflow in an input file or will generate synthetic daily flow series from an input file based on rules for allocating and protecting streamflow and then calculate statistics for the synthetic time series. The program reads dates and daily streamflow values from input files. The program writes statistics out to a series of worksheets and text files. Multiple sites can be processed in series as one run. EFASC is written in MicrosoftRegistered Visual BasicCopyright for Applications and implemented as a macro in MicrosoftOffice Excel 2007Registered. EFASC is intended as a research tool for users familiar with computer programming. The code for EFASC is provided so that it can be modified for specific applications. All users should review how output statistics are calculated and recognize that the algorithms may not comply with conventions used to calculate streamflow statistics published by the U.S. Geological Survey.

Konrad, Christopher P.

2011-01-01

403

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.

404

Moving kidney allocation forward: the ASTS perspective.  

PubMed

In 2008, the United Network for Organ Sharing issued a request for information regarding a proposed revision to kidney allocation policy. This plan described combining dialysis time, donor characteristics and the estimated life years from transplant (LYFT) each candidate would gain in an allocation score that would rank waiting candidates. Though there were some advantages of this plan, the inclusion of LYFT raised many questions. Foremost, there was no clear agreement that LYFT should be the main criterion by which patients should be ranked. Moreover, to rank waiting candidates with this metric, long-term survival models were required in which there was no incorporation of patient preference or discounting for long survival times and for which the predictive accuracy did not achieve accepted standards. The American Society of Transplant Surgeons was pleased to participate in the evaluation of the proposal. Ultimately, the membership did not favor this proposal, because we felt that it was too complicated and that the projected slight increase in overall utility was not justified by the compromise in individual justice that was required. We offer alternative policy options to address some of the unmet needs and issues that were brought to light during this interesting process. PMID:19519807

Freeman, R B; Matas, A T; Henry, M; Segev, D L; Kaufman, D B; Roberts, J P

2009-07-01

405

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

406

Impact of the lung allocation score.  

PubMed

The number of donors falls short of the number of patients on the wait list for lung transplantation making it necessary to ration the available donor organs. The ideal allocation system is guided by ethical principles and scientifically accurate at identifying patients who will gain the greatest degree of benefit from receiving the organ, in terms of both pre- and posttransplantation survival. The lung allocation score (LAS) was developed in 2005 to reduce mortality on the wait list, prioritize candidates based on urgency, minimize the role of geography, and maximize transplant benefit. The LAS has not made much of an impact on the geographic disparity of listing patients for lung transplantation, but it did achieve the goal of reducing wait-list mortality and prioritizing patients based on urgency. In prioritizing patients with the most urgent status, a new controversy has come into the forefront: whether or not the increased number of critically ill recipients maximizes transplant benefit. Despite the controversy, the LAS system is an improvement compared with the traditional first-come, first-served system, and it has even been adopted by Eurotransplant. In the future, as modifications are made to improve the LAS, the issue of critically ill patients and maximizing posttransplant benefit will be the focus. PMID:23821502

McShane, Pamela J; Garrity, Edward R

2013-06-01

407

An Efficient Bandwidth Allocation Strategy for Scale-Free Networks  

NASA Astrophysics Data System (ADS)

Traffic capacity is critical for various networks and strongly depends on the distribution of link's bandwidth resources. In this paper, we propose a betweenness-based bandwidth allocation strategy in which the bandwidth of each link lij is allocated proportionally to the product (1 + Bi)?(1 + Bj)?, where ? is a tunable parameter, and Bi and Bj are the betweenness of node i and node j, respectively. The optimal value of ? is achieved by extensive simulations and slightly increases with the network size. Our new bandwidth allocation strategy achieves the highest traffic capacity when compared with the average bandwidth allocation strategy and the previously proposed degree-based bandwidth allocation strategy. Our work will be beneficial for network service providers to improve the traffic capacity by efficiently allocating or reallocating the overall finite link's bandwidth resources of networks such as the Internet, urban transport networks and airway networks.

Jiang, Zhong-Yuan; Liang, Man-Gui; Zhang, Shuai; Wang, Shu-Juan; Guo, Dong-Chao

2012-10-01

408

Stochastic Evolution of General Systems.  

NASA Astrophysics Data System (ADS)

In this thesis we have investigated certain models pertaining to nonlinear stochastic systems. First of all, we have carried out a theoretical analysis of two nonlinear models of diffusion of information--one in a closed population (due to Bartholomew) and the other in an open population (due to Walls). These models involve nonlinearity of a quadratic nature and exhibit a cooperative behavior when a certain parameter d of the problem approaches a critical value d(,c). In the close vicinity of the critical point, the two models turn out to be quasi-isomorphic to each other. Impelled by this, the investigation is extended to a generalized model of which the Bartholomew model and the Walls model are special cases. A modified version of van Kampen's method of system-size expansion of the master equation of the process is employed for the stochastic analysis of the problem in the critical region of the process. This study establishes a broader class of systems displaying identical behavior in the critical region and also elucidates the role played by fluctuations in bringing about the cooperative phenomenon. Next, using the same method, we have investigated a class of nonlinear stochastic models with cubic interactions. The onset of a first-order phase transition in the system is investigated in detail. Besides studying some of the salient features of this model, we have also developed a recipe in the form of a Maxwell-like "theorem of equal areas" which answers a longstanding question as to when a general, real system with accessibility to multiple steady states will actually jump from one stable branch to another. Finally we have extended our study to a two-step, bivariate, nonlinear stochastic process, for which an even more generalized model of diffusion of information in a closed, homogeneously mixing population of size N is considered. The master equation for the model is set up and both deterministic and stochastic aspects of the stable, steady-state solutions of the problem are analyzed. Several existing models are retrieved as special cases. Certain new features of the process emerging from this generalization are discussed and a special model displaying critical behavior is outlined.

Sharma, Charan Lal

409

AESS: Accelerated Exact Stochastic Simulation  

NASA Astrophysics Data System (ADS)

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

Jenkins, David D.; Peterson, Gregory D.

2011-12-01

410

Topology-aware resource allocation for data-intensive workloads  

Microsoft Academic Search

This paper proposes an architecture for optimized resource allocation in Infrastructure-as-a-Service (IaaS)-based cloud systems. Current IaaS systems are usually unaware of the hosted application's requirements and therefore allocate resources independently of its needs, which can significantly impact performance for distributed data-intensive applications. To address this resource allocation problem, we propose an architecture that adopts a what if methodology to guide

Gunho Lee; Niraj Tolia; Parthasarathy Ranganathan; Randy H. Katz

2011-01-01

411

Metacognitive and control strategies in study-time allocation  

Microsoft Academic Search

This article investigates how people's metacognitive judgments influence subsequent study- time-allocation strategies. The authors present a comprehensive literature review indicating that people allocate more study time to.judged-difficult than to judged-easy items--consistent with extant models of study-time allocation. However, typically, the materials were short, and participants had ample time for study. In contrast, in Experiment 1, when participants had insufficient time

Lisa K. Son; Janet Metcalfe

2000-01-01

412

Climate Change and the Stability of Water Allocation Agreements  

Microsoft Academic Search

We analyse agreements on river water allocation between riparian countries. Besides being efficient, water allocation agreements\\u000a need to be stable in order to be effective in increasing the efficiency of water use. In this paper we assess the stability\\u000a of water allocation agreements using a game theoretic model. We consider the effects of climate change and the choice of a

Erik Ansink; Arjan Ruijs

2008-01-01

413

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

414

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

415

28 CFR 90.54 - Allocation of funds.  

Code of Federal Regulations, 2013 CFR

...Administration DEPARTMENT OF JUSTICE (CONTINUED) VIOLENCE AGAINST WOMEN Indian Tribal Governments Discretionary Program § 90.54 Allocation...account the applicants' varying needs in addressing violence against...

2013-07-01

416

Development of target allocation methods for LAMOST focal plate  

NASA Astrophysics Data System (ADS)

We first introduce the primary target allocation requirements and restrictions for the parallel control multiple fiber system, which is used in the LAMOST spectroscopic survey. The fiber positioner anti-collision model is imported. Then several target allocation methods and features are discussed in detail, including a network flow algorithm, high priority for fiber unit holding less target number, target allocation algorithm for groups, target allocation method for add-ons and target reallocation. Their virtues and weaknesses are analyzed for various kinds of scientific research situations. Furthermore an optimization concept using the Simulate Anneal Arithmetic (SAA) is developed to improve the fiber utilizing efficiency.

Yuan, Hailong; Zhang, Haotong; Zhang, Yanxia; Lei, Yajuan; Dong, Yiqiao

2014-01-01

417

Classification of boundary gravitons in AdS3 gravity  

NASA Astrophysics Data System (ADS)

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.

Garbarz, Alan; Leston, Mauricio

2014-05-01

418

A Study on Good PN Code Allocation for Position Oriented PN Code Allocation Scheme in DS\\/CDMA IVC  

Microsoft Academic Search

IVC(inter-vehicle communication) is one of the most important research topics in ITS (intelligent transport systems). In the IVC scheme using DS\\/CDMA (direct sequence\\/code division multiple access), allocation of PN codes is a major problem to be solved. In this paper, a good PN code allocation scheme for the DS\\/CDMA IVC system that allocates each PN code to the position on

Masahiro Kawabata; Shinichi Niihara; M. Itami; K. Itoh

2007-01-01

419

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

PubMed

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

Marrero-Ponce, Yovani; Martínez-Albelo, Eugenio R; Casañola-Martín, Gerardo M; Castillo-Garit, Juan A; Echevería-Díaz, Yunaimy; Zaldivar, Vicente Romero; Tygat, Jan; Borges, José E Rodriguez; García-Domenech, Ramón; Torrens, Francisco; Pérez-Giménez, Facundo

2010-11-01

420

Logarithmic AdS waves and Zwei-Dreibein gravity  

NASA Astrophysics Data System (ADS)

We show that the parameter space of Zwei-Dreibein Gravity (ZDG) in AdS3 exhibits critical points, where massive graviton modes coincide with pure gauge modes and new `logarithmic' modes appear, similar to what happens in New Massive Gravity. The existence of critical points is shown both at the linearized level, as well as by finding AdS wave solutions of the full non-linear theory, that behave as logarithmic modes towards the AdS boundary. In order to find these solutions explicitly, we give a reformulation of ZDG in terms of a single Dreibein, that involves an infinite number of derivatives. At the critical points, ZDG can be conjectured to be dual to a logarithmic conformal field theory with zero central charges, characterized by new anomalies whose conjectured values are calculated.

Bergshoeff, Eric A.; Goya, Andrés F.; Merbis, Wout; Rosseel, Jan

2014-04-01

421

All AdS7 solutions of type II supergravity  

NASA Astrophysics Data System (ADS)

In M-theory, the only AdS7 supersymmetric solutions are AdS7 × S 4 and its orbifolds. In this paper, we find and classify new supersymmetric solutions of the type AdS7 × M 3 in type II supergravity. While in IIB none exist, in IIA with Romans mass (which does not lift to M-theory) there are many new ones. We use a pure spinor approach reminiscent of generalized complex geometry. Without the need for any Ansatz, the system determines uniquely the form of the metric and fluxes, up to solving a system of ODEs. Namely, the metric on M 3 is that of an S 2 fibered over an interval; this is consistent with the Sp(1) R-symmetry of the holographically dual (1,0) theory. By including D8 brane sources, one can numerically obtain regular solutions, where topologically M 3 ? S 3.

Apruzzi, Fabio; Fazzi, Marco; Rosa, Dario; Tomasiello, Alessandro

2014-04-01

422

Gauged Kaluza-Klein AdS pseudo-supergravity  

NASA Astrophysics Data System (ADS)

We obtain the pseudo-supergravity extension of the D-dimensional Kaluza-Klein theory, which is the circle reduction of pure gravity in D+1 dimensions. The fermionic partners are pseudo-gravitino and pseudo-dilatino. The full Lagrangian is invariant under the pseudo-supersymmetric transformation, up to quadratic order in fermion fields. We find that the theory possesses a U(1) global symmetry that can be gauged so that all the fermions are charged under the Kaluza-Klein vector. The gauging process generates a scalar potential that has a maximum, leading to the AdS vacuum. Whist the highest dimension for gauged AdS supergravity is seven, our gauged AdS pseudo-supergravities can exist in arbitrary dimensions.

Liu, Haishan; Lü, H.; Wang, Zhao-Long

2011-09-01

423

Worldsheet scattering in AdS3/CFT2  

NASA Astrophysics Data System (ADS)

We confront the recently proposed exact S-matrices for AdS 3/ CFT 2 with direct worldsheet calculations. Utilizing the BMN and Near Flat Space (NFS) expansions for strings on AdS 3 × S 3 × S 3 × S 1 and AdS 3 × S 3 × T 4 we compute both tree-level and one-loop scattering amplitudes. Up to some minor issues we find nice agreement in the tree-level sector. At the one-loop level however we find that certain non-zero tree-level processes, which are not visible in the exact solution, contribute, via the optical theorem, and give an apparent mismatch for certain amplitudes. Furthermore we find that a proposed one-loop modification of the dressing phase correctly reproduces the worldsheet calculation while the standard Hernandez-Lopez phase does not. We also compute several massless to massless processes.

Sundin, Per; Wulff, Linus

2013-07-01

424

Internal markets and health care efficiency: a multiple-output stochastic frontier analysis.  

PubMed

This paper has two purposes. The first purpose is methodological and aims to extend previous work on efficiency analysis by implementing a multiple-output stochastic ray frontier production function model. This model generalizes the single-output stochastic frontier model to multiple-input, multiple-output technologies and allows simultaneous estimation of technical efficiency and analysis of influential variables on efficiency. The second, empirical, purpose is to test for existence and magnitude of the effect of purchaser/provider split combined with new reimbursement schemes on technical efficiency in the Swedish public hospital system. The analysis is carried out with a panel data set covering the total population of 26 Swedish County Councils from 1989 to 1995. Our empirical results support the frontier model specification and indicate that output-based reimbursement improves technical efficiency. The potential saving in costs due to a switch from budget-based allocation to output-based allocation is estimated to be almost 10%. PMID:10342728

Gerdtham, U G; Löthgren, M; Tambour, M; Rehnberg, C

1999-03-01

425

Cage allocation designs for rodent carcinogenicity experiments.  

PubMed

Cage allocation designs for rodent carcinogenicity experiments are discussed and presented with the goal of avoiding dosage group biases related to cage location. Considerations in selecting a cage design are first discussed in general terms. Specific designs are presented for use in experiments involving three, four, and five dose groups and with one, four, and five rodents per cage. Priorities for balancing treatment groups include horizontal position on shelf and shelf of rack, nearest neighbor balance, and male-female balance. It is proposed that these balance criteria be considered together with practical issues, such as the ability to accurately conform to a design and to determine a sensible and efficient design for each experiment. PMID:1295494

Herzberg, A M; Lagakos, S W

1992-07-01

426

Cage allocation designs for rodent carcinogenicity experiments.  

PubMed

Cage allocation designs for rodent carcinogenicity experiments are discussed and presented with the goal of avoiding dosage group biases related to cage location. Considerations in selecting a cage design are first discussed in general terms. Specific designs are presented for use in experiments involving three, four, and five dose groups and with one, four, and five rodents per cage. Priorities for balancing treatment groups include horizontal position on shelf and shelf of rack, nearest neighbor balance, and male-female balance. It is proposed that these balance criteria be considered together with practical issues, such as the ability to accurately conform to a design and to determine a sensible and efficient design for each experiment. PMID:17539183

Herzberg, A M; Lagakos, S W

1991-12-01

427

Intelligent initialization of resource allocating RBF networks.  

PubMed

In any neural network system, proper parameter initialization reduces training time and effort, and generally leads to compact modeling of the process under examination, i.e. less complex network structures and better generalization. However, in cases of multi-dimensional data, parameter initialization is both difficult and time consuming. In the proposed scheme a novel, multi-dimensional, unsupervised clustering method is used to properly initialize neural network architectures, focusing on resource allocating networks (RAN); both the hidden and output layer parameters are determined by the output of the clustering process, without the need for any user interference. The main contribution of this work is that the proposed approach leads to network structures that are compact, efficient and achieve best classification results, without the need for manual selection of suitable initial network parameters. The efficiency of the proposed method has been tested on several classes of publicly available data, such as iris, Wisconsin and ionosphere data. PMID:15795110

Wallace, Manolis; Tsapatsoulis, Nicolas; Kollias, Stefanos

2005-03-01

428

[Patient safety and nursing staff allocation].  

PubMed

This article aims to explore three main concepts related to the professional development of nursing professionals. This paper first critically reviews and reinterprets scientific evidence on the relationship between nurse staff allocation and healthcare outcomes and then challenges some of the common interpretations of this evidence in the professional literature. Secondly, in the absence of solid empirical evidence provided by sophisticated datasets in this field, we consider how Communitarianism may provide a well-defined, highly appropriate ethical framework for further developing and improving the nursing profession and healthcare outcomes. Thirdly, this article examines the role of Communitarian ethics in setting Taiwan's healthcare priorities and promotion nursing's core professional values. In conclusion, we recommend several conceptual health policy frameworks to ensure patient safety. PMID:23588690

Lee, Jwo-Leun; Chi, Chunhuei; Hsu, Ming-Yi

2013-04-01

429

Vehicle routing problem in investment fund allocation  

NASA Astrophysics Data System (ADS)

Since its introduction by Dantzig and Ramser in 1959, vehicle routing problem keeps evolving in theories, applications and variability. The evolution in computing and technology are also important contributors to research in solving vehicle routing problem. The main sectors of interests among researchers and practitioners for vehicle routing problem are transportation, distribution and logistics. However, literature found that concept and benefits of vehicle routing problem are not taken advantages of by researchers in the field of investment. Other methods found used in investment include multi-objective programming, linear programming, goal programming and integer programming. Yet the application of vehicle routing problem is not fully explored. A proposal on a framework of the fund allocation optimization using vehicle routing problem is presented here. Preliminary results using FTSE Bursa Malaysia data testing the framework are also given.

Mamat, Nur Jumaadzan Zaleha; Jaaman, Saiful Hafizah; Ahmad, Rokiah Rozita; Mohd, Ismail

2013-04-01

430

Adolescence, attention allocation, and driving safety.  

PubMed

Motor vehicle crashes are the leading source of morbidity and mortality in adolescents in the United States and the developed world. Inadequate allocation of attention to the driving task and to driving hazards are important sources of adolescent crashes. We review major explanations for these attention failures with particular focus on the roles that brain immaturity and lack of driving experience play in causing attention problems. The review suggests that the potential for overcoming inexperience and immaturity with training to improve attention to both the driving task and hazards is substantial. Nevertheless, there are large individual differences in both attentional abilities and risky driving tendencies that pose challenges to novice driver policies. Research that can provide evidence-based direction for such policies is urgently needed. PMID:24759442

Romer, Daniel; Lee, Yi-Ching; McDonald, Catherine C; Winston, Flaura K

2014-05-01

431

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

432

Allocation of Wealth and Emergence of Inequality  

NASA Astrophysics Data System (ADS)

Though socioeconomic inequality has always been a classic subject of study in sociology and finance, it has caught the attention of many physicists in the last decade. The application of kinetic theory of gases to study the emergence of wealth distributions continues to develop itself as a new field of applications of statistical physics. The challenge for physicists is to identify basic microscopic interactions among individuals, namely trading and investment, which rule the macroscopic statistics of the system of individuals as a whole. Several models have been elaborated and certain microscopic parameters were identified as vital for the existence of statistically different wealth distributions. We present a model which considers different savings propensities, stochastic nature of trades and investments, and explore specific choices of micro-trading parameters which produce qualitatively different wealth distributions like those of the United States and Australia.

Romero, Natalia; Wille, Luc

2010-03-01

433

Allocation or misallocation of limited medical resources.  

PubMed

Very small premature babies are now kept in neonatal intensive care units for many months to give them a chance at near normal life, but at a cost of up to dollars 1 million. Is that a proper allocation of our finite medical resources (personnel, equipment, supplies, and other necessities) for premies? Or is such action a misallocation of these resources? Both sides of the argument have positive and negative merit. A final philosophical statement is that each human created in the image of God has supreme value. It is it the obligation of fellow humans and society in general to preserve and dignify human life and to care for the total needs of individual citizens to enable them to be healthy and productive members of society. This general principle should help individual physicians make proper microallocation life and death decisions for individual patients and assist governmental bodies responsible for making macroallocation decisions concerning the short- and long-term needs and priorities of the population as a whole. All such decisions should be guided by the basic ethical principles of beneficence, nonmaleficence, autonomy, and justice. However, these principles may at times conflict. For example, if the autonomous rights of the patient conflict with the justice appeals of the community or if beneficence to an individual patient conflict with the needs of another patient, can we deny health care services? By what criteria (merit, potential, effort, achievement, age)? These are difficult if not impossible questions to answer, but they pertain to the topic of this commentary on the allocation of limited medical resources, which is meant to raise the sensitivity of the reader to the complexity of the problem and to raise ethical questions, which are not easily answered or dealt with. PMID:15581061

Rosner, Fred

2004-01-01

434

Stochastic solution to quantum dynamics  

NASA Astrophysics Data System (ADS)

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.

1994-02-01

435

Stochastic assessment of multiple illuminations  

NASA Astrophysics Data System (ADS)

Stochastic assessment of multiple illuminations (SAMI) is a quantifiably robust hand calculator model which uses applied probability theory to yield the mean and standard deviation of beam-on-beam illumination events for a target located in an active threat sensor environment. The electromagnetic wave front arrival model predicts simultaneous illuminations of a target by using the mechanical properties of a radar type as inputs into a mathematically defensible and situation sensitive formula. The SAMI methodology can be recursively applied to yield the same results for pulse-on-pulse occurrences within the beam-on-beam events.

Love, Newton, Jr.

436

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

437

Stochastic Gravity: Theory and Applications  

NASA Astrophysics Data System (ADS)

Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of the stress-energy tensor of quantum fields, stochastic semiclassical gravity is based on the Einstein-Langevin equation, which has in addition sources due to the noise kernel. The noise kernel is the vacuum expectation value of the (operator-valued) stress-energy bi-tensor which describes the fluctuations of quantum matter fields in curved spacetimes. In the first part, we describe the fundamentals of this new theory via two approaches: the axiomatic and the functional. The axiomatic approach is useful to see the structure of the theory from the framework of semiclassical gravity, showing the link from the mean value of the stress-energy tensor to their correlation functions. The functional approach uses the Feynman-Vernon influence functional and the Schwinger-Keldysh closed-time-path effective action methods which are convenient for computations. It also brings out the open systems concepts and the statistical and stochastic contents of the theory such as dissipation, fluctuations, noise, and decoherence. We then focus on the properties of the stress-energy bi-tensor. We obtain a general expression for the noise kernel of a quantum field defined at two distinct points in an arbitrary curved spacetime as products of covariant derivatives of the quantum field's Green function. In the second part, we describe three applications of stochastic gravity theory. First, we consider metric perturbations in a Minkowski spacetime. We offer an analytical solution of the Einstein-Langevin equation and compute the two-point correlation functions for the linearized Einstein tensor and for the metric perturbations. Second, we discuss structure formation from the stochastic gravity viewpoint, which can go beyond the standard treatment by incorporating the full quantum effect of the inflaton fluctuations. Third, we discuss the backreaction of Hawking radiation in the gravitational background of a quasi-static black hole (enclosed in a box). We derive a fluctuation-dissipation relation between the fluctuations in the radiation and the dissipative dynamics of metric fluctuations.

Hu, Bei Lok; Verdaguer, Enric

2004-03-01

438

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

439

Stochastic dynamics on slow manifolds  

NASA Astrophysics Data System (ADS)

The theory of slow manifolds is an important tool in the study of deterministic dynamical systems, giving a practical method by which to reduce the number of relevant degrees of freedom in a model, thereby often resulting in a considerable simplification. In this paper we demonstrate how the same basic methodology may also be applied to stochastic dynamical systems, by examining the behaviour of trajectories conditioned on the event that they do not depart the slow manifold. We apply the method to two models: one from ecology and one from epidemiology, achieving a reduction in model dimension and illustrating the high quality of the analytical approximations.

Constable, George W. A.; McKane, Alan J.; Rogers, Tim

2013-07-01

440

Phase Description of Stochastic Oscillations  

NASA Astrophysics Data System (ADS)

We introduce an invariant phase description of stochastic oscillations by generalizing the concept of standard isophases. The average isophases are constructed as sections in the state space, having a constant mean first return time. The approach allows us to obtain a global phase variable of noisy oscillations, even in the cases where the phase is ill defined in the deterministic limit. A simple numerical method for finding the isophases is illustrated for noise-induced switching between two coexisting limit cycles, and for noise-induced oscillation in an excitable system. We also discuss how to determine isophases of observed irregular oscillations, providing a basis for a refined phase description in data analysis.

Schwabedal, Justus T. C.; Pikovsky, Arkady

2013-05-01

441

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

442

Deterministic and stochastic bifurcations in the Hindmarsh-Rose neuronal model  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

443

Towards Optimal Allocation of Computer Resources: Trade-offs between Uncertainty, Discretization and Model Reduction  

NASA Astrophysics Data System (ADS)

In recent years, there has been an increase in the computational complexity of hydro(geo)logical models. This has been driven by new problems addressing large-scale relationships like global warming, reactive transport on the catchment scale or CO2 sequestration. Computational model complexity becomes even more drastic, when facing the ubiquitous need for uncertainty quantification and risk assessment in the environmental sciences. Computational complexity can be broken down into contributions ranging from spatial, temporal and stochastic resolution, e.g., spatial grid resolution, time step size and number of repeated simulations dedicated to quantify uncertainty. Controlling these resolutions allows keeping the computational cost at a tractable level whilst guaranteeing accurate and robust predictions. Having this possibility at hand triggers our overall driving question: What is the optimal resolution for independent variables (i.e. time and space) to achieve reliable prediction in the presence of uncertainty? Can we determine an overall optimum combination of the number of realizations, spatial and temporal resolutions, needed for overall statistical/physical convergence of model predictions? If so, how can we find it? In other words, how can we optimally allocate available computational resources in order to achieve highest accuracy associated with a given prediction goal? In this work, we present an approach that allows to determine the compromise among different model dimensions (space, time, probability) when allocating computational resources. The overall goal is to maximize the prediction accuracy given limited computational resources. Our analysis is based on the idea to jointly consider the discretization errors and computational costs of all individual model dimensions. This yields a cost-to-error surface which serves to aid modelers in finding an optimal allocation of the computational resources. As a pragmatic way to proceed, we propose running small cost-efficient pre-investigations in order to estimate the joint cost-to-error surface and fit underlying complexity and error models, then decide upon a design for the setup of the full simulation, and finally to perform the designed simulations at near-optimal costs. We illustrate our concept with two examples from subsurface hydrogeology (wetland management and pump-and-treat remediation) and show that the computational costs can be reduced when allocating computational resources wisely. In the two featured examples, the best ratio between spatial resolution and the number of Monte-Carlo realizations is surprising. In comparison to existing recommendations found in the literature, the ratio far on the side of fine discretization and suggests only a small number of Monte-Carlo repetitions.

Nowak, W.; Leube, P.; Zinkhahn, M.; de Barros, F.; Rajagopal, R.

2012-12-01

444

Comparing administered and market-based water allocation systems using an agent-based modeling approach  

NASA Astrophysics Data System (ADS)

It also has been well recognized that market-based systems can have significant advantages over administered systems for water allocation. However there are not many successful water markets around the world yet and administered systems exist commonly in water allocation management practice. This paradox has been under discussion for decades and still calls for attention for both research and practice. This paper explores some insights for the paradox and tries to address why market systems have not been widely implemented for water allocation. Adopting the theory of agent-based system we develop a consistent analytical model to interpret both systems. First we derive some theorems based on the analytical model, with respect to the necessary conditions for economic efficiency of water allocation. Following that the agent-based model is used to illustrate the coherence and difference between administered and market-based systems. The two systems are compared from three aspects: 1) the driving forces acting on the system state, 2) system efficiency, and 3) equity. Regarding economic efficiency, penalty on the violation of water use permits (or rights) under an administered system can lead to system-wide economic efficiency, as well as being acceptable by some agents, which follows the theory of the so-call rational violation. Ideal equity will be realized if penalty equals incentive with an administered system and if transaction costs are zero with a market system. The performances of both agents and the over system are explained with an administered system and market system, respectively. The performances of agents are subject to different mechanisms of interactions between agents under the two systems. The system emergency (i.e., system benefit, equilibrium market price, etc), resulting from the performance at the agent level, reflects the different mechanism of the two systems, the “invisible hand” with the market system and administrative measures (penalty and subsidy) with the administered system. Furthermore, the impact of hydrological uncertainty on the performance of water users under the two systems is analyzed by extending the deterministic model to a stochastic one subject to the uncertainty of water availability. It is found that the system response to hydrologic uncertainty depends on risk management mechanics - sharing risk equally among the agents or by prescribed priorities on some agents. Figure1. Agent formulation and its implications in administered system and market-based system

Zhao, J.; Cai, X.; Wang, Z.

2009-12-01

445

An Overlapping Networks Approach to Resource Allocation for Domestic Counterterrorism  

Microsoft Academic Search

Motivated by the links between terror and crime and the difficulty in directly detecting terror activity, this article formulates and solves a resource allocation problem on overlapping networks to determine if interdiction efforts may be able to take advantage of these connections. The government, knowing only the general structure and overlap of the networks, allocates its scarce resources to investigate

Michael P. Atkinson; Lawrence M. Wein

2010-01-01

446

Program-based static allocation policies for highly parallel computers  

Microsoft Academic Search

Static space sharing is a promising processor allocation strategy for highly-parallel computers. Parallel jobs or tasks are allocated fixed distinct subsets of processors. Thread scheduling can be carried out directly by the applications so as to reduce its cost, interference among jobs is reduced, and a wide range of compiler and runtime optimizations, including static data distribution and binding, are

Ismail M. Ismail; James A. Davis

1995-01-01

447

Federalism and optimal allocation across levels of governance  

Microsoft Academic Search

Countries differ in their governmental architectures and in the rules that describe the allocation of tasks, rights and duties across the various levels of government. In this paper, we present a short and selective survey of the development of the theory of optimal allocation of rights and duties along the vertical dimension in federations. We thereby first discuss the multiple

Benny Geys; Kai A. Konrad

2010-01-01

448

Optimal allocation of resources in distributed information networks  

Microsoft Academic Search

The problems of file allocation and capacity assignment in a fixed topology distributed computer network are examined. These two aspects of the design are tightly coupled through an average message delay constraint. The objective is to allocate copies of information files to network nodes and capacities to network links so that a minimum cost is achieved subject to network delay

Samy A. Mahmoud; J. Spruce Riordon

1975-01-01

449

Optimal allocation of resources in distributed information networks  

Microsoft Academic Search

The problems of file allocation and capacity assignment in a fixed topology distributed computer network are examined. These two aspects of the design are tightly coupled by means of an average message delay constraint. The objective is to allocate copies of information files to network nodes and capacities to network links so that a minimum cost is achieved subject to

Samy A. Mahmoud; J. Spruce Riordon

1976-01-01

450

Characterizing Contract-Based Multiagent Resource Allocation in Networks  

Microsoft Academic Search

We consider a multiagent resource allocation problem where individual users intend to route traffic by requesting the help of entities across a network, and a cost is incurred at each network node that depends on the amount of traffic to be routed. We propose to study contract-based network resource allocation. In our model, users and nodes in the network make

Bo An; Victor R. Lesser

2010-01-01

451

Joint Scheduling and Resource Allocation in CDMA Systems  

Microsoft Academic Search

We consider scheduling and resource allocation for the downlink in a CDMA based wireless network. The scheduling and resource allocation problem is to select a subset of the users for transmission and for each of the users selected, to choose the modulation and coding scheme, transmission power, and number of codes used. We refer to this combination as the physical

Rajeev Agrawal; Vijay Subramanian; Randall Berry

2004-01-01

452

The priority-based coloring approach to register allocation  

Microsoft Academic Search

Global register allocation plays a major role in determining the efficacy of an optimizing compiler. Graph coloring has been used as the central paradigm for register allocation in modern compilers. A straightforward coloring approach can suffer from several shortcomings. These shortcomings are addressed in this paper by coloring the graph using a priority ordering. A natural method for dealing with

Fred C. Chow; John L. Hennessy

1990-01-01

453

Power-control-based band allocation in multiband CDMA  

Microsoft Academic Search

Multiband CDMA is useful for constructing DS-CDMA (CDMA) systems over a non-contiguous spectrum. The method by which users are assigned to their respective frequency bands, termed 'band allocation', is an important part of assuring good performance in multiband CDMA systems. This paper proposes a novel approach to band allocation based on the transmission power as it is adjusted by power

Brooke E. Shrader; Robert S. Karlsson; Lachlan L. H. Andrew; Jens Zander

2001-01-01

454

Knowledge-based allocation model for distributed processing systems  

Microsoft Academic Search

The authors propose a model for a knowledge-based assistant (expert system) to aid in allocating a blackboard-oriented system to a multiprocessor or distributed platform. It incorporates variants of several important techniques of artificial intelligence to provide recommendations for the allocation of a set of knowledge sources to a set of processors. To provide intelligent recommendations, an expert system acquires the

Sanja VraneS; P. Subasic

1993-01-01

455

47 CFR 2.106 - Table of Frequency Allocations.  

Code of Federal Regulations, 2010 CFR

...non-Federal Table.)NG1The band 535-1705 kHz is also allocated...authorized frequencies in the band 72-73 and 75.4-76 MHz on the...Allocations.NG5In the band 535-1705 kHz, AM broadcast...purposes. In the bands 54-72, 76-88, 174-216,...

2012-10-01

456

Resource Allocation for Distributed Cloud: Concepts and Research Challenges  

Microsoft Academic Search

In a cloud computing environment, dynamic resource allocation and reallocation are keys for accommodating unpredictable demands and, ultimately, contribute to investment return. This article discusses this process in the context of distributed clouds, which are seen as systems where application developers can selectively lease geographically distributed resources. This article highlights and categorizes the main challenges inherent to the resource allocation

Patricia Takako Endo; Andre Vitor de Almeida Palhares; Nadilma Cintra Valenca Nunes Pereira; Glauco Estacio Goncalves; Djamel Fawzi Hadj Sadok; Judith Kelner; Bob Melander; Jan-Erik Mangs

2011-01-01

457

Flexible resource allocation for reliable virtual cluster computing systems  

Microsoft Academic Search

Virtualization and cloud computing technologies now make it possible to create scalable and reliable virtual high performance computing clusters. Integrating these technologies, however, is complicated by fundamental and inherent differences in the way in which these systems allocate resources to computational tasks. Cloud computing systems immediately allocate available resources or deny requests. In contrast, parallel computing systems route all requests

Thomas J. Hacker; Kanak Mahadik

2011-01-01

458

A time-driven adaptive mecahnism for cloud resource allocation  

Microsoft Academic Search

In this paper, we propose using adaptive allocation to find the most appropriate data center and physical machine for both users and service providers in a cloud computing environment. The proposed model adaptively finds the proper data center for the user based on expected allocation time and location. For the provider, the proposed model considers the workload of physical machines

Gihun Jung; Kwang Mong Sim; Paul C. K. Kwok; Minjie Zhang

2011-01-01

459

A Framework for Resource Allocation Strategies in Cloud Computing Environment  

Microsoft Academic Search

This paper presents a critical evaluation of current network resource allocation strategies and their possible applicability in Cloud Computing Environment which is expected to gain a prominent profile in the Future Internet. This research attempts to focus towards network awareness and consistent optimization of network resource allocation strategies and identifies the issues which need further investigation by the research community.

M. Asad Arfeen; Krzysztof Pawlikowski; Andreas Willig

2011-01-01

460

45 CFR 400.319 - Allocation of funds.  

Code of Federal Regulations, 2013 CFR

...assistance county may allocate its targeted assistance funds differently from the formula allocations for counties presented in the ORR targeted assistance notice in a fiscal year only on the basis of its population of refugees who arrived in the U.S....

2013-10-01

461

Student Project Allocation with Preference Lists over (Student, Project) Pairs  

Microsoft Academic Search

Student project allocations models (SPA) in which lecturers have preferences over students (projects) have been studied in. We present new method to construct a general student project allocation model (SPA-(s, p)) in which the lecturers have preference lists over pairs (student, project), and the students have preference lists over projects. SPA-(s, p) is turned out to be very useful in

Ahmed H. Abu El-Atta; M. I. Moussa

2009-01-01

462

DEVELOPMENT AND IMPROVEMENT OF TEMPORAL ALLOCATION FACTOR FILE  

EPA Science Inventory

The paper discusses a project to evaluate the quality and completeness of data and methods being used for temporal allocation of emissions data, to identify and prioritize needed improvements to current methods for developing temporal allocation factors, and to collect and use da...

463

Higher Education Cooperation Act: Fiscal Year 1998 Grant Allocations.  

ERIC Educational Resources Information Center

This report describes fiscal year 1998 grant allocations made under the Illinois Higher Education Cooperation Act (HECA) to support programs and projects involving cooperation among higher education institutions. A total of $16.59 million was allocated. Projects recommended for grant funds include 3 new and 12 continuing interinstitutional…

Illinois State Board of Higher Education, Springfield.

464

43 CFR 4610.4-3 - Allocation of funds appropriated.  

Code of Federal Regulations, 2010 CFR

...INTERIOR RANGE MANAGEMENT (4000) LEASES OF GRAZING LAND-PIERCE ACT Procedures § 4610.4-3 Allocation of funds appropriated...Moneys received in the administration of lands leased under the Pierce Act, when appropriated by the Congress, will be allocated...

2009-10-01

465

43 CFR 4610.4-3 - Allocation of funds appropriated.  

Code of Federal Regulations, 2010 CFR

...INTERIOR RANGE MANAGEMENT (4000) LEASES OF GRAZING LAND-PIERCE ACT Procedures § 4610.4-3 Allocation of funds appropriated...Moneys received in the administration of lands leased under the Pierce Act, when appropriated by the Congress, will be allocated...

2010-10-01

466

43 CFR 4610.4-3 - Allocation of funds appropriated.  

Code of Federal Regulations, 2013 CFR

...INTERIOR RANGE MANAGEMENT (4000) LEASES OF GRAZING LAND-PIERCE ACT Procedures § 4610.4-3 Allocation of funds appropriated...Moneys received in the administration of lands leased under the Pierce Act, when appropriated by the Congress, will be allocated...

2013-10-01

467

Optimal capacity allocation for load balanced shortest path routing  

Microsoft Academic Search

In this paper we first describe the load balanced shortest path routing (LB-SPR) protocol. Then, we present the linear program for the optimal capacity allocation, to minimize the resource consumption when LB-SPR is applied in the network. We show that when the load balancing is applied, the capacity allocation problem can be expressed only in terms of the total traffic

Marija Antic; Aleksandra Smiljanic

2009-01-01

468

Bilevel allocation-location model for state owned reserve warehouse  

Microsoft Academic Search

With the development of global economy, it is important for a nation to build new or reorganize original state owned reserve warehouse to store strategic energy resources in case of emergency, among which locating where to place is now becoming the most critical one. In this paper, we formulate a bilevel allocation-location model with bias policy taking allocation decision, location

Jingzhi Ding; Jianxiao Xu; Loo Hay Lee; Ek Peng Chew

2008-01-01

469

Global Warming and Water Management: Water Allocation and Project Evaluation  

Microsoft Academic Search

This paper explores the sensitivity of the benefits of alternative water allocation schemes and of project evaluation to global warming. If global warming shifts the mean of annual water supplies, there could be large impacts on the expected values of alternative water allocation schemes. The first section of the paper explores how well alternative schemes (such as market mechanisms, prior

Robert Mendelsohn; Lynne L. Bennett

1997-01-01

470

Using Cyclic Memory Allocation to Eliminate Memory Leaks.  

National Technical Information Service (NTIS)

We present and evaluate a new memory management technique for eliminating memory leaks in programs with dynamic memory allocation. This technique observes the execution of the program on a sequence of training inputs to find m-bounded allocation sites, wh...

H. H. Nguyen M. Rinard

2005-01-01

471

Multi-UAV Task Allocation using Team Theory  

Microsoft Academic Search

A multiple UAV search and attack mission in a battlefield involves allocating UAVs to different target tasks efficiently. This task allocation becomes difficult when there is no communication among the UAVs and the UAVs sensors have limited range to detect the targets and neighbouring UAVs, and assess target status. In this paper, we propose a team theoretic approach to efficiently

P. B. Sujit; A. Sinha; D. Ghose

2005-01-01

472

Fixed cost allocation and the constrained product mix decision  

Microsoft Academic Search

This paper focuses on the benefits of fixed cost allocation in product mix decisions. We show that in a constrained production environment where at least one factor of production is fixed and in short supply, oligopoly firms can earn higher profits by allocating the costs of these fixed factors The higher profits occur because the use of full absorption product

Susan Haka; Fred Jacobs; Ronald Marshall

2002-01-01

473

Allocating the Materials Funds Using Total Cost of Materials.  

ERIC Educational Resources Information Center

Discusses the need at the University of Southern Mississippi library to review resource allocations among serials, monographs and standing orders, and to select an allocation formula. The supply and demand formula used, its implementation, and results in departmental purchasing power are described. (four references) (EA)

Cubberley, Carol

1993-01-01

474

Resource-dependent sex-allocation in a simultaneous hermaphrodite  

Microsoft Academic Search

Most sex allocation theory is based on the relationship between the resource investment into male and female reproduction and the consequent fitness returns (often called fitness-gain curves). Here we investigate the effects of resource availability on the sex allocation of a simultaneously hermaphroditic animal, the free-living flatworm Macrostomum lignano. We kept the worms under different resource levels and determined the

D. B. VIZOSO; L. SCHÄRER

2007-01-01

475

Capacity Choice and Allocation: Strategic Behavior and Supply Chain Performance  

Microsoft Academic Search

We consider a simple supply chain in which a single supplier sells to several downstream retailers. The supplier has limited capacity, and retailers are privately informed of their optimal stocking levels. If retailer orders exceed available capacity, the supplier allocates capacity using a publicly known allocation mechanism, a mapping from retailer orders to capacity assignments. We show that a broad

Gérard P. Cachon; Martin A. Lariviere

1999-01-01

476

Scarcity, Conflict, and Equity in Allocating Public Recreation Resources.  

ERIC Educational Resources Information Center

The conflict between the interests of commercial outfitters and private boaters in the use of whitewater rivers is examined. A discussion is presented on the literature on scarcity, allocation, and conflict among groups. These concepts are applied to the allocation of public resources on whitewater rivers. The conflicting interest groups are…

Shelby, Bo; Danley, Mark

477

DISTRIBUTION NETWORK LOSS ALLOCATIONS WITH DISTRIBUTED GENERATION USING NODAL PRICES  

Microsoft Academic Search

We propose employing nodal factor pricing, a method as- sociated with allocating losses at EHV transmission lev- els, for the allocation of loss costs at the distribution level. This method differs from traditional methods of averag- ing losses across customers regardless of location, time of use, or the marginal contribution of net power injec- tion\\/withdrawal positions to losses. With respect

J. Mario Vignolo; Paul M. Sotkiewicz

478

Allocation of fixed costs in distribution networks with distributed generation  

Microsoft Academic Search

In this paper, we propose a method for the allocation of fixed (capital and nonvariable operation and maintenance) costs at the medium voltage (MV) distribution level. The method is derived from the philosophy behind the widely used MW-mile methodology for transmission networks that bases fixed cost allocations on the \\

Paul M. Sotkiewicz; J. Mario Vignolo

2006-01-01

479

Function allocation: a perspective from studies of work practice  

Microsoft Academic Search

Function allocation is a central component of systems engineering and its main aim is to provide a rational means of determining which system-level functions should be carried out by humans and which by machines. Such allocation it is assumed can take place early in design life cycle. Such a rational approach to work design sits uneasily with studies of work

Peter C. Wright; Andy Dearden; Bob Fields

2000-01-01

480

Birth Order and the Intrahousehold Allocation of Time and Education  

Microsoft Academic Search

This paper develops a model of intrahousehold allocation with endogenous fertility, which captures the relationship between birth order and investment in children. It shows that a birth order effect in intrahouse hold allocation can arise even without assumptions about parental preferences for specific birth orders of children or genetic endowments varying by birth order. The important contribution is that fertility

Mette Ejrnaes; Claus C. Pörtner

2004-01-01

481

Implementing optimal allocation for sequential continuous responses with multiple treatments  

Microsoft Academic Search

In practice, it is important to find optimal allocation strategies for continuous response with multiple treatments under some optimization criteria. In this article, we focus on exponential responses. For a multivariate test of homogeneity, we obtain the optimal allocation strategies to maximize power while (1) fixing sample size and (2) fixing expected total responses. Then the doubly adaptive biased coin

Hongjian Zhu; Feifang Hu

2009-01-01

482

Inter-store externalities and space allocation in shopping centers  

Microsoft Academic Search

This article analyzes the problem of optimal space allocation in shopping centers in the presence of inter-store externalities. In the model, a given store's sales depend on its own space as well as on the space allocated to other stores in the center. The given stores' own sales rise as other stores grow in size because the shopping center is

Jan K. Brueckner

1993-01-01

483

Resource Allocation Strategies Employed in Large versus Small School Systems.  

ERIC Educational Resources Information Center

Education is faced with a declining resource base coupled with overwhelming demands for categorical programs. The current resource allocation strategy common to all systems is cutting spending. The difference between large and small districts is less important than differences in complexity. Complexity in resource allocations is more a function of…

Gutierrez, Eugene J.

484

Distributed resource allocation for network-supported FGS video streaming  

Microsoft Academic Search

In this paper, we propose a novel distributed resource allocation algorithm for fine granularity scalable video streaming. Our system model includes a proxy-based network infrastructure that is used for allocating locally the available bandwidth between the video rate and error control. Initially, we express analytically the expected decoder distortion as a function of both the source video streaming rate and

Antonios Argyriou

2007-01-01

485

Multi-agent resource allocation for road passenger transportation?  

Microsoft Academic Search

Inter-urban road passenger transportation requires the allo- cation of drivers and buses to transport people. In such allocation pro- cess, several constraints on driving time are being imposed by the gov- ernments in order to assure citizens safety. Such constraints, however, are posing a lot of di-culties to the allocation process, usually generated by human operators. In this paper we

Beatriz Lopez; Pere Urra; Xavier Abello

486

Effects of Resource Allocation Policies on Project Durations  

Microsoft Academic Search

Minimizing duration is critical to success in many construction projects. As a primary driver of progress and an effective management tool, resource allocation among development activities can strongly influence durations. Limitations and costs of improving development processes and increasing resource quantities and productivities make improving resource allocation policies an important source of schedule improvement. Policies for reduced project duration are

Zee Woon Lee; David N. Ford; Nitin Joglekar

487

Inequalities and strong laws of large numbers for random allocations  

Microsoft Academic Search

Moment inqualities and strong laws of large numbers are proved for random allocations of balls into boxes. Random broken lines and random step lines are constructed using partial sums of i.i.d. random variables that are modified by random allocations. Functional limit theorems for such random processes are obtained.

Alexey Chuprunov; István Fazekas

2005-01-01

488

Optimal power allocation over parallel Gaussian broadcast channels  

Microsoft Academic Search

We analyze the problem of communication over a set of parallel Gaussian broadcast channels, each with a different set of noise power for the users. We show that capacity can be achieved by optimal power allocation over the channels, and obtain an explicit characterization of the optimal power allocations and the resulting capacity region

David N. C. Tse

1997-01-01

489

Downlink Power Allocation for Stored Variable-Bit-Rate Videos  

Microsoft Academic Search

In this paper, we study the problem of power allocation for streaming multiple variable-bit-rate (VBR) videos in the downlink of a cellular network. We consider a deterministic model for VBR video traffic and finite playout buffer at the mobile users. The objective is to derive the optimal downlink power allocation for the VBR video sessions, such that the video data

Yingsong Huang; Shiwen Mao; Yihan Li

2011-01-01

490

A determination method of product allocation schedule for warehouse management  

Microsoft Academic Search

The warehousing system consists of several storage space, pallets and overhead crane conveying the products. Due to the complexity of the movements of the products in warehousing system, it is difficult to obtain a reasonable schedule for product allocation. In this paper, we propose a determination method for product allocation schedule in automated warehousing system by using the simulation-based optimization

H. Takahama; T. Nishi; M. Konishi; J. Imai

2002-01-01

491

On the Allocation of Resources for Secondary Schools  

ERIC Educational Resources Information Center

This paper studies the optimal allocation of resources--in terms of school management, teachers, supporting employees and materials--in secondary schools. We use a flexible budget constrained output distance function model to estimate both technical and allocative efficiency scores for 448 Dutch secondary schools between 2002 and 2007. The results…

Haelermans, Carla; De Witte, Kristof; Blank, Jos L. T.

2012-01-01

492

Allocating Uncertain and Unresponsive Resources: An Experimental Approach  

Microsoft Academic Search

We identify an important class of economic problems that arise naturally in several applications: the allocation of multiple resources when there are uncertainties in demand or supply, unresponsive supplies (no inventories and fixed capacities), and significant demand indivisibilities (rigidities). Examples of such problems include: scheduling job shops, airports, or supercomputers; zero-inventory planning; and the allocation and pricing of NASA's planned

Jeffrey S. Banks; John O. Ledyard; David P. Porter

1989-01-01

493

Dynamic versus static allocation policies in multipurpose multireservoir systems  

Microsoft Academic Search

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

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

2007-01-01

494

The Effect of Student Time Allocation on Academic Achievement  

ERIC Educational Resources Information Center

There is a large literature on the influence of institutional characteristics on student academic achievement. In contrast, relatively little research focusses on student time allocation and its effects on student performance. This paper contributes to the literature by investigating the effect of student time allocation on the average grade of…

Grave, Barbara S.

2011-01-01

495

Analysis of Dynamic Task Allocation in Multi-Robot Systems  

Microsoft Academic Search

Dynamic task allocation is an essential requirement for multi-robot systems functioning in unknown dynamic environments. It allows robots to change their behavior in response to environmental changes or actions of other robots in order to improve overall system performance. Emergent coordination algorithms for task allocation that use only local sensing and no direct communication between robots are attractive because they

Kristina Lerman; Chris Jones; Aram Galstyan; Maja J. Mataric

2006-01-01

496

Study on pilot attention allocation model based on fuzzy theory  

Microsoft Academic Search

Quantitative research of pilot attention allocation mechanism is required in aircraft human-machine interface optimization design and pilot flight performance evaluation. After making a comprehensive consideration of several factors, including information importance, information visual coding, information processing depth and human errors, pilot attention allocation model based on fuzzy theory is built. In order to make verification of this model, a head-up

Xiaoru Wanyan; Hengyang Wei; Damin Zhuang

2010-01-01

497

WCET-Directed Dynamic Scratchpad Memory Allocation of Data  

Microsoft Academic Search

Many embedded systems feature processors coupled with a small and fast scratchpad memory. To the difference with caches, allocation of data to scratchpad memory must be handled by software. The major gain is to enhance the pre- dictability of memory accesses latencies. A compile-time dy- namic allocation approach enables eviction and placement of data to the scratchpad memory at runtime.

Jean-françois Deverge; Isabelle Puaut

2007-01-01

498

Resource Allocation Models and Accountability: A Jamaican Case Study  

ERIC Educational Resources Information Center

Higher education institutions (HEIs) may be funded privately, by the state or by a mixture of the two. Nevertheless, any state financing of HE necessitates a mechanism to determine the level of support and the channels through which it is to be directed; that is, a resource allocation model. Public funding, through resource allocation models,…

Nkrumah-Young, Kofi K.; Powell, Philip

2008-01-01

499

Lung and heart allocation in the United States.  

PubMed

Lung and heart allocation in the United States has evolved over the past 20-30 years to better serve transplant candidates and improve organ utilization. The current lung allocation policy, based on the Lung Allocation Score, attempts to take into account risk of death on the waiting list and chance of survival posttransplant. This policy is flexible and can be adjusted to improve the predictive ability of the score. Similarly, in response to the changing clinical phenotype of heart transplant candidates, heart allocation policies have evolved to a multitiered algorithm that attempts to prioritize organs to the most infirm, a designation that fluctuates with trends in therapy. The Organ Procurement and Transplantation Network and its committees have been responsive, as demonstrated by recent modifications to pediatric heart allocation and mechanical circulatory support policies and by ongoing efforts to ensure that heart allocation policies are equitable and current. Here we examine the development of US lung and heart allocation policy, evaluate the application of the current policy on clinical practice and explore future directions for lung and heart allocation. PMID:22974276

Colvin-Adams, M; Valapour, M; Hertz, M; Heubner, B; Paulson, K; Dhungel, V; Skeans, M A; Edwards, L; Ghimire, V; Waller, C; Cherikh, W S; Kasiske, B L; Snyder, J J; Israni, A K

2012-12-01

500

The ontogeny of postmaturation resource allocation in turtles.  

PubMed

Resource-allocation decisions vary with life-history strategy, and growing evidence suggests that long-lived endothermic vertebrates direct resources toward growth and self-maintenance when young, increasing allocation toward reproductive effort over time. Few studies have tracked the ontogeny of resource allocation (energy, steroid hormones, etc.) in long-lived ectothermic vertebrates, limiting our understanding of the generality of life-history strategies among vertebrates. We investigated how reproductively mature female painted turtles (Chrysemys picta) from two distinct age classes allocated resources over a 4-yr period and whether resource-allocation patterns varied with nesting experience. We examined age-related variation in body size, egg mass, reproductive frequency, and yolk steroids and report that younger females were smaller and allocated fewer resources to reproduction than did older females. Testosterone levels were higher in eggs from younger females, whereas eggs from second (seasonal) clutches contained higher concentrations of progesterone and estradiol. These allocation patterns resulted in older, larger females laying larger eggs and producing second clutches more frequently than their younger counterparts. We conclude that resource-allocation patterns do vary with age in a long-lived ectotherm. PMID:21460531

Bowden, R M; Paitz, Ryan T; Janzen, Fredric J

2011-01-01