WorldWideScience

Sample records for hard timing constraints

  1. Scheduling of Fault-Tolerant Embedded Systems with Soft and Hard Timing Constraints

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Pop, Paul; Eles, Petru

    2008-01-01

    /utility functions to capture the utility of soft processes. Process re-execution is employed to recover from multiple faults. A single static schedule computed off-line is not fault tolerant and is pessimistic in terms of utility, while a purely online approach, which computes a new schedule every time a process...... fails or completes, incurs an unacceptable overhead. Thus, we use a quasi-static scheduling strategy, where a set of schedules is synthesized off-line and, at run time, the scheduler will select the right schedule based on the occurrence of faults and the actual execution times of processes......In this paper we present an approach to the synthesis of fault-tolerant schedules for embedded applications with soft and hard real-time constraints. We are interested to guarantee the deadlines for the hard processes even in the case of faults, while maximizing the overall utility. We use time...

  2. Evaluating Distributed Timing Constraints

    DEFF Research Database (Denmark)

    Kristensen, C.H.; Drejer, N.

    1994-01-01

    In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....

  3. Running in Hard Times

    Science.gov (United States)

    Berry, John N., III

    2009-01-01

    Roberta Stevens and Kent Oliver are campaigning hard for the presidency of the American Library Association (ALA). Stevens is outreach projects and partnerships officer at the Library of Congress. Oliver is executive director of the Stark County District Library in Canton, Ohio. They have debated, discussed, and posted web sites, Facebook pages,…

  4. Learning With Mixed Hard/Soft Pointwise Constraints.

    Science.gov (United States)

    Gnecco, Giorgio; Gori, Marco; Melacci, Stefano; Sanguineti, Marcello

    2015-09-01

    A learning paradigm is proposed and investigated, in which the classical framework of learning from examples is enhanced by the introduction of hard pointwise constraints, i.e., constraints imposed on a finite set of examples that cannot be violated. Such constraints arise, e.g., when requiring coherent decisions of classifiers acting on different views of the same pattern. The classical examples of supervised learning, which can be violated at the cost of some penalization (quantified by the choice of a suitable loss function) play the role of soft pointwise constraints. Constrained variational calculus is exploited to derive a representer theorem that provides a description of the functional structure of the optimal solution to the proposed learning paradigm. It is shown that such an optimal solution can be represented in terms of a set of support constraints, which generalize the concept of support vectors and open the doors to a novel learning paradigm, called support constraint machines. The general theory is applied to derive the representation of the optimal solution to the problem of learning from hard linear pointwise constraints combined with soft pointwise constraints induced by supervised examples. In some cases, closed-form optimal solutions are obtained.

  5. Task Scheduling on the Cloud with Hard Constraints

    OpenAIRE

    Thai, Long; Varghese, Blesson; Barker, Adam

    2015-01-01

    Scheduling Bag-of-Tasks (BoT) applications on the cloud can be more challenging than grid and cluster environ- ments. This is because a user may have a budgetary constraint or a deadline for executing the BoT application in order to keep the overall execution costs low. The research in this paper is motivated to investigate task scheduling on the cloud, given two hard constraints based on a user-defined budget and a deadline. A heuristic algorithm is proposed and implemented to satisfy the ha...

  6. Density of topological constraints as a metric for predicting glass hardness

    Science.gov (United States)

    Zheng, Qiuju; Yue, Yuanzheng; Mauro, John C.

    2017-07-01

    Topological constraint theory has previously been applied to predict the composition dependence of glass hardness for a variety of different composition families. Some recent findings have cast doubt on the correlation between glass hardness and the number of rigid constraints per atom in silicate glasses. In this letter, we revisit the prediction of hardness for borosilicate and phosphosilicate glasses using four different types of constraint counting approaches: total number of constraints per atom, angular constraints per atom, total constraint density, and angular constraint density. We find that the counting approaches using total constraint density or angular constraint density give an improved prediction of glass hardness. We therefore conclude that glass hardness is governed by the density of rigid constraints under an indenter, rather than by the number of rigid constraints per atom.

  7. Closing in on a Short-Hard Burst Progenitor: Constraints From Early-Time Optical Imaging and Spectroscopy of a Possible Host Galaxy of GRB 050509b

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, Joshua S.; Prochaska, J.X.; Pooley, D.; Blake, C.W.; Foley, R.J.; Jha, S.; Ramirez-Ruiz, E.; Granot, J.; Filippenko, A.V.; Sigurdsson, S.; Barth, A.J.; Chen,; Cooper, M.C.; Falco, E.E.; Gal, R.R.; Gerke, B.F.; Gladders, M.D.; Greene, J.E.; Hennanwi, J.; Ho, L.C.; Hurley, K.; /UC, Berkeley, Astron. Dept. /Lick Observ.

    2005-06-07

    The localization of the short-duration, hard-spectrum gamma-ray burst GRB050509b by the Swift satellite was a watershed event. Never before had a member of this mysterious subclass of classic GRBs been rapidly and precisely positioned in a sky accessible to the bevy of ground-based follow-up facilities. Thanks to the nearly immediate relay of the GRB position by Swift, we began imaging the GRB field 8 minutes after the burst and have continued during the 8 days since. Though the Swift X-ray Telescope (XRT) discovered an X-ray afterglow of GRB050509b, the first ever of a short-hard burst, thus far no convincing optical/infrared candidate afterglow or supernova has been found for the object. We present a re-analysis of the XRT afterglow and find an absolute position of R.A. = 12h36m13.59s, Decl. = +28{sup o}59'04.9'' (J2000), with a 1{sigma} uncertainty of 3.68'' in R.A., 3.52'' in Decl.; this is about 4'' to the west of the XRT position reported previously. Close to this position is a bright elliptical galaxy with redshift z = 0.2248 {+-} 0.0002, about 1' from the center of a rich cluster of galaxies. This cluster has detectable diffuse emission, with a temperature of kT = 5.25{sub -1.68}{sup +3.36} keV. We also find several ({approx}11) much fainter galaxies consistent with the XRT position from deep Keck imaging and have obtained Gemini spectra of several of these sources. Nevertheless we argue, based on positional coincidences, that the GRB and the bright elliptical are likely to be physically related. We thus have discovered reasonable evidence that at least some short-duration, hard-spectra GRBs are at cosmological distances. We also explore the connection of the properties of the burst and the afterglow, finding that GRB050509b was underluminous in both of these relative to long-duration GRBs. However, we also demonstrate that the ratio of the blast-wave energy to the {gamma}-ray energy is consistent with that

  8. Cosmological Constraints from Gravitational Lens Time Delays

    Science.gov (United States)

    Coe, Dan; Moustakas, Leonidas A.

    2009-11-01

    Future large ensembles of time delay (TD) lenses have the potential to provide interesting cosmological constraints complementary to those of other methods. In a flat universe with constant w including a Planck prior, The Large Synoptic Survey Telescope TD measurements for ~4000 lenses should constrain the local Hubble constant h to ~0.007 (~1%), Ω de to ~0.005, and w to ~0.026 (all 1σ precisions). Similar constraints could be obtained by a dedicated gravitational lens observatory (OMEGA) which would obtain precise TD and mass model measurements for ~100 well-studied lenses. We compare these constraints (as well as those for a more general cosmology) to the "optimistic Stage IV" constraints expected from weak lensing, supernovae, baryon acoustic oscillations, and cluster counts, as calculated by the Dark Energy Task Force. TDs yield a modest constraint on a time-varying w(z), with the best constraint on w(z) at the "pivot redshift" of z ≈ 0.31. Our Fisher matrix calculation is provided to allow TD constraints to be easily compared to and combined with constraints from other experiments. We also show how cosmological constraining power varies as a function of numbers of lenses, lens model uncertainty, TD precision, redshift precision, and the ratio of four-image to two-image lenses.

  9. Time Optimal Run-time Evaluation of Distributed Timing Constraints in Process Control Software

    DEFF Research Database (Denmark)

    Drejer, N.; Kristensen, C.H.

    1993-01-01

    This paper considers run-time evaluation of an important class of constraints; Timing constraints. These appear extensively in process control systems. Timing constraints are considered in distributed systems, i.e. systems consisting of multiple autonomous nodes.........This paper considers run-time evaluation of an important class of constraints; Timing constraints. These appear extensively in process control systems. Timing constraints are considered in distributed systems, i.e. systems consisting of multiple autonomous nodes......

  10. Service-Oriented Architecture (SOA) Instantiation within a Hard Real-Time, Deterministic Combat System Environment

    Science.gov (United States)

    Moreland, James D., Jr

    2013-01-01

    This research investigates the instantiation of a Service-Oriented Architecture (SOA) within a hard real-time (stringent time constraints), deterministic (maximum predictability) combat system (CS) environment. There are numerous stakeholders across the U.S. Department of the Navy who are affected by this development, and therefore the system…

  11. Towards harnessing theories through tool support for hard real-time Java programming

    DEFF Research Database (Denmark)

    Bøgholm, Thomas; Frost, Christian; Hansen, Rene Rydhof

    2013-01-01

    We present a rationale for a selection of tools that assist developers of hard real-time applications to verify that programs conform to a Java real-time profile and that platform-specific resource constraints are satisfied. These tools are specialised instances of more generic static analysis an...

  12. Towards harnessing theories through tool support for hard real-time Java programming

    DEFF Research Database (Denmark)

    Søndergaard, Hans; Bøgholm, Thomas; Frost, Christian

    2012-01-01

    We present a rationale for a selection of tools that assist developers of hard real-time applications to verify that programs conform to a Java real-time profile and that platform-specific resource constraints are satisfied. These tools are specialised instances of more generic static analysis an...

  13. Notes on Timed Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia, Frank D.

    2004-01-01

    and program reactive systems. This note provides a comprehensive introduction to the background for and central notions from the theory of tccp. Furthermore, it surveys recent results on a particular tccp calculus, ntcc, and it provides a classification of the expressive power of various tccp languages.......A constraint is a piece of (partial) information on the values of the variables of a system. Concurrent constraint programming (ccp) is a model of concurrency in which agents (also called processes) interact by telling and asking information (constraints) to and from a shared store (a constraint...

  14. From Hard Times to Better Times: College Majors, Unemployment, and Earnings

    Science.gov (United States)

    Carnevale, Anthony P.; Cheah, Ban

    2015-01-01

    This third installment of "Hard Times" updates the previous analyses of college majors, unemployment, and earnings over the Great Recession. While there is wide variation by college majors, hard times have become better times for most college graduates, but the recovery is far from complete. Hard times are becoming better times for most…

  15. Hard Real-Time Networking on FIrewire

    NARCIS (Netherlands)

    Zhang, Yuchen; Orlic, B.; Visser, P.M.; Broenink, Johannes F.; Marquet, P; McGuire, N; Wurmsdobler, P

    2005-01-01

    This paper investigates the possibility of using standard, low-cost, widely used FireWire as a new generation fieldbus medium for real-time distributed control applications. A real-time software subsys- tem, RT-FireWire was designed that can, in combination with Linux-based real-time operating

  16. IMPORT PRICES AND HARD CURRENCY CONSTRAINTS IN EASTERN EUROPE: IMPLICATIONS FOR COARSE GRAIN IMPORTS AND PRODUCTION OF MEAT

    OpenAIRE

    Garcia, Roberto J.; Miljkovic, Dragan; Gomez, Miguel I.

    1998-01-01

    The objectives of this study were (a) to determine the degree to which hard currency earnings constrained overall imports and coarse grain imports in command economies; (b) to measure the importance of import prices on grain imports and to trace the link of grain availability to meat production; and (c) to determine how economic and political reforms in the selected countries may have affected the hard currency constraint, the importance of import prices, and grain imports and meat production...

  17. Constraint Logic Programming for Resolution of Relative Time Expressions

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2014-01-01

    Translating time expression into absolute time points or durations is a challenge for natural languages processing such as text mining and text understanding in general. We present a constraint logic language CLP(Time) tailored to text usages concerned with time and calendar. It provides a simple...... and flexible formalism to express relationships between different time expressions in a text, thereby giving a recipe for resolving them into absolute time. A constraint solver is developed which, as opposed to some earlier approaches, is independent of the order in which temporal information is introduced...

  18. Evolutionary stability for matrix games under time constraints.

    Science.gov (United States)

    Garay, József; Csiszár, Villő; Móri, Tamás F

    2017-02-21

    Game theory focuses on payoffs and typically ignores time constraints that play an important role in evolutionary processes where the repetition of games can depend on the strategies, too. We introduce a matrix game under time constraints, where each pairwise interaction has two consequences: both players receive a payoff and they cannot play the next game for a specified time duration. Thus our model is defined by two matrices: a payoff matrix and an average time duration matrix. Maynard Smith's concept of evolutionary stability is extended to this class of games. We illustrate the effect of time constraints by the well-known prisoner's dilemma game, where additional time constraints can ensure the existence of unique evolutionary stable strategies (ESS), both pure and mixed, or the coexistence of two pure ESS. Our general results may be useful in several fields of biology where evolutionary game theory is applied, principally in ecological games, where time constraints play an inevitable role. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Synthesis of Flexible Fault-Tolerant Schedules with Preemption for Mixed Soft and Hard Real-Time Systems

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Pop, Paul; Eles, Petru

    2008-01-01

    In this paper we present an approach for scheduling with preemption for fault-tolerant embedded systems composed of soft and hard real-time processes. We are interested to maximize the overall utility for average, most likely to happen, scenarios and to guarantee the deadlines for the hard...... as a method to generate flexible schedules that maximize the overall utility for the average case while guarantee timing constraints in the worst case. Our scheduling algorithms determine off-line when to preempt and when to resurrect processes. The experimental results show the superiority of our new...

  20. Evidence-based history taking under "time constraint"

    OpenAIRE

    Alireza Moayyeri; Akbar Soltani; Hamideh Moosapour; Mohsin Raza

    2011-01-01

    Physicians all through the world visit patients under time limitations. The most important troubled clinical skill under ?time constraint? is the diagnostic approach. In this situation, clinicians need some diagnostic approaches to reduce both diagnostic time and errors. It seems that highly experienced physicians utilize some special tactics in this regard. Evidence-based medicine (EBM) as a relatively new paradigm for clinical practice stresses on using research evidences in diagnostic eval...

  1. Infinite Runs in Weighted Timed Automata with Energy Constraints

    DEFF Research Database (Denmark)

    Bouyer, Patricia; Fahrenberg, Uli; Larsen, Kim Guldstrand

    2008-01-01

    We study the problems of existence and construction of infinite schedules for finite weighted automata and one-clock weighted timed automata, subject to boundary constraints on the accumulated weight. More specifically, we consider automata equipped with positive and negative weights on transitions...

  2. Automatic Verification of Timing Constraints for Safety Critical Space Systems

    Science.gov (United States)

    Fernandez, Javier; Parra, Pablo; Sanchez Prieto, Sebastian; Polo, Oscar; Bernat, Guillem

    2015-09-01

    In this paper is presented an automatic process of verification. We focus in the verification of scheduling analysis parameter. This proposal is part of process based on Model Driven Engineering to automate a Verification and Validation process of the software on board of satellites. This process is implemented in a software control unit of the energy particle detector which is payload of Solar Orbiter mission. From the design model is generated a scheduling analysis model and its verification model. The verification as defined as constraints in way of Finite Timed Automatas. When the system is deployed on target the verification evidence is extracted as instrumented points. The constraints are fed with the evidence, if any of the constraints is not satisfied for the on target evidence the scheduling analysis is not valid.

  3. Thinking aloud in the presence of interruptions and time constraints

    DEFF Research Database (Denmark)

    Hertzum, Morten; Holmegaard, Kristin Due

    2013-01-01

    Thinking aloud is widely used for usability evaluation and its reactivity is therefore important to the quality of evaluation results. This study investigates whether thinking aloud (i.e., verbalization at levels 1 and 2) affects the behaviour of users who perform tasks that involve interruptions...... and time constraints, two frequent elements of real-world activities. We find that the presence of auditory, visual, audiovisual, or no interruptions interacts with thinking aloud for task solution rate, task completion time, and participants’ fixation rate. Thinking-aloud participants also spend longer...... responding to interruptions than control participants. Conversely, the absence or presence of time constraints does not interact with thinking aloud, suggesting that time pressure is less likely to make thinking aloud reactive than previously assumed. Our results inform practitioners faced with the decision...

  4. Using LDPC Code Constraints to Aid Recovery of Symbol Timing

    Science.gov (United States)

    Jones, Christopher; Villasnor, John; Lee, Dong-U; Vales, Esteban

    2008-01-01

    A method of utilizing information available in the constraints imposed by a low-density parity-check (LDPC) code has been proposed as a means of aiding the recovery of symbol timing in the reception of a binary-phase-shift-keying (BPSK) signal representing such a code in the presence of noise, timing error, and/or Doppler shift between the transmitter and the receiver. This method and the receiver architecture in which it would be implemented belong to a class of timing-recovery methods and corresponding receiver architectures characterized as pilotless in that they do not require transmission and reception of pilot signals. Acquisition and tracking of a signal of the type described above have traditionally been performed upstream of, and independently of, decoding and have typically involved utilization of a phase-locked loop (PLL). However, the LDPC decoding process, which is iterative, provides information that can be fed back to the timing-recovery receiver circuits to improve performance significantly over that attainable in the absence of such feedback. Prior methods of coupling LDPC decoding with timing recovery had focused on the use of output code words produced as the iterations progress. In contrast, in the present method, one exploits the information available from the metrics computed for the constraint nodes of an LDPC code during the decoding process. In addition, the method involves the use of a waveform model that captures, better than do the waveform models of the prior methods, distortions introduced by receiver timing errors and transmitter/ receiver motions. An LDPC code is commonly represented by use of a bipartite graph containing two sets of nodes. In the graph corresponding to an (n,k) code, the n variable nodes correspond to the code word symbols and the n-k constraint nodes represent the constraints that the code places on the variable nodes in order for them to form a valid code word. The decoding procedure involves iterative computation

  5. Hard emission at late times from SN 1987A

    Science.gov (United States)

    Woosley, S. E.; Hartmann, Dieter; Pinto, Philip A.

    1989-01-01

    A model for the explosion that has been successful in predicting and explaining the evolution of SN 1987A during its first one and one-half years is used to calculate the future photometric evolution of the supernova in the UV-optical-IR, X-ray, and gamma-ray bands using Monte Carlo techniques. Special attention is given to the contribution from radioactive isotopes other than Co-56, notably Co-57, Ti-44, and Na-22, and to the possible appearance, probably within the next year, of X-rays from an accreting magnetic neutron star at the center of the supernova. The signature of a radio pulsar like the Crab is also considered. In both cases the time history of the bolometric light curve may be a more sensitive diagnostic than the existence of either pulses or hard emission, but will become confused in the near future by contributions from the rare radioactivities. A source as faint as the pulsed emission of the Crab pulsar will never be discernable in the bolometric light curve. Pulsed hard emission is best sought near 30 keV near the end of 1989 (and thereafter), although more sensitive instrumentation than hitherto employed may be necessary.

  6. Time-fixed rendezvous by impulse factoring with an intermediate timing constraint. [for transfer orbits

    Science.gov (United States)

    Green, R. N.; Kibler, J. F.; Young, G. R.

    1974-01-01

    A method is presented for factoring a two-impulse orbital transfer into a three- or four-impulse transfer which solves the rendezvous problem and satisfies an intermediate timing constraint. Both the time of rendezvous and the intermediate time of a alinement are formulated as any element of a finite sequence of times. These times are integer multiples of a constant plus an additive constant. The rendezvous condition is an equality constraint, whereas the intermediate alinement is an inequality constraint. The two timing constraints are satisfied by factoring the impulses into collinear parts that vectorially sum to the original impulse and by varying the resultant period differences and the number of revolutions in each orbit. Five different types of solutions arise by considering factoring either or both of the two impulses into two or three parts with a limit for four total impulses. The impulse-factoring technique may be applied to any two-impulse transfer which has distinct orbital periods.

  7. Hard-Boiled for Hard Times in Leonardo Padura Fuentes's Detective Fiction

    Science.gov (United States)

    Song, H. Rosi

    2009-01-01

    Focusing on Leonardo Padura Fuentes's hard-boiled fiction, this essay traces the origin and evolution of the genre in Cuba. Padura Fuentes has challenged the officially sanctioned socialist "literatura policial" that became popular in the 1970s and 1980s. creating a new model of criticism that is not afraid to confront the island's socio-economic…

  8. LEISURE TIME - PHYSICAL ACTIVITY CONSTRAINTS AT HIGH SCHOOLS

    Directory of Open Access Journals (Sweden)

    Hüseyin GÜMÜŞ

    2014-07-01

    Full Text Available The aim of the study was to investigate the constraints that prevented the young people who studied at high schools from participating in leisure time physical activities. The population of the study was composed of the students who studied at high schools in Afyonkarahisar Province. Method of population selection and sample recruitment was purposive sampling. 783 volunteers participated in the study. It was seen that some of the answers were invalid and therefore, sample was made up by 750 participants [14 - 18 age (x=15.77, sd=1.05, 64.9% (487 of them female students]. As the data collection tool; Leisure Time - Physical Activity Constraints (LTPA - C developed by Öcal (2012 was used. The scale is composed of 8 subscales: body perception, facilities, income, family, skill perception, time, willpower and society. It is a 6 - point Likert type scale and measures participants‟ physical activity participation status in their leisure times. For the analyses of the data; descriptive statistics, univariate analysis of variance (ANOVA and Independent Samples T - Test were used. According to the study findings; it was found out that there were significant differences among the participants in terms of the scores of LTPA - C as far as participants‟ genders, parental educatio nal status, maternal professional status, school types and grades (p<0.05.

  9. Trajectory reshaping based guidance with impact time and angle constraints

    Directory of Open Access Journals (Sweden)

    Zhao Yao

    2016-08-01

    Full Text Available This study presents a novel impact time and angle constrained guidance law for homing missiles. The guidance law is first developed with the prior-assumption of a stationary target, which is followed by the practical extension to a maneuvering target scenario. To derive the closed-form guidance law, the trajectory reshaping technique is utilized and it results in defining a specific polynomial function with two unknown coefficients. These coefficients are determined to satisfy the impact time and angle constraints as well as the zero miss distance. Furthermore, the proposed guidance law has three additional guidance gains as design parameters which make it possible to adjust the guided trajectory according to the operational conditions and missile’s capability. Numerical simulations are presented to validate the effectiveness of the proposed guidance law.

  10. Comparison of time-dependent changes in the surface hardness of different composite resins

    Science.gov (United States)

    Ozcan, Suat; Yikilgan, Ihsan; Uctasli, Mine Betul; Bala, Oya; Kurklu, Zeliha Gonca Bek

    2013-01-01

    Objective: The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). Materials and Methods: From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bottom surface hardness of these samples was measured using a Vicker's hardness tester. The samples were then stored at 37°C and 100% humidity. After 24 h and 7, 30 and 90 days, the top and bottom surface hardness of the samples was measured. In each measurement, the rate between the hardness of the top and bottom surfaces were recorded as the hardness rate. Statistical analysis was performed by one-way analysis of variance, multiple comparisons by Tukey's test and binary comparisons by t-test with a significance level of P = 0.05. Results: The highest hardness values were obtained from each two surfaces of Majesty Posterior and the lowest from Filtek Silorane. Both the top and bottom surface hardness of the methacrylate based composite resins was high and there was a statistically significant difference between the top and bottom hardness values of only the silorane-based composite, Filtek Silorane (P hardness values of all test groups increased after 24 h (P hardness ratio, the use of incremental technic during application is more important than methacrylate based composites. PMID:24966724

  11. Timing of Family Income, Borrowing Constraints and Child Achievement

    DEFF Research Database (Denmark)

    Humlum, Maria Knoth

    In this paper, I investigate the effects of the timing of family income on child achievement production. Detailed administrative data augmented with PISA test scores at age 15 are used to analyze the effects of the timing of family income on child achievement. Contrary to many earlier studies, te...... with generous child and education subsidies. Actually, later family income (age 12-15) is a more important determinant of child achievement than earlier income.......In this paper, I investigate the effects of the timing of family income on child achievement production. Detailed administrative data augmented with PISA test scores at age 15 are used to analyze the effects of the timing of family income on child achievement. Contrary to many earlier studies......, tests for early borrowing constraints suggest that parents are not constrained in early investments in their children's achievement, and thus that the timing of income does not matter for long-term child outcomes. This is a reasonable result given the setting in a Scandinavian welfare state...

  12. Asymmetric continuous-time neural networks without local traps for solving constraint satisfaction problems.

    Directory of Open Access Journals (Sweden)

    Botond Molnár

    Full Text Available There has been a long history of using neural networks for combinatorial optimization and constraint satisfaction problems. Symmetric Hopfield networks and similar approaches use steepest descent dynamics, and they always converge to the closest local minimum of the energy landscape. For finding global minima additional parameter-sensitive techniques are used, such as classical simulated annealing or the so-called chaotic simulated annealing, which induces chaotic dynamics by addition of extra terms to the energy landscape. Here we show that asymmetric continuous-time neural networks can solve constraint satisfaction problems without getting trapped in non-solution attractors. We concentrate on a model solving Boolean satisfiability (k-SAT, which is a quintessential NP-complete problem. There is a one-to-one correspondence between the stable fixed points of the neural network and the k-SAT solutions and we present numerical evidence that limit cycles may also be avoided by appropriately choosing the parameters of the model. This optimal parameter region is fairly independent of the size and hardness of instances, this way parameters can be chosen independently of the properties of problems and no tuning is required during the dynamical process. The model is similar to cellular neural networks already used in CNN computers. On an analog device solving a SAT problem would take a single operation: the connection weights are determined by the k-SAT instance and starting from any initial condition the system searches until finding a solution. In this new approach transient chaotic behavior appears as a natural consequence of optimization hardness and not as an externally induced effect.

  13. Study of orbital transfers with time constraint and fuel optimization

    Science.gov (United States)

    Meireles, L. G.; Rocco, E. M.

    2017-10-01

    Over the decades, with the advance in computational power and the development of new optimization techniques, a new opportunity arose for a reviewed approach and analysis of already existing solutions to orbital transfer problems. With that in mind, a study was proposed over Lambert’s problem of bi-impulsive orbital transfers with time constraint for the execution of minimum fuel maneuvers between coplanar and non coplanar elliptical orbits. In order to achieve this goal, a genetic search algorithm was developed to determine the minimum fuel trajectory with an iterative variation of two Keplerian elements of the final orbit, one of them being the mean anomaly and the other a choice between the eccentricity, the inclination or the argument of periapsis. A number of six simulations were performed under these conditions, using different values - on each simulation - for the Keplerian elements of the final orbits not being iteratively varied. Remarkable sections were noted regarding the behaviour of fuel consumption values of the minimum fuel trajectories. One of which was a noted relation between the lowest cost minimum fuel transfers and the ratio of the semi-major axis and eccentricity of these transfers’ initial and final orbits, considering both the orbits have the same value of argument of periapsis. Amongst all simulations, it was important to identify the choice between short or long way for the determination of the minimum fuel transfer, analysing the implications of that choice on the transfer time.

  14. Minimizing total weighted tardiness for the single machine scheduling problem with dependent setup time and precedence constraints

    Directory of Open Access Journals (Sweden)

    Hamidreza Haddad

    2012-04-01

    Full Text Available This paper tackles the single machine scheduling problem with dependent setup time and precedence constraints. The primary objective of this paper is minimization of total weighted tardiness. Since the complexity of the resulted problem is NP-hard we use metaheuristics method to solve the resulted model. The proposed model of this paper uses genetic algorithm to solve the problem in reasonable amount of time. Because of high sensitivity of GA to its initial values of parameters, a Taguchi approach is presented to calibrate its parameters. Computational experiments validate the effectiveness and capability of proposed method.

  15. Time-dependent behaviour of deep level tabular excavations in hard rock

    CSIR Research Space (South Africa)

    Malan, DF

    1999-04-01

    Full Text Available Although hard rock is not usually associated with large creep deformation, significant time-dependent behaviour is observed in the tabular excavations of the South African gold mines. Time-dependent closure data was collected in stopes...

  16. Control Loop Processor (CLP)-Platform for Hard Real-Time Space Applications

    Science.gov (United States)

    Ruiz, Marco; Fern, Jean-Brieuc; de la vallee Poussin, Henri

    2016-08-01

    Nowadays, the field of tight control loops, characterized by hard real-time constraints (loop frequency > 1 kHz) in conjunction with complex algorithmic needs, currently lacks a microprocessor allowing to make a software programmable approach economically and technically viable. The control of electro-mechanical actuators is an example of target application.A dedicated space-hardened microprocessor, called Control Loop Processor (CLP), is currently under development - with the tight collaboration of ESA TEC/ED - and integrates several key features ensuring a fully deterministic behaviour as well as an embedded robustness/anomaly management in conjunction with vectorial IEEE-754 floating-points operations.A wide range of interfaces has also been selected to cover current and future space-oriented communication interfaces. A software development environment, integrating a C compiler and a code generator taking Simulink files as code source, is currently being developed on the LLVM framework. The assembler and disassembler, based on the LLVM engine, are currently available and have been used for the processor validation and for a motor control demonstration.

  17. Effect of water hardness on cardiovascular mortality: an ecological time series approach.

    Science.gov (United States)

    Lake, I R; Swift, L; Catling, L A; Abubakar, I; Sabel, C E; Hunter, P R

    2010-12-01

    Numerous studies have suggested an inverse relationship between drinking water hardness and cardiovascular disease. However, the weight of evidence is insufficient for the WHO to implement a health-based guideline for water hardness. This study followed WHO recommendations to assess the feasibility of using ecological time series data from areas exposed to step changes in water hardness to investigate this issue. Monthly time series of cardiovascular mortality data, subdivided by age and sex, were systematically collected from areas reported to have undergone step changes in water hardness, calcium and magnesium in England and Wales between 1981 and 2005. Time series methods were used to investigate the effect of water hardness changes on mortality. No evidence was found of an association between step changes in drinking water hardness or drinking water calcium and cardiovascular mortality. The lack of areas with large populations and a reasonable change in magnesium levels precludes a definitive conclusion about the impact of this cation. We use our results on the variability of the series to consider the data requirements (size of population, time of water hardness change) for such a study to have sufficient power. Only data from areas with large populations (>500,000) are likely to be able to detect a change of the size suggested by previous studies (rate ratio of 1.06). Ecological time series studies of populations exposed to changes in drinking water hardness may not be able to provide conclusive evidence on the links between water hardness and cardiovascular mortality unless very large populations are studied. Investigations of individuals may be more informative.

  18. Chasing the College Dream in Hard Economic Times. Issue Brief

    Science.gov (United States)

    Buddin, Richard; Croft, Michelle

    2014-01-01

    Slow economic growth in the past several years has strained the financial resources of many American families and heightened financial burdens for families hoping to support their children's college education. These economic struggles come at a critical time for high school students who rely on family resources to fund large portions of college…

  19. Calibration of a time-resolved hard-x-ray detector using radioactive sources

    Energy Technology Data Exchange (ETDEWEB)

    Stoeckl, C., E-mail: csto@lle.rochester.edu; Theobald, W.; Regan, S. P.; Romanofsky, M. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

    2016-11-15

    A four-channel, time-resolved, hard x-ray detector (HXRD) has been operating at the Laboratory for Laser Energetics for more than a decade. The slope temperature of the hot-electron population in direct-drive inertial confinement fusion experiments is inferred by recording the hard x-ray radiation generated in the interaction of the electrons with the target. Measuring the energy deposited by hot electrons requires an absolute calibration of the hard x-ray detector. A novel method to obtain an absolute calibration of the HXRD using single photons from radioactive sources was developed, which uses a thermoelectrically cooled, low-noise, charge-sensitive amplifier.

  20. Effects of Social Constraints on Career Maturity: The Mediating Effect of the Time Perspective

    Science.gov (United States)

    Kim, Kyung-Nyun; Oh, Se-Hee

    2013-01-01

    Previous studies have provided mixed results for the effects of social constraints on career maturity. However, there has been growing interest in these effects from the time perspective. Few studies have examined the effects of social constraints on the time perspective which in turn influences career maturity. This study examines the mediating…

  1. New Constraints on the Hard Ionizing Photon Budget and the Lifetime and Obscuration of Quasars During the Epoch of Helium Reionization

    Science.gov (United States)

    Davies, Frederick

    2017-08-01

    The epoch of helium reionization was a major milestone in the history of the Universe, a direct consequence of supermassive black hole growth and the cumulative output of hard ionizing photons by quasars. Our observations of the He II Ly-alpha forest with HST/COS in 26 quasar sightlines show strong fluctuations at z 3, consistent with our state-of-the-art simulations of the He II reionization epoch. However, our detection of transmission at z > 3.5 is inconsistent with all He II reionization models. Resolving this puzzle requires an extensive parameter study of He II reionization, which we propose to carry out using our fast, efficient simulations. The He II Ly-alpha forest is also sensitive to the effect of quasar radiation illuminating the intergalactic medium, known as the proximity effect. We have performed an ambitious ground-based imaging and spectroscopic survey for z 3 quasars in the foreground of HeII sightlines observed with HST/COS, and statistically detected the transverse proximity effect for the first time. The strength of this effect depends on both the quasar lifetime and the opening angle of quasar emission (or the fraction of obscured quasars), and we propose to use our He II reionization simulations to interpret this new measurement. Finally, the line-of-sight proximity effect due to the background quasar provides an independent constraint on the quasar lifetime. Our preliminary comparison of He II spectra to our radiative transfer simulations suggests a quasar lifetime > 10 Myr. We propose to use our He II reionization simulations to model this diverse set of observations and fully capitalize on the far-UV legacy of HST.

  2. Reconfiguration in FPGA-Based Multi-Core Platforms for Hard Real-Time Applications

    DEFF Research Database (Denmark)

    Pezzarossa, Luca; Schoeberl, Martin; Sparsø, Jens

    2016-01-01

    In general-purpose computing multi-core platforms, hardware accelerators and reconfiguration are means to improve performance; i.e., the average-case execution time of a software application. In hard real-time systems, such average-case speed-up is not in itself relevant - it is the worst-case ex...... partial reconfiguration capabilities found in modern FPGAs....

  3. Constraining designs for synthesis and timing analysis a practical guide to synopsys design constraints (SDC)

    CERN Document Server

    Gangadharan, Sridhar

    2013-01-01

    This book serves as a hands-on guide to timing constraints in integrated circuit design.  Readers will learn to maximize performance of their IC designs, by specifying timing requirements correctly.  Coverage includes key aspects of the design flow impacted by timing constraints, including synthesis, static timing analysis and placement and routing.  Concepts needed for specifying timing requirements are explained in detail and then applied to specific stages in the design flow, all within the context of Synopsys Design Constraints (SDC), the industry-leading format for specifying constraints.  ·         Provides a hands-on guide to synthesis and timing analysis, using Synopsys Design Constraints (SDC), the industry-leading format for specifying constraints; ·         Includes key topics of interest to a synthesis, static timing analysis or  place and route engineer; ·         Explains which constraints command to use for ease of maintenance and reuse, given several options pos...

  4. General-Weighted Least-Norm Control for Redundant Manipulators under Time-Dependent Constraint

    Directory of Open Access Journals (Sweden)

    Pei Jiang

    2015-05-01

    Full Text Available Previous research dealing with constrained kinematic redundancy problems focuses on manipulators with time-independent constraints. This paper extends the general-weighted least-norm (GWLN method to manipulators with time-dependent constraints by introducing time-dependent virtual joints. In the virtual joint space, corresponding task space velocity is revised to encapsulate the effects of time-dependent parameters of constraints. This is done so that an intermediate kinematic control problem with only joint limit is obtained. Then, the inverse kinematic problem is solved in the virtual joint space. A new inverse-weighted matrix setting criterion is proposed to replace the one-step prediction that originally complicated implementation of the GWLN method. To demonstrate the efficacy of the method, simulations and experiments are carried out on a five-link welding manipulator to track the welding trajectory. Time-dependent orientation constraint and preventing joint limits is guaranteed using this method.

  5. RealWorld evaluation: working under budget, time, data, and political constraints

    National Research Council Canada - National Science Library

    Bamberger, Michael; Rugh, Jim; Mabry, Linda

    2012-01-01

    This book addresses the challenges of conducting program evaluations in real-world contexts where evaluators and their clients face budget and time constraints and where critical data may be missing...

  6. Physical education and leisure time preferences of pupils who are deaf or hard of hearing

    Directory of Open Access Journals (Sweden)

    Petra Kurková

    2010-01-01

    Full Text Available Education in the Czech Republic in accordance with the current legislation enables the children, pupils and students with disabilities to have equal access to education, where content, forms and methods meet the educational requirements of those individuals. From the point of view of the health aspect in their adulthood, especially the educational fields of health and physical education are crucial for pupils. The purpose of this study was to compare the dimensions of emotional reactions of pupils who are deaf or hard of hearing in schools for the deaf and those compare with integrated pupils who are deaf or hard of hearing at basic school (grades 6th-9th enrolled in physical education classes. It was also compared preferences in leisure time activities and the knowledge of pupils who are deaf or hard of hearing in both schools settings with regard to sport and sports activities related to this community. Participants in this study were integrated pupils who are deaf or hard of hearing (n = 7, whose average age was 14.43 ± 1.27 years. These pupils were compared with pupils from schools for the deaf (n = 32; age 15.19 ± 1.24 years. At school for the deaf who was evaluated separately, were included 27 pupils who are deaf or hard of hearing (n = 27, age 15.41 ± 1.28 years. The standardized questionnaire DEMOR (dimensions of emotional reactions was used in data collection. This questionnaire was adapted with regards to conditions of pupils who are deaf or hard of hearing. In presented study positive relationships to physical education in pupils who are deaf or hard of hearing were found. Only at schools for the deaf (not counting school for the deaf, which was evaluated separately strongly lower negative relationships than in pupils from general schools were found. Those negative attitudes of pupils to physical education could be related to the followings: lower physically fitness and the impact of teachers (these variables were not tested in

  7. Social Justice in Hard Times: Celebrating the Vision of Dr. Martin Luther King, Jr.

    Science.gov (United States)

    Nieto, Sonia

    2005-01-01

    It is important to remember that one's presence "can" create a clamor, a person's action "does" make a difference. The author is reminded of this fact whenever he thinks about a poem by Angel Nieto. Similarly, individuals need to be reminded of this fact more than ever before because these are hard times for social justice. As individuals…

  8. Reprint 2007: Why Academics Have a Hard Time Writing Good Grants Proposals

    Science.gov (United States)

    Porter, Robert

    2017-01-01

    This paper discusses the contrasting perspectives of academic prose versus grant writing, and lists strategies grant specialists can use to help researchers break old habits and replace them with techniques better suited to the world of competitive grant proposals. [This article is a reprint of "Why Academics Have a Hard Time Writing Good…

  9. Simulating the time-dependent behaviour of excavations in hard rock

    CSIR Research Space (South Africa)

    Malan, DF

    2002-10-01

    Full Text Available Although hard rock is not usually associated with large creep deformation, data collected from the tunnels and stopes of the deep South African gold mines illustrates significant time-dependent behaviour. Apart from application in mining, a better...

  10. Hardness improvement on low carbon steel using pack carbonitriding method with holding time variation

    Directory of Open Access Journals (Sweden)

    Puspitasari Poppy

    2017-01-01

    Full Text Available Carbonitriding is a surface hardening process of steel by heating on critical temperature, quench and followed by tempering process. In this research, pack media in carbonitriding was used as a new method. Usually, this process has been obtained using gas and liquid carbonitriding methods. The specimen used in this research is low carbon steel (St. 41 consist of 0.1517% carbon, 0.1994% of silicon, 0.5631% of manganese, 0.0224% of phosphorus, and 0.047% of sulfur. Temperature for pack carbonitriding was at 700 °C, 750 °C and 800 °C and holding time variation 60 minutes and 120 minutes respectively. The result showed that carbonitriding temperature difference affect the mechanical properties of steel St. 41. Steel hardness was increased at lower holding time (60 minutes compared to 120 minutes. The result showed that at 700 °C and 750 °C with 60 minutes variation, the steel hardness increase from 85.7 HRB to 95.7 HRB and at 800 °C the hardness decrease to 93.1 HRB. Meanwhile, at holding time of 120 minutes, steel hardness decrease from 94.1 HRB to 92.7 HRB. This result caused by austenite phase produced at longer period of holding time.

  11. Time for Each Other: Work and Family Constraints Among Couples.

    Science.gov (United States)

    Flood, Sarah M; Genadek, Katie R

    2016-02-01

    Little is known about couples' shared time and how actual time spent together is associated with well-being. In this study, the authors investigated how work and family demands are related to couples' shared time (total and exclusive) and individual well-being (happiness, meaningfulness, and stress) when with one's spouse. They used individual-level data from the 2003-2010 American Time Use Survey (N = 46,883), including the 2010 Well-Being Module. The results indicated that individuals in full-time working dual-earner couples spend similar amounts of time together as individuals in traditional breadwinner-homemaker arrangements on weekdays after accounting for daily work demands. The findings also show that parents share significantly less total and exclusive spousal time together than nonparents, though there is considerable variation among parents by age of the youngest child. Of significance is that individuals experience greater happiness and meaning and less stress during time spent with a spouse opposed to time spent apart.

  12. Experimental Constraints of the Exotic Shearing of Space-Time

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Jonathan William [Univ. of Chicago, IL (United States)

    2016-08-01

    The Holometer program is a search for rst experimental evidence that space-time has quantum structure. The detector consists of a pair of co-located 40-m power-recycled interferometers whose outputs are read out synchronously at 50 MHz, achieving sensitivity to spatiallycorrelated uctuations in dierential position on time scales shorter than the light-crossing time of the instruments. Unlike gravitational wave interferometers, which time-resolve transient geometrical disturbances in the spatial background, the Holometer is searching for a universal, stationary quantization noise of the background itself. This dissertation presents the nal results of the Holometer Phase I search, an experiment congured for sensitivity to exotic coherent shearing uctuations of space-time. Measurements of high-frequency cross-spectra of the interferometer signals obtain sensitivity to spatially-correlated eects far exceeding any previous measurement, in a broad frequency band extending to 7.6 MHz, twice the inverse light-crossing time of the apparatus. This measurement is the statistical aggregation of 2.1 petabytes of 2-byte dierential position measurements obtained over a month-long exposure time. At 3 signicance, it places an upper limit on the coherence scale of spatial shear two orders of magnitude below the Planck length. The result demonstrates the viability of this novel spatially-correlated interferometric detection technique to reach unprecedented sensitivity to coherent deviations of space-time from classicality, opening the door for direct experimental tests of theories of relational quantum gravity.

  13. Departure time choice: Modelling individual preferences, intention and constraints

    DEFF Research Database (Denmark)

    Thorhauge, Mikkel

    departure time. Parallel with the micro-economic theory, the psychology literature has evidenced that individuals’ behaviours are driven by underlying latent constructs, such as attitude, norms and perceptions. In the past decades, more attention has been given to incorporate and understand underlying......’ attitudes, norms and perception towards being on time (or towards reducing travel and cost) other than by objective measure of times and costs. Arellana et al. (2012) are the only ones who consider these effects in the context of departure time, though they focus only on attitudes. This thesis approaches...... by nearly all studies within departure time. More importantly it shows that the underlying psychological processes are more complex than simply accounting for attitudes and perceptions which are typically used in other areas. The work in this PhD thesis accounts for the full Theory of Planned Behaviour...

  14. Timing of Family Income, Borrowing Constraints, and Child Achievement

    DEFF Research Database (Denmark)

    Humlum, Maria Knoth

    2011-01-01

    to many earlier studies, the results suggest that the timing of income does not matter for long-term child outcomes. This is a reasonable result given the setting in a Scandinavian welfare state with generous child and education subsidies. Actually, later family income (age 12–15) is a more important......I investigate the effects of the timing of family income on child achievement production. Detailed administrative data augmented with Programme for International Student Assessment test scores at age 15 are used to analyze the effects of the timing of family income on child achievement. Contrary...... determinant of child achievement than earlier income....

  15. Contextual Constraint and Preview Time Modulate the Semantic Preview Effect: Evidence from Chinese Sentence Reading.

    Science.gov (United States)

    Li, Nan; Wang, Suiping; Mo, Luxi; Kliegl, Reinhold

    2017-03-23

    Word recognition in sentence reading is influenced by information from both preview and context. Recently, semantic preview effect (SPE) was observed being modulated by the constraint of context, indicating that context might accelerate the processing of semantically related preview words. Besides, SPE was found to depend on preview time, which suggests SPE may change with different processing stages of preview words. Therefore it raises the question of whether preview-time-dependent SPE would be modulated by contextual constraint. In the current study, we investigated the impact of contextual constraint on SPE in Chinese reading, but also examined its dependency on preview time. The preview word and the target word were identical, semantically related, or unrelated to the target word. The results showed a significant three-way interaction: The SPE depended on contextual constraint and preview time. In separate analyses for low and high contextual constraint of target words, the SPE significantly decreased with an increase in preview duration when the target word was of low constraint in the sentence. The effect was numerically in the same direction, but weaker and statistically non-significant when the target word was highly constrained in the sentence. The results indicate that word processing in sentences is a dynamic process of integrating information from both preview (bottom up) and context (top down).

  16. Minimum Time Trajectory Optimization of CNC Machining with Tracking Error Constraints

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2014-01-01

    Full Text Available An off-line optimization approach of high precision minimum time feedrate for CNC machining is proposed. Besides the ordinary considered velocity, acceleration, and jerk constraints, dynamic performance constraint of each servo drive is also considered in this optimization problem to improve the tracking precision along the optimized feedrate trajectory. Tracking error is applied to indicate the servo dynamic performance of each axis. By using variable substitution, the tracking error constrained minimum time trajectory planning problem is formulated as a nonlinear path constrained optimal control problem. Bang-bang constraints structure of the optimal trajectory is proved in this paper; then a novel constraint handling method is proposed to realize a convex optimization based solution of the nonlinear constrained optimal control problem. A simple ellipse feedrate planning test is presented to demonstrate the effectiveness of the approach. Then the practicability and robustness of the trajectory generated by the proposed approach are demonstrated by a butterfly contour machining example.

  17. Foraging constraints reverse the scaling of activity time in carnivores.

    Science.gov (United States)

    Rizzuto, Matteo; Carbone, Chris; Pawar, Samraat

    2017-12-04

    The proportion of time an animal spends actively foraging in a day determines its long-term fitness. Here, we derive a general mathematical model for the scaling of this activity time with body size in consumers. We show that this scaling can change from positive (increasing with size) to negative (decreasing with size) if the detectability and availability of preferred prey sizes is a limiting factor. These predictions are supported by a global dataset on 73 terrestrial carnivore species from 8 families spanning >3 orders of magnitude in size. Carnivores weighing ∼5 kg experience high foraging costs because their diets include significant proportions of relatively small (invertebrate) prey. As a result, they show an increase in activity time with size. This shifts to a negative scaling in larger carnivores as they shift to foraging on less costly vertebrate prey. Our model can be generalized to other classes of terrestrial and aquatic consumers and offers a general framework for mechanistically linking body size to population fitness and vulnerability in consumers.

  18. Observational constraints to boxy/peanut bulge formation time

    Science.gov (United States)

    Pérez, I.; Martínez-Valpuesta, I.; Ruiz-Lara, T.; de Lorenzo-Caceres, A.; Falcón-Barroso, J.; Florido, E.; González Delgado, R. M.; Lyubenova, M.; Marino, R. A.; Sánchez, S. F.; Sánchez-Blázquez, P.; van de Ven, G.; Zurita, A.

    2017-09-01

    Boxy/peanut bulges are considered to be part of the same stellar structure as bars and both could be linked through the buckling instability. The Milky Way is our closest example. The goal of this Letter is to determine if the mass assembly of the different components leaves an imprint in their stellar populations allowing the estimation the time of bar formation and its evolution. To this aim, we use integral field spectroscopy to derive the stellar age distributions, SADs, along the bar and disc of NGC 6032. The analysis clearly shows different SADs for the different bar areas. There is an underlying old (≥12 Gyr) stellar population for the whole galaxy. The bulge shows star formation happening at all times. The inner bar structure shows stars of ages older than 6 Gyr with a deficit of younger populations. The outer bar region presents an SAD similar to that of the disc. To interpret our results, we use a generic numerical simulation of a barred galaxy. Thus, we constrain, for the first time, the epoch of bar formation, the buckling instability period and the posterior growth from disc material. We establish that the bar of NGC 6032 is old, formed around 10 Gyr ago while the buckling phase possibly happened around 8 Gyr ago. All these results point towards bars being long-lasting even in the presence of gas.

  19. Towards provably correct code generation for a hard real-time programming language

    DEFF Research Database (Denmark)

    Fränzle, Martin; Müller-Olm, Markus

    1994-01-01

    This paper sketches a hard real-time programming language featuring operators for expressing timeliness requirements in an abstract, implementation-independent way and presents parts of the design and verification of a provably correct code generator for that language. The notion of implementatio...... correctness used as an implicit specification of the code generator pays attention to timeliness requirements. Hence, formal verification of the code generator design is a guarantee of meeting all deadlines when executing generated code....

  20. Model-based schedulability analysis of safety critical hard real-time Java programs

    DEFF Research Database (Denmark)

    Bøgholm, Thomas; Kragh-Hansen, Henrik; Olsen, Petur

    2008-01-01

    has been implemented in a tool, named SARTS, successfully used to verify the schedulability of a real-time sorting machine consisting of two periodic and two sporadic tasks. SARTS has also been applied on a number of smaller examples to investigate properties of our approach.......In this paper, we present a novel approach to schedulability analysis of Safety Critical Hard Real-Time Java programs. The approach is based on a translation of programs, written in the Safety Critical Java profile introduced in [21] for the Java Optimized Processor [18], to timed automata models...

  1. Detection of Common Problems in Real-Time and Multicore Systems Using Model-Based Constraints

    Directory of Open Access Journals (Sweden)

    Raphaël Beamonte

    2016-01-01

    Full Text Available Multicore systems are complex in that multiple processes are running concurrently and can interfere with each other. Real-time systems add on top of that time constraints, making results invalid as soon as a deadline has been missed. Tracing is often the most reliable and accurate tool available to study and understand those systems. However, tracing requires that users understand the kernel events and their meaning. It is therefore not very accessible. Using modeling to generate source code or represent applications’ workflow is handy for developers and has emerged as part of the model-driven development methodology. In this paper, we propose a new approach to system analysis using model-based constraints, on top of userspace and kernel traces. We introduce the constraints representation and how traces can be used to follow the application’s workflow and check the constraints we set on the model. We then present a number of common problems that we encountered in real-time and multicore systems and describe how our model-based constraints could have helped to save time by automatically identifying the unwanted behavior.

  2. HVM-TP: A Time Predictable, Portable Java Virtual Machine for Hard Real-Time Embedded Systems

    DEFF Research Database (Denmark)

    Luckow, Kasper Søe; Thomsen, Bent; Korsholm, Stephan Erbs

    2014-01-01

    We present HVMTIME; a portable and time predictable JVM implementation with applications in resource-constrained hard real-time embedded systems. In addition, it implements the Safety Critical Java (SCJ) Level 1 specification. Time predictability is achieved by a combination of time predictable...... algorithms, exploiting the programming model of the SCJ specification, and harnessing static knowledge of the hosted SCJ system. This paper presents HVMTIME in terms of its design and capabilities, and demonstrates how a complete timing model of the JVM represented as a Network of Timed Automata can...... be obtained using the tool TetaSARTSJVM. Further, using the timing model, we derive Worst Case Execution Times (WCETs) and Best Case Execution Times (BCETs) of the Java Bytecodes....

  3. Communication Middleware for Distributed Hard Real-Time Systems in Java

    OpenAIRE

    Tejera Carballa, Pablo Daniel

    2012-01-01

    Distributed real-time embedded systems are becoming increasingly important to society. More demands will be made on them and greater reliance will be placed on the delivery of their services. A relevant subset of them is high-integrity or hard real-time systems, where failure can cause loss of life, environmental harm, or significant financial loss. Additionally, the evolution of communication networks and paradigms as well as the necessity of demanding processing power and fault tolerance, mot...

  4. Timing and Spectral Properties of Bright Hard GRBs Observed by Suzaku-WAM

    OpenAIRE

    杉田, 聡司; Sugita, Satoshi; 吉田, 篤正; Yoshida, Atsumasa; 田代, 信; Tashiro, Makoto; 大野, 雅功; Ohno, Masanori; Suzaku/WAM team and HETE-2 team

    2010-01-01

    We report on a detailed comparison between short GRBs and spikes of long GRBs in timing and spectral properties using bright GRBs observed by Suzaku-WAM. We first performed spectral time lag analysis of 217 spikes in 102 bright GRBs. We found a clear proportional correlation between hard/soft lags and widths of spikes for long GRBs, which is smoothly connected with those of short GRBs. We next performed spike-resolved spectral analysis of 63 spikes for 12 long GRBs with known redshifts, using...

  5. Ultrafast Time-Resolved Hard X-Ray Emission Spectroscopy on a Tabletop

    Directory of Open Access Journals (Sweden)

    Luis Miaja-Avila

    2016-09-01

    Full Text Available Experimental tools capable of monitoring both atomic and electronic structure on ultrafast (femtosecond to picosecond time scales are needed for investigating photophysical processes fundamental to light harvesting, photocatalysis, energy and data storage, and optical display technologies. Time-resolved hard x-ray (>3  keV spectroscopies have proven valuable for these measurements due to their elemental specificity and sensitivity to geometric and electronic structures. Here, we present the first tabletop apparatus capable of performing time-resolved x-ray emission spectroscopy. The time resolution of the apparatus is better than 6 ps. By combining a compact laser-driven plasma source with a highly efficient array of microcalorimeter x-ray detectors, we are able to observe photoinduced spin changes in an archetypal polypyridyl iron complex [Fe(2,2^{′}-bipyridine_{3}]^{2+} and accurately measure the lifetime of the quintet spin state. Our results demonstrate that ultrafast hard x-ray emission spectroscopy is no longer confined to large facilities and now can be performed in conventional laboratories with 10 times better time resolution than at synchrotrons. Our results are enabled, in part, by a 100- to 1000-fold increase in x-ray collection efficiency compared to current techniques.

  6. Performance Comparison of EPICS IOC and MARTe in a Hard Real-Time Control Application

    Science.gov (United States)

    Barbalace, Antonio; Manduchi, Gabriele; Neto, A.; De Tommasi, G.; Sartori, F.; Valcarcel, D. F.

    2011-12-01

    EPICS is used worldwide mostly for controlling accelerators and large experimental physics facilities. Although EPICS is well fit for the design and development of automation systems, which are typically VME or PLC-based systems, and for soft real-time systems, it may present several drawbacks when used to develop hard real-time systems/applications especially when general purpose operating systems as plain Linux are chosen. This is in particular true in fusion research devices typically employing several hard real-time systems, such as the magnetic control systems, that may require strict determinism, and high performance in terms of jitter and latency. Serious deterioration of important plasma parameters may happen otherwise, possibly leading to an abrupt termination of the plasma discharge. The MARTe framework has been recently developed to fulfill the demanding requirements for such real-time systems that are alike to run on general purpose operating systems, possibly integrated with the low-latency real-time preemption patches. MARTe has been adopted to develop a number of real-time systems in different Tokamaks. In this paper, we first summarize differences and similarities between EPICS IOC and MARTe. Then we report on a set of performance measurements executed on an x86 64 bit multicore machine running Linux with an IO control algorithm implemented in an EPICS IOC and in MARTe.

  7. Investigating the Effect of Voltage-Switching on Low-Energy Task Scheduling in Hard Real-Time Systems

    National Research Council Canada - National Science Library

    Swaminathan, Vishnu; Chakrabarty, Krishnendu

    2005-01-01

    We investigate the effect of voltage-switching on task execution times and energy consumption for dual-speed hard real-time systems, and present a new approach for scheduling workloads containing periodic tasks...

  8. Efficient constraint handling in electromagnetism-like algorithm for traveling salesman problem with time windows.

    Science.gov (United States)

    Yurtkuran, Alkın; Emel, Erdal

    2014-01-01

    The traveling salesman problem with time windows (TSPTW) is a variant of the traveling salesman problem in which each customer should be visited within a given time window. In this paper, we propose an electromagnetism-like algorithm (EMA) that uses a new constraint handling technique to minimize the travel cost in TSPTW problems. The EMA utilizes the attraction-repulsion mechanism between charged particles in a multidimensional space for global optimization. This paper investigates the problem-specific constraint handling capability of the EMA framework using a new variable bounding strategy, in which real-coded particle's boundary constraints associated with the corresponding time windows of customers, is introduced and combined with the penalty approach to eliminate infeasibilities regarding time window violations. The performance of the proposed algorithm and the effectiveness of the constraint handling technique have been studied extensively, comparing it to that of state-of-the-art metaheuristics using several sets of benchmark problems reported in the literature. The results of the numerical experiments show that the EMA generates feasible and near-optimal results within shorter computational times compared to the test algorithms.

  9. Efficient Constraint Handling in Electromagnetism-Like Algorithm for Traveling Salesman Problem with Time Windows

    Directory of Open Access Journals (Sweden)

    Alkın Yurtkuran

    2014-01-01

    Full Text Available The traveling salesman problem with time windows (TSPTW is a variant of the traveling salesman problem in which each customer should be visited within a given time window. In this paper, we propose an electromagnetism-like algorithm (EMA that uses a new constraint handling technique to minimize the travel cost in TSPTW problems. The EMA utilizes the attraction-repulsion mechanism between charged particles in a multidimensional space for global optimization. This paper investigates the problem-specific constraint handling capability of the EMA framework using a new variable bounding strategy, in which real-coded particle’s boundary constraints associated with the corresponding time windows of customers, is introduced and combined with the penalty approach to eliminate infeasibilities regarding time window violations. The performance of the proposed algorithm and the effectiveness of the constraint handling technique have been studied extensively, comparing it to that of state-of-the-art metaheuristics using several sets of benchmark problems reported in the literature. The results of the numerical experiments show that the EMA generates feasible and near-optimal results within shorter computational times compared to the test algorithms.

  10. Efficient Constraint Handling in Electromagnetism-Like Algorithm for Traveling Salesman Problem with Time Windows

    Science.gov (United States)

    Yurtkuran, Alkın

    2014-01-01

    The traveling salesman problem with time windows (TSPTW) is a variant of the traveling salesman problem in which each customer should be visited within a given time window. In this paper, we propose an electromagnetism-like algorithm (EMA) that uses a new constraint handling technique to minimize the travel cost in TSPTW problems. The EMA utilizes the attraction-repulsion mechanism between charged particles in a multidimensional space for global optimization. This paper investigates the problem-specific constraint handling capability of the EMA framework using a new variable bounding strategy, in which real-coded particle's boundary constraints associated with the corresponding time windows of customers, is introduced and combined with the penalty approach to eliminate infeasibilities regarding time window violations. The performance of the proposed algorithm and the effectiveness of the constraint handling technique have been studied extensively, comparing it to that of state-of-the-art metaheuristics using several sets of benchmark problems reported in the literature. The results of the numerical experiments show that the EMA generates feasible and near-optimal results within shorter computational times compared to the test algorithms. PMID:24723834

  11. Randomized Caches Can Be Pretty Useful to Hard Real-Time Systems

    Directory of Open Access Journals (Sweden)

    Enrico Mezzetti

    2015-03-01

    Full Text Available Cache randomization per se, and its viability for probabilistic timing analysis (PTA of critical real-time systems, are receiving increasingly close attention from the scientific community and the industrial practitioners. In fact, the very notion of introducing randomness and probabilities in time-critical systems has caused strenuous debates owing to the apparent clash that this idea has with the strictly deterministic view traditionally held for those systems. A paper recently appeared in LITES (Reineke, J. (2014. Randomized Caches Considered Harmful in Hard Real-Time Systems. LITES, 1(1, 03:1-03:13. provides a critical analysis of the weaknesses and risks entailed in using randomized caches in hard real-time systems. In order to provide the interested reader with a fuller, balanced appreciation of the subject matter, a critical analysis of the benefits brought about by that innovation should be provided also. This short paper addresses that need by revisiting the array of issues addressed in the cited work, in the light of the latest advances to the relevant state of the art. Accordingly, we show that the potential benefits of randomized caches do offset their limitations, causing them to be - when used in conjunction with PTA - a serious competitor to conventional designs.

  12. Measures to reduce glyphosate runoff from hard surfaces, 2: effect of time interval between application and first precipitation event

    NARCIS (Netherlands)

    Luijendijk, C.D.; Beltman, W.H.J.; Smidt, R.A.; Pas, van der L.J.T.; Kempenaar, C.

    2005-01-01

    In this research the effect of moisture conditions of hard surfaces on emission of herbicides from hard surfaces was quantified. In addition the dissipation of glyphosate applied on brick-pavement is determined in time. The outdoor experiment was carried out on 3 and 17 June 2003. In previous

  13. Discretionary time of Chinese college students: Activities and impact of SARS-induced constraints on choices

    Science.gov (United States)

    He Yang; Susan Hutchinson; Harry Zinn; Alan Watson

    2011-01-01

    How people make choices about activity engagement during discretionary time is a topic of increasing interest to those studying quality of life issues. Assuming choices are made to maximize individual welfare, several factors are believed to influence these choices. Constraints theory from the leisure research literature suggests these choices are heavily influenced by...

  14. Discretionary Time of Chinese College Students: Activities and Impact of SARS-Induced Constraints on Choices

    Science.gov (United States)

    Yang, He; Hutchinson, Susan; Zinn, Harry; Watson, Alan

    2011-01-01

    How people make choices about activity engagement during discretionary time is a topic of increasing interest to those studying quality of life issues. Assuming choices are made to maximize individual welfare, several factors are believed to influence these choices. Constraints theory from the leisure research literature suggests these choices are…

  15. Attention and time constraints in perceptual-motor learning and performance: Instruction, analogy, and skill level

    NARCIS (Netherlands)

    Koedijker, J.M.; Poolton, J.M.; Maxwell, J.P.; Oudejans, R.R.D.; Beek, P.J.; Masters, R.S.W.

    2011-01-01

    We sought to gain more insight into the effects of attention focus and time constraints on skill learning and performance in novices and experts by means of two complementary experiments using a table tennis paradigm. Experiment 1 showed that skill-focus conditions and slowed ball frequency

  16. Output regulation of discrete-time linear plants subject to state and input constraints

    NARCIS (Netherlands)

    Shi, Guoyong; Saberi, Ali; Stoorvogel, Antonie Arij; Sannuti, Peddapullaiah

    2003-01-01

    Discrete-time output regulation of linear systems with state and/or input constraints on magnitude is considered. Structural properties of linear plants are identified under which the so-called constrained semi-global and global output regulation problems are solvable. As in the case of

  17. Private sector involvement in times of armed conflict: What are the constraints for trading medical equipment?

    Science.gov (United States)

    Schmidt, Georg

    Today, healthcare facilities are highly dependent on the private sector to keep their medical equipment functioning. Moreover, private sector involvement becomes particularly important for the supply of spare parts and consumables. However, in times of armed conflict, the capacity of the corporate world appears to be seriously hindered. Subsequently, this study researches the influence of armed conflict on the private medical equipment sector. This study follows a qualitative approach by conducting 19 interviews with representatives of the corporate world in an active conflict zone. A semistructured interview guide, consisting of 10 questions, was used to examine the constraints of this sector. The results reveal that the lack of skilled personnel, complicated importation procedures, and a decrease in financial capacity are the major constraints faced by private companies dealing in medical equipment in conflict zones. Even when no official sanctions and embargoes for medical items exist, constraints for trading medical equipment are clearly recognizable. Countries at war would benefit from a centralized structure that deals with the importation procedures for medical items, to assist local companies in their purchasing procedures. A high degree of adaption is needed to continue operating, despite the emerging constraints of armed conflict. Future studies might research the constraints for manufacturers outside the conflict to export medical items to the country of war.

  18. Walking to the beat of their own drum: how children and adults meet timing constraints.

    Science.gov (United States)

    Gill, Simone V

    2015-01-01

    Walking requires adapting to meet task constraints. Between 5- and 7-years old, children's walking approximates adult walking without constraints. To examine how children and adults adapt to meet timing constraints, 57 5- to 7-year olds and 20 adults walked to slow and fast audio metronome paces. Both children and adults modified their walking. However, at the slow pace, children had more trouble matching the metronome compared to adults. The youngest children's walking patterns deviated most from the slow metronome pace, and practice improved their performance. Five-year olds were the only group that did not display carryover effects to the metronome paces. Findings are discussed in relation to what contributes to the development of adaptation in children.

  19. Exponential-Time Algorithms and Complexity of NP-Hard Graph Problems

    DEFF Research Database (Denmark)

    Taslaman, Nina Sofia

    NP-hard problems are deemed highly unlikely to be solvable in polynomial time. Still, one can often find algorithms that are substantially faster than brute force solutions. This thesis concerns such algorithms for problems from graph theory; techniques for constructing and improving this type...... to a polylogarithmic factor in the exponent. For planar graphs, lower bounds are found by examining and combining existing reductions. An asymptotically tight bound is found for points corresponding to evaluation of the 3-state Potts model partition function; for remaining points the obtained lower bounds...

  20. Time-optimal spacecraft attitude maneuver path planning under boundary and pointing constraints

    Science.gov (United States)

    Wu, Changqing; Xu, Rui; Zhu, Shengying; Cui, Pingyuan

    2017-08-01

    The rapid large angle attitude maneuver capability of spacecraft is required during many space missions. This paper addresses the challenge of time-optimal spacecraft attitude maneuver under boundary and pointing constraints. From the perspective of the optimal time, the constrained attitude maneuver problem is summarized as an optimum path-planning problem. To address this problem, a metaheuristic maneuver path planning method is proposed, Angular velocity-Time Coding Differential Evolution (ATDE). In the ATDE method, the angular velocity and time are coded for attitude maneuver modeling, which increases the number of variables and results in a high-dimensional problem. In order to deal with this problem, differential evolution is employed to perform variation and evolution. The boundary and pointing constraints are constructed into the fitness function for path evaluation. Finally, numerical simulations for the different cases were performed to validate the feasibility and effectiveness of the proposed method.

  1. Necessary N-representability Constraints from Time-reversal Symmetry for Periodic Systems

    CERN Document Server

    Rubin, Nicholas C

    2016-01-01

    The variational calculation of the two-electron reduced density matrix (2-RDM) is extended to periodic molecular systems. If the 2-RDM theory is extended to the periodic case without consideration of time-reversal symmetry, however, it can yields energies that are significantly lower than the correct energies. We derive and implement linear constraints that enforce time-reversal symmetry on the 2-RDM without destroying its computationally favorable block-diagonal structure from translational invariance. Time-reversal symmetry is distinct from space-group or spin (SU(2)) symmetries which can be expressed by unitary transformations. The time-reversal symmetry constraints are demonstrated through calculations of the metallic hydrogen chain and the one-dimensional lithium hydride crystal.

  2. Constraints on silicates formation in the Si-Al-Fe system: Application to hard deposits in steam generators of PWR nuclear reactors

    Science.gov (United States)

    Berger, Gilles; Million-Picallion, Lisa; Lefevre, Grégory; Delaunay, Sophie

    2015-04-01

    Introduction: The hydrothermal crystallization of silicates phases in the Si-Al-Fe system may lead to industrial constraints that can be encountered in the nuclear industry in at least two contexts: the geological repository for nuclear wastes and the formation of hard sludges in the steam generator of the PWR nuclear plants. In the first situation, the chemical reactions between the Fe-canister and the surrounding clays have been extensively studied in laboratory [1-7] and pilot experiments [8]. These studies demonstrated that the high reactivity of metallic iron leads to the formation of Fe-silicates, berthierine like, in a wide range of temperature. By contrast, the formation of deposits in the steam generators of PWR plants, called hard sludges, is a newer and less studied issue which can affect the reactor performance. Experiments: We present here a preliminary set of experiments reproducing the formation of hard sludges under conditions representative of the steam generator of PWR power plant: 275°C, diluted solutions maintained at low potential by hydrazine addition and at alkaline pH by low concentrations of amines and ammoniac. Magnetite, a corrosion by-product of the secondary circuit, is the source of iron while aqueous Si and Al, the major impurities in this system, are supplied either as trace elements in the circulating solution or by addition of amorphous silica and alumina when considering confined zones. The fluid chemistry is monitored by sampling aliquots of the solution. Eh and pH are continuously measured by hydrothermal Cormet© electrodes implanted in a titanium hydrothermal reactor. The transformation, or not, of the solid fraction was examined post-mortem. These experiments evidenced the role of Al colloids as precursor of cements composed of kaolinite and boehmite, and the passivation of amorphous silica (becoming unreactive) likely by sorption of aqueous iron. But no Fe-bearing was formed by contrast to many published studies on the Fe

  3. Evaluation of human muscle hardness after dynamic exercise with ultrasound real-time tissue elastography: a feasibility study.

    Science.gov (United States)

    Yanagisawa, O; Niitsu, M; Kurihara, T; Fukubayashi, T

    2011-09-01

    To assess the feasibility of ultrasound real-time tissue elastography (RTE) for measuring exercise-induced changes in muscle hardness and to compare the findings of RTE with those of a tissue hardness meter for semi-quantitative assessment of the hardness of exercised muscles. Nine male participants performed an arm-curl exercise. RTE measurements were performed by manually applying repetitive compression with the transducer on the scan position before exercise, immediately after exercise, and at 30 min after exercise; strain ratios between muscle and a reference material (hydrogel) were calculated (muscle strain/material strain). A tissue hardness meter was also used to evaluate muscle hardness. The intraclass correlation coefficients (ICCs) for the three repeated measurements at each measurement time were calculated to evaluate the intra-observer reproducibility of each technique. Immediately after exercise, the strain ratio and the value obtained using the tissue hardness meter significantly decreased (from 1.65 to 1.35) and increased (from 51.8 to 54.3), respectively. Both parameters returned to their pre-exercise value 30 min after exercise. The ICCs of the RTE (and the ICCs of the muscle hardness meter) were 0.971 (0.816) before exercise, 0.939 (0.776) immediately after exercise, and 0.959 (0.882) at 30 min after exercise. Similar to the muscle hardness meter, RTE revealed the exercise-induced changes of muscle hardness semi-quantitatively. The intra-observer reproducibility of RTE was very high at each measurement time. These findings suggest that RTE is a clinically useful technique for assessing hardness of specific exercised muscles. Copyright © 2011 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  4. Selection of the optimal hard facing (HF technology of damaged forging dies based on cooling time t8/5

    Directory of Open Access Journals (Sweden)

    D. Arsić

    2016-01-01

    Full Text Available In exploitation, the forging dies are exposed to heating up to very high temperatures, variable loads: compressive, impact and shear. In this paper, the reparatory hard facing of the damaged forging dies is considered. The objective was to establish the optimal reparatory technology based on cooling time t8/5 . The verification of the adopted technology was done by investigation of the hard faced layers microstructure and measurements of hardness within the welded layers’ characteristic zones. Cooling time was determined theoretically, numerically and experimentally.

  5. Timing Analysis of Mixed-Criticality Hard Real-Time Applications Implemented on Distributed Partitioned Architectures

    DEFF Research Database (Denmark)

    Marinescu, Sorin Ovidiu; Tamas-Selicean, Domitian; Acretoaie, Vlad

    In this paper we are interested in the timing analysis of mixed-criticality embedded real-time applications mapped on distributed heterogeneous architectures. Mixedcriticality tasks can be integrated onto the same architecture only if there is enough spatial and temporal separation among them. We...... in partitions using fixedpriority preemptive scheduling. We have extended the stateof- the-art algorithms for schedulability analysis to take into account the partitions. The proposed algorithm has been evaluated using several synthetic and real-life benchmarks....

  6. Soft and hard computing approaches for real-time prediction of currents in a tide-dominated coastal area

    Digital Repository Service at National Institute of Oceanography (India)

    Charhate, S.B.; Deo, M.C.; SanilKumar, V.

    ), as well as the hard mathematical approaches of stochastic and statistical methods. The suggested schemes use only a univariate time series of currents to forecast their future values. The measurements of coastal currents made at two locations in the Gulf...

  7. Local constraints on cosmic string loops from photometry and pulsar timing

    Science.gov (United States)

    Pshirkov, M. S.; Tuntsov, A. V.

    2010-04-01

    We constrain the cosmological density of cosmic string loops using two observational signatures—gravitational microlensing and the Kaiser-Stebbins effect. Photometry from RXTE and CoRoT space missions and pulsar timing from Parkes Pulsar Timing Array, Arecibo and Green Bank radio telescopes allow us to probe cosmic strings in a wide range of tensions Gμ/c2=10-16÷10-10. We find that pulsar timing data provide the most stringent constraints on the abundance of light strings at the level Ωs˜10-3. Future observational facilities such as the Square Kilometer Array will allow one to improve these constraints by orders of magnitude.

  8. Hard Times for HRD, Lean Times for Learning?: Workplace Participatory Practices as Enablers of Learning

    Science.gov (United States)

    Warhurst, Russell

    2013-01-01

    Purpose: This article aims to show how in times of austerity when formal HRD activity is curtailed and yet the need for learning is greatest, non-formal learning methods such as workplace involvement and participation initiated by line managers can compensate by enabling the required learning and change. Design/methodology/approach: A qualitative…

  9. Testing deformation hypotheses by constraints on a time series of geodetic observations

    Science.gov (United States)

    Velsink, Hiddo

    2018-01-01

    In geodetic deformation analysis observations are used to identify form and size changes of a geodetic network, representing objects on the earth's surface. The network points are monitored, often continuously, because of suspected deformations. A deformation may affect many points during many epochs. The problem is that the best description of the deformation is, in general, unknown. To find it, different hypothesised deformation models have to be tested systematically for agreement with the observations. The tests have to be capable of stating with a certain probability the size of detectable deformations, and to be datum invariant. A statistical criterion is needed to find the best deformation model. Existing methods do not fulfil these requirements. Here we propose a method that formulates the different hypotheses as sets of constraints on the parameters of a least-squares adjustment model. The constraints can relate to subsets of epochs and to subsets of points, thus combining time series analysis and congruence model analysis. The constraints are formulated as nonstochastic observations in an adjustment model of observation equations. This gives an easy way to test the constraints and to get a quality description. The proposed method aims at providing a good discriminating method to find the best description of a deformation. The method is expected to improve the quality of geodetic deformation analysis. We demonstrate the method with an elaborate example.

  10. Effect of Ball Milling Time on Microstructure and Hardness of Porous Magnesium/Carbon Nanofiber Composites

    Science.gov (United States)

    Xu, Huiru; Zou, Ning; Li, Qizhen

    2017-07-01

    Porous magnesium/carbon nanofiber composites were produced using a powder metallurgic method to study the effect of ball milling time on their microstructure and hardness. Three ball milling times (240 min, 320 min, and 480 min) and two carbon nanofiber concentrations (0.05% and 1%) were utilized in the production of these porous composites. The increase of ball milling time led to the gradual decrease of the average size of magnesium powders from the initial 40 µm to about 26 µm after 480 min of ball milling. The powder size range first increased with the increase of ball milling time from 240 min to 320 min, and then decreased with the further increase of ball milling time to 480 min. Among the three ball milling times, the produced porous composites from the powders after 320 min of ball milling have the largest average pore size. With the increase of ball milling time from 240 min to 320 min and then to 480 min, the average Vickers microhardness data first decreased and then increased for Mg-1%C porous composites along the cross-sections parallel to the compact processing direction, increased for the cross-sections perpendicular to the compact processing direction for Mg-1%C porous composites, first increased and then decreased for the cross-sections parallel to the compact processing direction for Mg-0.05%C porous composites, and slightly decreased for the cross-sections perpendicular to the compact processing direction for Mg-0.05%C porous composites.

  11. Hard Real-Time Task Scheduling in Cloud Computing Using an Adaptive Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Amjad Mahmood

    2017-04-01

    Full Text Available In the Infrastructure-as-a-Service cloud computing model, virtualized computing resources in the form of virtual machines are provided over the Internet. A user can rent an arbitrary number of computing resources to meet their requirements, making cloud computing an attractive choice for executing real-time tasks. Economical task allocation and scheduling on a set of leased virtual machines is an important problem in the cloud computing environment. This paper proposes a greedy and a genetic algorithm with an adaptive selection of suitable crossover and mutation operations (named as AGA to allocate and schedule real-time tasks with precedence constraint on heterogamous virtual machines. A comprehensive simulation study has been done to evaluate the performance of the proposed algorithms in terms of their solution quality and efficiency. The simulation results show that AGA outperforms the greedy algorithm and non-adaptive genetic algorithm in terms of solution quality.

  12. Extending models for two-dimensional constraints

    DEFF Research Database (Denmark)

    Forchhammer, Søren

    2009-01-01

    for models of two-dimensional constraints and as examples we apply it to the hard-square constraint and the no isolated bits (n.i.b) constraint. The iterative scaling can ensure that the entropy of the extension is optimized and that the entropy is increased compared to the initial model defined on 2 times 2...... elements. Application to a simple stationary model with hidden states is also outlined. For the n.i.b constraint, the initial model is based on elements defined by blocks of (1 times 2) binary symbols....

  13. Discrete-Time Indefinite Stochastic Linear Quadratic Optimal Control with Second Moment Constraints

    Directory of Open Access Journals (Sweden)

    Weihai Zhang

    2014-01-01

    Full Text Available This paper studies the discrete-time stochastic linear quadratic (LQ problem with a second moment constraint on the terminal state, where the weighting matrices in the cost functional are allowed to be indefinite. By means of the matrix Lagrange theorem, a new class of generalized difference Riccati equations (GDREs is introduced. It is shown that the well-posedness, and the attainability of the LQ problem and the solvability of the GDREs are equivalent to each other.

  14. Effect of exercise-induced muscle damage on muscle hardness evaluated by ultrasound real-time tissue elastography

    OpenAIRE

    Yanagisawa, Osamu; Sakuma, Jun; Kawakami, Yasuo; Suzuki, Katsuhiko; Fukubayashi, Toru

    2015-01-01

    Purpose To assess the effect of exercise-induced muscle damage on muscle hardness and evaluate the relationship between muscle hardness and muscle damage indicators. Methods Seven men (mean 25.3?years; 172.7?cm; 66.8?kg) performed the single-leg ankle plantar flexion exercise involving both concentric and eccentric contractions (10 sets of 40 repetitions). The hardness of the medial gastrocnemius (MG) was evaluated using ultrasound real-time tissue elastography before, from day 1 to 4, and da...

  15. Choosing the Most Effective Pattern Classification Model under Learning-Time Constraint.

    Directory of Open Access Journals (Sweden)

    Priscila T M Saito

    Full Text Available Nowadays, large datasets are common and demand faster and more effective pattern analysis techniques. However, methodologies to compare classifiers usually do not take into account the learning-time constraints required by applications. This work presents a methodology to compare classifiers with respect to their ability to learn from classification errors on a large learning set, within a given time limit. Faster techniques may acquire more training samples, but only when they are more effective will they achieve higher performance on unseen testing sets. We demonstrate this result using several techniques, multiple datasets, and typical learning-time limits required by applications.

  16. Proximal and time-varying effects of cigarette, alcohol, marijuana and other hard drug use on adolescent dating aggression.

    Science.gov (United States)

    McNaughton Reyes, H Luz; Foshee, Vangie A; Bauer, Daniel J; Ennett, Susan T

    2014-04-01

    Although numerous studies have established a link between substance use and adult partner violence, little research has examined the relationship during adolescence and most extant research has not examined multiple substance use types. The current study used hierarchical growth modeling to simultaneously examine proximal (between-person) and time-varying (within-person) relations between cigarette, alcohol, marijuana and hard drug use and physical dating aggression across grades 8 through 12 while controlling for demographic covariates and shared risk factors. Proximal effects of marijuana use on dating aggression were found for girls and proximal effects of hard drug use on dating aggression were found for boys. Time-varying effects were found for alcohol for both boys and girls and for hard drug use for boys only. Overall, findings suggest that alcohol, marijuana and hard drug use predict whether and when adolescents engage in dating aggression and should be targeted by prevention interventions. Published by Elsevier Ltd.

  17. Alternative Forms of Resilience Confronting Hard Economic Times. A South European Perspective

    Directory of Open Access Journals (Sweden)

    Maria Kousis

    2017-05-01

    Full Text Available The aim of this special issue is to contribute to the study of alternative forms of resilience, visible in the economic and noneconomic activities of citizens confronting hard economic times and falling rights in Italy, Spain, Greece and Portugal, since the global financial crisis of 2008. It does so through a set of recent empirical studies which adopt recent theoretical approaches, such as Social Innovation or Sustainable Community Movement Organizations, and offer new evidence on solidarity oriented practices, including their links to social movement activism. The authors of this special issue contribute to the existing recent debates by highlighting key features of alternative forms of resilience, their links to social movements and theoretical orientations influenced by social movement and resilience studies in four Southern European countries and regions.

  18. Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources

    Energy Technology Data Exchange (ETDEWEB)

    Rutherford, Michael E.; Chapman, David J.; White, Thomas G. [Imperial College London, London (United Kingdom); Drakopoulos, Michael [Diamond Light Source, I12 Joint Engineering, Environmental, Processing (JEEP) Beamline, Didcot, Oxfordshire (United Kingdom); Rack, Alexander [European Synchrotron Radiation Facility, Grenoble (France); Eakins, Daniel E., E-mail: d.eakins@imperial.ac.uk [Imperial College London, London (United Kingdom)

    2016-03-24

    Scintillator performance in time-resolved, hard, indirect detection X-ray studies on the sub-microsecond timescale at synchrotron light sources is reviewed, modelled and examined experimentally. LYSO:Ce is found to be the only commercially available crystal suitable for these experiments. The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits)

  19. Rigid Body Time Integration by Convected Base Vectors with Implicit Constraints

    DEFF Research Database (Denmark)

    Krenk, Steen; Nielsen, Martin Bjerre

    2013-01-01

    A conservative time integration algorithm based on a convected set of orthonormal base vectors is presented. The equations of motion are derived from an extended Hamiltonian formulation, combining the components of the three base vectors with a set of orthonormality constraints. The particular form...... of the kinetic energy used in the present formulation is deliberately chosen to correspond to a rigid body rotation, and the orthonormality constraints are introduced via the equivalent Green strain components of the base vectors. The particular form of the extended inertia tensor used here implies a set....... The differential equations of motion are recast into discrete form using a suitable combination of mean values and increments, which is identified by considering a finite increment of the Hamiltonian. Examples illustrate the accuracy and conservation properties of the algorithm....

  20. An experimental test on time constraint and sexual conflict over parental care.

    Science.gov (United States)

    Griggio, Matteo

    2015-09-01

    Because parental care is costly, a sexual conflict between parents over parental investment is expected to arise. Parental care behavior is an adaptive decision, involving trade-offs between remating, and consequently desertion of the brood, and continuing parental effort. If the main advantage of desertion is remating, then this will be a time constraint, because the deserting individual will require a certain minimum period of time to breed again in the same breeding season. So, a short breeding season should force certain individuals to desert the first brood to have enough time to successfully complete their second breeding attempt. The rock sparrow, Petronia petronia, is an unusual species in which brood desertion can occur in both sexes and the breeding season is quite short so it is a good species to investigate the role of time constraint on brood desertion. For 3 years, I investigated the brood desertion modality of the rock sparrow. Then, for 2 years, I removed a group of experimental nest boxes during the autumn. Later, I re-installed the experimental nest boxes after the start of the breeding season (2 weeks after the first egg was laid), mimicking a shortening of the breeding season for the (experimental) pairs that used experimental nest boxes. I found that in the experimental pairs, the percentage of deserting individuals was significantly higher than in the control groups, and the deserting individuals were older females. This experiment adds to our knowledge of timing of reproduction effects on individual decisions to desert by showing that a short and delayed breeding season may have different effects on males and females. To my knowledge, this is the first experimental study that demonstrates a direct link between time constraint and brood desertion.

  1. Differential Responses for Harvesting Times and Storage on Hardness of Different Varieties of Okra

    Directory of Open Access Journals (Sweden)

    Ghadir MOHAMMADI

    2011-11-01

    Full Text Available Okra seed hardness results in slow and nonuniform germination. This study was conducted to determine the effects of time of harvest and storage on seed germination of four different cultivars of okra (Abelmoschus esculentus L.. The study was carried out at Agricultural faculty of Razi University in years 2009 and 2010. The experimental design was a randomized complete block under factorial arrangement with three replications. Four different cultivars of okra included, Boiatloy, Beloudo, Clemsson Seinless and Pleas and six harvesting times of 20-25-30-35-40 and 50 days after flowering were considered in the present study. The results showed that seed germination increased in 2009 from 3.4%, at first harvesting time, to 46.4% at fifth harvesting time, and in 2010 from 2.9%, at the first harvesting time, to 49.7% at fifth harvesting time. Different cultivars varied in seed germination. In 2009 Plea and in 2010 Clemson cultivars showed the highest germination. Seeds from different parts of the plant also showed different germination rate. In 2009 seeds from the middle part of the plant with 54.3% and in 2010 seed from the lower part with 50.3 % showed the highest germination. In 2009 seeds from the lower part of pod showed more germination, whereas in 2010 seeds from middle part of pod produced higher germination. By increasing time to harvest, the percentage of seed germination after storage highly increased. Different cultivars during storage showed different behaviors on germination. Beloudo cultivar produced more seed germination than other varieties after storage, and Pleas after storage produced lower seed germination. Seeds from the middle part of plant and middle part of pod showed a higher germination after storage.

  2. Differential Responses for Harvesting Times and Storage on Hardness of Different Varieties of Okra

    Directory of Open Access Journals (Sweden)

    Ghadir MOHAMMADI

    2011-11-01

    Full Text Available Okra seed hardness results in slow and nonuniform germination. This study was conducted to determine the effects of time of harvest and storage on seed germination of four different cultivars of okra (Abelmoschus esculentus L.. The study was carried out at Agricultural faculty of Razi University in years 2009 and 2010. The experimental design was a randomized complete block under factorial arrangement with three replications. Four different cultivars of okra included, �Boiatloy�, �Beloudo�, �Clemsson Seinless� and �Pleas� and six harvesting times of 20-25-30-35-40 and 50 days after flowering were considered in the present study. The results showed that seed germination increased in 2009 from 3.4%, at first harvesting time, to 46.4% at fifth harvesting time, and in 2010 from 2.9%, at the first harvesting time, to 49.7% at fifth harvesting time. Different cultivars varied in seed germination. In 2009 �Plea� and in 2010 �Clemson� cultivars showed the highest germination. Seeds from different parts of the plant also showed different germination rate. In 2009 seeds from the middle part of the plant with 54.3% and in 2010 seed from the lower part with 50.3 % showed the highest germination. In 2009 seeds from the lower part of pod showed more germination, whereas in 2010 seeds from middle part of pod produced higher germination. By increasing time to harvest, the percentage of seed germination after storage highly increased. Different cultivars during storage showed different behaviors on germination. �Beloudo� cultivar produced more seed germination than other varieties after storage, and �Pleas� after storage produced lower seed germination. Seeds from the middle part of plant and middle part of pod showed a higher germination after storage.

  3. A Novel Spatial-Temporal Voronoi Diagram-Based Heuristic Approach for Large-Scale Vehicle Routing Optimization with Time Constraints

    Directory of Open Access Journals (Sweden)

    Wei Tu

    2015-10-01

    Full Text Available Vehicle routing optimization (VRO designs the best routes to reduce travel cost, energy consumption, and carbon emission. Due to non-deterministic polynomial-time hard (NP-hard complexity, many VROs involved in real-world applications require too much computing effort. Shortening computing time for VRO is a great challenge for state-of-the-art spatial optimization algorithms. From a spatial-temporal perspective, this paper presents a spatial-temporal Voronoi diagram-based heuristic approach for large-scale vehicle routing problems with time windows (VRPTW. Considering time constraints, a spatial-temporal Voronoi distance is derived from the spatial-temporal Voronoi diagram to find near neighbors in the space-time searching context. A Voronoi distance decay strategy that integrates a time warp operation is proposed to accelerate local search procedures. A spatial-temporal feature-guided search is developed to improve unpromising micro route structures. Experiments on VRPTW benchmarks and real-world instances are conducted to verify performance. The results demonstrate that the proposed approach is competitive with state-of-the-art heuristics and achieves high-quality solutions for large-scale instances of VRPTWs in a short time. This novel approach will contribute to spatial decision support community by developing an effective vehicle routing optimization method for large transportation applications in both public and private sectors.

  4. Effects of health and social care spending constraints on mortality in England: a time trend analysis.

    Science.gov (United States)

    Watkins, Johnathan; Wulaningsih, Wahyu; Da Zhou, Charlie; Marshall, Dominic C; Sylianteng, Guia D C; Dela Rosa, Phyllis G; Miguel, Viveka A; Raine, Rosalind; King, Lawrence P; Maruthappu, Mahiben

    2017-11-15

    Since 2010, England has experienced relative constraints in public expenditure on healthcare (PEH) and social care (PES). We sought to determine whether these constraints have affected mortality rates. We collected data on health and social care resources and finances for England from 2001 to 2014. Time trend analyses were conducted to compare the actual mortality rates in 2011-2014 with the counterfactual rates expected based on trends before spending constraints. Fixed-effects regression analyses were conducted using annual data on PES and PEH with mortality as the outcome, with further adjustments for macroeconomic factors and resources. Analyses were stratified by age group, place of death and lower-tier local authority (n=325). Mortality rates to 2020 were projected based on recent trends. Spending constraints between 2010 and 2014 were associated with an estimated 45 368 (95% CI 34 530 to 56 206) higher than expected number of deaths compared with pre-2010 trends. Deaths in those aged ≥60 and in care homes accounted for the majority. PES was more strongly linked with care home and home mortality than PEH, with each £10 per capita decline in real PES associated with an increase of 5.10 (3.65-6.54) (pconstraints, especially PES, are associated with a substantial mortality gap. We suggest that spending should be targeted on improving care delivered in care homes and at home; and maintaining or increasing nurse numbers. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  5. Hard real-time closed-loop electrophysiology with the Real-Time eXperiment Interface (RTXI.

    Directory of Open Access Journals (Sweden)

    Yogi A Patel

    2017-05-01

    Full Text Available The ability to experimentally perturb biological systems has traditionally been limited to static pre-programmed or operator-controlled protocols. In contrast, real-time control allows dynamic probing of biological systems with perturbations that are computed on-the-fly during experimentation. Real-time control applications for biological research are available; however, these systems are costly and often restrict the flexibility and customization of experimental protocols. The Real-Time eXperiment Interface (RTXI is an open source software platform for achieving hard real-time data acquisition and closed-loop control in biological experiments while retaining the flexibility needed for experimental settings. RTXI has enabled users to implement complex custom closed-loop protocols in single cell, cell network, animal, and human electrophysiology studies. RTXI is also used as a free and open source, customizable electrophysiology platform in open-loop studies requiring online data acquisition, processing, and visualization. RTXI is easy to install, can be used with an extensive range of external experimentation and data acquisition hardware, and includes standard modules for implementing common electrophysiology protocols.

  6. Real-Time Adaptation to Time-Varying Constraints for Medical Video Communications.

    Science.gov (United States)

    Antoniou, Zinonas C; Panayides, Andreas S; Pantziaris, Marios; Constantinides, Anthony G; Pattichis, Constantinos S; Pattichis, Marios S

    2017-07-12

    The wider adoption of mobile Health (mHealth) video communication systems in standard clinical practice requires real-time control to provide for adequate levels of clinical video quality to support reliable diagnosis. The latter can only be achieved with real-time adaptation to time-varying wireless networks' state to guarantee clinically acceptable performance throughout the streaming session, while conforming to device capabilities for supporting real-time encoding.

  7. Hard real-time multibody simulations using ARM-based embedded systems

    Energy Technology Data Exchange (ETDEWEB)

    Pastorino, Roland, E-mail: roland.pastorino@kuleuven.be, E-mail: rpastorino@udc.es; Cosco, Francesco, E-mail: francesco.cosco@kuleuven.be; Naets, Frank, E-mail: frank.naets@kuleuven.be; Desmet, Wim, E-mail: wim.desmet@kuleuven.be [KU Leuven, PMA division, Department of Mechanical Engineering (Belgium); Cuadrado, Javier, E-mail: javicuad@cdf.udc.es [Universidad de La Coruña, Laboratorio de Ingeniería Mecánica (Spain)

    2016-05-15

    The real-time simulation of multibody models on embedded systems is of particular interest for controllers and observers such as model predictive controllers and state observers, which rely on a dynamic model of the process and are customarily executed in electronic control units. This work first identifies the software techniques and tools required to easily write efficient code for multibody models to be simulated on ARM-based embedded systems. Automatic Programming and Source Code Translation are the two techniques that were chosen to generate source code for multibody models in different programming languages. Automatic Programming is used to generate procedural code in an intermediate representation from an object-oriented library and Source Code Translation is used to translate the intermediate representation automatically to an interpreted language or to a compiled language for efficiency purposes. An implementation of these techniques is proposed. It is based on a Python template engine and AST tree walkers for Source Code Generation and on a model-driven translator for the Source Code Translation. The code is translated from a metalanguage to any of the following four programming languages: Python-Numpy, Matlab, C++-Armadillo, C++-Eigen. Two examples of multibody models were simulated: a four-bar linkage with multiple loops and a 3D vehicle steering system. The code for these examples has been generated and executed on two ARM-based single-board computers. Using compiled languages, both models could be simulated faster than real-time despite the low resources and performance of these embedded systems. Finally, the real-time performance of both models was evaluated when executed in hard real-time on Xenomai for both embedded systems. This work shows through measurements that Automatic Programming and Source Code Translation are valuable techniques to develop real-time multibody models to be used in embedded observers and controllers.

  8. Influence of Ambient Stressors and Time Constraints on Diagnostic Accuracy of Borderline Pigmented Skin Lesions.

    Science.gov (United States)

    Feci, Luca; Cevenini, Gabriele; Nami, Niccolò; Fagiolini, Alberto; Perotti, Roberto; Miracco, Clelia; Fimiani, Michele; Rubegni, Pietro

    2015-01-01

    Health professionals are required to make complex decisions in dynamic contexts involving many variables and factors. Decisions are more difficult in the presence of uncertainty, urgency and high risk. To evaluate the effect of ambient stressors and time constraints on decision making by expert dermatologists faced with borderline pigmented skin lesions (PSL) (early melanoma vs. atypical nevi). We performed a retrospective chart review of PSL from the image databases of our department. A total of 321 PSL (219 nevi and 102 melanomas) were randomly assigned to three groups: control group, ambient stress group and time stress group. The diagnostic accuracy of each group was evaluated as sensitivity and specificity. Mean sensitivity and specificity of diagnosis were 69.2 and 90.5% in the control group, 62 and 81.2% in the ambient stress group and 59.6 and 82.5% in the time stress group, respectively. Time constraints and stressors negatively influenced the performance of dermatologists in the diagnosis of atypical PSL. © 2015 S. Karger AG, Basel.

  9. Possibilities of implementation of synchronous Ethernet in popular Ethernet version using timing and interference constraints

    Directory of Open Access Journals (Sweden)

    Seetaiah KILARU

    2015-12-01

    Full Text Available Popular network architectures are following packet based architectures instead of conventional Time division multiplexing. The existed Ethernet is basically asynchronous in nature and was not designed based on timing transfer constraints. To achieve the challenge of next generation network with respect to efficient bandwidth and faster data rates, we have to deploy the network which has less latency. This can be achieved by Synchronous Ethernet (SyncE. In Sync-E, Phase Locked Loop (PLL was used to recover the incoming jitter from clock recovery circuit. Then feed the PLL block to transmission device. We have to design the network in an unaffected way that the functions of Ethernet should run in normal way even we introduced timing path at physical layer. This paper will give detailed outlook on how Sync-E is achieved from Asynchronous format. Reference model of 100 Base-TX/FX was analyzed with respect to timing and interference constraints. Finally, it was analyzed with the data rate improvement with the proposed method.

  10. AN INVESTIGATION OF LEG AND TRUNK STRENGTH AND REACTION TIMES OF HARD-STYLE MARTIAL ARTS PRACTITIONERS

    OpenAIRE

    Oliver O'Donovan; Jeanette Cheung; Maria Catley; Alison H. McGregor; Paul H. Strutton

    2006-01-01

    The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT), choice reaction times (CRT) and movement times (MT). Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response...

  11. The Optimization of Transportation Costs in Logistics Enterprises with Time-Window Constraints

    Directory of Open Access Journals (Sweden)

    Qingyou Yan

    2015-01-01

    Full Text Available This paper presents a model for solving a multiobjective vehicle routing problem with soft time-window constraints that specify the earliest and latest arrival times of customers. If a customer is serviced before the earliest specified arrival time, extra inventory costs are incurred. If the customer is serviced after the latest arrival time, penalty costs must be paid. Both the total transportation cost and the required fleet size are minimized in this model, which also accounts for the given capacity limitations of each vehicle. The total transportation cost consists of direct transportation costs, extra inventory costs, and penalty costs. This multiobjective optimization is solved by using a modified genetic algorithm approach. The output of the algorithm is a set of optimal solutions that represent the trade-off between total transportation cost and the fleet size required to service customers. The influential impact of these two factors is analyzed through the use of a case study.

  12. Constraint-Based Simulation for Non-Rigid Real-Time Registration

    OpenAIRE

    Courtecuisse, Hadrien; Peterlik, Igor; Trivisonne, Raffaella; Duriez, Christian; Cotin, Stéphane

    2014-01-01

    International audience; In this paper we propose a method to address the problem of non-rigid registration in real-time. We use Lagrange multipliers and soft sliding constraints to combine data acquired from dynamic image sequence and a biomechanical model of the structure of interest. The biomechanical model plays a role of regulariza-tion to improve the robustness and the flexibility of the registration. We apply our method to a pre-operative 3D CT scan of a porcine liver that is registered...

  13. A conservative quaternion-based time integration algorithm for rigid body rotations with implicit constraints

    DEFF Research Database (Denmark)

    Nielsen, Martin Bjerre; Krenk, Steen

    2012-01-01

    A conservative time integration algorithm for rigid body rotations is presented in a purely algebraic form in terms of the four quaternions components and the four conjugate momentum variables via Hamilton’s equations. The introduction of an extended mass matrix leads to a symmetric set of eight...... state-space equations where constraints are embedded without explicit use of Lagrange multipliers. The algorithm is developed by forming a finite increment of the Hamiltonian, which defines the proper selection of increments and mean values that leads to conservation of energy and momentum. The accuracy...

  14. Morphology, topography, and hardness of diffusion bonded sialon to AISI 420 at different bonding time

    Science.gov (United States)

    Ibrahim, Nor Nurulhuda Md.; Hussain, Patthi; Awang, Mokhtar

    2015-07-01

    Sialon and AISI 420 martensitic stainless steel were diffusion bonded in order to study the effect of bonding time on reaction layer's growth. Joining of these materials was conducted at 1200°C under a uniaxial pressure of 17 MPa in a vacuum ranging from 5.0 to 8.0×10-6 Torr with bonding time varied for 0.5, 2, and 3 h. Thicker reaction layer was formed in longer bonded sample since the elements from sialon could diffuse further into the steel. Sialon retained its microstructure but it was affected at the initial contact with the steel to form the new interface layer. Diffusion layer grew toward the steel and it was segregated with the parent steel as a result of the difference in properties between these regions. The segregation formed a stream-like structure and its depth decreased when the bonding time was increased. The microstructure of the steel transformed into large grain size with precipitates. Prolonging the bonding time produced more precipitates in the steel and reduced the steel thickness as well. Interdiffusions of elements occurred between the joined materials and the concentrations were decreasing toward the steel and vice versa. Silicon easily diffused into the steel because it possessed lower ionization potential compared to nitrogen. Formation of silicide and other compounds such as carbides were detected in the interface layer and steel grain boundary, respectively. These compounds were harmful due to silicide brittleness and precipitation of carbides in the grain boundary might cause intergranular corrosion cracking. Sialon retained its hardness but it dropped very low at the interface layer. The absence of crack at the joint in all samples could be contributed from the ductility characteristic of the reaction layer which compensated the residual stress that was formed upon the cooling process.

  15. Time-lapse electrical surveys to locate infiltration zones in weathered hard rock tropical areas

    Science.gov (United States)

    Wubda, M.; Descloitres, M.; Yalo, N.; Ribolzi, O.; Vouillamoz, J. M.; Boukari, M.; Hector, B.; Séguis, L.

    2017-07-01

    In West Africa, infiltration and groundwater recharge processes in hard rock areas are depending on climatic, surface and subsurface conditions, and are poorly documented. Part of the reason is that identification, location and monitoring of these processes is still a challenge. Here, we explore the potential for time-lapse electrical surveys to bring additional information on these processes for two different climate situations: a semi-arid Sahelian site (north of Burkina and a humid Sudanian site (north of Benin), respectively focusing on indirect (localized) and direct (diffuse) recharge processes. The methodology is based on surveys in dry season and rainy season on typical pond or gully using Electrical Resistivity Tomography (ERT) and frequency electromagnetic (FEM) apparent conductivity mapping. The results show that in the Sahelian zone an indirect recharge occurs as expected, but infiltration doesn't takes place at the center of the pond to the aquifer, but occurs laterally in the banks. In Sudanian zone, the ERT survey shows a direct recharge process as expected, but also a complicated behavior of groundwater dilution, as well as the role of hardpans for fast infiltration. These processes are ascertained by groundwater monitoring in adjacent observing wells. At last, FEM time lapse mapping is found to be difficult to quantitatively interpreted due to the non-uniqueness of the model, clearly evidenced comparing FEM result to auger holes monitoring. Finally, we found that time-lapse ERT can be an efficient way to track infiltration processes across ponds and gullies in both climatic conditions, the Sahelian setting providing results easier to interpret, due to significant resistivity contrasts between dry and rain seasons. Both methods can be used for efficient implementation of punctual sensors for complementary studies. However, FEM time-lapse mapping remains difficult to practice without external information that renders this method less attractive for

  16. arXiv Superradiance in rotating stars and pulsar-timing constraints on dark photons

    CERN Document Server

    Cardoso, Vitor; Yu, Tien-Tien

    2017-06-30

    In the presence of massive bosonic degrees of freedom, rotational superradiance can trigger an instability that spins down black holes. This leads to peculiar gravitational-wave signatures and distribution in the spin-mass plane, which in turn can impose stringent constraints on ultralight fields. Here, we demonstrate that there is an analogous spindown effect for conducting stars. We show that rotating stars amplify low-frequency electromagnetic waves, and that this effect is largest when the time scale for conduction within the star is of the order of a light crossing time. This has interesting consequences for dark photons, as massive dark photons would cause stars to spin down due to superradiant instabilities. The time scale of the spindown depends on the mass of the dark photon, and on the rotation rate, compactness, and conductivity of the star. Existing measurements of the spindown rate of pulsars place direct constraints on models of dark sectors. Our analysis suggests that dark photons of mass mV∼...

  17. Stack Memory Implementation and Analysis of Timing Constraint, Power and Memory using FPGA

    DEFF Research Database (Denmark)

    Pandey, Nisha; Pandey, Bishwajeet; Thind, Vandana

    2017-01-01

    Abstract— in this work of analysis, stack memory algorithm is implemented on a number of FPGA platforms like virtex4, virtex5, virtex6, virtex6 low power and virtex7 low voltage and very detailed observations/investigations were made about timing constraint, memory and power dissipation. The main...... real-time output, so that source used to realize the project is not wasted and get an energy efficient design. However, Stack memory is an approach in which information is entered and deleted from the stack memory segment in the pattern of last in first out mechanism. There are several ways...... of implementation of stack memory algorithm but virtex4 and virtex7 low voltage were considered to be the most efficient platforms for its operation. The developed system is energy efficient as the algorim ensures less memory utilization, less power consumption and short time for signal travel....

  18. Location-Dependent Query Processing Under Soft Real-Time Constraints

    Directory of Open Access Journals (Sweden)

    Zoubir Mammeri

    2009-01-01

    Full Text Available In recent years, mobile devices and applications achieved an increasing development. In database field, this development required methods to consider new query types like location-dependent queries (i.e. the query results depend on the query issuer location. Although several researches addressed problems related to location-dependent query processing, a few works considered timing requirements that may be associated with queries (i.e., the query results must be delivered to mobile clients on time. The main objective of this paper is to propose a solution for location-dependent query processing under soft real-time constraints. Hence, we propose methods to take into account client location-dependency and to maximize the percentage of queries respecting their deadlines. We validate our proposal by implementing a prototype based on Oracle DBMS. Performance evaluation results show that the proposed solution optimizes the percentage of queries meeting their deadlines and the communication cost.

  19. Effect of exercise-induced muscle damage on muscle hardness evaluated by ultrasound real-time tissue elastography.

    Science.gov (United States)

    Yanagisawa, Osamu; Sakuma, Jun; Kawakami, Yasuo; Suzuki, Katsuhiko; Fukubayashi, Toru

    2015-01-01

    To assess the effect of exercise-induced muscle damage on muscle hardness and evaluate the relationship between muscle hardness and muscle damage indicators. Seven men (mean 25.3 years; 172.7 cm; 66.8 kg) performed the single-leg ankle plantar flexion exercise involving both concentric and eccentric contractions (10 sets of 40 repetitions). The hardness of the medial gastrocnemius (MG) was evaluated using ultrasound real-time tissue elastography before, from day 1 to 4, and day 7 after exercise. The strain ratio between the MG and a reference material was calculated. Simultaneously, we evaluated the magnetic resonance T2 value (an index of edema) of the triceps surae, the ankle dorsiflexion range of motion (ROM), and calf muscle soreness. Serum creatine kinase activity was assessed before, 2 and 4 h, and from day 1 to 4 after exercise. The MG showed lower strain ratio, indicating increased muscle hardness, on day 4 post-exercise (P muscle soreness among the post-exercise time points was similar. The decreased strain ratio did not correlate with the increased T2, the decreased joint ROM or muscle soreness. Muscle hardness increased after strenuous resistance exercise, but the change was not related with muscle edema, decreased joint ROM, or muscle soreness resulting from muscle damage.

  20. Seasonal time constraints reduce genetic variation in life-history traits along a latitudinal gradient.

    Science.gov (United States)

    Sniegula, Szymon; Golab, Maria J; Drobniak, Szymon M; Johansson, Frank

    2016-01-01

    Time constraints cause strong selection on life-history traits, because populations need to complete their life cycles within a shorter time. We therefore expect lower genetic variation in these traits in high- than in low-latitude populations, since the former are more time-constrained. The aim was to estimate life-history traits and their genetic variation in an obligately univoltine damselfly along a latitudinal gradient of 2730 km. Populations were grown in the laboratory at temperatures and photoperiods simulating those at their place of origin. In a complementary experiment, individuals from the same families were grown in constant temperature and photoperiod that mimicked average conditions across the latitude. Development time and size was faster and smaller, respectively, and growth rate was higher at northern latitudes. Additive genetic variance was very low for life-history traits, and estimates for egg development time and larval growth rate showed significant decreases towards northern latitudes. The expression of genetic effects in life-history traits differed considerably when individuals were grown in constant rather than simulated and naturally variable conditions. Our results support strong selection by time constraints. They also highlight the importance of growing organisms in their native environment for correct estimates of genetic variance at their place of origin. Our results also suggest that the evolutionary potential of life-history traits is very low at northern compared to southern latitudes, but that changes in climate could alter this pattern. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  1. Allocation of Study Time in Chinese Junior School Students: Habitual Responding, Item Difficulty, and Time Constraints

    Directory of Open Access Journals (Sweden)

    Fuyun eWang

    2016-05-01

    Full Text Available The present study investigated factors influencing Chinese junior school students’ study time allocation and the age difference in the effect of habitual responding. Participants were 240 junior school students (120 girls, 120 boys; aged 13–15 years with half taking part in experiment 1 and half in experiment 2, and 240 young adults aged 18-23 years, (120 women and 120 men, involved in experiment 3a and 3b, all native Chinese speakers. In Experiments 1 and 3a, Chinese word pairs (e.g., moon–star were presented on the screen with three items in one array. In each trial, the items were arranged from left to right, either easy, moderate, then difficult, or the reverse. Participants had either 5 s or no time limits to study the word pairs. In Experiment 2&3b, word pairs were ordered in a column with the easiest items either at the top or bottom position. Results showed interactions among item difficulty, item order, and time limitation in terms of effects on study time allocation of junior school students. Participants tended to learn the items in order (from left to right and from top to bottom, but the effect of item difficulty was greater than that of item order on item selection. Results indicated that agenda and habitual responding have a combined effect on study time allocation and that the contribution of agenda is greater than that of habitual responding. The effect of habitual responding on the self-paced study and recall performance of junior school students is greater than its effect on young adults, and the study time allocation of junior school students is more likely to be affected by external conditions.

  2. Allocation of Study Time in Chinese Junior School Students: Habitual Responding, Item Difficulty, and Time Constraints.

    Science.gov (United States)

    Wang, Fuyun; Qin, Qiwen; Jiang, Yanju

    2016-01-01

    The present study investigated factors influencing Chinese junior school students' study time allocation and the age difference in the effect of habitual responding. Participants were 240 junior school students (120 girls, 120 boys; aged 13-15 years) with half taking part in Experiment 1 and half in Experiment 2, and 240 young adults aged 18-23 years, (120 women and 120 men,) involved in Experiments 3a and 3b, all native Chinese speakers. In Experiments 1 and 3a, Chinese word pairs (e.g., moon-star) were presented on the screen with three items in one array. In each trial, the items were arranged from left to right, either easy, moderate, then difficult, or the reverse. Participants had either 5 s or no time limits to study the word pairs. In Experiments 2 and 3b, word pairs were ordered in a column with the easiest items either at the top or bottom position. Results showed interactions among item difficulty, item order, and time limitation in terms of effects on study time allocation of junior school students. Participants tended to learn the items in order (from left to right and from top to bottom), but the effect of item difficulty was greater than that of item order on item selection. Results indicated that agenda and habitual responding have a combined effect on study time allocation and that the contribution of agenda is greater than that of habitual responding. The effect of habitual responding on the self-paced study and recall performance of junior school students is greater than its effect on young adults, and the study time allocation of junior school students is more likely to be affected by external conditions.

  3. Selecting local constraint for alignment of batch process data with dynamic time warping

    DEFF Research Database (Denmark)

    Spooner, Max Peter; Kold, David; Kulahci, Murat

    2017-01-01

    and variable synchronisation obtained. A local constraint scheme is extended to include constraints not previously considered, and a novel method for selecting the optimal local constraint with respect to the two criteria is proposed. For illustration, the method is applied to real data from an industrial...

  4. Memory State Feedback RMPC for Multiple Time-Delayed Uncertain Linear Systems with Input Constraints

    Directory of Open Access Journals (Sweden)

    Wei-Wei Qin

    2014-01-01

    Full Text Available This paper focuses on the problem of asymptotic stabilization for a class of discrete-time multiple time-delayed uncertain linear systems with input constraints. Then, based on the predictive control principle of receding horizon optimization, a delayed state dependent quadratic function is considered for incorporating MPC problem formulation. By developing a memory state feedback controller, the information of the delayed plant states can be taken into full consideration. The MPC problem is formulated to minimize the upper bound of infinite horizon cost that satisfies the sufficient conditions. Then, based on the Lyapunov-Krasovskii function, a delay-dependent sufficient condition in terms of linear matrix inequality (LMI can be derived to design a robust MPC algorithm. Finally, the digital simulation results prove availability of the proposed method.

  5. Allocation of Study Time in Chinese Junior School Students: Habitual Responding, Item Difficulty, and Time Constraints

    OpenAIRE

    Wang, Fuyun; Qin, Qiwen; Jiang, Yanju

    2016-01-01

    The present study investigated factors influencing Chinese junior school students’ study time allocation and the age difference in the effect of habitual responding. Participants were 240 junior school students (120 girls, 120 boys; aged 13–15 years) with half taking part in Experiment 1 and half in Experiment 2, and 240 young adults aged 18–23 years, (120 women and 120 men,) involved in Experiments 3a and 3b, all native Chinese speakers. In Experiments 1 and 3a, Chinese word pairs (e.g., moo...

  6. Diagnostics of underwater electrical wire explosion through a time- and space-resolved hard x-ray source.

    Science.gov (United States)

    Sheftman, D; Shafer, D; Efimov, S; Gruzinsky, K; Gleizer, S; Krasik, Ya E

    2012-10-01

    A time- and space-resolved hard x-ray source was developed as a diagnostic tool for imaging underwater exploding wires. A ~4 ns width pulse of hard x-rays with energies of up to 100 keV was obtained from the discharge in a vacuum diode consisting of point-shaped tungsten electrodes. To improve contrast and image quality, an external pulsed magnetic field produced by Helmholtz coils was used. High resolution x-ray images of an underwater exploding wire were obtained using a sensitive x-ray CCD detector, and were compared to optical fast framing images. Future developments and application of this diagnostic technique are discussed.

  7. Stability of Switched Server Systems with Constraints on Service-Time and Capacity of Buffers

    Directory of Open Access Journals (Sweden)

    Li Wang

    2015-01-01

    Full Text Available The execution of emptying policy ensures the convergence of any solution to the system to a unique periodic orbit, which does not impose constraints on service-time and capacity of buffers. Motivated by these problems, in this paper, the service-time-limited policy is first proposed based on the information resulted from the periodic orbit under emptying policy, which imposes lower and upper bounds on emptying time for the queue in each buffer, by introducing lower-limit and upper-limit service-time factors. Furthermore, the execution of service-time-limited policy in the case of finite buffer capacity is considered. Moreover, the notion of feasibility of states under service-time-limited policy is introduced and then the checking condition for feasibility of states is given; that is, the solution does not exceed the buffer capacity within the first cycle of the server. At last, a sufficient condition for determining upper-limit service-time factors ensuring that the given state is feasible is given.

  8. Including birefringence into time evolution of CMB: current and future constraints

    Energy Technology Data Exchange (ETDEWEB)

    Gubitosi, G.; Pagano, L. [Physics Department and INFN, Università di Roma ' ' La Sapienza' ' , Ple Aldo Moro 2, 00185, Rome (Italy); Martinelli, M., E-mail: g.gubitosi@imperial.ac.uk, E-mail: martinelli@thphys.uni-heidelberg.de, E-mail: luca.pagano@roma1.infn.it [SISSA, Via Bonomea 265, Trieste, 34136 (Italy)

    2014-12-01

    We introduce birefringence effects within the propagation history of CMB, considering the two cases of a constant effect and of an effect that increases linearly in time, as the rotation of polarization induced by birefringence accumulates during photon propagation. Both cases result into a mixing of E and B modes before lensing effects take place, thus leading to the fact that lensing is acting on spectra that are already mixed because of birefringence. Moreover, if the polarization rotation angle increases during propagation, birefringence affects more the large scales that the small scales. We put constraints on the two cases using data from WMAP 9yr and BICEP 2013 and compare these results with the constraints obtained when the usual procedure of rotating the final power spectra is adopted, finding that this dataset combination is unable to distinguish between effects, but it nevertheless hints for a non vanishing value of the polarization rotation angle. We also forecast the sensitivity that will be obtained using data from Planck and PolarBear, highlighting how this combination is capable to rule out a vanishing birefringence angle, but still unable to distinguish the different scenarios. Nevertheless, we find that the combination of Planck and PolarBear is sensitive enough to highlight the existence of degeneracies between birefringence rotation and gravitational lensing of CMB photons, possibly leading to false detection of non standard lensing effects if birefringence is neglected.

  9. Effect of sintering time and temperature on properties of high pressure assisted WC/Co hard metal composite

    Energy Technology Data Exchange (ETDEWEB)

    Karimi, M.M.; Gomes, U.U.; Oliveira, M.P.; Filgueira, M. [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil)

    2016-07-01

    Full text: WC/Co is widely used as cutting tools, because has a unique combination of high strength, hardness, toughness, and moderate stiffness, especially with fine grained WC and finely distributed cobalt. WC/Co powder mixture sinters by different methods such as vacuum sintering, microwave sintering and SPS. High pressure high temperature (HPHT) sintering is a proposed method that can results in better distribution of cobalt and avoid undesirable phases by using high pressure, high temperature and very low sintering time. In this study, a powder mixture of WC- 10 wt% Co was sintered by HPHT at 1500 to 1900 deg C under a pressure of 7.7 GPa for 2 and 3 minutes. Microstructural/structural analyses were performed by SEM/EDS and XRD. Hardness was also done to obtain the effect of sintering parameters. It was found that increasing sintering time in HPHT sintering method at a constant temperature can improve properties of WC/Co hard metal. It was also realized that both sintering temperature and time have effect on hardness and density. (author)

  10. The influence of referees' expertise, gender, motivation, and time constraints on decisional bias against women.

    Science.gov (United States)

    Souchon, Nicolas; Livingstone, Andrew G; Maio, Gregory R

    2013-12-01

    The influence of player gender on referees' decision making was experimentally investigated. In Experiment 1, including 145 male handball referees, we investigated (a) the influence of referees' level of expertise on their decisional biases against women and (b) the referees' gender stereotypes. Results revealed that biases against women were powerful regardless of the referees' level of expertise and that male referees' stereotype toward female players tends to be negative. In Experiment 2, including 115 sport science students, we examined the influence of the participants' gender, motivation to control bias, and time constraints on gender bias. Results indicated that participants' gender had no impact on gender bias and that participants were able to reduce this bias in conditions in which they were motivated to control the bias.

  11. Systematic Hybrid Network Scheduling for Multiple Traffic Classes with Host Timing and Phase Constraints

    Science.gov (United States)

    Varadarajan, Srivatsan (Inventor); Hall, Brendan (Inventor); Smithgall, William Todd (Inventor); Bonk, Ted (Inventor); DeLay, Benjamin F. (Inventor)

    2017-01-01

    Systems and methods for systematic hybrid network scheduling for multiple traffic classes with host timing and phase constraints are provided. In certain embodiments, a method of scheduling communications in a network comprises scheduling transmission of virtual links pertaining to a first traffic class on a global schedule to coordinate transmission of the virtual links pertaining to the first traffic class across all transmitting end stations on the global schedule; and scheduling transmission of each virtual link pertaining to a second traffic class on a local schedule of the respective transmitting end station from which each respective virtual link pertaining to the second traffic class is transmitted such that transmission of each virtual link pertaining to the second traffic class is coordinated only at the respective end station from which each respective virtual link pertaining to the second traffic class is transmitted.

  12. Instruction and Service Time Decisions: Itinerant Services to Deaf and Hard-of-Hearing Students

    Science.gov (United States)

    Antia, Shirin D.; Rivera, M. Christina

    2016-01-01

    The purpose of this study was to (a) describe the specific kinds of services provided by itinerant teachers to deaf and hard-of-hearing (DHH) students in general education settings, (b) examine the relationship between student academic performance and instructional support provided by the itinerant teacher, and (c) examine how service provision…

  13. A Time-Dependent Λ and G Cosmological Model Consistent with Cosmological Constraints

    Directory of Open Access Journals (Sweden)

    L. Kantha

    2016-01-01

    Full Text Available The prevailing constant Λ-G cosmological model agrees with observational evidence including the observed red shift, Big Bang Nucleosynthesis (BBN, and the current rate of acceleration. It assumes that matter contributes 27% to the current density of the universe, with the rest (73% coming from dark energy represented by the Einstein cosmological parameter Λ in the governing Friedmann-Robertson-Walker equations, derived from Einstein’s equations of general relativity. However, the principal problem is the extremely small value of the cosmological parameter (~10−52 m2. Moreover, the dark energy density represented by Λ is presumed to have remained unchanged as the universe expanded by 26 orders of magnitude. Attempts to overcome this deficiency often invoke a variable Λ-G model. Cosmic constraints from action principles require that either both G and Λ remain time-invariant or both vary in time. Here, we propose a variable Λ-G cosmological model consistent with the latest red shift data, the current acceleration rate, and BBN, provided the split between matter and dark energy is 18% and 82%. Λ decreases (Λ~τ-2, where τ is the normalized cosmic time and G increases (G~τn with cosmic time. The model results depend only on the chosen value of Λ at present and in the far future and not directly on G.

  14. Transportation Energy Futures Series: Vehicle Technology Deployment Pathways: An Examination of Timing and Investment Constraints

    Energy Technology Data Exchange (ETDEWEB)

    Plotkin, S.; Stephens, T.; McManus, W.

    2013-03-01

    Scenarios of new vehicle technology deployment serve various purposes; some will seek to establish plausibility. This report proposes two reality checks for scenarios: (1) implications of manufacturing constraints on timing of vehicle deployment and (2) investment decisions required to bring new vehicle technologies to market. An estimated timeline of 12 to more than 22 years from initial market introduction to saturation is supported by historical examples and based on the product development process. Researchers also consider the series of investment decisions to develop and build the vehicles and their associated fueling infrastructure. A proposed decision tree analysis structure could be used to systematically examine investors' decisions and the potential outcomes, including consideration of cash flow and return on investment. This method requires data or assumptions about capital cost, variable cost, revenue, timing, and probability of success/failure, and would result in a detailed consideration of the value proposition of large investments and long lead times. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency effort to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

  15. Transportation Energy Futures Series. Vehicle Technology Deployment Pathways. An Examination of Timing and Investment Constraints

    Energy Technology Data Exchange (ETDEWEB)

    Plotkin, Steve [Argonne National Lab. (ANL), Argonne, IL (United States); Stephens, Thomas [Argonne National Lab. (ANL), Argonne, IL (United States); McManus, Walter [Oakland Univ., Rochester, MI (United States)

    2013-03-01

    Scenarios of new vehicle technology deployment serve various purposes; some will seek to establish plausibility. This report proposes two reality checks for scenarios: (1) implications of manufacturing constraints on timing of vehicle deployment and (2) investment decisions required to bring new vehicle technologies to market. An estimated timeline of 12 to more than 22 years from initial market introduction to saturation is supported by historical examples and based on the product development process. Researchers also consider the series of investment decisions to develop and build the vehicles and their associated fueling infrastructure. A proposed decision tree analysis structure could be used to systematically examine investors' decisions and the potential outcomes, including consideration of cash flow and return on investment. This method requires data or assumptions about capital cost, variable cost, revenue, timing, and probability of success/failure, and would result in a detailed consideration of the value proposition of large investments and long lead times. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency effort to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

  16. Time domain localization technique with sparsity constraint for imaging acoustic sources

    Science.gov (United States)

    Padois, Thomas; Doutres, Olivier; Sgard, Franck; Berry, Alain

    2017-09-01

    This paper addresses source localization technique in time domain for broadband acoustic sources. The objective is to accurately and quickly detect the position and amplitude of noise sources in workplaces in order to propose adequate noise control options and prevent workers hearing loss or safety risk. First, the generalized cross correlation associated with a spherical microphone array is used to generate an initial noise source map. Then a linear inverse problem is defined to improve this initial map. Commonly, the linear inverse problem is solved with an l2 -regularization. In this study, two sparsity constraints are used to solve the inverse problem, the orthogonal matching pursuit and the truncated Newton interior-point method. Synthetic data are used to highlight the performances of the technique. High resolution imaging is achieved for various acoustic sources configurations. Moreover, the amplitudes of the acoustic sources are correctly estimated. A comparison of computation times shows that the technique is compatible with quasi real-time generation of noise source maps. Finally, the technique is tested with real data.

  17. Optimal Decision for Fashion Supply Chains with Service Level Constraint and Controllable Lead Time

    Directory of Open Access Journals (Sweden)

    Guo Li

    2015-01-01

    Full Text Available We study a two-echelon supply chain inventory model with controllable lead time and service level constraint in fashion supply chains, in which we assume that the unit cost of compressing lead time follows exponential distribution. Under these conditions we investigate the optimal ordering quantity and production quantity in the fashion supply chain by minimizing the joint total cost. Simultaneously, we work out the boundaries of ordering quantity and production quantity, which simplify the computation. Furthermore, numerical examples are presented to test the feasibility of the model. The results show that assuming the unit cost of compressing lead time in accordance with exponential distribution is realistic. It also notices that the optimal order and production decision for fashion supply chains are constrained obviously by the service level and safety factors. What is more, the holding cost rate of both the service level and safety factors has a certain influence on it. And by further analyzing on some references in the last part, we have done some extensions and found some interesting results.

  18. Elevated hardness of peripheral gland on real-time elastography is an independent marker for high-risk prostate cancers.

    Science.gov (United States)

    Zhang, Qi; Yao, Jing; Cai, Yehua; Zhang, Limin; Wu, Yishuo; Xiong, Jingyu; Shi, Jun; Wang, Yuanyuan; Wang, Yi

    2017-12-01

    To examine the role of quantitative real-time elastography (RTE) features on differentiation between high-risk prostate cancer (PCA) and non-high-risk prostatic diseases in the initial transperineal biopsy setting. We retrospectively included 103 patients with suspicious PCA who underwent both RTE and initial transperineal prostate biopsy. Patients were grouped into high-risk and non-high-risk categories according to the D'Amico's risk stratification. With computer assistance based on MATLAB programming, three features were extracted from RTE, i.e., the median hardness within peripheral gland (PG) (H med ), the ratio of the median hardness within PG to that outside PG (H ratio ), and the ratio of the hard area within PG to the total PG area (H ar ). A multiple regression model incorporating an RTE feature, age, transrectal ultrasound finding, and prostate volume was used to identify markers for high-risk PCA. Forty-seven patients (45.6%) were diagnosed with PCA and 34 (33.0%) were diagnosed with high-risk PCA. Three RTE features were all statistically higher in high-risk PCA than in non-high-risk diseases (p hardness of PG identified high-risk PCA and served as an independent marker of high-risk PCA. As a non-invasive imaging modality, the RTE could be potentially used in routine clinical practice for the detection of high-risk PCA to decrease unnecessary biopsies and reduce overtreatment.

  19. Modeling of dough mixing profile under thermal and non thermal constraint for evalution of breadmaking quality of Hard Spring Wheat flour

    Science.gov (United States)

    This research was initiated to investigate the association between flour breadmaking traits and mixing characteristics and empirical dough rheological property under thermal stress. Flour samples from 30 hard spring wheat were analyzed by a mixolab standard procedure at optimum water absorptions. Mi...

  20. Hard X-ray spectral and timing properties of IGR J17454-2919 consistent with a black hole in the hard state

    DEFF Research Database (Denmark)

    Tendulkar, Shriharsh P.; Bachetti, Matteo; Tomsick, J.

    2014-01-01

    frequencies. The Lorentzian has a width of 2 Hz and a fractional rms of 25+/-3%. The hard power-law index, the high energy of the cutoff, and the level of variability all are consistent with properties expected for an accreting black hole in the hard state. While we cannot completely rule out the possibility...... of a low magnetic field neutron star, a black hole is more likely....

  1. Proximal and Time-Varying Effects of Cigarette, Alcohol, Marijuana and other Hard Drug Use on Adolescent Dating Aggression

    OpenAIRE

    Reyes, H. Luz McNaughton; Vangie A Foshee; Bauer, Daniel J.; Ennett, Susan T.

    2014-01-01

    Although numerous studies have established a link between substance use and adult partner violence, little research has examined the relationship during adolescence and most extant research has not examined multiple substance use types. The current study used hierarchical growth modeling to simultaneously examine proximal (between-person) and time-varying (within-person) relations between cigarette, alcohol, marijuana and hard drug use and physical dating aggression across grades 8 through 12...

  2. Effect of immersion time of restorative glass ionomer cements and immersion duration in calcium chloride solution on surface hardness.

    Science.gov (United States)

    Shiozawa, Maho; Takahashi, Hidekazu; Iwasaki, Naohiko; Wada, Takahiro; Uo, Motohiro

    2014-12-01

    The objective of this study was to evaluate the effect of immersion time of restorative glass ionomer cements (GICs) and immersion duration in calcium chloride (CaCl2) solution on the surface hardness. Two high-viscosity GICs, Fuji IX GP and GlasIonomer FX-II, were selected. Forty-eight specimens were randomly divided into two groups. Sixty minutes after being mixed, half of them were immersed in a 42.7wt% CaCl2 solution for 10, 30, or 60min (Group 1); the remaining specimens were immersed after an additional 1-week of storage (Group 2). The surface hardness of the specimens was measured and analyzed with two-way ANOVA and the Tukey HSD test (α=0.05). The surface compositions were examined using energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The surface hardness of Group 1 significantly increased as the immersion duration in CaCl2 increased; that of Group 2 significantly increased only after 60-minute CaCl2 immersion. After CaCl2 immersion, the amounts of Ca increased as the immersion duration increased. The surface hardness after CaCl2 immersion significantly correlated with the amount of Ca in Group 1, but not in Group 2. The binding energy of the Ca2p peak was similar to that of calcium polyalkenoate. These findings indicated that the Ca ions from the CaCl2 solution created chemical bonds with the carboxylic acid groups in the cement matrix. Immersion of GICs in CaCl2 solution at the early stage of setting was considered to enhance the formation of the polyacid salt matrix; as a result, the surface hardness increased. Copyright © 2014. Published by Elsevier Ltd.

  3. The effects of Exposure Times and Light Curing Sources on Surface Micro-Hardness of a Resin Modified Glass Ionomer

    Directory of Open Access Journals (Sweden)

    Iman Parisay

    2014-06-01

    Full Text Available Introduction: The aim of this study was to evaluate the influenceof different light curing systems and curing times on the micro-hardness of aresin modified glass ionomer. Methods: Forty two samples of ResinModified Glass Ionomer (RMGI were prepared using stainless steel cylindrical mold(8 × 2 mm and randomly divided into six groups of seven. Three groups werecured with a Quartz Tungsten Halogen (QTH light cure unit and the other threegroups were polymerized with LED unit for 20, 30 and 40 seconds. All sampleswere stored in distilled water for 24 hours. The micro-hardness was measured onthe top and bottom surfaces of the samples by Vickers hardness tester. Datawere analyzed by two–way ANOVA and Tukey’s post-hoc tests. Results: Two-wayANOVA showed that QTH light-cure unit had higher percentage in depth of curethan LED light-curing unit in both surfaces; whereas, the application time hasno significant effect on it. There was no interaction between two variables. Inboth light-curing groups, the values of top and bottom surfaces micro-hardnesswere increased as the application time increased, but there was not anystatistically significant difference among these groups except for 40-second groupof LED light-curing unit which was significantly higher than 20-second and30-second groups (P

  4. Evaluate the Effect of Commercially Available Denture Cleansers on Surface Hardness and Roughness of Denture Liners at Various Time Intervals

    Science.gov (United States)

    Mohammed, Hilal S.; Singh, Sumeet; Hari, Prasad A.; Amarnath, G. S.; Kundapur, Vinaya; Pasha, Naveed; Anand, M.

    2016-01-01

    Background and objective: Chemical cleansing by denture cleansers is first choice for denture plaque control. The most common problems while using denture cleansers are hardening, porosity, odor sorption, water sorption, solubility, and colour change, bacterial and fungal growth. Chemical cleansing procedures have been found to have an effect on the physical and mechanical properties of denture liners. Thus, this study was conducted to evaluate the effect of commercially available denture cleansers on surface hardness and roughness of acrylic and silicon based denture liners at various time interval. Method: Two autopolymerising denture liners Kooliner (acrylic) and GC reline soft (silicon) were tested with two commercially available denture cleansers, polident and efferdent plus. Total of 120 specimens were prepared and all the specimens were divided into six groups based on the relining materials and denture cleansers used. Surface hardness and surface roughness was tested using Shore A durometer and profilometer respectively at the end of day 1, day 7, day 30 and day 90. All the specimens were stored in artificial saliva throughout the study. Cleanser solution was prepared daily by adding Polident and Efferdent plus denture cleanser tablet into 250ml of enough very warm (not hot) water. Acrylic and silicon liner groups were cleansed in a solution of denture cleanser and water for 15 minutes daily, rinsed with water and stored in artificial saliva at room temperature. The data was analyzed with one way ANOVA and independent t-test. Result: The acrylic soft lining showed gradual hardening and increase in surface roughness after immersion in denture cleanser and also with time. Acrylic liner material showed maximum hardness and roughness with Polident followed by Efferdent plus and water (control group). Silicone lining material showed a slight difference in hardness and roughness between the test group and control group. There was a slight increase in hardness in

  5. Effect of denture cleansers on surface hardness of resilient denture liners at various time intervals- an in vitro study.

    Science.gov (United States)

    Pahuja, Rasleen Kaur; Garg, Sandeep; Bansal, Sanjay; Dang, Rajat Harvinder

    2013-08-01

    This study was aimed to determine the effect of two chemically distinct denture cleansers and water on the surface hardness of acrylic and silicone based soft denture liners at various time intervals. Two commonly used commercial resilient liner material were selected based on their chemical composition (silicone- and acrylic-based soft liners) for this investigation. 120 cylindrical specimens were made of 15 mm × 10 mm dimensions (according to ASTM: D-2240-64T) in a custom made metal mold. All specimens were stored in artificial saliva throughout the study. Forty specimens were cleansed daily in 0.5% sodium hypochlorite solution; forty were cleansed in sodium perborate and remaining forty specimens were daily rinsed in water. Testing was done at 1 week, 1 month, 3 months and 6 months for surface hardness using a Shore A Durometer. A mean of 3 reading for each sample was subjected to one-way ANOVA, Post Hoc test and pair-t test for statistical analysis. P values of less than 0.05 were taken as statistically significant. Surface hardness of all the samples was significantly higher after a period of 6 months irrespective of the cleansing treatment. Minor changes were observed between control, sodium hypochlorite and sodium perborate groups with time. Greater change was observed in surface hardness of acrylic-based soft denture liners as compared to silicone-based soft liners for all groups, as time progressed. Silicone-based soft denture liners performed significantly better in all cleansing treatments than acrylic-based soft denture liners.

  6. Resolving time and space constraints during neural crest formation and delamination.

    Science.gov (United States)

    Duband, Jean-Loup; Dady, Alwyn; Fleury, Vincent

    2015-01-01

    A striking feature of neural crest development in vertebrates is that all the specification, delamination, migration, and differentiation steps occur consecutively in distinct areas of the embryo and at different timings of development. The significance and consequences of this partition into clearly separated events are not fully understood yet, but it ought to be related to the necessity of controlling precisely and independently each step, given the wide array of cell types and tissues derived from the neural crest and the long duration of their development spanning almost the entire embryonic life. In this chapter, using the examples of early neural crest induction and delamination, we discuss how time and space constraints influence their development and describe the molecular and cellular responses that are employed by cells to adapt. In the first example, we analyze how cell sorting and cell movements cooperate to allow nascent neural crest cells, which are initially mingled with other neurectodermal progenitors after induction, to segregate from the neural tube and ectoderm populations and settle at the apex of the neural tube prior to migration. In the second example, we examine how cadherins drive the entire process of neural crest segregation from the rest of the neurectoderm by their dual role in mediating first cell sorting and cohesion during specification and later in promoting their delamination. In the third example, we describe how the expression and activity of the transcription factors known to drive epithelium-to-mesenchyme transition (EMT) are regulated timely and spatially by the cellular machinery so that they can alternatively and successively regulate neural crest specification and delamination. In the last example, we briefly tackle the problem of how factors triggering EMT may elicit different cell responses in neural tube and neural crest progenitors. © 2015 Elsevier Inc. All rights reserved.

  7. Timing Constraints on Remote Sensing of Wildland Fire Burned Area in the Southeastern US

    Directory of Open Access Journals (Sweden)

    Kevin Robertson

    2011-08-01

    Full Text Available Remote sensing using Landsat Thematic Mapper (TM satellite imagery is increasingly used for mapping wildland fire burned area and burn severity, owing to its frequency of collection, relatively high resolution, and availability free of charge. However, rapid response of vegetation following fire and frequent cloud cover pose challenges to this approach in the southeastern US. We assessed these timing constraints by using a series of Landsat TM images to determine how rapidly the remotely sensed burn scar signature fades following prescribed burns in wet flatwoods and depression swamp community types in the Apalachicola National Forest, Florida, USA during 2006. We used both the Normalized Burn Ratio (NBR of reflectance bands sensitive to vegetation and exposed soil cover, as well as the change in NBR from before to after fire (dNBR, to estimate burned area. We also determined the average and maximum amount of time following fire required to obtain a cloud-free image for burns in each month of the year, as well as the predicted effect of this time lag on percent accuracy of burn scar estimates. Using both NBR and dNBR, the detectable area decreased linearly 9% per month on average over the first four months following fire. Our findings suggest that the NBR and dNBR methods for monitoring burned area in common southeastern US vegetation community types are limited to an average of 78–90% accuracy among months of the year, with individual burns having values as low as 38%, if restricted to use of Landsat 5 TM imagery. However, the majority of burns can still be mapped at accuracies similar to those in other regions of the US, and access to additional sources of satellite imagery would improve overall accuracy.

  8. Timing constraints on remote sensing of wildland fire burned area in the southeastern US

    Science.gov (United States)

    Picotte, Joshua J.; Robertson, Kevin

    2011-01-01

    Remote sensing using Landsat Thematic Mapper (TM) satellite imagery is increasingly used for mapping wildland fire burned area and burn severity, owing to its frequency of collection, relatively high resolution, and availability free of charge. However, rapid response of vegetation following fire and frequent cloud cover pose challenges to this approach in the southeastern US. We assessed these timing constraints by using a series of Landsat TM images to determine how rapidly the remotely sensed burn scar signature fades following prescribed burns in wet flatwoods and depression swamp community types in the Apalachicola National Forest, Florida, USA during 2006. We used both the Normalized Burn Ratio (NBR) of reflectance bands sensitive to vegetation and exposed soil cover, as well as the change in NBR from before to after fire (dNBR), to estimate burned area. We also determined the average and maximum amount of time following fire required to obtain a cloud-free image for burns in each month of the year, as well as the predicted effect of this time lag on percent accuracy of burn scar estimates. Using both NBR and dNBR, the detectable area decreased linearly 9% per month on average over the first four months following fire. Our findings suggest that the NBR and dNBR methods for monitoring burned area in common southeastern US vegetation community types are limited to an average of 78–90% accuracy among months of the year, with individual burns having values as low as 38%, if restricted to use of Landsat 5 TM imagery. However, the majority of burns can still be mapped at accuracies similar to those in other regions of the US, and access to additional sources of satellite imagery would improve overall accuracy.

  9. Influence of ageing time on hardness, microstructure and wear behaviour of AISI2507 super duplex stainless steel

    Science.gov (United States)

    Davanageri, Mahesh; Narendranath, S.; Kadoli, Ravikiran

    2017-08-01

    The effect of ageing time on hardness, microstructure and wear behaviour of super duplex stainless AISI 2507 is examined. The material was solution treated at 1050 °C and water quenched, further the ageing has been carried out at 850 °C for 30 min, 60 min and 90 min. The chromium (Cr) and molybdenum (Mo) enriched intermetallic sigma phase (σ) were found to precipitate at the ferrite/austenite interface and within the ferrite region. The concentration of intermetallic sigma phase (σ), which was quantified by a combination of scanning electron microscopy and image analysis, increases with increasing ageing time, leading to significant increase in the hardness. The x-ray diffraction (XRD) and energy dispersive x-ray (EDX) was employed to investigate the element distribution and phase identification. Wear characterstics of the aged super duplex stainless steel were measured by varying normal loads, sliding speeds, sliding distance and compared with solution treated (as-cast) specimens. Scanning electron microscopy was used to assist in analysis of worn out surfaces. The outcomes suggested that the increase in percentage of sigma phase increases hardness and wear resistance in heat-treated specimens compared to solution treated specimens (as-cast).

  10. Some Investigations on Hardness of Investment Casting Process After Advancements in Shell Moulding for Reduction in Cycle Time

    Science.gov (United States)

    Singh, R.; Mahajan, V.

    2014-07-01

    In the present work surface hardness investigations have been made on acrylonitrile butadiene styrene (ABS) pattern based investment castings after advancements in shell moulding for replication of biomedical implants. For the present study, a hip joint, made of ABS material, was fabricated as a master pattern by fused deposition modelling (FDM). After preparation of master pattern, mold was prepared by deposition of primary (1°), secondary (2°) and tertiary (3°) coatings with the addition of nylon fibre (1-2 cm in length of 1.5D). This study outlines the surface hardness mechanism for cast component prepared from ABS master pattern after advancement in shell moulding. The results of study highlight that during shell production, fibre modified shells have a much reduced drain time. Further the results are supported by cooling rate and micro structure analysis of casting.

  11. Effects of boron addition and austempering time on microstructure, hardness and tensile properties of ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Guerra L, F.V. [Instituto de Inv. En Metalurgia y Materiales UMSNH, México (Mexico); Bedolla-Jacuinde, A., E-mail: abedollj@icloud.com [Instituto de Inv. En Metalurgia y Materiales UMSNH, México (Mexico); Mejía, I. [Instituto de Inv. En Metalurgia y Materiales UMSNH, México (Mexico); Facultad de Ingeniería Mecánica UAEH, México (Mexico); Zuno, J. [Facultad de Ingeniería Mecánica UAEH, México (Mexico); Maldonado, C. [Instituto de Inv. En Metalurgia y Materiales UMSNH, México (Mexico)

    2015-11-11

    The present work analyzes the effect of boron addition to an Austempered Ductile Iron, in amounts from zero to 120 ppm. It has been found that boron has a strong effect on the equivalent carbon content, resulting in an increase on the precipitated graphite volume and a decrease in the dissolved carbon content in the matrix. This in turn, increases the ferrite volume fraction in the as-cast conditions from 0.24 in the base alloy to 0.78 for the iron with 120 ppm of boron. Furthermore, a decrease in the nodularity from 100% in the base alloy to 83% with 120 ppm of boron has been observed. During austempering, the transformation to ausferrite was faster and lower volumes of martensite and unstable austenite were detected when boron increased; this promoted lower hardness values, 239 HV for the base iron and 189 HV for the 120 ppm boron alloy. The increase in hardness and strength, typical for the start of bainite formation, were not observed in the boron added irons, but just in the base alloy. Under this basis, it is assumed that at least the addition of 60 ppm of boron extended the optimal processing window. The higher values of strength and ductility were obtained for the alloy with 60 ppm of boron; these results are discussed in terms of the graphitizing effect of boron in these irons and the reduced amount of carbon dissolved in austenite.

  12. Time-reversal constraint limits unidirectional photon emission in slow-light photonic crystals.

    Science.gov (United States)

    Lang, Ben; Beggs, Daryl M; Oulton, Ruth

    2016-08-28

    Photonic crystal waveguides are known to support C-points-point-like polarization singularities with local chirality. Such points can couple with dipole-like emitters to produce highly directional emission, from which spin-photon entanglers can be built. Much is made of the promise of using slow-light modes to enhance this light-matter coupling. Here we explore the transition from travelling to standing waves for two different photonic crystal waveguide designs. We find that time-reversal symmetry and the reciprocal nature of light places constraints on using C-points in the slow-light regime. We observe two distinctly different mechanisms through which this condition is satisfied in the two waveguides. In the waveguide designs, we consider a modest group velocity of vg≈c/10 is found to be the optimum for slow-light coupling to the C-points.This article is part of the themed issue 'Unifying physics and technology in light of Maxwell's equations'. © 2016 The Author(s).

  13. Adjustment to Subtle Time Constraints and Power Law Learning in Rapid Serial Visual Presentation.

    Science.gov (United States)

    Shin, Jacqueline C; Chang, Seah; Cho, Yang Seok

    2015-01-01

    We investigated whether attention could be modulated through the implicit learning of temporal information in a rapid serial visual presentation (RSVP) task. Participants identified two target letters among numeral distractors. The stimulus-onset asynchrony immediately following the first target (SOA1) varied at three levels (70, 98, and 126 ms) randomly between trials or fixed within blocks of trials. Practice over 3 consecutive days resulted in a continuous improvement in the identification rate for both targets and attenuation of the attentional blink (AB), a decrement in target (T2) identification when presented 200-400 ms after another target (T1). Blocked SOA1s led to a faster rate of improvement in RSVP performance and more target order reversals relative to random SOA1s, suggesting that the implicit learning of SOA1 positively affected performance. The results also reveal "power law" learning curves for individual target identification as well as the reduction in the AB decrement. These learning curves reflect the spontaneous emergence of skill through subtle attentional modulations rather than general attentional distribution. Together, the results indicate that implicit temporal learning could improve high level and rapid cognitive processing and highlights the sensitivity and adaptability of the attentional system to subtle constraints in stimulus timing.

  14. Adjustment to subtle time constraints and power law learning in rapid serial visual presentation

    Directory of Open Access Journals (Sweden)

    Jacqueline Chakyung Shin

    2015-11-01

    Full Text Available We investigated whether attention could be modulated through the implicit learning of temporal information in a rapid serial visual presentation (RSVP task. Participants identified two target letters among numeral distractors. The stimulus-onset asynchrony immediately following the first target (SOA1 varied at three levels (70, 98, and 126 ms randomly between trials or fixed within blocks of trials. Practice over three consecutive days resulted in a continuous improvement in the identification rate for both targets and attenuation of the attentional blink (AB, a decrement in target (T2 identification when presented 200-400 ms after another target (T1. Blocked SOA1s led to a faster rate of improvement in RSVP performance and more target order reversals relative to random SOA1s, suggesting that the implicit learning of SOA1 positively affected performance. The results also reveal power law learning curves for individual target identification as well as the reduction in the AB decrement. These learning curves reflect the spontaneous emergence of skill through subtle attentional modulations rather than general attentional distribution. Together, the results indicate that implicit temporal learning could improve high level and rapid cognitive processing and highlights the sensitivity and adaptability of the attentional system to subtle constraints in stimulus timing.

  15. Pipelining Memetic Algorithms, Constraint Satisfaction, and Local Search for Course Timetabling

    Science.gov (United States)

    Conant-Pablos, Santiago E.; Magaña-Lozano, Dulce J.; Terashima-Marín, Hugo

    This paper introduces a hybrid algorithm that combines local search and constraint satisfaction techniques with memetic algorithms for solving Course Timetabling hard problems. These problems require assigning a set of courses to a predetermined finite number of classrooms and periods of time, complying with a complete set of hard constraints while maximizing the consistency with a set of preferences (soft constraints). The algorithm works in a three-stage sequence: first, it creates an initial population of approximations to the solution by partitioning the variables that represent the courses and solving each partition as a constraint-satisfaction problem; second, it reduces the number of remaining hard and soft constraint violations applying a memetic algorithm; and finally, it obtains a complete and fully consistent solution by locally searching around the best memetic solution. The approach produces competitive results, always getting feasible solutions with a reduced number of soft constraints inconsistencies, when compared against the methods running independently.

  16. An investigation of leg and trunk strength and reaction times of hard-style martial arts practitioners.

    Science.gov (United States)

    Donovan, Oliver O; Cheung, Jeanette; Catley, Maria; McGregor, Alison H; Strutton, Paul H

    2006-01-01

    The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT), choice reaction times (CRT) and movement times (MT). Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response to simple and choice auditory cues. Results indicated that the martial arts group generated a greater body-weight adjusted peak torque with both legs at all speeds during isokinetic extension and flexion, and in isometric extension but not flexion. In isokinetic and isometric trunk flexion and extension, martial artists tended to have higher peak torques than controls, but they were not significantly different (p > 0.05). During the SRT and CRT tasks the martial artists were no quicker in lifting their hand off a button in response to the stimulus [reaction time (RT)] but were significantly faster in moving to press another button [movement time (MT)]. In conclusion, the results reveal that training in a martial art increases the strength of both the flexors and extensors of the leg. Furthermore, they have faster movement times to auditory stimuli. These results are consistent with the physical aspects of the martial arts. Key PointsMartial artists undertaking hard-style martial arts have greater strength in their knee flexor and extensor muscles as tested under isokinetic testing. Under isometric testing conditions they have stronger knee extensors only.The trunk musculature is generally higher under both conditions of testing in the martial artists, although not significantly.The total reaction times of the martial artists to an auditory stimulus were significantly faster than the control participants. When analysed further it was revealed that the decrease in reaction time

  17. Non-equilibrium dynamics of hard-core bosons on 1D lattices: short vs large time results

    Science.gov (United States)

    Rigol, Marcos; Muramatsu, Alejandro

    2005-03-01

    Based on an exact treatment we study the non-equilibrium dynamics of hard-core bosons on one-dimensional lattices. Starting from a pure Fock state we find that quasi-long range correlations develop very fast in the system, and they lead to the emergence of quasi-condensates at finite momentum [1]. The exponent observed in the power-law decay of the one-particle density matrix, which develops dynamically, is the same that has been proven to be universal in the equilibrium case [2]. We also study the time evolution of clouds of hard-core bosons when they are released from a harmonic trap. In this case we show that the momentum distribution of the free expanding hard-core bosons approaches to the one of noninteracting fermions [3], in contrast to the known behavior in equilibrium systems. [1] M. Rigol and A. Muramatsu, cond-mat/0403387, to appear in Phys. Rev. Lett. (2004). [2] M. Rigol and A. Muramatsu, Phys. Rev. A 70, 031603(R) (2004); ibid. cond-mat/0409132. [3] M. Rigol and A. Muramatsu, cond-mat/0410683.

  18. Dependent Measure and Time Constraints Modulate the Competition between Conflicting Feature-Based and Rule-Based Generalization Processes

    Science.gov (United States)

    Cobos, Pedro L.; Gutiérrez-Cobo, María J.; Morís, Joaquín; Luque, David

    2017-01-01

    In our study, we tested the hypothesis that feature-based and rule-based generalization involve different types of processes that may affect each other producing different results depending on time constraints and on how generalization is measured. For this purpose, participants in our experiments learned cue-outcome relationships that followed…

  19. Balancing Healthy Meals and Busy Lives: Associations between Work, School, and Family Responsibilities and Perceived Time Constraints among Young Adults

    Science.gov (United States)

    Pelletier, Jennifer E.; Laska, Melissa N.

    2012-01-01

    Objective: To characterize associations between perceived time constraints for healthy eating and work, school, and family responsibilities among young adults. Design: Cross-sectional survey. Setting: A large, Midwestern metropolitan region. Participants: A diverse sample of community college (n = 598) and public university (n = 603) students.…

  20. Proximate effects of temperature versus evolved intrinsic constraints for embryonic development times among temperate and tropical songbirds.

    Science.gov (United States)

    Ton, Riccardo; Martin, Thomas E

    2017-04-18

    The relative importance of intrinsic constraints imposed by evolved physiological trade-offs versus the proximate effects of temperature for interspecific variation in embryonic development time remains unclear. Understanding this distinction is important because slow development due to evolved trade-offs can yield phenotypic benefits, whereas slow development from low temperature can yield costs. We experimentally increased embryonic temperature in free-living tropical and north temperate songbird species to test these alternatives. Warmer temperatures consistently shortened development time without costs to embryo mass or metabolism. However, proximate effects of temperature played an increasingly stronger role than intrinsic constraints for development time among species with colder natural incubation temperatures. Long development times of tropical birds have been thought to primarily reflect evolved physiological trade-offs that facilitate their greater longevity. In contrast, our results indicate a much stronger role of temperature in embryonic development time than currently thought.

  1. Proximate effects of temperature versus evolved intrinsic constraints for embryonic development times among temperate and tropical songbirds

    Science.gov (United States)

    Ton, Riccardo; Martin, Thomas E.

    2017-01-01

    The relative importance of intrinsic constraints imposed by evolved physiological trade-offs versus the proximate effects of temperature for interspecific variation in embryonic development time remains unclear. Understanding this distinction is important because slow development due to evolved trade-offs can yield phenotypic benefits, whereas slow development from low temperature can yield costs. We experimentally increased embryonic temperature in free-living tropical and north temperate songbird species to test these alternatives. Warmer temperatures consistently shortened development time without costs to embryo mass or metabolism. However, proximate effects of temperature played an increasingly stronger role than intrinsic constraints for development time among species with colder natural incubation temperatures. Long development times of tropical birds have been thought to primarily reflect evolved physiological trade-offs that facilitate their greater longevity. In contrast, our results indicate a much stronger role of temperature in embryonic development time than currently thought.

  2. University Course Timetabling using Constraint Programming

    Directory of Open Access Journals (Sweden)

    Hadi Shahmoradi

    2017-03-01

    Full Text Available University course timetabling problem is a challenging and time-consuming task on the overall structure of timetable in every academic environment. The problem deals with many factors such as the number of lessons, classes, teachers, students and working time, and these are influenced by some hard and soft constraints. The aim of solving this problem is to assign courses and classes to teachers and students, so that the restrictions are held. In this paper, a constraint programming method is proposed to satisfy maximum constraints and expectation, in order to address university timetabling problem. For minimizing the penalty of soft constraints, a cost function is introduced and AHP method is used for calculating its coefficients. The proposed model is tested on department of management, University of Isfahan dataset using OPL on the IBM ILOG CPLEX Optimization Studio platform. A statistical analysis has been conducted and shows the performance of the proposed approach in satisfying all hard constraints and also the satisfying degree of the soft constraints is on maximum desirable level. The running time of the model is less than 20 minutes that is significantly better than the non-automated ones.

  3. Real-Time Optimization of a maturing North Sea gas asset with production constraints

    NARCIS (Netherlands)

    Linden, R.J.P. van der; Busking, T.E.

    2013-01-01

    As gas and oil fields mature their operation becomes increasingly more complex, due to complex process dynamics, like slugging, gas coning, water breakthrough, salt or hydrate deposition. Moreover these phenomena also lead to production constraints in the upstream facilities. This complexity asks

  4. Cannibalism and activity rate in larval damselflies increase along a latitudinal gradient as a consequence of time constraints.

    Science.gov (United States)

    Sniegula, Szymon; Golab, Maria J; Johansson, Frank

    2017-07-14

    Predation is ubiquitous in nature. One form of predation is cannibalism, which is affected by many factors such as size structure and resource density. However, cannibalism may also be influenced by abiotic factors such as seasonal time constraints. Since time constraints are greater at high latitudes, cannibalism could be stronger at such latitudes, but we know next to nothing about latitudinal variation in cannibalism. In this study, we examined cannibalism and activity in larvae of the damselfly Lestes sponsa along a latitudinal gradient across Europe. We did this by raising larvae from the egg stage at different temperatures and photoperiods corresponding to different latitudes. We found that the more seasonally time-constrained populations in northern latitudes and individuals subjected to greater seasonal time constraints exhibited a higher level of cannibalism. We also found that activity was higher at north latitude conditions, and thus correlated with cannibalism, suggesting that this behaviour mediates higher levels of cannibalism in time-constrained animals. Our results go counter to the classical latitude-predation pattern which predicts higher predation at lower latitudes, since we found that predation was stronger at higher latitudes. The differences in cannibalism might have implications for population dynamics along the latitudinal gradients, but further experiments are needed to explore this.

  5. A HARDWARE SUPPORTED OPERATING SYSTEM KERNEL FOR EMBEDDED HARD REAL-TIME APPLICATIONS

    NARCIS (Netherlands)

    COLNARIC, M; HALANG, WA; TOL, RM

    1994-01-01

    The concept of the kernel, i.e. the time critical part of a real-time operating system, and its dedicated co-processor, especially tailored for embedded applications, are presented. The co-processor acts as a system controller and operates in conjunction with one or more conventional processors in

  6. Consumption and credit: a model of time-varying liquidity constraints

    OpenAIRE

    Sydney Ludvigson

    1996-01-01

    This paper investigates the role of consumer credit in determining real consumption growth in aggregate, post-war U.S. data. This paper presents evidence that predictable growth in consumer credit is significantly related to consumption growth. The finding is inconsistent with the predictions of (I) the permanent income/life cycle hypothesis, (ii) the "rule of thumb" models where some agents simply consume their current income, and (iii) models of liquidity constraints where individuals face ...

  7. AN INVESTIGATION OF LEG AND TRUNK STRENGTH AND REACTION TIMES OF HARD-STYLE MARTIAL ARTS PRACTITIONERS

    Directory of Open Access Journals (Sweden)

    Oliver O'Donovan

    2006-07-01

    Full Text Available The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT, choice reaction times (CRT and movement times (MT. Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response to simple and choice auditory cues. Results indicated that the martial arts group generated a greater body-weight adjusted peak torque with both legs at all speeds during isokinetic extension and flexion, and in isometric extension but not flexion. In isokinetic and isometric trunk flexion and extension, martial artists tended to have higher peak torques than controls, but they were not significantly different (p > 0.05. During the SRT and CRT tasks the martial artists were no quicker in lifting their hand off a button in response to the stimulus [reaction time (RT] but were significantly faster in moving to press another button [movement time (MT]. In conclusion, the results reveal that training in a martial art increases the strength of both the flexors and extensors of the leg. Furthermore, they have faster movement times to auditory stimuli. These results are consistent with the physical aspects of the martial arts

  8. Adaptive fuzzy dynamic surface control of nonlinear systems with input saturation and time-varying output constraints

    Science.gov (United States)

    Edalati, L.; Khaki Sedigh, A.; Aliyari Shooredeli, M.; Moarefianpour, A.

    2018-02-01

    This paper deals with the design of adaptive fuzzy dynamic surface control for uncertain strict-feedback nonlinear systems with asymmetric time-varying output constraints in the presence of input saturation. To approximate the unknown nonlinear functions and overcome the problem of explosion of complexity, a Fuzzy logic system is combined with the dynamic surface control in the backstepping design technique. To ensure the output constraints satisfaction, an asymmetric time-varying Barrier Lyapunov Function (BLF) is used. Moreover, by applying the minimal learning parameter technique, the number of the online parameters update for each subsystem is reduced to 2. Hence, the semi-globally uniformly ultimately boundedness (SGUUB) of all the closed-loop signals with appropriate tracking error convergence is guaranteed. The effectiveness of the proposed control is demonstrated by two simulation examples.

  9. A Hard Day’s Knights: Movie Time Travel, the Middle Ages, and a New Millenium

    National Research Council Canada - National Science Library

    John Engle

    2012-01-01

    This article addresses the cinematic treatment of the Middle Ages through an analysis of two recent mass-audience American films, Black Knight and Timeline, both of which feature time travel as a leading plot element...

  10. Making a good group decision (low risk) in Singapore under an environment that has time and cost constraints

    OpenAIRE

    Loo, Sok Hiang Candy

    2014-01-01

    Approved for public release; distribution is unlimited Organizations in Singapore operate in a highly competitive and fast-paced work environment that presents decision-making challenges at the individual, group, and organization levels. A key problem is achieving good decision fitness within time and cost constraints. While many decision-making theories and processes address the fundamental decision-making process, there is limited research on improving the group decision-making framework...

  11. Porting the ALMA Correlator Data Processor from hard real-time to plain Linux

    Science.gov (United States)

    Amestica, Rodrigo; Perez, Jesus; Saez, Alejandro

    2016-07-01

    The ALMA correlator back-end consists of a cluster of 16 computing nodes and a master collector/packager node. The mission of the cluster is to process time domain lags into auto-correlations and complex visibilities, integrate them for some configurable amount of time and package them into a workable data product. Computers in the cluster are organized such that individual workloads per node are kept within achievable levels for different observing modes and antennas in the array. Over the course of an observation the master node transmits enough state information to each involved computing node to specify exactly how to process each set of lags received from the correlator. For that distributed mechanism to work, it is necessary to unequivocally identify each individual lag set arriving at each computing node. The original approach was based on a custom hardware interface to each node in the cluster plus a realtime version of the Linux Operating System. A modification recently introduced in the ALMA correlator consists of tagging each lag set with a time stamp before delivering them to the cluster. The time stamp identifies a precise 16- millisecond window during which that specific data set was streamed to the computing cluster. From the time stamp value a node is able to identify a centroid (in absolute time units), base-lines, and correlator mode during that hardware integration. That is, enough information to let the digital signal processing pipeline in each node to process time domain lags into frequency domain auto-correlations per antenna and visibilities per base-line. The scheme also means that a good degree of concurrency can be achieved in each node by having individual CPU cores process individual lag sets at the same time, thus rendering enough processing power to cope with a maximum 1 GiB/sec output from the correlator. The present paper describes how we time stamp lag sets within the correlator hardware, the implications to their on

  12. Simulation of hard X-ray time delays in solar flares

    Directory of Open Access Journals (Sweden)

    Yuri E. Charikov

    2015-06-01

    The spectra were derived from HXR integral over the active region. They were interpreted on the basis of a model of kinetics of accelerated electrons propagating in the flaring loop with the given plasma concentration distribution and magnetic field configuration. The kinetics in question is governed by the processes of Coulomb scattering, reflecting in the converging magnetic field, and with the return current factored in. Solving the time-dependent relativistic Fokker–Planck equation for the given initial conditions allowed to find the time-dependent electron distribution function along the loop. The brightness distribution of the bremsstrahlung of HXR derived from the electron distribution functions was calculated for different quantum energies along the flaring loop and used to plot the time-delays spectra. The calculated data showed that decreasing time-delay spectra were tractable assuming regions of electrons acceleration and injection were separated. The distinction between time-delays spectra from the looptop and footpoints was established. Hence the measurements with high resolving power may produce comprehensive data on the processes of electron transport and acceleration during solar flares.

  13. Enhancing Sequential Time Perception and Storytelling Ability of Deaf and Hard of Hearing Children

    Science.gov (United States)

    Ingber, Sara; Eden, Sigal

    2011-01-01

    A 3-month intervention was conducted to enhance the sequential time perception and storytelling ability of young children with hearing loss. The children were trained to arrange pictorial episodes of temporal scripts and tell the stories they created. Participants (N = 34, aged 4-7 years) were divided into 2 groups based on whether their…

  14. Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources.

    Science.gov (United States)

    Rutherford, Michael E; Chapman, David J; White, Thomas G; Drakopoulos, Michael; Rack, Alexander; Eakins, Daniel E

    2016-05-01

    The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits).

  15. Geomagnetic paleointensity constraints on eruption timing at the Galapagos Spreading Center

    Science.gov (United States)

    Bowles, J. A.; Ab Fatah, A.; Colman, A.; McClinton, J. T.; Sinton, J. M.; White, S. M.; Rubin, K. H.

    2011-12-01

    The intermediate-spreading-rate Galapagos Spreading Center (GSC) experiences decreasing magma supply along axis with increasing distance from the nearby Galapagos hotspot. This allows us to explore the effects of variable magma supply on eruptive frequency, size, and style. Two contrasting sites on the GSC were mapped using high-resolution swath bathymetry, submersible observations, and camera tow photography. Individual eruptive units have been identified on the basis of these data and observations, as well sample geochemistry. In order to construct an eruptive history and to make broader interpretations regarding eruptive processes, it is necessary to place relative and absolute age constraints on these units. We present age determinations derived from geomagnetic paleointensity experiments at one of the study sites, centered at ~91°55'W, where increased magma supply from the hotspot results in an axial high. Due to the near monotonic decrease in geomagnetic paleointensity over the past ~500+ years, it is possible to infer relative age and to place approximate age constraints on eruptive units on the basis of their experimentally-determined paleointensity. Four of the largest identified units have been selected as a test case. Results suggest that the youngest flow is approximately 40 ± 30 years old. This flow unit is ~5 km long by 1 km wide, centered on the rise axis. An older flow (~180 ± 30 years old), also centered along the rise axis, lies to the west and its ~7 km along-axis exposure is interrupted by a large, flat-topped seamount. A number of active hydrothermal chimneys sit atop this flow unit, the heat source for which we infer to be related to the younger flow to the east or to a more recent shallow intrusion. The oldest documented flow is roughly 400 years old and is exposed slightly off-axis to the north of the two younger flows. The paleointensity-derived flow ages are consistent with available geological constraints on relative age. Based on

  16. School-time Extension: Are the School Structure’s Hard Components Modified? Literature Review on the Subject

    Directory of Open Access Journals (Sweden)

    Soledad Vercellino

    2012-12-01

    Full Text Available For more than two decades we have witnessed in Latin America –in Argentina particularly– the development of policies to expand the school day. We understand that the implementation of such policies is an opportunity to observe the behavior of the school’s behavior faced with the attempt to modify one of its hardest components –school-time–; it becomes also a natural laboratory to analyze how much does the traditional organization of school-time can resist, how does it change and how do these changes (if implemented impact the rest of the school components (spaces, groups, etc.. This paper shows the state of the art of the most significant studies in two research fields, in the context of primary education, on this matter: on the one hand, the studies related to organization and extension of school time and, on the other hand, research on the structural and structuring components of school-related aspects. The literature review indicates that studies on school-time and on the corresponding extension policies and programs do not report the difficulties found when trying to modify the hard components of the school system. Studies with the ‘school system’ as object of study have not approached the numerous school-time extension experiences, although time is one of the structural elements of the system.

  17. Variance-Constrained Robust Estimation for Discrete-Time Systems with Communication Constraints

    Directory of Open Access Journals (Sweden)

    Baofeng Wang

    2014-01-01

    Full Text Available This paper is concerned with a new filtering problem in networked control systems (NCSs subject to limited communication capacity, which includes measurement quantization, random transmission delay, and packets loss. The measurements are first quantized via a logarithmic quantizer and then transmitted through a digital communication network with random delay and packet loss. The three communication constraints phenomena which can be seen as a class of uncertainties are formulated by a stochastic parameter uncertainty system. The purpose of the paper is to design a linear filter such that, for all the communication constraints, the error state of the filtering process is mean square bounded and the steady-state variance of the estimation error for each state is not more than the individual prescribed upper bound. It is shown that the desired filtering can effectively be solved if there are positive definite solutions to a couple of algebraic Riccati-like inequalities or linear matrix inequalities. Finally, an illustrative numerical example is presented to demonstrate the effectiveness and flexibility of the proposed design approach.

  18. A Hard Day’s Knights: Movie Time Travel, the Middle Ages, and a New Millenium

    Directory of Open Access Journals (Sweden)

    John Engle

    2012-10-01

    Full Text Available This article addresses the cinematic treatment of the Middle Ages through an analysis of two recent mass-audience American films, Black Knight and Timeline, both of which feature time travel as a leading plot element. Providing context for this discussion is a brief analysis of other similar films, as well as remarks regarding Twain's Connecticut Yankee, Ruskin's The Stones of Venice, and The Idylls of the King by Tennyson. As in these other works, the films in question use certain popular stereotypes of the Middle Ages—endemic violence, rigid class distinctions, religious fanaticism, spiritual cohesion, etc.—as lens through which to view the contemporary world. In addition to their roles as comic or action entertainment vehicles, Black Knight indirectly addresses American individualism and a cutthroat modern corporate culture, whereas Timeline touches upon millennial anxiety, '90's ethnic cleansing, and the American misadventure in Iraq.

  19. Multimodality Prediction of Chaotic Time Series with Sparse Hard-Cut EM Learning of the Gaussian Process Mixture Model

    Science.gov (United States)

    Zhou, Ya-Tong; Fan, Yu; Chen, Zi-Yi; Sun, Jian-Cheng

    2017-05-01

    The contribution of this work is twofold: (1) a multimodality prediction method of chaotic time series with the Gaussian process mixture (GPM) model is proposed, which employs a divide and conquer strategy. It automatically divides the chaotic time series into multiple modalities with different extrinsic patterns and intrinsic characteristics, and thus can more precisely fit the chaotic time series. (2) An effective sparse hard-cut expectation maximization (SHC-EM) learning algorithm for the GPM model is proposed to improve the prediction performance. SHC-EM replaces a large learning sample set with fewer pseudo inputs, accelerating model learning based on these pseudo inputs. Experiments on Lorenz and Chua time series demonstrate that the proposed method yields not only accurate multimodality prediction, but also the prediction confidence interval. SHC-EM outperforms the traditional variational learning in terms of both prediction accuracy and speed. In addition, SHC-EM is more robust and insusceptible to noise than variational learning. Supported by the National Natural Science Foundation of China under Grant No 60972106, the China Postdoctoral Science Foundation under Grant No 2014M561053, the Humanity and Social Science Foundation of Ministry of Education of China under Grant No 15YJA630108, and the Hebei Province Natural Science Foundation under Grant No E2016202341.

  20. Constraints on the timing of the Moon-forming giant impact from MORB Xe isotopes

    Science.gov (United States)

    Parai, R.; Mukhopadhyay, S.

    2014-12-01

    As Earth accreted, volatiles were delivered by accreting material and lost by degassing and impact-driven ejection to space. The Moon-forming giant impact initiated the final catastrophic outgassing and bulk volatile ejection event on the early Earth. I-Pu-U-Xe systematics provide a powerful tool to probe degassing of the early Earth. Radiogenic 129Xe was produced by β-decay of the extinct nuclide 129I (t1/2 = 15.7 Ma) in the first ~90 Myr of Earth history. Fissiogenic 131Xe, 132Xe, 134Xe, 136Xe were produced in distinct, characteristic proportions by the fission of extinct short-lived 244Pu (t1/2 = 80.0 Myr) and extant long-lived 238U (t1/2 = 4.468 Gyr). Here we present radiogenic and fission Xe data in basalts from the Southwest Indian Ridge, and discuss them with other mantle-derived samples to shed light on early Earth volatile accretion and loss. Based on the ratio of radiogenic 129Xe to plutogenic 136Xe determined for the MORB source, we calculate an I-Pu-Xe closure age for the upper mantle of ~44-70 Myr after the start of the Solar System. The closure age should correspond to the end of catastrophic mantle outgassing during accretion, and thus constrains the age of the last giant impact (LGI). Our closure age is significantly older than previous Xe closure age determinations of ~100 Myr, and is also older than some direct radiometric ages of lunar crustal samples. In order to explore the effects of accretion timescales, partial early retention of Xe, and degassing associated with long-term mantle processing on Xe closure age, we develop a new model of I-Pu-U-Xe systematics. We find that for LGI's between ~35 and 70 Myr after the start of the Solar System, we are able to satisfy constraints on I-Pu-U-Xe systematics simultaneously without invoking partial retention of Xe prior to the last giant impact. For LGI's after ~80 Myr, partial retention of Xe prior to the LGI is required. Non-zero early retention of Xe is necessary to explain the budgets of primordial

  1. Functional brain networks: great expectations, hard times and the big leap forward.

    Science.gov (United States)

    Papo, David; Zanin, Massimiliano; Pineda-Pardo, José Angel; Boccaletti, Stefano; Buldú, Javier M

    2014-10-05

    Many physical and biological systems can be studied using complex network theory, a new statistical physics understanding of graph theory. The recent application of complex network theory to the study of functional brain networks has generated great enthusiasm as it allows addressing hitherto non-standard issues in the field, such as efficiency of brain functioning or vulnerability to damage. However, in spite of its high degree of generality, the theory was originally designed to describe systems profoundly different from the brain. We discuss some important caveats in the wholesale application of existing tools and concepts to a field they were not originally designed to describe. At the same time, we argue that complex network theory has not yet been taken full advantage of, as many of its important aspects are yet to make their appearance in the neuroscience literature. Finally, we propose that, rather than simply borrowing from an existing theory, functional neural networks can inspire a fundamental reformulation of complex network theory, to account for its exquisitely complex functioning mode. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  2. Radiation hardness and precision timing study of silicon detectors for the CMS High Granularity Calorimeter (HGC)

    Energy Technology Data Exchange (ETDEWEB)

    Currás, Esteban, E-mail: ecurrasr@cern.ch [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Instituto de Física de Cantabria (CSIC-UC), Avda. los Castros s/n, E-39005 Santander (Spain); Fernández, Marcos [Instituto de Física de Cantabria (CSIC-UC), Avda. los Castros s/n, E-39005 Santander (Spain); Gallrapp, Christian [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Gray, Lindsey [Fermilab, Wilson Street and Kirk Road, Batavia, IL 60510-5011, Illinois (United States); Mannelli, Marcello [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Meridiani, Paolo [Istituto Nazionale Di Fisica Nucleare – Sezione di Roma, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Moll, Michael [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Nourbakhsh, Shervin [University of Minnesota, Minneapolis, MN 55455 (United States); Scharf, Christian [Hamburg University, Notkestraße 85, 22607 Hamburg (Germany); Silva, Pedro [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Steinbrueck, Georg [Hamburg University, Notkestraße 85, 22607 Hamburg (Germany); Fatis, Tommaso Tabarelli de [Istituto Nazionale di Fisica Nucleare – Sezione di Milano-Bicocca Piazza della Scienza 3, 20126 Milano (Italy); Vila, Iván [Instituto de Física de Cantabria (CSIC-UC), Avda. los Castros s/n, E-39005 Santander (Spain)

    2017-02-11

    The high luminosity upgraded LHC or Phase-II is expected to increase the instantaneous luminosity by a factor of 10 beyond the LHC's design value, expecting to deliver 250 fb{sup −1} per year for a further 10 years of operation. Under these conditions the performance degradation due to integrated radiation dose will need to be addressed. The CMS collaboration is planning to upgrade the forward calorimeters. The replacement is called the High Granularity Calorimeter (HGC) and it will be realized as a sampling calorimeter with layers of silicon detectors interleaved. The sensors will be realized as pad detectors with sizes of less that ∼1.0 cm{sup 2} and an active thickness between 100 and 300 μm depending on the position, respectively, the expected radiation levels. For an integrated luminosity of 3000 fb{sup −1}, the electromagnetic calorimetry will sustain integrated doses of 1.5 MGy (150 Mrads) and neutron fluences up to 10{sup 16} neq/cm{sup 2}. A radiation tolerance study after neutron irradiation of 300, 200, and 100 μm n-on-p and p-on-n silicon pads irradiated to fluences up to 1.6×10{sup 16} neq/cm{sup 2} is presented. The properties of these diodes studied before and after irradiation were leakage current, capacitance, charge collection efficiency, annealing effects and timing capability. The results of these measurements validate these sensors as candidates for the HGC system.

  3. Linguistic embodiment and verbal constraints: human cognition and the scales of time

    DEFF Research Database (Denmark)

    Cowley, Stephen

    2014-01-01

    Using radical embodied cognitive science, the paper offers the hypothesis that language is symbiotic: its agent-environment dynamics arise as linguistic embodiment is managed under verbal constraints. As a result, co-action grants human agents the ability to use a unique form of phenomenal...... with experience of wordings. The latter arise in making and tracking phonetic gestures that, crucially, mesh use of artifice, cultural products and impersonal experience. As observers, living human beings gain dispositions to display and use social subjectivity. Far from using brains to “process” verbal content......, linguistic symbiosis grants access to diachronic resources. On this distributed-ecological view, language can thus be redefined as: “activity in which wordings play a part.”...

  4. Spectral and Timing Properties of IGR J17091-3624 in the Rising Hard State During Its 2016 Outburst

    Science.gov (United States)

    Xu, Yanjun; Harrison, Fiona; Fuerst, Felix; Garcia, Javier; Walton, Dom; Tomsick, John

    2017-08-01

    We present a spectral and timing study of the NuSTAR and Swift observations of IGR J17091-3624 in the hard state during its outburst in 2016. IGR J17091-3624 is a galactic black hole binary candidate that has been previously observed to display variability patterns similar to GRS 1915+105, despite the apparent faintness compared to its counterpart. Disk reflection features are clearly revealed in the NuSTAR data taken in three epochs. Fitting with relativistic reflection models reveals the accretion disk is truncated during all epochs and the modeling favors a low disk inclination. The source flux increased by ~50% during the observations, the steepening of the spectral continuum is accompanied by a declination in the high energy cut-off. A type-C QPO increasing in frequency is detected in the NuSTAR data. In addition, we find a secondary peak centered at about 2.3 times the fundamental QPO frequency in the power spectra. This unconventional frequency questions the harmonic origin of the feature. We investigate the evolution of the timing and spectral properties on the rising phase of the outburst and discuss its physical implications.

  5. Linguistic embodiment and verbal constraints: human cognition and the scales of time

    Science.gov (United States)

    Cowley, Stephen J.

    2014-01-01

    Using radical embodied cognitive science, the paper offers the hypothesis that language is symbiotic: its agent-environment dynamics arise as linguistic embodiment is managed under verbal constraints. As a result, co-action grants human agents the ability to use a unique form of phenomenal experience. In defense of the hypothesis, I stress how linguistic embodiment enacts thinking: accordingly, I present auditory and acoustic evidence from 750 ms of mother-daughter talk, first, in fine detail and, then, in narrative mode. As the parties attune, they use a dynamic field to co-embody speech with experience of wordings. The latter arise in making and tracking phonetic gestures that, crucially, mesh use of artifice, cultural products and impersonal experience. As observers, living human beings gain dispositions to display and use social subjectivity. Far from using brains to “process” verbal content, linguistic symbiosis grants access to diachronic resources. On this distributed-ecological view, language can thus be redefined as: “activity in which wordings play a part.” PMID:25324799

  6. Real-Time Attitude Control Algorithm for Fast Tumbling Objects under Torque Constraint

    Science.gov (United States)

    Tsuda, Yuichi; Nakasuka, Shinichi

    This paper describes a new control algorithm for achieving any arbitrary attitude and angular velocity states of a rigid body, even fast and complicated tumbling rotations, under some practical constraints. This technique is expected to be applied for the attitude motion synchronization to capture a non-cooperative, tumbling object in such missions as removal of debris from orbit, servicing broken-down satellites for repairing or inspection, rescue of manned vehicles, etc. For this objective, we have introduced a novel control algorithm called Free Motion Path Method (FMPM) in the previous paper, which was formulated as an open-loop controller. The next step of this consecutive work is to derive a closed-loop FMPM controller, and as the preliminary step toward the objective, this paper attempts to derive a conservative state variables representation of a rigid body dynamics. 6-Dimensional conservative state variables are introduced in place of general angular velocity-attitude angle representation, and how to convert between both representations are shown in this paper.

  7. Multiple-access interference in 2-D wavelength/time optical CDMA system with optical hard-limiters

    Science.gov (United States)

    Chovan, Jozef; Uherek, František

    2005-08-01

    In this paper we present the proposed modification of 2-D wavelength/time (WIT) decoder1 by placing the second optical hard-limiter (0-HL) after decoder"s last optical coupler. The MA1 improvement of the 2-D W/T Optical Code Division Multiple Access (0-CDMA) system for the cases of 2D WIT decoder with one and with two 0-HLs is analyzed. Average value of signal-to-interference difference (SID) is used as the MA1 merit. The model of such 2D W/T 0-CDMA system for numerical calculation of the SID is proposed and presented in this paper. In the analyzed system, 2-D WIT Generalized Multiwavelength Prime Codewords (GMWPC), which are generated by algorithm reported in2 are used for achieving multiple-access. We assume the implemented 0-HL proposed in 3. The properties of such 0-HL were approximated [4] and its two ideality parameters, which characterize the measure of its ideality, were defined. The input and output time optical pulses sequence of W/T 0-CDMA decoder is numerical simulated. Dependencies of SID versus the weight of codeword and the number of active users in the system are presented. The influence of the properties used 0-HLs is evaluated.

  8. Effect of different exposure times on microwave irradiation on the disinfection of a hard chairside reline resin.

    Science.gov (United States)

    Mima, Ewerton G; Pavarina, Ana Claudia; Neppelenbroek, Karin Hermana; Vergani, Carlos Eduardo; Spolidorio, Denise Madalena P; Machado, Ana Lucia

    2008-06-01

    This study evaluated the effectiveness of different exposure times of microwave irradiation on the disinfection of a hard chairside reline resin. Sterile specimens were individually inoculated with one of the tested microorganisms (Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Bacillus subtilis) and incubated for 24 hours at 37 degrees C. For each microorganism, 10 specimens were not microwaved (control), and 50 specimens were microwaved. Control specimens were individually immersed in sterile saline, and replicate aliquots of serial dilutions were plated on selective media appropriate for each organism. Irradiated specimens were immersed in water and microwaved at 650 W for 1, 2, 3, 4, or 5 minutes before serial dilutions and platings. After 48 hours of incubation, colonies on plates were counted. Irradiated specimens were also incubated for 7 days. Some specimens were prepared for scanning electron microscopic (SEM) analysis. Specimens irradiated for 3, 4, and 5 minutes showed sterilization. After 2 minutes of irradiation, specimens inoculated with C. albicans were sterilized, whereas those inoculated with bacteria were disinfected. One minute of irradiation resulted in growth of all microorganisms. SEM examination indicated alteration in cell morphology of sterilized specimens. The effectiveness of microwave irradiation was improved as the exposure time increased. This study suggests that 3 minutes of microwave irradiation can be used for acrylic resin sterilization, thus preventing cross-contamination.

  9. Cyclic Hardness Test PHYBALCHT: A New Short-Time Procedure to Estimate Fatigue Properties of Metallic Materials

    Science.gov (United States)

    Kramer, Hendrik; Klein, Marcus; Eifler, Dietmar

    Conventional methods to characterize the fatigue behavior of metallic materials are very time and cost consuming. That is why the new short-time procedure PHYBALCHT was developed at the Institute of Materials Science and Engineering at the University of Kaiserslautern. This innovative method requires only a planar material surface to perform cyclic force-controlled hardness indentation tests. To characterize the cyclic elastic-plastic behavior of the test material the change of the force-indentation-depth-hysteresis is plotted versus the number of indentation cycles. In accordance to the plastic strain amplitude the indentation-depth width of the hysteresis loop is measured at half minimum force and is called plastic indentation-depth amplitude. Its change as a function of the number of cycles of indentation can be described by power-laws. One of these power-laws contains the hardening-exponentCHT e II , which correlates very well with the amount of cyclic hardening in conventional constant amplitude fatigue tests.

  10. (Q, R inventory model with service level constraint and variable lead time in fuzzy-stochastic environment

    Directory of Open Access Journals (Sweden)

    Hardik Soni

    2011-10-01

    Full Text Available In today's global marketplace, individual firms do not compete as independent entities rather as an integral part of a supply chain. Uncertainty is the main attribute in managing the supply chains. Accordingly, we develop a (Q, R inventory model with service level constraint and variable lead-time in fuzzy-stochastic environment. In addition, the triangular fuzzy numbers counts upon lead-time are used to construct fuzzy-stochastic lead-time demand. Using credibility criterion, the expected shortages are calculated. Without loss of generality, we assume that all the observed values of the fuzzy random variable, representing the demand are triangular fuzzy numbers. Consequently, the value of total expected cost in the fuzzy sense is derived using the expected value criterion or credibility criterion. To determine an optimal policy, a numerical technique is presented and the results are analyzed using scan and zoom for constraint optimization. Finally, in order to demonstrate the accuracy and effectiveness of the proposed model, numerical example and sensitivity analysis are also included.

  11. Interaction between sodium chloride and texture in semi-hard Danish cheese as affected by brining time, DL-starter culture, chymosin type and cheese ripening

    DEFF Research Database (Denmark)

    Akkerman, Marije; Søndergaard Kristensen, Lise; Jespersen, Lene

    2017-01-01

    Reduced NaCl in semi-hard cheeses greatly affects textural and sensory properties. The interaction between cheese NaCl concentration and texture was affected by brining time (0-28 h), . dl-starter cultures (C1, C2, and C3), chymosin type (bovine or camel), and ripening time (1-12 weeks). Cheese Na...

  12. Planning virtual infrastructures for time critical applications with multiple deadline constraints

    NARCIS (Netherlands)

    Wang, J.; Taal, A.; Martin, P.; Hu, Y.; Zhou, H.; Pang, J.; de Laat, C.; Zhao, Z.

    2017-01-01

    Executing time critical applications within cloud environments while satisfying execution deadlines and response time requirements is challenging due to the difficulty of securing guaranteed performance from the underlying virtual infrastructure. Cost-effective solutions for hosting such

  13. Hard and soft selection on phenology through seasonal shifts in the general and social environments: A study on plant emergence time.

    Science.gov (United States)

    Weis, Arthur E; Turner, Kyle M; Petro, Bergita; Austen, Emily J; Wadgymar, Susana M

    2015-06-01

    The timing of transition out of one life-history phase determines where in the seasonal succession of environments the next phase is spent. Shifts in the general environment (e.g., seasonal climate) affect the expected fitness for particular transition dates. Variation in transition date also leads to temporal variation in the social environment. For instance, early transition may confer a competitive advantage over later individuals. If so, the social environment will impose frequency- and density-dependent selection components. In effect, the general environment imposes hard selection, whereas the social environment imposes soft selection on phenology. We examined hard and soft selection on seedling emergence time in an experiment on Brassica rapa. In monoculture (uniform social environment), early emergence results in up to a 1.5-fold increase in seed production. In bicultures (heterogeneous social environment), early-emerging plants capitalized on their head start, suppressing their late neighbors and increasing their fitness advantage to as much as 38-fold, depending on density. We devised a novel adaptation of contextual analysis to partition total selection (i.e., cov(ω, z)) into the hard and soft components. Hard and soft components had similar strengths at low density, whereas soft selection was five times stronger than hard at high density. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  14. Impact of optimal load response to real-time electricity price on power system constraints in Denmark

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte

    2010-01-01

    Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift their loads from high price periods to the low price periods in order to save their energy costs. The optimal load response to a real-time electricity price...... and may represent the future of electricity markets in some ways, is chosen as the studied power system in this paper. A distribution system where wind power capacity is 126% of maximum loads is chosen as the study case. This paper presents a nonlinear load optimization method to real-time power price...... for demand side management in order to save the energy costs as much as possible. Simulation results show that the optimal load response to a real-time electricity price has some good impacts on power system constraints in a distribution system with high wind power penetrations....

  15. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng

    2015-12-10

    Most modern industrial and architectural designs need to satisfy the requirements of their targeted performance and respect the limitations of available fabrication technologies. At the same time, they should reflect the artistic considerations and personal taste of the designers, which cannot be simply formulated as optimization goals with single best solutions. This thesis aims at a general, flexible yet e cient computational framework for interactive creation, exploration and discovery of serviceable, constructible, and stylish designs. By formulating nonlinear engineering considerations as linear or quadratic expressions by introducing auxiliary variables, the constrained space could be e ciently accessed by the proposed algorithm Guided Projection, with the guidance of aesthetic formulations. The approach is introduced through applications in different scenarios, its effectiveness is demonstrated by examples that were difficult or even impossible to be computationally designed before. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application is extended to developable surfaces including origami with curved creases. Finally, general approaches to extend hard constraints and soft energies are discussed, followed by a concluding remark outlooking possible future studies.

  16. Quantum information density scaling and qubit operation time constraints of CMOS silicon-based quantum computer architectures

    Science.gov (United States)

    Rotta, Davide; Sebastiano, Fabio; Charbon, Edoardo; Prati, Enrico

    2017-06-01

    Even the quantum simulation of an apparently simple molecule such as Fe2S2 requires a considerable number of qubits of the order of 106, while more complex molecules such as alanine (C3H7NO2) require about a hundred times more. In order to assess such a multimillion scale of identical qubits and control lines, the silicon platform seems to be one of the most indicated routes as it naturally provides, together with qubit functionalities, the capability of nanometric, serial, and industrial-quality fabrication. The scaling trend of microelectronic devices predicting that computing power would double every 2 years, known as Moore's law, according to the new slope set after the 32-nm node of 2009, suggests that the technology roadmap will achieve the 3-nm manufacturability limit proposed by Kelly around 2020. Today, circuital quantum information processing architectures are predicted to take advantage from the scalability ensured by silicon technology. However, the maximum amount of quantum information per unit surface that can be stored in silicon-based qubits and the consequent space constraints on qubit operations have never been addressed so far. This represents one of the key parameters toward the implementation of quantum error correction for fault-tolerant quantum information processing and its dependence on the features of the technology node. The maximum quantum information per unit surface virtually storable and controllable in the compact exchange-only silicon double quantum dot qubit architecture is expressed as a function of the complementary metal-oxide-semiconductor technology node, so the size scale optimizing both physical qubit operation time and quantum error correction requirements is assessed by reviewing the physical and technological constraints. According to the requirements imposed by the quantum error correction method and the constraints given by the typical strength of the exchange coupling, we determine the workable operation frequency

  17. The Impact of Resource Constraints on the Psychological Well-Being of Survivors of Intimate Partner Violence over Time

    Science.gov (United States)

    Beeble, Marisa L.; Bybee, Deborah; Sullivan, Cris M.

    2010-01-01

    This study examined the impact of resource constraints on the psychological well-being of survivors of intimate partner violence (IPV), testing whether resource constraints is one mechanism that partially mediates the relationship between IPV and women's well-being. Although within-woman changes in resource constraints did not mediate the…

  18. Minimum vehicle fleet size under time window constraints at a container terminal

    NARCIS (Netherlands)

    Vis, I.F.A.; de Koster, R.; Savelsbergh, M.W.P.

    2005-01-01

    Products can be transported in containers from one port to another. At a container terminal these containers are transshipped from one mode of transportation to another. Cranes remove containers from a ship and put them at a certain time (i.e., release time) into a buffer area with limited capacity.

  19. Timing Constraints Based High Performance Des Design And Implementation On 28nm FPGA

    DEFF Research Database (Denmark)

    Thind, Vandana; Pandey, Sujeet; Hussain, Dil muhammed Akbar

    2018-01-01

    in this work, we are going to implement DES Algorithm on 28nm Artix-7 FPGA. To achieve high performance design goal, we are using minimum period, maximum frequency, minimum low pulse, minimum high pulse for different cases of worst case slack, maximum delay, setup time, hold time and data skew path...

  20. Robust and Energy-Efficient Ultra-Low-Voltage Circuit Design under Timing Constraints in 65/45 nm CMOS

    Directory of Open Access Journals (Sweden)

    David Bol

    2011-01-01

    Full Text Available Ultra-low-voltage operation improves energy efficiency of logic circuits by a factor of 10×, at the expense of speed, which is acceptable for applications with low-to-medium performance requirements such as RFID, biomedical devices and wireless sensors. However, in 65/45 nm CMOS, variability and short-channel effects significantly harm robustness and timing closure of ultra-low-voltage circuits by reducing noise margins and jeopardizing gate delays. The consequent guardband on the supply voltage to meet a reasonable manufacturing yield potentially ruins energy efficiency. Moreover, high leakage currents in these technologies degrade energy efficiency in case of long stand-by periods. In this paper, we review recently published techniques to design robust and energy-efficient ultra-low-voltage circuits in 65/45 nm CMOS under relaxed yet strict timing constraints.

  1. On the Use of Time-Limited Information for Maintenance Decision Support: A Predictive Approach under Maintenance Constraints

    Directory of Open Access Journals (Sweden)

    E. Khoury

    2013-01-01

    Full Text Available This paper deals with a gradually deteriorating system operating under an uncertain environment whose state is only known on a finite rolling horizon. As such, the system is subject to constraints. Maintenance actions can only be planned at imposed times called maintenance opportunities that are available on a limited visibility horizon. This system can, for example, be a commercial vehicle with a monitored critical component that can be maintained only in some specific workshops. Based on the considered system, we aim to use the monitoring data and the time-limited information for maintenance decision support in order to reduce its costs. We propose two predictive maintenance policies based, respectively, on cost and reliability criteria. Classical age-based and condition-based policies are considered as benchmarks. The performance assessment shows the value of the different types of information and the best way to use them in maintenance decision making.

  2. Radio Resource Allocation for Real-Time Traffic with Multi-Level Delay Constraint in OFDMA System

    Science.gov (United States)

    Hwang, Sungho; Park, Jeongsik; Cho, Ho-Shin

    In this paper, an efficient radio resource allocation scheme for OFDMA systems is proposed, which follows two steps to take care of real-time traffic characterized with multi-level delay constraints. Urgent packets, those with imminent deadlines, are released first in step 1. After that the remaining channel resources are managed in such a way that overall throughput is maximized at Step 2. In this work, 2-dimensional diversity over multiple sub-bands and multiple users are jointly considered. The proposed scheme is compared with existing schemes designed for real-time traffic such as Exponential Scheduling (EXP) scheme, Modified Largest Weighted Delay First (M-LWDF) scheme, and Round robin scheme in terms of the packet discard probability and throughput. Numerical results show that the proposed scheme performs much better than the aforementioned ones in terms of the packet discard probability, while slightly better in terms of throughput.

  3. Structure and Composition of the Distant Lunar Exosphere: Constraints from ARTEMIS Observations of Ion Acceleration in Time-Varying Fields

    Science.gov (United States)

    Halekas, J. S.; Poppe, A. R.; Farrell, W. M.; McFadden, J. P.

    2016-01-01

    By analyzing the trajectories of ionized constituents of the lunar exosphere in time-varying electromagnetic fields, we can place constraints on the composition, structure, and dynamics of the lunar exosphere. Heavy ions travel slower than light ions in the same fields, so by observing the lag between field rotations and the response of ions from the lunar exosphere, we can place constraints on the composition of the ions. Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) provides an ideal platform to utilize such an analysis, since its two-probe vantage allows precise timing of the propagation of field discontinuities in the solar wind, and its sensitive plasma instruments can detect the ion response. We demonstrate the utility of this technique by using fully time-dependent charged particle tracing to analyze several minutes of ion observations taken by the two ARTEMIS probes 3000-5000 km above the dusk terminator on 25 January 2014. The observations from this time period allow us to reach several interesting conclusions. The ion production at altitudes of a few hundred kilometers above the sunlit surface of the Moon has an unexpectedly significant contribution from species with masses of 40 amu or greater. The inferred distribution of the neutral source population has a large scale height, suggesting that micrometeorite impact vaporization and/or sputtering play an important role in the production of neutrals from the surface. Our observations also suggest an asymmetry in ion production, consistent with either a compositional variation in neutral vapor production or a local reduction in solar wind sputtering in magnetic regions of the surface.

  4. The acceleration time of anomalous cosmic rays: Observational constraints from Pioneer 10 data

    National Research Council Canada - National Science Library

    Scherer, K; Fichtner, H; Fahr, H. J

    1998-01-01

    ... radiation as a proxy for the long‐term solar activity, a comparison of the correlation functions of the anomalous and galactic cosmic ray data reveals a significantly greater phase shift in the time variation of the former...

  5. Economic Impact of Harvesting Corn Stover under Time Constraint: The Case of North Dakota

    Directory of Open Access Journals (Sweden)

    Thein A. Maung

    2013-01-01

    Full Text Available This study examines the impact of stochastic harvest field time on profit maximizing potential of corn cob/stover collection in North Dakota. Three harvest options are analyzed using mathematical programming models. Our findings show that under the first corn grain only harvest option, farmers are able to complete harvesting corn grain and achieve maximum net income in a fairly short amount of time with existing combine technology. However, under the second simultaneous corn grain and cob (one-pass harvest option, farmers generate lower net income compared to the net income of the first option. This is due to the slowdown in combine harvest capacity as a consequence of harvesting corn cobs. Under the third option of separate corn grain and stover (two-pass harvest option, time allocation is the main challenge and our evidence shows that with limited harvest field time available, farmers find it optimal to allocate most of their time harvesting grain and then proceed to harvest and bale stover if time permits at the end of harvest season. The overall findings suggest is that it would be more economically efficient to allow a firm that is specialized in collecting biomass feedstock to participate in cob/stover harvest business.

  6. Multi-Objective Lead-Time Control Problem with Stochastic Constraints

    Directory of Open Access Journals (Sweden)

    M. Molavi

    2014-10-01

    Full Text Available This research intends to find out any development of a robust multi-objective for lead time optimal control problem in a multi-stage assembly system model. Assembly system modeling is possible by the help of the open queue network. A working station includes one or infinite servers and just manufacturing or assembly operations are performed therein. Each part has a separate entry process and independent of each other. It is completely based upon Poisson process.Serving Lead Time of Stations are also independent of each other and therefore exponential distribution of each parameter is controllable. All stations have bounded uncertain unrecyclable wastes which are completely independent in compliance with Erlang distribution. Uncertainty in the problem parameters has been suggested as robust multi-objective optimal control model in which we have three incompatible target functions including cyclic operation cost minimization, average lead time minimization and lead time variance. Finally, target progress method has been applied in order to achieve serving optimal speeds and solve discrete time of the main problem approximately. The proposed model could present a suitable solution even for the same problem as mentioned in other related papers along with some considerable results in parameter uncertainty conditions.

  7. Wise Moves in Hard Times: Creating & Managing Resilient Colleges & Universities. The Jossey-Bass Higher and Adult Education Series. First Edition.

    Science.gov (United States)

    Leslie, David W.; Fretwell, E. K., Jr.

    Based on data gathered on-site at 13 colleges and universities, this volume offers an in-depth analysis of how colleges and universities have been affected by hard times, how they have risen to the challenges, and what their responses mean to the public and its support for higher education. Part 1 describes the study itself in detail and reports…

  8. Effects of Real-Time Captioning and Sign Language Interpreting on the Learning of College Students Who Are Deaf or Hard of Hearing

    Science.gov (United States)

    Smith-Pethybridge, Valorie

    2009-01-01

    College personnel are required to provide accommodations for students who are deaf and hard of hearing (D/HoH), but few empirical studies have been conducted on D/HoH students as they learn under the various accommodation conditions (sign language interpreting, SLI, real-time captioning, RTC, and both). Guided by the experiences of students who…

  9. Comparative Study of Motor Performance of Deaf and Hard of Hearing Students in Reaction Time, Visual-Motor Control and Upper Limb Speed and Dexterity Abilities

    Science.gov (United States)

    Gkouvatzi, Anastasia N.; Mantis, Konstantinos; Kambas, Antonis

    2010-01-01

    Using the Bruininks-Oseretsky Test the motor performance of 34 deaf--hard-of-hearing pupils, 6-14 year, was evaluated in reaction time, visual-motor control and upper limb speed and dexterity. The two-way ANOVA variance analysis for two independent variables, group, age, and the Post Hoc (Scheffe test) for multiple comparisons were used. The…

  10. Continuous Descent Approaches with Variable Flight-Path Angles under Time Constraints

    NARCIS (Netherlands)

    Sopjes, R.; De Jong, P.M.A.; Borst, C.; Van Paassen, M.M.; Mulder, M.

    2011-01-01

    In order to reduce noise nuisance around Schiphol Airport, a Continuous Descent Approach procedure was introduced in the late ’90s. Unfortunately, because unpredictable individual aircraft behavior lead to increased landing intervals for this procedure, it is currently only applied during night time

  11. 3D time-dependent flow computations using a molecular stress function model with constraint release

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz

    2002-01-01

    The numerical simulation of time dependent viscoelastic flow (in three dimensions) is of interest in connection with a variety of polymer processing operations. The application of the numerical simulation techniques is in the analysis and design of polymer processing problems. This is operations,......, such as thermoforming, blow moulding, compression moulding, gas-assisted injection moulding, simultaneous multi-component injection moulding....

  12. Territory-Based Vehicle Routing in the Presence of Time-Window Constraints

    NARCIS (Netherlands)

    Schneider, M.; Stenger, A.; Schwahn, F; Vigo, D.

    2015-01-01

    Territory-based routing approaches (TBRAs) are commonly used to achieve high service consistency, e.g., in the small package shipping industry, but their drawback is a decline in routing flexibility. Consequently, a high percentage of time-definite deliveries, as common in the small package shipping

  13. Prepupal building behavior in Drosophila melanogaster and its evolution under resource and time constraints.

    Science.gov (United States)

    Narasimha, Sunitha; Kolly, Sylvain; Sokolowski, Marla B; Kawecki, Tadeusz J; Vijendravarma, Roshan K

    2015-01-01

    Structures built by animals are a widespread and ecologically important 'extended phenotype'. While its taxonomic diversity has been well described, factors affecting short-term evolution of building behavior within a species have received little experimental attention. Here we describe how, given the opportunity, wandering Drosophila melanogaster larvae often build long tunnels in agar substrates and embed their pupae within them. These embedded larvae are characterized by a longer egg-to-pupariation developmental time than larvae that pupate on the surface. Assuming that such building behaviors are likely to be energetically costly and/or time consuming, we hypothesized that they should evolve to be less pronounced under resource or time limitation. In accord with this prediction, larvae from populations evolved for 160 generations under a regime that combines larval malnutrition with limited developmental time dug shorter tunnels than larvae from control unselected populations. However, the proportion of larvae that embedded before pupation did not differ between the malnutrition-adapted and control populations, suggesting that tunnel length and likelihood of embedding before pupation are controlled by different genetic loci. The behaviors exhibited by wandering larvae of Drosophila melanogaster prior to pupation offer a model system to study evolution of animal building behaviors because the tunneling and embedding phenotypes are simple, facultative and highly variable.

  14. Prepupal building behavior in Drosophila melanogaster and its evolution under resource and time constraints.

    Directory of Open Access Journals (Sweden)

    Sunitha Narasimha

    Full Text Available Structures built by animals are a widespread and ecologically important 'extended phenotype'. While its taxonomic diversity has been well described, factors affecting short-term evolution of building behavior within a species have received little experimental attention. Here we describe how, given the opportunity, wandering Drosophila melanogaster larvae often build long tunnels in agar substrates and embed their pupae within them. These embedded larvae are characterized by a longer egg-to-pupariation developmental time than larvae that pupate on the surface. Assuming that such building behaviors are likely to be energetically costly and/or time consuming, we hypothesized that they should evolve to be less pronounced under resource or time limitation. In accord with this prediction, larvae from populations evolved for 160 generations under a regime that combines larval malnutrition with limited developmental time dug shorter tunnels than larvae from control unselected populations. However, the proportion of larvae that embedded before pupation did not differ between the malnutrition-adapted and control populations, suggesting that tunnel length and likelihood of embedding before pupation are controlled by different genetic loci. The behaviors exhibited by wandering larvae of Drosophila melanogaster prior to pupation offer a model system to study evolution of animal building behaviors because the tunneling and embedding phenotypes are simple, facultative and highly variable.

  15. Fast leaf-fitting with generalized underdose/overdose constraints for real-time MLC tracking

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Douglas, E-mail: douglas.moore@utsouthwestern.edu; Sawant, Amit [Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas 75390 (United States); Ruan, Dan [Department of Radiation Oncology, University of California, Los Angeles, California 90095 (United States)

    2016-01-15

    Purpose: Real-time multileaf collimator (MLC) tracking is a promising approach to the management of intrafractional tumor motion during thoracic and abdominal radiotherapy. MLC tracking is typically performed in two steps: transforming a planned MLC aperture in response to patient motion and refitting the leaves to the newly generated aperture. One of the challenges of this approach is the inability to faithfully reproduce the desired motion-adapted aperture. This work presents an optimization-based framework with which to solve this leaf-fitting problem in real-time. Methods: This optimization framework is designed to facilitate the determination of leaf positions in real-time while accounting for the trade-off between coverage of the PTV and avoidance of organs at risk (OARs). Derived within this framework, an algorithm is presented that can account for general linear transformations of the planned MLC aperture, particularly 3D translations and in-plane rotations. This algorithm, together with algorithms presented in Sawant et al. [“Management of three-dimensional intrafraction motion through real-time DMLC tracking,” Med. Phys. 35, 2050–2061 (2008)] and Ruan and Keall [Presented at the 2011 IEEE Power Engineering and Automation Conference (PEAM) (2011) (unpublished)], was applied to apertures derived from eight lung intensity modulated radiotherapy plans subjected to six-degree-of-freedom motion traces acquired from lung cancer patients using the kilovoltage intrafraction monitoring system developed at the University of Sydney. A quality-of-fit metric was defined, and each algorithm was evaluated in terms of quality-of-fit and computation time. Results: This algorithm is shown to perform leaf-fittings of apertures, each with 80 leaf pairs, in 0.226 ms on average as compared to 0.082 and 64.2 ms for the algorithms of Sawant et al., Ruan, and Keall, respectively. The algorithm shows approximately 12% improvement in quality-of-fit over the Sawant et al

  16. Real-time Observational Water Level Data Stream Online Filtering Method with Hydrological Changes Semantic Constraints

    Directory of Open Access Journals (Sweden)

    DING Yulin

    2015-12-01

    Full Text Available Irregular environmental changes and occasional instrument malfunctions have made noises and exceptions in observational data prominence. Therefore, before processing real-time water level data online, data cleaning is urgently needed to ensure data quality. Since traditional data filtering methods didn't take the data change pattern into consideration, these methods have encountered some severe problems, including the poor adaptability of filter model, the low estimation precision and prohibitively high calculation cost. To overcome these shortcomings, this paper presents a hydrological change semantics constrained online Kalman filtering method: creating dynamic semantic mapping between real-time data changing pattern and the rules of spatial-temporal hydrological process evolution; implementing the change semantic constrained Kalman filtering method to support the adaptive parameter optimization. Observational water level data streams of different precipitation scenarios are selected for testing. Experimental results prove that by means of this method, more accurate and reliable water level information can be available.

  17. A Utility Accrual Scheduling Algorithm for Real-Time Activities With Mutual Exclusion Resource Constraints

    Science.gov (United States)

    2006-01-01

    operating system or middleware) and one or more exception handlers in the application (in that order of execution). We refer to the time consumed by...common hardware platform). The experimental system is a Toshiba Satellite 1805-S254 laptop (one 1GHz Intel Pentium III processor, 256KB L2 cache, and...wherever proper. Many existing algorithms for overload scheduling consider step TUF’s, and mimic the behavior of EDF during under-loaded situations as

  18. Front-of-pack nutrition labels. Their effect on attention and choices when consumers have varying goals and time constraints.

    Science.gov (United States)

    van Herpen, Erica; Trijp, Hans C M van

    2011-08-01

    Although front-of-pack nutrition labeling can help consumers make healthier food choices, lack of attention to these labels limits their effectiveness. This study examines consumer attention to and use of three different nutrition labeling schemes (logo, multiple traffic-light label, and nutrition table) when they face different goals and resource constraints. To understand attention and processing of labels, various measures are used including self-reported use, recognition, and eye-tracking measures. Results of two experiments in different countries show that although consumers evaluate the nutrition table most positively, it receives little attention and does not stimulate healthy choices. Traffic-light labels and especially logos enhance healthy product choice, even when consumers are put under time pressure. Additionally, health goals of consumers increase attention to and use of nutrition labels, especially when these health goals concern specific nutrients. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. A fuzzy inventory model with unit production cost, time depended holding cost, with-out shortages under a space constraint: a parametric geometric programming approach

    OpenAIRE

    Sahidul Islam; Wasim Akram Mandal

    2017-01-01

    In this paper, an Inventory model with unit production cost, time depended holding cost, with-out shortages is formulated and solved. We have considered here a single objective inventory model. In most real world situation, the objective and constraint function of the decision makers are imprecise in nature, hence the coefficients, indices, the objective function and constraint goals are imposed here in fuzzy environment. Geometric programming provides a powerful tool for solving a variety of...

  20. Constraints on the Dynamical Environments of Supermassive Black-Hole Binaries Using Pulsar-Timing Arrays.

    Science.gov (United States)

    Taylor, Stephen R; Simon, Joseph; Sampson, Laura

    2017-05-05

    We introduce a technique for gravitational-wave analysis, where Gaussian process regression is used to emulate the strain spectrum of a stochastic background by training on population-synthesis simulations. This leads to direct Bayesian inference on astrophysical parameters. For pulsar timing arrays specifically, we interpolate over the parameter space of supermassive black-hole binary environments, including three-body stellar scattering, and evolving orbital eccentricity. We illustrate our approach on mock data, and assess the prospects for inference with data similar to the NANOGrav 9-yr data release.

  1. Linear time algorithms to construct populations fitting multiple constraint distributions at genomic scales.

    Science.gov (United States)

    Siragusa, Enrico; Haiminen, Niina; Utro, Filippo; Parida, Laxmi

    2017-10-09

    Computer simulations can be used to study population genetic methods, models and parameters, as well as to predict potential outcomes. For example, in plant populations, predicting the outcome of breeding operations can be studied using simulations. In-silico construction of populations with pre-specified characteristics is an important task in breeding optimization and other population genetic studies. We present two linear time Simulation using Best-fit Algorithms (SimBA) for two classes of problems where each co-fits two distributions: SimBA-LD fits linkage disequilibrium and minimum allele frequency distributions, while SimBA-hap fits founder-haplotype and polyploid allele dosage distributions. An incremental gap-filling version of previously introduced SimBA-LD is here demonstrated to accurately fit the target distributions, allowing efficient large scale simulations. SimBA-hap accuracy and efficiency is demonstrated by simulating tetraploid populations with varying numbers of founder haplotypes, we evaluate both a linear time greedy algoritm and an optimal solution based on mixed-integer programming. SimBA is available on http://researcher.watson.ibm.com/project/5669.

  2. Constraint Differentiation

    DEFF Research Database (Denmark)

    Mödersheim, Sebastian Alexander; Basin, David; Viganò, Luca

    2010-01-01

    We introduce constraint differentiation, a powerful technique for reducing search when model-checking security protocols using constraint-based methods. Constraint differentiation works by eliminating certain kinds of redundancies that arise in the search space when using constraints to represent...

  3. Reinforcement learning for adaptive optimal control of unknown continuous-time nonlinear systems with input constraints

    Science.gov (United States)

    Yang, Xiong; Liu, Derong; Wang, Ding

    2014-03-01

    In this paper, an adaptive reinforcement learning-based solution is developed for the infinite-horizon optimal control problem of constrained-input continuous-time nonlinear systems in the presence of nonlinearities with unknown structures. Two different types of neural networks (NNs) are employed to approximate the Hamilton-Jacobi-Bellman equation. That is, an recurrent NN is constructed to identify the unknown dynamical system, and two feedforward NNs are used as the actor and the critic to approximate the optimal control and the optimal cost, respectively. Based on this framework, the action NN and the critic NN are tuned simultaneously, without the requirement for the knowledge of system drift dynamics. Moreover, by using Lyapunov's direct method, the weights of the action NN and the critic NN are guaranteed to be uniformly ultimately bounded, while keeping the closed-loop system stable. To demonstrate the effectiveness of the present approach, simulation results are illustrated.

  4. A time-resolved model of the mesospheric Na layer: constraints on the meteor input function

    Directory of Open Access Journals (Sweden)

    J. M. C. Plane

    2004-01-01

    Full Text Available A time-resolved model of the Na layer in the mesosphere/lower thermosphere region is described, where the continuity equations for the major sodium species Na, Na+ and NaHCO3 are solved explicity, and the other short-lived species are treated in steady-state. It is shown that the diurnal variation of the Na layer can only be modelled satisfactorily if sodium species are permanently removed below about 85 km, both through the dimerization of NaHCO3 and the uptake of sodium species on meteoric smoke particles that are assumed to have formed from the recondensation of vaporized meteoroids. When the sensitivity of the Na layer to the meteoroid input function is considered, an inconsistent picture emerges. The ratio of the column abundance of Na+ to Na is shown to increase strongly with the average meteoroid velocity, because the Na is injected at higher altitudes. Comparison with a limited set of Na+ measurements indicates that the average meteoroid velocity is probably less than about 25 km s-1, in agreement with velocity estimates from conventional meteor radars, and considerably slower than recent observations made by wide aperture incoherent scatter radars. The Na column abundance is shown to be very sensitive to the meteoroid mass input rate, and to the rate of vertical transport by eddy diffusion. Although the magnitude of the eddy diffusion coefficient in the 80–90 km region is uncertain, there is a consensus between recent models using parameterisations of gravity wave momentum deposition that the average value is less than 3×105 cm2 s-1. This requires that the global meteoric mass input rate is less than about 20 td-1, which is closest to estimates from incoherent scatter radar observations. Finally, the diurnal variation in the meteoroid input rate only slight perturbs the Na layer, because the residence time of Na in the layer is several days, and diurnal effects are effectively averaged out.

  5. Fundamental computational constraints on the time course of perception and action.

    Science.gov (United States)

    Edelman, Shimon; Moyal, Roy

    2017-01-01

    A cognitive system faced with contingent events that cause rapid changes in sensory data may (i) incrementally incorporate new data into the ongoing perceptual and motor processing; or (ii) restart processing on each new event; or (iii) sample the data and hold onto the sample until its processing is complete, while disregarding any contingent changes. We offer a set of computational first-principles arguments for a hypothesis, according to which any system that contends with certain classes of perception and behavioral control tasks must include the sample-and-hold option (possibly alongside the other two, which may be useful in other tasks). This hypothesis has implications for understanding the dynamics of perception and action. In particular, a sample-and-hold channel necessarily processes sensory data on some kind of cycle (which does not imply precise periodicity). Further, being prepared to face the world at all times requires that the sampling that initiates each cycle be triggered by every significant action on part of the agent itself, such as saccades. We survey a range of evidence for the sample-and-hold functionality, touching upon diverse phenomena such as attentional blink and backward masking, the yoking of olfaction to respiration, thalamocortical interactions, and metastable brain dynamics in perception and consciousness. © 2017 Elsevier B.V. All rights reserved.

  6. Generalized time-dependent Schrödinger equation in two dimensions under constraints

    Science.gov (United States)

    Sandev, Trifce; Petreska, Irina; Lenzi, Ervin K.

    2018-01-01

    We investigate a generalized two-dimensional time-dependent Schrödinger equation on a comb with a memory kernel. A Dirac delta term is introduced in the Schrödinger equation so that the quantum motion along the x-direction is constrained at y = 0. The wave function is analyzed by using Green's function approach for several forms of the memory kernel, which are of particular interest. Closed form solutions for the cases of Dirac delta and power-law memory kernels in terms of Fox H-function, as well as for a distributed order memory kernel, are obtained. Further, a nonlocal term is also introduced and investigated analytically. It is shown that the solution for such a case can be represented in terms of infinite series in Fox H-functions. Green's functions for each of the considered cases are analyzed and plotted for the most representative ones. Anomalous diffusion signatures are evident from the presence of the power-law tails. The normalized Green's functions obtained in this work are of broader interest, as they are an important ingredient for further calculations and analyses of some interesting effects in the transport properties in low-dimensional heterogeneous media.

  7. Effect of different disinfecting procedures on the hardness and color stability of two maxillofacial elastomers over time

    Science.gov (United States)

    ELENI, Panagiota N.; KROKIDA, Magdalini K.; POLYZOIS, Gregory L.; GETTLEMAN, Lawrence

    2013-01-01

    Objective: Disinfection procedures often cause deterioration in a maxillofacial prosthesis. Color and hardness alterations could lead to a replacement of the prosthesis. Material and Methods: An experimental chlorinated polyethylene (CPE) and a commercial polydimethyl siloxane (PDMS) sample were treated with four different disinfection procedures for a period which simulates 1 year of clinical service. The applied disinfection procedures included microwave exposure and immersion in three solutions, sodium hypochlorite, neutral soap and a commercial disinfecting soap. Shore A hardness (ΔΗ) and color differences (ΔΕ) were determined before and after each procedure. All data were analyzed by Two Way Analysis of Variance (ANOVA) and Tukey's post hoc tests at a level of α=0.05. Results: The samples presented significant alterations in color and hardness after the different disinfection treatments. The color differences (ΔΕ) were at least eye detectable in all cases and clinically unacceptable in most of the cases, with values ranging from 1.51 to 4.15 and from 1.54 to 5.92 for the PDMS and CPE material, respectively. Hardness was decreased after all the disinfection procedures in the PDMS, while for the CPE, a decrement was observed after disinfection with sodium hypochlorite and neutral soap and an increment after microwave exposure and the disinfection with a commercial antimicrobial agent. The PDMS samples presented greater alterations in color and hardness after disinfection with sodium hypochlorite solution, while the microwave exposure caused negligible effects. The CPE samples were affected most after disinfection when treated with neutral soap, and more slightly when disinfected with sodium hypochlorite solution. Conclusions: The disinfection procedures caused alterations in color and hardness of the examined materials. The most suitable disinfection procedure for the PDMS material is microwave exposure, while disinfection with sodium hypochlorite

  8. The influence of the dwell time deviation constraint (DTDC) parameter on dosimetry with IPSA optimisation for HDR prostate brachytherapy.

    Science.gov (United States)

    Smith, Ryan L; Panettieri, Vanessa; Lancaster, Craig; Mason, Natasha; Franich, Rick D; Millar, Jeremy L

    2015-03-01

    To investigate how the dwell time deviation constraint (DTDC) parameter, applied to inverse planning by simulated annealing (IPSA) optimisation limits large dwell times from occurring in each catheter and to characterise the effect on the resulting dosimetry for prostate high dose rate (HDR) brachytherapy treatment plans. An unconstrained IPSA optimised treatment plan, using the Oncentra Brachytherapy treatment planning system (version 4.3, Nucletron an Elekta company, Elekta AB, Stockholm, Sweden), was generated for 20 consecutive HDR prostate brachytherapy patients, with the DTDC set to zero. Successive constrained optimisation plans were also created for each patient by increasing the DTDC parameter by 0.2, up to a maximum value of 1.0. We defined a "plan modulation index", to characterise the change of dwell time modulation as the DTDC parameter was increased. We calculated the dose volume histogram indices for the PTV (D90, V100, V150, V200%) and urethra (D10%) to characterise the effect on the resulting dosimetry. The average PTV D90% decreases as the DTDC is applied, on average by only 1.5 %, for a DTDC = 0.4. The measures of high dose regions in the PTV, V150 and V200%, increase on average by less than 5 and 2 % respectively. The net effect of DTDC on the modulation of dwell times has been characterised by the introduction of the plan modulation index. DTDC applied during IPSA optimisation of HDR prostate brachytherapy plans reduce the occurrence of large isolated dwell times within individual catheters. The mechanism by which DTDC works has been described and its effect on the modulation of dwell times has been characterised. The authors recommend using a DTDC parameter no greater than 0.4 to obtain a plan with dwell time modulation comparable to a geometric optimised plan. This yielded on average a 1.5 % decrease in PTV coverage and an acceptable increase in V150%, without compromising the urethral dose.

  9. The Bashgumbaz "ophiolites" of SE Pamir (Tajikistan): time constraints for the South Pamir accretion to Eurasia

    Science.gov (United States)

    Zanchetta, Stefano; Worthington, James; Angiolini, Lucia; Zanchi, Andrea

    2017-04-01

    -Th-Pb dating of zircons from a diorite provides a Carnian crystallization age. Deformation and metamorphism (up to greenschist facies) that affected the Bashgumbaz complex should therefore been placed in the Late Triassic. We suggest that the Bashgumbaz unit formed in a supra-subduction setting and was later underthrusted and then obducted onto the southern margin of the closing Rushan-Pshart ocean. The obduction of the Bashgumbaz ophiolites could be considered as a time-marker for the accretion of the South Pamir terrane to the Eurasian margin.

  10. Time constraints for post-LGM landscape response to deglaciation in Val Viola, Central Italian Alps

    Science.gov (United States)

    Scotti, Riccardo; Brardinoni, Francesco; Crosta, Giovanni Battista; Cola, Giuseppe; Mair, Volkmar

    2017-12-01

    , the timing of the main Val Viola rock avalanche, 7.7 ± 0.3 ka during the Holocene Thermal Optimum, suggests a possible causal linkage to permafrost degradation. Overall, Schmidt-hammer proved to be an effective, inexpensive and versatile tool for improving the spatial resolution of Val Viola post-LGM landscape history, starting from existing numerical age constrains.

  11. Neural-Dynamic-Method-Based Dual-Arm CMG Scheme With Time-Varying Constraints Applied to Humanoid Robots.

    Science.gov (United States)

    Zhang, Zhijun; Li, Zhijun; Zhang, Yunong; Luo, Yamei; Li, Yuanqing

    2015-12-01

    We propose a dual-arm cyclic-motion-generation (DACMG) scheme by a neural-dynamic method, which can remedy the joint-angle-drift phenomenon of a humanoid robot. In particular, according to a neural-dynamic design method, first, a cyclic-motion performance index is exploited and applied. This cyclic-motion performance index is then integrated into a quadratic programming (QP)-type scheme with time-varying constraints, called the time-varying-constrained DACMG (TVC-DACMG) scheme. The scheme includes the kinematic motion equations of two arms and the time-varying joint limits. The scheme can not only generate the cyclic motion of two arms for a humanoid robot but also control the arms to move to the desired position. In addition, the scheme considers the physical limit avoidance. To solve the QP problem, a recurrent neural network is presented and used to obtain the optimal solutions. Computer simulations and physical experiments demonstrate the effectiveness and the accuracy of such a TVC-DACMG scheme and the neural network solver.

  12. Distributed Task Rescheduling With Time Constraints for the Optimization of Total Task Allocations in a Multirobot System.

    Science.gov (United States)

    Turner, Joanna; Meng, Qinggang; Schaefer, Gerald; Whitbrook, Amanda; Soltoggio, Andrea

    2017-09-28

    This paper considers the problem of maximizing the number of task allocations in a distributed multirobot system under strict time constraints, where other optimization objectives need also be considered. It builds upon existing distributed task allocation algorithms, extending them with a novel method for maximizing the number of task assignments. The fundamental idea is that a task assignment to a robot has a high cost if its reassignment to another robot creates a feasible time slot for unallocated tasks. Multiple reassignments among networked robots may be required to create a feasible time slot and an upper limit to this number of reassignments can be adjusted according to performance requirements. A simulated rescue scenario with task deadlines and fuel limits is used to demonstrate the performance of the proposed method compared with existing methods, the consensus-based bundle algorithm and the performance impact (PI) algorithm. Starting from existing (PI-generated) solutions, results show up to a 20% increase in task allocations using the proposed method.

  13. Hard times, hard choices: founding bioethics today.

    Science.gov (United States)

    Gracia, Diego

    1995-07-01

    The discussions of these past twenty years have significantly improved our knowledge about the foundation of bioethics and the meaning of the four bioethical principles with concern to at least three different points: that they are organised hierarchically, and therefore not "prima facie" of the same level; that they have exceptions, and consequently lack of absolute character; and that they are neither strictly deontological nor purely teleological. The only absolute principle of moral life can be the abstract and unconcrete respect of human beings. But when determining the material content of this respect, principles become contingent and relative. Therefore, moral reasoning must have necessarily no less than three moments, one absolute but merely formal, namely respect for all human beings, and the other two relative and material. The first material moment is comprised of the four bioethical principles, divided into two levels, one private, including the principles of autonomy and beneficence, and the other one public, including those of nonmaleficence and justice. The second material moment deals with specific cases, and requires analysis of their context, including their circumstances and consequences. Only when following these steps, and therefore balancing principlism and contextualism, can moral reasoning be correct and complete.

  14. Effect of time from harvest to agglomeration process of herbaceous mass on the density and hardness of briquettes

    Directory of Open Access Journals (Sweden)

    Marek Rynkiewicz

    2013-01-01

    Full Text Available The study presents the results about the density and hardness of the briquettes produced from barley straw, wheat and rapeseed straw and hay. 6-month and 18-month raw materials after harvest from the fields were used to the agglomeration, stored in stacks in the field. The study showed that the briquettes produced from 6-month material characterized by a greater density in the comparison with the 18-month material. The difference was 130.28 kg·m−3 for the hay briquette, whereas the difference was 58.14 kg·m−3 in the case of rape straw briquettes. Similar results were found for the hardness. All samples of briquette used for testing had longitudinal cracks, however transversal cracks were observed only on the briquettes produced from barley straw and hay.

  15. Recognizing the Repeatable Configurations of Time-Reversible Generalized Langton’s Ant Is PSPACE-Hard

    Directory of Open Access Journals (Sweden)

    Takeo Hagiwara

    2011-01-01

    Full Text Available Chris Langton proposed a model of an artificial life that he named “ant”: an agent- called ant- that is over a square of a grid moves by turning to the left (or right accordingly to black (or white color of the square where it is heading, and the square then reverses its color. Bunimovich and Troubetzkoy proved that an ant’s trajectory is always unbounded, or equivalently, there exists no repeatable configuration of the ant’s system. On the other hand, by introducing a new type of color where the ant goes straight ahead and the color never changes, repeatable configurations are known to exist. In this paper, we prove that determining whether a given finite configuration of generalized Langton’s ant is repeatable or not is PSPACE-hard. We also prove the PSPACE-hardness of the ant’s problem on a hexagonal grid.

  16. A question of time: the land snail Murella muralis (Gastropoda: Pulmonata) reveals constraints on past ecological speciation.

    Science.gov (United States)

    Fiorentino, V; Manganelli, G; Giusti, F; Tiedemann, R; Ketmaier, V

    2013-01-01

    The lively debate about speciation currently focuses on the relative importance of factors driving population differentiation. While many studies are increasingly producing results on the importance of selection, little is known about the interaction between drift and selection. Moreover, there is still little knowledge on the spatial-temporal scales at which speciation occurs, that is, arrangement of habitat patches, abruptness of habitat transitions, climate and habitat changes interacting with selective forces. To investigate these questions, we quantified variation on a fine geographical scale analysing morphological (shell) and genetic data sets coupled with environmental data in the land snail Murella muralis, endemic to the Mediterranean island of Sicily. Analysis of a fragment of the mitochondrial DNA cytochrome oxidase I gene (COI) and eight nuclear microsatellite loci showed that genetic variation is highly structured at a very fine spatial scale by local palaeogeographical events and historical population dynamics. Molecular clock estimates, calibrated here specifically for Tyrrhenian land snails, provided a framework of palaeogeographical events responsible for the observed geographical variations and migration routes. Finally, we showed for the first time well-documented lines of evidence of selection in the past, which explains divergence of land snail shell shapes. We suggest that time and palaeogeographical history acted as constraints in the progress along the ecological speciation continuum. Our study shows that testing for correlation among palaeogeography, morphology and genetic data on a fine geographical scale provides information fundamental for a detailed understanding of ecological speciation processes. © 2012 Blackwell Publishing Ltd.

  17. The position of a standard optical computer mouse affects cardiorespiratory responses during the operation of a computer under time constraints

    Directory of Open Access Journals (Sweden)

    Shunji Sako

    2014-08-01

    Full Text Available Objectives: This study investigated the association between task-induced stress and fatigue by examining the cardiovascular responses of subjects using different mouse positions while operating a computer under time constraints. Material and Methods: The study was participated by 16 young, healthy men and examined the use of optical mouse devices affixed to laptop computers. Two mouse positions were investigated: (1 the distal position (DP, in which the subjects place their forearms on the desk accompanied by the abduction and flexion of their shoulder joints, and (2 the proximal position (PP, in which the subjects place only their wrists on the desk without using an armrest. The subjects continued each task for 16 min. We assessed differences in several characteristics according to mouse position, including expired gas values, autonomic nerve activities (based on cardiorespiratory responses, operating efficiencies (based on word counts, and fatigue levels (based on the visual analog scale – VAS. Results: Oxygen consumption (VO2, the ratio of inspiration time to respiration time (Ti/Ttotal, respiratory rate (RR, minute ventilation (VE, and the ratio of expiration to inspiration (Te/Ti were significantly lower when the participants were performing the task in the DP than those obtained in the PP. Tidal volume (VT, carbon dioxide output rates (VCO2/VE, and oxygen extraction fractions (VO2/VE were significantly higher for the DP than they were for the PP. No significant difference in VAS was observed between the positions; however, as the task progressed, autonomic nerve activities were lower and operating efficiencies were significantly higher for the DP than they were for the PP. Conclusions: Our results suggest that the DP has fewer effects on cardiorespiratory functions, causes lower levels of sympathetic nerve activity and mental stress, and produces a higher total workload than the PP. This suggests that the DP is preferable to the PP when

  18. New Constraints from the Seychelles on the Timing and Magnitude of Peak Global Mean Sea Level during the Last Interglacial

    Science.gov (United States)

    Vyverberg, K.; Dechnik, B.; Dutton, A.; Webster, J.; Zwartz, D.; Edwards, R. L.

    2016-12-01

    Projecting the rate of future sea-level rise remains a primary challenge associated with continued climate change. However, uncertainties remain in our understanding of the rate of polar ice sheet retreat in warmer-than-present climates. To address this issue, we present a new sea level reconstruction from the tectonically stable granitic Seychelles based on Last Interglacial coral ages and elevations within their sedimentary and stratigraphic context, including estimates of paleo-water depth based on newly defined coralgal assemblages. The reef facies analyzed here has a narrow and shallow paleowater depth range (macro facies and stratigraphic analysis reveals a sea-level rise over 5-6 thousand years that is punctuated by repeated episodes of reef disturbance. These episodes are marked stratigraphically by coral rubble layers or extensive lateral encrustations of Millepora sp. that are infested with coral-dwelling barnacles. These disturbance layers may have been generated through internal reef processes and/or external agents, including coral disease, bleaching, predation, hurricanes, or sub-aerial exposure. In total, these new observations provide improved constraints on the timing, magnitude, and rates of sea-level rise during the Last Interglacial.

  19. Modeling Non-Equilibrium Dynamics of a Discrete Probability Distribution: General Rate Equation for Maximal Entropy Generation in a Maximum-Entropy Landscape with Time-Dependent Constraints

    Directory of Open Access Journals (Sweden)

    Gian Paolo Beretta

    2008-08-01

    Full Text Available A rate equation for a discrete probability distribution is discussed as a route to describe smooth relaxation towards the maximum entropy distribution compatible at all times with one or more linear constraints. The resulting dynamics follows the path of steepest entropy ascent compatible with the constraints. The rate equation is consistent with the Onsager theorem of reciprocity and the fluctuation-dissipation theorem. The mathematical formalism was originally developed to obtain a quantum theoretical unification of mechanics and thermodinamics. It is presented here in a general, non-quantal formulation as a part of an effort to develop tools for the phenomenological treatment of non-equilibrium problems with applications in engineering, biology, sociology, and economics. The rate equation is also extended to include the case of assigned time-dependences of the constraints and the entropy, such as for modeling non-equilibrium energy and entropy exchanges.

  20. A New Method for Time-Jerk Optimal Trajectory Planning Under Kino-dynamic Constraint of Robot Manipulators in Pick-and-Place Operations

    Directory of Open Access Journals (Sweden)

    Bendali Nadir

    2014-05-01

    Full Text Available A new method for time-jerk optimal planning under Kino-dynamic constraints of robot manipulators in pick-and-place operations is described in this paper. In order to ensure that the resulting trajectory is smooth enough, a cost function containing a term proportional to the integral of the squared jerk (defined as the derivative of the acceleration along the trajectory is considered. Moreover, a second term, proportional to the total execution time, is added to the expression of the cost function. A Cubic Spline functions are then used to compose overall trajectory. This method makes it possible to deal with the kinematic constraints as well as the dynamic constraints imposed on the robot manipulator. The algorithm has been tested in simulation yielding good results.

  1. A new approach for solution of vehicle routing problem with hard ...

    Indian Academy of Sciences (India)

    ... sometimes impossible if number of constraints is large enough (i.e., NP-hard), and solution time of a VRPHTW grows exponentially. As the size of the problem grows, a near optimal solution can be found using a heuristic method. A hierarchical approach consisting of two stages as. ''cluster-first route-second'' is proposed.

  2. Effects of curing protocol and storage time on the micro-hardness of resin cements used to lute fiber-reinforced resin posts

    Science.gov (United States)

    RAMOS, Marcelo Barbosa; PEGORARO, Thiago Amadei; PEGORARO, Luiz Fernando; CARVALHO, Ricardo Marins

    2012-01-01

    Objectives To determine the micro-hardness profile of two dual cure resin cements (RelyX - U100®, 3M-ESPE and Panavia F 2.0®, Kuraray) used for cementing fiber-reinforced resin posts (Fibrekor® - Jeneric Pentron) under three different curing protocols and two water storage times. Material and methods Sixty 16mm long bovine incisor roots were endodontically treated and prepared for cementation of the Fibrekor posts. The cements were mixed as instructed, dispensed in the canal, the posts were seated and the curing performed as follows: a) no light activation; b) light-activation immediately after seating the post, and; c) light-activation delayed 5 minutes after seating the post. The teeth were stored in water and retrieved for analysis after 7 days and 3 months. The roots were longitudinally sectioned and the microhardness was determined at the cervical, middle and apical regions along the cement line. The data was analyzed by the three-way ANOVA test (curing mode, storage time and thirds) for each cement. The Tukey test was used for the post-hoc analysis. Results Light-activation resulted in a significant increase in the microhardness. This was more evident for the cervical region and for the Panavia cement. Storage in water for 3 months caused a reduction of the micro-hardness for both cements. The U100 cement showed less variation in the micro-hardness regardless of the curing protocol and storage time. Conclusions The micro-hardness of the cements was affected by the curing and storage variables and were material-dependent. PMID:23138743

  3. Effects of curing protocol and storage time on the micro-hardness of resin cements used to lute fiber-reinforced resin posts

    Directory of Open Access Journals (Sweden)

    Marcelo Barbosa Ramos

    2012-10-01

    Full Text Available OBJECTIVES: To determine the micro-hardness profile of two dual cure resin cements (RelyX - U100®, 3M-eSPe and Panavia F 2.0®, Kuraray used for cementing fiberreinforced resin posts (Fibrekor® - Jeneric Pentron under three different curing protocols and two water storage times. MATERIAL AND METHODS: Sixty 16mm long bovine incisor roots were endodontically treated and prepared for cementation of the Fibrekor posts. The cements were mixed as instructed, dispensed in the canal, the posts were seated and the curing performed as follows: a no light activation; b light-activation immediately after seating the post, and; c light-activation delayed 5 minutes after seating the post. The teeth were stored in water and retrieved for analysis after 7 days and 3 months. The roots were longitudinally sectioned and the microhardness was determined at the cervical, middle and apical regions along the cement line. The data was analyzed by the three-way ANOVA test (curing mode, storage time and thirds for each cement. The Tukey test was used for the post-hoc analysis. RESULTS: Light-activation resulted in a significant increase in the microhardness. This was more evident for the cervical region and for the Panavia cement. Storage in water for 3 months caused a reduction of the micro-hardness for both cements. The U100 cement showed less variation in the micro-hardness regardless of the curing protocol and storage time. CONCLUSIONS: The micro-hardness of the cements was affected by the curing and storage variables and were material-dependent.

  4. Ant colony optimization and constraint programming

    CERN Document Server

    Solnon, Christine

    2013-01-01

    Ant colony optimization is a metaheuristic which has been successfully applied to a wide range of combinatorial optimization problems. The author describes this metaheuristic and studies its efficiency for solving some hard combinatorial problems, with a specific focus on constraint programming. The text is organized into three parts. The first part introduces constraint programming, which provides high level features to declaratively model problems by means of constraints. It describes the main existing approaches for solving constraint satisfaction problems, including complete tree search

  5. Early effect of vomerine flap closure of the hard palate at the time of lip repair on the alveolar gap and other maxillary dimensions.

    Science.gov (United States)

    Maggiulli, Federica; Hay, Norman; Mars, Michael; Worrell, Emma; Green, James; Sommerlad, Brian

    2014-01-01

    Comparison of the effects of vomerine flap (VF) closure of the hard palate at the time of lip repair with non-closure of the hard palate in subjects with unilateral cleft lip and palate (UCLP). Retrospective, single-blinded, cohort study. Study model sets of 40 consecutive, non-syndromic, infants with complete UCLP operated on between 1988 and 1998. All subjects were operated on by a single consultant plastic surgeon immediately before and after the unit's change of protocol (1993), when VF closure of the hard palate was incorporated at the time of lip repair. Subjects were divided into two groups: VF ( n = 18) and non-VF (n = 22), which acted as a control group. Each subject had maxillary impressions taken before lip repair at 3 months (VF mean age = 11.7 weeks; non-VF mean age = 13.4 weeks) and before palate repair at 6 months (VF mean age = 22.8 weeks; non-VF mean age = 24.0 weeks). Seven predetermined landmarks and four maxillary dimensions were computed following single-blinded analysis using a reflex microscope. Repeatability tests showed good measurement precision. The operator measurement errors were 0.00018 mm in a horizontal plane (X and Y) and 0.00028 in the vertical plane (Z). The VF group showed significant changes in the alveolar cleft width. There were no statistically significant changes in any arch-form variable between the VF and non-VF groups. The decrease of alveolar arch gap width at palate repair (6 months) in the VF group was significantly more than the decrease observed in the non-VF group, and there was no significant decrease in the, anterior and posterior arch width or anteroposterior length of the hard palate in the VF group compared with the non-VF group.

  6. In search of methods enhancing fluency in reading: An examination of the relations between time constraints and processes of reading in readers of German.

    Science.gov (United States)

    Bar-Kochva, Irit; Hasselhorn, Marcus

    2015-12-01

    The attainment of fluency in reading is a major difficulty for reading-disabled people. Manipulations applied on the presentation of texts, leading to "on-line" effects on reading (i.e., while texts are manipulated), are one direction of examinations in search of methods affecting reading. The imposing of time constraints, by deleting one letter after the other from texts presented on a computer screen, has been established as such a method. In an attempt to further understand its nature, we tested the relations between time constraints and processes of reading: phonological decoding of small orthogrpahic units and the addressing of orthographic representations from the mental lexicon. We also examined whether the type of orthogrpahic unit deleted (lexical, sublexical, or nonlexical unit) has any additional effect. Participants were German fifth graders with (n = 29) or without (n = 34) reading disability. Time constraints enhanced fluency in reading in both groups, and to a similar extent, across conditions. Comprehension was unimpaired. These results place the very principle of time constraints, regardless of the orthographic unit manipulated, as a critical factor affecting fluency in reading. However, phonological decoding explained a significant amount of variance in fluency in reading across all conditions in reading-disabled children, whereas the addressing of orthographic representations was the consistent predictor of fluency in reading in regular readers. These results indicate a qualitative difference in the processes explaining the variance in fluency in reading in regular and reading-disabled readers and suggest that time constraints might not have an effect on the relations between these processes and reading performance. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Effect of casein phosphopeptide-amorphous calcium phosphate (cpp-acp on caries-like lesions in terms of time and nano-hardness: An in vitro study

    Directory of Open Access Journals (Sweden)

    Shanthan Mettu

    2015-01-01

    Full Text Available Context: Time bound increase in the nanohardness of the enamel after remineralization with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP in a regular interval of 1 h has not been explored in the literature to a greater extent. Aims: To determine and compare the maximum hardness of the remineralized caries-like lesions, in terms of nanohardness and the rate of achieving maximum hardness at 1-h interval, after treatment with artificial saliva and CPP-ACP, over 12 h. Materials and Methods: Fifty longitudinal sections of extracted sound permanent maxillary central, lateral incisors were immersed in demineralizing solution for 4 days. The samples were then randomly divided into three groups, consisting of 12 sections each for soaking them in three different media-isotonic saline, artificial saliva, and CPP-ACP for 12 h. The nanohardness was measured on the labial surface, at baseline, after erosion, and after remineralization at 1-h interval. Statistical Analysis Used: The data was analyzed with paired t-test, one-way analysis of variance (ANOVA and post-hoc analysis. Results: CPP-ACP increased the enamel hardness significantly (P < 0.001, at an increased rate, than artificial saliva. Conclusions: This study has provided an insight into the frequency of use of CPP-ACP, once per day, as the nanohardness of enamel samples increased within 1 h of application and remained within the normal limits after 12 h.

  8. Time constraints on the evolution of southern Palawan Island, Philippines from onshore and offshore correlation of Miocene limestones

    Science.gov (United States)

    Steuer, Stephan; Franke, Dieter; Meresse, Florian; Savva, Dimitri; Pubellier, Manuel; Auxietre, Jean-Luc; Aurelio, Mario

    2013-10-01

    underwent a phase of subsidence. Based upon the detailed correlation of these limestones we propose that the wedge did not form in the southern Palawan area prior to ˜18 Ma. Using the sealing Tabon limestone as time constraint we suggest that the development of the wedge in the south Palawan area started in the lower Middle Miocene (˜15 Ma) and continued developing towards the west until the upper Late Miocene to Early Pliocene (˜5 Ma). After the wedge propagation stopped, the wedge front collapsed in several places due to gravitational sliding. Southern and central Palawan were uplifted above sea level during a second phase of compression in the Late Pliocene. Onshore outcrops give indications to a working spleothem since ˜1.2 Ma.

  9. Radiofrequency pulse design in parallel transmission under strict temperature constraints.

    Science.gov (United States)

    Boulant, Nicolas; Massire, Aurélien; Amadon, Alexis; Vignaud, Alexandre

    2014-09-01

    To gain radiofrequency (RF) pulse performance by directly addressing the temperature constraints, as opposed to the specific absorption rate (SAR) constraints, in parallel transmission at ultra-high field. The magnitude least-squares RF pulse design problem under hard SAR constraints was solved repeatedly by using the virtual observation points and an active-set algorithm. The SAR constraints were updated at each iteration based on the result of a thermal simulation. The numerical study was performed for an SAR-demanding and simplified time of flight sequence using B1 and ΔB0 maps obtained in vivo on a human brain at 7T. The proposed adjustment of the SAR constraints combined with an active-set algorithm provided higher flexibility in RF pulse design within a reasonable time. The modifications of those constraints acted directly upon the thermal response as desired. Although further confidence in the thermal models is needed, this study shows that RF pulse design under strict temperature constraints is within reach, allowing better RF pulse performance and faster acquisitions at ultra-high fields at the cost of higher sequence complexity. Copyright © 2013 Wiley Periodicals, Inc.

  10. Influence of timing of delayed hard palate closure on articulation skills in 3-year-old Danish children with unilateral cleft lip and palate.

    Science.gov (United States)

    Willadsen, Elisabeth; Boers, Maria; Schöps, Antje; Kisling-Møller, Mia; Nielsen, Joan Bogh; Jørgensen, Line Dahl; Andersen, Mikael; Bolund, Stig; Andersen, Helene Søgaard

    2017-07-25

    Differing results regarding articulation skills in young children with cleft palate (CP) have been reported and often interpreted as a consequence of different surgical protocols. To assess the influence of different timing of hard palate closure in a two-stage procedure on articulation skills in 3-year-olds born with unilateral cleft lip and palate (UCLP). Secondary aims were to compare results with peers without CP, and to investigate if there are gender differences in articulation skills. Furthermore, burden of treatment was to be estimated in terms of secondary surgery, hearing and speech therapy. A randomized controlled trial (RCT). Early hard palate closure (EHPC) at 12 months versus late hard palate closure (LHPC) at 36 months in a two-stage procedure was tested in a cohort of 126 Danish-speaking children born with non-syndromic UCLP. All participants had the lip and soft palate closed around 4 months of age. Audio and video recordings of a naming test were available from 113 children (32 girls and 81 boys) and were transcribed phonetically. Recordings were obtained prior to hard palate closure in the LHPC group. The main outcome measures were percentage consonants correct adjusted (PCC-A) and consonant errors from blinded assessments. Results from 36 Danish-speaking children without CP obtained previously by Willadsen in 2012 were used for comparison. Children with EHPC produced significantly more target consonants correctly (83%) than children with LHPC (48%; p < .001). In addition, children with LHPC produced significantly more active cleft speech characteristics than children with EHPC (p < .001). Boys achieved significantly lower PCC-A scores than girls (p = .04) and produced significantly more consonant errors than girls (p = .02). No significant differences were found between groups regarding burden of treatment. The control group performed significantly better than the EHPC and LHPC groups on all compared variables. © 2017 Royal College of Speech

  11. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...

  12. Standard hardness conversion tables for metals relationship among brinell hardness, vickers hardness, rockwell hardness, superficial hardness, knoop hardness, and scleroscope hardness

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 Conversion Table 1 presents data in the Rockwell C hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.2 Conversion Table 2 presents data in the Rockwell B hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.3 Conversion Table 3 presents data on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, and Knoop hardness of nickel and high-nickel alloys (nickel content o...

  13. Efficient constraint-based Sequential Pattern Mining (SPM algorithm to understand customers’ buying behaviour from time stamp-based sequence dataset

    Directory of Open Access Journals (Sweden)

    Niti Ashish Kumar Desai

    2015-12-01

    Full Text Available Business Strategies are formulated based on an understanding of customer needs. This requires development of a strategy to understand customer behaviour and buying patterns, both current and future. This involves understanding, first how an organization currently understands customer needs and second predicting future trends to drive growth. This article focuses on purchase trend of customer, where timing of purchase is more important than association of item to be purchased, and which can be found out with Sequential Pattern Mining (SPM methods. Conventional SPM algorithms worked purely on frequency identifying patterns that were more frequent but suffering from challenges like generation of huge number of uninteresting patterns, lack of user’s interested patterns, rare item problem, etc. Article attempts a solution through development of a SPM algorithm based on various constraints like Gap, Compactness, Item, Recency, Profitability and Length along with Frequency constraint. Incorporation of six additional constraints is as well to ensure that all patterns are recently active (Recency, active for certain time span (Compactness, profitable and indicative of next timeline for purchase (Length―Item―Gap. The article also attempts to throw light on how proposed Constraint-based Prefix Span algorithm is helpful to understand buying behaviour of customer which is in formative stage.

  14. "Wood already touched by fire is not hard to set alight": Comment on "Constraints to applying systems thinking concepts in health systems: A regional perspective from surveying stakeholders in Eastern Mediterranean countries".

    Science.gov (United States)

    Agyepong, Irene Akua

    2015-03-01

    A major constraint to the application of any form of knowledge and principles is the awareness, understanding and acceptance of the knowledge and principles. Systems Thinking (ST) is a way of understanding and thinking about the nature of health systems and how to make and implement decisions within health systems to maximize desired and minimize undesired effects. A major constraint to applying ST within health systems in Low- and Middle-Income Countries (LMICs) would appear to be an awareness and understanding of ST and how to apply it. This is a fundamental constraint and in the increasing desire to enable the application of ST concepts in health systems in LMIC and understand and evaluate the effects; an essential first step is going to be enabling of a wide spread as well as deeper understanding of ST and how to apply this understanding.

  15. CONSTRAINT PROGRAMMING AND UNIVERSITY TIMETABLING

    Directory of Open Access Journals (Sweden)

    G.W. Groves

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: The technology of Constraint Programming is rapidly becoming a popular alternative for solving large-scale industry problems. This paper provides an introduction to Constraint Programming and to Constraint Logic Programming (CLP, an enabler of constraint programming. The use of Constraint Logic Programming is demonstrated by describing a system developed for scheduling university timetables. Timetabling problems have a high degree of algorithmic complexity (they are usually NP-Complete, and share features with scheduling problems encountered in industry. The system allows the declaration of both hard requirements, which must always be satisfied, and soft constraints which need not be satisfied, though this would be an advantage.

    AFRIKAANSE OPSOMMING: Hierdie artikel beskryf ’n familie van probleem-oplossingstegnieke bekend as “Constraint Programming”, wat al hoe meer gebruik word om groot-skaalse industriële probleme op te los. Die nut van hierdie tegnieke word gedemonstreer deur die beskrywing van ’n skeduleringsisteem om die roosters vir ’n universiteit te genereer. Roosterskeduleringsprobleme is in praktiese gevalle NP-volledig en deel baie eienskappe met industriële skeduleringsprobleme. Die sisteem wat hier beskryf word maak gebruik van beide harde beperkings (wat altyd bevredig moet word en sagte beperkings (bevrediging hiervan is wel voordelig maar dit is opsioneel.

  16. Kalman Filtering with Inequality Constraints for Turbofan Engine Health Estimation

    Science.gov (United States)

    Simon, Dan; Simon, Donald L.

    2003-01-01

    Kalman filters are often used to estimate the state variables of a dynamic system. However, in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints (which may be based on physical considerations) are often neglected because they do not fit easily into the structure of the Kalman filter. This paper develops two analytic methods of incorporating state variable inequality constraints in the Kalman filter. The first method is a general technique of using hard constraints to enforce inequalities on the state variable estimates. The resultant filter is a combination of a standard Kalman filter and a quadratic programming problem. The second method uses soft constraints to estimate state variables that are known to vary slowly with time. (Soft constraints are constraints that are required to be approximately satisfied rather than exactly satisfied.) The incorporation of state variable constraints increases the computational effort of the filter but significantly improves its estimation accuracy. The improvement is proven theoretically and shown via simulation results. The use of the algorithm is demonstrated on a linearized simulation of a turbofan engine to estimate health parameters. The turbofan engine model contains 16 state variables, 12 measurements, and 8 component health parameters. It is shown that the new algorithms provide improved performance in this example over unconstrained Kalman filtering.

  17. Maximizing the Total Weight of Just-In-Time Jobs under Multi-Slot Conditions Is NP-Hard

    National Research Council Canada - National Science Library

    CHIBA, Eishi; IMAHORI, Shinji

    2016-01-01

    A job is called just-in-time if it is completed exactly on its due date. Under multi-slot conditions, each job has one due date per time slot and has to be completed just-in-time on one of its due dates...

  18. Economic Design of Multi-echelon Inventory System with Variable Lead Time and Service Level Constraint in a Fuzzy Cost Environment

    OpenAIRE

    S. Priyan; R. Uthayakumar

    2016-01-01

    Normally, human based industrial decision making involves both quantitative and qualitative input factors such as ordering cost, setup cost, etc. Thus the practitioners should be careful in accounting flexibility in the input factors. This paper optimizes an inventory system by employing mathematical model with variable lead time and service level constraint (SLC) in a fuzzy cost environment. Fuzziness is established by allowing the cost components imprecise and vague to certain extent. Trape...

  19. Hard real-time quick EXAFS data acquisition with all open source software on a commodity personal computer

    Science.gov (United States)

    So, I.; Siddons, D. P.; Caliebe, W. A.; Khalid, S.

    2007-11-01

    We describe here the data acquisition subsystem of the Quick EXAFS (QEXAFS) experiment at the National Synchrotron Light Source of Brookhaven National Laboratory. For ease of future growth and flexibility, almost all software components are open source with very active maintainers. Among them, Linux running on x86 desktop computer, RTAI for real-time response, COMEDI driver for the data acquisition hardware, Qt and PyQt for graphical user interface, PyQwt for plotting, and Python for scripting. The signal (A/D) and energy-reading (IK220 encoder) devices in the PCI computer are also EPICS enabled. The control system scans the monochromator energy through a networked EPICS motor. With the real-time kernel, the system is capable of deterministic data-sampling period of tens of micro-seconds with typical timing-jitter of several micro-seconds. At the same time, Linux is running in other non-real-time processes handling the user-interface. A modern Qt-based controls-frontend enhances productivity. The fast plotting and zooming of data in time or energy coordinates let the experimenters verify the quality of the data before detailed analysis. Python scripting is built-in for automation. The typical data-rate for continuous runs are around 10 M bytes/min.

  20. Influence of capacity- and time-constrained intermediate storage in two-stage food production systems

    DEFF Research Database (Denmark)

    Akkerman, Renzo; van Donk, Dirk Pieter; Gaalman, Gerard

    2007-01-01

    In food processing, two-stage production systems with a batch processor in the first stage and packaging lines in the second stage are common and mostly separated by capacity- and time-constrained intermediate storage. This combination of constraints is common in practice, but the literature hard...... is dictated by the storage time constraint....

  1. A beam branching method for timing and spectral characterization of hard X-ray free-electron lasers

    Directory of Open Access Journals (Sweden)

    Tetsuo Katayama

    2016-05-01

    Full Text Available We report a method for achieving advanced photon diagnostics of x-ray free-electron lasers (XFELs under a quasi-noninvasive condition by using a beam-splitting scheme. Here, we used a transmission grating to generate multiple branches of x-ray beams. One of the two primary diffracted branches (+1st-order is utilized for spectral measurement in a dispersive scheme, while the other (−1st-order is dedicated for arrival timing diagnostics between the XFEL and the optical laser pulses. The transmitted x-ray beam (0th-order is guided to an experimental station. To confirm the validity of this timing-monitoring scheme, we measured the correlation between the arrival timings of the −1st and 0th branches. The observed error was as small as 7.0 fs in root-mean-square. Our result showed the applicability of the beam branching scheme to advanced photon diagnostics, which will further enhance experimental capabilities of XFEL.

  2. Influence of timing of hard palate repair in a two-stage procedure on early language development in Danish children with cleft palate

    DEFF Research Database (Denmark)

    Willadsen, Elisabeth

    2012-01-01

    vocalizations, consonants, and consonants permissible in word-initial position than the Early HPR group. In addition, both cleft palate groups had a smaller productive vocabulary than the Control group, but unlike the EarlyHPR group, the LateHPU group produced a smaller number of word tokens in social...... were transcribed according to the International Phonetic Alphabet. At 36 months a single word naming test was administered. Results: at 18 months, the LateHPU group produced fewer labial stops and more velar stops than the Early HPR group. Unlike the Early HPR group, the LateHPU group produced fewer...... interaction than the Control group. By 3 years of age, the LateHPU group had a (severely) restricted phonological system and produced more cleft speech characteristics than the EarlyHPR group. Conclusions: surgical timing of hard palate repair in a two-stage procedure appears to have an influence on early...

  3. Real-time guidance of thermal and ultrashort pulsed laser ablation in hard tissue using inline coherent imaging.

    Science.gov (United States)

    Leung, Ben Y C; Webster, Paul J L; Fraser, James M; Yang, Victor X D

    2012-03-01

    During tissue ablation, laser light can be delivered with high precision in the transverse dimensions but final incision depth can be difficult to control. We monitor incision depth as it progresses, providing feedback to ensure that material removal occurs within a localized target volume, reducing the possibility of undesirable damage to tissues below the incision. Ex vivo cortical and cancellous bone was ablated using pulsed lasers with center wavelengths of 1,064 and 1,070 nm, while being imaged in real-time using inline coherent imaging (ICI) at rates of up to 300 kHz and axial resolution of ∼6 µm. With real-time feedback, laser exposure was terminated before perforating into natural inclusions of the cancellous bone and verified by brightfield microscopy of the crater cross-sections accessed via side-polishing. ICI provides direct information about incision penetration even in the presence of intense backscatter from the pulsed laser and plasma emissions. In this study, ICI is able to anticipate structures 176 ± 8 µm below the ablation front with signal intensity 9 ± 2 dB above the noise floor. As a result, the operator is able to terminate exposure of the laser sparing a 50 µm thick layer of bone between the bottom of the incision to a natural inclusion in the cancellous bone. Versatility of the ICI system was demonstrated over a wide range of light-tissue interactions from thermal regime to direct solid-plasma transition. ICI can be used as non-contact real-time feedback to monitor the depth of an incision created by laser ablation, especially in heterogeneous tissue where ablation rate is less predictable. Furthermore, ICI can image below the ablation front making it possible to stop laser exposure to limit unintentional damage to subsurface structures such as blood vessels or nervous tissue. Copyright © 2012 Wiley Periodicals, Inc.

  4. Hard times and European youth. The effect of economic insecurity on human values, social attitudes and well-being.

    Science.gov (United States)

    Reeskens, Tim; Vandecasteele, Leen

    2017-02-01

    While economic downturns have adverse effects on young people's life chances, empirical studies examining whether and to what extent human values, social attitudes and well-being indicators respond to sudden economic shocks are scarce. To assess the claim that human values are less affected by economic shocks than social attitudes and well-being, two distinct yet related studies based on the European Social Survey (ESS) are conducted. The first employs a fixed effects pseudo-panel analysis of the 2008-2014 ESS-waves to detect whether changes over time in the socio-demographic group's unemployment risk and national youth unemployment affect individual dispositions to varying degrees. The second study captures micro- and cross-national effects in the 2010 ESS cross-section. Unique for this set-up is that we can test whether the findings hold for over-time changes in youth unemployment within countries (pseudo-panel), as well as for cross-country differences in youth unemployment (multilevel). Both studies indicate that political trust, satisfaction with the economy and subjective well-being are lowered by economic risk and hardship, while social trust and self-rated health are less affected by changes in youth unemployment. Secondly, human values are immune to economic risk, underscoring that values transcend specific situations and are therefore resistant against sudden economic shocks. © 2016 The Authors. International Journal of Psychology published by John Wiley & Sons Ltd on behalf of International Union of Psychological Science.

  5. Airway and hard tissue dimensions in children treated with early and later timed cervical headgear-a randomized controlled trial.

    Science.gov (United States)

    Julku, Johanna; Pirilä-Parkkinen, Kirsi; Pirttiniemi, Pertti

    2017-12-08

    A Kloehn-type cervical headgear (CH) aims to correct skeletal jaw discrepancy in Class II children. A few studies have reported CH treatment effects on airway dimensions, but none of them have been randomized according to timing. To evaluate related craniofacial structures and pharyngeal airway dimensions in children with a Class II occlusion treated with CH and randomized into early and late treatment groups. Randomized, parallel-group, prospective controlled trial. The material comprised 67 seven-year-old children with a Class II occlusion. Sealed-envelope randomization in 1:1 ratio was used to divide the children into two equal groups. In the early group (EG, n = 33), CH treatment was started immediately or after eruption of the first maxillary molars. In the second, late group (LG, n = 34), the active CH treatment was started about one and half year later. The active CH treatment was continued in both groups until normal Class I occlusion on first molars was achieved. Cephalometric radiographs were taken from both groups at the beginning of follow-up (T0), at the beginning of CH treatment of the second group (T1), and at the end of CH treatment of the second group (T2). Changes in cephalometric measurements were used as primary outcomes. Blinding was applicable for outcome assessment. Fifty-six children completed the study. The posterior change in the position of the maxilla was significant for early treatment males at T0-T1 (SNA; P < 0.001, ANB; P = 0.009) and T0-T2 (SNA; P = 0.012). The palato-mandibular angle (PL-ML) decreased during T0-T1 in early treatment females (P = 0.018) and early treatment males (P = 0.037). The retroglossal airway increased (P = 0.010) in early treatment males at T0-T1. Highly significant positive correlations (P < 0.001) between skeletal and upper airway dimensions during early CH treatment were found in males. No harms were encountered. Despite the effective CH treatment, no harmful upper airway changes were found. NCT02010346.

  6. Sequence polymorphism can produce serious artefacts in real-time PCR assays: hard lessons from Pacific oysters

    Directory of Open Access Journals (Sweden)

    Camara Mark D

    2008-05-01

    Full Text Available Abstract Background Since it was first described in the mid-1990s, quantitative real time PCR (Q-PCR has been widely used in many fields of biomedical research and molecular diagnostics. This method is routinely used to validate whole transcriptome analyses such as DNA microarrays, suppressive subtractive hybridization (SSH or differential display techniques such as cDNA-AFLP (Amplification Fragment Length Polymorphism. Despite efforts to optimize the methodology, misleading results are still possible, even when standard optimization approaches are followed. Results As part of a larger project aimed at elucidating transcriptome-level responses of Pacific oysters (Crassostrea gigas to various environmental stressors, we used microarrays and cDNA-AFLP to identify Expressed Sequence Tag (EST fragments that are differentially expressed in response to bacterial challenge in two heat shock tolerant and two heat shock sensitive full-sib oyster families. We then designed primers for these differentially expressed ESTs in order to validate the results using Q-PCR. For two of these ESTs we tested fourteen primer pairs each and using standard optimization methods (i.e. melt-curve analysis to ensure amplification of a single product, determined that of the fourteen primer pairs tested, six and nine pairs respectively amplified a single product and were thus acceptable for further testing. However, when we used these primers, we obtained different statistical outcomes among primer pairs, raising unexpected but serious questions about their reliability. We hypothesize that as a consequence of high levels of sequence polymorphism in Pacific oysters, Q-PCR amplification is sub-optimal in some individuals because sequence variants in priming sites results in poor primer binding and amplification in some individuals. This issue is similar to the high frequency of null alleles observed for microsatellite markers in Pacific oysters. Conclusion This study highlights

  7. Influence of timing of delayed hard palate closure on articulation skills in 3-year-old Danish children with unilateral cleft lip and palate

    DEFF Research Database (Denmark)

    Willadsen, Elisabeth; Boers, Maria; Schöps, Antje

    2017-01-01

    , hearing and speech therapy. Methods & Procedures A randomized controlled trial (RCT). Early hard palate closure (EHPC) at 12 months versus late hard palate closure (LHPC) at 36 months in a two-stage procedure was tested in a cohort of 126 Danish-speaking children born with non-syndromic UCLP. All...

  8. Influence of timing of delayed hard palate closure on articulation skills in 3-year-old Danish children with unilateral cleft lip and palate

    DEFF Research Database (Denmark)

    Willadsen, Elisabeth; Boers, Maria; Schöps, Antje

    2018-01-01

    , hearing and speech therapy. METHODS & PROCEDURES: A randomized controlled trial (RCT). Early hard palate closure (EHPC) at 12 months versus late hard palate closure (LHPC) at 36 months in a two-stage procedure was tested in a cohort of 126 Danish-speaking children born with non-syndromic UCLP. All...

  9. Formal Constraints on Memory Management for Composite Overloaded Operations

    Directory of Open Access Journals (Sweden)

    Damian W.I. Rouson

    2006-01-01

    Full Text Available The memory management rules for abstract data type calculus presented by Rouson, Morris & Xu [15] are recast as formal statements in the Object Constraint Language (OCL and applied to the design of a thermal energy equation solver. One set of constraints eliminates memory leaks observed in composite overloaded expressions with three current Fortran 95/2003 compilers. A second set of constraints ensures economical memory recycling. The constraints are preconditions, postconditions and invariants on overloaded operators and the objects they receive and return. It is demonstrated that systematic run-time assertion checking inspired by the formal constraints facilitated the pinpointing of an exceptionally hard-to-reproduce compiler bug. It is further demonstrated that the interplay between OCL's modeling capabilities and Fortran's programming capabilities led to a conceptual breakthrough that greatly improved the readability of our code by facilitating operator overloading. The advantages and disadvantages of our memory management rules are discussed in light of other published solutions [11,19]. Finally, it is demonstrated that the run-time assertion checking has a negligible impact on performance.

  10. Using response-time constraints in item selection to control for differential speededness in computerized adaptive testing

    NARCIS (Netherlands)

    van der Linden, Willem J.; Scrams, David J.; Schnipke, Deborah L.

    2003-01-01

    This paper proposes an item selection algorithm that can be used to neutralize the effect of time limits in computer adaptive testing. The method is based on a statistical model for the response-time distributions of the test takers on the items in the pool that is updated each time a new item has

  11. Using response-time Constraints in item selection to control for differential speededness in computerized adaptive testing

    NARCIS (Netherlands)

    van der Linden, Willem J.; Scrams, David J.; Schnipke, Deborah L.

    1998-01-01

    An item-selection algorithm to neutralize the differential effects of time limits on scores on computerized adaptive tests is proposed. The method is based on a statistical model for the response-time distributions of the examinees on items in the pool that is updated each time a new item has been

  12. The effect of time in the exposure of theobromine gel to enamel and surface hardness after demineralization with 1% citric acid

    Science.gov (United States)

    Irawan, M. I. P.; Noerdin, A.; Eriwati, Y. K.

    2017-08-01

    Theobromine is one of the alkaloid compounds that can be found in cacao (Theobroma cacao). It is said that theobromine can prevent enamel demineralization. The aim of this research was to evaluate the effect of different exposure times to 200 mg/L theobromine gel on enamel microhardness after demineralization in 1% citric acid. Twenty-eight specimens of human premolar teeth were divided into four groups and were immersed in 1% citric acid (pH 4) for 2.5 minutes. Then 200 mg/L theobromine gel was exposed to the specimens for 16 minutes (n = 7), 48 minutes (n = 7), and 96 minutes (n = 7). Enamel microhardness (KHN) values were tested using the Knoop Microhardness Tester (Shimadzu, Japan) using a 50-gram load for 5 seconds. A statistical test was performed using the Friedman test, Wilcoxon test, Kruskal-Wallis test, and Mann-Whitney test. The results showed a significant decrease, of microhardness values after demineralization with 1% citric acid. There was also a significant increase in hardness (p<0.05) after exposure of the demineralized specimens to theobromine gel for 16 minutes (32.3%), 48 minutes (39.8%), and 96 minutes (43.7%). It can be concluded that exposure to 200 mg/L theobromine gel for 16, 48, and 96 minutes increased enamel microhardness.

  13. SUPER HARD SURFACED POLYMERS

    Energy Technology Data Exchange (ETDEWEB)

    Mansur, Louis K [ORNL; Bhattacharya, R [UES, Incorporated, Dayton, OH; Blau, Peter Julian [ORNL; Clemons, Art [ORNL; Eberle, Cliff [ORNL; Evans, H B [UES, Incorporated, Dayton, OH; Janke, Christopher James [ORNL; Jolly, Brian C [ORNL; Lee, E H [Consultant, Milpitas, CA; Leonard, Keith J [ORNL; Trejo, Rosa M [ORNL; Rivard, John D [ORNL

    2010-01-01

    High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

  14. The Effect of Bulk Depth and Irradiation Time on the Surface Hardness and Degree of Cure of Bulk-Fill Composites

    Directory of Open Access Journals (Sweden)

    Farahat F

    2016-09-01

    Full Text Available Statement of Problem: For many years, application of the composite restoration with a thickness less than 2 mm for achieving the minimum polymerization contraction and stress has been accepted as a principle. But through the recent development in dental material a group of resin based composites (RBCs called Bulk Fill is introduced whose producers claim the possibility of achieving a good restoration in bulks with depths of 4 or even 5 mm. Objectives: To evaluate the effect of irradiation times and bulk depths on the degree of cure (DC of a bulk fill composite and compare it with the universal type. Materials and Methods: This study was conducted on two groups of dental RBCs including Tetric N Ceram Bulk Fill and Tetric N Ceram Universal. The composite samples were prepared in Teflon moulds with a diameter of 5 mm and height of 2, 4 and 6 mm. Then, half of the samples in each depth were cured from the upper side of the mould for 20s by LED light curing unit. The irradiation time for other specimens was 40s. After 24 hours of storage in distilled water, the microhardness of the top and bottom of the samples was measured using a Future Tech (Japan- Model FM 700 Vickers hardness testing machine. Data were analyzed statistically using the one and multi way ANOVAand Tukey’s test (p = 0.050. Results: The DC of Tetric N Ceram Bulk Fill in defined irradiation time and bulk depth was significantly more than the universal type (p < 0.001. Also, the DC of both composites studied was significantly (p < 0.001 reduced by increasing the bulk depths. Increasing the curing time from 20 to 40 seconds had a marginally significant effect (p ≤ 0.040 on the DC of both bulk fill and universal studied RBC samples. Conclusions: The DC of the investigated bulk fill composite was better than the universal type in all the irradiation times and bulk depths. The studied universal and bulk fill RBCs had an appropriate DC at the 2 and 4 mm bulk depths respectively and

  15. Endothermic decompositions of inorganic monocrystalline thin plates. I. Shape of polycrystalline product domains versus constraints and time

    Science.gov (United States)

    Bertrand, G.; Comperat, M.; Lallemant, M.; Watelle, G.

    1980-03-01

    Copper sulfate pentahydrate dehydration into trihydrate was investigated using monocrystalline platelets with varying crystallographic orientations. The morphological and kinetic features of the trihydrate domains were examined. Different shapes were observed: polygons (parallelograms, hexagons) and ellipses; their conditions of occurrence are reported in the (P, T) diagram. At first (for about 2 min), the ratio of the long to the short axes of elliptical domains changes with time; these subsequently develop homothetically and the rate ratio is then only pressure dependent. Temperature influence is inferred from that of pressure. Polygonal shapes are time dependent and result in ellipses. So far, no model can be put forward. Yet, qualitatively, the polygonal shape of a domain may be explained by the prevalence of the crystal arrangement and the elliptical shape by that of the solid tensorial properties. The influence of those factors might be modulated versus pressure, temperature, interface extent, and, thus, time.

  16. The Manpower Allocation Problem with Time Windows and Job-Teaming Constraints: A Branch-and-Price Approach

    DEFF Research Database (Denmark)

    Hansen, Anders Dohn; Kolind, Esben; Clausen, Jens

    2009-01-01

    . Both teams and tasks may be restricted by time windows outside which operation is not possible. Some tasks require cooperation between teams, and all teams cooperating must initiate execution simultaneously. We present an IP-model for the problem, which is decomposed using Dantzig-Wolfe decomposition...

  17. Surface areas and packing constraints in POPC C (12)EO (n) membranes. A time-resolved fluorescence study

    NARCIS (Netherlands)

    Lantzch, G.; Binder, H.; Heerklotz, H.; Wendling, M.; Klose, G.

    1996-01-01

    The surface area occupied by nonionic detergents of the type C(12)EO(n) (n = 1-8) in POPC C (12)EO (n) mixed membranes was studied by means of time-resolved resonance energy transfer (RET) between the fluorescent probe molecules NBD-PE and rhodamine-PE. The area data were interpreted within the

  18. Quantum information density scaling and qubit operation time constraints of CMOS silicon-based quantum computer architectures

    NARCIS (Netherlands)

    Rotta, Davide; Sebastiano, F.; Charbon, E.E.E.; Prati, Enrico

    2017-01-01

    Even the quantum simulation of an apparently simple molecule such as Fe2S2 requires a considerable number of qubits of the order of 106, while more complex molecules such as alanine (C3H7NO2) require about a hundred times more. In order to assess such a multimillion scale of identical qubits and

  19. Modeling Brand Extension as a Real Option: How Expectation, Competition and Financial Constraints Drive the Timing of Extensions

    NARCIS (Netherlands)

    L.H. Pattikawa

    2006-01-01

    textabstractDespite their strategic importance firm’s motivations to extend brands have received only modest attentions by marketing scholars. We use multiple events duration models to examine the timing of launching brand extensions. We provide a theoretical framework of brand extensions based on

  20. Images, Ideals and Constraints in Times of Neoliberal Transformations: Reproduction and Profession as Conflicting or Complementary Spheres in Academia?

    Science.gov (United States)

    Bomert, Christiane; Leinfellner, Stefanie

    2017-01-01

    The article deals with structural, cultural and habitual concepts, principles and ideals of parenthood in the German academic working context. It focuses on social processes of transformation and reconfiguration of reproduction and profession, which means within work and family spheres and especially within academia in times of neoliberalism,…

  1. Walking, running, and resting under time, distance, and average speed constraints: optimality of walk–run–rest mixtures

    Science.gov (United States)

    Long, Leroy L.; Srinivasan, Manoj

    2013-01-01

    On a treadmill, humans switch from walking to running beyond a characteristic transition speed. Here, we study human choice between walking and running in a more ecological (non-treadmill) setting. We asked subjects to travel a given distance overground in a given allowed time duration. During this task, the subjects carried, and could look at, a stopwatch that counted down to zero. As expected, if the total time available were large, humans walk the whole distance. If the time available were small, humans mostly run. For an intermediate total time, humans often use a mixture of walking at a slow speed and running at a higher speed. With analytical and computational optimization, we show that using a walk–run mixture at intermediate speeds and a walk–rest mixture at the lowest average speeds is predicted by metabolic energy minimization, even with costs for transients—a consequence of non-convex energy curves. Thus, sometimes, steady locomotion may not be energy optimal, and not preferred, even in the absence of fatigue. Assuming similar non-convex energy curves, we conjecture that similar walk–run mixtures may be energetically beneficial to children following a parent and animals on long leashes. Humans and other animals might also benefit energetically from alternating between moving forward and standing still on a slow and sufficiently long treadmill. PMID:23365192

  2. Walking, running, and resting under time, distance, and average speed constraints: optimality of walk-run-rest mixtures.

    Science.gov (United States)

    Long, Leroy L; Srinivasan, Manoj

    2013-04-06

    On a treadmill, humans switch from walking to running beyond a characteristic transition speed. Here, we study human choice between walking and running in a more ecological (non-treadmill) setting. We asked subjects to travel a given distance overground in a given allowed time duration. During this task, the subjects carried, and could look at, a stopwatch that counted down to zero. As expected, if the total time available were large, humans walk the whole distance. If the time available were small, humans mostly run. For an intermediate total time, humans often use a mixture of walking at a slow speed and running at a higher speed. With analytical and computational optimization, we show that using a walk-run mixture at intermediate speeds and a walk-rest mixture at the lowest average speeds is predicted by metabolic energy minimization, even with costs for transients-a consequence of non-convex energy curves. Thus, sometimes, steady locomotion may not be energy optimal, and not preferred, even in the absence of fatigue. Assuming similar non-convex energy curves, we conjecture that similar walk-run mixtures may be energetically beneficial to children following a parent and animals on long leashes. Humans and other animals might also benefit energetically from alternating between moving forward and standing still on a slow and sufficiently long treadmill.

  3. TIME AND ENERGY CONSTRAINTS OF FISHING BEHAVIOR IN BREEDING CORMORANTS PHALACROCORAX-CARBO-SINENSIS AT LAKE IJSSELMEER, THE NETHERLANDS

    NARCIS (Netherlands)

    PLATTEEUW, M; VANEERDEN, MR

    1995-01-01

    TWO Cormorant colonies in The Netherlands (Naardermeer and Oostvaardersplassen), exploiting the same water bodies but situated at different distances from them, were compared with respect to daily variations in exact fishing sites and corresponding variations in time budget and fish consumption.

  4. EARLY-PHASE PHOTOMETRY AND SPECTROSCOPY OF TRANSITIONAL TYPE Ia SN 2012ht: DIRECT CONSTRAINT ON THE RISE TIME

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, Masayuki; Nogami, Daisaku [Kwasan Observatory, Kyoto University, 17-1 Kitakazan-ohmine-cho, Yamashina-ku, Kyoto 607-8471 (Japan); Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Kawabata, Miho; Masumoto, Kazunari; Matsumoto, Katsura [Astronomical Institute, Osaka Kyoiku University, Asahigaoka, Kashiwara, Osaka 582-8582 (Japan); Tanaka, Masaomi [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Takaki, Katsutoshi; Ueno, Issei; Itoh, Ryosuke [Department of Physical Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan); Kawabata, Koji S.; Moritani, Yuki; Akitaya, Hiroshi; Yoshida, Michitoshi [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Arai, Akira; Honda, Satoshi [Center for Astronomy, University of Hyogo, 407-2 Nishigaichi, Sayo-cho, Sayo, Hyogo 679-5313 (Japan); Nishiyama, Koichi [Kurume, Fukuoka-ken (Japan); Kabashima, Fujio, E-mail: yamanaka@kwasan.kyoto-u.ac.jp [Miyaki-cho, Saga-ken (Japan)

    2014-02-20

    We report photometric and spectroscopic observations of the nearby Type Ia Supernova (SN Ia) 2012ht from –15.8 days to +49.1 days after B-band maximum. The decline rate of the light curve is Δm {sub 15}(B) = 1.39 ± 0.05 mag, which is intermediate between normal and subluminous SNe Ia, and similar to that of the ''transitional'' Type Ia SN 2004eo. The spectral line profiles also closely resemble those of SN 2004eo. We were able to observe SN 2012ht at a very early phase, when it was still rising and was about three magnitudes fainter than at the peak. The rise time to the B-band maximum is estimated to be 17.6 ± 0.5 days and the time of the explosion is MJD 56277.98 ± 0.13. SN 2012ht is the first transitional SN Ia whose rise time is directly measured without using light curve templates, and the fifth SN Ia overall. This rise time is consistent with those of the other four SNe within the measurement error, even including the extremely early detection of SN 2013dy. The rising part of the light curve can be fitted by a quadratic function, and shows no sign of a shock-heating component due to the interaction of the ejecta with a companion star. The rise time is significantly longer than that inferred for subluminous SNe such as SN 1991bg, which suggests that a progenitor and/or explosion mechanism of transitional SNe Ia are more similar to normal SNe Ia rather than to subluminous SNe Ia.

  5. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Valencia, Frank Dan

    Concurrent constraint programming (ccp) is a formalism for concurrency in which agents interact with one another by telling (adding) and asking (reading) information in a shared medium. Temporal ccp extends ccp by allowing agents to be constrained by time conditions. This dissertation studies...

  6. A multimedia constraint system

    NARCIS (Netherlands)

    J.E.A. van Hintum; G.J. Reynolds

    1995-01-01

    textabstractThe MADE constraint system provides excellent opportunities to introduce constraints in a multimedia application. Multimedia applications are not only a good place to experiment with constraint systems; constraints in a multimedia environment are almost indispensable. Due to the

  7. ICA analysis of fMRI with real-time constraints: an evaluation of fast detection performance as function of algorithms, parameters and a priori conditions.

    Science.gov (United States)

    Soldati, Nicola; Calhoun, Vince D; Bruzzone, Lorenzo; Jovicich, Jorge

    2013-01-01

    Independent component analysis (ICA) techniques offer a data-driven possibility to analyze brain functional MRI data in real-time. Typical ICA methods used in functional magnetic resonance imaging (fMRI), however, have been until now mostly developed and optimized for the off-line case in which all data is available. Real-time experiments are ill-posed for ICA in that several constraints are added: limited data, limited analysis time and dynamic changes in the data and computational speed. Previous studies have shown that particular choices of ICA parameters can be used to monitor real-time fMRI (rt-fMRI) brain activation, but it is unknown how other choices would perform. In this rt-fMRI simulation study we investigate and compare the performance of 14 different publicly available ICA algorithms systematically sampling different growing window lengths (WLs), model order (MO) as well as a priori conditions (none, spatial or temporal). Performance is evaluated by computing the spatial and temporal correlation to a target component as well as computation time. Four algorithms are identified as best performing (constrained ICA, fastICA, amuse, and evd), with their corresponding parameter choices. Both spatial and temporal priors are found to provide equal or improved performances in similarity to the target compared with their off-line counterpart, with greatly reduced computation costs. This study suggests parameter choices that can be further investigated in a sliding-window approach for a rt-fMRI experiment.

  8. CT coronary angiography at an ultra-low radiation dose (<0.1 mSv): feasible and viable in times of constraint on healthcare costs

    Energy Technology Data Exchange (ETDEWEB)

    Cademartiri, Filippo [Erasmus Medical Center University, Department of Radiology, Rotterdam (Netherlands); Giovanni XXIII Clinic, Cardiovascular Imaging Unit, Monastier di Treviso (Italy); Maffei, Erica; Arcadi, Teresa [Giovanni XXIII Clinic, Cardiovascular Imaging Unit, Monastier di Treviso (Italy); Catalano, Onofrio [IRCCS, SDN Foundation, Naples (Italy); Midiri, Massimo [University of Palermo, Department of Radiology, Palermo (Italy)

    2013-03-15

    Computed tomography coronary angiography (CTCA) has reached very high standards both in terms of diagnostic performance and radiation dose reduction. This commentary follows a report on CTCA using less than 0.1 mSv in selected patients. This is an extraordinary accomplishment, both for technology and for medicine. The difficult task is now to implement this tool in clinical practice so it can play the best possible role. CTCA can improve diagnostic pathways, can save money for healthcare systems and could even improve pharmacological therapy. All of this may happen, but it will require the combined effort of all the experienced operators in this field, including the referring clinicians. In times of financial constraint, CTCA may also help to restrict ineffective medical expenses. (orig.)

  9. Economic Design of Multi-echelon Inventory System with Variable Lead Time and Service Level Constraint in a Fuzzy Cost Environment

    Directory of Open Access Journals (Sweden)

    S. Priyan

    2016-12-01

    Full Text Available Normally, human based industrial decision making involves both quantitative and qualitative input factors such as ordering cost, setup cost, etc. Thus the practitioners should be careful in accounting flexibility in the input factors. This paper optimizes an inventory system by employing mathematical model with variable lead time and service level constraint (SLC in a fuzzy cost environment. Fuzziness is established by allowing the cost components imprecise and vague to certain extent. Trapezoidal and triangular fuzzy numbers are used to represent these characteristics. We also use signed distance method to defuzzify the fuzzy joint total expected cost and differential calculus optimization technique is adopted to find all optimal solutions to the model. Numerical results highlighting the sensitivity in the decision variables are also described.

  10. Constraints on the crustal structure beneath the Sinai subplate, SE Mediterranean, from analysis of local and regional travel times

    Directory of Open Access Journals (Sweden)

    Mohamed K. Salah

    2013-03-01

    Full Text Available The Sinai Peninsula has been recognized as a subplate of the African Plate located at the triple junction of the Gulf of Suez rift, the Dead Sea Transform fault, and the Red Sea rift. The upper and lower crustal structures of this tectonically active, rapidly developing region are yet poorly understood because of many limitations. For this reason, a set of P- and S-wave travel times recorded at 14 seismic stations belonging to the Egyptian National Seismographic Network (ENSN from 111 local and regional events are analyzed to investigate the crustal structures and the locations of the seismogenic zones beneath central and southern Sinai. Because the velocity model used for routine earthquake location by ENSN is one-dimensional, the travel-time residuals will show lateral heterogeneity of the velocity structures and unmodeled vertical structures. Seismic activity is strong along the eastern and southern borders of the study area but low to moderate along the northern boundary and the Gulf of Suez to the west. The crustal Vp/Vs ratio is 1.74 from shallow (depth ≤ 10 km earthquakes and 1.76 from deeper (depth > 10 km crustal events. The majority of the regional and local travel-time residuals are positive relative to the Preliminary Reference Earth Model (PREM, implying that the seismic stations are located above widely distributed, tectonically-induced low-velocity zones. These low-velocity zones are mostly related to the local crustal faults affecting the sedimentary section and the basement complex as well as the rifting processes prevailing in the northern Red Sea region and the ascending of hot mantle materials along crustal fractures. The delineation of these low-velocity zones and the locations of big crustal earthquakes enable the identification of areas prone to intense seismotectonic activities, which should be excluded from major future development projects and large constructions in central and southern Sinai.

  11. Constraints on the Timing and Style of Paleogene Extension in the Basin and Range from Apatite and Zircon Double Dating

    Science.gov (United States)

    Canada, A.; Cassel, E. J.; Stockli, D. F.; Smith, M. E.; Jicha, B. R.; Singer, B. S.

    2016-12-01

    In the Paleogene hinterland of the Sevier orogenic belt, from eastern Nevada to western Utah, high-elevation intermontane basins record widespread accommodation and early-onset extension within the Basin and Range. Detrital zircon U-Pb-He double dating of siliciclastic sediments deposited across the width of the Cordilleran hinterland shows that early and middle Eocene sediments are predominantly multi-cycle and consistent with gradual erosional exhumation of the hinterland. During the middle Eocene and into the early Oligocene, volcanic glass hydration waters indicate that Copper Basin formed at an elevation of 3 km in northeastern Nevada. The basin contains a 1.5 km-thick sequence of fluvial, lacustrine, and volcanic rocks that accumulated on the footwall of the Copper Creek normal fault and conformably above Paleozoic sediments. Detrital zircon and apatite double dating of Paleogene sediments from Copper Basin enables comparison of sedimentary lag times at various phases of basin evolution. We interpret sedimentary lag times within a chronostratigraphic framework developed from 6 new single crystal sanidine 40Ar/39Ar ages for Copper Basin tuff beds. Fluvial sedimentology and detrital zircon U-Pb age populations indicate that proximal volcanic sources were the dominate source of detritus to Copper Basin until a Cretaceous back-arc pluton, the Coffeepot Stock, unroofed along the Copper Creek normal fault during the middle Eocene. Laser Ablation Split Stream-ICPMS U-Pb dating of detrital apatite from Copper Basin sediments corroborates derivation from the 109 Ma Coffeepot Stock. Double dating of zircon grains derived from the Coffeepot Stock shows moderate lag times of 25-50 Myr whereas apatite grains imply lag times of cooling along the Copper Creek normal fault, which continued through the early Oligocene, was likely triggered by the onset of proximal 45 Ma volcanism in the Northern Bull Run Caldera of northeastern Nevada. Rapid early-onset extension in this

  12. Tightened constraints on the time-lag between Antarctic temperature and CO2 during the last deglaciation

    DEFF Research Database (Denmark)

    Pedro, Joel Benjamin; Rasmussen, Sune Olander; van Ommen, Tas D.

    2012-01-01

    Antarctic ice cores provide clear evidence of a close coupling between variations in Antarctic temperature and the atmospheric concentration of CO2 during the glacial/interglacial cycles of at least the past 800-thousand years. Precise information on the relative timing of the temperature and CO2...... lead of CO2 over temperature cannot be excluded. This result, consistent for both CO2 records, implies a faster coupling between temperature and CO2 than previous estimates, which had permitted up to millennial-scale lags....

  13. Digitizing an Analog Radiography Teaching File Under Time Constraint: Trade-Offs in Efficiency and Image Quality.

    Science.gov (United States)

    Loehfelm, Thomas W; Prater, Adam B; Debebe, Tequam; Sekhar, Aarti K

    2017-02-01

    We digitized the radiography teaching file at Black Lion Hospital (Addis Ababa, Ethiopia) during a recent trip, using a standard digital camera and a fluorescent light box. Our goal was to photograph every radiograph in the existing library while optimizing the final image size to the maximum resolution of a high quality tablet computer, preserving the contrast resolution of the radiographs, and minimizing total library file size. A secondary important goal was to minimize the cost and time required to take and process the images. Three workers were able to efficiently remove the radiographs from their storage folders, hang them on the light box, operate the camera, catalog the image, and repack the radiographs back to the storage folder. Zoom, focal length, and film speed were fixed, while aperture and shutter speed were manually adjusted for each image, allowing for efficiency and flexibility in image acquisition. Keeping zoom and focal length fixed, which kept the view box at the same relative position in all of the images acquired during a single photography session, allowed unused space to be batch-cropped, saving considerable time in post-processing, at the expense of final image resolution. We present an analysis of the trade-offs in workflow efficiency and final image quality, and demonstrate that a few people with minimal equipment can efficiently digitize a teaching file library.

  14. Late Noachian Climate Of Mars: Constraints From Valley Network System Formation Times And The Intermittencies (Episodic/Periodic And Punctuated).

    Science.gov (United States)

    Head, James

    2017-04-01

    Formation of Late Noachian-Early Hesperian (LN-EH) valley network systems (VNS) signaled the presence of warm/wet conditions generating several hypotheses for climates permissive of these conditions. To constrain options for the ambient Noachian climate, we examine estimates for time required to carve channels/deltas and total duration implied by plausible intermittencies. Formation Times for VN, OBL, Deltas, Fans: A synthesis of required timescales show that even with the longest estimated continuous duration of VN formation/intermittencies, total time to carve the VN does not exceed 106 years, 273 K, hydrological system vertically integrated, and rainfall occurs to recharge the aquifer. Two subtypes: a) "Rainfall/Fluvial Erosion-Dominated Warm and Wet Model": "Rainfall and surface runoff" persist throughout Noachian to explain crater degradation, and a LN-EH short rapidly ending terminal epoch. b) "Recharge Evaporation/Evaporite Dominated Warm and Wet Model": Sustained period of equatorial/mid-latitude precipitation and a vertically integrated hydrological system driven by evaporative upwelling and fluctuating shallow water table playa environments account for sulfate evaporate environments at Meridiani Planum. Sustained temperatures >273 K are required for extended periods (107-108 years). 2) Cold and icy climate: Sustained background temperatures extremely low (MAT ˜225 K), cryosphere is globally continuous, hydrological system is horizontally stratified, separating groundwater system from surface; no combination of spin-axis/orbital perturbations can raise MAT to 273 K. Adiabatic cooling effects transfer water to high altitudes, leading to "Late Noachian Icy Highlands Model". VNS cannot form in this nominal climate environment without special circumstances (e.g., impacts or volcanic eruptions elevate of temperatures by >˜50 K to induce melting and fluvial/lacustrine activity). 3) Cold and Icy climate warmed by greenhouse gases: The climate is sustained cold

  15. Boring of full scale deposition holes at the Aespoe Hard Rock Laboratory. Operational experiences including boring performance and a work time analysis

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Christer [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Johansson, Aasa [SWECO, Stockholm (Sweden)

    2002-12-01

    Thirteen experimental deposition holes similar to those in the present KBS-3 design have been bored at the Aespoe Hard Rock Laboratory, Oskarshamn, Sweden. The objective with the boring program was to test and demonstrate the current technique for boring of large vertical holes in granitic rock. Conclusions and results from this project is used in the planning process for the deposition holes that will be bored in the real repository for spent nuclear fuel. The boreholes are also important for three major projects. The Prototype Repository, the Canister Retrieval Test and the Demonstration project will all need full-scale deposition holes for their commissioning. The holes are bored in full scale and have a radius of 1.75 m and a depth of 8.5 m. To bore the holes an existing TBM design was modified to produce a novel type Shaft Boring Machine (SBM) suitable for boring 1.75 m diameter holes from a relatively small tunnel. The cutter head was equipped with two types of roller cutters: two row carbide button cutters and disc cutters. Removal of the cuttings was made with a vacuum suction system. The boring was monitored and boring parameters recorded by a computerised system for the evaluation of the boring performance. During boring of four of the holes temperature, stress and strain measurements were performed. Acoustic emission measurements were also performed during boring of these four holes. The results of these activities will not be discussed in this report since they are reported separately. Criteria regarding nominal borehole diameter, deviation of start and end centre point, surface roughness and performance of the machine were set up according to the KBS-3 design and were fulfilled with a fair margin. The average total time for boring one deposition hole during this project was 105 hours.

  16. Transfer effects of manipulating temporal constraints on learning a two-choice reaction time task with low stimulus-response compatibility.

    Science.gov (United States)

    Chen, David D; Pei, Laura; Chan, John S Y; Yan, Jin H

    2012-10-01

    Recent research using deliberate amplification of spatial errors to increase motor learning leads to the question of whether amplifying temporal errors may also facilitate learning. We investigated transfer effects caused by manipulating temporal constraints on learning a two-choice reaction time (CRT) task with varying degrees of stimulus-response compatibility. Thirty-four participants were randomly assigned to one of the three groups and completed 120 trials during acquisition. For every fourth trial, one group was instructed to decrease CRT by 50 msec. relative to the previous trial and a second group was instructed to increase CRT by 50 msec. The third group (the control) was told not to change their responses. After a 5-min. break, participants completed a 40-trial no-feedback transfer test. A 40-trial delayed transfer test was administered 24 hours later. During acquisition, the Decreased Reaction Time group responded faster than the two other groups, but this group also made more errors than the other two groups. In the 5-min. delayed test (immediate transfer), the Decreased Reaction Time group had faster reaction times than the other two groups, while for the 24-hr. delayed test (delayed transfer), both the Decreased Reaction Time group and Increased Reaction Time group had significantly faster reaction times than the control. For delayed transfer, both Decreased and Increased Reaction Time groups reacted significantly faster than the control group. Analyses of error scores in the transfer tests indicated revealed no significant group differences. Results were discussed with regard to the notion of practice variability and goal-setting benefits.

  17. Late Neogene Volcanic Stratigraphy in the Southern Puertecitos Volcanic Province of Baja California: Time Constraints and Vent Source Location

    Science.gov (United States)

    Garcia-Carrillo, P.; Martin, A.; Lopez-Martinez, M.; Cañon, E.

    2007-05-01

    Late Neogene syn-rift explosive volcanism occurred in the Puertecitos Volcanic Province along the western margin of the Gulf of California. This volcanic episode is possibly related to extension during opening of the lower Delfin basin in mid-late Pliocene time. The volcanic stratigraphy in the southern Puertecitos Volcanic Province comprises three main groups: group 1 is a mid-Miocene, arc-related volcanic and sedimentary apron. Groups 2 and 3 are syn-rift volcanic units interstratified within alluvial conglomerate. Group 2 includes a non-welded, crystal-rich pyroclastic flow deposit, and a dark glassy dacite lava flow. Distinctive mineralogy of the crystal tuff is augite, sanidine-microcline and quartz. Two 39Ar/40Ar laser step-heating experiments on sanidine grains yielded an 6.18 ± 0.03 Ma isochron age, consistent with a 6.1 ± 0.4 Ma plateau age obtained in the dacite lava. Thickness of the crystal tuff varies from 35 m in the northeast to 10 m in the southwest along 5 km of distance. Group 3 is characterized by the lack of quartz and potassic feldspar phenocrysts. Three laser step heating experiments on groundmass samples constrain this pulse of explosive volcanism between 2.9 ± 0.1 and 2.3 ± 0.03 Ma. Thicknesses of individual units increase to the northeast and collectively reach up to 150 m. Isopath maps for distinctive flow-units indicate consistent dispersion direction to the SW (average azimuth 210° ± 15°). This inferred flow direction is similar to the orientation of magnetic susceptibility axes measured in 20 oriented samples that yield a mean azimuth of 214°± 24°. In group 3 flow-units eutaxitic foliation is concordant and dips 8-20° to the ENE. Tilting of the volcanic sequence is produced by a series of NNW-trending, west-dipping, high-angle normal faults with less than 40 m of throw. Balanced cross- sections in the southern Puertecitos Volcanic Province indicates that post-2.8 Ma extension is less than 15% suggesting that major deformation

  18. Production of hard coal and world trade have declined for the first time in years; Steinkohlengewinnung und -welthandel erstmals seit Jahren ruecklaeufig

    Energy Technology Data Exchange (ETDEWEB)

    Pasche, Eckart

    2016-10-15

    At the beginning of August, the Association of Coal Importers (VDKi) presented its statistics on hard coal production and trade for 2015 as well as forecasts for the current year. The emissions of hard coal and natural gas in the entire value-added chain were determined and also explained by the contracted consulting firm Poeyry. [German] Anfang August stellte der Verein der Kohlenimporteure (VDKi) seine Statistik ueber Steinkohlengewinnung und -handel fuer 2015 sowie Prognosen fuer das laufende Jahr vor. Dabei wurden auch die in seinem Auftrag vom Beratungsunternehmen Poeyry ermittelten Emissionen von Steinkohle und Erdgas in der gesamten Wertschoepfungskette erlaeutert.

  19. Is a 4-bit synaptic weight resolution enough? - constraints on enabling spike-timing dependent plasticity in neuromorphic hardware.

    Science.gov (United States)

    Pfeil, Thomas; Potjans, Tobias C; Schrader, Sven; Potjans, Wiebke; Schemmel, Johannes; Diesmann, Markus; Meier, Karlheinz

    2012-01-01

    Large-scale neuromorphic hardware systems typically bear the trade-off between detail level and required chip resources. Especially when implementing spike-timing dependent plasticity, reduction in resources leads to limitations as compared to floating point precision. By design, a natural modification that saves resources would be reducing synaptic weight resolution. In this study, we give an estimate for the impact of synaptic weight discretization on different levels, ranging from random walks of individual weights to computer simulations of spiking neural networks. The FACETS wafer-scale hardware system offers a 4-bit resolution of synaptic weights, which is shown to be sufficient within the scope of our network benchmark. Our findings indicate that increasing the resolution may not even be useful in light of further restrictions of customized mixed-signal synapses. In addition, variations due to production imperfections are investigated and shown to be uncritical in the context of the presented study. Our results represent a general framework for setting up and configuring hardware-constrained synapses. We suggest how weight discretization could be considered for other backends dedicated to large-scale simulations. Thus, our proposition of a good hardware verification practice may rise synergy effects between hardware developers and neuroscientists.

  20. Is a 4-Bit Synaptic Weight Resolution Enough? – Constraints on Enabling Spike-Timing Dependent Plasticity in Neuromorphic Hardware

    Science.gov (United States)

    Pfeil, Thomas; Potjans, Tobias C.; Schrader, Sven; Potjans, Wiebke; Schemmel, Johannes; Diesmann, Markus; Meier, Karlheinz

    2012-01-01

    Large-scale neuromorphic hardware systems typically bear the trade-off between detail level and required chip resources. Especially when implementing spike-timing dependent plasticity, reduction in resources leads to limitations as compared to floating point precision. By design, a natural modification that saves resources would be reducing synaptic weight resolution. In this study, we give an estimate for the impact of synaptic weight discretization on different levels, ranging from random walks of individual weights to computer simulations of spiking neural networks. The FACETS wafer-scale hardware system offers a 4-bit resolution of synaptic weights, which is shown to be sufficient within the scope of our network benchmark. Our findings indicate that increasing the resolution may not even be useful in light of further restrictions of customized mixed-signal synapses. In addition, variations due to production imperfections are investigated and shown to be uncritical in the context of the presented study. Our results represent a general framework for setting up and configuring hardware-constrained synapses. We suggest how weight discretization could be considered for other backends dedicated to large-scale simulations. Thus, our proposition of a good hardware verification practice may rise synergy effects between hardware developers and neuroscientists. PMID:22822388

  1. Thermodynamic hardness and the maximum hardness principle

    Science.gov (United States)

    Franco-Pérez, Marco; Gázquez, José L.; Ayers, Paul W.; Vela, Alberto

    2017-08-01

    An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T-1(I -A ) , where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.

  2. Fluid pressure arrival time tomography: Estimation and assessment in the presence of inequality constraints, with an application to a producing gas field at Krechba, Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Rucci, A.; Vasco, D.W.; Novali, F.

    2010-04-01

    Deformation in the overburden proves useful in deducing spatial and temporal changes in the volume of a producing reservoir. Based upon these changes we estimate diffusive travel times associated with the transient flow due to production, and then, as the solution of a linear inverse problem, the effective permeability of the reservoir. An advantage an approach based upon travel times, as opposed to one based upon the amplitude of surface deformation, is that it is much less sensitive to the exact geomechanical properties of the reservoir and overburden. Inequalities constrain the inversion, under the assumption that the fluid production only results in pore volume decreases within the reservoir. We apply the formulation to satellite-based estimates of deformation in the material overlying a thin gas production zone at the Krechba field in Algeria. The peak displacement after three years of gas production is approximately 0.5 cm, overlying the eastern margin of the anticlinal structure defining the gas field. Using data from 15 irregularly-spaced images of range change, we calculate the diffusive travel times associated with the startup of a gas production well. The inequality constraints are incorporated into the estimates of model parameter resolution and covariance, improving the resolution by roughly 30 to 40%.

  3. The last glaciation of Bear Peninsula, central Amundsen Sea Embayment of Antarctica: Constraints on timing and duration revealed by in situ cosmogenic 14C and 10Be dating

    Science.gov (United States)

    Johnson, Joanne S.; Smith, James A.; Schaefer, Joerg M.; Young, Nicolás E.; Goehring, Brent M.; Hillenbrand, Claus-Dieter; Lamp, Jennifer L.; Finkel, Robert C.; Gohl, Karsten

    2017-12-01

    Ice streams in the Pine Island-Thwaites region of West Antarctica currently dominate contributions to sea level rise from the Antarctic ice sheet. Predictions of future ice-mass loss from this area rely on physical models that are validated with geological constraints on past extent, thickness and timing of ice cover. However, terrestrial records of ice sheet history from the region remain sparse, resulting in significant model uncertainties. We report glacial-geological evidence for the duration and timing of the last glaciation of Hunt Bluff, in the central Amundsen Sea Embayment. A multi-nuclide approach was used, measuring cosmogenic 10Be and in situ14C in bedrock surfaces and a perched erratic cobble. Bedrock 10Be ages (118-144 ka) reflect multiple periods of exposure and ice-cover, not continuous exposure since the last interglacial as had previously been hypothesized. In situ14C dating suggests that the last glaciation of Hunt Bluff did not start until 21.1 ± 5.8 ka - probably during the Last Glacial Maximum - and finished by 9.6 ± 0.9 ka, at the same time as ice sheet retreat from the continental shelf was complete. Thickening of ice at Hunt Bluff most likely post-dated the maximum extent of grounded ice on the outer continental shelf. Flow re-organisation provides a possible explanation for this, with the date for onset of ice-cover at Hunt Bluff providing a minimum age for the timing of convergence of the Dotson and Getz tributaries to form a single palaeo-ice stream. This is the first time that timing of onset of ice cover has been constrained in the Amundsen Sea Embayment.

  4. Time and depth scales of fine sediment delivery into gravel stream beds: Constraints from fallout radionuclides on fine sediment residence time and delivery

    Science.gov (United States)

    Gartner, J. D.; Renshaw, C. E.; Dade, W. B.; Magilligan, F. J.

    2012-05-01

    Particles of fine sediment can clog interstitial pore spaces of coarser grained sediment in river beds and thereby impede the exchange of water, dissolved constituents, and particulate matter with consequent ecological impacts. The extent to which fine sediment reduces connectivity between the stream bed and overlying channel is a function, in part, of sediment residence time. Short residence times imply frequent exchange of matter and reduced impact of fine sediment on stream bed habitat, while long residence times indicate that with respect to fine sediment delivery, the stream bed is more isolated from the overlying channel. Here we present a novel technique to quantify the residence time of river bed sediment at various depths over annual and decadal timescales using the fallout radionuclides (FRNs) 7Be (t1/2 = 53 days) and 210Pbex (t1/2 = 22.3 years). We placed mesh cylinders filled with 7Be-free sediment into a stream bed to quantify the capture of 7Be-tagged particles in the absence of scour and fill. We also took cores to the depth of refusal in alluvial sediment in unregulated and regulated rivers in Vermont and New Hampshire. Sampled watershed areas ranged from 29 to 410 km2, and core depths ranged from 19 to 77 cm. The 210Pbex activity profiles of cores show that bed sediment is exchanged to the depth of refusal at decadal timescales. In contrast, 7Be activity profiles indicate that fine sediment infiltrating into the bed had residence times ranging from 4 to > 300 days in unregulated rivers. Cores from a regulated river are notably different—subsurface sediment residence times were always longer than in unregulated rivers at comparable depths, likely owing to restriction of bed mobilization and clogging of bed material by fine sediment. These results suggest that filtration can be an important component of bed material delivery to stream beds, but filtration does not deliver material as deeply into the bed as scour and fill. We find that fallout

  5. Inferring Broad Regulatory Biology from Time Course Data: Have We Reached an Upper Bound under Constraints Typical of In Vivo Studies?

    Directory of Open Access Journals (Sweden)

    Saurabh Vashishtha

    Full Text Available There is a growing appreciation for the network biology that regulates the coordinated expression of molecular and cellular markers however questions persist regarding the identifiability of these networks. Here we explore some of the issues relevant to recovering directed regulatory networks from time course data collected under experimental constraints typical of in vivo studies. NetSim simulations of sparsely connected biological networks were used to evaluate two simple feature selection techniques used in the construction of linear Ordinary Differential Equation (ODE models, namely truncation of terms versus latent vector projection. Performance was compared with ODE-based Time Series Network Identification (TSNI integral, and the information-theoretic Time-Delay ARACNE (TD-ARACNE. Projection-based techniques and TSNI integral outperformed truncation-based selection and TD-ARACNE on aggregate networks with edge densities of 10-30%, i.e. transcription factor, protein-protein cliques and immune signaling networks. All were more robust to noise than truncation-based feature selection. Performance was comparable on the in silico 10-node DREAM 3 network, a 5-node Yeast synthetic network designed for In vivo Reverse-engineering and Modeling Assessment (IRMA and a 9-node human HeLa cell cycle network of similar size and edge density. Performance was more sensitive to the number of time courses than to sample frequency and extrapolated better to larger networks by grouping experiments. In all cases performance declined rapidly in larger networks with lower edge density. Limited recovery and high false positive rates obtained overall bring into question our ability to generate informative time course data rather than the design of any particular reverse engineering algorithm.

  6. Decentralized systems with design constraints

    CERN Document Server

    Mahmoud, Magdi S

    2014-01-01

    This volume provides a rigorous examination of the analysis, stability and control of large-scale systems, and addresses the difficulties that arise because of dimensionality, information structure constraints, parametric uncertainty and time-delays.

  7. The risk constrained cash-in-transit vehicle routing problem with time windows

    OpenAIRE

    TALARICO, Luca; Sörensen, Kenneth; Springael, Johan

    2013-01-01

    This paper proposes a variant of the Vehicle Routing Problem in which a particular kind of risk constraint has been introduced to model the problem of routing vehicles in the cash-in-transit industry and a hard time window constraint, with no waiting times, delimits the customer's visit within a specified time interval. Two metaheuristic algorithms have been developed to cope with medium and large instances of the problem. In a computational experiment, the best parameter settings for each al...

  8. Time-Resolved Transcriptomics and Constraint-Based Modeling Identify System-Level Metabolic Features and Overexpression Targets to Increase Spiramycin Production in Streptomyces ambofaciens

    Directory of Open Access Journals (Sweden)

    Marco Fondi

    2017-05-01

    Full Text Available In this study we have applied an integrated system biology approach to characterize the metabolic landscape of Streptomyces ambofaciens and to identify a list of potential metabolic engineering targets for the overproduction of the secondary metabolites in this microorganism. We focused on an often overlooked growth period (i.e., post-first rapid growth phase and, by integrating constraint-based metabolic modeling with time resolved RNA-seq data, we depicted the main effects of changes in gene expression on the overall metabolic reprogramming occurring in S. ambofaciens. Moreover, through metabolic modeling, we unraveled a set of candidate overexpression gene targets hypothetically leading to spiramycin overproduction. Model predictions were experimentally validated by genetic manipulation of the recently described ethylmalonyl-CoA metabolic node, providing evidence that spiramycin productivity may be increased by enhancing the carbon flow through this pathway. The goal was achieved by over-expressing the ccr paralog srm4 in an ad hoc engineered plasmid. This work embeds the first metabolic reconstruction of S. ambofaciens and the successful experimental validation of model predictions and demonstrates the validity and the importance of in silico modeling tools for the overproduction of molecules with a biotechnological interest. Finally, the proposed metabolic reconstruction, which includes manually refined pathways for several secondary metabolites with antimicrobial activity, represents a solid platform for the future exploitation of S. ambofaciens biotechnological potential.

  9. Organizational Constraints on Corporate Public Relations Practitioners.

    Science.gov (United States)

    Ryan, Michael

    1987-01-01

    Catalogs various internal constraints under which many public relations practitioners work, including constraints on (1) access to management; (2) information collection; (3) dissemination of timely, accurate information; and (4) the public relations mission. Reports that most practitioners see organizational constraints as more of a problem for…

  10. Hard photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier / CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble (France)

    2007-07-01

    In view of possible photoproduction studies in ultra-peripheral heavy-ion collisions at the LHC, we briefly review the present theoretical understanding of photons and hard photoproduction processes at HERA, discussing the production of jets, light and heavy hadrons, quarkonia, and prompt photons. We address in particular the extraction of the strong coupling constant from photon structure function and inclusive jet measurements, the infrared safety and computing time of jet definitions, the sensitivity of di-jet cross sections on the parton densities in the photon, factorization breaking in diffractive di-jet production, the treatment of the heavy-quark mass in charm production, the relevance of the color-octet mechanism for quarkonium production, and isolation criteria for prompt photons. (author)

  11. Soft Concurrent Constraint Programming

    OpenAIRE

    Bistarelli, S.; Montanari, U.; Rossi, F.

    2002-01-01

    Soft constraints extend classical constraints to represent multiple consistency levels, and thus provide a way to express preferences, fuzziness, and uncertainty. While there are many soft constraint solving formalisms, even distributed ones, by now there seems to be no concurrent programming framework where soft constraints can be handled. In this paper we show how the classical concurrent constraint (cc) programming framework can work with soft constraints, and we also propose an extension ...

  12. Thermochronology of a convergent orogen: Constraints on the timing of thrust faulting and subsequent exhumation of the Maladeta Pluton in the Central Pyrenean Axial Zone

    Science.gov (United States)

    Metcalf, James R.; Fitzgerald, Paul G.; Baldwin, Suzanne L.; Muñoz, Josep-Anton

    2009-10-01

    The Pyrenees Mountains of Spain and France are a collisional orogen cored by a south-vergent antiformal stack of Paleozoic basement thrust sheets (the Axial Zone). Thrusting accommodated shortening due to convergence between Iberia and Europe. Granitic plutons, intruded during the Hercynian orogeny, form an important component of the basement units. Thermochronology of granodioritic samples collected from a vertical [age-elevation] profile from the south-central Maladeta pluton provide new constraints on the timing of thrust faulting and rock exhumation of the Pyrenean orogen. The Maladeta massif lies within the Orri thrust sheet, presently occupying the immediate footwall of the Gavarnie thrust, a major Axial Zone Alpine-age thrust fault. New biotite and K-feldspar 40Ar/ 39Ar and apatite (U-Th)/He (AHe) data combined with previous apatite fission track (AFT) thermochronology and structural studies of the Maladeta pluton constrain the thermal evolution of this massif. Biotite weighted mean plateau and K-feldspar maximum 40Ar/ 39Ar ages from the highest elevations of the Maladeta pluton (2850 m) are ˜ 280 Ma, close to the age of intrusion, and are interpreted to date the timing of rapid cooling in the Hercynian. Subsequently the Maladeta massif remained close to the surface as indicated by the presence of unconformable Triassic continental sediments. K-feldspar 40Ar/ 39Ar multiple diffusion domain thermal models from two samples at lower elevations (1780 m and 1400 m) indicate heating initiated at ˜ 65 Ma, reaching maximum temperatures of 270 to 280 °C. These data are interpreted to record thrust burial of the Maladeta pluton to depths of ˜ 6-10 km in the footwall of the Gavarnie thrust. Burial and heating were followed by a period of relatively rapid cooling beginning at ˜ 50 Ma, recorded in three K-feldspar thermal models from samples at different elevations (2850 m, 1780 m, and 1400 m). AFT thermal models, in conjunction with the AFT and apatite AHe age

  13. Understanding leachate flow in municipal solid waste landfills by combining time-lapse ERT and subsurface flow modelling - Part II: Constraint methodology of hydrodynamic models.

    Science.gov (United States)

    Audebert, M; Oxarango, L; Duquennoi, C; Touze-Foltz, N; Forquet, N; Clément, R

    2016-09-01

    Leachate recirculation is a key process in the operation of municipal solid waste landfills as bioreactors. To ensure optimal water content distribution, bioreactor operators need tools to design leachate injection systems. Prediction of leachate flow by subsurface flow modelling could provide useful information for the design of such systems. However, hydrodynamic models require additional data to constrain them and to assess hydrodynamic parameters. Electrical resistivity tomography (ERT) is a suitable method to study leachate infiltration at the landfill scale. It can provide spatially distributed information which is useful for constraining hydrodynamic models. However, this geophysical method does not allow ERT users to directly measure water content in waste. The MICS (multiple inversions and clustering strategy) methodology was proposed to delineate the infiltration area precisely during time-lapse ERT survey in order to avoid the use of empirical petrophysical relationships, which are not adapted to a heterogeneous medium such as waste. The infiltration shapes and hydrodynamic information extracted with MICS were used to constrain hydrodynamic models in assessing parameters. The constraint methodology developed in this paper was tested on two hydrodynamic models: an equilibrium model where, flow within the waste medium is estimated using a single continuum approach and a non-equilibrium model where flow is estimated using a dual continuum approach. The latter represents leachate flows into fractures. Finally, this methodology provides insight to identify the advantages and limitations of hydrodynamic models. Furthermore, we suggest an explanation for the large volume detected by MICS when a small volume of leachate is injected. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Hard coal; Steinkohle

    Energy Technology Data Exchange (ETDEWEB)

    Loo, Kai van de; Sitte, Andreas-Peter [Gesamtverband Steinkohle e.V. (GVSt), Herne (Germany)

    2015-07-01

    International the coal market in 2014 was the first time in a long time in a period of stagnation. In Germany, the coal consumption decreased even significantly, mainly due to the decrease in power generation. Here the national energy transition has now been noticable affected negative for coal use. The political guidances can expect a further significant downward movement for the future. In the present phase-out process of the German hard coal industry with still three active mines there was in 2014 no decommissioning. But the next is at the end of 2015, and the plans for the time after mining have been continued. [German] International war der Markt fuer Steinkohle 2014 erstmals seit langem wieder von einer Stagnation gekennzeichnet. In Deutschland ging der Steinkohlenverbrauch sogar deutlich zurueck, vor allem wegen des Rueckgangs in der Stromerzeugung. Hier hat sich die nationale Energiewende nun spuerbar und fuer die Steinkohlennutzung negativ ausgewirkt. Die politischen Weichenstellungen lassen fuer die Zukunft eine weitere erhebliche Abwaertsbewegung erwarten. Bei dem im Auslaufprozess befindlichen deutschen Steinkohlenbergbau mit noch drei aktiven Bergwerken gab es 2014 keine Stilllegung. Doch die naechste steht zum Jahresende 2015 an, und die Planungen fuer die Zeit nach dem Bergbau sind fortgefuehrt worden.

  15. Stochastic Constraint Programming

    OpenAIRE

    Walsh, Toby

    2009-01-01

    To model combinatorial decision problems involving uncertainty and probability, we introduce stochastic constraint programming. Stochastic constraint programs contain both decision variables (which we can set) and stochastic variables (which follow a probability distribution). They combine together the best features of traditional constraint satisfaction, stochastic integer programming, and stochastic satisfiability. We give a semantics for stochastic constraint programs, and propose a number...

  16. Quadratic third-order tensor optimization problem with quadratic constraints

    Directory of Open Access Journals (Sweden)

    Lixing Yang

    2014-05-01

    Full Text Available Quadratically constrained quadratic programs (QQPs problems play an important modeling role for many diverse problems. These problems are in general NP hard and numerically intractable. Semidenite programming (SDP relaxations often provide good approximate solutions to these hard problems. For several special cases of QQP, e.g., convex programs and trust region subproblems, SDP relaxation provides the exact optimal value, i.e., there is a zero duality gap. However, this is not true for the general QQP, or even the QQP with two convex constraints, but a nonconvex objective.In this paper, we consider a certain QQP where the variable is neither vector nor matrix but a third-order tensor. This problem can be viewed as a generalization of the ordinary QQP with vector or matrix as it's variant. Under some mild conditions, we rst show that SDP relaxation provides exact optimal solutions for the original problem. Then we focus on two classes of homogeneous quadratic tensor programming problems which have no requirements on the constraints number. For one, we provide an easily implemental polynomial time algorithm to approximately solve the problem and discuss the approximation ratio. For the other, we show there is no gap between the SDP relaxation and itself.

  17. Hardness Tester for Polyur

    Science.gov (United States)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  18. Comprehensive hard materials

    CERN Document Server

    2014-01-01

    Comprehensive Hard Materials deals with the production, uses and properties of the carbides, nitrides and borides of these metals and those of titanium, as well as tools of ceramics, the superhard boron nitrides and diamond and related compounds. Articles include the technologies of powder production (including their precursor materials), milling, granulation, cold and hot compaction, sintering, hot isostatic pressing, hot-pressing, injection moulding, as well as on the coating technologies for refractory metals, hard metals and hard materials. The characterization, testing, quality assurance and applications are also covered. Comprehensive Hard Materials provides meaningful insights on materials at the leading edge of technology. It aids continued research and development of these materials and as such it is a critical information resource to academics and industry professionals facing the technological challenges of the future. Hard materials operate at the leading edge of technology, and continued res...

  19. Evaluation of the surface hardness of composite resins before and after polishing at different times Avaliação da dureza superficial de resinas compostas antes e após o polimento em diferentes tempos

    Directory of Open Access Journals (Sweden)

    Michelle Alexandra Chinelatti

    2006-06-01

    Full Text Available PURPOSE: The aim of this study was to evaluate the surface hardness of six composite resins: Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (microfilled and Z100 (minifilled before and after polishing at different times. MATERIALS AND METHODS: For this purpose, 240 specimens (5mm diameter, 1.4mm high were prepared. Vickers hardness was determined before and after polishing at different times: immediately, 24h, 7 and 21 days after preparation of the samples. Statistical analysis was performed by ANOVA and Tukey test. RESULTS: There was no difference in the hardness of flowable resins, which had lower hardness than the minifilled resin. The minifilled resin showed the highest surface hardness as compared to the other materials (pPROPOSIÇÃO: O objetivo deste estudo foi avaliar a dureza superficial de seis resinas compostas - Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (micropartículas e Z100 (híbrida - antes e após o polimento realizado em diferentes tempos. MATERIAL E MÉTODO: Foram confeccionados 240 corpos-de-prova circulares (5mm de diâmetro e 1,4mm de altura. A dureza Vickers foi obtida antes e após o polimento realizado em diferentes tempos: imediatamente, 24 horas, 7 dias e 21 dias após a confecção do corpo-de-prova. Os dados foram analisados estatisticamente por meio da ANOVA e do Teste de Tukey. RESULTADOS: Não houve diferença entre as resinas compostas flowable, as quais apresentaram os menores valores de dureza. A resina composta híbrida demonstrou os melhores resultados. Todos os materiais exibiram aumento de dureza após a realização do polimento, que foi mais evidente após 7 dias. CONCLUSÃO: Pôde-se concluir que, independente do tipo de resina composta, a dureza superficial foi consideravelmente maior quando o polimento foi realizado 1 semana após a confecção dos corpos-de-prova.

  20. Hard probes 2006 Asilomar

    CERN Multimedia

    2006-01-01

    "The second international conference on hard and electromagnetic probes of high-energy nuclear collisions was held June 9 to 16, 2006 at the Asilomar Conference grounds in Pacific Grove, California" (photo and 1/2 page)

  1. Crystal Indentation Hardness

    Directory of Open Access Journals (Sweden)

    Ronald W. Armstrong

    2017-01-01

    Full Text Available There is expanded interest in the long-standing subject of the hardness properties of materials. A major part of such interest is due to the advent of nanoindentation hardness testing systems which have made available orders of magnitude increases in load and displacement measuring capabilities achieved in a continuously recorded test procedure. The new results have been smoothly merged with other advances in conventional hardness testing and with parallel developments in improved model descriptions of both elastic contact mechanics and dislocation mechanisms operative in the understanding of crystal plasticity and fracturing behaviors. No crystal is either too soft or too hard to prevent the determination of its elastic, plastic and cracking properties under a suitable probing indenter. A sampling of the wealth of measurements and reported analyses associated with the topic on a wide variety of materials are presented in the current Special Issue.

  2. Hard processes in hadronic interactions

    Energy Technology Data Exchange (ETDEWEB)

    Satz, H. [CERN, Geneva (Switzerland)]|[Universitat Bielefeld (Germany); Wang, X.N. [Lawrence Berkeley Lab., CA (United States)

    1995-07-01

    Quantum chromodynamics is today accepted as the fundamental theory of strong interactions, even though most hadronic collisions lead to final states for which quantitative QCD predictions are still lacking. It therefore seems worthwhile to take stock of where we stand today and to what extent the presently available data on hard processes in hadronic collisions can be accounted for in terms of QCD. This is one reason for this work. The second reason - and in fact its original trigger - is the search for the quark-gluon plasma in high energy nuclear collisions. The hard processes to be considered here are the production of prompt photons, Drell-Yan dileptons, open charm, quarkonium states, and hard jets. For each of these, we discuss the present theoretical understanding, compare the resulting predictions to available data, and then show what behaviour it leads to at RHIC and LHC energies. All of these processes have the structure mentioned above: they contain a hard partonic interaction, calculable perturbatively, but also the non-perturbative parton distribution within a hadron. These parton distributions, however, can be studied theoretically in terms of counting rule arguments, and they can be checked independently by measurements of the parton structure functions in deep inelastic lepton-hadron scattering. The present volume is the work of Hard Probe Collaboration, a group of theorists who are interested in the problem and were willing to dedicate a considerable amount of their time and work on it. The necessary preparation, planning and coordination of the project were carried out in two workshops of two weeks` duration each, in February 1994 at CERn in Geneva andin July 1994 at LBL in Berkeley.

  3. Hardness amplification in nondeterministic logspace

    OpenAIRE

    Gupta, Sushmita

    2007-01-01

    A hard problem is one which cannot be easily computed by efficient algorithms. Hardness amplification is a procedure which takes as input a problem of mild hardness and returns a problem of higher hardness. This is closely related to the task of decoding certain error-correcting codes. We show amplification from mild average case hardness to higher average case hardness for nondeterministic logspace and worst-to-average amplification for nondeterministic linspace. Finally we explore possible ...

  4. X-Ray Timing Analysis of Cyg X-3 Using AstroSat/LAXPC: Detection of Milli-hertz Quasi-periodic Oscillations during the Flaring Hard X-Ray State

    Science.gov (United States)

    Pahari, Mayukh; Antia, H. M.; Yadav, J. S.; Verdhan Chauhan, Jai; Agrawal, P. C.; Misra, Ranjeev; Chitnis, V. R.; Dedhia, Dhiraj; Katoch, Tilak; Madhwani, P.; Manchanda, R. K.; Paul, B.; Shah, Parag

    2017-11-01

    We present here results from the X-ray timing and spectral analysis of the X-ray binary Cyg X-3 using observations from the Large Area X-ray proportional Counter on board AstroSat. Consecutive light curves observed over a period of one year show the binary orbital period of 17253.56 ± 0.19 s. Another low-amplitude, slow periodicity of the order of 35.8 ± 1.4 days is observed, which may be due to the orbital precession as suggested earlier by Molteni et al. During the rising binary phase, power density spectra from different observations during the flaring hard X-ray state show quasi-periodic oscillations (QPOs) at ˜5-8 mHz, ˜12-14 mHz, and ˜18-24 mHz frequencies at the minimum confidence of 99%. However, during the consecutive binary decay phase, no QPO is detected up to 2σ significance. Energy-dependent time-lag spectra show soft lag (soft photons lag hard photons) at the mHz QPO frequency and the fractional rms of the QPO increases with the photon energy. During the binary motion, the observation of mHz QPOs during the rising phase of the flaring hard state may be linked to the increase in the supply of the accreting material in the disk and corona via stellar wind from the companion star. During the decay phase, the compact source moves in the outer wind region causing the decrease in supply of material for accretion. This may cause weakening of the mHz QPOs below the detection limit. This is also consistent with the preliminary analysis of the orbital phase-resolved energy spectra presented in this paper.

  5. The Soft Cumulative Constraint

    OpenAIRE

    Petit, Thierry; Poder, Emmanuel

    2009-01-01

    This research report presents an extension of Cumulative of Choco constraint solver, which is useful to encode over-constrained cumulative problems. This new global constraint uses sweep and task interval violation-based algorithms.

  6. Composing constraint solvers

    NARCIS (Netherlands)

    P. Zoeteweij (Peter)

    2005-01-01

    htmlabstractComposing constraint solvers based on tree search and constraint propagation through generic iteration leads to efficient and flexible constraint solvers. This was demonstrated using OpenSolver, an abstract branch-and-propagate tree search engine that supports a wide range of relevant

  7. A mixed integer programming model for a continuous move transportation problem with service constraints

    Directory of Open Access Journals (Sweden)

    J. Fabian Lopez

    2010-01-01

    Full Text Available We consider a Pickup and Delivery Vehicle Routing Problem (PDP commonly encountered in real-world logistics operations. The problem involves a set of practical complications that have received little attention in the vehicle routing literature. In this problem, there are multiple vehicle types available to cover a set of pickup and delivery requests, each of which has pickup time windows and delivery time windows. Transportation orders and vehicle types must satisfy a set of compatibility constraints that specify which orders cannot be covered by which vehicle types. In addition we include some dock service capacity constraints as is required on common real world operations. This problem requires to be attended on large scale instances (orders ≥ 500, (vehicles ≥ 150. As a generalization of the traveling salesman problem, clearly this problem is NP-hard. The exact algorithms are too slow for large scale instances. The PDP-TWDS is both a packing problem (assign order to vehicles, and a routing problem (find the best route for each vehicle. We propose to solve the problem in three stages. The first stage constructs initials solutions at aggregate level relaxing some constraints on the original problem. The other two stages imposes time windows and dock service constraints. Our results are favorable finding good quality solutions in relatively short computational times.

  8. Optical flow computation using extended constraints.

    Science.gov (United States)

    Del Bimbo, A; Nesi, P; Sanz, J C

    1996-01-01

    Several approaches for optical flow estimation use partial differential equations to model changes in image brightness throughout time. A commonly used equation is the so-called optical flow constraint (OFC), which assumes that the image brightness is stationary with respect to time. More recently, a different constraint referred to as the extended optical flow constraint (EOFC) has been introduced, which also contains the divergence of the flow field of image brightness. There is no agreement in the literature about which of these constraints provides the best estimation of the velocity field. Two new solutions for optical flow computation are proposed, which are based on an approximation of the constraint equations. The two techniques have been used with both EOFC and OFC constraint equations. Results achieved by using these solutions have been compared with several well-known computational methods for optical flow estimation in different motion conditions. Estimation errors have also been measured and compared for different types of motion.

  9. Hard exclusive reactions and generalized parton distributions

    Directory of Open Access Journals (Sweden)

    Hayrapetyan Avetik

    2015-01-01

    Full Text Available The recently developed formalism of Generalized Parton Distributions (GPDs allows connecting the experimental information of hard exclusive reactions to the spin contribution and even to the angular momentum contribution of quarks in the nucleon. By selecting different quantum numbers of the final state in exclusive productions, different GPDs can be addressed separately. The HERMES experiment at the HERA ring at DESY (Hamburg made pioneering contributions and first constraints to Generalized Parton Distributions (GPDs, using hard exclusive vector meson production (EVMP and Deeply Virtual Compton Scattering (DVCS. Using a novel recoil detector, HERMES managed to measure DVCS and EVMP free of any significant background. Selected results are highlighted and discussed in this paper.

  10. Carbon Equivalent and Maximum Hardness

    OpenAIRE

    Haruyoshi, Suzuki; Head Office, Nippon Steel Corporation

    1984-01-01

    The accuracy of formulae for estimating the maximum hardness values of the HAZ from chemical composition and cooling time for welds in high strength steel is discussed and a new formula. NSC-S, is proposed which uses only C%, Pcm% and cooling time for the purpose of satisfactory accuracy. IIW CE and Ito-Bessyo Pcm carbon equivalent alone are not satisfactory in establishing Hmax values. The former is good only for slow cooling, t8/5 longer than 10 seconds, while the latter is good only for fa...

  11. Hard superconducting nitrides

    Science.gov (United States)

    Chen, Xiao-Jia; Struzhkin, Viktor V.; Wu, Zhigang; Somayazulu, Maddury; Qian, Jiang; Kung, Simon; Christensen, Axel Nørlund; Zhao, Yusheng; Cohen, Ronald E.; Mao, Ho-kwang; Hemley, Russell J.

    2005-01-01

    Detailed study of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides reveals interesting correlations among their physical properties. Both the bulk modulus and Vickers hardness are found to decrease with increasing zero-pressure volume in NbN, HfN, and ZrN. The computed elastic constants from first principles satisfy c11 > c12 > c44 for NbN, but c11 > c44 > c12 for HfN and ZrN, which are in good agreement with the neutron scattering data. The cubic δ-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire. Theoretical calculations for NbN show that all elastic moduli increase monotonically with increasing pressure. These results suggest technological applications of such materials in extreme environments. PMID:15728352

  12. Session: Hard Rock Penetration

    Energy Technology Data Exchange (ETDEWEB)

    Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

  13. Hard-hat day

    CERN Multimedia

    2003-01-01

    CERN will be organizing a special information day on Friday, 27th June, designed to promote the wearing of hard hats and ensure that they are worn correctly. A new prevention campaign will also be launched.The event will take place in the hall of the Main Building from 11.30 a.m. to 2.00 p.m., when you will be able to come and try on various models of hard hat, including some of the very latest innovative designs, ask questions and pass on any comments and suggestions.

  14. Holonomic constraints: an analytical result

    Energy Technology Data Exchange (ETDEWEB)

    Mazars, Martial [Laboratoire de Physique Theorique (UMR 8627), Universite de Paris Sud XI, Batiment 210, 91405 Orsay Cedex (France)

    2007-02-23

    Systems subjected to holonomic constraints follow quite complicated dynamics that could not be described easily with Hamiltonian or Lagrangian dynamics. The influence of holonomic constraints in equations of motions is taken into account by using Lagrange multipliers. Finding the value of the Lagrange multipliers allows us to compute the forces induced by the constraints and therefore, to integrate the equations of motions of the system. Computing analytically the Lagrange multipliers for a constrained system may be a difficult task that depends on the complexity of systems. For complex systems it is, most of the time, impossible to achieve. In computer simulations, some algorithms using iterative procedures estimate numerically Lagrange multipliers or constraint forces by correcting the unconstrained trajectory. In this work, we provide an analytical computation of the Lagrange multipliers for a set of linear holonomic constraints with an arbitrary number of bonds of constant length. In the appendix explicit formulae are shown for Lagrange multipliers for systems having 1, 2, 3, 4 and 5 bonds of constant length, linearly connected.

  15. Ground hardness and injury in community level Australian football.

    Science.gov (United States)

    Twomey, Dara M; Finch, Caroline F; Lloyd, David G; Elliott, Bruce C; Doyle, Tim L A

    2012-07-01

    To describe the risk and details of injuries associated with ground hardness in community level Australian football (AF). Prospective injury surveillance with periodic objective ground hardness measurement. 112 ground hardness assessments were undertaken using a Clegg hammer at nine locations across 20 grounds, over the 2007 and 2008 AF seasons. Details of 352 injuries sustained by community level players on those grounds were prospectively collected as part of a large randomised controlled trial. The ground location of the injury was matched to the nearest corresponding ground hardness Clegg hammer readings, in gravities (g), which were classified from unacceptably low (hardness (>120 g). Clegg hammer readings ranged from 25 to 301 g. Clegg hammer hardness categories from low/normal to high/normal were associated with the majority of injuries, with only 3.7% (13 injuries) on unacceptably high hardness and 0.3% (1 injury) on the unacceptably low hardness locations. Relative to the preferred range of hardness, the risk of sustaining an injury on low/normal hardness locations was 1.31 (95%CI: 1.06-1.62) times higher and 1.82 (95%CI: 1.17-2.85) times higher on locations with unacceptably high hardness. The more severe injuries occurred with low/normal ground hardness. Despite the low number of injuries, the risk of sustaining an injury on low/normal and unacceptably hard grounds was significantly greater than on the preferred range of hardness. Notably, the severity of the injuries sustained on unacceptably hard grounds was lower than for other categories of hardness. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  16. Hardness and excitation energy

    Indian Academy of Sciences (India)

    It is shown that the first excitation energy can be given by the Kohn-Sham hardness (i.e. the energy difference of the ground-state lowest unoccupied and highest occupied levels) plus an extra term coming from the partial derivative of the ensemble exchange-correlation energy with respect to the weighting factor in the ...

  17. Hard Probes at ATLAS

    CERN Document Server

    Citron, Z; The ATLAS collaboration

    2014-01-01

    The ATLAS collaboration has measured several hard probe observables in Pb+Pb and p+Pb collisions at the LHC. These measurements include jets which show modification in the hot dense medium of heavy ion collisions as well as color neutral electro-weak bosons. Together, they elucidate the nature of heavy ion collisions.

  18. Hardness of metallic crystals

    Indian Academy of Sciences (India)

    Administrator

    where H is the hardness, k the coefficient, G the shear modulus, ν the Poisson's ratio, η a function of the radius of an atom (r) and the electron density at the atom interface (n). The formula will not only be used to testify the critical grain size with stable dislocations, but also play an important role in the understanding of ...

  19. CSI: Hard Drive

    Science.gov (United States)

    Sturgeon, Julie

    2008-01-01

    Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.…

  20. Hard and Soft Governance

    DEFF Research Database (Denmark)

    Moos, Lejf

    2009-01-01

    The governance and leadership at transnational, national and school level seem to be converging into a number of isomorphic forms as we see a tendency towards substituting 'hard' forms of governance, that are legally binding, with 'soft' forms based on persuasion and advice. This article analyses...

  1. Hardness and excitation energy

    Indian Academy of Sciences (India)

    Unknown

    form a new species leading to a single electronegativity or chemical potential (the same way as in ordinary thermodynamics). The hardness η of an electronic system is ..... Technological Innovation Foundation and the Minis- try of Science and Technology. This work was also supported by the grant OTKA No. T042505.

  2. "Soft"or "hard" ionisation? Investigation of metastable gas temperature effect on direct analysis in real-time analysis of Voriconazole.

    Science.gov (United States)

    Lapthorn, Cris; Pullen, Frank

    2009-01-01

    The performance of the direct analysis in real-time (DART) technique was evaluated across a range of metastable gas temperatures for a pharmaceutical compound, Voriconazole, in order to investigate the effect of metastable gas temperature on molecular ion intensity and fragmentation. The DART source has been used to analyse a range of analytes and from a range of matrices including drugs in solid tablet form and preparations, active ingredients in ointment, naturally occurring plant alkaloids, flavours and fragrances, from thin layer chromatography (TLC) plates, melting point tubes and biological matrices including hair, urine and blood. The advantages of this technique include rapid analysis time (as little as 5 s), a reduction in sample preparation requirements, elimination of mobile phase requirement and analysis of samples not typically amenable to atmospheric pressure ionisation (API) techniques. This technology has therefore been proposed as an everyday tool for identification of components in crude organic reaction mixtures.

  3. Communication: Generalizing Rosenfeld's excess-entropy scaling to predict long-time diffusivity in dense fluids of Brownian particles: from hard to ultrasoft interactions.

    Science.gov (United States)

    Pond, Mark J; Errington, Jeffrey R; Truskett, Thomas M

    2011-02-28

    Computer simulations are used to test whether a recently introduced generalization of Rosenfeld's excess-entropy scaling method for estimating transport coefficients in systems obeying molecular dynamics can be extended to predict long-time diffusivities in fluids of particles undergoing Brownian dynamics in the absence of interparticle hydrodynamic forces. Model fluids with inverse-power-law, Gaussian-core, and Hertzian pair interactions are considered. Within the generalized Rosenfeld scaling method, long-time diffusivities of ultrasoft Gaussian-core and Hertzian particle fluids, which display anomalous trends with increasing density, are predicted (to within 20%) based on knowledge of interparticle interactions, excess entropy, and scaling behavior of simpler inverse-power-law fluids.

  4. A Temporal Concurrent Constraint Programming Calculus

    DEFF Research Database (Denmark)

    Palamidessi, Catuscia; Valencia Posso, Frank Darwin

    2001-01-01

    The tcc model is a formalism for reactive concurrent constraint programming. In this paper we propose a model of temporal concurrent constraint programming which adds to tcc the capability of modeling asynchronous and non-deterministic timed behavior. We call this tcc extension the ntcc calculus...

  5. Macroindentation hardness measurement-Modernization and applications.

    Science.gov (United States)

    Patel, Sarsvat; Sun, Changquan Calvin

    2016-06-15

    In this study, we first developed a modernized indentation technique for measuring tablet hardness. This technique is featured by rapid digital image capture, using a calibrated light microscope, and precise area-determination. We then systematically studied effects of key experimental parameters, including indentation force, speed, and holding time, on measured hardness of a very soft material, hydroxypropyl cellulose, and a very hard material, dibasic calcium phosphate, to cover a wide range of material properties. Based on the results, a holding period of 3min at the peak indentation load is recommended to minimize the effect of testing speed on H. Using this method, we show that an exponential decay function well describes the relationship between tablet hardness and porosity for seven commonly used pharmaceutical powders investigated in this work. We propose that H and H at zero porosity may be used to quantify the tablet deformability and powder plasticity, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. “I Can Only Work So Hard Before I Burn Out.” A Time Sensitive Conceptual Integration of Ideological Psychological Contract Breach, Work Effort, and Burnout

    Directory of Open Access Journals (Sweden)

    Samantha K. Jones

    2018-02-01

    Full Text Available Employees often draw meaning from personal experiences and contributions in their work, particularly when engaging in organizational activities that align with their personal identity or values. However, recent empirical findings have demonstrated how meaningful work can also have a negative effect on employee’s well-being as employees feel so invested in their work, they push themselves beyond their limits resulting in strain and susceptibility to burnout. We develop a framework to understand this “double edged” role of meaningful work by drawing from ideological psychological contracts (iPCs, which are characterized by employees and their employer who are working to contribute to a shared ideology or set of values. Limited iPC research has demonstrated employees may actually work harder in response to an iPC breach. In light of these counterintuitive findings, we propose the following conceptual model to theoretically connect our understanding of iPCs, perceptions of breach, increases in work effort, and the potential “dark side” of repeated occurrences of iPC breach. We argue that time plays a central role in the unfolding process of employees’ reactions to iPC breach over time. Further, we propose how perceptions of iPC breach relate to strain and, eventually, burnout. This model contributes to our understanding of the role of time in iPC development and maintenance, expands our exploration of ideology in the PC literature, and provides a framework to understanding why certain occupations are more susceptible to instances of strain and burnout. This framework has the potential to guide future employment interventions in ideology-infused organizations to help mitigate negative employee outcomes.

  7. Quiet planting in the locked constraints satisfaction problems

    Energy Technology Data Exchange (ETDEWEB)

    Zdeborova, Lenka [Los Alamos National Laboratory; Krzakala, Florent [Los Alamos National Laboratory

    2009-01-01

    We study the planted ensemble of locked constraint satisfaction problems. We describe the connection between the random and planted ensembles. The use of the cavity method is combined with arguments from reconstruction on trees and first and second moment considerations; in particular the connection with the reconstruction on trees appears to be crucial. Our main result is the location of the hard region in the planted ensemble, thus providing hard satisfiable benchmarks. In a part of that hard region instances have with high probability a single satisfying assignment.

  8. Scheduling a maintenance activity under skills constraints to minimize total weighted tardiness and late tasks

    Directory of Open Access Journals (Sweden)

    Djalal Hedjazi

    2015-04-01

    Full Text Available Skill management is a key factor in improving effectiveness of industrial companies, notably their maintenance services. The problem considered in this paper concerns scheduling of maintenance tasks under resource (maintenance teams constraints. This problem is generally known as unrelated parallel machine scheduling. We consider the problem with a both objectives of minimizing total weighted tardiness (TWT and number of tardiness tasks. Our interest is focused particularly on solving this problem under skill constraints, which each resource has a skill level. So, we propose a new efficient heuristic to obtain an approximate solution for this NP-hard problem and demonstrate his effectiveness through computational experiments. This heuristic is designed for implementation in a static maintenance scheduling problem (with unequal release dates, processing times and resource skills, while minimizing objective functions aforementioned.

  9. Influence of capacity- and time-constrained intermediate storage in two-stage food production systems

    NARCIS (Netherlands)

    Akkerman, Renzo; van Donk, Dirk Pieter; Gaalman, Gerard

    2007-01-01

    In food processing, two-stage production systems with a batch processor in the first stage and packaging lines in the second stage are common and mostly separated by capacity- and time-constrained intermediate storage. This combination of constraints is common in practice, but the literature hardly

  10. Symbolic Constraints in Constructive Geometric Constraint Solving

    OpenAIRE

    Hoffmann, Christoph M.; Joan-Arinyo, Robert

    1997-01-01

    In design and manufacturing applications, users of computer aided design systems want to define relationships between dimension variables, since such relationships express design intent very flexibly. This work reports on a technique developed to enhance a class of constructive geometric constraint solvers with the capability of managing functional relationships between dimension variables. The method is shown to be correct.

  11. Hard Probes at RHIC

    Directory of Open Access Journals (Sweden)

    Bielčíková Jana

    2014-04-01

    Full Text Available Measurements of jets and heavy flavour, the so called hard probes, play a crucial role in understanding properties of hot and dense nuclear matter created in high energy heavy-ion collisions. The measurements at the Relativistic Heavy Ion Collider (RHIC showed that in central Au+Au collisons at RHIC energy ( √sNN = 200 GeV the nuclear matter created has properties close to those of perfect liquid, manifests partonic degrees of freedom and is opaque to hard probes. In order to draw quantitative conclusions on properties of this hot and dense nuclear matter reference measurements in proton-proton collisions and d+Au collisions are essential to estimate cold nuclear matter effects. In this proceedings a review of recent results on hard probes measurements in p+p, d+Au and A+A collisions as well as of beam energy dependence of jet quenching from STAR and PHENIX experiments at RHIC is presented.

  12. Credit Constraints in Education

    Science.gov (United States)

    Lochner, Lance; Monge-Naranjo, Alexander

    2012-01-01

    We review studies of the impact of credit constraints on the accumulation of human capital. Evidence suggests that credit constraints have recently become important for schooling and other aspects of households' behavior. We highlight the importance of early childhood investments, as their response largely determines the impact of credit…

  13. The Antigone Constraint.

    Science.gov (United States)

    Tuggy, David

    This paper presents a class of sentences that certain syntactic rules of English would be expected to produce, but that are not grammatical. The sentences all involve the raising of a sentential Noun Phrase (NP) and the subsequent application of some syntactic rule to that senential NP. A constraint, referred to as the Antigone Constraint, is…

  14. Theory of Constraints (TOC)

    DEFF Research Database (Denmark)

    Michelsen, Aage U.

    2004-01-01

    Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....

  15. Human choices and environmental constraints: deciphering the variability of large game procurement from Mousterian to Aurignacian times (MIS 5-3) in southwestern France

    Science.gov (United States)

    Discamps, Emmanuel; Jaubert, Jacques; Bachellerie, François

    2011-09-01

    The evolution in the selection of prey made by past humans, especially the Neandertals and the first anatomically modern humans, has been widely debated. Between Marine Isotope Stages (MIS) 5 and 3, the accuracy of absolute dating is still insufficient to precisely correlate paleoclimatic and archaeological data. It is often difficult, therefore, to estimate to what extent changes in species procurement are correlated with either climate fluctuations or deliberate cultural choices in terms of subsistence behavior. Here, the full development of archeostratigraphy and Bayesian statistical analysis of absolute dates allows the archeological and paleoclimatic chronologies to be compared. The variability in hunted fauna is investigated using multivariate statistical analysis of quantitative faunal lists of 148 assemblages from 39 archeological sequences from MIS 5 through MIS 3. Despite significant intra-technocomplex variability, it is possible to identify major shifts in the human diet during these stages. The integration of archeological data, paleoclimatic proxies and the ecological characteristics of the different species of prey shows that the shifts in large game hunting can be explained by an adaptation of the human groups to climatic fluctuations. However, even if Middle and Early Upper Paleolithic men adapted to changes in their environment and to contrasting landscapes, they ultimately belonged to the ecosystems of the past and were limited by environmental constraints.

  16. A reliable information management for real-time systems

    Energy Technology Data Exchange (ETDEWEB)

    Nishihara, Takuo; Tomita, Seiji [Nippon Telegraph and Telephone Corp., Yokosuka, Kanagawa (Japan). Information and Communication Systems Labs.

    1995-08-01

    In this paper, we propose a system configuration suitable for the hard realtime systems in which integrity and durability of information are important. On most hard real-time systems, where response time constraints are critical, the data which program access are volatile, and may be lost in case the systems are down. But for some real-time systems, the value-added intelligent network (IN) systems, e.g., integrity and durability of the stored data are very important. We propose a distributed system configuration for such hard real-time systems, comprised of service control modules and data management modules. The service control modules process transactions and responses based on deadline control, and the data management modules deal the stored data based on information recovery schemes well-restablished in fault real-time systems. (author).

  17. Holocene peatland and ice-core data constraints on the timing and magnitude of CO2emissions from past land use.

    Science.gov (United States)

    Stocker, Benjamin David; Yu, Zicheng; Massa, Charly; Joos, Fortunat

    2017-02-14

    CO 2 emissions from preindustrial land-use change (LUC) are subject to large uncertainties. Although atmospheric CO 2 records suggest only a small land carbon (C) source since 5,000 y before present (5 kyBP), the concurrent C sink by peat buildup could mask large early LUC emissions. Here, we combine updated continuous peat C reconstructions with the land C balance inferred from double deconvolution analyses of atmospheric CO 2 and [Formula: see text]C at different temporal scales to investigate the terrestrial C budget of the Holocene and the last millennium and constrain LUC emissions. LUC emissions are estimated with transient model simulations for diverging published scenarios of LU area change and shifting cultivation. Our results reveal a large terrestrial nonpeatland C source after the Mid-Holocene (66 [Formula: see text] 25 PgC at 7-5 kyBP and 115 [Formula: see text] 27 PgC at 5-3 kyBP). Despite high simulated per-capita CO 2 emissions from LUC in early phases of agricultural development, humans emerge as a driver with dominant global C cycle impacts only in the most recent three millennia. Sole anthropogenic causes for particular variations in the CO 2 record ([Formula: see text]20 ppm rise after 7 kyBP and [Formula: see text]10 ppm fall between 1500 CE and 1600 CE) are not supported. This analysis puts a strong constraint on preindustrial vs. industrial-era LUC emissions and suggests that upper-end scenarios for the extent of agricultural expansion before 1850 CE are not compatible with the C budget thereafter.

  18. A Constraint Logic Programming Framework for the Synthesis of Fault-Tolerant Schedules for Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Poulsen, Kåre Harbo; Pop, Paul; Izosimov, Viacheslav

    2007-01-01

    We present a constraint logic programming (CLP) approach for synthesis of fault-tolerant hard real-time applications on distributed heterogeneous architectures. We address time-triggered systems, where processes and messages are statically scheduled based on schedule tables. We use process re......-execution for recovering from multiple transient faults. We propose three scheduling approaches, which each present a trade-off between schedule simplicity and performance, (i) full transparency, (ii) slack sharing and (iii) conditional, and provide various degrees of transparency. We have developed a CLP framework...

  19. Deducing Electron Properties from Hard X-Ray Observations

    Science.gov (United States)

    Kontar, E. P.; Brown, J. C.; Emslie, A. G.; Hajdas, W.; Holman, G. D.; Hurford, G. J.; Kasparova, J.; Mallik, P. C. V.; Massone, A. M.; McConnell, M. L.; hide

    2011-01-01

    X-radiation from energetic electrons is the prime diagnostic of flare-accelerated electrons. The observed X-ray flux (and polarization state) is fundamentally a convolution of the cross-section for the hard X-ray emission process(es) in question with the electron distribution function, which is in turn a function of energy, direction, spatial location and time. To address the problems of particle propagation and acceleration one needs to infer as much information as possible on this electron distribution function, through a deconvolution of this fundamental relationship. This review presents recent progress toward this goal using spectroscopic, imaging and polarization measurements, primarily from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Previous conclusions regarding the energy, angular (pitch angle) and spatial distributions of energetic electrons in solar flares are critically reviewed. We discuss the role and the observational evidence of several radiation processes: free-free electron-ion, free-free electron-electron, free-bound electron-ion, photoelectric absorption and Compton backscatter (albedo), using both spectroscopic and imaging techniques. This unprecedented quality of data allows for the first time inference of the angular distributions of the X-ray-emitting electrons and improved model-independent inference of electron energy spectra and emission measures of thermal plasma. Moreover, imaging spectroscopy has revealed hitherto unknown details of solar flare morphology and detailed spectroscopy of coronal, footpoint and extended sources in flaring regions. Additional attempts to measure hard X-ray polarization were not sufficient to put constraints on the degree of anisotropy of electrons, but point to the importance of obtaining good quality polarization data in the future.

  20. Constraint-based reachability

    Directory of Open Access Journals (Sweden)

    Arnaud Gotlieb

    2013-02-01

    Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.

  1. Modified NSGA-II for Solving Continuous Berth Allocation Problem: Using Multiobjective Constraint-Handling Strategy.

    Science.gov (United States)

    Ji, Bin; Yuan, Xiaohui; Yuan, Yanbin

    2017-09-01

    Continuous berth allocation problem (BAPC) is a major optimization problem in transportation engineering. It mainly aims at minimizing the port stay time of ships by optimally scheduling ships to the berthing areas along quays while satisfying several practical constraints. Most of the previous literatures handle the BAPC by heuristics with different constraint handling strategies as it is proved NP-hard. In this paper, we transform the constrained single-objective BAPC (SBAPC) model into unconstrained multiobjective BAPC (MBAPC) model by converting the constraint violation as another objective, which is known as the multiobjective optimization (MOO) constraint handling technique. Then a bias selection modified non-dominated sorting genetic algorithm II (MNSGA-II) is proposed to optimize the MBAPC, in which an archive is designed as an efficient complementary mechanism to provide search bias toward the feasible solution. Finally, the proposed MBAPC model and the MNSGA-II approach are tested on instances from literature and generation. We compared the results obtained by MNSGA-II with other MOO algorithms under the MBAPC model and the results obtained by single-objective oriented methods under the SBAPC model. The comparison shows the feasibility of the MBAPC model and the advantages of the MNSGA-II algorithm.

  2. Aggregating energy flexibilities under constraints

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Pedersen, Torben Bach; Abello, Alberto

    2016-01-01

    The flexibility of individual energy prosumers (producers and/or consumers) has drawn a lot of attention in recent years. Aggregation of such flexibilities provides prosumers with the opportunity to directly participate in the energy market and at the same time reduces the complexity of scheduling...... the energy units. However, aggregated flexibility should support normal grid operation. In this paper, we build on the flex-offer (FO) concept to model the inherent flexibility of a prosumer (e.g., a single flexible consumption device such as a clothes washer). An FO captures flexibility in both time...... and amount dimensions. We define the problem of aggregating FOs taking into account grid power constraints. We also propose two constraint-based aggregation techniques that efficiently aggregate FOs while retaining flexibility. We show through a comprehensive evaluation that our techniques, in contrast...

  3. Managing Restaurant Tables using Constraints

    Science.gov (United States)

    Vidotto, Alfio; Brown, Kenneth N.; Beck, J. Christopher

    Restaurant table management can have significant impact on both profitability and the customer experience. The core of the issue is a complex dynamic combinatorial problem. We show how to model the problem as constraint satisfaction, with extensions which generate flexible seating plans and which maintain stability when changes occur. We describe an implemented system which provides advice to users in real time. The system is currently being evaluated in a restaurant environment.

  4. Infinite hard-sphere system

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, R.K.

    1975-09-01

    The time-evolution for the system of infinitely many particles in space interacting by a hard-sphere potential is constructed. Examples abound of configurations of the infinite system having more than one solution to the Newtonian equations of motion. A regularity condition is imposed on the solutions sought, which limits the growth of velocities and of the length of chains of particles close together as absolute value x ..-->.. infinity; it is proven that through any point of the phase space there passes at most one regular solution. Every point in a subset X bar of the phase space X is the initial point of a regular solution which is defined for all time. The subset X bar is of full measure for every Gibbs state and is invariant under the one-parameter group T/sup t/ of shifts along solution trajectories. Moreover, the flow T/sup t/ leaves every Gibbs state invariant. The solutions constructed are limits, as R ..-->.. infinity, of motions in which particles inside the sphere of radius R are elastically reflected from its boundary while those outside remain fixed. For this reason, one also studies the motion of finite systems. For finitely many hard-sphere particles in a region of space with piecewise smooth boundary, the set of points of the phase space through which solutions exist for all time without triple or grazing collisions, are of full Lebesgue measure and are residual in the sense of Baire. Liouville's Theorem holds for the one-parameter group of shift-transformations T/sup t/. Finally, we give examples in which a single billiard moving in the plane is reflected infinitely often from a boundary curve in finite time, and necessary conditions for such singularities to occur are established.

  5. Revisiting the definition of local hardness and hardness kernel.

    Science.gov (United States)

    Polanco-Ramírez, Carlos A; Franco-Pérez, Marco; Carmona-Espíndola, Javier; Gázquez, José L; Ayers, Paul W

    2017-05-17

    An analysis of the hardness kernel and local hardness is performed to propose new definitions for these quantities that follow a similar pattern to the one that characterizes the quantities associated with softness, that is, we have derived new definitions for which the integral of the hardness kernel over the whole space of one of the variables leads to local hardness, and the integral of local hardness over the whole space leads to global hardness. A basic aspect of the present approach is that global hardness keeps its identity as the second derivative of energy with respect to the number of electrons. Local hardness thus obtained depends on the first and second derivatives of energy and electron density with respect to the number of electrons. When these derivatives are approximated by a smooth quadratic interpolation of energy, the expression for local hardness reduces to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba. However, when one combines the first directional derivatives with smooth second derivatives one finds additional terms that allow one to differentiate local hardness for electrophilic attack from the one for nucleophilic attack. Numerical results related to electrophilic attacks on substituted pyridines, substituted benzenes and substituted ethenes are presented to show the overall performance of the new definition.

  6. Constraints and Creativity in NPD - Testing the Impact of 'Late Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Valgeirsdóttir, Dagný

    The aim of the presented work is to investigate how the timing of project constraints can influence the creativity of the output in New Product Development (NPD) projects. When seeking to produce a creative output, is it beneficial to know all constraints when initiating a project, or will constr......, in the presented setup no negative impact of adding radically new constraints during a project was found, highlighting for managers that it is not crucial to a project’s creative output to have all constraints from the beginning.......The aim of the presented work is to investigate how the timing of project constraints can influence the creativity of the output in New Product Development (NPD) projects. When seeking to produce a creative output, is it beneficial to know all constraints when initiating a project......, or will constraints introduced throughout a project potentially lead to a more creative output? While the relationship between constraints and creativity is fairly well studied, the question of how introducing constraints late in a project can influence creativity is still unanswered. A single factor, two level...

  7. Real-Time Scheduling in Heterogeneous Systems Considering Cache Reload Time Using Genetic Algorithms

    Science.gov (United States)

    Miryani, Mohammad Reza; Naghibzadeh, Mahmoud

    Since optimal assignment of tasks in a multiprocessor system is, in almost all practical cases, an NP-hard problem, in recent years some algorithms based on genetic algorithms have been proposed. Some of these algorithms have considered real-time applications with multiple objectives, total tardiness, completion time, etc. Here, we propose a suboptimal static scheduler of nonpreemptable tasks in hard real-time heterogeneous multiprocessor systems considering time constraints and cache reload time. The approach makes use of genetic algorithm to minimize total completion time and number of processors used, simultaneously. One important issue which makes this research different from previous ones is cache reload time. The method is implemented and the results are compared against a similar method.

  8. Dynamic design method for deep hard rock tunnels and its application

    Directory of Open Access Journals (Sweden)

    Xia-Ting Feng

    2016-08-01

    Full Text Available Numerous deep underground projects have been designed and constructed in China, which are beyond the current specifications in terms of scale and construction difficulty. The severe failure problems induced by high in situ stress, such as rockburst, spalling, damage of deep surrounding rocks, and time-dependent damage, were observed during construction of these projects. To address these problems, the dynamic design method for deep hard rock tunnels is proposed based on the disintegration process of surrounding rocks using associated dynamic control theories and technologies. Seven steps are basically employed: (i determination of design objective, (ii characteristics of site, rock mass and project, and identification of constraint conditions, (iii selection or development of global design strategy, (iv determination of modeling method and software, (v preliminary design, (vi comprehensive integrated method and dynamic feedback analysis, and (vii final design. This dynamic method was applied to the construction of the headrace tunnels at Jinping II hydropower station. The key technical issues encountered during the construction of deep hard rock tunnels, such as in situ stress distribution along the tunnels, mechanical properties and constitutive model of deep hard rocks, determination of mechanical parameters of surrounding rocks, stability evaluation of surrounding rocks, and optimization design of rock support and lining, have been adequately addressed. The proposed method and its application can provide guidance for deep underground projects characterized with similar geological conditions.

  9. Variation in the mantle sources of the northern Izu arc with time and space — Constraints from high-precision Pb isotopes

    Science.gov (United States)

    Ishizuka, Osamu; Taylor, Rex N.; Milton, J. Andy; Nesbitt, Robert W.; Yuasa, Makoto; Sakamoto, Izumi

    2006-09-01

    differing mantle sources depending on the northward position within the arc. This variation in mantle wedge composition is seen to continue into the central part of the arc [Ishizuka, O., Taylor, R.N., Milton, J.A., Nesbitt, R.W., Fluid mantle interaction in an intra-oceanic arc: constraints from high-precision Pb isotopes, Earth Planet. Sci. Lett. 211 (2003a) 221 236]. The observed along-arc isotopic variation can be explained by the presence of two mantle components; a MORB source observed in the back-arc basins of the Philippine Sea Plate (e.g. [Hickey-Vargas, R., Origin of the Indian Ocean-type isotopic signature in basalts from Philippine Sea Plate spreading centers: An assessment of local versus large-scale processes, J. Geophys. Res. 103 (1998a) 20963 20979]) and a more Pacific MORB-like source. In the northern part of the Izu Bonin arc, Miocene to Pliocene volcanism was active over a much wider back-arc region than present, and these lavas show the greatest influence of sediment melt generated at slab depths of > 250 km. However, in the Quaternary active volcanism was constrained to the vicinity of the volcanic front. This Quaternary magmatism can be related to the release of fluid from the slab at relatively shallow depths (110 200 km). These spatial and temporal chemical variations could be related to either the change of the angle of subducting Pacific Plate and/or changes in the regional stress regime (e.g. resulting from the collision of the Izu Bonin arc with the Honshu arc or in association with initiation of rifting in the south).

  10. A compendium of chameleon constraints

    Science.gov (United States)

    Burrage, Clare; Sakstein, Jeremy

    2016-11-01

    The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candidate and also arises in f(R) theories of gravity. Whilst the chameleon is designed to avoid historical searches for fifth-forces it is not unobservable and much effort has gone into identifying the best observables and experiments to detect it. These results are not always presented for the same models or in the same language, a particular problem when comparing astrophysical and laboratory searches making it difficult to understand what regions of parameter space remain. Here we present combined constraints on the chameleon model from astrophysical and laboratory searches for the first time and identify the remaining windows of parameter space. We discuss the implications for cosmological chameleon searches and future small-scale probes.

  11. Hardness of approximation for Knapsack problems

    NARCIS (Netherlands)

    Buhrman, H.; Loff, B.; Torenvliet, L.

    2015-01-01

    We show various hardness results for knapsack and related problems; in particular we will show that unless the Exponential-Time Hypothesis is false, subset-sum cannot be approximated any better than with an FPTAS. We also provide new unconditional lower bounds for approximating knapsack in Ketan

  12. Hardness of approximation for strip packing

    DEFF Research Database (Denmark)

    Adamaszek, Anna Maria; Kociumaka, Tomasz; Pilipczuk, Marcin

    2017-01-01

    -dimensional knapsack. In this article, we answer this question in negative by proving that it is NP-hard to approximate strip packing within a factor better than 12/11, even when restricted to polynomially bounded input data. In particular, this shows that the strip packing problem admits no quasi-polynomial time...

  13. Locating phase transitions in computationally hard problems

    Indian Academy of Sciences (India)

    Treating the computational time, value and utility functions involved in the search results in analogy with quantities in statistical physics, we indicate how the onset of a computationally hard regime can be detected and the transit to higher quality solutions be quantified by an appropriate response function. The existence of a ...

  14. Apatite fission track and (U-Th)/He dating of teschenite intrusions gives time constraints on accretionary processes and development of planation surfaces in the Outer Western Carpathians

    Energy Technology Data Exchange (ETDEWEB)

    Danisik, Martin; Frisch, Wolfgang [Tuebingen Univ. (Germany). Inst. of Geosciences; Panek, Tomas [Ostrava Univ. (Czech Republic). Dept. of Physical Geography and Geoecology; Matysek, Dalibor [Technical Univ. of Ostrava (Czech Republic). Dept. of Geological Engineering; Dunkl, Istvan [Geoscience Center Goettingen (Germany). Sedimentology and Environmental Geology

    2008-09-15

    The age of planation surfaces in the Podbeskydska pahorkatina Upland in the Outer Western Carpathians (OWC, Czech Republic) is constrained by low-temperature thermochronological dating methods for the first time. Our apatite fission track and apatite (U-Th)/He data measured on teschenite intrusions show that planation surfaces in the study area formed in post-Pannonian time (>7.1 Ma) and are therefore younger than traditionally believed. This contradicts the classical concepts, which stipulate that a large regional planation surface of Pannonian age (the so-called ''midmountain level'') developed in the whole Western Carpathians. Geodynamic implications of our data are the following: (i) the investigated Tesin and Godula nappes of the OWC were buried and thermally overprinted in the accretionary wedge in different ways, and consequently experienced different cooling histories. This indicates a dynamic basin setting with an active accretionary process in a subduction zone; (ii) accretionary processes in the OWC were active already during Late Eocene times. (orig.)

  15. Time-scales of assembly and thermal history of a composite felsic pluton: constraints from the Emerald Lake area, northern Canadian Cordillera, Yukon

    Science.gov (United States)

    Coulson, Ian M.; Villeneuve, Mike E.; Dipple, Gregory M.; Duncan, Robert A.; Russell, James K.; Mortensen, James K.

    2002-05-01

    Knowledge of the time-scales of emplacement and thermal history during assembly of composite felsic plutons in the shallow crust are critical to deciphering the processes of crustal growth and magma chamber development. Detailed petrological and chemical study of the mid-Cretaceous, composite Emerald Lake pluton, from the northern Canadian Cordillera, Yukon Territory, coupled with U-Pb and 40Ar/ 39Ar geochronology, indicates that this pluton was intruded as a series of magmatic pulses. Intrusion of these pulses produced a strong petrological zonation from augite syenite, hornblende quartz syenite and monzonite, to biotite granite. Our data further indicate that multiple phases were emplaced and cooled to below the mineral closure temperatures over a time-scale on the order of the resolution of the 40Ar/ 39Ar technique (˜1 Myr), and that emplacement occurred at 94.3 Ma. Simple thermal modelling and heat conduction calculations were used to further constrain the temporal relationships within the intrusion. These calculations are consistent with the geochronology and show that emplacement and cooling were complete in less than 100 kyr and probably 70±5 kyr. These results demonstrate that production, transport and emplacement of the different phases of the Emerald Lake pluton occurred essentially simultaneously, and that these processes must also have been closely related in time and space. By analogy, these results provide insights into the assembly and petrogenesis of other complex intrusions and ultimately lead to an understanding of the processes involved in crustal development.

  16. Janka hardness using nonstandard specimens

    Science.gov (United States)

    David W. Green; Marshall Begel; William Nelson

    2006-01-01

    Janka hardness determined on 1.5- by 3.5-in. specimens (2×4s) was found to be equivalent to that determined using the 2- by 2-in. specimen specified in ASTM D 143. Data are presented on the relationship between Janka hardness and the strength of clear wood. Analysis of historical data determined using standard specimens indicated no difference between side hardness...

  17. Time Constraints on Soil Evolution from Uranium-series Isotopes in the South-eastern Australian Highlands: Evidences for a Coupling Between Soil Erosion and Production

    Science.gov (United States)

    Puthiyaveetil Othayoth, S.; Dosseto, A.; Hesse, P. P.; Handley, H. K.

    2011-12-01

    The evolution of soil resources (steady-state, aggradation or degradation) is determined by the balance between soil production and denudation rates. The uranium-series isotopic composition of four soil profiles from Frogs Hollow, a location in the upper catchment area of the Murrumbidgee River in southeastern Australia, has been determined to constrain the soil production rate in this region. The results are compared with previous estimates of soil residence time at this site, estimated from cosmogenic radionuclides and soil elemental chemistry data. Soil is increasingly weathered from bottom to top, which is evident from the decrease in (234U/238U) ratios and increase in relative quartz content with decreasing soil depth. The observed variations in mineralogy and geochemistry between the four soil profiles reflect differences in the degree of weathering. Sequential leaching was conducted to assess how uranium-series isotopes are distributed between primary and secondary minerals. Leached and unleached aliquots show similar mineralogy with minor variation in the relative mineral abundances whereas the elemental and isotopic compositions of uranium and thorium show notable differences. The unleached samples show more systematic variations in uranium-series isotopic compositions with depth when compared to leached samples. Soil residence times are calculated by modeling soil uranium-series isotopic composition using the model from (Dosseto et al., 2008). Inferred values vary from 3 to 30 kyr for profiles F1 (unleached aliquots) and F2. A negative correlation is observed between muscovite abundance and calculated soil residence times. The slope of this correlation is similar for different soil profiles and for both leached and unleached aliquots. Thus, we were able to apply this relationship to profiles where the residence time could not be calculated due to scatter in U-series isotope compositions. The inferred soil residence times range from 3 to 33 kyr for leached

  18. Constraints in Genetic Programming

    Science.gov (United States)

    Janikow, Cezary Z.

    1996-01-01

    Genetic programming refers to a class of genetic algorithms utilizing generic representation in the form of program trees. For a particular application, one needs to provide the set of functions, whose compositions determine the space of program structures being evolved, and the set of terminals, which determine the space of specific instances of those programs. The algorithm searches the space for the best program for a given problem, applying evolutionary mechanisms borrowed from nature. Genetic algorithms have shown great capabilities in approximately solving optimization problems which could not be approximated or solved with other methods. Genetic programming extends their capabilities to deal with a broader variety of problems. However, it also extends the size of the search space, which often becomes too large to be effectively searched even by evolutionary methods. Therefore, our objective is to utilize problem constraints, if such can be identified, to restrict this space. In this publication, we propose a generic constraint specification language, powerful enough for a broad class of problem constraints. This language has two elements -- one reduces only the number of program instances, the other reduces both the space of program structures as well as their instances. With this language, we define the minimal set of complete constraints, and a set of operators guaranteeing offspring validity from valid parents. We also show that these operators are not less efficient than the standard genetic programming operators if one preprocesses the constraints - the necessary mechanisms are identified.

  19. 2TB hard disk drive

    CERN Multimedia

    This particular object was used up until 2012 in the Data Centre. It slots into one of the Disk Server trays. Hard disks were invented in the 1950s. They started as large disks up to 20 inches in diameter holding just a few megabytes (link is external). They were originally called "fixed disks" or "Winchesters" (a code name used for a popular IBM product). They later became known as "hard disks" to distinguish them from "floppy disks (link is external)." Hard disks have a hard platter that holds the magnetic medium, as opposed to the flexible plastic film found in tapes and floppies.

  20. Synchronized sweep algorithms for scalable scheduling constraints

    OpenAIRE

    Letort, Arnaud; Carlsson, Mats; Beldiceanu, Nicolas

    2013-01-01

    This report introduces a family of synchronized sweep based filtering algorithms for handling scheduling problems involving resource and precedence constraints. The key idea is to filter all constraints of a scheduling problem in a synchronized way in order to scale better. In addition to normal filtering mode, the algorithms can run in greedy mode, in which case they perform a greedy assignment of start and end times. The filtering mode achieves a significant speed-up over ...

  1. Neutrino Analysis of the September 2010 Crab Nebula Flare and Time-integrated Constraints on Neutrino Emission From the Crab Using IceCube

    Science.gov (United States)

    Stamatikos, M.; Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguliar, J. A.; Ahlers, M.; Altmann, D.; Andeen, K.; Auffenberg, J.; hide

    2012-01-01

    We present the results for a search of high-energy muon neutrinos with the IceCube detector in coincidence with the Crab nebula flare reported on September 2010 by various experiments. Due to the unusual flaring state of the otherwise steady source we performed a prompt analysis of the 79-string configuration data to search for neutrinos that might be emitted along with the observed gamma-rays. We performed two different and complementary data selections of neutrino events in the time window of 10 days around the flare. One event selection is optimized for discovery of E(sub nu)(sup -2) neutrino spectrum typical of 1st order Fermi acceleration. A similar event selection has also been applied to the 40-string data to derive the time-integrated limits to the neutrino emission from the Crab [35]. The other event selection was optimized for discovery of neutrino spectra with softer spectral index and TeV energy cut-offs as observed for various galactic sources in gamma-rays. The 90% CL best upper limits on the Crab flux during the 10 day flare are 4.73 x 10(exp -11) per square centimeter per second TeV (sup -1) for an E(sub nu) (sup -2) neutrino spectrum and 2.50 x 10(exp -10) per square centimeter per second TeV(sup -1) for a softer neutrino spectra of E(sub nu)(sup -2.7), as indicated by Fermi measurements during the flare. IceCube has also set a time-integrated limit on the neutrino emission of the Crab using 375.5 days of livetime of the 40-string configuration data. This limit is compared to existing models of neutrino production from the Crab and its impact on astrophysical parameters is discussed. The most optimistic predictions of some models are already rejected by the IceCube neutrino telescope with more than 90% CL.

  2. Biophysical modeling of brain tumor progression: From unconditionally stable explicit time integration to an inverse problem with parabolic PDE constraints for model calibration.

    Science.gov (United States)

    Mang, Andreas; Toma, Alina; Schuetz, Tina A; Becker, Stefan; Eckey, Thomas; Mohr, Christian; Petersen, Dirk; Buzug, Thorsten M

    2012-07-01

    A novel unconditionally stable, explicit numerical method is introduced to the field of modeling brain cancer progression on a tissue level together with an inverse problem (IP) based on optimal control theory that allows for automated model calibration with respect to observations in clinical imaging data. Biophysical models of cancer progression on a tissue level are in general based on the assumption that the spatiotemporal spread of cancerous cells is determined by cell division and net migration. These processes are typically described in terms of a parabolic partial differential equation (PDE). In the present work a parallelized implementation of an unconditionally stable, explicit Euler (EE(⋆) ) time integration method for the solution of this PDE is detailed. The key idea of the discussed EE(⋆) method is to relax the strong stability requirement on the spectral radius of the coefficient matrix by introducing a subdivision regime for a given outer time step. The performance is related to common implicit numerical methods. To quantify the numerical error, a simplified model that has a closed form solution is considered. To allow for a systematic, phenomenological validation a novel approach for automated model calibration on the basis of observations in medical imaging data is developed. The resulting IP is based on optimal control theory and manifests as a large scale, PDE constrained optimization problem. The numerical error of the EE(⋆) method is at the order of standard implicit numerical methods. The computing times are well below those obtained for implicit methods and by that demonstrate efficiency. Qualitative and quantitative analysis in 12 patients demonstrates that the obtained results are in strong agreement with observations in medical imaging data. Rating simulation success in terms of the mean overlap between model predictions and manual expert segmentations yields a success rate of 75% (9 out of 12 patients). The discussed EE(⋆) method

  3. Measurement of time-dependent CP asymmetries and constraints on sin(2beta+gamma) with partial reconstruction of B0-->D*-/+pi+/- decays.

    Science.gov (United States)

    Aubert, B; Barate, R; Boutigny, D; Couderc, F; Gaillard, J-M; Hicheur, A; Karyotakis, Y; Lees, J P; Robbe, P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; LeClerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Romosan, A; Ronan, M T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Knowles, D J; Morgan, S E; Penny, R C; Watson, A T; Watson, N K; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmuecker, H; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Mackay, C; Wilson, F F; Abe, K; Cuhadar-Donszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; McKemey, A K; Teodorescu, L; Blinov, V E; Bukin, A D; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Gary, J W; Layter, J; Shen, B C; Wang, K; del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, Sh; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Beringer, J; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Spradlin, P; Turri, M; Walkowiak, W; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Erwin, R J; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Roy, J; Smith, J G; van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Soffer, A; Toki, W H; Wilson, R J; Zhang, J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Dubitzky, R S; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Schubert, J; Schubert, K R; Schwierz, R; Spaan, B; Wilden, L; Bernard, D; Bonneaud, G R; Brochard, F; Cohen-Tanugi, J; Grenier, P; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Khan, A; Lavin, D; Muheim, F; Playfer, S; Swain, J E; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Falciai, D; Finocchiaro, G; Patteri, P; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Morii, M; Won, E; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Eschrich, I; Gaillard, J R; Morton, G W; Nash, J A; Taylor, G P; Grenier, G J; Lee, S-J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Diberder, F Le; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Brigljević, V; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, E; Gamet, R; Kay, M; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Harrison, P F; Shorthouse, H W; Vidal, P B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; George, S; Green, M G; Kurup, A; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Jackson, F; Lafferty, G D; Lyon, A J; Weatherall, J H; Williams, J C; Farbin, A; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Cote-Ahern, D; Taras, P; Nicholson, H; Cartaro, C; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; LoSecco, J M; Gabriel, T A; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; de la Vaissière, Ch; Del Buono, L; Hamon, O; John, M J J; Leruste, Ph; Ocariz, J; Pivk, M; Roos, L; Stark, J; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Anulli, F; Biasini, M; Peruzzi, I M; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Del Gamba, V; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martinez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lu, C; Miftakov, V; Olsen, J; Smith, A J S; Tanaka, H A; Varnes, E W; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; SafaiTehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Geddes, N I; Gopal, G P; Olaiya, E O; Xella, S M; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P-F; Hamel de Monchenault, G; Kozanecki, W; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yeche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Convery, M R; Cristinziani, M; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Elsen, E E; Field, R C; Glanzman, T; Gowdy, S J; Grauges-Pous, E; Hadig, T; Halyo, V; Hryn'ova, T; Innes, W R; Jessop, C P; Kelsey, M H; Kim, P; Kocian, M L; Langenegger, U; Leith, D W G S; Libby, J; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Va'vra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wright, D H; Young, C C; Burchat, P R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihalyi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; von Wimmersperg-Toeller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H

    2004-06-25

    We present a measurement of time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D(*-/+)pi(+/-), using approximately 82x10(6) BBmacr; events recorded by the BABAR experiment at the PEP-II e(+)e(-) storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum pi(+/-) from the B decay and the low-momentum pi(-/+) from the D(*-/+) decay are used. We measure the amplitude of the asymmetry to be -0.063+/-0.024(stat)+/-0.014(syst) and compute bounds on |sin((2beta+gamma)|.

  4. High-precision U-Pb zircon geochronological constraints on the End-Triassic Mass Extinction, the late Triassic Astronomical Time Scale and geochemical evolution of CAMP magmatism

    Science.gov (United States)

    Blackburn, T. J.; Olsen, P. E.; Bowring, S. A.; McLean, N. M.; Kent, D. V.; Puffer, J. H.; McHone, G.; Rasbury, T.

    2012-12-01

    Mass extinction events that punctuate Earth's history have had a large influence on the evolution, diversity and composition of our planet's biosphere. The approximate temporal coincidence between the five major extinction events over the last 542 million years and the eruption of Large Igneous Provinces (LIPs) has led to the speculation that climate and environmental perturbations generated by the emplacement of a large volume of magma in a short period of time triggered each global biologic crisis. Establishing a causal link between extinction and the onset and tempo of LIP eruption has proved difficult because of the geographic separation between LIP volcanic deposits and stratigraphic sequences preserving evidence of the extinction. In most cases, the uncertainties on available radioisotopic dates used to correlate between geographically separated study areas often exceed the duration of both the extinction interval and LIP volcanism by an order of magnitude. The "end-Triassic extinction" (ETE) is one of the "big five" and is characterized by the disappearance of several terrestrial and marine species and dominance of Dinosaurs for the next 134 million years. Speculation on the cause has centered on massive climate perturbations thought to accompany the eruption of flood basalts related to the Central Atlantic Magmatic Province (CAMP), the most aerially extensive and volumetrically one of the largest LIPs on Earth. Despite an approximate temporal coincidence between extinction and volcanism, there lacks evidence placing the eruption of CAMP prior to or at the initiation of the extinction. Estimates of the timing and/or duration of CAMP volcanism provided by astrochronology and Ar-Ar geochronology differ by an order of magnitude, precluding high-precision tests of the relationship between LIP volcanism and the mass extinction, the causes of which are dependent upon the rate of magma eruption. Here we present high precision zircon U-Pb ID-TIMS geochronologic data

  5. Timing of exhumation of the Ereendavaa metamorphic core complex (north-eastern Mongolia) - U-Pb and 40Ar/39Ar constraints

    Science.gov (United States)

    Daoudene, Yannick; Ruffet, Gilles; Cocherie, Alain; Ledru, Patrick; Gapais, Denis

    2013-01-01

    The occurrence of numerous NE-SW trending rift basins that locally bound metamorphic core complexes in Transbaikalia, northern Mongolia and north-eastern China indicates that the eastern domain of the Central Asian Orogenic Belt was affected by a large-scale NW-SE extensional tectonic event during late Jurassic to early Cretaceous times. Available geochronological information about the formation of metamorphic core complexes in the region define partly synchronous periods in Transbaikalia (134-121 Ma) and North China (136-110 Ma) suggesting dome exhumation during the early Cretaceous. In north-eastern Mongolia, the Ereendavaa Range, lined by the Onon Shear Zone, was recently interpreted as one of these metamorphic core complexes, of late Jurassic to early Cretaceous age, on the basis of U-Pb zircons data from two synkinematic pegmatite dykes. However, this wide time range remains to be discussed. The present work constrains the tectono-thermal evolution of the range by providing new MC-ICP-MS U-Pb zircons ages from pegmatite dykes and metamorphic igneous rocks, and mica and amphibole 40Ar/39Ar laser step-heating ages from metamorphic and magmatic rocks that crop out within the range. The results show that (1) the Ereendavaa range was the locus of a widespread magmatic activity prior to its exhumation from late Jurassic times, (2) cooling of the range began at least at 137.9 ± 0.3 Ma as revealed by a 40Ar/39Ar plateau ages obtained from an hornblende sampled within the range core, and (3) exhumation along the Onon Shear Zone occurred from 130.3 ± 1.9 Ma down to 124.8 ± 0.3 Ma, as shown by ages of most of micas and amphiboles from the Shear zone. These more accurate ages are consistent with metamorphic core complex ages from adjacent areas. Furthermore, they argue for an extensional dynamic paroxysm at the scale of eastern Asia during a narrow time range in the early Cretaceous between ca. 130 Ma and ca. 120 Ma.

  6. Using soft constraints to guide users in flexible business process management systems

    DEFF Research Database (Denmark)

    Stefansen, Christian; Borch, Signe Ellegård

    2008-01-01

    Current Business Process Management Systems (BPMS) allow designers to specify processes in highly expressive languages supporting numerous control flow constructs, exceptions, complex predicates, etc., but process specifications are expressed in terms of hard constraints, and this leads to an unf......Current Business Process Management Systems (BPMS) allow designers to specify processes in highly expressive languages supporting numerous control flow constructs, exceptions, complex predicates, etc., but process specifications are expressed in terms of hard constraints, and this leads...... to an unfortunate trade off: information about preferred practices must either be abandoned or promoted to hard constraints. If abandoned, the BPMS cannot guide its users; if promoted to hard constraints, it becomes a hindrance when unanticipated deviations occur. Soft constraints can make this trade-off less...... painful. Soft constraints specify what rules can be violated and by how much. With soft constraints, the BPMS knows what deviations it can permit, and it can guide the user through the process. The BPMS should allow designers to easily specify soft goals and allow its users to immediately see...

  7. New constraints on the timing of flexural deformation along the northern Australian margin: Implications for arc-continent collision and the development of the Timor Trough

    Science.gov (United States)

    Saqab, Muhammad Mudasar; Bourget, Julien; Trotter, Julie; Keep, Myra

    2017-01-01

    Numerous extensional faults offset the passive margin strata of the northern Bonaparte Basin. This extensional deformation has been attributed to lithospheric flexure of the descending Australian Plate, in an overall convergence setting. Here we use an extensive 2D and 3D seismic dataset calibrated with well biostratigraphy and strontium (Sr) isotope age data to constrain the timing of deformation along the northern Australian margin during the Neogene. Analysis of fault throw and differential thickness variations give new insights on the propagation and slip history of the faults. Along-dip throw profiles exhibit 'D' shape distributions, skewed towards the top. Positive throw gradients above the throw maxima, coinciding with intervals of growth strata, indicate multiphase fault activity. Results indicate that post-rift extensional deformation initiated during the latest Miocene (ca. 6 Ma). The development of the modern Timor Trough (as a foreland basin) and Cartier Trough also commenced during this period. A second episode of increased tectonic activity occurred around the Pliocene-Quaternary boundary (ca. 3 Ma), and the deformation continued intermittently to the present-day. These new results are in agreement with the timing of initiation of collision between the Australian Plate and the Banda Arc and uplift of the Timor Island, recently derived from stratigraphic analysis in Timor. These regional tectonic events have profoundly affected the paleogeography of the Timor Sea and may explain major changes in oceanic circulation and climate during the Neogene.

  8. The first-order theory of ordering constraints over feature trees

    Directory of Open Access Journals (Sweden)

    Martin Müller

    2001-12-01

    Full Text Available The system FT ≤ of ordering constraints over feature trees has been introduced as an extension of the system FT of equality constraints over feature trees. We investigate the first-order theory of FT ≤ and its fragments in detail, both over finite trees and over possibly infinite trees. We prove that the first-order theory of FT ≤ is undecidable, in contrast to the first-order theory of FT which is well-known to be decidable. We show that the entailment problem of FT ≤ with existential quantification is PSPACE-complete. So far, this problem has been shown decidable, coNP-hard in case of finite trees, PSPACE-hard in case of arbitrary trees, and cubic time when restricted to quantifier-free entailment judgments. To show PSPACE-completeness, we show that the entailment problem of FT ≤ with existential quantification is equivalent to the inclusion problem of non-deterministic finite automata.

  9. Psychological constraints on egalitarianism

    DEFF Research Database (Denmark)

    Kasperbauer, Tyler Joshua

    2015-01-01

    Debates over egalitarianism for the most part are not concerned with constraints on achieving an egalitarian society, beyond discussions of the deficiencies of egalitarian theory itself. This paper looks beyond objections to egalitarianism as such and investigates the relevant psychological...... philosophy, which aim to construct moral goals with current social and political constraints in mind, to argue that human psychology must be part of a non-ideal theory of egalitarianism. The descriptive thesis holds that the most fundamental psychological challenge to egalitarian ideals comes from what...... processes motivating people to resist various aspects of egalitarianism. I argue for two theses, one normative and one descriptive. The normative thesis holds that egalitarians must take psychological constraints into account when constructing egalitarian ideals. I draw from non-ideal theories in political...

  10. Random Constraint Satisfaction Problems

    Directory of Open Access Journals (Sweden)

    Amin Coja-Oghlan

    2009-11-01

    Full Text Available Random instances of constraint satisfaction problems such as k-SAT provide challenging benchmarks. If there are m constraints over n variables there is typically a large range of densities r=m/n where solutions are known to exist with probability close to one due to non-constructive arguments. However, no algorithms are known to find solutions efficiently with a non-vanishing probability at even much lower densities. This fact appears to be related to a phase transition in the set of all solutions. The goal of this extended abstract is to provide a perspective on this phenomenon, and on the computational challenge that it poses.

  11. Measurement of time-dependent CP asymmetries in B0-->D(*)+/-pi-/+ decays and constraints on sin(2beta+gamma).

    Science.gov (United States)

    Aubert, B; Barate, R; Boutigny, D; Gaillard, J-M; Hicheur, A; Karyotakis, Y; Lees, J P; Robbe, P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; LeClerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Romosan, A; Ronan, M T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Knowles, D J; Morgan, S E; Penny, R C; Watson, A T; Watson, N K; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmuecker, H; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Mackay, C; Wilson, F F; Abe, K; Cuhadar-Donszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; McKemey, A K; Teodorescu, L; Blinov, V E; Bukin, A D; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Gary, J W; Layter, J; Shen, B C; Wang, K; del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, Sh; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Kuznetsova, N; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Beringer, J; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Turri, M; Walkowiak, W; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Erwin, R J; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Roy, J; Smith, J G; van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Soffer, A; Toki, W H; Wilson, R J; Zhang, J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Dubitzky, R S; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Schubert, J; Schubert, K R; Schwierz, R; Spaan, B; Wilden, L; Bernard, D; Bonneaud, G R; Brochard, F; Cohen-Tanugi, J; Grenier, P; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Khan, A; Lavin, D; Muheim, F; Playfer, S; Swain, J E; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Anulli, F; Baldini-Ferroli, R; Biasini, M; Calcaterra, A; de Sangro, R; Falciai, D; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Pioppi, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Morii, M; Won, E; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Eschrich, I; Gaillard, J R; Morton, G W; Nash, J A; Sanders, P; Taylor, G P; Grenier, G J; Lee, S-J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Brigljević, V; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, E; Gamet, R; Kay, M; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Harrison, P F; Shorthouse, H W; Vidal, P B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; George, S; Green, M G; Kurup, A; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Jackson, F; Lafferty, G D; Lyon, A J; Weatherall, J H; Williams, J C; Farbin, A; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Cote-Ahern, D; Taras, P; Nicholson, H; Cartaro, C; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; LoSecco, J M; Gabriel, T A; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Wong, Q K; Brau, J; Frey, R; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; de la Vaissière, Ch; Del Buono, L; Hamon, O; John, M J J; Leruste, Ph; Ocariz, J; Pivk, M; Roos, L; Stark, J; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Del Gamba, V; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martinez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lu, C; Miftakov, V; Olsen, J; Smith, A J S; Tanaka, H A; Varnes, E W; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Tehrani, F Safai; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Geddes, N I; Gopal, G P; Olaiya, E O; Xella, S M; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P-F; Hamel de Monchenault, G; Kozanecki, W; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yeche, Ch; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Convery, M R; Coupal, D P; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Grauges-Pous, E; Hadig, T; Halyo, V; Hryn'ova, T; Innes, W R; Jessop, C P; Kelsey, M H; Kim, P; Kocian, M L; Langenegger, U; Leith, D W G S; Libby, J; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Va'vra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wright, D H; Young, C C; Burchat, P R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihalyi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; von Wimmersperg-Toeller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H

    2004-06-25

    We present a measurement of CP-violating asymmetries in fully reconstructed B0-->D(*)+/-pi-/+ decays in approximately 88 x 10(6) upsilon(4S)-->BBmacr; decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. From a time-dependent maximum-likelihood fit we obtain the following for the CP-violating parameters: a=-0.022+/-0.038 (stat)+/-0.020 (syst), a*=-0.068+/-0.038 (stat)+/-0.020 (syst), c(lep)=+0.025+/-0.068 (stat)+/-0.033 (syst), and c*(lep)=+0.031+/-0.070 (stat)+/-0.033 (syst). Using other measurements and theoretical assumptions we interpret the results in terms of the angles of the Cabibbo-Kobayashi-Maskawa unitarity triangle, and find |sin((2beta+gamma)|>0.69 at 68% confidence level. We exclude the hypothesis of no CP violation [sin(2beta+gamma)=0] at 83% confidence level.

  12. Measurement of Time-Dependent CP-Violating Asymmetriesand Constraints on sin(2 beta+gamma) withPartial Reconstruction of B to D*-+pi+- Decays

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, B.

    2005-04-19

    We present a measurement of the time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D*{sup {-+}}{pi}{sup {+-}}, using approximately 232 million B{bar B} events recorded by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum {pi}{sup {+-}} from the B decay and the low-momentum {pi}{sup {-+}} from the D*{sup {-+}} decay are used. We measure the parameters related to 2{beta} + {gamma} to be a{sub D*{pi}} = -0.034 {+-} 0.014 {+-} 0.009 and c{sub D*{pi}}{sup {ell}} = -0.019 {+-} 0.022 {+-} 0.013. With some theoretical assumptions, we interpret our results in terms of the lower limits |sin(2{beta} + {gamma})| > 0.62 (0.35) at 68% (90%) confidence level.

  13. Constraint-based scheduling applying constraint programming to scheduling problems

    CERN Document Server

    Baptiste, Philippe; Nuijten, Wim

    2001-01-01

    Constraint Programming is a problem-solving paradigm that establishes a clear distinction between two pivotal aspects of a problem: (1) a precise definition of the constraints that define the problem to be solved and (2) the algorithms and heuristics enabling the selection of decisions to solve the problem. It is because of these capabilities that Constraint Programming is increasingly being employed as a problem-solving tool to solve scheduling problems. Hence the development of Constraint-Based Scheduling as a field of study. The aim of this book is to provide an overview of the most widely used Constraint-Based Scheduling techniques. Following the principles of Constraint Programming, the book consists of three distinct parts: The first chapter introduces the basic principles of Constraint Programming and provides a model of the constraints that are the most often encountered in scheduling problems. Chapters 2, 3, 4, and 5 are focused on the propagation of resource constraints, which usually are responsibl...

  14. New Constraints on the Timing of Deformation in the Maberly Shear Zone, Southern Ontario, Canada from Electron Microprobe Dating of Monazite

    Science.gov (United States)

    Markley, M. J.; Dunn, S. R.; Williams, M. L.; Jercinovic, M. J.

    2016-12-01

    The Maberly Shear Zone (MSZ) is a significant terrane boundary (sensu lato) within the Central Metasedimentary Belt of the Grenville Province of Southern Ontario, Canada. The MSZ juxtaposes the granulite-facies Frontenac Terrane to the southeast against the lower-grade Sharbot Lake Terrane to the northwest. The MSZ is characterized by a mylonitic foliation that dips moderately to steeply to the southeast and a stretching lineation that rakes to the east when it occurs. Rare kinematic indicators yield an ambiguous sense of shear. Previous workers infer that shearing along the MSZ occurred soon after Shawinigan events based on mineral cooling ages and because plutons yielding U/Pb zircon ages of 1180-1160 Ma occur in both neighboring terranes. We investigated monazite from a quartzo-feldspathic biotite-bearing straight gneiss that essentially represents the type locality of the shear zone (cropping out on route 7 just west of Maberly, Ontario, at Fall River crossing). This sample is the only one of a MSZ suite to yield monazite grains, and only five grains occur; other clots of concentrated lanthanide and actinide elements are likely retrogressed monazite. Most dates from the monazite grains are in the range 1160-1120 Ma, likely the timing of significant deformation accommodated by the MSZ. This interpretation is consistent with two previously published U/Pb titanite dates for the MSZ (even though these dates were tentatively interpreted as cooling ages). One monazite domain in our study, however, yielded a date of 1038 ± 10 Ma. Microstructural observations suggest that this domain is associated with reactivation of foliation in the MSZ. Although our results appear to confirm that the development of the MSZ directly postdated the Shawinigan orogeny, they also suggest that at least some deformation occurred in the MSZ during the Ottawan Orogeny, when this region was likely high in the orogenic pile and part of the Ottawan Orogenic Lid.

  15. Soft Constraints in Interactive Behavior: The Case of Ignoring Perfect Knowledge in-the-World for Imperfect Knowledge in-the-Head

    Science.gov (United States)

    Gray, Wayne D.; Fu, Wai-Tat

    2004-01-01

    Constraints and dependencies among the elements of embodied cognition form patterns or microstrategies of interactive behavior. Hard constraints determine which microstrategies are possible. Soft constraints determine which of the possible microstrategies are most likely to be selected. When selection is non-deliberate or automatic the least…

  16. The timing of eclogite facies metamorphism and migmatization in the Orlica–Śnieżnik complex, Bohemian Massif: Constraints from a multimethod geochronological study

    Science.gov (United States)

    Brocker, M.; Klemd, R.; Cosca, M.; Brock, W.; Larionov, A.N.; Rodionov, N.

    2009-01-01

    The Orlica–Śnieżnik complex (OSC) is a key geological element of the eastern Variscides and mainly consists of amphibolite facies orthogneisses and metasedimentary rocks. Sporadic occurrences of eclogites and granulites record high-pressure (HP) to ultrahigh-pressure (UHP) metamorphic conditions. A multimethod geochronological approach (40Ar–39Ar, Rb–Sr, Sm–Nd, U–Pb) has been used to gain further insights into the polymetamorphic evolution of eclogites and associated country rocks. Special attention was given to the unresolved significance of a 370- to 360 Ma age group that was repeatedly described in previous studies. Efforts to verify the accuracy of c.370 Ma K–Ar phengite and biotite dates reported for an eclogite and associated country-rock gneiss from the location Nowa Wieś suggest that these dates are meaningless, due to contamination with extraneous Ar. Extraneous Ar is also considered to be responsible for a significantly older 40Ar–39Ar phengite date of c. 455 Ma for an eclogite from the location Wojtowka. Attempts to further substantiate the importance of 370–360 Ma zircon dates as an indicator for a melt-forming high-temperature (HT) episode did not provide evidence in support of anatectic processes at this time. Instead, SHRIMP U–Pb zircon dating of leucosomes and leucocratic veins within both orthogneisses and (U)HP granulites revealed two age populations (490–450 and 345–330 Ma respectively) that correspond to protolith ages of the magmatic precursors and late Variscan anatexis. The results of this study further underline the importance of Late Carboniferous metamorphic processes for the evolution of the OSC that comprise the waning stages of HP metamorphism and lower pressure HT overprinting with partial melting. Eclogites and their country rocks provided no chronometric evidence for an UHP and ultrahigh-temperature episode at 387–360 Ma, as recently suggested for granulites from the OSC, based on Lu–Hf garnet

  17. Constraints on timing and rates of strath terrace formation on actively uplifting anticlines in the foreland of the Chinese Tien Shan.

    Science.gov (United States)

    Bufe, A.; Burbank, D. W.; Chen, J.; Liu, L.; Li, T.; Thompson, J. A.

    2014-12-01

    The formation of strath surfaces (fluvially created, sub-horizontal erosion surfaces) requires that the rate of lateral erosion outpaces the rate of incision of a river. The change from incision to strath cutting has commonly been linked to a decrease of incision rates due to shielding of the river bed by a thick sediment cover1. Straths are abandoned when the bed cover is reduced and incision resumes. A more recent study suggests that strath terrace formation might be linked to a change between a braided and a single-thread river2. Finally, several models have explored strath formation due to inherent dynamics of meandering systems3,4. In the foreland of the Tian Shan in northwest China, weakly consolidated Pliocene sand and siltstones are being actively uplifted at rates of 1 - 3 mm/y by a series of detachment anticlines. A number of elevated, several-kilometer-wide planation surfaces bear witness to a history of multiple strath cutting events by braided streams. In contrast, modern rivers incise into the uplifting folds creating 10 - 200 m deep canyons while the up- and downstream alluvial fans remain unincised. We use GIS analysis, field mapping, and OSL dating to describe incision and beveling of the folds. Our chronologic data reveal at least 2 - 3 beveling events over the last 40 ky on the Mutule fold. We find that lateral erosion of the bedrock during beveling events occurs at rates that are more than an order of magnitude higher than average incision rates. During times of incision (which can be tens of thousands of years long), lateral erosion rates need to be considerably lower in order to explain the formation of narrow canyons. Thus, our observations of scale, rate, and intermittency of strath cutting, seem difficult to reconcile with models that explain strath formation by variations of the incision rate1 or intrinsic meandering dynamics under steady forcing3,4. The critical requirement to explain our observations appears to be repeated changes in the

  18. Trace element composition and U-Pb age of zircons from Estherville: Constraints on the timing of the metal-silicate mixing event on the mesosiderite parent body

    Science.gov (United States)

    Haba, Makiko K.; Yamaguchi, Akira; Kagi, Hiroyuki; Nagao, Keisuke; Hidaka, Hiroshi

    2017-10-01

    formed during a high-temperature reheating event, which is probably related to the metal-silicate mixing event. The weighted average 207Pb-206Pb age obtained by SIMS from both zircons is 4521 ± 26 Ma (2σ). This age is younger than that of a primary magmatic zircon from Vaca Muerta (4563 ± 15 Ma) and probably corresponds to the timing of the metal-silicate mixing event or a later impact event.

  19. Constraint theory multidimensional mathematical model management

    CERN Document Server

    Friedman, George J

    2017-01-01

    Packed with new material and research, this second edition of George Friedman’s bestselling Constraint Theory remains an invaluable reference for all engineers, mathematicians, and managers concerned with modeling. As in the first edition, this text analyzes the way Constraint Theory employs bipartite graphs and presents the process of locating the “kernel of constraint” trillions of times faster than brute-force approaches, determining model consistency and computational allowability. Unique in its abundance of topological pictures of the material, this book balances left- and right-brain perceptions to provide a thorough explanation of multidimensional mathematical models. Much of the extended material in this new edition also comes from Phan Phan’s PhD dissertation in 2011, titled “Expanding Constraint Theory to Determine Well-Posedness of Large Mathematical Models.” Praise for the first edition: "Dr. George Friedman is indisputably the father of the very powerful methods of constraint theory...

  20. Partially clairvoyant scheduling for aggregate constraints

    Directory of Open Access Journals (Sweden)

    K. Subramani

    2005-01-01

    constraints. In this paper, we extend the class of constraints for which partially clairvoyant schedules can be determined efficiently, to include aggregate constraints. Aggregate constraints form a strict superset of standard constraints and can be used to model performance metrics.

  1. Energy-Aware Synthesis of Fault-Tolerant Schedules for Real-Time Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Poulsen, Kåre Harbo; Pop, Paul; Izosimov, Viacheslav

    2007-01-01

    This paper presents a design optimisation tool for distributed embedded real-time systems that 1) decides mapping, fault-tolerance policy and generates a fault-tolerant schedule, 2) is targeted for hard real-time, 3) has hard reliability goal, 4) generates static schedule for processes and messag......, 5) provides fault-tolerance for k transient/soft faults, 6) optimises for minimal energy consumption, while considering impact of lowering voltages on the probability of faults, 7) uses constraint logic programming (CLP) based implementation....

  2. "Work smart, wear your hard hat"

    CERN Multimedia

    2003-01-01

    Falling objects and collisions are frequent occurrences in work sites and hazardous areas. Hard hats can help prevent many types of accident and can even save lives. Just imagine an 800 g spanner falling from a 13 m high scaffold onto the head of someone standing below - a nightmare scenario! The impact to the head is equivalent to that of a 5 kg weight falling from 2 metres. That is just what happened to Gerd Fetchenhauer when he was working on the UA1 experiment. Fortunately, he was wearing a hard hat at the time. "That hat saved my life," he explains. "It punched a hole right through the hat and I was a bit dazed for a couple of hours but otherwise I was OK." Since that day, Gerd Fetchenhauer, now working on CMS, is never seen on a work site without his hard hat on. Work sites have proliferated at CERN with the construction of the LHC and its detectors, and the wearing of hard hats is compulsory (not to mention life-saving). In the underground caverns and experiment halls, where gantry cranes and other h...

  3. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  4. Hard X-ray bremsstrahlung production in solar flares by high-energy proton beams

    Science.gov (United States)

    Emslie, A. G.; Brown, J. C.

    1985-01-01

    The possibility that solar hard X-ray bremsstrahlung is produced by acceleration of stationary electrons by fast-moving protons, rather than vice versa, as commonly assumed, was investigated. It was found that a beam of protons which involves 1836 times fewer particles, each having an energy 1836 times greater than that of the electrons in the equivalent electron beam model, has exactly the same bremsstrahlung yield for a given target, i.e., the mechanism has an energetic efficiency equal to that of conventional bremsstrahlung models. Allowance for the different degrees of target ionization appropriate to the two models (for conventional flare geometries) makes the proton beam model more efficient than the electron beam model, by a factor of order three. The model places less stringent constraints than a conventional electron beam model on the flare energy release mechanism. It is also consistent with observed X-ray burst spectra, intensities, and directivities. The altitude distribution of hard X-rays predicted by the model agrees with observations only if nonvertical injection of the protons is assumed. The model is inconsistent with gamma-ray data in terms of conventional modeling.

  5. Zircon U-Pb ages and Hf isotope compositions of the Mayuan migmatite complex, NW Fujian Province, Southeast China: Constraints on the timing and nature of a regional tectonothermal event associated with the Caledonian orogeny

    Science.gov (United States)

    Liu, Rui; Zhou, Hanwen; Zhang, Li; Zhong, Zengqiu; Zeng, Wen; Xiang, Hua; Jin, Song; Lu, Xinqian; Li, Chunzhong

    2010-10-01

    U-Pb ages, trace elements, and Hf isotope compositions of zircons from the Mayuan migmatite complex in NW Fujian province have been determined to provide constraints on the source and genesis of anatexis and tectonothermal evolution related to the Caledonian orogeny in South China. The migmatites investigated consist of various amounts of mesosome, leucosome, and melansome. Zircons extracted from mesosome, leucosome, and granite samples are characterized by oscillatory overgrowths enclosing inherited cores or occur as newly grown grains. The ages of the inherited zircons from the leucosome and granite samples are consistent with those of adjacent basement paragneiss in the study area, suggesting that both leucosome and granite were generated by partial melting of the latter. A comparison of Hf isotopes between the newly-formed zircons and inherited cores indicates that the former resulted from the breakdown of preexisting inherited zircons and/or less Hf-rich minerals other than zircons at the source. One mesosome sample contains typical metamorphic zircons that yielded a weighted mean 206Pb/ 238U age of 453 ± 3 Ma. They show enrichments in heavy REEs (Lu N/La N up to 22,709), indicating their growth prior to garnet crystallization. The other mesosome sample, in contrast, contains both newly-formed metamorphic rims and grains that gave a weighted mean 206Pb/ 238U age of 442 ± 8 Ma. They are characterized by relatively low Th/U ratios, depletions in heavy REEs (Lu N/La N = 117-396), and low 176Lu/ 177Hf ratios, suggesting their growth synchronous with garnet crystallization. The U-Pb ages of the mesosome samples are interpreted as recording the time of early (ca. 453 Ma) to peak (442 Ma) stages of a regional metamorphic event. Two leucosome and two granite samples yield consistent U-Pb ages of 438 ± 5 Ma to 442 ± 4 Ma, which provide constraints on the timing of subsequent anatexis and magmatism. The geochronological data reported here reveal a consecutive

  6. The NCL natural constraint language

    CERN Document Server

    Zhou, Jianyang

    2012-01-01

    This book presents the Natural Constraint Language (NCL) language, a description language in conventional mathematical logic for modeling and solving constraint satisfaction problems. It uses illustrations and tutorials to detail NCL and its applications.

  7. Hiding quiet solutions in random constraint satisfaction problems

    Energy Technology Data Exchange (ETDEWEB)

    Zdeborova, Lenka [Los Alamos National Laboratory; Krzakala, Florent [Los Alamos National Laboratory

    2008-01-01

    We study constraint satisfaction problems on the so-called planted random ensemble. We show that for a certain class of problems, e.g., graph coloring, many of the properties of the usual random ensemble are quantitatively identical in the planted random ensemble. We study the structural phase transitions and the easy-hard-easy pattern in the average computational complexity. We also discuss the finite temperature phase diagram, finding a close connection with the liquid-glass-solid phenomenology.

  8. Partially clairvoyant scheduling for aggregate constraints

    OpenAIRE

    Subramani, K.

    2005-01-01

    The problem of partially clairvoyant scheduling is concerned with checking whether an ordered set of jobs, having nonconstant execution times and subject to a collection of imposed constraints, has a partially clairvoyant schedule. Variability of execution times of jobs and nontrivial relationships constraining their executions, are typical features of real-time systems. A partially clairvoyant scheduler parameterizes the schedule, in that the start time of a job in a sequence can depend u...

  9. The perceived constraints, motivation, and physical activity levels of ...

    African Journals Online (AJOL)

    The purpose of this research was threefold; Are Korean youth physically active to promote health during leisure time? What constraints to physical active do youth experience during leisure time? Are there relationships among constraints, motivation, and physical activity level? Of 1 280 youth randomly selected by a ...

  10. Development of procedure and analysis of hard rock drilling

    OpenAIRE

    Omdal, Kjetil

    2015-01-01

    Master's thesis in Petroleum engineering Over the last few years the petroleum industry have experienced a drastically increase in drilling costs. At the same time the oil prize has been highly unstable resulting in an increased focus on reducing drilling costs. The aim of this thesis is to look for cost reducing measures when drilling in hard rock formations offshore. Drilling in hard formations is both challenging and time consuming as a consequence of Low Rate of Penetration (ROP) ...

  11. Making decisions in real-time and hard times

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.M. [Univ. of North Carolina, Chapel Hill, NC (United States)

    1994-12-31

    These conditions create the need for an ethical discourse which goes beyond the traditional. ARe there ways to preserve personal integrity? Are there approaches for companies to understand and articulate workable value systems, which serve both company and employee needs? Is it possible to negotiate between conflicting loyalties to self and to work? Can principles such as Fairness, Caring, and Justice have a meaningful role in today`s workplace?

  12. Study Smart Not Hard

    Directory of Open Access Journals (Sweden)

    Imane KAMSA

    2018-01-01

    Full Text Available Learners’ concentration is an essential factor for learning and acquisition. The duration of concentration varies from one individual to another. Some learners have a long duration of concentration; whereas, others have a short one. Leaving the learner in front of a screen for a random duration is a strategy that does not optimize online learning. In this perspective, we have implemented an approach based on three intelligent agents customizing and adapting the learning time according to the learner's concentration time. The first agent is called "Detector Agent" (DA.The task of this agent is to measure the learner's concentration time and to detect the factors that may influence it. The second agent is named "Scheduler Agent" (SA. Its function is to cut the time of a session in proportion to the concentration time measured by DA and to program relaxing breaks in order to regenerate the degree of concentration. And finally, the third agent is called "Rectifier Agent" (RA. The latter is responsible for rectifying the factors that negatively influence the concentration of the learners. These agents continuously communicate between each other in order to ensure an efficient treatment. The experienced results show that the approach contributes effectively in the acquisition and the performance of learners. Success rates have risen sharply and the learners express a growing satisfaction.

  13. Hard-phase engineering in hard/soft nanocomposite magnets

    Science.gov (United States)

    Poudyal, Narayan; Rong, Chuanbing; Vuong Nguyen, Van; Liu, J. Ping

    2014-03-01

    Bulk SmCo/Fe(Co) based hard/soft nanocomposite magnets with different hard phases (1:5, 2:17, 2:7 and 1:3 types) were fabricated by high-energy ball-milling followed by a warm compaction process. Microstructural studies revealed a homogeneous distribution of bcc-Fe(Co) phase in the matrix of hard magnetic Sm-Co phase with grain size ⩽20 nm after severe plastic deformation and compaction. The small grain size leads to effective inter-phase exchange coupling as shown by the single-phase-like demagnetization behavior with enhanced remanence and energy product. Among the different hard phases investigated, it was found that the Sm2Co7-based nanocomposites can incorporate a higher soft phase content, and thus a larger reduction in rare-earth content compared with the 2:17, 1:5 and 1:3 phase-based nanocomposite with similar properties. (BH)max up to 17.6 MGOe was obtained for isotropic Sm2Co7/FeCo nanocomposite magnets with 40 wt% of the soft phase which is about 300% higher than the single-phase counterpart prepared under the same conditions. The results show that hard-phase engineering in nanocomposite magnets is an alternative approach to fabrication of high-strength nanocomposite magnets with reduced rare-earth content.

  14. Constraints influencing sports wheelchair propulsion performance and injury risk

    Science.gov (United States)

    2013-01-01

    The Paralympic Games are the pinnacle of sport for many athletes with a disability. A potential issue for many wheelchair athletes is how to train hard to maximise performance while also reducing the risk of injuries, particularly to the shoulder due to the accumulation of stress placed on this joint during activities of daily living, training and competition. The overall purpose of this narrative review was to use the constraints-led approach of dynamical systems theory to examine how various constraints acting upon the wheelchair-user interface may alter hand rim wheelchair performance during sporting activities, and to a lesser extent, their injury risk. As we found no studies involving Paralympic athletes that have directly utilised the dynamical systems approach to interpret their data, we have used this approach to select some potential constraints and discussed how they may alter wheelchair performance and/or injury risk. Organism constraints examined included player classifications, wheelchair setup, training and intrinsic injury risk factors. Task constraints examined the influence of velocity and types of locomotion (court sports vs racing) in wheelchair propulsion, while environmental constraints focused on forces that tend to oppose motion such as friction and surface inclination. Finally, the ecological validity of the research studies assessing wheelchair propulsion was critiqued prior to recommendations for practice and future research being given. PMID:23557065

  15. An Extensive Evaluation of Portfolio Approaches for Constraint Satisfaction Problems

    Directory of Open Access Journals (Sweden)

    Roberto Amadini

    2016-06-01

    Full Text Available In the context of Constraint Programming, a portfolio approach exploits the complementary strengths of a portfolio of different constraint solvers. The goal is to predict and run the best solver(s of the portfolio for solving a new, unseen problem. In this work we reproduce, simulate, and evaluate the performance of different portfolio approaches on extensive benchmarks of Constraint Satisfaction Problems. Empirical results clearly show the benefits of portfolio solvers in terms of both solved instances and solving time.

  16. Liquidity Constraints in Production Based Asset Pricing Models

    OpenAIRE

    Brock, William A.; Blake LeBaron

    1989-01-01

    This paper explores the time series implications of introducing credit constraints into a production based asset pricing model. Simulations are performed choosing parameter values which generate reasonable values for aggregate fluctuations. These results show that mean reversion in simulated returns series, measured by variance ration tests, is enhanced with the introduction of binding credit constraints. Without these constraints there is very little evidence of mean reversion. This is consi...

  17. A constructive heuristic for time-dependent multi-depot vehicle routing problem with time-windows and heterogeneous fleet

    Directory of Open Access Journals (Sweden)

    Behrouz Afshar-Nadjafi

    2017-01-01

    Full Text Available In this paper, we consider the time-dependent multi-depot vehicle routing problem. The objective is to minimize the total heterogeneous fleet cost assuming that the travel time between locations depends on the departure time. Also, hard time window constraints for the customers and limitation on maximum number of the vehicles in depots must be satisfied. The problem is formulated as a mixed integer programming model. A constructive heuristic procedure is proposed for the problem. Also, the efficiency of the proposed algorithm is evaluated on 180 test problems. The obtained computational results indicate that the procedure is capable to obtain a satisfying solution.

  18. Chandra and Suzaku Follow-up Observations of Hard X-ray Selected AGN in the UDIS

    Science.gov (United States)

    Virani, Shanil N.; Urry, C. M.; Treister, E.; Schawinski, K.; Maccarone, T. J.; Beckmann, V.; Coppi, P.

    2010-01-01

    We carried out a 3 Megasecond Ultra-Deep INTEGRAL Survey (UDIS) to define a faint hard X-ray-selected AGN sample, unbiased by even the heaviest obscuration. The space density of AGN that are Compton-thick (NH>1024 cm-2) remains unknown even though it has been suggested they could nearly equal the space density of less obscured supermassive black holes. In the Ultra-Deep INTEGRAL Survey, one of the deepest surveys of the hard X-ray sky ever done, we detect 15 AGN some of which are detected in the hard X-rays for the first time. In order to measure the obscuration and the high-energy reflection component for these sources, we obtained follow-up observations with Chandra and Suzaku. Here we present X-ray spectra for all 15 AGN, including the inferred distribution of absorbing column densities. Measurement and modeling of the X-ray background provides at best an integral and degenerate constraint on AGN populations, which only weakly constrains the most obscured objects as they make only a minor contribution to the background. Direct detection of heavily obscured objects by surveys like UDIS is thus the only way to obtain a true census of their population.

  19. Maximizing Entropy of Pickard Random Fields for 2x2 Binary Constraints

    DEFF Research Database (Denmark)

    Søgaard, Jacob; Forchhammer, Søren

    2014-01-01

    This paper considers the problem of maximizing the entropy of two-dimensional (2D) Pickard Random Fields (PRF) subject to constraints. We consider binary Pickard Random Fields, which provides a 2D causal finite context model and use it to define stationary probabilities for 2x2 squares, thus...... allowing us to calculate the entropy of the field. All possible binary 2x2 constraints are considered and all constraints are categorized into groups according to their properties. For constraints which can be modeled by a PRF approach and with positive entropy, we characterize and provide statistics...... of the maximum PRF entropy. As examples, we consider the well known hard square constraint along with a few other constraints....

  20. Solving constraint satisfaction problems with networks of spiking neurons

    Directory of Open Access Journals (Sweden)

    Zeno eJonke

    2016-03-01

    Full Text Available Network of neurons in the brain apply – unlike processors in our current generation ofcomputer hardware – an event-based processing strategy, where short pulses (spikes areemitted sparsely by neurons to signal the occurrence of an event at a particular point intime. Such spike-based computations promise to be substantially more power-efficient thantraditional clocked processing schemes. However it turned out to be surprisingly difficult todesign networks of spiking neurons that can solve difficult computational problems on the levelof single spikes (rather than rates of spikes. We present here a new method for designingnetworks of spiking neurons via an energy function. Furthermore we show how the energyfunction of a network of stochastically firing neurons can be shaped in a quite transparentmanner by composing the networks of simple stereotypical network motifs. We show that thisdesign approach enables networks of spiking neurons to produce approximate solutions todifficult (NP-hard constraint satisfaction problems from the domains of planning/optimizationand verification/logical inference. The resulting networks employ noise as a computationalresource. Nevertheless the timing of spikes (rather than just spike rates plays an essential rolein their computations. Furthermore, networks of spiking neurons carry out for the Traveling Salesman Problem a more efficient stochastic search for good solutions compared with stochastic artificial neural networks (Boltzmann machines and Gibbs sampling.

  1. Studying Hardness Meter Spring Strength to Understand Hardness Distribution on Body Surfaces.

    Science.gov (United States)

    Arima, Yoshitaka

    2017-10-01

    For developing a hardness multipoint measurement system for understanding hardness distribution on biological body surfaces, we investigated the spring strength of the contact portion main axis of a biological tissue hardness meter (product name: PEK). We measured the hardness of three-layered sheets of six types of gel sheets (90 mm × 60 mm × 6 mm) constituting the acupuncture practice pads, with PEK measurements of 1.96 N, 2.94 N, 3.92 N, 4.90 N, 5.88 N, 6.86 N, 7.84 N, 8.82 N, and 9.81 N of the main axis spring strength. We obtained measurements 10 times for the gel sheets and simultaneously measured the load using a digital scale. We measured the hardness distribution of induration embedded and breast cancer palpation models, with a main axis with 1.96 N, 4.90 N, and 9.81 N spring strengths, to create a two-dimensional Contour Fill Chart. Using 4.90 N spring strength, we could obtain measurement loads of ≤3.0 N, and the mean hardness was 5.14 mm. This was close to the median of the total measurement range 0.0-10.0 mm, making the measurement range the largest for this spring strength. We could image the induration of the induration-embedded model regardless of the spring strength. Overall, 4.90 N spring strength was best suited for imaging cancer in the breast cancer palpation model. Copyright © 2017. Published by Elsevier B.V.

  2. On Kalman Filtering With Nonlinear Equality Constraints

    Science.gov (United States)

    2007-06-01

    1)). The filter is updated with the observation to give the unconstrained estimate x̂ ( kjk ). The constraint is applied to give the final estimate x̂... kjk ). II. PROBLEM STATEMENT We seek the minimum-mean squared error estimate of the state vector of the nonlinear discrete time system where is the

  3. PACKING CIRCLES WITHIN CIRCULAR CONTAINERS: A NEW HEURISTIC ALGORITHM FOR THE BALANCE CONSTRAINTS CASE

    Directory of Open Access Journals (Sweden)

    Washington Alves de Oliveira

    Full Text Available ABSTRACT In this work we propose a heuristic algorithm for the layout optimization for disks installed in a rotating circular container. This is a unequal circle packing problem with additional balance constraints. It proved to be an NP-hard problem, which justifies heuristics methods for its resolution in larger instances. The main feature of our heuristic is based on the selection of the next circle to be placed inside the container according to the position of the system's center of mass. Our approach has been tested on a series of instances up to 55 circles and compared with the literature. Computational results show good performance in terms of solution quality and computational time for the proposed algorithm.

  4. Diffusion Processes Satisfying a Conservation Law Constraint

    Directory of Open Access Journals (Sweden)

    J. Bakosi

    2014-01-01

    Full Text Available We investigate coupled stochastic differential equations governing N nonnegative continuous random variables that satisfy a conservation principle. In various fields a conservation law requires a set of fluctuating variables to be nonnegative and (if appropriately normalized sum to one. As a result, any stochastic differential equation model to be realizable must not produce events outside of the allowed sample space. We develop a set of constraints on the drift and diffusion terms of such stochastic models to ensure that both the nonnegativity and the unit-sum conservation law constraints are satisfied as the variables evolve in time. We investigate the consequences of the developed constraints on the Fokker-Planck equation, the associated system of stochastic differential equations, and the evolution equations of the first four moments of the probability density function. We show that random variables, satisfying a conservation law constraint, represented by stochastic diffusion processes, must have diffusion terms that are coupled and nonlinear. The set of constraints developed enables the development of statistical representations of fluctuating variables satisfying a conservation law. We exemplify the results with the bivariate beta process and the multivariate Wright-Fisher, Dirichlet, and Lochner’s generalized Dirichlet processes.

  5. Chemical hardness and density functional theory

    Indian Academy of Sciences (India)

    Keywords. Hardness; softness; hard & soft acids bases (HSAB); principle of maximum hardness (PMH) density functional theory (DFT). Abstract. The concept of chemical hardness is reviewed from a personal point of view. Author Affiliations. Ralph G Pearson1. Chemistry Department, University of California, Santa Barbara, ...

  6. Hardness variability in commercial and hardened technologies

    Energy Technology Data Exchange (ETDEWEB)

    Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.

    1994-03-01

    Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is ``built-in`` through statistical process control (SPC) of technology parameters relevant to the radiation response, test structure to integrated circuit (IC) correlations, and techniques for extrapolating laboratory test results to varying radiation scenarios. At the same time, there has been renewed interest in the use of commercial technology -- with its enhanced performance, reduced cost, and higher reliability -- in military and space systems. In this paper, we initially demonstrate the application of QML techniques to assure and control the radiation response of hardened technologies. Through several examples, we demonstrate intra-die, wafer-to-wafer, and lot-to-lot variations in a hardened technology. We observe 10 to 30% variations in key technology parameters that result from variability in geometry, process, and design layout. Radiation-induced degradation is seen to mirror preirradiation characteristics. We then evaluate commercial technologies and report considerably higher variability in radiation hardness, i.e., variations by a factor of two to five. This variability is shown to arise from a lack of control of technology parameters relevant to the radiation response, which a commercial manufacturer has no interest in controlling in a normal process flow.

  7. Constraints and Ambiguity

    DEFF Research Database (Denmark)

    Dove, Graham; Biskjær, Michael Mose; Lundqvist, Caroline Emilie

    2017-01-01

    Developing creative abilities is an important part of 21st century skills, and yet remains challenging. In this paper we describe a study investigating small-scale creative strategies that groups of Scandinavian high school students use when collaboratively building LEGO models. We recorded thirty...... groups of students building three models each. We studied groups building with traditional plastic bricks and also using a digital environment. The building tasks students undertake, and our subsequent analysis, are informed by the role constraints and ambiguity play in creative processes. Based...... on the insights we gained, we present three strategies for designing tools and environments that support students as they develop creative skills. These strategies relate to: tools and materials, mutual learning, and reflection...

  8. Relative constraints and evolution

    Science.gov (United States)

    Ochoa, Juan G. Diaz

    2014-03-01

    Several mathematical models of evolving systems assume that changes in the micro-states are constrained to the search of an optimal value in a local or global objective function. However, the concept of evolution requires a continuous change in the environment and species, making difficult the definition of absolute optimal values in objective functions. In this paper, we define constraints that are not absolute but relative to local micro-states, introducing a rupture in the invariance of the phase space of the system. This conceptual basis is useful to define alternative mathematical models for biological (or in general complex) evolving systems. We illustrate this concept with a modified Ising model, which can be useful to understand and model problems like the somatic evolution of cancer.

  9. Microindentation Hardness of Protein Crystals under Controlled Relative Humidity

    Directory of Open Access Journals (Sweden)

    Takeharu Kishi

    2017-11-01

    Full Text Available Vickers microindentation hardness of protein crystals was investigated on the (110 habit plane of tetragonal hen egg-white lysozyme crystals containing intracrystalline water at controlled relative humidity. The time evolution of the hardness of the crystals exposed to air with different humidities exhibits three stages such as the incubation, transition, and saturation stages. The hardness in the incubation stage keeps a constant value of 16 MPa, which is independent of the humidity. The incubation hardness can correspond to the intrinsic one in the wet condition. The increase of the hardness in the transition and saturation stages is well fitted with the single exponential curve, and is correlated with the reduction of water content in the crystal by the evaporation. The saturated maximum hardness also strongly depends on the water content equilibrated with the humidity. The slip traces corresponding to the (11 ̅0[110] slip system around the indentation marks are observed in not only incubation but also saturation stages. It is suggested that the plastic deformation in protein crystals by the indentation can be attributed to dislocation multiplication and motion inducing the slip. The indentation hardness in protein crystals is discussed in light of dislocation mechanism with Peierls stress and intracrystalline water.

  10. The effects of perceived leisure constraints among Korean university students

    Science.gov (United States)

    Sae-Sook Oh; Sei-Yi Oh; Linda L. Caldwell

    2002-01-01

    This study is based on Crawford, Jackson, and Godbey's model of leisure constraints (1991), and examines the relationships between the influences of perceived constraints, frequency of participation, and health status in the context of leisure-time outdoor activities. The study was based on a sample of 234 Korean university students. This study provides further...

  11. Internal and external stabilisation of linear systems with constraints

    NARCIS (Netherlands)

    Saberi, Ali; Stoorvogel, Antonie Arij; Sannuti, Peddapullaiah

    2012-01-01

    Linear systems with constraints on inputs and states are ubiquitous. Control of such systems has been a long-time challenge to control engineers and will continue to remain so. Indeed, the challenge of constraints is intense and dauntingly formidable and familiar. This book focuses on the very

  12. Path following mobile robot in the presence of velocity constraints

    DEFF Research Database (Denmark)

    Bak, Martin; Poulsen, Niels Kjølstad; Ravn, Ole

    2001-01-01

    This paper focuses on path following algorithms for mobile robots with velocity constraints on the wheels. The path considered consists of straight lines intersected with given angles. We present a fast real-time receding horizon controller which anticipates the intersections and smoothly controls...... the robot through the turnings while fulfilling the velocity constraints....

  13. An Introduction to 'Creativity Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Biskjaer, Michael Mose

    Constraints play a vital role as both restrainers and enablers in innovation processes by governing what the creative agent/s can and cannot do, and what the output can and cannot be. Notions of constraints are common in creativity research, but current contributions are highly dispersed due to n...... and sub-concepts, including ‘late’, ‘self-imposed’, and ‘continua of creativity constraints’, to inform future cross-disciplinary work on creativity constraints....

  14. Solving Sudoku with Constraint Programming

    Science.gov (United States)

    Crawford, Broderick; Castro, Carlos; Monfroy, Eric

    Constraint Programming (CP) is a powerful paradigm for modeling and solving Complex Combinatorial Problems (generally issued from Decision Making). In this work, we model the known Sudoku puzzle as a Constraint Satisfaction Problems and solve it with CP comparing the performance of different Variable and Value Selection Heuristics in its Enumeration phase. We encourage this kind of benchmark problem because it may suggest new techniques in constraint modeling and solving of complex systems, or aid the understanding of its main advantages and limits.

  15. Constraint-Based Categorial Grammar

    CERN Document Server

    Bouma, G; Bouma, Gosse; Noord, Gertjan van

    1994-01-01

    We propose a generalization of Categorial Grammar in which lexical categories are defined by means of recursive constraints. In particular, the introduction of relational constraints allows one to capture the effects of (recursive) lexical rules in a computationally attractive manner. We illustrate the linguistic merits of the new approach by showing how it accounts for the syntax of Dutch cross-serial dependencies and the position and scope of adjuncts in such constructions. Delayed evaluation is used to process grammars containing recursive constraints.

  16. Minimal Flavor Constraints for Technicolor

    DEFF Research Database (Denmark)

    Sakuma, Hidenori; Sannino, Francesco

    2010-01-01

    We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and mas......We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self...

  17. Deepening Contractions and Collateral Constraints

    DEFF Research Database (Denmark)

    Jensen, Henrik; Ravn, Søren Hove; Santoro, Emiliano

    and occasionally non-binding credit constraints. Easier credit access increases the likelihood that constraints become slack in the face of expansionary shocks, while contractionary shocks are further amplified due to tighter constraints. As a result, busts gradually become deeper than booms. Based...... on the differential impact that occasionally non-binding constraints exert on the shape of expansions and contractions, we are also able to reconcile a more negatively skewed business cycle with a moderation in its volatility. Finally, our model can account for an intrinsic feature of economic downturns preceded...

  18. Stress in hard metal films

    NARCIS (Netherlands)

    Janssen, G.C.A.M.; Kamminga, J.D.

    2004-01-01

    In the absence of thermal stress, tensile stress in hard metal films is caused by grain boundary shrinkage and compressive stress is caused by ion peening. It is shown that the two contributions are additive. Moreover tensile stress generated at the grain boundaries does not relax by ion

  19. Inclusive Hard Diffraction at HERA

    CERN Document Server

    Proskuryakov, Alexander

    2010-01-01

    Recent data from the H1 and ZEUS experiments on hard inclusive diffraction are discussed. Results of QCD analyses of the diffractive deep-inelastic scattering processes are reported. Predictions based on the extracted parton densities are compared to diffractive dijet measurements.

  20. Modifier constraint in alkali borophosphate glasses using topological constraint theory

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zeng, Huidan, E-mail: hdzeng@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Jiang, Qi [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhao, Donghui [Unifrax Corporation, Niagara Falls, NY 14305 (United States); Chen, Guorong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Wang, Zhaofeng; Sun, Luyi [Department of Chemical & Biomolecular Engineering and Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (United States); Chen, Jianding [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2016-12-01

    In recent years, composition-dependent properties of glasses have been successfully predicted using the topological constraint theory. The constraints of the glass network are derived from two main parts: network formers and network modifiers. The constraints of the network formers can be calculated on the basis of the topological structure of the glass. However, the latter cannot be accurately calculated in this way, because of the existing of ionic bonds. In this paper, the constraints of the modifier ions in phosphate glasses were thoroughly investigated using the topological constraint theory. The results show that the constraints of the modifier ions are gradually increased with the addition of alkali oxides. Furthermore, an improved topological constraint theory for borophosphate glasses is proposed by taking the composition-dependent constraints of the network modifiers into consideration. The proposed theory is subsequently evaluated by analyzing the composition dependence of the glass transition temperature in alkali borophosphate glasses. This method is supposed to be extended to other similar glass systems containing alkali ions.

  1. Neoplasms of the hard palate.

    Science.gov (United States)

    Aydil, Utku; Kızıl, Yusuf; Bakkal, Faruk Kadri; Köybaşıoğlu, Ahmet; Uslu, Sabri

    2014-03-01

    Although the most common neoplastic lesion of the oral cavity is squamous cell carcinoma (SCC), primary neoplastic lesions of the hard palate have not been systematically reviewed to date. The aim of this study was to determine the histopathologic composition and characteristics of neoplasms of the hard palate. A retrospective analysis of 66 patients with a primary neoplasm of the hard palate managed at the authors' institution from 1985 through 2012 was performed. Demographic features, malignancy rate, histopathologic characteristics and distribution, TNM staging results, metastasis patterns, and management strategies were investigated. The sample was composed of 66 patients (mean age, 45.0 yr; 57.6% men). Neoplasms were benign in 57.6% of cases and malignant in 42.4%. Epithelial neoplasms and mesenchymal neoplasms were encountered in 52 patients (78.8%) and 14 patients (21.2%), respectively. Minor salivary gland tumors (MSGTs) were the most common histopathologic group (60.6%), followed by benign mesenchymal tumors (15.2%), SCCs (12.1%), malignant melanomas (6.1%), lymphomas (3.0%), and sarcomas (3.0%). Although 75.0% of malignant epithelial neoplasms were at an advanced stage, there were no pN+ SCC or malignant MSGT cases at presentation. The most common neoplasms of the hard palate were MSGTs. SCCs were relatively rare in this series. Although three-fourths of neoplasms were at an advanced stage, neck metastasis was not a characteristic of malignant epithelial neoplasms located in the hard palate. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  2. Relation of hardness with FWHM and residual stress of GCr15 steel after shot peening

    Science.gov (United States)

    Fu, Peng; Chu, Ruiqing; Xu, Zhijun; Ding, Guanjun; Jiang, Chuanhai

    2018-02-01

    The variations of XRD full width at half maximum (FWHM), residual stress and hardness for the surface of GCr15 steel after triple shot peening (TSP) as a function of annealing time and temperature are studied. The results show that with the increase of annealing temperature and time, hardness and FWHM increase gradually while compressive residual stress (CRS) decreases gradually. CRS and micro- structure work together on the hardness values, and the micro-structure is the most important factor for hardness. According to establishing the quantitive relationship of hardness with FWHM and CRS, the value of hardness can be calculated; a new type of noncontact and nondestructive hardness testing can be realized by XRD method.

  3. An overview on polynomial approximation of NP-hard problems

    Directory of Open Access Journals (Sweden)

    Paschos Vangelis Th.

    2009-01-01

    Full Text Available The fact that polynomial time algorithm is very unlikely to be devised for an optimal solving of the NP-hard problems strongly motivates both the researchers and the practitioners to try to solve such problems heuristically, by making a trade-off between computational time and solution's quality. In other words, heuristic computation consists of trying to find not the best solution but one solution which is 'close to' the optimal one in reasonable time. Among the classes of heuristic methods for NP-hard problems, the polynomial approximation algorithms aim at solving a given NP-hard problem in poly-nomial time by computing feasible solutions that are, under some predefined criterion, as near to the optimal ones as possible. The polynomial approximation theory deals with the study of such algorithms. This survey first presents and analyzes time approximation algorithms for some classical examples of NP-hard problems. Secondly, it shows how classical notions and tools of complexity theory, such as polynomial reductions, can be matched with polynomial approximation in order to devise structural results for NP-hard optimization problems. Finally, it presents a quick description of what is commonly called inapproximability results. Such results provide limits on the approximability of the problems tackled.

  4. Constraint Programming for Context Comprehension

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2014-01-01

    A close similarity is demonstrated between context comprehension, such as discourse analysis, and constraint programming. The constraint store takes the role of a growing knowledge base learned throughout the discourse, and a suitable con- straint solver does the job of incorporating new pieces...

  5. Constraints in vector meson photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Kloet, W. M.; Tabakin, F

    2000-01-31

    Constraints are discussed for spin observables extracted from photoproduction of vector mesons. These constraints originate from positivity of the spin density matrix and should be part of any future analysis of experimental data. Spin observables need to be defined in the photon-nucleon c.m. frame.

  6. Constraints in Vector Meson Photoproduction

    Science.gov (United States)

    Kloet, W. M.; Tabakin, F.

    2000-01-01

    Constraints are discussed for spin observables extracted from photoproduction of vector mesons. These constraints originate from positivity of the spin density matrix and should be part of any future analysis of experimental data. Spin observables need to be defined in the photon-nucleon c.m. frame.

  7. Thermodynamic Constraints Improve Metabolic Networks.

    Science.gov (United States)

    Krumholz, Elias W; Libourel, Igor G L

    2017-08-08

    In pursuit of establishing a realistic metabolic phenotypic space, the reversibility of reactions is thermodynamically constrained in modern metabolic networks. The reversibility constraints follow from heuristic thermodynamic poise approximations that take anticipated cellular metabolite concentration ranges into account. Because constraints reduce the feasible space, draft metabolic network reconstructions may need more extensive reconciliation, and a larger number of genes may become essential. Notwithstanding ubiquitous application, the effect of reversibility constraints on the predictive capabilities of metabolic networks has not been investigated in detail. Instead, work has focused on the implementation and validation of the thermodynamic poise calculation itself. With the advance of fast linear programming-based network reconciliation, the effects of reversibility constraints on network reconciliation and gene essentiality predictions have become feasible and are the subject of this study. Networks with thermodynamically informed reversibility constraints outperformed gene essentiality predictions compared to networks that were constrained with randomly shuffled constraints. Unconstrained networks predicted gene essentiality as accurately as thermodynamically constrained networks, but predicted substantially fewer essential genes. Networks that were reconciled with sequence similarity data and strongly enforced reversibility constraints outperformed all other networks. We conclude that metabolic network analysis confirmed the validity of the thermodynamic constraints, and that thermodynamic poise information is actionable during network reconciliation. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  8. On Constraints in Assembly Planning

    Energy Technology Data Exchange (ETDEWEB)

    Calton, T.L.; Jones, R.E.; Wilson, R.H.

    1998-12-17

    Constraints on assembly plans vary depending on product, assembly facility, assembly volume, and many other factors. Assembly costs and other measures to optimize vary just as widely. To be effective, computer-aided assembly planning systems must allow users to express the plan selection criteria that appIy to their products and production environments. We begin this article by surveying the types of user criteria, both constraints and quality measures, that have been accepted by assembly planning systems to date. The survey is organized along several dimensions, including strategic vs. tactical criteria; manufacturing requirements VS. requirements of the automated planning process itself and the information needed to assess compliance with each criterion. The latter strongly influences the efficiency of planning. We then focus on constraints. We describe a framework to support a wide variety of user constraints for intuitive and efficient assembly planning. Our framework expresses all constraints on a sequencing level, specifying orders and conditions on part mating operations in a number of ways. Constraints are implemented as simple procedures that either accept or reject assembly operations proposed by the planner. For efficiency, some constraints are supplemented with special-purpose modifications to the planner's algorithms. Fast replanning enables an interactive plan-view-constrain-replan cycle that aids in constraint discovery and documentation. We describe an implementation of the framework in a computer-aided assembly planning system and experiments applying the system to a number of complex assemblies, including one with 472 parts.

  9. Fixed Costs and Hours Constraints

    Science.gov (United States)

    Johnson, William R.

    2011-01-01

    Hours constraints are typically identified by worker responses to questions asking whether they would prefer a job with more hours and more pay or fewer hours and less pay. Because jobs with different hours but the same rate of pay may be infeasible when there are fixed costs of employment or mandatory overtime premia, the constraint in those…

  10. Weighted Constraints in Fuzzy Optimization

    NARCIS (Netherlands)

    U. Kaymak (Uzay); J.M. Sousa

    2001-01-01

    textabstractMany practical optimization problems are characterized by some flexibility in the problem constraints, where this flexibility can be exploited for additional trade-off between improving the objective function and satisfying the constraints. Especially in decision making, this type of

  11. Market segmentation using perceived constraints

    Science.gov (United States)

    Jinhee Jun; Gerard Kyle; Andrew Mowen

    2008-01-01

    We examined the practical utility of segmenting potential visitors to Cleveland Metroparks using their constraint profiles. Our analysis identified three segments based on their scores on the dimensions of constraints: Other priorities--visitors who scored the highest on 'other priorities' dimension; Highly Constrained--visitors who scored relatively high on...

  12. Integrity Constraints in Trust Management

    NARCIS (Netherlands)

    Etalle, Sandro; Winsborough, William H.

    We introduce the use, monitoring, and enforcement of integrity constraints in trust managementstyle authorization systems. We consider what portions of the policy state must be monitored to detect violations of integrity constraints. Then we address the fact that not all participants in a trust

  13. Nanomechanics of hard films on compliant substrates.

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, Earl David, Jr. (Sandia National Laboratories, Albuquerque, NM); Emerson, John Allen (Sandia National Laboratories, Albuquerque, NM); Bahr, David F. (Washington State University, Pullman, WA); Moody, Neville Reid; Zhou, Xiao Wang; Hales, Lucas (University of Minnesota, Minneapolis, MN); Adams, David Price (Sandia National Laboratories, Albuquerque, NM); Yeager,John (Washington State University, Pullman, WA); Nyugen, Thao D. (Johns Hopkins University, Baltimore, MD); Corona, Edmundo (Sandia National Laboratories, Albuquerque, NM); Kennedy, Marian S. (Clemson University, Clemson, SC); Cordill, Megan J. (Erich Schmid Institute, Leoben, Austria)

    2009-09-01

    Development of flexible thin film systems for biomedical, homeland security and environmental sensing applications has increased dramatically in recent years [1,2,3,4]. These systems typically combine traditional semiconductor technology with new flexible substrates, allowing for both the high electron mobility of semiconductors and the flexibility of polymers. The devices have the ability to be easily integrated into components and show promise for advanced design concepts, ranging from innovative microelectronics to MEMS and NEMS devices. These devices often contain layers of thin polymer, ceramic and metallic films where differing properties can lead to large residual stresses [5]. As long as the films remain substrate-bonded, they may deform far beyond their freestanding counterpart. Once debonded, substrate constraint disappears leading to film failure where compressive stresses can lead to wrinkling, delamination, and buckling [6,7,8] while tensile stresses can lead to film fracture and decohesion [9,10,11]. In all cases, performance depends on film adhesion. Experimentally it is difficult to measure adhesion. It is often studied using tape [12], pull off [13,14,15], and peel tests [16,17]. More recent techniques for measuring adhesion include scratch testing [18,19,20,21], four point bending [22,23,24], indentation [25,26,27], spontaneous blisters [28,29] and stressed overlayers [7,26,30,31,32,33]. Nevertheless, sample design and test techniques must be tailored for each system. There is a large body of elastic thin film fracture and elastic contact mechanics solutions for elastic films on rigid substrates in the published literature [5,7,34,35,36]. More recent work has extended these solutions to films on compliant substrates and show that increasing compliance markedly changes fracture energies compared with rigid elastic solution results [37,38]. However, the introduction of inelastic substrate response significantly complicates the problem [10,39,40]. As

  14. Conservation constraints on random matrices

    CERN Document Server

    Ma Wen Jong; Hsieh, J

    2003-01-01

    We study the random matrices constrained by the summation rules that are present in the Hessian of the potential energy surface in the instantaneous normal mode calculations, as a result of momentum conservation. In this paper, we analyse the properties related to such conservation constraints in two classes of real symmetric matrices: one with purely row-wise summation rules and the other with the constraints on the blocks of each matrix, which underscores partially the spatial dimension. We show explicitly that the constraints are removable by separating the degrees of freedom of the zero-eigenvalue modes. The non-spectral degrees of freedom under the constraints can be realized in terms of the ordinary constraint-free orthogonal symmetry but with the rank deducted by the block dimension. We propose that the ensemble of real symmetric matrices with full randomness, constrained by the summation rules, is equivalent to the Gaussian orthogonal ensemble (GOE) with lowered rank. Independent of the joint probabil...

  15. Efficient Searching with Linear Constraints

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars Allan; Erickson, Jeff

    2000-01-01

    We show how to preprocess a set S of points in d into an external memory data structure that efficiently supports linear-constraint queries. Each query is in the form of a linear constraint xd a0+∑d−1i=1 aixi; the data structure must report all the points of S that satisfy the constraint...... space and answers linear-constraint queries using an optimal number of I/Os in the worst case. For d=3, we present a near-linear-size data structure that answers queries using an optimal number of I/Os on the average. We present linear-size data structures that can answer d-dimensional linear-constraint...

  16. Towards Practical Whitebox Cryptography: Optimizing Efficiency and Space Hardness

    DEFF Research Database (Denmark)

    Bogdanov, Andrey; Isobe, Takanori; Tischhauser, Elmar Wolfgang

    2016-01-01

    security for the resistance against key extraction and decomposition, SPNbox attains speed-ups of up to 6.5 times in the black box and up to 18 times in the white box on Intel Skylake and ARMv8 CPUs, compared to SPACE. The designs allow for constant-time implementations in the blackbox setting and meet...... the practical requirements to whitebox cryptography in real-world applications such as DRM or mobile payments. Moreover, we formalize resistance towards decomposition in form of weak and strong space hardness at various security levels. We obtain bounds on space hardness in all those adversarial models...

  17. Exact sampling hardness of Ising spin models

    Science.gov (United States)

    Fefferman, B.; Foss-Feig, M.; Gorshkov, A. V.

    2017-09-01

    We study the complexity of classically sampling from the output distribution of an Ising spin model, which can be implemented naturally in a variety of atomic, molecular, and optical systems. In particular, we construct a specific example of an Ising Hamiltonian that, after time evolution starting from a trivial initial state, produces a particular output configuration with probability very nearly proportional to the square of the permanent of a matrix with arbitrary integer entries. In a similar spirit to boson sampling, the ability to sample classically from the probability distribution induced by time evolution under this Hamiltonian would imply unlikely complexity theoretic consequences, suggesting that the dynamics of such a spin model cannot be efficiently simulated with a classical computer. Physical Ising spin systems capable of achieving problem-size instances (i.e., qubit numbers) large enough so that classical sampling of the output distribution is classically difficult in practice may be achievable in the near future. Unlike boson sampling, our current results only imply hardness of exact classical sampling, leaving open the important question of whether a much stronger approximate-sampling hardness result holds in this context. The latter is most likely necessary to enable a convincing experimental demonstration of quantum supremacy. As referenced in a recent paper [A. Bouland, L. Mancinska, and X. Zhang, in Proceedings of the 31st Conference on Computational Complexity (CCC 2016), Leibniz International Proceedings in Informatics (Schloss Dagstuhl-Leibniz-Zentrum für Informatik, Dagstuhl, 2016)], our result completes the sampling hardness classification of two-qubit commuting Hamiltonians.

  18. CMS results on hard diffraction

    CERN Document Server

    INSPIRE-00107098

    2013-01-01

    In these proceedings we present CMS results on hard diffraction. Diffractive dijet production in pp collisions at $\\sqrt{s}$=7 TeV is discussed. The cross section for dijet production is presented as a function of $\\tilde{\\xi}$, representing the fractional momentum loss of the scattered proton in single-diffractive events. The observation of W and Z boson production in events with a large pseudo-rapidity gap is also presented.

  19. Playing Moderately Hard to Get

    Directory of Open Access Journals (Sweden)

    Stephen Reysen

    2013-12-01

    Full Text Available In two studies, we examined the effect of different degrees of attraction reciprocation on ratings of attraction toward a potential romantic partner. Undergraduate college student participants imagined a potential romantic partner who reciprocated a low (reciprocating attraction one day a week, moderate (reciprocating attraction three days a week, high (reciprocating attraction five days a week, or unspecified degree of attraction (no mention of reciprocation. Participants then rated their degree of attraction toward the potential partner. The results of Study 1 provided only partial support for Brehm’s emotion intensity theory. However, after revising the high reciprocation condition vignette in Study 2, supporting Brehm’s emotion intensity theory, results show that a potential partners’ display of reciprocation of attraction acted as a deterrent to participants’ intensity of experienced attraction to the potential partner. The results support the notion that playing moderately hard to get elicits more intense feelings of attraction from potential suitors than playing too easy or too hard to get. Discussion of previous research examining playing hard to get is also re-examined through an emotion intensity theory theoretical lens.

  20. Outdoor weathering of facial prosthetic elastomers differing in Durometer hardness.

    Science.gov (United States)

    Willett, Emily S; Beatty, Mark W

    2015-03-01

    Facial prosthetic elastomers with wide ranges in hardness are available, yet material weatherability is unknown. The purpose of this study was to assess color, Durometer hardness, and tensile property changes after 3000 hours of outdoor weathering. Unpigmented elastomers with Durometer hardness 5, 30, 50, 70, and A-2186 were polymerized into dumbbells (ASTM D412) and disks, 34 mm in diameter by 6 mm thick. Materials were subjected to outdoor or time passage environments for 3000 hours. CIELab color (n=5), Durometer hardness (n=5), and tensile mechanical properties (n=10) were measured at 0 and 3000 hours, and group differences were assessed by material and weathering condition (ANOVA/Tukey, α=.05). Except for A-2186, the mean Durometer changes for all materials were 1 unit or less, with no significant differences observed between time passage and weathered groups (P≥.05). Three-thousand-hour tensile mechanical property results demonstrated nonsignificant differences between time passage and weathered materials but significantly changed properties from immediately tested materials (Phardness 5 and 30 and A-2186. With a few exceptions, outdoor weathering produced relatively small changes in color, Durometer hardness, or tensile properties compared with time passage. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. Free energy calculations using flexible-constrained, hard-constrained and non-constrained molecular dynamics simulations.

    Science.gov (United States)

    Christen, Markus; Christ, Clara D; van Gunsteren, Wilfred F

    2007-07-16

    A comparison of different treatments of bond-stretching interactions in molecular dynamics simulation is presented. Relative free energies from simulations using rigid bonds maintained with the SHAKE algorithm, using partially rigid bonds maintained with a recently introduced flexible constraints algorithm, and using fully flexible bonds are compared in a multi-configurational thermodynamic integration calculation of changing liquid water into liquid methanol. The formula for the free energy change due to a changing flexible constraint in a flexible constraint simulation is derived. To allow for a more direct comparison between these three methods, three different pairs of models for water and methanol were used: a flexible model (simulated without constraints and with flexible constraints), a rigid model (simulated with standard hard constraints), and an alternative flexible model (simulated with flexible constraints and standard hard constraints) in which the ideal or constrained bond lengths correspond to the average bond lengths obtained from a short simulation of the unconstrained flexible model. The particular treatment of the bonds induces differences of up to 2 % in the liquid densities, whereas (excess) free energy differences of up to 5.7 (4.3) kJ mol(-1) are observed. These values are smaller than the differences observed between the three different pairs of methanol/water models: up to 5 % in density and up to 8.5 kJ mol(-1) in (excess) free energy.

  2. Physical and numerical constraints in source modeling for finite difference simulation of room acoustics.

    Science.gov (United States)

    Sheaffer, Jonathan; van Walstijn, Maarten; Fazenda, Bruno

    2014-01-01

    In finite difference time domain simulation of room acoustics, source functions are subject to various constraints. These depend on the way sources are injected into the grid and on the chosen parameters of the numerical scheme being used. This paper addresses the issue of selecting and designing sources for finite difference simulation, by first reviewing associated aims and constraints, and evaluating existing source models against these criteria. The process of exciting a model is generalized by introducing a system of three cascaded filters, respectively, characterizing the driving pulse, the source mechanics, and the injection of the resulting source function into the grid. It is shown that hard, soft, and transparent sources can be seen as special cases within this unified approach. Starting from the mechanics of a small pulsating sphere, a parametric source model is formulated by specifying suitable filters. This physically constrained source model is numerically consistent, does not scatter incoming waves, and is free from zero- and low-frequency artifacts. Simulation results are employed for comparison with existing source formulations in terms of meeting the spectral and temporal requirements on the outward propagating wave.

  3. Investment Timing When External Financing Is Costly

    DEFF Research Database (Denmark)

    Hirth, Stefan; Uhrig-Homburg, Marliese

    2010-01-01

    This paper analyzes the investment timing of firms facing two dimensions of financing constraints: Liquidity constraints and capital market frictions inducing financing costs. We show that liquidity constraints are not sufficient to explain voluntary investment delay. However, when additionally...

  4. Vocabulary Constraint on Texts

    Directory of Open Access Journals (Sweden)

    C. Sutarsyah

    2008-01-01

    Full Text Available This case study was carried out in the English Education Department of State University of Malang. The aim of the study was to identify and describe the vocabulary in the reading text and to seek if the text is useful for reading skill development. A descriptive qualitative design was applied to obtain the data. For this purpose, some available computer programs were used to find the description of vocabulary in the texts. It was found that the 20 texts containing 7,945 words are dominated by low frequency words which account for 16.97% of the words in the texts. The high frequency words occurring in the texts were dominated by function words. In the case of word levels, it was found that the texts have very limited number of words from GSL (General Service List of English Words (West, 1953. The proportion of the first 1,000 words of GSL only accounts for 44.6%. The data also show that the texts contain too large proportion of words which are not in the three levels (the first 2,000 and UWL. These words account for 26.44% of the running words in the texts.  It is believed that the constraints are due to the selection of the texts which are made of a series of short-unrelated texts. This kind of text is subject to the accumulation of low frequency words especially those of content words and limited of words from GSL. It could also defeat the development of students' reading skills and vocabulary enrichment.

  5. Generalized arc consistency for global cardinality constraint

    Energy Technology Data Exchange (ETDEWEB)

    Regin, J.C. [ILOG S.A., Gentilly (France)

    1996-12-31

    A global cardinality constraint (gcc) is specified in terms of a set of variables X = (x{sub 1},..., x{sub p}) which take their values in a subset of V = (v{sub 1},...,v{sub d}). It constrains the number of times a value v{sub i} {epsilon} V is assigned to a variable in X to be in an interval [l{sub i}, c{sub i}]. Cardinality constraints have proved very useful in many real-life problems, such as scheduling, timetabling, or resource allocation. A gcc is more general than a constraint of difference, which requires each interval to be. In this paper, we present an efficient way of implementing generalized arc consistency for a gcc. The algorithm we propose is based on a new theorem of flow theory. Its space complexity is O({vert_bar}X{vert_bar} {times} {vert_bar}V{vert_bar}) and its time complexity is O({vert_bar}X{vert_bar}{sup 2} {times} {vert_bar}V{vert_bar}). We also show how this algorithm can efficiently be combined with other filtering techniques.

  6. Researches regarding the optimization of thermal treatment depending on hardness for maraging 300 steel

    Directory of Open Access Journals (Sweden)

    A. Nioaţă

    2013-04-01

    Full Text Available The paper presents researches regarding the optimization of aging thermal treatment and solution heat treatment for MARAGING 300, in order to get a certain hardness value. Experimental data processing resulted from the study of MARAGING 300 steel hardness dependence on the temperature and aging maintenance time and solution heat treatment was made using Statistica program. Results have allowed to determine some mathematic patterns for determining heating temperature, maintenance time respectively in order to get a certain steel hardness.

  7. A Selfish Constraint Satisfaction Genetic Algorithms for Planning a Long-Distance Transportation Network

    Science.gov (United States)

    Onoyama, Takashi; Maekawa, Takuya; Kubota, Sen; Tsuruta, Setuso; Komoda, Norihisa

    To build a cooperative logistics network covering multiple enterprises, a planning method that can build a long-distance transportation network is required. Many strict constraints are imposed on this type of problem. To solve these strict-constraint problems, a selfish constraint satisfaction genetic algorithm (GA) is proposed. In this GA, each gene of an individual satisfies only its constraint selfishly, disregarding the constraints of other genes in the same individuals. Moreover, a constraint pre-checking method is also applied to improve the GA convergence speed. The experimental result shows the proposed method can obtain an accurate solution in a practical response time.

  8. Why Are Drugs So Hard to Quit?

    Medline Plus

    Full Text Available ... Quitting drugs is hard because addiction is a brain disease. Your brain is like a control tower that sends out ... and choices. Addiction changes the signals in your brain and makes it hard to feel OK without ...

  9. Hardness of Potable Water in Southwestern Skane

    OpenAIRE

    Kos, Z.

    1982-01-01

    This paper is concerned with water hardness in the municipal water supply systems. After a general overview of the health aspects of water hardness, this issue is discussed in the specific context of Southwestern Skane, Sweden.

  10. The Department Chair during Fiscal Constraints: Visionary Shop Foreman.

    Science.gov (United States)

    Horton, Susan R.

    1994-01-01

    Considers the role of the English department head in a time of fiscal constraint and retrenchment. Describes the special responsibilities necessitated by lean financial circumstances. Discusses department/administration relations and the public relations aspect of chairing a department. (HB)

  11. Order-to-chaos transition in the hardness of random Boolean satisfiability problems

    Science.gov (United States)

    Varga, Melinda; Sumi, Róbert; Toroczkai, Zoltán; Ercsey-Ravasz, Mária

    2016-05-01

    Transient chaos is a ubiquitous phenomenon characterizing the dynamics of phase-space trajectories evolving towards a steady-state attractor in physical systems as diverse as fluids, chemical reactions, and condensed matter systems. Here we show that transient chaos also appears in the dynamics of certain efficient algorithms searching for solutions of constraint satisfaction problems that include scheduling, circuit design, routing, database problems, and even Sudoku. In particular, we present a study of the emergence of hardness in Boolean satisfiability (k -SAT), a canonical class of constraint satisfaction problems, by using an analog deterministic algorithm based on a system of ordinary differential equations. Problem hardness is defined through the escape rate κ , an invariant measure of transient chaos of the dynamical system corresponding to the analog algorithm, and it expresses the rate at which the trajectory approaches a solution. We show that for a given density of constraints and fixed number of Boolean variables N , the hardness of formulas in random k -SAT ensembles has a wide variation, approximable by a lognormal distribution. We also show that when increasing the density of constraints α , hardness appears through a second-order phase transition at αχ in the random 3-SAT ensemble where dynamical trajectories become transiently chaotic. A similar behavior is found in 4-SAT as well, however, such a transition does not occur for 2-SAT. This behavior also implies a novel type of transient chaos in which the escape rate has an exponential-algebraic dependence on the critical parameter κ ˜NB |α - αχ|1-γ with 0 <γ <1 . We demonstrate that the transition is generated by the appearance of metastable basins in the solution space as the density of constraints α is increased.

  12. Analysis of optical flow constraints.

    Science.gov (United States)

    Del Bimbo, A; Nesi, P; Sanz, J C

    1995-01-01

    Different constraint equations have been proposed in the literature for the derivation of optical flow. Despite of the large number of papers dealing with computational techniques to estimate optical flow, only a few authors have investigated conditions under which these constraints exactly model the velocity field, that is, the perspective projection on the image plane of the true 3-D velocity. These conditions are analyzed under different hypotheses, and the departures of the constraint equations in modeling the velocity field are derived for different motion conditions. Experiments are also presented giving measures of these departures and of the induced errors in the estimation of the velocity field.

  13. Concurrent Constraint Machine Improvisation: Models and Implementation

    OpenAIRE

    Toro, Mauricio

    2015-01-01

    Machine improvisation creates music either by explicit coding of rules or by applying machine learning methods. We deal with the latter case. An improvisation system capable of real-time must execute two process concurrently: one to apply machine learning methods to musical sequences in order to capture prominent musical features, and one to produce musical sequences stylistically consistent with the learned material. As an example, the Concurrent Constraint Factor Oracle Model for Music Impr...

  14. Detecting Cliques Using Degree and Connectivity Constraints

    OpenAIRE

    Abhay Avinash Bhamaikar; Pralhad Ramchandra Rao

    2012-01-01

    In graph mining determining clique is np complete problem. This paper introduces pruning strategies, by which linear time algorithm for detecting clique is obtained. Clique determination is widely applicable in social network analysis. In social network analysis cliques signifies that each person in the network knows every other person in the group. Here pruning is done using edge connectivity and degree constraints. Initially the graph (g) is checked for a bridge, if it is detected, then g...

  15. Embedded System Synthesis under Memory Constraints

    DEFF Research Database (Denmark)

    Madsen, Jan; Bjørn-Jørgensen, Peter

    1999-01-01

    This paper presents a genetic algorithm to solve the system synthesis problem of mapping a time constrained single-rate system specification onto a given heterogeneous architecture which may contain irregular interconnection structures. The synthesis is performed under memory constraints, that is......, the algorithm takes into account the memory size of processors and the size of interface buffers of communication links, and in particular the complicated interplay of these. The presented algorithm is implemented as part of the LY-COS cosynthesis system....

  16. Contact Allergy To Hard Contact Lens

    Directory of Open Access Journals (Sweden)

    J S Pasricha

    1985-01-01

    Full Text Available Three patients developed recurrent irritation, redness and watery discharge from their eyes after using hard contact lens. Patch tests were positive with the material of the hard contact lens and negative with teepol, sodium lauryl sulphate and material of the soft contact lens. All the three patients became alright after they stopped,using hard contact lens.

  17. 7 CFR 201.30 - Hard seed.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.30 Section 201.30 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Vegetable Seeds § 201.30 Hard seed. The label shall show the percentage of hard seed, if...

  18. 7 CFR 201.21 - Hard seed.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seed. 201.21 Section 201.21 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.21 Hard seed. The label shall show the percentage of hard seed...

  19. Systematic hardness measurements on single crystals and ...

    Indian Academy of Sciences (India)

    Vickers and knoop hardness measurements were carried out on CsBr and CsI single crystals. Polycrystalline blanks of CsCl, CsBr and CsI were prepared by melting and characterized by X-ray diffraction. Vickers hardness measurements were carried out on these blanks. The hardness values were correlated with the lattice ...

  20. Systematic hardness studies on lithium niobate crystals

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 23; Issue 2. Systematic hardness studies on lithium niobate crystals ... In view of discrepancies in the available information on the hardness of lithium niobate, a systematic study of the hardness has been carried out. Measurements have been made on two pure lithium ...

  1. 7 CFR 201.57 - Hard seeds.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hard seeds. 201.57 Section 201.57 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Germination Tests in the Administration of the Act § 201.57 Hard seeds. Seeds which remain hard at...

  2. Systematic hardness studies on lithium niobate crystals

    Indian Academy of Sciences (India)

    Unknown

    1975) made Knoop hardness ... mentioned that Knoop and Vickers hardness values generally agree to within 5% (Mott 1956). Brown et al ... In the present communication, we report a detailed study of the load-dependence of hardness on two ...

  3. Unique sodium phosphosilicate glasses designed through extended topological constraint theory.

    Science.gov (United States)

    Zeng, Huidan; Jiang, Qi; Liu, Zhao; Li, Xiang; Ren, Jing; Chen, Guorong; Liu, Fude; Peng, Shou

    2014-05-15

    Sodium phosphosilicate glasses exhibit unique properties with mixed network formers, and have various potential applications. However, proper understanding on the network structures and property-oriented methodology based on compositional changes are lacking. In this study, we have developed an extended topological constraint theory and applied it successfully to analyze the composition dependence of glass transition temperature (Tg) and hardness of sodium phosphosilicate glasses. It was found that the hardness and Tg of glasses do not always increase with the content of SiO2, and there exist maximum hardness and Tg at a certain content of SiO2. In particular, a unique glass (20Na2O-17SiO2-63P2O5) exhibits a low glass transition temperature (589 K) but still has relatively high hardness (4.42 GPa) mainly due to the high fraction of highly coordinated network former Si((6)). Because of its convenient forming and manufacturing, such kind of phosphosilicate glasses has a lot of valuable applications in optical fibers, optical amplifiers, biomaterials, and fuel cells. Also, such methodology can be applied to other types of phosphosilicate glasses with similar structures.

  4. Natural Constraints to Species Diversification.

    Directory of Open Access Journals (Sweden)

    Eric Lewitus

    2016-08-01

    Full Text Available Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the

  5. Topology Optimization with Stress Constraints

    NARCIS (Netherlands)

    Verbart, A.

    2015-01-01

    This thesis contains contributions to the development of topology optimization techniques capable of handling stress constraints. The research that led to these contributions was motivated by the need for topology optimization techniques more suitable for industrial applications. Currently, topology

  6. An Introduction to 'Creativity Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Biskjær, Michael Mose

    2013-01-01

    Constraints play a vital role as both restrainers and enablers in innovation processes by governing what the creative agent/s can and cannot do, and what the output can and cannot be. Notions of constraints are common in creativity research, but current contributions are highly dispersed due...... to no overall conceptual framing or shared terminology. This lack of unity hinders overt opportunities for cross-disciplinary interchange. We argue that an improved understanding of constraints in creativity holds a promising potential for advancements in creativity research across domains and disciplines. Here......, we give an overview of the growing, but incohesive body of research into creativity and constraints, which leads us to introduce ‘creativity constraints’ as a unifying concept to help bridge these disjoint contributions to facilitate crossdisciplinary interchange. Finally, we suggest key topics...

  7. Estimating Hardness from the USDC Tool-Bit Temperature Rise

    Science.gov (United States)

    Bar-Cohen, Yoseph; Sherrit, Stewart

    2008-01-01

    A method of real-time quantification of the hardness of a rock or similar material involves measurement of the temperature, as a function of time, of the tool bit of an ultrasonic/sonic drill corer (USDC) that is being used to drill into the material. The method is based on the idea that, other things being about equal, the rate of rise of temperature and the maximum temperature reached during drilling increase with the hardness of the drilled material. In this method, the temperature is measured by means of a thermocouple embedded in the USDC tool bit near the drilling tip. The hardness of the drilled material can then be determined through correlation of the temperature-rise-versus-time data with time-dependent temperature rises determined in finite-element simulations of, and/or experiments on, drilling at various known rates of advance or known power levels through materials of known hardness. The figure presents an example of empirical temperature-versus-time data for a particular 3.6-mm USDC bit, driven at an average power somewhat below 40 W, drilling through materials of various hardness levels. The temperature readings from within a USDC tool bit can also be used for purposes other than estimating the hardness of the drilled material. For example, they can be especially useful as feedback to control the driving power to prevent thermal damage to the drilled material, the drill bit, or both. In the case of drilling through ice, the temperature readings could be used as a guide to maintaining sufficient drive power to prevent jamming of the drill by preventing refreezing of melted ice in contact with the drill.

  8. Radiation Hardness Assurance (RHA) Guideline

    Science.gov (United States)

    Campola, Michael J.

    2016-01-01

    Radiation Hardness Assurance (RHA) consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the mission space environment. The subset of interests for NEPP and the REAG, are EEE parts. It is important to register that all of these undertakings are in a feedback loop and require constant iteration and updating throughout the mission life. More detail can be found in the reference materials on applicable test data for usage on parts.

  9. Hard Identity and Soft Identity

    Directory of Open Access Journals (Sweden)

    Hassan Rachik

    2006-04-01

    Full Text Available Often collective identities are classified depending on their contents and rarely depending on their forms. Differentiation between soft identity and hard identity is applied to diverse collective identities: religious, political, national, tribal ones, etc. This classification is made following the principal dimensions of collective identities: type of classification (univocal and exclusive or relative and contextual, the absence or presence of conflictsof loyalty, selective or totalitarian, objective or subjective conception, among others. The different characteristics analysed contribute to outlining an increasingly frequent type of identity: the authoritarian identity.

  10. Can Leverage Constraints Help Investors?

    OpenAIRE

    Heimer, Rawley

    2014-01-01

    This paper provides causal evidence that leverage constraints can reduce the underperformance of individual investors. In accordance with Dodd-Frank, the CFTC was given regulatory authority over the retail market for foreign exchange and capped the maximum permissible leverage available to U.S. traders. By comparing U.S. traders on the same brokerages with their unregulated European counterparts, I show that the leverage constraint reduces average per-trade losses even after adjusting for ris...

  11. Risk Sharing under Incentive Constraints.

    OpenAIRE

    Wagner, W.B.

    2002-01-01

    In addressing the matter, this thesis covers issues such as the welfare gains from international risk sharing, the impact of international risk sharing on national economic policies and production efficiency, the welfare effects of international risk sharing in the presence of tax competition, and risk sharing among entrepreneurs that face financing constraints. The thesis outlines the implications of incentive constraints for the efficiency of the actual extent and pattern of risk sharing am...

  12. Enhancing Formal Specification and Verification of Temporal Constraints in Business Processes

    OpenAIRE

    Cheikhrouhou, Saoussen; Kallel, Slim; Guermouche, Nawal; Jmaiel, Mohamed

    2014-01-01

    International audience; Formal specification and verification support of time-related constraints constitute fundamental challenges for any Business Process Management (BPM) system. Reluctantly, the literature on the subject of formal specification and verification of advanced temporal constraints such as absolute temporal constraints associated with relative temporal constraints is scarce. In this paper, we propose a novel approach enabling the formal specification and verification of advanc...

  13. Hard X-ray Emission along the Z Track in GX 17+ 2

    Indian Academy of Sciences (India)

    -ray Timing Experiment (HEXTE) on board Rossi X-Ray Timing Explorer for Z source GX 17+2, we investigate the evolution of its PCA spectra and HEXTE spectra along a `Z' track on its hardness-intensity diagram. A hard X-ray tail is detected ...

  14. Architecture in Mission Integration, Choreographing Constraints

    Science.gov (United States)

    Jones, Rod

    2000-01-01

    In any building project the Architect's role and skill is to balance the client's requirements with the available technology, a site and budget. Time, place and resources set the boundaries and constraints of the project. If these boundaries are correctly understood and respected by the Architect they can be choreographed into producing a facility that abides by those constraints and successfully meets the clients needs. The design and assembly of large scale space facilities whether in orbit around or on the surface of a planet require and employs these same skills. In this case the site is the International Space Station (ISS) which operates at a nominal rendezvous altitude of 220 nautical miles. With supplies to support a 7 day mission the Shuttle nominally has a cargo capacity of 35,000 pounds to that altitude. Through the Mission Integration process the Launch Package Management Team choreographs the constraints of ascent performance, hardware design, cargo, rendezvous, mission duration and assembly time in order to meet the mission objective.

  15. Color fringe projection profilometry using geometric constraints

    Science.gov (United States)

    Cheng, Teng; Du, Qingyu; Jiang, Yaxi

    2017-09-01

    A recently proposed phase unwrapping method using geometric constraints performs well without requiring additional camera, more patterns or global search. The major limitation of this technique is the confined measurement depth range (MDR) within 2π in phase domain. To enlarge the MDR, this paper proposes using color fringes for three-dimensional (3D) shape measurement. Each six fringe periods encoded with six different colors are treated as one group. The local order within one group can be identified with reference to the color distribution. Then the phase wrapped period-by-period is converted into the phase wrapped group-by-group. The geometric constraints of the fringe projection system are used to determine the group order. Such that the MDR is extended from 2π to 12π by six times. Experiment results demonstrate the success of the proposed method to measure two isolated objects with large MDR.

  16. Financial Constraints and Exports: Evidence from Portuguese Manufacturing Firms

    Directory of Open Access Journals (Sweden)

    Armando Silva

    2011-12-01

    Full Text Available This paper analyses the links between financial constraints and firm export behaviour, at the firm level, by using data on Portuguese manufacturing enterprises. Previous empirical literature has not yet reached a consensus on these subjects and there is a great heterogeneity in measuring financial constraints. In line with a very recent trend, we approximate credit constraints by using a financial score built on eight variables. In order to assess the effects of exports on the financial status of firms we apply, for the first time to these types of studies, a propensity score matching with difference in differences. We find that new exporters show significant improvements in their financial situation.

  17. Hardness map of human meta tarsals and phalanges of toes.

    Science.gov (United States)

    Manarvi, Irfan

    2016-08-01

    Predicting location of fracture in human bones has been a keen area of research for the past few decades. A variety of tests for hardness, deformation and strain field measurement have been conducted in the past; but considered insufficient due to various limitations. Researchers therefore have proposed further studies due to inaccuracies in measurement methods, testing machines and experimental errors. Advancement and availability of hardware, measuring instrumentation and testing machines can now provide remedies to these limitations. Human foot is a critical part of body exposed to various forces throughout its life. A number of products are developed for using over it for protection and care. Which many times do not provide sufficient protection and may itself become a source of stress due to non-consideration of the delicacy of bones in the feet. A continuous strain or overloading on feet may occur resulting to discomfort and even fracture. Not knowing how the hardness is spread all over the Meta tarsals and phalanges is one of major contributory factor for unsatisfactory design of foot protection products. This paper provides a complete hardness distribution map developed by experimental testing of all the Meta tarsals and Phalanges of toes for a typical human foot. The bones were taken from two left feet of a 40 and 42 year old male cadaver. These were dehydrated prior to measurements of hardness using Leeb hardness testing method. Hardness was measured around the circumference of a bone as well as along its length. Hardness values can be related to tensile strength of the bones to predict possible values of stress that could be borne by these bones. Results may also be used for design and developing various accessories for human feet health care and comfort.

  18. Powered Descent Guidance with General Thrust-Pointing Constraints

    Science.gov (United States)

    Carson, John M., III; Acikmese, Behcet; Blackmore, Lars

    2013-01-01

    The Powered Descent Guidance (PDG) algorithm and software for generating Mars pinpoint or precision landing guidance profiles has been enhanced to incorporate thrust-pointing constraints. Pointing constraints would typically be needed for onboard sensor and navigation systems that have specific field-of-view requirements to generate valid ground proximity and terrain-relative state measurements. The original PDG algorithm was designed to enforce both control and state constraints, including maximum and minimum thrust bounds, avoidance of the ground or descent within a glide slope cone, and maximum speed limits. The thrust-bound and thrust-pointing constraints within PDG are non-convex, which in general requires nonlinear optimization methods to generate solutions. The short duration of Mars powered descent requires guaranteed PDG convergence to a solution within a finite time; however, nonlinear optimization methods have no guarantees of convergence to the global optimal or convergence within finite computation time. A lossless convexification developed for the original PDG algorithm relaxed the non-convex thrust bound constraints. This relaxation was theoretically proven to provide valid and optimal solutions for the original, non-convex problem within a convex framework. As with the thrust bound constraint, a relaxation of the thrust-pointing constraint also provides a lossless convexification that ensures the enhanced relaxed PDG algorithm remains convex and retains validity for the original nonconvex problem. The enhanced PDG algorithm provides guidance profiles for pinpoint and precision landing that minimize fuel usage, minimize landing error to the target, and ensure satisfaction of all position and control constraints, including thrust bounds and now thrust-pointing constraints.

  19. Removal of hard COD, nitrogenous compounds and phenols from a ...

    African Journals Online (AJOL)

    2015-07-04

    Jul 4, 2015 ... ABSTRACT. The objective of this study was to identify the factors affecting the suspended and fixed biomass in the removal of hard. COD, nitrogenous compounds and phenols from a coal gasification wastewater (CGWW) stream using a hybrid fixed- film bioreactor (H-FFBR) process under real-time plant ...

  20. Removal of hard COD, nitrogenous compounds and phenols from a ...

    African Journals Online (AJOL)

    The objective of this study was to identify the factors affecting the suspended and fixed biomass in the removal of hard COD, nitrogenous compounds and phenols from a coal gasification wastewater (CGWW) stream using a hybrid fixed-film bioreactor (H-FFBR) process under real-time plant operational conditions and ...