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Sample records for mercier criterion

  1. Mercier criterion modified by kinetic effects

    SciTech Connect

    Rosenbluth, M.N.; Porcelli, F.

    1996-12-31

    The ideal MHD Mercier criterion for the stability of localized interchange modes is easily violated by modest pressure gradients in the central region of a Tokamak plasma where the magnetic winding index q drops below unity. However, kinetic effects can substantially modify this criterion, allowing for stable peaked pressure profiles. In this paper, we discuss the modifications to the Mercier criterion brought about by the fusion alpha particles and by the thermal trapped ions in the collisionless Kruskal-Oberman limit.

  2. Unified theory of Mercier-ballooning and Alfven eigenmodes in positive-shear tokamaks with large-orbit energetic ions

    SciTech Connect

    Mikhailovskii, A.B.; Kovalishen, E.A.; Tsypin, V.S.; Galvao, R.M.O.

    2005-04-15

    A unified theory of the Mercier-ballooning and the compensating-electron Alfven eigenmodes (CEAEs) in positive-shear tokamaks with large-orbit energetic ions is developed. It is shown that the cross-field drift effect of electrons compensating the electric charge of energetic ions (the compensating-electron effect) leads to rotation of the Mercier-ballooning modes. If the Mercier stability criterion is satisfied, the ballooning modes rotate in the direction of compensating-electron frequency, while in violation of this stability criterion the unstable modes rotate against this frequency. The compensating-electron effect also results in decreasing the growth rate of ballooning modes, though their instability condition is unchanged. The Mercier and ballooning effects influence both rotation and decay rate of the CEAEs, the ballooning effect being smaller than the Mercier effect. As a result, rotation and damping of CEAEs increases/decreases in the case of magnetic well/hill.

  3. EdF`s Mercier on the biggest maintenance program in the world

    SciTech Connect

    Mercier, E.F.

    1993-08-01

    This article presents an interview with Jean-Pierre Mercier, present vice president of operations and maintenance engineering at Electricite de France (EdF). The maintenance budget for EdF is in the range of 1.5 to 1.7 billion US dollars per year. Mercier discusses the changing direction of the EdF maintenance program, with increasing emphasis on human performance, safety culture, and professionalism at the power station sites and among the many outside contractors.

  4. Generalized energy failure criterion.

    PubMed

    Qu, R T; Zhang, Z J; Zhang, P; Liu, Z Q; Zhang, Z F

    2016-01-01

    Discovering a generalized criterion that can predict the mechanical failure of various different structural materials is one of ultimate goals for scientists in both material and mechanics communities. Since the first study on the failure criterion of materials by Galileo, about three centuries have passed. Now we eventually find the "generalized energy criterion", as presented here, which appears to be one universal law for various different kinds of materials. The validity of the energy criterion for quantitatively predicting the failure is experimentally confirmed using a metallic glass. The generalized energy criterion reveals the competition and interaction between shear and cleavage, the two fundamental inherent failure mechanisms, and thus provides new physical insights into the failure prediction of materials and structural components. PMID:26996781

  5. Generalized energy failure criterion

    PubMed Central

    Qu, R. T.; Zhang, Z. J.; Zhang, P.; Liu, Z. Q.; Zhang, Z. F.

    2016-01-01

    Discovering a generalized criterion that can predict the mechanical failure of various different structural materials is one of ultimate goals for scientists in both material and mechanics communities. Since the first study on the failure criterion of materials by Galileo, about three centuries have passed. Now we eventually find the “generalized energy criterion”, as presented here, which appears to be one universal law for various different kinds of materials. The validity of the energy criterion for quantitatively predicting the failure is experimentally confirmed using a metallic glass. The generalized energy criterion reveals the competition and interaction between shear and cleavage, the two fundamental inherent failure mechanisms, and thus provides new physical insights into the failure prediction of materials and structural components. PMID:26996781

  6. Generalized energy failure criterion

    NASA Astrophysics Data System (ADS)

    Qu, R. T.; Zhang, Z. J.; Zhang, P.; Liu, Z. Q.; Zhang, Z. F.

    2016-03-01

    Discovering a generalized criterion that can predict the mechanical failure of various different structural materials is one of ultimate goals for scientists in both material and mechanics communities. Since the first study on the failure criterion of materials by Galileo, about three centuries have passed. Now we eventually find the “generalized energy criterion”, as presented here, which appears to be one universal law for various different kinds of materials. The validity of the energy criterion for quantitatively predicting the failure is experimentally confirmed using a metallic glass. The generalized energy criterion reveals the competition and interaction between shear and cleavage, the two fundamental inherent failure mechanisms, and thus provides new physical insights into the failure prediction of materials and structural components.

  7. Applicability of Jeans criterion.

    NASA Astrophysics Data System (ADS)

    Čadež, V.

    1995-03-01

    The applicability of the gravitational instability criterion is discussed for some typical configurations. It is shown that the small perturbation method has to be applied only locally, the reason being that the medium of a self-gravitating cloud cannot be considered as homogeneous throughout the whole space. Consequently, there is an upper limit to the geometrical size of a perturbation, defined by the typical inhomogeneity scale length L. On the other hand, according to Jeans criterion, the gravitational instability sets in for perturbations having their linear dimensions larger than some critical length LJ, the Jeans length. It is therefore of importance to estimate the value of the ratio L/LJ in order to be sure that the local analysis conclusions are meaningful.

  8. Unified Bohm criterion

    SciTech Connect

    Kos, L.; Tskhakaya, D. D.; Jelić, N.

    2015-09-15

    Recent decades have seen research into the conditions necessary for the formation of the monotonic potential shape in the sheath, appearing at the plasma boundaries like walls, in fluid, and kinetic approximations separately. Although either of these approaches yields a formulation commonly known as the much-acclaimed Bohm criterion (BC), the respective results involve essentially different physical quantities that describe the ion gas behavior. In the fluid approach, such a quantity is clearly identified as the ion directional velocity. In the kinetic approach, the ion behavior is formulated via a quantity (the squared inverse velocity averaged by the ion distribution function) without any clear physical significance, which is, moreover, impractical. In the present paper, we try to explain this difference by deriving a condition called here the Unified Bohm Criterion, which combines an advanced fluid model with an upgraded explicit kinetic formula in a new form of the BC. By introducing a generalized polytropic coefficient function, the unified BC can be interpreted in a form that holds, irrespective of whether the ions are described kinetically or in the fluid approximation.

  9. Probabilistic Threshold Criterion

    SciTech Connect

    Gresshoff, M; Hrousis, C A

    2010-03-09

    The Probabilistic Shock Threshold Criterion (PSTC) Project at LLNL develops phenomenological criteria for estimating safety or performance margin on high explosive (HE) initiation in the shock initiation regime, creating tools for safety assessment and design of initiation systems and HE trains in general. Until recently, there has been little foundation for probabilistic assessment of HE initiation scenarios. This work attempts to use probabilistic information that is available from both historic and ongoing tests to develop a basis for such assessment. Current PSTC approaches start with the functional form of the James Initiation Criterion as a backbone, and generalize to include varying areas of initiation and provide a probabilistic response based on test data for 1.8 g/cc (Ultrafine) 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and LX-17 (92.5% TATB, 7.5% Kel-F 800 binder). Application of the PSTC methodology is presented investigating the safety and performance of a flying plate detonator and the margin of an Ultrafine TATB booster initiating LX-17.

  10. Reduction criterion for separability

    NASA Astrophysics Data System (ADS)

    Cerf, N. J.; Adami, C.; Gingrich, R. M.

    1999-08-01

    We introduce a separability criterion based on the positive map Γ:ρ-->(Tr ρ)-ρ, where ρ is a trace-class Hermitian operator. Any separable state is mapped by the tensor product of Γ and the identity into a non-negative operator, which provides a simple necessary condition for separability. This condition is generally not sufficient because it is vulnerable to the dilution of entanglement. In the special case where one subsystem is a quantum bit, Γ reduces to time reversal, so that this separability condition is equivalent to partial transposition. It is therefore also sufficient for 2×2 and 2×3 systems. Finally, a simple connection between this map for two qubits and complex conjugation in the ``magic'' basis [Phys. Rev. Lett. 78, 5022 (1997)] is displayed.

  11. Use of distributed water level and soil moisture data in the evaluation of the PUMMA periurban distributed hydrological model: application to the Mercier catchment, France

    NASA Astrophysics Data System (ADS)

    Braud, Isabelle; Fuamba, Musandji; Branger, Flora; Batchabani, Essoyéké; Sanzana, Pedro; Sarrazin, Benoit; Jankowfsky, Sonja

    2016-04-01

    Distributed hydrological models are used at best when their outputs are compared not only to the outlet discharge, but also to internal observed variables, so that they can be used as powerful hypothesis-testing tools. In this paper, the interest of distributed networks of sensors for evaluating a distributed model and the underlying functioning hypotheses is explored. Two types of data are used: surface soil moisture and water level in streams. The model used in the study is the periurban PUMMA (Peri-Urban Model for landscape Management, Jankowfsky et al., 2014), that is applied to the Mercier catchment (6.7 km2) a semi-rural catchment with 14% imperviousness, located close to Lyon, France where distributed water level (13 locations) and surface soil moisture data (9 locations) are available. Model parameters are specified using in situ information or the results of previous studies, without any calibration and the model is run for four years from January 1st 2007 to December 31st 2010 with a variable time step for rainfall and an hourly time step for reference evapotranspiration. The model evaluation protocol was guided by the available data and how they can be interpreted in terms of hydrological processes and constraints for the model components and parameters. We followed a stepwise approach. The first step was a simple model water balance assessment, without comparison to observed data. It can be interpreted as a basic quality check for the model, ensuring that it conserves mass, makes the difference between dry and wet years, and reacts to rainfall events. The second step was an evaluation against observed discharge data at the outlet, using classical performance criteria. It gives a general picture of the model performance and allows to comparing it to other studies found in the literature. In the next steps (steps 3 to 6), focus was made on more specific hydrological processes. In step 3, distributed surface soil moisture data was used to assess the

  12. Generalized melting criterion for amorphization

    SciTech Connect

    Devanathan, R. |; Lam, N.Q.; Okamoto, P.R.; Meshii, M.

    1992-12-01

    We present a thermodynamic model of solid-state amorphization based on a generalization of the well-known Lindemann criterion. The original Lindemann criterion proposes that melting occurs when the root-mean-square amplitude of thermal displacement exceeds a critical value. This criterion can be generalized to include solid-state amorphization by taking into account the static displacements. In an effort to verify the generalized melting criterion, we have performed molecular dynamics simulations of radiation-induced amorphization in NiZr, NiZr{sub 2}, NiTi and FeTi using embedded-atom potentials. The average shear elastic constant G was calculated as a function of the total mean-square atomic displacement following random atom-exchanges and introduction of Frenkel pairs. Results provide strong support for the generalized melting criterion.

  13. Entropic criterion for model selection

    NASA Astrophysics Data System (ADS)

    Tseng, Chih-Yuan

    2006-10-01

    Model or variable selection is usually achieved through ranking models according to the increasing order of preference. One of methods is applying Kullback-Leibler distance or relative entropy as a selection criterion. Yet that will raise two questions, why use this criterion and are there any other criteria. Besides, conventional approaches require a reference prior, which is usually difficult to get. Following the logic of inductive inference proposed by Caticha [Relative entropy and inductive inference, in: G. Erickson, Y. Zhai (Eds.), Bayesian Inference and Maximum Entropy Methods in Science and Engineering, AIP Conference Proceedings, vol. 707, 2004 (available from arXiv.org/abs/physics/0311093)], we show relative entropy to be a unique criterion, which requires no prior information and can be applied to different fields. We examine this criterion by considering a physical problem, simple fluids, and results are promising.

  14. Criterion Reading Instructional Project (CRIP).

    ERIC Educational Resources Information Center

    Linden Board of Education, NJ.

    This booklet describes the Linden Title I Program between the years 1971-1974, with a focus on the Criterion Reading Instructional Project (CRIP). The program (in Linden, New Jersey) evolved from a supplemental reading and mathematics program to a structured developmental program of language arts designed to meet the needs of primary grade…

  15. Criterion-Referenced Measurement: Redirections.

    ERIC Educational Resources Information Center

    Ellett, Frederick S., Jr.

    Basic issues in criterion-referenced measurement are addressed. In section II, issues involved in determining what a person does and can do are considered. A preliminary analysis of "can" is given which shows that there are several important senses of "can". In section III, results of an analysis of "ability" are given. The analysis is used to…

  16. Bibliography on Criterion Referenced Measurement.

    ERIC Educational Resources Information Center

    Ellsworth, Randolph A.; Franz, Carleen

    This bibliography contains 262 references on Criterion Referenced Measurement (CRM) that were obtained from the following sources: (1) the author's personal files; (2) a bibliography compiled by Hsu and Boston (ERIC Document #ED 068 531) containing 52 references; (3) a bibliography compiled by Keller (ERIC Document #ED 060 041) containing 116…

  17. Extended equal area criterion revisited

    SciTech Connect

    Xue, X.; Wehenkel, L.; Belhomme, R.; Rousseaux, P.; Pavella, M. ); Euxibie, E.; Heilbronn, B.; Lesigne, J.F. )

    1992-08-01

    This paper reports on a case study conducted on the EHV French power system in order to revisit the extended equal area criterion and test its suitability as a fast transient stability indicator. The assumptions underlying the method are reexamined, causes liable to invalidate them are identified, and indices are devised to automatically circumvent them. The selection of candidate critical machines is also reconsidered and an augmented criterion is proposed. The various improvements are developed and tested on about 1000 stability scenarios, covering the entire 400-kV system; the severity of the scenarios, resulting from the combination of weakened both pre- and post-fault configurations, subjects the method to particularly stringent conditions. The obtained results show that the devised tools contribute to significantly reinforce its robustness and reliability.

  18. Counterexamples to the Sonic Criterion

    NASA Astrophysics Data System (ADS)

    Elling, Volker

    2009-12-01

    We consider self-similar (pseudo-steady) shock reflection at an oblique wall. There are three parameters: wall corner angle, Mach number, angle of incident shock. Ever since Ernst Mach discovered the irregular reflection named after him, researchers have sought to predict precisely for which parameters the reflection is regular. Three conflicting proposals—the detachment, sonic and von Neumann criteria—have been studied extensively without a clear result. We demonstrate that the sonic criterion is not correct. We consider polytropic potential flow and prove that there is an open nonempty set of parameters that admit a global regular reflection with a reflected shock that is transonic. We also provide a clear physical reason: the flow type (sub- or supersonic) is not decisive; instead the reflected shock type (weak or strong) determines whether structural perturbations decay towards the reflection point.

  19. An Operational Definition of the Emergence Criterion

    ERIC Educational Resources Information Center

    Pallotti, Gabriele

    2007-01-01

    Although acquisition criteria are a fundamental issue for SLA research, they have not always been adequately defined or elaborated in the literature. This article critically scrutinizes one such criterion, the emergence criterion, proposing an explicit, operational definition. After discussing emergence as a theoretical construct, the article…

  20. On a criterion for vortex breakdown

    NASA Technical Reports Server (NTRS)

    Spall, R. E.; Gatski, T. B.; Grosch, C. H.

    1987-01-01

    A criterion for the onset of vortex breakdown is proposed. Based upon previous experimental, computational, and theoretical studies, an appropriately defined local Rossby number is used to delineate the region where breakdown occurs. In addition, new numerical results are presented which further validate this criterion. A number of previous theoretical studies concentrating on inviscid standing-wave analyses for trailing wing-tip vortices are reviewed and reinterpreted in terms of the Rossby number criterion. Consistent with previous studies, the physical basis for the onset of breakdown is identified as the ability of the flow to sustain such waves. Previous computational results are reviewed and re-evaluated in terms of the proposed breakdown criterion. As a result, the cause of breakdown occurring near the inflow computational boundary, common to several numerical studies, is identified. Finally, previous experimental studies of vortex breakdown for both leading edge and trailing wing-tip vortices are reviewed and quantified in terms of the Rossby number criterion.

  1. An ethical criterion for geoscientists

    NASA Astrophysics Data System (ADS)

    Peppoloni, Silvia

    2013-04-01

    Anthropological researches have demonstrated that at some point in human history, man makes an evolutive jump in cultural sense: at first, he is able to perceive himself only as part of a community, later he becomes able to perceive himself as an individual. The analysis of the linguistic roots of the word "Ethics" discloses the traces of this evolutive transition and an original double meaning: on the one hand, "Ethics" contains a sense of belonging to the social fabric, on the other hand, it is related to the individual sphere. These two existential conditions (social and individual) unexpectedly co-exist in the word "Ethics". So, "Geo-Ethics" can be defined as the investigation and reflection on those values upon which to base appropriate behaviours and practices regarding the Geosphere (social dimension), but also as the analysis of the relationships between the geoscientist who acts and his own actions (individual dimension). Therefore, the meaning of the word "Geo-Ethics" calls upon geoscientists to face the responsibility of an ethical behaviour. What does this responsibility consist of and what motivations are necessary to push geoscientists to practice the Earth sciences in an ethical way? An ethical commitment exists if there is research of truth. In their activities, Geoscientists should be searchers and defenders of truth. If geoscientists give up this role, they completely empty of meaning their work. Ethical obligations arise from the possession of specific knowledge that has practical consequences. Geoscientists, as active and responsible part of society, have to serve society and the common good. The ethical criterion for a geoscientist should be rooted in his individual sphere, that is the source of any action even in the social sphere, and should have the intellectual honesty as main requirement. It includes: • respect for the truth that they look for and for other's ideas; • recognition of the value of others as valuable for themselves;

  2. Criterion for convection in an inhomogeneous star

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.; Chin, Chao-Wen

    1992-01-01

    To resolve the question of whether the Schwarzschild criterion or the Ledoux criterion should be used to test for convective instability in a star, a well-observed cluster of chemically inhomogeneous massive stars, in which the choice of the criterion for convection makes a crucial and easily observable difference, is required. NGC 330, a metal-poor cluster in the Small Magellanic Cloud, is ideal for this test. Its large evolved stellar population contains both blue and red supergiants, of which its many red supergiants should be absent if a gradient of mean molecular weight did not choke off rapid convective motions in the inhomogeneous region connecting the envelope and core. Thus the Ledoux criterion for convection is strongly indicated as being correct.

  3. A Quantitative Criterion for Defining Planets

    NASA Astrophysics Data System (ADS)

    Margot, Jean-Luc

    2015-12-01

    A simple metric can be used to determine whether a planet or exoplanet can clear its orbital zone during a characteristic time scale, such as the lifetime of the host star on the main sequence. This criterion requires only estimates of star mass, planet mass, and orbital period, making it possible to immediately classify 99% of all known exoplanets. All eight planets and all classifiable exoplanets satisfy the criterion. This metric may be useful in generalizing and simplifying the definition of a planet.

  4. A Quantitative Criterion for Defining Planets

    NASA Astrophysics Data System (ADS)

    Margot, J. L.

    2015-12-01

    A simple metric can be used to determine whether a planet or exoplanet can clear its orbital zone during a characteristic time scale, such as the lifetime of the host star on the main sequence. This criterion requires only estimates of star mass, planet mass, and orbital period, making it possible to immediately classify 99% of all known exoplanets. All 8 planets and all classifiable exoplanets satisfy the criterion. This metric may be useful in generalizing and simplifying the definition of a planet.

  5. The Extension of Convective Boundedness Criterion

    NASA Astrophysics Data System (ADS)

    Jian, Wu; Traoré, Philippe; Hubert, Romat

    2010-09-01

    The paper describes an extension of the well-known Convective Boundedness Criterion (CBC). It is shown that the newly proposed criterion is a combination of the CBC and the extended convective boundedness criterion (ECBC), as shown in Fig.1. A new scheme (NECBC1) based on the new criterion is designed and tested by two problems: (1) convection of a stepwise profile in an oblique uniform velocity field and (2) convection of an elliptical profile in a stagnation point flow. The numerical tests show the effectiveness of the new criterion and reveal the limitation of the CBC and the ECBC. Moreover, some numerical experiments of some specially-designed schemes and two TVD-Type schemes: the van Albada scheme and Miroslav Čada & Manuel Torrilhon's new third-order scheme, are carried out. Through these numerical experiments, some extra constraints for the new criterion are observed and in the meantime some other possible regions in the normalized diagram (NV) for high-resolution schemes reveal themselves.

  6. Resilience as a universal criterion of health.

    PubMed

    Döring, Thomas F; Vieweger, Anja; Pautasso, Marco; Vaarst, Mette; Finckh, Maria R; Wolfe, Martin S

    2015-02-01

    To promote and maintain health in agricultural and food systems, appropriate criteria are needed for the description and assessment of the health of soils, plants, animals, humans and ecosystems. Here we identify the concept of resilience as a universally applicable and fundamentally important criterion of health in all relevant areas of agriculture. We discuss definitions of resilience for soils, plants, animals, humans and ecosystems, and explore ways in which resilience can be applied as a criterion of health in different agricultural contexts. We show how and why resilience can be seen as a key criterion of health. Based on this, we discuss how resilience can be used as a link between soil, plant, animal, human and ecosystem health. Finally, we highlight four key areas for future research on resilience in agriculture, namely spatial and temporal scaling of resilience; effects of diversity; the role of networks for resilience; and stakeholder involvement. PMID:24343565

  7. Filamentary and hierarchical pictures - Kinetic energy criterion

    NASA Technical Reports Server (NTRS)

    Klypin, Anatoly A.; Melott, Adrian L.

    1992-01-01

    We present a new criterion for formation of second-generation filaments. The criterion called the kinetic energy ratio, KR, is based on comparison of peculiar velocities at different scales. We suggest that the clumpiness of the distribution in some cases might be less important than the 'coldness' or 'hotness' of the flow for formation of coherent structures. The kinetic energy ratio is analogous to the Mach number except for one essential difference. If at some scale KR is greater than 1, as estimated at the linear stage, then when fluctuations of this scale reach nonlinearity, the objects they produce must be anisotropic ('filamentary'). In the case of power-law initial spectra the kinetic ratio criterion suggests that the border line is the power-spectrum with the slope n = -1.

  8. Criterion-Referenced Test Items for Welding.

    ERIC Educational Resources Information Center

    Davis, Diane, Ed.

    This test item bank on welding contains test questions based upon competencies found in the Missouri Welding Competency Profile. Some test items are keyed for multiple competencies. These criterion-referenced test items are designed to work with the Vocational Instructional Management System. Questions have been statistically sampled and validated…

  9. Aging: Sensitivity versus Criterion in Taste Perception.

    ERIC Educational Resources Information Center

    Kushnir, T.; Shapira, N.

    1983-01-01

    Employed the signal-detection paradigm as a model for investigating age-related biological versus cognitive effects on perceptual behavior. Old and young subjects reported the presence or absence of sugar in threshold level solutions and tap water. Older subjects displayed a higher detection threshold and obtained a stricter criterion of decision.…

  10. Criterion vs. Norm-referenced Testing.

    ERIC Educational Resources Information Center

    Pimsleur, Paul

    1975-01-01

    A norm-referenced evaluation system, which evaluates the student in comparison to his peers, is rejected in favor of a criterion-referenced system. The latter, which rates the performance of a student on an absolute standard, makes for an individualized approach. Two kinds of tests are distinguished, the formative, administered during the course…

  11. An aerodynamic load criterion for airships

    NASA Technical Reports Server (NTRS)

    Woodward, D. E.

    1975-01-01

    A simple aerodynamic bending moment envelope is derived for conventionally shaped airships. This criterion is intended to be used, much like the Naval Architect's standard wave, for preliminary estimates of longitudinal strength requirements. It should be useful in tradeoff studies between speed, fineness ratio, block coefficient, structure weight, and other such general parameters of airship design.

  12. Contrasting Norm Referenced and Criterion Referenced Measures.

    ERIC Educational Resources Information Center

    Randall, Robert S.

    Differences in design between norm referenced measures (NRM) and criterion referenced measures (CRM) are reviewed, and some of the procedures proposed on designing and evaluating CRM are examined. Differences in design of NRM and CRM are said to arise from the different purposes that underlie each measure. In addition, there are differences among…

  13. Selecting Items for Criterion-Referenced Tests.

    ERIC Educational Resources Information Center

    Mellenbergh, Gideon J.; van der Linden, Wim J.

    1982-01-01

    Three item selection methods for criterion-referenced tests are examined: the classical theory of item difficulty and item-test correlation; the latent trait theory of item characteristic curves; and a decision-theoretic approach for optimal item selection. Item contribution to the standardized expected utility of mastery testing is discussed. (CM)

  14. Evaluating Criterion-referenced Tests. ERIC Digest.

    ERIC Educational Resources Information Center

    Hambleton, Ronald K.

    Criterion-referenced tests (CRTs) are constructed to permit the interpretation of examinee tests performance in relation to a set of well-defined competencies. CRTs are currently used extensively in schools, industry, and the armed services because they provide valuable and different information from norm-referenced tests. Test publishers, school…

  15. The definition and criterion of death.

    PubMed

    Bernat, James L

    2013-01-01

    The definition and criterion of death have been rendered ambiguous by developments in organ support technology, particularly the positive-pressure ventilator and vasopressor medications, that uncouple the unitary loss of vital functions in death and create cases in which the brain has been destroyed while circulation and ventilation can be supported. Developing a biophilosophic analysis of the meaning of death before physicians can declare it requires four sequential steps: (1) agreement on the paradigm conditions that frame the analysis and clarify the task; (2) identifying the definition of death, which makes explicit the meaning of death that is accepted in our consensual usage of the term but that has become obscured by technology; (3) identifying the criterion of death that shows that the definition has been fulfilled, and that can be incorporated into a death statute; and (4) devising bedside tests of death for physicians to perform to satisfy the criterion. Although there is a strong consensus on death determination medical standards in countries around the world that has been enshrined into laws, and accepted by most societies and religions, there remains an active dispute among scholars on the precise definition and criterion of death. PMID:24182395

  16. Jeans' criterion in nonextensive statistical mechanics

    NASA Astrophysics Data System (ADS)

    Jiulin, Du

    2004-04-01

    The Jeans' gravitational instability in nonextensive statistical mechanics is studied and a general form of the generalized Jeans' criterion is obtained that is related to the q-function cq=∑ipiq. In this approach, the nonextensive model of classical ideal gas is applied to the Jeans' problem instead of the ordinary one in extensive statistical mechanics and the generalized critical wavelength to describe the gravitational instability is deduced. This nonextensive modification of the Jeans' criterion leads to a new critical length that depends not only on the nonextensive parameter q but also on the dimension D and the total particle numbers N of the system. When q-->1-, the Jeans' length is perfectly recovered. We also give the nonextensive parameter q a physical interpretation that q=1 represents an isothermal process of the gas, corresponding to the state of complete mixing, but 0

  17. Stochastic Games with Average Payoff Criterion

    SciTech Connect

    Ghosh, M. K.; Bagchi, A.

    1998-11-15

    We study two-person stochastic games on a Polish state and compact action spaces and with average payoff criterion under a certain ergodicity condition. For the zero-sum game we establish the existence of a value and stationary optimal strategies for both players. For the nonzero-sum case the existence of Nash equilibrium in stationary strategies is established under certain separability conditions.

  18. On the hodological criterion for homology

    PubMed Central

    Faunes, Macarena; Francisco Botelho, João; Ahumada Galleguillos, Patricio; Mpodozis, Jorge

    2015-01-01

    Owen's pre-evolutionary definition of a homolog as “the same organ in different animals under every variety of form and function” and its redefinition after Darwin as “the same trait in different lineages due to common ancestry” entail the same heuristic problem: how to establish “sameness.”Although different criteria for homology often conflict, there is currently a generalized acceptance of gene expression as the best criterion. This gene-centered view of homology results from a reductionist and preformationist concept of living beings. Here, we adopt an alternative organismic-epigenetic viewpoint, and conceive living beings as systems whose identity is given by the dynamic interactions between their components at their multiple levels of composition. We posit that there cannot be an absolute homology criterion, and instead, homology should be inferred from comparisons at the levels and developmental stages where the delimitation of the compared trait lies. In this line, we argue that neural connectivity, i.e., the hodological criterion, should prevail in the determination of homologies between brain supra-cellular structures, such as the vertebrate pallium. PMID:26157357

  19. Regularization Parameter Selections via Generalized Information Criterion

    PubMed Central

    Zhang, Yiyun; Li, Runze; Tsai, Chih-Ling

    2009-01-01

    We apply the nonconcave penalized likelihood approach to obtain variable selections as well as shrinkage estimators. This approach relies heavily on the choice of regularization parameter, which controls the model complexity. In this paper, we propose employing the generalized information criterion (GIC), encompassing the commonly used Akaike information criterion (AIC) and Bayesian information criterion (BIC), for selecting the regularization parameter. Our proposal makes a connection between the classical variable selection criteria and the regularization parameter selections for the nonconcave penalized likelihood approaches. We show that the BIC-type selector enables identification of the true model consistently, and the resulting estimator possesses the oracle property in the terminology of Fan and Li (2001). In contrast, however, the AIC-type selector tends to overfit with positive probability. We further show that the AIC-type selector is asymptotically loss efficient, while the BIC-type selector is not. Our simulation results confirm these theoretical findings, and an empirical example is presented. Some technical proofs are given in the online supplementary material. PMID:20676354

  20. On the hodological criterion for homology.

    PubMed

    Faunes, Macarena; Francisco Botelho, João; Ahumada Galleguillos, Patricio; Mpodozis, Jorge

    2015-01-01

    Owen's pre-evolutionary definition of a homolog as "the same organ in different animals under every variety of form and function" and its redefinition after Darwin as "the same trait in different lineages due to common ancestry" entail the same heuristic problem: how to establish "sameness."Although different criteria for homology often conflict, there is currently a generalized acceptance of gene expression as the best criterion. This gene-centered view of homology results from a reductionist and preformationist concept of living beings. Here, we adopt an alternative organismic-epigenetic viewpoint, and conceive living beings as systems whose identity is given by the dynamic interactions between their components at their multiple levels of composition. We posit that there cannot be an absolute homology criterion, and instead, homology should be inferred from comparisons at the levels and developmental stages where the delimitation of the compared trait lies. In this line, we argue that neural connectivity, i.e., the hodological criterion, should prevail in the determination of homologies between brain supra-cellular structures, such as the vertebrate pallium. PMID:26157357

  1. A Rosenzweig-MacArthur (1963) Criterion for the Chemostat

    PubMed Central

    Cheng, Yuanji

    2016-01-01

    The Rosenzweig-MacArthur (1963) criterion is a graphical criterion that has been widely used for elucidating the local stability properties of the Gause (1934) type predator-prey systems. It has not been stated whether a similar criterion holds for models with explicit resource dynamics (Kooi et al. (1998)), like the chemostat model. In this paper we use the implicit function theorem and implicit derivatives for proving that a similar graphical criterion holds under chemostat conditions, too. PMID:27517080

  2. Beating the Stoner criterion using molecular interfaces

    NASA Astrophysics Data System (ADS)

    Ma'Mari, Fatma Al; Moorsom, Timothy; Teobaldi, Gilberto; Deacon, William; Prokscha, Thomas; Luetkens, Hubertus; Lee, Steve; Sterbinsky, George E.; Arena, Dario A.; MacLaren, Donald A.; Flokstra, Machiel; Ali, Mannan; Wheeler, May C.; Burnell, Gavin; Hickey, Bryan J.; Cespedes, Oscar

    2015-08-01

    Only three elements are ferromagnetic at room temperature: the transition metals iron, cobalt and nickel. The Stoner criterion explains why iron is ferromagnetic but manganese, for example, is not, even though both elements have an unfilled 3d shell and are adjacent in the periodic table: according to this criterion, the product of the density of states and the exchange integral must be greater than unity for spontaneous spin ordering to emerge. Here we demonstrate that it is possible to alter the electronic states of non-ferromagnetic materials, such as diamagnetic copper and paramagnetic manganese, to overcome the Stoner criterion and make them ferromagnetic at room temperature. This effect is achieved via interfaces between metallic thin films and C60 molecular layers. The emergent ferromagnetic state exists over several layers of the metal before being quenched at large sample thicknesses by the material's bulk properties. Although the induced magnetization is easily measurable by magnetometry, low-energy muon spin spectroscopy provides insight into its distribution by studying the depolarization process of low-energy muons implanted in the sample. This technique indicates localized spin-ordered states at, and close to, the metal-molecule interface. Density functional theory simulations suggest a mechanism based on magnetic hardening of the metal atoms, owing to electron transfer. This mechanism might allow for the exploitation of molecular coupling to design magnetic metamaterials using abundant, non-toxic components such as organic semiconductors. Charge transfer at molecular interfaces may thus be used to control spin polarization or magnetization, with consequences for the design of devices for electronic, power or computing applications (see, for example, refs 6 and 7).

  3. Beating the Stoner criterion using molecular interfaces.

    PubMed

    Ma'Mari, Fatma Al; Moorsom, Timothy; Teobaldi, Gilberto; Deacon, William; Prokscha, Thomas; Luetkens, Hubertus; Lee, Steve; Sterbinsky, George E; Arena, Dario A; MacLaren, Donald A; Flokstra, Machiel; Ali, Mannan; Wheeler, May C; Burnell, Gavin; Hickey, Bryan J; Cespedes, Oscar

    2015-08-01

    Only three elements are ferromagnetic at room temperature: the transition metals iron, cobalt and nickel. The Stoner criterion explains why iron is ferromagnetic but manganese, for example, is not, even though both elements have an unfilled 3d shell and are adjacent in the periodic table: according to this criterion, the product of the density of states and the exchange integral must be greater than unity for spontaneous spin ordering to emerge. Here we demonstrate that it is possible to alter the electronic states of non-ferromagnetic materials, such as diamagnetic copper and paramagnetic manganese, to overcome the Stoner criterion and make them ferromagnetic at room temperature. This effect is achieved via interfaces between metallic thin films and C60 molecular layers. The emergent ferromagnetic state exists over several layers of the metal before being quenched at large sample thicknesses by the material's bulk properties. Although the induced magnetization is easily measurable by magnetometry, low-energy muon spin spectroscopy provides insight into its distribution by studying the depolarization process of low-energy muons implanted in the sample. This technique indicates localized spin-ordered states at, and close to, the metal-molecule interface. Density functional theory simulations suggest a mechanism based on magnetic hardening of the metal atoms, owing to electron transfer. This mechanism might allow for the exploitation of molecular coupling to design magnetic metamaterials using abundant, non-toxic components such as organic semiconductors. Charge transfer at molecular interfaces may thus be used to control spin polarization or magnetization, with consequences for the design of devices for electronic, power or computing applications (see, for example, refs 6 and 7). PMID:26245580

  4. A criterion autoscheduler for long range planning

    NASA Technical Reports Server (NTRS)

    Sponsler, Jeffrey L.

    1994-01-01

    A constraint-based scheduling system called SPIKE is used to create long-term schedules for the Hubble Space Telescope. A meta-level scheduler called the Criterion Autoscheduler for Long range planning (CASL) was created to guide SPIKE's schedule generation according to the agenda of the planning scientists. It is proposed that sufficient flexibility exists in a schedule to allow high level planning heuristics to be applied without adversely affected crucial constraints such as spacecraft efficiency. This hypothesis is supported by test data which is described.

  5. Generalized Bohm Criterion for Electronegative Complex Plasma

    SciTech Connect

    Chekour, S.; Tahraoui, A.

    2011-11-29

    In this work, we have generalized the computation of Bohm criterion for electronegative complex plasma. For this, we have established a one-dimensional, unmagnetized and stationary theoretical model where the positive ions and dust particles are modeled by fluid equations. The electrons and negative ions are considered in thermodynamic equilibrium; therefore they obey to Boltzmann's statistic. In this case, the numerical results show that the generalized Bohm velocity is small compared to the classical value. For electronegative dusty plasma, the corrections are less important.

  6. Criterion-Referenced Testing in Foreign Language Teaching.

    ERIC Educational Resources Information Center

    Takala, Sauli

    A review of literature serves as the basis for a discussion of various aspects of criterion-referenced tests. The aspects discussed are: teaching and evaluation objectives, criterion- and norm-referenced measurement, stages in construction of criterion-referenced tests, construction and selection of items, test validity, and test reliability.…

  7. A Quantitative Criterion for Defining Planets

    NASA Astrophysics Data System (ADS)

    Margot, Jean-Luc

    2015-11-01

    The IAU definition of 'planet' needs improvement because it is neither quantitative nor general. The current definition applies only to solar system bodies and does not allow for the classification of exoplanets. The current definition can also be misunderstood or misconstrued because of its qualitative nature (e.g., "has cleared the neighbourhood around its orbit").A simple metric can be used to determine whether a planet or exoplanet can clear its orbital zone during a characteristic time scale, such as the lifetime of the host star on the main sequence. This criterion requires only estimates of star mass, planet mass, and orbital period, making it possible to immediately classify 99% of all known exoplanets. All 8 planets and all classifiable exoplanets satisfy the criterion.I will describe the development of the metric and apply it to solar system bodies, exoplanets, and pulsar planets. I will then show how this metric could be used to quantify, generalize, and simplify the definition of 'planet'. A preprint is available at http://arxiv.org/abs/1507.06300

  8. Extensions and applications of the Bohm criterion

    NASA Astrophysics Data System (ADS)

    Baalrud, Scott D.; Scheiner, Brett; Yee, Benjamin; Hopkins, Matthew; Barnat, Edward

    2015-04-01

    The generalized Bohm criterion is revisited in the context of incorporating kinetic effects of the electron and ion distribution functions into the theory. The underlying assumptions and results of two different approaches are compared: the conventional ‘kinetic Bohm criterion’ and a fluid-moment hierarchy approach. The former is based on the asymptotic limit of an infinitely thin sheath (λD/l = 0), whereas the latter is based on a perturbative expansion of a sheath that is thin compared to the plasma (λD/l ≪ 1). Here λD is the Debye length, which characterizes the sheath length scale, and l is a measure of the plasma or presheath length scale. The consequences of these assumptions are discussed in terms of how they restrict the class of distribution functions to which the resulting criteria can be applied. Two examples are considered to provide concrete comparisons between the two approaches. The first is a Tonks-Langmuir model including a warm ion source (Robertson 2009 Phys. Plasmas 16 103503). This highlights a substantial difference between the conventional kinetic theory, which predicts slow ions dominate at the sheath edge, and the fluid moment approach, which predicts slow ions have little influence. The second example considers planar electrostatic probes biased near the plasma potential using model equations and particle-in-cell simulations. This demonstrates a situation where electron kinetic effects alter the Bohm criterion, leading to a subsonic ion flow at the sheath edge.

  9. A universal fracture criterion for high-strength materials

    PubMed Central

    Qu, Rui Tao; Zhang, Zhe Feng

    2013-01-01

    Recently developed advanced high-strength materials like metallic glasses, nanocrystalline metallic materials, and advanced ceramics usually fracture in a catastrophic brittle manner, which makes it quite essential to find a reasonable fracture criterion to predict their brittle failure behaviors. Based on the analysis of substantial experimental observations of fracture behaviors of metallic glasses and other high-strength materials, here we developed a new fracture criterion and proved it effective in predicting the critical fracture conditions under complex stress states. The new criterion is not only a unified one which unifies the three classical failure criteria, i.e., the maximum normal stress criterion, the Tresca criterion and the Mohr-Coulomb criterion, but also a universal criterion which has the ability to describe the fracture mechanisms of a variety of different high-strength materials under various external loading conditions.

  10. Nash equilibrium and multi criterion aerodynamic optimization

    NASA Astrophysics Data System (ADS)

    Tang, Zhili; Zhang, Lianhe

    2016-06-01

    Game theory and its particular Nash Equilibrium (NE) are gaining importance in solving Multi Criterion Optimization (MCO) in engineering problems over the past decade. The solution of a MCO problem can be viewed as a NE under the concept of competitive games. This paper surveyed/proposed four efficient algorithms for calculating a NE of a MCO problem. Existence and equivalence of the solution are analyzed and proved in the paper based on fixed point theorem. Specific virtual symmetric Nash game is also presented to set up an optimization strategy for single objective optimization problems. Two numerical examples are presented to verify proposed algorithms. One is mathematical functions' optimization to illustrate detailed numerical procedures of algorithms, the other is aerodynamic drag reduction of civil transport wing fuselage configuration by using virtual game. The successful application validates efficiency of algorithms in solving complex aerodynamic optimization problem.

  11. Generalized reduction criterion for separability of quantum states

    NASA Astrophysics Data System (ADS)

    Albeverio, Sergio; Chen, Kai; Fei, Shao-Ming

    2003-12-01

    A necessary separability criterion that relates the structures of the total density matrix and its reductions is given. The method used is based on the realignment method [K. Chen and L. A. Wu, Quant. Inf. Comput. 3, 193 (2003)]. The separability criterion naturally generalizes the reduction separability criterion introduced independently in the previous work [M. Horodecki and P. Horodecki, Phys. Rev. A 59, 4206 (1999) and N. J. Cerf, C. Adami, and R. M. Gingrich, Phys. Rev. A 60, 898 (1999)]. In special cases, it recovers the previous reduction criterion and the recent generalized partial transposition criterion [K. Chen and L. A. Wu, Phys. Lett. A 306, 14 (2002)]. The criterion involves only simple matrix manipulations and can therefore be easily applied.

  12. The NT-criterion for predicting crack growth increments

    NASA Technical Reports Server (NTRS)

    Yehia, Nabil A. B.; Shephard, Mark S.

    1987-01-01

    A new approach is presented to determine the crack propagation increment after the direction of crack propagation has been predicted. The maximum dilatational strain energy density (NT-criterion) is employed in the derivation for predicting both direction and increment of the propagating crack. The crack propagation path predicted by the NT-criterion is compared to the one predicted by the S-criterion and to some available experimental data.

  13. A proposed criterion for aircraft flight in turbulence

    NASA Technical Reports Server (NTRS)

    Porter, R. F.; Robinson, A. C.

    1971-01-01

    A proposed criterion for aircraft flight in turbulent conditions is presented. Subjects discussed are: (1) the problem of flight safety in turbulence, (2) new criterion for turbulence flight where existing ones seem adequate, and (3) computational problems associated with new criterion. Primary emphasis is placed on catastrophic occurrences in subsonic cruise with the aircraft under automatic control. A Monte Carlo simulation is used in the formulation and evaluation of probabilities of survival of an encounter with turbulence.

  14. An Independent and Coordinated Criterion for Kinematic Aircraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Narkawicz, Anthony J.; Munoz, Cesar A.; Hagen, George

    2014-01-01

    This paper proposes a mathematical definition of an aircraft-separation criterion for kinematic-based horizontal maneuvers. It has been formally proved that kinematic maneu- vers that satisfy the new criterion are independent and coordinated for repulsiveness, i.e., the distance at closest point of approach increases whether one or both aircraft maneuver according to the criterion. The proposed criterion is currently used in NASA's Airborne Coordinated Resolution and Detection (ACCoRD) set of tools for the design and analysis of separation assurance systems.

  15. A stochastic T cell response criterion

    PubMed Central

    Currie, James; Castro, Mario; Lythe, Grant; Palmer, Ed; Molina-París, Carmen

    2012-01-01

    The adaptive immune system relies on different cell types to provide fast and coordinated responses, characterized by recognition of pathogenic challenge, extensive cellular proliferation and differentiation, as well as death. T cells are a subset of the adaptive immune cellular pool that recognize immunogenic peptides expressed on the surface of antigen-presenting cells by means of specialized receptors on their membrane. T cell receptor binding to ligand determines T cell responses at different times and locations during the life of a T cell. Current experimental evidence provides support to the following: (i) sufficiently long receptor–ligand engagements are required to initiate the T cell signalling cascade that results in productive signal transduction and (ii) counting devices are at work in T cells to allow signal accumulation, decoding and translation into biological responses. In the light of these results, we explore, with mathematical models, the timescales associated with T cell responses. We consider two different criteria: a stochastic one (the mean time it takes to have had N receptor–ligand complexes bound for at least a dwell time, τ, each) and one based on equilibrium (the time to reach a threshold number N of receptor–ligand complexes). We have applied mathematical models to previous experiments in the context of thymic negative selection and to recent two-dimensional experiments. Our results indicate that the stochastic criterion provides support to the thymic affinity threshold hypothesis, whereas the equilibrium one does not, and agrees with the ligand hierarchy experimentally established for thymic negative selection. PMID:22745227

  16. Jeans criterion in a turbulent medium

    NASA Technical Reports Server (NTRS)

    Bonazzola, S.; Falgarone, E.; Heyvaerts, J.; Perault, M.; Puget, J. L.

    1986-01-01

    According to the classical Jeans analysis, all the molecular clouds of mass larger than a few 100 M(solar), size larger than about 1pc and kinetic temperature Tk less than 30K are gravitationally unstable. We have shown that in clouds supported by internal supersonic motions, local gravitational instabilities may appear within molecular clouds which are globally stable. The argument is threefold: (1) when the turbulent kinetic energy is included into the internal energy term, the virial equilibrium condition shows that molecular clouds such as those observed, which are gravitationally unstable according to the Jeans criterion, are indeed globally stable if supported by a turbulent velocity field of power spectrum steeper than 3; (2) 2D compressible hydrodynamical simulations show that a supersonic turbulent velocity field generates a turbulent pressure within clouds, the gradients of which stabilize the unstable scales (i.e., the largest scales and the cloud itself) against gravitational collapse; (3) an analysis similar to the Jeans approach but including the turbulent pressure gradient term, gives basically the same results as those given in (1). Clouds of mean density lower than a critical value are found to be stable even though more massive than their Jeans mass. In clouds of mean density larger than that critical value, the gravitational instability appears only over a range of scales smaller than the cloud size, the largest scales being stable. In practice, the observed mean densities are lower than this critical value: the observation of a small number of cores and stars of a few solar masses embedded in clouds of several hundred solar masses can only be understood in terms of small scale density fluctuations of large amplitude generated by the supersonic turbulence which would occasionally overtake the limit of gravitational stability.

  17. Jeans criterion in a turbulent medium

    NASA Astrophysics Data System (ADS)

    Bonazzola, S.; Falgarone, E.; Heyvaerts, J.; Perault, M.; Puget, J. L.

    1986-10-01

    According to the classical Jeans analysis, all the molecular clouds of mass larger than a few 100 M(solar), size larger than about 1pc and kinetic temperature Tk less than 30K are gravitationally unstable. We have shown that in clouds supported by internal supersonic motions, local gravitational instabilities may appear within molecular clouds which are globally stable. The argument is threefold: (1) when the turbulent kinetic energy is included into the internal energy term, the virial equilibrium condition shows that molecular clouds such as those observed, which are gravitationally unstable according to the Jeans criterion, are indeed globally stable if supported by a turbulent velocity field of power spectrum steeper than 3; (2) 2D compressible hydrodynamical simulations show that a supersonic turbulent velocity field generates a turbulent pressure within clouds, the gradients of which stabilize the unstable scales (i.e., the largest scales and the cloud itself) against gravitational collapse; (3) an analysis similar to the Jeans approach but including the turbulent pressure gradient term, gives basically the same results as those given in (1). Clouds of mean density lower than a critical value are found to be stable even though more massive than their Jeans mass. In clouds of mean density larger than that critical value, the gravitational instability appears only over a range of scales smaller than the cloud size, the largest scales being stable. In practice, the observed mean densities are lower than this critical value: the observation of a small number of cores and stars of a few solar masses embedded in clouds of several hundred solar masses can only be understood in terms of small scale density fluctuations of large amplitude generated by the supersonic turbulence which would occasionally overtake the limit of gravitational stability.

  18. The Epistemic Criterion: A Response to Michael Hand

    ERIC Educational Resources Information Center

    Cooling, Trevor

    2014-01-01

    This article is a response to Michael Hand's critique in this issue of my response to his use of the epistemic criterion as the sole means for identifying whether or not an issue should be identified as controversial. I argue that he has misunderstood my intention in suggesting that I was seeking to replace the epistemic criterion. Rather my…

  19. Criterion-Related Validity: Assessing the Value of Subscores

    ERIC Educational Resources Information Center

    Davison, Mark L.; Davenport, Ernest C., Jr.; Chang, Yu-Feng; Vue, Kory; Su, Shiyang

    2015-01-01

    Criterion-related profile analysis (CPA) can be used to assess whether subscores of a test or test battery account for more criterion variance than does a single total score. Application of CPA to subscore evaluation is described, compared to alternative procedures, and illustrated using SAT data. Considerations other than validity and reliability…

  20. Criterion for faithful teleportation with an arbitrary multiparticle channel

    NASA Astrophysics Data System (ADS)

    Cheung, Chi-Yee; Zhang, Zhan-Jun

    2009-08-01

    We present a general criterion which allows one to judge if an arbitrary multiparticle entanglement channel can be used to teleport faithfully an unknown quantum state of a given dimension. We also present a general multiparticle teleportation protocol which is applicable for all channel states satisfying this criterion.

  1. Criterion-Referenced Measurement: Half a Century Wasted?

    ERIC Educational Resources Information Center

    Popham, W. James

    2014-01-01

    Fifty years ago, Robert Glaser introduced the concept of criterion-referenced measurement in an article in American Psychologist. Its early proponents predicted that this measurement strategy would revolutionize education. But has it lived up to its promise? W. James Popham explores this question by looking at the history of criterion-referenced…

  2. Criterion Referenced Testing: A Bibliography. TM Report 53.

    ERIC Educational Resources Information Center

    Porter, Deborah Elena

    Within the last decade, a wealth of literature has appeared debating the merits, use, construction, and interpretation of criterion referenced tests. This is a bibliography of articles on a wide range of topics on criterion referenced testing subjects. Also included are articles on mastery and domain referenced testing. The articles cited were…

  3. Criterion to Evaluate the Quality of Infrared Small Target Images

    NASA Astrophysics Data System (ADS)

    Mao, Xia; Diao, Wei-He

    2009-01-01

    In this paper, we propose a new criterion to estimate the quality of infrared small target images. To describe the criterion quantitatively, two indicators are defined. One is the “degree of target being confused” that represents the ability of infrared small target image to provide fake targets. The other one is the “degree of target being shielded”, which reflects the contribution of the image to shield the target. Experimental results reveal that this criterion is more robust than the traditional method (Signal-to-Noise Ratio). It is not only valid to infrared small target images which Signal-to-Noise Ratio could correctly describe, but also to the images that the traditional criterion could not accurately estimate. In addition, the results of this criterion can provide information about the cause of background interfering with target detection.

  4. Failure Criterion for Brick Masonry: A Micro-Mechanics Approach

    NASA Astrophysics Data System (ADS)

    Kawa, Marek

    2015-02-01

    The paper deals with the formulation of failure criterion for an in-plane loaded masonry. Using micro-mechanics approach the strength estimation for masonry microstructure with constituents obeying the Drucker-Prager criterion is determined numerically. The procedure invokes lower bound analysis: for assumed stress fields constructed within masonry periodic cell critical load is obtained as a solution of constrained optimization problem. The analysis is carried out for many different loading conditions at different orientations of bed joints. The performance of the approach is verified against solutions obtained for corresponding layered and block microstructures, which provides the upper and lower strength bounds for masonry microstructure, respectively. Subsequently, a phenomenological anisotropic strength criterion for masonry microstructure is proposed. The criterion has a form of conjunction of Jaeger critical plane condition and Tsai-Wu criterion. The model proposed is identified based on the fitting of numerical results obtained from the microstructural analysis. Identified criterion is then verified against results obtained for different loading orientations. It appears that strength of masonry microstructure can be satisfactorily described by the criterion proposed.

  5. A nonlinear criterion for triaxial strength of inherently anisotropic rocks

    NASA Astrophysics Data System (ADS)

    Singh, Mahendra; Samadhiya, N. K.; Kumar, Ajit; Kumar, Vivek; Singh, Bhawani

    2015-07-01

    Rocks encountered at many underground construction sites are laminated and exhibit direction-dependent strength behavior. It is also a well-established fact that the strength varies in a nonlinear manner with confining pressure. There is a need of strength criterion which could capture the nonlinearity as well as the anisotropy in the triaxial strength behavior of the rocks. It is essential that the criterion should be simple and must involve minimum testing to the extent possible. Further, the parameters of the criterion should have wide acceptability among the geotechnical fraternity. In the present study, a nonlinear strength criterion for transversely isotropic rocks is presented. Critical state concept Barton (Int J Rock Mech Mining Sci Geomech Abstr 13(9):255-279, 1976) has been used to define the curvature of the criterion. With a correctly defined curvature and starting from a reference point (UCS), it is possible to accurately assess the triaxial strength for given confining pressure. An experimental study conducted on triaxial strength behavior of three types of anisotropic rocks namely phyllite, slate and orthoquartzite has been discussed. A data base comprising more than 1140 triaxial tests conducted worldwide on anisotropic rocks has been compiled. Statistical evaluation of goodness of fit of the proposed criterion to the data base has been carried out. Further, the predictive capabilities of the proposed criterion have been evaluated by determining the error in estimation of triaxial strength if only few triaxial test data are available for determining the criterion parameters. The data base has also been back analyzed to assess the critical confining pressure for anisotropic rocks. Statistically, the critical confining pressure for anisotropic rocks can be taken nearly equal to 1.25 times the maximum UCS (obtained by applying load either parallel or perpendicular to planes of anisotropy). It is concluded that reasonable estimates of the triaxial

  6. Application of G criterion in metal vapor ion laser

    NASA Astrophysics Data System (ADS)

    Gang, Chen; Bailiang, Pan; Yi, Jin; Kun, Chen; Zhixin, Yao

    2003-09-01

    Application of G criterion to efficient operation of pulsed discharge-excited R-M transition metal vapor laser was successfully extended to univalent ionic lasing medium from neutral atomic lasing medium on the basis of analyzing the simulation results of 1.09 μm Sr + lasing process. All of the known 17 R-M transition laser lines of univalent ions follow the G criterion except one, to which an interpretation is given. Furthermore, we suggest that only 69 lines among 212 possible R-M transition laser lines predicted by S.V. Markova, which satisfy the G criterion, should be explored first.

  7. On the reduction criterion for random quantum states

    SciTech Connect

    Jivulescu, Maria Anastasia Lupa, Nicolae; Nechita, Ion

    2014-11-15

    In this paper, we study the reduction criterion for detecting entanglement of large dimensional bipartite quantum systems. We first obtain an explicit formula for the moments of a random quantum state to which the reduction criterion has been applied. We show that the empirical eigenvalue distribution of this random matrix converges strongly to a limit that we compute, in three different asymptotic regimes. We then employ tools from free probability theory to study the asymptotic positivity of the reduction operators. Finally, we compare the reduction criterion with other entanglement criteria, via thresholds.

  8. Energy Criterion for the Spectral Stability of Discrete Breathers.

    PubMed

    Kevrekidis, Panayotis G; Cuevas-Maraver, Jesús; Pelinovsky, Dmitry E

    2016-08-26

    Discrete breathers are ubiquitous structures in nonlinear anharmonic models ranging from the prototypical example of the Fermi-Pasta-Ulam model to Klein-Gordon nonlinear lattices, among many others. We propose a general criterion for the emergence of instabilities of discrete breathers analogous to the well-established Vakhitov-Kolokolov criterion for solitary waves. The criterion involves the change of monotonicity of the discrete breather's energy as a function of the breather frequency. Our analysis suggests and numerical results corroborate that breathers with increasing (decreasing) energy-frequency dependence are generically unstable in soft (hard) nonlinear potentials. PMID:27610856

  9. Two Approaches to Criterion-Referenced Program Assessment.

    ERIC Educational Resources Information Center

    Haladyna, Tom

    1982-01-01

    Describes two types of criterion-referenced testing that districts can use to measure achievement outcomes of their instructional programs: a random sampling assessment plan and an item-response theory assessment plan. (Author/JM)

  10. On the risk criterion and the index of risk

    SciTech Connect

    Wang, J.C.; Johnson, R.O.; Lee, D.W.

    1996-06-10

    The development of a means to quantify risk, the determination of a risk criterion, and the establishment of a method to compare risks are three essential components in a probabilistic safety assessment. In this paper, the quantitative definition of risk given by Kaplan and Garrick is converted from a table to a graph to accommodate Farmer`s method of constructing a risk criterion. Farmer`s criterion is limited to a straight line, but its slope is made a free parameter. The high-frequency small-consequence problem noted by Farmer is solved by using an auxiliary vertical line to exclude scenarios with insignificant consequences. To compare risks associated with various accident scenarios, an index of risk relative to the straight-line risk criterion is proposed and developed. The results allow various accident scenarios to be ranked according to their weighted risks and, in turn, provide a measure of the effectiveness of mitigation.

  11. An approximate spin design criterion for monoplanes, 1 May 1939

    NASA Technical Reports Server (NTRS)

    Seidman, O.; Donlan, C. J.

    1976-01-01

    An approximate empirical criterion, based on the projected side area and the mass distribution of the airplane, was formulated. The British results were analyzed and applied to American designs. A simpler design criterion, based solely on the type and the dimensions of the tail, was developed; it is useful in a rapid estimation of whether a new design is likely to comply with the minimum requirements for safety in spinning.

  12. GRAVITATIONAL FRAGMENTATION IN GALAXY MERGERS: A STABILITY CRITERION

    SciTech Connect

    Escala, Andres; Becerra, Fernando; Del Valle, Luciano; Castillo, Esteban

    2013-01-20

    We study the gravitational stability of gaseous streams in the complex environment of a galaxy merger, because mergers are known to be places of ongoing massive cluster formation and bursts of star formation. We find an analytic stability parameter for the case of gaseous streams orbiting around the merger remnant. We test our stability criterion using hydrodynamic simulations of galaxy mergers and obtain satisfactory results. We find that our criterion successfully predicts the streams that will be gravitationally unstable to fragmentation into clumps.

  13. A multiloop generalization of the circle stability criterion

    NASA Technical Reports Server (NTRS)

    Safonov, M. G.; Athans, M.

    1979-01-01

    A frequency-domain stability criterion is presented, generalizing the well-known circle stability criterion to multiloop feedback systems having bounded nonlinearity, parameter variations, and/or frequency-dependent ignorance of component dynamics. Unlike previous generalizations, the theory is not restricted to weakly-coupled, diagonally dominant or nearly normal systems. Potential applications include the analysis of feedback system integrity and multiloop feedback system stability margins.

  14. Criterion buys Akzo`s naphtha reforming catalysts business

    SciTech Connect

    Rotman, D.

    1993-12-08

    In a move that further consolidates the refinery catalysts market, Criterion Catalyst (Houston) has bought Akzo`s reforming business for an undisclosed price. The acquisition gives Criterion-a joint venture between Shell and American Cyanamid-roughly 35% of the $50-million/year worldwide reforming market. Akzo says it is quitting the business to focus on larger refinery catalysts applications in hydroprocessing and fluid cracking catalysts.

  15. VIOLATION OF RICHARDSON'S CRITERION VIA INTRODUCTION OF A MAGNETIC FIELD

    SciTech Connect

    Lecoanet, Daniel; Zweibel, Ellen G.; Townsend, Richard H. D.; Huang Yimin

    2010-04-01

    Shear flow instabilities can profoundly affect the diffusion of momentum in jets, stars, and disks. The Richardson criterion gives a sufficient condition for instability of a shear flow in a stratified medium. The velocity gradient V' can only destabilize a stably stratified medium with squared Brunt-Vaeisaelae frequency N {sup 2} if V'{sup 2}/4>N {sup 2}. We find this is no longer true when the medium is a magnetized plasma. We investigate the effect of stable stratification on the magnetic field and velocity profiles unstable to magneto-shear instabilities, i.e., instabilities which require the presence of both magnetic field and shear flow. We show that a family of profiles originally studied by Tatsuno and Dorland remains unstable even when V'{sup 2}/4 < N {sup 2}, violating the Richardson criterion. However, not all magnetic fields can result in a violation of the Richardson criterion. We consider a class of flows originally considered by Kent, which are destabilized by a constant magnetic field, and show that they become stable when V'{sup 2}/4 < N {sup 2}, as predicted by the Richardson criterion. This suggests that magnetic free energy is required to violate the Richardson criterion. This work implies that the Richardson criterion cannot be used when evaluating the ideal stability of a sheared, stably stratified, and magnetized plasma. We briefly discuss the implications for astrophysical systems.

  16. An improved failure criterion for biological and engineered staggered composites.

    PubMed

    Barthelat, Francois; Dastjerdi, Ahmad Khayer; Rabiei, Reza

    2013-02-01

    High-performance biological materials such as nacre, spider silk or bone have evolved a staggered microstructure consisting of stiff and strong elongated inclusions aligned with the direction of loading. This structure leads to useful combinations of stiffness, strength and toughness, and it is therefore increasingly mimicked in bio-inspired composites. The performance of staggered composites can be tuned; for example, their mechanical properties increase when the overlap between the inclusions is increased. However, larger overlaps may lead to excessive tensile stress and fracture of the inclusions themselves, a highly detrimental failure mode. Fracture of the inclusions has so far only been predicted using highly simplified models, which hinder our ability to properly design and optimize engineered staggered composites. In this work, we develop a new failure criterion that takes into account the complex stress field within the inclusions as well as initial defects. The model leads to an 'optimum criterion' for cases where the shear tractions on the inclusions is uniform, and a 'conservative' criterion for which the tractions are modelled as point forces at the ends of the overlap regions. The criterion can therefore be applied for a wide array of material behaviour at the interface, even if the details of the shear load transfer is not known. The new criterion is validated with experiments on staggered structures made of millimetre-thick alumina tablets, and by comparison with data on nacre. Formulated in a non-dimensional form, our new criterion can be applied on a wide variety of engineered staggered composites at any length scale. It also reveals new design guidelines, for example high aspect ratio inclusions with weak interfaces are preferable over inclusions with low aspect ratio and stronger interfaces. Together with existing models, this new criterion will lead to optimal designs that harness the full potential of bio-inspired staggered composites. PMID

  17. Dubious decision evidence and criterion flexibility in recognition memory

    PubMed Central

    Kantner, Justin; Vettel, Jean M.; Miller, Michael B.

    2015-01-01

    When old–new recognition judgments must be based on ambiguous memory evidence, a proper criterion for responding “old” can substantially improve accuracy, but participants are typically suboptimal in their placement of decision criteria. Various accounts of suboptimal criterion placement have been proposed. The most parsimonious, however, is that subjects simply over-rely on memory evidence – however faulty – as a basis for decisions. We tested this account with a novel recognition paradigm in which old–new discrimination was minimal and critical errors were avoided by adopting highly liberal or conservative biases. In Experiment 1, criterion shifts were necessary to adapt to changing target probabilities or, in a “security patrol” scenario, to avoid either letting dangerous people go free (misses) or harming innocent people (false alarms). Experiment 2 added a condition in which financial incentives drove criterion shifts. Critical errors were frequent, similar across sources of motivation, and only moderately reduced by feedback. In Experiment 3, critical errors were only modestly reduced in a version of the security patrol with no study phase. These findings indicate that participants use even transparently non-probative information as an alternative to heavy reliance on a decision rule, a strategy that precludes optimal criterion placement. PMID:26441706

  18. A new tracer-density criterion for heterogeneous porous media

    USGS Publications Warehouse

    Barth, G.R.; Illangasekare, T.H.; Hill, M.C.; Rajaram, H.

    2001-01-01

    Tracerexperiments provide information about aquifer material properties vital for accurate site characterization. Unfortunately, density-induced sinking can distort tracer movement, leading to an inaccurate assessment of material properties. Yet existing criteria for selecting appropriate tracer concentrations are based on analysis of homogeneous media instead of media with heterogeneities typical of field sites. This work introduces a hydraulic-gradient correction for heterogeneous media and applies it to a criterion previously used to indicate density-induced instabilities in homogeneous media. The modified criterion was tested using a series of two-dimensional heterogeneous intermediate-scale tracer experiments and data from several detailed field tracer tests. The intermediate-scale experimental facility (10.0 ?? 1.2 ?? 0.06 m) included both homogeneous and heterogeneous (??2/In ?? = 1.22) zones. The field tracer tests were less heterogeneous (0.24 < ??2/ln ?? < 0.37), but measurements were sufficient to detect density-induced sinking. Evaluation of the modified criterion using the experiments and field tests demonstrates that the new criterion appears to account for the change in density-induced sinking due to heterogeneity. The criterion demonstrates the importance of accounting for heterogeneity to predict density-induced sinking and differences in the onset of density induced sinking in two-and three-dimensional systems.

  19. A path-tracking criterion for an LHD articulated vehicle

    SciTech Connect

    Altafini, C.

    1999-05-01

    A path-tracking criterion for the so-called LHD (load-haul-dump) truck used in underground mining is proposed in this paper. It exploits the particular configuration of this vehicle, composed of two units connected by an actuated articulation. The task is to follow the path represented by the middle of the tunnel, maintaining the whole vehicle at a reduced distance from the path itself, to decrease the risk of crashes against the walls of the tunnel. This is accomplished via feedback through the synthesis of an appropriate path-tracking criterion. The criterion is based on monitoring the distances of the midpoints of both axles of the vehicle from their orthogonal projections on the path, using two different moving frames simultaneously. Local asymptotic stability to paths of constant curvature is achieved by means of linear-state feedback.

  20. UPRE-variant: a novel criterion for parametric PSF estimation

    NASA Astrophysics Data System (ADS)

    Xue, Feng; Li, Zhifeng; Liu, Jiaqi; Meng, Gang; Zhao, Min

    2015-10-01

    We propose a variant of unbiased predictive risk estimate (UPRE) as a novel criterion for estimating a point spread function (PSF) from the degraded image only. Compared to the traditional unbiased estimates (e.g. UPRE and SURE), the key advantage of this variant is that it does not require the knowledge of noise variance. The PSF is obtained by minimizing this new objective functional over a family of smoother processings. Based on this estimated PSF, we then perform deconvolution using our recently developed SURE-LET algorithm. The novel criterion is exemplified with a number of parametric PSF. The experimental results demonstrate that the UPRE-variant minimization yields highly accurate estimates of the PSF parameters, which also result in a negligible loss of visual quality, compared to that obtained with the exact PSF. The highly competitive results outline the great potential of developing more powerful blind deconvolution algorithms based on this criterion.

  1. A New Biomechanically-Based Criterion for Lateral Skull Fracture

    PubMed Central

    Vorst, Michael Vander; Chan, Philemon; Zhang, Jiangyue; Yoganandan, Narayan; Pintar, Frank

    2004-01-01

    This work develops a skull fracture criterion for lateral impact-induced head injury using postmortem human subject tests, anatomical test device measurements, statistical analyses, and finite element modeling. It is shown that skull fracture correlates with the tensile strain in the compact tables of the cranial bone as calculated by the finite element model and that the Skull Fracture Correlate (SFC), the average acceleration over the HIC time interval, is the best predictor of skull fracture. For 15% or less probability of skull fracture the lateral skull fracture criterion is SFC < 120 g, which is the same as the frontal criterion derived earlier. The biomechanical basis of SFC is established by its correlation with strain. PMID:15319125

  2. The role of word choice and criterion on intentional memory.

    PubMed

    Toyota, Hiroshi

    2015-02-01

    The relationship between the criterion for choosing and the self-choice effects (greater recall in a self-choice compared to a forced-choice condition) on intentional memory was examined. Thirty-three female nursing school volunteers were administered 24 word pairs in a 2 × 2 design to assess the influence of motivation upon free recall. When word pairs were presented to participants, they were asked to choose a word to-be-remembered, either in a self-choice condition or a forced-choice condition. Words chosen by the participants were recalled more often than those chosen by the experimenter (forced choice). Thus, the self-choice effect was greater for words chosen with a self-reference criterion compared to a metamemory criterion, supporting the integration hypothesis as the origin of the self-choice effect. PMID:25621524

  3. Robust Criterion for the Existence of Nonhyperbolic Ergodic Measures

    NASA Astrophysics Data System (ADS)

    Bochi, Jairo; Bonatti, Christian; Díaz, Lorenzo J.

    2016-06-01

    We give explicit C 1-open conditions that ensure that a diffeomorphism possesses a nonhyperbolic ergodic measure with positive entropy. Actually, our criterion provides the existence of a partially hyperbolic compact set with one-dimensional center and positive topological entropy on which the center Lyapunov exponent vanishes uniformly. The conditions of the criterion are met on a C 1-dense and open subset of the set of diffeomorphisms having a robust cycle. As a corollary, there exists a C 1-open and dense subset of the set of non-Anosov robustly transitive diffeomorphisms consisting of systems with nonhyperbolic ergodic measures with positive entropy. The criterion is based on a notion of a blender defined dynamically in terms of strict invariance of a family of discs.

  4. Criticality and quenched disorder: Harris criterion versus rare regions.

    PubMed

    Vojta, Thomas; Hoyos, José A

    2014-02-21

    We employ scaling arguments and optimal fluctuation theory to establish a general relation between quantum Griffiths singularities and the Harris criterion for quantum phase transitions in disordered systems. If a clean critical point violates the Harris criterion, it is destabilized by weak disorder. At the same time, the Griffiths dynamical exponent z' diverges upon approaching the transition, suggesting unconventional critical behavior. In contrast, if the Harris criterion is fulfilled, power-law Griffiths singularities can coexist with clean critical behavior, but z' saturates at a finite value. We present applications of our theory to a variety of systems including quantum spin chains, classical reaction-diffusion systems and metallic magnets, and we discuss modifications for transitions above the upper critical dimension. Based on these results we propose a unified classification of phase transitions in disordered systems. PMID:24579616

  5. Bohm's criterion in a collisional magnetized plasma with thermal ions

    SciTech Connect

    Hatami, M. M.; Shokri, B.

    2012-08-15

    Using the hydrodynamic model and considering a planar geometry, the modified Bohm's sheath criterion is investigated in a magnetized, collisional plasma consisting of electron and positive ions with finite temperature. It is assumed that the singly charged positive ions enter into the sheath region obliquely, i.e., their velocity at the sheath edge is not normal to the wall, and the electron densities obey Boltzmann relations. It is shown that there are both upper and lower limit for the Bohm entrance velocity of ions in this case and both of these limits depend on the magnitude and direction of the applied magnetic field. To determine the accuracy of our derived generalized Bohm's criterion, it reduced to some familiar physical condition. Also, using this generalized Bohm's criterion, the behavior of the electron and positive ion density distributions are studied in the sheath region.

  6. An improved failure criterion for biological and engineered staggered composites

    PubMed Central

    Barthelat, Francois; Dastjerdi, Ahmad Khayer; Rabiei, Reza

    2013-01-01

    High-performance biological materials such as nacre, spider silk or bone have evolved a staggered microstructure consisting of stiff and strong elongated inclusions aligned with the direction of loading. This structure leads to useful combinations of stiffness, strength and toughness, and it is therefore increasingly mimicked in bio-inspired composites. The performance of staggered composites can be tuned; for example, their mechanical properties increase when the overlap between the inclusions is increased. However, larger overlaps may lead to excessive tensile stress and fracture of the inclusions themselves, a highly detrimental failure mode. Fracture of the inclusions has so far only been predicted using highly simplified models, which hinder our ability to properly design and optimize engineered staggered composites. In this work, we develop a new failure criterion that takes into account the complex stress field within the inclusions as well as initial defects. The model leads to an ‘optimum criterion’ for cases where the shear tractions on the inclusions is uniform, and a ‘conservative’ criterion for which the tractions are modelled as point forces at the ends of the overlap regions. The criterion can therefore be applied for a wide array of material behaviour at the interface, even if the details of the shear load transfer is not known. The new criterion is validated with experiments on staggered structures made of millimetre-thick alumina tablets, and by comparison with data on nacre. Formulated in a non-dimensional form, our new criterion can be applied on a wide variety of engineered staggered composites at any length scale. It also reveals new design guidelines, for example high aspect ratio inclusions with weak interfaces are preferable over inclusions with low aspect ratio and stronger interfaces. Together with existing models, this new criterion will lead to optimal designs that harness the full potential of bio-inspired staggered composites

  7. PTSD and Sexual Orientation: An Examination of Criterion A1 and Non-Criterion A1 Events

    PubMed Central

    Alessi, Edward J.; Meyer, Ilan H.; Martin, James I.

    2015-01-01

    This large-scale cross-sectional study compared posttraumatic stress disorder (PTSD) prevalence among White, Black, and Latino lesbian, gay and bisexual individuals (LGBs; n = 382) and compared them with heterosexual individuals (n = 126). Building on previous research, we relaxed the criteria of the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM–IV; American Psychiatric Association, 1994), allowing non-Criterion A1 events such as ending a relationship, unemployment, homelessness, and separation from parents to qualify, and we assessed differences in PTSD prevalence between standard DSM–IV criteria and the relaxed criteria. Findings revealed that participants reporting a non-Criterion A1 event were more likely than those reporting a Criterion A1 event to have symptoms diagnosable as PTSD. There was no significant difference in either DSM–IV or relaxed Criterion A1 PTSD prevalence between lesbian and gay, and heterosexual individuals or between bisexual and heterosexual individuals. Compared with White LGBs, Black and Latino LGBs had higher prevalence of PTSD with the relaxed Criterion A1 definition, but this was statistically significant only for Latinos. PMID:26113955

  8. Automatic control systems satisfying certain general criterions on transient behavior

    NASA Technical Reports Server (NTRS)

    Boksenbom, Aaron S; Hood, Richard

    1952-01-01

    An analytic method for the design of automatic controls is developed that starts from certain arbitrary criterions on the behavior of the controlled system and gives those physically realizable equations that the control system can follow in order to realize this behavior. The criterions used are developed in the form of certain time integrals. General results are shown for systems of second order and of any number of degrees of freedom. Detailed examples for several cases in the control of a turbojet engine are presented.

  9. Nonequilibrium Gibbs' criterion for completely wetting volatile liquids.

    PubMed

    Tsoumpas, Yannis; Dehaeck, Sam; Galvagno, Mariano; Rednikov, Alexey; Ottevaere, Heidi; Thiele, Uwe; Colinet, Pierre

    2014-10-14

    During the spreading of a liquid over a solid substrate, the contact line can stay pinned at sharp edges until the contact angle exceeds a critical value. At (or sufficiently near) equilibrium, this is known as Gibbs' criterion. Here, we show both experimentally and theoretically that, for completely wetting volatile liquids, there also exists a dynamically-produced contribution to the critical angle for depinning, which increases with the evaporation rate. This suggests that one may introduce a simple modification of the Gibbs' criterion for (de)pinning that accounts for the nonequilibrium effect of evaporation. PMID:25222133

  10. An Elementary Proof of a Criterion for Linear Disjointness

    ERIC Educational Resources Information Center

    Dobbs, David E.

    2013-01-01

    An elementary proof using matrix theory is given for the following criterion: if "F"/"K" and "L"/"K" are field extensions, with "F" and "L" both contained in a common extension field, then "F" and "L" are linearly disjoint over "K" if (and only if) some…

  11. Procedures for Empirical Determination of En-Route Criterion Levels.

    ERIC Educational Resources Information Center

    Moncrief, Michael H.

    En-route Criterion Levels (ECLs) are defined as decision rules for predicting pupil readiness to advance through an instructional sequence. This study investigated the validity of present ELCs in an individualized mathematics program and tested procedures for empirically determining optimal ECLs. Retest scores and subsequent progress were…

  12. Validity criterion for the Born approximation convergence in microscopy imaging.

    PubMed

    Trattner, Sigal; Feigin, Micha; Greenspan, Hayit; Sochen, Nir

    2009-05-01

    The need for the reconstruction and quantification of visualized objects from light microscopy images requires an image formation model that adequately describes the interaction of light waves with biological matter. Differential interference contrast (DIC) microscopy, as well as light microscopy, uses the common model of the scalar Helmholtz equation. Its solution is frequently expressed via the Born approximation. A theoretical bound is known that limits the validity of such an approximation to very small objects. We present an analytic criterion for the validity region of the Born approximation. In contrast to the theoretical known bound, the suggested criterion considers the field at the lens, external to the object, that corresponds to microscopic imaging and extends the validity region of the approximation. An analytical proof of convergence is presented to support the derived criterion. The suggested criterion for the Born approximation validity region is described in the context of a DIC microscope, yet it is relevant for any light microscope with similar fundamental apparatus. PMID:19412231

  13. Criterion-Referenced Test Items for Small Engines.

    ERIC Educational Resources Information Center

    Herd, Amon

    This notebook contains criterion-referenced test items for testing students' knowledge of small engines. The test items are based upon competencies found in the Missouri Small Engine Competency Profile. The test item bank is organized in 18 sections that cover the following duties: shop procedures; tools and equipment; fasteners; servicing fuel…

  14. Personal Career Orientation. Performance Objectives. Criterion Measures. Home Economics.

    ERIC Educational Resources Information Center

    Allen, Alveta; And Others

    Several intermediate performance objectives and corresponding criterion measures are listed for each of six terminal objectives for a personal career orientation course for seventh grade students. This 6- to 9-week course is designed to acquaint the student with personal qualities and characteristics necessary for success in the world of work.…

  15. Signal Detection with Criterion Noise: Applications to Recognition Memory

    ERIC Educational Resources Information Center

    Benjamin, Aaron S.; Diaz, Michael; Wee, Serena

    2009-01-01

    A tacit but fundamental assumption of the theory of signal detection is that criterion placement is a noise-free process. This article challenges that assumption on theoretical and empirical grounds and presents the noisy decision theory of signal detection (ND-TSD). Generalized equations for the isosensitivity function and for measures of…

  16. A Criterion-Referenced Examination of Physician Competence.

    ERIC Educational Resources Information Center

    Norcini, John J.; And Others

    1988-01-01

    A test of skill in reading electrocardiographs (ECGs) was developed as a physician competence (PC) test. The criterion-referenced test ranked 1,825 persons taking the 1983 Certifying Examination in Cardiovascular Diseases (CECD) as expected on the basis of prior education and examination scores on the CECD. The ECG test modestly correlated with…

  17. Verbalizing Facial Memory: Criterion Effects in Verbal Overshadowing

    ERIC Educational Resources Information Center

    Clare, Joseph; Lewandowsky, Stephan

    2004-01-01

    This article investigated the role of the recognition criterion in the verbal overshadowing effect (VOE). In 3 experiments, people witnessed an event, verbally described a perpetrator, and then attempted identification. The authors found in Experiment 1, which included a "not present" response option and both perpetrator-present (PP) and…

  18. Criterion-Referenced Test (CRT) Items for Building Trades.

    ERIC Educational Resources Information Center

    Davis, Diane, Ed.

    This test item bank is intended to help instructors construct criterion-referenced tests for secondary-level courses in building trades. The bank is keyed to the Missouri Building Trades Competency Profile, which was developed by industry and education professionals in Missouri, and is designed to be used in conjunction with the Vocational…

  19. The Oral Interview - A Criterion-Referenced Test?

    ERIC Educational Resources Information Center

    Lowe, Pardee, Jr.

    The oral interview may be viewed as a criterion-referenced test for making either/or decisions about functional use of spoken language. Speech production can be tested by either the oral interview or the Valdis (1972) "Performance Objectives for Speaking," and dialogue between the two systems can be profitable. Current literature on…

  20. Application of Weibull Criterion to failure prediction in compsites

    SciTech Connect

    Cain, W. D.; Knight, Jr., C. E.

    1981-04-20

    Fiber-reinforced composite materials are being widely used in engineered structures. This report examines how the general form of the Weibull Criterion, including the evaluation of the parameters and the scaling of the parameter values, can be used for the prediction of component failure.

  1. Criterion-Referenced Test Items for Vocational Education. Final Report.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Instructional Materials Lab.

    A project was conducted to develop and validate criterion-referenced test items for the following vocational education programs: child care worker, machine shop, electronics, drafting, and automobile mechanics. For each of the programs, the following activities took place: a project coordinator was assigned, subject-area instructors and a test…

  2. The Criterion Validity of Tasks of Basic Cognitive Processes

    ERIC Educational Resources Information Center

    Luo, Dasen; Thompson, Lee A.; Detterman, Douglas K.

    2006-01-01

    The present study evaluated the criterion validity of the aggregated tasks of basic cognitive processes (TBCP). In age groups from 6 to 19 of the Woodcock-Johnson III Cognitive Abilities and Achievement Tests normative sample, the aggregated TBCP, i.e., the processing speed and working memory clusters, correlate with measures of scholastic…

  3. An adhesion criterion in the gas solid interface

    NASA Technical Reports Server (NTRS)

    George, M. C.

    1973-01-01

    A theoretical model is developed to establish an adhesion criterion for the interaction of a gas atom or molecule with a nonmetallic surface. As a first approximation a linear lattice mass points of the solid surface is considered and the classical lattice dynamical model is used.

  4. Service Orientation as a Selection Criterion for Public Services Librarians.

    ERIC Educational Resources Information Center

    Allen, Gillian; Allen, Bryce

    1992-01-01

    This study examined the use of service orientation as a selection criterion for public services librarians in public and academic libraries. Analysis of job advertisements and data collected by questionnaires sent to a sample of individuals responsible for hiring public services librarians indicated the importance of service orientation. (three…

  5. Criterion-Referenced Test Items for Auto Body.

    ERIC Educational Resources Information Center

    Tannehill, Dana, Ed.

    This test item bank on auto body repair contains criterion-referenced test questions based upon competencies found in the Missouri Auto Body Competency Profile. Some test items are keyed for multiple competencies. The tests cover the following 26 competency areas in the auto body curriculum: auto body careers; measuring and mixing; tools and…

  6. Child Care Services Guide. Performance Objectives. Criterion Measures. Home Economics.

    ERIC Educational Resources Information Center

    Duval County School Board, Jacksonville, FL.

    Several intermediate performance objectives and corresponding criterion measures are listed for each of 14 terminal objectives for a high school child care services course. This course is designed to provide opportunities for exploring a broad range of child care, guidance, and service occupations. Major concepts include characteristics of…

  7. Machine Shop. Criterion-Referenced Test (CRT) Item Bank.

    ERIC Educational Resources Information Center

    Davis, Diane, Ed.

    This drafting criterion-referenced test item bank is keyed to the machine shop competency profile developed by industry and education professionals in Missouri. The 16 references used for drafting the test items are listed. Test items are arranged under these categories: orientation to machine shop; performing mathematical calculations; performing…

  8. A criterion for joint optimization of identification and robust control

    NASA Technical Reports Server (NTRS)

    Bayard, D. S.; Yam, Y.; Mettler, E.

    1992-01-01

    A criterion for system identification is developed that is consistent with the intended used of the fitted model for modern robust control synthesis. Specifically, a joint optimization problem is posed which simultaneously solves the plant model estimate and control design, so as to optimize robust performance over the set of plants consistent with a specified experimental data set.

  9. Some Reliability Problems in a Criterion-Referenced Test.

    ERIC Educational Resources Information Center

    Roudabush, Glenn E.; Green, Donald Ross

    This paper describes the development of a criterion-referenced test. The Prescriptive Mathematics Inventory (PMI) was developed to measure 400 stated behavioral objectives. The test consists of three overlapping levels with the objectives chosen to cover 90 to 95 per cent of the mathematics curriculum nominally taught in grades 4 through 8. Each…

  10. Auto Mechanics. Criterion-Referenced Test (CRT) Item Bank.

    ERIC Educational Resources Information Center

    Tannehill, Dana, Ed.

    This document contains 546 criterion-referenced multiple choice and true or false test items for a course in auto mechanics. The test item bank is designed to work with both the Vocational Instructional Management System (VIMS) and Vocational Administrative Management System (VAMS) in Missouri. The items are grouped into 35 units covering the…

  11. Prestimulus alpha power influences response criterion in a detection task.

    PubMed

    Limbach, Katharina; Corballis, Paul M

    2016-08-01

    Recent studies have linked variability in near-threshold stimulus detection to fluctuations in the prestimulus EEG alpha power (α, ∼8-12 Hz). Typically, these studies rely on hit rate as a measure of detection performance and show that detection is enhanced when α power is low compared to when it is high. However, hit rates are determined by both sensitivity to the stimulus and the placement of the response criterion. Here, we investigated the relationships between prestimulus α power and variability in these two measures on a single-trial basis. We confirm earlier reports that detection is inversely related to power in the individual α-frequency band. However, our results show a stronger relationship between α power and response criterion than with sensitivity. Higher α power was related to a more conservative response criterion (i.e., more "no" responses). A response criterion that varies depending on α power might help to optimize performance in an excited state and protect against false positives in a relatively disengaged state. PMID:27144476

  12. An Item Content Criterion of Debiasing a Test.

    ERIC Educational Resources Information Center

    Gonzalez-Tamayo, Eulogio

    An item content criterion, independent of the test psychometric characteristics, of classifying items as biased is described. It was used with a sample of female adults in a training program for administrative secretaries. The minority group in the study were Hispanic immigrants. The majority group was a mixture of Blacks, English speaking…

  13. The Calibration of a Criterion-Referenced Test.

    ERIC Educational Resources Information Center

    Kifer, Edward; Bramble, William

    A latent trait model, the Rasch, was fitted to a criterion-referenced test. Approximately 90 percent of the items fit the model. Those items which fit the model were then calibrated. Based on the item calibration, individual ability estimates and the standard errors of those estimates were calculated. Using the ability estimates, it was possible,…

  14. Criterion-Referenced Test Items for Graphic Arts.

    ERIC Educational Resources Information Center

    Davis, Diane, Ed.

    This test item bank on graphic arts contains test questions based upon competencies found in the Missouri Offset Lithography Competency Profile. Some test items are keyed for multiple competencies. These criterion-referenced test items are designed to work with the Vocational Instructional Management System. The tests cover the following 15…

  15. Electronics. Criterion-Referenced Test (CRT) Item Bank.

    ERIC Educational Resources Information Center

    Davis, Diane, Ed.

    This document contains 519 criterion-referenced multiple choice and true or false test items for a course in electronics. The test item bank is designed to work with both the Vocational Instructional Management System (VIMS) and the Vocational Administrative Management System (VAMS) in Missouri. The items are grouped into 15 units covering the…

  16. Food Production and Services. Performance Objectives. Criterion Measures. Home Economics.

    ERIC Educational Resources Information Center

    Bryant, EuDell H.; And Others

    Several intermediate performance objectives and corresponding criterion measures are listed for each of eight terminal objectives for a food production and services course, which is designed to provide students with an opportunity to express and practice a broad range of food production and service occupations. Major concepts covered include…

  17. Creativity.4in1: Four-Criterion Construct of Creativity

    ERIC Educational Resources Information Center

    Kharkhurin, Anatoliy V.

    2014-01-01

    The purpose of this theoretical article is to provide an extended definition of creativity that embraces potential cross-cultural variations in this construct. Creativity is defined as a 4-criterion construct, which includes attributes of novelty, utility, aesthetics, and authenticity. Novelty attribute stipulates that a creative work brings…

  18. Drafting. Criterion-Referenced Test (CRT) Item Bank.

    ERIC Educational Resources Information Center

    Mathew, Mary, Ed.

    This drafting criterion-referenced test item bank is keyed to the drafting competency profile developed by industry and education professionals in Missouri. The 12 references used for drafting the test items are listed. Test items are arranged under these categories: drafting room procedures; tools and equipment; basic drawing skills; geometric…

  19. The generalized partial transposition criterion for separability of multipartite quantum states

    NASA Astrophysics Data System (ADS)

    Chen, Kai; Wu, Ling-An

    2002-12-01

    We present a generalized partial transposition separability criterion for the density matrix of a multipartite quantum system. This criterion comprises as special cases the famous Peres-Horodecki criterion and the recent realignment criterion in [O. Rudolph, quant-ph/0202121] and [K. Chen, L.A. Wu, quant-ph/0205017]. It involves only straightforward matrix manipulations and is easy to apply. A quantitative measure of entanglement based on this criterion is also obtained.

  20. Some properties of the computable cross-norm criterion for separability

    SciTech Connect

    Rudolph, Oliver

    2003-03-01

    The computable cross-norm (CCN) criterion is a powerful analytical and computable separability criterion for bipartite quantum states, which is also known to systematically detect bound entanglement. In certain aspects this criterion complements the well-known Peres positive partial transpose (PPT) criterion. In the present paper we study important analytical properties of the CCN criterion. We show that in contrast to the PPT criterion it is not sufficient in dimension 2x2. In higher dimensions, theorems connecting the fidelity of a quantum state with the CCN criterion are proved. We also analyze the behavior of the CCN criterion under local operations and identify the operations that leave it invariant. It turns out that the CCN criterion is in general not invariant under local operations.

  1. A New Improved Failure Criterion for Salt Rock Based on Energy Method

    NASA Astrophysics Data System (ADS)

    Hao, T. S.; Liang, W. G.

    2016-05-01

    A non-linear triple shear energy yield criterion for salt rock is presented in this paper. It is the development of the triple shear energy yield criterion, of which the Mohr-Coulomb criterion can be seen as a special case. The main factors affecting the primary strength of salt rock, such as the mean stress and the Lode angle, are considered in the non-linear triple shear energy yield criterion. The non-linear new criterion provides the non-linear change trend of salt strength both in the I 1- J 2 stress space and in the deviatoric plane. Comparative study between the non-linear criterion predictions and experimental results of salt rock shows that the non-linear triple shear energy yield criterion fits quite well with both conventional triaxial test data and the true triaxial test data. For Maha Sarakham salt, the predictive capability of the non-linear triple shear energy yield criterion is clearly better than that of some other criteria used by Sriapai, such as modified Lade criterion, 3-D Hoek, and Brown criterion, Drucker-Prager criterion et al. The availability of the non-linear triple shear energy yield criterion can also be confirmed by comparative analysis between theoretical values and experimental values for non-salt rocks. So the non-linear triple shear energy yield criterion is a general failure criterion for rocks fractured by shear stress.

  2. On thermonuclear ignition criterion at the National Ignition Facility

    SciTech Connect

    Cheng, Baolian; Kwan, Thomas J. T.; Wang, Yi-Ming; Batha, Steven H.

    2014-10-15

    Sustained thermonuclear fusion at the National Ignition Facility remains elusive. Although recent experiments approached or exceeded the anticipated ignition thresholds, the nuclear performance of the laser-driven capsules was well below predictions in terms of energy and neutron production. Such discrepancies between expectations and reality motivate a reassessment of the physics of ignition. We have developed a predictive analytical model from fundamental physics principles. Based on the model, we obtained a general thermonuclear ignition criterion in terms of the areal density and temperature of the hot fuel. This newly derived ignition threshold and its alternative forms explicitly show the minimum requirements of the hot fuel pressure, mass, areal density, and burn fraction for achieving ignition. Comparison of our criterion with existing theories, simulations, and the experimental data shows that our ignition threshold is more stringent than those in the existing literature and that our results are consistent with the experiments.

  3. Fermion-induced quantum critical points: beyond Landau criterion

    NASA Astrophysics Data System (ADS)

    Yao, Hong; Li, Zi-Xiang; Jiang, Yi-Fan; Jian, Shao-Kai

    According to Landau criterion, phase transitions must be first-order when cubic terms of order parameters in the Landau-Ginzburg free energy are allowed by symmetry. Here, from both renormalization group analysis and sign-problem-free quantum Monte Carlo simulations, we show that second-order quantum phase transitions can occur at such putatively-first-order quantum phase transitions in strongly-interacting Dirac semimetals in two spatial dimensions. Such type of Landau-criterion-violating quantum critical points are induced by massless fermionic modes at the quantum phase transitions. We call them ``fermion-induced quantum critical points''. From Majorana-quantum-Monte-Carlo simulations and renormalization analysis, we find that the critical exponentials at the kekule valence-bond-solid transition of the Dirac fermions on the honeycomb lattice are highly-nonclassical. We also discuss experimental signatures of the kekule quantum critical point which may be realized in graphene-like systems.

  4. Criterion-related validity of the Arabic Children's Depression Inventory.

    PubMed

    Abdel-Khalek, A M

    1998-06-01

    The Arabic Children's Depression Inventory and the Beck Depression Inventory were administered to 109 Kuwaiti school students whose ages ranged from 14 to 18 years. Pearson correlations for total score on the two scales were .57, .83, and .75 for boys, girls, and the combined group, respectively, denoting the convergent validity of the new Arabic inventory against the Beck Depression Inventory as criterion. PMID:9676502

  5. Criterion validity of manual assessment of spinal stiffness.

    PubMed

    Koppenhaver, Shane L; Hebert, Jeffrey J; Kawchuk, Greg N; Childs, John D; Teyhen, Deydre S; Croy, Theodore; Fritz, Julie M

    2014-12-01

    Assessment of spinal stiffness is widely used by manual therapy practitioners as a part of clinical diagnosis and treatment selection. Although studies have commonly found poor reliability of such procedures, conflicting evidence suggests that assessment of spinal stiffness may help predict response to specific treatments. The current study evaluated the criterion validity of manual assessments of spinal stiffness by comparing them to indentation measurements in patients with low back pain (LBP). As part of a standard examination, an experienced clinician assessed passive accessory spinal stiffness of the L3 vertebrae using posterior to anterior (PA) force on the spinous process of L3 in 50 subjects (54% female, mean (SD) age = 33.0 (12.8) years, BMI = 27.0 (6.0) kg/m(2)) with LBP. A criterion measure of spinal stiffness was performed using mechanized indentation by a blinded second examiner. Results indicated that manual assessments were uncorrelated to criterion measures of stiffness (spearman rho = 0.06, p = 0.67). Similarly, sensitivity and specificity estimates of judgments of hypomobility were low (0.20-0.45) and likelihood ratios were generally not statistically significant. Sensitivity and specificity of judgments of hypermobility were not calculated due to limited prevalence. Additional analysis found that BMI explained 32% of the variance in the criterion measure of stiffness, yet failed to improve the relationship between assessments. Additional studies should investigate whether manual assessment of stiffness relates to other clinical and biomechanical constructs, such as symptom reproduction, angular rotation, quality of motion, or end feel. PMID:24965495

  6. A selection criterion for patterns in reaction–diffusion systems

    PubMed Central

    2014-01-01

    Background Alan Turing’s work in Morphogenesis has received wide attention during the past 60 years. The central idea behind his theory is that two chemically interacting diffusible substances are able to generate stable spatial patterns, provided certain conditions are met. Ever since, extensive work on several kinds of pattern-generating reaction diffusion systems has been done. Nevertheless, prediction of specific patterns is far from being straightforward, and a great deal of interest in deciphering how to generate specific patterns under controlled conditions prevails. Results Techniques allowing one to predict what kind of spatial structure will emerge from reaction–diffusion systems remain unknown. In response to this need, we consider a generalized reaction diffusion system on a planar domain and provide an analytic criterion to determine whether spots or stripes will be formed. Our criterion is motivated by the existence of an associated energy function that allows bringing in the intuition provided by phase transitions phenomena. Conclusions Our criterion is proved rigorously in some situations, generalizing well-known results for the scalar equation where the pattern selection process can be understood in terms of a potential. In more complex settings it is investigated numerically. Our work constitutes a first step towards rigorous pattern prediction in arbitrary geometries/conditions. Advances in this direction are highly applicable to the efficient design of Biotechnology and Developmental Biology experiments, as well as in simplifying the analysis of morphogenetic models. PMID:24476200

  7. Criterion validation of a stress measure: the Stress Overload Scale.

    PubMed

    Amirkhan, James H; Urizar, Guido G; Clark, Sarah

    2015-09-01

    Validating stress scales poses problems beyond those of other psychological measures. Here, 3 studies were conducted to address those problems and assess the criterion validity of scores from a new theory-derived measure, the Stress Overload Scale (SOS; Amirkhan, 2012). In Study 1, the SOS was tested for its ability to predict postsemester illness in a sample of college students (n = 127). Even with precautions to minimize criterion contamination, scores were found to predict health problems in the month following a final exam on all of 5 different criteria. In Study 2, a community sample (n = 231) was used to test the SOS' ability to differentiate people in stressful circumstances from those in more relaxed contexts. SOS scores demonstrated excellent sensitivity (96%) and specificity (100%) in this general population application. In Study 3, the SOS was tested for its ability to differentiate salivary cortisol responses to a laboratory stressor in a group of pregnant women (n = 40). High scores were found to be associated with a blunted cortisol response, which is indicative of HPA-axis overload and typical of persons suffering chronic stress and stress-related pathology. Across all 3 studies, despite variations in the stressor, criterion, population, and methods, SOS scores emerged as valid indicators of stress. However, each study also introduced new problems that beg additional corrective steps in future stress-scale validity tests. These strategies, and the SOS' utility as a research and diagnostic tool in varied applications and populations, are discussed. PMID:25642927

  8. Signal detection with criterion noise: Applications to recognition memory

    PubMed Central

    Benjamin, Aaron S.; Diaz, Michael; Wee, Serena

    2010-01-01

    A tacit but fundamental assumption of the Theory of Signal Detection (TSD) is that criterion placement is a noise-free process. This paper challenges that assumption on theoretical and empirical grounds and presents the Noisy Decision Theory of Signal Detection (ND-TSD). Generalized equations for the isosensitivity function and for measures of discrimination that incorporate criterion variability are derived, and the model's relationship with extant models of decision-making in discrimination tasks is examined. An experiment that evaluates recognition memory for ensembles of word stimuli reveals that criterion noise is not trivial in magnitude and contributes substantially to variance in the slope of the isosensitivity function. We discuss how ND-TSD can help explain a number of current and historical puzzles in recognition memory, including the inconsistent relationship between manipulations of learning and the slope of the isosensitivity function, the lack of invariance of the slope with manipulations of bias or payoffs, the effects of aging on the decision-making process in recognition, and the nature of responding in Remember/Know decision tasks. ND-TSD poses novel and theoretically meaningful constraints on theories of recognition and decision-making more generally, and provides a mechanism for rapprochement between theories of decision-making that employ deterministic response rules and those that postulate probabilistic response rules. PMID:19159149

  9. On the upper bound in the Bohm sheath criterion

    NASA Astrophysics Data System (ADS)

    Kotelnikov, I. A.; Skovorodin, D. I.

    2016-02-01

    The question is discussed about the existence of an upper bound in the Bohm sheath criterion, according to which the Debye sheath at the interface between plasma and a negatively charged electrode is stable only if the ion flow velocity in plasma exceeds the ion sound velocity. It is stated that, with an exception of some artificial ionization models, the Bohm sheath criterion is satisfied as an equality at the lower bound and the ion flow velocity is equal to the speed of sound. In the one-dimensional theory, a supersonic flow appears in an unrealistic model of a localized ion source the size of which is less than the Debye length; however, supersonic flows seem to be possible in the two- and three-dimensional cases. In the available numerical codes used to simulate charged particle sources with a plasma emitter, the presence of the upper bound in the Bohm sheath criterion is not supposed; however, the correspondence with experimental data is usually achieved if the ion flow velocity in plasma is close to the ion sound velocity.

  10. The entropy rate admissibility criterion for solution of hyperbolic conservation laws

    NASA Technical Reports Server (NTRS)

    Dafermos, C. M.

    1972-01-01

    The entropy rate admissibility criterion for solutions of hyperbolic conservation laws is numerically analyzed. The following admissibility criterion for solutions of hyperbolic conservation laws is proposed: a weak solution is admissible if the total entropy decays with the highest possible rate. The equivalence of this criterion and viscosity criterion is established for the single equation and the system of equations of one dimensional nonlinear elasticity.

  11. ABET Criterion 3.f: how much curriculum content is enough?

    PubMed

    Barry, B E; Ohland, M W

    2012-06-01

    Even after multiple cycles of ABET accreditation, many engineering programs are unsure of how much curriculum content is needed to meet the requirements of ABET's Criterion 3.f (an understanding of professional and ethical responsibility). This study represents the first scholarly attempt to assess the impact of curriculum reform following the introduction of ABET Criterion 3.f. This study sought to determine how much professional and ethical responsibility curriculum content was used between 1995 and 2005, as well as how, when, why, and to what effect changes in the amount of content occurred. Subsequently, the study sought to evaluate if different amounts of curriculum content generated differing student outcomes. The amount of curriculum content used by each of the participating programs was identified during semi-structured interviews with program administrators and a review of ABET Self-Study documents. Quantitative methods were applied to determine if a relationship existed between the curriculum content and performance on a nationally administered, engineering-specific standardized examination. The findings indicate a statistical relationship, but a lack of structure between the amount of required content in the curriculum and performance on the examination. Additional findings were also generated regarding the way that programs interpret the Criterion 3.f feedback generated during accreditation visits. The primary impact of this study is that it dispels the myth that more courses or course time on professionalism and ethics will necessarily lead to positive engineering education outcomes. Much of the impetus to add more curriculum content results from a lack of conclusive feedback during ABET accreditation visits. PMID:21318324

  12. On the sampling criterion for structural radiation in fluid.

    PubMed

    Veronesi, Giorgio; Nijman, Eugène J M

    2016-05-01

    When experimentally investigating the sound radiating from vibrating structures the surface is discretised into elemental areas also referred to as patches in which the surface vibrations are considered uniform. In many cases the structural Nyquist criterion imposes very small patch sizes which turn the experimental analysis into an overwhelmingly elaborate and error-prone task. The possibility to use a coarse sampling scheme for the surface velocity can greatly enhance the practical feasibility of such experimental investigations. Here the special case of a simply supported baffled plate excited by a broadband point force is considered. It is shown that accurate approximations of the radiated power may be obtained well beyond the frequency limit imposed by the structural Nyquist sampling criterion, provided the complex-valued vibration field is averaged over each patch. This is due to the fact that the structural wave components with wavenumbers greater than the acoustic wavenumber tend to be averaged out, owing to the mutual canceling of areas which vibrate out-of-phase within each patch, leaving only those components that contribute significantly to the radiated sound. It turns out, however, that this canceling process is not complete and that an error is introduced by the spatial aliasing. An analytical expression is derived allowing one to quantify this error and to optimise the patch size given a desired accuracy level and frequency range for the assessment of the radiated power. The proposed sampling criterion not only allows one to significantly reduce the measurement efforts when the radiation of vibro-acoustic systems are experimentally investigated but can also be applied to reduce the size of numerical models for weakly coupled structural-acoustic systems. PMID:27250189

  13. Local stability criterion for the Saturnian ring system

    NASA Astrophysics Data System (ADS)

    Griv, Evgeny

    1998-02-01

    The self-gravitating particulate disk of the Saturnian ring system is studied using linear theory to determine its evolution and stability against gravitational Jeans-type perturbations. The analysis is carried out in approximation of the basically homogeneous and two-dimensional system. In addition, the case is considered with rare collisions between particles when the squared epicyclic frequency κ2 as well as the squared orbital angular frequency Ω 2 greatly exceeds the squared frequency of interparticle physical collisions νc2; that is, the analysis presented here is valid only in the regime of low optical depth in Saturn's rings, τ⋍ ν c/Ω<1 . According to observations, such low optical depth regions can be found in the C ring, the inner portions of the B ring at distances r<100 000 km and the A ring at distances r>123 000 km from the planetary center. The analogy with magnetized plasma problems is utilized by applying the so-called single particle dynamics method (the Lagrangian description): The motion of an "average" particle is considered. In the framework of this analytical method the local dispersion relation for small-amplitude oscillations is derived. Using the dispersion relation, an analysis is given of the dispersion law both for axisymmetric (radial) and nonaxisymmetric (spiral) Jeans perturbations. The main result, which follows from the dispersion relation, is the local stability criterion. The criterion generalizes the well-known Toomre's one ( Astrophys. J.139, 1217-1238, 1964) for spiral gravity perturbations. The dynamical behavior of the different models of Saturn's ring disk is studied by N-body computer simulations in order to confirm the validity of the generalized stability criterion. The numerical method of local simulations (or N-body simulations in a Hill's approximation) is applied. It is shown that the stability criterion obtained from the computer models is in general agreement with the theoretical prediction. It is proposed

  14. Free-surface stability criterion as affected by velocity distribution

    USGS Publications Warehouse

    Cheng-Lung, Chen

    1995-01-01

    This paper examines how the velocity distribution of flow in open channels affects the kinematic and dynamic wave velocities, from which the various forms of the Vedernikov number V can be formulated. When V >1, disturbances created in open-channel flow will amplify in the form of roll waves; when V <1, some (though not all) disturbances will attenuate. A study of the Vedernikov stability criterion reveals that it can be readily deduced within the framework of the kinematic and dynamic wave theories by comparing the kinematic wave velocity to the corresponding dynamic wave velocity. -from Author

  15. Discrete Lange-Newell criterion for dissipative systems.

    PubMed

    Ndzana, Fabien I I; Mohamadou, Alidou; Kofané, Timoleon Crépin

    2009-05-01

    We report on the derivation of the discrete complex Ginzburg-Landau equation with first- and second-neighbor couplings using a nonlinear electrical network. Furthermore, we discuss theoretically and numerically modulational instability of plane carrier waves launched through the line. It is pointed out that the underlying analysis not only spells out the discrete Lange-Newell criterion by the means of the linear stability analysis at which the modulational instability occurs for the generation of a train of ultrashort pulses, but also characterizes the long-time dynamical behavior of the system when the instability grows. PMID:19518586

  16. Forecastability as a Design Criterion in Wind Resource Assessment: Preprint

    SciTech Connect

    Zhang, J.; Hodge, B. M.

    2014-04-01

    This paper proposes a methodology to include the wind power forecasting ability, or 'forecastability,' of a site as a design criterion in wind resource assessment and wind power plant design stages. The Unrestricted Wind Farm Layout Optimization (UWFLO) methodology is adopted to maximize the capacity factor of a wind power plant. The 1-hour-ahead persistence wind power forecasting method is used to characterize the forecastability of a potential wind power plant, thereby partially quantifying the integration cost. A trade-off between the maximum capacity factor and the forecastability is investigated.

  17. Regularity criterion for the 3D Hall-magneto-hydrodynamics

    NASA Astrophysics Data System (ADS)

    Dai, Mimi

    2016-07-01

    This paper studies the regularity problem for the 3D incompressible resistive viscous Hall-magneto-hydrodynamic (Hall-MHD) system. The Kolmogorov 41 phenomenological theory of turbulence [14] predicts that there exists a critical wavenumber above which the high frequency part is dominated by the dissipation term in the fluid equation. Inspired by this idea, we apply an approach of splitting the wavenumber combined with an estimate of the energy flux to obtain a new regularity criterion. The regularity condition presented here is weaker than conditions in the existing criteria (Prodi-Serrin type criteria) for the 3D Hall-MHD system.

  18. Model selection based on robustness criterion with measurement application

    NASA Astrophysics Data System (ADS)

    Brahim-Belhouari, Sofiane; Fleury, Gilles; Davoust, Marie-Eve

    1999-06-01

    Huber's approach to robust estimation is highly fruitful for solving estimation problems with contaminated data or under incomplete information according to the error structure. A simple selection procedure based on robustness to variations of the errors distribution from the assumed one, is proposed. Minimax M-estimator is used to estimate efficiently the parameters and the measurement quantity. A performance deviation criterion is computed by the mean of the Monte Carlo method improved by the Latin Hypercube Sampling. The selection produced is applied to a real measurement problem, grooves dimensioning using Remote Field Eddy Current inspection.

  19. Thermoeconomic analysis: A criterion for the selection of cogeneration systems

    SciTech Connect

    Luz-Silveira, J.; Balestieri, J.A.P.; Santos, A.H.M.; Almeida, R.A.

    1996-12-31

    The economical viability of three cogeneration schemes as supplying alternatives for a hypothetical industrial process has been studied. A cost appropriation method based on Valero`s studies (1986) has been used. This method enables the determination of exergetic flows, the Second Law efficiency of equipment and the monetary costs of the products acquired by the industrial process (steam and electrical energy). The criterion adopted for the selection is the global cost of the supplied products to the industrial process as regarding in Brazilian conditions.

  20. Stronger steerability criterion for more uncertain continuous-variable systems

    NASA Astrophysics Data System (ADS)

    Chowdhury, Priyanka; Pramanik, Tanumoy; Majumdar, A. S.

    2015-10-01

    We derive a fine-grained uncertainty relation for the measurement of two incompatible observables on a single quantum system of continuous variables, and show that continuous-variable systems are more uncertain than discrete-variable systems. Using the derived fine-grained uncertainty relation, we formulate a stronger steering criterion that is able to reveal the steerability of NOON states that has hitherto not been possible using other criteria. We further obtain a monogamy relation for our steering inequality which leads to an, in principle, improved lower bound on the secret key rate of a one-sided device independent quantum key distribution protocol for continuous variables.

  1. Optimization of Polarimetric Contrast Enhancement Based on Fisher Criterion

    NASA Astrophysics Data System (ADS)

    Deng, Qiming; Chen, Jiong; Yang, Jian

    The optimization of polarimetric contrast enhancement (OPCE) is a widely used method for maximizing the received power ratio of a desired target versus an undesired target (clutter). In this letter, a new model of the OPCE is proposed based on the Fisher criterion. By introducing the well known two-class problem of linear discriminant analysis (LDA), the proposed model is to enlarge the normalized distance of mean value between the target and the clutter. In addition, a cross-iterative numerical method is proposed for solving the optimization with a quadratic constraint. Experimental results with the polarimetric SAR (POLSAR) data demonstrate the effectiveness of the proposed method.

  2. On the feature selection criterion based on an approximation of multidimensional mutual information.

    PubMed

    Balagani, Kiran S; Phoha, Vir V

    2010-07-01

    We derive the feature selection criterion presented in [CHECK END OF SENTENCE] and [CHECK END OF SENTENCE] from the multidimensional mutual information between features and the class. Our derivation: 1) specifies and validates the lower-order dependency assumptions of the criterion and 2) mathematically justifies the utility of the criterion by relating it to Bayes classification error. PMID:20489237

  3. Effective Q criterion for disk stability in an external potential

    SciTech Connect

    Jog, Chanda J.

    2014-06-01

    The standard Q criterion (with Q > 1) describes the stability against local, axisymmetric perturbations in a disk supported by rotation and random motion. Most astrophysical disks, however, are under the influence of an external gravitational potential, which can significantly affect their stability. A typical example is a galactic disk embedded in a dark matter halo. Here, we do a linear perturbation analysis for a disk in an external potential and obtain a generalized dispersion relation and the effective stability criterion. An external potential, such as that due to the dark matter halo concentric with the disk, contributes to the unperturbed rotational field and significantly increases its stability. We obtain the values for the effective Q parameter for the Milky Way and for a low surface brightness galaxy, UGC 7321. We find that in each case the stellar disk by itself is barely stable and it is the dark matter halo that stabilizes the disk against local, axisymmetric gravitational instabilities. Thus, the dark matter halo is necessary to ensure local disk stability. This result has been largely missed so far because in practice the Q parameter for a galactic disk is obtained using the observed rotational field that already includes the effect of the halo.

  4. Satisfying the Einstein-Podolsky-Rosen criterion with massive particles.

    PubMed

    Peise, J; Kruse, I; Lange, K; Lücke, B; Pezzè, L; Arlt, J; Ertmer, W; Hammerer, K; Santos, L; Smerzi, A; Klempt, C

    2015-01-01

    In 1935, Einstein, Podolsky and Rosen (EPR) questioned the completeness of quantum mechanics by devising a quantum state of two massive particles with maximally correlated space and momentum coordinates. The EPR criterion qualifies such continuous-variable entangled states, where a measurement of one subsystem seemingly allows for a prediction of the second subsystem beyond the Heisenberg uncertainty relation. Up to now, continuous-variable EPR correlations have only been created with photons, while the demonstration of such strongly correlated states with massive particles is still outstanding. Here we report on the creation of an EPR-correlated two-mode squeezed state in an ultracold atomic ensemble. The state shows an EPR entanglement parameter of 0.18(3), which is 2.4 s.d. below the threshold 1/4 of the EPR criterion. We also present a full tomographic reconstruction of the underlying many-particle quantum state. The state presents a resource for tests of quantum nonlocality and a wide variety of applications in the field of continuous-variable quantum information and metrology. PMID:26612105

  5. SIF-based fracture criterion for interface cracks

    NASA Astrophysics Data System (ADS)

    Ji, Xing

    2016-06-01

    The complex stress intensity factor K governing the stress field of an interface crack tip may be split into two parts, i.e., hat{K} and s^{-iɛ}, so that K=hat{K}s^{-iɛ}, s is a characteristic length and ɛ is the oscillatory index. hat{K} has the same dimension as the classical stress intensity factor and characterizes the interface crack tip field. That means a criterion for interface cracks may be formulated directly with hat{K}, as Irwin (ASME J. Appl. Mech. 24:361-364, 1957) did in 1957 for the classical fracture mechanics. Then, for an interface crack, it is demonstrated that the quasi Mode I and Mode II tip fields can be defined and distinguished from the coupled mode tip fields. Built upon SIF-based fracture criteria for quasi Mode I and Mode II, the stress intensity factor (SIF)-based fracture criterion for mixed mode interface cracks is proposed and validated against existing experimental results.

  6. Refocusing criterion via sparsity measurements in digital holography.

    PubMed

    Memmolo, Pasquale; Paturzo, Melania; Javidi, Bahram; Netti, Paolo A; Ferraro, Pietro

    2014-08-15

    Several automatic approaches have been proposed in the past to compute the refocus distance in digital holography (DH). However most of them are based on a maximization or minimization of a suitable amplitude image contrast measure, regarded as a function of the reconstruction distance parameter. Here we show that, by using the sparsity measure coefficient regarded as a refocusing criterion in the holographic reconstruction, it is possible to recover the focus plane and, at the same time, establish the degree of sparsity of digital holograms, when samples of the diffraction Fresnel propagation integral are used as a sparse signal representation. We employ a sparsity measurement coefficient known as Gini's index thus showing for the first time, to the best of our knowledge, its application in DH, as an effective refocusing criterion. Demonstration is provided for different holographic configurations (i.e., lens and lensless apparatus) and for completely different objects (i.e., a thin pure phase microscopic object as an in vitro cell, and macroscopic puppets) preparation. PMID:25121857

  7. Experimental Study on Peak Shear Strength Criterion for Rock Joints

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Rong, Guan; Hou, Di; Peng, Jun; Zhou, Chuangbing

    2016-03-01

    The three-dimensional (3D) morphology of a rock joint has a great impact on its shear behavior. To study the relationship between the 3D morphological characteristics and the peak shear strength, several tilt tests were conducted on four groups of tensile fractures and direct shear tests were carried out under different constant normal loads (CNL). The normal load ranges from 0.325 to 8.0 MPa. In this study, fresh tensile fractures which were splitted from granite and sandstone samples were used. The morphology of each tensile fracture was measured before direct shear tests. A new peak shear strength criterion for rock joints is proposed using two 3D morphological parameters which are termed as the maximum apparent dip angle θ_{max}^{*} and the roughness parameter C. The calculated peak strengths using the proposed criterion match well with the observed values. In addition, a comparison of the proposed model with the Grasselli's model (2003) and Xia's model (2014) shows that the proposed model is easier in the form and gives a rational improvement. At last, direct shear test data of tensile fractures which are collected from Grasselli (2003) are used to verify the proposed model. It is seen that the proposed model has a reliable estimate of the peak shear strength of tensile fractures and presumably for rock joints.

  8. Satisfying the Einstein–Podolsky–Rosen criterion with massive particles

    PubMed Central

    Peise, J.; Kruse, I.; Lange, K.; Lücke, B.; Pezzè, L.; Arlt, J.; Ertmer, W.; Hammerer, K.; Santos, L.; Smerzi, A.; Klempt, C.

    2015-01-01

    In 1935, Einstein, Podolsky and Rosen (EPR) questioned the completeness of quantum mechanics by devising a quantum state of two massive particles with maximally correlated space and momentum coordinates. The EPR criterion qualifies such continuous-variable entangled states, where a measurement of one subsystem seemingly allows for a prediction of the second subsystem beyond the Heisenberg uncertainty relation. Up to now, continuous-variable EPR correlations have only been created with photons, while the demonstration of such strongly correlated states with massive particles is still outstanding. Here we report on the creation of an EPR-correlated two-mode squeezed state in an ultracold atomic ensemble. The state shows an EPR entanglement parameter of 0.18(3), which is 2.4 s.d. below the threshold 1/4 of the EPR criterion. We also present a full tomographic reconstruction of the underlying many-particle quantum state. The state presents a resource for tests of quantum nonlocality and a wide variety of applications in the field of continuous-variable quantum information and metrology. PMID:26612105

  9. A simplified wave enhancement criterion for moving extreme events

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, Vladimir; Golubkin, Pavel; Chapron, Bertrand

    2015-11-01

    An analytical model is derived to efficiently describe the wave energy distribution along the main transects of a moving extreme weather event. The model essentially builds on a generalization of the self-similar wave growth model and the assumption of a strongly dominant single spectral mode in a given quadrant of the storm. The criterion to anticipate wave enhancement with the generation of trapped abnormal waves defined as gr/ur2≈cT>(ur/V>)1/q, with r, u, and V, radial distance, average sustained wind speed, and translation velocity, respectively. Constants q and cT follow the fetch-law definitions. If forced during a sufficient time scale interval, also defined from this generalized self-similar wave growth model, waves can be trapped and large amplification of the wave energy will occur in the front-right storm quadrant. Remarkably, the group velocity and corresponding wavelength of outrunning wave systems will become wind speed independent and solely related to the translating velocity. The resulting significant wave height also only weakly depends on wind speed, and more strongly on the translation velocity. Compared to altimeter satellite measurements, the proposed analytical solutions for the wave energy distribution demonstrate convincing agreement. As analytically developed, the wave enhancement criterion can provide a rapid evaluation to document the general characteristics of each storm, especially the expected wavefield asymmetry.

  10. Nonextensive statistics and the sheath criterion in collisional plasmas

    SciTech Connect

    Hatami, M. M.

    2015-01-15

    The Bohm criterion in an electropositive plasma containing nonextensively distributed electrons and warm ions is investigated by using a steady state two-fluid model. Taking into account the ion-neutral collisions and finite temperature of ions, a modified Bohm criterion is derived which limits both maximum and minimum allowable velocity of ions at the sheath edge (u{sub 0i}). It is found that the degree of nonextensivity of electrons (q) and temperature of positive ions (T{sub i}) affect only the lower limit of the entrance velocity of ions into the sheath while the degree of ion collisionality (α) influences both lower and upper limits of the ion velocities at the sheath edge. In addition, depending on the value of q, it is shown that the minimum velocity of positive ions at the sheath edge can be greater or smaller than its Maxwellian counterpart. Moreover, it is shown that, depending on the values of α and T{sub i}, the positive ions with subsonic velocity may enter the sheath for either q > 1 or −1 < q < 1. Finally, as a practical application, the density distribution of charged particles in the sheath region is studied for different values of u{sub 0i}, and it is shown that monotonical reduction of the positive ion density distribution occurs only when the velocity of positive ions at the sheath edge lies between two above mentioned limits.

  11. PET image reconstruction: mean, variance, and optimal minimax criterion

    NASA Astrophysics Data System (ADS)

    Liu, Huafeng; Gao, Fei; Guo, Min; Xue, Liying; Nie, Jing; Shi, Pengcheng

    2015-04-01

    Given the noise nature of positron emission tomography (PET) measurements, it is critical to know the image quality and reliability as well as expected radioactivity map (mean image) for both qualitative interpretation and quantitative analysis. While existing efforts have often been devoted to providing only the reconstructed mean image, we present a unified framework for joint estimation of the mean and corresponding variance of the radioactivity map based on an efficient optimal min-max criterion. The proposed framework formulates the PET image reconstruction problem to be a transformation from system uncertainties to estimation errors, where the minimax criterion is adopted to minimize the estimation errors with possibly maximized system uncertainties. The estimation errors, in the form of a covariance matrix, express the measurement uncertainties in a complete way. The framework is then optimized by ∞-norm optimization and solved with the corresponding H∞ filter. Unlike conventional statistical reconstruction algorithms, that rely on the statistical modeling methods of the measurement data or noise, the proposed joint estimation stands from the point of view of signal energies and can handle from imperfect statistical assumptions to even no a priori statistical assumptions. The performance and accuracy of reconstructed mean and variance images are validated using Monte Carlo simulations. Experiments on phantom scans with a small animal PET scanner and real patient scans are also conducted for assessment of clinical potential.

  12. SIF-based fracture criterion for interface cracks

    NASA Astrophysics Data System (ADS)

    Ji, Xing

    2016-01-01

    The complex stress intensity factor K governing the stress field of an interface crack tip may be split into two parts, i.e., hat{K} and s^{-i\\varepsilon } , so that K=hat{K}s^{-i\\varepsilon }, s is a characteristic length and \\varepsilon is the oscillatory index. hat{K} has the same dimension as the classical stress intensity factor and characterizes the interface crack tip field. That means a criterion for interface cracks may be formulated directly with hat{K} , as Irwin (ASME J. Appl. Mech. 24:361-364, 1957) did in 1957 for the classical fracture mechanics. Then, for an interface crack, it is demonstrated that the quasi Mode I and Mode II tip fields can be defined and distinguished from the coupled mode tip fields. Built upon SIF-based fracture criteria for quasi Mode I and Mode II, the stress intensity factor (SIF)-based fracture criterion for mixed mode interface cracks is proposed and validated against existing experimental results.

  13. A procedure for seiche analysis with Bayesian information criterion

    NASA Astrophysics Data System (ADS)

    Aichi, Masaatsu

    2016-04-01

    Seiche is a standing wave in enclosed or semi-enclosed water body. Its amplitude irregularly changes in time due to weather condition etc. Then, extracting seiche signal is not easy by usual methods for time series analysis such as fast Fourier transform (FFT). In this study, a new method for time series analysis with Bayesian information criterion was developed to decompose seiche, tide, long-term trend and residual components from time series data of tide stations. The method was developed based on the maximum marginal likelihood estimation of tide amplitudes, seiche amplitude, and trend components. Seiche amplitude and trend components were assumed that they gradually changes as second derivative in time was close to zero. These assumptions were incorporated as prior distributions. The variances of prior distributions were estimated by minimizing Akaike-Bayes information criterion (ABIC). The frequency of seiche was determined by Newton method with initial guess by FFT. The accuracy of proposed method was checked by analyzing synthetic time series data composed of known components. The reproducibility of the original components was quite well. The proposed method was also applied to the actual time series data of sea level observed by tide station and the strain of coastal rock masses observed by fiber Bragg grating sensor in Aburatsubo Bay, Japan. The seiche in bay and its response of rock masses were successfully extracted.

  14. Environmental equity as a criterion for water management

    NASA Astrophysics Data System (ADS)

    Grande, M.; Galvão, C.; Miranda, L.; Rufino, I.

    2014-09-01

    Environmental equity is a concept derived from the (un)equal exposure to environmental degradation by different social groups, usually minorities and low-income people exposed to major environmental risks, also known as environmental justice. It is assumed that no group of people, independent of race, ethnicity or socio-economic class, should support, either in concentrated or unevenly distributed form, the negative environmental impacts resulting from industrial, agricultural, commercial and infrastructure activities or government programs and policies. In this paper the concept of environmental equity is explored as a criterion for water management through the analysis of a typical coupled human-natural system: the Epitácio Pessoa Reservoir, located in the semi-arid region of Brazil. Inefficient water resource management has caused unequal access to water by the population, particularly during drought periods. However, census data indicate that population have practically the same access to water, which actually is not able to reflect the actual picture. This study argues that environmental equity can be an additional criterion to improve water management.

  15. Multi-Criterion Preliminary Design of a Tetrahedral Truss Platform

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey

    1995-01-01

    An efficient method is presented for multi-criterion preliminary design and demonstrated for a tetrahedral truss platform. The present method requires minimal analysis effort and permits rapid estimation of optimized truss behavior for preliminary design. A 14-m-diameter, 3-ring truss platform represents a candidate reflector support structure for space-based science spacecraft. The truss members are divided into 9 groups by truss ring and position. Design variables are the cross-sectional area of all members in a group, and are either 1, 3 or 5 times the minimum member area. Non-structural mass represents the node and joint hardware used to assemble the truss structure. Taguchi methods are used to efficiently identify key points in the set of Pareto-optimal truss designs. Key points identified using Taguchi methods are the maximum frequency, minimum mass, and maximum frequency-to-mass ratio truss designs. Low-order polynomial curve fits through these points are used to approximate the behavior of the full set of Pareto-optimal designs. The resulting Pareto-optimal design curve is used to predict frequency and mass for optimized trusses. Performance improvements are plotted in frequency-mass (criterion) space and compared to results for uniform trusses. Application of constraints to frequency and mass and sensitivity to constraint variation are demonstrated.

  16. Job shop scheduling problem with late work criterion

    NASA Astrophysics Data System (ADS)

    Piroozfard, Hamed; Wong, Kuan Yew

    2015-05-01

    Scheduling is considered as a key task in many industries, such as project based scheduling, crew scheduling, flight scheduling, machine scheduling, etc. In the machine scheduling area, the job shop scheduling problems are considered to be important and highly complex, in which they are characterized as NP-hard. The job shop scheduling problems with late work criterion and non-preemptive jobs are addressed in this paper. Late work criterion is a fairly new objective function. It is a qualitative measure and concerns with late parts of the jobs, unlike classical objective functions that are quantitative measures. In this work, simulated annealing was presented to solve the scheduling problem. In addition, operation based representation was used to encode the solution, and a neighbourhood search structure was employed to search for the new solutions. The case studies are Lawrence instances that were taken from the Operations Research Library. Computational results of this probabilistic meta-heuristic algorithm were compared with a conventional genetic algorithm, and a conclusion was made based on the algorithm and problem.

  17. The limits of the Bohm criterion in collisional plasmas

    SciTech Connect

    Valentini, H.-B.; Kaiser, D.

    2015-05-15

    The sheath formation within a low-pressure collisional plasma is analysed by means of a two-fluid model. The Bohm criterion takes into account the effects of the electric field and the inertia of the ions. Numerical results yield that these effects contribute to the space charge formation, only, if the collisionality is lower than a relatively small threshold. It follows that a lower and an upper limit of the drift speed of the ions exist where the effects treated by Bohm can form a sheath. This interval becomes narrower as the collisionality increases and vanishes at the mentioned threshold. Above the threshold, the sheath is mainly created by collisions and the ionisation. Under these conditions, the sheath formation cannot be described by means of Bohm like criteria. In a few references, a so-called upper limit of the Bohm criterion is stated for collisional plasmas where the momentum equation of the ions is taken into account, only. However, the present paper shows that this limit results in an unrealistically steep increase of the space charge density towards the wall, and, therefore, it yields no useful limit of the Bohm velocity.

  18. Model Selection and Psychological Theory: A Discussion of the Differences between the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC)

    ERIC Educational Resources Information Center

    Vrieze, Scott I.

    2012-01-01

    This article reviews the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) in model selection and the appraisal of psychological theory. The focus is on latent variable models, given their growing use in theory testing and construction. Theoretical statistical results in regression are discussed, and more important…

  19. A Path-Independent Forming Limit Criterion for Stamping Simulations

    NASA Astrophysics Data System (ADS)

    Zhu, Xinhai; Chappuis, Laurent; Xia, Z. Cedric

    2005-08-01

    Forming Limit Diagram (FLD) has been proved to be a powerful tool for assessing necking failures in sheet metal forming analysis for majority of stamping operations over the last three decades. However, experimental evidence and theoretical analysis suggest that its applications are limited to linear or almost linear strain paths during its deformation history. Abrupt changes or even gradual deviations from linear strain-paths will shift forming limit curves from their original values, a situation that occurs in vast majority of sequential stamping operations such as where the drawing process is followed by flanging and re-strike processes. Various forming limit models have been put forward recently to provide remedies for the problem, noticeably stress-based and strain gradient-based forming limit criteria. This study presents an alternative path-independent forming limit criterion. Instead of traditional Forming Limit Diagrams (FLD) which are constructed in terms of major - minor principal strains throughout deformation history, the new criterion defines a critical effective strain ɛ¯* as the limit strain for necking, and it is shown that ɛ¯* can be expressed as a function of current strain rate state and material work hardening properties, without the need of explicitly considering strain-path effects. It is given by ɛ¯* = f(β, k, n) where β = dɛ2/dɛ1 at current deformation state, and k and n are material strain hardening parameters if a power law is assumed. The analysis is built upon previous work by Storen and Rice [1975] and Zhu et al [2002] with the incorporation of anisotropic yield models such as Hill'48 for quadratic orthotropic yield and Hill'79 for non-quadratic orthotropic yield. Effects of anisotropic parameters such as R-values and exponent n-values on necking are investigated in detail for a variety of strain paths. Results predicted according to current analysis are compared against experimental data gathered from literature and good

  20. Criterion Related Validity of Karate Specific Aerobic Test (KSAT)

    PubMed Central

    Chaabene, Helmi; Hachana, Younes; Franchini, Emerson; Tabben, Montassar; Mkaouer, Bessem; Negra, Yassine; Hammami, Mehrez; Chamari, Karim

    2015-01-01

    Background: Karate is one the most popular combat sports in the world. Physical fitness assessment on a regular manner is important for monitoring the effectiveness of the training program and the readiness of karatekas to compete. Objectives: The aim of this research was to examine the criterion related to validity of the karate specific aerobic test (KSAT) as an indicator of aerobic level of karate practitioners. Patients and Methods: Cardiorespiratory responses, aerobic performance level through both treadmill laboratory test and YoYo intermittent recovery test level 1 (YoYoIRTL1) as well as time to exhaustion in the KSAT test (TE’KSAT) were determined in a total of fifteen healthy international karatekas (i.e. karate practitioners) (means ± SD: age: 22.2 ± 4.3 years; height: 176.4 ± 7.5 cm; body mass: 70.3 ± 9.7 kg and body fat: 13.2 ± 6%). Results: Peak heart rate obtained from KSAT represented ~99% of maximal heart rate registered during the treadmill test showing that KSAT imposes high physiological demands. There was no significant correlation between KSAT’s TE and relative (mL/min kg) treadmill maximal oxygen uptake (r = 0.14; P = 0.69; [small]). On the other hand, there was a significant relationship between KSAT’s TE and the velocity associated with VO2max (vVO2max) (r = 0.67; P = 0.03; [large]) as well as the velocity at VO2 corresponding to the second ventilatory threshold (vVO2 VAT) (r = 0.64; P = 0.04; [large]). Moreover, significant relationship was found between TE’s KSAT and both the total distance covered and parameters of intermittent endurance measured through YoYoIRTL1. Conclusions: The KSAT has not proved to have indirect criterion related validity as no significant correlations have been found between TE’s KSAT and treadmill VO2max. Nevertheless, as correlated to other aerobic fitness variables, KSAT can be considered as an indicator of karate specific endurance. The establishment of the criterion related validity of the KSAT

  1. Preliminary Studies for Three Experiments at Treiman-Yang Criterion

    NASA Astrophysics Data System (ADS)

    Kres, I. V.; Kondratyev, V. N.; Cherubini, S.; Spitaleri, C.

    2016-05-01

    Nuclear reactions with three bodies in their final state may proceed through different reaction mechanisms. The Feynman graph technique has been widely used to describe such reactions. However, it is very difficult in general to select the graphs that dominate in given process. The Treiman-Yang criterion is one of the most powerful experimental tests for verifying the pole approximation prediction when describing a quasi-free reaction mechanism. We propose the theoretical study of the H2(B10, α Be7)ns, H1(B11, α1α2)αs, He3(Be9, α1α2)αs reactions at different energies. The preliminary study helps to check the existence of a QF channel by using the TY creterion.

  2. Criterion and incremental validity of the emotion regulation questionnaire

    PubMed Central

    Ioannidis, Christos A.; Siegling, A. B.

    2015-01-01

    Although research on emotion regulation (ER) is developing, little attention has been paid to the predictive power of ER strategies beyond established constructs. The present study examined the incremental validity of the Emotion Regulation Questionnaire (ERQ; Gross and John, 2003), which measures cognitive reappraisal and expressive suppression, over and above the Big Five personality factors. It also extended the evidence for the measure's criterion validity to yet unexamined criteria. A university student sample (N = 203) completed the ERQ, a measure of the Big Five, and relevant cognitive and emotion-laden criteria. Cognitive reappraisal predicted positive affect beyond personality, as well as experiential flexibility and constructive self-assertion beyond personality and affect. Expressive suppression explained incremental variance in negative affect beyond personality and in experiential flexibility beyond personality and general affect. No incremental effects were found for worry, social anxiety, rumination, reflection, and preventing negative emotions. Implications for the construct validity and utility of the ERQ are discussed. PMID:25814967

  3. Criterion and incremental validity of the emotion regulation questionnaire.

    PubMed

    Ioannidis, Christos A; Siegling, A B

    2015-01-01

    Although research on emotion regulation (ER) is developing, little attention has been paid to the predictive power of ER strategies beyond established constructs. The present study examined the incremental validity of the Emotion Regulation Questionnaire (ERQ; Gross and John, 2003), which measures cognitive reappraisal and expressive suppression, over and above the Big Five personality factors. It also extended the evidence for the measure's criterion validity to yet unexamined criteria. A university student sample (N = 203) completed the ERQ, a measure of the Big Five, and relevant cognitive and emotion-laden criteria. Cognitive reappraisal predicted positive affect beyond personality, as well as experiential flexibility and constructive self-assertion beyond personality and affect. Expressive suppression explained incremental variance in negative affect beyond personality and in experiential flexibility beyond personality and general affect. No incremental effects were found for worry, social anxiety, rumination, reflection, and preventing negative emotions. Implications for the construct validity and utility of the ERQ are discussed. PMID:25814967

  4. Theoretical fracture criterion of the layered elastic composite materials

    NASA Astrophysics Data System (ADS)

    Ćilli, A.

    2016-03-01

    The theoretical fracture limit in compression of a composite material with two isotropic homogeneous elastic layers is studied using the piecewise homogeneous body model with the three-dimensional theory of elasticity. We assumed the layers have the initial local imperfections and these imperfections are moved with respect to each other by the same length which is expressed by the angle β. The aim of the investigations was to study the influence of this length on the values of the theoretical fracture criterion limit. The numerical results for the influence of the initial local imperfections on the values of fracture limit are presented. It is therefore concluded that the values of the theoretical fracture limit increase with the length of the shifting.

  5. Should cognitive deficit be a diagnostic criterion for schizophrenia?

    PubMed Central

    Lewis, Ralph

    2004-01-01

    This review examines the question of whether cognitive deficits in schizophrenia are sufficiently reliable, stable and specific to warrant inclusion in the diagnostic criteria for schizophrenia. The literature provides evidence that cognitive deficits are highly prevalent and fairly marked in adult patients with schizophrenia. Similar deficits have been found in children and adolescents with schizophrenia, and in children before they exhibit the signs and symptoms of schizophrenia. These deficits may in fact be central to the pathophysiology underlying the development of overt psychosis in schizophrenia. The deficits appear to be relatively stable across the course of the illness. They are generally more severe in schizophrenia than in affective disorders and may have a relatively specific pattern in schizophrenia. It is concluded that the evidence that cognitive deficits are a core feature of schizophrenia is sufficiently compelling to warrant inclusion of these deficits in the diagnostic criteria for schizophrenia, at least as a nonessential criterion. PMID:15069464

  6. Failure criterion of glass fabric reinforced plastic laminates

    NASA Technical Reports Server (NTRS)

    Haga, O.; Hayashi, N.; Kasuya, K.

    1986-01-01

    Failure criteria are derived for several modes of failure (in unaxial tensile or compressive loading, or biaxial combined tensile-compressive loading) in the case of closely woven plain fabric, coarsely-woven plain fabric, or roving glass cloth reinforcements. The shear strength in the interaction formula is replaced by an equation dealing with tensile or compressive strength in the direction making a 45 degree angle with one of the anisotropic axes, for the uniaxial failure criteria. The interaction formula is useful as the failure criterion in combined tension-compression biaxial failure for the case of closely woven plain fabric laminates, but poor agreement is obtained in the case of coarsely woven fabric laminates.

  7. Attractor radius, a new determination criterion of predictability limit

    NASA Astrophysics Data System (ADS)

    Liu, Deqiang; Ding, Ruiqiang; Li, Jianping; Feng, Jie

    2014-05-01

    Firstly, the definition of the attractor radius was given and then the property of that the attractor radius (AR) in a given n-dimensional attractor A is a constant was proved in theory. Secondly, the SV of the square of the RMS difference was separated into two components - the systematic error and the attractor radius, and it was proved that the observed global climatological RMS (OCR) difference is not equal to 71% of the SV of the RMS difference when the systematic error is existed, however, it is always equal to 71% of the AR. Then the physical understanding of the AR and also the predictability limit determinated by it were discussed. Finally, the spatial distributions of the predictability limit calculated from CFSv2 data by different criterions were compared.

  8. Decision processes in recognition memory: criterion shifts and the list-strength paradigm.

    PubMed

    Hirshman, E

    1995-03-01

    This article focuses on decision processes in recognition memory. It begins with investigation of the hypothesis that the measured criterion increases systematically with the memorability of old items. Three experiments using the list-strength paradigm, and a review of the prior literature, present results consistent with this hypothesis. Several psychological models of criterion placement are examined, generating different predictions about the relative sizes of criterion shifts for strong and weak items. A range model, in which criterion placement depends on the estimated range of the old and new distributions, predicts that criterion shifts should be larger for weak items; this result emerges in a reanalysis of prior studies. The general discussion elaborates on how a focus on criterion placement can explain the mirror effect (Glanzer, Adams, Iverson, & Kim, 1993) and provides a framework for testing Shiffrin, Ratcliff, and Clark's (1990) claims about why null effects of list strength occur with repetition. PMID:7738502

  9. An optimality criterion for sizing members of heated structures with temperature constraints. [considering aerospace structures

    NASA Technical Reports Server (NTRS)

    Rao, G. V.; Shore, C. P.; Narayanaswami, R.

    1977-01-01

    A thermal optimality criterion is presented for sizing members of heated structures with multiple temperature constraints. The optimality criterion is similar to an existing optimality criterion for design of mechanically loaded structures with displacement constraints. Effectiveness of the thermal optimality criterion is assessed by applying it to one- and two-dimensional thermal problems where temperatures can be controlled by varying the material distribution in the structure. Results obtained from the optimality criterion agree within 2 percent with results from a closed-form solution and with results from a mathematical programming technique. The thermal optimality criterion augments existing optimality criteria for strength and stiffness related constraints and offers the possibility of extension of optimality techniques to sizing structures with combined thermal and mechanical loading.

  10. A heuristic criterion for instability to fragmentation in rotating, interstellar clouds

    NASA Technical Reports Server (NTRS)

    Boss, A. P.

    1982-01-01

    A heuristic criterion, based on linear perturbation analysis, is applied to the initial growth of density perturbations in isothermal or adiabatic gas clouds, with initially uniform density and uniform rotation. The heuristic criterion is shown to be consistent with the available results from numerical calculations of cloud collapse. The criterion predicts that perturbations varying as cos(m-phi) will be most likely to grow when m is small, unless the cloud is nearly pressureless.

  11. A Heuristic Criterion for Instability to Fragmentation in Rotating, Interstellar Clouds

    NASA Technical Reports Server (NTRS)

    Boss, Alan Paul

    1982-01-01

    A heuristic criterion, based on linear perturbation analysis, is applied to the initial growth of density perturbations in isothermal or adiabatic gas clouds, with initially uniform density and uniform rotation. The heuristic criterion is shown to be consistent with the available results from numerical calculations of cloud collapse. The criterion predicts that perturbations varying as cos (m(phi)) will be most likely to grow when )pi is small, unless the cloud is nearly pressureless.

  12. SALT DAMAGE CRITERION PROOF-OF-CONCEPT RESEARCH

    SciTech Connect

    Kerry L. DeVries; Kirby D. Mellegard; Gary D. Callahan

    2001-12-01

    This document is the annual technical progress report for Department of Energy Contract No. DE-FC26-00NT41026 entitled Proof-of-Concept Research for an Advanced Design Criterion to Improve Working Gas Capacity for Natural Gas Storage Caverns in Salt Formations. This report covers the reporting period from October 1, 2000, through September 30, 2001. During this reporting period, the project was initiated and work was performed to develop structural models that will be used to evaluate two compressed natural gas storage caverns in the McIntosh Dome northwest of Mobile, Alabama. Information necessary to define the structural models include site-specific stress, temperature, geometry, stratigraphy, and operating scenarios in the dome and for the caverns. Additionally, material model development for the salt at the McIntosh Dome was initiated. Material model development activities include acquisition of salt core for testing, laboratory testing, and regression analyses to determine site-specific model parameter values that describe the behavior of salt around a storage cavern. Although not performed during this reporting period, the information and models developed will be used to perform advanced design storage cavern analyses for the Bay Gas caverns to determine the operating pressure ranges to maintain stable conditions.

  13. Lyapunov Exponent Criterion in the CR3BP

    NASA Astrophysics Data System (ADS)

    Quarles, Billy; Eberle, Jason; Cuntz, Manfred; Musielak, Zdzislaw

    2010-10-01

    Our specific focus is to describe the motion of an extra solar planet in a binary star system. We aim to accomplish this by using the methods of chaos theory as an alternate method to our previously established Hodograph method in the circular restricted 3-body problem (CR3BP). Previously Eberle et al. (2010) has shown that a parameter space exists depending only on the mass ratio μ and distance ratio ρo which allowed them to identify regions of stability. Our method will validate the previous results while also providing more information relating to the presence of resonances and their effects on orbital stability. We extend the previous studies by increasing the simulation time, applying the method of Lyapunov exponents, calculating the time series spectrum of the orbit, and determining the Lyapunov dimension. The obtained results demonstrate when a system becomes unstable by orbital energy criterion and the method of Lyapunov exponents provides a quantitative classification scale to characterize the instability. By applying the maximum Lyapunov exponent (MLE) to the parameter space, we determine a region of stability with MLE values larger than the surrounding region. The time series spectra and the Lyapunov Dimension methods are used to illustrate the reasons behind the stability plateau which eludes to the resonance phenomena.

  14. Robust Deep Network with Maximum Correntropy Criterion for Seizure Detection

    PubMed Central

    Wang, Yueming; Zhu, Junming; Zheng, Xiaoxiang

    2014-01-01

    Effective seizure detection from long-term EEG is highly important for seizure diagnosis. Existing methods usually design the feature and classifier individually, while little work has been done for the simultaneous optimization of the two parts. This work proposes a deep network to jointly learn a feature and a classifier so that they could help each other to make the whole system optimal. To deal with the challenge of the impulsive noises and outliers caused by EMG artifacts in EEG signals, we formulate a robust stacked autoencoder (R-SAE) as a part of the network to learn an effective feature. In R-SAE, the maximum correntropy criterion (MCC) is proposed to reduce the effect of noise/outliers. Unlike the mean square error (MSE), the output of the new kernel MCC increases more slowly than that of MSE when the input goes away from the center. Thus, the effect of those noises/outliers positioned far away from the center can be suppressed. The proposed method is evaluated on six patients of 33.6 hours of scalp EEG data. Our method achieves a sensitivity of 100% and a specificity of 99%, which is promising for clinical applications. PMID:25105136

  15. A criterion for lattice supersymmetry: cyclic Leibniz rule

    NASA Astrophysics Data System (ADS)

    Kato, Mitsuhiro; Sakamoto, Makoto; So, Hiroto

    2013-05-01

    It is old folklore that the violation of Leibniz rule on a lattice is an obstruction for constructing a lattice supersymmetric model. While it is still true for full supersymmetry, we show that a slightly modified form of the Leibniz rule, which we call cyclic Leibniz rule (CLR), is actually a criterion for the existence of partial lattice supersymmetry. In one dimension, we find sets of lattice difference operator and field multiplication smeared over lattice which satisfy the CLR under some natural assumptions such as translational invariance and locality. Thereby we construct a model of supersymmetric lattice quantum mechanics without spoiling locality. The CLR relation is coincident with the condition that the vanishing of the so-called surface term in the construction by lattice Nicolai map. We can construct superfield formalism with arbitrary superpotential. This also enables us to apply safely a localization technique to our model, because the kinetic term and the interaction terms of our model are independently invariant under the supersymmetry transformation. A preliminary attempt in finding a solution for the higher dimensional case is also discussed.

  16. A criterion measurement model for health behavior change.

    PubMed

    Velicer, W F; Rossi, J S; Diclemente, C C; Prochaska, J O

    1996-01-01

    Researchers in the field of health behavior change have traditionally relied on a univariate criterion measure to evaluate the efficacy of an intervention. Such measures have superficial face validity but suffer from a number of problems: (a) lack of precise definitions; (b) poor statistical power; and (c) a lack of meaningfulness for some aspects of the problem. As an alternative, a theoretical model is developed that attempts to define more appropriate multivariate sets of dependent variables for the study of health behavior change. The model involves three separate constructs: Positive Evaluation Strength, Negative Evaluation Strength, and Habit Strength. The pattern of change for each construct is described across four stages of change: Precontemplation, Contemplation, Action, and Maintenance. For each construct, two thresholds are proposed representing the ability of the environment to modify the construct. Four tests of the model are provided from existing data sets. First, a structural model analysis was used to test if the proposed measurement model adequately fits the data. Second, a dynamic typology approach produced profiles of change that are consistent with the model. Third, a time series analysis provided support for the assumed model. Fourth, longitudinal, five-wave panel design was employed to test if the relation between the two cognitive variables (Pros and Cons) and the behavioral measure (Habit Strength) was consistent with the model. Implications for alternative intervention strategies are discussed. PMID:8876758

  17. Robust deep network with maximum correntropy criterion for seizure detection.

    PubMed

    Qi, Yu; Wang, Yueming; Zhang, Jianmin; Zhu, Junming; Zheng, Xiaoxiang

    2014-01-01

    Effective seizure detection from long-term EEG is highly important for seizure diagnosis. Existing methods usually design the feature and classifier individually, while little work has been done for the simultaneous optimization of the two parts. This work proposes a deep network to jointly learn a feature and a classifier so that they could help each other to make the whole system optimal. To deal with the challenge of the impulsive noises and outliers caused by EMG artifacts in EEG signals, we formulate a robust stacked autoencoder (R-SAE) as a part of the network to learn an effective feature. In R-SAE, the maximum correntropy criterion (MCC) is proposed to reduce the effect of noise/outliers. Unlike the mean square error (MSE), the output of the new kernel MCC increases more slowly than that of MSE when the input goes away from the center. Thus, the effect of those noises/outliers positioned far away from the center can be suppressed. The proposed method is evaluated on six patients of 33.6 hours of scalp EEG data. Our method achieves a sensitivity of 100% and a specificity of 99%, which is promising for clinical applications. PMID:25105136

  18. A New Criterion for Demarcating Life from Non-Life

    NASA Astrophysics Data System (ADS)

    van Hateren, J. H.

    2013-12-01

    Criteria for demarcating life from non-life are important for deciding whether new candidate systems, either discovered extraterrestrially or constructed in the laboratory, are genuinely alive or not. They are also important for understanding the origin of life and its evolution. Current criteria are either too restrictive or too extensive. The new criterion proposed here poses that a system is living when it is capable of utilizing active causation, at evolutionary or behavioural timescales. Active causation is produced when the organism uses an estimate of its own Darwinian fitness to modulate the variance of stochasticity that drives hereditary or behavioural changes. The changes are subsequently fed back to the fitness estimate and used in the next cycle of a feedback loop. The ability to use a self-estimated fitness in this way is an evolved property of the organism, and the way in which fitness is estimated is therefore controlled and stabilized by Darwinian evolution. The hereditary and behavioural trajectories resulting from this mechanism combine predictability with unpredictability, and the mechanism produces a form of self-directed agency in living organisms that is absent from non-living systems.

  19. General criterion for the entanglement of two indistinguishable particles

    SciTech Connect

    Ghirardi, GianCarlo; Marinatto, Luca

    2004-07-01

    We relate the notion of entanglement for quantum systems composed of two identical constituents to the impossibility of attributing a complete set of properties to both particles. This implies definite constraints on the mathematical form of the state vector associated with the whole system. We then analyze separately the cases of fermion and boson systems, and we show how the consideration of both the Slater-Schmidt number of the fermionic and bosonic analog of the Schmidt decomposition of the global state vector and the von Neumann entropy of the one-particle reduced density operators can supply us with a consistent criterion for detecting entanglement. In particular, the consideration of the von Neumann entropy is particularly useful in deciding whether the correlations of the considered states are simply due to the indistinguishability of the particles involved or are a genuine manifestation of the entanglement. The treatment leads to a full clarification of the subtle aspects of entanglement of two identical constituents which have been a source of embarrassment and of serious misunderstandings in the recent literature.

  20. A novel SURE-based criterion for parametric PSF estimation.

    PubMed

    Xue, Feng; Blu, Thierry

    2015-02-01

    We propose an unbiased estimate of a filtered version of the mean squared error--the blur-SURE (Stein's unbiased risk estimate)--as a novel criterion for estimating an unknown point spread function (PSF) from the degraded image only. The PSF is obtained by minimizing this new objective functional over a family of Wiener processings. Based on this estimated blur kernel, we then perform nonblind deconvolution using our recently developed algorithm. The SURE-based framework is exemplified with a number of parametric PSF, involving a scaling factor that controls the blur size. A typical example of such parametrization is the Gaussian kernel. The experimental results demonstrate that minimizing the blur-SURE yields highly accurate estimates of the PSF parameters, which also result in a restoration quality that is very similar to the one obtained with the exact PSF, when plugged into our recent multi-Wiener SURE-LET deconvolution algorithm. The highly competitive results obtained outline the great potential of developing more powerful blind deconvolution algorithms based on SURE-like estimates. PMID:25531950

  1. A Physics-Based Temperature Stabilization Criterion for Thermal Testing

    NASA Technical Reports Server (NTRS)

    Rickman, Steven L.; Ungar, Eugene K.

    2009-01-01

    Spacecraft testing specifications differ greatly in the criteria they specify for stability in thermal balance tests. Some specify a required temperature stabilization rate (the change in temperature per unit time, dT/dt), some specify that the final steady-state temperature be approached to within a specified difference, delta T , and some specify a combination of the two. The particular values for temperature stabilization rate and final temperature difference also vary greatly between specification documents. A one-size-fits-all temperature stabilization rate requirement does not yield consistent results for all test configurations because of differences in thermal mass and heat transfer to the environment. Applying a steady-state temperature difference requirement is problematic because the final test temperature is not accurately known a priori, especially for powered configurations. In the present work, a simplified, lumped-mass analysis has been used to explore the applicability of these criteria. A new, user-friendly, physics-based approach is developed that allows the thermal engineer to determine when an acceptable level of temperature stabilization has been achieved. The stabilization criterion can be predicted pre-test but must be refined during test to allow verification that the defined level of temperature stabilization has been achieved.

  2. Akaike information criterion to select well-fit resist models

    NASA Astrophysics Data System (ADS)

    Burbine, Andrew; Fryer, David; Sturtevant, John

    2015-03-01

    In the field of model design and selection, there is always a risk that a model is over-fit to the data used to train the model. A model is well suited when it describes the physical system and not the stochastic behavior of the particular data collected. K-fold cross validation is a method to check this potential over-fitting to the data by calibrating with k-number of folds in the data, typically between 4 and 10. Model training is a computationally expensive operation, however, and given a wide choice of candidate models, calibrating each one repeatedly becomes prohibitively time consuming. Akaike information criterion (AIC) is an information-theoretic approach to model selection based on the maximized log-likelihood for a given model that only needs a single calibration per model. It is used in this study to demonstrate model ranking and selection among compact resist modelforms that have various numbers and types of terms to describe photoresist behavior. It is shown that there is a good correspondence of AIC to K-fold cross validation in selecting the best modelform, and it is further shown that over-fitting is, in most cases, not indicated. In modelforms with more than 40 fitting parameters, the size of the calibration data set benefits from additional parameters, statistically validating the model complexity.

  3. An improved criterion for new particle formation in diverse environments

    SciTech Connect

    Kuang, C.; Riipinen, I.; Sihto, S.-L.; Kulmala, M.; McCormick, A.; McMurry, P.

    2010-03-15

    A dimensionless theory for new particle formation (NPF) was developed, using an aerosol population balance model incorporating recent developments in nucleation rates and measured particle growth rates. Based on this theoretical analysis, it was shown that a dimensionless parameter Lg, characterizing the ratio of the particle scavenging loss rate to the particle growth rate, exclusively determined whether or not NPF would occur on a particular day. This parameter determines the probability that a nucleated particle will grow to a detectable size before being lost by coagulation with the pre-existing aerosol. Cluster-cluster coagulation was shown to contribute negligibly to this survival probability under conditions pertinent to the atmosphere. Data acquired during intensive measurement campaigns in Tecamac (MILAGRO), Atlanta (ANARChE), Boulder, and Hyytiala (QUEST II, QUEST IV, and EUCAARI) were used to test the validity of Lg as an NPF criterion. Measurements included aerosol size distributions down to 3 nm and gas-phase sulfuric acid concentrations. The model was applied to 77 NPF events and 19 non-events (characterized by growth of pre-existing aerosol without NPF) measured in diverse environments with broad ranges in sulfuric acid concentrations, ultrafine number concentrations, aerosol surface areas, and particle growth rates (nearly two orders of magnitude). Across this diverse data set, a nominal value of Lg = 0.7 was found to determine the boundary for the occurrence of NPF, with NPF occurring when Lg < 0.7 and being suppressed when Lg > 0.7. Moreover, nearly 45% of measured Lg values associated with NPF fell in the relatively narrow range of 0.1 < Lg < 0.3.

  4. Determining the Bohm criterion in plasmas with two ion species

    SciTech Connect

    Baalrud, S. D.; Hegna, C. C.

    2011-02-15

    A model that uniquely determines the flow speed of each ion species at the sheath edge of two ion species plasmas is developed. In this analysis, ion-ion two-stream instabilities can play an important role because they significantly enhance the friction between ion species. Two-stream instabilities arise when the difference in flow speeds between the ion species exceeds a critical value: V{sub 1}-V{sub 2}{identical_to}{Delta}V{>=}{Delta}V{sub c}. The resultant instability-enhanced friction rapidly becomes so strong that {Delta}V cannot significantly exceed {Delta}V{sub c}. Using the condition provided by {Delta}V={Delta}V{sub c} and the generalized Bohm criterion, the speed of each ion species is uniquely determined as it leaves a quasineutral plasma and enters a sheath. Previous work [S. D. Baalrud et al., Phys. Rev. Lett. 103, 205002 (2009)] considered the cold ion limit (T{sub i}{yields}0), in which case {Delta}V{sub c}{yields}0 and each ion species obtains a common ''system'' sound speed at the sheath edge. Finite ion temperatures are accounted for in this work. The result is that {Delta}V{sub c} depends on the density and thermal speed of each ion species; {Delta}V{sub c} has a minimum when the density ratio of the two ion species is near one, and becomes larger as the density ratio deviates from unity. As {Delta}V{sub c} increases, the speed of each ion species approaches its individual sound speed at the sheath edge.

  5. Establishment of reference intervals and transfusion criterion for Sonoclot analysis.

    PubMed

    Zhang, Zhen-Lu; Chen, You-Ping; Tao, Cui-Hua; Liu, Xiao-Hui; Li, Meng-Ya; Zhou, Xin

    2016-08-01

    Sonoclot analyzer has been widely used in many countries. But the reference intervals provided by the manufacturer were derived from only 45 participants, and there was no cut-off value for transfusion for Sonoclot analysis. This study aimed to establish reference intervals and transfusion criterion for Sonoclot analysis. Volunteers were recruited from healthy Chinese adults and patients undergoing cardiac surgery. Blood samples were withdrawn from forearm vein and measured for activated clotting time (ACT), clot rate (CR), platelet function (PF), activated partial thromboplastin time (APTT), fibrinogen concentration (FIB), and platelet count (PLT). The reference intervals were determined by the nonparametric method. Cut-off values were determined by the receiver operating characteristics curve. A total of 135 healthy volunteers and 281 patients were enrolled. The 95% reference intervals were 96-195 s, 22-51 signal U/min, >1.6 for ACT, CR, PF respectively. In the 281 patients, the results of APTT, FIB, PLT, ACT, CR, and PF ranged from 20.5-300.0 s, 0.28-4.11 g/L, (19.0-387.3)×109/L, 80-514 s, 2.9-74 signal U/min, and 0.1-5.1 respectively. The cut-off values for transfusion were >208, ≤14, and ≤1.3 for ACT, CR, PF respectively. The cut-off values of Sonoclot analysis were within the manufacturer's reference intervals, while they were outside the reference intervals established in this study. The results suggested that the manufacturer's reference intervals were not suitable for Chinese. The reference intervals and cut-off values established in this study will be helpful to Chinese patients. PMID:27465342

  6. Characterization of Tack Strength Based on Cavity-Growth Criterion.

    PubMed

    Takahashi, Kosuke; Yamagata, Yuichiro; Inaba, Kazuaki; Kishimoto, Kikuo; Tomioka, Shiori; Sugizaki, Toshio

    2016-04-12

    The adhesive force generated by a small short-term pressure, called tack, is measured by a probe tack test on pressure-sensitive adhesives (PSAs); the maximum force is evaluated by cavity growth at the interface between the PSA layer and the probe surface. As the PSA layer becomes thinner, it is more difficult to measure the tack with a cylindrical probe because of the uneven contact resulting from misalignment. A spherical probe is preferable to obtain reproducible contact on the PSA layer, but the contact area should be taken into account if the contact pressure affects the tack performance. Tack was measured on PSAs with various thicknesses in different contact areas to clarify their effect. The results showed that a larger contact area on a thinner PSA generated higher adhesive stress with larger strain. It was found that the maximum adhesive stress was not affected by the contact pressure, but it was strongly correlated to the contact radius divided by the PSA thickness. In addition, a video microscope observation showed that, in all of the experimental cases, the adhesive stress always reached the maximum when cavities were generated at the interface between the PSA and probe surface. Therefore, the criterion of cavity growth was introduced for the evaluation of the maximum adhesive stress. As a result, the experimental results, even at different release rates, were in good agreement with the estimation by considering the effect of confining a thin layer. Furthermore, the theoretical estimation indicated the ultimate value, which was not dependent upon the PSA thickness or contact area. It was defined as a material property, referred to as the "ultimate tack strength" of PSAs. PMID:26991212

  7. Working Memory in Children with Learning Disabilities: Rethinking the Criterion of Discrepancy

    ERIC Educational Resources Information Center

    Maehler, Claudia; Schuchardt, Kirsten

    2011-01-01

    The criterion of discrepancy is used to distinguish children with learning disorders from children with intellectual disabilities. The justification of the criterion of discrepancy for the diagnosis of learning disorders relies on the conviction of fundamental differences between children with learning difficulties with versus without discrepancy…

  8. Evidence for the Criterion Validity and Clinical Utility of the Pathological Narcissism Inventory

    ERIC Educational Resources Information Center

    Thomas, Katherine M.; Wright, Aidan G. C.; Lukowitsky, Mark R.; Donnellan, M. Brent; Hopwood, Christopher J.

    2012-01-01

    In this study, the authors evaluated aspects of criterion validity and clinical utility of the grandiosity and vulnerability components of the Pathological Narcissism Inventory (PNI) using two undergraduate samples (N = 299 and 500). Criterion validity was assessed by evaluating the correlations of narcissistic grandiosity and narcissistic…

  9. Replacement Air Group Performance as a Criterion for Naval Aviation Training.

    ERIC Educational Resources Information Center

    Bale, Ronald M.; And Others

    The current criterion for prediction of performance of student naval aviators is the dichotomy of success versus failure in undergraduate flight training. This criterion has enabled the naval air training command to make reasonable estimates of the probability of an applicant or student completing flight training. However, a costly attrition…

  10. On the thermodynamic criterion for detonability of a phase-transforming substance

    NASA Astrophysics Data System (ADS)

    Fowles, G. Richard

    1990-05-01

    The thermodynamic criterion for detonability of a phase-transforming substance derived by Kuznetsov [Sov. Phys. JETP 22, 1047 (1966)] is shown to be an approximation to the more general criterion for detonability, namely, (∂P/∂λ)E,V>0, where E is internal energy, V is volume, and λ is the reaction coordinate measured positive as the reaction proceeds toward equilibrium.

  11. The New DSM-5 Impairment Criterion: A Challenge to Early Autism Spectrum Disorder Diagnosis?

    ERIC Educational Resources Information Center

    Zander, Eric; Bölte, Sven

    2015-01-01

    The possible effect of the DSM-5 impairment criterion on diagnosing autism spectrum disorder (ASD) in young children was examined in 127 children aged 20-47 months with a DSM-IV-TR clinical consensus diagnosis of ASD. The composite score of the Vineland Adaptive Behavior Scales (VABS) served as a proxy for the DSM-5 impairment criterion. When…

  12. A Controlled Evaluation of the Distress Criterion for Binge Eating Disorder

    ERIC Educational Resources Information Center

    Grilo, Carlos M.; White, Marney A.

    2011-01-01

    Objective: Research has examined various aspects of the validity of the research criteria for binge eating disorder (BED) but has yet to evaluate the utility of Criterion C, "marked distress about binge eating." This study examined the significance of the marked distress criterion for BED using 2 complementary comparison groups. Method: A total of…

  13. Characteristics of Criterion-Referenced Instruments: Implications for Materials Selection for the Learning Disabled.

    ERIC Educational Resources Information Center

    Blasi, Joyce F.

    Discussed are characteristics of criterion referenced reading tests for use with learning disabled (LD) children, and analyzed are the Basic Educational Skills Inventory (BESI), the Prescriptive Reading Inventory (PRI), and the Cooper-McGuire Diagnostic Work-Analysis Test (CooperMcGuire). Criterion referenced tests are defined; and problems in…

  14. Criterion Referenced Measurement for One Continuing Education Offering: Pre- and Postoperative Visits by Operating Room Nurses

    ERIC Educational Resources Information Center

    Kneedler, Julie

    1976-01-01

    Criterion referenced measurement is one method which can be utilized to evaluate the learner's achievement of the objectives of continuing education programs and an invaluable mechanism whereby program effectiveness can be evaluated. How to set up an instructional module using a criterion referenced base (subject matter, objectives, test…

  15. 46 CFR 170.173 - Criterion for vessels of unusual proportion and form.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Criterion for vessels of unusual proportion and form... Criterion for vessels of unusual proportion and form. (a) If required by the Coast Guard Marine Safety... the vessels described in § 170.170(d) as having unusual proportion and form, compliance...

  16. Computable criterion for partial entanglement in continuous-variable quantum systems

    SciTech Connect

    Gabriel, Andreas; Huber, Marcus; Radic, Sasa; Hiesmayr, Beatrix C.

    2011-05-15

    A general and computable criterion for k-(in)separability in continuous multipartite quantum systems is presented. The criterion can be experimentally implemented with a finite and comparatively low number of local observables. We discuss in detail how the detection quality can be optimized.

  17. Assessing Fit and Dimensionality in Least Squares Metric Multidimensional Scaling Using Akaike's Information Criterion

    ERIC Educational Resources Information Center

    Ding, Cody S.; Davison, Mark L.

    2010-01-01

    Akaike's information criterion is suggested as a tool for evaluating fit and dimensionality in metric multidimensional scaling that uses least squares methods of estimation. This criterion combines the least squares loss function with the number of estimated parameters. Numerical examples are presented. The results from analyses of both simulation…

  18. An Evaluation of Available Models for Estimating the Reliability and Validity of Criterion Referenced Measures.

    ERIC Educational Resources Information Center

    Oakland, Thomas

    New strategies for evaluation criterion referenced measures (CRM) are discussed. These strategies examine the following issues: (1) the use of normed referenced measures (NRM) as CRM and then estimating the reliability and validity of such measures in terms of variance from an arbitrarily specified criterion score, (2) estimation of the…

  19. The Testing of English as a Second/Foreign Language in the Criterion-Referenced Era.

    ERIC Educational Resources Information Center

    Davidson, Fred

    In the assessment of second/foreign language proficiency, we are entering the era of criterion-referenced assessment as language learning is being recognized as an integrative, multifaceted construct. Norm-referenced measurement (NRM) is compared with criterion-referenced measurement (CRM). CRM is characterized by attention to skill, whereas NRM…

  20. A generalization of the Nyquist stability criterion. [extension to multivariable linear feedback systems

    NASA Technical Reports Server (NTRS)

    Stevens, P. K.

    1981-01-01

    This paper presents a generalization of the Nyquist stability criterion to include general multivariable linear stationary systems subject to linear static and dynamic feedback. At the same time, a unifying proof is given for all known versions of the Nyquist criterion for finite dimensional systems.

  1. Criterion-Referenced and Norm-Referenced Assessments: Compatibility and Complementarity

    ERIC Educational Resources Information Center

    Lok, Beatrice; McNaught, Carmel; Young, Kenneth

    2016-01-01

    The tension between criterion-referenced and norm-referenced assessment is examined in the context of curriculum planning and assessment in outcomes-based approaches to higher education. This paper argues the importance of a criterion-referenced assessment approach once an outcomes-based approach has been adopted. It further discusses the…

  2. A Model for Estimating the Reliability and Validity of Criterion-Referenced Measures.

    ERIC Educational Resources Information Center

    Edmonston, Leon P.; Randall, Robert S.

    A decision model designed to determine the reliability and validity of criterion referenced measures (CRMs) is presented. General procedures which pertain to the model are discussed as to: Measures of relationship, Reliability, Validity (content, criterion-oriented, and construct validation), and Item Analysis. The decision model is presented in…

  3. An Investigation Into the Use of Criterion-Referenced Measurement in Vocational and Technical Training.

    ERIC Educational Resources Information Center

    Day, Gerald F.

    The paper investigates and analyses the current state of the art of criterion-referenced measurement (CRM), with a view to determining its use in training and instructional programs. It presents a reveiw of the literature pertaining to the following aspects: a brief history of CRM; a definition and comparison of criterion-referenced and…

  4. 46 CFR 167.01-8 - Inspection of school ships using gross tonnage criterion.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Inspection of school ships using gross tonnage criterion. 167.01-8 Section 167.01-8 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS General Provisions § 167.01-8 Inspection of school ships using gross tonnage criterion. (a) One of...

  5. 46 CFR 167.01-8 - Inspection of school ships using gross tonnage criterion.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Inspection of school ships using gross tonnage criterion. 167.01-8 Section 167.01-8 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS PUBLIC NAUTICAL SCHOOL SHIPS General Provisions § 167.01-8 Inspection of school ships using gross tonnage criterion. (a) One of...

  6. Evaluation of Regression Models of Balance Calibration Data Using an Empirical Criterion

    NASA Technical Reports Server (NTRS)

    Ulbrich, Norbert; Volden, Thomas R.

    2012-01-01

    An empirical criterion for assessing the significance of individual terms of regression models of wind tunnel strain gage balance outputs is evaluated. The criterion is based on the percent contribution of a regression model term. It considers a term to be significant if its percent contribution exceeds the empirical threshold of 0.05%. The criterion has the advantage that it can easily be computed using the regression coefficients of the gage outputs and the load capacities of the balance. First, a definition of the empirical criterion is provided. Then, it is compared with an alternate statistical criterion that is widely used in regression analysis. Finally, calibration data sets from a variety of balances are used to illustrate the connection between the empirical and the statistical criterion. A review of these results indicated that the empirical criterion seems to be suitable for a crude assessment of the significance of a regression model term as the boundary between a significant and an insignificant term cannot be defined very well. Therefore, regression model term reduction should only be performed by using the more universally applicable statistical criterion.

  7. Laboratory study on new cathodic protection criterion proposed for prestressed concrete

    SciTech Connect

    Wagner, J. Jr.; Funahashi, M.

    1994-12-31

    Bazzoni and Lazzari have proposed a new criterion for the cathodic protection of prestressed concrete. The criterion is based on the use of mixed metal-oxide-activated anodes which exhibit a stable polarized potential over a wide range of current densities when embedded in concrete. The criterion proposes that a ``safe`` anode/structure feeding voltage can be calculated that will both provide corrosion control in the area covered by the anode system and will prevent the steel reinforcement potential reaching values where hydrogen ions can be reduced to hydrogen and the consequent possibility of embrittlement of high strength prestressing members. This paper describes a laboratory study made to examine the validity of the proposed criterion. The results of the study appear to support criterion as both safe and effective for new prestressed concrete structures and possibly for existing structures as well.

  8. Objective Error Criterion for Evaluation of Mapping Accuracy Based on Sensor Time-of-Flight Measurements

    PubMed Central

    Barshan, Billur

    2008-01-01

    An objective error criterion is proposed for evaluating the accuracy of maps of unknown environments acquired by making range measurements with different sensing modalities and processing them with different techniques. The criterion can also be used for the assessment of goodness of fit of curves or shapes fitted to map points. A demonstrative example from ultrasonic mapping is given based on experimentally acquired time-of-flight measurements and compared with a very accurate laser map, considered as absolute reference. The results of the proposed criterion are compared with the Hausdorff metric and the median error criterion results. The error criterion is sufficiently general and flexible that it can be applied to discrete point maps acquired with other mapping techniques and sensing modalities as well.

  9. Generalized Majority Logic Criterion to Analyze the Statistical Strength of S-Boxes

    NASA Astrophysics Data System (ADS)

    Hussain, Iqtadar; Shah, Tariq; Gondal, Muhammad Asif; Mahmood, Hasan

    2012-05-01

    The majority logic criterion is applicable in the evaluation process of substitution boxes used in the advanced encryption standard (AES). The performance of modified or advanced substitution boxes is predicted by processing the results of statistical analysis by the majority logic criteria. In this paper, we use the majority logic criteria to analyze some popular and prevailing substitution boxes used in encryption processes. In particular, the majority logic criterion is applied to AES, affine power affine (APA), Gray, Lui J, residue prime, S8 AES, Skipjack, and Xyi substitution boxes. The majority logic criterion is further extended into a generalized majority logic criterion which has a broader spectrum of analyzing the effectiveness of substitution boxes in image encryption applications. The integral components of the statistical analyses used for the generalized majority logic criterion are derived from results of entropy analysis, contrast analysis, correlation analysis, homogeneity analysis, energy analysis, and mean of absolute deviation (MAD) analysis.

  10. Negative-Margin Criterion for Impact-Response Prediction

    NASA Astrophysics Data System (ADS)

    Anderson, Denton

    2006-01-01

    Some space missions require a nuclear-power source to generate electrical power to meet mission objectives. At present, the nuclear-power source is an assembly of modular heat sources called the general purpose heat source (GPHS) modules. Each module comprises graphite shells designed to protect iridium-alloy clads which serve as the primary containment shells for the radioactive, heat-producing material. In the course of launching the space vehicle to perform its mission the nuclear heat source may be exposed to severe accident environments. One particular environment is a primary impact event where individual GPHS modules impact hard surfaces at speeds in the range of 50 meters per second or more. Tests have shown that some clads may be breached in particularly severe impacts and release a small fraction of their contents. This paper presents an empirical model for predicting essential ingredients for assessing the risk associated with primary impact events. The ingredients include: clad failure probability, release fraction of clad contents, characterization of the released material in terms of particle-size distribution and a means to estimate uncertainty in the prediction process. The empirical model focuses on the deformation of the clads and their capability to withstand deformation without breaching, measured by ductility. The basic criterion used to estimate all ingredients is called ``negative margin''. The procedure for estimating risk factors entails calculation of clad distortion by, e.g. hydrocode simulation, and high-strain-rate ductility of the iridium alloy. Negative margin is a linear combination of distortion and ductility. Regression equations derived from test data are used to calculate the clad failure probability and the fractional activity release as functions of negative margin. The mass-based particle-size distribution is calculated as a function of release fraction. Cumulative uncertainty in this computing process is evaluated using

  11. Variations in Criterion A and PTSD rates in a community sample of women.

    PubMed

    Anders, Samantha L; Frazier, Patricia A; Frankfurt, Sheila B

    2011-03-01

    We assessed PTSD prevalence and symptoms as a function of whether participants' worst lifetime event met Criterion A1 for PTSD (DSM-IV-TR; APA, 2000) and whether the event was directly or indirectly experienced in a community sample of adult women (N=884). Exposure to both non-Criterion A1 and Criterion A1 events was systematically assessed. PTSD was assessed with regard to participants' self-nominated worst event using the PTSD module of the SCID-I/NP (First, Spitzer, Gibbon, & Williams, 1997). There were no differences in PTSD prevalence rates between Criterion A1 and non-A1 events; however, directly experienced worst events were significantly more likely to meet PTSD criteria than were indirectly experienced worst events. Non-Criterion A1 and directly experienced worst events were associated with significantly more PTSD symptoms than were Criterion A1 or indirectly experienced events, respectively. Criterion A2 (experiencing fear, helplessness, or horror) had little effect on PTSD rates. PMID:20888184

  12. An LMI Based Criterion for Global Asymptotic Stability of Discrete-Time State-Delayed Systems with Saturation Nonlinearities

    PubMed Central

    Kokil, Priyanka

    2014-01-01

    A linear matrix inequality (LMI) based criterion for the global asymptotic stability of discrete-time systems with multiple state-delays employing saturation nonlinearities is presented. Numerical examples highlighting the effectiveness of the proposed criterion are given.

  13. A second perspective on the Amann-Schmiedl-Seifert criterion for non-equilibrium in a three-state system

    NASA Astrophysics Data System (ADS)

    Jia, Chen; Chen, Yong

    2015-05-01

    In the work of Amann, Schmiedl and Seifert (2010 J. Chem. Phys. 132 041102), the authors derived a sufficient criterion to identify a non-equilibrium steady state (NESS) in a three-state Markov system based on the coarse-grained information of two-state trajectories. In this paper, we present a mathematical derivation and provide a probabilistic interpretation of the Amann-Schmiedl-Seifert (ASS) criterion. Moreover, the ASS criterion is compared with some other criterions for a NESS.

  14. An experimental verification of a criterion for forming metastable phases in containerless solidification

    NASA Astrophysics Data System (ADS)

    Kuribayashi, K.; Kato, H.; Nagayama, K.; Inatomi, Y.; Kumar, M. S. Vijaya

    2015-04-01

    On the thermodynamic condition for forming a metastable phase from undercooled melt in a containerless state, we had proposed a criterion that crystals will preferentially form if they have a smaller entropy of fusion than the entropy of fusion of equilibrium crystals (Kuribayashi et al., Mater. Sci. Eng., A 449-451, 675 (2007)). This criterion is proposed for being applied to materials that exhibit a faceted interface, such as semiconductors and oxides. However, no experimental data that support this criterion have been obtained. From this point, we used an aerodynamic levitator as a tool for forming metastable phases from undercooled melt and verified the above-mentioned criterion using LnFeO3 (Ln: lanthanide and Y) as the model material. In addition, the condition for double recalescence, which corresponds to forming metastable phases and stable phases, was discussed in terms of competitive 2D isomorphic nucleation of the metastable phase and 3D polymorphic nucleation of the stable phase.

  15. Investigations on reproducing kernel particle method enriched by partition of unity and visibility criterion

    NASA Astrophysics Data System (ADS)

    Zhang, Z. Q.; Zhou, J. X.; Wang, X. M.; Zhang, Y. F.; Zhang, L.

    2004-09-01

    This work introduces a numerical integration technique based on partition of unity (PU) to reproducing kernel particle method (RKPM) and presents an implementation of the visibility criterion for meshfree methods. According to the theory of PU and the inherent features of Gaussian quadrature, the convergence property of the PU integration is studied in the paper. Moreover, the practical approaches to implement the PU integration are presented in different strategies. And a method to carry out visibility criterion is presented to handle the problems with a complex domain. Furthermore, numerical examples have been performed on the h-version and p-like version convergence studies of the PU integration and the validity of visibility criterion. The results demonstrate that PU integration is a feasible and effective numerical integration technique, and RKPM enriched by PU integration and visibility criterion is of more efficiency, versatility and high performance.

  16. Yeh-Stratton Criterion for Stress Concentrations on Fiber-Reinforced Composite Materials

    NASA Technical Reports Server (NTRS)

    Yeh, Hsien-Yang; Richards, W. Lance

    1996-01-01

    This study investigated the Yeh-Stratton Failure Criterion with the stress concentrations on fiber-reinforced composites materials under tensile stresses. The Yeh-Stratton Failure Criterion was developed from the initial yielding of materials based on macromechanics. To investigate this criterion, the influence of the materials anisotropic properties and far field loading on the composite materials with central hole and normal crack were studied. Special emphasis was placed on defining the crack tip stress fields and their applications. The study of Yeh-Stratton criterion for damage zone stress fields on fiber-reinforced composites under tensile loading was compared with several fracture criteria; Tsai-Wu Theory, Hoffman Theory, Fischer Theory, and Cowin Theory. Theoretical predictions from these criteria are examined using experimental results.

  17. A criterion for high-cycle fatigue life and fatigue limit prediction in biaxial loading conditions

    NASA Astrophysics Data System (ADS)

    Pejkowski, Łukasz; Skibicki, Dariusz

    2016-08-01

    This paper presents a criterion for high-cycle fatigue life and fatigue strength estimation under periodic proportional and non-proportional cyclic loading. The criterion is based on the mean and maximum values of the second invariant of the stress deviator. Important elements of the criterion are: function of the non-proportionality of fatigue loading and the materials parameter that expresses the materials sensitivity to non-proportional loading. The methods for the materials parameters determination uses three S-N curves: tension-compression, torsion, and any non-proportional loading proposed. The criterion has been verified using experimental data, and the results are included in the paper. These results should be considered as promising. The paper also includes a proposal for multiaxial fatigue models classification due to the approach for the non-proportionality of loading.

  18. Correction to the Alfven-Lawson criterion for relativistic electron beams

    SciTech Connect

    Dodin, I. Y.; Fisch, N. J.

    2006-10-15

    The Alfven-Lawson criterion for relativistic electron beams is revised. The parameter range is found, in which a stationary beam can carry arbitrarily large current, regardless of its transverse structure.

  19. An experimental verification of a criterion for forming metastable phases in containerless solidification

    SciTech Connect

    Kuribayashi, K.; Inatomi, Y.; Kumar, M. S. Vijaya

    2015-04-21

    On the thermodynamic condition for forming a metastable phase from undercooled melt in a containerless state, we had proposed a criterion that crystals will preferentially form if they have a smaller entropy of fusion than the entropy of fusion of equilibrium crystals (Kuribayashi et al., Mater. Sci. Eng., A 449–451, 675 (2007)). This criterion is proposed for being applied to materials that exhibit a faceted interface, such as semiconductors and oxides. However, no experimental data that support this criterion have been obtained. From this point, we used an aerodynamic levitator as a tool for forming metastable phases from undercooled melt and verified the above-mentioned criterion using LnFeO{sub 3} (Ln: lanthanide and Y) as the model material. In addition, the condition for double recalescence, which corresponds to forming metastable phases and stable phases, was discussed in terms of competitive 2D isomorphic nucleation of the metastable phase and 3D polymorphic nucleation of the stable phase.

  20. 34 CFR 389.30 - What additional selection criterion is used under this program?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... criterion is used under this program? In addition to the criteria in 34 CFR 385.31(c), the Secretary uses... improve the competence of professional and other personnel in the rehabilitation agencies...

  1. 34 CFR 389.30 - What additional selection criterion is used under this program?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... criterion is used under this program? In addition to the criteria in 34 CFR 385.31(c), the Secretary uses... improve the competence of professional and other personnel in the rehabilitation agencies...

  2. The Cognitive Abilities Scale--Second Edition Preschool Form: Studies of Concurrent Criterion-Related, Construct, and Predictive Criterion-Related Validity

    ERIC Educational Resources Information Center

    Swanson, Jennifer R.; Bradley-Johnson, Sharon; Johnson, C. Merle; O'Dell, Anna Rubenaker

    2009-01-01

    Three studies examine the validity of the Preschool Form of the Cognitive Abilities Scale--Second Edition (CAS-2). Significant high concurrent criterion-related validity correlations, corrected for restricted range, are found between the CAS-2 and the Detroit Test of Learning Ability--Primary: Third Edition for 26 three-year-olds (r[subscript c] =…

  3. A novel delay-dependent criterion for delayed neural networks of neutral type

    NASA Astrophysics Data System (ADS)

    Lee, S. M.; Kwon, O. M.; Park, Ju H.

    2010-04-01

    This Letter considers a robust stability analysis method for delayed neural networks of neutral type. By constructing a new Lyapunov functional, a novel delay-dependent criterion for the stability is derived in terms of LMIs (linear matrix inequalities). A less conservative stability criterion is derived by using nonlinear properties of the activation function of the neural networks. Two numerical examples are illustrated to show the effectiveness of the proposed method.

  4. Failure Study of Composite Materials by the Yeh-Stratton Criterion

    NASA Technical Reports Server (NTRS)

    Yeh, Hsien-Yang; Richards, W. Lance

    1997-01-01

    The newly developed Yeh-Stratton (Y-S) Strength Criterion was used to study the failure of composite materials with central holes and normal cracks. To evaluate the interaction parameters for the Y-S failure theory, it is necessary to perform several biaxial loading tests. However, it is indisputable that the inhomogeneous and anisotropic nature of composite materials have made their own contribution to the complication of the biaxial testing problem. To avoid the difficulties of performing many biaxial tests and still consider the effects of the interaction term in the Y-S Criterion, a simple modification of the Y-S Criterion was developed. The preliminary predictions by the modified Y-S Criterion were relatively conservative compared to the testing data. Thus, the modified Y-S Criterion could be used as a design tool. To further understand the composite failure problem, an investigation of the damage zone in front of the crack tip coupled with the Y-S Criterion is imperative.

  5. The interaction of criterion and feedback information in learning a drawing task.

    PubMed

    Newell, K M; Carlton, M J; Antoniou, A

    1990-12-01

    Experiments were designed to examine the influence of criterion and feedback information in the learning of a two-dimensional drawing task. Experiment 1 showed that when the task criterion is well known to the subject, the combined presentation of criterion information and information feedback facilitates the rate of acquisition of the skill but not its overall performance level of achievement. Experiment 2 showed that when the task criterion information is not well known to the subject, presentation of criterion information facilitates both the rate of acquisition and the overall performance level and, furthermore, is essential if configuration information feedback is to be utilized effectively. Experiment 3 showed that it is the combined presentation of criterion and configuration information feedback rather than the isolate presentation of either type of information alone, that facilitates learning and performance. Collectively, the findings from the three experiments suggest an interactive effect of prior knowledge by the learner and type of augmented information in facilitating the acquisition of skill, according to the constraints imposed in the task. The data are consistent with the proposal that the degrees of freedom in the information available to support motor skill learning must match the degrees of freedom to be constraint in the perceptual-motor workspace. PMID:15117661

  6. A Criterion for Brittle Failure of Rocks Using the Theory of Critical Distances

    NASA Astrophysics Data System (ADS)

    Castro, Jorge; Cicero, Sergio; Sagaseta, César

    2016-01-01

    This paper presents a new analytical criterion for brittle failure of rocks and heavily over-consolidated soils. Griffith's model of a randomly oriented defect under a biaxial stress state is used to keep the criterion simple. The Griffith's criterion is improved because the maximum tensile strength is not evaluated at the boundary of the defect but at a certain distance from the boundary, known as half of the critical distance. This fracture criterion is known as the point method, and is part of the theory of critical distances, which is utilised in fracture mechanics. The proposed failure criterion has two parameters: the inherent tensile strength, σ 0, and the ratio of the half-length of the initial crack/flaw to the critical distance, a/ L. These parameters are difficult to measure but they may be correlated with the uniaxial compressive and tensile strengths, σ c and σ t. The proposed criterion is able to reproduce the common range of strength ratios for rocks and heavily overconsolidated soils ( σ c/ σ t = 3-50) and the influence of several microstructural rock properties, such as texture and porosity. Good agreement with laboratory tests reported in the literature is found for tensile and low-confining stresses.

  7. A Mixed-Mode I/II Fracture Criterion and Its Application in Crack Growth Predictions

    NASA Technical Reports Server (NTRS)

    Sutton, Michael A.; Deng, Xiaomin; Ma, Fashang; Newman, James S., Jr.

    1999-01-01

    A crack tip opening displacement (CTOD)-based, mixed mode fracture criterion is developed for predicting the onset and direction of crack growth. The criterion postulates that crack growth occurs in either the Mode I or Mode II direction, depending on whether the maximum in either the opening or the shear component of CTOD, measured at a specified distance behind the crack tip, attains a critical value. For crack growth direction prediction, the proposed CTOD criterion is shown to be equivalent to seven commonly used crack growth criteria under linearly elastic and asymptotic conditions. Under elastic-plastic conditions the CTOD criterion's prediction of the dependence of the crack growth direction on the crack-up mode mixity is in excellent agreement with the Arcan test results. Furthermore, the CTOD criterion correctly predicts the existence of a crack growth transition from mode I to mode II as the mode mixity approaches the mode II loading condition. The proposed CTOD criterion has been implemented in finite element crack growth simulation codes Z1P2DL and FRANC2DL to predict the crack growth paths in (a) a modified Arcan test specimen and fixture made of AL 2024-T34 and (b) a double cantilever beam (DCB) specimen made of AL 7050. A series of crack growth simulations have been carried out for the crack growth tests in the Arcan and DCB specimens and the results further demonstrate the applicability of the mixed mode CTOD fracture criterion crack growth predictions and residual strength analyses for airframe materials.

  8. Defining urine output criterion for acute kidney injury in critically ill patients

    PubMed Central

    Macedo, Etienne; Malhotra, Rakesh; Claure-Del Granado, Rolando; Fedullo, Peter; Mehta, Ravindra L.

    2011-01-01

    Background. The widespread use of RIFLE and AKIN classification systems for acute kidney injury (AKI) diagnosis and staging has established the association between AKI severity and adverse outcomes. However, as a result of the difficulties in measuring and recording the urine output every hour, a few prospective studies have validated the urine output criterion as stated in these classification systems. We assessed hourly urine output in ICU patients using an automated and accurate device to determine if changes in urine flow and volume could be a sensitive marker of AKI. Additionally, we assessed various definitions of oliguria to determine whether measurement of urine output using a fixed 6-h interval that matches nurses’ shifts would be equivalent to the current standard for AKI diagnosis and staging. Methods. Hourly urine output was recorded continuously using a digital monitor in a medical ICU. Serum creatinine measurements were done at least once per 24 h. We assessed changes in urine output by four different definitions of oliguria. Patients with no AKI by either criterion were compared with patients diagnosed exclusively by the urine output criterion, exclusively by serum creatinine criterion and by both criteria. Results. Fifty-five percent of patients had an episode of oliguria during the ICU stay. There was no significant difference assessing urine output every hour or the total urine volume in a 6-h period for the detection of episodes of oliguria. Twenty-one patients (28%) were diagnosed as AKI using the serum creatinine criterion, whereas additional 24 (32%) were identified by the urine output criterion. Conclusions. Episodes of oliguria occur frequently in ICU patients and identify a higher percentage of AKI patients compared to serum creatinine criterion. Alterations in urine flow may be a sensitive marker of renal dysfunction and need to be validated in larger cohorts. PMID:20562094

  9. Criterion learning in rule-based categorization: Simulation of neural mechanism and new data

    PubMed Central

    Helie, Sebastien; Ell, Shawn W.; Filoteo, J. Vincent; Maddox, W. Todd

    2015-01-01

    In perceptual categorization, rule selection consists of selecting one or several stimulus-dimensions to be used to categorize the stimuli (e.g, categorize lines according to their length). Once a rule has been selected, criterion learning consists of defining how stimuli will be grouped using the selected dimension(s) (e.g., if the selected rule is line length, define ‘long’ and ‘short’). Very little is known about the neuroscience of criterion learning, and most existing computational models do not provide a biological mechanism for this process. In this article, we introduce a new model of rule learning called Heterosynaptic Inhibitory Criterion Learning (HICL). HICL includes a biologically-based explanation of criterion learning, and we use new category-learning data to test key aspects of the model. In HICL, rule selective cells in prefrontal cortex modulate stimulus-response associations using pre-synaptic inhibition. Criterion learning is implemented by a new type of heterosynaptic error-driven Hebbian learning at inhibitory synapses that uses feedback to drive cell activation above/below thresholds representing ionic gating mechanisms. The model is used to account for new human categorization data from two experiments showing that: (1) changing rule criterion on a given dimension is easier if irrelevant dimensions are also changing (Experiment 1), and (2) showing that changing the relevant rule dimension and learning a new criterion is more difficult, but also facilitated by a change in the irrelevant dimension (Experiment 2). We conclude with a discussion of some of HICL’s implications for future research on rule learning. PMID:25682349

  10. Responder Status Criterion for Stepped Care Trauma-Focused Cognitive Behavioral Therapy for Young Children

    PubMed Central

    Salloum, Alison; Scheeringa, Michael S.; Cohen, Judith A.; Storch, Eric A.

    2014-01-01

    Background In order to develop Stepped Care Trauma-Focused Cognitive Behavioral Therapy (TF-CBT), a definition of early response/non-response is needed to guide decisions about the need for subsequent treatment. Objective The purpose of this article is to (1) establish criterion for defining an early indicator of response/nonresponse to the first step within Stepped Care TF-CBT, and (2) to explore the preliminary clinical utility of the early response/non-response criterion. Method Data from two studies were used: (1) treatment outcome data from a clinical trial in which 17 young children (ages 3 to 6 years) received therapist-directed CBT for children with PTSS were examined to empirically establish the number of posttraumatic stress symptoms to define early treatment response/non-response; and (2) three case examples with young children in Stepped Care TF-CBT were used to explore the utility of the treatment response criterion. Results For defining the responder status criterion, an algorithm of either 3 or fewer PTSS on a clinician-rated measure or being below the clinical cutoff score on a parent-rated measure of childhood PTSS, and being rated as improved, much improved or free of symptoms functioned well for determining whether or not to step up to more intensive treatment. Case examples demonstrated how the criterion were used to guide subsequent treatment, and that responder status criterion after Step One may or may not be aligned with parent preference. Conclusion Although further investigation is needed, the responder status criterion for young children used after Step One of Stepped Care TF-CBT appears promising. PMID:25663796

  11. Effective Fatigue Stress and Criterion for High-Cycle Multi-axial Fatigue

    NASA Astrophysics Data System (ADS)

    Cai, Xiaojing; Xu, Jinquan

    2015-01-01

    Multi-axial fatigue criterion corresponding to the limiting condition of complicated multi-axial stress state is very important in application. Stresses and deformations are usually elastic if cyclic loadings are near to the limiting condition. A definition of effective fatigue stress has been proposed. Adopting the effective fatigue stress, a multi-axial fatigue criterion has been proposed by considering the equivalence of multi-axial stresses to a uni-axial problem. To clarify the fatigue criterion for a uni-axial problem with arbitrary mean stress, a quantitative relationship between fatigue limit and mean stress has also been proposed and examined. To verify the multi-axial fatigue criterion, examinations have been carried out for the cases of pure shear, shear and axial, and two-axial fatigue by experimental results. It is found that the criterion agrees well with experimental results, even for the cases with various multi-axial mean stresses and phase differences. It is also found that the shear fatigue limit is not an independent material property in common metals.

  12. An analytic expression for the sheath criterion in magnetized plasmas with multi-charged ion species

    SciTech Connect

    Hatami, M. M.

    2015-04-15

    The generalized Bohm criterion in magnetized multi-component plasmas consisting of multi-charged positive and negative ion species and electrons is analytically investigated by using the hydrodynamic model. It is assumed that the electrons and negative ion density distributions are the Boltzmann distribution with different temperatures and the positive ions enter into the sheath region obliquely. Our results show that the positive and negative ion temperatures, the orientation of the applied magnetic field and the charge number of positive and negative ions strongly affect the Bohm criterion in these multi-component plasmas. To determine the validity of our derived generalized Bohm criterion, it reduced to some familiar physical condition and it is shown that monotonically reduction of the positive ion density distribution leading to the sheath formation occurs only when entrance velocity of ion into the sheath satisfies the obtained Bohm criterion. Also, as a practical application of the obtained Bohm criterion, effects of the ionic temperature and concentration as well as magnetic field on the behavior of the charged particle density distributions and so the sheath thickness of a magnetized plasma consisting of electrons and singly charged positive and negative ion species are studied numerically.

  13. Fulfillment of the kinetic Bohm criterion in a quasineutral particle-in-cell model

    NASA Astrophysics Data System (ADS)

    Ahedo, Eduardo; Santos, Robert; Parra, Félix I.

    2010-07-01

    Quasineutral particle-in-cell models of ions must fulfill the kinetic Bohm criterion, in its inequality form, at the domain boundary in order to match correctly with solutions of the Debye sheaths tied to the walls. The simple, fluid form of the Bohm criterion is shown to be a bad approximation of the exact, kinetic form when the ion velocity distribution function has a significant dispersion and involves different charge numbers. The fulfillment of the Bohm criterion is measured by a weighting algorithm at the boundary, but linear weighting algorithms have difficulties to reproduce the nonlinear behavior around the sheath edge. A surface weighting algorithm with an extended temporal weighting is proposed and shown to behave better than the standard volumetric weighting. Still, this must be supplemented by a forcing algorithm of the kinetic Bohm criterion. This postulates a small potential fall in a supplementary, thin, transition layer. The electron-wall interaction is shown to be of little relevance in the fulfillment of the Bohm criterion.

  14. Quality criterion to optimize separations in capillary electrophoresis: Application to the analysis of harmala alkaloids.

    PubMed

    Tascon, Marcos; Benavente, Fernando; Castells, Cecilia B; Gagliardi, Leonardo G

    2016-08-19

    In capillary electrophoresis (CE), resolution (Rs) and selectivity (α) are criteria often used in practice to optimize separations. Nevertheless, when these and other proposed parameters are considered as an elementary criterion for optimization by mathematical maximization, certain issues and inconsistencies appear. In the present work we analyzed the pros and cons of using these parameters as elementary criteria for mathematical optimization of capillary electrophoretic separations. We characterized the requirements of an ideal criterion to qualify separations within the framework of mathematical optimizations and, accordingly, propose: -1- a new elementary criterion (t') and -2- a method to extend this elementary criterion to compose a global function that simultaneously qualifies many different aspects, also called multicriteria optimization function (MCOF). In order to demonstrate this new concept, we employed a group of six alkaloids with closely related structures (harmine, harmaline, harmol, harmalol, harmane and norharmane). On the basis of this system, we present a critical comparison between the new optimization criterion t' and the former elementary criteria. Finally, aimed at validating the proposed methods, we composed an MCOF in which the capillary-electrophoretic separation of the six model compounds is mathematically optimized as a function of pH as the unique variable. Experimental results subsequently confirmed the accuracy of the model. PMID:27443250

  15. An analytic expression for the sheath criterion in magnetized plasmas with multi-charged ion species

    NASA Astrophysics Data System (ADS)

    Hatami, M. M.

    2015-04-01

    The generalized Bohm criterion in magnetized multi-component plasmas consisting of multi-charged positive and negative ion species and electrons is analytically investigated by using the hydrodynamic model. It is assumed that the electrons and negative ion density distributions are the Boltzmann distribution with different temperatures and the positive ions enter into the sheath region obliquely. Our results show that the positive and negative ion temperatures, the orientation of the applied magnetic field and the charge number of positive and negative ions strongly affect the Bohm criterion in these multi-component plasmas. To determine the validity of our derived generalized Bohm criterion, it reduced to some familiar physical condition and it is shown that monotonically reduction of the positive ion density distribution leading to the sheath formation occurs only when entrance velocity of ion into the sheath satisfies the obtained Bohm criterion. Also, as a practical application of the obtained Bohm criterion, effects of the ionic temperature and concentration as well as magnetic field on the behavior of the charged particle density distributions and so the sheath thickness of a magnetized plasma consisting of electrons and singly charged positive and negative ion species are studied numerically.

  16. Diagnosing criterion-level effects on memory: what aspects of memory are enhanced by repeated retrieval?

    PubMed

    Vaughn, Kalif E; Rawson, Katherine A

    2011-09-01

    Previous research has shown that increasing the criterion level (i.e., the number of times an item must be correctly retrieved during practice) improves subsequent memory, but which specific components of memory does increased criterion level enhance? In two experiments, we examined the extent to which the criterion level affects associative memory, target memory, and cue memory. Participants studied Lithuanian-English word pairs via cued recall with restudy until items were correctly recalled one to five times. In Experiment 1, participants took one of four recall tests and one of three recognition tests after a 2-day delay. In Experiment 2, participants took only recognition tests after a 1-week delay. In both experiments, increasing the criterion level enhanced associative memory, as indicated by enhanced performance on forward and backward cued-recall tests and on tests of associative recognition. An increased criterion level also improved target memory, as indicated by enhanced free recall and recognition of targets, and improved cue memory, as indicated by enhanced free recall and recognition of cues. PMID:21813798

  17. A Review of the CTOA/CTOD Fracture Criterion: Why it Works

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.; James, M. A.

    2001-01-01

    The CTOA/CTOD fracture criterion is one of the oldest fracture criteria applied to fracture of metallic materials with cracks. During the past two decades, the use of elastic-plastic finite-element analyses to simulate fracture of laboratory specimens and structural components using the CTOA criterion has expanded rapidly. But the early applications were restricted to two-dimensional analyses, assuming either plane-stress or plane-strain behavior, which lead to generally non-constant values of CTOA, especially in the early stages crack extension. Later, the non-constant CTOA values were traced to inappropriate state-of-stress (or constraint) assumptions in the crack-front region and severe crack tunneling in thin-sheet materials. More recently, the CTOA fracture criterion has been used with three-dimensional analyses to study constraint effects, crack tunneling, and the fracture process. The constant CTOA criterion (from crack initiation to failure) has been successfully applied to numerous structural applications, such as aircraft fuselages and pipelines. But why does the "constant CTOA" fracture criterion work so well? This paper reviews the results from several studies, discusses the issues of why CTOA works, and discusses its limitations.

  18. A model to examine the validity of the 6-month abstinence criterion for liver transplantation.

    PubMed

    Yates, W R; Martin, M; LaBrecque, D; Hillebrand, D; Voigt, M; Pfab, D

    1998-04-01

    Six months of abstinence from alcohol is a commonly used criterion for liver transplantation eligibility for patients with alcoholic cirrhosis. There is limited evidence to document the validity of this criterion with regard to risk of alcoholism relapse. Ninety-one patients with alcoholic cirrhosis were interviewed for relapse risk using the High Risk Alcoholism Relapse (HRAR) Scale. The HRAR model can be used to predict relapse risk independent of duration of sobriety and therefore can be used to examine the validity of the 6 months of abstinence criteria in this clinical population. The two methods demonstrated poor to fair agreement. Agreement was highest with a cutoff allowing a 5% 6-month relapse risk when 79% agreement (c = 0.56) was demonstrated between the two methods. Using the 6-month abstinence criterion alone disallows a significant number of candidates who have a low relapse risk based on their HRAR score. The validity of the 6-month abstinence criterion is supported somewhat by comparison with the HRAR model. However, use of the 6-month abstinence criterion alone forces a significant number of patients with a low relapse risk by HRAR to wait for transplant listing. A relapse risk model based on an estimate of alcoholism severity in addition to duration of sobriety may more accurately select patients who are most likely to benefit from liver transplantation. PMID:9581661

  19. New Criterion for Evaluating the Peak Shear Strength of Rock Joints Under Different Contact States

    NASA Astrophysics Data System (ADS)

    Tang, Zhi Cheng; Wong, Louis Ngai Yuen

    2016-04-01

    In practice, the peak shear strength of rock joints is not dictated only by the surface roughness, but also the degree of matching between the joint surfaces. The latter is due to alteration/dislocation caused by external factors, such as the vibration due to nearby blasting, excavation or earthquake. In the present study, the peak shear strengths of rock joints under different contact states are investigated by direct shear test using artificial rock joints. The rock joints under different contact states are modeled by imposing varying magnitude of horizontal dislocation along the shear direction between the upper and lower rock blocks. The peak shear strength was found to decrease with increasing dislocation. A new empirical shear strength criterion is put forward to capture the peak shear strength of un-matching rock joints as an extension of a previously published peak shear strength criterion for matching rock joints by the first author and his co-workers. In the present proposed criterion, a new joint contact state coefficient, which is a function of the normalized dislocation and the quantified three-dimensional roughness metric of joint surface, is proposed. The good agreement between calculated values and test results indicates that the proposed criterion is capable of estimating the peak shear strength of rock joints under different contact states. The proposed criterion is expressed in a quantitative way and the required parameters can be easily determined in the laboratory.

  20. Fulfillment of the kinetic Bohm criterion in a quasineutral particle-in-cell model

    SciTech Connect

    Ahedo, Eduardo; Santos, Robert; Parra, Felix I.

    2010-07-15

    Quasineutral particle-in-cell models of ions must fulfill the kinetic Bohm criterion, in its inequality form, at the domain boundary in order to match correctly with solutions of the Debye sheaths tied to the walls. The simple, fluid form of the Bohm criterion is shown to be a bad approximation of the exact, kinetic form when the ion velocity distribution function has a significant dispersion and involves different charge numbers. The fulfillment of the Bohm criterion is measured by a weighting algorithm at the boundary, but linear weighting algorithms have difficulties to reproduce the nonlinear behavior around the sheath edge. A surface weighting algorithm with an extended temporal weighting is proposed and shown to behave better than the standard volumetric weighting. Still, this must be supplemented by a forcing algorithm of the kinetic Bohm criterion. This postulates a small potential fall in a supplementary, thin, transition layer. The electron-wall interaction is shown to be of little relevance in the fulfillment of the Bohm criterion.

  1. A new criterion of photostimulated luminescence (PSL) method to detect irradiated traditional Chinese medicinal herbs

    NASA Astrophysics Data System (ADS)

    Zhang, Liwen; Lin, Tong; Jiang, Yingqiao; Bi, Fujun

    2013-11-01

    This work used a new criterion to analyze 162 varieties (222 batches) of traditional Chinese medicinal herbs based on the European Standard EN 13751 (2009. Foodstuffs—Detection of Irradiated Food Using Photostimulated Luminescence. European Committee for Standardization, Brussels, Belgium). The characteristics of PSL signals are described, and a new criterion is established. Compared to EN 13751, the new criterion uses clearer definition to evaluate instead of the ambiguous descriptions in EN Standard, such as "much greater than" and "within the same order of magnitude". Moreover, the accuracy of the new criterion is as good as or better than EN Standard in regard to classifying irradiated and non-irradiated traditional Chinese medicinal herbs. It can help to avoid false positive result when a non-irradiated herb got a screening PSL measurement above 5000 counts/60 s. This new criterion of photostimulated luminescence method can be applied to identify the irradiation status of traditional Chinese medicinal herbs, even if the medicinal herbs were irradiated at a low dose (0.3 kGy) or stored in the dark at room temperature for 24 months after the irradiation treatment.

  2. A new multiobjective performance criterion used in PID tuning optimization algorithms.

    PubMed

    Sahib, Mouayad A; Ahmed, Bestoun S

    2016-01-01

    In PID controller design, an optimization algorithm is commonly employed to search for the optimal controller parameters. The optimization algorithm is based on a specific performance criterion which is defined by an objective or cost function. To this end, different objective functions have been proposed in the literature to optimize the response of the controlled system. These functions include numerous weighted time and frequency domain variables. However, for an optimum desired response it is difficult to select the appropriate objective function or identify the best weight values required to optimize the PID controller design. This paper presents a new time domain performance criterion based on the multiobjective Pareto front solutions. The proposed objective function is tested in the PID controller design for an automatic voltage regulator system (AVR) application using particle swarm optimization algorithm. Simulation results show that the proposed performance criterion can highly improve the PID tuning optimization in comparison with traditional objective functions. PMID:26843978

  3. One-dimensional flow model for coal-gas outbursts and initiation criterion

    NASA Astrophysics Data System (ADS)

    Shanbing, Yu

    1992-11-01

    This paper discribes a one-dimensional flow model to explain the basic mechanism of coal-gas outbursts. A break-start criterion of coal, as the elementary outburst criterion, is given approximately. In this ideal model, the tectonic pressure before excavation, as a load on coal body, affects the break-start and then the flow field. The flow field is decoupled with the stress field, so that the gas seepage through unbroken coal body, break-start and consequent two-phase flow, and pure gas flow can be analysed independently of the stress field. The tunnelling, an external disturbance that makes the seepage intensify relatively, is an essential factor for initiating outburst. Under steady tunnelling, seepage ought to tend to be steadily progressive. From its asymptotic solution initiation criterion is obtained. This is described by three conditions, possibility condition —tectonic pressure condition, incubation condition—tunnelling or gas condition and triggering condition —seepage velocity condition.

  4. Failure Criterion For Isotropic Time Dependent Materials Which Accounts for Multi-Axial Loading

    NASA Technical Reports Server (NTRS)

    Richardson, D. E.; Anderson, G. L.; Macon, D. J.

    2003-01-01

    The Space Shuttle's Reusable Solid Rocket Motor (RSRM) nozzle program has recently conducted testing to characterize the effects of multi-axial loading, temperature and time on the failure characteristics of TIGA321, EA913NA, EA946 (three filled epoxy adhesives). From the test data a "Multi-Axial, Temperature, and Time Dependent" or MATT failure criterion was developed. It is shown that this criterion simplifies, for constant load and constant load rate conditions, into a form that can be easily used for stress analysis. Failure for TIGA321 and EA913NA are characterized below their glass transition temperature. Failure for EA946 is characterized for conditions that pass through its glass transition. The MATT failure criterion is shown to be accurate for a wide range of conditions for these adhesives.

  5. Probability cueing influences miss rate and decision criterion in visual searches

    PubMed Central

    Ishibashi, Kazuya; Kita, Shinichi

    2014-01-01

    In visual search tasks, the ratio of target-present to target-absent trials has an important effect on miss rates. The low prevalence effect indicates that we are more likely to miss a target when it occurs rarely rather than frequently. In this study, we examined whether probability cueing modulates the miss rate and the observer's criterion. The results indicated that probability cueing affects miss rates, the average observer's criterion, and reaction time for target-absent trials. These results clearly demonstrate that probability cueing modulates two parameters (i.e., the decision criterion and the quitting threshold) and produces a low prevalence effect. Taken together, the current study and previous studies suggest that the miss rate is not just affected by global prevalence; it is also affected by probability cueing. PMID:25469223

  6. A new multiobjective performance criterion used in PID tuning optimization algorithms

    PubMed Central

    Sahib, Mouayad A.; Ahmed, Bestoun S.

    2015-01-01

    In PID controller design, an optimization algorithm is commonly employed to search for the optimal controller parameters. The optimization algorithm is based on a specific performance criterion which is defined by an objective or cost function. To this end, different objective functions have been proposed in the literature to optimize the response of the controlled system. These functions include numerous weighted time and frequency domain variables. However, for an optimum desired response it is difficult to select the appropriate objective function or identify the best weight values required to optimize the PID controller design. This paper presents a new time domain performance criterion based on the multiobjective Pareto front solutions. The proposed objective function is tested in the PID controller design for an automatic voltage regulator system (AVR) application using particle swarm optimization algorithm. Simulation results show that the proposed performance criterion can highly improve the PID tuning optimization in comparison with traditional objective functions. PMID:26843978

  7. Separability Criterion for Arbitrary Multipartite Pure State Based on the Rank of Reduced Density Matrix

    NASA Astrophysics Data System (ADS)

    Zhao, Chao; Yang, Guo-wu; Li, Xiao-yu

    2016-09-01

    Nowadays, there are plenty of separability criteria which are used to detect entanglement. Many of them are limited to apply for some cases. In this paper, we propose a separability criterion for arbitrary multipartite pure state which is based on the rank of reduced density matrix. It is proved that the rank of reduced density matrices of a multipartite state is closely related to entanglement. In fact it can be used to characterize entanglement. Our separability criterion is a necessary and sufficient condition for detecting entanglement. Furthermore, it is able to help us find the completely separable form of a multipartite pure state according to some explicit examples. Finally it demonstrates that our method are more suitable for some specific case. Our separability criterion are simple to understand and it is operational.

  8. Mesoscopic analysis of Gibbs' criterion for sessile nanodroplets on trapezoidal substrates.

    PubMed

    Dutka, F; Napiórkowski, M; Dietrich, S

    2012-02-14

    By taking into account precursor films accompanying nanodroplets on trapezoidal substrates we show that on a mesoscopic level of description one does not observe the phenomenon of liquid-gas-substrate contact line pinning at substrate edges. This phenomenon is present in a macroscopic description and leads to non-unique contact angles which can take values within a range determined by the so-called Gibbs' criterion. Upon increasing the volume of the nanodroplet the apparent contact angle evaluated within the mesoscopic approach changes continuously between two limiting values fulfilling Gibbs' criterion, while the contact line moves smoothly across the edge of the trapezoidal substrate. The spatial extent of the range of positions of the contact line, corresponding to the variations of the contact angle between the values given by Gibbs' criterion, is of the order of ten fluid particle diameters. PMID:22360210

  9. Separability Criterion for Arbitrary Multipartite Pure State Based on the Rank of Reduced Density Matrix

    NASA Astrophysics Data System (ADS)

    Zhao, Chao; Yang, Guo-wu; Li, Xiao-yu

    2016-04-01

    Nowadays, there are plenty of separability criteria which are used to detect entanglement. Many of them are limited to apply for some cases. In this paper, we propose a separability criterion for arbitrary multipartite pure state which is based on the rank of reduced density matrix. It is proved that the rank of reduced density matrices of a multipartite state is closely related to entanglement. In fact it can be used to characterize entanglement. Our separability criterion is a necessary and sufficient condition for detecting entanglement. Furthermore, it is able to help us find the completely separable form of a multipartite pure state according to some explicit examples. Finally it demonstrates that our method are more suitable for some specific case. Our separability criterion are simple to understand and it is operational.

  10. Criterion for DNA melting in the mean-field modified self-consistent phonon theory

    NASA Astrophysics Data System (ADS)

    Feng, Y.; Prohofsky, E. W.

    1991-04-01

    We have examined the validity of the first-order-perturbation method in calculating eigenfunctions and the criterion for helix melting of mean-field polymers in the modified self-consistent phonon approach (MSPA) theory. It is found that the instability in the self-consistent solution is due to the breakdown of the first-order perturbation. The instability as a criterion for helix melting is therefore techniquely inappropriate. However, the breakdown of the perturbation is due to facts that are directly related to the onset of softening. Previously predicted melting temperatures for various sequence DNA polymers may still represent good estimates to the actual melting temperatures. An alternative criterion is required to define the melting temperature of the polymer DNA double helix in the MSPA theory.