Mercier criterion modified by kinetic effects
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.
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.
EdF`s Mercier on the biggest maintenance program in the world
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.
Generalized energy failure criterion.
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
Generalized energy failure criterion
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
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.
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.
Probabilistic Threshold Criterion
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.
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.
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.
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
Generalized melting criterion for amorphization
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.
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.
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…
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…
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…
Extended equal area criterion revisited
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.
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.
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…
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.
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;
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.
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.
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.
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.
Resilience as a universal criterion of health.
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
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.
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…
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.
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…
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…
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.…
The definition and criterion of death.
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
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…
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)
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
Stochastic Games with Average Payoff Criterion
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.
Regularization Parameter Selections via Generalized Information Criterion
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
On the hodological criterion for homology.
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
On the hodological criterion for homology
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
A Rosenzweig-MacArthur (1963) Criterion for the Chemostat
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
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).
Beating the Stoner criterion using molecular interfaces.
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
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.
Generalized Bohm Criterion for Electronegative Complex Plasma
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.
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.…
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.
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
A universal fracture criterion for high-strength materials
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.
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.
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.
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.
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.
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.
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.
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.
A stochastic T cell response criterion
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
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…
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…
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…
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.
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…
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.
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.
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
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.
On the reduction criterion for random quantum states
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.
Energy Criterion for the Spectral Stability of Discrete Breathers.
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
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)
On the risk criterion and the index of risk
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.
GRAVITATIONAL FRAGMENTATION IN GALAXY MERGERS: A STABILITY CRITERION
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.
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.
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.
Criterion buys Akzo`s naphtha reforming catalysts business
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.
VIOLATION OF RICHARDSON'S CRITERION VIA INTRODUCTION OF A MAGNETIC FIELD
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.
An improved failure criterion for biological and engineered staggered composites.
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
Dubious decision evidence and criterion flexibility in recognition memory
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
A new tracer-density criterion for heterogeneous porous media
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.
The role of word choice and criterion on intentional memory.
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
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.
Criticality and quenched disorder: Harris criterion versus rare regions.
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
Bohm's criterion in a collisional magnetized plasma with thermal ions
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.
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.
A path-tracking criterion for an LHD articulated vehicle
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.
A New Biomechanically-Based Criterion for Lateral Skull Fracture
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
An improved failure criterion for biological and engineered staggered composites
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
PTSD and Sexual Orientation: An Examination of Criterion A1 and Non-Criterion A1 Events
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
Nonequilibrium Gibbs' criterion for completely wetting volatile liquids.
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
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.
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…
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…
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…
Application of Weibull Criterion to failure prediction in compsites
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.
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…
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…
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.
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…
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…
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…
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…
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.
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…
Validity criterion for the Born approximation convergence in microscopy imaging.
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
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…
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.…
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…
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…
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…
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…
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…
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…
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…
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…
Prestimulus alpha power influences response criterion in a detection task.
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
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…
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,…
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…
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…
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.
Some properties of the computable cross-norm criterion for separability
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.
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.
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.
On thermonuclear ignition criterion at the National Ignition Facility
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.
Criterion-related validity of the Arabic Children's Depression Inventory.
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
Criterion validity of manual assessment of spinal stiffness.
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
Signal detection with criterion noise: Applications to recognition memory
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
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.
A selection criterion for patterns in reaction–diffusion systems
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
Criterion validation of a stress measure: the Stress Overload Scale.
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
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.
ABET Criterion 3.f: how much curriculum content is enough?
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
On the sampling criterion for structural radiation in fluid.
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
Discrete Lange-Newell criterion for dissipative systems.
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
Forecastability as a Design Criterion in Wind Resource Assessment: Preprint
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.
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.
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
Free-surface stability criterion as affected by velocity distribution
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
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.
Thermoeconomic analysis: A criterion for the selection of cogeneration systems
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.
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.
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.
On the feature selection criterion based on an approximation of multidimensional mutual information.
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
Satisfying the Einstein–Podolsky–Rosen criterion with massive particles
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
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
Nonextensive statistics and the sheath criterion in collisional plasmas
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.
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.
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.
Effective Q criterion for disk stability in an external potential
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.
Satisfying the Einstein-Podolsky-Rosen criterion with massive particles.
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
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.
Refocusing criterion via sparsity measurements in digital holography.
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
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.
The limits of the Bohm criterion in collisional plasmas
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.
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.
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.
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.
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.
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…
Criterion Related Validity of Karate Specific Aerobic Test (KSAT)
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
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
Criterion and incremental validity of the emotion regulation questionnaire.
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
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.
Criterion and incremental validity of the emotion regulation questionnaire
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
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.
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.
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.
Should cognitive deficit be a diagnostic criterion for schizophrenia?
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
Decision processes in recognition memory: criterion shifts and the list-strength paradigm.
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
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.
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.
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.
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.
SALT DAMAGE CRITERION PROOF-OF-CONCEPT RESEARCH
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.
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.
Robust Deep Network with Maximum Correntropy Criterion for Seizure Detection
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
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.
A criterion measurement model for health behavior change.
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
A novel SURE-based criterion for parametric PSF estimation.
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
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.
General criterion for the entanglement of two indistinguishable particles
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.
Robust deep network with maximum correntropy criterion for seizure detection.
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
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.
An improved criterion for new particle formation in diverse environments
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.
Establishment of reference intervals and transfusion criterion for Sonoclot analysis.
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
Determining the Bohm criterion in plasmas with two ion species
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.
Characterization of Tack Strength Based on Cavity-Growth Criterion.
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
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…
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...
Computable criterion for partial entanglement in continuous-variable quantum systems
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.
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…
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…
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…
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.
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…
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…
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…
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…
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.
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…
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…
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…
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.
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...
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...
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…
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…
Laboratory study on new cathodic protection criterion proposed for prestressed concrete
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.
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.
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.
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
Variations in Criterion A and PTSD rates in a community sample of women.
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
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.
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.
Correction to the Alfven-Lawson criterion for relativistic electron beams
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.
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.
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.
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.
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.
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.
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...
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...
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] =…
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.
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.
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.
The interaction of criterion and feedback information in learning a drawing task.
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
Defining urine output criterion for acute kidney injury in critically ill patients
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
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.
Criterion learning in rule-based categorization: Simulation of neural mechanism and new data
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
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
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.
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
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.
An analytic expression for the sheath criterion in magnetized plasmas with multi-charged ion species
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.
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.
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
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.
Fulfillment of the kinetic Bohm criterion in a quasineutral particle-in-cell model
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.
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.
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.
A model to examine the validity of the 6-month abstinence criterion for liver transplantation.
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
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.
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.
Probability cueing influences miss rate and decision criterion in visual searches
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
A new multiobjective performance criterion used in PID tuning optimization algorithms
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
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.
A new multiobjective performance criterion used in PID tuning optimization algorithms.
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
NASA Technical Reports Server (NTRS)
Segenreich, S. A.; Mcintosh, S. C., Jr.
1975-01-01
A rigorous optimality criterion is derived and a hybrid weight-reduction algorithm developed for the weight minimization of lifting surfaces with a constraint on flutter speed. The weight-reduction algorithm incorporates a simple recursion formula derived from the optimality criterion. Monotonic weight reduction is accomplished by dynamically adjusting a parameter in the recursion formula so as to achieve a predetermined weight decrease. The algorithm thus combines the simplicity of optimality-criterion methods with the convergence characteristics of mathematical-programming methods. The imposition of the flutter constraint is simplified by forcing to zero the imaginary part of the flutter eigenvalue, with the airspeed fixed. Four examples are discussed. The results suggest that significant improvements in efficiency are possible, in comparison with techniques based purely on mathematical programming.
Mesoscopic analysis of Gibbs' criterion for sessile nanodroplets on trapezoidal substrates.
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
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.
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.
Vaughn, Kalif E; Dunlosky, John; Rawson, Katherine A
2016-08-01
Retrieval practice improves memory for many kinds of materials, and numerous factors moderate the benefits of retrieval practice, including the amount of successful retrieval practice (referred to as the learning criterion). In general, the benefits of retrieval practice are greater with more than with less successful retrieval practice; however, learning items to a higher (vs. lower) criterion requires more time and effort. If students plan on relearning material in a subsequent study session, does the benefit of learning to a higher criterion during an initial session persist? In Session 1, participants studied and successfully recalled Swahili-English word pairs one, two, three, four, five, six, or seven times. In subsequent sessions, all of the pairs were relearned to a criterion of one correct recall at one-week intervals across four or five successive relearning sessions. Experiments 1 and 2 revealed that the substantial benefits of learning to a higher initial criterion during the first session do not persist across relearning sessions. This relearning-override effect was also demonstrated in Experiment 2 after a one-month retention interval. The implications of relearning-override effects are important for theory and for education. For theories of test-enhanced learning, they support the predictions of one theory and appear inconsistent with the predictions of another. For education, if relearning is to occur, using extra time to learn to a higher initial learning criterion is not efficient. Instead, students should devote their time to subsequent spaced relearning sessions, which produce substantial gains in recall performance. PMID:27027887
Childhood trauma and personality disorder criterion counts: a co-twin control analysis.
Berenz, Erin C; Amstadter, Ananda B; Aggen, Steven H; Knudsen, Gun Peggy; Reichborn-Kjennerud, Ted; Gardner, Charles O; Kendler, Kenneth S
2013-11-01
Correlational studies consistently report relationships between childhood trauma (CT) and most personality disorder (PD) criteria and diagnoses. However, it is not clear whether CT is directly related to PDs or whether common familial factors (i.e., shared environment and/or genetic factors) better account for that relationship. The current study used a cotwin control design to examine support for a direct effect of CT on PD criterion counts. Participants were from the Norwegian Twin Registry (N = 2,780), including a subset (n = 898) of twin pairs (449 pairs, 45% monozygotic [MZ]) discordant for CT meeting DSM-IV Posttraumatic Stress Disorder Criterion A. All participants completed the Norwegian version of the Structured Interview for DSM-IV Personality. Significant associations between CT and all PD criterion counts were detected in the general sample; however, the magnitude of observed effects was small, with CT accounting for no more than approximately 1% of variance in PD criterion counts. A significant, yet modest, interactive effect was detected for sex and CT on Schizoid and Schizotypal PD criterion counts, with CT being related to these disorders among women but not men. After common familial factors were accounted for in the discordant twin sample, CT was significantly related to Borderline and Antisocial PD criterion counts, but no other disorders; however, the magnitude of observed effects was quite modest (r2 = .006 for both outcomes), indicating that the small effect observed in the full sample is likely better accounted for by common genetic and/or environmental factors. CT does not appear to be a key factor in PD etiology. PMID:24364608
An improved watershed image segmentation algorithm combining with a new entropy evaluation criterion
NASA Astrophysics Data System (ADS)
Deng, Tingquan; Li, Yanchao
2013-03-01
An improved watershed image segmentation algorithm is proposed to solve the problem of over-segmentation by classical watershed algorithm. The new algorithm combines region growing with classical watershed algorithm. The key to region growing lies in choosing a growing threshold to reach a desired result of image segmentation. An entropy evaluation criterion is constructed to determine the optimal threshold. Considering the entropy evaluation criterion as an objective function, the particle swarm optimization algorithm is employed to search global optimization of the objective function. Experimental results show that this new algorithm can solve the problem of over-segmentation effectively.
NASA Technical Reports Server (NTRS)
Tennyson, R. C.; Nanyaro, A. P.; Wharram, G. E.
1980-01-01
A comparative failure analysis is presented based on the application of quadratic and cubic forms of the tensor polynomial lamina strength criterion to various composite structural configurations in a plane stress state. Failure loads have been predicted for off-angle laminates under simple loading conditions and for symmetric-balanced laminates subject to varying degrees of biaxial tension, including configurations subject to multimode failures. Some experimental data are also provided to support these calculations. From these results, the necessity of employing a cubic strength criterion to accurately predict the failure of composite laminae is demonstrated.
Validity criterion of the radiative Fourier law for an absorbing and scattering medium.
Gomart, Hector; Taine, Jean
2011-02-01
For radiative heat transfer applications, in particular in homogenized phases of porous media, an exhaustive and accurate validity criterion of the radiative Fourier law, depending only on the logarithmic derivative of the temperature field and an effective absorption coefficient, accounting for possible multiple scattering phenomena, has been established for a semitransparent medium. This effective absorption coefficient is expressed as a function of the absorption coefficient, the albedo, and the scattering asymmetry parameter. The criterion can be applied to semitransparent media that do not follow Beer's laws related to extinction, absorption, and scattering. PMID:21405835
Ponte, M.A. de; Mizrahi, S.S.; Moussa, M.H.Y.
2009-11-15
We propose a method to compute the entanglement degree E of bipartite systems having dimension 2 x 2 and demonstrate that the partial transposition of density matrix, the Peres criterion, arise as a consequence of our method. Differently from other existing measures of entanglement, the one presented here makes possible the derivation of a criterion to verify if an arbitrary bipartite entanglement will suffers sudden death (SD) based only on the initial-state parameters. Our method also makes possible to characterize the SD as a dynamical quantum phase transition, with order parameter E, having a universal critical exponent -1/2.
Analyses of S-Box in Image Encryption Applications Based on Fuzzy Decision Making Criterion
NASA Astrophysics Data System (ADS)
Rehman, Inayatur; Shah, Tariq; Hussain, Iqtadar
2014-06-01
In this manuscript, we put forward a standard based on fuzzy decision making criterion to examine the current substitution boxes and study their strengths and weaknesses in order to decide their appropriateness in image encryption applications. The proposed standard utilizes the results of correlation analysis, entropy analysis, contrast analysis, homogeneity analysis, energy analysis, and mean of absolute deviation analysis. These analyses are applied to well-known substitution boxes. The outcome of these analyses are additional observed and a fuzzy soft set decision making criterion is used to decide the suitability of an S-box to image encryption applications.
NASA Astrophysics Data System (ADS)
Wang, Cong; Shang, De-Guang; Wang, Xiao-Wei
2015-02-01
An improved high-cycle multiaxial fatigue criterion based on the critical plane was proposed in this paper. The critical plane was defined as the plane of maximum shear stress (MSS) in the proposed multiaxial fatigue criterion, which is different from the traditional critical plane based on the MSS amplitude. The proposed criterion was extended as a fatigue life prediction model that can be applicable for ductile and brittle materials. The fatigue life prediction model based on the proposed high-cycle multiaxial fatigue criterion was validated with experimental results obtained from the test of 7075-T651 aluminum alloy and some references.
easyCBM® Reading Criterion Related Validity Evidence: Grades K-1. Technical Report #1309
ERIC Educational Resources Information Center
Lai, Cheng-Fei; Alonzo, Julie; Tindal, Gerald
2013-01-01
In this technical report, we present the results of a study to gather criterion-related evidence for Grade K-1 easyCBM® reading measures. We used correlations to examine the relation between the easyCBM® measures and other published measures with known reliability and validity evidence, including the Dynamic Indicators of Basic Early Literacy…
easyCBM® Reading Criterion Related Validity Evidence: Grades 2-5. Technical Report #1310
ERIC Educational Resources Information Center
Lai, Cheng-Fei; Alonzo, Julie; Tindal, Gerald
2013-01-01
In this technical report, we present the results of a study to gather criterion-related evidence for Grade 2-5 easyCBM® reading measures. We used correlations to examine the relation between the easyCBM® measures and other published measures with known reliability and validity evidence, including the Gates-MacGinitie Reading Tests and the Dynamic…
Criterion-Referenced Assessment for Language Organization: An Example of Evidence-Based Practice
ERIC Educational Resources Information Center
Klecan-Aker, Joan S.; Colson, Karen
2009-01-01
Reliable criterion-referenced assessments are critical as one of the first steps in evidence-based practice. These assessments must also be valid. One of the most important skills to measure in school-age children with language disabilities is the ability to organize language in the form of narratives. The purpose of this paper is to describe a…
Measures and Interpretations of Vigilance Performance: Evidence Against the Detection Criterion
NASA Technical Reports Server (NTRS)
Balakrishnan, J. D.
1998-01-01
Operators' performance in a vigilance task is often assumed to depend on their choice of a detection criterion. When the signal rate is low this criterion is set high, causing the hit and false alarm rates to be low. With increasing time on task the criterion presumably tends to increase even further, thereby further decreasing the hit and false alarm rates. Virtually all of the empirical evidence for this simple interpretation is based on estimates of the bias measure Beta from signal detection theory. In this article, I describe a new approach to studying decision making that does not require the technical assumptions of signal detection theory. The results of this new analysis suggest that the detection criterion is never biased toward either response, even when the signal rate is low and the time on task is long. Two modifications of the signal detection theory framework are considered to account for this seemingly paradoxical result. The first assumes that the signal rate affects the relative sizes of the variances of the information distributions; the second assumes that the signal rate affects the logic of the operator's stopping rule. Actual or potential applications of this research include the improved training and performance assessment of operators in areas such as product quality control, air traffic control, and medical and clinical diagnosis.
Towards the Characterization of Genre: Speech Act of Definition: A Criterion for Genre Identity.
ERIC Educational Resources Information Center
Ansary, Hasan; Babai, Esmat
2000-01-01
Presents results of a study on the speech act of definition in chemistry texts within two genres investigating whether or not it can serve as a criterion to differentiate the two genres. A random sample of 60 texts written by different writers served as the corpus of the study. Results suggest that definitions often cluster together in textbooks,…
ERIC Educational Resources Information Center
Muhich, Dolores
1976-01-01
Criterion Referenced Measurement (CRM) in the initial acquisition of the psychomotor skill of typewriting demonstrated speed gains from 8 hours of instruction distributed over a 6-week interval for 4 male adolescent underachievers of above- and below-average intelligence. (Author)
V-TECS Criterion-Referenced Test Item Bank for Radiologic Technology Occupations.
ERIC Educational Resources Information Center
Reneau, Fred; And Others
This Vocational-Technical Education Consortium of States (V-TECS) criterion-referenced test item bank provides 696 multiple-choice items and 33 matching items for radiologic technology occupations. These job titles are included: radiologic technologist, chief; radiologic technologist; nuclear medicine technologist; radiation therapy technologist;…
V-TECS Criterion-Referenced Test Item Bank for Ornamental Horticulture Production Occupations.
ERIC Educational Resources Information Center
Reneau, Fred; And Others
This Vocational-Technical Education Consortium of States (V-TECS) criterion-referenced test item bank provides 325 multiple-choice items and 18 matching items for ornamental horticulture production occupations. Job titles covered are specialty grower, plant propagator, and horticultural worker I and II. The following information is provided in…
ERIC Educational Resources Information Center
Lee, Kerry; Bussey, Kay
1999-01-01
Examined effects of misleading or inconsistent post-event information on 7-year olds' recollections. Misinformation was administered on one or three occasions two days after learning a target game. Found that three weeks later, even criterion-learned information could be affected detrimentally by misinformation exposure. Children given…
Evaluation of Self-Perceptions of Creativity: Is It a Useful Criterion?
ERIC Educational Resources Information Center
Reiter-Palmon, Roni; Robinson-Morral, Erika J.; Kaufman, James C.; Santo, Jonathan B.
2012-01-01
Self-evaluations or self-perceptions of creativity have been used in the past both as predictors of creative performance and as criteria. Four measures utilizing self-perceptions of creativity were assessed for their usefulness as criterion measures of creativity. Analyses provided evidence of domain specificity of self-perceptions. The scales…
Localized stability criterion for kink modes in systems with small shear
Hastie, R.J.; Johnson, J.L.
1986-02-01
A localized magnetohydrodynamic stability criterion for ideal kink instabilities is determined for systems where the safety factor has a local minimum on a rational surface with no pressure gradient. These modes are stable in the cylindrical limit, but toroidal effects can make them unstable. They could provide a partial explanation for the rapid current penetration observed in tokamaks. 7 refs.
Test-Retest Reliability and Criterion Validity of the Chinese Version of CBCL, TRF, and YSR
ERIC Educational Resources Information Center
Leung, Patrick W. L.; Kwong, S. L.; Tang, C. P.; Ho, T. P.; Hung, S. F.; Lee, C. C.; Hong, S. L.; Chiu, C. M.; Liu, W. S.
2006-01-01
Background: Psychometric properties of the Chinese version of CBCL, TRF, and YSR were understudied. This study aimed at examining their test-retest reliability and criterion validity. Methods: Three Chinese community and clinic samples were recruited in Hong Kong. The parents, teachers, and youths respectively completed the CBCL, TRF, and YSR.…
Criterion-Referenced Test (CRT) Items for Air Conditioning, Heating and Refrigeration.
ERIC Educational Resources Information Center
Davis, Diane, Ed.
These criterion-referenced test (CRT) items for air conditioning, heating, and refrigeration are keyed to the Missouri Air Conditioning, Heating, and Refrigeration Competency Profile. The items are designed to work with both the Vocational Instructional Management System and Vocational Administrative Management System. For word processing and…
ERIC Educational Resources Information Center
Harris, Larry P.; Wolf, Steven R.
1979-01-01
The article focuses on the controversy over norm-referenced v criterion-referenced measures (CRM) in assessment of learning disorders. The authors contend that while the reliability of CRMs is generally indisputable, the validity of measures designed from local curricula is still dependent on the intuitive judgments of teachers. (Author/SBH)
ERIC Educational Resources Information Center
Meredith, Keith E.; Sabers, Darrell L.
Data required for evaluating a Criterion Referenced Measurement (CRM) is described with a matrix. The information within the matrix consists of the "pass-fail" decisions of two CRMs. By differentially defining these two CRMs, different concepts of reliability and validity can be examined. Indices suggested for analyzing the matrix are listed with…
A measurable Lawson criterion and hydro-equivalent curves for inertial confinement fusion
Zhou, C. D.; Betti, R.
2008-01-01
This article demonstrates how the ignition condition (Lawson criterion) for inertial confinement fusion (ICF) can be cast in a form depending on the only two parameters of the compressed fuel assembly that can be measured with methods already in existence: the hot spot ion temperature and the total areal density.
ERIC Educational Resources Information Center
Kelly, William E.; Lutz, Daniel
2014-01-01
The concurrent criterion validity of the Ausburg Multidimensional Personality Instrument (AMPI) clinical scales was examined. The AMPI and several scales purportedly measuring the same or similar constructs as those of the AMPI clinical scales were administered to two samples of college students (N = 134 and N = 118). The correlations between the…
ERIC Educational Resources Information Center
Fidler, James R.
1993-01-01
Criterion-related validities of 2 laboratory practitioner certification examinations for medical technologists (MTs) and medical laboratory technicians (MLTs) were assessed for 81 MT and 70 MLT examinees. Validity coefficients are presented for both measures. Overall, summative ratings yielded stronger validity coefficients than ratings based on…
Vorticity Curvature Criterion for the Identification of Two-Dimensional Vortex Structures
NASA Astrophysics Data System (ADS)
Elsas, José Hugo; Moriconi, Luca
2015-11-01
Systematic procedures for the identification of vortices/coherent structures have been proposed as a way to address their kinematical and dynamical roles in structural formulations of turbulence. As a general rule, all of the known vortex detection algorithms are plagued with shortcomings. In this work, we focus on one of the most popular methods - the swirling strength criterion - and investigate how it performs in controled Monte-Carlo tests. We, then, emphasize its main problematic issues: (i) vortex deformation and suppression due to near presence of intense vortical structures; (ii) vortex merging; (iii) spuriuos vortices created in many-vortex configurations and (iv) in the presence of background shear. The inner layer of turbulent boundary layer flows is, in particular, the region where the swirling strength criterion looses accuracy in a dramatic way. We propose an alternative vortex detection criterion, based on the curvature properties of the vorticity profile, which clearly improves over the results obtained with the swirling strength criterion in a number of relevant two-dimensional case studies.
ERIC Educational Resources Information Center
Rolider, Ahmos; Van Houten, Ron
1986-01-01
Two components of a gradually faded awakening procedure for treating bedwetting were tested with six children aged 4-11. Thorough awakening was more effective than partial awakening. A second experiment on advancing awakening time produced similar results between a stringent 6 consecutive dry night criterion and a more lenient 6 dry night…
A More Practical Pedagogical Ideal: Searching for a Criterion of Deweyan Growth
ERIC Educational Resources Information Center
Ralston, Shane Jesse
2011-01-01
When Dewey scholars and educational theorists appeal to the value of educative growth, what exactly do they mean? Is an individual's growth contingent on receiving a formal education? Is growth too abstract a goal for educators to pursue? Richard Rorty contended that the request for a "criterion of growth" is a mistake made by John Dewey's…
ERIC Educational Resources Information Center
Duval County School Board, Jacksonville, FL.
Several intermediate performance objectives and corresponding criterion measures are presented for each of five terminal objectives for a 12- to 18-week course designed to provide students in grades eight or nine with opportunities for exploring a broad range of child care, guidance, and service occupations. Major concepts include characteristics…
Fundamentals of Child Care Occupations. 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 four terminal objectives for a fundamentals of child care occupations course. The materials were designed to prepare students for entry level employment in jobs involving the care and guidance of children. Major concepts include growth,…
ERIC Educational Resources Information Center
Dobbins, Ian G.; Kroll, Neal E. A.
2005-01-01
Superior detection and rejection of 1 versus another class of items during recognition is called the mirror effect. Some mirror effects may involve strategic criterion adjustments based on item distinctiveness and its relation to memorability. Three experiments demonstrated mirror effects for known versus unknown scenes and 1 suggested a similar…
Criterion-Referenced Tests for the SWRL Kindergarten Curriculum. TM-3-72-06.
ERIC Educational Resources Information Center
Niedermeyer, Fred; Giguere, Connie
Criterion-referenced tests developed for four programs in the Southwest Regional Laboratory (SWRL) Kindergarten Curriculum are presented. Tests were developed to meet the following criteria: (1) they must accurately and thoroughly reflect the objectives and learning activities of the program, (2) when appropriate, they must be designed to allow…
The Development of a Criterion-Referenced Functional Literacy Test for Miami-Dade Students.
ERIC Educational Resources Information Center
Skellings, Louise Noah
In recognition of the trend toward functional illiteracy, this study developed and evaluated a criterion-referenced functional literacy test for use in diagnosis and evaluation of Miami-Dade Community College English students. The instrument was pilot-tested on 135 composition students in the fall of 1976, then revised after item analysis and…
A Latent Trait Look at Pretest-Posttest Validation of Criterion-referenced Test Items.
ERIC Educational Resources Information Center
van der Linden, Wim J.
1981-01-01
Using criterion-referenced test item data collected in an empirical study, differences in item selection between Cox and Vargas' pretest-posttest validity index and a latent trait approach (evaluation of the item information function for the mastery score) are analyzed. (Author/GK)
ERIC Educational Resources Information Center
Simpson, Mary; Arnold, Brian
1983-01-01
Suggests that failure to learn is often the result of inappropriateness of level of instruction and deficiencies in instructional procedures and educational strategies, and differentiates between the functions of criterion referenced tests and diagnostic tests. Results are reported from two studies of the teaching of osmosis and photosynthesis.…
Jaman, Ajmery; Latif, Mahbub A H M; Bari, Wasimul; Wahed, Abdus S
2016-05-20
In generalized estimating equations (GEE), the correlation between the repeated observations on a subject is specified with a working correlation matrix. Correct specification of the working correlation structure ensures efficient estimators of the regression coefficients. Among the criteria used, in practice, for selecting working correlation structure, Rotnitzky-Jewell, Quasi Information Criterion (QIC) and Correlation Information Criterion (CIC) are based on the fact that if the assumed working correlation structure is correct then the model-based (naive) and the sandwich (robust) covariance estimators of the regression coefficient estimators should be close to each other. The sandwich covariance estimator, used in defining the Rotnitzky-Jewell, QIC and CIC criteria, is biased downward and has a larger variability than the corresponding model-based covariance estimator. Motivated by this fact, a new criterion is proposed in this paper based on the bias-corrected sandwich covariance estimator for selecting an appropriate working correlation structure in GEE. A comparison of the proposed and the competing criteria is shown using simulation studies with correlated binary responses. The results revealed that the proposed criterion generally performs better than the competing criteria. An example of selecting the appropriate working correlation structure has also been shown using the data from Madras Schizophrenia Study. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26626276
A universal approximate cross-validation criterion for regular risk functions.
Commenges, Daniel; Proust-Lima, Cécile; Samieri, Cécilia; Liquet, Benoit
2015-05-01
Selection of estimators is an essential task in modeling. A general framework is that the estimators of a distribution are obtained by minimizing a function (the estimating function) and assessed using another function (the assessment function). A classical case is that both functions estimate an information risk (specifically cross-entropy); this corresponds to using maximum likelihood estimators and assessing them by Akaike information criterion (AIC). In more general cases, the assessment risk can be estimated by leave-one-out cross-validation. Since leave-one-out cross-validation is computationally very demanding, we propose in this paper a universal approximate cross-validation criterion under regularity conditions (UACVR). This criterion can be adapted to different types of estimators, including penalized likelihood and maximum a posteriori estimators, and also to different assessment risk functions, including information risk functions and continuous rank probability score (CRPS). UACVR reduces to Takeuchi information criterion (TIC) when cross-entropy is the risk for both estimation and assessment. We provide the asymptotic distributions of UACVR and of a difference of UACVR values for two estimators. We validate UACVR using simulations and provide an illustration on real data both in the psychometric context where estimators of the distributions of ordered categorical data derived from threshold models and models based on continuous approximations are compared. PMID:25849800
Continuing My Journey on Designing and Refining Criterion-Referenced Assessment Rubrics
ERIC Educational Resources Information Center
Burton, Kelley
2015-01-01
The article "Designing criterion-referenced assessment" (Burton, 2006) appeared in the "Journal of Learning Design," Volume 1, Issue 2 in 2006. Nine years later, Associate Professor Burton reflects upon her original article. when the article was written, the author worked at the Queensland University of Technology (QUT). At…
Food and Nutrition (Intermediate). Performance Objectives and Criterion-Referenced Test Items.
ERIC Educational Resources Information Center
Missouri Univ., Columbia. Instructional Materials Lab.
This document contains competencies and criterion-referenced test items for the Intermediate Food and Nutrition semester course in Missouri that were derived from the duties and tasks of the Missouri homemaker and identified and validated by home economics teachers and subject matter specialists. The guide is designed to assist home economics…
46 CFR 175.200 - Gross tonnage as criterion for requirements.
Code of Federal Regulations, 2010 CFR
2010-10-01
..., equipment, intended service, and operating area. The criterion for application of this subchapter is the... formulation, will circumvent or be incompatible with the application of specific regulations for a vessel of... Section 175.200 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER...
46 CFR 70.05-20 - Gross tonnage as a criterion for requirements.
Code of Federal Regulations, 2010 CFR
2010-10-01
... Section 70.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS GENERAL PROVISIONS Application § 70.05-20 Gross tonnage as a criterion for requirements. (a) The... devices in the basic gross tonnage formulation, will circumvent or be incompatible with the application...
DXA: Can it be used as a criterion reference for body fat measurements in children?
Technology Transfer Automated Retrieval System (TEKTRAN)
Dual-energy X-ray absorptiometry (DXA) is often cited as a criterion method for body composition measurements. We have previously shown that a new DXA software version (Hologic Discovery V12.1) will affect whole-body bone mineral results for subjects weighing less than 40 kg. We wished to re-analy...
ERIC Educational Resources Information Center
Levy, Deborah L.; Bowman, Elizabeth A.; Abel, Larry; Krastoshevsky, Olga; Krause, Verena; Mendell, Nancy R.
2008-01-01
The "co-familiality" criterion for an endophenotype has two requirements: (1) clinically unaffected relatives as a group should show both a shift in mean performance and an increase in variance compared with controls; (2) performance scores should be heritable. Performance on the antisaccade task is one of several candidate endophenotypes for…
A nonlinear flow-transition criterion for the onset of slugging in horizontal channels and pipes
NASA Astrophysics Data System (ADS)
Campbell, Bryce K.; Liu, Yuming
2016-08-01
In this work, the interfacial instability and transition of a two-fluid flow from a stratified state to large amplitude waves or slugs is considered. By combining an asymptotic approximation of the linear Orr-Sommerfeld analysis with nonlinear resonant wave interaction theory, a novel nonlinear slug-transition criterion is derived. This criterion corresponds to a bounding condition on the upper fluid's velocity in order to limit the amount of energy (provided by the linear instability) which is transferred to long waves through resonant wave interactions. It is proposed that such a condition can predict the formation of large-amplitude long waves and/or slugs. Quantitative comparisons of the onset of slugging are made between the prediction by the nonlinear transition criterion and the experimental measurements carried out in a horizontal square channel. Good agreement is observed. An additional heuristic model is developed which generalizes the transition criterion to flow through horizontal pipes. Comparisons are made for flows through different pipe diameters and over a wide range of fluid properties. Good agreement between the present theoretical predictions and the experimental measurements is also observed.
Criterion Validation of a Written Multiple-Choice Test of Spanish/English Bilingual Skills.
ERIC Educational Resources Information Center
Doyle, Teresa F.; Lin, Thung-Rung
Supervisory performance appraisals may be of limited utility in the validation of bilingual tests because incumbents are often hired to be the only employee in a unit who possesses the skills necessary to do the job. In an effort to provide criterion-related validity for four equivalent forms of a Spanish/English bilingual test for school district…
ERIC Educational Resources Information Center
Salloum, Alison; Scheeringa, Michael S.; Cohen, Judith A.; Storch, Eric A.
2015-01-01
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/non-response to the…
16 CFR 1631.34 - Small carpets and rugs not meeting acceptance criterion.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Small carpets and rugs not meeting acceptance criterion. 1631.34 Section 1631.34 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE SURFACE FLAMMABILITY OF SMALL CARPETS AND RUGS (FF...
ERIC Educational Resources Information Center
Lee, HyeSun; Geisinger, Kurt F.
2016-01-01
The current study investigated the impact of matching criterion purification on the accuracy of differential item functioning (DIF) detection in large-scale assessments. The three matching approaches for DIF analyses (block-level matching, pooled booklet matching, and equated pooled booklet matching) were employed with the Mantel-Haenszel…
Consumer Education--Home Economics. 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 six terminal objectives for an 18-week consumer education-home economics course for 10th, 11th, and 12th grade students. Purposes listed for the course are to develop an understanding of the American market system, and how the individual affects…
The cut-off criterion for a positive hydrogen breath test in children: a reappraisal.
Solomons, N W; Barillas, C
1986-01-01
Seventy-three preschool children with adequate nutritional status underwent interval-sampling, 3-hour breath-hydrogen carbohydrate absorption tests after consuming either 240 ml of intact milk (containing 12 g of lactose) or the same volume of milk with 90-95% of its lactose prehydrolyzed in vitro (containing less than 1 g lactose, with the remaining sugar as glucose and galactose). Results were examined in a reappraisal of the cut-off criterion for the rise of breath H2 concentration signifying biologically incomplete absorption. If the greater than or equal to 10-ppm criterion advocated by some investigators is used, 83% of our subjects would have been classified as incomplete lactose digesters and 30% would have their tests with the monosaccharide-rich milk classified as positive. With the greater than or equal to 20 ppm criterion used in our laboratory and others, the prevalence of lactose maldigestion in the sample becomes 60% and only 4% of subjects have apparent monosaccharide absorption, 96% having a rise below the cut-off level with prehydrolyzed milk. At least in Guatemalan preschoolers, the 20-ppm criterion for a positive breath H2 test provides a superior specificity-sensitivity balance and more reasonable diagnostic conclusions. PMID:3794911
ERIC Educational Resources Information Center
Duval County School Board, Jacksonville, FL.
Several intermediate performance objectives and corresponding criterion measures are listed for each of seven terminal objectives for a 6- to 9-week orientation to home economics occupations course for seventh grade students. The titles of the seven terminal objectives are Overview, Human Care Cluster, Food and Nutrition, Home Service Cluster,…
Reviewing Employee Turnover: Focusing on Proximal Withdrawal States and an Expanded Criterion
ERIC Educational Resources Information Center
Hom, Peter W.; Mitchell, Terence R.; Lee, Thomas W.; Griffeth, Rodger W.
2012-01-01
We reconceptualize employee turnover to promote researchers' understanding and prediction of why employees quit or stay in employing institutions. A literature review identifies shortcomings with prevailing turnover dimensions. In response, we expand the conceptual domain of the turnover criterion to include multiple types of turnover (notably,…
46 CFR 167.01-8 - Inspection of school ships using gross tonnage criterion.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 7 2014-10-01 2014-10-01 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...
ERIC Educational Resources Information Center
Murray, Gregory V.; Moyer-Packenham, Patricia S.
2014-01-01
One option for length of individual mathematics class periods is the schedule type selected for Algebra I classes. This study examined the relationship between student achievement, as indicated by Algebra I Criterion-Referenced Test scores, and the schedule type for Algebra I classes. Data obtained from the Utah State Office of Education included…
Using the brain criterion in organ donation after the circulatory determination of death.
Dalle Ave, Anne L; Bernat, James L
2016-06-01
The UK, France, and Switzerland determine death using the brain criterion even in organ donation after the circulatory determination of death (DCDD), in which the United States and Canada use the circulatory-respiratory criterion. In our analysis of the scientific validity of the brain criterion in DCDD, we concluded that although it may be attractive in theory because it conceptualizes death as a unitary phenomenon, its use in practice is invalid. The preconditions (ie, the absence of reversible causes, such as toxic or metabolic disorders) for determining brain death cannot be met in DCDD. Thus, although brain death tests prove the cessation of tested brain functions, they do not prove that their cessation is irreversible. A stand-off period of 5 to 10 minutes is insufficient to achieve the irreversibility requirement of brain death. Because circulatory cessation inevitably leads to cessation of brain functions, first permanently and then irreversibly, the use of brain criterion is unnecessary to determine death in DCDD. Expanding brain death to permit it to be satisfied by permanent cessation of brain functions is controversial but has been considered as a possible means to declare death in uncontrolled DCDD. PMID:26857329
Time-Score Analysis in Criterion-Referenced Tests. Final Report.
ERIC Educational Resources Information Center
Tatsuoka, Kikumi K.; Tatsuoka, Maurice M.
The family of Weibull distributions was investigated as a model for the distributions of response times for items in computer-based criterion-referenced tests. The fit of these distributions were, with a few exceptions, good to excellent according to the Kolmogorov-Smirnov test. For a few relatively simple items, the two-parameter gamma…
A Criterion-Referenced Assessment of Reading Literacy Using the Cloze Procedure.
ERIC Educational Resources Information Center
Hansen, Lee H.; Hesse, Karl D.
Students at four grade levels (4,7,10, and 12) were tested using a criterion-referenced measure of reading literacy based on the Bormuth literacy model. Cloze test passages were selected to represent a cross section of ten content domains of readers material (e.g., textbooks, consumer safety, occupational, etc.). A multimatrix sampling design was…
34 CFR 388.20 - What additional selection criterion is used under this program?
Code of Federal Regulations, 2013 CFR
2013-07-01
... criterion is used under this program? In addition to the selection criteria in 34 CFR 385.31(c), the.... (1) The Secretary reviews each application for information that shows that the need for the in-service training has been adequately justified. (2) The Secretary looks for information that shows—...
34 CFR 388.20 - What additional selection criterion is used under this program?
Code of Federal Regulations, 2014 CFR
2014-07-01
... criterion is used under this program? In addition to the selection criteria in 34 CFR 385.31(c), the.... (1) The Secretary reviews each application for information that shows that the need for the in-service training has been adequately justified. (2) The Secretary looks for information that shows—...
34 CFR 388.20 - 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 selection criteria in 34 CFR 385.31(c), the.... (1) The Secretary reviews each application for information that shows that the need for the in-service training has been adequately justified. (2) The Secretary looks for information that shows—...
34 CFR 388.20 - 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 selection criteria in 34 CFR 385.31(c), the.... (1) The Secretary reviews each application for information that shows that the need for the in-service training has been adequately justified. (2) The Secretary looks for information that shows—...
34 CFR 388.20 - What additional selection criterion is used under this program?
Code of Federal Regulations, 2012 CFR
2012-07-01
... criterion is used under this program? In addition to the selection criteria in 34 CFR 385.31(c), the.... (1) The Secretary reviews each application for information that shows that the need for the in-service training has been adequately justified. (2) The Secretary looks for information that shows—...
Evaluation of Revision Effect on Criterion Validity of Multiple-Component Measuring Instruments
ERIC Educational Resources Information Center
Raykov, Tenko
2007-01-01
A method for point and interval estimation of change in criterion validity of multiple-component measuring instruments as a result of revision is outlined. The procedure is developed within the framework of covariance structure modeling, which complements earlier methods for testing change in composite reliability due to addition or deletion of…
ERIC Educational Resources Information Center
Hymel, Glenn M.
This paper advances the argument favoring criterion-referenced/modular-based instruction (CRMBI) as applied to training and educational efforts in business, industrial, and military settings. CRMBI is defined as an instructional delivery system (along with the concomitant curriculum design and instructional materials development implications) that…
A Case for Transforming the Criterion of a Predictive Validity Study
ERIC Educational Resources Information Center
Patterson, Brian F.; Kobrin, Jennifer L.
2011-01-01
This study presents a case for applying a transformation (Box and Cox, 1964) of the criterion used in predictive validity studies. The goals of the transformation were to better meet the assumptions of the linear regression model and to reduce the residual variance of fitted (i.e., predicted) values. Using data for the 2008 cohort of first-time,…
Statistical Techniques for Criterion-Referenced Tests. Final Report. October, 1976-October, 1977.
ERIC Educational Resources Information Center
Wilcox, Rand R.
Three statistical problems related to criterion-referenced testing are investigated: estimation of the likelihood of a false-positive or false-negative decision with a mastery test, estimation of true scores in the Compound Binomial Error Model, and comparison of the examinees to a control. Two methods for estimating the likelihood of…
The Applicability of Criterion-Referenced Measurement by Content Area and Level.
ERIC Educational Resources Information Center
Garvin, Alfred D.
In choosing between criterion-referenced and norm-referenced measurement strategy we should consider the nature of the decisions to be based on the resulting scores. If the decision involves selecting some fixed quota from the high (or low) end of an available competence continuum, then norm-referenced measurement is indicated. If, however, the…
ERIC Educational Resources Information Center
Kim, Seonghoon; Kolen, Michael J.
2007-01-01
Under item response theory, the characteristic curve methods (Haebara and Stocking-Lord methods) are used to link two ability scales from separate calibrations. The linking methods use their respective criterion functions that can be defined differently according to the symmetry- and distribution-related schemes. The symmetry-related scheme…
ERIC Educational Resources Information Center
Steinheiser, Frederick H., Jr.; And Others
Alternative mathematical models for scoring and decision making with criterion referenced tests are described, especially as they concern appropriate test length and methods of establishing statistically valid cutting scores. Several of these approaches are reviewed and compared on formal-analytic and empirical grounds: (1) Block's approach to…
Family and Individual Health. Performance Objectives and Criterion-Referenced Test Items.
ERIC Educational Resources Information Center
Missouri Univ., Columbia. Instructional Materials Lab.
This document contains competencies and criterion-referenced test items for the Family/Individual Health semester course in Missouri that were derived from the duties and tasks of the Missouri homemaker and identified and validated by home economics teachers and subject-matter specialists. The guide is designed to assist home economics teachers in…
NASA Astrophysics Data System (ADS)
Severn, Greg; Green, Jonathan; Winters, Victoria; Yip, Chi-Shung; Hershkowitz, Noah; Schmitz, Oliver
2015-09-01
It is taken for granted that the usual Bohm criterion must be satisfied for weakly collisional, magnetized plasmas at the plasma-wall boundary for the case in which the magnetic field is normally incident on the boundary, but there is a paucity of experimental works that confirm it. Beyond this, theorists view the Bohm criterion as approximately true, holding only for collisionless plasmas. The question is whether Bohm's criterion really is satisfied in weakly collisional magnetized plasmas in the simplest case (n ∧ ∥ B /B, where n ∧ is the boundary surface normal vector) and how that criterion (the ions reaching a sonic point at the end of the presheath) is modified as collisionality rises. Experiments are conducted in a linear magnetized helicon plasma source at the University of Wisconsin, Madison, an upgraded version of MARIA (MARIA-Magnetized Anisot Ropic Ion-distribution Apparatus), in order to address these questions. Experimental results are discussed in light of relevant theoretical works. Work supported by NSF Grant Nos. PHY-1206421, CBET-0903783, and CBET-0903832, and MSN178461, and DOE Grant Nos. DE-FG02-97ER54437, DE FG02-03ER54728, and MSN170010.
The Criterion-Related Validity of a Computer-Based Approach for Scoring Concept Maps
ERIC Educational Resources Information Center
Clariana, Roy B.; Koul, Ravinder; Salehi, Roya
2006-01-01
This investigation seeks to confirm a computer-based approach that can be used to score concept maps (Poindexter & Clariana, 2004) and then describes the concurrent criterion-related validity of these scores. Participants enrolled in two graduate courses (n=24) were asked to read about and research online the structure and function of the heart…
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. We discuss theoretical statistical results in regression and illustrate more important issues with novel simulations involving latent variable models including factor analysis, latent profile analysis, and factor mixture models. Asymptotically, the BIC is consistent, in that it will select the true model if, among other assumptions, the true model is among the candidate models considered. The AIC is not consistent under these circumstances. When the true model is not in the candidate model set the AIC is effcient, in that it will asymptotically choose whichever model minimizes the mean squared error of prediction/estimation. The BIC is not effcient under these circumstances. Unlike the BIC, the AIC also has a minimax property, in that it can minimize the maximum possible risk in finite sample sizes. In sum, the AIC and BIC have quite different properties that require different assumptions, and applied researchers and methodologists alike will benefit from improved understanding of the asymptotic and finite-sample behavior of these criteria. The ultimate decision to use AIC or BIC depends on many factors, including: the loss function employed, the study's methodological design, the substantive research question, and the notion of a true model and its applicability to the study at hand. PMID:22309957
ERIC Educational Resources Information Center
Notar, Charles E.; Herring, Donna F.; Restauri, Sherri L.
2008-01-01
Instructional tool in the form of a user-friendly, web-based navigational chart for pre-service as well as in-service teachers to teach norm referenced and criterion referenced testing. This chart was designed based on a major facet of testing: comparing and contrasting norm referenced and criterion referenced testing models (Kubiszyn & Borich,…
ERIC Educational Resources Information Center
Passos, Valeria Lima; Berger, Martijn P. F.; Tan, Frans E. S.
2008-01-01
During the early stage of computerized adaptive testing (CAT), item selection criteria based on Fisher"s information often produce less stable latent trait estimates than the Kullback-Leibler global information criterion. Robustness against early stage instability has been reported for the D-optimality criterion in a polytomous CAT with the…
ERIC Educational Resources Information Center
Mullins, Cecil J., Ed.; Winn, William R., Ed.
These conference proceedings contain statements from those concerned with various aspects of research on job performance measures. Following introductory remarks, the formal presentations of work and ideas include "Air Training Command Interest in the Criterion Problem," by Donald E. Meyer, "The Criterion Problem: A Personnel Management…
ERIC Educational Resources Information Center
Huynh, Huynh
2006-01-01
By analyzing the Fisher information allotted to the correct response of a Rasch binary item, Huynh (1994) established the response probability criterion 0.67 (RP67) for standard settings based on bookmarks and item mapping. The purpose of this note is to help clarify the conceptual and psychometric framework of the RP criterion.
Criterion distances and environmental correlates of active commuting to school in children
2011-01-01
Background Active commuting to school can contribute to daily physical activity levels in children. Insight into the determinants of active commuting is needed, to promote such behavior in children living within a feasible commuting distance from school. This study determined feasible distances for walking and cycling to school (criterion distances) in 11- to 12-year-old Belgian children. For children living within these criterion distances from school, the correlation between parental perceptions of the environment, the number of motorized vehicles per family and the commuting mode (active/passive) to school was investigated. Methods Parents (n = 696) were contacted through 44 randomly selected classes of the final year (sixth grade) in elementary schools in East- and West-Flanders. Parental environmental perceptions were obtained using the parent version of Neighborhood Environment Walkability Scale for Youth (NEWS-Y). Information about active commuting to school was obtained using a self-reported questionnaire for parents. Distances from the children's home to school were objectively measured with Routenet online route planner. Criterion distances were set at the distance in which at least 85% of the active commuters lived. After the determination of these criterion distances, multilevel analyses were conducted to determine correlates of active commuting to school within these distances. Results Almost sixty percent (59.3%) of the total sample commuted actively to school. Criterion distances were set at 1.5 kilometers for walking and 3.0 kilometers for cycling. In the range of 2.01 - 2.50 kilometers household distance from school, the number of passive commuters exceeded the number of active commuters. For children who were living less than 3.0 kilometers away from school, only perceived accessibility by the parents was positively associated with active commuting to school. Within the group of active commuters, a longer distance to school was associated with
Generalized melting criterion for amorphization. [NiZr, NiZr[sub 2], NiTi, FeTi
Devanathan, R. Northwestern Univ., Evanston, IL . Dept. of Materials Science and Engineering); Lam, N.Q.; Okamoto, P.R. ); Meshii, M. . Dept. of Materials Science and Engineering)
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.
A multiloop generalization of the circle criterion for stability margin analysis
NASA Technical Reports Server (NTRS)
Safonov, M. G.; Athans, M.
1979-01-01
In order to provide a theoretical tool suited for characterizing the stability margins of multiloop feedback systems, multiloop input-output stability results generalizing the circle stability criterion are considered. Generalized conic sectors with 'centers' and 'radii' determined by linear dynamical operators are employed to specify the stability margins as a frequency dependent convex set of modeling errors (including nonlinearities, gain variations and phase variations) which the system must be able to tolerate in each feedback loop without instability. The resulting stability criterion gives sufficient conditions for closed loop stability in the presence of frequency dependent modeling errors, even when the modeling errors occur simultaneously in all loops. The stability conditions yield an easily interpreted scalar measure of the amount by which a multiloop system exceeds, or falls short of, its stability margin specifications.
Variable selection for logistic regression using a prediction-focused information criterion.
Claeskens, Gerda; Croux, Christophe; Van Kerckhoven, Johan
2006-12-01
In biostatistical practice, it is common to use information criteria as a guide for model selection. We propose new versions of the focused information criterion (FIC) for variable selection in logistic regression. The FIC gives, depending on the quantity to be estimated, possibly different sets of selected variables. The standard version of the FIC measures the mean squared error of the estimator of the quantity of interest in the selected model. In this article, we propose more general versions of the FIC, allowing other risk measures such as the one based on L(p) error. When prediction of an event is important, as is often the case in medical applications, we construct an FIC using the error rate as a natural risk measure. The advantages of using an information criterion which depends on both the quantity of interest and the selected risk measure are illustrated by means of a simulation study and application to a study on diabetic retinopathy. PMID:17156270
Learning image based surrogate relevance criterion for atlas selection in segmentation
NASA Astrophysics Data System (ADS)
Zhao, Tingting; Ruan, Dan
2016-06-01
Picking geometrically relevant atlases from the whole training set is crucial to multi-atlas based image segmentation, especially with extensive data of heterogeneous quality in the Big Data era. Unfortunately, there is very limited understanding of how currently used image similarity criteria reveal geometric relevance, let alone the optimization of them. This paper aims to develop a good image based surrogate relevance criterion to best reflect the underlying inaccessible geometric relevance in a learning context. We cast this surrogate learning problem into an optimization framework, by encouraging the image based surrogate to behave consistently with geometric relevance during training. In particular, we desire a criterion to be small for image pairs with similar geometry and large for those with significantly different segmentation geometry. Validation experiments on corpus callosum segmentation demonstrate the improved quality of the learned surrogate compared to benchmark surrogate candidates.
Crack nucleation criterion and its application to impact indentation in glasses.
Luo, Jian; Vargheese, K Deenamma; Tandia, Adama; Hu, Guangli; Mauro, John C
2016-01-01
Molecular dynamics (MD) simulations are used to directly observe nucleation of median cracks in oxide glasses under indentation. Indenters with sharp angles can nucleate median cracks in samples with no pre-existing flaws, while indenters with larger indenter angles cannot. Increasing the tip radius increases the critical load for nucleation of the median crack. Based upon an independent set of simulations under homogeneous loading, the fracture criterion in the domain of the principal stresses is constructed. The fracture criterion, or "fracture locus", can quantitatively explain the observed effects of indenter angle and indenter tip radius on median crack nucleation. Our simulations suggest that beyond the maximum principal stress, plasticity and multi-axial stresses should also be considered for crack nucleation under indentation, even for brittle glassy systems. PMID:27079431
Aggressive Attitudes in Middle Schools: A Factor Structure and Criterion-Related Validity Study.
Huang, Francis L; Cornell, Dewey G; Konold, Timothy R
2015-08-01
Student attitudes toward aggression have been linked to individual aggressive behavior, but the relationship between school-wide normative beliefs about aggression and aggressive behavior poses some important measurement challenges that have not been adequately examined. The current study investigated the factor structure, measurement invariance, and criterion-related validity of a six-item Aggressive Attitudes scale using a large sample of seventh- and eighth-grade students (n = 39,364) from 423 schools. Analytic procedures accounted for the frequently ignored modeling problems of clustered and ordinal data to provide more reliable and accurate model estimates and standard errors. The resulting second-order factor structure of the Aggressive Attitudes scale demonstrated measurement invariance across gender, grade, and race/ethnicity groups. Criterion-related validity was supported with eight student- and school-level indices of aggressive behavior. PMID:25225231
Unified criterion for security of secret sharing in terms of violation of Bell inequalities
Sen, Aditi; Sen, Ujjwal; Zukowski, Marek
2003-09-01
In secret sharing protocols, a secret is to be distributed among several partners such that leaving out any number of them, the rest do not have the complete information. Strong multiqubit correlations in the state by which secret sharing is carried out had been proposed as a criterion for security of such protocols against individual attacks by an eavesdropper. However we show that states with weak multiqubit correlations can also be used for secure secret sharing. That our state has weak multiqubit correlations is shown from the perspective of violation of local realism, and also by showing that its higher-order correlations are described by lower ones. We then present a unified criterion for security of secret sharing in terms of violation of local realism, which works when the secret sharing state is the Greenberger-Horne-Zeilinger state (with strong multiqubit correlations), as well as states of a different class (with weak multiqubit correlations)
Experimental evaluation of the tensor polynomial criterion for designing composite structures
NASA Technical Reports Server (NTRS)
Tennyson, R. C.
1977-01-01
A comprehensive experimental and analytical evaluation of the tensor polynomial failure criterion was undertaken to determine its capability for predicting the ultimate strength of a composite limina subject to a plane stress state. Results are presented demonstrating that a quadratic formulation is too conservative and a cubic representation is required. Strength comparisons with test data derived from glass/epoxy and graphite/epoxy tubular specimens are also provided to validate the cubic strength criterion. Environmental effects including ambient temperature, exposure to vacuum, length of post-cure time, and rate of cool down were also investigated. Behavior changes associated with polymer (epoxy) matrix composites were determined in terms of variations in stiffness and tensile strength.
A multiloop generalization of the circle criterion for stability margin analysis
NASA Technical Reports Server (NTRS)
Safonov, M. G.; Athans, M.
1981-01-01
In order to provide a theoretical tool well suited for use in characterizing the stability margins (e.g., gain and phase margins) of multiloop feedback systems, multiloop input-output stability results generalizing the circle stability criterion are considered. Generalized conic sectors with 'centers' and 'radii' determined by linear dynamical operators are employed to enable an engineer to specify the stability margins which he desires as a frequency-dependent convex set of modeling errors (including nonlinearities, gain variations, and phase variations) which the system must be able to tolerate in each feedback loop without instability. The resulting stability criterion gives sufficient conditions for closed-loop stability in the presence of such frequency-dependent modeling errors, even when the modeling errors occur simultaneously in all loops.
Learning image based surrogate relevance criterion for atlas selection in segmentation.
Zhao, Tingting; Ruan, Dan
2016-06-01
Picking geometrically relevant atlases from the whole training set is crucial to multi-atlas based image segmentation, especially with extensive data of heterogeneous quality in the Big Data era. Unfortunately, there is very limited understanding of how currently used image similarity criteria reveal geometric relevance, let alone the optimization of them. This paper aims to develop a good image based surrogate relevance criterion to best reflect the underlying inaccessible geometric relevance in a learning context. We cast this surrogate learning problem into an optimization framework, by encouraging the image based surrogate to behave consistently with geometric relevance during training. In particular, we desire a criterion to be small for image pairs with similar geometry and large for those with significantly different segmentation geometry. Validation experiments on corpus callosum segmentation demonstrate the improved quality of the learned surrogate compared to benchmark surrogate candidates. PMID:27192550
Crack nucleation criterion and its application to impact indentation in glasses
Luo, Jian; Vargheese, K. Deenamma; Tandia, Adama; Hu, Guangli; Mauro, John C
2016-01-01
Molecular dynamics (MD) simulations are used to directly observe nucleation of median cracks in oxide glasses under indentation. Indenters with sharp angles can nucleate median cracks in samples with no pre-existing flaws, while indenters with larger indenter angles cannot. Increasing the tip radius increases the critical load for nucleation of the median crack. Based upon an independent set of simulations under homogeneous loading, the fracture criterion in the domain of the principal stresses is constructed. The fracture criterion, or “fracture locus”, can quantitatively explain the observed effects of indenter angle and indenter tip radius on median crack nucleation. Our simulations suggest that beyond the maximum principal stress, plasticity and multi-axial stresses should also be considered for crack nucleation under indentation, even for brittle glassy systems. PMID:27079431
Wavelength selection in injection-driven Hele-Shaw flows: A maximum amplitude criterion
NASA Astrophysics Data System (ADS)
Dias, Eduardo; Miranda, Jose
2013-11-01
As in most interfacial flow problems, the standard theoretical procedure to establish wavelength selection in the viscous fingering instability is to maximize the linear growth rate. However, there are important discrepancies between previous theoretical predictions and existing experimental data. In this work we perform a linear stability analysis of the radial Hele-Shaw flow system that takes into account the combined action of viscous normal stresses and wetting effects. Most importantly, we introduce an alternative selection criterion for which the selected wavelength is determined by the maximum of the interfacial perturbation amplitude. The effectiveness of such a criterion is substantiated by the significantly improved agreement between theory and experiments. We thank CNPq (Brazilian Sponsor) for financial support.
Ethical leadership: meta-analytic evidence of criterion-related and incremental validity.
Ng, Thomas W H; Feldman, Daniel C
2015-05-01
This study examines the criterion-related and incremental validity of ethical leadership (EL) with meta-analytic data. Across 101 samples published over the last 15 years (N = 29,620), we observed that EL demonstrated acceptable criterion-related validity with variables that tap followers' job attitudes, job performance, and evaluations of their leaders. Further, followers' trust in the leader mediated the relationships of EL with job attitudes and performance. In terms of incremental validity, we found that EL significantly, albeit weakly in some cases, predicted task performance, citizenship behavior, and counterproductive work behavior-even after controlling for the effects of such variables as transformational leadership, use of contingent rewards, management by exception, interactional fairness, and destructive leadership. The article concludes with a discussion of ways to strengthen the incremental validity of EL. (PsycINFO Database Record PMID:25420055
Applicability problem of Jeans criterion to a stationary self-gravitating cloud
NASA Astrophysics Data System (ADS)
Cadez, V. M.
1990-08-01
The applicability of standard normal mode analysis with the resulting gravitational instability criterion is discussed for some typical configurations. It is shown that the small-perturbation method, generally used in the literature, has to be applied locally only, the reason being that the medium of a self-gravitating cloud cannot be considered 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 the Jeans criterion, the gravitational instability sets in for perturbations having their linear dimensions larger than some critical length, L(J), the Jeans length. It is therefore of some importance to estimate the value of the ratio L/L(J) in order to be sure that the local-analysis conclusions are meaningful.
Lee, K; Bussey, K
1999-07-01
Similar experimental procedures are used in misinformation studies and in retroactive inhibition studies. Despite these similarities, the findings of these studies have suggested that misleading postevent information and inconsistent postevent information would have different effects on children's recollections. To examine this hypothesis, 28 seven-year-olds learned a target game to criterion. Two days later, they were administered either type of postevent information on either one or three occasions. When the children were tested 3 weeks later, the results showed that even criterion-learned information could be affected detrimentally by exposure to misleading or inconsistent postevent information. Notably, children who were administered misinformation on one occasion reported more target information than children in all other groups. It is suggested that exposure to misinformation had a facilitative effect on these children's recollections. PMID:10357871
A2 diagnostic criterion for combat-related posttraumatic stress disorder.
Adler, Amy B; Wright, Kathleen M; Bliese, Paul D; Eckford, Rachel; Hoge, Charles W
2008-06-01
Individuals trained to respond to a potentially traumatic event may not experience the posttraumatic stress disorder (PTSD) A2 diagnostic criterion of fear, helplessness, or horror and yet may still report significant PTSD symptoms. The present study included interviews with 202 soldiers returning from a year in Iraq. Although reporting an A2 response was associated with higher PTSD Checklist scores, there were no significant differences in the percentage of subjects who met cutoff criteria for PTSD. The most common alternative A2 responses were related to military training and anger. The A2 criterion for PTSD should be expanded so as not to underestimate the number of individuals trained for high-risk occupations who might benefit from treatment. PMID:18553417
Application of the Electrical Network Frequency (ENF) Criterion. A case of a digital recording.
Kajstura, Mateusz; Trawinska, Agata; Hebenstreit, Jacek
2005-12-20
One of the new methods of investigating the authenticity of evidential digital audio recordings uses the Electrical Network Frequency (ENF) Criterion. It is based on analysing the signal corresponding to the fundamental frequency of the current in the electrical network, which is present in a recording and comparing it with appropriate, reliable reference. Studies carried out at the Institute of Forensic Research in Cracow were aimed at validating this method, that is, assessing its usefulness in forensic examinations of evidential digital recordings in Poland. These studies enabled us to develop and implement a procedure for using the ENF Criterion method to assess the integrity of digital recordings and to establish when these recordings were made. PMID:16226153
Chekour, S.; Tahraoui, A.; Zaham, B.
2012-05-15
In this work, we have generalized the computation of Bohm criterion for electronegative complex plasma in the presence of fast monoenergetic electrons coming from a plane electrode. For this, we have established a 1D, collisionless, stationary, and unmagnetized electronegative plasma sheath model. The electrons and negative ions are considered in thermodynamic equilibrium; however, the positive ions, the dust grains, and the fast monoenergetic electrons are described by cold fluid equations. The generalized Bohm criterion has been calculated by using Sagdeev's pseudo potential method and the dust grain charge equation. The self-consistent relation between the dust grain surface potential at the edge and dust grains density is also derived. The numerical results reveal that the presence of the fast monoenergetic electrons increases the positive ion Mach number. On the other hand, the raise of electronegativity decreases this positive Mach number. The evolution of dust grain surface potential at the sheath edge is also illustrated and discussed.
NASA Technical Reports Server (NTRS)
Wang, Bo Ping; Chu, F. H.
1989-01-01
In the design of spacecraft structures, fine tuning the structure to achieve minimum weight with natural frequency constraints is a time consuming process. Here, a novel implementation of the method of optimality criterion (OC) is developed. In this new implementation of OC, the free vibration analysis results are used to compute the eigenvalue sensitivity data required for the formulation. Specifically, the modal elemental strain and kinetic energies are used. Additionally, normalized design parameters are introduced as a second level linking that allows design variables of different values to be linked together. With the use of this novel formulation, synthesis of structures with natural frequency constraint can be carried out manually using modal analysis results. Design examples are presented to illustrate this novel implementation of the optimality criterion method.
A Breakdown Criterion of Free Molecular Flows and an Optimum Analysis of EBPVD
Li Shuaihui; Fan Jing; Shu Yonghua
2008-12-31
Two important issues in electron beam physical vapor deposition (EBPVD) are addressed. The first issue is a validity condition of the classical cosine law widely used in the engineering context. This requires a breakdown criterion of the free molecular assumption on which the cosine law is established. Using the analytical solution of free molecular effusion flow, the number of collisions (N{sub c}) for a particle moving from an evaporative source to a substrate is estimated that is proven inversely proportional to the local Knudsen number at the evaporation surface. N{sub c} = 1 is adopted as a breakdown criterion of the free molecular assumption, and it is verified by experimental data and DSMC results. The second issue is how to realize the uniform distributions of thickness and component over a large-area thin film. Our analysis shows that at relatively low evaporation rates the goal is easy achieved through arranging the evaporative source positions properly and rotating the substrate.
Constraints of energy conditions and DK instability criterion on f(R, Lm) gravity models
NASA Astrophysics Data System (ADS)
Wu, Ya-Bo; Zhao, Yue-Yue; Jin, Yong-Yi; Lin, Liang-Liang; Lu, Jian-Bo; Zhang, Xue
2014-06-01
Some properties of f(R, Lm) gravity are studied in this paper. Concretely, the energy conditions and the Dolgov-Kawasaki (DK) instability criterion in f(R, Lm) gravity are obtained, which are quite general and can degenerate to the ones in General Relativity (GR) and pure f(R) gravity with non-coupling and non-minimal coupling as well as in [J. Wang and K. Liao, Class. Quantum Grav. 29, 215016 (2012)] as special cases. Furthermore, in order to get some insight on the meaning of the energy conditions and the DK instability criterion, we apply them to the concrete type of f(R, Lm) gravity models and the corresponding constraints on the models are given.
Crack nucleation criterion and its application to impact indentation in glasses
NASA Astrophysics Data System (ADS)
Luo, Jian; Vargheese, K. Deenamma; Tandia, Adama; Hu, Guangli; Mauro, John C.
2016-04-01
Molecular dynamics (MD) simulations are used to directly observe nucleation of median cracks in oxide glasses under indentation. Indenters with sharp angles can nucleate median cracks in samples with no pre-existing flaws, while indenters with larger indenter angles cannot. Increasing the tip radius increases the critical load for nucleation of the median crack. Based upon an independent set of simulations under homogeneous loading, the fracture criterion in the domain of the principal stresses is constructed. The fracture criterion, or “fracture locus”, can quantitatively explain the observed effects of indenter angle and indenter tip radius on median crack nucleation. Our simulations suggest that beyond the maximum principal stress, plasticity and multi-axial stresses should also be considered for crack nucleation under indentation, even for brittle glassy systems.
A criterion for the onset of slugging in horizontal stratified air-water countercurrent flow
Chun, Moon-Hyun; Lee, Byung-Ryung; Kim, Yang-Seok
1995-09-01
This paper presents an experimental and theoretical investigation of wave height and transition criterion from wavy to slug flow in horizontal air-water countercurrent stratified flow conditions. A theoretical formula for the wave height in a stratified wavy flow regime has been developed using the concept of total energy balance over a wave crest to consider the shear stress acting on the interface of two fluids. From the limiting condition of the formula for the wave height, a necessary criterion for transition from a stratified wavy flow to a slug flow has been derived. A series of experiments have been conducted changing the non-dimensional water depth and the flow rates of air in a horizontal pipe and a duct. Comparisons between the measured data and the predictions of the present theory show that the agreement is within {plus_minus}8%.
Accuracy of visual estimates of joint angle and angular velocity using criterion movements.
Morrison, Craig S; Knudson, Duane; Clayburn, Colby; Haywood, Philip
2005-06-01
A descriptive study to document undergraduate physical education majors' (22.8 +/- 2.4 yr. old) estimates of sagittal plane elbow angle and angular velocity of elbow flexion visually was performed. 42 subjects rated videotape replays of 30 movements organized into three speeds of movement and two criterion elbow angles. Video images of the movements were analyzed with Peak Motus to measure actual values of elbow angles and peak angular velocity. Of the subjects 85.7% had speed ratings significantly correlated with true peak elbow angular velocity in all three angular velocity conditions. Few (16.7%) subjects' ratings of elbow angle correlated significantly with actual angles. Analysis of the subjects with good ratings showed the accuracy of visual ratings was significantly related to speed, with decreasing accuracy for slower speeds of movement. The use of criterion movements did not improve the small percentage of novice observers who could accurately estimate body angles during movement. PMID:16060418
Modified maximum tangential stress criterion for fracture behavior of zirconia/veneer interfaces.
Mirsayar, M M; Park, P
2016-06-01
The veneering porcelain sintered on zirconia is widely used in dental prostheses, but repeated mechanical loadings may cause a fracture such as edge chipping or delamination. In order to predict the crack initiation angle and fracture toughness of zirconia/veneer bi-layered components subjected to mixed mode loadings, the accuracy of a new and traditional fracture criteria are investigated. A modified maximum tangential stress criterion considering the effect of T-stress and critical distance theory is introduced, and compared to three traditional fracture criteria. Comparisons to the recently published fracture test data show that the traditional fracture criteria are not able to properly predict the fracture initiation conditions in zirconia/veneer bi-material joints. The modified maximum tangential stress criterion provides more accurate predictions of the experimental results than the traditional fracture criteria. PMID:26807673
Threshold Determining for MinabsLLR Stopping Criterion for Turbo Codes
NASA Astrophysics Data System (ADS)
Trifina, Lucian; Tărniceriu, Daniela; Baltă, Horia
2013-09-01
The paper proposes a method to determine the threshold for the iteration stopping criterion based on minimum absolute values of Logarithm Likelihood Ratios (minabsLLR), for turbo codes. The method is based on the simulation of a small number of frames at the signal-to-noise ratio (SNR) wanted for Genie stopper benchmark criterion and the use of a constant, deduced from simulations, which depends on the approximate frame error rate (FER). We used the least squares approximation to provide a formula for the threshold, which depends linearly on SNR. For a representative set of lengths, the coefficients of the previous approximation are also approximated by a linear function, using the least squares method. This approximation depends linearly on interleaver length. By using the proposed method, the number of iterations is reduced up to 3 for small and medium SNRs.
How Different is Different? Criterion and Sensitivity in Face-Space
Hill, Harold; Claes, Peter; Corcoran, Michelle; Walters, Mark; Johnston, Alan; Clement, John Gerald
2011-01-01
Not all detectable differences between face images correspond to a change in identity. Here we measure both sensitivity to change and the criterion difference that is perceived as a change in identity. Both measures are used to test between possible similarity metrics. Using a same/different task and the method of constant stimuli criterion is specified as the 50% “different” point (P50) and sensitivity as the difference limen (DL). Stimuli and differences are defined within a “face-space” based on principal components analysis of measured differences in three-dimensional shape. In Experiment 1 we varied views available. Criterion (P50) was lowest for identical full-face view comparisons that can be based on image differences. When comparing across views P50, was the same for a static 45° change as for multiple animated views, although sensitivity (DL) was higher for the animated case, where it was as high as for identical views. Experiments 2 and 3 tested possible similarity metrics. Experiment 2 contrasted Euclidean and Mahalanobis distance by setting PC1 or PC2 to zero. DL did not differ between conditions consistent with Mahalanobis. P50 was lower when PC2 changed emphasizing that perceived changes in identity are not determined by the magnitude of Euclidean physical differences. Experiment 3 contrasted a distance with an angle based similarity measure. We varied the distinctiveness of the faces being compared by varying distance from the origin, a manipulation that affects distances but not angles between faces. Angular P50 and DL were both constant for faces from 1 to 2 SD from the mean, consistent with an angular measure. We conclude that both criterion and sensitivity need to be considered and that an angular similarity metric based on standardized PC values provides the best metric for specifying what physical differences will be perceived to change in identity. PMID:21738516
Miyashita, Noe; Tanaka, Makoto; Gotoda, Ryusuke
2015-01-01
The application of rapid microbiological methods (RMM) to bacterial monitoring in pharmaceutical manufacturing processes is now a key topic, since timely microbiological data are critical for product release, continuous process improvement and quality control. An automated, highly sensitive detection system has been developed which can measure the amount of ATP in a sample in 2 h with one hundredfold more sensitive than the conventional ATP method. One of the major subjects for adoption and implementation of RMM is how to set the criterion value for practical microbial control. This value was conventionally been set by experimental rule and indicated as the number of colonies counted after incubation in a particular medium. We have adopted a new approach to set a criterion value which enables assessment in whether the status of the object is normal or not. By setting this criterion value, it is possible to conduct the microbiological control with the intended probability of false-positive and false-negative. In this approach the probability distribution model of the measurement value of each object in a normal status has been established by performing repetitive measurement of each object. We have suggested and verified the probability distribution form of the ATP measurement value using measurement data of the standard bacterial solution of Staphylococcus aureus. The theoretical value of the model was in good agreement with the actual measured value. The results suggest it is possible to set an applicable management criterion value using this model and to conduct new microbiological monitoring using RMM. PMID:26521822
NASA Astrophysics Data System (ADS)
Lazar, A.; Stegner, A.; Heifetz, E.
2012-04-01
The stability of axisymmetric oceanic-like vortices to inertial perturbations is investigated by means of linear stability analysis, taking into account the thickness and the stratification of the thermocline, as well as the vertical eddy viscosity. The model considers different types of circular barotropic vortices in a linearly stratified shallow layer confined with rigid lids. In this case the aspect ratio (thermocline height to vortex radius ratio) should be added to the parameters that control the stability for columnar vortices, which are the stratification, and the Ekman and Rossby numbers. We show that for strong stratification the Burger number (the radius of the vortex in relation to the Rossby radius of deformation) replaces the aspect ratio and the stratification parameter, and then only three parameters are needed. Numerical analysis reveals that if the intensity of the vortex is characterized by the vortex Rossby number, then for monotonic and non-isolated vortices, the instability is not sensitive to the vorticity profile. This allows extending our analytical solutions for the Rankine vortex to a wide variety of oceanic cases, including results such as the analytic dispersion relation, and the marginal stability criterion. This criterion suits oceanic conditions better than the generalized Rayleigh criterion, which is only valid for non-dissipative and non-stratified eddies. Comparison with literature oceanographic data shows that our criterion allows for cases that seem to contradict the common oceanographic hypothesis for inertial instability: 1. Intense submesoscale anticyclones may be stable even with a core region of negative absolute vorticity; and on the other hand, 2. mesoscale vortices can be unstable. We corroborate our findings with large-scale laboratory experiments, performed at the LEGI-Coriolis platform.
ERIC Educational Resources Information Center
Harms, Robert A.
Based on John Rawls' theory of justice as fairness, a nine-item rating scale was developed to serve as a criterion in studies of test item bias. Two principles underlie the scale: (1) Within a defined usage, test items should not affect students so that they are unable to do as well as their abilities would indicate; and (2) within the domain of a…
A termination criterion for parameter estimation in stochastic models in systems biology.
Zimmer, Christoph; Sahle, Sven
2015-11-01
Parameter estimation procedures are a central aspect of modeling approaches in systems biology. They are often computationally expensive, especially when the models take stochasticity into account. Typically parameter estimation involves the iterative optimization of an objective function that describes how well the model fits some measured data with a certain set of parameter values. In order to limit the computational expenses it is therefore important to apply an adequate stopping criterion for the optimization process, so that the optimization continues at least until a reasonable fit is obtained, but not much longer. In the case of stochastic modeling, at least some parameter estimation schemes involve an objective function that is itself a random variable. This means that plain convergence tests are not a priori suitable as stopping criteria. This article suggests a termination criterion suited to optimization problems in parameter estimation arising from stochastic models in systems biology. The termination criterion is developed for optimization algorithms that involve populations of parameter sets, such as particle swarm or evolutionary algorithms. It is based on comparing the variance of the objective function over the whole population of parameter sets with the variance of repeated evaluations of the objective function at the best parameter set. The performance is demonstrated for several different algorithms. To test the termination criterion we choose polynomial test functions as well as systems biology models such as an Immigration-Death model and a bistable genetic toggle switch. The genetic toggle switch is an especially challenging test case as it shows a stochastic switching between two steady states which is qualitatively different from the model behavior in a deterministic model. PMID:26360409
Fatigue acceptance test limit criterion for larger diameter rolled thread fasteners
Kephart, A.R.
1997-05-01
This document describes a fatigue lifetime acceptance test criterion by which studs having rolled threads, larger than 1.0 inches in diameter, can be assured to meet minimum quality attributes associated with a controlled rolling process. This criterion is derived from a stress dependent, room temperature air fatigue database for test studs having a 0.625 inch diameter threads of Alloys X-750 HTH and direct aged 625. Anticipated fatigue lives of larger threads are based on thread root elastic stress concentration factors which increase with increasing thread diameters. Over the thread size range of interest, a 30% increase in notch stress is equivalent to a factor of five (5X) reduction in fatigue life. The resulting diameter dependent fatigue acceptance criterion is normalized to the aerospace rolled thread acceptance standards for a 1.0 inch diameter, 0.125 inch pitch, Unified National thread with a controlled Root radius (UNR). Testing was conducted at a stress of 50% of the minimum specified material ultimate strength, 80 Ksi, and at a stress ratio (R) of 0.10. Limited test data for fastener diameters of 1.00 to 2.25 inches are compared to the acceptance criterion. Sensitivity of fatigue life of threads to test nut geometry variables was also shown to be dependent on notch stress conditions. Bearing surface concavity of the compression nuts and thread flank contact mismatch conditions can significantly affect the fastener fatigue life. Without improved controls these conditions could potentially provide misleading acceptance data. Alternate test nut geometry features are described and implemented in the rolled thread stud specification, MIL-DTL-24789(SH), to mitigate the potential effects on fatigue acceptance data.
Using the ENF Criterion for Determining the Time of Recording of Short Digital Audio Recordings
NASA Astrophysics Data System (ADS)
Huijbregtse, Maarten; Geradts, Zeno
The Electric Network Frequency (ENF) Criterion is a recently developed forensic technique for determining the time of recording of digital audio recordings, by matching the ENF pattern from a questioned recording with an ENF pattern database. In this paper we discuss its inherent limitations in the case of short - i.e., less than 10 minutes in duration - digital audio recordings. We also present a matching procedure based on the correlation coefficient, as a more robust alternative to squared error matching.
Ignition criterion and safety prediction of explosives under low velocity impact
NASA Astrophysics Data System (ADS)
Ma, Danzhu; Chen, Pengwan; Zhou, Qiang; Dai, Kaida
2013-09-01
Due to the complexity of impact-induced reaction, it is difficult to predict and evaluate the ignition and safety of explosives under low velocity impact. Plastic deformation is very important to explosive ignition under impact loading. At low strain rates, plastic deformation can be treated as an isothermal process. The deformation under high-strain-rate is usually seen as an adiabatic process, and the deformation work is transformed into heat with the attendant temperature increase of the explosive. In this paper, we proposed an ignition criterion in terms of effective plastic work and specific plastic power to predict the ignition of explosives under low velocity impact. The plastic work begins to accumulate, when the specific plastic power (i.e., the plastic strain rate) in a local region meets a threshold value; and when the plastic work is sufficient enough, the ignition occurs. The criterion parameters are determined by numerical simulation using LS-DYNA. Numerical simulation is compared with experimental data in order to calibrate the numerical model. The threshold values of this ignition criterion for different configurations are determined. In order to evaluate the validity of the criterion, the predictions of the ignition time, ignition zone, threshold velocities in Steven test with different PBX size designs and various projectiles, as well as the ignition threshold conditions in a modified drop weight test, Susan test, and Spigot test, are carried out. The predicted results show a good agreement with experimental results, and the errors of the ignition threshold are less than 15% for all the experimental configurations.
Solonick, W.
1996-11-01
Rapidly applied transient dynamic loads produce stresses and deflections in structures that typically exceed those from static loading conditions. Previous acceptance criteria for structures designed for rapidly applied transient dynamic loading limited stresses to those determined from elastic analysis. Different stress limits were established for different grades of structure depending upon the amount of permanent set considered acceptable. Structure allowed to sustain very limited permanent set is designed to stress limits not significantly greater than yield stress. Greater permanent set in structure under rapidly applied transient dynamic loading conditions is permitted by establishing stress limits that are significantly greater than yield stress but still provide adequate safety margin (with respect to failure). This paper presents a strain-based elastic-plastic (i.e., inelastic) analysis criterion developed as an alternative to the more conservative stress-based elastic analysis stress criterion for structures subjected to rapidly applied transient dynamic loading. The strain limits established are based on a fraction of the strain at ultimate stress obtained from an engineering stress/strain curve of the material. Strains limits are categorized by type as membrane or surface and by region as general, local, or concentrated. The application of the elastic-plastic criterion provides a more accurate, less conservative design/analysis basis for structures than that used in elastic stress-based analysis criteria, while still providing adequate safety margins.
On a Criterion for Simultaneous Block-Diagonalization of Normal Matrices
NASA Astrophysics Data System (ADS)
Pastuszak, G.; Kamizawa, T.; Jamiołkowski, A.
2016-03-01
Assume that A1, … , As are complex normal n × n matrices, p is a natural number and S2p is the standard polynomial in 2p non-commutative variables. It follows from classical results of S. Amitsur, J. Levitzki and H. Shapiro that A1, … , As can be simultaneously block-diagonalized by a unitary matrix with blocks of sizes not greater than p if and only if the algebra generated by A1, … , As satisfies the polynomial identity S2p = 0. We call this theorem the ALS-criterion for simultaneous block-diagonalization of normal matrices. In this paper, we present some application of the ALS-criterion in quantum theory. Namely, we give another proof of the renowned Morris-Shore transformation. Moreover, we discuss computable versions of the ALS-criterion. These versions allow one to verify the condition S2p = 0 in a finite number of steps. Such an approach is more useful in practical applications than the original one.
Stellar evolution at high mass with semiconvective mixing according to the Schwarzschild criterion
NASA Technical Reports Server (NTRS)
Stothers, R.; Chin, C.-W.
1976-01-01
Evolutionary sequences for stellar models with 10, 15, 30, and 60 solar masses, as well as four different initial chemical compositions, are calculated to the end of core helium burning using the Schwarzschild criterion for convection. The results are analyzed in terms of the modifications of interior structure and surface parameters induced by semiconvective mixing as a result of adopting the Schwarzschild criterion. It is found that the main differences from results based on the Ledoux criterion are the great extent of the convectively unstable layers in the intermediate zone and the eventual development of a fully convective zone at the base of the semiconvective one. It is shown that semiconvection develops outside the convective core just after the ZAMS stage for masses greater than 12 solar masses and just before the stage of central hydrogen exhaustion for masses greater than 6 solar masses. The present models are found to be insufficiently hot in comparison with the bulk of observed stable blue supergiants and to predict far too many red supergiants fro the range above 20 solar masses. It is concluded that something is fundamentally wrong with the models, the most likely suspects being the stellar opacities adopted and the neglect of mass loss.
NASA Astrophysics Data System (ADS)
Lazar, Ayah; Stegner, Alexandre; Heifetz, Eyal
2012-11-01
Inertial instability is a possible mechanism for vertical mixing in the submesoscale ocean. The stability of axisymmetric oceanic-like vortices to inertial perturbations is investigated by linear stability analysis, taking into account the thickness and the stratification of the thermocline, as well as the vertical eddy viscosity. Numerical analysis reveals that the instability is insensitive to the vorticity profile if the intensity of the vortex is characterized by the vortex Rossby number (instead of the local normalized vorticity). This allows extending our analytical solutions for the Rankine vortex to a wide variety of oceanic cases, including results such as the analytic dispersion relation, and the marginal stability criterion. This suits oceanic conditions better than the widely used generalized Rayleigh criterion. Comparison with oceanographic data shows that our criterion permits cases that contradict the common oceanographic hypothesis for inertial instability. For instance, intense submesoscale anticyclones may be stable even with a core region of negative absolute vorticity. We corroborate our findings with large-scale laboratory experiments and find a signature of the instability on the mean-flow, which could be used in future oceanographic measurements.
[Scarcity in health care, age as selection criterion and the value of old age. Current discussion].
Naafs, J
1993-06-01
There is a growing attention for setting limits in health care. Contemporary medical scarcity makes choices necessary, but what are the arguments? Only medical criteria for selection are accepted in the Netherlands, but that does not mean at all that age is an unimportant criterion. In this article the discussion on age as criterion for selection is reviewed. It seems that arguments are based on different basic (moral) assumptions and that age and aging can be appreciated from different points of view. There is among other things the principle of justice and the idea of a natural life-span (Daniels), the norm of a worthwhile life-time (the fair-innings argument of Harris) and the idea of old age as a period of its own (Callahan). The different starting points can lead to the same way of thinking about age as a criterion for selection. Daniels, Harris, and Callahan justify this kind of selection. The Dunning-committee however does not accept it, from the point of a fundamental equality of people, the protection of life and the principle of solidarity in our society. It seems that not only the different arguments lead towards different conclusions but also the different views on the value of old age by different groups or by society as a whole. PMID:8328008
Evidence for the criterion validity and clinical utility of the Pathological Narcissism Inventory
Thomas, Katherine M.; Wright, Aidan G.C.; Lukowitsky, Mark R.; Donnellan, M. Brent; Hopwood, Christopher J.
2012-01-01
In this study we evaluated aspects of criterion validity and clinical utility of the grandiosity and vulnerability components of the Pathological Narcissism Inventory (PNI) using two undergraduate samples (Ns = 299, 500). Criterion validity was assessed by evaluating the correlations of narcissistic grandiosity and narcissistic vulnerability with established indices of normal personality traits, psychopathology and clinical concerns, and pathological personality traits. Overall, the pattern of correlations supported the convergent and discriminate validity of grandiose and vulnerable conceptualizations of pathological narcissism as measured by the PNI. Clinical utility was assessed by evaluating the extent to which clinicians without specific training in pathological narcissism as well as clinicians with expertise in pathological narcissism could accurately predict the correlates of PNI grandiosity and vulnerability with normal and pathological personality traits and psychopathology. The rcontrast-cv coefficient (Westen & Rosenthal, 2003) provided a global index of accuracy in clinicians’ predictions that was more fully elaborated by examining systematic discrepancies across groups. Overall, novice and expert clinicians were generally able to predict criterion correlations, with some exceptions (e.g., counter to predictions, pathological narcissism was negatively associated with treatment resistance). These results provide further evidence regarding the validity and utility of the narcissistic grandiosity and narcissistic vulnerability constructs as measured by the PNI. PMID:22315481
Metacognitive monitoring during criterion learning: when and why are judgments accurate?
Pyc, Mary A; Rawson, Katherine A; Aschenbrenner, Andrew J
2014-08-01
Research on metacognitive judgment accuracy during retrieval practice has increased in recent years. However, prior work had not systematically evaluated item-level judgment accuracy and the underlying bases of judgment accuracy in a criterion-learning paradigm (in which items are practiced until correctly recalled during encoding). Understanding these relationships during criterion learning has important theoretical implications for self-regulated learning frameworks, and also has applied implications for student learning: If the factors that influence metacognitive judgments are not predictive of subsequent test performance, students may make poor decisions during self-regulated learning. In the present experiments, participants engaged in test-restudy practice until items were recalled correctly. Once a given item reached criterion, participants made an immediate or delayed judgment of learning (JOL) for the item. A final cued-recall test occurred 30 min later. We examined judgment accuracy (the relationship between JOLs and test performance) and the underlying bases of judgment accuracy by evaluating cue utilization (the relationship between cues and JOLs) and cue diagnosticity (the relationship between cues and test performance). Immediate JOLs were only modestly related to subsequent test performance, and further analyses revealed that the cues related to JOLs were only weakly predictive of test accuracy. However, delaying JOLs improved both the accuracy of the JOLs and the diagnosticity of the cues that influenced judgments. PMID:24643790
Lyapunov Exponent Criterion for Stability of Planetary Orbits in Binary Systems
NASA Astrophysics Data System (ADS)
Musielak, Zdzislaw E.; Quarles, B.; Eberle, J.; Cuntz, M.
2011-01-01
The existence of planets in stellar binary systems is now well-confirmed by many observations. Stability of planetary orbits in these systems has extensively been studied and some attempts have been made to establish stringent stability criteria for the orbits. In this paper, we contribute to the ongoing work on the stability criteria in binary systems by introducing a Lyapunov exponent criterion. We have computed the Lyapunov exponents, the Lyapunov dimension and the time series spectra for planets in binary system. 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 to the parameter space, which covers mass and distance ratios for the considered binary systems, we determined regions of stability and used the time series spectra and the Lyapunov dimension to illustrate the reasons behind the stability. Specific applications of the criterion to binary systems with known planets will also be discussed.
The universal criterion for switching a magnetic vortex core in soft magnetic nanodots
Lee, K.-S.; Kim, S.-K.; Yu, Y.-S.; Choi, Y.-S.; Guslienko, K. Y.; Jung, H.; Fischer, P.
2008-10-01
The universal criterion for ultrafast vortex core switching between core-up and -down vortex bi-states in soft magnetic nanodots was empirically investigated by micromagnetic simulations and combined with an analytical approach. Vortex-core switching occurs whenever the velocity of vortex core motion reaches a critical value, which is {nu}{sub c} = 330 {+-} 37 m/s for Permalloy, as estimated from numerical simulations. This critical velocity was found to be {nu}{sub c} = {eta}{sub c}{gamma} {radical}A{sub ex} with A{sub ex} the exchange stiffness, {gamma} the gyromagnetic ratio, and an estimated proportional constant {eta}{sub c} = 1.66 {+-} 0.18. This criterion does neither depend on driving force parameters nor on the dimension or geometry of the magnetic specimen. The phase diagrams for the vortex core switching criterion and its switching time with respect to both the strength and angular frequency of circular rotating magnetic fields were derived, which offer practical guidance for implementing vortex core switching into future solid state information storage devices.
The effect of suspended particles on Jean's criterion for gravitational instability
NASA Technical Reports Server (NTRS)
Wollkind, David J.; Yates, Kemble R.
1990-01-01
The effect that the proper inclusion of suspended particles has on Jeans' criterion for the self-gravitational instability of an unbounded nonrotating adiabatic gas cloud is examined by formulating the appropriate model system, introducing particular physically plausible equations of state and constitutive relations, performing a linear stability analysis of a uniformly expanding exact solution to these governing equations, and exploiting the fact that there exists a natural small material parameter for this problem given by N sub 1/n sub 1, the ratio of the initial number density for the particles to that for the gas. The main result of this investigation is the derivation of an altered criterion which can substantially reduce Jeans' original critical wavelength for instability. It is then shown that the existing discrepancy between Jeans' theoretical prediction using and actual observational data relevant to the Andromeda nebula M31 can be accounted for by this new criterion of assuming suspended particles of a reasonable grain size and distribution to be present.
Applications of ENF criterion in forensic audio, video, computer and telecommunication analysis.
Grigoras, Catalin
2007-04-11
This article reports on the electric network frequency criterion as a means of assessing the integrity of digital audio/video evidence and forensic IT and telecommunication analysis. A brief description is given to different ENF types and phenomena that determine ENF variations. In most situations, to reach a non-authenticity opinion, the visual inspection of spectrograms and comparison with an ENF database are enough. A more detailed investigation, in the time domain, requires short time windows measurements and analyses. The stability of the ENF over geographical distances has been established by comparison of synchronized recordings made at different locations on the same network. Real cases are presented, in which the ENF criterion was used to investigate audio and video files created with secret surveillance systems, a digitized audio/video recording and a TV broadcasted reportage. By applying the ENF Criterion in forensic audio/video analysis, one can determine whether and where a digital recording has been edited, establish whether it was made at the time claimed, and identify the time and date of the registering operation. PMID:16884872
Evaluation of the aromaticity of non-planar and bowl-shaped molecules by NICS criterion.
Reisi-Vanani, Adel; Rezaei, Ali Asghar
2015-09-01
Nucleus independent chemical shift (NICS) criterion was used to gauge the amount of aromaticity in a lot of publications in two last decades. Non-planar molecules with many polygons in different sheets that make angle together have not been studied by this criterion. Perhaps, one ascribes this deficiency to NICS index, but we think it is concern to depauperation in evaluation methods. Therefore, in this work, we try to evaluate aromaticity of two fullerene substructures bowl-shaped molecules, namely corannulene and sumanene as typical non-planar molecules by using of the NICSzz-scan method. The gauge-independent atomic orbital (GIAO) NMR calculations were done at B3LYP/6-311+G(d) level of theory. Energetic criterion as another tool for evaluation of the aromaticity of compounds was used and discussed. Results shows that pentagon and hexagon rings in corannulene have antiaromatic and aromatic character, respectively and in sumanene, pentagon and outer hexagon rings have antiaromatic and aromatic character, respectively. However, the picture obtained based on the NICS computations did not provide any insight towards the real nature of current density in the corannulene and sumanene. PMID:26188797
Hicks, Jason L; Starns, Jeffrey J
2014-07-01
In seven experiments, we explored the potential for strength-based, within-list criterion shifts in recognition memory. People studied a mix of target words, some presented four times (strong) and others studied once (weak). In Experiments 1, 2, 4A, and 4B, the test was organized into alternating blocks of 10, 20, or 40 trials. Each block contained lures intermixed with strong targets only or weak targets only. In strength-cued conditions, test probes appeared in a unique font color for strong and weak blocks. In the uncued conditions of Experiments 1 and 2, similar strength blocks were tested, but strength was not cued with font color. False alarms to lures were lower in blocks containing strong target words, as compared with lures in blocks containing weak targets, but only when strength was cued with font color. Providing test feedback in Experiment 2 did not alter these results. In Experiments 3A-3C, test items were presented in a random order (i.e., not blocked by strength). Of these three experiments, only one demonstrated a significant shift even though strength cues were provided. Overall, the criterion shift was larger and more reliable as block size increased, and the shift occurred only when strength was cued with font color. These results clarify the factors that affect participants' willingness to change their response criterion within a test list. PMID:24523046
NASA Astrophysics Data System (ADS)
Van Mieghem, P.; van de Bovenkamp, R.
2015-03-01
Mean-field approximations (MFAs) are frequently used in physics. When a process (such as an epidemic or a synchronization) on a network is approximated by MFA, a major hurdle is the determination of those graphs for which MFA is reasonably accurate. Here, we present an accuracy criterion for Markovian susceptible-infected-susceptible (SIS) epidemics on any network, based on the spectrum of the adjacency and SIS covariance matrix. We evaluate the MFA criterion for the complete and star graphs analytically, and numerically for connected Erdős-Rényi random graphs for small size N ≤14 . The accuracy of MFA increases with average degree and with N . Precise simulations (up to network sizes N =100 ) of the MFA accuracy criterion versus N for the complete graph, star, square lattice, and path graphs lead us to conjecture that the worst MFA accuracy decreases, for large N , proportionally to the inverse of the spectral radius of the adjacency matrix of the graph.
Experiments and modeling of ballistic penetration using an energy failure criterion
NASA Astrophysics Data System (ADS)
Dolinski, M.; Rittel, D.
2015-10-01
One of the most intricate problems in terminal ballistics is the physics underlying penetration and perforation. Several penetration modes are well identified, such as petalling, plugging, spall failure and fragmentation (Sedgwick, 1968). In most cases, the final target failure will combine those modes. Some of the failure modes can be due to brittle material behavior, but penetration of ductile targets by blunt projectiles, involving plugging in particular, is caused by excessive localized plasticity, with emphasis on adiabatic shear banding (ASB). Among the theories regarding the onset of ASB, new evidence was recently brought by Rittel et al. (2006), according to whom shear bands initiate as a result of dynamic recrystallization (DRX), a local softening mechanism driven by the stored energy of cold work. As such, ASB formation results from microstructural transformations, rather than from thermal softening. In our previous work (Dolinski et al., 2010), a failure criterion based on plastic strain energy density was presented and applied to model four different classical examples of dynamic failure involving ASB formation. According to this criterion, a material point starts to fail when the total plastic strain energy density reaches a critical value. Thereafter, the strength of the element decreases gradually to zero to mimic the actual material mechanical behavior. The goal of this paper is to present a new combined experimental-numerical study of ballistic penetration and perforation, using the above-mentioned failure criterion. Careful experiments are carried out using a single combination of AISI 4340 FSP projectiles and 25[mm] thick RHA steel plates, while the impact velocity, and hence the imparted damage, are systematically varied. We show that our failure model, which includes only one adjustable parameter in this present work, can faithfully reproduce each of the experiments without any further adjustment. Moreover, it is shown that the most common
Experiments and modeling of ballistic penetration using an energy failure criterion
NASA Astrophysics Data System (ADS)
Dolinski, M.; Rittel, D.
2015-09-01
One of the most intricate problems in terminal ballistics is the physics underlying penetration and perforation. Several penetration modes are well identified, such as petalling, plugging, spall failure and fragmentation (Sedgwick, 1968). In most cases, the final target failure will combine those modes. Some of the failure modes can be due to brittle material behavior, but penetration of ductile targets by blunt projectiles, involving plugging in particular, is caused by excessive localized plasticity, with emphasis on adiabatic shear banding (ASB). Among the theories regarding the onset of ASB, new evidence was recently brought by Rittel et al. (2006), according to whom shear bands initiate as a result of dynamic recrystallization (DRX), a local softening mechanism driven by the stored energy of cold work. As such, ASB formation results from microstructural transformations, rather than from thermal softening. In our previous work (Dolinski et al., 2010), a failure criterion based on plastic strain energy density was presented and applied to model four different classical examples of dynamic failure involving ASB formation. According to this criterion, a material point starts to fail when the total plastic strain energy density reaches a critical value. Thereafter, the strength of the element decreases gradually to zero to mimic the actual material mechanical behavior. The goal of this paper is to present a new combined experimental-numerical study of ballistic penetration and perforation, using the above-mentioned failure criterion. Careful experiments are carried out using a single combination of AISI 4340 FSP projectiles and 25[mm] thick RHA steel plates, while the impact velocity, and hence the imparted damage, are systematically varied. We show that our failure model, which includes only one adjustable parameter in this present work, can faithfully reproduce each of the experiments without any further adjustment. Moreover, it is shown that the most common
NASA Astrophysics Data System (ADS)
Shin, Hyunho; Lee, Hun-Joo; Yoo, Yo-Han; Lee, Woong
A determination procedure for element elimination criterion in finite element simulation of high-strain-rate impact and penetration phenomena, occurring between tungsten heavy alloy long-rod penetrators and steel targets, has been presented with some demonstrations for the validity of the established criterion. The element elimination criterion for the two types of materials have been determined by comparing the simulated depth of penetration (DOP) and deformed shape of the penetrator with previously available experimental results. Although the criterion affects the simulated DOP significantly at the studied impact velocity of 1500m/s, once established, they are shown to be valid in predicting the DOP in the impact velocity range between 1100 and 1750m/s. The events of partial penetration with severe material deformation such as critical ricochet angle and ricochet phenomenology have also been successfully predicted using the established criterion in the similar impact velocity range. Thus it is suggested that the determination procedure for the suitable element erosion criterion is prerequisite in simulating high-strain-rate impact/penetration phenomena and the criterion established by the procedure is useful in fairly broad range of the velocity and for other similar high-strain-rate events.
NASA Astrophysics Data System (ADS)
Kotchasarn, Chirawat; Saengudomlert, Poompat
We investigate the problem of joint transmitter and receiver power allocation with the minimax mean square error (MSE) criterion for uplink transmissions in a multi-carrier code division multiple access (MC-CDMA) system. The objective of power allocation is to minimize the maximum MSE among all users each of which has limited transmit power. This problem is a nonlinear optimization problem. Using the Lagrange multiplier method, we derive the Karush-Kuhn-Tucker (KKT) conditions which are necessary for a power allocation to be optimal. Numerical results indicate that, compared to the minimum total MSE criterion, the minimax MSE criterion yields a higher total MSE but provides a fairer treatment across the users. The advantages of the minimax MSE criterion are more evident when we consider the bit error rate (BER) estimates. Numerical results show that the minimax MSE criterion yields a lower maximum BER and a lower average BER. We also observe that, with the minimax MSE criterion, some users do not transmit at full power. For comparison, with the minimum total MSE criterion, all users transmit at full power. In addition, we investigate robust joint transmitter and receiver power allocation where the channel state information (CSI) is not perfect. The CSI error is assumed to be unknown but bounded by a deterministic value. This problem is formulated as a semidefinite programming (SDP) problem with bilinear matrix inequality (BMI) constraints. Numerical results show that, with imperfect CSI, the minimax MSE criterion also outperforms the minimum total MSE criterion in terms of the maximum and average BERs.
NASA Astrophysics Data System (ADS)
Haimson, Bezalel; Chang, Chandong; Ma, Xiaodong
2016-04-01
The UW true triaxial testing system enables the application of independent compressive loads to cuboidal specimens (19×19×38 mm) along three principal directions. We used the apparatus to conduct extensive series of experiments in three crystalline rocks (Westerly granite, KTB amphibolite, and SAFOD granodiorite) and three clastic rocks of different porosities [TCDP siltstone (7%), Coconino sandstone (17%), and Bentheim sandstone (24%)]. For each rock, several magnitudes of σ3 were employed, between 0 MPa and 100-160 MPa, and for every σ3, σ2 was varied from test to test between σ2 = σ3 and σ2=(0.4 to 1.0) σ1.Testing consisted of keeping σ2and σ3constant, and raising σ1to failure (σ1,peak). The results, plotted as σ1,peakvs. σ2for each σ3 used, highlight the undeniable effect of σ2on the compressive failure of rocks. For each level of σ3, the lowest σ2 tested (σ2 = σ3) yielded the data point used for conventional-triaxial failure criterion. However, for the same σ3 and depending on σ2 magnitude, the maximum stress bringing about failure (σ1,peak) may be considerably higher, by as much as 50% in crystalline rocks, or 15% in clastic rocks, over that in a conventional triaxial test. An important consequence is that use of a Mohr-type criterion leads to overly conservative predictions of failure. The true triaxial test results demonstrate that a criterion in terms of all (three principal stresses is necessary to characterize failure. Thus, we propose a 'Generalized Nadai Criterion' (GNC) based on Nadai (1950), i.e. expressed in terms of the two stress invariants at failure (f), τoct,f = βσoct,f, where τoct,f = 1/3[(σ1,peak ‑σ2)2+(σ2 ‑σ3)2+(σ3 ‑σ1,peak)2]0.5 and σoct,f = (σ1,peak + σ2 + σ3)/3, and β is a function that varies from rock to rock. Moreover, the criterion depends also on the relative magnitude of σ2, represented by a parameter b [= (σ2 - σ3)/(σ1,peak - σ3)]. For each octahedral shear stress at failure (
Cooper, Sheri L; Pelly, Fiona E; Lowe, John B
2016-05-01
Nutrient profiling (NP) is defined as the science of ranking foods according to their nutritional composition for the purpose of preventing disease or promoting health. The application of NP is ultimately to assist consumers to make healthier food choices, and thus provide a cost effective public health strategy to reduce the incidence of diet-related chronic disease. To our knowledge, no review has assessed the evidence to confirm the validity of NP models. We conducted a systematic review to investigate the construct and criterion-related validity of NP models in ranking food according to their nutritional composition for the purpose of preventing disease and promoting health. We searched peer-reviewed research published to 30 June 2015 and used PUBMED, Global Health (CABI), and SCOPUS databases. Within study bias was assessed using an adapted version of the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies -2) tool for all diagnostic studies and the Cochrane Collaboration's Risk of Bias tool for all non-diagnostic studies. The GRADE (Grades of Recommendation, Assessment, Development, and Evaluation) approach was used to guide our judgement of the quality of the body of evidence for each outcome measure. From a total of 83 studies, 69 confirmed the construct validity of NP models; however most of these studies contained methodological weaknesses. Six studies used objective external measures to confirm the criterion-related validity of NP models; which inherently improved quality. The overall quality of evidence on the accuracy of NP models was judged to be very low to moderate using the GRADE approach. Many carefully designed studies to establish both construct and criterion-related validity are necessary to authenticate the application of NP models and provide the evidence to support the current definition of NP. PMID:26850312
Baumgartner, S.; Bieli, R.; Bergmann, U. C.
2012-07-01
An overview is given of existing CPR design criteria and the methods used in BWR reload analysis to evaluate the impact of channel bow on CPR margins. Potential weaknesses in today's methodologies are discussed. Westinghouse in collaboration with KKL and Axpo - operator and owner of the Leibstadt NPP - has developed an optimized CPR methodology based on a new criterion to protect against dryout during normal operation and with a more rigorous treatment of channel bow. The new steady-state criterion is expressed in terms of an upper limit of 0.01 for the dryout failure probability per year. This is considered a meaningful and appropriate criterion that can be directly related to the probabilistic criteria set-up for the analyses of Anticipated Operation Occurrences (AOOs) and accidents. In the Monte Carlo approach a statistical modeling of channel bow and an accurate evaluation of CPR response functions allow the associated CPR penalties to be included directly in the plant SLMCPR and OLMCPR in a best-estimate manner. In this way, the treatment of channel bow is equivalent to all other uncertainties affecting CPR. Emphasis is put on quantifying the statistical distribution of channel bow throughout the core using measurement data. The optimized CPR methodology has been implemented in the Westinghouse Monte Carlo code, McSLAP. The methodology improves the quality of dryout safety assessments by supplying more valuable information and better control of conservatisms in establishing operational limits for CPR. The methodology is demonstrated with application examples from the introduction at KKL. (authors)
NASA Astrophysics Data System (ADS)
Xiao, Si; Wang, He-Ling; Liu, Bin; Hwang, Keh-Chih
2015-11-01
The J-integral based criterion is widely used in elastic-plastic fracture mechanics. However, it is not rigorously applicable when plastic unloading appears during crack propagation. One difficulty is that the energy density with plastic unloading in the J-integral cannot be defined unambiguously. In this paper, we alternatively start from the analysis on the power balance, and propose a surface-forming energy release rate (ERR), which represents the energy available for separating the crack surfaces during the crack propagation and excludes the loading-mode-dependent plastic dissipation. Therefore the surface-forming ERR based fracture criterion has wider applicability, including elastic-plastic crack propagation problems. Several formulae are derived for calculating the surface-forming ERR. From the most concise formula, it is interesting to note that the surface-forming ERR can be computed using only the stress and deformation of the current moment, and the definition of the energy density or work density is avoided. When an infinitesimal contour is chosen, the expression can be further simplified. For any fracture behaviors, the surface-forming ERR is proven to be path-independent, and the path-independence of its constituent term, so-called Js-integral, is also investigated. The physical meanings and applicability of the proposed surface-forming ERR, traditional ERR, Js-integral and J-integral are compared and discussed. Besides, we give an interpretation of Rice paradox by comparing the cohesive fracture model and the surface-forming ERR based fracture criterion.
Martin, Donald E.K.
2014-01-01
Abstract Spaced seeds have been recently shown to not only detect more alignments, but also to give a more accurate measure of phylogenetic distances, and to provide a lower misclassification rate when used with Support Vector Machines (SVMs). We confirm by independent experiments these two results, and propose in this article to use a coverage criterion to measure the seed efficiency in both cases in order to design better seed patterns. We show first how this coverage criterion can be directly measured by a full automaton-based approach. We then illustrate how this criterion performs when compared with two other criteria frequently used, namely the single-hit and multiple-hit criteria, through correlation coefficients with the correct classification/the true distance. At the end, for alignment-free distances, we propose an extension by adopting the coverage criterion, show how it performs, and indicate how it can be efficiently computed. PMID:25393923
Fernández de Cañete, J; Barreiro, A; García-Cerezo, A; García-Moral, I
2001-01-01
A stabilization method based on the input-output conicity criterion is presented. Conventional learning algorithms are applied to adjust the controller dynamics, and robust stability of the closed-loop system is guaranteed by modifying the training patterns which yield unstable behavior. The methodology developed expands the class of nonlinear systems to be controlled using neural control schemes, so that the stabilization of a broad class of neural-network-based control systems, even with unknown dynamics, is assured. Straightforwardness in the application of this method is evident in contrast to the Lyapunov function approach. PMID:18249978
Use of a minimum-ellipse criterion in the study of ion-beam extraction systems
Keller, R.; Sherman, J.D.; Allison, P.
1985-01-01
Ion-beam extraction systems may be optimized by ray-tracing codes. As a general criterion for comparing the geometry-dependent phase-space distributions, we first calculate the minimum-area ellipse that encloses all particles of any given two-dimensional phase-space distribution. Then, the relation between ellipse area and contained beam fraction is established by systematically finding and eliminating those particles that contribute most heavily to the emittance. Prescriptions for finding the minimum ellipse and beam fractions will be presented. The minimum and rms ellipses are compared for two code-calculated distributions that represent ion-beam extraction geometries. 5 refs., 6 figs.
NASA Astrophysics Data System (ADS)
Sugihara, Shigemitsu; Shinozaki, Tsuguhiro; Ohishi, Hiroyuki; Araki, Yoshinori; Furukawa, Kohei
It is difficult to deregulate sediment-related disaster warning information, for the reason that it is difficult to quantify the risk of disaster after the heavy rain. If we can quantify the risk according to the rain situation, it will be an indication of deregulation. In this study, using logistic regression analysis, we quantified the risk according to the rain situation as the probability of disaster occurrence. And we analyzed the setup of resolutive criterion for sediment-related disaster warning information. As a result, we can improve convenience of the evaluation method of probability of disaster occurrence, which is useful to provide information of imminently situation.
Model based matching using simulated annealing and a minimum representation size criterion
NASA Technical Reports Server (NTRS)
Ravichandran, B.; Sanderson, A. C.
1992-01-01
We define the model based matching problem in terms of the correspondence and transformation that relate the model and scene, and the search and evaluation measures needed to find the best correspondence and transformation. Simulated annealing is proposed as a method for search and optimization, and the minimum representation size criterion is used as the evaluation measure in an algorithm that finds the best correspondence. An algorithm based on simulated annealing is presented and evaluated. This algorithm is viewed as a part of an adaptive, hierarchical approach which provides robust results for a variety of model based matching problems.
Effect of β on Seismic Vulnerability Curve for RC Bridge Based on Double Damage Criterion
NASA Astrophysics Data System (ADS)
Qing-hai, Feng; Wan-cheng, Yuan
2010-05-01
In the analysis of seismic vulnerability curve based on double damage criterion, the randomness of structural parameter and randomness of seismic should be considered. Firstly, the distribution characteristics of structure capability and seismic demand are obtained based on IDA and PUSHOVER, secondly, the vulnerability of the bridge is gained based on ANN and MC and a vulnerability curve according to this bridge and seismic is drawn. Finally, the analysis for a continuous bridge is displayed as an example, and parametric analysis for the effect of β is done, which reflects the bridge vulnerability overall from the point of total probability, and in order to reduce the discreteness, large value of β are suggested.
A comparison of three additive tree algorithms that rely on a least-squares loss criterion.
Smith, T J
1998-11-01
The performances of three additive tree algorithms which seek to minimize a least-squares loss criterion were compared. The algorithms included the penalty-function approach of De Soete (1983), the iterative projection strategy of Hubert & Arabie (1995) and the two-stage ADDTREE algorithm, (Corter, 1982; Sattath & Tversky, 1977). Model fit, comparability of structure, processing time and metric recovery were assessed. Results indicated that the iterative projection strategy consistently located the best-fitting tree, but also displayed a wider range and larger number of local optima. PMID:9854946
Effect of beta on Seismic Vulnerability Curve for RC Bridge Based on Double Damage Criterion
Feng Qinghai; Yuan Wancheng
2010-05-21
In the analysis of seismic vulnerability curve based on double damage criterion, the randomness of structural parameter and randomness of seismic should be considered. Firstly, the distribution characteristics of structure capability and seismic demand are obtained based on IDA and PUSHOVER, secondly, the vulnerability of the bridge is gained based on ANN and MC and a vulnerability curve according to this bridge and seismic is drawn. Finally, the analysis for a continuous bridge is displayed as an example, and parametric analysis for the effect of beta is done, which reflects the bridge vulnerability overall from the point of total probability, and in order to reduce the discreteness, large value of beta are suggested.
Learning a subspace for face image clustering via trace ratio criterion
NASA Astrophysics Data System (ADS)
Hou, Chenping; Nie, Feiping; Zhang, Changshui; Wu, Yi
2009-06-01
Face clustering is gaining ever-increasing attention due to its importance in optical image processing. Because traditional clustering methods do not specify the particular characters of the face image, they are not suitable for face image clustering. We propose a novel approach that employs the trace ratio criterion and specifies that the face images should be spatially smooth. The graph regularization technique is also applied to constrain that nearby images have similar cluster indicators. We alternately learn the optimal subspace and the clusters. Experimental results demonstrate that the proposed approach performs better than other learning methods for face image clustering.
NASA Astrophysics Data System (ADS)
Zhang, Jianling; An, Jinwen; Wang, Mina
2005-11-01
This paper describes the application and simulation of an adaptive fuzzy controller for a missile model. The fuzzy control system is tested using different values of fuzzy controller correctional factor on a nonlinear missile model. It is shown that the self-tuning fuzzy controller is well suited for controlling the pitch loop of the missile control system with air turbulence and parameter variety. The research shows that the Popov stability criterion could successfully guarantee the stability of the fuzzy system. It provides a good method for the design of missile control system. Simulation results suggest significant benefits from fuzzy logic in control task for missile pitch loop control.
A new criterion needed to evaluate reliability of digital protective relays
NASA Astrophysics Data System (ADS)
Gurevich, Vladimir
2012-11-01
There is a wide range of criteria and features for evaluating reliability in engineering; but as many as there are, only one of them has been chosen to evaluate reliability of Digital Protective Relays (DPR) in the technical documentation: Mean (operating) Time Between Failures (MTBF), which has gained universal currency and has been specified in technical manuals, information sheets, tender documentation as the key indicator of DPR reliability. But is the choice of this criterion indeed wise? The answer to this question is being sought by the author of this article.
The instability transition for the restricted 3-body problem. III. The Lyapunov exponent criterion
NASA Astrophysics Data System (ADS)
Quarles, B.; Eberle, J.; Musielak, Z. E.; Cuntz, M.
2011-09-01
Aims: We establish a criterion for the stability of planetary orbits in stellar binary systems by using Lyapunov exponents and power spectra for the special case of the circular restricted 3-body problem (CR3BP). The criterion augments our earlier results given in the two previous papers of this series where stability criteria have been developed based on the Jacobi constant and the hodograph method. Methods: The centerpiece of our method is the concept of Lyapunov exponents, which are incorporated into the analysis of orbital stability by integrating the Jacobian of the CR3BP and orthogonalizing the tangent vectors via a well-established algorithm originally developed by Wolf et al. The criterion for orbital stability based on the Lyapunov exponents is independently verified by using power spectra. The obtained results are compared to results presented in the two previous papers of this series. Results: It is shown that the maximum Lyapunov exponent can be used as an indicator for chaotic behaviour of planetary orbits, which is consistent with previous applications of this method, particularly studies for the Solar System. The chaotic behaviour corresponds to either orbital stability or instability, and it depends solely on the mass ratio μ of the binary components and the initial distance ratio ρ0 of the planet relative to the stellar separation distance. Detailed case studies are presented for μ = 0.3 and 0.5. The stability limits are characterized based on the value of the maximum Lyapunov exponent. However, chaos theory as well as the concept of Lyapunov time prevents us from predicting exactly when the planet is ejected. Our method is also able to indicate evidence of quasi-periodicity. Conclusions: For different mass ratios of the stellar components, we are able to characterize stability limits for the CR3BP based on the value of the maximum Lyapunov exponent. This theoretical result allows us to link the study of planetary orbital stability to chaos
An alternative proof of Lie's linearization theorem using a new λ -symmetry criterion
NASA Astrophysics Data System (ADS)
Al-Dweik, Ahmad Y.; Mustafa, M. T.; Mara'Beh, Raed A.; Mahomed, F. M.
2015-09-01
An alternative proof of Lie's approach for the linearization of scalar second-order ordinary differential equations is derived by using the relationship between λ -symmetries and first integrals. This relation further leads to a new λ -symmetry linearization criterion for second-order ordinary differential equations which provides a new approach for constructing the linearization transformations with lower complexity. The effectiveness of the approach is illustrated by obtaining the local linearization transformations for the linearizable nonlinear ordinary differential equations of the form y″ +F1 (x, y)y‧ + F (x, y) = 0 . Examples of linearizable nonlinear ordinary differential equations which are quadratic or cubic in the first derivative are also presented.
NASA Astrophysics Data System (ADS)
Ashworth, J. R.; Sheplev, V. S.
1997-09-01
Layered coronas between two reactant minerals can, in many cases, be attributed to diffusion-controlled growth with local equilibrium. This paper clarifies and unifies the previous approaches of various authors to the simplest form of modelling, which uses no assumed values for thermochemical quantities. A realistic overall reaction must be estimated from measured overall proportions of minerals and their major element compositions. Modelling is not restricted to a particular number of components S, relative to the number of phases Φ. IfΦ > S + 1, the overall reaction is a combination of simultaneous reactions. The stepwise method, solving for the local reaction at each boundary in turn, is extended to allow for recurrence of a mineral (its presence in two parts of the layer structure separated by a gap). The equations are also given in matrix form. A thermodynamic stability criterion is derived, determining which layer sequence is truly stable if several are computable from the same inputs. A layer structure satisfying the stability criterion has greater growth rate (and greater rate of entropy production) than the other computable layer sequences. This criterion of greatest entropy production is distinct from Prigogine's theorem of minimum entropy production, which distinguishes the stationary or quasi-stationary state from other states of the same layer sequence. The criterion leads to modification of previous results for coronas comprising hornblende, spinel, and orthopyroxene between olivine (Ol) and plagioclase (Pl). The outcome supports the previous inference that Si, and particularly Al, commonly behave as immobile relative to other cation-forming major elements. The affinity (-ΔG) of a corona-forming reaction is estimated, using previous estimates of diffusion coefficient and the duration t of reaction, together with a new model quantity (-ΔG) *. For an example of the Ol + Pl reaction, a rough calculation gives (-ΔG) > 1.7RT (per mole of P1 consumed
Resonance overlap criterion for H atom ionization by circularly polarized microwave fields
Sacha, K.; Zakrzewski, J.
1997-01-01
The threshold for H atom ionization by circularly polarized microwave fields is discussed within the classical mechanics framework for high microwave frequencies. The Chirikov resonance overlap criterion predictions are compared with estimates obtained adopting the renormalization method. It is shown that the ionization threshold is highly sensitive to the helicity of microwaves. Among all possible initial electronic orbits, those of medium eccentricity are the first to ionize. The results obtained indicate that collisions with the nucleus play a negligible role for the onset of ionization. {copyright} {ital 1997} {ital The American Physical Society}
H-atom ionization by elliptically polarized microwave fields: The overlap criterion
Sacha, K.; Zakrzewski, J.
1997-07-01
The threshold for H-atom ionization by elliptically polarized microwave fields is discussed within the classical-mechanics framework using the Chirikov overlap criterion. It is shown that the trends observed in the recent experiment [M. R. W. Bellermann {ital et al.} Phys. Rev. Lett. {bold 76}, 892 (1996)] are qualitatively reproduced by the theory; the origin of the remaining discrepancy is discussed. Increased stability of some orbits with respect to the perturbation due to the elliptically polarized microwaves has been related to vanishing widths of the corresponding resonance islands. Analytic Chirikov overlap prediction is compared with results of numerical simulations. {copyright} {ital 1997} {ital The American Physical Society}
Lerner, E. Brooke; Drendel, Amy L.; Falcone, Richard A.; Weitze, Keith C.; Badawy, Mohamed K.; Cooper, Arthur; Cushman, Jeremy T.; Drayna, Patrick C.; Gourlay, David M.; Gray, Matthew P.; Shah, Manish I.; Shah, Manish N.
2014-01-01
Background Verbal prehospital reports on an injured patient’s condition are typically used by trauma centers to determine if a trauma team should be present in the emergency department prior to patient arrival (i.e., trauma team activation). Efficacy studies of trauma team activation protocols cannot be conducted without a criterion standard definition for which pediatric patients need a trauma team activation. Objective To develop a consensus-based criterion standard definition for pediatric patients who needed the highest-level trauma team activation. Methods Ten local and national experts in emergency medicine, emergency medical services, and trauma were recruited to participate in a Modified Delphi survey process. The initial survey was populated based on outcomes that had been used in previously published literature on trauma team activation. The criterion standard definition for trauma team activation was refined iteratively based on survey responses until at least 80% agreement was achieved for each criterion. Results After five voting rounds a consensus-based definition for pediatric trauma team activation was developed. Twelve criteria were identified along with a corresponding time interval in which each criterion had to occur. The criteria include receiving specific surgery types, interventional radiology, advanced airway management, thoracostomy, blood products, spinal injury, emergency cesarean section, vasopressors, burr hole or other procedure to relieve intracranial pressure, pericardiocentesis, thoracotomy, and death in the emergency department. All expert panel members voted in all 5 voting rounds, except 1 member missed rounds 1 and 2. Each criterion had greater than 80% agreement from the panel. Conclusion A criterion standard definition for the highest-level pediatric trauma team activation was developed. This criterion standard definition will advance trauma research by allowing investigators to determine the accuracy and effectiveness of
NASA Astrophysics Data System (ADS)
Key, Christopher T.; Schumacher, Shane C.; Alexander, C. Scott
2015-09-01
This study details and demonstrates a strain-based criterion for the prediction of polymer matrix composite material damage and failure under shock loading conditions. Shock loading conditions are characterized by high-speed impacts or explosive events that result in very high pressures in the materials involved. These material pressures can reach hundreds of kbar and often exceed the material strengths by several orders of magnitude. Researchers have shown that under these high pressures, composites exhibit significant increases in stiffness and strength. In this work we summarize modifications to a previous stress based interactive failure criterion based on the model initially proposed by Hashin, to include strain dependence. The failure criterion is combined with the multi-constituent composite constitutive model (MCM) within a shock physics hydrocode. The constitutive model allows for decomposition of the composite stress and strain fields into the individual phase averaged constituent level stress and strain fields, which are then applied to the failure criterion. Numerical simulations of a metallic sphere impacting carbon/epoxy composite plates at velocities up to 1000 m/s are performed using both the stress and strain based criterion. These simulation results are compared to experimental tests to illustrate the advantages of a strain-based criterion in the shock environment.
Hardesty, Samantha L; Hagopian, Louis P; McIvor, Melissa M; Wagner, Leaora L; Sigurdsson, Sigurdur O; Bowman, Lynn G
2014-09-01
The present study isolated the effects of frequently used staff training intervention components to increase communication between direct care staff and clinicians working on an inpatient behavioral unit. Written "protocol review" quizzes developed by clinicians were designed to assess knowledge about a patient's behavioral protocols. Direct care staff completed these at the beginning of each day and evening shift. Clinicians were required to score and discuss these protocol reviews with direct care staff for at least 75% of shifts over a 2-week period. During baseline, only 21% of clinicians met this requirement. Completing and scoring of protocol reviews did not improve following additional in-service training (M = 15%) or following an intervention aimed at decreasing response effort combined with prompting (M = 28%). After implementing an intervention involving specified performance criterion and performance feedback, 86% of clinicians reached the established goal. Results of a component analysis suggested that the presentation of both the specified performance criterion and supporting contingencies was necessary to maintain acceptable levels of performance. PMID:24928213
MODIFIED CHOKE FLOW CRITERION FOR THE TWO-PHASE TWO-FLUID MODEL
Suneet Singh; Vincent A. Mousseau
2009-05-01
A choked condition exists when mass flow rate becomes independent of the downstream conditions. In other words, no information can propagate in the upstream direction under this condition. The real part of the solution of the characteristic equation for the model represents velocity of the signal propagation and the imaginary part is the growth (or decay) rate of that signal. Therefore, if the real part of these eigenvalues is positive then no signal propagates in the upstream direction (choosing downstream direction to be the positive direction) resulting in the choke flow. In order to develop the choke criterion, a non-dimensional form of the characteristic equation is derived for the standard two-phase two-fluid model. The equation is in the terms of a slip Mach number Ms. It can be shown that the slip Mach number is small for many applications including nuclear reactor safety simulations. The eigenvalues of the characteristic equation are obtained as a power series expansion about the point Ms = 0. These eigenvalues are used to develop a choking criterion for the compressible two-phase flows.
Criterion for stability of Goldstone modes and Fermi liquid behavior in a metal with broken symmetry
Watanabe, Haruki; Vishwanath, Ashvin
2014-01-01
There are few general physical principles that protect the low-energy excitations of a quantum phase. Of these, Goldstone’s theorem and Landau–Fermi liquid theory are the most relevant to solids. We investigate the stability of the resulting gapless excitations—Nambu–Goldstone bosons (NGBs) and Landau quasiparticles—when coupled to one another, which is of direct relevance to metals with a broken continuous symmetry. Typically, the coupling between NGBs and Landau quasiparticles vanishes at low energies, leaving the gapless modes unaffected. If, however, the low-energy coupling is nonvanishing, non-Fermi liquid behavior and overdamped bosons are expected. Here we prove a general criterion that specifies when the coupling is nonvanishing. It is satisfied by the case of a nematic Fermi fluid, consistent with earlier microscopic calculations. In addition, the criterion identifies a new kind of symmetry breaking—of magnetic translations—where nonvanishing couplings should arise, opening a previously unidentified route to realizing non-Fermi liquid phases. PMID:25349386
Chen, Yunjie; Roux, Benoît
2015-01-14
A family of hybrid simulation methods that combines the advantages of Monte Carlo (MC) with the strengths of classical molecular dynamics (MD) consists in carrying out short non-equilibrium MD (neMD) trajectories to generate new configurations that are subsequently accepted or rejected via an MC process. In the simplest case where a deterministic dynamic propagator is used to generate the neMD trajectories, the familiar Metropolis acceptance criterion based on the change in the total energy ΔE, min[1, exp( − βΔE)], guarantees that the hybrid algorithm will yield the equilibrium Boltzmann distribution. However, the functional form of the acceptance probability is more complex when the non-equilibrium switching process is generated via a non-deterministic stochastic dissipative propagator coupled to a heat bath. Here, we clarify the conditions under which the Metropolis criterion remains valid to rigorously yield a proper equilibrium Boltzmann distribution within hybrid neMD-MC algorithm.
Stellar Spectral Subclasses Classification Based on Fisher Criterion and Manifold Learning
NASA Astrophysics Data System (ADS)
Zhong-bao, Liu; Li-peng, Song
2015-08-01
Linear Discriminant Analysis (LDA) and Locality Preserving Projections (LPP) are two widely used feature extraction methods. The advantage of LDA is that it takes the global structure of the data into consideration by maximizing the ratio of the between-class scatter to the within-class scatter. LPP tries to preserve the local structure of the data. The global and local structure of the data are very important in dealing with feature extraction problems but it is regretful that the above two methods cannot fully utilize all the information. In view of this, Modified Discriminant Analysis based on Fisher Criterion and Manifold Learning (MDA) is proposed in this paper. Two important concepts are introduced: Manifold based Within-Class Scatter (MWCS) and Manifold based Between-Class Scatter (MBCS). MDA aims to find an optimal projection matrix by maximizing the ratio of MBCS to MWCS based on Fisher criterion. In this paper, we will investigate the performance of MDA in the stellar spectral subclasses classification. We first reduce the dimension of spectra data by PCA (Principal Component Analysis), LDA, LPP, and MDA, respectively. Then we apply support vector machine (SVM) to classify the four subclasses of K-type spectra, three subclasses of F-type spectra, and three subclasses of G-type spectra from Sloan Digital Sky Survey (SDSS). The comparative experiment results verify MDA can preserve both the local and global structure of the data when embed the original data into much lower dimensional space.
NASA Astrophysics Data System (ADS)
Lahaie, D. J.; Bouchard, M.
2001-08-01
The mechanical response of a semisolid body to an applied, uniaxial strain rate has been expressed as a function of strain by modifying an existing analysis based on an idealized representation of the microstructure. An existing mechanical criterion for hot tearing of the semisolid body has been adapted to the deformation mechanisms. The resulting hot tearing model shows that the strength of the body depends on the strain, the viscosity of the intergranular fluid, the solid fraction, the isothermal compressibility of the fluid, the surface tension of the liquid, the limiting liquid-film thickness for viscous flow and a parameter m, which describes microstructure. The effect of each parameter on the mechanical response and the onset of hot tearing has been examined for ranges of values relevant to aluminum alloys and the direct-chill (DC) casting process. The parameter testing has shown that the mechanical response predicted by the model agrees well with some experimental data for both the mechanisms of fracture and the parameters that govern the process. An adjustment of unknown model parameters to experimental data would permit use of the model as a constitutive law and a fracture criterion for numerical modeling of hot tearing during the solidification of Al alloys by DC casting.
Building a maintenance policy through a multi-criterion decision-making model
NASA Astrophysics Data System (ADS)
Faghihinia, Elahe; Mollaverdi, Naser
2012-08-01
A major competitive advantage of production and service systems is establishing a proper maintenance policy. Therefore, maintenance managers should make maintenance decisions that best fit their systems. Multi-criterion decision-making methods can take into account a number of aspects associated with the competitiveness factors of a system. This paper presents a multi-criterion decision-aided maintenance model with three criteria that have more influence on decision making: reliability, maintenance cost, and maintenance downtime. The Bayesian approach has been applied to confront maintenance failure data shortage. Therefore, the model seeks to make the best compromise between these three criteria and establish replacement intervals using Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE II), integrating the Bayesian approach with regard to the preference of the decision maker to the problem. Finally, using a numerical application, the model has been illustrated, and for a visual realization and an illustrative sensitivity analysis, PROMETHEE GAIA (the visual interactive module) has been used. Use of PROMETHEE II and PROMETHEE GAIA has been made with Decision Lab software. A sensitivity analysis has been made to verify the robustness of certain parameters of the model.
Robust time reversal focusing based on Maximin criterion in a waveguide with uncertain water depth
NASA Astrophysics Data System (ADS)
Pan, Xiang; Wang, Nan; Zhang, JiangFan; Xu, Wen; Gong, XianYi
2013-10-01
Time reversal processing (TRP) might be regarded as matched field processing with known environmental knowledge. However, the performance of TRP is degraded in an uncertain environment. A technique based on the Maximin criterion is proposed for enhancing the robustness of TRP in a waveguide with uncertain water depth. The relationship between the water depth and the focal spot translation is examined based on the waveguide-invariant theory. Then the time reversal transmission scheme with the Maximin criterion is performed to maximize the minimum transmission power on a target of interest. At the receiving end, coherent summation operation is carried out over the received data by a reception focusing bank. If it is necessary to enhance the target echo further, the iterative time reversal can be considered where the target echo corresponding to the first time reversal transmission is regarded as a secondary source. Numerical simulations and experimental results of the target localization in a waveguide tank have verified the effectiveness of robust TRP.
NASA Astrophysics Data System (ADS)
Lin, Yi-Kuei; Yeh, Cheng-Ta
2013-05-01
From the perspective of supply chain management, the selected carrier plays an important role in freight delivery. This article proposes a new criterion of multi-commodity reliability and optimises the carrier selection based on such a criterion for logistics networks with routes and nodes, over which multiple commodities are delivered. Carrier selection concerns the selection of exactly one carrier to deliver freight on each route. The capacity of each carrier has several available values associated with a probability distribution, since some of a carrier's capacity may be reserved for various orders. Therefore, the logistics network, given any carrier selection, is a multi-commodity multi-state logistics network. Multi-commodity reliability is defined as a probability that the logistics network can satisfy a customer's demand for various commodities, and is a performance indicator for freight delivery. To solve this problem, this study proposes an optimisation algorithm that integrates genetic algorithm, minimal paths and Recursive Sum of Disjoint Products. A practical example in which multi-sized LCD monitors are delivered from China to Germany is considered to illustrate the solution procedure.
Beltukov, Y M; Fusco, C; Parshin, D A; Tanguy, A
2016-02-01
The vibrational properties of model amorphous materials are studied by combining complete analysis of the vibration modes, dynamical structure factor, and energy diffusivity with exact diagonalization of the dynamical matrix and the kernel polynomial method, which allows a study of very large system sizes. Different materials are studied that differ only by the bending rigidity of the interactions in a Stillinger-Weber modelization used to describe amorphous silicon. The local bending rigidity can thus be used as a control parameter, to tune the sound velocity together with local bonds directionality. It is shown that for all the systems studied, the upper limit of the Boson peak corresponds to the Ioffe-Regel criterion for transverse waves, as well as to a minimum of the diffusivity. The Boson peak is followed by a diffusivity's increase supported by longitudinal phonons. The Ioffe-Regel criterion for transverse waves corresponds to a common characteristic mean-free path of 5-7 Å (which is slightly bigger for longitudinal phonons), while the fine structure of the vibrational density of states is shown to be sensitive to the local bending rigidity. PMID:26986404
Reliability and criterion-related validity of a new repeated agility test.
Fessi, M S; Makni, E; Jemni, M; Elloumi, M; Chamari, K; Nabli, M A; Padulo, J; Moalla, W
2016-06-01
The study aimed to assess the reliability and the criterion-related validity of a new repeated sprint T-test (RSTT) that includes intense multidirectional intermittent efforts. The RSTT consisted of 7 maximal repeated executions of the agility T-test with 25 s of passive recovery rest in between. Forty-five team sports players performed two RSTTs separated by 3 days to assess the reliability of best time (BT) and total time (TT) of the RSTT. The intra-class correlation coefficient analysis revealed a high relative reliability between test and retest for BT and TT (>0.90). The standard error of measurement (<0.50) showed that the RSTT has a good absolute reliability. The minimal detectable change values for BT and TT related to the RSTT were 0.09 s and 0.58 s, respectively. To check the criterion-related validity of the RSTT, players performed a repeated linear sprint (RLS) and a repeated sprint with changes of direction (RSCD). Significant correlations between the BT and TT of the RLS, RSCD and RSTT were observed (p<0.001). The RSTT is, therefore, a reliable and valid measure of the intermittent repeated sprint agility performance. As this ability is required in all team sports, it is suggested that team sports coaches, fitness coaches and sports scientists consider this test in their training follow-up. PMID:27274109
Reliability and criterion-related validity of a new repeated agility test
Makni, E; Jemni, M; Elloumi, M; Chamari, K; Nabli, MA; Padulo, J; Moalla, W
2016-01-01
The study aimed to assess the reliability and the criterion-related validity of a new repeated sprint T-test (RSTT) that includes intense multidirectional intermittent efforts. The RSTT consisted of 7 maximal repeated executions of the agility T-test with 25 s of passive recovery rest in between. Forty-five team sports players performed two RSTTs separated by 3 days to assess the reliability of best time (BT) and total time (TT) of the RSTT. The intra-class correlation coefficient analysis revealed a high relative reliability between test and retest for BT and TT (>0.90). The standard error of measurement (<0.50) showed that the RSTT has a good absolute reliability. The minimal detectable change values for BT and TT related to the RSTT were 0.09 s and 0.58 s, respectively. To check the criterion-related validity of the RSTT, players performed a repeated linear sprint (RLS) and a repeated sprint with changes of direction (RSCD). Significant correlations between the BT and TT of the RLS, RSCD and RSTT were observed (p<0.001). The RSTT is, therefore, a reliable and valid measure of the intermittent repeated sprint agility performance. As this ability is required in all team sports, it is suggested that team sports coaches, fitness coaches and sports scientists consider this test in their training follow-up. PMID:27274109
Zheng, Yuesheng; Zhang, Bo He, Jinliang
2015-06-15
The positive dc corona plasmas between coaxial cylinders in air under the application of a self-sustained criterion with photoionization are investigated in this paper. A photon absorption function suitable for cylindrical electrode, which can characterize the total photons within the ionization region, is proposed on the basis of the classic corona onset criteria. Based on the general fluid model with the self-sustained criterion, the role of photoionization in the ionization region is clarified. It is found that the surface electric field keeps constant under a relatively low corona current, while it is slightly weakened with the increase of the corona current. Similar tendencies can be found under different conductor radii and relative air densities. The small change of the surface electric field will become more significant for the electron density distribution as well as the ionization activity under a high corona current, compared with the results under the assumption of a constant surface field. The assumption that the surface electric field remains constant should be corrected with the increase of the corona current when the energetic electrons with a distance from the conductor surface are concerned.
Watanabe, Haruki; Vishwanath, Ashvin
2014-11-18
There are few general physical principles that protect the low-energy excitations of a quantum phase. Of these, Goldstone's theorem and Landau-Fermi liquid theory are the most relevant to solids. We investigate the stability of the resulting gapless excitations--Nambu-Goldstone bosons (NGBs) and Landau quasiparticles--when coupled to one another, which is of direct relevance to metals with a broken continuous symmetry. Typically, the coupling between NGBs and Landau quasiparticles vanishes at low energies, leaving the gapless modes unaffected. If, however, the low-energy coupling is nonvanishing, non-Fermi liquid behavior and overdamped bosons are expected. Here we prove a general criterion that specifies when the coupling is nonvanishing. It is satisfied by the case of a nematic Fermi fluid, consistent with earlier microscopic calculations. In addition, the criterion identifies a new kind of symmetry breaking--of magnetic translations--where nonvanishing couplings should arise, opening a previously unidentified route to realizing non-Fermi liquid phases. PMID:25349386
Kaufmann, Esther; Wittmann, Werner W.
2016-01-01
The success of bootstrapping or replacing a human judge with a model (e.g., an equation) has been demonstrated in Paul Meehl’s (1954) seminal work and bolstered by the results of several meta-analyses. To date, however, analyses considering different types of meta-analyses as well as the potential dependence of bootstrapping success on the decision domain, the level of expertise of the human judge, and the criterion for what constitutes an accurate decision have been missing from the literature. In this study, we addressed these research gaps by conducting a meta-analysis of lens model studies. We compared the results of a traditional (bare-bones) meta-analysis with findings of a meta-analysis of the success of bootstrap models corrected for various methodological artifacts. In line with previous studies, we found that bootstrapping was more successful than human judgment. Furthermore, bootstrapping was more successful in studies with an objective decision criterion than in studies with subjective or test score criteria. We did not find clear evidence that the success of bootstrapping depended on the decision domain (e.g., education or medicine) or on the judge’s level of expertise (novice or expert). Correction of methodological artifacts increased the estimated success of bootstrapping, suggesting that previous analyses without artifact correction (i.e., traditional meta-analyses) may have underestimated the value of bootstrapping models. PMID:27327085
A Research on the Adaptability of Collision Criterion1,2
NASA Astrophysics Data System (ADS)
Li, Jia-Long; Xiong, Jian-Ning; Xu, Xiao-Li; Zhao, Chang-Yin
2015-07-01
With the rising number of space debris, people pay more and more attention to the space debris collision avoidance system (SDCAS). In the early 1990s, the BOX method is commonly used as a collision criterion to decide whether the avoiding maneuver is necessary for a spacecraft. But this method has low practicability, so the method of collision probability is developed. This method takes the relative distance and other geometrical parameters at the en time of two space objects into consideration. However, the mathematical model of this collision criterion depends highly on the orbit errors, so it may lead to some inaccurate results. In this paper, the rendezvous of two orbits are sim, and the errors are considered, then the relative distance at the moment of their closest approach and the collision probability are calculated. The re indicate that the covariance of position errors plays an indispensable role in measuring the risk of collision. When the precision of orbit prediction is not very good, it is better to combine the BOX method and the collision probability method in the SDCAS.
NASA Astrophysics Data System (ADS)
Beltukov, Y. M.; Fusco, C.; Parshin, D. A.; Tanguy, A.
2016-02-01
The vibrational properties of model amorphous materials are studied by combining complete analysis of the vibration modes, dynamical structure factor, and energy diffusivity with exact diagonalization of the dynamical matrix and the kernel polynomial method, which allows a study of very large system sizes. Different materials are studied that differ only by the bending rigidity of the interactions in a Stillinger-Weber modelization used to describe amorphous silicon. The local bending rigidity can thus be used as a control parameter, to tune the sound velocity together with local bonds directionality. It is shown that for all the systems studied, the upper limit of the Boson peak corresponds to the Ioffe-Regel criterion for transverse waves, as well as to a minimum of the diffusivity. The Boson peak is followed by a diffusivity's increase supported by longitudinal phonons. The Ioffe-Regel criterion for transverse waves corresponds to a common characteristic mean-free path of 5-7 Å (which is slightly bigger for longitudinal phonons), while the fine structure of the vibrational density of states is shown to be sensitive to the local bending rigidity.
A channel-selection criterion for suppressing reverberation in cochlear implants.
Kokkinakis, Kostas; Hazrati, Oldooz; Loizou, Philipos C
2011-05-01
Little is known about the extent to which reverberation affects speech intelligibility by cochlear implant (CI) listeners. Experiment 1 assessed CI users' performance using Institute of Electrical and Electronics Engineers (IEEE) sentences corrupted with varying degrees of reverberation. Reverberation times of 0.30, 0.60, 0.80, and 1.0 s were used. Results indicated that for all subjects tested, speech intelligibility decreased exponentially with an increase in reverberation time. A decaying-exponential model provided an excellent fit to the data. Experiment 2 evaluated (offline) a speech coding strategy for reverberation suppression using a channel-selection criterion based on the signal-to-reverberant ratio (SRR) of individual frequency channels. The SRR reflects implicitly the ratio of the energies of the signal originating from the early (and direct) reflections and the signal originating from the late reflections. Channels with SRR larger than a preset threshold were selected, while channels with SRR smaller than the threshold were zeroed out. Results in a highly reverberant scenario indicated that the proposed strategy led to substantial gains (over 60 percentage points) in speech intelligibility over the subjects' daily strategy. Further analysis indicated that the proposed channel-selection criterion reduces the temporal envelope smearing effects introduced by reverberation and also diminishes the self-masking effects responsible for flattened formants. PMID:21568424
A criterion to classify asteroids and comets based on the orbital parameters
NASA Astrophysics Data System (ADS)
Tancredi, Gonzalo
2014-05-01
The classification criterion between asteroids and comets has evolved in recent decades, but the main distinction remains unchanged. Comets present gas and dust ejection from the surface at some point of their orbits, therefore, these objects are considered to be active. On the other hand, asteroids do not show any kind of large scale gas and dust ejection, they are inert. Nevertheless, this classification scheme is impractical when we have more than 500,000 asteroids already discovered. In addition, comets are not active all along their orbits. In order for a comet to display activity at present or in the recent past in the inner region of the Solar System (heliocentric distance <2 AU), the cometary orbit must be unstable in the time scale on the order of ten thousands of years; otherwise, the object should have completely consumed its volatile component. Close encounters with the most massive planets is the only mechanism that could produce “macroscopic” instabilities on a short time scale. The macroscopic changes in the orbital elements can be detected in a numerical integration of the dynamical evolution of the object over a time scale of several thousand years. This procedure to identify asteroids in cometary-like orbits is also impractical because it would require months of computing time. Therefore, a classification scheme based on the orbital elements to identify the border cases between the asteroid and comet populations is urgently required. We present a criterion to classify asteroids and comets and to find the border case based on the Tisserand’s parameter, the Minimum Orbital Intersection Distance (MOID), and considering some information regarding the aphelion and perihelion distances. Objects in mean-motion are disregarded. After applying a filter to the sample of over half a million asteroids already discovered to select the precise orbits and to the sample of 487 short-period comets, we apply the proposed classification criterion. The
Pfaffel, Andreas; Kollmayer, Marlene; Schober, Barbara; Spiel, Christiane
2016-01-01
A recurring methodological problem in the evaluation of the predictive validity of selection methods is that the values of the criterion variable are available for selected applicants only. This so-called range restriction problem causes biased population estimates. Correction methods for direct and indirect range restriction scenarios have widely studied for continuous criterion variables but not for dichotomous ones. The few existing approaches are inapplicable because they do not consider the unknown base rate of success. Hence, there is a lack of scientific research on suitable correction methods and the systematic analysis of their accuracies in the cases of a naturally or artificially dichotomous criterion. We aim to overcome this deficiency by viewing the range restriction problem as a missing data mechanism. We used multiple imputation by chained equations to generate complete criterion data before estimating the predictive validity and the base rate of success. Monte Carlo simulations were conducted to investigate the accuracy of the proposed correction in dependence of selection ratio, predictive validity, and base rate of success in an experimental design. In addition, we compared our proposed missing data approach with Thorndike’s well-known correction formulas that have only been used in the case of continuous criterion variables so far. The results show that the missing data approach is more accurate in estimating the predictive validity than Thorndike’s correction formulas. The accuracy of our proposed correction increases as the selection ratio and the correlation between predictor and criterion increase. Furthermore, the missing data approach provides a valid estimate of the unknown base rate of success. On the basis of our findings, we argue for the use of multiple imputation by chained equations in the evaluation of the predictive validity of selection methods when the criterion is dichotomous. PMID:27019277
Examination of a Rock Failure Criterion Based on Circumferential Tensile Strain
NASA Astrophysics Data System (ADS)
Fujii, , Y.; Kiyama, , T.; Ishijima, Y.; Kodama, J.
Uniaxial compression, triaxial compression and Brazialian tests were conducted on several kinds of rock, with particular attention directed to the principal tensile strain. In this paper we aim to clarify the effects of the experimental environment-such as confining pressure, loading rate, water content and anisotropy-on the critical tensile strain, i.e., the measured principal tensile strain at peak load.It was determined that the chain-type extensometer is a most suitable method for measuring the critical tensile strain in uniaxial compression tests. It is also shown that the paper-based strain gage, whose effective length is less than or equal to a tenth of the specimen's diameter and glued on with a rubber-type adhesive, can be effectively used in the Brazilian tests.The effect of confining pressure PC on the critical tensile strain ɛTC in the brittle failure region was between -0.02 × 10-10 Pa-1 and 0.77 × 10-10 Pa-1. This pressure sensitivity is small compared to the critical tensile strain values of around -0.5 × 10-2. The strain rate sensitivities ∂ɛTC/∂{log(d|ɛ|/dt)} were observed in the same way as the strength constants in other failure criteria. They were found to be from -0.10 × 10-3 to -0.52 × 10-3 per order of magnitude in strain rate in the triaxial tests. The average magnitude of the critical tensile strain ɛTC increased due to the presence of water by 4% to 20% for some rocks, and decreased by 22% for sandstone. It can at least be said that the critical tensile strain is less sensitive to water content than the uniaxial compressive strength under the experimental conditions reported here. An obvious anisotropy was observed in the P-wave velocity and in the uniaxial compressive strength of Pombetsu sandstone. It was not observed, however, in the critical tensile strain, although the data do show some variation.A "tensile strain criterion" was proposed, based on the above experimental results. This criterion signifies that stress begins
Ignition criterion for heterogeneous energetic materials based on hotspot size-temperature threshold
NASA Astrophysics Data System (ADS)
Barua, A.; Kim, S.; Horie, Y.; Zhou, M.
2013-02-01
A criterion for the ignition of granular explosives (GXs) and polymer-bonded explosives (PBXs) under shock and non-shock loading is developed. The formulation is based on integration of a quantification of the distributions of the sizes and locations of hotspots in loading events using a cohesive finite element method (CFEM) developed recently and the characterization by Tarver et al. [C. M. Tarver et al., "Critical conditions for impact- and shock-induced hot spots in solid explosives," J. Phys. Chem. 100, 5794-5799 (1996)] of the critical size-temperature threshold of hotspots required for chemical ignition of solid explosives. The criterion, along with the CFEM capability to quantify the thermal-mechanical behavior of GXs and PBXs, allows the critical impact velocity for ignition, time to ignition, and critical input energy at ignition to be determined as functions of material composition, microstructure, and loading conditions. The applicability of the relation between the critical input energy (E) and impact velocity of James [H. R. James, "An extension to the critical energy criterion used to predict shock initiation thresholds," Propellants, Explos., Pyrotech. 21, 8-13 (1996)] for shock loading is examined, leading to a modified interpretation, which is sensitive to microstructure and loading condition. As an application, numerical studies are undertaken to evaluate the ignition threshold of granular high melting point eXplosive, octahydro-1,3,5,7-tetranitro-1,2,3,5-tetrazocine (HMX) and HMX/Estane PBX under loading with impact velocities up to 350 ms-1 and strain rates up to 105 s-1. Results show that, for the GX, the time to criticality (tc) is strongly influenced by initial porosity, but is insensitive to grain size. Analyses also lead to a quantification of the differences between the responses of the GXs and PBXs in terms of critical impact velocity for ignition, time to ignition, and critical input energy at ignition. Since the framework permits
Geoscience Education and Public Outreach AND CRITERION 2: MAKING A BROADER IMPACT
NASA Astrophysics Data System (ADS)
Marlino, M.; Scotchmoor, J. G.
2005-12-01
The geosciences influence our daily lives and yet often go unnoticed by the general public. From the moment we listen to the weather report and fill-up our cars for the daily commute, until we return to our homes constructed from natural resources, we rely on years of scientific research. The challenge facing the geosciences is to make explicit to the public not only the criticality of the research whose benefits they enjoy, but also to actively engage them as partners in the research effort, by providing them with sufficient understanding of the scientific enterprise so that they become thoughtful and proactive when making decisions in the polling booth. Today, there is broad recognition within the science and policy community that communication needs to be more effective, more visible, and that the public communication of the scientific enterprise is critical not only to its taxpayer support, but also to maintenance of a skilled workforce and the standard of living expected by many Americans. In 1997, the National Science Board took the first critical step in creating a cultural change in the scientific community by requiring explicit consideration of the broader impacts of research in every research proposal. The so-called Criterion 2 has catalyzed a dramatic shift in expectations within the geoscience community and an incentive for finding ways to encourage the science research community to select education and public outreach as a venue for responding to Criterion 2. In response, a workshop organized by the University of California Museum of Paleontology and the Digital Library for Earth System Education (DLESE) was held on the Berkeley campus May 11-13, 2005. The Geoscience EPO Workshop purposefully narrowed its focus to that of education and public outreach. This workshop was based on the premise that there are proven models and best practices for effective outreach strategies that need to be identified and shared with research scientists. Workshop
Assessment of the pubic force as a pelvic injury criterion in side impact.
Leport, Tiphaine; Baudrit, Pascal; Trosseille, Xavier; Petit, Philippe; Palisson, Anna; Vallancien, Guy
2007-10-01
In the literature, injuries at the ischio or ilio pubic ramus level are reported to occur to approximately (3/4) of the occupants injured at the pelvis during side impact. Assuming that the load going through the pubis was a good indicator of the ramus stress, the pubic force was widely accepted as a protection criterion for pelvic fractures on side impact dummies. However, no data regarding the actual loads going through the pubis is currently available in the literature for Post Mortem Human Subjects (PMHS) in dynamic conditions. The goal of this study was to determine pelvic biofidelity specifications in terms of load path, to evaluate the pertinence of the pubic force as a criterion, and to develop a pelvic injury risk curve as a function of the pubic force. For that purpose, a pubic load cell was developed for PMHS use, and 16 side impact tests were performed on 8 PMHS using boundary conditions similar to impactor tests and sled tests reported in the literature. One kind of impact was applied on one side of a subject and the other kind of impact was then applied on the other side of the same subject, at non injury severities. The ratio between the peak external force and the peak pubic force was calculated for each subject, and a mean ratio was then calculated for each of the test conditions. These ratios were finally used to calculate the pubic forces from the external pelvic forces for 90 PMHS side impact test data available in the literature. Injury risk curves as a function of the pubic force were developed from these data. Two normalized pubic force corridors from the 16 tests are presented, the first one for the impactor tests, the second one for the sled-like tests. The test results show statistically different ratios between the peak external force and the peak pubic force, for the two configurations (an average ratio of 3.3 for impactor tests and 4.6 for sled-like tests). The PMHS injury risk curves based on the external pelvic force were observed to
Mayorga-Vega, Daniel; Aguilar-Soto, Pablo; Viciana, Jesús
2015-01-01
The main purpose of the present meta-analysis was to examine the criterion-related validity of the 20-m shuttle run test for estimating cardiorespiratory fitness. Relevant studies were searched from twelve electronic databases up to December 2014, as well as from several alternative modes of searching. The Hunter-Schmidt’s psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the 20-m shuttle run test. From 57 studies that were included in the present meta-analysis, a total of 78 correlation values were analyzed. The overall results showed that the performance score of the 20-m shuttle run test had a moderate-to-high criterion-related validity for estimating maximum oxygen uptake (rp = 0.66-0.84), being higher when other variables (e.g. sex, age or body mass) were used (rp = 0.78-0.95). The present meta-analysis also showed that the criterion-related validity of Léger’s protocol was statistically higher for adults (rp = 0.94, 0.87-1.00) than for children (rp = 0.78, 0.72-0.85). However, sex and maximum oxygen uptake level do not seem to affect the criterion-related validity values. When an individual’s maximum oxygen uptake attained during a laboratory-based test is not feasible, the 20-m shuttle run test seems to be a useful alternative for estimating cardiorespiratory fitness. In adults the performance score only seems to be a strong estimator of cardiorespiratory fitness, in contrast among children the performance score should be combined with other variables. Nevertheless, as in the application of any physical fitness field test, evaluators must be aware that the performance score of the 20-m shuttle run test is simply an estimation and not a direct measure of cardiorespiratory fitness. Key points Overall the 20-m shuttle run test has a moderate-to-high mean criterion-related validity for estimating cardiorespiratory fitness. The criterion-related validity of the 20-m shuttle run test is significantly
The early stop heuristic: A new convergence criterion for K-means
NASA Astrophysics Data System (ADS)
Mexicano, A.; Rodríguez, R.; Cervantes, S.; Montes, P.; Jiménez, M.; Almanza, N.; Abrego, A.
2016-06-01
In this paper, an enhanced version of the K-Means algorithm that incorporates a new convergence criterion is presented. The largest centroid displacement at each iteration was used as mean to define whether the algorithm stops or not its execution. Computational experiments showed that in general, the Early Stop Heuristic is able to reduce the execution time of the standard version without a significant quality reduction. According to the experimentation, the Early Stop Heuristic reached a time reduction up to 87.06% only a quality reduction of 2.46% for the Transactions dataset, the worst case occurred when the Skin instance was grouped into 200 clusters obtaining a 79.04% in reduction time, and a 4.27% in quality reduction.
Stellar evolution at high mass with semiconvective mixing according to the Ledoux criterion
NASA Technical Reports Server (NTRS)
Stothers, R.; Chin, C.-W.
1975-01-01
The effects of semiconvective mixing are investigated in evolutionary sequences of models for stars of 10, 15, and 30 solar masses with four different initial chemical compositions. The models are constructed using the Ledoux criterion for both the definition of convective instability and the state of convective neutrality assumed to be attained in regions with a gradient of mean molecular weight. It is shown that semiconvection is nonexistent at 10 solar masses, of minor importance at 15 solar masses, but covers most of the intermediate zone at 30 solar masses, developing into full convection if the initial hydrogen and metals abundances are high. The effects of low initial hydrogen and metals abundances are examined, and the critical importance is demonstrated of the depths of the semiconvective zone and the outer convective envelope in promoting a blue loop and determining the maximum effective temperature on the loop. The extent of the thermally stable stages of the blue-loop phase is determined.
Ramirez-Romero, P. |; Oris, J.T.
1995-12-31
The goal of this study was to evaluate the fluoranthene sediment quality criterion (SQC) for the protection of benthic organisms in the presence of ultraviolet (UV) radiation. The authors exposed the benthic amphipod Hyalella azteca to clean and fluoranthene-spiked sediments at the SQC concentration (620 {micro}g/goc) in the presence or absence of UV radiation. When UV radiation was used the test-organisms showed signs of stress (slow response to physical disturbance) after 48 hrs. When comparing the data of adults vs. juveniles, the authors found that the adults were more sensitive. After 5 days of exposure 90% of the adults were dead vs. 62% of the juveniles. This could have been the result of greater exposure to UV radiation caused by a larger body surface area on the adults. Studies of the combined effects of fluoranthene contaminated sediments and UV radiation using benthic organisms indicate that the current fluoranthene SOC requires further examination.
Baalrud, S. D.; Hegna, C. C.; Callen, J. D.
2009-11-13
A generalized Lenard-Balescu theory that accounts for instability-enhanced collective responses is used to calculate the collisional friction between ion species in the plasma-boundary transition region (presheath). Ion-ion streaming instabilities are shown to cause such a strong frictional force that the relative flow speed between ion species cannot significantly exceed the critical threshold value (DELTAV{sub c}) at which instability onset occurs. When combined with the Bohm criterion, this condition uniquely determines the flow speed of each ion species at the plasma-sheath boundary. For cold ions, DELTAV{sub c}->0 and each ion species leaves the plasma at a common system sound speed c{sub s}.
Baalrud, S D; Hegna, C C; Callen, J D
2009-11-13
A generalized Lenard-Balescu theory that accounts for instability-enhanced collective responses is used to calculate the collisional friction between ion species in the plasma-boundary transition region (presheath). Ion-ion streaming instabilities are shown to cause such a strong frictional force that the relative flow speed between ion species cannot significantly exceed the critical threshold value (DeltaV(c)) at which instability onset occurs. When combined with the Bohm criterion, this condition uniquely determines the flow speed of each ion species at the plasma-sheath boundary. For cold ions, DeltaV(c) --> 0 and each ion species leaves the plasma at a common system sound speed c(s). PMID:20365986
A boundary-coupled generalization of the Newcomb stability criterion. [for bounded magnetized plasma
NASA Technical Reports Server (NTRS)
Ray, A.; Van Hoven, G.
1982-01-01
In magnetohydrodynamic problems in which there are boundaries in the axial or azimuthal symmetry directions, the energy principle involves multiple nonorthogonal trial perturbations. The subsequent Euler-Lagrange coupling of these allowed excitations necessitates a generalization of the Newcomb necessary-and-sufficient stability criterion. This extension, in which the absence of a conjugate point (instead of a simple zero) provides stability, is described in this paper. An important aspect of the proof involves the treatment of certain asymmetries which arise in the presence of the anisotropy caused by the magnetic field. The general method described here has applications to finite-length axial laboratory pinches and to astrophysical plasmas with rooted magnetic fields.
Direct method for second-order sensitivity analysis of modal assurance criterion
NASA Astrophysics Data System (ADS)
Lei, Sheng; Mao, Kuanmin; Li, Li; Xiao, Weiwei; Li, Bin
2016-08-01
A Lagrange direct method is proposed to calculate the second-order sensitivity of modal assurance criterion (MAC) values of undamped systems. The eigenvalue problem and normalizations of eigenvectors, which augmented by using some Lagrange multipliers, are used as the constraints of the Lagrange functional. Once the Lagrange multipliers are determined, the sensitivities of MAC values can be evaluated directly. The Lagrange direct method is accurate, efficient and easy to implement. A simply supported beam is utilized to check the accuracy of the proposed method. A frame is adopted to validate the predicting capacity of the first- and second-order sensitivities of MAC values. It is shown that the computational costs of the proposed method can be remarkably reduced in comparison with those of the indirect method without loss of accuracy.
NASA Technical Reports Server (NTRS)
Crowe, D. R.; Henricks, W.
1983-01-01
The combined load statistics are developed by taking the acoustically induced load to be a random population, assumed to be stationary. Each element of this ensemble of acoustically induced loads is assumed to have the same power spectral density (PSD), obtained previously from a random response analysis employing the given acoustic field in the STS cargo bay as a stationary random excitation. The mechanically induced load is treated as either (1) a known deterministic transient, or (2) a nonstationary random variable of known first and second statistical moments which vary with time. A method is then shown for determining the probability that the combined load would, at any time, have a value equal to or less than a certain level. Having obtained a statistical representation of how the acoustic and mechanical loads are expected to combine, an analytical approximation for defining design levels for these loads is presented using the First Passage failure criterion.
A unified optical damage criterion based on the probability density distribution of detector signals
NASA Astrophysics Data System (ADS)
Somoskoi, T.; Vass, Cs.; Mero, M.; Mingesz, R.; Bozoki, Z.; Osvay, K.
2013-11-01
Various methods and procedures have been developed so far to test laser induced optical damage. The question naturally arises, that what are the respective sensitivities of these diverse methods. To make a suitable comparison, both the processing of the measured primary signal has to be at least similar to the various methods, and one needs to establish a proper damage criterion, which has to be universally applicable for every method. We defined damage criteria based on the probability density distribution of the obtained detector signals. This was determined by the kernel density estimation procedure. We have tested the entire evaluation procedure in four well-known detection techniques: direct observation of the sample by optical microscopy; monitoring of the change in the light scattering power of the target surface and the detection of the generated photoacoustic waves both in the bulk of the sample and in the surrounding air.
PID controller auto-tuning based on process step response and damping optimum criterion.
Pavković, Danijel; Polak, Siniša; Zorc, Davor
2014-01-01
This paper presents a novel method of PID controller tuning suitable for higher-order aperiodic processes and aimed at step response-based auto-tuning applications. The PID controller tuning is based on the identification of so-called n-th order lag (PTn) process model and application of damping optimum criterion, thus facilitating straightforward algebraic rules for the adjustment of both the closed-loop response speed and damping. The PTn model identification is based on the process step response, wherein the PTn model parameters are evaluated in a novel manner from the process step response equivalent dead-time and lag time constant. The effectiveness of the proposed PTn model parameter estimation procedure and the related damping optimum-based PID controller auto-tuning have been verified by means of extensive computer simulations. PMID:24035643
NASA Technical Reports Server (NTRS)
Boller, B. R.; Stolov, H. L.
1973-01-01
Explorer 18 magnetometer and plasma probe data are used to calculate the magnitude of the Kelvin-Helmholtz instability criterion for 42 crossings of the magnetopause. The 30 crossings through the dipole field region show that for low levels of geomagnetic disturbance ( Kp less than or equal to 2) large regions of the magnetopause near the nose are stable, whereas for higher levels of geomagnetic disturbance (Kp greater than 2) only a small region near the nose is stable. The unstable regions are found further downstream. Similarly, the 12 crossings through the tail show that the unstable regions are downstream of the stable regions. The Kelvin-Helmholtz mechanism might be the 'viscous interaction' discussed by Axford and Hines (1961) and the relevant parameter for worldwide geomagnetic disturbance, just as the southward interplanetary field has been firmly established as the major relevant parameter in the case of substorm activity.
Modeling a failure criterion for U-Mo/Al dispersion fuel
NASA Astrophysics Data System (ADS)
Oh, Jae-Yong; Kim, Yeon Soo; Tahk, Young-Wook; Kim, Hyun-Jung; Kong, Eui-Hyun; Yim, Jeong-Sik
2016-05-01
The breakaway swelling in U-Mo/Al dispersion fuel is known to be caused by large pore formation enhanced by interaction layer (IL) growth between fuel particles and Al matrix. In this study, a critical IL thickness was defined as a criterion for the formation of a large pore in U-Mo/Al dispersion fuel. Specifically, the critical IL thickness is given when two neighboring fuel particles come into contact with each other in the developed IL. The model was verified using the irradiation data from the RERTR tests and KOMO-4 test. The model application to full-sized sample irradiations such as IRISs, FUTURE, E-FUTURE, and AFIP-1 tests resulted in conservative predictions. The parametric study revealed that the fuel particle size and the homogeneity of the fuel particle distribution are influential for fuel performance.
Revision, Criterion Validity, and Multi-group Assessment of the Reactions to Homosexuality Scale
Smolenski, Derek J.; Diamond, Pamela M.; Ross, Michael W.; Simon Rosser, B. R.
2010-01-01
Internalized homonegativity encompasses negative attitudes toward one’s own sexual orientation, and is associated with negative mental and physical health outcomes. The Reactions to Homosexuality scale (Ross & Rosser, 1996), an instrument used to measure internalized homonegativity, has been criticized for including content irrelevant to the construct of internalized homonegativity. We revised the scale using exploratory and confirmatory factor analyses, and identified a seven-item, three-factor reduced version that demonstrated measurement invariance across racial/ethnic categorizations and between English and Spanish versions. We also investigated criterion validity by estimating correlations with hypothesized outcomes associated with outness, relationship status, sexual orientation, and gay community affiliation. The evidence of measurement invariance suggests that this scale is appropriate for pluralistic treatment or study groups. PMID:20954058
Singularity and Bohm criterion in hot positive ion species in the electronegative ion sources
NASA Astrophysics Data System (ADS)
Aslaninejad, Morteza; Yasserian, Kiomars
2016-05-01
The structure of the discharge for a magnetized electronegative ion source with two species of positive ions is investigated. The thermal motion of hot positive ions and the singularities involved with it are taken into account. By analytical solution of the neutral region, the location of the singular point and also the values of the plasma parameter such as electric potential and ion density at the singular point are obtained. A generalized Bohm criterion is recovered and discussed. In addition, for the non-neutral solution, the numerical method is used. In contrast with cold ion plasma, qualitative changes are observed. The parameter space region within which oscillations in the density and potential can be observed has been scanned and discussed. The space charge behavior in the vicinity of edge of the ion sources has also been discussed in detail.
A fracture criterion for widespread cracking in thin-sheet aluminum alloys
NASA Technical Reports Server (NTRS)
Newman, J. C., Jr.; Dawicke, D. S.; Sutton, M. A.; Bigelow, C. A.
1993-01-01
An elastic-plastic finite-element analysis was used with a critical crack-tip-opening angle (CTOA) fracture criterion to model stable crack growth in thin-sheet 2024-T3 aluminum alloy panels with single and multiple-site damage (MSD) cracks. Comparisons were made between critical angles determined from the analyses and those measured with photographic methods. Calculated load against crack extension and load against crack-tip displacement on single crack specimens agreed well with test data even for large-scale plastic deformations. The analyses were also able to predict the stable tearing behavior of large lead cracks in the presence of stably tearing MSD cracks. Small MSD cracks significantly reduced the residual strength for large lead cracks.
Si, Weijian; Qu, Xinggen; Liu, Lutao
2014-01-01
A novel direction of arrival (DOA) estimation method in compressed sensing (CS) is presented, in which DOA estimation is considered as the joint sparse recovery from multiple measurement vectors (MMV). The proposed method is obtained by minimizing the modified-based covariance matching criterion, which is acquired by adding penalties according to the regularization method. This minimization problem is shown to be a semidefinite program (SDP) and transformed into a constrained quadratic programming problem for reducing computational complexity which can be solved by the augmented Lagrange method. The proposed method can significantly improve the performance especially in the scenarios with low signal to noise ratio (SNR), small number of snapshots, and closely spaced correlated sources. In addition, the Cramér-Rao bound (CRB) of the proposed method is developed and the performance guarantee is given according to a version of the restricted isometry property (RIP). The effectiveness and satisfactory performance of the proposed method are illustrated by simulation results. PMID:24678272
A blowup criterion for viscous, compressible, and heat-conductive magnetohydrodynamic flows
NASA Astrophysics Data System (ADS)
Du, Lili; Wang, Yongfu
2015-09-01
In this paper, we proved a blowup criterion for the two-dimensional (2D) viscous, compressible, and heat-conducting magnetohydrodynamic (MHD) flows for Cauchy problem, which depends only on the divergence of the velocity vector field, as well as for the case of bounded domain with Dirichlet boundary conditions. This result indicates that the nature of the blowup for compressible models of viscous media in 2D space is similar to the barotropic compressible Navier-Stokes equations and does not depend on further sophistication of the MHD model. More precisely, taking into account the magnetic effects and heat conductivity does not introduce any new features in the blowup mechanism of full MHD flows, especially, which is independent of the temperature and the magnetic field. The results also imply the global regularity of the strong solution to compressible MHD flows, provided that velocity divergence remains bounded.
NASA Technical Reports Server (NTRS)
Yan, Tsun-Yee
1992-01-01
This paper describes an extended-source spatial acquisition process based on the maximum likelihood criterion for interplanetary optical communications. The objective is to use the sun-lit Earth image as a receiver beacon and point the transmitter laser to the Earth-based receiver to establish a communication path. The process assumes the existence of a reference image. The uncertainties between the reference image and the received image are modeled as additive white Gaussian disturbances. It has been shown that the optimal spatial acquisition requires solving two nonlinear equations to estimate the coordinates of the transceiver from the received camera image in the transformed domain. The optimal solution can be obtained iteratively by solving two linear equations. Numerical results using a sample sun-lit Earth as a reference image demonstrate that sub-pixel resolutions can be achieved in a high disturbance environment. Spatial resolution is quantified by Cramer-Rao lower bounds.
New Right Bundle Branch Block as a Criterion for Emergent Coronary Angiography
Pozen, Jonah M.; Mankad, Anit K.; Owens, John T.; Jovin, Ion S.
2015-01-01
Context: ST-segment elevations in two or more contiguous leads or new left bundle branch block (LBBB) on electrocardiography (ECG) in a patient with acute onset chest pain are diagnostic criteria for acute myocardial infarction (AMI) and generally warrant urgent coronary angiography and cardiac catheterization. However, the significance of new right bundle branch block (RBBB) without other acute ECG changes is unclear and is currently not considered a criterion. Case Report: We present a patient with chest pain, positive biomarkers of myocardial necrosis and isolated new right bundle block on ECG. He was diagnosed with AMI but did not undergo urgent reperfusion therapy in the absence of ST-segment elevations or new LBBB. However, angiography ultimately demonstrated complete coronary occlusion. Conclusion: The established criteria for emergent catheterization may prove to be more sensitive with the inclusion of the presence of new RBBB on ECG. PMID:26942134
A variational dynamic programming approach to robot-path planning with a distance-safety criterion
NASA Technical Reports Server (NTRS)
Suh, Suk-Hwan; Shin, Kang G.
1988-01-01
An approach to robot-path planning is developed by considering both the traveling distance and the safety of the robot. A computationally-efficient algorithm is developed to find a near-optimal path with a weighted distance-safety criterion by using a variational calculus and dynamic programming (VCDP) method. The algorithm is readily applicable to any factory environment by representing the free workspace as channels. A method for deriving these channels is also proposed. Although it is developed mainly for two-dimensional problems, this method can be easily extended to a class of three-dimensional problems. Numerical examples are presented to demonstrate the utility and power of this method.
NASA Astrophysics Data System (ADS)
Niwa, M.; Alves, N. C.; Caetano, A. O.; Andrade, N. S. O.
2012-01-01
The recent advent of the commercial launch and re- entry activities, for promoting the expansion of human access to space for tourism and hypersonic travel, in the already complex ambience of the global space activities, brought additional difficulties over the development of a harmonized framework of international safety rules. In the present work, with the purpose of providing some complementary elements for global safety rule development, the certification-related activities conducted in the Brazilian space program are depicted and discussed, focusing mainly on the criterion for certification basis compilation. The results suggest that the composition of a certification basis with the preferential use of internationally-recognized standards, as is the case of ISO standards, can be a first step toward the development of an international safety regulation for commercial space activities.
NASA Technical Reports Server (NTRS)
Levy, R.; Chai, K.
1978-01-01
A description is presented of an effective optimality criterion computer design approach for member size selection to improve frequency characteristics for moderately large structure models. It is shown that the implementation of the simultaneous iteration method within a natural frequency structural design optimization provides a method which is more efficient in isolating the lowest natural frequency modes than the frequently applied Stodola method. Additional computational advantages are derived by using previously converged eigenvectors at the start of the iterations during the second and the following design cycles. Vectors with random components can be used at the first design cycle, which, in relation to the entire computer time for the design program, results in only a moderate computational penalty.
Noise and sleep - A literature review and a proposed criterion for assessing effect
NASA Technical Reports Server (NTRS)
Lukas, J. S.
1975-01-01
Results of a number of studies on the effects of various types of noise on the sleep of subjects of both sexes and a wide range of age groups are reviewed to develop a tentative criterion for assessing these effects. Available data suggest that reasonably accurate predictions of sleep disruption may be made if the interfering noise is specified in units (EPNdB or EdBA) which account for its spectral characteristics and duration. When EPNdB units are used as the measure of noise intensity, the correlation coefficient between intensity and the probability of no sleep disturbance is -0.86. Because of the paucity of data on the long-term results of frequent behavioral wakings or arousals, it is suggested that disturbance of sleep be defined as an electroencephalographic change of one or more sleep stages.
Si, Weijian; Qu, Xinggen; Liu, Lutao
2014-01-01
A novel direction of arrival (DOA) estimation method in compressed sensing (CS) is presented, in which DOA estimation is considered as the joint sparse recovery from multiple measurement vectors (MMV). The proposed method is obtained by minimizing the modified-based covariance matching criterion, which is acquired by adding penalties according to the regularization method. This minimization problem is shown to be a semidefinite program (SDP) and transformed into a constrained quadratic programming problem for reducing computational complexity which can be solved by the augmented Lagrange method. The proposed method can significantly improve the performance especially in the scenarios with low signal to noise ratio (SNR), small number of snapshots, and closely spaced correlated sources. In addition, the Cramér-Rao bound (CRB) of the proposed method is developed and the performance guarantee is given according to a version of the restricted isometry property (RIP). The effectiveness and satisfactory performance of the proposed method are illustrated by simulation results. PMID:24678272
Developing criterion-based competencies for tele-intensive care unit.
Schleifer, Sarah Joy; Carroll, Karen; Moseley, Marthe J
2014-01-01
Over the last 5 years, telemedicine has developed nursing roles that differ from traditional bedside care. In the midst of this transition, current competency development models focused on task completion may not be the most effective form of proficiency validation. The procedure of competency creation for the role of tele-intensive care unit registered nurse requires a thoughtful process using stakeholders from institutional leadership to frontline staff. The process must include stakeholder approval to ensure appropriate buy-in and follow-through on the agreed-upon criteria. This can be achieved using a standardized method of concept stimulation related to the behaviors, not a memorized list of tasks, expected of a telemedicine registered nurse. This process serves as the foundation for the development of criterion-based competency statements that then allows for clearer expectations. Continually reviewing the written competencies, ensuring current applicability, and revising as needed are necessities for maintaining competence and, therefore, patient safety. PMID:24704734
A strict response criterion yields a mirror effect in the novelty paradigm.
Aberg, Carola S; Nilsson, Lars-Göran
2003-12-01
According to the novelty/encoding hypothesis (NEH; Tulving & Kroll, 1995), efficacy of encoding information into long-term memory depends on the movelty of the information. Recognition accuracy is higher for novel than for previously familiarized material. This novelty effect is not a mirror effect: the superiority of novel over familiar items is not found in the hit rates but only in the false-alarm rates. The main result in the present replication study was that novel hit rates were higher than familiar ones when the most confident responses were examined separately, and thus a mirror effect could be demonstrated for these data, for both the low- and the high-frequency words. Similarly, the word-frequency effect on hits was stronger when a stricter response criterion was applied. It was concluded that the novelty effect and the word-frequency effect are more similar to one another than has hitherto been thought. PMID:15030108
Analytical criterion for shock ignition of fusion reaction in hot spot
NASA Astrophysics Data System (ADS)
Ribeyre, X.; Tikhonchuk, V. T.; Breil, J.; Lafon, M.; Vallet, A.; Le Bel, E.
2013-11-01
Shock ignition of DT capsules involves two major steps. First, the fuel is assembled by means of a low velocity conventional implosion. At stagnation, the central core has a temperature lower than the one needed for ignition. Then a second, strong spherical converging shock, launched from a high intensity laser spike, arrives to the core. This shock crosses the core, rebounds at the target center and increases the central pressure to the ignition conditions. In this work we consider this latter phase by using the Guderley self-similar solution for converging flows. Our model accounts for the fusion reaction energy deposition, thermal and radiation losses thus describing the basic physics of hot spot ignition. The ignition criterion derived from the analytical model is successfully compared with full scale hydrodynamic simulations.
Whole-Body Reaching Movements Formulated by Minimum Muscle-Tension Change Criterion.
Kudo, Naoki; Choi, Kyuheong; Kagawa, Takahiro; Uno, Yoji
2016-05-01
It is well known that planar reaching movements of the human shoulder and elbow joints have invariant features: roughly straight hand paths and bell-shaped velocity profiles. The optimal control models with the criteria of smoothness or precision, which determine a unique movement pattern, predict such features of hand trajectories. In this letter on expanding the research on simple arm reaching movements, we examine whether the smoothness criteria can be applied to whole-body reaching movements with many degrees of freedom. Determining a suitable joint trajectory in the whole-body reaching movement corresponds to the optimization problem with constraints, since body balance must be maintained during a motion task. First, we measured human joint trajectories and ground reaction forces during whole-body reaching movements, and confirmed that subjects formed similar movements with common characteristics in the trajectories of the hand position and body center of mass. Second, we calculated the optimal trajectories according to the criteria of torque and muscle-tension smoothness. While the minimum torque change trajectories were not consistent with the experimental data, the minimum muscle-tension change model was able to predict the stereotyped features of the measured trajectories. To explore the dominant effects of the extension from the torque change to the muscle-tension change, we introduced a weighted torque change cost function. Considering the maximum voluntary contraction (MVC) force of the muscle as the weighting factor of each joint torque, we formulated the weighted torque change cost as a simplified version of the minimum muscle-tension change cost. The trajectories owing to the minimum weighted torque change criterion also showed qualitative agreement with the common features of the measured data. Proper estimation of the MVC forces in the body joints is essential to reproduce human whole-body movements according to the minimum muscle-tension change
Dlusskaia, I G; Zhdan'ko, I M; Bogdanov, Iu V
2002-01-01
Adrenoreactivity parameter (beta-ARM, one of the characteristics of individual sympathoadrenal system (SAS), can enhance the system of professional psycho-logical screening (PPS). The parameter is determined with a new technique of quantifying changes in osmoresistance of erythrocytes in the presence of adrenoblocker. The normal beta-ARM range lies within 2.0-20.0 conditional units with a rise up to 60 cond. units in consequence of regular increases in the SAS activity. To accept or reject beta-ARM as a PPS criterion, data of a series of three investigations were analyzed in attempt to correlate individual psychophysiological characteristics, operator's efficiency, cardiovascular reactions, and beta-ARM. In the first investigation, 30 male volunteers imitated operator's duties which included two-dimensional compensatory tracking with simultaneous choice between two alternatives on a training simulator. In the second investigation, 39 first-year students of a flight school were tested with the use of an automated psychological assessment system at the end of the first semester. In the third investigation, four navigators and 3 qualified test-pilots performed two-compensatory tracking using standard hand controls following exposure to radial aerobatic g-loads in and w/o anti-g suits. It was found that beta-ARM within the range of 10-20 cond. units is a criterion of good job efficiency. beta-ARM below 10 cond. units attests high adrenoreactivity only in stable conditions of work and with good skill in a particular operation. In contingency high reactivity to catecholamines may lead to loss of concentration, deterioration of temporary memory and job efficiency. beta-ARM above 20 cond. units may be determined at high operator's performance; however, during screening the risk of stress-related diseases should be taken into consideration, too. PMID:12572117
NASA Astrophysics Data System (ADS)
Chen, Ping-Feng; Krim, Hamid
2008-02-01
In this paper, we propose using two methods to determine the canonical views of 3D objects: minimum description length (MDL) criterion and compressive sensing method. MDL criterion searches for the description length that achieves the balance between model accuracy and parsimony. It takes the form of the sum of a likelihood and a penalizing term, where the likelihood is in favor of model accuracy such that more views assists the description of an object, while the second term penalizes lengthy description to prevent overfitting of the model. In order to devise the likelihood term, we propose a model to represent a 3D object as the weighted sum of multiple range images, which is used in the second method to determine the canonical views as well. In compressive sensing method, an intelligent way of parsimoniously sampling an object is presented. We make direct inference from Donoho1 and Candes'2 work, and adapt it to our model. Each range image is viewed as a projection, or a sample, of a 3D model, and by using compressive sensing theory, we are able to reconstruct the object with an overwhelming probability by scarcely sensing the object in a random manner. Compressive sensing is different from traditional compressing method in the sense that the former compress things in the sampling stage while the later collects a large number of samples and then compressing mechanism is carried out thereafter. Compressive sensing scheme is particularly useful when the number of sensors are limited or the sampling machinery cost much resource or time.
A measurable Lawson criterion and hydro-equivalent curves for inertial confinement fusion
Zhou, C. D.; Betti, R.
2008-10-15
It is shown that the ignition condition (Lawson criterion) for inertial confinement fusion (ICF) can be cast in a form dependent on the only two parameters of the compressed fuel assembly that can be measured with existing techniques: the hot spot ion temperature (T{sub i}{sup h}) and the total areal density ({rho}R{sub tot}), which includes the cold shell contribution. A marginal ignition curve is derived in the {rho}R{sub tot}, T{sub i}{sup h} plane and current implosion experiments are compared with the ignition curve. On this plane, hydrodynamic equivalent curves show how a given implosion would perform with respect to the ignition condition when scaled up in the laser-driver energy. For 3<
Helmerhorst, Hendrik J F; Brage, Søren; Warren, Janet; Besson, Herve; Ekelund, Ulf
2012-01-01
Physical inactivity is one of the four leading risk factors for global mortality. Accurate measurement of physical activity (PA) and in particular by physical activity questionnaires (PAQs) remains a challenge. The aim of this paper is to provide an updated systematic review of the reliability and validity characteristics of existing and more recently developed PAQs and to quantitatively compare the performance between existing and newly developed PAQs.A literature search of electronic databases was performed for studies assessing reliability and validity data of PAQs using an objective criterion measurement of PA between January 1997 and December 2011. Articles meeting the inclusion criteria were screened and data were extracted to provide a systematic overview of measurement properties. Due to differences in reported outcomes and criterion methods a quantitative meta-analysis was not possible.In total, 31 studies testing 34 newly developed PAQs, and 65 studies examining 96 existing PAQs were included. Very few PAQs showed good results on both reliability and validity. Median reliability correlation coefficients were 0.62-0.71 for existing, and 0.74-0.76 for new PAQs. Median validity coefficients ranged from 0.30-0.39 for existing, and from 0.25-0.41 for new PAQs.Although the majority of PAQs appear to have acceptable reliability, the validity is moderate at best. Newly developed PAQs do not appear to perform substantially better than existing PAQs in terms of reliability and validity. Future PAQ studies should include measures of absolute validity and the error structure of the instrument. PMID:22938557
2012-01-01
Physical inactivity is one of the four leading risk factors for global mortality. Accurate measurement of physical activity (PA) and in particular by physical activity questionnaires (PAQs) remains a challenge. The aim of this paper is to provide an updated systematic review of the reliability and validity characteristics of existing and more recently developed PAQs and to quantitatively compare the performance between existing and newly developed PAQs. A literature search of electronic databases was performed for studies assessing reliability and validity data of PAQs using an objective criterion measurement of PA between January 1997 and December 2011. Articles meeting the inclusion criteria were screened and data were extracted to provide a systematic overview of measurement properties. Due to differences in reported outcomes and criterion methods a quantitative meta-analysis was not possible. In total, 31 studies testing 34 newly developed PAQs, and 65 studies examining 96 existing PAQs were included. Very few PAQs showed good results on both reliability and validity. Median reliability correlation coefficients were 0.62–0.71 for existing, and 0.74–0.76 for new PAQs. Median validity coefficients ranged from 0.30–0.39 for existing, and from 0.25–0.41 for new PAQs. Although the majority of PAQs appear to have acceptable reliability, the validity is moderate at best. Newly developed PAQs do not appear to perform substantially better than existing PAQs in terms of reliability and validity. Future PAQ studies should include measures of absolute validity and the error structure of the instrument. PMID:22938557
Owen, Nick J; Watkins, James; Kilduff, Liam P; Bevan, Huw R; Bennett, Mark A
2014-06-01
There is a general agreement that the most valid method of measuring peak lower-body mechanical power output (LBPP) in a countermovement jump (CMJ) is by analysis of the corresponding vertical component of the ground reaction force (VGRF)-time history of the jump. However, there is no published standard protocol. The purpose of this study was to establish a standard protocol. The variables necessary to define a valid and reliable CMJ method were: (a) vertical force range, (b) force sampling and integration frequency, (c) method of integration, (d) determination of body weight (BW), and (e) determination of the initiation of the CMJ. Countermovement jumps off a force platform (FP) were performed by 15 male professional rugby players. The 5 variables were then optimized to maximize the reliability and validity of the measure of LBPP. Errors of <1% (p ≤ 0.05) in the measurement of LBPP were obtained using the following specification: (a) 6 times BW (using a 16-bit analog to digital converter), (b) 1,000 Hz, (c) Simpson's rule or the trapezoidal rule, (d) mean VGRF for 1 second of quiet standing immediately before jump signal, and (e) 30 ms before the instant BW ± 5 SD is exceeded after the jump signal. Peak lower-body power output was most sensitive to variables 4 and 5. It was concluded that this study has established a standard protocol for the criterion method of measuring peak power in a CMJ using an FP. As all other estimates and less reliable methods of determining LBPP in a CMJ rely on the FP method for calibration, it is proposed that this protocol be used as the basis of future criterion measures using a FP. PMID:24276298
A New Criterion for Acquisition of Nicotine Self-administration in Rats*
Peartree, Natalie A.; Sanabria, Federico; Thiel, Kenneth J.; Weber, Suzanne M.; Cheung, Timothy H.C.; Neisewander, Janet L.
2012-01-01
Background Acquisition of nicotine self-administration in rodents is relatively difficult to establish and measures of acquisition rate are sometimes confounded by manipulations used to facilitate the process. This study examined acquisition of nicotine self-administration without such manipulations and used mathematical modeling to define the criterion for acquisition. Methods Rats were given 20 daily 2-h sessions occurring 6 days/week in chambers equipped with active and inactive levers. Each active lever press resulted in nicotine reinforcement (0–0.6 mg/kg, IV) and retraction of both levers for a 20-s time out, whereas inactive lever presses had no consequences. Acquisition was defined for individual rats by the higher likelihood of reinforcers obtained across sessions fitting a logistic over a constant function according to the corrected Akaike information criterion (AICc). Results For rats that acquired self-administration, an AICc-based multi-model comparison demonstrated that the asymptote (highest number of reinforcers/session) and mid-point of the acquisition curve (h; the number of sessions necessary to reach half the asymptote) varied by nicotine dose, with both exhibiting a negative relationship (the higher the dose, the lower number of reinforcers and the lower h). Conclusions The modeling approach used in this study provides a way of defining acquisition of nicotine self-administration that takes advantage of all data from individual subjects and the procedure used is sensitive to dose differences in the absence of manipulations that influence acquisition (e.g., food restriction, prior food reinforcement, conditioned reinforcers). PMID:22243759
A stationary criterion to identify the duration of efficient rainfalls to trigger shallow landslide
NASA Astrophysics Data System (ADS)
Vessia, G.; Parise, M.
2012-04-01
framework of a nationwide project by CNR-IRPI, under funds from the National Civil Department, the authors propose in this article a new criterion to identify from rain gauge measures the duration of the rainfalls triggering shallow landslides. The new criterion represents an attempt to identify the duration of the "effective rainfall event" responsible for the landslide occurrence, as reported by newspaper clips and/or in real time web newspapers. At this regard, antecedent precipitations are not taken into account, since the model considers only that amount of rainfall that effectively triggers the slope failure. The model analyses the hourly rainfall time series for at least one month before occurrence of the shallow landslide, using a historical landslide archive covering the time range between 2002 and 2011 in the Lazio Region, central Italy. This archive was obtained by a procedure consisting of the following steps: i) critical scrutiny of chronicles, ii) identification of the landslide site, and iii) retrieval of the rainfall data from the nearest rain gauge station within the pluviometric network provided by the National Department of Civil Protection. The proposed method, for each reported landslide, uses the cumulative function of the rainfall heights and rainfall intensity calculated for different time lag. Then, in order to identify the beginning of the effective rainfall event, two conditions have to be satisfied: (1) the difference in rainfall intensity between two adjacent windows must be very low, and (2) the time series of lack of rainfall must be stationary. When these conditions are met, the initial time of the efficient rainfall necessary to trigger the landslide is established. Such criterion is statistically based according to the rainfall time distribution only. No assumption is needed on the probabilistic distributions of time series of rain/not rain. Such approach has been successfully applied to medium-to-long rainfalls, for which rain/not rain
The One-Meter Criterion for Tsunami Warning: Time for a Reevaluation?
NASA Astrophysics Data System (ADS)
Fryer, G. J.; Weinstein, S.
2013-12-01
The U.S. tsunami warning centers issue warnings when runup is anticipated to exceed one meter. The origins of the one-meter criterion are unclear, though Whitmore, et al (2008) showed from tsunami history that one meter is roughly the threshold above which damage occurs. Recent experiences in Hawaii, however, suggest that the threshold could be raised. Tsunami Warnings were issued for 2010 Chile, 2011 Tohoku, and 2012 Haida Gwaii tsunamis; each exceeded one meter runup somewhere in the State. Evacuation, however, was necessary only in 2011, and even then onshore damage (as opposed to damage from currents) occurred only where runup exceeded 1.5m. During both Chile and Haida Gwaii tsunamis the existing criteria led to unnecessary evacuation. Maximum runup during the Chile tsunami was 1.1m at Hilo's Wailoa Boat Harbor, while the Haida Gwaii tsunami peaked at 1.2m at Honouliwai Bay on Molokai. Both tsunamis caused only minor damage and minimal flooding; in both cases a Tsunami Advisory (i.e., there is no need to evacuate, but stay off the beach and out of the water) would have been adequate. The Advisory was originally developed as an ad hoc response to the mildly threatening 2006 Kuril tsunami and has since been formalized as the product we issue when maximum runup is expected to be 0.3-1.0 m. At the time it was introduced, however, there was no discussion that this new low-level warning might allow the criterion for Tsunami Warning itself to be adjusted. We now suggest that the divide between Advisory and Warning be raised from 1.0 to something greater, possibly 1.2m. If the warning threshold were raised to 1.2m, the over-warning for the Chile tsunami still could not have been avoided. Models calibrated against DART data consistently forecast runup just over 1.2m for that event. For Haida Gwaii, adjusting the models to match the DART data increased the forecast runup to almost 2m, which again meant a warning, though in retrospect we should have been skeptical. The
Chang, Chang; Poole, Kendra L; Teran, Anthony V; Luckman, Scott; Mah, Dennis
2015-01-01
The purpose of this study was to evaluate the effectiveness of full three-dimensional (3D) gamma algorithm for spot scanning proton fields, also referred to as pencil beam scanning (PBS) fields. The difference between the full 3D gamma algorithm and a simplified two-dimensional (2D) version was presented. Both 3D and 2D gamma algorithms are used for dose evaluations of clinical proton PBS fields. The 3D gamma algorithm was implemented in an in-house software program without resorting to 2D interpolations perpendicular to the proton beams at the depths of measurement. Comparison between calculated and measured dose points was car-ried out directly using Euclidian distance in 3D space and the dose difference as a fourth dimension. Note that this 3D algorithm faithfully implemented the original concept proposed by Low et al. (1998) who described gamma criterion using 3D Euclidian distance and dose difference. Patient-specific proton PBS plans are separated into two categories, depending on their optimization method: single-field optimization (SFO) or multifield optimized (MFO). A total of 195 measurements were performed for 58 SFO proton fields. A MFO proton plan with four fields was also calculated and measured, although not used for treatment. Typically three dif-ferent depths were selected from each field for measurements. Each measurement was analyzed by both 3D and 2D gamma algorithms. The resultant 3D and 2D gamma passing rates are then compared and analyzed. Comparison between 3D and 2D gamma passing rates of SFO fields showed that 3D algorithm does show higher passing rates than its 2D counterpart toward the distal end, while little difference is observed at depths away from the distal end. Similar phenomenon in the lateral penumbra was well documented in photon radiation therapy, and in fact brought about the concept of gamma criterion. Although 2D gamma algorithm has been shown to suffice in addressing dose comparisons in lateral penumbra for photon
Cell-mediated immunity to insulin: a new criterion for differentiation of diabetes mellitus?
Asfandiyarova, Nailya S
2012-03-01
Any classification is a step forward and it should help to determine the reason, the course, the prognosis, the treatment of a disease. The current classification of diabetes mellitus (DM) is really very convenient for work, but it has some drawbacks, and the absence of differentiation of type 2 diabetes is the main. The problem is the absence of an adequate criterion, based on pathogenesis for differentiation. We suppose that cell mediated immunity (CMI) to insulin plays the central role in the diabetes genesis. Autoimmune process may be triggered by viruses family Paramyxoviridae, in 10-20% of type 1 diabetes patients the disease is a consequence of direct cytotoxic effect of other viruses to the islet cells of pancreas. In acute phase of viral infection (measles, mumps, parainfluenza) CMI against viruses is developed, in some patients CMI to insulin appeared. We suppose that autoimmune reactions in these cases are the result of cross reaction between viral antigens and insulin. The majorities of patients suppress these reactions and recover from acute infection diseases with the antiviral immunity development and without any complications. Other patients are not able to suppress autoimmune reactions to insulin and pathological process is triggered. Type 1A diabetes is a result of direct CMI to insulin, and this process is responsible for beta-cells destruction; may be type 1B DM is due to the direct cytotoxic effect of other viruses or toxins to them. Some patients with acute viral infection cannot destroy the aggressive clone and they suppress autoimmune reaction to insulin by prostaglandin synthesizing cells (PGSC) or сells with histamine receptors (CHR). As a result of this process the insulin resistance is developed, because these cells or their cytokines form a block to the insulin receptors not only on immunocompetent cells, but in insulin sensitive tissues too. Patients with different reactions to insulin have different courses and outcomes of DM. We
NASA Astrophysics Data System (ADS)
Tang, Xinfeng; Su, Xianli; Uher, Ctirad; Tang's Group Team; Uher's Group Team
2015-03-01
Here we report compound thermoelectric materials (Bi2Te3, Bi2Se3, Cu2Se,Cu2SnSe3, half-Heusler alloys, lead chalcogenides, skutterudites, and magnesium silicides) with thermoelectric properties comparable with materials prepared by the traditional routes of synthesis can be synthesized at a minimal cost and on the time scale of seconds using the self-propagating high temperature synthesis method. Moreover, we found that the criterion often quoted in the literature as the necessary precondition for combustion synthesis, Tad >= 1800 K, is not universal and certainly not applicable to thermoelectric compound semiconductors. Instead, we offer new empirically-based criterion, Tad /Tm , L >1, i.e., the adiabatic temperature must be high enough to melt the lower melting point component, which covers all materials synthesized by self-propagating high temperature synthesis, including the high temperature refractory compounds for which the Tad >= 1800 K criterion was originally developed. Our work opens a new avenue for ultra-fast, low cost, mass production fabrication of efficient thermoelectric materials and the new criterion greatly broadens the scope of materials that can be successfully synthesized by self-propagating high temperature synthesis. We wish to acknowledge support from the National Basic Research Program of China (973 program) under Project 2013CB632502.
ERIC Educational Resources Information Center
Georgia State Dept. of Education, Atlanta. Office of Planning and Development.
Examples are given of criterion-referenced test items in mathematics and reading used at the sixth grade level in Georgia. Three skill areas are identified for mathematics: concept identification, component operations, and problem solving. Tests measure students' ability to: (1) recognize whole numbers, fractions, and decimals; (2) identify…
ERIC Educational Resources Information Center
Naji Qasem, Mamun Ali; Ahmad Gul, Showkeen Bilal
2014-01-01
The study was conducted to know the effect of items direction (positive or negative) on the factorial construction and criterion related validity in Likert scale. The descriptive survey research method was used for the study and the sample consisted of 510 undergraduate students selected by used random sampling technique. A scale developed by…
ERIC Educational Resources Information Center
Tatsuoka, Kikumi
This study examined the appropriateness of the use of criterion referenced tests as a means of controlling an individual student's advancement to the next level of instruction or retention in the current unit in the PLATO Air Force Base Computer-Based Education project at Chanute. The study was also concerned with program evaluation, which…
ERIC Educational Resources Information Center
Roth, Philip L.; Buster, Maury A.; Bobko, Philip
2011-01-01
A number of applied psychologists have suggested that trainability test Black-White ethnic group differences are low or relatively low (e.g., Siegel & Bergman, 1975), though data are scarce. Likewise, there are relatively few estimates of criterion-related validity for trainability tests predicting job performance (cf. Robertson & Downs, 1989). We…
ERIC Educational Resources Information Center
Proger, Barton B.; And Others
Criterion-referenced measurement (CRM) has received increasing attention in regular education. However, it is in education for handicapped children that CRM's flexibility for individualization of both instruction and evaluation become even more fully realized. Research is described on one of the first CRM systems (Individual Achievement Monitoring…
ERIC Educational Resources Information Center
Reeve, Charlie L.; Heggestad, Eric D.; Lievens, Filip
2009-01-01
The assessment of cognitive abilities, whether it is for purposes of basic research or applied decision making, is potentially susceptible to both facilitating and debilitating influences. However, relatively little research has examined the degree to which these factors might moderate the criterion-related validity of cognitive ability tests. To…
NASA Astrophysics Data System (ADS)
Nistor, I.; Pantalé, O.; Caperaa, S.
2006-08-01
The modelling of damage and fracture behaviour under high rates of loadings for metallic structures presents the more and more interests for engineering design, especially for crash phenomena. In order to perform a numerical simulation of such phenomena a crack propagation criterion must be identified using adapted laboratory tests. The objective of this paper is to present a new impact test intended for the identification of a cohesive crack criterion implemented into a home-made FEM code based on Extended Finite Element Method. Therefore, a double-notched specimen is impacted using a gas-gun device in order to obtain different crack paths depending on projectile speed. A post-impact macro-photographic observation allows to measure the crack path, the angles and the advancing length. These experimental results are used as input responses in the identification procedure for determining the crack cohesive criterion parameters. Some experimental results, for an aluminium alloy crack criterion identification, are presented to illustrate the proposed approach.
ERIC Educational Resources Information Center
Livingstone, Holly A.; Day, Arla L.
2005-01-01
Despite the popularity of the concept of emotional intelligence(EI), there is much controversy around its definition, measurement, and validity. Therefore, the authors examined the construct and criterion-related validity of an ability-based EI measure (Mayer Salovey Caruso Emotional Intelligence Test [MSCEIT]) and a mixed-model EI measure…
ERIC Educational Resources Information Center
Meredith, John B., Jr.
The complexity of defining accurate passing scores with a minimum classification error when evaluating criterion-referenced, multiple-choice tests has been a major problem for classroom teachers. Therefore, a practical procedure in which the instructor determines the plausibility of each item option for the minimally acceptable examinee is…
Code of Federal Regulations, 2010 CFR
2010-07-01
... 34 Education 3 2010-07-01 2010-07-01 false What additional criterion does the Secretary apply to applications from organizations and associations? 658.33 Section 658.33 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF...
ERIC Educational Resources Information Center
Daviss, W. Burleson; Birmaher, Boris; Melhem, Nadine A.; Axelson, David A.; Michaels, Shana M.; Brent, David A.
2006-01-01
Background: Previous measures of pediatric depression have shown inconsistent validity in groups with differing demographics, comorbid diagnoses, and clinic or non-clinic origins. The current study re-examines the criterion validity of child- and parent-versions of the Mood and Feelings Questionnaire (MFQ-C, MFQ-P) in a heterogeneous sample of…
NASA Astrophysics Data System (ADS)
Neville, D. J.
T HE PRESENT paper describes a distance criterion for failure at the tips of cracks in materials showing plasticity which, for stress-controlled cleavage on the lower shelf of toughness, is based on consideration of plasticity local to individual crack-initiation sites rather than on the distance from the remote crack tip to a crack-initiation site. For the upper shelf, consideration is of conditions local to voids, but the thermodynamic balance determining the moment of failure is for the macrocrack rather than microcracks, and a criterion of strain is used rather than a criterion of stress. This new criterion of distance or critical distance leads to a good description of temperature-dependent changes in toughness, on the lower shelf where failure is caused by stress-controlled cleavage and on the upper shelf where fracture runs by a strain-controlled ductile mechanism as well as in the region of transition in between, and always on the basis that these changes are due to temperature-dependent changes in yield strength and Young's modulus. A non-dimensional toughness parameter is observed. The present work is in agreement with many accepted ideas about fracture. The significance of the self-similarity of the distributions of stress and strain at the tips of cracks and the over-riding importance of crack-opening displacement in the determination of conditions for propagation are emphasised.
ERIC Educational Resources Information Center
Phemister, Art W.
2010-01-01
The purpose of this study was to evaluate the effectiveness of the Georgia's Choice reading curriculum on third grade science scores on the Georgia Criterion Referenced Competency Test from 2002 to 2008. In assessing the effectiveness of the Georgia's Choice curriculum model this causal comparative study examined the 105 elementary schools that…
Keizer, Joel; Fox, Ronald Forrest
1974-01-01
Doubt is raised concerning the range of validity of a stability criterion for non-equilibrium states which has been proposed by Glansdorff and Prigogine. In the case of a particular autocatalytic reaction, the stability analysis presented by Glansdorff and Prigogine, and by Eigen and by Katchalsky in their reviews of this problem, does not agree with our analysis, which is based upon exact solution of the relevant rate equations. We also find disagreement between the analysis based upon the Glansdorff-Prigogine criterion and our analysis of a second example which involves non-equilibrium steady states. The situation is quite delicate because seemingly innocent approximations (e.g., the use of specialized conditions in the autocatalytic reaction X + Y ⇄ 2X discussed in the sequel) may lead to the impression that the scope of validity of the criterion is wider than it actually is. By considering the stability of the equilibrium state, we conclude that the second differential of the entropy, which is at the heart of the Glansdorff-Prigogine criterion, is likely to be relevant for stability questions close to equilibrium only. PMID:16592132
Huebner, Alan R; Fina, Anthony D
2015-06-01
Computerized classification tests (CCTs) are used to classify examinees into categories in the context of professional certification testing. The term "variable-length" refers to CCTs that terminate (i.e., cease administering items to the examinee) when a classification can be made with a prespecified level of certainty. The sequential probability ratio test (SPRT) is a common criterion for terminating variable-length CCTs, but recent research has proposed more efficient methods. Specifically, the stochastically curtailed SPRT (SCSPRT) and the generalized likelihood ratio criterion (GLR) have been shown to classify examinees with accuracy similar to the SPRT while using fewer items. This article shows that the GLR criterion itself may be stochastically curtailed, resulting in a new termination criterion, the stochastically curtailed GLR (SCGLR). All four criteria-the SPRT, SCSPRT, GLR, and the new SCGLR-were compared using a simulation study. In this study, we examined the criteria in testing conditions that varied several CCT design features, including item bank characteristics, pass/fail threshold, and examinee ability distribution. In each condition, the termination criteria were evaluated according to their accuracy (proportion of examinees classified correctly), efficiency (test length), and loss (a single statistic combing both accuracy and efficiency). The simulation results showed that the SCGLR can yield increased efficiency without sacrificing accuracy, relative to the SPRT, SCSPRT, and GLR in a wide variety of CCT designs. PMID:24907003
ERIC Educational Resources Information Center
Silva, Sharron J.
Test item selection techniques based on traditional item analysis methods were compared to techniques based on item response theory. The consistency of mastery classifications in criterion referenced reading tests was examined. Pretest and posttest data were available for 945 first and second grade students and for 1796 fourth to sixth grade…
ERIC Educational Resources Information Center
Smith, Douglas U.
This study examined the effects of certain item selection methods on the classification accuracy and classification consistency of criterion-referenced instruments. Three item response data sets, representing varying situations of instructional effectiveness, were simulated. Five methods of item selection were then applied to each data set for the…
Nourbakhsh, H.P.; Theofanous, T.G.
1986-09-01
A physically based criterion for predicting thermal stratification due to high-pressure injection in the presence of loop flow is presented. The predictions are consistent with the CREARE 1/5 scale, CREARE 1/2 scale, and HDR test results.
ERIC Educational Resources Information Center
Evers, Kathinka; Kilander, Lena; Lindau, Maria
2007-01-01
The objective of this study was to suggest a new formulation of the core research diagnostic consensus criterion ''loss of insight'' in frontotemporal dementia (FTD). Eight patients with FTD (diagnoses made by interviews, medical and neuropsychological examination, CT scan, and regional cerebral glucose metabolism measured by positron emission…
Clune, Alan
2011-06-01
In 'An Almost Absolute Value in History' John T. Noonan criticizes several attempts to provide a criterion for when an entity deserves rights. These criteria, he argues are either arbitrary or lead to absurd consequence. Noonan proposes human conception as the criterion of rights, and justifies it by appeal to the sharp shift in probability, at conception, of becoming a being possessed of human reason. Conception, then, is when abortion becomes immoral. The article has an historical and a philosophical goal. The historical goal is to carefully present the probability argument in a charitable manner. The philosophical goal is to offer a unique criticism of Noonan's probability argument against abortion. I argue that, even on a very charitable reading of Noonan's argument for the conception criterion, this criterion is also susceptible to charges of arbitrariness and absurdity. Noonan's claim that probability shifts have anything to do with the moral rights of fetuses cannot be made coherent. I also show that there are problems with Noonan's assumptions about moral rights and the potential to become a being possessed of human reason. PMID:19860745
ERIC Educational Resources Information Center
Rikli, Roberta E.; Jones, C. Jessie
2013-01-01
Purpose: To develop and validate criterion-referenced fitness standards for older adults that predict the level of capacity needed for maintaining physical independence into later life. The proposed standards were developed for use with a previously validated test battery for older adults--the Senior Fitness Test (Rikli, R. E., & Jones, C. J.…
Code of Federal Regulations, 2011 CFR
2011-07-01
... 34 Education 3 2011-07-01 2011-07-01 false What additional criterion does the Secretary apply to applications from organizations and associations? 658.33 Section 658.33 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION UNDERGRADUATE INTERNATIONAL STUDIES...
Code of Federal Regulations, 2014 CFR
2014-07-01
... by an organization or association on the basis of the criterion in this section. (a) Need for and... language at the undergraduate level. (b) The Secretary reviews each application for information that shows... studies and the study of modern foreign language at the undergraduate level. (1) The Secretary looks...
Code of Federal Regulations, 2012 CFR
2012-07-01
... 34 Education 3 2012-07-01 2012-07-01 false What additional criterion does the Secretary apply to applications from organizations and associations? 658.33 Section 658.33 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION UNDERGRADUATE INTERNATIONAL STUDIES...
Code of Federal Regulations, 2013 CFR
2013-07-01
... by an organization or association on the basis of the criterion in this section. (a) Need for and... language at the undergraduate level. (b) The Secretary reviews each application for information that shows... studies and the study of modern foreign language at the undergraduate level. (1) The Secretary looks...
ERIC Educational Resources Information Center
Parker, Richard; Tindal, Gerald
The reliability, sensitivity, and criterion-related validity of concept comparison (CC) ratings and computer-derived multidimensional scaling (MDS) maps were studied as ways of assessing reading comprehension. Fifteen experts (2 district coordinators and 13 reading specialists/special education teachers) were included in this study. Reliability…
ERIC Educational Resources Information Center
Maertz, Carl P., Jr.
2012-01-01
In "Reviewing Employee Turnover: Focusing on Proximal Withdrawal States and an Expanded Criterion," Hom, Mitchell, Lee, and Griffeth (2012) brought together many of the most important content and process factors in the employee turnover literature. In this paper, I attempt to clarify the true contributions of this framework for the turnover area…
ERIC Educational Resources Information Center
Holmgren, Byron R.
The paper describes the criterion performance approach, a competency based teacher education program for special education majors in a small, rural church-related private college (Cumberland College in Kentucky). The program serves a relatively large student body with only a few instructors. Entrance requirements are listed as is a recommended…
ERIC Educational Resources Information Center
Willoughby, Michael T.; Blair, Clancy B.; Wirth, R. J.; Greenberg, Mark
2010-01-01
In this study, the authors examined the psychometric properties and criterion validity of a newly developed battery of tasks that were designed to assess executive function (EF) abilities in early childhood. The battery was included in the 36-month assessment of the Family Life Project (FLP), a prospective longitudinal study of 1,292 children…
ERIC Educational Resources Information Center
Darnell, Janice Marie
2012-01-01
The purpose of this correlational study was to examine Georgia's Criterion-Referenced Competency Test (CRCT) scores of 8th grade students and End of Course Test (EOCT) scores of the same students as 9th graders in the areas of language arts and mathematics to test the theory that a relationship exists between the two tests. The study also…
ERIC Educational Resources Information Center
Huang, Chiungjung
2012-01-01
This study examined the discriminant and criterion-related validity of achievement goals in predicting academic achievement. Analysis of 151 studies yielded 172 independent samples (N = 52,986) with correlations among achievement goals and between achievement goals and academic achievement. The discriminant validity of achievement goals in the 2-,…