Finite Larmor radius modification of the Mercier criterion
Connor, J.W.; Tang, W.M.; Allen, L.
1984-04-01
The finite Larmor radius modification of the Suydam criterion involves a competition between stabilizing finite Larmor radius effects and destabilizing curvature. In the case of the toroidal calculation, corresponding to the Mercier criterion, ballooning effects from regions of unfavorable curvature must be taken into account. In the case of a model equilibrium, valid near the magnetic axis, a complete solution is obtained. Results indicate that the amount of finite Larmor radius stabilization needed to overcome the effects of unfavorable average curvature increases as a function of the toroidal ballooning parameter.
NASA Astrophysics Data System (ADS)
Shchepetov, S. V.
2016-11-01
The stability of peeling modes in zero net current stellarator plasma is studied in high poloidal mode number m \\gg 1 approximation. The vacuum region solution is taken into account. Under these conditions in Mercier stable magnetic hill plasmas internal peeling modes are stable. External peeling modes can be unstable, but several limitations on them are found. It is shown that an analytically derived pressure gradient threshold is in reasonable agreement with the experimental observations and numerical calculations. The threshold decreases with increasing poloidal mode number m. It is shown, however, that higher modes may be stabilized due to finite ion Larmor radius effects. For the sake of definiteness, we have investigated peeling mode behavior in Mercier unstable plasma. It is shown that both external and internal peeling modes can be unstable in this regime. However, external and internal peeling modes in this case are definitely different.
NASA Astrophysics Data System (ADS)
Evans, J.
1996-03-01
In 1769 the sixth issue of a new monthly, the Journal des Beaux-Arts et des Sciences, opened an attack on Newton's law of gravitation. In the first article of the June number, Jean Coultaud described pendulum experiments carried out in the mountains of Savoy. The experiments, apparently conducted with great care, seemed to prove that, contrary to Newton's inverse-square law, the weight of an object actually increases with its distance above the surface of the earth. Coultaud's results were soon confirmed by Mercier, as well as by Father Joseph-Etienne Bertier, who performed a completely different sort of experiment in the Church of the Oratory in Paris. These refutations of Newton's law of attraction were in turn refuted by leading mathematicians and mechanicians such as Jean le Rond d'Alembert and Joseph-Jérôme de Lalande. The anomalous gravity experiments provoked an eight-year debate marked by controversy, rising tempers, and a fresh round of experiments by investigators all over France. The debate appears all the more remarkable when one learns that the first round of experiments never took place and that Coultaud and Mercier, the authors of the first papers, were fictitious persons. Obviously, more than a detail of physics was at stake.
Coquart, Jeremy B; Mercier, Daniel; Tabben, Montassar; Bosquet, Laurent
2015-01-01
The aim was to test the influence of sex and specialty (3000, 5000 and 10000 m) on the validity of middle-distance running performance predictions obtained from the Mercier et al.'s nomogram. Consequently, we examined all official French track running rankings for the 3000-, 5000- and 10000-m events (men and women) from 2006 to 2012. A scoring table was used to determine the runners' specialties. Only runners who performed in the three distance events within the same year were included (75 women and 400 men). The Mercier et al.'s nomogram was used to predict one running performance from the other two. The results showed no significant difference between actual and predicted running performances (P = 0.77). Female runners had significantly lower performances than male runners (P < 0.001). Specialty did not influence performances (P = 0.11). Very high correlations were found between actual and predicted performances (0.91 < r < 0.99), with the exception of women (r = 0.85) in 5000 m. Moreover, low limits of agreement were obtained for male and female runners, whatever the specialty. These results support the validity of the nomogram to predict running performance in the 3000-, 5000- and 10000-m events for male and female runners, whatever the specialty. The predicted running performances may be used in training programmes (e.g., to prescribe tempo runs) and competitions (e.g., to establish split times).
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
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.
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.
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
Thermonuclear ignition criterion in ICF
NASA Astrophysics Data System (ADS)
Cheng, Baolian
2010-11-01
The Lawson criterion, which determines the onset of thermonuclear ignition in inertial confinement fusion (ICF), is re-derived in terms of physical measurable quantities: the hot spot ion temperature T and the areal density (ρR) of the deuterium-tritium (DT) gas. From this criterion, an ignition curve is generated in the ρR -T plane. In addition, a minimal required implosion energy for laser-drive and a minimal DT gas mass for a sustainable ignition with respect to the condition are derived.
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…
Kelly criterion revisited: optimal bets
NASA Astrophysics Data System (ADS)
Piotrowski, E. W.; Schroeder, M.
2007-05-01
Kelly criterion, that maximizes the expectation value of the logarithm of wealth for bookmaker bets, gives an advantage over different class of strategies. We use projective symmetries for a explanation of this fact. Kelly's approach allows for an interesting financial interpretation of the Boltzmann/Shannon entropy. A “no-go” hypothesis for big investors is suggested.
Should PTSD Criterion A be retained?
Kilpatrick, Dean G; Resnick, Heidi S; Acierno, Ron
2009-10-01
Criterion A has been controversial since its inception, partially because it performs a key gate keeping function. Major criticisms of Criterion A of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV; American Psychiatric Association, 1994) include that it has resulted in "criterion creep." The authors tested the hypothesis that a nonrestrictive definition would substantially increase posttraumatic stress disorder (PTSD) prevalence by determining PTSD based on Criteria B, C, D, E, and F, without restricting Criterion A in large probability samples of U.S. adolescents and Florida adults. Few PTSD cases occurred in the absence of Criterion A1 events, providing little support for the criterion creep hypothesis. Specific recommendations are to retain Criterion A; permit additional events; consider expanding Criterion A2; consider that either Criterion A1 or A2 be met; and place greater emphasis on Criterion F.
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.
Plasma sheath criterion in thermal electronegative plasmas
Ghomi, Hamid; Khoramabadi, Mansour; Ghorannevis, Mahmod; Shukla, Padma Kant
2010-09-15
The sheath formation criterion in electronegative plasma is examined. By using a multifluid model, it is shown that in a collisional sheath there will be upper as well as lower limits for the sheath velocity criterion. However, the parameters of the negative ions only affect the lower limit.
Non-Linear Transformation of the Criterion.
ERIC Educational Resources Information Center
McNeil, Keith; And Others
The utility of a non-linear transformation of the criterion is established. The Pythagorean Theorem is used as the example to demonstrate the point. The functional relationships may be such (as in the Pythagorean Theorem) that an R-squared of 1.00 cannot be found without making a non-linear transformation of the criterion. The goal of…
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…
An Empirical Failure Criterion for Intact Rocks
NASA Astrophysics Data System (ADS)
Peng, Jun; Rong, Guan; Cai, Ming; Wang, Xiaojiang; Zhou, Chuangbing
2014-03-01
The parameter m i is an important rock property parameter required for use of the Hoek-Brown failure criterion. The conventional method for determining m i is to fit a series of triaxial compression test data. In the absence of laboratory test data, guideline charts have been provided by Hoek to estimate the m i value. In the conventional Hoek-Brown failure criterion, the m i value is a constant for a given rock. It is observed that using a constant m i may not fit the triaxial compression test data well for some rocks. In this paper, a negative exponent empirical model is proposed to express m i as a function of confinement, and this exercise leads us to a new empirical failure criterion for intact rocks. Triaxial compression test data of various rocks are used to fit parameters of this model. It is seen that the new empirical failure criterion fits the test data better than the conventional Hoek-Brown failure criterion for intact rocks. The conventional Hoek-Brown criterion fits the test data well in the high-confinement region but fails to match data well in the low-confinement and tension regions. In particular, it overestimates the uniaxial compressive strength (UCS) and the uniaxial tensile strength of rocks. On the other hand, curves fitted by the proposed empirical failure criterion match test data very well, and the estimated UCS and tensile strength agree well with test data.
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;
Wiener criterion for X-elliptic operators
NASA Astrophysics Data System (ADS)
Tralli, Giulio; Uguzzoni, Francesco
2015-12-01
In this note we prove a Wiener criterion of regularity of boundary points for the Dirichlet problem related to X-elliptic operators in divergence form enjoying the doubling condition and the Poincaré inequality. As a step towards this result, we exhibit some other characterizations of regularity in terms of the capacitary potentials. Finally, we also show that a cone-type criterion holds true in our setting.
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.
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.
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.
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.
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.
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)
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…
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…
43 CFR 2440.2 - General criterion.
Code of Federal Regulations, 2011 CFR
2011-10-01
..., DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SEGREGATION BY CLASSIFICATION Criteria for... possible consistent with the purposes of the classification and the resource values of the lands. ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false General criterion. 2440.2 Section...
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
Criterion to identify Hopf bifurcations in maps of arbitrary dimension.
Wen, Guilin
2005-08-01
The classical Hopf bifurcation criterion is stated in terms of the properties of eigenvalues. In this paper, a criterion without using eigenvalues is proposed for maps of arbitrary dimension. The parameter mechanism of Hopf bifurcation may be explicitly formulated on the basis of the criterion. A numerical example demonstrates that the proposed criterion is preferable to the classical Hopf bifurcation criterion in theoretical analysis and practical applications.
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.
General Stability Criterion for Inviscid Parallel Flow
ERIC Educational Resources Information Center
Sun, Liang
2007-01-01
Arnol'd's second stability theorem is approached from an elementary point of view. First, a sufficient criterion for stability is found analytically as either -[mu][subscript 1] less than U[double prime]/U-U[subscript s] less than 0 or 0 less than U[double prime]/U-U[subscript s] in the flow, where U[subscript s] is the velocity at the inflection…
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 generalized three-dimensional Hoek-Brown strength criterion
NASA Astrophysics Data System (ADS)
Zhang, L.
2008-12-01
Although the Hoek-Brown strength criterion has been widely used in rock mechanics and rock engineering, it does not take account of the influence of the intermediate principal stress. Much evidence, however, has been accumulating to indicate that the intermediate principal stress does influence the rock strength in many instances. Therefore, researchers have developed three-dimensional (3D) versions of the Hoek-Brown strength criterion. In this paper, three existing 3D versions of the Hoek-Brown strength criterion are reviewed and evaluated. The evaluation shows that all of the three 3D versions of the Hoek-Brown strength criterion have limitations. To address the limitations, a generalized 3D Hoek-Brown criterion is proposed by modifying the generalized Hoek-Brown strength criterion. The proposed 3D criterion not only inherits the advantages of the Hoek-Brown strength criterion but can take account of the influence of the intermediate principal stress. At a 2D stress state (triaxial or biaxial), the proposed 3D criterion will simply reduce to the form of the generalized Hoek-Brown strength criterion. To validate the proposed 3D strength criterion, polyaxial or true triaxial compression test data of intact rocks and jointed rock masses has been collected from the published literature. Predictions of the proposed generalized 3D Hoek-Brown strength criterion are in good agreement with the test data for a range of different rock types. The difference of the proposed generalized 3D Hoek-Brown strength criterion from and its advantages over the existing 3D versions of the Hoek-Brown strength criterion are also discussed. It should be noted that the proposed 3D criterion is empirical in nature because it is an extension of the 2D Hoek-Brown strength criterion, which is empirical. Because of the non-convexity of the yield surface for a biaxial stress state, the proposed 3D criterion may have problems with some stress paths.
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).
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 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
A Rosenzweig-MacArthur (1963) Criterion for the Chemostat.
Lindström, Torsten; 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.
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.
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.
A geometric criterion for adiabatic chaos
Kaper, T.J. ); Kovacic, G. )
1994-03-01
Chaos in adiabatic Hamiltonian systems is a recent discovery and a pervasive phenomenon in physics. In this work, a geometric criterion is discussed based on the theory of action from classical mechanics to detect the existence of Smale horseshoe chaos in adiabatic systems. It is used to show that generic adiabatic planar Hamiltonian systems exhibit stochastic dynamics in large regions of phase space. To illustrate the method, results are obtained for three problems concerning relativistic particle dynamics, fluid mechanics, and passage through resonance, results which either could not be obtained with existing methods, or which were difficult and analytically impractical to obtain with them.
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.…
Computerized Adaptive Testing Using the Nearest-Neighbors Criterion.
ERIC Educational Resources Information Center
Cheng, Philip E.; Liou, Michelle
2003-01-01
Proposed and evaluated a modified version of the maximum Fisher information (MFI) criterion called the nearest-neighbors (NN) criterion. Simulation study results show that NN procedure improved to a moderate extent the undesirable item exposure rates associated with the MFI criterion and keeps sufficient precision in theta estimates. (SLD)
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
Maximum neighborhood margin criterion in face recognition
NASA Astrophysics Data System (ADS)
Han, Pang Ying; Teoh, Andrew Beng Jin
2009-04-01
Feature extraction is a data analysis technique devoted to removing redundancy and extracting the most discriminative information. In face recognition, feature extractors are normally plagued with small sample size problems, in which the total number of training images is much smaller than the image dimensionality. Recently, an optimized facial feature extractor, maximum marginal criterion (MMC), was proposed. MMC computes an optimized projection by solving the generalized eigenvalue problem in a standard form that is free from inverse matrix operation, and thus it does not suffer from the small sample size problem. However, MMC is essentially a linear projection technique that relies on facial image pixel intensity to compute within- and between-class scatters. The nonlinear nature of faces restricts the discrimination of MMC. Hence, we propose an improved MMC, namely maximum neighborhood margin criterion (MNMC). Unlike MMC, which preserves global geometric structures that do not perfectly describe the underlying face manifold, MNMC seeks a projection that preserves local geometric structures via neighborhood preservation. This objective function leads to the enhancement of classification capability, and this is testified by experimental results. MNMC shows its performance superiority compared to MMC, especially in pose, illumination, and expression (PIE) and face recognition grand challenge (FRGC) databases.
Maximum Correntropy Criterion for Robust Face Recognition.
He, Ran; Zheng, Wei-Shi; Hu, Bao-Gang
2011-08-01
In this paper, we present a sparse correntropy framework for computing robust sparse representations of face images for recognition. Compared with the state-of-the-art l(1)norm-based sparse representation classifier (SRC), which assumes that noise also has a sparse representation, our sparse algorithm is developed based on the maximum correntropy criterion, which is much more insensitive to outliers. In order to develop a more tractable and practical approach, we in particular impose nonnegativity constraint on the variables in the maximum correntropy criterion and develop a half-quadratic optimization technique to approximately maximize the objective function in an alternating way so that the complex optimization problem is reduced to learning a sparse representation through a weighted linear least squares problem with nonnegativity constraint at each iteration. Our extensive experiments demonstrate that the proposed method is more robust and efficient in dealing with the occlusion and corruption problems in face recognition as compared to the related state-of-the-art methods. In particular, it shows that the proposed method can improve both recognition accuracy and receiver operator characteristic (ROC) curves, while the computational cost is much lower than the SRC algorithms.
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 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.
A new three-dimensional Hoek-Brown strength criterion
NASA Astrophysics Data System (ADS)
Jiang, Hua; Xie, Yong-Li
2012-04-01
The Hoek-Brown (HB) strength criterion has been widely applied to the estimation of strength of intact rock and rock mass, while evolving ever since. However, negligence of the effect of the intermediate principal stress still remains in the criterion's latest version. At the same time, several three-dimensional (3D) HB strength, which can takes into account the influence of the intermediate principal stress, have already been proposed, among which the 3D HB criterion proposed by Zhang and Zhu seems to be the most reasonable one. However, the Zhang 3D HB criterion may have problems with some stress path close to triaxial extension state because of the non-convexity characteristic of its failure surface. In this paper, a new 3D HB strength criterion is presented based on a generalized form of the HB criterion, which also considers the effect of the intermediate principal stress and inherits all the merits of the original version of the HB criterion. In addition, this new criterion can remedy to some extent the shortcomings observed in the Zhang 3D HB criterion. Polyaxial tests for five different rocks from published literatures are used for evaluating this new criterion and comparing it with the Zhang 3D HB criterion. The results show that this new criterion may over-predict or under-predict the polyaxial strength of rocks but the errors are relatively small, and similar results are also found for the Zhang 3D HB criterion, which one is better depends on the type of the rock under estimation.
The neck injury criterion: future considerations.
Croft, Arthur C; Herring, Patti; Freeman, Michael D; Haneline, Michael T
2002-03-01
The cost of whiplash injuries--both in dollars spent for medical care and disability, and in terms of human suffering--are quite high in westernized nations. This is of particular interest both from a public health perspective and a general societal one because the disorder is theoretically preventable: in the very least it can be minimized. This can be achieved with crash prevention strategies and improvements in vehicle safety design--especially with more effective seat back and head restraint systems. Toward the goal of developing a gold standard for safety research in this area, a neck injury criterion (NIC) was proposed by Boström et al. in 1996 (Boström O., Svennson, M.Y., Aldman, B. et al., 1996. In: Proceedings of the International Conference on the Biomechanics of Impact, Dublin, Ireland). This criterion considers the relative horizontal acceleration and velocity between the bottom (T1) and top (C1) of the cervical spine and has face validity based on current literature. However, the NIC has still not been subjected to rigorous scientific investigation or validation in terms of its representativeness of human occupant injury. Such investigation should specifically consider, first, whether the NIC provides an adequate proxy for all potential neck injuries due to whiplash and, secondly, whether the proposed threshold value of 15 m2/s2 is an appropriate level for the stated goal. Based on a review of recent literature, recent human volunteer crash tests by Wheeler et al. and the those of the Spine Research Institute of San Diego, and based on mathematical MADYMO analysis of the first real world crash pulse data, it appears that the threshold for acute injury in the general population is likely to require a lowering of the originally proposed NIC value, and additional parameters, such as considering a forward rebound phase or neck extension criteria may be necessary. The conclusions of this paper should be considered preliminary because the numbers of crash
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.
Group average difference: a termination criterion for active contour.
Chuah, Tong Kuan; Lim, Jun Hong; Poh, Chueh Loo
2012-04-01
This paper presents a termination criterion for active contour that does not involve alteration of the energy functional. The criterion is based on the area difference of the contour during evolution. In this criterion, the evolution of the contour terminates when the area difference fluctuates around a constant. The termination criterion is tested using parametric gradient vector flow active contour with contour resampling and normal force selection. The usefulness of the criterion is shown through its trend, speed, accuracy, shape insensitivity, and insensitivity to contour resampling. The metric used in the proposed criterion demonstrated a steadily decreasing trend. For automatic implementation in which different shapes need to be segmented, the proposed criterion demonstrated almost 50% and 60% total time reduction while achieving similar accuracy as compared with the pixel movement-based method in the segmentation of synthetic and real medical images, respectively. Our results also show that the proposed termination criterion is insensitive to shape variation and contour resampling. The criterion also possesses potential to be used for other kinds of snakes.
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.
Adaptive criterion setting in perceptual decision making.
Stüttgen, Maik C; Yildiz, Ali; Güntürkün, Onur
2011-09-01
Pigeons responded in a perceptual categorization task with six different stimuli (shades of gray), three of which were to be classified as "light" or "dark", respectively. Reinforcement probability for correct responses was varied from 0.2 to 0.6 across blocks of sessions and was unequal for correct light and dark responses. Introduction of a new reinforcement contingency resulted in a biphasic process of adjustment: First, choices were strongly biased towards the favored alternative, which was followed by a shift of preference back towards unbiased choice allocation. The data are well described by a signal detection model in which adjustment to a change in reinforcement contingency is modeled as the change of a criterion along a decision axis with fixed stimulus distributions. Moreover, the model shows that pigeons, after an initial overadjustment, distribute their responses almost optimally, although the overall benefit from doing so is extremely small. The strong and swift effect of minute changes in overall reinforcement probability precludes a choice strategy directly maximizing expected value, contrary to the assumption of signal detection theory. Instead, the rapid adjustments observed can be explained by a model in which reinforcement probabilities for each action, contingent on perceived stimulus intensity, determine choice allocation.
Quality criterion for digital still camera
NASA Astrophysics Data System (ADS)
Bezryadin, Sergey
2007-02-01
The main quality requirements for a digital still camera are color capturing accuracy, low noise level, and quantum efficiency. Different consumers assign different priorities to the listed parameters, and camera designers need clearly formulated methods for their evaluation. While there are procedures providing noise level and quantum efficiency estimation, there are no effective means for color capturing accuracy estimation. Introduced in this paper criterion allows to fill this gap. Luther-Ives condition for correct color reproduction system became known in the beginning of the last century. However, since no detector system satisfies Luther-Ives condition, there are always stimuli that are distinctly different for an observer, but which detectors are unable to distinguish. To estimate conformity of a detector set with Luther-Ives condition and calculate a measure of discrepancy, an angle between detector sensor sensitivity and Cohen's Fundamental Color Space may be used. In this paper, the divergence angle is calculated for some typical CCD sensors and a demonstration provided on how this angle might be reduced with a corrective filter. In addition, it is shown that with a specific corrective filter Foveon sensors turn into a detector system with a good Luther-Ives condition compliance.
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
Criterion Referenced Test: Some Advantages and Disadvantages for Science Instruction
ERIC Educational Resources Information Center
Esler, William K.; Dziuban, Charles D.
1974-01-01
Discusses the criterion referenced test and focuses on such questions as What is it? What are the advantages to be gained from a performance-based curriculum and criterion reference evaluation procedures? What are the disadvantages? The Science - A Process Approach program is identified as the most complete and tested example of the use of…
A Rationale for Criterion-Referenced Proficiency Testing
ERIC Educational Resources Information Center
Clifford, Ray
2016-01-01
This article summarizes some of the technical issues that add to the complexity of language testing. It focuses in particular on the criterion-referenced nature of the ACTFL Proficiency Guidelines-Speaking; and it proposes a criterion-referenced interpretation of the ACTFL guidelines for reading and listening. It then demonstrates how using…
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…
46 CFR 174.020 - Alternate intact stability criterion.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 46 Shipping 7 2011-10-01 2011-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...
46 CFR 174.020 - Alternate intact stability criterion.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 46 Shipping 7 2013-10-01 2013-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...
46 CFR 174.020 - Alternate intact stability criterion.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 46 Shipping 7 2012-10-01 2012-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...
46 CFR 174.020 - Alternate intact stability criterion.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 7 2014-10-01 2014-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...
46 CFR 174.020 - Alternate intact stability criterion.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 46 Shipping 7 2010-10-01 2010-10-01 false Alternate intact stability criterion. 174.020 Section 174.020 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY... Alternate intact stability criterion. A barge need not comply with § 174.015 and subparts C and E of...
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 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.
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 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…
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
Risk acceptance criterion for tanker oil spill risk reduction measures.
Psarros, George; Skjong, Rolf; Vanem, Erik
2011-01-01
This paper is aimed at investigating whether there is ample support for the view that the acceptance criterion for evaluating measures for prevention of oil spills from tankers should be based on cost-effectiveness considerations. One such criterion can be reflected by the Cost of Averting a Tonne of oil Spilt (CATS) whereas its target value is updated by elaborating the inherent uncertainties of oil spill costs and establishing a value for the criterion's assurance factor. To this end, a value of $80,000/t is proposed as a sensible CATS criterion and the proposed value for the assurance factor F=1.5 is supported by the retrieved Protection and Indemnity (P&I) Clubs' Annual Reports. It is envisaged that this criterion would allow the conversion of direct and indirect costs into a non-market value for the optimal allocation of resources between the various parties investing in shipping. A review of previous cost estimation models on oil spills is presented and a probability distribution (log-normal) is fitted on the available oil spill cost data, where it should be made abundantly clear that the mean value of the distribution is used for deriving the updated CATS criterion value. However, the difference between the initial and the updated CATS criterion in the percentiles of the distribution is small. It is found through the current analysis that results are partly lower than the predicted values from the published estimation models. The costs are also found to depend on the type of accident, which is in agreement with the results of previous studies. Other proposals on acceptance criteria are reviewed and it is asserted that the CATS criterion can be considered as the best candidate. Evidence is provided that the CATS approach is practical and meaningful by including examples of successful applications in actual risk assessments. Finally, it is suggested that the criterion may be refined subject to more readily available cost data and experience gained from future
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.
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.
Energy Criterion for the Spectral Stability of Discrete Breathers
NASA Astrophysics Data System (ADS)
Kevrekidis, Panayotis G.; Cuevas-Maraver, Jesús; Pelinovsky, Dmitry E.
2016-08-01
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.
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
Industry Software Trustworthiness Criterion Research Based on Business Trustworthiness
NASA Astrophysics Data System (ADS)
Zhang, Jin; Liu, Jun-fei; Jiao, Hai-xing; Shen, Yi; Liu, Shu-yuan
To industry software Trustworthiness problem, an idea aiming to business to construct industry software trustworthiness criterion is proposed. Based on the triangle model of "trustworthy grade definition-trustworthy evidence model-trustworthy evaluating", the idea of business trustworthiness is incarnated from different aspects of trustworthy triangle model for special industry software, power producing management system (PPMS). Business trustworthiness is the center in the constructed industry trustworthy software criterion. Fusing the international standard and industry rules, the constructed trustworthy criterion strengthens the maneuverability and reliability. Quantitive evaluating method makes the evaluating results be intuitionistic and comparable.
Norm Referenced and Criterion Based Measures with Preschoolers
ERIC Educational Resources Information Center
MacTurk, Robert H.; Neisworth, John T.
1978-01-01
Seventeen handicapped and nonhandicapped preschool children were given both the norm referenced Gesell Developmental Schedules and the criterion based HICOMP progress measure on a quarterly (10 week) basis. (Author/SBH)
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.
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.
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.
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.
Development of failure criterion for Kevlar-epoxy fabric laminates
NASA Technical Reports Server (NTRS)
Tennyson, R. C.; Elliott, W. G.
1984-01-01
The development of the tensor polynomial failure criterion for composite laminate analysis is discussed. In particular, emphasis is given to the fabrication and testing of Kevlar-49 fabric (Style 285)/Narmco 5208 Epoxy. The quadratic-failure criterion with F(12)=0 provides accurate estimates of failure stresses for the Kevlar/Epoxy investigated. The cubic failure criterion was re-cast into an operationally easier form, providing the engineer with design curves that can be applied to laminates fabricated from unidirectional prepregs. In the form presented no interaction strength tests are required, although recourse to the quadratic model and the principal strength parameters is necessary. However, insufficient test data exists at present to generalize this approach for all undirectional prepregs and its use must be restricted to the generic materials investigated to-date.
Re-examining death: against a higher brain criterion.
Fisher, J
1999-01-01
While there is increasing pressure on scarce health care resources, advances in medical science have blurred the boundary between life and death. Individuals can survive for decades without consciousness and individuals whose whole brains are dead can be supported for extended periods. One suggested response is to redefine death, justifying a higher brain criterion for death. This argument fails because it conflates two distinct notions about the demise of human beings--the one, biological and the other, ontological. Death is a biological phenomenon. This view entails the rejection of a higher brain criterion of death. Moreover, I claim that the justification of the whole brain (or brain stem) criterion of death is also cast into doubt by these advances in medical science. I proceed to argue that there is no need to redefine death in order to identify which treatments ought to be provided for the permanently and irreversibly unconscious. There are already clear treatment guidelines. PMID:10635501
Evaluation of failure criterion for graphite/epoxy fabric laminates
NASA Technical Reports Server (NTRS)
Tennyson, R. C.; Wharram, G. E.
1985-01-01
The development and application of the tensor polynomial failure criterion for composite laminate analysis is described. Emphasis is given to the fabrication and testing of Narmco Rigidite 5208-WT300, a plain weave fabric of Thornel 300 Graphite fibers impregnated with Narmco 5208 Resin. The quadratic-failure criterion with F sub 12=0 provides accurate estimates of failure stresses for the graphite/epoxy investigated. The cubic failure criterion was recast into an operationally easier form, providing design curves that can be applied to laminates fabricated from orthotropic woven fabric prepregs. In the form presented, no interaction strength tests are required, although recourse to the quadratic model and the principal strength parameters is necessary. However, insufficient test data exist at present to generalize this approach for all prepreg constructions, and its use must be restricted to the generic materials and configurations investigated to date.
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.
A bilinear failure criterion for mixed-mode delamination
NASA Technical Reports Server (NTRS)
Reeder, James R.
1993-01-01
Many different failure criteria have been suggested for mixed-mode delamination toughness, but few sets of mixed-mode data exist that are consistent over the full range of Mode 1 opening load to Mode 2 shear load range. The mixed-mode bending (MMB) test was used to measure the delamination toughness of a brittle epoxy composite, a state-of-the-art toughened epoxy composite, and a tough thermoplastic composite over the full mixed-mode range. To gain insight into the different failure responses of the different materials, the delamination fracture surfaces were also examined. An evaluation of several failure criteria that have been reported in the literature was performed, and the range of responses modeled by each criterion was analyzed. A bilinear failure criterion was introduced based on a change in the failure mechanism observed from the delamination surfaces. The different criteria were compared to the failure response of the three materials tested. The responses of the two epoxies were best modeled with the new bilinear failure criterion. The failure response of the tough thermoplastic composite could be modeled well with the bilinear criterion but could also be modeled with the more simple linear failure criterion. Since the materials differed in their mixed-mode failure response, mixed-mode delamination testing will be needed to characterize a composite material. This paper presents consistent sets of mixed-mode data, provides a critical evaluation of the mixed-mode failure criteria, and should provide general guidance for selecting an appropriate criterion for other materials.
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
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.
On Criterion Weighting in the DSM-IV.
ERIC Educational Resources Information Center
Langenbucher, James W.; And Others
1996-01-01
Six alternately weighted algorithms for diagnosing alcohol dependency in accordance with the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) based on statistical, unit, rational and random criterion weighting systems, were used to predict an array of concurrent validators and six-month drinking outcomes in a regional clinical…
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…
Slope Stability Analysis Using Limit Equilibrium Method in Nonlinear Criterion
Lin, Hang; Zhong, Wenwen; Xiong, Wei; Tang, Wenyu
2014-01-01
In slope stability analysis, the limit equilibrium method is usually used to calculate the safety factor of slope based on Mohr-Coulomb criterion. However, Mohr-Coulomb criterion is restricted to the description of rock mass. To overcome its shortcomings, this paper combined Hoek-Brown criterion and limit equilibrium method and proposed an equation for calculating the safety factor of slope with limit equilibrium method in Hoek-Brown criterion through equivalent cohesive strength and the friction angle. Moreover, this paper investigates the impact of Hoek-Brown parameters on the safety factor of slope, which reveals that there is linear relation between equivalent cohesive strength and weakening factor D. However, there are nonlinear relations between equivalent cohesive strength and Geological Strength Index (GSI), the uniaxial compressive strength of intact rock σci, and the parameter of intact rock mi. There is nonlinear relation between the friction angle and all Hoek-Brown parameters. With the increase of D, the safety factor of slope F decreases linearly; with the increase of GSI, F increases nonlinearly; when σci is relatively small, the relation between F and σci is nonlinear, but when σci is relatively large, the relation is linear; with the increase of mi, F decreases first and then increases. PMID:25147838
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…
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…
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…
Estimating the Reliability of Criterion-Referenced Tests before Administration.
ERIC Educational Resources Information Center
Chase, Clint
1996-01-01
Classical procedures for calculating the two indices of decision consistency (P and Kappa) for criterion-referenced tests require two testings on each child. Huynh, Peng, and Subkoviak have presented one-testing procedures for these indices. These indices can be estimated without any test administration using Ebel's estimates of the mean, standard…
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…
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…
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…
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,…
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.
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
A frequency-domain transient stability criterion for normal contingencies
Marceau, R.J.; Rizzi, J.C.; Mailhot, R.
1995-08-01
In a previous paper, a simple frequency-domain stability criterion was proposed for networks near the stability limit subjected to a 3-phase fault with no loss of line. The criterion can be summarized as follows: if a system is stable, the phase angle of the Fourier transform of a network`s transient voltage response exhibits a clockwise polar plot behavior at all buses (i.e. for increasing frequency); if the system is unstable, it exhibits a counterclockwise behavior in at least one location. Though these results are of interest, the criterion would be of greater practical use in mechanizing dynamic security analysis if it could be extended to the types of contingencies actually used in security analysis, namely normal contingencies. Normal contingencies are commonly defined as the loss of any element in a power system, either spontaneously or preceded by a fault, and such changes in topology impact post-contingency steady-state voltages in addition to their transient behavior. The present paper shows how such cases can be treated, thereby extending the applicable range of the criterion to normal contingencies.
Integral criterion for selecting nonlinear crystals for frequency conversion
Grechin, Sergei G
2009-02-28
An integral criterion, which takes into account all parameters determining the conversion efficiency, is offered for selecting nonlinear crystals for frequency conversion. The angular phase-matching width is shown to be related to the beam walk-off angle. (nonlinear optical phenomena)
Estimation of Validity for Criterion-Referenced Tests.
ERIC Educational Resources Information Center
Crambert, Albert C.
It is usually assumed that the procedures followed in developing criterion-referenced (CR) educational achievement tests ensure their content validity. This assumption is reasonable for the class of "domain-specified" CR tests, in which the item domain is completely specified by item generation rules. However, most CR tests are of the…
Is the Discrepancy Criterion for Defining Developmental Disorders Valid?
ERIC Educational Resources Information Center
Dyck, Murray J.; Hay, David; Anderson, Mike; Smith, Leigh M.; Piek, Jan; Hallmayer, Joachim
2004-01-01
Background: Most developmental disorders are defined by an achievement discrepancy in which achievement on one or more specific abilities is substantially less than a person's measured intelligence. We evaluated the validity of this discrepancy criterion by assessing parameters that determine variability across abilities and by assessing…
Family Living. 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 eight terminal objectives for a family living course for 10th, 11th, and 12th grade students. The materials were developed for a semester or 1-year course designed to prepare students (1) to exhibit knowledge of the past, present, and future…
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…
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…
The Role of Reliability in Criterion-Referenced Tests.
ERIC Educational Resources Information Center
Kane, Michael T.
1986-01-01
These analyses suggest that if a criterion-referenced test had a reliability (defined in terms of internal consistency) below 0.5, a simple a priori procedure would provide better estimates of students' universe scores than would individual observed scores. (Author/LMO)
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.…
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…
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…
NASA Astrophysics Data System (ADS)
Madou, Komlanvi; Leblond, Jean-Baptiste
2012-05-01
The aim of this paper is to fully determine the parameters of the approximate homogenized yield criterion for porous ductile solids containing arbitrary ellipsoidal cavities proposed in Part I. This is done through improvements of the limit-analysis of some representative hollow cell presented there. The improvements are of two kinds. For hydrostatic loadings, the limit-analysis is refined by performing micromechanical finite element computations in a number of significant cases, so as to replace Leblond and Gologanu (2008)'s trial velocity field representing the expansion of the void by the exact, numerically determined one. For deviatoric loadings, limit-analysis is dropped and direct use is made of some general rigorous results for nonlinear composites derived by Ponte-Castaneda (1991), Willis (1991) and Michel and Suquet (1992) using the earlier work of Willis (1977) and the concept of "linear comparison material". This hybrid approach is thought to lead to the best possible expressions of the yield criterion parameters. The criterion proposed reduces to (variants of) classical approximate criteria proposed by Gurson (1977) and Gologanu et al. (1993, 1994, 1997) in the specific cases of spherical or spheroidal, prolate or oblate cavities. An overview of the validation of this criterion through micromechanical finite element computations is finally presented.
Experimental research on ductile fracture criterion in metal forming
NASA Astrophysics Data System (ADS)
Yu, Song; Feng, Weiming
2011-09-01
Ductile fracture criterion is key limitation parameter in material forming. Accuracy predicting surface and internal failure in plastic deformation process affects on the technology design of workpiece and die greatly. Tension, compression, torsion and shearing test on 45# steel are utilized for providing the experimental values of the critical values at fracture, and 11 widely used ductile fracture criterion are selected to simulate the physical experiments and their relative accuracy for predicting and quantifying fracture initiation sites are investigated. The comparing results show that metal forming process under high triaxiality can be estimated successively using both Normalized Cockcroft-latham and the Brozzo ductile fracture criteria, but the Ayada and general Rice-Tracey model work very well for the low triaxiality cases.
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.
A Bayesian A-optimal and model robust design criterion.
Zhou, Xiaojie; Joseph, Lawrence; Wolfson, David B; Bélisle, Patrick
2003-12-01
Suppose that the true model underlying a set of data is one of a finite set of candidate models, and that parameter estimation for this model is of primary interest. With this goal, optimal design must depend on a loss function across all possible models. A common method that accounts for model uncertainty is to average the loss over all models; this is the basis of what is known as Läuter's criterion. We generalize Läuter's criterion and show that it can be placed in a Bayesian decision theoretic framework, by extending the definition of Bayesian A-optimality. We use this generalized A-optimality to find optimal design points in an environmental safety setting. In estimating the smallest detectable trace limit in a water contamination problem, we obtain optimal designs that are quite different from those suggested by standard A-optimality.
On thermonuclear ignition criterion at the National Ignition Facility
NASA Astrophysics Data System (ADS)
Cheng, Baolian; Kwan, Thomas J. T.; Wang, Yi-Ming; Batha, Steven H.
2014-10-01
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.
A Generalized Evolution Criterion in Nonequilibrium Convective Systems
NASA Astrophysics Data System (ADS)
Ichiyanagi, Masakazu; Nisizima, Kunisuke
1989-04-01
A general evolution criterion, applicable to transport processes such as the conduction of heat and mass diffusion, is obtained as a direct version of the Le Chatelier-Braun principle for stationary states. The present theory is not based on any radical departure from the conventional one. The generalized theory is made determinate by proposing the balance equations for extensive thermodynamic variables which will reflect the character of convective systems under the assumption of local equilibrium. As a consequence of the introduction of source terms in the balance equations, there appear additional terms in the expression of the local entropy production, which are bilinear in terms of the intensive variables and the sources. In the present paper, we show that we can construct a dissipation function for such general cases, in which the premises of the Glansdorff-Prigogine theory are accumulated. The new dissipation function permits us to formulate a generalized evolution criterion for convective 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.
Bayesian Case-deletion Model Complexity and Information Criterion
Zhu, Hongtu; Ibrahim, Joseph G.; Chen, Qingxia
2015-01-01
We establish a connection between Bayesian case influence measures for assessing the influence of individual observations and Bayesian predictive methods for evaluating the predictive performance of a model and comparing different models fitted to the same dataset. Based on such a connection, we formally propose a new set of Bayesian case-deletion model complexity (BCMC) measures for quantifying the effective number of parameters in a given statistical model. Its properties in linear models are explored. Adding some functions of BCMC to a conditional deviance function leads to a Bayesian case-deletion information criterion (BCIC) for comparing models. We systematically investigate some properties of BCIC and its connection with other information criteria, such as the Deviance Information Criterion (DIC). We illustrate the proposed methodology on linear mixed models with simulations and a real data example. PMID:26180578
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.
A Lindemann criterion for the atomization of metals
NASA Astrophysics Data System (ADS)
Batsanov, S. S.
2012-11-01
A thermodynamic variation of the Lindemann criterion for the vaporization of metals is proposed. It is shown that the critical amplitude of vibrations of atoms at the boiling point averages 1.42 bond lengths. Close values of interatomic distances result from the Vinet universal equation for the atomization of metals under the action of high temperatures (1.48) and negative pressures (1.50). The last value corresponds to the Van der Waals distances between metal atoms.
Criterion for mixed mode fracture in composite bonded joints
NASA Technical Reports Server (NTRS)
Mall, S.; Kochhar, N. K.
1986-01-01
A study was undertaken to characterize the debond growth mechanism of adhesively bonded composite joints under mode I, mixed mode I-II, and mode II static loadings. The bonded system consisted of graphite-epoxy composite adherends bonded with a toughened epoxy adhesive. The mode I, mode II and mixed mode I-II fracture energies of the tested adhesives were found to be equal to each other. The criterion for mixed mode fracture in composite bonded joints was found.
An elementary proof of a criterion for linear disjointness
NASA Astrophysics Data System (ADS)
Dobbs, David E.
2013-06-01
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 K-vector space basis of F is linearly independent over L. The material in this note could serve as enrichment material for the unit on fields in a first course on abstract algebra.
Kinetic theory of the presheath and the Bohm criterion
NASA Astrophysics Data System (ADS)
Baalrud, S. D.; Hegna, C. C.
2011-04-01
A kinetic theory of the Bohm criterion is developed that is based on positive-exponent velocity moments of the plasma kinetic equation. This result is contrasted with the conventional kinetic Bohm criterion that is based on a v-1 moment of the Vlasov equation. The salient difference between the two results is that low-velocity particles dominate in the conventional theory, but are essentially unimportant in the new theory. It is shown that the derivation of the conventional kinetic Bohm criterion is flawed. Low-velocity particles can cause unphysical divergences in the conventional theory. These divergent contributions are avoided with this new approach. The two theories are compared using example distribution functions from previous presheath models. The importance of ion-ion and electron-electron collisions to determining the particle distribution functions throughout the presheath is also discussed. A kinetic equation that accounts for wave-particle scattering by convective instabilities is used to show that ion-acoustic instabilities in the presheath of low temperature plasmas (where Te Gt Ti) can cause both ions and electrons to obtain Maxwellian distribution functions near the sheath.
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
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
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.
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
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.
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.
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.
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.
Application of the Kelly Criterion to Ornstein-Uhlenbeck Processes
NASA Astrophysics Data System (ADS)
Lv, Yingdong; Meister, Bernhard K.
In this paper, we study the Kelly criterion in the continuous time framework building on the work of E.O. Thorp and others. The existence of an optimal strategy is proven in a general setting and the corresponding optimal wealth process is found. A simple formula is provided for calculating the optimal portfolio for a set of price processes satisfying some simple conditions. Properties of the optimal investment strategy for assets governed by multiple Ornstein-Uhlenbeck processes are studied. The paper ends with a short discus-sion of the implications of these ideas for financial markets.
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
Criterion for mixed mode fracture in composite bonded joints
NASA Technical Reports Server (NTRS)
Mall, S.; Kochhar, N. K.
1986-01-01
A study was undertaken to characterize the debond growth mechanism of adhesively bonded composite joints under mode I, mixed mode I-II, and mode II static loadings. The bonded system consisted of graphite/epoxy (T300/5208) composite adherends bonded with a toughened epoxy (EC 3445) adhesive. The mode I, mode II and mixed-mode I-II fracture energies of the tested adhesive were found to be equal to each other. Furthermore, the criterion for mixed mode fracture in composite bonded joints was determined.
Shear velocity criterion for incipient motion of sediment
Simoes, Francisco J.
2014-01-01
The prediction of incipient motion has had great importance to the theory of sediment transport. The most commonly used methods are based on the concept of critical shear stress and employ an approach similar, or identical, to the Shields diagram. An alternative method that uses the movability number, defined as the ratio of the shear velocity to the particle’s settling velocity, was employed in this study. A large amount of experimental data were used to develop an empirical incipient motion criterion based on the movability number. It is shown that this approach can provide a simple and accurate method of computing the threshold condition for sediment motion.
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.
Criterion for SLOCC equivalence of multipartite quantum states
NASA Astrophysics Data System (ADS)
Zhang, Tinggui; Zhao, Ming-Jing; Huang, Xiaofen
2016-10-01
We study the stochastic local operation and classical communication (SLOCC) equivalence for arbitrary dimensional multipartite quantum states. For multipartite pure states, we present a necessary and sufficient criterion in terms of their coefficient matrices. This condition can be used to classify some SLOCC equivalent quantum states with coefficient matrices having the same rank. For multipartite mixed state, we provide a necessary and sufficient condition by means of the realignment of matrix. Some detailed examples are given to identify the SLOCC equivalence of multipartite quantum states.
ERIC Educational Resources Information Center
McDougall, Dennis; Hawkins, Jacqueline; Brady, Michael; Jenkins, Amelia
2006-01-01
This article illustrates (a) 2 recent innovations in the changing criterion research design, (b) how these innovations apply to research and practice in special education, and (c) how clinical needs influence design features of the changing criterion design. The first innovation, the range-bound changing criterion, is a very simple variation of…
ERIC Educational Resources Information Center
Hambleton, Ronald K.; Simon, Robert A.
The subject of constructing criterion-referenced tests is often researched, but many technical problems remain to be satisfactorily resolved. Foremost, criterion-referenced test developers need a comprehensive set of steps for construction. In this paper, 14 logical steps for building criterion-referenced tests that refer to several different…
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
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.
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
2015-11-27
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.
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
Asymmetry in olfactory generalization and the inclusion criterion in ants.
Bos, Nick
2014-01-01
Animals constantly face the challenge of extracting important information out of their environment, and for many animals much of this information is chemical in nature. The ability to discriminate and generalize between chemical stimuli is extremely important and is commonly thought to depend mostly on the structural similarity between the different stimuli. However, we previously provided evidence that in the carpenter ant Camponotus aethiops, generalization not only depends on structural similarity, but also on the animal's previous training experience. When individual ants were conditioned to substance A, they generalized toward a mixture of A and B. However, when trained to substance B, they did not generalize toward this mixture, resulting in asymmetrical generalization. This asymmetry followed an inclusion criterion, where the ants consistently generalized from a molecule with a long carbon chain to molecules with a shorter chain, but not the other way around. Here I will review the evidence for the inclusion criterion, describe possible proximate mechanisms underlying this phenomenon as well as discuss its potential adaptive significance.
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.
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.
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.
Asymmetry in olfactory generalization and the inclusion criterion in ants.
Bos, Nick
2014-01-01
Animals constantly face the challenge of extracting important information out of their environment, and for many animals much of this information is chemical in nature. The ability to discriminate and generalize between chemical stimuli is extremely important and is commonly thought to depend mostly on the structural similarity between the different stimuli. However, we previously provided evidence that in the carpenter ant Camponotus aethiops, generalization not only depends on structural similarity, but also on the animal's previous training experience. When individual ants were conditioned to substance A, they generalized toward a mixture of A and B. However, when trained to substance B, they did not generalize toward this mixture, resulting in asymmetrical generalization. This asymmetry followed an inclusion criterion, where the ants consistently generalized from a molecule with a long carbon chain to molecules with a shorter chain, but not the other way around. Here I will review the evidence for the inclusion criterion, describe possible proximate mechanisms underlying this phenomenon as well as discuss its potential adaptive significance. PMID:25346797
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.
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.
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.
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.
Test of the Hill Stability Criterion against Chaos Indicators
NASA Astrophysics Data System (ADS)
Satyal, Suman; Quarles, Billy; Hinse, Tobias
2012-10-01
The efficacy of Hill Stability (HS) criterion is tested against other known chaos indicators such as Maximum Lyapunov Exponents (MLE) and Mean Exponential Growth of Nearby Orbits (MEGNO) maps. First, orbits of four observationally verified binary star systems: γ Cephei, Gliese-86, HD41004, and HD196885 are integrated using standard integration packages (MERCURY, SWIFTER, NBI, C/C++). The HS which measures orbital perturbation of a planet around the primary star due to the secondary star is calculated for each system. The LEs spectra are generated to measure the divergence/convergence rate of stable manifolds and the MEGNO maps are generated by using the variational equations of the system during the integration process. These maps allow to accurately differentiate between stable and unstable dynamical systems. Then the results obtained from the analysis of HS, MLE, and MEGNO maps are checked for their dynamical variations and resemblance. The HS of most of the planets seems to be stable, quasi-periodic for at least ten million years. The MLE and the MEGNO maps also indicate the local quasi-periodicity and global stability in relatively short integration period. The HS criterion is found to be a comparably efficient tool to measure the stability of planetary orbits.
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
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
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.
The diminishing criterion model for metacognitive regulation of time investment.
Ackerman, Rakefet
2014-06-01
According to the Discrepancy Reduction Model for metacognitive regulation, people invest time in cognitive tasks in a goal-driven manner until their metacognitive judgment, either judgment of learning (JOL) or confidence, meets their preset goal. This stopping rule should lead to judgments above the goal, regardless of invested time. However, in many tasks, time is negatively correlated with JOL and confidence, with low judgments after effortful processing. This pattern has often been explained as stemming from bottom-up fluency effects on the judgments. While accepting this explanation for simple tasks, like memorizing pairs of familiar words, the proposed Diminishing Criterion Model (DCM) challenges this explanation for complex tasks, like problem solving. Under the DCM, people indeed invest effort in a goal-driven manner. However, investing more time leads to increasing compromise on the goal, resulting in negative time-judgment correlations. Experiment 1 exposed that with word-pair memorization, negative correlations are found only with minimal fluency and difficulty variability, whereas in problem solving, they are found consistently. As predicted, manipulations of low incentives (Experiment 2) and time pressure (Experiment 3) in problem solving revealed greater compromise as more time was invested in a problem. Although intermediate confidence ratings rose during the solving process, the result was negative time-confidence correlations (Experiments 3, 4, and 5), and this was not eliminated by the opportunity to respond "don't know" (Experiments 4 and 5). The results suggest that negative time-judgment correlations in complex tasks stem from top-down regulatory processes with a criterion that diminishes with invested time.
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.
ICF Ignition, the Lawson Criterion, and Comparison with MFE Ignition
NASA Astrophysics Data System (ADS)
Betti, R.
2009-11-01
The Lawson criterion, which determines the onset of thermonuclear ignition, is usually expressed through the product pτ > 10 atm . s, where p is the plasma pressure in atm and τ is the energy confinement time in seconds. In magnetic fusion devices, both the pressure and confinement time are routinely measured and the performance of each discharge can be assessed by comparing the value of pτ with respect to the ignition value (10 atm . s). In inertial confinement fusion, both p and τ cannot be directly measured and the performance of surrogate and/or subignited ICF implosions cannot be assessed with respect to the ignition condition. This makes it difficult to compare the performance of ICF implosions with that of magnetic fusion energy (MFE) discharges. Here, we define the meaning of ignition in ICF implosions and compare it to MFE ignition. We then show that a multidimensional ignition condition for inertial confinement fusion can be cast in a form that depends on three measurable parameters of the compressed-fuel assembly: the hot-spot ion temperature T, the neutron yield normalized to the 1-D prediction (yield over clean or YOC) and the total areal density ρR, which includes the cold shell's contribution. A family of marginal-ignition curves are derived in the ρR--T plane.footnotetext C. D. Zhou and R. Betti, Phys. Plasmas 15, 102707 (2008). On this plane, hydrodynamic-equivalent curves show how a given implosion would perform with respect to the ignition condition when the laser-driver energy is varied. Such a criterion can be used to measure the ignition marginfootnotetext D. S. Clark, S. W. Haan, and J. D. Salmonson, Phys. Plasmas 15, 056305 (2008). of NIF targets and to predict the performance of OMEGA targets when scaled up to NIF energies. This work has been supported by the US Department of Energy under Cooperative Agreement Nos. DE-FC02-ER54789 and DE-FC52-08NA28302.
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 simple metal-insulator criterion for the doped Mott-Hubbard materials
NASA Astrophysics Data System (ADS)
Gavrichkov, Vladimir A.
2015-04-01
A simple metal-insulator criterion for doped Mott-Hubbard materials has been derived. Its readings are closely related to the orbital and spin nature of the ground states of the unit cell. The available criterion readings (metal or insulator) in the paramagnetic phase reveal the possibility of the insulator state of doped materials with the forbidden first removal electron states. According to its physical meaning, the result is similar to the Wilson's criterion in itinerant electron systems. The application of the criterion to high-Tc cuprates is discussed.
Centration-distortion error: a criterion of perceptual dysfunction.
Mecke, V
This was a study to determine whether centration, as a perceptual process, could be a criterion for differentiating between neurologically impaired and emotionally disturbed children. Centration was defined by Piaget as a prolonged involuntary attachment of a sensory modality to one part of a field, causing perceptual errors of exaggerations and distortions. It is hypothesized that centration would affect motor behavior, producing effects on drawing tasks characterized by separation of designs or their parts, coincident with distortions of the figures drawn. The neurologically impaired children were identified as having primary difficulties with perception whereas the emotionally disturbed children would have primary difficulties with intellection. The centration-distortion error would characterize the drawing of the neurologically impaired but not those of the emotionally disturbed children. A sample of 44 children was selected, each with EEG records, psychological tests and psychiatric interviews used as differential criteria for the groups. Eleven children were diagnosed as having minimal brain damage, 33 as emotionally disturbed. Three psychologists scored the Bender Gestalt tests, blind, for indicators of brain injury and emotional disturbance as defined by Koppitz' criteria, and for the centration-distortion error. The hypothesis was upheld at the .001 level of confidence, validating an earlier pilot study. PMID:4468761
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.
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.
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 three-scale cracking criterion for drying soils
NASA Astrophysics Data System (ADS)
Hueckel, Tomasz; Mielniczuk, Boleslaw; El Youssoufi, Moulay; Hu, Liang; Laloui, Lyesse
2014-10-01
Cracking is a most unwanted development in soil structures undergoing periodic drying and wetting. Desiccation cracks arise in an apparent absence of external forces. Hence, either an internal, self-equilibrated stress pattern resulting from kinematic incompatibilities, or a stress resulting from reaction forces at the constraints appear as a cracking cause, when reaching tensile strength. At a meso-scale, tubular drying pores are considered in the vicinity of a random imperfection, inducing a stress concentration in the presence of significant pore suction. This approach allows one to use the effective stress analysis, which otherwise, away from the stress concentration, usually yields compressive effective stress and hence a physically incompatible criterion for a tensile crack. Recent experiments on idealized configurations of clusters of grains provide geometrical data suggesting that an imperfection as a result of air entry deep into the granular medium penetrates over 4 to 8 internal radii of a typical pore could yield a tensile effective stress sufficient for crack propagation.
Centration-distortion error: a criterion of perceptual dysfunction.
Mecke, V
This was a study to determine whether centration, as a perceptual process, could be a criterion for differentiating between neurologically impaired and emotionally disturbed children. Centration was defined by Piaget as a prolonged involuntary attachment of a sensory modality to one part of a field, causing perceptual errors of exaggerations and distortions. It is hypothesized that centration would affect motor behavior, producing effects on drawing tasks characterized by separation of designs or their parts, coincident with distortions of the figures drawn. The neurologically impaired children were identified as having primary difficulties with perception whereas the emotionally disturbed children would have primary difficulties with intellection. The centration-distortion error would characterize the drawing of the neurologically impaired but not those of the emotionally disturbed children. A sample of 44 children was selected, each with EEG records, psychological tests and psychiatric interviews used as differential criteria for the groups. Eleven children were diagnosed as having minimal brain damage, 33 as emotionally disturbed. Three psychologists scored the Bender Gestalt tests, blind, for indicators of brain injury and emotional disturbance as defined by Koppitz' criteria, and for the centration-distortion error. The hypothesis was upheld at the .001 level of confidence, validating an earlier pilot study.
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.
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.
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 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.
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.
New Criterion and Tool for Caltrans Seismic Hazard Characterization
NASA Astrophysics Data System (ADS)
Shantz, T.; Merriam, M.; Turner, L.; Chiou, B.; Liu, X.
2008-12-01
Caltrans recently adopted new procedures for the development of response spectra for structure design. These procedures incorporate both deterministic and probabilistic criteria. The Next Generation Attenuation (NGA) models (2008) are used for deterministic assessment (using a revised late-Quaternary age fault database), and the USGS 2008 5% in 50-year hazard maps are used for probabilistic assessment. A minimum deterministic spectrum based on a M6.5 earthquake at 12 km is also included. These spectra are enveloped and the largest values used. A new publicly available web-based design tool for calculating the design spectrum will be used for calculations. The tool is built on a Windows-Apache-MySQL-PHP (WAMP) platform and integrates GoogleMaps for increased flexibility in the tool's use. Links to Caltrans data such as pre-construction logs of test borings assist in the estimation of Vs30 values used in the new procedures. Basin effects based on new models developed for the CFM, for the San Francisco Bay area by the USGS, and by Thurber (2008) are also incorporated. It is anticipated that additional layers such as CGS Seismic Hazard Zone maps will be added in the future. Application of the new criterion will result in expected higher levels of ground motion at many bridges west of the Coast Ranges. In eastern California, use of the NGA relationships for strike-slip faulting (the dominant sense of motion in California) will often result in slightly lower expected values for bridges. The expected result is a more realistic prediction of ground motions at bridges, in keeping with those motions developed for other large-scale and important structures. The tool is based on a simplified fault map of California, so it will not be used for more detailed evaluations such as surface rupture determination. Announcements regarding tool availability (expected to be in early 2009) are at http://www.dot.ca.gov/research/index.htm
Criterion-based (proficiency) training to improve surgical performance.
Fried, Marvin P; Kaye, Rachel J; Gibber, Marc J; Jackman, Alexis H; Paskhover, Boris P; Sadoughi, Babak; Schiff, Bradley; Fraioli, Rebecca E; Jacobs, Joseph B
2012-11-01
OBJECTIVE To investigate whether training otorhinolaryngology residents to criterion performance levels (proficiency) on the Endoscopic Sinus Surgery Simulator produces individuals whose performance in the operating room is at least equal to those who are trained by performing a fixed number of surgical procedures. DESIGN Prospective cohort. SETTING Two academic medical centers in New York City. PARTICIPANTS Otorhinolaryngology junior residents composed of 8 experimental subjects and 6 control subjects and 6 attending surgeons. INTERVENTION Experimental subjects achieved benchmark proficiency criteria on the Endoscopic Sinus Surgery Simulator; control subjects repeated the surgical procedure twice. MAIN OUTCOME MEASURES Residents completed validated objective tests to assess baseline abilities. All subjects were videotaped performing an initial standardized surgical procedure. Residents were videotaped performing a final surgery. Videotapes were assessed for metrics by an expert panel. RESULTS Attendings outperformed the residents in most parameters on the initial procedure. Experimental and attending groups outperformed controls in some parameters on the final procedure. There was no difference between resident groups in initial performance, but the experimental subjects outperformed the control subjects in navigation in the final procedure. Most important, there was no difference in final performance between subgroups of the experimental group on the basis of the number of trials needed to attain proficiency. CONCLUSIONS Simulator training can improve resident technical skills so that each individual attains a proficiency level, despite the existence of an intrinsic range of abilities. This proficiency level translates to at least equal, if not superior, operative performance compared with that of current conventional training with finite repetition of live surgical procedures.
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.
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Federal Register 2010, 2011, 2012, 2013, 2014
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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.
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…
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…
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…
ERIC Educational Resources Information Center
Heffernan, Neil; Otoshi, Junko
2015-01-01
This paper reports on a classroom-based inquiry using quantitative methods conducted with Japanese EFL students' writing practice using ETS's Criterion. The purpose of the study is to examine the actual effects of teachers' feedback on students' writing on Criterion. Twelve university students in Japan participated in this study, while completing…
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…
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…
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.
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…
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…
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…
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.
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…
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…
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.
Toward a unified theory of decision criterion learning in perceptual categorization.
Maddox, W Todd
2002-11-01
Optimal decision criterion placement maximizes expected reward and requires sensitivity to the category base rates (prior probabilities) and payoffs (costs and benefits of incorrect and correct responding). When base rates are unequal, human decision criterion is nearly optimal, but when payoffs are unequal, suboptimal decision criterion placement is observed, even when the optimal decision criterion is identical in both cases. A series of studies are reviewed that examine the generality of this finding, and a unified theory of decision criterion learning is described (Maddox & Dodd, 2001). The theory assumes that two critical mechanisms operate in decision criterion learning. One mechanism involves competition between reward and accuracy maximization: The observer attempts to maximize reward, as instructed, but also places some importance on accuracy maximization. The second mechanism involves a flat-maxima hypothesis that assumes that the observer's estimate of the reward-maximizing decision criterion is determined from the steepness of the objective reward function that relates expected reward to decision criterion placement. Experiments used to develop and test the theory require each observer to complete a large number of trials and to participate in all conditions of the experiment. This provides maximal control over the reinforcement history of the observer and allows a focus on individual behavioral profiles. The theory is applied to decision criterion learning problems that examine category discriminability, payoff matrix multiplication and addition effects, the optimal classifier's independence assumption, and different types of trial-by-trial feedback. In every case the theory provides a good account of the data, and, most important, provides useful insights into the psychological processes involved in decision criterion learning.
A Seventh Criterion for the Identification of Bacterial Magnetofossils
NASA Astrophysics Data System (ADS)
Kirschvink, J. L.
2001-05-01
break down into magnetic 'flower' structures as they approach the single-domain to two-domain transition (Fabian et al., GJI 124: 89-104; Newell & Merrill JGR 105: 19377-19391), with the greatest warping around the sharp corners. In this situation, the bacteria would gain a higher net magnetic moment per Fe atom by building a new crystal along the chain rather than fleshing out the corners in the existing particles. If confirmed by suitable numerical calculations on elongate hexagonal magnetite prisms, this morphology could provide a seventh criterion for the Identification of bacterial magnetofossils in the ALH84001 meteorite.
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; Frazier, Patricia; Frankfurt, Sheila
2010-01-01
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
Efficiency of event-based sampling according to error energy criterion.
Miskowicz, Marek
2010-01-01
The paper belongs to the studies that deal with the effectiveness of the particular event-based sampling scheme compared to the conventional periodic sampling as a reference. In the present study, the event-based sampling according to a constant energy of sampling error is analyzed. This criterion is suitable for applications where the energy of sampling error should be bounded (i.e., in building automation, or in greenhouse climate monitoring and control). Compared to the integral sampling criteria, the error energy criterion gives more weight to extreme sampling error values. The proposed sampling principle extends a range of event-based sampling schemes and makes the choice of particular sampling criterion more flexible to application requirements. In the paper, it is proved analytically that the proposed event-based sampling criterion is more effective than the periodic sampling by a factor defined by the ratio of the maximum to the mean of the cubic root of the signal time-derivative square in the analyzed time interval. Furthermore, it is shown that the sampling according to energy criterion is less effective than the send-on-delta scheme but more effective than the sampling according to integral criterion. On the other hand, it is indicated that higher effectiveness in sampling according to the selected event-based criterion is obtained at the cost of increasing the total sampling error defined as the sum of errors for all the samples taken.
Efficiency of Event-Based Sampling According to Error Energy Criterion
Miskowicz, Marek
2010-01-01
The paper belongs to the studies that deal with the effectiveness of the particular event-based sampling scheme compared to the conventional periodic sampling as a reference. In the present study, the event-based sampling according to a constant energy of sampling error is analyzed. This criterion is suitable for applications where the energy of sampling error should be bounded (i.e., in building automation, or in greenhouse climate monitoring and control). Compared to the integral sampling criteria, the error energy criterion gives more weight to extreme sampling error values. The proposed sampling principle extends a range of event-based sampling schemes and makes the choice of particular sampling criterion more flexible to application requirements. In the paper, it is proved analytically that the proposed event-based sampling criterion is more effective than the periodic sampling by a factor defined by the ratio of the maximum to the mean of the cubic root of the signal time-derivative square in the analyzed time interval. Furthermore, it is shown that the sampling according to energy criterion is less effective than the send-on-delta scheme but more effective than the sampling according to integral criterion. On the other hand, it is indicated that higher effectiveness in sampling according to the selected event-based criterion is obtained at the cost of increasing the total sampling error defined as the sum of errors for all the samples taken. PMID:22294925
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
Coefficient of Performance at Maximum χ-Criterion for Feynman Ratchet as a Refrigerator
NASA Astrophysics Data System (ADS)
Sheng, Shi-Qi; Yang, Pan; Tu, Zhan-Chun
2014-10-01
The χ-criterion is defined as the product of the energy conversion efficiency and the heat absorbed per unit time by the working substance [de Tomás et al., Phys. Rev. E 85 (2012) 010104(R)]. The χ-criterion for Feynman ratchet as a refrigerator operating between two heat baths is optimized. Asymptotic solutions of the coefficient of performance at maximum χ-criterion for Feynman ratchet are investigated at both large and small temperature difference. An interpolation formula, which fits the numerical solution very well, is proposed. Besides, the sufficient condition for the universality of the coefficient of performance at maximum χ is investigated.
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. PMID:27433534
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.
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.
A Consistent Information Criterion for Support Vector Machines in Diverging Model Spaces
Zhang, Xiang; Wu, Yichao; Wang, Lan; Li, Runze
2015-01-01
Information criteria have been popularly used in model selection and proved to possess nice theoretical properties. For classification, Claeskens et al. (2008) proposed support vector machine information criterion for feature selection and provided encouraging numerical evidence. Yet no theoretical justification was given there. This work aims to fill the gap and to provide some theoretical justifications for support vector machine information criterion in both fixed and diverging model spaces. We first derive a uniform convergence rate for the support vector machine solution and then show that a modification of the support vector machine information criterion achieves model selection consistency even when the number of features diverges at an exponential rate of the sample size. This consistency result can be further applied to selecting the optimal tuning parameter for various penalized support vector machine methods. Finite-sample performance of the proposed information criterion is investigated using Monte Carlo studies and one real-world gene selection problem. PMID:27239164
Analysis of a delayed fracture criterion for lifetime prediction of viscoelastic polymer materials
NASA Astrophysics Data System (ADS)
Guedes, Rui Miranda
2012-08-01
In this work a multi-axial yield/failure model for viscoelastic/plastic materials is applied, which was developed by Naghdi and Murch (in J. Appl. Mech. 30:321-328, 1963) and later extended and refined by Crochet (in J. Appl. Mech. 33:327-334, 1966), to predict long-term creep rupture of polymers. The criterion defines a function, which depends on time, the viscoelastic properties and applied stress, to establish an empirical law with creep yield (fracture). In this work a linear relationship is proposed, defined as a time-dependent failure criterion, which can be applied for extrapolation purposes. A comparative analysis using energy-based failure criteria is performed. It is proved, for the polymers considered in this study, that the proposed time-dependent failure criterion holds for long times. Experimental data are used to illustrate the applicability of this time-dependent failure criterion.
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.
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.
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.
NASA Astrophysics Data System (ADS)
Yukhno, L. F.
2008-12-01
For an overdetermined system of linear algebraic equations, systems obtained by introducing independent random errors into the original right-hand side are examined. Under certain assumptions on how these random variables are distributed, a practical stopping criterion is proposed for an iterative process that minimizes the sum of the squares of the residuals for the above systems. Numerical results demonstrating the efficiency of this criterion for some ill-conditioned problems are presented.
Kattnig, Alain P; Primot, Jérôme
2008-03-31
Imaging systems comparisons remains today a sensitive subject because of the difficulty to merge radiometric and spatial dimensions into a single, easy to use, parameter. By leaning explicitly on professional image users and their requirements we show how to build such a criterion, called Mission-Quality. A specific observation campaign is described and its results are used to calibrate and carry first proof of the criterion adequacy.
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.
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.
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
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
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
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.
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
Analytical investigation of an isomerization system using the resonance overlap criterion
NASA Astrophysics Data System (ADS)
Fukuda, Hiroya; Petrosky, Tomio; Konishi, Tetsuro
2016-09-01
An analytical procedure to obtain the volume of reactive initial condition in the reactant well is described. The applicability of the well-known Chirikov resonance overlap criterion is tested to determine the boundary between the reactive and unreactive regions of phase space in the reactant well for a classical Hamiltonian system with symmetric double-well potential coupled with a harmonic oscillator. As usual, the system is reduced to the two-dimensional whisker mapping in order to apply the overlap criterion. For the calculation process, the applicability of the overlap criterion is examined in cases where up to period-n (n=1,2,3) resonances are included in the criterion. Theoretical results are compared to numerical simulation through the Davis-Gray unimolecular reaction rate constant. It is found that Chirikov's criterion led to a bad estimation for lower periods up to n=2, but produced a reliable estimation after taking into account higher periods with n=3. However, there are some situations where the agreement including n=3 is still not good. The reasons for this disagreement and the possibilities for improvement of the calculation accuracy are discussed.
Cooper, Rachel V
2013-11-01
False positives arise when people without disorders are diagnosed as having disorders. Various approaches for avoiding false positives have been suggested. This review critically assesses the roles of zones of rarity, the threshold problem (the problem of determining the boundary of disorder in cases that shade into normality), and the Diagnostic and Statistical Manual of Mental Disorders (DSM) criterion that requires that a disorder cause clinically significant impairment or distress (the harm criterion). The lack of zones of rarity in much of psychiatry gives rise to the threshold problem. The DSM harm criterion is frequently presented as offering a solution to the threshold problem. However, I argue that the harm criterion cannot offer a general solution to the threshold problem, as harm is not always correlated with the intensity and frequency of symptoms. Still, the harm criterion is essential to ensure that people who are merely different are not diagnosed as having a disorder. The threshold problem can be addressed by selecting symptom-based cut-off points to distinguish between disorder and normality. These cut-off points are frequently arbitrary in the sense that they often reflect no natural division between disorder and normal, but they may be more or less wisely chosen. Where possible, the thresholds should be set so that the advantages of diagnosis can be expected to outweigh the disadvantages.
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.
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.
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.
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)
Saboori, M.; Gholipour, J.; Champliaud, H.; Gakwaya, A.; Savoie, J.; Wanjara, P.
2011-05-01
One of the failure modes in tube hydroforming (THF) is bursting. To predict the burst pressure in the THF process, Brozzo's decoupled ductile fracture criterion was used in conjunction with a dynamic nonlinear commercial finite element software, Ls-Dyna, and the criterion was evaluated using the data obtained from the free expansion (tube bulging) tests performed on 0.9 mm and 1.2 mm thick stainless steel (SS) 321 tubes. The predicted burst pressures were compared with the experimental results for both thicknesses. The predicted burst failure of the tube bulging, based on the Brozzo's criterion, demonstrated a good agreement with the experimental data, indicating that the present approach for predicting the burst failure for the tube bulging can be extended to predict formability limits in THF applications.
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.
Evaluation of a site-specific criterion using outdoor experimental streams
Hedtke, S.F.; Arthur, J.W.
1985-02-01
An overview of a study to evaluate a site-specific water quality criteria for pentachlorophenol (PCP) in outdoor experimental streams is presented. The site-specific criterion was calculated from acute toxicity results for eight resident species and the relationship between acute and chronic toxicity of PCP. The PCP concentration expected to protect aquatic life (30-day average criterion concentration) was less than or equal to 48 micrograms/l. Outdoor experimental streams were subsequently dosed continuously for 84 days at 48, 144, and 432 micrograms PCP/l. Measurements of the biological structure and ecosystem processes within the exposure streams were compared to a control system. Effects on snails were found only at 432 micrograms/l, but effects on fish, periphyton, and system metabolism were found at 432, 144, and 48 micrograms/l. The small differences between the criterion-dosed stream (48 micrograms/l) and the control stream may have been caused by PCP or interstream variation.
A new criterion for failure of materials by environment-induced cracking
NASA Technical Reports Server (NTRS)
Williams, D. P.
1973-01-01
A new criterion has been developed for predicting failure of materials by environment-induced cracking. The criterion has been developed by the use of fracture mechanics concepts and assumes that the relationship between crack-growth rate and stress intensity can be described by three separable regions of behavior as first suggested by Wiederhorn. The analytical form of the criterion relates failure time to the initial crack length and the critical crack length or alternatively, to the initial stress intensity and the fracture toughness for various conditions of stress and the environmental variables. The analytical expression is examined by the use of some experimental data on the hydrogen-induced cracking of Ti-5Al-2.5 Sn, and it is demonstrated that the expression predicts the general expected form of the relationship between the normalized stress intensity parameter and the failure time.
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.
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
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.
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.
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.
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.
A line-of-sight performance criterion for controller design of a proposed laboratory model
NASA Technical Reports Server (NTRS)
Lim, Kyong B.; Horta, Lucas G.
1990-01-01
A line-of-sight performance criterion is derived for a proposed Controls Structures Interaction model, and its many uses in the control design process for fine pointing control are illustrated. A linearized line-of-sight (LOS) criterion is used for direct controller design and as a performance measure to judge different control methodologies. Numerical simulation results are shown where the three approaches: linear quadratic Gaussian theory, robust eigensystem assignment, and local velocity feedback are used for vibration control. Results indicate that the linear quadratic Gaussian controller, which incorporates a linearized LOS weighting matrix directly, yields good performance without wasting energy to control motions that have no influence on the LOS.
A failure criterion for laminates governed by free edge interlaminar shear stress
NASA Astrophysics Data System (ADS)
Joo, J. W.; Sun, C. T.
1992-01-01
Interlaminar shear stresses in balanced and symmetric laminates with free edges and failure due to these stresses were studied. It was shown that the average interlaminar shear stress near the free edge is linearly related to the mismatch of the extension-shear coupling of the top and bottom sublaminates separated by the interface of interest. A simple failure criterion based on the mismatch of the extension shear coupling was introduced to predict laminate failure stress and strain. The validity of this criterion was verified by experiments using AS4/3501-6 graphite/epoxy composite laminates.
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.
The Ultimate Resolution Criterion For Out-Of-The-Cockpit Visual Scene Generation In Real Time
NASA Astrophysics Data System (ADS)
Setty, K. S. L.
1980-12-01
Visual system resolution is the first important criterion mentioned in a functional specification for the real time dynamic simulation of any visual system. This criterion has a profound effect on the estimation of the cost and the complexity of any dynamic visual system design of very wide field of view. What is essential in terms of static and dynamic resolution of the simulated visual system for proper pilot training in tactical combat missions is described in this paper, around a spectrum of highly relevant conjectures such as the physical limit of computer processing, innovations in digital image processing, and the speed of perception in visual information processing by the human brain.
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.
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…
ERIC Educational Resources Information Center
Morgan, George
This study developed a two-parameter linear probabilistic model of criterion referenced measurement, which relates an examinee's observed ability to his true ability through a guessing parameter and a carelessness parameter, both of which are probabilities. This model was applied to a survey of 10- and 14-year-old Australian students to estimate…
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…
Decision Reliability and Classification Validity for Decision Oriented Criterion-Referenced Tests.
ERIC Educational Resources Information Center
Faggen, Jane
Formulas are presented for decision reliability and for classification validity for mastery/nonmastery decisions based on criterion referenced tests. Two item parameters are used: the probability of a master answering an item correctly, and the probability of a nonmaster answering an item incorrectly. The theory explores the relationships of…
Procedures and Issues in the Validation of Criterion-Referenced Tests.
ERIC Educational Resources Information Center
Klein, Stephen P.; Kosecoff, Jacqueline P.
Four common uses for criterion-referenced tests (CRT) are outlined: describing student achievement, improving curriculum development, being sensitive indicators of the effects of instruction, and facilitating classroom management decisions. These uses parallel various forms of empirically establishing the content, concurrent, and predictive…
Learning Patterns as Criterion for Forming Work Groups in 3D Simulation Learning Environments
ERIC Educational Resources Information Center
Maria Cela-Ranilla, Jose; Molías, Luis Marqués; Cervera, Mercè Gisbert
2016-01-01
This study analyzes the relationship between the use of learning patterns as a grouping criterion to develop learning activities in the 3D simulation environment at University. Participants included 72 Spanish students from the Education and Marketing disciplines. Descriptive statistics and non-parametric tests were conducted. The process was…
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…
Using Criterion-Referenced Performance Indicators To Measure On-the-Job Performance of Graduates.
ERIC Educational Resources Information Center
Monson, Kyle C.
This study from the Community College of the Air Force (CCAF) evaluates the effectiveness of occupationally-related degree programs by using criterion-referenced performance indicators to measure the on-the-job performance of graduates. This study is designed to answer the question of whether there is a relationship between educational attainment…
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…
Food and Nutrition (Advanced). 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 Advanced 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 teachers…
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…
Child Development, Care and Guidance. 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 Child Development, Care and Guidance 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…
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…
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,…
10 CFR 840.5 - Criterion II-Substantial damages to persons offsite or property offsite.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 10 Energy 4 2013-01-01 2013-01-01 false Criterion II-Substantial damages to persons offsite or property offsite. 840.5 Section 840.5 Energy DEPARTMENT OF ENERGY EXTRAORDINARY NUCLEAR OCCURRENCES § 840.5... nuclear, or byproduct material; or (2) DOE finds that $2,500,000 or more of damage offsite has been...
10 CFR 840.5 - Criterion II-Substantial damages to persons offsite or property offsite.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 10 Energy 4 2012-01-01 2012-01-01 false Criterion II-Substantial damages to persons offsite or property offsite. 840.5 Section 840.5 Energy DEPARTMENT OF ENERGY EXTRAORDINARY NUCLEAR OCCURRENCES § 840.5... nuclear, or byproduct material; or (2) DOE finds that $2,500,000 or more of damage offsite has been...
10 CFR 840.5 - Criterion II-Substantial damages to persons offsite or property offsite.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 10 Energy 4 2011-01-01 2011-01-01 false Criterion II-Substantial damages to persons offsite or property offsite. 840.5 Section 840.5 Energy DEPARTMENT OF ENERGY EXTRAORDINARY NUCLEAR OCCURRENCES § 840.5... nuclear, or byproduct material; or (2) DOE finds that $2,500,000 or more of damage offsite has been...
10 CFR 840.5 - Criterion II-Substantial damages to persons offsite or property offsite.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 10 Energy 4 2010-01-01 2010-01-01 false Criterion II-Substantial damages to persons offsite or property offsite. 840.5 Section 840.5 Energy DEPARTMENT OF ENERGY EXTRAORDINARY NUCLEAR OCCURRENCES § 840.5... nuclear, or byproduct material; or (2) DOE finds that $2,500,000 or more of damage offsite has been...
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—...
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…
ERIC Educational Resources Information Center
Duval County School Board, Jacksonville, FL.
Several intermediate performance objectives and corresponding criterion measures are listed for each of three terminal objectives for an exploration of home furnishing, equipment, and services occupations course for eighth and ninth grade students. The materials were developed for a 12- to 18-week course designed to provide exploration…
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.
Using the EMD method to determine fault criterion for medium-low pressure gas regulators
NASA Astrophysics Data System (ADS)
Hao, Xuejun; Liu, Qiang; Yang, Guobin; Du, Yi
2015-11-01
By extracting the outlet pressure data of gas regulators, this paper uses the EMD toolbox of the MATLAB software, which can perform data decomposition and the Hilbert-Huang Transform to find the rules with fault data. Eventually, the medium-low pressure gas regulator fault criterion can be established.
Predicting ethnic and racial discrimination: a meta-analysis of IAT criterion studies.
Oswald, Frederick L; Mitchell, Gregory; Blanton, Hart; Jaccard, James; Tetlock, Philip E
2013-08-01
This article reports a meta-analysis of studies examining the predictive validity of the Implicit Association Test (IAT) and explicit measures of bias for a wide range of criterion measures of discrimination. The meta-analysis estimates the heterogeneity of effects within and across 2 domains of intergroup bias (interracial and interethnic), 6 criterion categories (interpersonal behavior, person perception, policy preference, microbehavior, response time, and brain activity), 2 versions of the IAT (stereotype and attitude IATs), 3 strategies for measuring explicit bias (feeling thermometers, multi-item explicit measures such as the Modern Racism Scale, and ad hoc measures of intergroup attitudes and stereotypes), and 4 criterion-scoring methods (computed majority-minority difference scores, relative majority-minority ratings, minority-only ratings, and majority-only ratings). IATs were poor predictors of every criterion category other than brain activity, and the IATs performed no better than simple explicit measures. These results have important implications for the construct validity of IATs, for competing theories of prejudice and attitude-behavior relations, and for measuring and modeling prejudice and discrimination.
Nonsuicidal self-injury disorder: Does Criterion B add diagnostic utility?
Brausch, Amy M; Muehlenkamp, Jennifer J; Washburn, Jason J
2016-10-30
The current paper evaluates Criterion B for Non-Suicidal Self-Injury Disorder, which states that non-suicidal self-injury (NSSI) must occur for at least one function. The majority of individuals who engage in NSSI report at least one function, so it is unclear if Criterion B provides diagnostic utility in individuals who already meet Criterion A (i.e., NSSI occurring on 5 or more days in the past 12 months). This paper compared individuals meeting Criterion A (threshold group) to those with 1-4 acts of NSSI in the past year (subthreshold group) in two different samples. The first sample included 217 undergraduate students, and the second sample included 1082 individuals from a behavioral health hospital, all with past-year NSSI. The majority of both samples reported at least one function of NSSI (99%). For the undergraduate sample, the number of and level of endorsement of functions were similar across threshold and subthreshold groups. For the behavioral health sample, the threshold group endorsed significantly more functions for NSSI and greater endorsement of affect regulation, self-punishment, and toughness compared to the subthreshold group. While some differences were found between NSSI groups, overall endorsement of functions for NSSI appears to be a universal characteristic regardless of NSSI frequency.
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
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,…
ERIC Educational Resources Information Center
Bozdogan, Hamparsum
1987-01-01
This paper studies the general theory of Akaike's Information Criterion (AIC) and provides two analytical extensions. The extensions make AIC asymptotically consistent and penalize overparameterization more stringently to pick only the simplest of the two models. The criteria are applied in two Monte Carlo experiments. (Author/GDC)
10 CFR 840.5 - Criterion II-Substantial damages to persons offsite or property offsite.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 10 Energy 4 2014-01-01 2014-01-01 false Criterion II-Substantial damages to persons offsite or property offsite. 840.5 Section 840.5 Energy DEPARTMENT OF ENERGY EXTRAORDINARY NUCLEAR OCCURRENCES § 840.5... nuclear, or byproduct material; or (2) DOE finds that $2,500,000 or more of damage offsite has been...
Predicting ethnic and racial discrimination: a meta-analysis of IAT criterion studies.
Oswald, Frederick L; Mitchell, Gregory; Blanton, Hart; Jaccard, James; Tetlock, Philip E
2013-08-01
This article reports a meta-analysis of studies examining the predictive validity of the Implicit Association Test (IAT) and explicit measures of bias for a wide range of criterion measures of discrimination. The meta-analysis estimates the heterogeneity of effects within and across 2 domains of intergroup bias (interracial and interethnic), 6 criterion categories (interpersonal behavior, person perception, policy preference, microbehavior, response time, and brain activity), 2 versions of the IAT (stereotype and attitude IATs), 3 strategies for measuring explicit bias (feeling thermometers, multi-item explicit measures such as the Modern Racism Scale, and ad hoc measures of intergroup attitudes and stereotypes), and 4 criterion-scoring methods (computed majority-minority difference scores, relative majority-minority ratings, minority-only ratings, and majority-only ratings). IATs were poor predictors of every criterion category other than brain activity, and the IATs performed no better than simple explicit measures. These results have important implications for the construct validity of IATs, for competing theories of prejudice and attitude-behavior relations, and for measuring and modeling prejudice and discrimination. PMID:23773046
Developing District Made Criterion Referenced Tests: A Standard of Excellence for Effective Schools.
ERIC Educational Resources Information Center
Conyers, John G.; And Others
Research on the lack of correlation between standardized tests and school district goals has suggested that district goals might be better met by supplementing standardized tests with district-made criterion-referenced testing systems. This article reports on the development of such a system, the Academic Learning Progress Assessment System…
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…
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.…
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;…
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,…
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.
16 CFR 1631.34 - Small carpets and rugs not meeting acceptance criterion.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Small carpets and rugs not meeting... FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE SURFACE FLAMMABILITY OF SMALL CARPETS AND RUGS (FF 2-70) Rules and Regulations § 1631.34 Small carpets and rugs not meeting acceptance criterion. (a) If...
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... FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE SURFACE FLAMMABILITY OF SMALL CARPETS AND RUGS (FF 2-70) Rules and Regulations § 1631.34 Small carpets and rugs not meeting acceptance criterion. (a) If...
16 CFR 1631.34 - Small carpets and rugs not meeting acceptance criterion.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Small carpets and rugs not meeting... FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE SURFACE FLAMMABILITY OF SMALL CARPETS AND RUGS (FF 2-70) Rules and Regulations § 1631.34 Small carpets and rugs not meeting acceptance criterion. (a) If...
16 CFR 1631.34 - Small carpets and rugs not meeting acceptance criterion.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Small carpets and rugs not meeting... FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE SURFACE FLAMMABILITY OF SMALL CARPETS AND RUGS (FF 2-70) Rules and Regulations § 1631.34 Small carpets and rugs not meeting acceptance criterion. (a) If...
16 CFR 1631.34 - Small carpets and rugs not meeting acceptance criterion.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Small carpets and rugs not meeting... FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE SURFACE FLAMMABILITY OF SMALL CARPETS AND RUGS (FF 2-70) Rules and Regulations § 1631.34 Small carpets and rugs not meeting acceptance criterion. (a) If...
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…
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…
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…
Nonsuicidal self-injury disorder: Does Criterion B add diagnostic utility?
Brausch, Amy M; Muehlenkamp, Jennifer J; Washburn, Jason J
2016-10-30
The current paper evaluates Criterion B for Non-Suicidal Self-Injury Disorder, which states that non-suicidal self-injury (NSSI) must occur for at least one function. The majority of individuals who engage in NSSI report at least one function, so it is unclear if Criterion B provides diagnostic utility in individuals who already meet Criterion A (i.e., NSSI occurring on 5 or more days in the past 12 months). This paper compared individuals meeting Criterion A (threshold group) to those with 1-4 acts of NSSI in the past year (subthreshold group) in two different samples. The first sample included 217 undergraduate students, and the second sample included 1082 individuals from a behavioral health hospital, all with past-year NSSI. The majority of both samples reported at least one function of NSSI (99%). For the undergraduate sample, the number of and level of endorsement of functions were similar across threshold and subthreshold groups. For the behavioral health sample, the threshold group endorsed significantly more functions for NSSI and greater endorsement of affect regulation, self-punishment, and toughness compared to the subthreshold group. While some differences were found between NSSI groups, overall endorsement of functions for NSSI appears to be a universal characteristic regardless of NSSI frequency. PMID:27479110
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
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…
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)
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.
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…
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…
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…
46 CFR 170.173 - Criterion for vessels of unusual proportion and form.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 46 Shipping 7 2010-10-01 2010-10-01 false Criterion for vessels of unusual proportion and form. 170.173 Section 170.173 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS Weather Criteria § 170.173...
A comparison between criterion functions for linear classifiers, with an application to neural nets
Barnard, E.; Casasent, D. )
1989-09-01
A variety of criterion functions (or scalar performance measures) have been suggested for the design of nonparametric linear classifiers. The classification performance of the most important of these on a typical two-class problem are investigated. The results of the investigation are then applied to the analysis and synthesis of neural-net classifiers.classifiers.
The Spirit Is Willing, but the Flesh Is Weak: Criterion-Referenced Testing in Wyoming.
ERIC Educational Resources Information Center
Moore, Alan D.; Cross, Tracy L.
The perceived needs of public school personnel in Wyoming with respect to the development and use of criterion-referenced tests (CRTs) as part of a district-wide testing program were assessed using a survey designed for the study. Questionnaires were sent to all superintendents, assistant superintendents, and curriculum directors in the state. Of…
NASA Astrophysics Data System (ADS)
Keen, K. M.
1985-06-01
Larger corner reflector ground targets currently planned for spaceborne SAR calibration will require planar A-sandwich radome covers for weather protection and mechanical stability. The radomes must be inclined with respect to reflector apertures, however, to avoid scattering cross-section uncertainties in the target beam peak direction. A criterion for inclination angle is derived here.
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
Hirschi, Andreas
2009-01-01
Interest differentiation and elevation are supposed to provide important information about a person's state of interest development, yet little is known about their development and criterion validity. The present study explored these constructs among a group of Swiss adolescents. Study 1 applied a cross-sectional design with 210 students in 11th…
A Defensible Model for Determining a Minimal Cut-Off Score for Criterion Referenced Tests.
ERIC Educational Resources Information Center
Bernknopf, Stan; And Others
The effectiveness of a model for determining a minimal cut-off score for criterion-referenced tests was examined. The model, based upon techniques presented originally by Nedelsky and by Angoff, was first used in conjunction with a multiple choice test developed for use in certifying school counselors in Georgia. A "knowledge estimation panel" was…
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…
Experimental study of the Ioffe-Regel criterion for amorphous indium oxide films
NASA Astrophysics Data System (ADS)
Graham, Mark R.; Adkins, C. J.; Behar, Haim; Rosenbaum, Ralph
1998-02-01
The Ioffe-Regel criterion predicts the existence of a metal-insulator transition in a film series when the parameter 0953-8984/10/4/010/img7 satisfies the criterion 0953-8984/10/4/010/img8 here 0953-8984/10/4/010/img9 is the Fermi wavenumber and 0953-8984/10/4/010/img10 is the elastic mean free path of the carriers. According to this criterion, films having 0953-8984/10/4/010/img11 are metallic, while films having 0953-8984/10/4/010/img12 are insulating. We experimentally observe the metal-insulator transition in amorphous indium oxide films at 0953-8984/10/4/010/img13. The values of 0953-8984/10/4/010/img7 were calculated from room temperature resistivity and Hall voltage measurements, while the metal-insulator transition was determined from low-temperature resistivity data using the `w'-criterion of Mobius and of Zabrodskii and Zinov'eva.
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…
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…
Laboratory Investigation on Shear Behavior of Rock Joints and a New Peak Shear Strength Criterion
NASA Astrophysics Data System (ADS)
Zhang, Xiaobo; Jiang, Qinghui; Chen, Na; Wei, Wei; Feng, Xixia
2016-09-01
In this study, shear tests on artificial rock joints with different roughness were conducted under five normal stress levels. Test results showed that the shear strength of rock joints had a positive correlation with roughness and the applied normal stress. Observation of joint specimens after shear tests indicated that asperity damage was mainly located in the steep areas facing the shear direction. The damaged joint surfaces tend to be rough, which implies that tensile failure plays an important role in shear behavior. As a result of the anisotropic characteristic of joint roughness, two quantitative 2D roughness parameters, i.e., the revised root-mean-square of asperity angle tan-1( Z 2r) and the maximum contact coefficient C m, were proposed considering the shear direction. The proposed roughness parameters can capture the difference of roughness in forward and reverse directions along a single joint profile. The normalized tensile strength and the proposed roughness parameters were used to perform a rational derivation of peak dilatancy angle. A negative exponential-type function was found to be appropriate to model the peak dilatancy angle. Using the new model of peak dilatancy angle, we obtained a new criterion for peak shear strength of rock joints. The good agreement between test results and predicted results by the new criterion indicated that the proposed criterion is capable of estimating the peak shear strength of rock joints. Comparisons between the new criterion and published models from available literature revealed that the proposed criterion has a good accuracy for predicting the peak shear strength of joints investigated in this study.
Lemly, A Dennis; Skorupa, Joseph P
2007-10-01
The US Environmental Protection Agency is developing a national water quality criterion for selenium that is based on concentrations of the element in fish tissue. Although this approach offers advantages over the current water-based regulations, it also presents new challenges with respect to implementation. A comprehensive protocol that answers the "what, where, and when" is essential with the new tissue-based approach in order to ensure proper acquisition of data that apply to the criterion. Dischargers will need to understand selenium transport, cycling, and bioaccumulation in order to effectively monitor for the criterion and, if necessary, develop site-specific standards. This paper discusses 11 key issues that affect the implementation of a tissue-based criterion, ranging from the selection of fish species to the importance of hydrological units in the sampling design. It also outlines a strategy that incorporates both water column and tissue-based approaches. A national generic safety-net water criterion could be combined with a fish tissue-based criterion for site-specific implementation. For the majority of waters nationwide, National Pollution Discharge Elimination System permitting and other activities associated with the Clean Water Act could continue without the increased expense of sampling and interpreting biological materials. Dischargers would do biotic sampling intermittently (not a routine monitoring burden) on fish tissue relative to the fish tissue criterion. Only when the fish tissue criterion is exceeded would a full site-specific analysis including development of intermedia translation factors be necessary. PMID:18046804
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…
Code of Federal Regulations, 2011 CFR
2011-01-01
... 10 Energy 4 2011-01-01 2011-01-01 false Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite. 840.4 Section 840.4 Energy DEPARTMENT OF ENERGY EXTRAORDINARY NUCLEAR OCCURRENCES § 840.4 Criterion I—Substantial discharge of radioactive material...
Code of Federal Regulations, 2010 CFR
2010-01-01
... 10 Energy 4 2010-01-01 2010-01-01 false Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite. 840.4 Section 840.4 Energy DEPARTMENT OF ENERGY EXTRAORDINARY NUCLEAR OCCURRENCES § 840.4 Criterion I—Substantial discharge of radioactive material...
Code of Federal Regulations, 2012 CFR
2012-01-01
... 10 Energy 4 2012-01-01 2012-01-01 false Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite. 840.4 Section 840.4 Energy DEPARTMENT OF ENERGY EXTRAORDINARY NUCLEAR OCCURRENCES § 840.4 Criterion I—Substantial discharge of radioactive material...
Code of Federal Regulations, 2013 CFR
2013-01-01
... 10 Energy 4 2013-01-01 2013-01-01 false Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite. 840.4 Section 840.4 Energy DEPARTMENT OF ENERGY EXTRAORDINARY NUCLEAR OCCURRENCES § 840.4 Criterion I—Substantial discharge of radioactive material...
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…
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.
3D homogenised strength criterion for masonry: Application to drystone retaining walls
NASA Astrophysics Data System (ADS)
Le, Hong Hanh; Garnier, Denis; Colas, Anne-Sophie; Terrade, Benjamin; Morel, Jean-Claude
2016-10-01
A 3D strength criterion for masonry is constructed based on yield design theory. Yield design homogenisation provides a rigorous theoretical framework to determine the yield strength properties of a periodic medium, based on the properties of its constituent materials. First, theoretical basis of 2D homogenisation of periodic media, and more particularly its application in the framework of yield design, will be retrieved. Then, 2D principles are extended to exhibit a 3D domain of running-bond masonry. This criterion is finally used to assess the stability of a drystone retaining wall loaded by an axle load, and theoretical results are compared to experimental data. Perspectives on this work are given as a conclusion.
A simple criterion for determining the dynamical stability of three-body systems
NASA Astrophysics Data System (ADS)
Black, D. C.
1982-09-01
Coplanar, prograde three-body systems (TBS) are discussed, emphasizing the specification of general criteria for determining whether such systems are dynamically stable. It is shown that the Graziani-Black (1981) criteria provide a quantitatively accurate characterization of the onset of dynamic instability for values of the dimensionless mass ranging from one millionth to one million. Harrington's (1977) general criterion and the Graziani-Black criterion are compared with results from analytic work that spans a 12-orders-of-magnitude variation in the mass ratios of the TBS components. Comparison of the Graziani-Black criteria with data for eight well-studied triple-star systems indicates that the observed lower limit for the ratio of periastron distance of the tertiary orbit to the semimajor axis of the binary orbit is due to dynamical instability rather than to cosmogonic processes.
An algebraic criterion for the onset of chaos in nonlinear dynamic systems
NASA Technical Reports Server (NTRS)
Unal, A.; Tobak, M.
1987-01-01
The correspondence between iterated integrals and a noncommutative algebra is used to recast the given dynamical system from the time domain to the Laplace-Borel transform domain. It is then shown that the following algebraic criterion has to be satisfied for the outset of chaos: the limit (as tau approaches infinity and x sub 0 approaches infinity) of ((sigma(k=0) (tau sup k) / (k* x sub 0 sup k)) G II G = 0, where G is the generating power series of the trajectories, the symbol II is the shuffle product (le melange) of the noncommutative algebra, x sub 0 is a noncommutative variable, and tau is the correlation parameter. In the given equation, symbolic forms for both G and II can be obtained by use of one of the currently available symbolic languages such as PLI, REDUCE, and MACSYMA. Hence, the criterion is a computer-algebraic one.
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
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.
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.
The Frequency Component of Water Quality Criterion Compliance Assessment Should be Data Driven.
Qian, Song S
2015-07-01
A numerical water quality criterion in the U.S. consists of three components representing magnitude, duration, and frequency. While magnitude and duration are well defined and conceptually unambiguous, the meaning of the frequency component is often debatable. We interpret the frequency component as a tool for accounting for uncertainty in estimating the mean concentration of a water quality constituent, after revisiting early works on environmental standards and criteria. Based on this interpretation, we illustrate management-related issues when using the default frequency of one exceedance in 3 years in compliance assessment. We propose a data-driven approach for estimating an appropriate frequency to ensure a consistent level of confidence in a water's compliance of a water quality criterion. The data-driven frequency is determined by water quality constituent concentration distribution characteristics and sample size. The method is illustrated using two examples.
The Frequency Component of Water Quality Criterion Compliance Assessment Should be Data Driven
NASA Astrophysics Data System (ADS)
Qian, Song S.
2015-07-01
A numerical water quality criterion in the U.S. consists of three components representing magnitude, duration, and frequency. While magnitude and duration are well defined and conceptually unambiguous, the meaning of the frequency component is often debatable. We interpret the frequency component as a tool for accounting for uncertainty in estimating the mean concentration of a water quality constituent, after revisiting early works on environmental standards and criteria. Based on this interpretation, we illustrate management-related issues when using the default frequency of one exceedance in 3 years in compliance assessment. We propose a data-driven approach for estimating an appropriate frequency to ensure a consistent level of confidence in a water's compliance of a water quality criterion. The data-driven frequency is determined by water quality constituent concentration distribution characteristics and sample size. The method is illustrated using two examples.
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
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
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.
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.
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)
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.
A simple criterion for determining the dynamical stability of three-body systems
NASA Technical Reports Server (NTRS)
Black, D. C.
1982-01-01
Coplanar, prograde three-body systems (TBS) are discussed, emphasizing the specification of general criteria for determining whether such systems are dynamically stable. It is shown that the Graziani-Black (1981) criteria provide a quantitatively accurate characterization of the onset of dynamic instability for values of the dimensionless mass ranging from one millionth to one million. Harrington's (1977) general criterion and the Graziani-Black criterion are compared with results from analytic work that spans a 12-orders-of-magnitude variation in the mass ratios of the TBS components. Comparison of the Graziani-Black criteria with data for eight well-studied triple-star systems indicates that the observed lower limit for the ratio of periastron distance of the tertiary orbit to the semimajor axis of the binary orbit is due to dynamical instability rather than to cosmogonic processes.
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
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 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%.
An error criterion for determining sampling rates in closed-loop control systems
NASA Technical Reports Server (NTRS)
Brecher, S. M.
1972-01-01
The determination of an error criterion which will give a sampling rate for adequate performance of linear, time-invariant closed-loop, discrete-data control systems was studied. The proper modelling of the closed-loop control system for characterization of the error behavior, and the determination of an absolute error definition for performance of the two commonly used holding devices are discussed. The definition of an adequate relative error criterion as a function of the sampling rate and the parameters characterizing the system is established along with the determination of sampling rates. The validity of the expressions for the sampling interval was confirmed by computer simulations. Their application solves the problem of making a first choice in the selection of sampling rates.
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
An Anisotropic Partial Regularity Criterion for the Navier-Stokes Equations
NASA Astrophysics Data System (ADS)
Kukavica, Igor; Rusin, Walter; Ziane, Mohammed
2016-07-01
In this paper, we address the partial regularity of suitable weak solutions of the incompressible Navier-Stokes equations. We prove an interior regularity criterion involving only one component of the velocity. Namely, if (u, p) is a suitable weak solution and a certain scale-invariant quantity involving only u 3 is small on a space-time cylinder {{Qr^{*}}(x_0,t_0)} , then u is regular at (x 0, t 0).
Earing Prediction in Cup Drawing using the BBC2008 Yield Criterion
NASA Astrophysics Data System (ADS)
Vrh, Marko; Halilovič, Miroslav; Starman, Bojan; Štok, Boris; Comsa, Dan-Sorin; Banabic, Dorel
2011-08-01
The paper deals with constitutive modelling of highly anisotropic sheet metals. It presents FEM based earing predictions in cup drawing simulation of highly anisotropic aluminium alloys where more than four ears occur. For that purpose the BBC2008 yield criterion, which is a plane-stress yield criterion formulated in the form of a finite series, is used. Thus defined criterion can be expanded to retain more or less terms, depending on the amount of given experimental data. In order to use the model in sheet metal forming simulations we have implemented it in a general purpose finite element code ABAQUS/Explicit via VUMAT subroutine, considering alternatively eight or sixteen parameters (8p and 16p version). For the integration of the constitutive model the explicit NICE (Next Increment Corrects Error) integration scheme has been used. Due to the scheme effectiveness the CPU time consumption for a simulation is comparable to the time consumption of built-in constitutive models. Two aluminium alloys, namely AA5042-H2 and AA2090-T3, have been used for a validation of the model. For both alloys the parameters of the BBC2008 model have been identified with a developed numerical procedure, based on a minimization of the developed cost function. For both materials, the predictions of the BBC2008 model prove to be in very good agreement with the experimental results. The flexibility and the accuracy of the model together with the identification and integration procedure guarantee the applicability of the BBC2008 yield criterion in industrial applications.
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…
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
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.
Algorithm and criterion of quality for assessing the packing of polymer microspheres
NASA Astrophysics Data System (ADS)
Kozlov, A. A.; Abdullaev, S. D.; Flid, V. R.; Gusev, S. A.
2016-09-01
An algorithm for assessing the quality of the packing of two-dimensional ordered structures, prepared using polymer microspheres 20 μm in diameter on a water surface, is proposed. An analysis is performed on the basis of optical microscopy images. The area of the largest ordered microsphere domain in an image is used as the quality criterion. The algorithm simplifies analysis of the ordered structures.
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.
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
The criterion for time symmetry of probabilistic theories and the reversibility of quantum mechanics
NASA Astrophysics Data System (ADS)
Holster, A. T.
2003-10-01
Physicists routinely claim that the fundamental laws of physics are 'time symmetric' or 'time reversal invariant' or 'reversible'. In particular, it is claimed that the theory of quantum mechanics is time symmetric. But it is shown in this paper that the orthodox analysis suffers from a fatal conceptual error, because the logical criterion for judging the time symmetry of probabilistic theories has been incorrectly formulated. The correct criterion requires symmetry between future-directed laws and past-directed laws. This criterion is formulated and proved in detail. The orthodox claim that quantum mechanics is reversible is re-evaluated. The property demonstrated in the orthodox analysis is shown to be quite distinct from time reversal invariance. The view of Satosi Watanabe that quantum mechanics is time asymmetric is verified, as well as his view that this feature does not merely show a de facto or 'contingent' asymmetry, as commonly supposed, but implies a genuine failure of time reversal invariance of the laws of quantum mechanics. The laws of quantum mechanics would be incompatible with a time-reversed version of our universe.
Verification of the Multi-Axial, Temperature and Time Dependent (MATT) Failure Criterion
NASA Technical Reports Server (NTRS)
Richardson, David E.; Macon, David J.
2005-01-01
An extensive test and analytical effort has been completed by the Space Shuttle's Reusable Solid Rocket Motor (KSKM) nozzle program to characterize the failure behavior of two epoxy adhesives (TIGA 321 and EA946). As part of this effort, a general failure model, the "Multi-Axial, Temperature, and Time Dependent" or MATT failure criterion was developed. In the initial development of this failure criterion, tests were conducted to provide validation of the theory under a wide range of test conditions. The purpose of this paper is to present additional verification of the MATT failure criterion, under new loading conditions for the adhesives TIGA 321 and EA946. In many cases, the loading conditions involve an extrapolation from the conditions under which the material models were originally developed. Testing was conducted using three loading conditions: multi-axial tension, torsional shear, and non-uniform tension in a bondline condition. Tests were conducted at constant and cyclic loading rates ranging over four orders of magnitude. Tests were conducted under environmental conditions of primary interest to the RSRM program. The temperature range was not extreme, but the loading ranges were extreme (varying by four orders of magnitude). It should be noted that the testing was conducted at temperatures below the glass transition temperature of the TIGA 321 adhesive. However for the EA946, the testing was conducted at temperatures that bracketed the glass transition temperature.
A new self-report inventory of dyslexia for students: criterion and construct validity.
Tamboer, Peter; Vorst, Harrie C M
2015-02-01
The validity of a Dutch self-report inventory of dyslexia was ascertained in two samples of students. Six biographical questions, 20 general language statements and 56 specific language statements were based on dyslexia as a multi-dimensional deficit. Dyslexia and non-dyslexia were assessed with two criteria: identification with test results (Sample 1) and classification using biographical information (both samples). Using discriminant analyses, these criteria were predicted with various groups of statements. All together, 11 discriminant functions were used to estimate classification accuracy of the inventory. In Sample 1, 15 statements predicted the test criterion with classification accuracy of 98%, and 18 statements predicted the biographical criterion with classification accuracy of 97%. In Sample 2, 16 statements predicted the biographical criterion with classification accuracy of 94%. Estimations of positive and negative predictive value were 89% and 99%. Items of various discriminant functions were factor analysed to find characteristic difficulties of students with dyslexia, resulting in a five-factor structure in Sample 1 and a four-factor structure in Sample 2. Answer bias was investigated with measures of internal consistency reliability. Less than 20 self-report items are sufficient to accurately classify students with and without dyslexia. This supports the usefulness of self-assessment of dyslexia as a valid alternative to diagnostic test batteries.
A new mixed-mode fracture criterion for large-scale lattice models
NASA Astrophysics Data System (ADS)
Sachau, T.; Koehn, D.
2014-01-01
Reasonable fracture criteria are crucial for the modeling of dynamic failure in computational lattice models. Successful criteria exist for experiments on the micro- and on the mesoscale, which are based on the stress that a bond experiences. In this paper, we test the applicability of these failure criteria to large-scale models, where gravity plays an important role in addition to the externally applied deformation. Brittle structures, resulting from these criteria, do not resemble the outcome predicted by fracture mechanics and by geological observations. For this reason we derive an elliptical fracture criterion, which is based on the strain energy stored in a bond. Simulations using the new criterion result in realistic structures. It is another great advantage of this fracture model that it can be combined with classic geological material parameters: the tensile strength σ0 and the shear cohesion τ0. The proposed fracture criterion is much more robust with regard to numerical strain increments than fracture criteria based on stress (e.g., Drucker-Prager). While we tested the fracture model only for large-scale structures, there is strong reason to believe that the model is equally applicable to lattice simulations on the micro- and on the mesoscale.
The effect of suspended particles on Jean's criterion for gravitational instability
NASA Astrophysics Data System (ADS)
Wollkind, David J.; Yates, Kemble R.
1990-07-01
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 N1/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.
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
Reviewing employee turnover: focusing on proximal withdrawal states and an expanded criterion.
Hom, Peter W; Mitchell, Terence R; Lee, Thomas W; Griffeth, Rodger W
2012-09-01
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, involuntary quits) and multiple types of staying. Guided by the premise that "everyone eventually leaves; no one stays with an organization forever," we also suggest considering where leavers end up-or post-exit destinations, such as another job, full-time parenting, or educational pursuits. We propose "proximal withdrawal states" that motivate members to participate or withdraw from organizations as an expanded criterion. These motivational states precede turnover and are derived from 2 overarching dimensions: desired employment status (whether employees want to stay or leave) and perceived volitional control (whether quit or stay decisions are completely up to them or at least partially under external regulation). Crossing these dimensions yields 4 prime states: enthusiastic leavers and stayers and reluctant leavers and stayers. We further subdivide these mind-sets into subtypes by differentiating employer from other forms of external control (e.g., family). Focusing on more common subtypes, we explain how they arise from particular motivational forces and profile how they differ by attitudes, behaviors, and turnover speed and destinations. We further discuss ways to measure this expanded criterion and proximal states (and subtypes) and investigate the latter's profiled differences. Finally, we discuss scientific and practical implications and future research directions.
A criterion for signal-based selection of wavelets for denoising intrafascicular nerve recordings.
Kamavuako, Ernest Nlandu; Jensen, Winnie; Yoshida, Ken; Kurstjens, Mathijs; Farina, Dario
2010-02-15
In this paper we propose a novel method for denoising intrafascicular nerve signals with the aim of improving action potential (AP) detection. The method is based on the stationary wavelet transform and thresholding of the wavelet coefficients. Since the choice of the mother wavelet substantially impact the performance, a criterion is proposed for selecting the optimal wavelet. The criterion for selection was based on the root mean square of the average of the output signal triggered by the detected APs. The mother wavelet was parameterized through the scaling filter, which allowed optimization through the proposed criterion. The method was tested on simulated signals and on experimental neural recordings. Experimental signals were recorded from the tibial branch of the sciatic nerve of three anaesthetized New Zealand white rabbits during controlled muscle stretches. The simulation results showed that the proposed method had an equivalent effect on AP detection performance (percentage of correct detection at 6 dB signal-to-noise ratio, mean+/-SD, 95.3+/-5.2%) to the a-posteriori choice of the best wavelet (96.1+/-3.6). Moreover, the AP detection after the proposed denoising method resulted in a correlation of 0.94+/-0.02 between the estimated spike rate and the muscle length. Therefore, the study proposes an effective method for selecting the optimal mother wavelet for denoising neural signals with the aim of improving AP detection.
Dufrenois, F; Noyer, J C
2013-02-01
Linear discriminant analysis, such as Fisher's criterion, is a statistical learning tool traditionally devoted to separating a training dataset into two or even several classes by the way of linear decision boundaries. In this paper, we show that this tool can formalize the robust linear regression problem as a robust estimator will do. More precisely, we develop a one-class Fischer's criterion in which the maximization provides both the regression parameters and the separation of the data in two classes: typical data and atypical data or outliers. This new criterion is built on the statistical properties of the subspace decomposition of the hat matrix. From this angle, we improve the discriminative properties of the hat matrix which is traditionally used as outlier diagnostic measure in linear regression. Naturally, we call this new approach discriminative hat matrix. The proposed algorithm is fully nonsupervised and needs only the initialization of one parameter. Synthetic and real datasets are used to study the performance both in terms of regression and classification of the proposed approach. We also illustrate its potential application to image recognition and fundamental matrix estimation in computer vision.
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.
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.
Chen, Liang-Hsuan; Hsueh, Chan-Ching
2007-06-01
Fuzzy regression models are useful to investigate the relationship between explanatory and response variables with fuzzy observations. Different from previous studies, this correspondence proposes a mathematical programming method to construct a fuzzy regression model based on a distance criterion. The objective of the mathematical programming is to minimize the sum of distances between the estimated and observed responses on the X axis, such that the fuzzy regression model constructed has the minimal total estimation error in distance. Only several alpha-cuts of fuzzy observations are needed as inputs to the mathematical programming model; therefore, the applications are not restricted to triangular fuzzy numbers. Three examples, adopted in the previous studies, and a larger example, modified from the crisp case, are used to illustrate the performance of the proposed approach. The results indicate that the proposed model has better performance than those in the previous studies based on either distance criterion or Kim and Bishu's criterion. In addition, the efficiency and effectiveness for solving the larger example by the proposed model are also satisfactory.
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
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.
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.
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 (
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.
A new design criterion based on pressure testing of torispherical heads
Kalnins, A.; Rana, M.D.
1996-08-01
Two vessels with torispherical heads were pressurized to destruction at the Praxair Tonawanda facility on September 12--13, 1994. The objective was to determine pressures at which observable or measurable indications of failure could be detected. Plastic limit pressures for the two heads were calculated at 190 and 240 psi, respectively. For Vessel 1, the only observable action was a slow formation of some waviness of the knuckle profile at approximately 600 psi. It lost pressure at 700 psi when a crack developed at a nozzle weld at the bottom of the shell. For Vessel 2, no indication of any sign of failure was observed until it burst at a pressure of 1,080 psi by a ductile fracture along the longitudinal weld of the shell. The main conclusion is that there is a problem in the application of the double elastic slope collapse criterion to torispherical heads. It was determined that when using this criterion a collapse pressure signaling excessive deformation cannot be determined with any certainty. Furthermore, the test data do not show anything at any of the calculated collapse pressures that suggests excessive deformation. Thus, the collapse pressures for torispherical heads cannot be confirmed by test. This leads to the inconsistency that if the collapse load is divided by a safety factor, say 1.5, to obtain an allowable pressure, the actual safety margin of the design is not known and may not be 1.5. For a material with sufficient ductility, the use of an estimated burst pressure appears preferable. A design criterion based on the membrane stress at the crown of a torispherical head reaching the ultimate tensile strength is proposed, which is simple, can be supported by theoretical arguments, and is shown to be conservative by current test results as well as by those of two previous test programs.
Fikslin, T.
1995-12-31
The use of the NOEL (No Effect Level) to determine safe concentrations of toxic substances has recently been questioned since the NOEL is generally estimated using hypothesis testing procedures, and is significantly affected by several test variables. An alternative approach involved the selection of a benchmark effect level and a statistical procedure to estimate the effluent concentration which would result in a fixed reduction of 10% in the growth of the fathead minnow, Pimephales promelas, or the reproduction of the cladoceran, Ceriodaphnia. Tests conducted on ambient samples and samples from 50 industrial and municipal effluents discharging to the tidal Delaware River were utilized to derive EC10 and NOEL values for each test. 72% of the ratios of the EC10 to NOEL values were less than or equal to 1.0 indicating that the NOEL determined using hypothesis testing procedures frequently exceeded a concentration which produces a 10% reduction in the response of test organisms compared to control organisms. A water quality criterion for chronic toxicity was developed using these results by calculating the goth percentile of the cumulative frequency distribution of the ratios. This procedure is similar to the one used by the US Environmental Protection Agency to develop the acute toxicity criterion of 0.3 Toxic Units. A 90th percentile value of 0.47 was calculated for this data set. A water quality criterion of 0.5 Toxic Units for chronic toxicity to aquatic life in the tidal Delaware River would therefore represent a more consistent and acceptable level of chronic toxicity based upon a fixed and minimal impairment in growth and reproduction.
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)
Image subband coding using an information-theoretic subband splitting criterion
NASA Astrophysics Data System (ADS)
Bayazit, Ulug; Pearlman, William A.
1995-03-01
It has been proved recently that for Gaussian sources with memory an ideal subband split will produce a coding gain for scalar or vector quantization of the subbands. Following the methodology of the proofs, we outline a method for successively splitting the subbands of a source, one at a time to obtain the largest coding gain. The subband with the largest theoretical rate reduction (TRR) is determined and split at each step of the decomposition process. The TRR is the difference between the rate in optimal encoding of N-tuples from a Gaussian source (or subband) and the rate for the same encoding of its subband decomposition. The TRR is a monotone increasing function of a so-called spectral flatness ratio, which involves the products of the eigenvalues of the source (subband) and subband decomposition covariance matrices of order N. These eigenvalues are estimated by the variances of the Discrete Cosine Transform, which approximates those of the optimal Karhunen Loeve Transform. After the subband decomposition hierarchy or tree is determined through the criterion of maximal TRR, each subband is encoded with a variable rate entropy constrained vector quantizer. Optimal rate allocation to subbands is done with the BFOS algorithm which does not require any source modelling. We demonstrate the benefit of using the criterion by comparing coding results on a two-level low-pass pyramidal decomposition with coding results on a two-level decomposition obtained using the criterion. For 60 MCFD (Motion Compensated Frame Difference) frames of the Salesman sequence an average rate- distortion advantage of 0.73 dB and 0.02 bpp and for 30 FD (Frame Difference) frames of Caltrain image sequence an average rate-distortion advantage of 0.41 dB and 0.013 bpp are obtained with the optimal decomposition over low-pass pyramidal decomposition.
ERIC Educational Resources Information Center
Raju, Nambury S.
1982-01-01
Rajaratnam, Cronbach and Gleser's generalizability formula for stratified-parallel tests and Raju's coefficient beta are generalized to estimate the reliability of a composite of criterion-referenced tests, where the parts have different cutting scores. (Author/GK)
NASA Astrophysics Data System (ADS)
Sekiguchi, C.; Hakoyama, T.; Kuwabara, T.; Fukiharu, H.
2016-08-01
A fracture criterion for sheet metals subjected to draw-bending is investigated using the concept of the forming limit stress criterion. The test material used is a 1.0-mm-thick high- strength steel sheet with a tensile strength of 590MPa. The specimen undergoes bendingunbending under tension when passing over the die profile. The drawing speed was set to 5-100 mm • s-1. The magnitude of true stress σDB when a specimen fractured has been precisely determined. Moreover, multiaxial tube expansion tests of the test material are performed to measure the forming limit stress σPT of the test material under plane-strain tension. It is found that σDB is larger than σPT by 2.8-6.3%. Therefore, it is concluded that the forming limit stress criterion is effective as a fracture criterion in draw-bending.
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}
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
Michałowska-Kaczmarczyk, Anna Maria; Asuero, Agustin G; Martin, Julia; Alonso, Esteban; Jurado, Jose Marcos; Michałowski, Tadeusz
2014-12-01
Rational functions of the Padé type are used for the calibration curve (CCM), and standard addition (SAM) methods purposes. In this paper, the related functions were applied to results obtained from the analyses of (a) nickel with use of FAAS method, (b) potassium according to FAES method, and (c) salicylic acid according to HPLC-MS/MS method. A uniform, integral criterion of nonlinearity of the curves, obtained according to CCM and SAM, is suggested. This uniformity is based on normalization of the approximating functions within the frames of a unit area.
Numerical investigation of BB-AMR scheme using entropy production as refinement criterion
NASA Astrophysics Data System (ADS)
Altazin, Thomas; Ersoy, Mehmet; Golay, Frédéric; Sous, Damien; Yushchenko, Lyudmyla
2016-03-01
In this work, a parallel finite volume scheme on unstructured meshes is applied to fluid flow for multidimensional hyperbolic system of conservation laws. It is based on a block-based adaptive mesh refinement strategy which allows quick meshing and easy parallelisation. As a continuation and as an extension of a previous work, the useful numerical density of entropy production is used as mesh refinement criterion combined with a local time-stepping method to preserve the computational time. Then, we numerically investigate its efficiency through several test cases with a confrontation with exact solution or experimental data.
A new criterion using information gain for action selection strategy in reinforcement learning.
Iwata, Kazunori; Ikeda, Kazushi; Sakai, Hideaki
2004-07-01
In this paper, we regard the sequence of returns as outputs from a parametric compound source. Utilizing the fact that the coding rate of the source shows the amount of information about the return, we describe l-learning algorithms based on the predictive coding idea for estimating an expected information gain concerning future information and give a convergence proof of the information gain. Using the information gain, we propose the ratio w of return loss to information gain as a new criterion to be used in probabilistic action-selection strategies. In experimental results, we found that our w-based strategy performs well compared with the conventional Q-based strategy.
Rayleigh criterion and acoustic energy balance in unconfined self-sustained oscillating flames
Durox, D.; Schuller, T.; Noiray, N.; Birbaud, A.L.; Candel, S.
2009-01-15
Instabilities of confined combustion systems are often discussed in terms of the Rayleigh criterion, which provides a necessary condition for unstable operation and is commonly used to distinguish driving and damping regions. The analysis is also carried out in some cases by making use of an acoustic energy balance in which the Rayleigh term acts as a source. The case of unconfined flames is less well documented but of importance in practical systems used in heating and drying. This study is motivated by problems of self-sustained oscillations of radiant burners for domestic or industrial processes and of various other types of open flames. Application of the Rayleigh criterion and of the balance of acoustic energy to oscillations arising in such unconfined systems is examined. The objective is to see if the Rayleigh condition is fulfilled and to show how the different perturbed variables are linked to each other to develop an unstable oscillation. These issues are investigated by experiments in two geometries. The first case relates to a single ''V''- or ''M''-shaped flame formed by a burner behaving like a Helmholtz resonator. The second geometry features a collection of conical flames (CCF) established by a multipoint injector. This system is fed by a manifold that features a set of plane modes and resonates like an organ pipe at frequencies corresponding to odd multiples of the quarter wave. The Rayleigh criterion and a related result written in the form of an acoustic energy balance are used to define conditions of instability. A link is established between the pressure signal radiated by the burner and the total heat release rate perturbation yielding the phase lag between these two variables and providing conditions for unstable operation. Systematic experiments carried out in the two burner geometries and model predictions are in good agreement indicating that the Rayleigh source term is positive and that the criterion is well fulfilled by the wavefield
Rayleigh criterion and acoustic energy balance in unconfined self-sustained oscillating flames
Durox, D.; Schuller, T.; Noiray, N.; Birbaud, A.L.; Candel, S.
2008-11-15
Instabilities of confined combustion systems are often discussed in terms of the Rayleigh criterion, which provides a necessary condition for unstable operation and is commonly used to distinguish driving and damping regions. The analysis is also carried out in some cases by making use of an acoustic energy balance in which the Rayleigh term acts as a source. The case of unconfined flames is less well documented but of importance in practical systems used in heating and drying. This study is motivated by problems of self-sustained oscillations of radiant burners for domestic or industrial processes and of various other types of open flames. Application of the Rayleigh criterion and of the balance of acoustic energy to oscillations arising in such unconfined systems is examined. The objective is to see if the Rayleigh condition is fulfilled and to show how the different perturbed variables are linked to each other to develop an unstable oscillation. These issues are investigated by experiments in two geometries. The first case relates to a single ''V''- or ''M''-shaped flame formed by a burner behaving like a Helmholtz resonator. The second geometry features a collection of conical flames (CCF) established by a multipoint injector. This system is fed by a manifold that features a set of plane modes and resonates like an organ pipe at frequencies corresponding to odd multiples of the quarter wave. The Rayleigh criterion and a related result written in the form of an acoustic energy balance are used to define conditions of instability. A link is established between the pressure signal radiated by the burner and the total heat release rate perturbation yielding the phase lag between these two variables and providing conditions for unstable operation. Systematic experiments carried out in the two burner geometries and model predictions are in good agreement indicating that the Rayleigh source term is positive and that the criterion is well fulfilled by the wavefield
Some problems on rf breakdown in room temperature accelerator structure, a possible criterion
Wang, J.W.
1986-04-01
The discussion is confined to high gradient, room-temperature accelerators which have clean well-finished cavity surfaces and good vacuum conditions. Breakdown-initiating mechanisms due to ''cold'' field electron emission occurring at isolated sites on broad-area cavity surfaces, where the field is enhanced, are described. The influences of an alternating field and transition time tunneling are taken into account. The thermal instability resulting in vacuum voltage breakdown is hypothesized to derive a new criterion for room-temperature accelerator structure. 18 refs., 5 figs. (DWL)
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.
Criterion for Bose-Einstein condensation in a harmonic trap in the case with attractive interactions
Gajda, Mariusz
2006-02-15
Using a model many-body wave function I analyze the standard criterion for Bose-Einstein condensation and its relation to coherence properties of the system. I pay special attention to an attractive condensate under such a condition that a characteristic length scale of the spatial extension of its center of mass differs significantly from length scales of relative coordinates. I show that although no interference fringes are produced in the two-slit Young interference experiment performed on this system, fringes of a high visibility can be observed in a conditional simultaneous detection of two particles.
Wang, Gang; Wang, Zhizhong; Chen, Weiting; Zhuang, Jun
2006-10-01
In this paper we present an optimal wavelet packet (OWP) method based on Davies-Bouldin criterion for the classification of surface electromyographic signals. To reduce the feature dimensionality of the outputs of the OWP decomposition, the principle components analysis was employed. Then we chose a neural network classifier to discriminate four types of prosthesis movements. The proposed method achieved a mean classification accuracy of 93.75%, which outperformed the method using the energy of wavelet packet coefficients (with mean classification accuracy 86.25%) and the fuzzy wavelet packet method (87.5%).
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)
Zhou, Yong; Pokorný, Milan
2009-12-01
We improve the regularity criterion for the incompressible Navier-Stokes equations in the full three-dimensional space involving the gradient of one velocity component. The method is based on recent results of Cao and Titi [see "Regularity criteria for the three dimensional Navier-Stokes equations," Indiana Univ. Math. J. 57, 2643 (2008)] and Kukavica and Ziane [see "Navier-Stokes equations with regularity in one direction," J. Math. Phys. 48, 065203 (2007)]. In particular, for s ɛ[2,3], we get that the solution is regular if ∇u3ɛLt(0,T;Ls(R3)), 2/t+3/s≤23/12.
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.
NASA Astrophysics Data System (ADS)
Diamant, Idit; Shalhon, Moran; Goldberger, Jacob; Greenspan, Hayit
2016-03-01
Classification of clustered breast microcalcifications into benign and malignant categories is an extremely challenging task for computerized algorithms and expert radiologists alike. In this paper we present a novel method for feature selection based on mutual information (MI) criterion for automatic classification of microcalcifications. We explored the MI based feature selection for various texture features. The proposed method was evaluated on a standardized digital database for screening mammography (DDSM). Experimental results demonstrate the effectiveness and the advantage of using the MI-based feature selection to obtain the most relevant features for the task and thus to provide for improved performance as compared to using all features.
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.
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.
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.
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.
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
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
Suboptimal criterion setting in a perceptual choice task with asymmetric reinforcement.
Stüttgen, Maik C; Kasties, Nils; Lengersdorf, Daniel; Starosta, Sarah; Güntürkün, Onur; Jäkel, Frank
2013-06-01
Performance on psychophysical tasks is influenced by a variety of non-sensory factors, most notably the magnitude or probability of reinforcement following correct responses. When reinforcement probability is unequal for hits and correct rejections, signal detection theory specifies an optimal decision criterion which maximizes the number of reinforcers. We subjected pigeons to a task in which six different stimuli (shades of gray) had to be assigned to one of two categories. Animals were confronted with asymmetric reinforcement schedules in which correct responses to five of the stimuli were reinforced with a probability of 0.5, while correct responses to the remaining stimulus were extinguished. The subjects' resultant choice probabilities clearly deviated from those predicted by a maximization account. More specifically, the magnitude of the choice bias increased with the distance of the to-be-extinguished stimulus to the category boundary, a pattern opposite to that posited by maximization. The present and a previous set of results in which animals performed optimally can be explained by a simple choice mechanism in which a variable decision criterion is constantly updated according to a leaky integration of incomes attained from both response options.
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
In search of a new governing failure criterion for torispherical heads
Kalnins, A.; Updike, D.P.; Rana, M.D.
1995-12-01
The failure criterion that governs the present design rules of formed heads in Section 8/Div. 2 of the ASME B and PV Code limits crown displacement upon a single application of pressure, and it does so by means of a calculated collapse pressure. One problem with the rules is that they require greater head thicknesses than those of Section 8/Div. 1. Another problem is that recent test data taken for two formed heads have shown no signs of head displacements or deformations that could have rendered the heads unserviceable at pressures substantially higher than the calculated collapse pressures. Any link between the calculated collapse pressures and the failures of the test heads could not be established. The main thesis proposed in the paper is that such a link does not exist for torispherical heads in general. The reason for this is investigated theoretically and attributed to the geometric strengthening of heads, as they deform. It is recommended that the reasons for limiting displacements or deformations for a single application of pressure be reviewed and, if needed, a new failure criterion defined, or other failure modes, such as tensile plastic instability (burst), be considered. The latter mode is described and options for its evaluation are presented in this paper. The protection of torispherical heads against the failure modes of low-cycle fatigue and incremental plastic growth upon cyclic loading, which are controlled by shakedown, is not covered in this paper but is left to future investigations.
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.
Suboptimal criterion setting in a perceptual choice task with asymmetric reinforcement.
Stüttgen, Maik C; Kasties, Nils; Lengersdorf, Daniel; Starosta, Sarah; Güntürkün, Onur; Jäkel, Frank
2013-06-01
Performance on psychophysical tasks is influenced by a variety of non-sensory factors, most notably the magnitude or probability of reinforcement following correct responses. When reinforcement probability is unequal for hits and correct rejections, signal detection theory specifies an optimal decision criterion which maximizes the number of reinforcers. We subjected pigeons to a task in which six different stimuli (shades of gray) had to be assigned to one of two categories. Animals were confronted with asymmetric reinforcement schedules in which correct responses to five of the stimuli were reinforced with a probability of 0.5, while correct responses to the remaining stimulus were extinguished. The subjects' resultant choice probabilities clearly deviated from those predicted by a maximization account. More specifically, the magnitude of the choice bias increased with the distance of the to-be-extinguished stimulus to the category boundary, a pattern opposite to that posited by maximization. The present and a previous set of results in which animals performed optimally can be explained by a simple choice mechanism in which a variable decision criterion is constantly updated according to a leaky integration of incomes attained from both response options. PMID:23466903
A new approach to a damage risk criterion for weapons impulses.
Price, G R; Kalb, J T
1991-01-01
Existing damage-risk criteria for weapons impulses suffer from their lack of a theoretical basis, thereby limiting their generalizability and utility. Furthermore, a number of studies now indicate that they may be inaccurate for impulses with energy in the low frequency region (Dancer & al., 1985; Patterson & al., 1985; Price & al., 1989). We have approached the problem by modeling the ear mathematically as a means of gaining insight into the loss processes. In the model, the external and middle ears are linear at lower intensities; however, the stapes displacement is limited to 20 microns, as would be expected on anatomical/physical grounds. Susceptibility, in the inner ear, is modeled as mechanical stress, a function of basilar membrane displacement and number of flex cycles. The model, which is executable on a PC-based computer, reproduces the data on the ear that can be measured at lower intensities. It also ranks the known hazard from impulses in the correct order, explains the finding of loss in mid-cochlea regardless of spectral location of the weapons impulse, and suggests that the greatest hazard comes from that portion of the acoustic wave in which pressures cross through ambient and at a rate consistent with energy in the mid-range. Because the model is theoretically based, it has the potential for use as the basis for a damage risk criterion for impulse noise as well as for a design criterion for weapons.
Cavalli, R O; Berghe, E V; Lavens, P; Nguyen, T T; Wille, M; Sorgeloos, P
2000-03-01
The feasibility of a short-term ammonia toxicity test as an evaluation criterion for larval quality was assessed in three trials. In each one, Macrobrachium rosenbergii larvae originating from the same spawn were nutritionally differentiated in two groups by feeding them either a nutrient-rich (Artemia nauplii enriched for 24 h with n-3 highly unsaturated fatty acids (HUFA) and ascorbic acid (AA)) or a nutrient-poor diet (Artemia nauplii starved for 24 h). Throughout their development, larvae from both treatments were exposed during 24 h to six concentrations of total ammonia (NH(4)(+)+NH(3)) and a control (no ammonia added). Based on mortality rates, the median lethal concentration for 50% of the population (LC(50)) was estimated. As expected from earlier work, larvae fed the optimal diet presented higher n-3 HUFA and AA contents as well as higher growth and metamorphosis rates. From the moment the effect of diet quality was analytically detectable in the tissues of the larvae, the ammonia test was able to distinguish both groups of larvae. Differences in ammonia tolerance were observed as early as larval stage 4 and remained evident throughout larval development. The short-term ammonia toxicity test proved to be a valuable, sensitive and reproducible criterion for the establishment of larval quality. PMID:11790354
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
Watanabe, Kenji; Hidaka, Akinori; Otsu, Nobuyuki; Kurita, Takio
2012-01-01
In time-resolved spectroscopy, composite signal sequences representing energy transfer in fluorescence materials are measured, and the physical characteristics of the materials are analyzed. Each signal sequence is represented by a sum of non-negative signal components, which are expressed by model functions. For analyzing the physical characteristics of a measured signal sequence, the parameters of the model functions are estimated. Furthermore, in order to quantitatively analyze real measurement data and to reduce the risk of improper decisions, it is necessary to obtain the statistical characteristics from several sequences rather than just a single sequence. In the present paper, we propose an automatic method by which to analyze composite signals using non-negative factorization and an information criterion. The proposed method decomposes the composite signal sequences using non-negative factorization subjected to parametric base functions. The number of components (i.e., rank) is also estimated using Akaike's information criterion. Experiments using simulated and real data reveal that the proposed method automatically estimates the acceptable ranks and parameters.
Human dignity in international policy documents: a useful criterion for public policy?
de Melo-Martín, Inmaculada
2011-01-01
Current developments in biomedicine are presenting us with difficult ethical decisions and raising complex policy questions about how to regulate these new developments. Particularly vexing for governments have been issues related to human embryo experimentation. Because some of the most promising biomedical developments, such as stem cell research and nuclear somatic transfer, involve such experimentation, several international bodies have drafted documents aimed to provide guidance to governments when developing biomedical science policy. Here I focus on two such documents: the Council of Europe's Convention for the Protection of Human Rights and Dignity of the Human Being and the Additional Protocol to the Convention for the Protection of Human Rights and Dignity of the Human Being. I argue that by using human dignity as a criterion to determine the permissibility of particular human embryo research practices, these documents cannot aid in identifying research that would be contrary to human dignity. Thus, they fail to guide public policy on embryo experimentation. Their use of human dignity as a criterion makes their task of offering guidance unfeasible because the concept as used in these documents is too vague and is applied in contradictory ways. I discuss the main goals of these documents and their claims in relation to human embryo research. I then discuss how they have influenced public policy in several countries. Finally, I show that although these Council of Europe treaties attempt to serve as public policy guides in the area of embryo research, they fail to do so.
A risk-based cleanup criterion for PCE in soil. [Tetrachloroethylene
Daniels, J.I.; McKone, T.E.; Hall, L.C.
1990-09-26
The most important attribute of a chemical contaminant at a hazardous-wastes site for decision makers to consider with regard to its cleanup is the potential risk associated with human exposure. For this reason we have developed a strategy for establishing a risk-based cleanup criterion for chemicals in soil. We describe this strategy by presenting a cleanup criterion for tetrachloroethylene (PCE) in soil associated with a representative California landscape. We being by discussing the environmental fate and transport model, developed at the Lawrence Livermore National Laboratory (LLNL), that we used to predict the equilibrium concentration of PCE in five environmental media from a steady-state source in soil. Next, we explain the concept and application of pathway-exposure factors (PEFs), the hazard index, and cancer-potency factors (CPFs) for translating the predicted concentrations of PCE into estimated potential hazard or risk for hypothetically exposed individuals. Finally, the relationship between concentration and an allowable level of risk is defined and the societal and financial implications are discussed. 22 refs., 6 tabs.
Watanabe, Kenji; Hidaka, Akinori; Otsu, Nobuyuki; Kurita, Takio
2012-01-01
In time-resolved spectroscopy, composite signal sequences representing energy transfer in fluorescence materials are measured, and the physical characteristics of the materials are analyzed. Each signal sequence is represented by a sum of non-negative signal components, which are expressed by model functions. For analyzing the physical characteristics of a measured signal sequence, the parameters of the model functions are estimated. Furthermore, in order to quantitatively analyze real measurement data and to reduce the risk of improper decisions, it is necessary to obtain the statistical characteristics from several sequences rather than just a single sequence. In the present paper, we propose an automatic method by which to analyze composite signals using non-negative factorization and an information criterion. The proposed method decomposes the composite signal sequences using non-negative factorization subjected to parametric base functions. The number of components (i.e., rank) is also estimated using Akaike's information criterion. Experiments using simulated and real data reveal that the proposed method automatically estimates the acceptable ranks and parameters. PMID:22396759
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
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.
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
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
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
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
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
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
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.
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
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.
Spatiotemporal generalization of the Harris criterion and its application to diffusive disorder
NASA Astrophysics Data System (ADS)
Vojta, Thomas; Dickman, Ronald
2016-03-01
We investigate how a clean continuous phase transition is affected by spatiotemporal disorder, i.e., by an external perturbation that fluctuates in both space and time. We derive a generalization of the Harris criterion for the stability of the clean critical behavior in terms of the space-time correlation function of the external perturbation. As an application, we consider diffusive disorder, i.e., an external perturbation governed by diffusive dynamics, and its effects on a variety of equilibrium and nonequilibrium critical points. We also discuss the relation between diffusive disorder and diffusive dynamical degrees of freedom in the example of model C of the Hohenberg-Halperin classification and comment on Griffiths singularities.
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.
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.
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
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.
NASA Astrophysics Data System (ADS)
Mechdene, Mohamed; Gala, Sadek; Guo, Zhengguang; Ragusa, Alessandra Maria
2016-10-01
This work establishes a sufficient condition for the regularity criterion of the Boussinesq equation in terms of the derivative of the pressure in one direction. It is shown that if the partial derivative of the pressure {partial 3π } satisfies the logarithmical Serrin-type condition int0TVert partial 3π (s)Vert_{L^{λ }}q/1+ln (1+Vert θ Vert_{L4)} {d}s < ∞ quad {with}quad2/q+3/λ =7/4quad {and}quad12/7 < λ ≤ ∞, then the solution {(u,θ )} remains smooth on {[0,T]}. Compared to the Navier-Stokes result, there is a logarithmic correction involving {θ} in the denominator.
Fisher's ratio-based criterion for finding endmembers in hyperspectral imagery
NASA Astrophysics Data System (ADS)
Gao, Cheng; Chen, Shih-Yu; Chang, Chein-I.
2014-05-01
Endmember extraction has recently received considerable interest in hyperspectral imagery. However, several issues in endmember extraction may have been overlooked. The first and foremost is the term of using endmember extraction. Many algorithms claimed to be endmember extraction algorithms actually do not extract true endmembers but rather find potential endmember candidates, referred to as virtual endmembers (VEs). Secondly, how difficult for an algorithm to find VEs is primarily determined by two key factors, endmember variability and endmember discriminability. While the former issue has been addressed recently in the literature, the latter issue is yet explored and has not been investigated before. This paper re-invents a wheel by developing a Fisher's ratio approach to finding VEs using Fisher's ratio criterion which is defined by ratio of endmember variability to endmember discriminability.
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.
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.
Inhibition of return: sensitivity and criterion as a function of response time.
Ivanoff, Jason; Klein, Raymond M
2006-08-01
Inhibition of return (IOR) refers to a mechanism that results in a performance disadvantage typically observed when targets are presented at a location once occupied by a cue. Although the time course of the phenomenon--from the cue to the target--has been well studied, the time course of the effect--from target to response--is unknown. In 2 experiments, the effect of IOR upon sensitivity and response criterion under different levels of speed stress was examined. In go/no-go and choice reaction time tasks, IOR had at least 2 distinct effects on information processing. Early in target processing, before sufficient target information has accrued, there is a bias against responding to cued targets. Later, as target information is allowed to accrue, IOR reduces sensitivity to the target's nonspatial feature. Three accounts relating to the early bias effect of IOR and the late effect of IOR on sensitivity are offered. PMID:16846287
Examining the criterion-related validity of the Pervasive Developmental Disorder Behavior Inventory.
McMorris, Carly A; Perry, Adrienne
2015-04-01
The Pervasive Developmental Disorder Behavior Inventory is a questionnaire designed to aid in the diagnosis of pervasive developmental disorders or autism spectrum disorders. The Pervasive Developmental Disorder Behavior Inventory assesses adaptive and maladaptive behaviors associated with pervasive developmental disorders and provides an age-standardized Autism Composite score. In previous research, the Pervasive Developmental Disorder Behavior Inventory has demonstrated moderate to strong reliability and validity. This study aimed to replicate and extend previous research by investigating the criterion-related validity of the Pervasive Developmental Disorder Behavior Inventory. Data from 40 children were analyzed in relation to other measures. The Pervasive Developmental Disorder Behavior Inventory adaptive scores were moderately correlated with cognitive and adaptive behavior scores as expected. However, no significant correlations were found between the maladaptive and Autism Composite scores of the Pervasive Developmental Disorder Behavior Inventory and the Childhood Autism Rating Scale. Results lead to concerns regarding the validity of some scores of the Pervasive Developmental Disorder Behavior Inventory.
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.
Selection Criterion of Gauges for Vacuum Measurements of Systems with Diverse Ranges
NASA Astrophysics Data System (ADS)
Akram, H. M.; Fasih, A.
Basically a vacuum gauge is a key that opens the secrets of a closed vacuum system, indicates what is happening inside the sealed makeup and has the facility to control it through evacuation system. But for the broad vacuum range, all the goings-on are not made known or commanded by a particular vacuum gauge. Consequently, various gauges of special types are used to accurately measure the vacuum of diverse ranges, together with the requisite services. Therefore, the selection of proper gauge in favor of exact vacuum metrology in conjunction with extra actions, for a particular vacuum work, is of primary importance. There are many factors that affect the appropriate gauge selection. In this paper, selection criterion for suitable vacuum gauge, supportive for accurate vacuum measurements and other critical functions of the required range, has briefly been discussed that can make the task of gauge selection simpler and exact.
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
NASA Astrophysics Data System (ADS)
Hu, Guolin; Yang, Lianfa; Liu, Jianwei
2013-12-01
Tube hydroforming (THF) is an attractive manufacturing process in automotive industry, and forming limit diagram (FLD) is a significant strategy to assess the formability of THF. In present study, a method of predicting the FLD for THF is developed based on finite element (FE) simulation with the strain rate change criterion (SRCC) as a failure criteria of identify localized necking. FE simulations under various linear loading paths are carried out to obtain the strain information. The equivalent strain rates at potential fracturing and its adjacent nodes are calculated and utilized with SRCC to distinguish the onset of fracturing in FE simulation. The fracture strains at the two nodes under various linear loading paths are abstracted for establishing FLD. Tube hydo-bulging experiments under the linear loading paths have been conducted to verify the prediction method of FLD, and the results show that this prediction method bears good agreement with experimental data.
The leg-to-body ratio as a human aesthetic criterion.
Swami, Viren; Einon, Dorothy; Furnham, Adrian
2006-12-01
There are surprisingly few empirical studies on the aesthetic appeal of human legs, examining such variables as length or shape. The human legs are conspicuous in erotic contexts, but few studies have experimentally tested preferences for longer legs. This study examined the utility of the human leg-to-body ratio (LBR) as a specific aesthetic criterion among 71 British undergraduates. Participants rated for physical attractiveness line drawings that varied in five levels of LBR. The results showed that a longer LBR was preferred as maximally attractive in women, whereas a shorter LBR was preferred in men. Evolutionary psychological and socio-cultural explanations for this aesthetic preference are discussed, and the study's limitations are considered. PMID:18089235
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.
Detecting deception in children: event familiarity affects criterion-based content analysis ratings.
Pezdek, Kathy; Morrow, Anne; Blandon-Gitlin, Iris; Goodman, Gail S; Quas, Jodi A; Saywitz, Karen J; Bidrose, Sue; Pipe, Margaret-Ellen; Rogers, Martha; Brodie, Laura
2004-02-01
Statement Validity Assessment (SVA) is a comprehensive credibility assessment system, with the Criterion-Based Content Analysis (CBCA) as a core component. Worldwide, the CBCA is reported to be the most widely used veracity assessment instrument. We tested and confirmed the hypothesis that CBCA scores are affected by event familiarity; descriptions of familiar events are more likely to be judged true than are descriptions of unfamiliar events. CBCA scores were applied to transcripts of 114 children who recalled a routine medical procedure (control) or a traumatic medical procedure that they had experienced one time (relatively unfamiliar) or multiple times (relatively familiar). CBCA scores were higher for children in the relatively familiar than the relatively unfamiliar condition, and CBCA scores were significantly correlated with age. Results raise serious questions regarding the forensic suitability of the CBCA for assessing the veracity of children's accounts.
A Criterion for the Complete Deposition of Magnetic Beads on the Walls of Microchannels.
Pallares, Jordi
2016-01-01
This paper analyzes numerical simulations of the trajectories of magnetic beads in a microchannel, with a nearby permanent cubical magnet, under different flow and magnetic conditions. Analytically derived local fluid velocities and local magnetic forces have been used to track the particles. A centered position and a lateral position of the magnet above the microchannel are considered. The computed fractions of deposited particles on the walls are compared successfully with a new theoretically derived criterion that imposes a relation between the sizes of the magnet and the microchannel and the particle Stokes and Alfvén numbers to obtain the complete deposition of the flowing particles on the wall. In the cases in which all the particles, initially distributed uniformly across the section of the microchannel, are deposited on the walls, the simulations predict the accumulation of the major part of particles on the wall closest to the magnet and near the first half of the streamwise length of the magnet.
Janssens, Annelies; Goossens, Luc; Van Den Noortgate, Wim; Colpin, Hilde; Verschueren, Karine; Van Leeuwen, Karla
2015-08-01
Uncertainty persists regarding adequate measurement of parenting behavior during early adolescence. The present study aimed to clarify the conceptual structure of parenting by evaluating three different models that include support, psychological control, and various types of behavioral control (i.e., proactive, punitive, and harsh punitive control). Furthermore, we examined measurement invariance of parenting ratings by 1,111 Flemish adolescents from Grade 7 till 9, their mother, and father. Finally, criterion validity of parenting ratings was estimated in relation to adolescent problem behavior. Results supported a five-factor parenting model indicating multiple aspects of behavioral control, with punitive and harsh punitive control as more intrusive forms and proactive control as a more supportive form. Similar constructs were measured for adolescents, mothers, and fathers (i.e., configural and metric invariance), however on a different scale (i.e., scalar noninvariance). Future research and clinical practices should acknowledge these findings in order to fully grasp the parenting process.
Niu, Haiyang; Chen, Xing-Qiu; Liu, Peitao; Xing, Weiwei; Cheng, Xiyue; Li, Dianzhong; Li, Yiyi
2012-01-01
Traditional strengthening ways, such as strain, precipitation, and solid-solution, come into effect by pinning the motion of dislocation. Here, through first-principles calculations we report on an extra-electron induced covalent strengthening mechanism, which alters chemical bonding upon the introduction of extra-valence electrons in the matrix of parent materials. It is responsible for the brittle and high-strength properties of Al12W-type compounds featured by the typical fivefold icosahedral cages, which are common for quasicrystals and bulk metallic glasses (BMGs). In combination with this mechanism, we generalize ductile-to-brittle criterion in a universal hyperbolic form by integrating the classical Pettifor's Cauchy pressure with Pugh's modulus ratio for a wide variety of materials with cubic lattices. This study provides compelling evidence to correlate Pugh's modulus ratio with hardness of materials and may have implication for understanding the intrinsic brittleness of quasicrystals and BMGs. PMID:23056910
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
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
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<
Jiang, Xinning; Jiang, Xiaogang; Han, Guanghui; Ye, Mingliang; Zou, Hanfa
2007-01-01
Background In proteomic analysis, MS/MS spectra acquired by mass spectrometer are assigned to peptides by database searching algorithms such as SEQUEST. The assignations of peptides to MS/MS spectra by SEQUEST searching algorithm are defined by several scores including Xcorr, ΔCn, Sp, Rsp, matched ion count and so on. Filtering criterion using several above scores is used to isolate correct identifications from random assignments. However, the filtering criterion was not favorably optimized up to now. Results In this study, we implemented a machine learning approach known as predictive genetic algorithm (GA) for the optimization of filtering criteria to maximize the number of identified peptides at fixed false-discovery rate (FDR) for SEQUEST database searching. As the FDR was directly determined by decoy database search scheme, the GA based optimization approach did not require any pre-knowledge on the characteristics of the data set, which represented significant advantages over statistical approaches such as PeptideProphet. Compared with PeptideProphet, the GA based approach can achieve similar performance in distinguishing true from false assignment with only 1/10 of the processing time. Moreover, the GA based approach can be easily extended to process other database search results as it did not rely on any assumption on the data. Conclusion Our results indicated that filtering criteria should be optimized individually for different samples. The new developed software using GA provides a convenient and fast way to create tailored optimal criteria for different proteome samples to improve proteome coverage. PMID:17761002
Evers, Kathinka; Kilander, Lena; Lindau, Maria
2007-02-01
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 tomography (PET) participated in the study). The results indicated that insight was present in three out of eight patients, and that insight appears to be a heterogeneous concept. Two types of insight emerged: Emotional insight associated with frontotemporal functions, and cognitive insight, related to posterior cognitive functions. These results suggest that loss of insight should not serve as a core criterion on FTD, but serves well as a supportive criterion of the disease. PMID:16914245
Hoffman, Brian J; Kennedy, Colby L; LoPilato, Alexander C; Monahan, Elizabeth L; Lance, Charles E
2015-07-01
This study uses meta-analysis and a qualitative review of exercise descriptions to evaluate the content, criterion-related, construct, and incremental validity of 5 commonly used types of assessment center (AC) exercises. First, we present a meta-analysis of the relationship between 5 types of AC exercises with (a) the other exercise types, (b) the 5-factor model of personality, (c) general mental ability (GMA), and (d) relevant criterion variables. All 5 types of exercises were significantly related to criterion variables (ρ = .16-.19). The nomological network analyses suggested that the exercises tend to be modestly associated with GMA, Extraversion and, to a lesser extent, Openness to Experience but largely unrelated to Agreeableness, Conscientiousness, and Emotional Stability. Finally, despite sparse reporting in primary studies, a content analysis of exercise descriptions yielded some evidence of complexity, ambiguity, interpersonal interaction, and fidelity but not necessarily interdependence. (PsycINFO Database Record
Age as a Criterion for Setting Priorities in Health Care? A Survey of the German Public View
Diederich, Adele; Winkelhage, Jeannette; Wirsik, Norman
2011-01-01
Although the German health care system has budget constraints similar to many other countries worldwide, a discussion on prioritization has not gained the attention of the public yet. To probe the acceptance of priority setting in medicine, a quantitative survey representative for the German public (n = 2031) was conducted. Here we focus on the results for age, a highly disputed criterion for prioritizing medical services. This criterion was investigated using different types of questionnaire items, from abstract age-related questions to health care scenarios, and discrete choice settings, all performed within the same sample. Several explanatory variables were included to account for differences in preference; in particular, interviewee's own age but also his or her sex, socioeconomic status, and health status. There is little evidence that the German public accepts age as a criterion to prioritize health care services. PMID:21904600
NASA Astrophysics Data System (ADS)
Kurzeja, Patrick
2016-05-01
Modern imaging techniques, increased simulation capabilities and extended theoretical frameworks, naturally drive the development of multiscale modelling by the question: which new information should be considered? Given the need for concise constitutive relationships and efficient data evaluation; however, one important question is often neglected: which information is sufficient? For this reason, this work introduces the formalized criterion of subscale sufficiency. This criterion states whether a chosen constitutive relationship transfers all necessary information from micro to macroscale within a multiscale framework. It further provides a scheme to improve constitutive relationships. Direct application to static capillary pressure demonstrates usefulness and conditions for subscale sufficiency of saturation and interfacial areas.
NASA Astrophysics Data System (ADS)
Cazacu, Oana; Stewart, Joel B.
2013-05-01
A new analytic plastic potential is developed using a rigorous limit analysis approach. Conditions of homogeneous boundary strain rate are imposed on every cylinder concentric with the cavity. It is shown that, due to the tension-compression asymmetry of the incompressible matrix, the third invariant of the stress deviator has a strong influence on the yielding of the porous solid. New and intriguing results are obtained; namely, for axisymmetric loadings and plane strain conditions, the stress state at yielding is not hydrostatic. In the case when the matrix has the same yield in tension as in compression, the new criterion reduces to Gurson's criterion for cylindrical voids.
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
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
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
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…
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
Stewart, Kelise K.; Carr, James E.; Brandt, Charles W.; McHenry, Meade M.
2007-01-01
The present study evaluated the effects of both a traditional lecture and the conservative dual-criterion (CDC) judgment aid on the ability of 6 university students to visually inspect AB-design line graphs. The traditional lecture reliably failed to improve visual inspection accuracy, whereas the CDC method substantially improved the performance…
ERIC Educational Resources Information Center
Dishner, Ernest K.; And Others
The purpose of this study was to examine the degree of forgetting of meaningful information learned to 90% criterion by thirty-nine college students in two introductory reading methods classes in the word recognition (exclusive of phonics) module of those classes. The amount of information gained was compared to forgetting to determine the percent…
ERIC Educational Resources Information Center
Rueve, Mary H.; Grate, John H.
This paper describes the methods used for revising the Cincinnati Mathematics Inventories, a battery of criterion-referenced tests of basic skills used in the Cincinnati Title III program and other city-wide special programs. Each of these tests is designed to cover a half-year of work; items are included to sample skills listed in the Catalog of…
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
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
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.…
ERIC Educational Resources Information Center
Cronin, John; Bowe, Branin
2004-01-01
Each year, Nevada students in grades 3, 4, 5, and 7 participate in testing as part of the Nevada assessment program. Students in grades 3 and 5 take the Nevada Criterion Referenced Assessment (Nevada CRT) while students in grades 4 and 7 take the Iowa Test of Basic Skills (ITBS). These tests serve as an important measure of student achievement for…
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…
Craig, Benjamin M; Ramachandran, Sulabha
2006-08-01
In a health state valuation study, respondents may be asked to rank a deck of cards, with each card representing a particular health state. A logical inconsistency occurs when a more severe health state card is ranked higher than a less severe card. Occasional inconsistencies may be justified by errors in judgment or measurement. However, when respondents return shuffled decks, their responses must be removed from the sample; otherwise, valuation estimates will be biased toward the median. In this paper, we present a logical consistency criterion for sample selection in health state valuation studies. This statistical criterion is based on the relative risk of a shuffled deck and generalizable to all health state classification systems, subsets (or decks) of health states, and valuation techniques. We applied the criterion to secondary data collected from 4048 United States and 3395 United Kingdom respondents. In both studies, respondents evaluated 12-card decks of EQ-5D health states using time trade-off and visual analog scale techniques. Among the UK respondents, a small portion (approximately 5%) did not satisfy the criterion; their exclusion significantly changed the sample characteristics and the mean value estimates of the EQ-5D health states. Similar results were found among the US respondents.
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…
Code of Federal Regulations, 2012 CFR
2012-01-01
... § 140.84 Criterion I—Substantial discharge of radioactive material or substantial radiation levels... radioactive material offsite, or that there have been substantial levels of radiation offsite, when, as a... facility and such contamination is characterized by levels of radiation in excess of one of the...
Code of Federal Regulations, 2011 CFR
2011-01-01
... § 140.84 Criterion I—Substantial discharge of radioactive material or substantial radiation levels... radioactive material offsite, or that there have been substantial levels of radiation offsite, when, as a... facility and such contamination is characterized by levels of radiation in excess of one of the...
Code of Federal Regulations, 2013 CFR
2013-01-01
... § 140.84 Criterion I—Substantial discharge of radioactive material or substantial radiation levels... radioactive material offsite, or that there have been substantial levels of radiation offsite, when, as a... facility and such contamination is characterized by levels of radiation in excess of one of the...
Code of Federal Regulations, 2014 CFR
2014-01-01
... § 140.84 Criterion I—Substantial discharge of radioactive material or substantial radiation levels... radioactive material offsite, or that there have been substantial levels of radiation offsite, when, as a... facility and such contamination is characterized by levels of radiation in excess of one of the...
ERIC Educational Resources Information Center
Esquivel, Juan M.; Quesada, Lilliana
The purpose of this study was to (1) develop and validate criterion-referenced tests to measure science knowledge of students who finished the fifth grade, as well as those who finished the three cycles of the General Education and (2) to assess the performance on these tests of a national, random sample of fourth-, sixth-, seventh-, and…
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
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…
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
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…
Catalano, S A; Goloboff, P A
2012-05-01
All methods proposed to date for mapping landmark configurations on a phylogenetic tree start from an alignment generated by methods that make no use of phylogenetic information, usually by superimposing all configurations against a consensus configuration. In order to properly interpret differences between landmark configurations along the tree as changes in shape, the metric chosen to define the ancestral assignments should also form the basis to superimpose the configurations. Thus, we present here a method that merges both steps, map and align, into a single procedure that (for the given tree) produces a multiple alignment and ancestral assignments such that the sum of the Euclidean distances between the corresponding landmarks along tree nodes is minimized. This approach is an extension of the method proposed by Catalano et al. (2010. Phylogenetic morphometrics (I): the use of landmark data in a phylogenetic framework. Cladistics. 26:539-549) for mapping landmark data with parsimony as optimality criterion. In the context of phylogenetics, this method allows maximizing the degree to which similarity in landmark positions can be accounted for by common ancestry. In the context of morphometrics, this approach guarantees (heuristics aside) that all the transformations inferred on the tree represent changes in shape. The performance of the method was evaluated on different data sets, indicating that the method produces marked improvements in tree score (up to 5% compared with generalized superimpositions, up to 11% compared with ordinary superimpositions). These empirical results stress the importance of incorporating the phylogenetic information into the alignment step. PMID:22213710
Dobolyi, David G; Dodson, Chad S
2013-12-01
Confidence judgments for eyewitness identifications play an integral role in determining guilt during legal proceedings. Past research has shown that confidence in positive identifications is strongly associated with accuracy. Using a standard lineup recognition paradigm, we investigated accuracy using signal detection and ROC analyses, along with the tendency to choose a face with both simultaneous and sequential lineups. We replicated past findings of reduced rates of choosing with sequential as compared to simultaneous lineups, but notably found an accuracy advantage in favor of simultaneous lineups. Moreover, our analysis of the confidence-accuracy relationship revealed two key findings. First, we observed a sequential mistaken identification overconfidence effect: despite an overall reduction in false alarms, confidence for false alarms that did occur was higher with sequential lineups than with simultaneous lineups, with no differences in confidence for correct identifications. This sequential mistaken identification overconfidence effect is an expected byproduct of the use of a more conservative identification criterion with sequential than with simultaneous lineups. Second, we found a steady drop in confidence for mistaken identifications (i.e., foil identifications and false alarms) from the first to the last face in sequential lineups, whereas confidence in and accuracy of correct identifications remained relatively stable. Overall, we observed that sequential lineups are both less accurate and produce higher confidence false identifications than do simultaneous lineups. Given the increasing prominence of sequential lineups in our legal system, our data argue for increased scrutiny and possibly a wholesale reevaluation of this lineup format.
Point defect generation, nano-void formation and growth. II. Criterion for ductile failure
NASA Astrophysics Data System (ADS)
Saimoto, S.; Diak, B. J.; Lloyd, D. J.
2012-05-01
Using the derived relation for point defect generation according to a new constitutive relation, the notion of nano-void formation at grown-in nano-particles is examined and its consequences deduced as the nano-voids grow in size with continued deformation. Assuming that void growth is due only to point defect accumulation, the analysis of fracture strains in tension of natural-aged AA6111 suggests that coalescence by micro-plastic activity occurs when the void diameter becomes about one third of the evolving inter-void spacing. Hence, the derived limit strain to incipient void-coalescence is inversely proportional to the square root of point defect generation as determined from the stress-strain data. Using this criterion, failure prediction maps can be constructed for strain modes of plane-strain and balanced bi-axial to result in the outer bounds of the forming limit diagram. Trial examinations with AA5754 and AA3003 show great promise.
Towards a Probabilistic Preliminary Design Criterion for Buckling Critical Composite Shells
NASA Technical Reports Server (NTRS)
Arbocz, Johann; Hilburger, Mark W.
2003-01-01
A probability-based analysis method for predicting buckling loads of compression-loaded laminated-composite shells is presented, and its potential as a basis for a new shell-stability design criterion is demonstrated and discussed. In particular, a database containing information about specimen geometry, material properties, and measured initial geometric imperfections for a selected group of laminated-composite cylindrical shells is used to calculate new buckling-load "knockdown factors". These knockdown factors are shown to be substantially improved, and hence much less conservative than the corresponding deterministic knockdown factors that are presently used by industry. The probability integral associated with the analysis is evaluated by using two methods; that is, by using the exact Monte Carlo method and by using an approximate First-Order Second- Moment method. A comparison of the results from these two methods indicates that the First-Order Second-Moment method yields results that are conservative for the shells considered. Furthermore, the results show that the improved, reliability-based knockdown factor presented always yields a safe estimate of the buckling load for the shells examined.
NASA Astrophysics Data System (ADS)
Zhou, Tao; Xie, Kai; Zhang, Junhao; Yang, Jie; He, Xiangjian
2015-05-01
It is a challenging task to develop an effective and robust object tracking method due to factors such as severe occlusion, background clutters, abrupt motion, illumination variation, and so on. A tracking algorithm based on weighted subspace reconstruction error is proposed. The discriminative weights are defined based on minimizing reconstruction error with a positive dictionary while maximizing reconstruction error with a negative dictionary. Then a confidence map for candidates is computed through the subspace reconstruction error. Finally, the location of the target object is estimated by maximizing the decision map which combines the discriminative weights and subspace reconstruction error. Furthermore, the new evaluation method based on a forward-backward tracking criterion is used to verify the proposed method and demonstrates its robustness in the updating stage and its effectiveness in the reduction of accumulated errors. Experimental results on 12 challenging video sequences show that the proposed algorithm performs favorably against 12 state-of-the-art methods in terms of accuracy and robustness.
Contaminant source reconstruction by empirical Bayes and Akaike's Bayesian Information Criterion
NASA Astrophysics Data System (ADS)
Zanini, Andrea; Woodbury, Allan D.
2016-02-01
The objective of the paper is to present an empirical Bayesian method combined with Akaike's Bayesian Information Criterion (ABIC) to estimate the contaminant release history of a source in groundwater starting from few concentration measurements in space and/or in time. From the Bayesian point of view, the ABIC considers prior information on the unknown function, such as the prior distribution (assumed Gaussian) and the covariance function. The unknown statistical quantities, such as the noise variance and the covariance function parameters, are computed through the process; moreover the method quantifies also the estimation error through the confidence intervals. The methodology was successfully tested on three test cases: the classic Skaggs and Kabala release function, three sharp releases (both cases regard the transport in a one-dimensional homogenous medium) and data collected from laboratory equipment that consists of a two-dimensional homogeneous unconfined aquifer. The performances of the method were tested with two different covariance functions (Gaussian and exponential) and also with large measurement error. The obtained results were discussed and compared to the geostatistical approach of Kitanidis (1995).
Alkhaldi, Weaam; Iskander, D Robert; Zoubir, Abdelhak M
2010-10-01
Corneal-height data are typically measured with videokeratoscopes and modeled using a set of orthogonal Zernike polynomials. We address the estimation of the number of Zernike polynomials, which is formalized as a model-order selection problem in linear regression. Classical information-theoretic criteria tend to overestimate the corneal surface due to the weakness of their penalty functions, while bootstrap-based techniques tend to underestimate the surface or require extensive processing. In this paper, we propose to use the efficient detection criterion (EDC), which has the same general form of information-theoretic-based criteria, as an alternative to estimating the optimal number of Zernike polynomials. We first show, via simulations, that the EDC outperforms a large number of information-theoretic criteria and resampling-based techniques. We then illustrate that using the EDC for real corneas results in models that are in closer agreement with clinical expectations and provides means for distinguishing normal corneal surfaces from astigmatic and keratoconic surfaces.
An examination of a group-velocity criterion for the breakdown of an idealized vortex flow
NASA Technical Reports Server (NTRS)
Tsai, C. Y.; Widnall, S. E.
1979-01-01
The phenomenon of vortex breakdown is believed to be associated with a finite amplitude wave that has become trapped at the critical or breakdown location. The conditions at which the propagating waves become trapped at a certain axial location were examined by use of a group-velocity criterion implied by Landahl's general theory of wave trapping. An ideal vortex having constant vorticity and uniform axial velocity at the inlet of a slowly diverging duct was studied. The linear wave propagation analysis is applied to the base flow at several axial stations for several values of the ratio of swirl velocity to axial velocity at the inlet of the divergent duct, assuming a locally parallel flow. The dipsersion relations and hence the group velocities of both the symmetric (n = 0) and asymmetric modes (n = + or - 1) were investigated. The existence of a critical state in the flow (at which the group velocity vanishes), and its relationship to the stagnation point on the axis of the duct and to the occurrence of an irregular singularity in the equations governing wave propagation in the flow field are discussed.
Responses of criterion variables to different supplemental doses of L-carnitine L-tartrate.
Spiering, Barry A; Kraemer, William J; Vingren, Jakob L; Hatfield, Disa L; Fragala, Maren S; Ho, Jen-Yu; Maresh, Carl M; Anderson, Jeffrey M; Volek, Jeff S
2007-02-01
L-carnitine L-tartrate (LCLT) supplementation beneficially affects markers of postexercise metabolic stress and muscle damage. However, to date, no study has determined the dose response of LCLT to elicit such responses. Therefore, the purpose of this study was to determine the effects of different doses of LCLT on criterion variables previously shown to be responsive to LCLT supplementation. Eight healthy men (22 +/- 3 y, 174 +/- 5 cm, 83.0 +/- 15.3 kg) were supplemented with 0 g, 1 g, and 2 g of LCLT for 3 weeks and then performed a bout of resistance exercise (5 sets of 15-20 repetition maximum with a 2-min rest between sets) with associated blood draws. This procedure was performed in a balanced, randomized, repeated measures design. Serum carnitine concentrations increased (p < or = 0.05) following the 1 g and 2 g doses, with the 2-g dose providing the highest carnitine concentrations. The 1- and 2-g doses reduced postexercise serum hypoxanthine, serum xanthine oxidase, serum myoglobin, and perceived muscle soreness. In conclusion, both the 1- and 2-g doses were effective in mediating various markers of metabolic stress and of muscle soreness. Use of LCLT appears to attenuate metabolic stress and the hypoxic chain of events leading to muscle damage after exercise.
Normal or reverse? The minimum angular deviation criterion of the classification
NASA Astrophysics Data System (ADS)
Man, O.
2003-04-01
Consider palaeomagnetic directions having been acquired for the purpose of magnetostratigraphy. They are to be classified into two groups, that of the normal and reverse polarity. In the case of great dispersion of directions this problem is not trivial and various methods of its solution are conceivable, including, e.g., those used for time series. The present poster suggests the way, how to classify the directions regardless the specimen position. Consider a set of n directions, say, n<18. They are included into directional statistics with either the original or changed polarity. For all of them except for the first one both possibilities are taken into account, the number of combinations being 2n-1. The mean direction and angular deviation are found for each combination and the optimum classification is given by that of minimum angular deviation. If a set includes a great number of directions the number of combinations would be too high. Therefore, the above optimum classification is found for its subset that has been set up by random choice. Any other direction is added to this subset with either original or changed polarity according to the same criterion. The technique is applied to the real magnetostratigraphic data. The research was supported by the GACR, No. 205/02/1576 and GAVR, No. A3013201.
NASA Astrophysics Data System (ADS)
Su, Xianli; Fu, Fan; Yan, Yonggao; Zheng, Gang; Liang, Tao; Zhang, Qiang; Cheng, Xin; Yang, Dongwang; Chi, Hang; Tang, Xinfeng; Zhang, Qingjie; Uher, Ctirad
2014-09-01
The existing methods of synthesis of thermoelectric (TE) materials remain constrained to multi-step processes that are time and energy intensive. Here we demonstrate that essentially all compound thermoelectrics can be synthesized in a single-phase form at a minimal cost and on the timescale of seconds using a combustion process called self-propagating high-temperature synthesis. We illustrate this method on Cu2Se and summarize key reaction parameters for other materials. We propose a new empirically based criterion for sustainability of the combustion reaction, where the adiabatic temperature that represents the maximum temperature to which the reacting compact is raised as the combustion wave passes through, must be high enough to melt the lower melting point component. Our work opens a new avenue for ultra-fast, low-cost, large-scale production of TE materials, and provides new insights into combustion process, which greatly broaden the scope of materials that can be successfully synthesized by this technique.
NASA Astrophysics Data System (ADS)
Zanini, A.; Woodbury, A. D.
2015-12-01
Contaminant release history identification has received considerable attention in the literature over the past several decades. In our review of this subject suggests that improvements are needed in terms of a reliable procedure, one that is easy to implement, with only few hyperparameters to estimate, and is able to evaluate confidence intervals. The purpose of this work is to propose an empirical Bayesian approach combined with the Akaike's Bayesian Information Criterion (ABIC) to estimate the contaminant release history starting from concentration observations in time or space. From the Bayesian point of view, the ABIC considers prior information on the unknown function, such as the prior distribution (assumed Gaussian) and the covariance function. The unknown statistical quantities, such as the noise variance and the covariance function parameters, are computed through the process; moreover the method also quantifies the estimation error through confidence intervals. We successfully test the method out on three test cases: the classic Skaggs and Kabala (1994) source, a "midnight dump" example that consists of three delta-like sources and lastly a laboratory dataset, consisting of two measurement points spatially but with synoptic observations. This experiment reproduces the response of a 2-D unconfined aquifer. The performance of the inverse method was tested with two different covariance functions (Gaussian and exponential) and also with large measurement error. Results show an excellent recovery of all sources used in the examples. Lastly, the obtained results were discussed and compared to the geostatistical approach of Kitanidis (1995).
Contaminant source reconstruction by empirical Bayes and Akaike's Bayesian Information Criterion.
Zanini, Andrea; Woodbury, Allan D
2016-01-01
The objective of the paper is to present an empirical Bayesian method combined with Akaike's Bayesian Information Criterion (ABIC) to estimate the contaminant release history of a source in groundwater starting from few concentration measurements in space and/or in time. From the Bayesian point of view, the ABIC considers prior information on the unknown function, such as the prior distribution (assumed Gaussian) and the covariance function. The unknown statistical quantities, such as the noise variance and the covariance function parameters, are computed through the process; moreover the method quantifies also the estimation error through the confidence intervals. The methodology was successfully tested on three test cases: the classic Skaggs and Kabala release function, three sharp releases (both cases regard the transport in a one-dimensional homogenous medium) and data collected from laboratory equipment that consists of a two-dimensional homogeneous unconfined aquifer. The performances of the method were tested with two different covariance functions (Gaussian and exponential) and also with large measurement error. The obtained results were discussed and compared to the geostatistical approach of Kitanidis (1995).
Su, Xianli; Fu, Fan; Yan, Yonggao; Zheng, Gang; Liang, Tao; Zhang, Qiang; Cheng, Xin; Yang, Dongwang; Chi, Hang; Tang, Xinfeng; Zhang, Qingjie; Uher, Ctirad
2014-01-01
The existing methods of synthesis of thermoelectric (TE) materials remain constrained to multi-step processes that are time and energy intensive. Here we demonstrate that essentially all compound thermoelectrics can be synthesized in a single-phase form at a minimal cost and on the timescale of seconds using a combustion process called self-propagating high-temperature synthesis. We illustrate this method on Cu2Se and summarize key reaction parameters for other materials. We propose a new empirically based criterion for sustainability of the combustion reaction, where the adiabatic temperature that represents the maximum temperature to which the reacting compact is raised as the combustion wave passes through, must be high enough to melt the lower melting point component. Our work opens a new avenue for ultra-fast, low-cost, large-scale production of TE materials, and provides new insights into combustion process, which greatly broaden the scope of materials that can be successfully synthesized by this technique. PMID:25223333