Identification of Mercier instabilities in Alcator C-Mod tokamak
In, Y.; Ramos, J. J.; Hastie, R. J.; Catto, P. J.; Hubbard, A. E.; Hutchinson, I. H.; Marmar, E.; Porkolab, M.; Snipes, J.; Wolfe, S.
2000-12-01
During current ramp-up discharges, highly localized magnetohydrodynamic (MHD) fluctuations were observed on the electron cyclotron emission diagnostics of Alcator C-Mod tokamak [I. H. Hutchinson , Phys. Plasmas 1, 1511 (1994)]. The electron temperature profile was hollow, while the density profile was weakly decreasing. Assuming that the equilibration time was short enough to quickly thermalize ions the pressure profile was also found to be hollow. Using this pressure profile as an additional constraint to the EFIT program, an equilibrium with reversed shear was constructed having a q(0)>>1. The localized MHD activity was observed near the inner q=5 rational surface in this reconstructed equilibrium, where the Mercier criterion for ideal MHD stability was violated because of the reversed pressure gradient (dp/dr>0), q>1 and moderate shear. When kinetic effects were added, the ideal Mercier mode was finite ion Larmor radius stabilized. However, ion Landau damping was found to be strong enough to drive a kinetic Mercier instability.
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.
The Distributed Criterion Design
ERIC Educational Resources Information Center
McDougall, Dennis
2006-01-01
This article describes and illustrates a novel form of the changing criterion design called the distributed criterion design, which represents perhaps the first advance in the changing criterion design in four decades. The distributed criterion design incorporates elements of the multiple baseline and A-B-A-B designs and is well suited to applied…
Unified tensile fracture criterion.
Zhang, Z F; Eckert, J
2005-03-11
We find that the classical failure criteria, i.e., maximum normal stress criterion, Tresca criterion, Mohr-Coulomb criterion, and von Mises criterion, cannot satisfactorily explain the tensile fracture behavior of the bulk metallic glass (BMG) materials. For a better description, we propose an ellipse criterion as a new failure criterion to unify the four classical criteria above and apply it to exemplarily describe the tensile fracture behavior of BMGs as well as a variety of other materials. It is suggested that each of the classical failure criteria can be unified by the present ellipse criterion depending on the difference of the ratio alpha=tau(0)/sigma(0).
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
2016-03-21
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.
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
An Empirical Kaiser Criterion.
Braeken, Johan; van Assen, Marcel A L M
2016-03-31
In exploratory factor analysis (EFA), most popular methods for dimensionality assessment such as the screeplot, the Kaiser criterion, or-the current gold standard-parallel analysis, are based on eigenvalues of the correlation matrix. To further understanding and development of factor retention methods, results on population and sample eigenvalue distributions are introduced based on random matrix theory and Monte Carlo simulations. These results are used to develop a new factor retention method, the Empirical Kaiser Criterion. The performance of the Empirical Kaiser Criterion and parallel analysis is examined in typical research settings, with multiple scales that are desired to be relatively short, but still reliable. Theoretical and simulation results illustrate that the new Empirical Kaiser Criterion performs as well as parallel analysis in typical research settings with uncorrelated scales, but much better when scales are both correlated and short. We conclude that the Empirical Kaiser Criterion is a powerful and promising factor retention method, because it is based on distribution theory of eigenvalues, shows good performance, is easily visualized and computed, and is useful for power analysis and sample size planning for EFA. (PsycINFO Database Record
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
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.
Designing Criterion-Referenced Assessment
ERIC Educational Resources Information Center
Burton, Kelley
2006-01-01
Criterion-referenced assessment arguably results in greater reliability, validity and transparency than norm-referenced assessment. This article examines this assertion with reference to an example from a second year undergraduate law unit at the Queensland University of Technology, LWB236 Real Property A. When designing criterion-referenced…
The correct kinetic Bohm criterion
NASA Astrophysics Data System (ADS)
Czarnetzki, Uwe; Tsankov, Tsanko Vaskov
2016-09-01
Space charge sheaths are characteristic for bounded plasmas and are a key element in plasma-surface interactions. Hence, one of the most fundamental concepts in plasma physics - the Bohm criterion - is related to the definition of a sheath edge. However, its kinetic formulation is stirring controversies for a long time - from questioning its validity at high collisionality to claiming a divergence in its formulation. Here, based on a solution of the Boltzmann equation for ions with charge-exchange collisions and ionization both of these disputes are resolved: 1) The obtained form of the kinetic Bohm criterion removes the divergence in the ionic part. 2) It also introduces a new equally important term that describes collisional and geometric effects. This new term reestablishes the validity of the criterion at high collisionality. 3) It also restores agreement with the fluid counterpart of the criterion. The developed theory is supported by non-invasive spatially resolved measurements and a numerical model.
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.
Developing Criterion-Referenced Programs.
ERIC Educational Resources Information Center
Read, Bruce H.
Criterion-referenced systems are founded on the belief that instruction should be based on the needs of individual pupils. If pupils' needs are to guide instruction, the system must identify the skills pupils need to learn and the sequence for their introduction. Additionally, there must be a way to identify the skills a pupil needs and those he…
Criterion Reading Instructional Project (CRIP).
ERIC Educational Resources Information Center
Linden Board of Education, NJ.
This booklet describes the Linden Title I Program between the years 1971-1974, with a focus on the Criterion Reading Instructional Project (CRIP). The program (in Linden, New Jersey) evolved from a supplemental reading and mathematics program to a structured developmental program of language arts designed to meet the needs of primary grade…
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…
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…
A universal criterion of melting.
Lubchenko, Vassiliy
2006-09-28
Melting is analyzed dynamically as a problem of localization at a liquid-solid interface. A Lindemann-like criterion of melting is derived in terms of particular vibrational amplitudes, which turn out to equal a universal quotient (about one-tenth) of the molecular spacing, at the interface. The near universality of the Lindemann ratio apparently arises owing to strongly overdamped dynamics near melting, and despite the anharmonic interactions being system-specific. A similar criterion is derived for structural displacements in the bulk of the solid, in particular the premelted layer; the criterion is no longer strictly universal, but still depends only on the harmonic properties of the solid. We further compute the dependence of the magnitude of the elemental molecular translations, in deeply supercooled fluids, on the temperature and the high frequency elastic constants. We show explicitly that the surface tension between distinct liquid states, near the glass transition of a supercooled liquid, is nearly evenly split between entropic and energetic contributions.
Formation Criterion for Synthetic Jets
2005-10-01
formation data for the axisymmetric case were published over 50 years ago by Ingard and Labate.10 More recent studies33,34 suggest that L0/d > 1 for...with the axisymmetric data from Ingard and Labate10 and Smith et al.33 are compared in Fig. 7. It is found that the available data are consis- tent with...the jet formation criterion with an empirically determined constant K equal to approximately 0.16. The deviation of Ingard and Labate’s data at their
Uncertainty Relation and Inseparability Criterion
NASA Astrophysics Data System (ADS)
Goswami, Ashutosh K.; Panigrahi, Prasanta K.
2017-02-01
We investigate the Peres-Horodecki positive partial transpose criterion in the context of conserved quantities and derive a condition of inseparability for a composite bipartite system depending only on the dimensions of its subsystems, which leads to a bi-linear entanglement witness for the two qubit system. A separability inequality using generalized Schrodinger-Robertson uncertainty relation taking suitable operators, has been derived, which proves to be stronger than the bi-linear entanglement witness operator. In the case of mixed density matrices, it identically distinguishes the separable and non separable Werner states.
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.
Separability criterion of tripartite qubit systems
Yu Changshui; Song Heshan
2005-08-15
In this paper, we present a method to construct full separability criterion for tripartite systems of qubits. The spirit of our approach is that a tripartite pure state can be regarded as a three-order tensor that provides an intuitionistic mathematical formulation for the full separability of pure states. We extend the definition to mixed states and give out the corresponding full separability criterion. As applications, we discuss the separability of several bound entangled states, which shows that our criterion is feasible.
Common Criterion For Failure Of Different Materials
NASA Technical Reports Server (NTRS)
Beyer, Rodney B.
1992-01-01
Common scaling criterion found to relate some physical quantities characterizing tensile failures of three different solid propellant materials. Tensile failures of different rubbery propellants characterized by similar plots.
On a criterion for vortex breakdown
NASA Technical Reports Server (NTRS)
Spall, R. E.; Gatski, T. B.; Grosch, C. H.
1987-01-01
A criterion for the onset of vortex breakdown is proposed. Based upon previous experimental, computational, and theoretical studies, an appropriately defined local Rossby number is used to delineate the region where breakdown occurs. In addition, new numerical results are presented which further validate this criterion. A number of previous theoretical studies concentrating on inviscid standing-wave analyses for trailing wing-tip vortices are reviewed and reinterpreted in terms of the Rossby number criterion. Consistent with previous studies, the physical basis for the onset of breakdown is identified as the ability of the flow to sustain such waves. Previous computational results are reviewed and re-evaluated in terms of the proposed breakdown criterion. As a result, the cause of breakdown occurring near the inflow computational boundary, common to several numerical studies, is identified. Finally, previous experimental studies of vortex breakdown for both leading edge and trailing wing-tip vortices are reviewed and quantified in terms of the Rossby number criterion.
An ethical criterion for geoscientists
NASA Astrophysics Data System (ADS)
Peppoloni, Silvia
2013-04-01
Anthropological researches have demonstrated that at some point in human history, man makes an evolutive jump in cultural sense: at first, he is able to perceive himself only as part of a community, later he becomes able to perceive himself as an individual. The analysis of the linguistic roots of the word "Ethics" discloses the traces of this evolutive transition and an original double meaning: on the one hand, "Ethics" contains a sense of belonging to the social fabric, on the other hand, it is related to the individual sphere. These two existential conditions (social and individual) unexpectedly co-exist in the word "Ethics". So, "Geo-Ethics" can be defined as the investigation and reflection on those values upon which to base appropriate behaviours and practices regarding the Geosphere (social dimension), but also as the analysis of the relationships between the geoscientist who acts and his own actions (individual dimension). Therefore, the meaning of the word "Geo-Ethics" calls upon geoscientists to face the responsibility of an ethical behaviour. What does this responsibility consist of and what motivations are necessary to push geoscientists to practice the Earth sciences in an ethical way? An ethical commitment exists if there is research of truth. In their activities, Geoscientists should be searchers and defenders of truth. If geoscientists give up this role, they completely empty of meaning their work. Ethical obligations arise from the possession of specific knowledge that has practical consequences. Geoscientists, as active and responsible part of society, have to serve society and the common good. The ethical criterion for a geoscientist should be rooted in his individual sphere, that is the source of any action even in the social sphere, and should have the intellectual honesty as main requirement. It includes: • respect for the truth that they look for and for other's ideas; • recognition of the value of others as valuable for themselves;
[The otherness as a criterion of bioethics].
Sadala, M L
1999-12-01
The present paper proposes questions about otherness as a fundamental criterion of Ethics and Bioethics, focusing on health care. The referencial mark used is the concept of otherness based on the Existencial Phenomenology.
The criterion of magnetism in semiconductor nanoobjects
NASA Astrophysics Data System (ADS)
Uspenskii, Yu. A.; Tikhonov, E. V.; Matsko, N. L.
2015-06-01
The Stoner criterion is known as a useful tool predicting the ferromagnetic state (FM) in metals. This criterion is not applied to nanoobjects, because of their discrete electron spectrum. In our paper we consider a generalization of this criterion, which can be applied to magnetism in semiconductor nanoobjects. To derive it, we compare total energies of the FM and non-magnetic states using many-body perturbation theory. The derived criterion has compact form and may be useful for prediction of ferromagnetism in nanoobjects. To check its precision, we performed first-principle calculations of several semiconductor nanoobjects in the FM and non-magnetic states and compared their results with predicted ones.
Griffith criterion for brittle fracture in graphene.
Yin, Hanqing; Qi, H Jerry; Fan, Feifei; Zhu, Ting; Wang, Baolin; Wei, Yujie
2015-03-11
There are prevailing concerns with the critical dimensions when conventional theories break down. Here we find that the Griffith criterion remains valid for cracks down to 10 nm but overestimates the strength of shorter cracks. We observe the preferred crack extension along the zigzag edge in graphene, and explain this phenomenon by local strength-based failure rather than energy-based Griffith criterion. These results provide a mechanistic basis for reliable applications of graphene in miniaturized devices and nanocomposites.
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.
Greedy Criterion in Orthogonal Greedy Learning.
Xu, Lin; Lin, Shaobo; Zeng, Jinshan; Liu, Xia; Fang, Yi; Xu, Zongben
2017-02-23
Orthogonal greedy learning (OGL) is a stepwise learning scheme that starts with selecting a new atom from a specified dictionary via the steepest gradient descent (SGD) and then builds the estimator through orthogonal projection. In this paper, we found that SGD is not the unique greedy criterion and introduced a new greedy criterion, called as ''δ-greedy threshold'' for learning. Based on this new greedy criterion, we derived a straightforward termination rule for OGL. Our theoretical study shows that the new learning scheme can achieve the existing (almost) optimal learning rate of OGL. Numerical experiments are also provided to support that this new scheme can achieve almost optimal generalization performance while requiring less computation than OGL.
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.…
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.
A Criterion-Referenced Test for Archery.
ERIC Educational Resources Information Center
Shifflett, Bethany; Schuman, Barbara J.
1982-01-01
A criterion-referenced test for a beginning archery class was developed and evaluated. Techniques for estimating test validity and reliability were applied to data. A method developed by R. A. Burk (1976) was used to establish a cutoff score that would distinguish between those mastering the class and nonmasters. (Authors/PP)
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…
POSTTRAINING PERFORMANCE CRITERION DEVELOPMENT AND APPLICATION.
ERIC Educational Resources Information Center
SIEGEL, ARTHUR I.
IN THIS SUMMARY OF 22 RESEARCH REPORTS, THE DEVELOPMENT AND APPLICATION OF CRITERION INSTRUMENTS TO ASSESS THE TECHNICAL PROFICIENCY OF U.S. NAVY AERONAUTICAL SUPPORT PERSONNEL ARE DISCUSSED. THE STUDIES, SUMMARIZED IN TERMS OF THE CHRONOLOGICAL AND LOGICAL INTERRELATIONSHIPS INVOLVED, DEAL WITH PRELIMINARY AND FINAL FORMS OF TECHNICAL BEHAVIOR…
The gradient deformation criterion for brittle fracture
NASA Astrophysics Data System (ADS)
Kuliev, V. D.; Morozov, E. M.
2016-10-01
A new fracture criterion based on the assumption that brittle fracture occurs when the strain gradient reaches its limiting value is formulated. The presence of a strain gradient at the boundary of a body's temperature drop is shown analytically. The results of an experiment with specimens under an abrupt change in temperature are presented.
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…
Generalized sheath criterion for arbitrary degenerate plasmas
NASA Astrophysics Data System (ADS)
Akbari-Moghanjoughi, M.
2017-01-01
In this research, we study the generalized sheath criterion for plasmas with an arbitrary degree of electron degeneracy and temperature, ranging from the classical dilute regime to the fully degenerate quantum plasmas. The latter may be relevant to warm dense matter and/or laboratory high energy density matter or even astrophysical stellar plasmas. The hydrostatic one dimensional model is used to establish the generalized Bohm's criterion for sheath entrance ion speed limits, and the small amplitude theory of the sheath problem, which accurately describes the sheath parameters for lower ion acoustic Mach numbers, is developed. Our results indicate that the sheath characteristic parameters such as electrostatic potential and density profiles, as well as the wall potential and the sheath length, are significantly affected by plasma parameters such as the ion and electron temperature and number densities in the plasma region. In particular, there are fundamental differences between sheath structures of the dilute classical plasmas and those of dense quantum ones.
Existence criterion of genuine tripartite entanglement
Yu Changshui; Song Heshan
2006-03-15
In this paper, an intuitive mathematical formulation is provided to generalize the residual entanglement for tripartite systems of qubits [Phys. Rev. A 61, 052306 (2000)] to the tripartite systems in higher dimension. The spirit lies in the tensor treatment of tripartite pure states [Phys. Rev. A 72, 022333 (2005)]. A distinct characteristic of the present generalization is that the formulation for higher dimensional systems is invariant under permutation of the subsystems, hence is employed as a criterion to test the existence of genuine tripartite entanglement. Furthermore, the formulation for pure states can be conveniently extended to the case of mixed states by utilizing the Kronecker product approximate technique. As applications, we give the analytic approximation of the criterion for weakly mixed tripartite quantum states and consider the existence of genuine tripartite entanglement of some weakly mixed states.
Contemporary Views on Criterion-Referenced Testing
1979-10-01
slightly different area of application, Knipe (1973) sumarized the Grand Forks Learning System in which CRTs played a salient part. The Grand Forks School ...Knipe concluded: "The criterion-referenced test is the only Contemporary Views 54 type of test that a school district can use to determine if it is...mathematics and science curriculum for the elementary school ’ (6) "National Assessment of Educational Progress", CRTs designed to assess student.achievement
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…
Blind equalization with criterion with memory nonlinearity
NASA Astrophysics Data System (ADS)
Chen, Yuanjie; Nikias, Chrysostomos L.; Proakis, John G.
1992-06-01
Blind equalization methods usually combat the linear distortion caused by a nonideal channel via a transversal filter, without resorting to the a priori known training sequences. We introduce a new criterion with memory nonlinearity (CRIMNO) for the blind equalization problem. The basic idea of this criterion is to augment the Godard [or constant modulus algorithm (CMA)] cost function with additional terms that penalize the autocorrelations of the equalizer outputs. Several variations of the CRIMNO algorithms are derived, with the variations dependent on (1) whether the empirical averages or the single point estimates are used to approximate the expectations, (2) whether the recent or the delayed equalizer coefficients are used, and (3) whether the weights applied to the autocorrelation terms are fixed or are allowed to adapt. Simulation experiments show that the CRIMNO algorithm, and especially its adaptive weight version, exhibits faster convergence speed than the Godard (or CMA) algorithm. Extensions of the CRIMNO criterion to accommodate the case of correlated inputs to the channel are also presented.
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.
Social influences on adaptive criterion learning.
Cassidy, Brittany S; Dubé, Chad; Gutchess, Angela H
2015-07-01
People adaptively shift decision criteria when given biased feedback encouraging specific types of errors. Given that work on this topic has been conducted in nonsocial contexts, we extended the literature by examining adaptive criterion learning in both social and nonsocial contexts. Specifically, we compared potential differences in criterion shifting given performance feedback from social sources varying in reliability and from a nonsocial source. Participants became lax when given false positive feedback for false alarms, and became conservative when given false positive feedback for misses, replicating prior work. In terms of a social influence on adaptive criterion learning, people became more lax in response style over time if feedback was provided by a nonsocial source or by a social source meant to be perceived as unreliable and low-achieving. In contrast, people adopted a more conservative response style over time if performance feedback came from a high-achieving and reliable source. Awareness that a reliable and high-achieving person had not provided their feedback reduced the tendency to become more conservative, relative to those unaware of the source manipulation. Because teaching and learning often occur in a social context, these findings may have important implications for many scenarios in which people fine-tune their behaviors, given cues from others.
Regularization Parameter Selections via Generalized Information Criterion
Zhang, Yiyun; Li, Runze; Tsai, Chih-Ling
2009-01-01
We apply the nonconcave penalized likelihood approach to obtain variable selections as well as shrinkage estimators. This approach relies heavily on the choice of regularization parameter, which controls the model complexity. In this paper, we propose employing the generalized information criterion (GIC), encompassing the commonly used Akaike information criterion (AIC) and Bayesian information criterion (BIC), for selecting the regularization parameter. Our proposal makes a connection between the classical variable selection criteria and the regularization parameter selections for the nonconcave penalized likelihood approaches. We show that the BIC-type selector enables identification of the true model consistently, and the resulting estimator possesses the oracle property in the terminology of Fan and Li (2001). In contrast, however, the AIC-type selector tends to overfit with positive probability. We further show that the AIC-type selector is asymptotically loss efficient, while the BIC-type selector is not. Our simulation results confirm these theoretical findings, and an empirical example is presented. Some technical proofs are given in the online supplementary material. PMID:20676354
On the hodological criterion for homology
Faunes, Macarena; Francisco Botelho, João; Ahumada Galleguillos, Patricio; Mpodozis, Jorge
2015-01-01
Owen's pre-evolutionary definition of a homolog as “the same organ in different animals under every variety of form and function” and its redefinition after Darwin as “the same trait in different lineages due to common ancestry” entail the same heuristic problem: how to establish “sameness.”Although different criteria for homology often conflict, there is currently a generalized acceptance of gene expression as the best criterion. This gene-centered view of homology results from a reductionist and preformationist concept of living beings. Here, we adopt an alternative organismic-epigenetic viewpoint, and conceive living beings as systems whose identity is given by the dynamic interactions between their components at their multiple levels of composition. We posit that there cannot be an absolute homology criterion, and instead, homology should be inferred from comparisons at the levels and developmental stages where the delimitation of the compared trait lies. In this line, we argue that neural connectivity, i.e., the hodological criterion, should prevail in the determination of homologies between brain supra-cellular structures, such as the vertebrate pallium. PMID:26157357
On the definition of a criterion of immunogenicity.
Pradeu, Thomas; Carosella, Edgardo D
2006-11-21
The main objective of immunology is to establish why and when an immune response occurs, that is, to determine a criterion of immunogenicity. According to the consensus view, the proper criterion of immunogenicity lies in the discrimination between self and nonself. Here we challenge this consensus by suggesting a simpler and more comprehensive criterion, the criterion of continuity. Moreover, we show that this criterion may be considered as an interpretation of the immune "self." We conclude that immunologists can continue to speak of the self, provided that they admit that the self/nonself discrimination is not an adequate criterion of immunogenicity.
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
2015-08-06
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).
A criterion autoscheduler for long range planning
NASA Technical Reports Server (NTRS)
Sponsler, Jeffrey L.
1994-01-01
A constraint-based scheduling system called SPIKE is used to create long-term schedules for the Hubble Space Telescope. A meta-level scheduler called the Criterion Autoscheduler for Long range planning (CASL) was created to guide SPIKE's schedule generation according to the agenda of the planning scientists. It is proposed that sufficient flexibility exists in a schedule to allow high level planning heuristics to be applied without adversely affected crucial constraints such as spacecraft efficiency. This hypothesis is supported by test data which is described.
Generalized Bohm Criterion for Electronegative Complex Plasma
Chekour, S.; Tahraoui, A.
2011-11-29
In this work, we have generalized the computation of Bohm criterion for electronegative complex plasma. For this, we have established a one-dimensional, unmagnetized and stationary theoretical model where the positive ions and dust particles are modeled by fluid equations. The electrons and negative ions are considered in thermodynamic equilibrium; therefore they obey to Boltzmann's statistic. In this case, the numerical results show that the generalized Bohm velocity is small compared to the classical value. For electronegative dusty plasma, the corrections are less important.
Criterion-Referenced Testing in Foreign Language Teaching.
ERIC Educational Resources Information Center
Takala, Sauli
A review of literature serves as the basis for a discussion of various aspects of criterion-referenced tests. The aspects discussed are: teaching and evaluation objectives, criterion- and norm-referenced measurement, stages in construction of criterion-referenced tests, construction and selection of items, test validity, and test reliability.…
Extensions and applications of the Bohm criterion
NASA Astrophysics Data System (ADS)
Baalrud, Scott D.; Scheiner, Brett; Yee, Benjamin; Hopkins, Matthew; Barnat, Edward
2015-04-01
The generalized Bohm criterion is revisited in the context of incorporating kinetic effects of the electron and ion distribution functions into the theory. The underlying assumptions and results of two different approaches are compared: the conventional ‘kinetic Bohm criterion’ and a fluid-moment hierarchy approach. The former is based on the asymptotic limit of an infinitely thin sheath (λD/l = 0), whereas the latter is based on a perturbative expansion of a sheath that is thin compared to the plasma (λD/l ≪ 1). Here λD is the Debye length, which characterizes the sheath length scale, and l is a measure of the plasma or presheath length scale. The consequences of these assumptions are discussed in terms of how they restrict the class of distribution functions to which the resulting criteria can be applied. Two examples are considered to provide concrete comparisons between the two approaches. The first is a Tonks-Langmuir model including a warm ion source (Robertson 2009 Phys. Plasmas 16 103503). This highlights a substantial difference between the conventional kinetic theory, which predicts slow ions dominate at the sheath edge, and the fluid moment approach, which predicts slow ions have little influence. The second example considers planar electrostatic probes biased near the plasma potential using model equations and particle-in-cell simulations. This demonstrates a situation where electron kinetic effects alter the Bohm criterion, leading to a subsonic ion flow at the sheath edge.
Kinematic criterion for breaking of shoaling waves
NASA Astrophysics Data System (ADS)
Liberzon, Dan; Itay, Uri
2016-11-01
Validity of a kinematic criterion for breaking of shoaling waves was examined experimentally. Results obtained by simultaneous measurements of water surface velocity by PTV and of the propagation velocity of a steep crest up to the point of breaking inception during shoaling will be reported. The experiments performed in a large wave tank examining breaking behavior of gentle spillers during shoaling on three different slopes suggest a validity of the recently proposed kinematic criterion. The breaking inception was found to occur when the horizontal velocity of the water surface on the steep (local steepness of 0.41-0.6) crest reaches a threshold value of 0.85-0.95 of that of the crest propagation. The exact moment and position of breaking inception detected using a Phase Time Method (PTM), characterizing a unique shape of the local frequency fluctuations at the inception. Future implementation of the PTM method for detection of breaking events in irregular wave fields will be discussed. Supported by German-Israeli Foundation for Scientific Research and Development (GIF) Grant #2019392.
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 proposed criterion for aircraft flight in turbulence
NASA Technical Reports Server (NTRS)
Porter, R. F.; Robinson, A. C.
1971-01-01
A proposed criterion for aircraft flight in turbulent conditions is presented. Subjects discussed are: (1) the problem of flight safety in turbulence, (2) new criterion for turbulence flight where existing ones seem adequate, and (3) computational problems associated with new criterion. Primary emphasis is placed on catastrophic occurrences in subsonic cruise with the aircraft under automatic control. A Monte Carlo simulation is used in the formulation and evaluation of probabilities of survival of an encounter with turbulence.
An Independent and Coordinated Criterion for Kinematic Aircraft Maneuvers
NASA Technical Reports Server (NTRS)
Narkawicz, Anthony J.; Munoz, Cesar A.; Hagen, George
2014-01-01
This paper proposes a mathematical definition of an aircraft-separation criterion for kinematic-based horizontal maneuvers. It has been formally proved that kinematic maneu- vers that satisfy the new criterion are independent and coordinated for repulsiveness, i.e., the distance at closest point of approach increases whether one or both aircraft maneuver according to the criterion. The proposed criterion is currently used in NASA's Airborne Coordinated Resolution and Detection (ACCoRD) set of tools for the design and analysis of separation assurance systems.
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.
Suboptimal Criterion Learning in Static and Dynamic Environments
Fleming, Stephen M.; Daw, Nathaniel D.
2017-01-01
Humans often make decisions based on uncertain sensory information. Signal detection theory (SDT) describes detection and discrimination decisions as a comparison of stimulus “strength” to a fixed decision criterion. However, recent research suggests that current responses depend on the recent history of stimuli and previous responses, suggesting that the decision criterion is updated trial-by-trial. The mechanisms underpinning criterion setting remain unknown. Here, we examine how observers learn to set a decision criterion in an orientation-discrimination task under both static and dynamic conditions. To investigate mechanisms underlying trial-by-trial criterion placement, we introduce a novel task in which participants explicitly set the criterion, and compare it to a more traditional discrimination task, allowing us to model this explicit indication of criterion dynamics. In each task, stimuli were ellipses with principal orientations drawn from two categories: Gaussian distributions with different means and equal variance. In the covert-criterion task, observers categorized a displayed ellipse. In the overt-criterion task, observers adjusted the orientation of a line that served as the discrimination criterion for a subsequently presented ellipse. We compared performance to the ideal Bayesian learner and several suboptimal models that varied in both computational and memory demands. Under static and dynamic conditions, we found that, in both tasks, observers used suboptimal learning rules. In most conditions, a model in which the recent history of past samples determines a belief about category means fit the data best for most observers and on average. Our results reveal dynamic adjustment of discrimination criterion, even after prolonged training, and indicate how decision criteria are updated over time. PMID:28046006
A Difference Criterion for Dimensionality Reduction
NASA Astrophysics Data System (ADS)
Aved, A. J.; Blasch, E.; Peng, J.
2015-12-01
A dynamic data-driven geoscience application includes hyperspectral scene classification which has shown promising potential in many remote-sensing applications. A hyperspectral image of a scene spectral radiance is typically measured by hundreds of contiguous spectral bands or features, ranging from visible/near-infrared (VNIR) to shortwave infrared (SWIR). Spectral-reflectance measurements provide rich information for object detection and classification. On the other hand, they generate a large number of features, resulting in a high dimensional measurement space. However, a large number of features often poses challenges and can result in poor classification performance. This is due to the curse of dimensionality which requires model reduction, uncertainty quantification and optimization for real-world applications. In such situations, feature extraction or selection methods play an important role by significantly reducing the number of features for building classifiers. In this work, we focus on efficient feature extraction using the dynamic data-driven applications systems (DDDAS) paradigm. Many dimension reduction techniques have been proposed in the literature. A well-known technique is Fisher's linear discriminant analysis (LDA). LDA finds the projection matrix that simultaneously maximizes a within class scatter matrix and minimizes a between class scatter matrix. However, LDA requires matrix inverse which can be a major issue when the within matrix is singular. We propose a difference criterion for dimension reduction that does not require a matrix inverse for software implementation. We show how to solve the optimization problem with semi-definite programming. In addition, we establish an error bound for the proposed algorithm. We demonstrate the connection between relief feature selection and a two class formulation of multi-class problems, thereby providing a sound basis for observed benefits associated with this formulation. Finally, we provide
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 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…
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…
A System for Describing and Evaluating Criterion-Referenced Tests.
ERIC Educational Resources Information Center
Kosecoff, Jacqueline; And Others
There are, at present, a number of tests that are labeled criterion referenced. These tests vary considerably in format, design, analysis, and function. In order to provide an efficient and objective procedure for describing, assessing, and comparing these measures, the Criterion Referenced Test Description and Evaluation (CRTDE) rating system was…
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…
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…
An Optimal Design Approach to Criterion-Referenced Computerized Testing
ERIC Educational Resources Information Center
Wiberg, Marie
2003-01-01
A criterion-referenced computerized test is expressed as a statistical hypothesis problem. This admits that it can be studied by using the theory of optimal design. The power function of the statistical test is used as a criterion function when designing the test. A formal proof is provided showing that all items should have the same item…
A shear ductile fracture criterion for metal forming
NASA Astrophysics Data System (ADS)
Lou, Yanshan; Yoon, Jeong Whan
2016-08-01
In this paper, an uncoupled shear ductile fracture criterion is developed for prediction of ductile fracture in sheet metal forming from shear to balanced biaxial tension. The ductile fracture criterion is calibrated by four tests of sheet metal: shear tests, uniaxial tension, plane strain tension and the Nakajima test. Specimens are designed for AA6082 T6 (t1.0) for the calibration of the proposed ductile fracture criterion. The calibrated ductile fracture criterion is then implemented into numerical simulation for the prediction of ductile fracture of the aluminum alloy. For the purpose of comparison, onset of ductile fracture is also estimated by MMC3, DF2012 and DF2014 criteria. The comparison indicates that the developed criterion can accurately predict onset of ductile fracture for all four loading conditions, but the other three criteria can only provide reasonable prediction for three tests. Accordingly, the newly developed ductile fracture criterion is suggested to be used in prediction of ductile fracture for sheet metal forming in wide loading condition from shear to the balanced biaxial tension. Discussion on calibration of this ductile fracture criterion also indicates that the ductile fracture criterion can be employed in estimation of ductile fracture for bulk metal forming processes with better predictability.
The Instructional Consequences of Criterion-Referenced Clarity.
ERIC Educational Resources Information Center
Popham, W. James
1994-01-01
The instructional impact of criterion-referenced testing during the past three decades is reviewed, and a method of devising criterion-referenced tests is suggested that departs from the usual model. Adding verification along the lines of panel review that newly constructed test items do elicit appropriate information is suggested. (SLD)
Failure Criterion for Brick Masonry: A Micro-Mechanics Approach
NASA Astrophysics Data System (ADS)
Kawa, Marek
2015-02-01
The paper deals with the formulation of failure criterion for an in-plane loaded masonry. Using micro-mechanics approach the strength estimation for masonry microstructure with constituents obeying the Drucker-Prager criterion is determined numerically. The procedure invokes lower bound analysis: for assumed stress fields constructed within masonry periodic cell critical load is obtained as a solution of constrained optimization problem. The analysis is carried out for many different loading conditions at different orientations of bed joints. The performance of the approach is verified against solutions obtained for corresponding layered and block microstructures, which provides the upper and lower strength bounds for masonry microstructure, respectively. Subsequently, a phenomenological anisotropic strength criterion for masonry microstructure is proposed. The criterion has a form of conjunction of Jaeger critical plane condition and Tsai-Wu criterion. The model proposed is identified based on the fitting of numerical results obtained from the microstructural analysis. Identified criterion is then verified against results obtained for different loading orientations. It appears that strength of masonry microstructure can be satisfactorily described by the criterion proposed.
Does the World Health Organization criterion adequately define glaucoma blindness?
Mokhles, P; Schouten, JSAG; Beckers, HJM; Webers, CAB
2017-01-01
Purpose Blindness in glaucoma is difficult to assess with merely the use of the current World Health Organization (WHO) definition (a visual field restricted to 10° in a radius around central fixation), as this criterion does not cover other types of visual field loss that are encountered in clinical practice and also depict blindness. In this study, a 5-point ordinal scale was developed for the assessment of common visual field defect patterns, with the purpose of comparing blindness as outcome to the findings with the WHO criterion when applied to the same visual fields. The scores with the two methods were compared between two ophthalmologists. In addition, the variability between these assessors in assessing the different visual field types was determined. Methods Two glaucoma specialists randomly assessed a sample of 423 visual fields from 77 glaucoma patients, stripped of all indices and masked for all patient variables. They applied the WHO criterion and a 5-point ordinal scale to all visual fields for the probability of blindness. Results The WHO criterion was mostly found applicable and in good agreement for both assessors to visual fields depicting central island of vision or a temporal crescent. The percentage of blindness scores was higher when using the ordinal scale, 21.7% and 19.6% for assessors A and B, respectively, versus 14.4% and 11.3% for the WHO criterion. However, Kappa was lower, 0.71 versus 0.78 for WHO. Conclusions The WHO criterion is strictly applied and shows good agreement between assessors; however, blindness does not always fit this criterion. More visual fields are labeled as blind when a less stringent criterion is used, but this leads to more interobserver variability. A new criterion that describes the extent, location, and depth of visual field defects together with their consequence for the patient’s quality of life is needed for the classification of glaucoma blindness. PMID:28280297
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.
Multi-criterion optimization for heel-toe running.
Wang, Nenzi
2005-08-01
This paper presents an optimization procedure for multi-criterion analysis essential in many biomechanical studies. The optimization is illustrated with a heel-toe running analysis wherein the rate of load and the passive load on support leg are minimized concurrently. The goal of multi-criterion optimization is achieved by incorporating the criterion of Pareto optimality in the genetic algorithm. The proposed procedure can replace the popular weighted-sum approach for problems with multiple objectives. The selection of a final design from the Pareto optimum points (non-dominated designs) can be determined, based on the min-max objective deviation criterion. Nevertheless, a different decision can be made in the final selection without incurring recalculations. The scheme is readily adoptable for parallel computing, which deserves further study to reduce the execution time in a complex biomechanical analysis.
Two Approaches to Criterion-Referenced Program Assessment.
ERIC Educational Resources Information Center
Haladyna, Tom
1982-01-01
Describes two types of criterion-referenced testing that districts can use to measure achievement outcomes of their instructional programs: a random sampling assessment plan and an item-response theory assessment plan. (Author/JM)
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)
Evaluation of the tensor polynomial failure criterion for composite materials
NASA Technical Reports Server (NTRS)
Tennyson, R. C.; Macdonald, D.; Nanyaro, A. P.
1978-01-01
A comprehensive experimental and analytical evaluation of the tensor polynomial failure criterion was undertaken to determine its capability for predicting the ultimate strength of laminated composite structures subject to a plane stress state. Results are presented demonstrating that a quadratic formulation is too conservative and a cubic representation is required. Strength comparisons with test data derived from glass/epoxy and graphite/epoxy tubular specimens are also provided to validate the cubic strength criterion.
Criterion buys Akzo`s naphtha reforming catalysts business
Rotman, D.
1993-12-08
In a move that further consolidates the refinery catalysts market, Criterion Catalyst (Houston) has bought Akzo`s reforming business for an undisclosed price. The acquisition gives Criterion-a joint venture between Shell and American Cyanamid-roughly 35% of the $50-million/year worldwide reforming market. Akzo says it is quitting the business to focus on larger refinery catalysts applications in hydroprocessing and fluid cracking catalysts.
An approximate spin design criterion for monoplanes, 1 May 1939
NASA Technical Reports Server (NTRS)
Seidman, O.; Donlan, C. J.
1976-01-01
An approximate empirical criterion, based on the projected side area and the mass distribution of the airplane, was formulated. The British results were analyzed and applied to American designs. A simpler design criterion, based solely on the type and the dimensions of the tail, was developed; it is useful in a rapid estimation of whether a new design is likely to comply with the minimum requirements for safety in spinning.
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.
An improved failure criterion for biological and engineered staggered composites.
Barthelat, Francois; Dastjerdi, Ahmad Khayer; Rabiei, Reza
2013-02-01
High-performance biological materials such as nacre, spider silk or bone have evolved a staggered microstructure consisting of stiff and strong elongated inclusions aligned with the direction of loading. This structure leads to useful combinations of stiffness, strength and toughness, and it is therefore increasingly mimicked in bio-inspired composites. The performance of staggered composites can be tuned; for example, their mechanical properties increase when the overlap between the inclusions is increased. However, larger overlaps may lead to excessive tensile stress and fracture of the inclusions themselves, a highly detrimental failure mode. Fracture of the inclusions has so far only been predicted using highly simplified models, which hinder our ability to properly design and optimize engineered staggered composites. In this work, we develop a new failure criterion that takes into account the complex stress field within the inclusions as well as initial defects. The model leads to an 'optimum criterion' for cases where the shear tractions on the inclusions is uniform, and a 'conservative' criterion for which the tractions are modelled as point forces at the ends of the overlap regions. The criterion can therefore be applied for a wide array of material behaviour at the interface, even if the details of the shear load transfer is not known. The new criterion is validated with experiments on staggered structures made of millimetre-thick alumina tablets, and by comparison with data on nacre. Formulated in a non-dimensional form, our new criterion can be applied on a wide variety of engineered staggered composites at any length scale. It also reveals new design guidelines, for example high aspect ratio inclusions with weak interfaces are preferable over inclusions with low aspect ratio and stronger interfaces. Together with existing models, this new criterion will lead to optimal designs that harness the full potential of bio-inspired staggered composites.
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.
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.
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.
Robust Criterion for the Existence of Nonhyperbolic Ergodic Measures
NASA Astrophysics Data System (ADS)
Bochi, Jairo; Bonatti, Christian; Díaz, Lorenzo J.
2016-06-01
We give explicit C 1-open conditions that ensure that a diffeomorphism possesses a nonhyperbolic ergodic measure with positive entropy. Actually, our criterion provides the existence of a partially hyperbolic compact set with one-dimensional center and positive topological entropy on which the center Lyapunov exponent vanishes uniformly. The conditions of the criterion are met on a C 1-dense and open subset of the set of diffeomorphisms having a robust cycle. As a corollary, there exists a C 1-open and dense subset of the set of non-Anosov robustly transitive diffeomorphisms consisting of systems with nonhyperbolic ergodic measures with positive entropy. The criterion is based on a notion of a blender defined dynamically in terms of strict invariance of a family of discs.
Criticality and quenched disorder: Harris criterion versus rare regions.
Vojta, Thomas; Hoyos, José A
2014-02-21
We employ scaling arguments and optimal fluctuation theory to establish a general relation between quantum Griffiths singularities and the Harris criterion for quantum phase transitions in disordered systems. If a clean critical point violates the Harris criterion, it is destabilized by weak disorder. At the same time, the Griffiths dynamical exponent z' diverges upon approaching the transition, suggesting unconventional critical behavior. In contrast, if the Harris criterion is fulfilled, power-law Griffiths singularities can coexist with clean critical behavior, but z' saturates at a finite value. We present applications of our theory to a variety of systems including quantum spin chains, classical reaction-diffusion systems and metallic magnets, and we discuss modifications for transitions above the upper critical dimension. Based on these results we propose a unified classification of phase transitions in disordered systems.
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.
Judging Criterion of Controlled Structures with Closely Spaced Natural Frequencies
Xie Faxiang; Sun Limin
2010-05-21
The structures with closely spaced natural frequencies widely exist in civil engineering; however, the judging criterion of the density of closely spaced frequencies is in dispute. This paper suggests a judging criterion for structures with closely spaced natural frequencies based on the analysis on a controlled 2-DOF structure. The analysis results indicate that the optimal control gain of the structure with velocity feedback is dependent on the frequency density parameter of structure and the maximum attainable additional modal damping ratio is 1.72 times of the frequency density parameter when state feedback is applied. Based on a brief review on the previous researches, a judging criterion related the minimum frequency density parameter and the required mode damping ratio was proposed.
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.
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.
Pauli criterion and the vector Aharonov{endash}Bohm effect
Li, C.
1996-12-01
After discussing the commutation relations of the kinetic angular momentum of the electron in the vector Aharonov{endash}Bohm effect, the author shows that the Pauli criterion for admissibility of the wave function is inapplicable. The point is that the kinetic angular momentum does not satisfy the fundamental commutation relations of the angular momentum. The inapplicability of the Pauli criterion reflects the breakdown of the symmetry of the electron{close_quote}s motion around the solenoid. Copyright {copyright} 1996 Academic Press, Inc.
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…
Creativity.4in1: Four-Criterion Construct of Creativity
ERIC Educational Resources Information Center
Kharkhurin, Anatoliy V.
2014-01-01
The purpose of this theoretical article is to provide an extended definition of creativity that embraces potential cross-cultural variations in this construct. Creativity is defined as a 4-criterion construct, which includes attributes of novelty, utility, aesthetics, and authenticity. Novelty attribute stipulates that a creative work brings…
The 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…
Using Statistical Penalties In The Tsai-Wu Failure Criterion
NASA Technical Reports Server (NTRS)
Richardson, D. E.; Regl, R. R.; Iverson, M. P.; Phipps, B. E.
1996-01-01
Improved methods of applying statistical penalties when using Tsai-Wu failure criterion lead to more accurate predictions of failures of composite-material structural components under stress, and provide better safety factors for designing such components. Intended to ensure proper use of statistical penalties with respect to failure hypersurface.
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…
Criteria to Evaluate Interpretive Guides for Criterion-Referenced Tests
ERIC Educational Resources Information Center
Trapp, William J.
2007-01-01
This project provides a list of criteria for which the contents of interpretive guides written for customized, criterion-referenced tests can be evaluated. The criteria are based on the "Standards for Educational and Psychological Testing" (1999) and examine the content breadth of interpretive guides. Interpretive guides written for…
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…
Signal Detection with Criterion Noise: Applications to Recognition Memory
ERIC Educational Resources Information Center
Benjamin, Aaron S.; Diaz, Michael; Wee, Serena
2009-01-01
A tacit but fundamental assumption of the theory of signal detection is that criterion placement is a noise-free process. This article challenges that assumption on theoretical and empirical grounds and presents the noisy decision theory of signal detection (ND-TSD). Generalized equations for the isosensitivity function and for measures of…
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…
Orthogonality criterion for banishing hydrino states from standard quantum mechanics
NASA Astrophysics Data System (ADS)
de Castro, Antonio S.
2007-10-01
Orthogonality criterion is used to shown in a very simple and general way that anomalous bound-state solutions for the Coulomb potential (hydrino states) do not exist as bona fide solutions of the Schr\\"{o}dinger, Klein-Gordon and Dirac equations.
Does the Bohm Criterion have meaning for collisional plasmas?
NASA Astrophysics Data System (ADS)
Severn, Greg; Yip, Chi-Shung; Nourgostar, Sirous; Hershkowitz, Noah
2014-10-01
Theorists view the Bohm criterion as approximately true, holding only for collisionless plasmas. The question of whether there exists a collisionally modified Bohm Criterion (CMBC) is often answered in the negative, and it is only a question of how the Bohm Criterion fails for the case of finite collisionality. The question is of importance considering that nearly all practical plasma processing applications involve plasmas of finite collisionality. There is, however, very little experimental work to help choose between competing models of how Bohm's Criterion fails. The question of critical importance is this: in plasmas of finite collisionality, do ions reach the Bohm speed at the location where the quasineutral plasma ends and where space charge appears? We have begun to examine the question experimentally in single ion species plasmas, and our goal is to vary the ion-neutral mean free path λ within the interval 1 < λ /λD <103 , where λD is the Debye length, and to present both plasma potential data and ion velocity distribution function profiles, measured by emissive probes and by LIF, respectively, to help us understand and assess the validity of theoretical claims. Work supported by NSF Grant No. PHY-1206421, CBET-0903783, and CBET-0903832, and U.S. Department of Energy (DOE) Grant Nos. DE-FG02- 97ER54437 and DE FG02- 03ER54728.
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…
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…
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…
Child Care Services Guide. Performance Objectives. Criterion Measures. Home Economics.
ERIC Educational Resources Information Center
Duval County School Board, Jacksonville, FL.
Several intermediate performance objectives and corresponding criterion measures are listed for each of 14 terminal objectives for a high school child care services course. This course is designed to provide opportunities for exploring a broad range of child care, guidance, and service occupations. Major concepts include characteristics of…
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,…
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…
Alignment of Lyapunov Vectors: A Quantitative Criterion to Predict Catastrophes?
Beims, Marcus W.; Gallas, Jason A. C.
2016-01-01
We argue that the alignment of Lyapunov vectors provides a quantitative criterion to predict catastrophes, i.e. the imminence of large-amplitude events in chaotic time-series of observables generated by sets of ordinary differential equations. Explicit predictions are reported for a Rössler oscillator and for a semiconductor laser with optoelectronic feedback. PMID:27845435
The Criterion Validity of Tasks of Basic Cognitive Processes
ERIC Educational Resources Information Center
Luo, Dasen; Thompson, Lee A.; Detterman, Douglas K.
2006-01-01
The present study evaluated the criterion validity of the aggregated tasks of basic cognitive processes (TBCP). In age groups from 6 to 19 of the Woodcock-Johnson III Cognitive Abilities and Achievement Tests normative sample, the aggregated TBCP, i.e., the processing speed and working memory clusters, correlate with measures of scholastic…
Alignment of Lyapunov Vectors: A Quantitative Criterion to Predict Catastrophes?
NASA Astrophysics Data System (ADS)
Beims, Marcus W.; Gallas, Jason A. C.
2016-11-01
We argue that the alignment of Lyapunov vectors provides a quantitative criterion to predict catastrophes, i.e. the imminence of large-amplitude events in chaotic time-series of observables generated by sets of ordinary differential equations. Explicit predictions are reported for a Rössler oscillator and for a semiconductor laser with optoelectronic feedback.
Food Production and Services. Performance Objectives. Criterion Measures. Home Economics.
ERIC Educational Resources Information Center
Bryant, EuDell H.; And Others
Several intermediate performance objectives and corresponding criterion measures are listed for each of eight terminal objectives for a food production and services course, which is designed to provide students with an opportunity to express and practice a broad range of food production and service occupations. Major concepts covered include…
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.
Issues and Procedures in the Development of Criterion Referenced Tests.
ERIC Educational Resources Information Center
Klein, Stephen P.; Kosecoff, Jacqueline
The basic steps and procedures in the development of criterion referenced tests (CRT), as well as the issues and problems associated with these activities are discussed. In the first section of the paper, the discussions focus upon the purpose and defining characteristics of CRTs, item construction and selection, improving item quality, content…
DPI Criterion-Referenced Pre-Reading Screening Test: Manual.
ERIC Educational Resources Information Center
Reynolds, Irene; Williams, Virginia
The DPI Criterion-Referenced Pre-Reading Screening Test is to be used as one means of identifying some strengths and weaknesses in certain areas of pre-reading skills. It is intended to be used as a screening instrument for beginning first graders. The areas of pre-reading skills to be screened are (1) auditory perception, (2) letter knowledge,…
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…
Starns, Jeffrey J; Olchowski, James E
2015-01-01
In recognition memory, participants often fail to shift their response criterion within a test even when they see cues signaling whether they should expect weak or strong memory (e.g., Stretch & Wixted Journal of Experimental Psychology: Learning, Memory, and Cognition, 24, 1397-1410, 1998b). We contrasted two possible accounts for this failure to shift. The first assumes that shifting the criterion requires effortful processing, so participants are unwilling to make shifts even when they expect different levels of strength. The second assumes that participants are unwilling to decide which strength category is indicated by the cue for each trial, so their expectations for memory strength do not change across trials. Targets appeared in different test formats ("cues") depending on whether they were studied once (weak) or five times (strong), and lures were evenly divided between the two formats. Some participants had two response keys for "old" and "new" (2-key), and others had to use different keys to respond "old" for the two strength cues (3-key). The goal of the 3-key condition was to force participants to decide which strength cue was presented on each trial. The 3-key participants had a lower false alarm rate for lures shown with the strong than with the weak cue, but the 2-key participants showed no evidence of a criterion shift. Response times were unaffected by trial-by-trial criterion shifts. We conclude that participants willingly shift their response criterion on the basis of changes in expected strength, but they are unwilling to decide which strength to expect unless they are compelled to do this by other aspects of the task.
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 unified criterion for the growth and coalescence of microvoids
NASA Astrophysics Data System (ADS)
Morin, Léo; Leblond, Jean-Baptiste; Benzerga, A. Amine; Kondo, Djimédo
2016-12-01
A yield criterion is developed which unifies void growth and void coalescence theories. Standard void growth theory assumes that plastic flow is diffuse, if not prevalent everywhere within the matrix of the elementary cell considered. On the other hand, void coalescence theory assumes states of post-localized plasticity whereby plastic flow is restricted to intervoid ligaments. The new theory accommodates both scenarios through some appropriate choice of microscopic velocity fields. An important implication for actual evolution problems is a seamless transition from void growth to void coalescence. This is in contrast with previous hybrid approaches whereby abrupt transitions are associated with the presence of unavoidable corners in the effective yield surface. More generally, the new criterion is applicable to describe yielding in porous metal plasticity for both low and high void volume fractions.
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.
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
Establishment of an equivalence acceptance criterion for accelerated stability studies.
Burdick, Richard K; Sidor, Leslie
2013-01-01
In this article, the use of statistical equivalence testing for providing evidence of process comparability in an accelerated stability study is advocated over the use of a test of differences. The objective of such a study is to demonstrate comparability by showing that the stability profiles under nonrecommended storage conditions of two processes are equivalent. Because it is difficult at accelerated conditions to find a direct link to product specifications, and hence product safety and efficacy, an equivalence acceptance criterion is proposed that is based on the statistical concept of effect size. As with all statistical tests of equivalence, it is important to collect input from appropriate subject-matter experts when defining the acceptance criterion.
Analysis of constant false alarm rate sidelobe canceller criterion
NASA Astrophysics Data System (ADS)
Reed, I. S.; Brennan, L. E.
1985-05-01
In this final report, the constant false alarm rate (CFAR) detection criterion for a sidelobe canceller (SLC) system, introduced in the last quarterly progress report, is found completely and analyzed. This new detection test for radar exhibits the desirable CFAR property that its probability of a false alarm (PFA) is functionally independent of the covariance of the actual noise field encountered. As a consequence, such a CFAR SLC system is ideally suited to cope with the newly evolving smart jammer threat to radar. An important objective, set in the last quarterly progress report, was to find both the false alarm and signal detection probabilities of this test. The first and most important of these two goals has been met. The probability of a false alarm (or PFA) of this CFAR SLC detection criterion is derived in closed form in this report. The success in finding the PFA is due primarily to the use of a generalization of Cochran's theorem.
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.
Convergent, discriminant, and criterion validity of DSM-5 traits.
Yalch, Matthew M; Hopwood, Christopher J
2016-10-01
Section III of the Diagnostic and Statistical Manual of Mental Disorders (5th edi.; DSM-5; American Psychiatric Association, 2013) contains a system for diagnosing personality disorder based in part on assessing 25 maladaptive traits. Initial research suggests that this aspect of the system improves the validity and clinical utility of the Section II Model. The Computer Adaptive Test of Personality Disorder (CAT-PD; Simms et al., 2011) contains many similar traits as the DSM-5, as well as several additional traits seemingly not covered in the DSM-5. In this study we evaluate the convergent and discriminant validity between the DSM-5 traits, as assessed by the Personality Inventory for DSM-5 (PID-5; Krueger et al., 2012), and CAT-PD in an undergraduate sample, and test whether traits included in the CAT-PD but not the DSM-5 provide incremental validity in association with clinically relevant criterion variables. Results supported the convergent and discriminant validity of the PID-5 and CAT-PD scales in their assessment of 23 out of 25 DSM-5 traits. DSM-5 traits were consistently associated with 11 criterion variables, despite our having intentionally selected clinically relevant criterion constructs not directly assessed by DSM-5 traits. However, the additional CAT-PD traits provided incremental information above and beyond the DSM-5 traits for all criterion variables examined. These findings support the validity of pathological trait models in general and the DSM-5 and CAT-PD models in particular, while also suggesting that the CAT-PD may include additional traits for consideration in future iterations of the DSM-5 system. (PsycINFO Database Record
Soft Clustering Criterion Functions for Partitional Document Clustering
2004-05-26
of the corresponding clusters. We represent the documents using the vector- space model [35]. In this model, each document d is considered to be a...vector in the space of the distinct terms present in the collection. We employ the tf-idf term-weighting scheme that represents each document d as the...produce balanced clusters. In this paper, due to space constraints, we focus on only four out of these seven criterion functions, which are referred to as
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.
Numerical fracture simulation of bend specimens using a CTOD criterion
NASA Technical Reports Server (NTRS)
Shivakumar, K. N.; Newman, J. C., Jr.
1989-01-01
Stable crack growth in 50-mm-thick side-grooved three-point bend specimens of HY-130 steel is modeled numerically. A two-dimensional elastoplastic FEM formulation incorporating a CTOD fracture criterion is developed analytically, and the theoretical predictions are compared with experimental data in graphs. Good general agreement is obtained, except for the crack extension, which was typically overpredicted. The value of the J integral at crack initiation is found to be 83 kJ/sq m.
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
Job-Relatedness of a Posttraining Job Knowledge Criterion Used to Assess Validity and Test Fairness.
ERIC Educational Resources Information Center
Distefano, M. K., Jr.; And Others
1980-01-01
Significant job-relatedness was found for a posttraining job knowledge test criterion. Content validity methods may be able to help solve the problem of criterion relevance in validation research by providing quantitative evidence of job-relatedness. (Author)
The entropy rate admissibility criterion for solution of hyperbolic conservation laws
NASA Technical Reports Server (NTRS)
Dafermos, C. M.
1972-01-01
The entropy rate admissibility criterion for solutions of hyperbolic conservation laws is numerically analyzed. The following admissibility criterion for solutions of hyperbolic conservation laws is proposed: a weak solution is admissible if the total entropy decays with the highest possible rate. The equivalence of this criterion and viscosity criterion is established for the single equation and the system of equations of one dimensional nonlinear elasticity.
ABET Criterion 3.f: how much curriculum content is enough?
Barry, B E; Ohland, M W
2012-06-01
Even after multiple cycles of ABET accreditation, many engineering programs are unsure of how much curriculum content is needed to meet the requirements of ABET's Criterion 3.f (an understanding of professional and ethical responsibility). This study represents the first scholarly attempt to assess the impact of curriculum reform following the introduction of ABET Criterion 3.f. This study sought to determine how much professional and ethical responsibility curriculum content was used between 1995 and 2005, as well as how, when, why, and to what effect changes in the amount of content occurred. Subsequently, the study sought to evaluate if different amounts of curriculum content generated differing student outcomes. The amount of curriculum content used by each of the participating programs was identified during semi-structured interviews with program administrators and a review of ABET Self-Study documents. Quantitative methods were applied to determine if a relationship existed between the curriculum content and performance on a nationally administered, engineering-specific standardized examination. The findings indicate a statistical relationship, but a lack of structure between the amount of required content in the curriculum and performance on the examination. Additional findings were also generated regarding the way that programs interpret the Criterion 3.f feedback generated during accreditation visits. The primary impact of this study is that it dispels the myth that more courses or course time on professionalism and ethics will necessarily lead to positive engineering education outcomes. Much of the impetus to add more curriculum content results from a lack of conclusive feedback during ABET accreditation visits.
Failure criterion for materials with spatially correlated mechanical properties.
Faillettaz, J; Or, D
2015-03-01
The role of spatially correlated mechanical elements in the failure behavior of heterogeneous materials represented by fiber bundle models (FBMs) was evaluated systematically for different load redistribution rules. Increasing the range of spatial correlation for FBMs with local load sharing is marked by a transition from ductilelike failure characteristics into brittlelike failure. The study identified a global failure criterion based on macroscopic properties (external load and cumulative damage) that is independent of spatial correlation or load redistribution rules. This general metric could be applied to assess the mechanical stability of complex and heterogeneous systems and thus provide an important component for early warning of a class of geophysical ruptures.
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.
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.
Width Criterion For Weld-Seam-Tracking Data
NASA Technical Reports Server (NTRS)
Lincir, Mark R.
1993-01-01
Image-processing algorithm in "through-torch-vision" (T3V) system developed to guide gas/tungsten arc welding robot along weld seam modified, according to proposal, reducing incidence of inaccurate tracking of weld seam. Developmental system intended to provide closed-loop control of motion of welding robot along weld seam on basis of lines in T3V image identified by use of image-processing algorithm and assumed to coincide with edges of weld seam. Use of width criterion prevents tracking of many false pairs of lines, with consequent decrease in incidence of inaccurate tracking and increase in confidence in weld-tracking capability of robotic welding system.
A new yield criterion for the concrete materials
NASA Astrophysics Data System (ADS)
François, Marc
2008-05-01
The yield criterion proposed depends upon two material constants and is proven to be smooth and convex under a simple condition. These properties induce a mathematical robustness that allows a further use in a damage mechanics model. The analytical gradient and Hessian are given. The obtained yield surface is relevant to Kupfer's biaxial testings on concrete. The identification procedure, with respect to the classical uniaxial tension and compression testings, is detailed. To cite this article: M. François, C. R. Mecanique 336 (2008).
Discrete Lange-Newell criterion for dissipative systems.
Ndzana, Fabien I I; Mohamadou, Alidou; Kofané, Timoleon Crépin
2009-05-01
We report on the derivation of the discrete complex Ginzburg-Landau equation with first- and second-neighbor couplings using a nonlinear electrical network. Furthermore, we discuss theoretically and numerically modulational instability of plane carrier waves launched through the line. It is pointed out that the underlying analysis not only spells out the discrete Lange-Newell criterion by the means of the linear stability analysis at which the modulational instability occurs for the generation of a train of ultrashort pulses, but also characterizes the long-time dynamical behavior of the system when the instability grows.
Optimization of the Structures at Shakedown and Rosen's Optimality Criterion
NASA Astrophysics Data System (ADS)
Alawdin, Piotr; Atkociunas, Juozas; Liepa, Liudas
2016-09-01
Paper focuses on the problems of application of extreme energy principles and nonlinear mathematical programing in the theory of structural shakedown. By means of energy principles, which describes the true stress-strain state conditions of the structure, the dual mathematical models of analysis problems are formed (static and kinematic formulations). It is shown how common mathematical model of the structures optimization at shakedown with safety and serviceability constraints (according to the ultimate limit state (ULS) and serviceability limit state (SLS) requirements) on the basis of previously mentioned mathematical models is formed. The possibilities of optimization problem solution in the context of physical interpretation of optimality criterion of Rosen's algorithm are analyzed.
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.
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.
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
An empirical hypothesis of deformation rate ratio criterion
NASA Astrophysics Data System (ADS)
Li, S.
1996-04-01
Based on the experiences obtained from more than 10 years' monitoring of tunnel excavation in soft ground, and in order to solve the problem that the currently-used surrounding rock stability criteria have nothing to do with the rockbolts-shotcrete support operation, thus they are hard to be applied by in-situ engineers, the author puts forward a new empirical hypothesis of criterion for surrounding rock stability assessment. Then five case histories are described as references. Furthermore, the open complex giant system methodology is introduced to explain the theory and practice of empirical hypothesis.
Elaboration and Application of a Theory of Criterion-Referenced Reliability.
ERIC Educational Resources Information Center
Lovett, Hubert T.
The reliability of a criterion referenced test was defined as a measure of the degree to which the test discriminates between an individual's level of performance and a predetermined criterion level. The variances of observed and true scores were defined as the squared deviation of the score from the criterion. Based on these definitions and the…
16 CFR 1631.34 - Small carpets and rugs not meeting acceptance criterion.
Code of Federal Regulations, 2010 CFR
2010-01-01
... acceptance criterion. 1631.34 Section 1631.34 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION...) Rules and Regulations § 1631.34 Small carpets and rugs not meeting acceptance criterion. (a) If any... acceptance criterion of such standard, it shall, prior to its introduction into commerce, be legibly...
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.
A one-class kernel fisher criterion for outlier detection.
Dufrenois, Franck
2015-05-01
Recently, Dufrenois and Noyer proposed a one class Fisher's linear discriminant to isolate normal data from outliers. In this paper, a kernelized version of their criterion is presented. Originally on the basis of an iterative optimization process, alternating between subspace selection and clustering, I show here that their criterion has an upper bound making these two problems independent. In particular, the estimation of the label vector is formulated as an unconstrained binary linear problem (UBLP) which can be solved using an iterative perturbation method. Once the label vector is estimated, an optimal projection subspace is obtained by solving a generalized eigenvalue problem. Like many other kernel methods, the performance of the proposed approach depends on the choice of the kernel. Constructed with a Gaussian kernel, I show that the proposed contrast measure is an efficient indicator for selecting an optimal kernel width. This property simplifies the model selection problem which is typically solved by costly (generalized) cross-validation procedures. Initialization, convergence analysis, and computational complexity are also discussed. Lastly, the proposed algorithm is compared with recent novelty detectors on synthetic and real data sets.
Setting criterion thresholds for estimating prevalence: what is being validated?
Gambino, Blase
2014-09-01
Much of the debate over how best to estimate the prevalence of problem gambling in the general population is driven by a number of misconceptions, misinterpretations, and questionable, sometimes erroneous assumptions. Among the latter is the failure to understand that what is being validated is not the test but the interpretation of test scores for a specific purpose. In addition there has been a lack of attention to defining the clinical and/or epidemiologic relevance of case definitions in terms of severity and other clinical attributes, a misunderstanding of how test values are interpreted when criterion thresholds or cut-off points are selected, and a failure to replicate the validation of criterion thresholds for defining cases of problem gambling. It is argued further that the distinction between dichotomy and continuum is a false choice, and any emphasis on overestimation is misdirected. Alternative methods for evaluating tests and estimating prevalence are described and a pragmatic empirical approach to the interpretation of prevalence estimates is recommended.
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.
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
Refocusing criterion via sparsity measurements in digital holography.
Memmolo, Pasquale; Paturzo, Melania; Javidi, Bahram; Netti, Paolo A; Ferraro, Pietro
2014-08-15
Several automatic approaches have been proposed in the past to compute the refocus distance in digital holography (DH). However most of them are based on a maximization or minimization of a suitable amplitude image contrast measure, regarded as a function of the reconstruction distance parameter. Here we show that, by using the sparsity measure coefficient regarded as a refocusing criterion in the holographic reconstruction, it is possible to recover the focus plane and, at the same time, establish the degree of sparsity of digital holograms, when samples of the diffraction Fresnel propagation integral are used as a sparse signal representation. We employ a sparsity measurement coefficient known as Gini's index thus showing for the first time, to the best of our knowledge, its application in DH, as an effective refocusing criterion. Demonstration is provided for different holographic configurations (i.e., lens and lensless apparatus) and for completely different objects (i.e., a thin pure phase microscopic object as an in vitro cell, and macroscopic puppets) preparation.
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.
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
Gene Selection for Multiclass Prediction by Weighted Fisher Criterion
2007-01-01
Gene expression profiling has been widely used to study molecular signatures of many diseases and to develop molecular diagnostics for disease prediction. Gene selection, as an important step for improved diagnostics, screens tens of thousands of genes and identifies a small subset that discriminates between disease types. A two-step gene selection method is proposed to identify informative gene subsets for accurate classification of multiclass phenotypes. In the first step, individually discriminatory genes (IDGs) are identified by using one-dimensional weighted Fisher criterion (wFC). In the second step, jointly discriminatory genes (JDGs) are selected by sequential search methods, based on their joint class separability measured by multidimensional weighted Fisher criterion (wFC). The performance of the selected gene subsets for multiclass prediction is evaluated by artificial neural networks (ANNs) and/or support vector machines (SVMs). By applying the proposed IDG/JDG approach to two microarray studies, that is, small round blue cell tumors (SRBCTs) and muscular dystrophies (MDs), we successfully identified a much smaller yet efficient set of JDGs for diagnosing SRBCTs and MDs with high prediction accuracies (96.9% for SRBCTs and 92.3% for MDs, resp.). These experimental results demonstrated that the two-step gene selection method is able to identify a subset of highly discriminative genes for improved multiclass prediction. PMID:17713593
A Multi Fluid Analysis of the Ignition Criterion
NASA Astrophysics Data System (ADS)
Guazzotto, Luca; Betti, Riccardo
2016-10-01
In magnetic confinement nuclear fusion experiments, performance with respect to ignition is expressed in terms of the Lawson criterion, a zero-dimensional, single-fluid, steady-state power balance expressing the plasma properties needed for ignition through the energy confinement time τE and the plasma temperature and density. Several improvements to the classical criterion are investigated. Ions, electrons and α particles are allowed to have different energy confinement times and energy coupling times are expressed through physics-based relations. The effect of multi-fluid physics is examined in a steady-state analysis and for the time-dependent case, which requires a nonlinear treatment more detailed than the standard `` Ṫ vs . T'' single-fluid one. A one-dimensional analysis is also considered to investigate the importance of density and temperature profiles on the τE needed for ignition. Rather than by solving the 1D transport equations, this is done with a parametric study. This work was performed under DOE Grant DE-FG02-93ER54215.
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.
A criterion to maximize the irreversible efficiency in heat engines
NASA Astrophysics Data System (ADS)
Aragón-González, G.; Canales-Palma, A.; León-Galicia, A.; Musharrafie-Martínez, M.
2003-02-01
The purpose of this work is to obtain a more precise calculation of the effective limits to the efficiency, of several cyclic heat engines. This calculation is based, first, on the equations describing the irreversible efficiency, and second, on a method which results from a general criterion to maximize this efficiency, applicable to several heat engines. With this method, we apply the criterion to maximize efficiencies; establish lower and upper bounds, corresponding to the efficiencies of Curzon-Ahlborn-like and Carnot-like heat engines; and, finally, find analytical or numerical expressions for the efficiencies etame and etamax. etamax is the maximum irreversible efficiency; etame is the efficiency in which the irreversible efficiency achieves its maximum, in a similar way to the Curzon-Ahlborn efficiency (maximum work or power). The method was applied to a Brayton cycle, presenting internal dissipations of the working fluid and irreversibilities due to the finite-rate heat transfer between the heat engine and its reservoirs. Also, we applied this method to a Carnot cycle including the irreversibilities of a finite-rate heat transfer between the heat engine and its reservoirs, heat leak between the reservoirs, and internal dissipations of the working fluid. The results obtained for the Brayton cycle are more general and useful than those in the relevant literature.
PET image reconstruction: mean, variance, and optimal minimax criterion
NASA Astrophysics Data System (ADS)
Liu, Huafeng; Gao, Fei; Guo, Min; Xue, Liying; Nie, Jing; Shi, Pengcheng
2015-04-01
Given the noise nature of positron emission tomography (PET) measurements, it is critical to know the image quality and reliability as well as expected radioactivity map (mean image) for both qualitative interpretation and quantitative analysis. While existing efforts have often been devoted to providing only the reconstructed mean image, we present a unified framework for joint estimation of the mean and corresponding variance of the radioactivity map based on an efficient optimal min-max criterion. The proposed framework formulates the PET image reconstruction problem to be a transformation from system uncertainties to estimation errors, where the minimax criterion is adopted to minimize the estimation errors with possibly maximized system uncertainties. The estimation errors, in the form of a covariance matrix, express the measurement uncertainties in a complete way. The framework is then optimized by ∞-norm optimization and solved with the corresponding H∞ filter. Unlike conventional statistical reconstruction algorithms, that rely on the statistical modeling methods of the measurement data or noise, the proposed joint estimation stands from the point of view of signal energies and can handle from imperfect statistical assumptions to even no a priori statistical assumptions. The performance and accuracy of reconstructed mean and variance images are validated using Monte Carlo simulations. Experiments on phantom scans with a small animal PET scanner and real patient scans are also conducted for assessment of clinical potential.
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.
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 generalized smoothness criterion for acoustic-to-articulatory inversion
Ghosh, Prasanta Kumar; Narayanan, Shrikanth
2010-01-01
The many-to-one mapping from representations in the speech articulatory space to acoustic space renders the associated acoustic-to-articulatory inverse mapping non-unique. Among various techniques, imposing smoothness constraints on the articulator trajectories is one of the common approaches to handle the non-uniqueness in the acoustic-to-articulatory inversion problem. This is because, articulators typically move smoothly during speech production. A standard smoothness constraint is to minimize the energy of the difference of the articulatory position sequence so that the articulator trajectory is smooth and low-pass in nature. Such a fixed definition of smoothness is not always realistic or adequate for all articulators because different articulators have different degrees of smoothness. In this paper, an optimization formulation is proposed for the inversion problem, which includes a generalized smoothness criterion. Under such generalized smoothness settings, the smoothness parameter can be chosen depending on the specific articulator in a data-driven fashion. In addition, this formulation allows estimation of articulatory positions recursively over time without any loss in performance. Experiments with the MOCHA TIMIT database show that the estimated articulator trajectories obtained using such a generalized smoothness criterion have lower RMS error and higher correlation with the actual measured trajectories compared to those obtained using a fixed smoothness constraint. PMID:20968386
A Reconsideration of the Extension Strain Criterion for Fracture and Failure of Rock
NASA Astrophysics Data System (ADS)
Wesseloo, J.; Stacey, T. R.
2016-12-01
The complex behaviours of rocks and rock masses have presented paradoxes to the rock engineer, including the fracturing of seemingly strong rock under low stress conditions, which often occurs near excavation boundaries. The extension strain criterion was presented as a fracture initiation criterion under these conditions (Stacey in Int J Rock Mech Min Sci 18:469-474, 1981). This criterion has been used successfully by some and criticised by others. In this paper, we review the literature on the extension strain criterion and present a case for the correct interpretation of the criterion and the conditions suitable for its use. We argue that the extension strain criterion can also be used to provide an indication of damage level under conditions of relatively low confining stress. We also present an augmentation of the criterion, the ultimate extension strain, which is applicable under extensional loading conditions when σ 2 is similar in magnitude to σ 1.
ERIC Educational Resources Information Center
Vrieze, Scott I.
2012-01-01
This article reviews the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) in model selection and the appraisal of psychological theory. The focus is on latent variable models, given their growing use in theory testing and construction. Theoretical statistical results in regression are discussed, and more important…
Criterion Related Validity of Karate Specific Aerobic Test (KSAT)
Chaabene, Helmi; Hachana, Younes; Franchini, Emerson; Tabben, Montassar; Mkaouer, Bessem; Negra, Yassine; Hammami, Mehrez; Chamari, Karim
2015-01-01
Background: Karate is one the most popular combat sports in the world. Physical fitness assessment on a regular manner is important for monitoring the effectiveness of the training program and the readiness of karatekas to compete. Objectives: The aim of this research was to examine the criterion related to validity of the karate specific aerobic test (KSAT) as an indicator of aerobic level of karate practitioners. Patients and Methods: Cardiorespiratory responses, aerobic performance level through both treadmill laboratory test and YoYo intermittent recovery test level 1 (YoYoIRTL1) as well as time to exhaustion in the KSAT test (TE’KSAT) were determined in a total of fifteen healthy international karatekas (i.e. karate practitioners) (means ± SD: age: 22.2 ± 4.3 years; height: 176.4 ± 7.5 cm; body mass: 70.3 ± 9.7 kg and body fat: 13.2 ± 6%). Results: Peak heart rate obtained from KSAT represented ~99% of maximal heart rate registered during the treadmill test showing that KSAT imposes high physiological demands. There was no significant correlation between KSAT’s TE and relative (mL/min kg) treadmill maximal oxygen uptake (r = 0.14; P = 0.69; [small]). On the other hand, there was a significant relationship between KSAT’s TE and the velocity associated with VO2max (vVO2max) (r = 0.67; P = 0.03; [large]) as well as the velocity at VO2 corresponding to the second ventilatory threshold (vVO2 VAT) (r = 0.64; P = 0.04; [large]). Moreover, significant relationship was found between TE’s KSAT and both the total distance covered and parameters of intermittent endurance measured through YoYoIRTL1. Conclusions: The KSAT has not proved to have indirect criterion related validity as no significant correlations have been found between TE’s KSAT and treadmill VO2max. Nevertheless, as correlated to other aerobic fitness variables, KSAT can be considered as an indicator of karate specific endurance. The establishment of the criterion related validity of the KSAT
Threshold criterion for a space simulation beam-plasma discharge
NASA Technical Reports Server (NTRS)
Szuszczewicz, E. P.; Walker, D. N.; Papadopoulos, K.; Bernstein, W.; Lin, C. S.
1982-01-01
An experimental and theoretical study of the threshold characteristics of a space simulation beam-plasma discharge with emphasis on density profiles and a density-dependent ignition criterion. The study included various beam-plasma conditions covering beam currents from 8 to 85 mA, beam energies from 0.8 to 2.0 keV, and magnetic fields at 0.9 and 1.5 G. The study included experimental determinations of radial profiles of electron density for each of the selected conditions extending from a low-density, pre-beam-plasma discharge state to a strong beam-plasma discharge condition. The experimental results are shown to agree with detailed model calculations, which consider the beam-plasma discharge to be produced by large-amplitude electron plasma waves resulting from the beam-plasma interaction.
A physically based failure criterion for laminated composites
NASA Astrophysics Data System (ADS)
Kroll, L.; Hufenbach, W.
1999-07-01
The stress and strain fields in laminated composites can be described realistically with the help of a refined theory of elasticity for anisotropic materials. In contrast, the respective failure characteristics cannot be predicted satisfactorily based on the commonly used failure criteria. The main disadvantage of these generalized failure criteria, such as the quadratic failure criteria of Sakharov, Azzi/Tsai, Tsai/Wu, etc., is that they combine fundamentally different fracture mechanisms of the homogenized UD layer in one approximation by an interpolation polynomial. A completely different method for the formulation of realistic failure criteria, taking into account the heterogeneous anisotropic material structure relevant to the fracture, is based on the Mohr hypothesis for brittle materials that in fact only the stresses in the fracture plane induce failure. This physically based failure criterion not only considers the decisive eifference between the fiber fracture and the interfiber fracture, but also characterizes further fracture types in the plane parallel to the fibers.
Landau criterion for an anisotropic Bose-Einstein condensate
NASA Astrophysics Data System (ADS)
Yu, Zeng-Qiang
2017-03-01
In this work we discuss the Landau criterion for anisotropic superfluidity. To this end we consider a pointlike impurity moving in a uniform Bose-Einstein condensate with either interparticle dipole-dipole interaction or Raman-induced spin-orbit coupling. In both cases we find that the Landau critical velocity vc is generally smaller than the sound velocity in the moving direction. Beyond vc, the energy dissipation rate is explicitly calculated via a perturbation approach. In the plane-wave phase of a spin-orbit-coupled Bose gas, the dissipationless motion is suppressed by the Raman coupling even in the direction orthogonal to the recoil momentum. Our predictions can be tested in the experiments with ultracold atoms.
Error sensitivity to refinement: a criterion for optimal grid adaptation
NASA Astrophysics Data System (ADS)
Luchini, Paolo; Giannnetti, Flavio; Citro, Vincenzo
2016-11-01
Most indicators used for automatic grid refinement are suboptimal, in the sense that they do not really minimize the global solution error. This paper concerns with a new indicator, related to the sensitivity map of global stability problems, suitable for an optimal grid refinement that minimizes the global solution error. The new criterion is derived from the properties of the adjoint operator and provides a map of the sensitivity of the global error (or its estimate) to a local mesh refinement. Examples are presented for both a scalar partial differential equation and for the system of Navier-Stokes equations. In the last case, we also present a grid-adaptation algorithm based on the new estimator and on the FreeFem++ software that improves the accuracy of the solution of almost two order of magnitude by redistributing the nodes of the initial computational mesh.
Continuous control of chaos based on the stability criterion.
Yu, Hong Jie; Liu, Yan Zhu; Peng, Jian Hua
2004-06-01
A method of chaos control based on stability criterion is proposed in the present paper. This method can stabilize chaotic systems onto a desired periodic orbit by a small time-continuous perturbation nonlinear feedback. This method does not require linearization of the system around the stabilized orbit and only an approximate location of the desired periodic orbit is required which can be automatically detected in the control process. The control can be started at any moment by choosing appropriate perturbation restriction condition. It seems that more flexibility and convenience are the main advantages of this method. The discussions on control of attitude motion of a spacecraft, Rössler system, and two coupled Duffing oscillators are given as numerical examples.
Biomechanical analysis of injury criterion for child and adult dummies.
Sances, A
2000-01-01
The development of human injury tolerance is difficult because of the physical differences between humans and animals, the available dummies, and tissue of the cadaver. Furthermore, human volunteer testing can clearly only be done at subinjurious levels. While considerable biomechanical injury evidence exists for the adult human based on cadaveric studies, little information is available for the pediatric population. However, some material is available from skull bone modulus studies and from the fetal tendon strength and early pediatric studies of the newborn. A review of living human, animal, and human cadaveric studies, which forms the basis for head-neck injury criterion are given. Examples of the use of the Hybrid III dummy for injury prediction such as in the Malibu rollover tests and air bag mechanisms show neck injury levels are considerably above the proposed Malibu 2000 N level.
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.
Failure criterion of glass fabric reinforced plastic laminates
NASA Technical Reports Server (NTRS)
Haga, O.; Hayashi, N.; Kasuya, K.
1986-01-01
Failure criteria are derived for several modes of failure (in unaxial tensile or compressive loading, or biaxial combined tensile-compressive loading) in the case of closely woven plain fabric, coarsely-woven plain fabric, or roving glass cloth reinforcements. The shear strength in the interaction formula is replaced by an equation dealing with tensile or compressive strength in the direction making a 45 degree angle with one of the anisotropic axes, for the uniaxial failure criteria. The interaction formula is useful as the failure criterion in combined tension-compression biaxial failure for the case of closely woven plain fabric laminates, but poor agreement is obtained in the case of coarsely woven fabric laminates.
Validation of criterion-referenced archery cutting scores.
Ishee, J H; Titlow, L W
1993-04-01
This study investigated an empirical method for setting optimal cutting scores for a criterion-referenced archery test. The classification-outcome probabilities and approaches to validity suggested by Berk were utilized. Pretest scores were obtained on 35 uninstructed college-age women on six ends (six arrows each) from 20 yards (18.3 m) after an unrecorded warm-up end. Posttest scores were after 15 weeks of instruction. Score distributions were the primary determinant for accurately classifying students as true mastery and true nonmastery. Accuracy is a function of the amount of overlap between distributions. Using the point at which the distributions overlapped, classification accuracy was estimated. Probabilities associated with 80 points were p(TM) + p(TN) = .83 and p(FM) + p(FN) = .14. Scores above and below 80 points had lower probabilities of classification accuracy. Reliability estimated using Kappa was .59. Statistical validity of the cutting score (phi) was .68.
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.
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
Local versus average field failure criterion in amorphous polymers
NASA Astrophysics Data System (ADS)
Xie, Yuesong; Mao, Yunzhe; Sun, Lin; Koslowski, Marisol
2015-03-01
There is extensive work developing laws that predict yielding in amorphous polymers, ranging from the pioneer experimental work of Sternstein et al (1968 Appl. Polym. Symp. 7 175-99) to the novel molecular dynamics simulations of Jaramillo et al (2012 Phys. Rev. B 85 024114). While atomistic models render damage criteria in terms of local values of the stress and strain fields, experiments provide yield conditions in terms of the average values of these fields. Unfortunately, it is not possible to compare these results due to the differences in time and length scales. Here, we use a micromechanical phase-field damage model with parameters calculated from atomistic simulations to connect atomistic and macroscopic scale experiments. The phase-field damage model is used to study failure in composite materials. We find that the yield criterion should be described in terms of local stress and strains fields and cannot be extended directly from applied stress field values to determine yield conditions.
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.
Toropova, Alla P; Toropov, Andrey A
2017-02-11
New criterion of the predictive potential of quantitative structure-property/activity relationships (QSPRs/QSARs) is suggested. This criterion is calculated with utilization of the correlation coefficient between experimental and calculated values of endpoint for the calibration set, with taking into account the positive and negative dispersions between experimental and calculated values. The utilization of this criterion improves the predictive potential of QSAR models of dermal permeability coefficient, logKp (cm/h).
A Criterion for Maximally Six-Qubit Entangled States via Coefficient Matrix
NASA Astrophysics Data System (ADS)
Yu, Yan; Zha, Xin Wei; Li, Wei
2017-03-01
In a recent paper (J. Phys. A: Math. Theor 45, 075308 (2012)), Li et al. established the coefficient matrix of six-qubit entangled states. With an emphasis on six qubits, we present a new criterion for maximally six-qubit entangled states via those coefficient matrices. By calculating the determinants of coefficient matrix, one use the criterion that characterize these states. Moreover, the criterion via the coefficient matrices gives rise to the combination of maximally multi-qubit entangled state(MMES) and matrix, and we believe that the new criterion can play an important role in quantum information.
Weathers, Frank W; Keane, Terence M
2007-04-01
The Criterion A problem in the field of traumatic stress refers to the stressor criterion for posttraumatic stress disorder (PTSD) and involves a number of fundamental issues regarding the definition and measurement of psychological trauma. These issues first emerged with the introduction of PTSD as a diagnostic category in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III; American Psychiatric Association, 1980) and continue to generate considerable controversy. In this article, the authors provide an update on the Criterion A problem, with particular emphasis on the evolution of the DSM definition of the stressor criterion and the ongoing debate regarding broad versus narrow conceptualizations of traumatic events.
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.
Measuring unconscious cognition: Beyond the zero-awareness criterion
Schmidt, Thomas
2008-01-01
Visual masking can be employed to manipulate observers’ awareness of critical stimuli in studies of masked priming. This paper discusses two different lines of attack for establishing unconscious cognition in such experiments. Firstly, simple dissociations between direct measures (D) of visual awareness and indirect measures (I) of processing per se occur when I has some nonzero value while D is at chance level; the traditional requirement of zero awareness is necessary for this criterion only. In contrast, double dissociations occur when some experimental manipulation has opposite effects on I and D, for instance, increasing priming effects despite decreasing prime identification performance (Schmidt & Vorberg, 2006). Double dissociations require much weaker measurement assumptions than other criteria. An attractive alternative to this dissociation approach would be to use tasks that are known to violate necessary conditions of visual awareness altogether. In particular, it is argued here that priming effects in speeded pointing movements (Schmidt, Niehaus, & Nagel, 2006) occur in the absence of the recurrent processing that is often assumed to be a necessary condition for awareness (for instance, DiLollo, Enns, & Rensink, 2000; Lamme & Roelfsema, 2000). Feedforward tasks such as this might thus be used to measure the time-course of unconscious processing directly, before intracortical feedback and awareness come into play. PMID:20517514
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.
Failure Criterion of Rock with Multiple Friction Angles
NASA Astrophysics Data System (ADS)
Harvieux, J.; Makhnenko, R. Y.; Labuz, J. F.
2015-12-01
The Paul-Mohr-Coulomb failure criterion is a linear function of the three principal stresses, and it can be written as AσI + BσII + CσIII = 1, where σI, σII, and σIII are the major, intermediate, and minor principal stresses and A, B, and C are material parameters related to the friction angles in compression and extension and the (theoretical) uniform triaxial tensile strength. Conventional triaxial compression (σII = σIII), extension (σI = σII), and plane strain (σI ≠ σII ≠ σIII) experiments were performed on dry Indiana limestone, and the stress states at failure were represented in principal stress space. Assuming isotropic behavior, a six-sided pyramidal failure surface was constructed by fitting a plane to the triaxial compression and extension data. The material parameters were determined, and the friction angle in extension was greater than the friction angle in compression, a sufficient condition for an intermediate stress effect. Multi-axial (plane strain) data were included and a twelve-sided failure surface with two different vertices was formed. The two vertices provide a change in the cross-section of the failure surface normal to the hydrostatic axis, which is often observed in failure of rock. The irregular dodecagon is associated with six parameters: two vertices and four friction angles.
Some remarks on relativistic diffusion and the spectral dimension criterion
NASA Astrophysics Data System (ADS)
Muniz, C. R.; Cunha, M. S.; Filho, R. N. Costa; Bezerra, V. B.
2015-01-01
The spectral dimension ds for high energies is calculated using the Relativistic Schrödinger Equation Analytically Continued (RSEAC) instead of the so-called Telegraph's equation (TE), in both ultraviolet (UV) and infrared (IR) regimens. Regarding the TE, the recent literature presents difficulties related to its stochastic derivation and interpretation, advocating the use of the RSEAC to properly describe the relativistic diffusion phenomena. Taking into account that the Lorentz symmetry is broken in UV regime at Lifshitz point, we show that there exists a degeneracy in very high energies, meaning that both the RSEAC and TE correctly describe the diffusion processes at these energy scales, at least under the spectral dimension criterion. In fact, both the equations yield the same result, namely, ds=2 , a dimensional reduction that is compatible with several theories of quantum gravity. This result is reached even when one takes into account a cosmological model, as for example, the de Sitter universe. On the other hand, in the IR regimen, such degeneracy is lifted in favor of the approach via TE, due to the fact that only this equation provides the correct value for ds, which is equal to the actual number of spacetime dimensions, i.e., ds=4 , while RSEAC yields ds=3 , so that a diffusing particle described by this method experiences a three-dimensional spacetime.
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.
Nonlinear viscoelasticity and generalized failure criterion for biopolymer gels
NASA Astrophysics Data System (ADS)
Divoux, Thibaut; Keshavarz, Bavand; Manneville, Sébastien; McKinley, Gareth
2016-11-01
Biopolymer gels display a multiscale microstructure that is responsible for their solid-like properties. Upon external deformation, these soft viscoelastic solids exhibit a generic nonlinear mechanical response characterized by pronounced stress- or strain-stiffening prior to irreversible damage and failure, most often through macroscopic fractures. Here we show on a model acid-induced protein gel that the nonlinear viscoelastic properties of the gel can be described in terms of a 'damping function' which predicts the gel mechanical response quantitatively up to the onset of macroscopic failure. Using a nonlinear integral constitutive equation built upon the experimentally-measured damping function in conjunction with power-law linear viscoelastic response, we derive the form of the stress growth in the gel following the start up of steady shear. We also couple the shear stress response with Bailey's durability criteria for brittle solids in order to predict the critical values of the stress σc and strain γc for failure of the gel, and how they scale with the applied shear rate. This provides a generalized failure criterion for biopolymer gels in a range of different deformation histories. This work was funded by the MIT-France seed fund and by the CNRS PICS-USA scheme (#36939). BK acknowledges financial support from Axalta Coating Systems.
An Analytic Criterion for Turbulent Disruption of Planetary Resonances
NASA Astrophysics Data System (ADS)
Batygin, Konstantin; Adams, Fred C.
2017-03-01
Mean motion commensurabilities in multi-planet systems are an expected outcome of protoplanetary disk-driven migration, and their relative dearth in the observational data presents an important challenge to current models of planet formation and dynamical evolution. One natural mechanism that can lead to the dissolution of commensurabilities is stochastic orbital forcing, induced by turbulent density fluctuations within the nebula. While this process is qualitatively promising, the conditions under which mean motion resonances can be broken are not well understood. In this work, we derive a simple analytic criterion that elucidates the relationship among the physical parameters of the system, and find the conditions necessary to drive planets out of resonance. Subsequently, we confirm our findings with numerical integrations carried out in the perturbative regime, as well as direct N-body simulations. Our calculations suggest that turbulent resonance disruption depends most sensitively on the planet–star mass ratio. Specifically, for a disk with properties comparable to the early solar nebula with α ={10}-2, only planet pairs with cumulative mass ratios smaller than ({m}1+{m}2)/M≲ {10}-5∼ 3{M}\\oplus /{M}ȯ are susceptible to breaking resonance at semimajor axis of order a∼ 0.1 {au}. Although turbulence can sometimes compromise resonant pairs, an additional mechanism (such as suppression of resonance capture probability through disk eccentricity) is required to adequately explain the largely non-resonant orbital architectures of extrasolar planetary systems.
Associative false recognition occurs without strategic criterion shifts.
Gallo, D A; Roediger, H L; McDermott, K B
2001-09-01
In the DRM (Deese/Roediger and McDermott) false memory paradigm, subjects studied lists of words associated with nonpresented critical words. They were tested in one of four instructional conditions. In a standard condition, subjects were not warned about the DRM Effect. In three other conditions, they were told to avoid false recognition of critical words. One group was warned before study of the lists (affecting encoding and retrieval processes), and two groups were warned after study (affecting only retrieval processes). Replicating prior work, the warning before study considerably reduced false recognition. The warning after study also reduced false recognition, but only when critical items had never been studied; when critical items were studied in half the lists so that subjects had to monitor memory for their presence or absence, the warning after study had little effect on false recognition. Because warned subjects were trying to avoid false recognition, the high levels of false recognition in the latter condition cannot be due to strategically guessing that critical test items were studied. False memories in the DRM paradigm are not caused by such liberal criterion shifts.
Sheath formation criterion in magnetized electronegative plasmas with thermal ions
Hatami, M. M.; Shokri, B.
2013-03-15
Taking into account the effect of collisions and positive ion temperatures, the sheath formation criterion is investigated in a weakly magnetized electronegative plasma consisting of electrons, negative and positive ions by using the hydrodynamics equations. It is assumed that the electron and negative ion density distributions are the Boltzmann distribution with two different temperatures. Also, it is assumed that the velocity of positive ions at the sheath edge is not normal to the wall (oblique entrance). Our results show that a sheath region will be formed when the initial velocity of positive ions or the ion Mach number M lies in a specific interval with particular upper and lower limits. Also, it is shown that the presence of the magnetic field affects both of these limits. Moreover, as an practical application, the density distribution of charged particles in the sheath region is studied for an allowable value of M, and it is seen that monotonically reduction of the positive ion density distribution leading to the sheath formation occurs only when M lies between two above mentioned limits.
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.
Design of cellular porous biomaterials for wall shear stress criterion.
Chen, Yuhang; Zhou, Shiwei; Cadman, Joseph; Li, Qing
2010-11-01
The microfluidic environment provided by implanted prostheses has a decisive influence on the viability, proliferation and differentiation of cells. In bone tissue engineering, for instance, experiments have confirmed that a certain level of wall shear stress (WSS) is more advantageous to osteoblastic differentiation. This paper proposes a level-set-based topology optimization method to regulate fluidic WSS distribution for design of cellular biomaterials. The topological boundary of fluid phase is represented by a level-set model embedded in a higher-dimensional scalar function. WSS is determined by the computational fluid dynamics analysis in the scale of cellular base cells. To achieve a uniform WSS distribution at the solid-fluid interface, the difference between local and target WSS is taken as the design criterion, which determines the speed of the boundary evolution in the level-set model. The examples demonstrate the effectiveness of the presented method and exhibit a considerable potential in the design optimization and fabrication of new prosthetic cellular materials for bioengineering applications.
Sound speed criterion for two-phase critical flow
NASA Astrophysics Data System (ADS)
Chung, M.-S.; Park, S.-B.; Lee, H.-K.
2004-09-01
Critical flow simulation for non-homogeneous, non-equilibrium two-phase flows is improved by applying a new sound speed model which is derived from the characteristic analysis of hyperbolic two-fluid model. The hyperbolicity of two-fluid model was based on the concept of surface tension for the interfacial pressure jump terms in the momentum equations. Real eigenvalues obtained as the closed-form solution of characteristic polynomial represent the sound speeds in the bubbly flow regime that agree well with the existing experimental data. The analytic sound speed is consistent with that obtained by the earlier study of Nguyen et al. though there is a difference between them especially in the limiting condition. The present sound speed shows more reasonable result in that condition than Nguyen et al.'s does. The present critical flow criterion derived by the present sound speed is employed in the MARS code and is assessed by treating several nozzle flow tests. The assessment results, without any adjustment made by some discharge coefficients, demonstrate more accurate predictions of critical flow rate than those of the earlier critical flow calculations in the bubbly flow regime.
Nonlinear theoretical formulation of elastic stability criterion of crystal solids
NASA Astrophysics Data System (ADS)
Wang, Hao; Li, Mo
2012-03-01
An elastic stability criterion is generally formulated based on local elasticity, where the second-order elastic constants of a crystalline system in an arbitrary deformed state are required. While simple in formalism, such a formulation demands extensive computational effort in either an ab initio calculation or an atomistic simulation and often lacks clear physical interpretation. Here, we present a nonlinear theoretical formulation employing higher-order elastic constants beyond the second-order ones; the elastic constants needed in the theory are those at a zero stress state or in any arbitrary deformed state, many of which are now available. We use the published second- and higher-order elastic constants of several cubic crystals, including Au, Al, and Cu, as well as diamond-structure Si, with transcription under different coordinate frames, to test the stability conditions of these crystals under uniaxial and hydrostatic loading. The stability region, ideal strength, and potential bifurcation mode of those cubic crystals under loading are obtained using this theory. The results obtained are in good agreement with the results from the ab initio calculation or embedded atom method. The overall good quality of the results confirms the desired utility of this new approach to predict elastic stability and related properties of crystalline materials without involving intense computation.
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.
Efficient and robust feature extraction by maximum margin criterion.
Li, Haifeng; Jiang, Tao; Zhang, Keshu
2006-01-01
In pattern recognition, feature extraction techniques are widely employed to reduce the dimensionality of data and to enhance the discriminatory information. Principal component analysis (PCA) and linear discriminant analysis (LDA) are the two most popular linear dimensionality reduction methods. However, PCA is not very effective for the extraction of the most discriminant features, and LDA is not stable due to the small sample size problem. In this paper, we propose some new (linear and nonlinear) feature extractors based on maximum margin criterion (MMC). Geometrically, feature extractors based on MMC maximize the (average) margin between classes after dimensionality reduction. It is shown that MMC can represent class separability better than PCA. As a connection to LDA, we may also derive LDA from MMC by incorporating some constraints. By using some other constraints, we establish a new linear feature extractor that does not suffer from the small sample size problem, which is known to cause serious stability problems for LDA. The kernelized (nonlinear) counterpart of this linear feature extractor is also established in the paper. Our extensive experiments demonstrate that the new feature extractors are effective, stable, and efficient.
Robust principal component analysis based on maximum correntropy criterion.
He, Ran; Hu, Bao-Gang; Zheng, Wei-Shi; Kong, Xiang-Wei
2011-06-01
Principal component analysis (PCA) minimizes the mean square error (MSE) and is sensitive to outliers. In this paper, we present a new rotational-invariant PCA based on maximum correntropy criterion (MCC). A half-quadratic optimization algorithm is adopted to compute the correntropy objective. At each iteration, the complex optimization problem is reduced to a quadratic problem that can be efficiently solved by a standard optimization method. The proposed method exhibits the following benefits: 1) it is robust to outliers through the mechanism of MCC which can be more theoretically solid than a heuristic rule based on MSE; 2) it requires no assumption about the zero-mean of data for processing and can estimate data mean during optimization; and 3) its optimal solution consists of principal eigenvectors of a robust covariance matrix corresponding to the largest eigenvalues. In addition, kernel techniques are further introduced in the proposed method to deal with nonlinearly distributed data. Numerical results demonstrate that the proposed method can outperform robust rotational-invariant PCAs based on L(1) norm when outliers occur.
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.
A Topological Criterion for Filtering Information in Complex Brain Networks
Latora, Vito; Chavez, Mario
2017-01-01
In many biological systems, the network of interactions between the elements can only be inferred from experimental measurements. In neuroscience, non-invasive imaging tools are extensively used to derive either structural or functional brain networks in-vivo. As a result of the inference process, we obtain a matrix of values corresponding to a fully connected and weighted network. To turn this into a useful sparse network, thresholding is typically adopted to cancel a percentage of the weakest connections. The structural properties of the resulting network depend on how much of the inferred connectivity is eventually retained. However, how to objectively fix this threshold is still an open issue. We introduce a criterion, the efficiency cost optimization (ECO), to select a threshold based on the optimization of the trade-off between the efficiency of a network and its wiring cost. We prove analytically and we confirm through numerical simulations that the connection density maximizing this trade-off emphasizes the intrinsic properties of a given network, while preserving its sparsity. Moreover, this density threshold can be determined a-priori, since the number of connections to filter only depends on the network size according to a power-law. We validate this result on several brain networks, from micro- to macro-scales, obtained with different imaging modalities. Finally, we test the potential of ECO in discriminating brain states with respect to alternative filtering methods. ECO advances our ability to analyze and compare biological networks, inferred from experimental data, in a fast and principled way. PMID:28076353
A Topological Criterion for Filtering Information in Complex Brain Networks.
De Vico Fallani, Fabrizio; Latora, Vito; Chavez, Mario
2017-01-01
In many biological systems, the network of interactions between the elements can only be inferred from experimental measurements. In neuroscience, non-invasive imaging tools are extensively used to derive either structural or functional brain networks in-vivo. As a result of the inference process, we obtain a matrix of values corresponding to a fully connected and weighted network. To turn this into a useful sparse network, thresholding is typically adopted to cancel a percentage of the weakest connections. The structural properties of the resulting network depend on how much of the inferred connectivity is eventually retained. However, how to objectively fix this threshold is still an open issue. We introduce a criterion, the efficiency cost optimization (ECO), to select a threshold based on the optimization of the trade-off between the efficiency of a network and its wiring cost. We prove analytically and we confirm through numerical simulations that the connection density maximizing this trade-off emphasizes the intrinsic properties of a given network, while preserving its sparsity. Moreover, this density threshold can be determined a-priori, since the number of connections to filter only depends on the network size according to a power-law. We validate this result on several brain networks, from micro- to macro-scales, obtained with different imaging modalities. Finally, we test the potential of ECO in discriminating brain states with respect to alternative filtering methods. ECO advances our ability to analyze and compare biological networks, inferred from experimental data, in a fast and principled way.
A Validity-Based Model for the Evaluation of a Criterion-Referenced Test.
ERIC Educational Resources Information Center
Schattgen, Sharon; And Others
This paper describes a model for the evaluation and approval of a test battery for compliance with a midwestern state law mandating criterion-referenced testing of specific objectives. Standards specifying that the test scores must demonstrate content validity and criterion-related validity form the foundation of the model. The model also…
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…
Replacement Air Group Performance as a Criterion for Naval Aviation Training.
ERIC Educational Resources Information Center
Bale, Ronald M.; And Others
The current criterion for prediction of performance of student naval aviators is the dichotomy of success versus failure in undergraduate flight training. This criterion has enabled the naval air training command to make reasonable estimates of the probability of an applicant or student completing flight training. However, a costly attrition…
Educational Testing in America: What's Right, What's Wrong? A Criterion-Referenced Perspective.
ERIC Educational Resources Information Center
Popham, W. James
1993-01-01
Current successes and failures in U.S. educational measurement are reviewed, focusing on criterion-referenced testing. Pluses and minuses are listed for the following: (1) the move toward authentic assessment; (2) the dominance of criterion-referenced assessment; and (3) item response theory applications. Each area is a double-edged sword. (SLD)
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…
Diagnostics of the Properties of Steel Articles According to the Criterion of Microhardness
NASA Astrophysics Data System (ADS)
Astashchenko, V. I.; Shveev, A. I.; Shveeva, T. V.
2016-09-01
On the basis of metallographic monitoring of semimanufactured steel pieces and automobile parts, it is shown that prediction of the properties of articles on the basis of the criterion of microhardness of individual structural constituents and the difference in the values of the criterion represents an effective approach.
10 CFR 140.85 - Criterion II-Substantial damages to persons offsite or property offsite.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 10 Energy 2 2012-01-01 2012-01-01 false Criterion II-Substantial damages to persons offsite or property offsite. 140.85 Section 140.85 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) FINANCIAL PROTECTION REQUIREMENTS AND INDEMNITY AGREEMENTS Extraordinary Nuclear Occurrences § 140.85 Criterion...
A Graph Theoretic Criterion for Determining the Number of Clusters in a Data Set.
ERIC Educational Resources Information Center
Krolak-Schwerdt, Sabine; Eckes, Thomas
1992-01-01
Procedures for determining the number of clusters in a data set are explored. A proposed stopping rule, the GRAPH criterion, is compared to four stopping rules currently in use. The GRAPH criterion's mathematically attractive properties and utility in solving the number-of-clusters problem are demonstrated. (SLD)
Transformation of Both Predictor and Criterion Variables to a Simplified Regression Structure.
ERIC Educational Resources Information Center
Ping, Chieh-min; Tucker, Ledyard R.
Prediction for a number of criteria from a set of predictor variables in a system of regression equations is studied with the possibilities of linear transformations applied to both the criterion and predictor variables. Predictive composites representing a battery of predictor variables provide identical estimates of criterion scores as do the…
Problems in Criterion-Referenced Measurement. CSE Monograph Series in Evaluation, 3.
ERIC Educational Resources Information Center
Harris, Chester W., Ed.; And Others
Six essays on technical measurement problems in criterion referenced tests and four essays by psychometricians proposing solutions are presented: (1) "Criterion-Referenced Measurement" and Other Such Terms, by Marvin C. Alkin which is an overview of the first six papers; (2) Selecting Objectives and Generating Test Items for Objectives-Based…
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…
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…
The quest to find the plasma edge and discover a collisionally modified Bohm criterion
NASA Astrophysics Data System (ADS)
Franklin, R. N.; Franklin
2013-10-01
The concepts of `plasma edge' and `collisionally modified Bohm criterion' have occupied attention for many years since the publication of work by Bohm that gave rise to the Bohm criterion. He acknowledged that his description of the plasma-sheath transition was incomplete. We summarize work that shows that neither concept has precision, at the same time giving a critique.
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.
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:…
ERIC Educational Resources Information Center
Downing, Steven M.; Mehrens, William A.
Four criterion-referenced reliability coefficicents were compared to the Kuder-Richardson estimates and to each other. The Kuder-Richardson formulas 20 and 21, the Livingston, the Subkoviak and two Huynh coefficients were computed for a random sample of 33 criterion-referenced tests. The Subkoviak coefficient yielded the highest mean value;…
ERIC Educational Resources Information Center
Ding, Cody S.; Davison, Mark L.
2010-01-01
Akaike's information criterion is suggested as a tool for evaluating fit and dimensionality in metric multidimensional scaling that uses least squares methods of estimation. This criterion combines the least squares loss function with the number of estimated parameters. Numerical examples are presented. The results from analyses of both simulation…
ERIC Educational Resources Information Center
Alabama State Dept. of Education, Montgomery. Div. of Vocational Education.
Designed to provide guidance in the development of performance objectives and criterion-referenced measures, this booklet is intended for teachers, supervisory personnel, teacher trainers, and writers involved in developing performance-based instruction. To show the relationship of performance objectives and criterion-referenced measures to the…
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…
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
Oakland, Thomas
New strategies for evaluation criterion referenced measures (CRM) are discussed. These strategies examine the following issues: (1) the use of normed referenced measures (NRM) as CRM and then estimating the reliability and validity of such measures in terms of variance from an arbitrarily specified criterion score, (2) estimation of the…
The Testing of English as a Second/Foreign Language in the Criterion-Referenced Era.
ERIC Educational Resources Information Center
Davidson, Fred
In the assessment of second/foreign language proficiency, we are entering the era of criterion-referenced assessment as language learning is being recognized as an integrative, multifaceted construct. Norm-referenced measurement (NRM) is compared with criterion-referenced measurement (CRM). CRM is characterized by attention to skill, whereas NRM…
The Yeh-Stratton Criterion for Stress Concentrations on Fiber -Reinforced Composite Materials
NASA Technical Reports Server (NTRS)
Yeh, Hsieng-Yang
1996-01-01
The Yeh-Stratton criterion developed from a yielding criterion is modified to a generalized failure criterion and applied to fiber-reinforced composites with a central crack or a circular cutout under tensile loadings. The purpose of a material failure criterion is to establish a theoretical margin of safety and to be validated by experiments. It is necessary to obtain the crack tip stress field before a failure criterion of composite materials is applied. However, the crack tip stress field is complicated since there are numerous factors that influence the crack tip stress distribution. The understanding of the factors that contribute to crack tip stress field is of critical importance in analyzing composite laminates.
Barshan, Billur
2008-12-15
An objective error criterion is proposed for evaluating the accuracy of maps of unknown environments acquired by making range measurements with different sensing modalities and processing them with different techniques. The criterion can also be used for the assessment of goodness of fit of curves or shapes fitted to map points. A demonstrative example from ultrasonic mapping is given based on experimentally acquired time-of-flight measurements and compared with a very accurate laser map, considered as absolute reference. The results of the proposed criterion are compared with the Hausdorff metric and the median error criterion results. The error criterion is sufficiently general and flexible that it can be applied to discrete point maps acquired with other mapping techniques and sensing modalities as well.
Laboratory study on new cathodic protection criterion proposed for prestressed concrete
Wagner, J. Jr.; Funahashi, M.
1994-12-31
Bazzoni and Lazzari have proposed a new criterion for the cathodic protection of prestressed concrete. The criterion is based on the use of mixed metal-oxide-activated anodes which exhibit a stable polarized potential over a wide range of current densities when embedded in concrete. The criterion proposes that a ``safe`` anode/structure feeding voltage can be calculated that will both provide corrosion control in the area covered by the anode system and will prevent the steel reinforcement potential reaching values where hydrogen ions can be reduced to hydrogen and the consequent possibility of embrittlement of high strength prestressing members. This paper describes a laboratory study made to examine the validity of the proposed criterion. The results of the study appear to support criterion as both safe and effective for new prestressed concrete structures and possibly for existing structures as well.
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.
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
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.
Ancients' Criterion of Earliest Visibility of the Lunar Crescent - how Good is it
NASA Astrophysics Data System (ADS)
Ilyas, M.
Earliest visibility of the lunar crescent is an important calendrical element. It was needed in all early calendars and remains in use on some lunar calendars today. An astronomical criterion of earliest lunar visibility was therefore evolved quite early, using observations, right from the Babylonian era. Recently, an improved and comprehensive global criterion of earliest visibility, developed by the author, has been used to generate an extensive inverted moonset lag data set. These data, as a function of latitude and season, all for the first time provide a useful comparison with the simple ancient criterion.
Latent Class Analysis of Incomplete Data via an Entropy-Based Criterion.
Larose, Chantal; Harel, Ofer; Kordas, Katarzyna; Dey, Dipak K
2016-09-01
Latent class analysis is used to group categorical data into classes via a probability model. Model selection criteria then judge how well the model fits the data. When addressing incomplete data, the current methodology restricts the imputation to a single, pre-specified number of classes. We seek to develop an entropy-based model selection criterion that does not restrict the imputation to one number of clusters. Simulations show the new criterion performing well against the current standards of AIC and BIC, while a family studies application demonstrates how the criterion provides more detailed and useful results than AIC and BIC.
NASA Astrophysics Data System (ADS)
Li, Wenlin; Li, Chong; Song, Heshan
2015-02-01
We propose a quantitative criterion to determine whether the coupled quantum systems can achieve complete synchronization or phase synchronization in the process of analyzing quantum synchronization. Adopting the criterion, we discuss the quantum synchronization effects between optomechanical systems and find that the error between the systems and the fluctuation of error is sensitive to coupling intensity by calculating the largest Lyapunov exponent of the model and quantum fluctuation, respectively. By taking the appropriate coupling intensity, we can control quantum synchronization even under different logical relationships between switches. Finally, we simulate the dynamical evolution of the system to verify the quantum synchronization criterion and to show the ability of synchronization control.
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.
Yeh-Stratton Criterion for Stress Concentrations on Fiber-Reinforced Composite Materials
NASA Technical Reports Server (NTRS)
Yeh, Hsien-Yang; Richards, W. Lance
1996-01-01
This study investigated the Yeh-Stratton Failure Criterion with the stress concentrations on fiber-reinforced composites materials under tensile stresses. The Yeh-Stratton Failure Criterion was developed from the initial yielding of materials based on macromechanics. To investigate this criterion, the influence of the materials anisotropic properties and far field loading on the composite materials with central hole and normal crack were studied. Special emphasis was placed on defining the crack tip stress fields and their applications. The study of Yeh-Stratton criterion for damage zone stress fields on fiber-reinforced composites under tensile loading was compared with several fracture criteria; Tsai-Wu Theory, Hoffman Theory, Fischer Theory, and Cowin Theory. Theoretical predictions from these criteria are examined using experimental results.
A 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
Focus detection criterion for refocusing in multi-wavelength digital holography.
Xu, Li; Mater, Mike; Ni, Jun
2011-08-01
The majority of focus detection criteria reported is based on amplitude contrast. Due to phase wrapping, phase contrast was previously reported unsuitable for focus finding tasks. By taking the advantage of multi-wavelength digital holography, we propose a new focus detection criterion based on phase contrast. Experimental results are presented to prove the feasibility of the developed criterion. Possible applications of the developed technology include inspecting machined surfaces in the auto industry.
The Beale-Kato-Majda Criterion for the 3D Magneto-Hydrodynamics Equations
NASA Astrophysics Data System (ADS)
Chen, Qionglei; Miao, Changxing; Zhang, Zhifei
2007-11-01
We study the blow-up criterion of smooth solutions to the 3D MHD equations. By means of the Littlewood-Paley decomposition, we prove a Beale-Kato-Majda type blow-up criterion of smooth solutions via the vorticity of velocity only, namely sup_{jinmathbb{Z}}int_0^T\\|Δ_j(nabla× u)\\|_infty dt, where Δ j is the frequency localization operator in the Littlewood-Paley decomposition.
A texture-analysis-based design method for self-adaptive focus criterion function.
Liang, Q; Qu, Y F
2012-05-01
Autofocusing (AF) criterion functions are critical to the performance of a passive autofocusing system in automatic video microscopy. Most of the autofocusing criterion functions proposed are dependent on the imaging system and image captured by the objective being focused or ranged. This dependence destabilizes the performance of the system when the criterion functions are applied to objectives with different characteristics. In this paper, a new design method for autofocusing criterion functions is introduced. This method enables the system to have the ability to tell the texture directional information of the objective. Based on this information, the optimal focus criterion function specific to one texture direction is designed, voiding blindly using autofocusing functions which cannot perform well when applied to the certain surface and can even lead to failure of the whole process. In this way, we improved the self-adaptability, robustness, reliability and focusing accuracy of the algorithm. First, the grey-level co-occurrence matrices of real-time images are calculated in four directions. Next, the contrast values of the four matrices are computed and then compared. The result reflects the directional information of the measured objective surfaces. Finally, with the directional information, an adaptive criterion function is constructed. To demonstrate the effectiveness of the new focus algorithm, we conducted experiments on different texture surfaces and compared the results with those obtained by existing algorithms. The proposed algorithm excellently performs with different measured objectives.
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 comparison of criterion standard methods to diagnose acute heart failure.
Collins, Sean P; Lindsell, Christopher J; Yealy, Donald M; Maron, David J; Naftilan, Allen J; McPherson, John A; Storrow, Alan B
2012-01-01
The authors sought to compare and contrast the clinical criterion standards currently used in a cohort of emergency department (ED) patients to diagnose acute heart failure syndromes (AHFS). In a prospective observational study of patients with signs and symptoms of AHFS, 3 criterion standards were examined: (1) the treating ED physician's diagnosis; (2) the hospital discharge diagnosis; and (3) a diagnosis based on medical record review by a panel of cardiologists. Using Cohen's kappa (κ) coefficient, the authors assessed agreement and then compared the different standards by repeatedly setting one as the criterion standard and the other two as index tests. A total of 483 patients were enrolled. Across all criterion standards, patients with AHFS were more likely to have a history of AHFS, congestion on physical examination and chest radiography, and elevated natriuretic peptide levels than those without AHFS. The standards agreed well (cardiology review vs hospital discharge diagnosis, κ=0.74; cardiology review vs ED diagnosis, κ=0.66; ED diagnosis vs hospital discharge diagnosis κ=0.59). Each method had similar sensitivity but differing specificities. Different criterion standards identify different patients from among those being evaluated for AHFS. Researchers should consider this when choosing between the various criterion standard approaches when evaluating new index tests.
A multiple maximum scatter difference discriminant criterion for facial feature extraction.
Song, Fengxi; Zhang, David; Mei, Dayong; Guo, Zhongwei
2007-12-01
Maximum scatter difference (MSD) discriminant criterion was a recently presented binary discriminant criterion for pattern classification that utilizes the generalized scatter difference rather than the generalized Rayleigh quotient as a class separability measure, thereby avoiding the singularity problem when addressing small-sample-size problems. MSD classifiers based on this criterion have been quite effective on face-recognition tasks, but as they are binary classifiers, they are not as efficient on large-scale classification tasks. To address the problem, this paper generalizes the classification-oriented binary criterion to its multiple counterpart--multiple MSD (MMSD) discriminant criterion for facial feature extraction. The MMSD feature-extraction method, which is based on this novel discriminant criterion, is a new subspace-based feature-extraction method. Unlike most other subspace-based feature-extraction methods, the MMSD computes its discriminant vectors from both the range of the between-class scatter matrix and the null space of the within-class scatter matrix. The MMSD is theoretically elegant and easy to calculate. Extensive experimental studies conducted on the benchmark database, FERET, show that the MMSD out-performs state-of-the-art facial feature-extraction methods such as null space method, direct linear discriminant analysis (LDA), eigenface, Fisherface, and complete LDA.
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
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.
Mazel, Vincent; Diarra, Harona; Busignies, Virginie; Tchoreloff, Pierre
2014-08-15
Several tests can be used to study the strength of pharmaceutical tablets. Equations exist in the literature to transform the failure force measured into a failure stress which can be considered as a characteristic of the strength of the material. For each failure test, the stress state at failure is different, and as a consequence, the failure stresses obtained are also different. It would thus be interesting to find a failure criterion to unify the different results. In this study four different tests were performed on pharmaceutical compacts of various densities: diametral compression, three-point flexure, biaxial flexure and uniaxial compressive tests. The Drucker-Prager criterion was tested as a possible fracture envelope. The results showed that this criterion is well suited to explain the failures obtained by diametral compression, three-point flexure and biaxial flexure. Nevertheless, for the uniaxial compressive test, the use of this criterion led to a significative underestimation of the experimental value of the failure stress. As a consequence, the Drucker-Prager criterion must be used with caution and is not able to explain all the failures that can occur in a pharmaceutical compact.
New Criterion for Evaluating the Peak Shear Strength of Rock Joints Under Different Contact States
NASA Astrophysics Data System (ADS)
Tang, Zhi Cheng; Wong, Louis Ngai Yuen
2016-04-01
In practice, the peak shear strength of rock joints is not dictated only by the surface roughness, but also the degree of matching between the joint surfaces. The latter is due to alteration/dislocation caused by external factors, such as the vibration due to nearby blasting, excavation or earthquake. In the present study, the peak shear strengths of rock joints under different contact states are investigated by direct shear test using artificial rock joints. The rock joints under different contact states are modeled by imposing varying magnitude of horizontal dislocation along the shear direction between the upper and lower rock blocks. The peak shear strength was found to decrease with increasing dislocation. A new empirical shear strength criterion is put forward to capture the peak shear strength of un-matching rock joints as an extension of a previously published peak shear strength criterion for matching rock joints by the first author and his co-workers. In the present proposed criterion, a new joint contact state coefficient, which is a function of the normalized dislocation and the quantified three-dimensional roughness metric of joint surface, is proposed. The good agreement between calculated values and test results indicates that the proposed criterion is capable of estimating the peak shear strength of rock joints under different contact states. The proposed criterion is expressed in a quantitative way and the required parameters can be easily determined in the laboratory.
NASA Astrophysics Data System (ADS)
Li, Chuan; Liang, Ming; Wang, Tianyang
2015-12-01
The defective bearing signatures can be detected by resonance demodulation of the vibration signals. The decision of the bearing fault detection largely depends on the quality of the identified resonant frequency band. Two key issues in locating the resonance frequency band are the proper segmentation of the frequency spectrum of interest and the criterion used to guide the search for the resonance band. To deal with the two issues, this paper proposes a criterion fusion approach to guide the spectral segmentation process. With the proposed approach, the frequency spectrum of the bearing signal is first divided into initial fine segments which are then adaptively merged into different subsets using an enhanced bottom-up segmentation technique. To guide the spectral segmentation and merging process, three commonly used criteria, i.e., kurtosis, smoothness index and crest factor are fused into a synthesized cost function using an entropy-based method. The final frequency band delivered by this approach has a good coverage of the resonant band and is then used to demodulate bearing signals. Both simulated and experimental signals have been employed to evaluate the proposed approach, which has also been compared to single-criterion methods. The comparison indicates that the fused criterion yields better results than those from the single-criterion.
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.
PTSD's risky behavior criterion: Relation with DSM-5 PTSD symptom clusters and psychopathology.
Contractor, Ateka A; Weiss, Nicole H; Dranger, Paula; Ruggero, Camilo; Armour, Cherie
2017-03-06
A new symptom criterion of reckless and self-destructive behaviors (E2) was recently added to posttraumatic stress disorder's (PTSD) diagnostic criteria in DSM-5, which is unsurprising given the well-established relation between PTSD and risky behaviors. Researchers have questioned the significance and incremental validity of this symptom criterion within PTSD's symptomatology. Unprecedented to our knowledge, we aim to compare trauma-exposed groups differing on their endorsement status of the risky behavior symptom on several psychopathology constructs (PTSD, depression, distress tolerance, rumination, anger). The sample included 123 trauma-exposed participants seeking mental health treatment (M age=35.70; 68.30% female) who completed self-report questionnaires assessing PTSD symptoms, depression, rumination, distress tolerance, and anger. Results of independent samples t-tests indicated that participants who endorsed the E2 criterion at a clinically significant level reported significantly greater PTSD subscale severity; depression severity; rumination facets of repetitive thoughts, counterfactual thinking, and problem-focused thinking; and anger reactions; and significantly less absorption and regulation (distress tolerance facets) compared to participants who did not endorse the E2 criterion at a clinically significant level. Results indicate the utility of the E2 criterion in identifying trauma-exposed individual with greater posttraumatic distress, and emphasize the importance of targeting such behaviors in treatment.
Contribution of criterion A2 to PTSD screening in the presence of traumatic events.
Pereda, Noemí; Forero, Carlos G
2012-10-01
Criterion A2 according to the Diagnostic and Statistical Manual of Mental Disorders (4(th) ed.; DSM-IV; American Psychiatric Association [APA], 1994) for posttraumatic stress disorder (PTSD) aims to assess the individual's subjective appraisal of an event, but it has been claimed that it might not be sufficiently specific for diagnostic purposes. We analyse the contribution of Criterion A2 and DSM-IV criteria to detect PTSD for the most distressing life events experienced by our subjects. Young adults (N = 1,033) reported their most distressing life events, together with PTSD criteria (Criteria A2, B, C, D, E, and F). PTSD prevalence and criterion specificity and agreement with probable diagnoses were estimated. Our results indicate 80.30% of the individuals experienced traumatic events and met one or more PTSD criteria; 13.22% cases received a positive diagnosis of PTSD. Criterion A2 showed poor agreement with the final probable PTSD diagnosis (correlation with PTSD .13, specificity = .10); excluding it from PTSD diagnosis did not the change the estimated disorder prevalence significantly. Based on these findings it appears that Criterion A2 is scarcely specific and provides little information to confirm a probable PTSD case.
Tascon, Marcos; Benavente, Fernando; Castells, Cecilia B; Gagliardi, Leonardo G
2016-08-19
In capillary electrophoresis (CE), resolution (Rs) and selectivity (α) are criteria often used in practice to optimize separations. Nevertheless, when these and other proposed parameters are considered as an elementary criterion for optimization by mathematical maximization, certain issues and inconsistencies appear. In the present work we analyzed the pros and cons of using these parameters as elementary criteria for mathematical optimization of capillary electrophoretic separations. We characterized the requirements of an ideal criterion to qualify separations within the framework of mathematical optimizations and, accordingly, propose: -1- a new elementary criterion (t') and -2- a method to extend this elementary criterion to compose a global function that simultaneously qualifies many different aspects, also called multicriteria optimization function (MCOF). In order to demonstrate this new concept, we employed a group of six alkaloids with closely related structures (harmine, harmaline, harmol, harmalol, harmane and norharmane). On the basis of this system, we present a critical comparison between the new optimization criterion t' and the former elementary criteria. Finally, aimed at validating the proposed methods, we composed an MCOF in which the capillary-electrophoretic separation of the six model compounds is mathematically optimized as a function of pH as the unique variable. Experimental results subsequently confirmed the accuracy of the model.
Formability Prediction of Advanced High Strength Steel with a New Ductile Fracture Criterion
NASA Astrophysics Data System (ADS)
Lou, Yanshan; Lim, Sungjun; Huh, Jeehyang; Huh, Hoon
2011-08-01
A ductile fracture criterion is newly proposed to accurately predict forming limit diagrams (FLD) of sheet metals. The new ductile fracture criterion is based on the effect of the non-dimensional stress triaxiality, the stress concentration factor and the effective plastic strain on the nucleation, growth and coalescence of voids. The new ductile fracture criterion has been applied to estimate the formability of four kind advanced high strength steels (AHSS): DP780, DP980, TRIP590, and TWIP980. FLDs predicted are compared with experimental results and those predicted by other ductile fracture criteria. The comparison demonstrates that FLDs predicted by the new ductile fracture criterion are in better agreement with experimental FLDs than those predicted by other ductile fracture criteria. The better agreement of FLDs predicted by the new ductile fracture criterion is because conventional ductile fracture criteria were proposed for fracture prediction in bulk metal forming while the new one is proposed to predict the onset of fracture in sheet metal forming processes.
Prediction of Shrinkage Pore Volume Fraction Using a Dimensionless Niyama Criterion
NASA Astrophysics Data System (ADS)
Carlson, Kent D.; Beckermann, Christoph
2009-01-01
A method is presented to use a dimensionless form of the well-known Niyama criterion to directly predict the amount of shrinkage porosity that forms during solidification of metal alloy castings. The main advancement offered by this method is that it avoids the need to know the threshold Niyama value below which shrinkage porosity forms; such threshold values are generally unknown and alloy dependent. The dimensionless criterion accounts for both the local thermal conditions (as in the original Niyama criterion) and the properties and solidification characteristics of the alloy. Once a dimensionless Niyama criterion value is obtained from casting simulation results, the corresponding shrinkage pore volume fraction can be determined knowing only the solid fraction-temperature curve and the total solidification shrinkage of the alloy. Curves providing the shrinkage pore volume percentage as a function of the dimensionless Niyama criterion are given for WCB steel, aluminum alloy A356, and magnesium alloy AZ91D. The present method is used in a general-purpose casting simulation software package to predict shrinkage porosity in three-dimensional (3-D) castings. Comparisons between simulated and experimental shrinkage porosity results for a WCB steel plate casting demonstrate that this method can reasonably predict shrinkage. Additional simulations for magnesium alloy AZ91D illustrate that this method is applicable to a wide variety of alloys and casting conditions.
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)
Pommatau, Gilles
2014-06-01
The present paper deals with the industrial application, via a software developed by Thales Alenia Space, of a new failure criterion named "Tsai-Hill equivalent criterion" for composite structural parts of satellites. The first part of the paper briefly describes the main hypothesis and the possibilities in terms of failure analysis of the software. The second parts reminds the quadratic and conservative nature of the new failure criterion, already presented in ESA conference in a previous paper. The third part presents the statistical calculation possibilities of the software, and the associated sensitivity analysis, via results obtained on different composites. Then a methodology, proposed to customers and agencies, is presented with its limitations and advantages. It is then conclude that this methodology is an efficient industrial way to perform mechanical analysis on quasi-isotropic composite parts.
A semi-empirical stability criterion for real planetary systems with eccentric orbits
NASA Astrophysics Data System (ADS)
Giuppone, C. A.; Morais, M. H. M.; Correia, A. C. M.
2013-12-01
We test a crossing orbit stability criterion for eccentric planetary systems, based on Wisdom's criterion of first-order mean motion resonance overlap. We show that this criterion fits the stability regions in real exoplanet systems quite well. In addition, we show that elliptical orbits can remain stable even for regions where the apocentre distance of the inner orbit is larger than the pericentre distance of the outer orbit, as long as the initial orbits are aligned. The analytical expressions provided here can be used to put rapid constraints on the stability zones of multiplanetary systems. As a byproduct of this research, we further show that the amplitude variations of the eccentricity can be used as a fast-computing stability indicator.
The criterion-calibration model of cue interaction in contingency judgments.
Hannah, Samuel D; Allan, Lorraine G
2011-05-01
Siegel, Allan, Hannah, and Crump (2009) demonstrated that cue interaction effects in human contingency judgments reflect processing that occurs after the acquisition of information. This finding is in conflict with a broad class of theories. We present a new postacquisition model, the criterion-calibration model, that describes cue interaction effects as involving shifts in a report criterion. The model accounts for the Siegel et al. data and outperforms the only other postacquisition model of cue interaction, Stout and Miller's (2007) SOCR model. We present new data from an experiment designed to evaluate a prediction of the two models regarding reciprocal cue interaction effects. The new data provide further support for the criterion-calibration model.
Application of melt ejection criterion in simulation of micromachining with laser
NASA Astrophysics Data System (ADS)
Semak, Vladimir V.; Schriempf, J. T.; Knorovsky, G. A.; MacCallum, D. O.
2003-07-01
The theoretical criterion defining the threshold pulse energy and beam intensity required for melt ejection is proposed. The results of numerical simulation present dependencies of the threshold pulse energy and beam intensity as functions of laser pulse duration and beam radius. The experimental verification of proposed criterion is described and the comparison of theoretical predictions and measurements is presented. The criterion is applied for simulation of laser drilling metal foil with thickness in the range 25 μm - 125 μm using laser beam with 12 μm beam radius and pulse durations 10 ns and 100 ns. The computational results are used to interpret the results of experimental study of laser drilling of 125 μm aluminum foil using a single mode beam of a XeCl laser performed at the Nederlands Centrum voor Laser Research (NCLR) and the University of Twente. Additional results on Nd:YAG spot welds in pure Ni are also presented.
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 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.
An error criterion for the pointing of axially symmetric spacecraft payloads
NASA Astrophysics Data System (ADS)
Coffey, T. C.
1983-12-01
In connection with approaches to minimize the pointing error of the actual orientation of a spacecraft antenna or sensor with respect to the direction of interest, most investigators choose to structure their analysis around one of three conventional measures of the pointing error covariance matrix. The considered investigation is concerned with the development of an error criterion which is 'tailor-made' to the pointing application. The error criterion developed takes special account of the fact that most spacecraft components which require pointing are symmetrical about the boresight axis. This new criterion J(Phi) does not penalize rotation errors about the boresight axis. Moreover, J(Phi) is a measure of the statistical expectation of the mean-square boresight deflection error for that pointing direction which maximizes this error, given a statistically specified set of spacecraft attitude errors. The cost function J(Phi) is compared and related to three more commonly used
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
2016-01-01
In PID controller design, an optimization algorithm is commonly employed to search for the optimal controller parameters. The optimization algorithm is based on a specific performance criterion which is defined by an objective or cost function. To this end, different objective functions have been proposed in the literature to optimize the response of the controlled system. These functions include numerous weighted time and frequency domain variables. However, for an optimum desired response it is difficult to select the appropriate objective function or identify the best weight values required to optimize the PID controller design. This paper presents a new time domain performance criterion based on the multiobjective Pareto front solutions. The proposed objective function is tested in the PID controller design for an automatic voltage regulator system (AVR) application using particle swarm optimization algorithm. Simulation results show that the proposed performance criterion can highly improve the PID tuning optimization in comparison with traditional objective functions.
Mean-square convergence analysis of ADALINE training with minimum error entropy criterion.
Chen, Badong; Zhu, Yu; Hu, Jinchun
2010-07-01
Recently, the minimum error entropy (MEE) criterion has been used as an information theoretic alternative to traditional mean-square error criterion in supervised learning systems. MEE yields nonquadratic, nonconvex performance surface even for adaptive linear neuron (ADALINE) training, which complicates the theoretical analysis of the method. In this paper, we develop a unified approach for mean-square convergence analysis for ADALINE training under MEE criterion. The weight update equation is formulated in the form of block-data. Based on a block version of energy conservation relation, and under several assumptions, we carry out the mean-square convergence analysis of this class of adaptation algorithm, including mean-square stability, mean-square evolution (transient behavior) and the mean-square steady-state performance. Simulation experimental results agree with the theoretical predictions very well.
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
Fenech, C M; Keaveny, T M
1999-08-01
In a long-term effort to develop a complete multi-axial failure criterion for human trabecular bone, the overall goal of this study was to compare the ability of a simple cellular solid mechanistic criterion versus the Tsai-Wu, Principal Strain, and von Mises phenomenological criteria--all normalized to minimize effects of interspecimen heterogeneity of strength--to predict the on-axis axial-shear failure properties of bovine trabecular bone. The Cellular Solid criterion that was developed here assumed that vertical trabeculae failed due to a linear superposition of axial compression/tension and bending stresses, induced by the apparent level axial and shear loading, respectively. Twenty-seven bovine tibial trabecular bone specimens were destructively tested on-axis without end artifacts, loaded either in combined tension-torsion (n = 10), compression-torsion (n = 11), or uniaxially (n = 6). For compression-shear, the mean (+/- S.D.) percentage errors between measured values and criterion predictions were 7.7 +/- 12.6 percent, 19.7 +/- 23.2 percent, 22.8 +/- 18.9 percent, and 82.4 +/- 64.5 percent for the Cellular Solid, Tsai-Wu, Principal Strain, and von Mises criteria, respectively; corresponding mean errors for tension-shear were -5.2 +/- 11.8 percent, 14.3 +/- 12.5 percent, 6.9 +/- 7.6 percent, and 57.7 +/- 46.3 percent. Statistical analysis indicated that the Cellular Solid criterion was the best performer for compression-shear, and performed as well as the Principal Strain criterion for tension-shear. These data should substantially improve the ability to predict axial-shear failure of dense trabecular bone. More importantly, the results firmly establish the importance of cellular solid analysis for understanding and predicting the multiaxial failure behavior of trabecular bone.
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.
NASA Astrophysics Data System (ADS)
Fang, L.; Sun, X. Y.; Liu, Y. W.
2016-12-01
In order to shed light on understanding the subgrid-scale (SGS) modelling methodology, we analyze and define the concepts of assumption and restriction in the modelling procedure, then show by a generalized derivation that if there are multiple stationary restrictions in a modelling, the corresponding assumption function must satisfy a criterion of orthogonality. Numerical tests using one-dimensional nonlinear advection equation are performed to validate this criterion. This study is expected to inspire future research on generally guiding the SGS modelling methodology.
Geometry of the transition criterion of shock wave reflection over a wedge
NASA Astrophysics Data System (ADS)
Cui, T.; Jiao, X.; Yu, D.
2015-01-01
The hysteresis phenomena of shock wave reflection observed during recent numerical and experimental investigations are analyzed in this paper using dynamical system theory. It is found through the analysis that the geometry of the transition criterion of shock wave reflection over a wedge has the shape of a butterfly. Knowledge of the geometry can provide important information on the hysteresis behavior of shock wave reflection. The geometry of the transition criterion can be used not only for the explanation of already known hysteresis behavior of shock wave reflection, but also for the prediction of novel hysteresis phenomena.
Network-based criterion for the success of cooperation in an evolutionary prisoner's dilemma.
Devlin, Stephen; Treloar, Thomas
2012-08-01
We consider an evolutionary prisoner's dilemma on a random network. We introduce a simple quantitative network-based parameter and show that it effectively predicts the success of cooperation in simulations on the network. The criterion is shown to be accurate on a variety of networks with degree distributions ranging from regular to Poisson to scale free. The parameter allows for comparisons of random networks regardless of their underlying topology. Finally, we draw analogies between the criterion for the success of cooperation introduced here and existing criteria in other contexts.
NASA Astrophysics Data System (ADS)
Gu, Anhui; Li, Yangrong
The paper is devoted to establishing a combination of sufficient criterion for the existence and upper semi-continuity of random attractors for stochastic lattice dynamical systems. By relying on a family of random systems itself, we first set up the abstract result when it is convergent, uniformly absorbing and uniformly random when asymptotically null in the phase space. Then we apply the results to the second-order lattice dynamical system driven by multiplicative white noise. It is indicated that the criterion depending on the dynamical system itself seems more applicable than the existing ones to lattice differential models.
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.
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.
1978-01-01
mve405b 8.329 1.991 10 0.7208 70 mve405c 9.087 1.222 10 0.4934 69 22 In classical test theory,0( 21 ( Kuder - Richardson )) is always smaller than or...Therefore, it is important and necessary to explore reliable methods that will help to improve the quality of CAI lessons. 2 CRITERION-REFERENCED TEST ...referenced testing has gained much attention from educational measurement and testing specialists in recent years. The object of criterion-referenced
Distribution of sea wave heights: Effects of a new criterion of defining discrete waves
Pires-Silva, A.A.; Medina, J.R.
1996-12-31
Wind-generated surface gravity wave heights and periods are non-observable variables. Notwithstanding, their role in sea environment characterization and consequently in ocean and coastal engineering design criteria is crucial. A new criterion of defining discrete waves from sea surface elevation time series, called orbital criterion, is applied to wave rider buoys records measured off the west coast of Portugal. The method uses the Hilbert Transform and the representation of the time series in the complex plane. Statistics and distributions of wave heights estimated with z-u-c and orbital criteria are employed in assessing the influence of the discretization criteria on the statistical characterization of random waves.
Brain death is not death: a critique of the concept, criterion, and tests of brain death.
Joffe, Ari R
2009-01-01
This paper suggests that there are insurmountable problems for brain death as a criterion of death. The following are argued: (1) brain death does not meet an accepted concept of death, and is not the loss of integration of the organism as a whole; (2) brain death does not meet the criterion of brain death itself; brain death is not the irreversible loss of all critical functions of the entire brain; and (3) brain death may, however rarely, be reversible. I conclude that brain death, while a devastating neurological state with a dismal prognosis, is not death.
NASA Astrophysics Data System (ADS)
Wang, Cong; Shang, De-Guang; Wang, Xiao-Wei
2015-02-01
An improved high-cycle multiaxial fatigue criterion based on the critical plane was proposed in this paper. The critical plane was defined as the plane of maximum shear stress (MSS) in the proposed multiaxial fatigue criterion, which is different from the traditional critical plane based on the MSS amplitude. The proposed criterion was extended as a fatigue life prediction model that can be applicable for ductile and brittle materials. The fatigue life prediction model based on the proposed high-cycle multiaxial fatigue criterion was validated with experimental results obtained from the test of 7075-T651 aluminum alloy and some references.
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…
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…
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…
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…
Comparing Four Estimates of the Criterion-Referenced Standard for a Written Test.
ERIC Educational Resources Information Center
Hughes, Francis P.
Four procedures were used to estimate a criterion-referenced standard for a multiple-choice examination developed by the National Board of Medical Examiners (NBME). Two experimental procedures, the NBME method and a modification of the Guerin method, and the Angoff and Ebel procedures were evaluated on the consistency of the estimates they…
ERIC Educational Resources Information Center
Francis, Alexandria S.; Holmes, Susan E.
Discrepancies among the standards produced by different criterion-referenced standard-setting techniques may be the result of a failure to adequately define the minimally competent candidate. Current research in this area is reviewed in terms of three categories: studies in which no formal assistance in conceptualization is given to judges,…
The Law Encounter Severity Scale (LESS): A Criterion for Criminal Behavior and Recidivism.
ERIC Educational Resources Information Center
Witherspoon, A. D.; And Others
Followup studies of released offenders in the community have frequently provided poor indices of recidivism because of their failure to discriminate between different kinds of violations and adjustment to the community. To develop a new criterion for measuring recidivism, information on the postrelease behavior of 142 adult male felons was…
The 3rd National Assessment of Reading and Literature Versus Norm- and Criterion-Referenced Testing.
ERIC Educational Resources Information Center
Petrosky, Anthony R.
In discussing the third national assessment of reading and literature, four major points can be made. First, norm-referenced tests and criterion-referenced tests ignore serious ethical and measurement problems, namely, we don't know enough about individual differences to do such testing and the outcome, social class tracking, is ethically…
NASA Astrophysics Data System (ADS)
Leslie-Pelecky, D.; Hehn, J. G.
2005-12-01
Community attitudes and outcomes regarding NSF'{s} broader impacts criterion could be improved significantly by emphasizing the motivation for implementing this requirement and the potential benefits to the research community, and achieving more consistent application of the criterion by improving proposer, reviewer and program officer understanding of the criterion. An organized and easily accessible '{}Toolbox'{} for broader impacts activities would help researchers develop and evaluate effective activities by building on the existing knowledge base. Institution-centered (disciplinary societies, colleges and universities, research centers, etc.) infrastructure can be an outstanding resource for assisting researchers in fulfilling the broader impacts criterion. These organizations leverage existing programs and experience, and have an important role as bridges between researchers and the results of discipline-based education research. The professionals directing these organizations are valuable resources and should be encouraged to build networks to share information and ideas. These statements represent outcomes of a workshop held in May 2005 supported by the Office of Multidisciplinary Activities of NSF/MPS. Action items developed from this workshop will be presented to stimulate questions and discussion.
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...
A More Practical Pedagogical Ideal: Searching for a Criterion of Deweyan Growth
ERIC Educational Resources Information Center
Ralston, Shane Jesse
2011-01-01
When Dewey scholars and educational theorists appeal to the value of educative growth, what exactly do they mean? Is an individual's growth contingent on receiving a formal education? Is growth too abstract a goal for educators to pursue? Richard Rorty contended that the request for a "criterion of growth" is a mistake made by John Dewey's…
ERIC Educational Resources Information Center
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…
A Cross-Validation of MMPI Scales of Aggression on Male Criminal Criterion Groups
ERIC Educational Resources Information Center
Deiker, Thomas E.
1974-01-01
The 13 basic Minnesota Multiphasic Personality Inventory (MMPI) scales, 21 experimental scales of hostility and control, and four response-bias scales are cross-validated on 168 male criminals assigned to four aggressive criterion groups (nonviolent, threat, battery, and homicide). (Author)
A Study of the Criterion Validity of the Mattis Dementia Rating Scale.
ERIC Educational Resources Information Center
Fernandez, Alberto Luis; Scheffel, Debora L.
2003-01-01
Evaluated the criterion validity of the Mattis Dementia Rating Scale (S. Mattis, 1988) with a concurrent study to obtain a cut-off score for an Argentinean population by administering a battery of tests to 60 memory disorder patients. Findings demonstrate high convergent validity with another measure and show an appropriate cut score for use with…
ERIC Educational Resources Information Center
Hopkins, Mary A.; Brock, Robert J.
Described in the discussion draft is a performance based criterion referenced curriculum for teaching vocational skills to trainable mentally retarded (TMR) students which was developed jointly by the University of Wisconsin at Stout and the Menomonie Public School Administration. Explained in the introduction are three evaluation inventories in…
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…
1980-06-01
science research institute RESEARCH REPORT EVALUATING CREDIT APPLICATIONS: A Z’ VALIDATION OF MULTIATTRIBUTE UTILITY TECHNIQUES AGAINST A REAL WORLD...8217_, ", ’- .’.- .. .- ... . .. ,-*,. . .. EVALUATING CREDIT APPLICATIONS: A VALIDATION OF MULTIATTRIBUTE UTILITY TECHNIQUES AGAINST A REAL WORLD CRITERION...validation of multiattribute utility elicitation techniques. The techniques tested were the Holistic Orthogonal Parameter Estimation (HOPE) technique
Soliton stability criterion for generalized nonlinear Schrödinger equations
NASA Astrophysics Data System (ADS)
Quintero, Niurka R.; Mertens, Franz G.; Bishop, A. R.
2015-01-01
A stability criterion for solitons of the driven nonlinear Schrödinger equation (NLSE) has been conjectured. The criterion states that p'(v ) <0 is a sufficient condition for instability, while p'(v ) >0 is a necessary condition for stability; here, v is the soliton velocity and p =P /N , where P and N are the soliton momentum and norm, respectively. To date, the curve p (v ) was calculated approximately by a collective coordinate theory, and the criterion was confirmed by simulations. The goal of this paper is to calculate p (v ) exactly for several classes and cases of the generalized NLSE: a soliton moving in a real potential, in particular a time-dependent ramp potential, and a time-dependent confining quadratic potential, where the nonlinearity in the NLSE also has a time-dependent coefficient. Moreover, we investigate a logarithmic and a cubic NLSE with a time-independent quadratic potential well. In the latter case, there is a bisoliton solution that consists of two solitons with asymmetric shapes, forming a bound state in which the shapes and the separation distance oscillate. Finally, we consider a cubic NLSE with parametric driving. In all cases, the p (v ) curve is calculated either analytically or numerically, and the stability criterion is confirmed.
NASA Astrophysics Data System (ADS)
Mertens, Franz G.; Quintero, Niurka R.; Barashenkov, I. V.; Bishop, A. R.
2011-08-01
We investigate the dynamics of traveling oscillating solitons of the cubic nonlinear Schrödinger (NLS) equation under an external spatiotemporal forcing of the form f(x,t)=aexp[iK(t)x]. For the case of time-independent forcing, a stability criterion for these solitons, which is based on a collective coordinate theory, was recently conjectured. We show that the proposed criterion has a limited applicability and present a refined criterion which is generally applicable, as confirmed by direct simulations. This includes more general situations where K(t) is harmonic or biharmonic, with or without a damping term in the NLS equation. The refined criterion states that the soliton will be unstable if the “stability curve” p(v), where p(t) and v(t) are the normalized momentum and the velocity of the soliton, has a section with a negative slope. In the case of a constant K and zero damping, we use the collective coordinate solutions to compute a “phase portrait” of the soliton where its dynamics is represented by two-dimensional projections of its trajectories in the four-dimensional space of collective coordinates. We conjecture, and confirm by simulations, that the soliton is unstable if a section of the resulting closed curve on the portrait has a negative sense of rotation.
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…
10 CFR 140.85 - Criterion II-Substantial damages to persons offsite or property offsite.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 10 Energy 2 2010-01-01 2010-01-01 false Criterion II-Substantial damages to persons offsite or property offsite. 140.85 Section 140.85 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) FINANCIAL... practical to restore to use, (4) Financial loss resulting from protective actions appropriate to reduce...
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.
ERIC Educational Resources Information Center
Duval County School Board, Jacksonville, FL.
Several intermediate performance objectives and corresponding criterion measures are presented for each of five terminal objectives for a 12- to 18-week course designed to provide students in grades 8 or 9 with opportunities to explore a broad range of clothing management, production, and service occupations. The course was designed to provide…
ERIC Educational Resources Information Center
Pizzo, Matthew J.; Kirkpatrick, Kimberly; Blundell, Pamela J.
2009-01-01
The differential reinforcement of low rate (DRL) schedule is commonly used to assess impulsivity, hyperactivity, and the cognitive effects of pharmacological treatments on performance. A DRL schedule requires subjects to wait a certain minimum amount of time between successive responses to receive reinforcement. The DRL criterion value, which…
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…
Statistical Techniques for Criterion-Referenced Tests. Final Report. October, 1976-October, 1977.
ERIC Educational Resources Information Center
Wilcox, Rand R.
Three statistical problems related to criterion-referenced testing are investigated: estimation of the likelihood of a false-positive or false-negative decision with a mastery test, estimation of true scores in the Compound Binomial Error Model, and comparison of the examinees to a control. Two methods for estimating the likelihood of…
Confidence Intervals for the Proportion of Mastery in Criterion-Referenced Measurement.
ERIC Educational Resources Information Center
Feldt, Leonard S.
1996-01-01
A relatively simple method is developed to obtain confidence intervals for a student's proportion of domain mastery in criterion-referenced or mastery measurement situations. The method uses the binomial distribution as a model for the student's scores under hypothetically repeated assessments, and it makes use of widely available "F"…
Evaluation of Weighted Scale Reliability and Criterion Validity: A Latent Variable Modeling Approach
ERIC Educational Resources Information Center
Raykov, Tenko
2007-01-01
A method is outlined for evaluating the reliability and criterion validity of weighted scales based on sets of unidimensional measures. The approach is developed within the framework of latent variable modeling methodology and is useful for point and interval estimation of these measurement quality coefficients in counseling and education…
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…
A Latent Trait Look at Pretest-Posttest Validation of Criterion-referenced Test Items.
ERIC Educational Resources Information Center
van der Linden, Wim J.
1981-01-01
Using criterion-referenced test item data collected in an empirical study, differences in item selection between Cox and Vargas' pretest-posttest validity index and a latent trait approach (evaluation of the item information function for the mastery score) are analyzed. (Author/GK)
An Item Response Model for Nominal Data Based on the Rising Selection Ratios Criterion
ERIC Educational Resources Information Center
Revuelta, Javier
2005-01-01
Complete response vectors of all answer options in multiple-choice items can be used to estimate ability. The rising selection ratios criterion is necessary for scoring individuals because it implies that estimated ability always increases when the correct alternative is selected. This paper introduces the generalized DLT model, which assumes…
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.
A novel criterion for evaluating the beam quality of high energy laser
NASA Astrophysics Data System (ADS)
Han, Kai; Sun, Quan; Xu, Xiaojun
2016-10-01
In this paper, a novel criterion for evaluating the beam quality of high energy laser is proposed, which is called "power outside the large bucket", POLB for short. The novel criterion does not demonstrate the divergence of the beam but focuses on the high spatial frequency wavefront aberration of the beam. The POLB values of the laser beams with various aberrations are calculated. It shows that the more high spatial frequency components in the aberration the larger POLB value is. Moreover, it is theoretically analyzed that the laser beams with various aberrations are corrected by ideal adaptive optics (AO) systems with different deformation mirror (DM) actuator numbers. It is shown that the residual error of the corrected wavefront aberration with many high spatial frequency components is quite large. Finally, the dependence of the residual wavefront error on the POLB value is investigated. Only if the POLB is smaller than 3.8/3.4/2.5/1.7 the residual error of the wavefront may be smaller than λ/10, which is corrected by an ideal AO system with 127/61/37/19 actuators. It is necessary to employ a complicated AO system for improving the laser beam of which the POLB value is large. The novel evaluating criterion POLB is able to demonstrate the amount of high spatial frequency aberration and the residual wavefront error corrected by AO system. It is an accessible and useful criterion for evaluating the beam quality of high energy lasers.
ERIC Educational Resources Information Center
Chen, Jean
In a 1973 Smithsonian behavioral science project, observational methods were used to record school group behaviors during docent guided tours in the National Museum of History and Technology. The purpose of this exploratory study was to reveal the natural museum habitat and criterion behaviors of visiting fourth through sixth graders. Children's…
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…
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…
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…
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…
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...
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, 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...
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, 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...
The Assessment of Self Concepts of Educational Achievement by a Criterion Referenced Approach.
ERIC Educational Resources Information Center
Norwich, Brahm
Self-concept ideas can be reformulated and integrated into an objectives oriented model of school learning. Bloom's model (1976) involving mastery learning already incorporates self-concept elements, but needs to be developed theoretically to include norm-referenced as well as criterion-referenced approaches to assessing self-concepts. This…
A Criterion-Related Validity Study of the OASIS-2 Interest Schedule.
ERIC Educational Resources Information Center
Levinson, Edward M.; And Others
1994-01-01
Describes correlational analyses between Self-Directed Search (SDS) and the second edition of the Occupational Aptitude Survey and Interest Schedule (OASIS-2). Scales generally correlate significantly at an acceptable level for establishing criterion-related validity. Implications for practitioners using the OASIS-2 are discussed. Includes 26…
Criterion-Related Validity of Curriculum-Based Measures in Writing for Secondary School Students.
ERIC Educational Resources Information Center
Espin, Christine A.; Scierka, Barbara J.; Skare, Stacey; Halverson, Nola
1999-01-01
Examines criterion-related validity of curriculum-based measures in written expression for secondary students. Finds a combination of measures was better than any single measure for predicting students' general performance in written expression; and 3 measures added to the prediction of students' general writing proficiency (number of characters…
ERIC Educational Resources Information Center
Dobbins, Ian G.; Kroll, Neal E. A.
2005-01-01
Superior detection and rejection of 1 versus another class of items during recognition is called the mirror effect. Some mirror effects may involve strategic criterion adjustments based on item distinctiveness and its relation to memorability. Three experiments demonstrated mirror effects for known versus unknown scenes and 1 suggested a similar…
Criterion-Referenced Test (CRT) Items for Air Conditioning, Heating and Refrigeration.
ERIC Educational Resources Information Center
Davis, Diane, Ed.
These criterion-referenced test (CRT) items for air conditioning, heating, and refrigeration are keyed to the Missouri Air Conditioning, Heating, and Refrigeration Competency Profile. The items are designed to work with both the Vocational Instructional Management System and Vocational Administrative Management System. For word processing and…
ERIC Educational Resources Information Center
Duval County School Board, Jacksonville, FL.
Several intermediate performance objectives and corresponding criterion measures are listed for each of seven terminal objectives for a 6- to 9-week orientation to home economics occupations course for seventh grade students. The titles of the seven terminal objectives are Overview, Human Care Cluster, Food and Nutrition, Home Service Cluster,…
Reviewing Employee Turnover: Focusing on Proximal Withdrawal States and an Expanded Criterion
ERIC Educational Resources Information Center
Hom, Peter W.; Mitchell, Terence R.; Lee, Thomas W.; Griffeth, Rodger W.
2012-01-01
We reconceptualize employee turnover to promote researchers' understanding and prediction of why employees quit or stay in employing institutions. A literature review identifies shortcomings with prevailing turnover dimensions. In response, we expand the conceptual domain of the turnover criterion to include multiple types of turnover (notably,…
16 CFR 1631.34 - Small carpets and rugs not meeting acceptance criterion.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 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 any small carpet or rug as defined in the Standard for the Surface Flammability of Small Carpets and...
16 CFR 1631.34 - Small carpets and rugs not meeting acceptance criterion.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 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 any small carpet or rug as defined in the Standard for the Surface Flammability of Small Carpets and...
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
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.…
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,…
Criterion-Referenced Assessment for Language Organization: An Example of Evidence-Based Practice
ERIC Educational Resources Information Center
Klecan-Aker, Joan S.; Colson, Karen
2009-01-01
Reliable criterion-referenced assessments are critical as one of the first steps in evidence-based practice. These assessments must also be valid. One of the most important skills to measure in school-age children with language disabilities is the ability to organize language in the form of narratives. The purpose of this paper is to describe a…
D.P.I. Primary Reading Criterion-Referenced Screening Test, Levels 1, 2, 3.
ERIC Educational Resources Information Center
Brown Education Center, Louisville, KY.
The Diagnostic Prescriptive Individualized (D.P.I.) Primary Reading Criterion-Referenced Screening Test Levels 1, 2 and 3 are diagnostic tests geared toward aiding the teacher of grade 1 and 2 children in identifying the academic strengths, weaknesses, and needs of each student. These tests are concerned with the overall screening of skills of…
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…
ERIC Educational Resources Information Center
Distefano, M. K., Jr.; And Others
1983-01-01
Demonstrated the use of quantitative content validity procedures in the development of a job-related behavioral rating scale criterion for entry-level psychiatric aides. Found that 78 of 83 items were significantly job-relevant using the computation procedures of both Lawshe and Aiken. (JAC)
ERIC Educational Resources Information Center
Rolider, Ahmos; Van Houten, Ron
1986-01-01
Two components of a gradually faded awakening procedure for treating bedwetting were tested with six children aged 4-11. Thorough awakening was more effective than partial awakening. A second experiment on advancing awakening time produced similar results between a stringent 6 consecutive dry night criterion and a more lenient 6 dry night…
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;…
An Extension of the Beale-Kato-Majda Criterion for the Euler Equations
NASA Astrophysics Data System (ADS)
Planchon, Fabrice
The Beale-Kato-Majda criterion asserts that smooth solutions to the Euler equations remain bounded past T as long as is finite, ohgr; being the vorticity. We show how to replace this by a weaker statement, on , where Δj is a frequency localization around .
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)
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
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)
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…
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…
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.
Vrieze, Scott I.
2012-01-01
This article reviews the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC) in model selection and the appraisal of psychological theory. The focus is on latent variable models given their growing use in theory testing and construction. We discuss theoretical statistical results in regression and illustrate more important issues with novel simulations involving latent variable models including factor analysis, latent profile analysis, and factor mixture models. Asymptotically, the BIC is consistent, in that it will select the true model if, among other assumptions, the true model is among the candidate models considered. The AIC is not consistent under these circumstances. When the true model is not in the candidate model set the AIC is effcient, in that it will asymptotically choose whichever model minimizes the mean squared error of prediction/estimation. The BIC is not effcient under these circumstances. Unlike the BIC, the AIC also has a minimax property, in that it can minimize the maximum possible risk in finite sample sizes. In sum, the AIC and BIC have quite different properties that require different assumptions, and applied researchers and methodologists alike will benefit from improved understanding of the asymptotic and finite-sample behavior of these criteria. The ultimate decision to use AIC or BIC depends on many factors, including: the loss function employed, the study's methodological design, the substantive research question, and the notion of a true model and its applicability to the study at hand. PMID:22309957
Vrieze, Scott I
2012-06-01
This article reviews the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) in model selection and the appraisal of psychological theory. The focus is on latent variable models, given their growing use in theory testing and construction. Theoretical statistical results in regression are discussed, and more important issues are illustrated with novel simulations involving latent variable models including factor analysis, latent profile analysis, and factor mixture models. Asymptotically, the BIC is consistent, in that it will select the true model if, among other assumptions, the true model is among the candidate models considered. The AIC is not consistent under these circumstances. When the true model is not in the candidate model set the AIC is efficient, in that it will asymptotically choose whichever model minimizes the mean squared error of prediction/estimation. The BIC is not efficient under these circumstances. Unlike the BIC, the AIC also has a minimax property, in that it can minimize the maximum possible risk in finite sample sizes. In sum, the AIC and BIC have quite different properties that require different assumptions, and applied researchers and methodologists alike will benefit from improved understanding of the asymptotic and finite-sample behavior of these criteria. The ultimate decision to use the AIC or BIC depends on many factors, including the loss function employed, the study's methodological design, the substantive research question, and the notion of a true model and its applicability to the study at hand.
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...
Romanowich, Paul; Lamb, R J
2014-08-01
Incentives have been successfully used to reduce smoking in hard-to-treat (HTT) smokers by progressively reinforcing lower levels of breath carbon monoxide (CO). When compared with schedules only providing incentives for smoking abstinence, using a progressive (percentile) criterion facilitates longer periods of smoking abstinence. However, participants receiving incentives for lower breath CO levels on percentile schedules typically earn more for their first abstinent breath CO sample relative to participants receiving incentives only for smoking abstinence. Many studies show that larger incentive magnitude increases abstinence rates. The present study tested the effects of different incentive schedules on rates of abstinence maintenance while holding the initial incentive magnitude constant for 93 HTT smokers to eliminate initial abstinence incentive magnitude as a potential confound. Smokers were randomized to percentile, fixed criterion, or random incentive schedules. The incentive magnitude for the first abstinent breath CO sample (<3 ppm) was $5 for percentile and fixed criterion incentive participants, and then increased by $0.50 for each consecutive abstinent breath CO sample. All groups had similar patterns of meeting the abstinence criterion for at least 1 visit. However, once this abstinence criterion was met, abstinence was more likely to be maintained by fixed criterion incentive participants. Unlike previous studies comparing percentile and fixed criterion schedules, percentile incentive schedules were not associated with longer periods of abstinence relative to fixed criterion incentive schedules. Further studies that manipulate initial incentive magnitude are needed to test whether the difference between the current and previous studies was due to initial incentive magnitude.
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, 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...
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, 2014 CFR
2014-01-01
... 10 Energy 4 2014-01-01 2014-01-01 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…
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.
NASA Astrophysics Data System (ADS)
Ye, Zhuan
2016-12-01
This paper is devoted to the investigation of the regularity criterion to the two-dimensional (2D) Euler-Boussinesq equations with supercritical dissipation. By making use of the Littlewood-Paley technique, we provide an improved regularity criterion involving the temperature at the scaling invariant level, which improves the previous results.
Criterion distances and environmental correlates of active commuting to school in children
2011-01-01
Background Active commuting to school can contribute to daily physical activity levels in children. Insight into the determinants of active commuting is needed, to promote such behavior in children living within a feasible commuting distance from school. This study determined feasible distances for walking and cycling to school (criterion distances) in 11- to 12-year-old Belgian children. For children living within these criterion distances from school, the correlation between parental perceptions of the environment, the number of motorized vehicles per family and the commuting mode (active/passive) to school was investigated. Methods Parents (n = 696) were contacted through 44 randomly selected classes of the final year (sixth grade) in elementary schools in East- and West-Flanders. Parental environmental perceptions were obtained using the parent version of Neighborhood Environment Walkability Scale for Youth (NEWS-Y). Information about active commuting to school was obtained using a self-reported questionnaire for parents. Distances from the children's home to school were objectively measured with Routenet online route planner. Criterion distances were set at the distance in which at least 85% of the active commuters lived. After the determination of these criterion distances, multilevel analyses were conducted to determine correlates of active commuting to school within these distances. Results Almost sixty percent (59.3%) of the total sample commuted actively to school. Criterion distances were set at 1.5 kilometers for walking and 3.0 kilometers for cycling. In the range of 2.01 - 2.50 kilometers household distance from school, the number of passive commuters exceeded the number of active commuters. For children who were living less than 3.0 kilometers away from school, only perceived accessibility by the parents was positively associated with active commuting to school. Within the group of active commuters, a longer distance to school was associated with
NASA Astrophysics Data System (ADS)
Battaglia, Eleonora; Bonollo, Franco; Ferro, Paolo
2017-03-01
Defects, particularly porosity and oxides, in high-pressure die casting can seriously compromise the in-service behavior and durability of products subjected to static or cyclic loadings. In this study, the influence of dimension, orientation, and position of casting defects on the mechanical properties of an AlSi12(b) (EN-AC 44100) aluminum alloy commercial component has been studied. A finite element model has been carried out in order to calculate the stress distribution induced by service loads and identify the crack initiation zones. Castings were qualitatively classified on the basis of porosities distribution detected by X-ray technique and oxides observed on fracture surfaces of specimens coming from fatigue and tensile tests. A damage criterion has been formulated which considers the influence of defects position and orientation on the mechanical strength of the components. Using the proposed damage criterion, it was possible to describe the mechanical behavior of the castings with good accuracy.
Application of the Electrical Network Frequency (ENF) Criterion. A case of a digital recording.
Kajstura, Mateusz; Trawinska, Agata; Hebenstreit, Jacek
2005-12-20
One of the new methods of investigating the authenticity of evidential digital audio recordings uses the Electrical Network Frequency (ENF) Criterion. It is based on analysing the signal corresponding to the fundamental frequency of the current in the electrical network, which is present in a recording and comparing it with appropriate, reliable reference. Studies carried out at the Institute of Forensic Research in Cracow were aimed at validating this method, that is, assessing its usefulness in forensic examinations of evidential digital recordings in Poland. These studies enabled us to develop and implement a procedure for using the ENF Criterion method to assess the integrity of digital recordings and to establish when these recordings were made.
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.
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.
An Optimal Partial Differential Equations-based Stopping Criterion for Medical Image Denoising.
Khanian, Maryam; Feizi, Awat; Davari, Ali
2014-01-01
Improving the quality of medical images at pre- and post-surgery operations are necessary for beginning and speeding up the recovery process. Partial differential equations-based models have become a powerful and well-known tool in different areas of image processing such as denoising, multiscale image analysis, edge detection and other fields of image processing and computer vision. In this paper, an algorithm for medical image denoising using anisotropic diffusion filter with a convenient stopping criterion is presented. In this regard, the current paper introduces two strategies: utilizing the efficient explicit method due to its advantages with presenting impressive software technique to effectively solve the anisotropic diffusion filter which is mathematically unstable, proposing an automatic stopping criterion, that takes into consideration just input image, as opposed to other stopping criteria, besides the quality of denoised image, easiness and time. Various medical images are examined to confirm the claim.
Carnevale, Federico; de Lafuente, Victor; Romo, Ranulfo; Barak, Omri; Parga, Néstor
2015-05-20
Under uncertainty, the brain uses previous knowledge to transform sensory inputs into the percepts on which decisions are based. When the uncertainty lies in the timing of sensory evidence, however, the mechanism underlying the use of previously acquired temporal information remains unknown. We study this issue in monkeys performing a detection task with variable stimulation times. We use the neural correlates of false alarms to infer the subject's response criterion and find that it modulates over the course of a trial. Analysis of premotor cortex activity shows that this modulation is represented by the dynamics of population responses. A trained recurrent network model reproduces the experimental findings and demonstrates a neural mechanism to benefit from temporal expectations in perceptual detection. Previous knowledge about the probability of stimulation over time can be intrinsically encoded in the neural population dynamics, allowing a flexible control of the response criterion over time.
External Single-Set Components Analysis Of Multiple Criterion/Multiple Predictor Variables.
Fornell, C
1979-07-01
Although much progress has been made in clarifying the properties of canonical correlation analysis in order to enhance its applicability, there are several remaining problems. Canonical variates do not always represent the observed variables even though the canonical correlation is high. In addition, canonical solutions are often difficult to interpret. This paper presents a method designed to deal with these two problems. Instead of maximizing the correlation between unobserved variates, the sum of squared inter-set loadings is maximized. Contrary to the canonical correlation solution, this method ensures that the shared variance between predictor variates and criterion variables is maximal. Instead of extracting variates from both criterion and predictor variables, only one set of components (from the predictor variables) is constructed. Without loss of common variance, an orthogonal rotation is applied to the resulting loadings in order to simplify structure.
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.
Corrections to the Eckhaus' stability criterion for one-dimensional stationary structures
NASA Astrophysics Data System (ADS)
Malomed, B. A.; Staroselsky, I. E.; Konstantinov, A. B.
1989-01-01
Two amendments to the well-known Eckhaus' stability criterion for small-amplitude non-linear structures generated by weak instability of a spatially uniform state of a non-equilibrium one-dimensional system against small perturbations with finite wavelengths are obtained. Firstly, we evaluate small corrections to the main Eckhaus' term which, on the contrary so that term, do not have a universal form. Comparison of those non-universal corrections with experimental or numerical results gives a possibility to select a more relevant form of an effective nonlinear evolution equation. In particular, the comparison with such results for convective rolls and Taylor vortices gives arguments in favor of the Swift-Hohenberg equation. Secondly, we derive an analog of the Eckhaus criterion for systems degenerate in the sense that in an expansion of their non-linear parts in powers of dynamical variables, the second and third degree terms are absent.
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)
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.
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 Statistics-Based Cracking Criterion of Resin-Bonded Silica Sand for Casting Process Simulation
NASA Astrophysics Data System (ADS)
Wang, Huimin; Lu, Yan; Ripplinger, Keith; Detwiler, Duane; Luo, Alan A.
2017-02-01
Cracking of sand molds/cores can result in many casting defects such as veining. A robust cracking criterion is needed in casting process simulation for predicting/controlling such defects. A cracking probability map, relating to fracture stress and effective volume, was proposed for resin-bonded silica sand based on Weibull statistics. Three-point bending test results of sand samples were used to generate the cracking map and set up a safety line for cracking criterion. Tensile test results confirmed the accuracy of the safety line for cracking prediction. A laboratory casting experiment was designed and carried out to predict cracking of a cup mold during aluminum casting. The stress-strain behavior and the effective volume of the cup molds were calculated using a finite element analysis code ProCAST®. Furthermore, an energy dispersive spectroscopy fractographic examination of the sand samples confirmed the binder cracking in resin-bonded silica sand.
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.
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%.
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.
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.
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.
Experimental evaluation of the tensor polynomial criterion for designing composite structures
NASA Technical Reports Server (NTRS)
Tennyson, R. C.
1977-01-01
A comprehensive experimental and analytical evaluation of the tensor polynomial failure criterion was undertaken to determine its capability for predicting the ultimate strength of a composite limina subject to a plane stress state. Results are presented demonstrating that a quadratic formulation is too conservative and a cubic representation is required. Strength comparisons with test data derived from glass/epoxy and graphite/epoxy tubular specimens are also provided to validate the cubic strength criterion. Environmental effects including ambient temperature, exposure to vacuum, length of post-cure time, and rate of cool down were also investigated. Behavior changes associated with polymer (epoxy) matrix composites were determined in terms of variations in stiffness and tensile strength.
Accuracy of visual estimates of joint angle and angular velocity using criterion movements.
Morrison, Craig S; Knudson, Duane; Clayburn, Colby; Haywood, Philip
2005-06-01
A descriptive study to document undergraduate physical education majors' (22.8 +/- 2.4 yr. old) estimates of sagittal plane elbow angle and angular velocity of elbow flexion visually was performed. 42 subjects rated videotape replays of 30 movements organized into three speeds of movement and two criterion elbow angles. Video images of the movements were analyzed with Peak Motus to measure actual values of elbow angles and peak angular velocity. Of the subjects 85.7% had speed ratings significantly correlated with true peak elbow angular velocity in all three angular velocity conditions. Few (16.7%) subjects' ratings of elbow angle correlated significantly with actual angles. Analysis of the subjects with good ratings showed the accuracy of visual ratings was significantly related to speed, with decreasing accuracy for slower speeds of movement. The use of criterion movements did not improve the small percentage of novice observers who could accurately estimate body angles during movement.
Using the ENF Criterion for Determining the Time of Recording of Short Digital Audio Recordings
NASA Astrophysics Data System (ADS)
Huijbregtse, Maarten; Geradts, Zeno
The Electric Network Frequency (ENF) Criterion is a recently developed forensic technique for determining the time of recording of digital audio recordings, by matching the ENF pattern from a questioned recording with an ENF pattern database. In this paper we discuss its inherent limitations in the case of short - i.e., less than 10 minutes in duration - digital audio recordings. We also present a matching procedure based on the correlation coefficient, as a more robust alternative to squared error matching.
The quartic piecewise-linear criterion for the multiaxial yield behavior of human trabecular bone.
Sanyal, Arnav; Scheffelin, Joanna; Keaveny, Tony M
2015-01-01
Prior multiaxial strength studies on trabecular bone have either not addressed large variations in bone volume fraction and microarchitecture, or have not addressed the full range of multiaxial stress states. Addressing these limitations, we utilized micro-computed tomography (lCT) based nonlinear finite element analysis to investigate the complete 3D multiaxial failure behavior of ten specimens (5mm cube) of human trabecular bone, taken from three anatomic sites and spanning a wide range of bone volume fraction (0.09–0.36),mechanical anisotropy (range of E3/E1¼3.0–12.0), and microarchitecture. We found that most of the observed variation in multiaxial strength behavior could be accounted for by normalizing the multiaxial strength by specimen-specific values of uniaxial strength (tension,compression in the longitudinal and transverse directions). Scatter between specimens was reduced further when the normalized multiaxial strength was described in strain space.The resulting multiaxial failure envelope in this normalized-strain space had a rectangular boxlike shape for normal–normal loading and either a rhomboidal box like shape or a triangular shape for normal-shear loading, depending on the loading direction. The finite element data were well described by a single quartic yield criterion in the 6D normalized strain space combined with a piecewise linear yield criterion in two planes for normalshear loading (mean error SD: 4.660.8% for the finite element data versus the criterion).This multiaxial yield criterion in normalized-strain space can be used to describe the complete 3D multiaxial failure behavior of human trabecular bone across a wide range of bone volume fraction, mechanical anisotropy, and microarchitecture.
Method of characteristics for the 3D perfect plasticity problem with the von Mises yield criterion
NASA Astrophysics Data System (ADS)
Verveyko, N. D.; Kuptsov, A. V.
2009-04-01
We present a linearized system of partial differential equations for the three-dimensional perfect plasticity problem with the von Mises yield criterion. We construct the characteristics of the three-dimensional problem, obtain differential relations along the characteristic planes, and devise a consistent stable finite-difference scheme. The use of conditions on the stress discontinuity surfaces permits simultaneously solving the Cauchy, Goursat, and mixed problems.
Development of a Strain Rate Dependent Long Bone Injury Criterion for Use with the ATB Model.
1982-01-12
of safety; or some other criterion such as maximum strain or strain energy . At present the ultimate strength, reduced by a factor of safety, is thought...NOT STORED IN THE ARRAY 00000410 - OR WRITTEN TO THE DISK OR PRINTER. 00000420 00000430 NP = THE NUMBER O? RECORDS THAT OCCUR BETWEEN PAGE HEADERS...00000220 00000230 POTATE "OTHER CONSTRAINT FORCE" LOCATION TO X-AXIAL COORDINATES 00000240 WITH THE ORIGIN AT THE. PROXIMAL JOINT 00000250 00000260 DO 3 I
1982-12-01
multiattribute value functions. Operations Research, 1979, 27, 810-822. Fishburn, P. Utility theory for decision making. New York: Wiley, 1970...Psychology, 1980, 21, 66-82. v. Winterfeldt, D. and Fischer, G.W. Multiattribute utility theory : models and assessment procedres. In D. Wendt and...plicative value functions: A criterion _____________ validation of multiattribute utility 6. 7EPPORMING ONG. RgPeR? NUgMBER techn iclues 82-1 AijWOR*JS
An Anisotropic Partial Regularity Criterion for the Navier-Stokes Equations
NASA Astrophysics Data System (ADS)
Kukavica, Igor; Rusin, Walter; Ziane, Mohammed
2017-03-01
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).
An excitation spectrum criterion for the vibration-induced fatigue of small bore pipes
NASA Astrophysics Data System (ADS)
Moussou, P.
2003-09-01
The purpose of the study is to determine an easy-to-use criterion to evaluate the risk of vibration-induced fatigue of small bore pipes. The failure mechanism considered is the resonant amplification of a stationary broadband excitation by the main pipe, leading to bending stresses above the fatigue limit of the steel. Based on the Euler beam theory, a simple model is built up for the natural mode shapes of the small bore pipe close to its root. It is shown that the velocity spectrum at the root of the small bore pipe is equal to the r.m.s. value of the bending stress multiplied by a function of the natural frequency, the damping coefficient, the speed of elastic waves in the steel, Young's modulus and a nondimensional factor weakly depending on the geometry of the small bore pipe. A maximum velocity spectrum can then be deduced, assuming that a small bore pipe vibrates mainly on its natural mode shapes. The maximum excitation spectrum is defined for each frequency f as the one which would generate a maximum bending stress equal to the endurance limit of the steel, would the small bore pipe have a natural frequency equal to f. Using envelope values of the nondimensional factor, the stress intensification factor, the peak factor and the endurance limit of the steel, one obtains the following maximum velocity spectrum for the stainless steel: v<6mm/s/sqrt(f), and the following maximum velocity spectrum for the ferritic steel: v<2.7mm/s/sqrt(f). The velocity spectrum criterion appears less penalizing than the 12mm/s criterion and more conservative than the strict enforcement of the ANSI-OM3 standard. Comparisons with former plant studies show that the velocity spectrum criterion leads to the correct fatigue diagnosis.
2007-11-02
BAROREFLEX SENSITIVITY ESTIMATION BY THE TRANSFER FUNCTION METHOD REVISED: EFFECT OF CHANGING THE COHERENCE CRITERION G.D. Pinna1, R. Maestri1, G...In this study we appraised three new criteria for the computation of baroreflex sensitivity (BRS) using the transfer function magnitude (TFM) method... Baroreflex sensitivity , spectral analysis, transfer function I. INTRODUCTION Among the different spectral methods proposed so far for the estimation of
On the Gap-opening Criterion of Migrating Planets in Protoplanetary Disks
NASA Astrophysics Data System (ADS)
Malik, M.; Meru, F.; Mayer, L.; Meyer, M.
2015-03-01
We perform two-dimensional hydrodynamical simulations to quantitatively explore the torque balance criterion for gap-opening (as formulated by Crida et al.) in a variety of disks when considering a migrating planet. We find that even when the criterion is satisfied, there are instances when planets still do not open gaps. We stress that gap-opening is not only dependent on whether a planet has the ability to open a gap, but whether it can do so quickly enough. This can be expressed as an additional condition on the gap-opening timescale, {{t}gap}, versus the crossing time, {{t}cross}, i.e., the time it takes the planet to cross the region which it is carving out. While this point has been briefly made in the previous literature, our results quantify it for a range of protoplanetary disk properties and planetary masses, demonstrating how crucial it is for gap-opening. This additional condition has important implications for the survival of planets formed by core accretion in low mass disks as well as giant planets or brown dwarfs formed by gravitational instability in massive disks. It is particularly important for planets with intermediate masses susceptible to Type III-like migration. For some observed transition disks or disks with gaps, we expect that estimates on the potential planet masses based on the torque balance gap-opening criterion alone may not be sufficient. With consideration of this additional timescale criterion theoretical studies may find a reduced planet survivability or that planets may migrate further inwards before opening a gap.
Ignition criterion and safety prediction of explosives under low velocity impact
NASA Astrophysics Data System (ADS)
Ma, Danzhu; Chen, Pengwan; Zhou, Qiang; Dai, Kaida
2013-09-01
Due to the complexity of impact-induced reaction, it is difficult to predict and evaluate the ignition and safety of explosives under low velocity impact. Plastic deformation is very important to explosive ignition under impact loading. At low strain rates, plastic deformation can be treated as an isothermal process. The deformation under high-strain-rate is usually seen as an adiabatic process, and the deformation work is transformed into heat with the attendant temperature increase of the explosive. In this paper, we proposed an ignition criterion in terms of effective plastic work and specific plastic power to predict the ignition of explosives under low velocity impact. The plastic work begins to accumulate, when the specific plastic power (i.e., the plastic strain rate) in a local region meets a threshold value; and when the plastic work is sufficient enough, the ignition occurs. The criterion parameters are determined by numerical simulation using LS-DYNA. Numerical simulation is compared with experimental data in order to calibrate the numerical model. The threshold values of this ignition criterion for different configurations are determined. In order to evaluate the validity of the criterion, the predictions of the ignition time, ignition zone, threshold velocities in Steven test with different PBX size designs and various projectiles, as well as the ignition threshold conditions in a modified drop weight test, Susan test, and Spigot test, are carried out. The predicted results show a good agreement with experimental results, and the errors of the ignition threshold are less than 15% for all the experimental configurations.
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.
2011-11-01
closed-form approximate yield criteria were obtained for both spherical and cylindrical voids. Numerical studies have been conducted to verify and...developed criterion for plastic anisotropic med- ia displaying strength–differential effects is assessed through com- parison with numerical results...element X, composed of a homogeneous rigid-plastic matrix and a traction-free void. The matrix material is described by a convex yield function u(r) in
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…
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.
Applications of ENF criterion in forensic audio, video, computer and telecommunication analysis.
Grigoras, Catalin
2007-04-11
This article reports on the electric network frequency criterion as a means of assessing the integrity of digital audio/video evidence and forensic IT and telecommunication analysis. A brief description is given to different ENF types and phenomena that determine ENF variations. In most situations, to reach a non-authenticity opinion, the visual inspection of spectrograms and comparison with an ENF database are enough. A more detailed investigation, in the time domain, requires short time windows measurements and analyses. The stability of the ENF over geographical distances has been established by comparison of synchronized recordings made at different locations on the same network. Real cases are presented, in which the ENF criterion was used to investigate audio and video files created with secret surveillance systems, a digitized audio/video recording and a TV broadcasted reportage. By applying the ENF Criterion in forensic audio/video analysis, one can determine whether and where a digital recording has been edited, establish whether it was made at the time claimed, and identify the time and date of the registering operation.
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 local criterion for cleavage fracture of a nuclear pressure vessel steel
Bermin, F.M.
1983-11-01
Experiments were performed on three heats of A508 class 3 steel in order to determine the mechanical conditions for cleavage fracture. These tests were carried out on various geometries including 4-point bend specimens and axisymmetric notched tensile bars with different notch radii which have been modelized using the finite element method. In one heat, the temperature range investigated was from 77 K to 233 K. It is shown that the cleavage resistance is increased by tensile straining. Moreover, the probability of fracture obeys the Weibull statistical distribution. All the results can be accounted for in terms of a local criterion based on Weibull theory and which takes into account the effect of plastic strain. In this criterion, the parameters which were experimentally determined are found to be temperature independent over the range 77 K to 170 K. The applicability of the approach proposed for cleavage fracture at the crack tip is also examined. It is shown that the experimental results published in the literature giving the variation of fracture toughness with temperature can be explained by the proposed criterion which predicts reasonably well both the scatter in the experimental results and the K /SUB IC/ temperature dependence.
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.
Reduction criterion of separability and limits for a class of distillation protocols
NASA Astrophysics Data System (ADS)
Horodecki, Michał; Horodecki, Paweł
1999-06-01
We analyze the problem of distillation of entanglement of mixed states in higher-dimensional compound systems. Employing the positive maps method [M. Horodecki et al., Phys. Lett. A 223, 1 (1996)] we introduce and analyze a criterion of separability that relates the structures of the total density matrix and its reductions. We show that any state violating the criterion can be distilled by suitable generalization of the two-qubit protocol that distills any inseparable two-qubit state. In particular, this means that any state ϱ of two N-level systems with <ψ+\\|ϱ\\|ψ+>>1/N can be distilled (ψ+ is the singlet state generalized to higher dimension). The criterion also singles out all the states that can be distilled by a class of protocols. The proof involves construction of the family of states that are invariant under transformation ϱ-->U⊗U*ϱU†⊗U*†, where U is a unitary transformation and the asterisk denotes complex conjugation. The states are related to the depolarizing channel generalized to the nonbinary case.
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.
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.
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.
NASA Astrophysics Data System (ADS)
Zhu, Qi-Zhi
2017-02-01
A proper criterion describing when material fails is essential for deep understanding and constitutive modeling of rock damage and failure by microcracking. Physically, such a criterion should be the global effect of local mechanical response and microstructure evolution inside the material. This paper aims at deriving a new mechanisms-based failure criterion for brittle rocks, based on micromechanical unilateral damage-friction coupling analyses rather than on the basic results from the classical linear elastic fracture mechanics. The failure functions respectively describing three failure modes (purely tensile mode, tensile-shear mode as well as compressive-shear mode) are achieved in a unified upscaling framework and illustrated in the Mohr plane and also in the plane of principal stresses. The strength envelope is proved to be continuous and smooth with a compressive to tensile strength ratio dependent on material properties. Comparisons with experimental data are finally carried out. By this work, we also provide a theoretical evidence on the hybrid failure and the smooth transition from tensile failure to compressive-shear failure.
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.
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.
Experiments and modeling of ballistic penetration using an energy failure criterion
NASA Astrophysics Data System (ADS)
Dolinski, M.; Rittel, D.
2015-09-01
One of the most intricate problems in terminal ballistics is the physics underlying penetration and perforation. Several penetration modes are well identified, such as petalling, plugging, spall failure and fragmentation (Sedgwick, 1968). In most cases, the final target failure will combine those modes. Some of the failure modes can be due to brittle material behavior, but penetration of ductile targets by blunt projectiles, involving plugging in particular, is caused by excessive localized plasticity, with emphasis on adiabatic shear banding (ASB). Among the theories regarding the onset of ASB, new evidence was recently brought by Rittel et al. (2006), according to whom shear bands initiate as a result of dynamic recrystallization (DRX), a local softening mechanism driven by the stored energy of cold work. As such, ASB formation results from microstructural transformations, rather than from thermal softening. In our previous work (Dolinski et al., 2010), a failure criterion based on plastic strain energy density was presented and applied to model four different classical examples of dynamic failure involving ASB formation. According to this criterion, a material point starts to fail when the total plastic strain energy density reaches a critical value. Thereafter, the strength of the element decreases gradually to zero to mimic the actual material mechanical behavior. The goal of this paper is to present a new combined experimental-numerical study of ballistic penetration and perforation, using the above-mentioned failure criterion. Careful experiments are carried out using a single combination of AISI 4340 FSP projectiles and 25[mm] thick RHA steel plates, while the impact velocity, and hence the imparted damage, are systematically varied. We show that our failure model, which includes only one adjustable parameter in this present work, can faithfully reproduce each of the experiments without any further adjustment. Moreover, it is shown that the most common
Experiments and modeling of ballistic penetration using an energy failure criterion
NASA Astrophysics Data System (ADS)
Dolinski, M.; Rittel, D.
2015-10-01
One of the most intricate problems in terminal ballistics is the physics underlying penetration and perforation. Several penetration modes are well identified, such as petalling, plugging, spall failure and fragmentation (Sedgwick, 1968). In most cases, the final target failure will combine those modes. Some of the failure modes can be due to brittle material behavior, but penetration of ductile targets by blunt projectiles, involving plugging in particular, is caused by excessive localized plasticity, with emphasis on adiabatic shear banding (ASB). Among the theories regarding the onset of ASB, new evidence was recently brought by Rittel et al. (2006), according to whom shear bands initiate as a result of dynamic recrystallization (DRX), a local softening mechanism driven by the stored energy of cold work. As such, ASB formation results from microstructural transformations, rather than from thermal softening. In our previous work (Dolinski et al., 2010), a failure criterion based on plastic strain energy density was presented and applied to model four different classical examples of dynamic failure involving ASB formation. According to this criterion, a material point starts to fail when the total plastic strain energy density reaches a critical value. Thereafter, the strength of the element decreases gradually to zero to mimic the actual material mechanical behavior. The goal of this paper is to present a new combined experimental-numerical study of ballistic penetration and perforation, using the above-mentioned failure criterion. Careful experiments are carried out using a single combination of AISI 4340 FSP projectiles and 25[mm] thick RHA steel plates, while the impact velocity, and hence the imparted damage, are systematically varied. We show that our failure model, which includes only one adjustable parameter in this present work, can faithfully reproduce each of the experiments without any further adjustment. Moreover, it is shown that the most common
A Simple Criterion to Estimate Performance of Pulse Jet Mixed Vessels
Pease, Leonard F.; Bamberger, Judith A.; Mahoney, Lenna A.; Yokuda, Satoru T.; Minette, Michael J.
2016-07-10
Pulse jet mixed process vessels comprise a key element of the U.S. Department of Energy’s strategy to process millions of gallons of legacy nuclear waste slurries. Slurry suctioned into a pulse jet mixer (PJM) tube at the end of one pulse is pneumatically driven from the PJM toward the bottom of the vessel at the beginning of the next pulse, forming a jet. The jet front traverses the distance from nozzle outlet to the bottom of the vessel and spreads out radially. Varying numbers of PJMs are typically arranged in a ring configuration within the vessel at a selected radius and operated concurrently. Centrally directed radial flows from neighboring jets collide to create a central upwell that elevates the solids in the center of the vessel when the PJM tubes expel their contents. An essential goal of PJM operation is to elevate solids to the liquid surface to minimize stratification. Solids stratification may adversely affect throughput of the waste processing plant. Unacceptably high slurry densities at the base of the vessel may plug the pipeline through which the slurry exits the vessel. Additionally, chemical reactions required for processing may not achieve complete conversion. To avoid these conditions, a means of predicting the elevation to which the solids rise in the central upwell that can be used during vessel design remains essential. In this paper we present a simple criterion to evaluate the extent of solids elevation achieved by a turbulent upwell jet. The criterion asserts that at any location in the central upwell the local velocity must be in excess of a cutoff velocity to remain turbulent. We find that local velocities in excess of 0.6 m/s are necessary for turbulent jet flow through both Newtonian and yield stress slurries. By coupling this criterion with the free jet velocity equation relating the local velocity to elevation in the central upwell, we estimate the elevation at which turbulence fails, and consequently the elevation at which the
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.
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.
NASA Astrophysics Data System (ADS)
Hou, Yanqing; Verhagen, Sandra; Wu, Jie
2016-12-01
Ambiguity Resolution (AR) is a key technique in GNSS precise positioning. In case of weak models (i.e., low precision of data), however, the success rate of AR may be low, which may consequently introduce large errors to the baseline solution in cases of wrong fixing. Partial Ambiguity Resolution (PAR) is therefore proposed such that the baseline precision can be improved by fixing only a subset of ambiguities with high success rate. This contribution proposes a new PAR strategy, allowing to select the subset such that the expected precision gain is maximized among a set of pre-selected subsets, while at the same time the failure rate is controlled. These pre-selected subsets are supposed to obtain the highest success rate among those with the same subset size. The strategy is called Two-step Success Rate Criterion (TSRC) as it will first try to fix a relatively large subset with the fixed failure rate ratio test (FFRT) to decide on acceptance or rejection. In case of rejection, a smaller subset will be fixed and validated by the ratio test so as to fulfill the overall failure rate criterion. It is shown how the method can be practically used, without introducing a large additional computation effort. And more importantly, how it can improve (or at least not deteriorate) the availability in terms of baseline precision comparing to classical Success Rate Criterion (SRC) PAR strategy, based on a simulation validation. In the simulation validation, significant improvements are obtained for single-GNSS on short baselines with dual-frequency observations. For dual-constellation GNSS, the improvement for single-frequency observations on short baselines is very significant, on average 68%. For the medium- to long baselines, with dual-constellation GNSS the average improvement is around 20-30%.
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)
Estimation of a Stopping Criterion for Geophysical Granular Flows Based on Numerical Experimentation
NASA Astrophysics Data System (ADS)
Yu, B.; Dalbey, K.; Bursik, M.; Patra, A.; Pitman, E. B.
2004-12-01
Inundation area may be the most important factor for mitigation of natural hazards related to avalanches, debris flows, landslides and pyroclastic flows. Run-out distance is the key parameter for inundation because the front deposits define the leading edge of inundation. To define the run-out distance, it is necessary to know when a flow stops. Numerical experiments are presented for determining a stopping criterion and exploring the suitability of a Savage-Hutter granular model for computing inundation areas of granular flows. The TITAN2D model was employed to run numerical experiments based on the Savage-Hutter theory. A potentially reasonable stopping criterion was found as a function of dimensionless average velocity, aspect ratio of pile, internal friction angle, bed friction angle and bed slope in the flow direction. Slumping piles on a horizontal surface and geophysical flows over complex topography were simulated. Several mountainous areas, including Colima volcano (MX), Casita (Nic.), Little Tahoma Peak (WA, USA) and the San Bernardino Mountains (CA, USA) were used to simulate geophysical flows. Volcanic block and ash flows, debris avalanches and debris flows occurred in these areas and caused varying degrees of damage. The areas have complex topography, including locally steep open slopes, sinuous channels, and combinations of these. With different topography and physical scaling, slumping piles and geophysical flows have a somewhat different dependence of dimensionless stopping velocity on power-law constants associated with aspect ratio of pile, internal friction angle, bed friction angle and bed slope in the flow direction. Visual comparison of the details of the inundation area obtained from the TITAN2D model with models that contain some form of viscous dissipation point out weaknesses in the model that are not evident by investigation of the stopping criterion alone.
Martin, Donald E.K.
2014-01-01
Abstract Spaced seeds have been recently shown to not only detect more alignments, but also to give a more accurate measure of phylogenetic distances, and to provide a lower misclassification rate when used with Support Vector Machines (SVMs). We confirm by independent experiments these two results, and propose in this article to use a coverage criterion to measure the seed efficiency in both cases in order to design better seed patterns. We show first how this coverage criterion can be directly measured by a full automaton-based approach. We then illustrate how this criterion performs when compared with two other criteria frequently used, namely the single-hit and multiple-hit criteria, through correlation coefficients with the correct classification/the true distance. At the end, for alignment-free distances, we propose an extension by adopting the coverage criterion, show how it performs, and indicate how it can be efficiently computed. PMID:25393923
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
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
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.
Criterion for the prevention of core fracture during extrusion of bimetal rods
Avitzur, B.; Wu, R.; Talbert, S.; Chou, Y.T.
1980-09-01
Based on the upper-bound theorem in limit analysis, a theoretical model for core fracture in bimetal rods during extrusion has been developed and a fracture criterion established. The variables affecting core fracture are: reduction in area (r%), die geometry, friction (m), relative size of the core and relative strength of the core. Within the wide range of possible combinations of these process variables, only a small range permits extrusion without fracture. With suitable modifications the present analysis can be extended to develop criteria for sleeve fracture during extrusion and for both core and sleeve fracture during drawing.
An alternative proof of Lie's linearization theorem using a new λ -symmetry criterion
NASA Astrophysics Data System (ADS)
Al-Dweik, Ahmad Y.; Mustafa, M. T.; Mara'Beh, Raed A.; Mahomed, F. M.
2015-09-01
An alternative proof of Lie's approach for the linearization of scalar second-order ordinary differential equations is derived by using the relationship between λ -symmetries and first integrals. This relation further leads to a new λ -symmetry linearization criterion for second-order ordinary differential equations which provides a new approach for constructing the linearization transformations with lower complexity. The effectiveness of the approach is illustrated by obtaining the local linearization transformations for the linearizable nonlinear ordinary differential equations of the form y″ +F1 (x, y)y‧ + F (x, y) = 0 . Examples of linearizable nonlinear ordinary differential equations which are quadratic or cubic in the first derivative are also presented.
Criterion for material selection in design of bulk piezoelectric energy harvesters.
Priya, Shashank
2010-12-01
Vibration energy harvesting has gained tremendous attention in the past decade and continues to grow rapidly. There are various transduction mechanisms for converting the vibration energy into electrical energy, out of which the piezoelectric mechanism has been shown to provide advantages at the micro-to-meso scale. In the past few years, several studies have tried to address the question of which piezoelectric composition is better for energy harvesting; however, discussion on this subject continues. The intent of this letter is to provide an answer for this question through a simple criterion which can be used in routine material evaluation.
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.
A Computational Study of Cavitation Model Validity Using a New Quantitative Criterion
NASA Astrophysics Data System (ADS)
Hagar Alm, El-Din; Zhang, Yu-Sheng; Medhat, Elkelawy
2012-06-01
The predictive capability of two different numerical cavitation models accounting for the onset and development of cavitation inside real-sized diesel nozzle holes is assessed on the basis of the referenced experimental data. The calculations performed indicate that for the same model assumptions, numerical implementation, discretization scheme, and turbulence grid resolution model, the predictions for differently applied physical cavitation submodels are phenomenologically distinct from each other. We present a comparison by applying a new criterion for the quantitative comparison between the results obtained from both cavitation models.
Unique criterion to estimate the performances of some laser diode range finders
NASA Astrophysics Data System (ADS)
Journet, Bernard A.; Bazin, Gaelle; Durieu, Cecile
2001-09-01
The purpose of this paper is to present a general method to estimate the intrinsic performances of some laser range finders based on flight time measurement. Classically this flight time can be measured directly, or after a conversion into a phase shift, or into a beat frequency. We prose here a criterion based on signal processing notions, as matched filtering to get the best detection, and ambiguity function to estimate the quality of the detection. The concept of characteristic length is introduced and applied to the different kind of laser range finders, which suggest a new possibility for flight time measurement.
Neutron yield and Lawson criterion for plasma with inertial electrostatic confinement
NASA Astrophysics Data System (ADS)
Gus'kov, S. Yu; Kurilenkov, Yu K.
2016-11-01
The physics of plasma formation is discussed in the systems with inertial electrostatic confinement (IEC) during the convergent to the axis of cylindrical geometry of the ion flow accelerated periodically in the field of virtual cathode, which is formed by the injected electrons. The ranges of plasma parameters and the resulting neutron yield are determined for different modes of ion flux formation. The requirements are formulated to the technical parameters of the system with IEC to create both a powerful neutron source with a rate of generation exceeding 1010-1012 particles/s and to achieve a positive energy output (analogue of Lawson criterion).
A simple model of thermal crack pattern formation using the coupled criterion
NASA Astrophysics Data System (ADS)
Leguillon, Dominique
2013-06-01
Different mechanisms (cooling, drying, and ageing) lead to the formation of crack patterns on the surface of some materials that are very difficult to describe in detail. We propose a model based on the coupled criterion using two necessary conditions for the nucleation of cracks: an energy condition and a stress condition. This model is applied to a simple example: a plate fixed to a rigid substrate and cooled down on its top face. During slow cooling, it highlights the ability of forming a first lattice of cracks and the subdivision thereof. It also shows that, in a rapid cooling (quenching), the higher the temperature drop, the tighter the cracks network.
Searchless tuning of linear controllers for the minimum of quadratic criterion
NASA Astrophysics Data System (ADS)
Pikina, G. A.; Burtseva, Yu. S.
2014-03-01
A searchless method of calculating the tunings of typical controllers is developed for linear plants with a time delay, the use of which makes it possible to minimize the quadratic criterion I 2 with respect to an internal disturbance. The basic idea of the method consists in obtaining the complex frequency response of a suboptimal linear controller, followed by approaching the characteristic of a typical controller to this frequency response in the essential frequency band using the least squares method. Recommendations on selecting the smoothing filter time constant and the suboptimal system's dynamic error are given for a system comprising a PID controller and a second-order plant with a time delay.
Remarks on the blow-up criterion of the three-dimensional Euler equations
NASA Astrophysics Data System (ADS)
Chae, Dongho
2005-05-01
In this paper we prove that the finite time blow-up of classical solutions of the three-dimensional homogeneous incompressible Euler equations are controlled by the Besov space, \\dot{B}^0_{\\infty, 1} , norm of the two components of the vorticity. For the axisymmetric flows with swirl we deduce that the blow-up of solution is controlled by the same Besov space norm of the angular component of the vorticity. For a proof of these results we use the Beale-Kato-Majda criterion, and the special structure of the vortex stretching term in the vorticity formulation of the Euler equations.
A Beale-Kato-Majda Criterion for Three Dimensional Compressible Viscous Heat-Conductive Flows
NASA Astrophysics Data System (ADS)
Sun, Yongzhong; Wang, Chao; Zhang, Zhifei
2011-08-01
We prove a blow-up criterion in terms of the upper bound of ( ρ, ρ -1, θ) for a strong solution to three dimensional compressible viscous heat-conductive flows. The main ingredient of the proof is an a priori estimate for a quantity independently introduced in Haspot (Regularity of weak solutions of the compressible isentropic Navier-Stokes equation, arXiv:1001.1581, 2010) and Sun et al. (J Math Pure Appl 95:36-47, 2011), whose divergence can be viewed as the effective viscous flux.
NASA Astrophysics Data System (ADS)
Kogoj, Alessia E.
2017-02-01
We show how to apply harmonic spaces potential theory in the study of the Dirichlet problem for a general class of evolution hypoelliptic partial differential equations of second order. We construct Perron-Wiener solution and we provide a sufficient condition for the regularity of the boundary points. Our criterion extends and generalizes the classical parabolic-cone criterion for the Heat equation due to Effros and Kazdan.
Eriksen, B O; Ingebretsen, O C
2007-11-01
The Kidney Disease Outcomes Quality Initiative definition and staging of chronic kidney disease (CKD) have been adopted by most nephrologists but include a criterion of chronicity that has not been investigated. This criterion specifies that renal structural damage and/or reduction in glomerular filtration rate (GFR) should be present for periods lasting longer than 3 months. We examined the effects of changing this criterion to 6, 9, or 12 months on the prognosis and the rate of progression in population-based cohorts with CKD stages 3 and 4. A 12-month chronicity criterion significantly reduced the number of CKD patients relative to the 3-month criterion for both stages 3 and 4. For both stages, there were statistically significant differences in 5-year mortality between the 6- and 9-month cohorts. For stage 4, the 5-year cumulative incidence of renal failure significantly increased from 6 to 9 months, and the rate of change in GFR significantly decreased between the same two cohorts. The 5-year cumulative incidence of improvement in GFR lasting 1 year or more was significantly higher for the 3-month cohort than for the 12-month cohort in the stage 3 group. Hence, we suggest that the chronicity criterion is an important determinant of the characteristics of the population of patients with CKD stages 3 and 4. This may have practical consequences in both research and clinical work.
NASA Astrophysics Data System (ADS)
Goncharenko, Igor V.; Rostovtseva, Vera V.
2006-11-01
Investigation of the conditions resulting in generation of tropical cyclones is the important scientific and practical problem. The suggested temperature-humidity criterion (Pelevin criterion) allows estimating the possibility of tropical cyclone generation using values of ocean surface temperature, water vapor amount above the ocean surface and Coriolis parameter depending on the place latitude. All these parameters can be measured with success by microwave radiometry methods, satellite microwave scanner data giving the possibility to examine the distribution of these physical parameters over different aquatoria of World Ocean and to follow their alteration within the day. To realize this possibility the program of the satellite information processing was developed allowing to estimate such parameters as ocean surface temperature, wind velocity, water vapor amount, amount of water in liquid state (fog), presence and intensity of raining in different areas of World ocean and to obtain the values of Pelevin criterion. Processing measurements of DMSP satellites system there is an opportunity to estimate the abovementioned parameters values and Pelevin criterion twice a day with the spatial resolution of 25X25 km. Distribution of Pelevin criterion value in the tropical Atlantic was analyzed for 2002 and 2004, spatial and time characteristics of statistics of this distribution being revealed. Rather good correlation between the criterion values and the frequency of tropical cyclones generation taking place in Northern Atlantic at these time periods is shown.s
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.
A temperature dependent fatigue failure criterion for graphite/epoxy laminates
NASA Technical Reports Server (NTRS)
Rotem, A.; Nelson, H. G.
1979-01-01
A fatigue failure criterion applicable to composite materials is developed and applied to predict the fatigue behavior of graphite/epoxy laminates with particular emphasis on the influence of temperature. Tensile stress-strain curves and tension-tension fatigue curves for various unidirectional, angle-ply and symmetrically balanced laminates were developed at test temperatures of 25 C, 74 C and 114 C. In general for most laminates a reduction in both static strength and fatigue strength is observed with increasing temperature. This reduction appeared more severe in fatigue loading than in static tensile loading and most severe where the shear stress in the lamina is the dominant failure mode. Through an analytical formulation of shifting functions for the influences of temperature, all fatigue data are shown to be capable of being reduced to a single reference curve at some temperature. Additionally, examples are given which demonstrate the capability of the fatigue failure criterion to predict failure of complex symmetrically balanced laminates from relevant parameters obtained from the observed behavior of unidirectional and angle-ply laminates.
A temperature dependent fatigue failure criterion for graphite/epoxy laminates
NASA Technical Reports Server (NTRS)
Rotem, A.; Nelson, H. G.
1978-01-01
A fatigue failure criterion applicable to composite materials is developed and applied to predict the fatigue behavior of graphite/epoxy laminates with particular emphasis on the influence of temperature. Tensile stress-strain curves and tension-tension fatigue curves for various unidirectional, angle-ply and symmetrically balanced laminates were developed at test temperatures of 25 C, 74 C, and 114 C. For most laminates a reduction in both static strength and fatigue strength is observed with increasing temperature. This reduction appeared more severe in fatigue loading than in static tensile loading and most severe where the shear stress in the lamina is the dominate failure mode. Through an analytical formulation of shifting functions for the influences of temperature, all fatigue data are shown to be capable of being reduced to a single reference curve at some temperature. Examples are given which demonstrate the capability of the fatigue failure criterion to predict failure of complex symmetrically balanced laminates from relevant parameters obtained from the observed behavior of unidirectional and angle-ply laminates.
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.
Fragment Production and Survival in Irradiated Disks: A Comprehensive Cooling Criterion
NASA Astrophysics Data System (ADS)
Kratter, Kaitlin M.; Murray-Clay, Ruth A.
2011-10-01
Accretion disks that become gravitationally unstable can fragment into stellar or substellar companions. The formation and survival of these fragments depends on the precarious balance between self-gravity, internal pressure, tidal shearing, and rotation. Disk fragmentation depends on two key factors: (1) whether the disk can get to the fragmentation boundary of Q = 1 and (2) whether fragments can survive for many orbital periods. Previous work suggests that to reach Q = 1, and have fragments survive, a disk must cool on an orbital timescale. Here we show that disks heated primarily by external irradiation always satisfy the standard cooling time criterion. Thus, even though irradiation heats disks and makes them more stable in general, once they reach the fragmentation boundary, they fragment more easily. We derive a new cooling criterion that determines fragment survival and calculate a pressure-modified Hill radius, which sets the maximum size of pressure-supported objects in a Keplerian disk. We conclude that fragmentation in protostellar disks might occur at slightly smaller radii than previously thought and recommend tests for future simulations that will better predict the outcome of fragmentation in real disks.
Chang, Bonny; Sharp, Carla; Ha, Carolyn
2011-08-01
The purpose of the current study was to examine the criterion validity of the Borderline Personality Features Scale for Children (BPFS-C) by assessing the performance of the self-report and a newly developed parent report version of the measure (BPFS-P) in detecting a borderline personality disorder (BPD) diagnosis in adolescent inpatients. This study also examined parent-child agreement and the internal consistency of the BPFS subscales. An inpatient sample of adolescents (n = 51) ranging from ages 12-18 completed the BPFS and were administered the Child Interview for DSM-IV Borderline Personality Disorder (CI-BPD) by trained clinical research staff. ROC analyses revealed that the BPFS-C has high accuracy (AUC = .931; Se = .856; Sp = .840) in discriminating adolescents with a diagnosis of BPD, as measured by the CI-BPD, while the BPFS-P has moderate accuracy (AUC = .795; Se = .733; Sp = .720). Parent-child agreement on total scores was significant (r = .687; p < .005). Cronbach's alphas suggested internal consistency for the four subscales of the BPFS. These findings support the criterion validity of this measure, particularly the self-report version, in adolescent inpatient settings.
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.
The criterion-related validity of integrity tests: an updated meta-analysis.
Van Iddekinge, Chad H; Roth, Philip L; Raymark, Patrick H; Odle-Dusseau, Heather N
2012-05-01
Integrity tests have become a prominent predictor within the selection literature over the past few decades. However, some researchers have expressed concerns about the criterion-related validity evidence for such tests because of a perceived lack of methodological rigor within this literature, as well as a heavy reliance on unpublished data from test publishers. In response to these concerns, we meta-analyzed 104 studies (representing 134 independent samples), which were authored by a similar proportion of test publishers and non-publishers, whose conduct was consistent with professional standards for test validation, and whose results were relevant to the validity of integrity-specific scales for predicting individual work behavior. Overall mean observed validity estimates and validity estimates corrected for unreliability in the criterion (respectively) were .12 and .15 for job performance, .13 and .16 for training performance, .26 and .32 for counterproductive work behavior, and .07 and .09 for turnover. Although data on restriction of range were sparse, illustrative corrections for indirect range restriction did increase validities slightly (e.g., from .15 to .18 for job performance). Several variables appeared to moderate relations between integrity tests and the criteria. For example, corrected validities for job performance criteria were larger when based on studies authored by integrity test publishers (.27) than when based on studies from non-publishers (.12). In addition, corrected validities for counterproductive work behavior criteria were larger when based on self-reports (.42) than when based on other-reports (.11) or employee records (.15).
Failure criterion of silver nanowire electrodes on a polymer substrate for highly flexible devices
Kim, Donggyun; Kim, Sung-Hoon; Kim, Jong Hak; Lee, Jae-Chul; Ahn, Jae-Pyoung; Kim, Sang Woo
2017-01-01
Nanomechanical characteristics of standalone silver nanowires (Ag NWs) are a key issue for providing a failure criterion of advanced flexible electrodes that are trending towards smaller radius of curvatures (ROCs). Through in-situ tensile and buckling tests of pentagonal Ag NWs, we demonstrated that the intrinsic fracture strain provides a significant criterion to predict the mechanical and electrical failure of Ag NW electrodes under various strain modes, because the decrease in fracture strain limits figure of merit of flexible devices. The Ag NW electrodes on a polymer substrate exhibited a strain-dependent electrical failure owing to the unique deformation characteristics with a size-dependent brittle-to-ductile transition of the five-fold twinned Ag NWs. All the Ag NWs greater than approximately 40 nm in diameter exhibited brittle fracture with a size-independent stress-strain response under tensile and buckling modes, which leads to the electrical failure of flexible electrodes at the almost same threshold ROC. Meanwhile, the higher ductility of Ag NWs less than 40 nm in diameter resulted in much smaller threshold ROCs of the electrodes due to the highly extended fracture strains, which can afford a high degree of freedom for highly flexible devices. PMID:28378763
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.
Criterion for the dynamical stability of a non-adiabatic spherical self-gravitating body
NASA Astrophysics Data System (ADS)
Stothers, Richard B.
1999-04-01
Why do stars and planets maintain their dynamical stability over cosmically long periods of time? The standard answer is that the first generalized adiabatic exponent of their material, Gamma_1, exceeds the value 4/3. Yet it has never been rigorously demonstrated (except for the simple one-zone model) that non-adiabatic effects do not modify this result at some level. Many authors, in fact, have suggested the probable need for a non-adiabatic correction to the square of the radial adiabatic eigenfrequency, sigma^2, which ostensibly governs dynamical stability in the more general case where Gamma_1 varies throughout a fully distributed self-gravitating spherical body. Here, a carefully controlled series of numerical experiments based on linear and non-linear hydrodynamical models of highly non-adiabatic spherically symmetric stellar envelopes (mimicking the envelopes of luminous blue variables) confirms, quite generally, that the purely adiabatic criterion sigma^2>0 does in fact determine dynamical stability. An accurate approximation to this criterion is further shown to be that the volumetric pressure-weighted average of Gamma_1 must exceed 4/3. These results, which concern only radial stability, verify the theoretical basis of the more sophisticated models for luminous blue variables that were constructed by the author and C.-w. Chin, but they do not support the objections to these models raised by W. Glatzel and M. Kiriakidis.
Is DSM-IV criterion A2 associated with PTSD diagnosis and symptom severity?
Osei-Bonsu, Princess E; Spiro, Avron; Schultz, Mark R; Ryabchenko, Karen A; Smith, Eric; Herz, Lawrence; Eisen, Susan V
2012-08-01
The diagnostic criteria for posttraumatic stress disorder (PTSD) have received significant scrutiny. Several studies have investigated the utility of Criterion A2, the subjective emotional response to a traumatic event. The American Psychiatric Association (APA) has proposed elimination of A2 from the PTSD diagnostic criteria for DSM-5; however, there is mixed support for this recommendation and few studies have examined A2 in samples at high risk for PTSD such as veterans. In the current study of 908 veterans who screened positive for a traumatic event, A2 was not significantly associated with having been told by a doctor that the veteran had PTSD. Those who endorsed A2, however, reported greater PTSD symptom severity in the 3 DSM-IV symptom clusters of reexperiencing (d = 0.45), avoidance (d = 0.61), and hyperarousal (d = 0.44), and A2 was significantly associated with PTSD symptom severity for all 3 clusters (R(2) = .25, .25, and .27, respectively) even with trauma exposure in the model. Thus, although A2 may not be a necessary criterion for PTSD diagnosis, its association with PTSD symptom severity warrants further exploration of its utility.
Empathy and the application of the 'unbearable suffering' criterion in Dutch euthanasia practice.
van Tol, Donald G; Rietjens, Judith A C; van der Heide, Agnes
2012-05-01
A pivotal due care criterion for lawful euthanasia in the Netherlands is that doctors must be convinced that a patient requesting for euthanasia, suffers unbearably. Our study aims to find out how doctors judge if a patient suffers unbearably. How do doctors bridge the gap from 3rd person assessment to 1st person experience? We performed a qualitative interview study among 15 physicians, mainly general practitioners, who participated earlier in a related quantitative survey on the way doctors apply the suffering criterion. Results show that doctors follow different 'cognitive routes' when assessing a patients suffering in the context of a euthanasia request. Sometimes doctors do this imagining how she herself would experience the situation of the patient ('imagine self'). Doctors may also try to adopt the perspective of the patient and imagine what the situation is like for this particular patient ('imagine other'). Besides this we found that the (outcome of the) assessment is influenced by a doctor's private norms, values and emotions considering (the performance of) euthanasia. We conclude by arguing why doctors should be aware of both the 'cognitive route' followed as well as the influence of their own personal norms on the assessment of suffering in the context of euthanasia requests.
Chen, Yuhang; Schellekens, Michiel; Zhou, Shiwei; Cadman, Joseph; Li, Wei; Appleyard, Richard; Li, Qing
2011-08-01
Tissue scaffolds aim to provide a cell-friendly biomechanical environment for facilitating cell growth. Existing studies have shown significant demands for generating a certain level of wall shear stress (WSS) on scaffold microstructural surfaces for promoting cellular response and attachment efficacy. Recently, its role in shear-induced erosion of polymer scaffold has also drawn increasing attention. This paper proposes a bi-directional evolutionary structural optimization (BESO) approach for design of scaffold microstructure in terms of the WSS uniformity criterion, by downgrading highly-stressed solid elements into fluidic elements and/or upgrading lowly-stressed fluidic elements into solid elements. In addition to this, a computational model is presented to simulate shear-induced erosion process. The effective stiffness and permeability of initial and optimized scaffold microstructures are characterized by the finite element based homogenization technique to quantify the variations of mechanical properties of scaffold during erosion. The illustrative examples show that a uniform WSS is achieved within the optimized scaffold microstructures, and their architectural and biomechanical features are maintained for a longer lifetime during shear-induced erosion process. This study provides a mathematical means to the design optimization of cellular biomaterials in terms of the WSS criterion towards controllable shear-induced erosion.
NASA Astrophysics Data System (ADS)
Yan, Shuai; Sun, Weichao
2017-09-01
Active suspension systems have advantages on mitigating the effects of vehicle vibration caused by road roughness, which are one of the most important component parts in influencing the performances of vehicles. However, high amount of energy consumption restricts the application of active suspension systems. From the point of energy saving, this paper presents a self-powered criterion of the active suspension system to judge whether a motor-driven suspension can be self-powered or not, and then a motor parameter condition is developed as a reference to design a self-powered suspension. An energy regeneration implementation scheme is subsequently proposed to make the active suspension which has the potential to be self-powered achieve energy-saving target in the real application. In this implementation scheme, operating electric circuits are designed based on different working status of the actuator and power source and it is realizable to accumulate energy from road vibration and supply energy to the actuator by switching corresponding electric circuits. To apply the self-powered suspension criterion and energy regeneration implementation scheme, an active suspension system is designed with a constrained H∞ controller and calculation results indicate that it has the capability to be self-powered. Simulation results show that the performances of the self-powered active suspension are nearly the same as those of the active suspension with an external energy source and can achieve energy regeneration at the same time.
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.
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
Pedrow, P.D.; Olsen, R.G.
1996-12-31
To design hardware for compact high voltage lines it is necessary to predict conditions for which corona streamers are initiated. Existing techniques for optimizing hardware shape and calculating streamer onset are based on corona measurements in a coaxial geometry that uses concentric cylinders for electrodes. Peek`s law shows that the formation of corona streamers is related not only to electric field but also to surface curvature. It is not clear that Peek`s law (developed in a coaxial geometry for which radius of curvature in the axial direction is infinite) is appropriate for designing hardware surfaces which are defined at any point by two finite radii of curvature. In this work the authors seek a corona onset criterion for these more general surfaces which reduces to Peeks law in the limit that one of the radii of curvature is infinite. An existing electrostatic code is being modified to allow for iterative optimization of electrode shapes based on results of previous field calculations. Experimental corona performance testing of electrode shapes will take place in an air-filled chamber with ac voltage as high as 100 kV rms. Experiments will be used to evaluate various electrode shapes designed by the trial optimization criterion.
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
Generalized Bohm’s criterion and negative anode voltage fall in electric discharges
Londer, Ya. I.; Ul’yanov, K. N.
2013-10-15
The value of the voltage fall across the anode sheath is found as a function of the current density. Analytic solutions are obtained in a wide range of the ratio of the directed velocity of plasma electrons v{sub 0} to their thermal velocity v{sub T}. It is shown that the voltage fall in a one-dimensional collisionless anode sheath is always negative. At the small values of v{sub 0}/v{sub T}, the obtained expression asymptotically transforms into the Langmuir formula. Generalized Bohm’s criterion for an electric discharge with allowance for the space charge density ρ(0), electric field E(0), ion velocity v{sub i}(0), and ratio v{sub 0}/v{sub T} at the plasma-sheath interface is formulated. It is shown that the minimum value of the ion velocity v{sub i}{sup *}(0) corresponds to the vanishing of the electric field at one point inside the sheath. The dependence of v{sub i}{sup *} (0) on ρ(0), E(0), and v{sub 0}/v{sub T} determines the boundary of the existence domain of stationary solutions in the sheath. Using this criterion, the maximum possible degree of contraction of the electron current at the anode is determined for a short high-current vacuum arc discharge.
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.
Optimal rate control for video coding based on a hybrid MMAX/MMSE criterion
NASA Astrophysics Data System (ADS)
Lee, Sang-Yong; Ortega, Antonio
2003-05-01
In this paper, we consider the problem of rate control for video transmission. We focus on finding off-line optimal rate control for constant bit-rate (CBR) transmission, where the size of the encoder buffer and the channel rate are the constraints. To ensure a maximum minimum quality is obtained over all data units (e.g., macro blocks, video frames or group-of-pictures), we use a minimum maximum distortion (MMAX) criterion for this buffer-constrained problem. We show that, due to the buffer constraints, a MMAX solution leads to a relatively low average distortion, because the total rate budget is not completely utilized. Therefore, after finding a MMAX solution, an additional minimization of average distortion criterion is proposed to increase overall quality of the data sequence by using remaining resources. The proposed algorithm (denoted MMAX+ as it incorporates both MMAX and the additional average quality optimization stage) leads to an increase in average quality with respect to the MMAX solution, while providing a much more constant quality than MMSE solutions. Moreover we show how the MMAX+ approach can be implemented with low complexity.
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
Failure criterion of silver nanowire electrodes on a polymer substrate for highly flexible devices.
Kim, Donggyun; Kim, Sung-Hoon; Kim, Jong Hak; Lee, Jae-Chul; Ahn, Jae-Pyoung; Kim, Sang Woo
2017-04-05
Nanomechanical characteristics of standalone silver nanowires (Ag NWs) are a key issue for providing a failure criterion of advanced flexible electrodes that are trending towards smaller radius of curvatures (ROCs). Through in-situ tensile and buckling tests of pentagonal Ag NWs, we demonstrated that the intrinsic fracture strain provides a significant criterion to predict the mechanical and electrical failure of Ag NW electrodes under various strain modes, because the decrease in fracture strain limits figure of merit of flexible devices. The Ag NW electrodes on a polymer substrate exhibited a strain-dependent electrical failure owing to the unique deformation characteristics with a size-dependent brittle-to-ductile transition of the five-fold twinned Ag NWs. All the Ag NWs greater than approximately 40 nm in diameter exhibited brittle fracture with a size-independent stress-strain response under tensile and buckling modes, which leads to the electrical failure of flexible electrodes at the almost same threshold ROC. Meanwhile, the higher ductility of Ag NWs less than 40 nm in diameter resulted in much smaller threshold ROCs of the electrodes due to the highly extended fracture strains, which can afford a high degree of freedom for highly flexible devices.
Atomistic potentials based energy flux integral criterion for dynamic adiabatic shear banding
NASA Astrophysics Data System (ADS)
Xu, Yun; Chen, Jun
2015-02-01
The energy flux integral criterion based on atomistic potentials within the framework of hyperelasticity-plasticity is proposed for dynamic adiabatic shear banding (ASB). System Helmholtz energy decomposition reveals that the dynamic influence on the integral path dependence is originated from the volumetric strain energy and partial deviatoric strain energy, and the plastic influence only from the rest part of deviatoric strain energy. The concept of critical shear banding energy is suggested for describing the initiation of ASB, which consists of the dynamic recrystallization (DRX) threshold energy and the thermal softening energy. The criterion directly relates energy flux to the basic physical processes that induce shear instability such as dislocation nucleations and multiplications, without introducing ad-hoc parameters in empirical constitutive models. It reduces to the classical path independent J-integral for quasi-static loading and elastic solids. The atomistic-to-continuum multiscale coupling method is used to simulate the initiation of ASB. Atomic configurations indicate that DRX induced microstructural softening may be essential to the dynamic shear localization and hence the initiation of ASB.
NASA Astrophysics Data System (ADS)
Zheng, Yu-Lin; Zhen, Yi-Zheng; Chen, Zeng-Bing; Liu, Nai-Le; Chen, Kai; Pan, Jian-Wei
2017-01-01
The striking and distinctive nonlocal features of quantum mechanics were discovered by Einstein, Podolsky, and Rosen (EPR) beyond classical physics. At the core of the EPR argument, it was "steering" that Schrödinger proposed in 1935. Besides its fundamental significance, quantum steering opens up a novel application for quantum communication. Recent work has precisely characterized its properties; however, witnessing the EPR nonlocality remains a big challenge under arbitrary local measurements. Here we present an alternative linear criterion and complement existing results to efficiently testify steering for high-dimensional system in practice. By developing a novel and analytical method to tackle the maximization problem in deriving the bound of a steering criterion, we show how observed correlations can reveal powerfully the EPR nonlocality in an easily accessed manner. Although the criteria is not necessary and sufficient, it can recover some of the known results under a few settings of local measurements and is applicable even if the size of the system or the number of measurement settings are high. Remarkably, a deep connection is explicitly established between the steering and amount of entanglement. The results promise viable paths for secure communication with an untrusted source, providing optional loophole-free tests of the EPR nonlocality for high-dimensional states, as well as motivating solutions for other related problems in quantum information theory.
A criterion to classify asteroids and comets based on the orbital parameters
NASA Astrophysics Data System (ADS)
Tancredi, Gonzalo
2014-05-01
The classification criterion between asteroids and comets has evolved in recent decades, but the main distinction remains unchanged. Comets present gas and dust ejection from the surface at some point of their orbits, therefore, these objects are considered to be active. On the other hand, asteroids do not show any kind of large scale gas and dust ejection, they are inert. Nevertheless, this classification scheme is impractical when we have more than 500,000 asteroids already discovered. In addition, comets are not active all along their orbits. In order for a comet to display activity at present or in the recent past in the inner region of the Solar System (heliocentric distance <2 AU), the cometary orbit must be unstable in the time scale on the order of ten thousands of years; otherwise, the object should have completely consumed its volatile component. Close encounters with the most massive planets is the only mechanism that could produce “macroscopic” instabilities on a short time scale. The macroscopic changes in the orbital elements can be detected in a numerical integration of the dynamical evolution of the object over a time scale of several thousand years. This procedure to identify asteroids in cometary-like orbits is also impractical because it would require months of computing time. Therefore, a classification scheme based on the orbital elements to identify the border cases between the asteroid and comet populations is urgently required. We present a criterion to classify asteroids and comets and to find the border case based on the Tisserand’s parameter, the Minimum Orbital Intersection Distance (MOID), and considering some information regarding the aphelion and perihelion distances. Objects in mean-motion are disregarded. After applying a filter to the sample of over half a million asteroids already discovered to select the precise orbits and to the sample of 487 short-period comets, we apply the proposed classification criterion. The
Pfaffel, Andreas; Kollmayer, Marlene; Schober, Barbara; Spiel, Christiane
2016-01-01
A recurring methodological problem in the evaluation of the predictive validity of selection methods is that the values of the criterion variable are available for selected applicants only. This so-called range restriction problem causes biased population estimates. Correction methods for direct and indirect range restriction scenarios have widely studied for continuous criterion variables but not for dichotomous ones. The few existing approaches are inapplicable because they do not consider the unknown base rate of success. Hence, there is a lack of scientific research on suitable correction methods and the systematic analysis of their accuracies in the cases of a naturally or artificially dichotomous criterion. We aim to overcome this deficiency by viewing the range restriction problem as a missing data mechanism. We used multiple imputation by chained equations to generate complete criterion data before estimating the predictive validity and the base rate of success. Monte Carlo simulations were conducted to investigate the accuracy of the proposed correction in dependence of selection ratio, predictive validity, and base rate of success in an experimental design. In addition, we compared our proposed missing data approach with Thorndike’s well-known correction formulas that have only been used in the case of continuous criterion variables so far. The results show that the missing data approach is more accurate in estimating the predictive validity than Thorndike’s correction formulas. The accuracy of our proposed correction increases as the selection ratio and the correlation between predictor and criterion increase. Furthermore, the missing data approach provides a valid estimate of the unknown base rate of success. On the basis of our findings, we argue for the use of multiple imputation by chained equations in the evaluation of the predictive validity of selection methods when the criterion is dichotomous. PMID:27019277
Assessment of the pubic force as a pelvic injury criterion in side impact.
Leport, Tiphaine; Baudrit, Pascal; Trosseille, Xavier; Petit, Philippe; Palisson, Anna; Vallancien, Guy
2007-10-01
In the literature, injuries at the ischio or ilio pubic ramus level are reported to occur to approximately (3/4) of the occupants injured at the pelvis during side impact. Assuming that the load going through the pubis was a good indicator of the ramus stress, the pubic force was widely accepted as a protection criterion for pelvic fractures on side impact dummies. However, no data regarding the actual loads going through the pubis is currently available in the literature for Post Mortem Human Subjects (PMHS) in dynamic conditions. The goal of this study was to determine pelvic biofidelity specifications in terms of load path, to evaluate the pertinence of the pubic force as a criterion, and to develop a pelvic injury risk curve as a function of the pubic force. For that purpose, a pubic load cell was developed for PMHS use, and 16 side impact tests were performed on 8 PMHS using boundary conditions similar to impactor tests and sled tests reported in the literature. One kind of impact was applied on one side of a subject and the other kind of impact was then applied on the other side of the same subject, at non injury severities. The ratio between the peak external force and the peak pubic force was calculated for each subject, and a mean ratio was then calculated for each of the test conditions. These ratios were finally used to calculate the pubic forces from the external pelvic forces for 90 PMHS side impact test data available in the literature. Injury risk curves as a function of the pubic force were developed from these data. Two normalized pubic force corridors from the 16 tests are presented, the first one for the impactor tests, the second one for the sled-like tests. The test results show statistically different ratios between the peak external force and the peak pubic force, for the two configurations (an average ratio of 3.3 for impactor tests and 4.6 for sled-like tests). The PMHS injury risk curves based on the external pelvic force were observed to
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
NASA Astrophysics Data System (ADS)
Yu, Zong-Han; Wu, Chun-Ming; Lin, Yo-Wei; Chuang, Ming-Lung; Tsai, Jui-che; Sun, Chia-Wei
2008-02-01
Diffuse optical tomography (DOT) is an emerging technique for biomedical imaging. The imaging quality of the DOT strongly depends on the reconstruction algorithm. In this paper, four inhomogeneities with various shapes of absorption distributions are simulated by a continues-wave DOT system. The DOT images are obtained based on the simultaneous iterative reconstruction technique (SIRT) method. To solve the trade-off problem between time consumption of reconstruction process and accuracy of reconstructed image, the iteration process needs a optimization criterion in algorithm. In this paper, the comparison between the root mean square error (RMSE) and the convergence rate (CR) in SIRT algorithm are demonstrated. From the simulation results, the CR reveals the information of global minimum in the iteration process. Based on the CR calculation, the SIRT can offer higher efficient image reconstructing in DOT system.
Martland, Jarrad; Chamberlain, Diane; Hutton, Alison; Smigielski, Michael
2015-11-30
Objective Patients commonly show signs and symptoms of deterioration for hours or days before cardiorespiratory arrest. Rapid response teams (RRT) were created to improve recognition and response to patient deterioration in these situations. Activation criteria include vital signs or 'general concern' by a clinician or family member. The general concern criterion for RRT activation accounts for nearly one-third of all RRT activity, and although it is well established that communication deficits between staff can contribute to poorer outcomes for patients, there is little evidence pertaining to communication and its effects on the general concern RRT activation. Thus, the aim of the present study was to develop a substantive grounded theory related to the communication process between clinicians that preceded the activation of an RRT when general concern criterion was used.Methods Qualitative grounded theory involved collection of three types of data details namely personal notes from participants in focus groups with white board notes from discussions and audio recordings of the focus groups sessions. Focus groups were conducted with participants exploring issues associated with clinician communication and how it related to the activation of an RRT using the general concern criterion.Results The three main phases of coding (i.e. open, axial and selective coding) analysis identified 322 separate open codes. The strongest theme contributed to a theory of ineffective communication and decreased psychological safety, namely that 'In the absence of effective communication there is a subsequent increase in anxiety, fear or concern that can be directly attributed to the activation of an RRT using the 'general concern' criterion'. The RRT filled cultural and process deficiencies in the compliance with an escalation protocol. Issues such as 'not for resuscitation documentation' and 'inability to establish communication with and between medical or nursing personnel' rated
A Study on Electrical Reliability Criterion on Through Silicon Via Packaging.
Lwo, Ben-Je; Tseng, Kuo-Hao; Tseng, Kun-Fu
2016-06-01
Three-dimensional (3D) structure with through silicon via (TSV) technology is emerging as a key issue in microelectronic packaging industry, and electrical reliability has become one of the main technical subjects for the TSV designs. However, criteria used for TSV reliability tests have not been consistent in the literature, so that the criterion itself becomes a technical argument. To this end, this paper first performed several different reliability tests on the testing packaging with TSV chains, then statistically analyzed the experimental data with different failure criteria on resistance increasing, and finally constructed the Weibull failure curves with parameter extractions. After comparing the results, it is suggested that using different criteria may lead to the same failure mode on Weibull analyses, and 65% of failed devices are recommended as a suitable termination for reliability tests.
Evaluation of closed cubic failure criterion for graphite/epoxy laminates
NASA Technical Reports Server (NTRS)
Tennyson, R. C.; Jiang, Zhiqing
1987-01-01
An analytical method has been developed to ensure closure of the cubic form of the tensor polynomial strength criterion. The intrinsic complexity of the cubic function is such that special conditions must be met to close the failure surface in three-dimensional stress space. These requirements are derived in terms of non-intersecting conditions for asymptotes and an asymptotic plane. To demonstrate the validity of this approach, closed failure surfaces were derived for two graphite/epoxy material systems (3M SP288-T300 and IM7 8551-7). The agreement of test data with this model clearly shows that it is possible to use a higher order cubic failure theory with confidence.
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.
Rocznik, Dorothee; Sinn, David L; Thomas, Scott; Gosling, Samuel D
2015-01-01
Many working-dog programs assess behavior during a dog's first year of life with the aim of predicting success in the field. However, decisions about which tests to administer are frequently made on the basis of tradition or intuition. This study reports results from a survey given to U.S.A.'s Transportation Security Administration (TSA) detection-dog handlers (N = 34). We categorized and summarized handlers' responses regarding traits they felt were important for work. We used this criterion analysis to examine the content validity of the TSA's puppy tests. Results indicate that 13 of 15 traits that are currently being measured are relevant. However, several traits not currently measured were identified as being highly important, notably "play" and off-duty "calmness." These results provide support that the TSA tests are measuring traits relevant to operational search team performance but also highlight other traits that may be profitable to assess in this and other detection-dog programs.
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.
A criterion for intergranular failure during hot working of a near-gamma titanium aluminide alloy
Semiatin, S.L.; Seetharaman, V.
1997-02-01
Because they are designed for high-temperature service, intermetallic alloys can be difficult to manufacture via conventional hot-working operations. The processing window in terms of strain rates and temperatures that may be utilized to produce sound products of these materials is usually quite narrow. Such problems can be especially severe for ingot-cast forms of these alloys which consist of relatively coarse-grain microstructures. The objective of the present work was to begin the development of models for the hot workability of near-gamma titanium aluminide alloys under high-rate deformation conditions that characterize conventional metalworking processes. For this purpose, isothermal, hot compression test results for a typical near-gamma titanium aluminide were analyzed to formulate a criterion for the formation of wedge cracks in these materials.
Spatiotemporal generalization of the Harris criterion and its application to diffusive disorder.
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.
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.
The diagnostic line: A novel criterion for condition monitoring of rotating machinery.
Lin, Jinshan; Dou, Chunhong
2015-11-01
This study examined scaling properties of an increment series from rotating machinery. Moreover, two fluctuation parameters for the smallest and largest time scales of a scaling range served as a pair of fluctuation parameters to describe system conditions. Therefore, an interesting phenomenon is observed: the data points, each representing a pair of fluctuation parameters, for fault conditions almost form a straight line, while those for normal clearly depart from the straight line. To describe the phenomenon, a novel concept termed the diagnostic line was introduced. Subsequently, properties of the diagnostic line were carefully investigated theoretically and numerically. Consequently, a decisive role of noise in forming the diagnostic line was determined. Accordingly, this study develops a novel criterion for condition monitoring of rotating machinery.
A variational dynamic programming approach to robot-path planning with a distance-safety criterion
NASA Technical Reports Server (NTRS)
Suh, Suk-Hwan; Shin, Kang G.
1988-01-01
An approach to robot-path planning is developed by considering both the traveling distance and the safety of the robot. A computationally-efficient algorithm is developed to find a near-optimal path with a weighted distance-safety criterion by using a variational calculus and dynamic programming (VCDP) method. The algorithm is readily applicable to any factory environment by representing the free workspace as channels. A method for deriving these channels is also proposed. Although it is developed mainly for two-dimensional problems, this method can be easily extended to a class of three-dimensional problems. Numerical examples are presented to demonstrate the utility and power of this method.
NASA Astrophysics Data System (ADS)
Niwa, M.; Alves, N. C.; Caetano, A. O.; Andrade, N. S. O.
2012-01-01
The recent advent of the commercial launch and re- entry activities, for promoting the expansion of human access to space for tourism and hypersonic travel, in the already complex ambience of the global space activities, brought additional difficulties over the development of a harmonized framework of international safety rules. In the present work, with the purpose of providing some complementary elements for global safety rule development, the certification-related activities conducted in the Brazilian space program are depicted and discussed, focusing mainly on the criterion for certification basis compilation. The results suggest that the composition of a certification basis with the preferential use of internationally-recognized standards, as is the case of ISO standards, can be a first step toward the development of an international safety regulation for commercial space activities.
Information-criterion based selection of models for community noise annoyance.
Keith Wilson, D; Valente, Dan; Nykaza, Edward T; Pettit, Chris L
2013-03-01
Statistical evidence for various models relating day-night sound level (DNL) to community noise annoyance is assessed with the Akaike information criterion. In particular, community-specific adjustments such as the community tolerance level (CTL, the DNL at which 50% of survey respondents are highly annoyed) and community tolerance spread (CTS, the difference between the DNL at which 90% and 10% are highly annoyed) are considered. The results strongly support models characterizing annoyance on a community-by-community basis, rather than with complete pooling and analysis of all available surveys. The most likely model was found to be a 2-parameter logistic model, with CTL and CTS fit independently to survey data from each community.
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.
"Visually clean" as a sole acceptance criterion for cleaning validation protocols.
LeBlanc, Destin A
2002-01-01
The role of visual examination as the sole acceptance criterion in cleaning validation protocols is explored, including the proper definition of "visual limit" for a given residue. Such a visual limit is specific to the surface the residue is on, and is further defined by viewing conditions, such as lighting, distance, and angle of viewing. A visually clean standard may only be properly utilized if the visual limit is below any scientifically calculated residue limit, such as that determined by a traditional dose-based limit determination. While such an approach, properly applied, has scientific justification and appears to be accepted by the proposed Annex 15 to the European GMPs, the approach is still untested with regulatory authorities.
Flat-fielding of Solar Hα Observations Based on the Maximum Correntropy Criterion
NASA Astrophysics Data System (ADS)
Xu, Gao-Gui; Zheng, Sheng; Lin, Gang-Hua; Wang, Xiao-Fan
2016-08-01
The flat-field CCD calibration method of Kuhn et al. (KLL) is an efficient method for flat-fielding. However, since it depends on the minimum of the sum of squares error (SSE), its solution is sensitive to noise, especially non-Gaussian noise. In this paper, a new algorithm is proposed to determine the flat field. The idea is to change the criterion of gain estimate from SSE to the maximum correntropy. The result of a test on simulated data demonstrates that our method has a higher accuracy and a faster convergence than KLL’s and Chae’s. It has been found that the method effectively suppresses noise, especially in the case of typical non-Gaussian noise. And the computing time of our algorithm is the shortest.
Stahl, Sarah T; Insana, Salvatore P
2014-11-01
Criterion validity of a novel accelerometry device that measures caloric expenditure (Fitbit) was evaluated against a self-report estimation of caloric expenditure (Community Healthy Activities Model Program for Seniors) in older adults. Community Health Activities Model Program for Seniors and Fitbit estimates of total caloric expenditure per day were significantly correlated (r = .61, p < .05). Bland-Altman plots indicated that 70 percent of participants' data were within 1 standard deviation of the mean difference between measures. These preliminary findings suggest that the Fitbit may be considered a viable instrument for measuring daily caloric expenditure among older adults. However, further work is required to determine the optimal measurement technique for caloric expenditure among older adults.
NASA Technical Reports Server (NTRS)
Crowe, D. R.; Henricks, W.
1983-01-01
The combined load statistics are developed by taking the acoustically induced load to be a random population, assumed to be stationary. Each element of this ensemble of acoustically induced loads is assumed to have the same power spectral density (PSD), obtained previously from a random response analysis employing the given acoustic field in the STS cargo bay as a stationary random excitation. The mechanically induced load is treated as either (1) a known deterministic transient, or (2) a nonstationary random variable of known first and second statistical moments which vary with time. A method is then shown for determining the probability that the combined load would, at any time, have a value equal to or less than a certain level. Having obtained a statistical representation of how the acoustic and mechanical loads are expected to combine, an analytical approximation for defining design levels for these loads is presented using the First Passage failure criterion.
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.
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.
Robust SDRE filter design for nonlinear uncertain systems with an H∞ performance criterion.
Beikzadeh, Hossein; Taghirad, Hamid D
2012-01-01
In order to remedy the effects of modeling uncertainty, measurement noise and input disturbance on the performance of the standard state-dependent Riccati equation (SDRE) filter, a new robust H(∞) SDRE filter design is developed in this paper. Based on the infinity-norm minimization criterion, the proposed filter effectively estimates the states of nonlinear uncertain system exposed to unknown disturbance inputs. Moreover, by assuming a mild Lipschitz condition on the chosen state-dependent coefficient form, fulfillment of a modified H(∞) performance index is guaranteed in the proposed filter. The effectiveness of the robust SDRE filter is demonstrated through numerical simulations where it brilliantly outperforms the conventional SDRE filter in presence of model uncertainties, disturbance and measurement noise, in terms of estimation error and region of convergence.
A CRITERION FOR RAPID RATIONAL APPROXIMATION IN \\mathbf{C}^n
NASA Astrophysics Data System (ADS)
Sadullaev, A.
1986-02-01
This article gives a necessary and sufficient condition for a function which is holomorphic in a neighborhood of zero to belong to the class R^0. This criterion, which is formulated in terms of the Taylor coefficients of the function, is then applied to give a description of the singular set of holomorphic functions of several variables which admit rapid rational approximation relative to Lebesgue measure (i.e., which belongs to the class R^0). In particular,Theorem. If \\mathscr{O}(D)\\subset R^0, then the complement \\mathbf{C}^n\\setminus\\hat D of the envelope of holomorphy \\hat D is a pluripolar set.This theorem together with a well-known result of A. A. Gonchar gives a complete description of the domains for which \\mathscr{O}(D)\\subset R^0: this property is satisfied if and only if \\mathbf{C}^n\\setminus\\hat D is a pluripolar set.Bibliography: 11 titles.
Shi, Ming; Shen, Weiming; Wang, Hong-Qiang; Chong, Yanwen
2016-12-01
Inferring gene regulatory networks (GRNs) from microarray expression data are an important but challenging issue in systems biology. In this study, the authors propose a Bayesian information criterion (BIC)-guided sparse regression approach for GRN reconstruction. This approach can adaptively model GRNs by optimising the l1-norm regularisation of sparse regression based on a modified version of BIC. The use of the regularisation strategy ensures the inferred GRNs to be as sparse as natural, while the modified BIC allows incorporating prior knowledge on expression regulation and thus avoids the overestimation of expression regulators as usual. Especially, the proposed method provides a clear interpretation of combinatorial regulations of gene expression by optimally extracting regulation coordination for a given target gene. Experimental results on both simulation data and real-world microarray data demonstrate the competent performance of discovering regulatory relationships in GRN reconstruction.
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.
On signal design by the R/0/ criterion for non-white Gaussian noise channels
NASA Technical Reports Server (NTRS)
Bordelon, D. L.
1977-01-01
The use of the cut-off rate criterion for modulation system design is investigated for channels with non-white Gaussian noise. A signal space representation of the waveform channel is developed, and the cut-off rate for vector channels with additive non-white Gaussian noise and unquantized demodulation is derived. When the signal input to the channel is a continuous random vector, maximization of the cut-off rate with constrained average signal energy leads to a water-filling interpretation of optimal energy distribution in signal space. The necessary condition for a finite signal set to maximize the cut-off rate with constrained energy and an equally likely probability assignment of signal vectors is presented, and an algorithm is outlined for numerically computing the optimum signal set. As an example, the rectangular signal set which has the water-filling average energy distribution and the optimum rectangular set are compared.
PID controller auto-tuning based on process step response and damping optimum criterion.
Pavković, Danijel; Polak, Siniša; Zorc, Davor
2014-01-01
This paper presents a novel method of PID controller tuning suitable for higher-order aperiodic processes and aimed at step response-based auto-tuning applications. The PID controller tuning is based on the identification of so-called n-th order lag (PTn) process model and application of damping optimum criterion, thus facilitating straightforward algebraic rules for the adjustment of both the closed-loop response speed and damping. The PTn model identification is based on the process step response, wherein the PTn model parameters are evaluated in a novel manner from the process step response equivalent dead-time and lag time constant. The effectiveness of the proposed PTn model parameter estimation procedure and the related damping optimum-based PID controller auto-tuning have been verified by means of extensive computer simulations.
NASA Astrophysics Data System (ADS)
Liu, Jian; Li, Mengzhou; Li, Qiang; Tan, Jiubin
2016-12-01
In confocal metrology, the lateral and axial responses are coupled in narrow regions near groove edges. This coupling results in an area with an uncertain profile, particularly for measurements of tight structures or deep grooves. In this paper, to delineate the area with measurement accuracy loss, an analytical model depicting the coupling relationships between the groove depth, the coupled portions and the NA of the objective used is introduced. Based on this model, the limited energy lost (LEL) decoupling criterion is presented that can enable users to choose suitable numerical apertures before performing measurements, predict the extents of the areas with measurement accuracy loss, and identify readout areas that yield accurate height measurements. The theory was verified by using confocal microscopes and is also applicable to far-field optical scanning metrology.
MINVAR: a local optimization criterion for rate-distortion tradeoff in real time video coding
NASA Astrophysics Data System (ADS)
Chen, Zhenzhong; Ngan, King Ngi
2005-10-01
In this paper, we propose a minimum variation (MINVAR) distortion criterion based approach for the rate distortion tradeoff in video coding. The MINVAR based rate distortion tradeoff framework provides a local optimization strategy as a rate control mechanism in real time video coding applications by minimizing the distortion variation while the corresponding bit rate fluctuation is limited by utilizing the encoder buffer. We use the H.264 video codec to evaluate the performance of the proposed method. As shown in the simulation results, the decoded picture quality of the proposed approach is smoother than that of the traditional H.264 joint model (JM) rate control algorithm. The global video quality, the average PSNR, is maintained while a better subjective visual quality is guaranteed.
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.
Chapman, Benjamin P.; Weiss, Alexander; Duberstein, Paul
2016-01-01
Statistical learning theory (SLT) is the statistical formulation of machine learning theory, a body of analytic methods common in “big data” problems. Regression-based SLT algorithms seek to maximize predictive accuracy for some outcome, given a large pool of potential predictors, without overfitting the sample. Research goals in psychology may sometimes call for high dimensional regression. One example is criterion-keyed scale construction, where a scale with maximal predictive validity must be built from a large item pool. Using this as a working example, we first introduce a core principle of SLT methods: minimization of expected prediction error (EPE). Minimizing EPE is fundamentally different than maximizing the within-sample likelihood, and hinges on building a predictive model of sufficient complexity to predict the outcome well, without undue complexity leading to overfitting. We describe how such models are built and refined via cross-validation. We then illustrate how three common SLT algorithms–Supervised Principal Components, Regularization, and Boosting—can be used to construct a criterion-keyed scale predicting all-cause mortality, using a large personality item pool within a population cohort. Each algorithm illustrates a different approach to minimizing EPE. Finally, we consider broader applications of SLT predictive algorithms, both as supportive analytic tools for conventional methods, and as primary analytic tools in discovery phase research. We conclude that despite their differences from the classic null-hypothesis testing approach—or perhaps because of them–SLT methods may hold value as a statistically rigorous approach to exploratory regression. PMID:27454257
Risser, R; Chaloupka, Ch; Grundler, W; Sommer, M; Häusler, J; Kaufmann, C
2008-01-01
In several countries in Europe (among others Germany and Austria) persons who have lost their drivers licence have to undergo a psychological test in order to regain their licence. The article discusses the validity of two test batteries of the Expert System Traffic using standardized driving tests [Schuhfried, G., 2005. Manual Expert System Traffic (XPSV). Schuhfried GmbH, Mödling]. A global evaluation of the respondents' performance in a standardized driving test was used as criterion measure in order to divide the subjects into drivers, who were classified as relatively safe or unsafe according to their performance in a standardized driving test. Artificial neural networks were used to calculate the criterion validity. This yielded superior classification rates and validity coefficients compared to classical multivariate methods such as a logistic regression. The stability and generalizability of the results was empirically demonstrated using a jack-knife validation, an internal bootstrap validation and an independent validation sample which completed the test batteries and the standardized driving test as part of a so-called traffic-psychological assessment which is compulsory in Austria in all cases, where the driver's licence has been withdrawn, e.g., when caught driving under the influence of alcohol. Moreover, the procedure allows calculating incremental validities which enable the assessment of the relative importance of the individual predictor variables. This contributes to the transparency of the results obtained with artificial neural networks. In summary it can be said that the results provide empirical evidence of the validity of the traffic-psychological tests batteries used in this study. The practical implications of the results for traffic-psychological assessment are described.
2012-01-01
Physical inactivity is one of the four leading risk factors for global mortality. Accurate measurement of physical activity (PA) and in particular by physical activity questionnaires (PAQs) remains a challenge. The aim of this paper is to provide an updated systematic review of the reliability and validity characteristics of existing and more recently developed PAQs and to quantitatively compare the performance between existing and newly developed PAQs. A literature search of electronic databases was performed for studies assessing reliability and validity data of PAQs using an objective criterion measurement of PA between January 1997 and December 2011. Articles meeting the inclusion criteria were screened and data were extracted to provide a systematic overview of measurement properties. Due to differences in reported outcomes and criterion methods a quantitative meta-analysis was not possible. In total, 31 studies testing 34 newly developed PAQs, and 65 studies examining 96 existing PAQs were included. Very few PAQs showed good results on both reliability and validity. Median reliability correlation coefficients were 0.62–0.71 for existing, and 0.74–0.76 for new PAQs. Median validity coefficients ranged from 0.30–0.39 for existing, and from 0.25–0.41 for new PAQs. Although the majority of PAQs appear to have acceptable reliability, the validity is moderate at best. Newly developed PAQs do not appear to perform substantially better than existing PAQs in terms of reliability and validity. Future PAQ studies should include measures of absolute validity and the error structure of the instrument. PMID:22938557
Chapman, Benjamin P; Weiss, Alexander; Duberstein, Paul R
2016-12-01
Statistical learning theory (SLT) is the statistical formulation of machine learning theory, a body of analytic methods common in "big data" problems. Regression-based SLT algorithms seek to maximize predictive accuracy for some outcome, given a large pool of potential predictors, without overfitting the sample. Research goals in psychology may sometimes call for high dimensional regression. One example is criterion-keyed scale construction, where a scale with maximal predictive validity must be built from a large item pool. Using this as a working example, we first introduce a core principle of SLT methods: minimization of expected prediction error (EPE). Minimizing EPE is fundamentally different than maximizing the within-sample likelihood, and hinges on building a predictive model of sufficient complexity to predict the outcome well, without undue complexity leading to overfitting. We describe how such models are built and refined via cross-validation. We then illustrate how 3 common SLT algorithms-supervised principal components, regularization, and boosting-can be used to construct a criterion-keyed scale predicting all-cause mortality, using a large personality item pool within a population cohort. Each algorithm illustrates a different approach to minimizing EPE. Finally, we consider broader applications of SLT predictive algorithms, both as supportive analytic tools for conventional methods, and as primary analytic tools in discovery phase research. We conclude that despite their differences from the classic null-hypothesis testing approach-or perhaps because of them-SLT methods may hold value as a statistically rigorous approach to exploratory regression. (PsycINFO Database Record