Search results for: D.R. Jensen

Items from 1 to 20 out of 27 results

article

Shift outliers in linear inference

D.R. Jensen, D.E. Ramirez

Journal of Multivariate Analysis > 2015 > 136 > Complete > 95-107

Shifts in responses typically are obscured from users, so that regression proceeds as if unshifted. At issue is the infusion of such shifts into classical analysis. On projecting outliers into the “Regressor” and “Error” spaces of a model, findings here are that shifts in responses may account for shifts in the OLS solutions, or for inflated residuals, or both. These in turn impact estimation, prediction,...

article

Leverage and subset efficiencies in regression

D.R. Jensen

Statistical Methodology > 2010 > 7 > 5 > 541-551

Leverages and coleverages comprise the matrix H in regression. These traditionally serve to gauge (i) the remoteness of regressors, (ii) the impact of responses on fitted values, (iii) the predictive efficiency of an observation Yi, (iv) powers of tests for outliers, and (v) limits on critical features of deletion diagnostics. This study goes beyond traditional usage in developing leverage efficiency...

article

Surrogate models in ill-conditioned systems

D.R. Jensen, D.E. Ramirez

Journal of Statistical Planning and Inference > 2010 > 140 > 7 > 2069-2077

Ridge versions of an ill-conditioned system are alleged to “act more like an orthogonal system” than the system itself. Alternatives, called surrogates and based on the conditioning of linear systems, are shown to yield smaller expected mean squares than OLS, and uniformly smaller residual sums of squares than ridge. Ridge and surrogate solutions are compared on several marques of orthogonality to...

article

Concentration reversals in ridge regression

D.R. Jensen, D.E. Ramirez

Statistics and Probability Letters > 2009 > 79 > 21 > 2237-2241

Ridge regression is often the method of choice for approaching ill-conditioned systems. A canonical form identifies regions in the parameter space where Ordinary Least Squares (OLS) is problematic. A curious but unrecognized property of ridge solutions emerges: Under spherical errors with or without moments, the relative concentrations of the canonical estimators reverse as the ridge scalar evolves,...

article

Gauss inequalities on ordered linear spaces

D.R. Jensen

Journal of Multivariate Analysis > 2006 > 97 > 4 > 985-998

Markov inequalities on ordered linear spaces are tightened through the α-unimodality of the corresponding measures. Modality indices are studied for various induced measures, including the singular values of a random matrix and the periodogram of a time series. These tools support a detailed study of linear inference and the ordering of random matrices, to include fixed and random designs and probability...

article

A Rotating Coil Apparatus With Sub-Micrometer Magnetic Center Measurement Stability

C.M. Spencer, S.D. Anderson, D.R. Jensen, Z.R. Wolf

IEEE Transactions on Applied Superconductivity > 2006 > 16 > 2 > 1334 - 1337

A rotating double coil apparatus has been designed and built so that the relative magnetic center change of a quadrupole is measured to an uncertainty smaller than 0.02 micrometers (=micron, mum) for a single measurement. Furthermore, repeated measurements over about an hour vary by less than 0.1 mum and by less than 1 mum for periods of 24 hrs or longer. Correlation analyses of long data runs show...

article

Matrix equivalence classes with applications

D.R. Jensen, S.S. Srinivasan

Linear Algebra and Its Applications > 2004 > 388 > Complete > 249-260

A definite matrix Σ is represented in terms of a semidefinite matrix Ω and a vector γ, such that (Ω,γ) may be recovered explicitly from Σ. Equivalence classes are generated over the cone of positive definite matrices, first on fixing Ω, then on fixing γ. These classes in turn associate naturally as scale parameters in ensembles of elliptical measures. Each ensemble is seen to admit a distinct linear...

article

Coexisting normal and triaxial superdeformed structures in ¹ ⁶ ⁵ Lu

G. Schönwaßer, N. Nenoff, H. Hübel, G.B. Hagemann, more

Nuclear Physics, Section A > 2004 > 735 > 3-4 > 393-424

High-spin states in ¹ ⁶ ⁵ Lu were populated in the ¹ ³ ⁹ La( ³ ⁰ Si,4n) reaction at a beam energy of 152 MeV and γ-ray coincidences were measured with the EUROBALL spectrometer array. Nine new rotational bands were discovered, known band structures were considerably extended and many inter-band transitions were found. Structures with normal deformation coexist...

article

Condition numbers and D-efficiency

D.R. Jensen

Statistics and Probability Letters > 2004 > 66 > 3 > 267-274

Suppose that experimental designs have comparable A-efficiencies for estimation, the choice among designs then depending on their comparative D-efficiencies. Using the theory of majorization, it is shown that designs having greater D-efficiencies are more ill-conditioned, using condition numbers based on the unitarily invariant matrix norms. Implications are drawn regarding ridge regression, Mauchly...

article

On the monotone convergence of vector means

D.R. Jensen

Journal of Multivariate Analysis > 2003 > 85 > 1 > 78-90

Consider a stochastic sequence {Z _n ;n=1,2,...}, and define P _n ( )=P(|Z _n |< ). Then the stochastic convergence Z _n ->0 is said to be monotone whenever the sequence P _n ( )↑1 monotonically in n for each >0. This mode of convergence is investigated here; it is seen to be stronger than convergence in quadratic mean; and scalar and vector sequences...

article

One- and two-phonon wobbling excitations in triaxial ¹ ⁶ ⁵ Lu

G. Schönwaßer, H. Hübel, G.B. Hagemann, P. Bednarczyk, more

Physics Letters B > 2003 > 552 > 1-2 > 9-16

High-spin states in ¹ ⁶ ⁵ Lu have been investigated by in-beam γ-ray coincidence spectroscopy using the EUROBALL spectrometer array. Two new excited rotational bands have been discovered with features similar to a previously known triaxial superdeformed band in that nucleus. Comparison of the decay pattern of these bands, in particular the unusually large E2 transition strength from...

article

First evidence for triaxial superdeformation in 161Lu and 162Lu

P. Bringel, H. Hbel, H. Amro, M. Axiotis, more

The European Physical Journal A > 2003 > 16 > 2 > 155-158

Abstract: High-spin states in 161Lu and 162Lu have been investigated using the GASP -ray spectrometer array. Excited states in these nuclei have been populated through the 100Mo(65Cu, xn) reaction at a beam energy of 260 MeV. Four presumably triaxial superdeformed bands, three in 162Lu and one in 161Lu, have been observed. This is the first evidence for triaxial superdeformation in the two isotopes.

article

Wobbling phonon excitations, coexisting with normal deformed structures in ¹ ⁶ ³ Lu

D.R. Jensen, G.B. Hagemann, I. Hamamoto, S.W. Ødegård, more

Nuclear Physics, Section A > 2002 > 703 > 1-2 > 3-44

Wobbling is a rotational mode unique to a triaxial body. The Lu-Hf isotopes with N~94 at high spin provide a possible region of nuclei with pronounced triaxiality. We have investigated ¹ ⁶ ³ Lu through the fusion-evaporation reaction ¹ ³ ⁹ La( ² ⁹ Si,5n) ¹ ⁶ ³ Lu with a beam energy of 152 MeV. Three excited bands decaying into the known,...

article

Count fluctuation analysis in the triaxial strongly deformed potential well of 163Lu

S.W. degrd, B. Herskind, T. Dssing, G.B. Hagemann, more

The European Physical Journal A > 2002 > 14 > 3 > 309-316

Abstract: High-spin properties of the triaxial strongly deformed potential well in 163Lu at excitation energies above resolvable bands have been investigated. Gated E-E spectra display clear ridges with moments of inertia corresponding to those observed for the discrete strongly deformed bands. A fluctuation analysis of the ridges yields a number of two-step paths of 40 and 20, when gating on triaxial...

article

First triaxial superdeformed band in 170Hf

A. Neuer, H. Hbel, G.B. Hagemann, S. Bhattacharya, more

The European Physical Journal A > 2002 > 15 > 4 > 439-441

Abstract: First evidence is presented for triaxial superdeformation in 170Hf. High-spin states in this nucleus have been investigated in a -ray coincidence measurement using the EUROBALL spectrometer array. A new band was discovered which has moments of inertia that are very similar to the ones of triaxial superdeformed bands in neighbouring Hf and Lu nuclei. The intensities with which these bands...

article

Properties of selected subset diagnostics in regression

D.R. Jensen

Statistics and Probability Letters > 2001 > 51 > 4 > 377-388

Anomalies are cited in the use of subset regression diagnostics. Two leverage diagnostics are unified through canonical leverages. Other diagnostics relate one-to-one with the R-Fisher statistic, supporting exact but equivalent tests at level α. Three distance diagnostics exhibit ad hoc scalings; their distributions are characterized and ordering properties noted; one is studied further through simulation;...

article

Search for the wobbling mode built on triaxial super deformation

S.W. Ødegård, G.B. Hagemann, M. Bergström, B. Herskind, more

Nuclear Physics, Section A > 2001 > 682 > 1-4 > 427-432

article

Surf generated aerosols

D.R. Jensen, S.G. Gathman, W. Hooper

Journal of Aerosol Science > 2000 > 31 > Supplement 1 > 538-539

article

Marine aerosol particles and infrared transmission

C.R. Zeisse, S.G. Gathman, D.R. Jensen, K.M. Littfin, more

Journal of Aerosol Science > 1999 > 30 > Supplement 1 > S13-S14

article

Marine aerosol and midwave infrared transmission

B.D. Nener, T. Ridsdill-Smith, C.R. Zeisse, S.G. Gathman, more

Journal of Aerosol Science > 1999 > 30 > Supplement 1 > S193-S194

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Search results for: D.R. Jensen

Shift outliers in linear inference

Leverage and subset efficiencies in regression

Surrogate models in ill-conditioned systems

Concentration reversals in ridge regression

Gauss inequalities on ordered linear spaces

A Rotating Coil Apparatus With Sub-Micrometer Magnetic Center Measurement Stability

Matrix equivalence classes with applications

Coexisting normal and triaxial superdeformed structures in ¹ ⁶ ⁵ Lu

Condition numbers and D-efficiency

On the monotone convergence of vector means

One- and two-phonon wobbling excitations in triaxial ¹ ⁶ ⁵ Lu

First evidence for triaxial superdeformation in 161Lu and 162Lu

Wobbling phonon excitations, coexisting with normal deformed structures in ¹ ⁶ ³ Lu

Count fluctuation analysis in the triaxial strongly deformed potential well of 163Lu

First triaxial superdeformed band in 170Hf

Properties of selected subset diagnostics in regression

Search for the wobbling mode built on triaxial super deformation

Surf generated aerosols

Marine aerosol particles and infrared transmission

Marine aerosol and midwave infrared transmission

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