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167 results on '"Kirchner, P. D."'

1. Mining Documentation to Extract Hyperparameter Schemas

Author

Baudart, Guillaume, Kirchner, Peter D., Hirzel, Martin, and Kate, Kiran

Subjects
Computer Science - Machine Learning, Computer Science - Databases, Statistics - Machine Learning
Abstract

AI automation tools need machine-readable hyperparameter schemas to define their search spaces. At the same time, AI libraries often come with good human-readable documentation. While such documentation contains most of the necessary information, it is unfortunately not ready to consume by tools. This paper describes how to automatically mine Python docstrings in AI libraries to extract JSON Schemas for their hyperparameters. We evaluate our approach on 119 transformers and estimators from three different libraries and find that it is effective at extracting machine-readable schemas. Our vision is to reduce the burden to manually create and maintain such schemas for AI automation tools and broaden the reach of automation to larger libraries and richer schemas.

Published
2020

6. A SERIES OF FIVE PATIENTS WITH FOVEAL HYPOPLASIA DEMONSTRATING GOOD VISUAL ACUITY.

Author

Kirchner, Ian D., Waldman, Corey W., and Sunness, Janet S.

Abstract

Background/Purpose: Foveal hypoplasia is associated with low vision in a variety of conditions. We report and show imaging studies for a series of five patients with foveal hypoplasia who had visual acuity ranging from 20/25 to 20/60. Methods: Observational case series. Patients: This series includes five patients aged 5 to 18 years who presented to the Greater Baltimore Medical Center, Hoover Low Vision Clinic. All patients showed a partial or complete absence of the fovea in both eyes on examination. Results: Eight eyes exhibited absence of foveal depression on spectral domain optical coherence tomography (Cirrus high-definition OCT; Carl Zeiss Meditec). Four eyes exhibited Grade 3 foveal hypoplasia, two eyes exhibited Grade 4 foveal hypoplasia, and two eyes exhibited Grade 1 foveal hypoplasia. For two eyes (one patient), the optical coherence tomography was no longer available for grading, but was interpreted as foveal hypoplasia in both eyes in the chart. Visual acuities ranged from 20/25 to 20/60. Only two of five patients showed signs of albinism. Conclusion: Despite the presence of foveal hypoplasia, patients can retain a high level of visual acuity, which suggests that a foveal depression is not essential for the development of good visual acuity. [ABSTRACT FROM AUTHOR]

Published
2019
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7. Structure and recombination in InGaAs/GaAs heterostructures.

Author

Fitzgerald, E. A., Ast, D. G., Kirchner, P. D., Pettit, G. D., and Woodall, J. M.

Subjects
INDIUM compounds, HETEROSTRUCTURES, GALLIUM arsenide
Abstract

Focuses on a study that investigated the structure and recombination in indium gallium arsenide/gallium arsenide heterostructures. Methodology; Results and discussion; Conclusions.

Published
1988
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9. Arsenic cluster dynamics in doped GaAs.

Author

Melloch, M. R., Otsuka, N., Mahalingam, K., Chang, C. L., Woodall, J. M., Pettit, G. D., Kirchner, P. D., Cardone, F., Warren, A. C., and Nolte, D. D.

Subjects
ARSENIC, ELECTRON precipitation, GALLIUM arsenide, SEMICONDUCTOR doping, MOLECULAR beam epitaxy
Abstract

Presents a study which investigated the formation of arsenic precipitates in doped gallium arsenide (GaAs) structures grown by molecular beam epitaxy. Technique for the GaAs epilayer growth; Experimental procedures used; Results of the study.

Published
1992
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10. Mechanism and conditions for anomalous strain relaxation in graded thin films and superlattices.

Author

LeGoues, F. K., Meyerson, B. S., Morar, J. F., and Kirchner, P. D.

Subjects
ELECTRONIC structure, THIN films, ALLOYS, SEMICONDUCTORS
Abstract

Presents a study which investigated the different modes of strain relaxation associated with the compositional grading of SiGe/Si(100) and GaInAs/GaAs semiconductor thin films and alloys. Details on the formation of dislocations in the thin films; Effects of compositional grading on dislocations; Analysis of the dislocations.

Published
1992
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11. Temperature dependence of the photoreflectance of a strained layer (001) In0.21Ga0.79As/GaAs single quantum well.

Author

Huang, Y. S., Qiang, H., Pollak, Fred H., Pettit, G. D., Kirchner, P. D., Woodall, J. M., Stragier, Hans, and Sorensen, Larry B.

Subjects
QUANTUM wells, SPECTRUM analysis, GALLIUM arsenide
Abstract

Presents information on the measurement of the photoreflectance spectra of a strained layer (001) In[sub0.21]Ga[sub0.79]As/gallium arsenide single quantum well (SQW). Preparation of the SQW; Line shape considerations.

Published
1991
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12. Structure and chemical composition of water-grown oxides of GaAs.

Author

Liliental-Weber, Z., Wilmsen, C. W., Geib, K. M., Kirchner, P. D., Baker, J. M., and Woodall, J. M.

Subjects
OXIDES, GALLIUM arsenide
Abstract

Presents a study that examined the characteristics of oxides grown on gallium arsenide by photowashing and stagnant water processes. Analysis of the physical structure of the oxides; Determination of the chemical composition of the oxides; Evaluation of the crystallinity of the oxides.

Published
1990

13. Nucleation mechanisms and the elimination of misfit dislocations at mismatched interfaces by reduction in growth area.

Author

Fitzgerald, E. A., Watson, G. P., Proano, R. E., Ast, D. G., Kirchner, P. D., Pettit, G. D., and Woodall, J. M.

Subjects
INTERFACES (Physical sciences), DISLOCATIONS in crystals, EPITAXY, GALLIUM arsenide
Abstract

Investigates the effect of growth area on interface dislocation density in strained-layer epitaxy. Interface structure of In[sub0.05]Ga[sub0.95]As/gallium arsenide heterostrcutures grown on patterned substrates containing many mesas, varying in lateral dimensions and geometry; Nucleation mechanisms active for different epilayer thicknesses; Interface-dislocation densities near zero.

Published
1989
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15. Effects of N2, O2, and H2O on GaAs passivated by photowashing or coating with Na2S·9H2O.

Author

Wilmsen, C. W., Kirchner, P. D., and Woodall, J. M.

Subjects
*GALLIUM arsenide, *WATER vapor transport, *OXYGEN, *PHOTOLUMINESCENCE
Abstract

Discusses a study that investigated the effects of nitrogen[sub2], oxygen[sub2] and water on gallium arsenide passivated by photowashing. Importance of the presence of water vapor and oxygen in obtaining large photoluminescence signal; Use of measuring laser light in activation.

Published
1988
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16. Optimizing Defocus to Increase Efficiency in Concentrator Photovoltaic Modules

Author

Wacaser, Brent A., Alyahya, Abdulaziz, Kirchner, Peter D., Alowais, Abdullah, Martin, Yves, Halawani, Mohammad, Sandstrom, Robert L., Eugenio, Nunilo N., Aljuwaied, Mazzen, Badahdah, Alhassan, VanKessel, Theodore G., and Khonkar, Hussam

Abstract

We describe a process for increasing power efficiency of concentrator photovoltaic (PV) systems by optimizing the lens-to-cell spacing. We find that there is an optimum defocus position with improved power output and reduced sensitivity to pointing errors, which, in combination, can result in a more than 10% enhancement. The improvement can be realized by minor changes to module cases which should not require changes to other manufacturing, installation, or component costs. In fact, optimizing the defocus position allows for lower costs per unit power due to increased power and relaxed system tolerances. This paper focuses on detailed data illuminating the behavior of ultrahigh concentration PV modules, while one can look forward to optimizing defocus through sufficiently detailed simulation; at present, we find that an empirical determination of optimum defocus is necessary. The data reveal that even without design parameters changing, supply chain changes can have a significant impact on the optimum defocus; data from five different module configurations with components from different manufacturing lots are presented. These different configurations serve to illustrate the consequences of component changes and the importance of verifying the optimum defocus. A detailed discussion of the effects that are important to determine the optimum defocus and which underlie these differences is included.

Published
2015
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17. High-Concentration Photovoltaics—Effect of Inhomogeneous Spectral Irradiation

Author

Martin, Yves, Kirchner, Peter D., van Kessel, Theodore, Wacaser, Brent, Sandstrom, Robert, Patel, Dhiren, Kim, Ben, Badahdah, Alhassan, Khonkar, Hussam, Leutz, Ralf, Fu, Ling, and Annen, Hans Philipp

Abstract

At high solar concentration, subtle optical and electrical effects in combination can have a substantial impact on photovoltaic power (PV) generation. We have identified such an effect through its clear signature: a “ripple” in the output current with respect to the pointing angle of the concentrated PV (CPV) system to sun direction. At small angular misalignment, this effect can lower cell current by as much as 15% at 1600x concentration in full sun. At medium concentration between 500 and 1000x, while not as clearly visible in single cells, the effect also reduces output by a smaller amount. The disappearance of the “ripple” signature at low concentrations below 300x indicates that the effect is not a linear effect, such as a light loss. We attribute the pronounced angular sensitivity of power output at high concentrations to a combination of inhomogeneous spectral irradiation incident on the multijunction solar cell and of the impact of the finite lateral resistance of the cell.

Published
2015
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22. Faltaet al. reply

Author

Falta, J., primary, Tromp, R. M., additional, Copel, M., additional, Pettit, G. D., additional, and Kirchner, P. D., additional

Published
1993
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