An investigation of small-scale motions and the forecasting of wind profiles over short periods of time at Cape Kennedy, Florida

Small scale motions and numerical wind profiles forecasting for short periods at Cape Kenned

A comparative analysis of rawinsonde and NIMBUS 6 and TIROS N satellite profile data

Comparisons are made between rawinsonde and satellite profiles in seven areas for a wide range of surface and weather conditions. Variables considered include temperature, dewpoint temperature, thickness, precipitable water, lapse rate of temperature, stability, geopotential height, mixing ratio, wind direction, wind speed, and kinematic parameters, including vorticity and the advection of vorticity and temperature. In addition, comparisons are made in the form of cross sections and synoptic fields for selected variables. Sounding data from the NIMBUS 6 and TIROS N satellites were used. Geostrophic wind computed from smoothed geopotential heights provided large scale flow patterns that agreed well with the rawinsonde wind fields. Surface wind patterns as well as magnitudes computed by use of the log law to extrapolate wind to a height of 10 m agreed with observations. Results of this study demonstrate rather conclusively that satellite profile data can be used to determine characteristics of large scale systems but that small scale features, such as frontal zones, cannot yet be resolved

Bayesian Image Reconstruction using Deep Generative Models

Machine learning models are commonly trained end-to-end and in a supervised setting, using paired (input, output) data. Examples include recent super-resolution methods that train on pairs of (low-resolution, high-resolution) images. However, these end-to-end approaches require re-training every time there is a distribution shift in the inputs (e.g., night images vs daylight) or relevant latent variables (e.g., camera blur or hand motion). In this work, we leverage state-of-the-art (SOTA) generative models (here StyleGAN2) for building powerful image priors, which enable application of Bayes' theorem for many downstream reconstruction tasks. Our method, Bayesian Reconstruction through Generative Models (BRGM), uses a single pre-trained generator model to solve different image restoration tasks, i.e., super-resolution and in-painting, by combining it with different forward corruption models. We keep the weights of the generator model fixed, and reconstruct the image by estimating the Bayesian maximum a-posteriori (MAP) estimate over the input latent vector that generated the reconstructed image. We further use variational inference to approximate the posterior distribution over the latent vectors, from which we sample multiple solutions. We demonstrate BRGM on three large and diverse datasets: (i) 60,000 images from the Flick Faces High Quality dataset (ii) 240,000 chest X-rays from MIMIC III and (iii) a combined collection of 5 brain MRI datasets with 7,329 scans. Across all three datasets and without any dataset-specific hyperparameter tuning, our simple approach yields performance competitive with current task-specific state-of-the-art methods on super-resolution and in-painting, while being more generalisable and without requiring any training. Our source code and pre-trained models are available online: https://razvanmarinescu.github.io/brgm/.Comment: 27 pages, 17 figures, 5 table

Interminiband Rabi oscillations in biased semiconductor superlattices

Carrier dynamics at energy level anticrossings in biased semiconductor superlattices, was studied in the time domain by solving the time-dependent Schroedinger equation. The resonant nature of interminiband Rabi oscillations has been explicitly demonstrated to arise from interference of intrawell and Bloch oscillations. We also report a simulation of direct Rabi oscillations across three minibands, in the high field regime, due to interaction between three strongly coupled minibands.Comment: 13 pages, 16 figure

AN ANALYSIS OF AIR FORCE CONTRACT MANAGEMENT PERSONNEL COMPETENCY AND INTERNAL PROCESSES USING THE NATIONAL CONTRACT MANAGEMENT ASSOCIATION'S THIRD-PARTY ACCREDITED COMPETENCY STANDARD

For the last two decades, the Government Accountability Office (GAO) has listed the Department of Defense’s (DoD) contract management practices as a high-risk area. Additionally, in 2019, contract management oversight appeared as one of the DoD Inspector General’s (IG) top management challenges. DoD continues to review processes, training, and organizational assessments for effectiveness. However, the contracting workforce needs competency in both the buyer and seller roles from the contract management life cycle to be truly effective. The National Contract Management Association (NCMA) Contract Management Body of Knowledge (CMBOK) Contract Management Standard (CMS) was chosen as the competency framework for our research, as it fulfills this need. The purpose of this research is to conduct an analysis of DoD IG–reported contract management deficiencies from DoD IG inspections for the Air Force and align these deficiencies with the third-party accredited NCMA CMS competency framework. Additionally, since the Air Force contracting organizations use self-inspections as part of internal controls to prepare for DoD IG inspections, this research provides a comparative analysis between the CMS and the Air Force Contracting Self-Inspection Checklist. Finally, the research provides recommendations for training opportunities and improving the checklist, which clearly align with two of the three parts of auditability theory.Civilian, Department of the Air ForceCivilian, Department of the Air ForceCivilian, Department of the Air ForceApproved for public release. distribution is unlimite

Stability and electronic structure of the complex K2_2PtCl6_6 structure-type hydrides

The stability and bonding of the ternary complex K$_2$PtCl$_6$ structure hydrides is discussed using first principles density functional calculations. The cohesion is dominated by ionic contributions, but ligand field effects are important, and are responsible for the 18-electron rule. Similarities to oxides are discussed in terms of the electronic structure. However, phonon calculations for Sr$_2$RuH$_6$ also show differences, particularly in the polarizability of the RuH$_6$ octahedra. Nevertheless, the yet to be made compounds Pb$_2$RuH$_6$ and Be$_2$FeH$_6$ are possible ferroelectrics. The electronic structure and magnetic properties of the decomposition product, FeBe$_2$ are reported. Implications of the results for H storage are discussed