The Fourth District Police Station Plan

The purpose of this plan is to identify potential police station sites and create design guidelines for the new police station for the Prince William County Police Department

Non-Destructive Viscoelasticity Microscopy: A Spectroscopic Approach using Dual Brillouin/Raman Scattering Processes

The tremendous progress in life sciences and medicine has been greatly facilitated by the development of new imaging modalities. The elastic properties of molecules, subcellular and cellular structures play a crucial role in many areas of biology and medicine. Tissue elasticity has recently been recognized as a critical regulator of cell behavior, with clear roles in embryogenesis, tissue morphogenesis and stem cell differentiation, as well as contributing to pathologies such as tumor progression, coronary artery disease and tissue scarring. This dissertation is focused on developing a novel instrumentation to image viscoelastic properties of cells and tissues using Brillouin microspectroscopy. Following design, construction and optimizations that maximize the signal quality, we obtained the highest resolution Brillouin imaging system in a confocal backscattering arrangement suitable for bio-imaging applications. Furthermore, a powerful combination of Brillouin and Raman spectroscopies has yielded a confocal microscope capable of performing simultaneous mechanical and chemical imaging in a non-invasive and noncontact manner. The novel instrument was optimized and validated for several biomedical applications. For example, we demonstrated that Brillouin spectroscopy is capable of performing in-vivo measurements of the mechanical properties of artificial biocompatible materials such as photocrosslinkable gelatin methacrylate (GelMA). With the assistance of animal models of human congenital muscular dystrophies, we show that Brillouin spectroscopy can serve as a unique diagnosis tool, which can detect differences in muscle elasticity even between very similar muscular dystrophy genotypes. We have also demonstrated that Brillouin spectroscopy is an invaluable approach in developmental biology since it is capable of making non-destructive imaging of an embryo's elasticity during its development process, which is crucial to understand the formation of many essential organs such as bone and brain. In summary, we have developed a novel instrument for biomedical imaging sensing, which is compatible with other microscopic imaging modalities and is specific to local elasticity. Numerous applications of this new technology have been explored, and the instrument’s performance was validated for several systems

Confidence-aware Non-repetitive Multimodal Transformers for TextCaps

When describing an image, reading text in the visual scene is crucial to understand the key information. Recent work explores the TextCaps task, i.e. image captioning with reading Optical Character Recognition (OCR) tokens, which requires models to read text and cover them in generated captions. Existing approaches fail to generate accurate descriptions because of their (1) poor reading ability; (2) inability to choose the crucial words among all extracted OCR tokens; (3) repetition of words in predicted captions. To this end, we propose a Confidence-aware Non-repetitive Multimodal Transformers (CNMT) to tackle the above challenges. Our CNMT consists of a reading, a reasoning and a generation modules, in which Reading Module employs better OCR systems to enhance text reading ability and a confidence embedding to select the most noteworthy tokens. To address the issue of word redundancy in captions, our Generation Module includes a repetition mask to avoid predicting repeated word in captions. Our model outperforms state-of-the-art models on TextCaps dataset, improving from 81.0 to 93.0 in CIDEr. Our source code is publicly available.Comment: 9 pages; Accepted by AAAI 202

Light Scattering Problem and its Application in Atmospheric Science

The light scattering problem and its application in atmospheric science is studied in this thesis. In the first part of this thesis, light scattering theory of single irregular particles is investigated. We first introduce the basic concepts of the light scattering problem. T-matrix ansatz, as well as the null-field technique, are introduced in the following sections. Three geometries, including sphere, cylinder and hexagonal column, are defined subsequently. Corresponding light scattering properties (i.e., T-matrix and Mueller Matrix) of those models with arbitrary sizes are simulated via the T-matrix method. In order to improve the efficiency for the algorithms of single-light scattering, we present a user-friendly database software package of the single-scattering properties of individual dust-like aerosol particles. The second part of this thesis describes this database in detail. Its application to radiative transfer calculations in a spectral region from ultraviolet (UV) to far-infrared (far-IR) is introduced as well. To expand the degree of morphological freedom of the commonly used spheroidal and spherical models, triaxial ellipsoids were assumed to be the overall shape of dust-like aerosol particles. The software package allows for the derivation of the bulk optical properties for a given distribution of particle microphysical parameters (i.e., refractive index, size parameter and two aspect ratios). The array-oriented single-scattering property data sets are stored in the NetCDF format. The third part of this thesis examines the applicability of the tri-axial ellipsoidal dust model. In this part, the newly built database is equipped in the study. The precomputed optical properties of tri-axial models are imported to a polarized addingdoubling radiative transfer (RT) model. The radiative transfer property of a well-defined atmosphere layer is consequently simulated. Furthermore, several trial retrieval procedures are taken based on a combination of intensity and polarization in the results of RT simulation. The retrieval results show a high precision and indicate a further application in realistic studies