MARIT : the design, implementation and trajectory generation with NTG for small UAVs.

This dissertation is about building a Multiple Air Robotics Indoor Testbed (MARIT) for the purpose of developing and validating new methodologies for collaboration and cooperation between heterogeneous Unmanned Air Vehicles (UAVs) as well as expandable to air-and-ground vehicle teams. It introduces a mathematical model for simulation and control of quadrotor Small UAVs (SUAVs). The model is subsequently applied to design an autonomous quadrotor control and tracking system. The dynamics model of quadrotor SUAV is used in several control designs. Each control design is simulated and compared. Based on the comparison, the superior control design is use for experimental flights. Two methods are used to evaluate the control and collect real-time data. The Nonlinear Trajectory Generation (NTG) software package is used to provide optimal trajectories for the SUAVs in MARIT. The dynamics model of the quadrotor is programmed in NTG and various obstacle avoidance scenarios are modeled to establish a platform for optimal trajectory generation for SUAVs. To challenge the capability of NTG for real-time trajectory generation, random obstacles and disturbances are simulated. Various flight simulations validate this trajectory tracking approach

Microstructure-specific Hardening of Ferritic-Martensitic Steels pre and post 15 dpa Neutron Irradiation at 330°C: A Dislocation Dynamics Study

In this work, we used Dislocation Dynamics (DD) simulations to investigate the role of the hierarchical defects microstructure of ferritic-martensitic steel Eurofer97 in determining its hardening behavior. A Representative Volume Element (RVE) for DD simulation is identified based on the typical martensitic lath size. Material properties for DD simulations in b.c.c Eurofer97 are determined, including the dislocation mobility parameters. The dependence of material parameters on temperature is fitted to experimental yield strength measurements carried out at room temperature and 330 °C, respectively. Voids and precipitates observed in the microstructure, such as M23C6 and Tantalum-rich MX, are considered in our DD simulations as inclusions with realistic size distribution and volume density, while 〈1 1 1〉 -and 〈1 0 0〉 -type irradiation loops are included directly in the DD simulations. The lath structure, together with its typical precipitates arrangement and the different crystallographic orientation of the martensitic blocks can also be captured in the simulations. DD simulations are used to extract microstructure-specific hardening parameters, which can be used to simulate the properties of Eurofer97 at the engineering scale

Donnan Potential across the Outer Membrane of Gram-Negative Bacteria and Its Effect on the Permeability of Antibiotics

The cell envelope structure of Gram-negative bacteria is unique, composed of two lipid bilayer membranes and an aqueous periplasmic space sandwiched in between. The outer membrane constitutes an extra barrier to limit the exchange of molecules between the cells and the exterior environment. Donnan potential is a membrane potential across the outer membrane, resulted from the selective permeability of the membrane, which plays a pivotal role in the permeability of many antibiotics. In this review, we discussed factors that affect the intensity of the Donnan potential, including the osmotic strength and pH of the external media, the osmoregulated periplasmic glucans trapped in the periplasmic space, and the displacement of cell surface charges. The focus of our discussion is the impact of Donnan potential on the cellular permeability of selected antibiotics including fluoroquinolones, tetracyclines, β-lactams, and trimethoprim

Transmembrane routes of cationic liposome-mediated gene delivery using human throat epidermis cancer cells

For studying the mechanism of cationic liposome-mediated transmembrane routes for gene delivery, various inhibitors of endocytosis were used to treat human throat epidermis cancer cells, Hep-2, before transfection with Lipofectamine 2000/pGFP-N2 or Lipofectamine 2000/pGL3. To eliminate the effect of inhibitor toxicity on transfection, the RLU/survival rate was used to represent the transfection efficiency. Chlorpromazine and wortmannin, clathrin inhibitors, decreased transfection efficiency by 44 % (100 μM) and 31 % (100 nM), respectively. At the same time, genistein, a caveolin inhibitor, decreased it by 30 % (200 μM). Thus combined transmembrane routes through the clathrin and caveolae-mediated pathways were major mechanisms of cell uptake for the cationic liposome-mediated gene delivery. After entering the cells, microtubules played an important role on gene delivery as vinblastine, a microtubulin inhibitor, could reduce transfection efficiency by 41 % (200 nM)

DAGC: Data-Volume-Aware Adaptive Sparsification Gradient Compression for Distributed Machine Learning in Mobile Computing

Distributed machine learning (DML) in mobile environments faces significant communication bottlenecks. Gradient compression has emerged as an effective solution to this issue, offering substantial benefits in environments with limited bandwidth and metered data. Yet, they encounter severe performance drop in non-IID environments due to a one-size-fits-all compression approach, which does not account for the varying data volumes across workers. Assigning varying compression ratios to workers with distinct data distributions and volumes is thus a promising solution. This study introduces an analysis of distributed SGD with non-uniform compression, which reveals that the convergence rate (indicative of the iterations needed to achieve a certain accuracy) is influenced by compression ratios applied to workers with differing volumes. Accordingly, we frame relative compression ratio assignment as an $n$-variables chi-square nonlinear optimization problem, constrained by a fixed and limited communication budget. We propose DAGC-R, which assigns the worker handling larger data volumes the conservative compression. Recognizing the computational limitations of mobile devices, we DAGC-A, which are computationally less demanding and enhances the robustness of the absolute gradient compressor in non-IID scenarios. Our experiments confirm that both the DAGC-A and DAGC-R can achieve better performance when dealing with highly imbalanced data volume distribution and restricted communication

Health poverty alleviation in China from the perspective of historical institutionalism: policy changes and driving factors

Health poverty alleviation is an effective tool for improving the living quality and developmental conditions of impoverished populations. Since 1978, China has been actively implementing health poverty alleviation projects, resulting in a more robust rural healthcare service network and increased convenience for the local population to access medical treatment. However, it is crucial to acknowledge that China still faces a complex situation with the simultaneous existence of multiple disease threats and the interweaving of various health influencing factors. Ongoing risks of emerging infectious diseases persist, and some previously controlled or eliminated infectious diseases are at risk of resurgence. The incidence of chronic diseases is on the rise and exhibits a trend toward affecting younger populations. Therefore, examining the successful experiences of China's health poverty alleviation over the past 40 years becomes a critically important issue. The study focuses on China's health poverty alleviation policies, employing historical institutionalism as a theoretical perspective to analyze the historical changes and evolutionary logic of health poverty alleviation policies. A historical institutionalist analytical framework for health poverty alleviation policies is constructed. The research findings reveal that China's health poverty alleviation policy has undergone three distinct periods since 1978: the initial phase (1978–2000), the exploratory phase (2000–2012), and the stable development phase (2013–present). At the macro level, the political, economic, and social contexts of different periods have influenced the evolution of health poverty alleviation policies. On the meso level, coordination effects and adaptive expectations have had an impact on China's health poverty alleviation policy. At the micro level, various actors, including the central government, local governments at different levels, social forces, and impoverished communities, interact during the evolution of health poverty alleviation policies. This paper summarizes the theoretical aspects of China's health poverty alleviation policy experience. The research conclusions, viewed through the lens of historical institutionalism, offer practical insights into the evolution of government policies. This provides directional guidance for enhancing health poverty alleviation projects

Monodisperse Fiber-like Micelles of Controlled Length and Composition with an Oligo(<i>p</i>-phenylenevinylene) Core via “Living” Crystallization-Driven Self-Assembly

We report the preparation of a series of fiber-like micelles of narrow length distribution with an oligo­(<i>p</i>-phenylenevinylene) (OPV)-core and a poly­(<i>N</i>-isopropylacrylamide) (PNIPAM) corona via two different crystallization-driven self-assembly (CDSA) strategies. The average length <i>L</i>_n of these micelles can be varied up to 870 nm by varying the temperature in self-seeding experiments. In addition, seeded growth was employed not only to prepare uniform micelles of controlled length, but also to form fiber-like A-B-A triblock comicelles with an OPV-core