Radio Sensor for Monitoring of UMTS Mobile Terminals

Relatively simple and low-cost radio sensor for monitoring of 3rd generation (3G) UMTS mobile terminals (i.e., phones) has been designed and practically tested. The main purpose of this sensor is to serve as an extending module that can be installed into systems used for monitoring of standard 2nd generation (2G) GSM and DCS mobile phones in highly guarded buildings and areas. Since the transmitted powers of UMTS mobile terminals can be very low in relation to GSM and DCS specifications, the new UMTS sensor is based on a highly sensitive receiver and additional signal processing. The radio sensor was practically tested in several scenarios representing worst-case mobile terminal - base station relations. The measured detection ranges attain values from approx. 11 m inside of rooms to more than 30 m in corridors, which seems to be sufficient for the expected application. Results of all performed tests correspond fairly well with the presented theoretical descriptions. An extended version of the radio sensor can be used for monitoring of mobile terminals of all existing voice or data formats

ROBUSTNESS OF MACHINE LEARNING FOR POWER SYSTEMS

The applications of machine learning are broad and useful for a variety of industry and military objectives, but are the current methods robust? Robustness requires more than accuracy in ideal conditions; it means the system is resistant to perturbations in the data, both from natural and adversarial causes. This research aims to analyze the robustness of neural networks used for power-grid fault classifications. We focus on data generated from simulations of the classical 9-bus model; however, these methods and results can be extended to more complex microgrids, such as those found on naval ships, submarines, and bases. First, we measure the effects of random and adversarial noise on the testing data and compare three network types. Then we test different structures by varying the number of nodes and layers. Finally, we test whether adding noise to the training data can improve robustness. Before machine learning methods are adopted on submarines, we must first understand their weaknesses and potential for error. This research provides the foundation for how to test robustness, where neural networks are at risk from random or adversarial noise, and how to modify networks to improve their robustness.Outstanding ThesisEnsign, United States NavyApproved for public release. Distribution is unlimited

Mathematical Modelling of the Electrical Discharge Mechanical Alloying Process

AbstractIn the paper, a comprehensive study of the electro-discharge mechanical alloying with using brush electrode is presented. This kind of a novel method is denoted as BEDMA (Brush Electro-Discharge Mechanical Alloying) and it combines features of electrical discharge machining with thermo-mechanical treatment. Electrode is being made of material which is to be alloyed on the part surface. A mathematical modelling of the thermal processes and mechanical action during the interaction of a single filament on the machined surface have been developed and used to estimation of the material transfer rate

Formation of the Aerosol of Space Origin in Earth's Atmosphere

The problem of formation of the aerosol of space origin in Earth s atmosphere is examined. Meteoroids of the mass range of 10-18-10-8 g are considered as a source of its origin. The lower bound of the mass range is chosen according to the data presented in literature, the upper bound is determined in accordance with the theory of Whipple s micrometeorites. Basing on the classical equations of deceleration and heating for small meteor bodies we have determined the maximal temperatures of the particles, and altitudes at which they reach critically low velocities, which can be called as velocities of stopping . As a condition for the transformation of a space particle into an aerosol one we have used the condition of non-reaching melting temperature of the meteoroid. The simplified equation of deceleration without earth gravity and barometric formula for the atmosphere density are used. In the equation of heat balance the energy loss for heating is neglected. The analytical solution of the simplified equations is used for the analysis

Electro-Thermal Effects of Power Transistors on Converter Performance

In this work, a comparative study of the electrical and thermal performance of a silicon carbide (SiC) MOSFET and a silicon (Si) IGBT power transistor, operating in a DC/DC boost converter, is presented. Behavioral models of Powerex Inc. switching transistors were developed in Synopsys SaberRD and used to predict the converter electrical efficiency; ANSYS Icepak modeling software was used for thermal simulations to identify potential hot spots. This work provides an overall, electro-thermal analysis of both transistor types with respect to switching frequency in the boost converter circuit. Optimal switching frequencies for each device at a given current are observed, and thermal performance of the SiC MOSFET is quantified with comparable or greater electrical efficiency to the Si IGBT. Our SiC MOSFET temperature measurements further validated published mathematical expressions, which help, in this study, to identify the best operating frequency with respect to electrical and thermal performance. Performance analysis and design considerations from the DC/DC converter were then applied to design a 2kW, high power density, gallium nitride (GaN) based, modular multilevel converter (M2C). Half-bridge submodules for a single-phase, low voltage, high power density inverter (450 VDC, 2 kW, < 40in3 volume) were designed, constructed, and analyzed. This power density is predicted through the utilization of the EPC2014C gallium nitride (GaN) transistor into the half-bridge submodules of the M2C. These submodules are configured in series and parallel, with a switching frequency of 24 kHz, to achieve the voltage and current requirements. Each arm of the M2C was designed onto a double-sided, 6-layer, printed circuit board (PCB). The design and fabrications for these power boards are discussed as well. The design, fabrication, and analysis of all three power conversion circuits presented here also include similar analysis for their gate drive circuits

The Example of State Forestry Information System (SFIS) Data Application to Prognosis of Changes in Pine Forests

W pracy pokazano zastosowanie danych z podsystemu «Las» Systemu Informatycznego Lasów Państwowych (SILP) w Polsce do prognozowania zmian lasów sosnowych. Zaprezentowano specjalnie opracowany blok «GAP TAKSACYJNY» modelu komputerowego pozwalający na automatyczne wczytywanie uśrednionych danych taksacyjnych dla wydzieleń leśnych i przeprowadzenie prognoz na przykładzie nadleśnictwa Tuczno z Wielkopolski.The paper shows the application of data from the subsystem «Forest» State Forestry Information System (SILP) in Poland for forecasting changes in pine forests. There was presented a specially designed block «GAP TAKSACYJNY» of computer model that allows the automatic loading of sub-compartment forests data and carrying out prognosis on the example of forest district Tuczno in Wielkopolska

Phenolic and Flavonoid Content in Hericium Erinaceus, Ganoderma Lucidum and Agrocybe Aegerita under Selenium Addition

The phenolic and flavonoid contents and composition and the antioxidant ability in Hericium erinaceus, Ganoderma lucidum, and Agrocybe aegerita under selenium (Se) addition to growth medium were studied. The contents of total Se in fruiting bodies of controls (0 mM of Se) were 4.58 (A. aegerita), 8.53 (G. lucidum), and 14.29 (H. erinaceus) mg kg–1 dry weight (DW), and was significantly increased by Se enrichment of substrate. The total phenolics in fruiting bodies of controls of H. erinaceus, G. lucidum, and A. aegerita were significantly lower (17.10, 28.11, and 16.05 mg of gallic acid equivalent (GAE)/g of extract, respectively) than for Se-rich mushrooms (26.29, 40.29, and 20.07 mg GAE/g of extract, respectively). Total flavonoid content for H. erinaceus, G. lucidum, and A. aegerita increased after Se supplementation from 368.6 to 445.6, 469.9 to 627.7, and 318.1 to 393.9 μg g–1 of extract, respectively. The results show that the mushrooms have superior antioxidant properties after Se addition, because the scavenging ability on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals was improved

Effect of electrolyte temperature on the thickness of anodic aluminium oxide (AAO) layer

Effect of electrolyte temperature on the thickness of resulting oxide layer has been studied. Unlike previous published studies this article was aimed to monitor the relationship between electrolyte temperature and resulting AAO layer thickness in interaction with other input factors affecting during anodizing process under special process condition, i.e. lower concentration of sulphuric acid, oxalic acid, boric acid and sodium chloride. According to Design of Experiments (DOE) 80 individual test runs of experiment were carried out. Using statistical analysis and artificial intelligence for evaluation, the computational model predicting the thickness of oxide layer in the range from 5 / μm to 15 / μm with tolerance ± 0,5 / μm was developed