Automatic search of missing people in avalanches

One of the main source of danger for people practising activities in mountain environments is avalanches. In the early 70s has been commercialized the first model of avalanche beacon transceiver: a device, composed by a transmitter and a receiver, specialized to the purpose of finding people buried under the snow. Since 2013, project SHERPA is working to develop ground and aerial robots to support human in the search of missing people in avalanches. The aim of this dissertation is to provide a way to interface an avalanche beacon receiver (ARTVA) with the autopilot module mounted on a quad-copter drone, and to study and realize a software implementation of two automatic search algorithms, with the intention of speeding up search operations with drones. First we will focus on interfacing the ARTVA system with a quad-copter autopilot module, named Pixhawk. This module embed a software, named PX4, which runs on a real-time operating system (RTOS), and have several connection ports, among which there is the serial one that we will use for our purpose. Then we will analyse how to use the data coming from the ARTVA receiver to construct and implement the two search algorithms. The idea is to generate set-points, based on the information coming from the avalanche beacon receiver, and use them to feed the position controller which is implemented in the PX4 firmware. Finally, we will execute simulations, provide results, and investigate if a practical implementation is possible and what are the relative issues

Small business innovation research. Abstracts of completed 1987 phase 1 projects

Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Satellite technology : reinforcement of computer data transmission technology : implications for the maritime world communications, data transfer and maritime education

This dissertation is a study of the impact of data transmission via satellite on the maritime world of communication, data transfer and education. The aim of the study is to understand the technological reinforcement of the maritime industry and the changes taking place in it. With the avalanche of changes that are taking place in the field of information technology, they can be used to facilitate the shipping industry. This dissertation assists in understanding some of the technological evolution of satellite technology and data communication and in the needs of the maritime industry as well. This dissertation describes satellite technology and data communication and analyses the data communication software (protocols), compression software, and other application software combinations with maritime communication system provided to improve ship operation and management for safety. The conclusion and recommendations chapter examines the implications of the technology changes on developing countries, the need to be harmonised in training and education for the maritime industry, maritime communication systems and the equipment, policy of shipping companies and communication costs

The search for and location of inhomogeneities in seasonal snowpacks utilizing ground-penetrating radar

The location of singular objects or layered transitions below the surface and properties thereof in the ground are a pivotal topic in geosciences. In mountainous regions is the investigation of objects and layer transitions specifically of interest for the seasonal snowpack, primarily to reduce the threat to humans and infrastructures by natural hazards. Snow avalanches are a major natural hazard causing numerous fatalities throughout the world and they are a direct consequence of snowpack conditions. The annual fatality numbers of avalanches are fairly constant for the last 30 years, while in other fields such as e.g. road traffic these numbers decreased significantly. It can be assumed that the permanent enhancements in active and passive safety systems in road traffic are the reason for the decrease in victim numbers. In the field of professional search and rescue operations or accident prevention in avalanches such as hazard forecast, enhancements of instrumentations are marginal for the last three decades. The present study describes two different assessments for the use of ground-penetrating radar (GPR) systems to improve the instrumentation for the location of buried avalanche victims and the prediction of avalanches. Consequently, it demonstrates the feasibility of radar systems for the detection of inhomogeneities in seasonal snowpacks. With regard to the improvement of current methods to search and locate buried avalanche victims, which are not equipped with a location device (e.g. avalanche beacon), the main objective is to shorten search time. The assessment of this thesis was therefore to use helicopter-borne non-invasive location methods. To simulate helicopter flights, test arrangements were designed to perform field tests from above the surface. I developed methods to measure from 6--12 m above the snow cover. To measure non-invasively, the arrangement is based on pulsed radar technology. To shorten search time and to minimize the influence of man-made error possibilities, an automatic location software was developed. The results of the field tests present the answers of the fundamental questions for an airborne location operation and enabled the development of a location algorithm. Measurements showed, that the sidewise detectable range of 3--5 m of an antenna set-up with one transmitter -- receiver pair is rather small for the given flight height of 6 to 12 m. Furthermore, the reflection amplitude of the snow surface decreases almost linearly with the flight height. Unfortunately, in wet snow avalanches a buried object in the snowpack does not appear as typical reflection pattern and is therefore not explicitly locatable. The developed software algorithm proved to be sufficient for all applied test arrangements in dry snow conditions. The algorithm is able to distinguish between buried victims in the snowpack and reflections caused by only air holes within the snow cover. Further implementations on helicopters can be achieved, based on these results, but more field tests are necessary to adapt the software to the rougher flight conditions in helicopters. Concerning the observation of stratigraphic inhomogeneities within a snowpack, this thesis showed that a record of specific snowpack conditions from beneath the snow cover is feasible with GPR. The assessment of the present work is to provide snowpack information in avalanche endangered slopes and to follow the temporal evolution of the snowpack over a whole season. Two different kinds of field measurements in dry and wet snow conditions were performed to ascertain the GPR set-up, which provides the best trade-off between penetration depth and layer resolution. On the one hand, temporally singular measurements at different locations, concerning altitude, snowpack conditions and climatic regions in the European Alps, enabled the determination of capable test arrangements. On the other hand, a temporal monitoring of the snow cover at a fixed position over several months, facilitated the record of the change of specific parameters in the snowpack. In terms of system parameters, antennas with a center frequency of about 800--900 MHz are able to penetrate and adequately record stratigraphic transitions in dry and wet snow conditions. The radar-measured snow height in dry snow using a mean wave speed value for the conversion of the two-way travel time was in a good agreement to the probed snow depth and arose in an uncertainty slightly higher than of ultrasonic sensors. In terms of snowpack parameters, the recorded signals of the various snow covers were in good agreement with the measured snow properties. For dry snow conditions, the appearance and the manner of reflections recorded in the snow cover corresponded to the size and the algebraic sign of the gradient in snow density. Moisture in the snowpack attenuates the radar signal significantly. This thesis presents encouraging results of the use of impulse radar technology for the location of inhomogeneities in seasonal snowpacks. Parts of the presented results and methodologies (e.g. the automatic location algorithm) are possibly easily adaptable in related areas of geoscientific research and could also provide advances in other, non-snow related fields

Facilitating Internet of Things on the Edge

The evolution of electronics and wireless technologies has entered a new era, the Internet of Things (IoT). Presently, IoT technologies influence the global market, bringing benefits in many areas, including healthcare, manufacturing, transportation, and entertainment. Modern IoT devices serve as a thin client with data processing performed in a remote computing node, such as a cloud server or a mobile edge compute unit. These computing units own significant resources that allow prompt data processing. The user experience for such an approach relies drastically on the availability and quality of the internet connection. In this case, if the internet connection is unavailable, the resulting operations of IoT applications can be completely disrupted. It is worth noting that emerging IoT applications are even more throughput demanding and latency-sensitive which makes communication networks a practical bottleneck for the service provisioning. This thesis aims to eliminate the limitations of wireless access, via the improvement of connectivity and throughput between the devices on the edge, as well as their network identification, which is fundamentally important for IoT service management. The introduction begins with a discussion on the emerging IoT applications and their demands. Subsequent chapters introduce scenarios of interest, describe the proposed solutions and provide selected performance evaluation results. Specifically, we start with research on the use of degraded memory chips for network identification of IoT devices as an alternative to conventional methods, such as IMEI; these methods are not vulnerable to tampering and cloning. Further, we introduce our contributions for improving connectivity and throughput among IoT devices on the edge in a case where the mobile network infrastructure is limited or totally unavailable. Finally, we conclude the introduction with a summary of the results achieved

Parametric analysis of microwave and laser systems for communication and tracking Quarterly report, 6 Mar. - 6 Jun. 1966

Parametric analysis of microwave and laser systems for communication and tracking - updated reference data for advanced space communication and tracking system

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion

NASA Tech Briefs, September 2008

Topics covered include: Nanotip Carpets as Antireflection Surfaces; Nano-Engineered Catalysts for Direct Methanol Fuel Cells; Capillography of Mats of Nanofibers; Directed Growth of Carbon Nanotubes Across Gaps; High-Voltage, Asymmetric-Waveform Generator; Magic-T Junction Using Microstrip/Slotline Transitions; On-Wafer Measurement of a Silicon-Based CMOS VCO at 324 GHz; Group-III Nitride Field Emitters; HEMT Amplifiers and Equipment for their On-Wafer Testing; Thermal Spray Formation of Polymer Coatings; Improved Gas Filling and Sealing of an HC-PCF; Making More-Complex Molecules Using Superthermal Atom/Molecule Collisions; Nematic Cells for Digital Light Deflection; Improved Silica Aerogel Composite Materials; Microgravity, Mesh-Crawling Legged Robots; Advanced Active-Magnetic-Bearing Thrust- Measurement System; Thermally Actuated Hydraulic Pumps; A New, Highly Improved Two-Cycle Engine; Flexible Structural-Health-Monitoring Sheets; Alignment Pins for Assembling and Disassembling Structures; Purifying Nucleic Acids from Samples of Extremely Low Biomass; Adjustable-Viewing-Angle Endoscopic Tool for Skull Base and Brain Surgery; UV-Resistant Non-Spore-Forming Bacteria From Spacecraft-Assembly Facilities; Hard-X-Ray/Soft-Gamma-Ray Imaging Sensor Assembly for Astronomy; Simplified Modeling of Oxidation of Hydrocarbons; Near-Field Spectroscopy with Nanoparticles Deposited by AFM; Light Collimator and Monitor for a Spectroradiometer; Hyperspectral Fluorescence and Reflectance Imaging Instrument; Improving the Optical Quality Factor of the WGM Resonator; Ultra-Stable Beacon Source for Laboratory Testing of Optical Tracking; Transmissive Diffractive Optical Element Solar Concentrators; Delaying Trains of Short Light Pulses in WGM Resonators; Toward Better Modeling of Supercritical Turbulent Mixing; JPEG 2000 Encoding with Perceptual Distortion Control; Intelligent Integrated Health Management for a System of Systems; Delay Banking for Managing Air Traffic; and Spline-Based Smoothing of Airfoil Curvatures

NASA Thesaurus. Volume 2: Access vocabulary

The NASA Thesaurus -- Volume 2, Access Vocabulary -- contains an alphabetical listing of all Thesaurus terms (postable and nonpostable) and permutations of all multiword and pseudo-multiword terms. Also included are Other Words (non-Thesaurus terms) consisting of abbreviations, chemical symbols, etc. The permutations and Other Words provide 'access' to the appropriate postable entries in the Thesaurus