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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

ADVANCED SUBMINIATURE TELEMETRY: A NEXT GENERATION INSTRUMENTATION SYSTEM

Harrison, William D., Copeland, Frank S. 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / In performing its mission, the Air Force SEEK EAGLE Office (AFSEO) conducts a wide variety of tests with heavy emphasis on open-air flight tests. As budget pressures drive a reduction in the number of test sorties, maximizing the amount of quality data from each flight test is of paramount importance. This paper describes an AFSEO effort to develop a low cost, intelligent, subminiature telemetry and sensor system based on modern commercial wireless technologies. The instrumentation system is completely self-contained and can be externally mounted, thus eliminating the requirement for extensive aircraft modifications and minimizing the need for specially instrumented test aircraft. The system will make maximum use of Commercial Off The Shelf (COTS) components to reduce cost and insure availability. MicroElectroMechanical Systems (MEMS) technology will be incorporated as the technology matures.
172

Buffelgrass Expansion Rate and Dispersal Type on Recently Invaded Barry M. Goldwater Range of Southwestern Arizona

Damery-Weston, Jaron January 2016 (has links)
Land managers have struggled to develop successful control strategies to address buffelgrass invasion in the Sonoran Desert. Two important variables for control strategies are dispersal type and patch expansion rate (i.e. satellite or invasion front). We investigated these variables along a highway invaded within the last 10 years located south of Gila Bend, Arizona, USA. Dispersal type was calculated by documenting the location of each buffelgrass individual along a 16 km stretch of highway and using an average nearest neighbor analysis in ArcMap 10.2.2. Thirty-six patches were monitored for four years along a 56 km stretch of highway 85 by documenting the outlines of each patch. Dispersal type registered as satellite dispersal (i.e. clustered on the Nearest Neighbor test), z-score = -47.2, p < 0.01. Patch expansion exhibited a median doubling time of 0.81 years. The results of the dispersal type analysis represent an opportunity to enhance control strategies, by targeting buffelgrass satellites and theoretically reducing patch expansion exponentially. The patch expansion rates for buffelgrass were faster than found in past research, giving land managers a clearer understanding buffelgrass patch expansion behavior.
173

Capture Method for Spread Spectrum Aloha Signals

Weibing, Fan, Qishan, Zhang 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / The concept and model of Spread Spectrum ALOHA (SS-ALOHA), as an important subject to develop dual-purpose satellite system in China, are described in this paper. The new synchronous code format and method for capturing the SS-ALOHA signals are presented and the process of correlation with surface-audio wave (SAW) is shown. The diagram of fast acquisition system and the results of experiment are given.
174

SUBMINIATURE TELEMETRY FOR MULTIPLE MUNITION (TECHNOLOGY TRANSITION)

Cullen J. M., Keller, Ed 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / The Instrumentation Technology Branch of Wright Laboratory Armament Directorate (WL/MNSI), has successfully completed an Exploratory Development (6.2) program to develop Subminiature Telemetry (SMT). SMT is a flexible, programmable telemeter with self calibration, power control and Direct Sequence Spread Spectrum modulation. The development program successfully demonstrated the ability of the SMT system to collect up to 64 analog and/or 128 digital discrete signals with programmable gain, bandwidth and offset. The program demonstrated a spread spectrum multiple-access technique that allows for simultaneous transmission and receipt of up to 96 different telemetry units within a 100 MHz telemetry band. WL/MNSI is conducting an Advanced Technology Development (6.3) program to continue development in this area. An air-worthy 4 channel spread spectrum demodulator was developed to support the SMT program but it is too costly for ground applications. The goals of this effort are to reduce the demodulator cost by a factor of 10 while increasing the capability for simultaneously processing data from 24 telemetry units and to support the first Technology Transition Plan (TTP) between WL/MN and the Air Force Development Test Center (AFDTC). The TTP will facilitate the transition of SMT spread spectrum technology to AFDTC for mission support over the next three years.
175

SPREAD SPECTRUM TT&C FOR THE SKYBRIDGE CONSTELLATION

Nasta, R., Gillot, J.-F. 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The SKYBRIDGE constellation will establish telecommunication and TTC links in Kuband, without any exclusive allocation of spectrum: jamming avoidance techniques are used in order to protect the geostationary satellites and associated ground stations that work in the same band. This paper presents the studies that have been carried out at system level.
176

A METHOD TO ENHANCE THE BIT RATE OF LINEAR CODE GENERATOR IN SPREAD-SPECTRUM COMMUNICATION SYSTEM

Xiaoyu, Dang, Yong, Zhang, Tingxian, Zhou 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Because of the limits of feedback devices, high-speed pseudo-noise code generators cannot depend simply on the improvement of clock rate. Based on the characteristic equation of linear feedback registers and the m-sequence sampling theory as well, deduction is made to indicate a novel way to improve the speed of pseudo-noise code generators 2^l (2^l < n, n is the length of registers) times as fast as the conventional one. Also, we extend our applications to non-reducible and non-primitive polynomials. It could be a good way to generate these linear codes at higher rates.
177

A PCMCIA BASED TELEMETRY AND ACQUISITION SYSTEM

Gross, Jeffrey, Keller, G. E. 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / In this paper, the Miniature Data Acquisition Transceiver System (Mini-DAT), a Type II PC-Card based data acquisition and transceiver system is described. The Mini-DAT was developed by ViaSat and is currently in use at the Air Force Research Lab (AFRL) at Eglin AFB. AFRL is investigating the use of this Industrial, Scientific and Medical (ISM) band system for data collection with advanced munitions. The Mini-DAT combines the advantages of PC-Card technology with an off the shelf interfacing and packaging approach to provide a large array of capabilities in a very small package. The system provides everything needed to collect analog, discrete and digital data, process the data and transfer the data in a wireless fashion using the latest license free spread spectrum modulation technology. The advanced design of the Mini-DAT allows for operation in harsh remote environments, collecting data unattended and accessed remotely. A graphical user interface (GUI) is provided via a Windows 3.x and 95 software package that can be easily customized for specific applications. The Mini-DAT provides fast and reliable error-free data transfer over the 2.4GHz ISM communication band. It operates over a shared 80MHz bandwidth, allowing multiple access of a number of portable units operating simultaneously in the same band.
178

A SYNCHRONOUS REAL TIME NETWORK BASED WIRELESS AIRBORNE DATA ACQUISTION SYSTEM

Long, Mark A., Zymowski, Paul H. 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / The purpose of this paper is to present a chronology from a Small Business Innovation Research Program (SBIR) showing the impact of a wireless network architecture on future airborne data acquisition systems. The major advantages and challenges associated with the use of wireless network data acquisition versus wired time division multiplexing systems are rooted in data latency, bandwidth efficient data transmission while maintaining a low bit error rate and not interfering with existing avionics. Many of the issues raised are subtle and complex. It is not the intent of this paper to give these issues the thorough academic and technical analysis they deserve. It is the hope of the authors that this paper will generate awareness and discussion on these issues.
179

Ecosystem Transformation by Buffelgrass: Climatology of Invasion, Effects on Arizona Upland Diversity, and Remote Sensing Tools for Managers

Olsson, Aaryn D. January 2010 (has links)
Invasive species drive ecosystem changes throughout the world. Introduced grasses in dryland ecosystems have driven a grass-fire cycle that transforms ecosystems into homogenized grasslands (Brooks et al. 2004; D'Antonio & Vitousek 1992). Little is known about the spread rates of these grasses, effects on native ecosystems or how climate modulates spread, yet these uncertainties may be the difference between success and failure. Equally important is a quantitative assessment of the current states of invasion, yet mapping efforts have been lacking and remote sensing assessments have been inadequate for regional and local assessments. This research examines these uncertainties in the context of buffelgrass (Pennisetum ciliare Link (L.)), a C₄ grass introduced into the Sonoran Desert. These are presented as three distinct but related studies. The first study documents changes in diversity and dominance at 11 sites in the Sonoran Desert with respect to time since infestation by buffelgrass. Dominant and rare species alike declined rapidly following infestation, although the longer-lived shrubs showed no signs until after five years. This calls into question basic assumptions about the grass-fire cycle. The second study assesses constraints to successful operational identification of buffelgrass via remote sensing. We combined ground-based spectral measurements with cover estimates and found that Landsat TM-based classification will result in high commission/omission errors regardless of timing. We also identified several spectral characteristics that distinguish buffelgrass that are only available using hyperspectral imagery. The third study reconstructs spread of buffelgrass using historical aerial photography dating from 1979. Populations grew from small colonizing patches to 66 ha in 2008, doubling every 2-3 years since 1988. Although spread closely fit a logistic growth curve between 1989 and 2008, we found evidence that the 1980s were a period of rapid expansion. Thus, we may presently be in a period of slower spread in which treatment efforts will be more effective than the long-term average. This research documents grass-led ecosystem transformation without changes in the fire regime and constant spread rates over multiple decades. Along with suggested methods derived from our remote sensing study, this provides managers with critical information for managing buffelgrass in the long-term.
180

Veltinio tradicijos ir sklaidos galimybės Lietuvoje / Felt traditions and promotion possibilities in Lithuania

Skripkaitė, Daiva 15 June 2011 (has links)
Magistro baigiamajame darbe „Veltinio tradicijos ir sklaidos galimybės Lietuvoje“ nagrinėjamas veltinis, jo kilmė, istorinė raida, tradicijos ir paplitimas Lietuvoje, Europoje bei visame pasaulyje. Taip pat aprašomos pagrindinės vėlimo technikos ir dekoravimo būdai. Aptariamos Lietuvoje vykstančios veltinio parodos ir simpoziumai, viešos veltinio vėlimo akcijos ir demonstracijos, veltinio instaliacijos bei performansai, kurių pagrindinis elementas yra veltinys. Veltinio parodų, simpoziumų pagrindinis tikslas- šios tekstilės rūšies tradicijų tąsa, populiarinimas, pasikeitimas kūrybine patirtimi, informacine medžiaga, sukurtų kūrinių eksponavimas įvairiuose Lietuvos ir užsienio miestuose. Darbe nagrinėjamas šiuolaikinis profesionalus ir mėgėjiškas veltinio menas, aptariamos šiuolaikinio veltinio meno pristatymo galimybės visuomenei. Aptariama menininkų, išradingai naudojančių savo darbuose veltinį, kūryba. Kadangi velti gali ne tik profesionalai, bet ir mėgėjai, darbe pristatomi veltinį Lietuvoje praktikuojantys dailininkai profesionalai bei veltinio populiarintojai mėgėjai, tautodailininkai; aptariami jų surengti veltinio darbų pristatymai bei parodos. Parodomos plačios šios technikos taikymo ne tik profesionalų, bet ir mėgėjų kūryboje galimybės. Veltinys šiuo metu tampa itin naudojamas šiuolaikinio meno instaliacijose, performansuose, eksperimentinėje animacijoje, interjero ir eksterjero pano, kuriant unikalias medžiagas drabužių dizainerių kolekcijoms, meno terapijoje... [toliau žr. visą tekstą] / The research object of the Master Thesis “Felt Traditions and Promotion Possibilities in Lithuania” is felt, its origins, historical development, traditions and spread in Lithuania, Europe and all over the world. The thesis reveals the main felting techniques and decoration methods and introduces organised in Lithuania felt exhibitions and symposiums, public felting actions and demonstrations, felt installations and performances in which basic element is felt. The main objective of felt exhibitions and symposiums is follow-up and popularisation of such textile traditions as well as exchange of creative experience, information material and demonstration of the textile items in different places throughout Lithuania and abroad. The thesis deals with modern professional and amateur felt craft, discusses possibilities of modern felt craft introduction to society. The thesis includes the review of creation of artists inventively using felt in their works. Since felting may be done not only by professionals, but also by amateurs, the thesis introduces Lithuanian professional artists using felt in their works as well as felt promoters amateurs and folk artists and organised by them felt works displays and exhibitions. The thesis reveals a wide field for application of such techniques not only by professionals, but also by amateurs. Presently felt becomes very popular in modern art installations, performances, experimental animation, interior and exterior panel, for the... [to full text]

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