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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.
881

IP-Based Networking as Part of the Design of a Payload Control System

Horan, Stephen, Aaronscooke, Ryan, Jaramillo, Daniel 10 1900 (has links)
ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / As part of a project to develop small satellites, we have developed a combined ground station and flight computer that use IP-based networking for the command and telemetry data communications. The network uses a private IP network between the payload and the ground-station. Commands are sent to the payload as UDP short message packets. Status and real-time telemetry are sent as UDP text strings. Production data are sent as files using a ftp-type of data exchange. Production data types include numeric data (sensor data) and JPEG-formatted picture data (full pictures and thumbnails). Details of the software used, challenges of making the system work over a low-quality radio link, and integration with the operating system will be discussed.
882

Designing an Object-Oriented Data Processing Network

Yang, Hsueh-szu, Sadia, Nathan, Kupferschmidt, Benjamin 10 1900 (has links)
ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / There are many challenging aspects to processing data from a modern high-performance data acquisition system. The sheer diversity of data formats and protocols makes it very difficult to create a data processing application that can properly decode and display all types of data. Many different tools need to be harnessed to process and display all types of data. Each type of data needs to be displayed on the correct type of display. In particular, it is very hard to synchronize the display of different types of data. This tends to be an error prone, complex and very time-consuming process. This paper discusses a solution to the problem of decoding and displaying many different types of data in the same system. This solution is based on the concept of a linked network of data processing nodes. Each node performs a particular task in the data decoding and/or analysis process. By chaining these nodes together in the proper sequence, we can define a complex decoder from a set of simple building blocks. This greatly increases the flexibility of the data visualization system while allowing for extensive code reuse.
883

RANGE SAFETY CASE STUDY: WESTERN RANGE CENTRALIZED TELEMETRY PROCESSING SYSTEM (WR CTPS), A LARGE DISTRIBUTED GROUND SYSTEM

Mather, Jonathan, Shaw, Nancy 10 1900 (has links)
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper presents a case study of the Western Range Centralized Telemetry Processing Subsystem (WR CTPS). This system was developed by Lockheed Martin Integrated Systems and Global Services and L-3 Communications Telemetry-West as part of the Range Standardization and Automation (RSA) IIA program. Requirements included real-time simultaneous acquisition of 16 PCM streams at rates of up to 30M bits per second; real-time processing; and data display on workstations connected over a gigabit Ethernet network. This system is designed for range safety and needs to be fault-tolerant while maintaining 100 percent data availability in the event of a single failure during an operation. The development of such a system demanded a rigorous Systems Engineering approach to ensure the successful upgrade and deployment onto the range infrastructure. This case study provides an overview of the system technical requirements and its architecture. The summary presents challenges encountered during the development and lessons learned while meeting them.
884

Low energy ground cooling system for buildings in hot and humid Malaysia

Sanusi, Aliyah Nur Zafirah January 2012 (has links)
This thesis presents an investigation into the viability of Low Energy Earth Pipe Cooling Technology in providing thermal comfort in Malaysia. The demand for air-conditioning in buildings in Malaysia affects the country escalating energy consumption. Therefore, this investigation was intended to seek for a passive cooling alternative to air-conditioning. By reducing the air-conditioning demand, there would be a higher chance of Malaysia government to achieve their aim in reducing CO2 emissions to 40 per cent by the year 2020, compared to 2005 levels. The passive technology, where the ground was used as a heat sink to produce cooler air, has not been investigated systematically in hot and humid countries. In this work, air and soil temperatures were measured on a test site in Kuala Lumpur. At 1m underground, the result is most significant, where the soil temperature are 6oC and 9oC lower than the maximum ambient temperature during wet and dry season, respectively. Polyethylene pipes were buried around 0.5m, 1.0m and 1.5m underground and temperature drop between inlet and outlet were compared. A significant temperature drop was found in these pipes: up to 6.4oC and 6.9oC depending on the season of the year. The results have shown the potential of Earth Pipe in providing low energy cooling in Malaysia. A parametric study on the same experiment was carried out using Energy Plus programme. Energy Plus data agreed with the field work data and therefore, this confirms Energy Plus is reliable to investigate Earth Pipe Cooling in Malaysia. Furthermore, thermal comfort of air at the Earth Pipe outlet was analyzed and the result has shown that the outlet air is within the envelope of thermal comfort conditions for hot/humid countries
885

Prediction of Strong Ground Motion and Hazard Uncertainties

Tavakoli, Behrooz January 2003 (has links)
The purpose of this thesis is to provide a detailed description of recent methods and scientific basis for characterizing earthquake sources within a certain region with distinct tectonic environments. The focus will be on those characteristics that are most significant to the ground-shaking hazard and on how we can incorporate our current knowledge into hazard analyses for engineering design purposes. I treat two particular geographical areas where I think current hazard analysis methods are in need of significant improvement, and suggest some approaches that have proven to be effective in past applications elsewhere. A combined hazard procedure is used to estimate seismicity in northern Central America, where there appear to be four tectonic environments for modeling the seismogenic sources and in Iran, where the large earthquakes usually occur on known faults. A preferred seismic hazard model for northern Central America and the western Caribbean plate based on earthquake catalogs, geodetic measurements, and geological information is presented. I used the widely practiced method of relating seismicity data to geological data to assess the various seismic hazard parameters and test parameter sensitivities. The sensitivity and overall uncertainty in peak ground acceleration (PGA) estimates are calculated for northwestern Iran by using a specific randomized blocks design. A Monte Carlo approach is utilized to evaluate the ground motion hazard and its uncertainties in northern Central America. A set of new seismic hazard maps, exhibiting probabilistic values of peak ground acceleration (PGA) with 50%, 10%, and 5% probabilities of exceedance (PE) in 50 years, is presented for the area of relevance. Disaggregation of seismic hazard is carried out for cities of San Salvador and Guatemala by using a spatial distribution of epicenters around these sites to select design ground motion for seismic risk decisions. In conclusion, consideration of the effect of parameters such as seismic moment, fault rupture, rupture directivity and stress drop are strongly recommended in estimating the near field ground motions. The rupture process of the 2002 Changureh earthquake (Mw = 6.5), Iran, was analyzed by using the empirical Green’s function (EGF) method. This method simulates strong ground motions for future large earthquakes at particular sites where no empirical data are available.
886

COMMAND CENTER FOR THE SDI DELTA 181 SENSOR MODULE

Heins, Robert J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / An orbiting sensor module, designed by The Johns Hopkins University Applied Physics Laboratory (JHU/APL), performed a number of significant Strategic Defense Initiative (SDI) Delta 181 program experiments. These experiments required on-orbit command and monitor operations involving a worldwide network of ground facilities. A major component was the sensor module command center (SMCC), which was designed and integrated by JHU/APL. The SMCC, located at Cape Canaveral Air Force Station (CCAFS), connected to a network of Eastern Test Range, Air Force Satellite Control Network (AFSCN), Kennedy Space Center, and Western Test Range assets. The complex nature of the mission presented numerous challenges to the design, integration, and operation of the SMCC. This paper presents a functional overview of SMCC design as well as unique aspects of supporting ground network telemetry and command operation.
887

Koppling av grundvattenmodell och jordmodell med en geoteknisk sättningsmodell / Coupling of Groundwater Modeling and Geotechnical Settling Rate Calculations

Adrian, Lindqvist January 2016 (has links)
Ur ett byggtekniskt perspektiv kan en sänkning i grundvattenytan i en sluten akvifer i ett område med lerjordar ge sättningar som kan skada byggkonstruktioner. Kopplingen mellan hydrogeologi och geoteknik är tydlig men oftast görs grova uppskattningar av konsekvenserna av en grundvattensänkning. Detta beror på att sättning vanligen beräknas i enskilda punkter där data finns att tillgå vilket endast ger resultat för sättningsberäkningar i dessa punkter. Ytor emellan punkterna utelämnas ofta. Dessutom är det inte vanligt att grundvattensänkningen beräknas med etablerade mjukvaruverktyg som Modflow för att få en mer detaljerad bild av avsänkningen och påverkansområdet.Denna studie kopplar samman en numerisk grundvattenmodell simulerad med Modflow samt en jordmodell, framtagen och interpolerad med kriging, med sättningsberäkningar. Detta resulterar i en integrerad modell som har till syfte att generera översiktskartor med predikterad sättning som resultat av grundvattensänkningar i utvalt område. Den integrerade modellen och sättningsberäkningarna är programmerade till denna studie med beräkningsverktyget Octave. Den integrerade sättningsmodellen testas på en fallstudie med verkliga geotekniska och hydrogeologiska data från ett område i Mälardalen. I fallstudien har ett hypotetiskt fall av grundvattensänkning simulerats. Grundläggande hydrogeologisk teori för slutna akviferer används för att bedöma vilka laster och ökad effektiv spänning grundvatten-sänkningar ger upphov till i jorden för fallstudien.Resultaten, i form av meter sättning, från den integrerade sättningsmodellen har verifierats mot beräkningar i programvaran Geosuite Settlement som är ett erkänt verktyg för sättningsberäkningar. Det visar sig att den integrerade sättningsmodellen beräknar sättningar med stor noggrannhet. Resultatet från grundvattenmodellen jämförs med en kriginginterpolerad grundvattenyta baserad på mätningar i grund-vattenrör i området. Grundvattenmodellen har i sin tur jordmodellen integrerad samt en vattenbalans som båda är baserade på verkliga data.Resultaten från fallstudien visar att oväntat stora sättningar kan förekomma i områden som ligger relativt långt ifrån källan för grundvattenavsänkningen. Detta motiverar användandet av en sådan metod för att bedöma risken för sättning.Till fallstudien har tre olika jordmodeller använts både i simulering av grundvattenströmning och simulering med den integrerade sättningsmodellen. De tre jordmodellerna skiljer sig åt så till vida att de har olika mängd data som kriginginterpolationen grundar sig på, det innebär också olika datatäthet i jordmodellerna. Detta har till syfte att undersöka hur sättningsbilden påverkas av datatätheten i jordmodellen och även hur grundvattenmodellen respektive sättningsmodellen påverkas. Resultaten i respektive modell påverkas inte mer än försumbart av datatätheten i jordmodellen visar fallstudien. / From a construction engineering point of view groundwater drawdown in a confined aquifer can result in ground subsidence that can damage buildings and constructions. The connection between hydrogeology and soil mechanics is clear, however when estimating ground settlement as a result of groundwater drawdown the estimations are often rough. This is due to that settlement is traditionally calculated with methods that only allow calculations in single points where geotechnical data is estimated. Areas between these points are often left out of the calculations. Groundwater drawdown is seldom simulated with acknowledged software programs like Modflow when estimating groundwater lowering and the affected area.This study combines a groundwater model simulated in Modflow and a soil strata model, interpolated with Kriging, with settlement calculations. This ends up as a an integrated soil settlement model which has the purpose to generate overview maps over areas that are sensitive to settlement as a result of ground water lowering. The integrated model is programmed in Octave for this study. The model is then tested with a case study that uses data from a real construction project in the area of Mälardalen. A hypothetical case of ground water lowering is simulated for the case study. Fundamental hydro-geological theory is used to estimate loads and effective stresses from the lowering of the water table.The result from the integrated model has been validated against calculations of settlement in the software Geosuite Settlement which is an acknowledged method for settlement calculations. This shows that the integrated model calculates settlement with great precision. The modeled initial ground water table is compared with a kriginginterpolated groundwater table which is based on data from ground water pipes in the area. Based on the comparison the initial ground water conditions simulated in Modflow are accepted. This simulated ground water model has the soil model and also a water balance integrated.The results from the case study show that unexpectedly large ground settlements can occur even far from the source of the ground water lowering.For the case study three different soil models are used, both in the ground water model and in the integrated model. The soil models differ in a way that they are based on different amounts of data from which the kriging interpolation is done. The purpose for this is to investigate what effects this might have on the ground water model and the integrated model respectively. The results from these different simulations show insignificantly small differences.
888

X-33 TELEMETRY BEST SOURCE SELECTION, PROCESSING, DISPLAY, AND SIMULATION MODEL COMPARISON

Burkes, Darryl A. 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / The X-33 program requires the use of multiple telemetry ground stations to provide continuous coverage of the launch, ascent, re-entry and approach phases for flights from Edwards AFB, California, to landings at Dugway Proving Grounds, Utah, and Malmstrom AFB, Montana. This paper will discuss the X-33 telemetry requirements and design, including information on the fixed and mobile telemetry systems, automated best source selection system, processing/display support for range safety officers (RSO) and range engineers, and comparison of real-time data with simulated data using the Dynamic Ground Station Analysis model. Due to the use of multiple ground stations and short duration flights, the goal throughout the X-33 missions is to automatically provide the best telemetry source for critical vehicle performance monitoring. The X-33 program was initiated by National Aeronautics and Space Administration (NASA) Cooperative Agreement No. NCC8-115 with Lockheed Martin Skunk Works (LMSW).
889

Satellite Ground Station Cost/Performance Appraisal

Massey, David E. 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The proliferation of Low Earth Orbiting (LEO) science, earth resources and eventually global communications satellites either in orbit or planned, requires a much lower cost methodology for ground support. No longer is it economically feasible to consider a single, dedicated satellite tracking station to service a LEO spacecraft. An innovative approach is needed to lower the cost of LEO satellite data services thus contributing to the expansion of the commercial space market. This appraisal will cover the performance aspects needed for LEO tracking support and offer a unique and new solution to providing TT&C and payload services.
890

Sustainability of water abstraction by hand drilling in the floodplain of River Benue of Yola, NE Nigeria

Apagu, Buba Ankidawa January 2014 (has links)
The aim of the research is to assess the sustainability of groundwater supply and the suitability of hand-drilling techniques for accessing groundwater for irrigation practices along the shallow alluvial floodplains of River Benue, NE Nigeria. Hand-drilling techniques are affordable means for the farmers to abstract water from these shallow aquifers. Determining the most sustainable hand-drilling techniques (taking into account the hydrology and sedimentology of the floodplain) will improve farming activities and food security in this region and the country at large. Hydrological data (obtained from fieldwork and modelling) demonstrate that the River Benue is the main source for recharge of the shallow alluvial aquifers of the floodplain during the dry season period. Water table heights were estimated by resistivity survey using ABEM Terrameter equipment and measured by automatic piezometer instruments. Floodplain sedimentology and hydrogeology were assessed at seventeen natural riverbank outcrops and twelve hand-drilled boreholes. At each location, sediment samples were collected from every exposed sedimentological unit. Locations and elevations were measured using a ProMark3 dual frequency GPS instrument, to create a detailed topographic map with updated contours. Twenty-four electrical resistivity sounding profiles and twelve-groundwater measurement were also obtained to explore the groundwater level of the floodplain. The resistivity results confirm the availability of water in the alluvial aquifers of the floodplain. In order to determine the most appropriate hand drilling techniques, a Field Shear Vane Tester was used to measure sediment shear strength at twelve different borehole locations. Shear strength forces were higher on clayey silt and sandy silt, and lower on sand formations. It appeared that in some areas of the floodplain, the farmers are already above the shear strengths that can be provided by human power. Hence, any increase of the hardness of the surface of the sediment would make low-cost hand drilling impractical. Particle size analysis for the sediment samples showed that the samples were largely sandy in nature, which enables easy movement of water through the layers for aquifer recharge. Magnetic susceptibility (used to classify the source of sediment and the process of their formation) revealed that the main source of the sedimentary materials was upstream of the study site and varies little over time. The groundwater level of the study area decreased away from River Benue valley during the dry season period. One perched aquifer formations and possibly two others were observed in three different locations, which reflects a low-permeability stratigraphic unit (such as lens of clayey silt) within alluvial sands. These should be avoided by farmers, as they are likely to provide water only in the short-term. Finally, groundwater modelling was undertaken (with various scenarios) for the River Benue floodplain using acquired sedimentology and hydrology data integrated into MODFLOW software. The results revealed that low-cost hand-drilling techniques such as augering and jetting remain possible for abstracting the shallow alluvial aquifers on the floodplain for irrigation farming in the study area, unless the most likely low river water stages in River Benue, over-exploitation of the shallow alluvial floodplain groundwater and drought scenarios occur.

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