International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / In this paper, the research prototype of a high-performance GPR imaging system is presented. The system is equipped with the capability of synthetic-aperture scan, stepfrequency FMCW illumination, and high-resolution tomographic image reconstruction.

The aim of this thesis is to locate current problems concerning the process of finding common ground between a creative producer and its respective client, furthermore it aims to propose a solution to this problem in the context of collaborative video editing. The paper starts off by exploring research related to the topic. After that, it establishes, through interviews with experts within fields of video editing and graphic design, what the currently existing problems are concerning communication within their line of work. As a solution to these problems, a collaborative software is proposed with the idea of bridging the understanding between the video editor and its client. The paper ends with some conclusions surrounding the current state of the topic and proposes a way forward for both practitioners and researchers.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / CCSDS recommendations initially addressed the communication link between spacecraft and ground station. Space Link Extension (SLE) is a set of CCSDS recommended standards for extending the link to control centers, allowing distributed access to space link telecommand and telemetry services. The recommendations encompass the specification of both services and access methods. This paper discusses an implementation of SLE that will be used to provide Forward CLTU service to the upcoming INTEGRAL (International Gamma Ray Astrophysics Laboratory) mission.

Thesis (PhD) -- Stellenbosch University, 2005. / ENGLISH ABSTRACT: The effective use of borehole radar in geophysical exploration requires accurate knowledge of the dielectric properties of the geological system in which it is employed. The attenuation and propagation velocity of pulses through rock must be known in order to plan and interpret experimental data. Conventional destructive methods for the measurement of hard rock cores require the careful preparation of samples. This firstly necessitates the selection of sampling position and the resulting estimation of rock properties based on sparse measurements, and secondly results in the loss of material and thus data. The ready availability of cylindrical borehole core samples invites the use of a nondestructive means of measuring their properties. A novel design for a flexible guarded capacitor which conforms to a core's cylindrical surface is presented here. T he proposed device has numerous advantages over previous methods. No material is lost to sample preparation and a detailed characterisation of the entire core, including inclusions and transitions between rock types, may be performed. A detailed methodology for the rapid construction of a robust capacitor is given. Guidelines for its operation to achieve repeatable and accurate measurements of the complex dielectric constant of samples of varying homogeneity in the 1- 25 MHz frequency range are presented. The increased amount of data collected from complete core samples is analysed statistically, and amongst other things allows the estimation of the rock's homogeneity. Comparisons of the dielectric properties measured in the laboratory to propagation velocity estimates obtained from crosshole borehole shoots show that a more homogeneous sample is a better predictor of bulk propagating conditions. Detailed studies of the dielectric properties of economically important diamondiferous and platiniferous geological systems show that borehole radar is a feasible tool for the high resolution delineation of ore bodies and other geological targets. / AFRIKAANSE OPSOMMING: Die effektiewe gebruik van boorgatradar in geofisiese eksplorasie benodig akkurate kennis van die dielektriese eienskappe van die geologiese sisteme waarin dit gebruik word. Kennis van die verswakking en voortplantingsnelheid van pulse deur die rots word benodig om eksperimente te beplan en gemete data te interpret eer. Vir konvensionele destruktiewe meetmetodes van harde rotskerne is noukeurige voorbereiding van monsters noodsaaklik. Hierdie proses vereis eerstens 'n keuse van meetposisies en die afskatting van rotseienskappe gebaseer op verspreide metings, en lei tweedens tot die verlies van materiaal en dus data. Die beskikbaarheid van silindriese bom·gat kernmonsters maak dit moontlik om die kerneienskappe op n nie-destruktiewe manier te meet. Die ontwerp van 'n nuwe buigbare afgeskermde kapasitor wat op 'n silindriese kernoppervlak pas, word hier voorgestel. Die toestel het verskeie voordele bo huidige metodes. Geen materiaal word gedurende monstervoorbereiding verloor nie, en 'n volledige beskywing van die eienskappe van die hele kern , met insluitings en oorgange tussen rotstipes, kan verkry word. 'n Gedetaileerde prosedure vir die vinnige konstruksie van 'n robuuste kapasitor word gegee. Die gebruik van die toestel vir herhaalbare en akkurate metings van die komplekse dielektriese konstante van verskillend homogene monsters in die 1- 25 MHz frekwensie bereik word beskryf. Die groter hoeveelheid data wat deur middel van hierdie metode van hele kernmonsters verkry kan word , word statisties geanaliseer, en laat onder andere 'n skatting van die rots se homogeniteit toe. Vergelykings van laboratoriumgemete rotseienskappe met veldskattings van voortplant ingsnelhede wys dat 'n meer homogene monster tot 'n beter afskatting van werklike voortplantingstoestande lei. Studies van die dielektriese eienskappe van ekonomies belangrike diamanthoudende en platinumryk geologiese sisteme wys dat boorgatradar geskik is vir hoe resolusie uitkenning van ertsligame en ander geologiese teikens.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / The National Oceanic and Atmospheric Administration (NOAA) Jason Ground System (NJGS) is a consolidated next-generation ground system that will support the simultaneous operation of the OSTM/Jason-2 and Jason-3 ocean surface topography missions. The NJGS will consist of several independent subsystems for spacecraft command and control, telemetry processing, and data archiving and distribution. The existing NOAA Jason-2 Ground System (J2GS) was designed around the concept of subsystem "strings", in which two complete sets of subsystems acted in primary and standby roles. For the NJGS, this concept is replaced with subsystem-level redundancy, in which two or more instances of each subsystem independently provide redundant capabilities. This paper discusses the design elements involved in the provision of a ground system architecture providing redundancy at the subsystem level. The paper focuses on the interaction between primary and standby subsystems and the mechanism through which failover capabilities are provided across the ground system.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / Commercial off-the-shelf (COTS) graphics processing units (GPU) perform the signal processing operations needed for video games and similar consumer applications. The high volume and competitive nature of that industry have produced inexpensive GPUs with impressive amounts of signal processing power. These devices use parallel processing architectures to execute DSP algorithms far faster than single, or even multi-core central processing units typically found in workstations. This paper describes a project which improves the performance of a radar telemetry application using the NVidia™ brand GPU and CUDA™ software, although the results could be extended to other devices.

No description available.

<p>Interception av snö eller regn på trädkronor är en viktig del av det hydrologiska kretsloppet. Upp till en tredjedel av all snö som faller över skogsområden når aldrig marken på grund av stora avdunstningsförluster av interceptionsförrådet, vilket minskar vårflöden i älvar. Goda prognoser av dessa flöden är viktiga för vattenkraftsindustrin. För att kunna förbättra modeller, i vilka interceptions-avdunstningsprocessen ingår, krävs lämpliga mätmetoder för interceptionförrådet av snö. Syftet med detta arbete var att undersöka om impulsradarutrustning kan användas för att mäta interceptionsförrådet av snö på barrträd. Metoden bygger på att mäta hastigheten och utsläckningen hos en elektromagnetisk impulsvåg, vilken skickas från en sändarantenn genom ett avsnitt skog till en mottagarantenn. Både utsläckningen och hastigheten påverkas av snö och vatten på trädens kronor, och kan med så kallade blandningsformler relateras till mängd vatten. Blandningsformler beskriver de elektromagnetiska egenskaperna hos heterogena material. Laboratorietester visade att interception av flytande vatten på små trädkronor gav upphov till förändringar av impulsvågens hastighet och utsläckning mätbara med radarutrustningen. Uppskattningar av mängden intercepterat vatten från radarmätningarna gav en överskattning jämfört med oberoende referensmätningar, däremot stämde relativa variationer väl överens mellan mätningarna. Tydliga samband mellan impulsvågens utsläckning och mängden intercepterat vatten kunde inte bestämmas från experimenten. Utsläckningsresultaten var svårtolkade och lämpliga blandningsformler hittades inte i litteraturen. Metoden testades även en vecka i fält i norra Sverige. Trots att installationen inte var den bästa visade resultaten ändå god överensstämmelse mellan uppskattade förändringar av interceptionsförrådet från radarmätningarna, och observerade väderförändringar samt oberoende referensmätningar med en trädvågsanordning. Resultaten tyder på att metoden kan ge goda uppskattningar av interceptionsförrådet, då en väl fungerande installation av utrustningen används och efter att vidare kalibreringsförsök genomförts.</p> / <p>Interception of rain or snow in forest canopies is an important component of the hydrological cycle. Up to one third of the total winter precipitation never reaches the ground in forest areas due to evaporation losses of intercepted snow, which reduces spring-time water flow in rivers. Accurate spring flow predictions are important for the hydro-power industry. Appropriate measurement methods of intercepted snow are needed in order to improve models involving the interception evaporation process. The aim of this study was to explore the possibilities of an impulse radar system to measure the snow interception storage on coniferous trees. The method is based on measurements of the velocity and attenuation of an electromagnetic impulse wave, generated in a transmitting antenna and sent through a forest section and detected by a receiving antenna. The attenuation and velocity is affected by ice and water in the canopy air space, and can be related to amounts of water using so-called mixing formulas that describe the average electromagnetic properties of heterogeneous materials. Controlled laboratory measurements on small canopies showed that interception of liquid water was well above the detectable limits of the radar system, with respect to both attenuation and velocity changes. Estimations of the mass of intercepted water based on velocity changes overestimated the reference measurements, but relative variations were well captured. No clear relation could be found between amount of water on canopies and impulse wave attenuation from the experiments. The attenuation results were difficult to interpret, and appropriate mixing formulas were not found in the literature. The method was further tested for one week under field conditions in northern Sweden. In spite of a non-optimal equipment installation results of estimated changes of the interception storage showed a good agreement with observed weather variations and reference measurements using a tree weighing device. The method can have good conditions to give correct estimations of the snow interception storage, using appropriate installation and further calibration measurements.</p>

<p>In this report we describe simulation of the surface current density on a PEC cylinder and the diffracted field for a line source above a finite PEC ground plane as a means to verify the Nero2D program. The results are compared with the exact solution and give acceptable errors. A terrain model for a communication link is studied in the report and we simulate the wave propagation for terrain with irregular shapes and different materials. The Nero2D program is based on the fast multipole method (FMM) to reduce computation time and memory. Gaussian sources are also studied to make the terrain model more realistic</p>

The purpose of this thesis is to conduct a detailed examination of the forward-directivity characteristics of near-fault ground motions produced in the 2010-11 Canterbury earthquakes, including evaluating the efficacy of several existing empirical models which form the basis of frameworks for considering directivity in seismic hazard assessment. A wavelet-based pulse classification algorithm developed by Baker (2007) is firstly used to identify and characterise ground motions which demonstrate evidence of forward-directivity effects from significant events in the Canterbury earthquake sequence. The algorithm fails to classify a large number of ground motions which clearly exhibit an early-arriving directivity pulse due to: (i) incorrect pulse extraction resulting from the presence of pulse-like features caused by other physical phenomena; and (ii) inadequacy of the pulse indicator score used to carry out binary pulse-like/non-pulse-like classification. An alternative ‘manual’ approach is proposed to ensure 'correct' pulse extraction and the classification process is also guided by examination of the horizontal velocity trajectory plots and source-to-site geometry. Based on the above analysis, 59 pulse-like ground motions are identified from the Canterbury earthquakes , which in the author's opinion, are caused by forward-directivity effects. The pulses are also characterised in terms of their period and amplitude. A revised version of the B07 algorithm developed by Shahi (2013) is also subsequently utilised but without observing any notable improvement in the pulse classification results. A series of three chapters are dedicated to assess the predictive capabilities of empirical models to predict the: (i) probability of pulse occurrence; (ii) response spectrum amplification caused by the directivity pulse; (iii) period and amplitude (peak ground velocity, PGV) of the directivity pulse using observations from four significant events in the Canterbury earthquakes. Based on the results of logistic regression analysis, it is found that the pulse probability model of Shahi (2013) provides the most improved predictions in comparison to its predecessors. Pulse probability contour maps are developed to scrutinise observations of pulses/non-pulses with predicted probabilities. A direct comparison of the observed and predicted directivity amplification of acceleration response spectra reveals the inadequacy of broadband directivity models, which form the basis of the near-fault factor in the New Zealand loadings standard, NZS1170.5:2004. In contrast, a recently developed narrowband model by Shahi & Baker (2011) provides significantly improved predictions by amplifying the response spectra within a small range of periods. The significant positive bias demonstrated by the residuals associated with all models at longer vibration periods (in the Mw7.1 Darfield and Mw6.2 Christchurch earthquakes) is likely due to the influence of basin-induced surface waves and non-linear soil response. Empirical models for the pulse period notably under-predict observations from the Darfield and Christchurch earthquakes, inferred as being a result of both the effect of nonlinear site response and influence of the Canterbury basin. In contrast, observed pulse periods from the smaller magnitude June (Mw6.0) and December (Mw5.9) 2011 earthquakes are in good agreement with predictions. Models for the pulse amplitude generally provide accurate estimates of the observations at source-to-site distances between 1 km and 10 km. At longer distances, observed PGVs are significantly under-predicted due to their slower apparent attenuation. Mixed-effects regression is employed to develop revised models for both parameters using the latest NGA-West2 pulse-like ground motion database. A pulse period relationship which accounts for the effect of faulting mechanism using rake angle as a continuous predictor variable is developed. The use of a larger database in model development, however does not result in improved predictions of pulse period for the Darfield and Christchurch earthquakes. In contrast, the revised model for PGV provides a more appropriate attenuation of the pulse amplitude with distance, and does not exhibit the bias associated with previous models. Finally, the effects of near-fault directivity are explicitly included in NZ-specific probabilistic seismic hazard analysis (PSHA) using the narrowband directivity model of Shahi & Baker (2011). Seismic hazard analyses are conducted with and without considering directivity for typical sites in Christchurch and Otira. The inadequacy of the near-fault factor in the NZS1170.5: 2004 is apparent based on a comparison with the directivity amplification obtained from PSHA.