International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / NASA and the Air Force are increasing the number of hypersonic and access-to-space programs creating a growing requirement for flight test ranges over large regional areas. A principal challenge facing these extended test ranges is the ability to provide continuous vehicle communications by filling the gaps in coverage between fixed ground stations. Consequently, there is a need for mobile range systems that provide a multitude of communication services under varying circumstances. This paper discusses the functional design and systems capabilities, as well as the mission support criteria, concerning NASA’s Mobile Operations Facility (MOF). The MOF will be deployed to Dugway Proving Grounds (DPG), Utah, in support of the X-33 single-stage-to-orbit (SSTO) demonstrator.

International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, Nevada / Digital processing techniques and related algorithms for receiving and processing space vehicle downlink signals are discussed. The combination of low minimum signal to noise density (C/No), large signal dynamic range, unknown time of arrival, and high space vehicle dynamics that is characteristic of some of these downlink signals results in a difficult acquisition problem. A method for rapid acquisition is described which employs a Fast Fourier Transform (FFT). Also discussed are digital techniques for precise measurement of space vehicle range and range rate using a digitally synthesized number controlled oscillator (NCO).

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / The Ballistic Missile Defense Organization (BMDO) is developing new Theater Missile Defense (TMD) weapon systems to defend against the rapidly expanding ballistic missile threat. The tactical ballistic missile threats include systems with range capabilities greater than 1000 kilometers. The development and testing of systems such as the Patriot Advanced Capability 3 (PAC-3), the Theater High Altitude Area Defense (THAAD), Navy Area Defense, and the System Integration Tests (SIT) to address the interoperability of this family of systems, will require the development of the Transportable Range Augmentation and Control System for Multiple Shot Engagements (TRACS - MSE). Congress has mandated that these systems be tested in multiple simultaneous engagements. These systems will be tested at several ranges to meet all the developmental and operational testers' needs. Potential range locations include White Sands Missile Range (WSMR), Kwajalein Missile Range (KMR), the Pacific Missile Range Facility (PMRF) and the Gulf Range at Eglin Air Force Base. Due to the long distances separating the target launch site and the interceptor site, the TRACS - MSE will be required at multiple sites for each range used. To be cost effective, transportable systems should be developed to augment existing capabilities. Advances in Global Positioning System (GPS) technology and high data rate receivers make telemetry based solutions attractive. This article will address the requirements for range safety, for Time, Space, Position Information (TSPI) collection and processing requirements to support a TRACS - MSE capability.

Thesis (MSc)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: Arid and semi-arid rangelands of the Nama-Karoo Biome are believed to have changed considerably since the arrival of domestic livestock in the veld. Severe grazing pressure is considered to be one of the prime factors responsible for the perceived degradation of vegetation and concurrent soil degradation. To understand the process of degradation and to make further recommendations for future veld restoration, a large-scale project was undertaken in the Eastern Cape. This project focused on the role that landscape heterogeneity plays in providing refuges for plant species. The key question asked in this project was: What role do these hypothetically less grazed mesas play in the conservation of rangelands in the Nama-Karoo of the Eastern Cape? This study, a component of the larger project, investigated grazing and soil landscape gradients on- and off- the three mesas (Tafelberg, Folminkskop and Buffelskop) in the Middelburg District of the Eastern Cape, South Africa and the possible influences that they might have on the veld. The flats surrounding the mesas were mostly used as grazing camps in contrast to the plateaux of the mesas, which had varied levels of accessibility. In the absence of direct observations, the primary objective of the study was to test the differential dung pellet abundance and impact of animals on different parts of the landscape. As such, dung pellet counts in this study were correlated with surrogates of soil physical properties including bare ground, trampling and litter cover. Variation in dung pellet density was found at the different habitats (flats, slopes and plateaux) of all mesas. The flats to the north-eastern and south-western of Tafelberg mesa were found to be more heavily utilized by livestock and herbivores, while the plateaux and southeastern slopes of Folminkskop and Buffelskop were also utilized by grazers. The Tafelberg mesa was the only study site that was consistent with the hypothesis which stated that grazers would be less concentrated on the plateau compared to the surrounding flats due to its inaccessibility, whilst the high mean dung pellet density on the plateaux of the smaller Folminkskop and Buffelskop mesas due to easier access contradicted the original hypothesis. It appeared that dung pellet density did not clearly turn out to be an indicator of habitat use in this study, but showed where slopes and plateaux were accessible to herbivores, as in the case for the Buffelskop mesa, a higher abundance of dung pellets were found suggesting that higher intensities of habitat use took place. During this study a strong pattern was observed of bare soil patches on the flats surrounding the mesas. There was a decrease in percentage of bare soil along the gradient of the three mesas with a high percentage of bare soil on the plateaux of the mesas. A significant correlation was found between bare soil and dung pellet density. However, the plateaux of Folminkskop and Buffelskop had a high percentage of bare soil compared to the plateau of Tafelberg mesa. Farmers mainly used these smaller mesas as grazing camps for their livestock and herbivores. A positive correlation between bare soil and litter cover of the different habitats was evident in this study. A lower percentage of litter cover at these sites was associated with a high percentage of bare soil. Litter is very important in a healthy vegetation community in terms of nutrient cycling and fertile patches. A detailed assessment of soil chemical and physical properties would reveal, firstly, if vegetation change is better explained by soil or grazing effects and, secondly, if changes in soil have resulted from land use. Differences in macro- and micro-site variations between open-canopy (between shrubs) and closed-canopy (under shrubs) sites for each habitat were determined to differentiate between local scales due to land use and landscape scales due to geomorphology. The results suggested that carbon, phosphorus, calcium, magnesium, copper and manganese levels in soils at landscape scale better explain vegetation changes between habitats. At a local scale (open- and closed-canopy sites) land use was responsible for little changes in soils. Changes in only soil potassium, zinc and boron elements were actually a consequence of local scales due to land use. The soil nutrient content on the slopes appeared to be intermediate between the flats and plateaux of all three mesas. It appeared that dolerite capped Tafelberg and Folminkskop mesas had high silt and clay content, while Buffelskop (sandstone) mesa had a lower silt and clay content. Consequently, the texture and parent material of the soils contributed to the variations in soil nutrient composition between these mesas. High infiltration rate together with low nutrient content on the flats clearly showed that these flats, surrounding the mesas were degraded. The high infiltration rates were caused by high activity by livestock and other indigenous animals on the flats which breaks the surface crusting of bare soil and improve infiltration. It was concluded that high levels of grazing at these sites have also altered the textural and soil properties. Endozoochory dispersal and the deposition of dung pellets in areas of small patch disturbances play an important role in veld regeneration in degraded areas. Dung pellets collected from permanent study sites on the southeastern and northwestern flats and slopes, and all the study sites on the plateau of Tafelberg mesa, was sown in seedling trays, watered and monitored for seedling germination. Species list were then compared to below-ground soil seed bank data and above-ground vegetation data collected by other researchers at the same permanent study sites. Higher seedling percentages were recorded from dung pellets collected on the flats than on the plateau. A total of sixteen species were found to germinate in dung pellets collected on the flats compared to ten species germinating in dung pellets collected on the slopes and two species on the plateau of Tafelberg mesa. The seeds that germinated represent a variety of palatable grasses and shrub species. Aristida sp., Eragrostis bicolor, Eragrostis ch/orome/as and Eragrostis obtusa were palatable grasses recorded for dung pellets collected on the flats. Of the species recorded, Aristida sp., Chenopodium sp. and Pentzia sp. were found in dung pellets but were not recorded in parallel soil seedbank and vegetation studies. Successful restoration of veld conditions requires strict grazing management practices. Germination of seed in dung pellets might be considered to be a valuable means of indicating restoration potential and rangeland conditions for the identification of both degraded and conservation worthy areas. With appropriate land management skills and restoration measures, these challenges can be constructively and creatively faced. / AFRIKAANSE OPSOMMING: Daar word geglo dat die ariede en sernl-arlede weivelde van die Nama-Karoo bioom aansienlik verander het sedert die aankoms van mak lewende hawe in die veld. Swaar weidingsdruk word beskou as een van die vernaamste faktore verantwoordelik vir die waarneembare oorbeweiding van plantegroei en die gelyktydige grond agteruitgang (degradasie). Ten einde die proses van degradasie beter te verstaan, en om verdere aanbevelings te kan maak vir toekomstige veld herstel, is huidiglik 'n grootskaalse projek in die Oos-Kaap aan die gang oor die rol wat landskap ongelyksoortigheid speel in die voorsiening van skuiling aan plant spesies. Hierdie studie ondersoek weiding en grondlandskap gradiënte (op en af) van die drie mesas (Tafelberg, Folminkskop en Buffelskop) in die Middelburg streek van die Oos- Kaap, Suid-Afrika en die moontlike invloed wat hierdie gradiënte op die veld het. Die vlaktes was meestal gebruik vir weidingskampe in teenstelling met die kruin van die mesas. Hierdie studie het duidelike patrone vir habitat-gebruik op die vlaktes, hange en kruine van al die mesas aangetoon. Die vraag wat gestel was, was watter rol speel hierdie hipoteties minder beweide mesas in die bewaring van weivelde in die Nama- Karoo van die Oos-Kaap? Hierdie studie toets nie direk vir mis verspreiding as 'n plaasvervanger vir dier verspreiding in die landskap sedert werklike dier getalle nie oorweeg was nie. In die awesigheid van direkte waarneming, die primêre doelwit was om te toets die differensiaal misdigtheid en die impak van diere op verskillende dele van die landskap. Mis getalle in hierdie studie was gekorreleer met plaasvervangers van fisiese eienskappe insluitent onbedekte grond, vertrapping en droë plant material decking. Variasie in misdigtheid was gevind by die verskillende habitate (vlaktes, hange en kruine) van all die mesas. Die vlaktes aan die noord-oostelike en suid-westelike kante van die Tafelberg mesa was meer hewig benut deur lewende hawe en hêrbivore, terwyl die kruine en suid-oostelike hange van Folminkskop en Buffelskop ook gebruik was deur weidende diere. Die Tafelberg mesa was die enigste studie area wat konsekwent was met die hipotese, terwyl die hoë gemiddeld misdigtheid op die kruine van die kleiner Folminkskop en Buffelskop mesas, as gevolg van makliker toegang weerspreek die oorspronklike hipotese. Dit blyk dat misdigtheid duidelik opkom as 'n nie aanwyser habitat-gebruik in hierdie studie, maar wys well waar hange en kruine toeganklik was vir herbivore, soos in die geval van Buffelskop mesa, oorvloed van mis was gevind wat voorstel dat hoer intensiteit van habitat-gebruik voorgekom het. 'n Duidelike patroon is waargeneem tydens hierdie studie van onbedekte grond areas op die vlaktes rondom mesas. Daar was 'n afname in persentasie onbedekte grond langs die gradiënt van die drie mesas. Die kruine van Folminkskop en Buffelskop toon hoër persentasies onbedekte grond in vergelyking met die kruin van die Tafelberg mesa. Daar is 'n betekenisvolle korrelasie tussen onbedekte grond en misdigtheid gevind. Boere gebruik hierdie kleiner mesas hoofsaaklik as weidingskampe vir hulle lewende hawe en hêrbivore. In hierdie studie is daar 'n positiewe korrelasie gevind tussen onbedekte grond en droë plant material decking van die verskillende habitatte. Droë plantmateriaal bedekking speel 'n baie belangrik rol in 'n gesonde plant gemeenskap in terme van voedingsirkulering en vrugbare kolle. 'n Breedvoerige skatting van grond chemise en fisiese eienskappe wou openbaar eerstens of plantegroei verandering beter verklaar word deur grond of weiding effekte en tweedens, of verandering in grond veroorsaak was deur land-gebruik. Verskille in makro- en mikroterrein-wisseling tussen oop-blaredak (tussenplantruimtes) en toeblaredak (onderplantdekking) terreine vir elke habitat was bepaal om te onderskei tussen lokaal effek as gevolg van land-gebruik en landskap effek as gevolg van geomorfologie. Die resultate stel voor dat koolstof, fosfor, kalsium, magnesium, koper en mangaan vlakke in die grond by landskap effek beter plantegroei verandering tussen habitate verduidelik. By 'n lokaal effek (oop-en toe-blaredak terreine) land-gebruik was verantwoordelik vir min veranderinge in grond. Verandering in grond kalium, sink en baron elemente was werklik 'n gevolg van lokaal effek as gevolg van land-gebruik. Die nutrient inhoud van grond op die hange blyk intermediêr te wees tussen die van die vlaktes en kruine van al drie mesas. Hierdie studie toon ook dat die geologie en topografie van hierdie mesas die grond tekstuur en nutrient samestelling op en af van die mesas beinvloed. Dit wil voorkom asof die dolerite bedekte Tafelberg en Folminkskop mesas, hoë slik en klei materiaal bevat, terwyl Buffelskop (sandsteen) mesa 'n laer slik en klei inhoud het. Gevolglik, tekstueel en ouer materiaal grond dra by tot die variasie in grond nutrient samestelling tussen hierdie mesas. Hoë infiltrasie tempo tesame met lae voedingstof van die vlaktes dui daarop dat die vlaktes rondom die mesas oorbewei was. Hierdie hoë infiltrasie tempo word veroorsaak deur hoë dierlike aktiwieteite op die vlaktes deur lewende hawe en ander inheemse diere wat die oppervlakke van onbedekte grond versteur en infiltrasie verbeter. Die gevolgtrekking word gemaak dat die hoë weidingsvlakke van hierdie terreine ook die tekstuur en ander grond eienskappe verander het. Endozoochoreeuse verspreiding en die mis-afsetting in gebiede van klein areaversteurings, speel 'n belangrike rol in veld herlewing in oorbeweide gebiede. Mis versamel by permanente studie terreine op die SO en NW vlaktes en hange, as ook al die studie terreine op die kruin van die Tafelberg mesa, is gesaai in saailing bakke, besproei en gekontroleer vir saailing ontkieming. 'n Lys van spesies is vergelyk met onder-grondse saadbank gegewens en bo-grondse plantegroei gegewens wat deur ander navorsers by dieselfde studie terreine versamel was. Hoër saailing persentasies is gevind vir mis wat op die vlaktes versamel is as op die kruine. 'n Totaal van sestien geidentifiseerde spesies het uit die mis op die vlaktes ontkiem in vergelyking met die tien spesies wat ontkiem het uit die mis van die hange en twee spesies iut die mis van die kruin van Tafelberg mesa. Die ontkiemde saad verteenwoordig 'n verskeidenheid van vreetbare gras en struik spesies. Aristide sp., Eragrostis bicolor, Eragrostis chloromelas en Eragrostis obtusa is vreetbare grasse wat gevind was in die mis versamelop die vlaktes. Die spesies opname wys dat Aristida sp., Chenopodium sp. en Pentzia sp. Gevind was in die mis, maar nie in die parallelle grond saadbank en plantegroei studies nie. Die suksesvolle herstel van veldtoestande vereis "n streng weidingsbestuur toepassing. Die ontkieming van saad in mis kan beskou word as "n bekostigbare manier om veld herstel potentiaal te bepaal, asook weiveld toestande vir die indentifiseering van beide degradasie en bewaring van waardevolle areas. Met gepaste veldbestuur vaardighede en herstel maatreels, kan hierdie uitdagings konstruktief en kreatief aangespreek word.

Der vorliegende Beitrag beschäftigt sich mit Untersuchungen zur Entfernungsmessung terrestrischer Long-Range Laserscanner. Für diese Studie wurden dem Institut für Markscheidewesen und Geodäsie dankenswerter Weise von der Firma RIEGL ein Laserscanner VZ-4000 zur Verfügung gestellt. In diesem Beitrag werden der Versuchsaufbau erläutert und erste Ergebnisse des Soll-Ist-Vergleiches gezeigt. Die unterschiedlichen Einflussgrößen, wie Temperatur und Luftdruck, die bei Messungen auf große Entfernungen eine Rolle spielen, werden angesprochen. / This paper deals with actual researches for measuring distances of terrestrial long-range Laser scanners. The Institute for Mine Surveying and Geodesy had a laser scanner VZ-4000 by the company RIEGL easy and unconventional provided. The paper presents the experimental setup and the results of the target-actual comparison. Several influences, for example temperature and atmospheric pressure, are considered for long-range measurements.

Dans le contexte des réseaux de capteurs sans fil, la technique de localisation ”range-free” est plus efficiente, par rapport au principe ”range-based”. Par conséquent, nous avons focalisé nos travaux de cette thèse sur les techniques ”range-free”. Afin de permettre à chaque noeud mobile ou normal de choisir son propre algorithme de localisation, nous avons proposé un mécanisme adapté en scindant les noeuds normaux en deux classes: les noeuds de la première classe ont au moins 3 ancres voisines, alors que les noeuds de la deuxième classe ont moins de trois ancres voisines. Pour les noeuds normaux de la classe 1, nous avons proposé un nouvel algorithme ”Mid-perpendicular”. Pour les noeuds normaux de la classe 2, nous avons proposé deux nouveaux algorithmes ”Checkout DV-hop” et ”Selective 3-Anchor DV-hop”.Pour simuler et évaluer la performance de nos trois nouveaux algorithmes dans le contexte protocolaire des réseaux, nous avons pris soin de proposer deux protocoles associés : ”DV-hopprotocol” et ”Classe-1 protocol”. Par la suite, nous avons combiné ces deux protocoles pour obtenir notre ”adaptive range-free localization protocol”. Basé sur nos protocoles, en utilisant le simulateur WSNet, nous avons simulé différents algorithmes ”range-free” dans le contexte des réseaux de capteurs conformes au standard IEEE 802.15.4. Les résultats ont été présentés et analysés en termes de précision de la localisation, charge du réseau, mobilité des noeuds, et synchronisation de ces derniers. / In the context of wireless sensor networks, the range-free localization technique is more costeffective than the range-base scheme. Therefore, in this thesis we focus on the range-free technique.In order to permit each normal node to choose its suitable localization algorithm, we proposed anadaptive mechanism to categorize normal nodes into two classes: the normal nodes having at least 3 neighbor anchors are class-1 nodes, while others are class-2 nodes. For class-1 normal nodes, we proposed a new algorithm named as Mid-perpendicular. For class-2 normal nodes, we proposed twoalgorithms Checkout DV-hop and Selective 3-Anchor DV-hop.In order to simulate and evaluate the performance of our three new algorithms, we proposed two protocols: DV-hop protocol and Class-1 protocol. Then we combined these two protocols into our adaptive range-free localization protocol. Based on our protocols, using the network simulator WSNet,we simulate the concerned range-free localization algorithms in the IEEE 802.15.4 wireless network.The comparative network simulation results are presented and analyzed in terms of localization accuracy, overhead, node mobility, and node synchronization

Tung Wai Lan, Iris. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 92-101. / ACKNOWLEDGEMENTS / ABSTRACT / LIST OF FIGURES --- p.iii / LIST OF TABLES --- p.iv / CHAPTER / Chapter I --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Significance of the Research --- p.3 / Chapter 1.3 --- Objectives of the Research --- p.5 / Chapter 1.4 --- Organization of the Research --- p.5 / Chapter II --- LITERATURE REVIEW --- p.7 / Chapter 2.1 --- Introduction --- p.7 / Chapter 2.2 --- Development of Long-Range Forecasting Technique --- p.8 / Chapter 2.3 --- Available Techniques of Long-Range Forecast --- p.9 / Chapter 2.3.1 --- Analogs and persistence --- p.10 / Chapter 2.3.2 --- Statistical modelling --- p.12 / Chapter 2.3.3 --- Atmosphere-ocean interaction --- p.17 / Chapter 2.3.4 --- Cycles and time series --- p.18 / Chapter 2.3.5 --- Numerical modelling --- p.19 / Chapter 2.4 --- Rainfall Prediction in Hong Kong --- p.21 / Chapter III --- RAINFALL OF HONG KONG --- p.24 / Chapter 3.1 --- Climatic Feature --- p.24 / Chapter 3.2 --- The Causes of Hong Kong Rainfall --- p.26 / Chapter 3.2.1 --- Tropical cyclone --- p.26 / Chapter 3.2.2 --- Trough or front --- p.28 / Chapter IV --- METHODOLOGY --- p.31 / Chapter 4.1 --- Introduction --- p.31 / Chapter 4.2 --- Empirical Orthogonal Function (EOF) Analysis --- p.32 / Chapter 4.2.1 --- What's EOF --- p.32 / Chapter 4.2.2 --- Why use EOF --- p.34 / Chapter 4.3 --- Discriminant Analysis --- p.36 / Chapter 4.4 --- Data Base --- p.37 / Chapter 4.5 --- Computation Procedures --- p.40 / Chapter 4.6 --- Analysis of Forecast Capability --- p.44 / Chapter V --- THE RESULT AND ANALYSIS OF PREDICTION MODEL --- p.48 / Chapter 5.1 --- The result of EOF analysis --- p.48 / Chapter 5.1.1 --- Extraction of eigenvectors and eigenvalues --- p.48 / Chapter 5.1.2 --- Spatial and Temporal variation of eigenvector pattern --- p.52 / Chapter 5.2 --- Accuracy of the prediction model --- p.53 / Chapter 5.2.1 --- Introduction --- p.53 / Chapter 5.2.2 --- The forecast accuracy from each month --- p.54 / Chapter 5.2.2.1 --- The forecast accuracy made by October --- p.54 / Chapter 5.2.2.2 --- The forecast accuracy made by November --- p.56 / Chapter 5.2.2.3 --- The forecast accuracy made by December --- p.58 / Chapter 5.2.2.4 --- The forecast accuracy made by January --- p.58 / Chapter 5.2.2.5 --- The forecast accuracy made by February --- p.61 / Chapter 5.2.2.6 --- The forecast accuracy made by March --- p.61 / Chapter 5.2.2.7 --- The forecast accuracy made by April --- p.64 / Chapter 5.2.3 --- Optimal length of dependent data --- p.64 / Chapter 5.2.4 --- Analysis the prediction results --- p.67 / Chapter 5.2.5 --- Comparison between the method used in this study with those methods adopted by ROHK --- p.69 / Chapter 5.2.5.1 --- Introduction --- p.69 / Chapter 5.2.5.2 --- Comparison of the forecast accuracy between two studies --- p.70 / Chapter VI --- CONCLUSION --- p.73 / Chapter 6.1 --- Summary of Findings --- p.73 / Chapter 6.2 --- Limitations of the Research --- p.75 / Chapter 6.3 --- Prospects of the Research --- p.76 / APPENDICES --- p.78 / LIST OF CITED REFERENCES --- p.92 / LIST OF READING MATERIALS --- p.97

Ces dernières années, les contenus vidéos ont évolué très rapidement. En effet, les télévisions (TV) ont rapidement évolué vers l’Ultra Haute résolution (UHD), la Haute Fréquence d’images (HFR) ou la stéréoscopie (3D). La tendance actuelle est à l’imagerie à Haute Dynamique de luminance (HDR). Ces technologies permettent de reproduire des images beaucoup plus lumineuses que celles des écrans actuels. Chacune de ces améliorations représente une augmentation du coût de stockage et nécessite la création de nouveaux standards de compression vidéo, toujours plus performant. La majorité des consommateurs est actuellement équipé de TV ayant une Dynamique Standard (SDR) qui ne supportent pas les contenus HDR et ils vont lentement renouveler leurs écrans pour un HDR. Il est donc important de délivrer un signal HDR qui puisse être décodé par ces deux types d’écrans. Cette rétro compatibilité est rendue possible par un outil appelé TMO (Tone Mapping Operator) qui transforme un contenu HDR en une version SDR. Au travers de cette thèse, nous explorons de nouvelles méthodes pour améliorer la compression HDR rétro compatible. Premièrement, nous concevons un TMO qui optimise les performances d’un schéma de compression scalable où une couche de base et d’amélioration sont envoyées pour reconstruire les contenus HDR et SDR. Il est démontré que le TMO optimal dépend seulement de la couche SDR de base et que le problème de minimisation peut être séparé en deux étapes consécutives. Pour ces raisons, nous proposons ensuite un autre TMO conçu pour optimiser les performances d’un schéma de compression utilisant uniquement une couche de base mais avec un modèle amélioré et plus précis. Ces deux travaux optimisent des TMO pour images fixes. Par la suite, la thèse se concentre sur l’optimisation de TMO spécifiques à la vidéo. Cependant, on y démontre que l’utilisation d’une prédiction pondérée pour la compression SDR est aussi bon voir meilleur que d’utiliser un TMO optimisé temporellement. Pour ces raisons, un nouvel algorithme et de nouveaux modes de prédictions pondérées sont proposés pour gérer plus efficacement la large diversité des changements lumineux dans les séquences vidéos. / In recent years, video content evolved very quickly. Indeed, televisions (TV) quickly evolved to Ultra High Definition (UHD), High Frame Rate (HFR) or stereoscopy (3D). The recent trend is towards High Dynamic range (HDR). These new technologies allow the reproduction of much brighter images than for actual displays. Each of these improvements represents an increase in storage cost and therefore requires the creation of new video compression standards, always more efficient. The majority of consumers are currently equipped with Standard Dynamic Range (SDR) displays, that cannot handle HDR content. Consumers will slowly renew their display to an HDR one and it is therefore of great importance to deliver an HDR signal that can be decoded by both SDR and HDR displays. Such backward compatibility is provided by a tool called Tone Mapping Operator (TMO) which transforms an HDR content into an SDR version. In this thesis, we explore new methods to improve the backward compatible HDR compression. First, we design a Tone Mapping to optimize scalable compression scheme performances where a base and an enhancement layer are sent to reconstruct the SDR and HDR content. It is demonstrated that the optimum TMO only depends on the SDR base layer and that the minimization problem can be separated in two consecutive minimization steps. Based on these observations, we then propose another TMO designed to optimize the performances of compression schemes using only a base layer but with an enhanced and more precise model. Both of these works optimize TMO for still images. Thereafter, this thesis focuses on the optimization of video-specific TMO. However, we demonstrate that using a weighted prediction for the SDR compression is as good or even better than using a temporally optimized TMO. Therefore, we proposed a new weighted prediction algorithm and new weighted prediction modes to handle more efficiently the large diversity of brightness variations in video sequences.

Monitoring wildlife habitats has become important to forest ecosystem management because it provides valuable information about the response of forests and their species to harvest practices, impacts from recreational use, conservation efforts, and natural and human-caused disturbances. Monitoring is a complex task that requires a variety of abiotic and biotic measurements and decisions about what should be measured, and when and where measurements should be taken. Riparian habitats contain unusually high diversity and are important to land managers. Wildlife assessments of riparian areas have focused on vertebrate species such as amphibians, birds, and mammals, but have largely ignored the arthropod components of the habitats. Arthropods constitute over 85% of all species and posses characteristics that make them valuable for tracking environmental changes. The purpose of this study was to gather site-specific data about epigaeic, riparian beetle community composition of the H.J. Andrews Experimental Forest (HJA). The patterns of beetle distribution, abundance, and diversity were analyzed and the results were used to characterize and compare the riparian and adjacent upslope beetle communities. Almost 8,000 beetle specimens representing about 250 species were collected from 141 pitfall traps placed along 10 transects in 3 different channel morphologies along Lookout Creek in the HJA. Traps were opened during six 30-day sampling periods over 2 years. Riparian and adjacent upslope beetle communities had high diversity measurements. The average difference of the calculated Simpson's Diversity Index between the two communities was 0.0116 and represented about 1% of the average riparian diversity. Analysis of species-curves indicated that the riparian habitats contained a higher total number of species. Multivariate Principal Coordinate Analysis indicated that the two habitats had distinctly different beetle communities. Multigroup Discriminant Analysis correctly classified 89.7% of the sampling units as the habitat group into which they were assigned a priori. Detailed recommendations for monitoring riparian habitats were discussed. / Graduation date: 2000

This study describes the composition of forest landscapes surrounding northern spotted owl (Strix occidentalis caurina) nests in the central Cascade Mountains of Oregon. I compared forest composition around 126 owl nests in 70 pair territories with forest composition around 119 points drawn randomly from all terrestrial cover-types, and around 104 points drawn randomly from the old-forest (closed canopy, > 80 yrs) cover type. All nest sites and random points were drawn from U.S. Forest Service lands and were not drawn from privately owned lands or Wilderness Areas. Forest cover was classified on a Landsat Thematic Mapper image. I quantified the percentage of old-forest within 200 concentric circular plots (0.04-5.0-km radii), centered on each analyzed point, using a geographic information system. I used logistic regression to make spatially-explicit inferences. Owl nests were surrounded by more old-forest when compared to points drawn randomly from all terrestrial cover types: there was significantly (P<0.05) more old-forest around the owl nests in plots as large as 1.79 km in radius. When compared to points drawn randomly from the old-forest cover type, owl nests were surrounded by significantly (P<0.05) more old-forest in plots with 0.17-0.80-km radii. Exploratory analyses suggest that the landscape scales most pertinent to northern spotted owl nest site positioning in this study area appear to be (in descending order): the surrounding 10-15 ha (~200-m radius), the surrounding 25-30 ha (~300-m radius), the surrounding 200 ha (800-m radius), and possibly the surrounding 700 ha (1,500-m radius). This study supports the assertion that northern spotted owls are strongly associated with older forests. The results also indicate that owl nests are most associated with higher proportions of old-forest near the nest implying that the arrangement of habitat is important for nest-site selection/positioning Since spotted owls in the central Cascade Mountains of Oregon are known to have home-ranges that average 1,769 ha, it is important to recognize that these results apply to nest-site selection/positioning on the landscape and not to the amount of habitat necessary for pair persistence or successful reproduction. / Graduation date: 1998