931 resultados para Antennas For Satellite Broadcasting
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Menestyäkseen nykymaailmassa ihmiset ovat turvautuneet toisiinsa muodostaen samallaerilaisia yhteisöjä ja verkostoja. Näille yhteisöille on tunnusomaista, että niissä vaikuttavien jäsenien ajatustavat yhtyvät keskenään. Yhteisöissä syntyy uusia ideoita ja keksintöjä. Niiden välittäminen maailmalle on usein kuitenkin ongelmallista. Digitaalisuus, Internet ja monet muut uudet teknologiat tuovat yhden ratkaisun ongelmaan. Eräs uuden teknologian mahdollistama kanava on yhteisötelevisio, jonka kautta yhteisön viestintää voidaan tehokkaasti välittää. Yhteisöilläei kuitenkaan ole teknistä taitoa toteuttaa tällaista palvelua. Yhteisöille, kuten pk-yrityksille, kouluille, seuroille, yhdistyksille ja jopa yksittäisille ihmisille, tuleekin pystyä tarjoamaan valmis konsepti, joka on helposti heidän käytettävissään. Tämä diplomityö toimii teknisenä pohjana Finnish Satellite Television Oy:n yhteisö-tv -palvelukonseptille, joka tullaan ottamaan laajamittaiseen käyttöön vuoden 2007 aikana. Työssä käydään läpi yhteisön ja yhteisöllisyyden tunnusmerkit ja peruspiirteet, luodaan katsaus yhteisötelevision alkutaipaleisiin, nykytilaan ja sen eri ratkaisuihin. Lisäksi tutustutaan yhteisö-tv:n kansainvälisiin ja kotimaisiin kokeiluihin ja pilottiprojekteihin. Työn teknisessä osassa tutkitaan yhteisötelevision mahdollistaviin teknologioihin, siirtoteihin sekä digitaalisiin tuotantojärjestelmiin. Lopuksi työssä kootaan yhteen käytettävyydeltään, liikutettavuudeltaan ja kustannustehokkuudeltaan sopivimmat tekniset toteutusvaihtoehdot konseptin käyttöönottoa varten.
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This project proposes a preliminary architectural design for a control and data processing center, also known as 'ground segment', for Earth observation satellites.
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Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) is a ubiquitously expressed gene with higher levels observed in skeletal muscle. Recently, our laboratory showed (Bonala S, Lokireddy S, Arigela H, Teng S, Wahli W, Sharma M, McFarlane C, Kambadur R. J Biol Chem 287: 12935-12951, 2012) that PPARβ/δ modulates myostatin activity to induce myogenesis in skeletal muscle. In the present study, we show that PPARβ/δ-null mice display reduced body weight, skeletal muscle weight, and myofiber atrophy during postnatal development. In addition, a significant reduction in satellite cell number was observed in PPARβ/δ-null mice, suggesting a role for PPARβ/δ in muscle regeneration. To investigate this, tibialis anterior muscles were injured with notexin, and muscle regeneration was monitored on days 3, 5, 7, and 28 postinjury. Immunohistochemical analysis revealed an increased inflammatory response and reduced myoblast proliferation in regenerating muscle from PPARβ/δ-null mice. Histological analysis confirmed that the regenerated muscle fibers of PPARβ/δ-null mice maintained an atrophy phenotype with reduced numbers of centrally placed nuclei. Even though satellite cell numbers were reduced before injury, satellite cell self-renewal was found to be unaffected in PPARβ/δ-null mice after regeneration. Previously, our laboratory had showed (Bonala S, Lokireddy S, Arigela H, Teng S, Wahli W, Sharma M, McFarlane C, Kambadur R. J Biol Chem 287: 12935-12951, 2012) that inactivation of PPARβ/δ increases myostatin signaling and inhibits myogenesis. Our results here indeed confirm that inactivation of myostatin signaling rescues the atrophy phenotype and improves muscle fiber cross-sectional area in both uninjured and regenerated tibialis anterior muscle from PPARβ/δ-null mice. Taken together, these data suggest that absence of PPARβ/δ leads to loss of satellite cells, impaired skeletal muscle regeneration, and postnatal myogenesis. Furthermore, our results also demonstrate that functional antagonism of myostatin has utility in rescuing these effects.
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The subject of the thesis was the digital audio broadcasting technology developed in the Eureka project 147. The research was based on the literature on the subject. At first, some reasons for the digitisation of broadcasting technology were given. Next, the channel multiplexing and channel coding methods employed by digital radio were discussed. The design of these methods is based on certain phenomena related to the propagation of radio-frequency signals, and these phenomena were also described. After that, audio and data transfer mechanisms as well as the structure of digital radio network were explained. Furthermore, digital audio and data services were considered. Finally, the digital radio was examined from marketing and administrative aspects. From a merely technical point of view, the digital radio technology offers several improvements in comparison with analogue technology. However, the digital radio has not become as widespread as it was perhaps originally expected during its development.
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This thesis considers aspects related to the design and standardisation of transmission systems for wireless broadcasting, comprising terrestrial and mobile reception. The purpose is to identify which factors influence the technical decisions and what issues could be better considered in the design process in order to assess different use cases, service scenarios and end-user quality. Further, the necessity of cross-layer optimisation for efficient data transmission is emphasised and means to take this into consideration are suggested. The work is mainly related terrestrial and mobile digital video broadcasting systems but many of the findings can be generalised also to other transmission systems and design processes. The work has led to three main conclusions. First, it is discovered that there are no sufficiently accurate error criteria for measuring the subjective perceived audiovisual quality that could be utilised in transmission system design. Means for designing new error criteria for mobile TV (television) services are suggested and similar work related to other services is recommended. Second, it is suggested that in addition to commercial requirements there should be technical requirements setting the frame work for the design process of a new transmission system. The technical requirements should include the assessed reception conditions, technical quality of service and service functionalities. Reception conditions comprise radio channel models, receiver types and antenna types. Technical quality of service consists of bandwidth, timeliness and reliability. Of these, the thesis focuses on radio channel models and errorcriteria (reliability) as two of the most important design challenges and provides means to optimise transmission parameters based on these. Third, the thesis argues that the most favourable development for wireless broadcasting would be a single system suitable for all scenarios of wireless broadcasting. It is claimed that there are no major technical obstacles to achieve this and that the recently published second generation digital terrestrial television broadcasting system provides a good basis. The challenges and opportunities of a universal wireless broadcasting system are discussed mainly from technical but briefly also from commercial and regulatory aspect
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In this work we study the classification of forest types using mathematics based image analysis on satellite data. We are interested in improving classification of forest segments when a combination of information from two or more different satellites is used. The experimental part is based on real satellite data originating from Canada. This thesis gives summary of the mathematics basics of the image analysis and supervised learning , methods that are used in the classification algorithm. Three data sets and four feature sets were investigated in this thesis. The considered feature sets were 1) histograms (quantiles) 2) variance 3) skewness and 4) kurtosis. Good overall performances were achieved when a combination of ASTERBAND and RADARSAT2 data sets was used.
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The present study investigates the spatial and spectral discrimination potential for grassland patches in the inner Turku Archipelago using Landsat Thematic Mapper satellite imagery. The spatial discrimination potential was computed through overlay analysis using official grassland parcel data and a hypothetical 30 m resolution satellite image capturing the site. It found that Landsat TM imagery’s ability to retrieve pure or near-pure pixels (90% purity or more) from grassland patches smaller than 1 hectare was limited to 13% success, compared to 52% success when upscaling the resolution to 10 x 10 m pixel size. Additionally, the perimeter/area patch metric is proposed as a predictor for the suitability of the spatial resolution of input imagery. Regression analysis showed that there is a strong negative correlation between a patch’s perimeter/area ratio and its pure pixel potential. The study goes on to characterise the spectral response and discrimination potential for the five main grassland types occurring in the study area: recreational grassland, traditional pasture, modern pasture, fodder production grassland and overgrown grassland. This was done through the construction of spectral response curves, a coincident spectral plot and a contingency matrix as well as by calculating the transformed divergence for the spectral signatures, all based on training samples from the TM imagery. Substantial differences in spectral discrimination potential between imagery from the beginning of the growing season and the middle of summer were found. This is because the spectral responses for these five grassland types converge as the peak of the growing season draws nearer. Recreational grassland shows a consistent discrimination advantage over other grassland types, whereas modern pasture is most easily confused. Traditional pasture land, perhaps the most biologically valuable grassland type, can be spectrally discriminated from other grassland types with satisfactory success rates provided early growing season imagery is used.
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Konsistens och förändring i finländsk etermediapolitik. Implementering av digital television och en jämförelse med Kanada Avhandlingen handlar om hur det finländska televisionssystemet förändrades i slutet av 1990-talet från en nationell institution till ett dualistiskt system som präglas av stark marknadsorientering. Syftet med avhandlingen är att förstå på vilket sätt en så snabb förändring kunde ske och analysera de institutionella faktorerna bakom utvecklingen. På teoretisk nivå diskuteras tesen om det nära sambandet mellan statliga politiska institutioner och rundradioverksamhetens institutioner. Avhandlingen består av två fallstudier. Den första sätter fokus på de första åren av den finländska televisionens digitaliseringsprocess som startade med starka industriell-nationalistiska motiveringar. Analysen, som baserar på offentliga dokument, sträcker sig framtill hösten 2001 då de digitala televisionssändningarna startade och regeringspropositionen om den nya kommunikationsmarknadslagen lämnades till riksdagen. Dessa policy-processer analyseras som en ”marknadisering” av de traditionella styrningsprinciper och idéer gällande finländsk rundradioverksamheten. En jämförelse mellan Finlands och Kanadas nationella rundradiopolitik gör att man kan koppla slutsatserna till den internationella utvecklingen. Jämförelsen visar hur kommunikationspolitiska linjen i de två länderna har kommit att likna varandra trots att ländernas tv-system och deras styrordningar är mycket olika. Exemplet med Kanada visar att den särskilda teknologin inte är viktig utan snarare de kommersiella intressen som står bakom och som beslutsfattare gärna döljer i en nationalistisk retorik. Studien visar att det är viktigt att beakta vilken tyngd man i politiken ger de två sidor som rundradioverksamheten består av: sändningsteknologin och verksamheten som en speciell kulturform. Nationalstatens handlingsutrymme minskar inom fältet om målet är att vara framgångsrik i konkurrensen i den nya internationella ekonomin. Enligt de nyliberalistiska principer som det politiska systemet överlag har tillägnat sig det är önskvärd men också helt inhemska institutionella traditioner och praxis som följdes i den finländska digitaliseringsprocessen främjade utvecklingen som ledde till att nästan alla ursprungliga nationella syften föll sönder.
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Medium-resolution satellite images have been widely used for the identification and quantification of irrigated areas by center pivot. These areas, which present predominantly circular forms, can be easily identified by visual analyses of these images. In addition to identifying and quantifying areas irrigated by center pivot, other information that is associated to these areas is fundamental for producing cadastral maps. The goal of this work was to generate cadastral mapping of areas irrigated by center pivots in the State of Minas Gerais, Brazil, with the purpose of supplying information on irrigated agriculture. Using the satellite CBERS2B/CCD, images were used to identify and quantify irrigated areas and then associate these areas with a database containing information about: irrigated area, perimeter, municipality, path row, basin in which the pivot is located, and the date of image acquisition.3,781 center pivots systems were identified. The smallest area irrigated was 4.6 hectares and the largest one was 192.6 hectares. The total estimated value of irrigated area was 254,875 hectares. The largest number of center pivots appeared in the municipalities of Unaí and Paracatu, with 495 and 459 systems, respectively. Cadastral mapping is a very useful tool to assist and enhance information on irrigated agriculture in the State of Minas Gerais.
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There has been interest in reducing the use of herbicides for weed control in order to decrease environmental degradation problems. The objective of this study was to evaluate the effects of gliricidia planting density sown by broadcasting and intercopping on green ear and corn grain yield as well as on weed control. A randomized block design with split-plots and five replicates were adopted. Cultivars AG 1051, BM 2022, and BM 3061, assigned to plots, were submitted to the following treatments: no hoeing, two hoeings (at 20 and 40 days after sowing), and intercropped with gliricidia sown at densities of 10 and 20 seeds m-2. Thirty weed species occurred in the experiment area, with Cucumis anguria as the most frequent ones. Cultivar BM 2022 was the best for the total number of ears (TNE) and number (NMHE) and weight of marketable husked ears. Together with cultivar AG 1051, this cultivar had the highest total weight and marketable unhusked ear weight (MUEW). However, the cultivars did not differ with respect to grain yield (GY). The highest green ear and corn grain yield and weed control percentages were obtained with two hoeings; in MUEW, NMHE and GY, intercropping provided intermediate means in comparison with those obtained in hoed and non-hoed plots, indicating that gliricidia was partially beneficial to corn. Increased gliricidia seeding density heightened the benefits to corn (TNE and MUEW). The lack of hoeing produced the poorest green ear and grain yields.
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It has been shown for several DNA probes that the recently introduced Fast-FISH (fluorescence in situ hybridization) technique is well suited for quantitative microscopy. For highly repetitive DNA probes the hybridization (renaturation) time and the number of subsequent washing steps were reduced considerably by omitting denaturing chemical agents (e.g., formamide). The appropriate hybridization temperature and time allow a clear discrimination between major and minor binding sites by quantitative fluorescence microscopy. The well-defined physical conditions for hybridization permit automatization of the procedure, e.g., by a programmable thermal cycler. Here, we present optimized conditions for a commercially available X-specific a-satellite probe. Highly fluorescent major binding sites were obtained for 74oC hybridization temperature and 60 min hybridization time. They were clearly discriminated from some low fluorescent minor binding sites on metaphase chromosomes as well as in interphase cell nuclei. On average, a total of 3.43 ± 1.59 binding sites were measured in metaphase spreads, and 2.69 ± 1.00 in interphase nuclei. Microwave activation for denaturation and hybridization was tested to accelerate the procedure. The slides with the target material and the hybridization buffer were placed in a standard microwave oven. After denaturation for 20 s at 900 W, hybridization was performed for 4 min at 90 W. The suitability of a microwave oven for Fast-FISH was confirmed by the application to a chromosome 1-specific a-satellite probe. In this case, denaturation was performed at 630 W for 60 s and hybridization at 90 W for 5 min. In all cases, the results were analyzed quantitatively and compared to the results obtained by Fast-FISH. The major binding sites were clearly discriminated by their brightness
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This doctoral dissertation explores the intra-organizational dynamics of a strategic renewal process. The main research question is how the pursuit of change and organizational inertia co-exist, intertwine, and collide in organizational cognition and capabilities during the strategic renewal. It is a comprehensive study on how organizational capabilities, organizational cognition, and structure enhance and inhibit change. Theoretically, the study is positioned in the modern tradition of strategy research, using the dynamic capability view and the organizational and managerial cognition research tradition as the main theoretical frames. Empirically, the study is a longitudinal case study of the Finnish Broadcasting Company (Yle), following the organizational changes during the years of 2011-1014. The analysis is based on both quantitative and qualitative data, which was collected during the research process using surveys, interviews, and archives. The main theoretical contribution is the application of the two theoretical approaches in one study. Empirically, the study contributes to operationalization of the concepts related to the dynamic capability view and organizational cognition, in a media context that is going through drastic changes due to digitalization. Furthermore, the case of a public broadcasting company extends the application of the theoretical concepts to the context of public management. The results suggest that renewal is a complex process, in which an organization’s perceptions intertwine with the strategic actions and decision-making. The change evolves pathdependently: the past experiences, routines, and organizational structures tend to dictate the future visions, desires, and actions. The study also reveals how the public nature of an organization adds to the tensions between change and organizational inertia, and hampers the decision-making. The doctoral dissertation consists of six research papers, each of which explores the phenomenon under study from a different perspective.
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In this Master Thesis the characteristics of the chosen fractal microstrip antennas are investigated. For modeling has been used the structure of the square Serpinsky fractal curves. During the elaboration of this Master thesis the following steps were undertaken: 1) calculation and simulation of square microstrip antennа, 2) optimizing for obtaining the required characteristics on the frequency 2.5 GHz, 3) simulation and calculation of the second and third iteration of the Serpinsky fractal curves, 4) radiation patterns and intensity distribution of these antennas. In this Master’s Thesis the search for the optimal position of the port and fractal elements was conducted. These structures can be used in perspective for creation of antennas working at the same time in different frequency range.