930 resultados para Digital video cameras
Resumo:
O surgimento das tecnologias digitais permitiu o desenvolvimento de meios de contato inéditos entre empresas e consumidores, as chamadas novas mídias. Capazes de reconfigurar indústrias como a fonográfica e a do cinema, as novas mídias têm também impacto considerável na indústria da publicidade. O subsídio cruzado entre anunciantes, veículos de massa e consumidores, consolidado ao longo do século XX, se vê fragilizado com a popularização de aparelhos como Digital Video Recorders (DVRs), tablets, consoles de videogames e telefones celulares, dispositivos que transferem aos consumidores o poder de regular sua exposição à publicidade. Nesse novo ambiente, mídias tradicionais e novas mídias competem pela preferência de consumidores e pela verba dos anunciantes. Apesar da necessidade dos anunciantes de aferir e rentabilizar campanhas publicitárias, verificou-se que o investimento em veículos tradicionais vem crescendo, enquanto a audiência entregue diminui. Num panorama de mudanças, no presente estudo procura-se identificar que fatores influenciam o processo de compra de mídias por parte dos anunciantes, observando a percepção deles sobre mídias emergentes e tradicionais, seus benefícios e desafios. Para tanto, foi realizada uma pesquisa exploratória, utilizando uma abordagem qualitativa. Entre junho e julho de 2009, foram realizadas entrevistas em profundidade com os profissionais responsáveis pelas campanhas publicitárias de 15 empresas anunciantes de grande porte, atuantes em diversas indústrias. Ao analisar os dados colhidos em campo à luz da literatura estudada sobre o tema, a pesquisa identificou três fatores com forte influência sobre a definição do mix de mídias dos entrevistados: o uso de métricas inadequadas às mídias emergentes, a dependência dos anunciantes com as agências de publicidade e os veículos de massa e os próprios processos internos dos anunciantes.
Resumo:
This study examines how MPEG-2 Transport Stream, used in DVB-T video transmission, can be reliably and efficiently transferred to remote locations over an MPLS network. All the relevant technologies used in this scenario are also discussed in the study. This study was done for Digita Oy, which is a major radio and television content distributor in Finland. The theoretical part of the study begins with the introduction to MPLS technology and continues with explanation of IP Multicast and its components. The fourth section discusses MPEG-2 and the formation and content of MPEG-2 Transport Stream. These technologies were studied in relevant literature and RFC documentation. After the theoretical part of the study, the test setup and the test cases are presented. The results of the test cases, and the conclusions that can be drawn based on them, are discussed in the last section of the study. The tests showed that it is possible to transfer digital video quite reliably over an MPLS network using IP Multicast. By configuring the equipment correctly, the recovery time of the network in case of a failure can be shortened remarkably. Also, the unwanted effect of other traffic on the critical video traffic can be eliminated by defining the Quality of Service parameters correctly. There are, however, some issues that need to be tested further before this setup can be used in broadcast networks. Reliable operation of IP Multicast and proper error correction are the main subjects for future testing.
Resumo:
A common problem in video surveys in very shallow waters is the presence of strong light fluctuations, due to sun light refraction. Refracted sunlight casts fast moving patterns, which can significantly degrade the quality of the acquired data. Motivated by the growing need to improve the quality of shallow water imagery, we propose a method to remove sunlight patterns in video sequences. The method exploits the fact that video sequences allow several observations of the same area of the sea floor, over time. It is based on computing the image difference between a given reference frame and the temporal median of a registered set of neighboring images. A key observation is that this difference will have two components with separable spectral content. One is related to the illumination field (lower spatial frequencies) and the other to the registration error (higher frequencies). The illumination field, recovered by lowpass filtering, is used to correct the reference image. In addition to removing the sunflickering patterns, an important advantage of the approach is the ability to preserve the sharpness in corrected image, even in the presence of registration inaccuracies. The effectiveness of the method is illustrated in image sets acquired under strong camera motion containing non-rigid benthic structures. The results testify the good performance and generality of the approach
Resumo:
PURPOSE: To examine the effects of the world's most challenging mountain ultra-marathon (Tor des Géants(®) 2012) on the energy cost of three types of locomotion (cycling, level and uphill running) and running kinematics. METHODS: Before (pre-) and immediately after (post-) the competition, a group of ten male experienced ultra-marathon runners performed in random order three submaximal 4-min exercise trials: cycling at a power of 1.5 W kg(-1) body mass; level running at 9 km h(-1) and uphill running at 6 km h(-1) at an inclination of +15 % on a motorized treadmill. Two video cameras recorded running mechanics at different sampling rates. RESULTS: Between pre- and post-, the uphill-running energy cost decreased by 13.8 % (P = 0.004); no change was noted in the energy cost of level running or cycling (NS). There was an increase in contact time (+10.3 %, P = 0.019) and duty factor (+8.1 %, P = 0.001) and a decrease in swing time (-6.4 %, P = 0.008) in the uphill-running condition. CONCLUSION: After this extreme mountain ultra-marathon, the subjects modified only their uphill-running patterns for a more economical step mechanics.
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Uusi EPR-reaktorikonsepti on suunniteltu selviytymään tapauksista, joissa reaktorinsydän sulaa ja sula puhkaisee paineastian. Suojarakennuksen sisälle on suunniteltu alue, jolle sula passiivisesti kerätään, pidätetään ja jäähdytetään. Alueelle laaditaan valurautaelementeistä ns.sydänsieppari, joka tulvitetaan vedellä. Sydänsulan tuottama jälkilämpö siirtyyveteen, mistä se poistetaan suojarakennuksen jälkilämmönpoistojärjestelmän kautta. Suuri osa lämmöstä poistuu sydänsulasta sen yläpuolella olevaan veteen, mutta lämmönsiirron tehostamiseksi myös sydänsiepparin alapuolelle on sijoitettu vedellä täytettävät jäähdytyskanavat. Jotta sydänsiepparin toiminta voitaisiin todentaa, on Lappeenrannan Teknillisellä Yliopistolla rakennettu Volley-koelaitteisto tätä tarkoitusta varten. Koelaitteisto koostuu kahdesta täysimittaisesta valuraudasta tehdystä jäähdytyskanavasta. Sydänsulan tuottamaa jälkilämpöä simuloidaan koelaitteistossa sähkövastuksilla. Tässä työssä kuvataan simulaatioiden suorittaminen ja vertaillaan saatuja arvoja mittaustuloksiin. Työ keskittyy sydänsiepparista jäähdytyskanaviin tapahtuvan lämmönsiirron teoriaan jamekanismeihin. Työssä esitetään kolme erilaista korrelaatiota lämmönsiirtokertoimille allaskiehumisen tapauksessa. Nämä korrelaatiot soveltuvat erityisesti tapauksiin, joissa vain muutamia mittausparametreja on tiedossa. Työn toinen osa onVolley 04 -kokeiden simulointi. Ensin käytettyä simulointitapaa on kelpoistettuvertaamalla tuloksia Volley 04 ja 05 -kokeisiin, joissa koetta voitiin jatkaa tasapainotilaan ja joissa jäähdytteen käyttäytyminen jäähdytyskanavassa on tallennettu myös videokameralla. Näiden simulaatioiden tulokset ovat hyvin samanlaisiakuin mittaustulokset. Korkeammilla lämmitystehoilla kokeissa esiintyi vesi-iskuja, jotka rikkoivat videoinnin mahdollistavia ikkunoita. Tämän johdosta osassa Volley 04 -kokeita ikkunat peitettiin metallilevyillä. Joitakin kokeita jouduttiin keskeyttämään laitteiston suurten lämpöjännitysten johdosta. Tällaisten testien simulaatiot eivät ole yksinkertaisia suorittaa. Veden pinnan korkeudesta ei ole visuaalista havaintoa. Myöskään jäähdytteen tasapainotilanlämpötiloista ei ole tarkkaa tietoa, mutta joitakin oletuksia voidaan tehdä samoilla parametreilla tehtyjen Volley 05 -kokeiden perusteella. Mittaustulokset Volley 04 ja 05 -kokeista, jotka on videoitu ja voitu ajaa tasapainotilaan saakka, antoivat simulaatioiden kanssa hyvin samankaltaisia lämpötilojen arvoja. Keskeytettyjen kokeiden ekstrapolointi tasapainotilaan ei onnistunut kovin hyvin. Kokeet jouduttiin keskeyttämään niin paljon ennen termohydraulista tasapainoa, ettei tasapainotilan reunaehtoja voitu ennustaa. Videonauhoituksen puuttuessa ei veden pinnan korkeudesta saatu lisätietoa. Tuloksista voidaan lähinnä esittää arvioita siitä, mitä suuruusluokkaa mittapisteiden lämpötilat tulevat olemaan. Nämä lämpötilat ovat kuitenkin selvästi alle sydänsiepparissa käytettävän valuraudan sulamislämpötilan. Joten simulaatioiden perusteella voidaan sanoa, etteivät jäähdytyskanavien rakenteet sula, mikäli niissä on pienikin jäähdytevirtaus, eikä useampia kuin muutama vierekkäinen kanava ole täysin kuivana.
Resumo:
The effects of footwear and inclination on running biomechanics over short intervals are well documented. Although recognized that exercise duration can impact running biomechanics, it remains unclear how biomechanics change over time when running in minimalist shoes and on slopes. Our aims were to describe these biomechanical changes during a 50-minute run and compare them to those observed in standard shoes. Thirteen trained recreational male runners ran 50 minutes at 65% of their maximal aerobic velocity on a treadmill, once in minimalist shoes and once in standard shoes, 1 week apart in a random order. The 50-minute trial was divided into 5-minute segments of running at 0%, +5%, and -5% of treadmill incline sequentially. Data were collected using photocells, high-speed video cameras, and plantar-pressure insoles. At 0% incline, runners exhibited reduced leg stiffness and plantar flexion angles at foot strike and lower plantar pressure at the forefoot and toes in minimalist shoes from minute 34 of the protocol onward. However, only reduced plantar pressure at the toes was observed in standard shoes. Overall, similar biomechanical changes with increased exercise time were observed on the uphill and downhill inclines. The results might be due to the unfamiliarity of subjects to running in minimalist shoes.
Resumo:
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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This qualitative narrative inquiry was driven by my desire to further explore my personal discovery that my utilization of educational technologies in teaching and learning environments seemed to heighten a sense of creativity, which in turn increased reflective practice and authenticity in my teaching. A narrative inquiry approach was used as it offered the opportunity to uncover the deeper meanings of authenticity and reflection as participants' personal experiences were coconstructed and reconstructed in relationship with me and in relationship to a social milieu. To gain further insight into this potential phenomenon, I engaged in 2 conversational interviews with 2 other teachers from an Ontario College in a large urban centre who have utilized educational technologies in their teaching and learning communities and I maintained a research journal, constructed during the interview process, to record my own emerging narrative accounts, reflections, insights and further questions. The field texts consisted of transcriptions of the interviews and my reflective journal. Research texts were developed as field texts were listened to multiple times and texts were examined for meanings and themes. The educational technologies that both women focused on in the interview were digital video of children as they play, learn and develop and the use of an audible teacher voice in online courses. The invitation given to students to explore and discover meaning in videos of children as they watched them with the teacher seemed to be a catalyst for authenticity and a sense of synergy in the classroom. The power of the audible teacher voice came through as an essential component in online learning environments to offer students a sense of humanness and connection with the teacher. Relationships in both online and face to face classrooms emerged as a necessary and central component to all teaching and learning communities. The theme of paradox also emerged as participants recognized that educational technologies can be used in ways that enhance creativity, authenticity, reflection and relationships or in ways that hinder these qualities in the teaching and learning community. Knowledge of the common experiences of college educators who utilize educational technologies, specifically digital video of children to educate early childhood educators, might give meaning and insight to inform the practice of other teachers who seek authentic, reflexive practice in the classroom and in on line environments.
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Die vorliegende Arbeit befasst sich mit dem lateralen Auflösungsvermögen in der kurzkohärenten Interferenzmikroskopie. Das 3D-Auflösungsvermögen von Phasenobjekten ist im Gegensatz zu dem von Intensitätsobjekten stark nichtlinear und vom spezifischen Messverfahren abhängig. In diesem Zusammenhang sind systematische Messfehler von entscheidender Bedeutung. Für die kurzkohärente Interferenzmikroskopie ist das Überschwingen an Kanten von besonderem Belang, da sich der Effekt bei der Messung vieler technischer Oberflächen negativ auswirkt. Er entsteht durch die Überlagerung von Interferenzsignalen lateral benachbarter Objektpunkte von unterschiedlichen Höhenniveaus. Es wird an speziell für diesen Zweck entwickelten Messsystemen untersucht in wie weit dieser Effekt physikalisch reduziert werden kann und wie sich dies auf die laterale Auflösung auswirkt. An einem für den Einsatz in einer Nanomessmaschine optimierten Linnik-Interferometer wird die Justage eines solchen Systems erläutert. Der Sensor verfügt über die Option mit NUV-Licht betrieben zu werden, um die laterale Auflösung zu verbessern. Aufgrund des Einsatzzweckes ist der Arbeitsabstand relativ groß, was die laterale Auflösung einschränkt. Mit einem zweiten auf die Untersuchungen in dieser Arbeit optimierten Versuchsaufbau können die physikalischen Grenzen der kurzkohärenten Interferenzmikroskopie praktisch untersucht werden. Zu diesem Zweck ist der Aufbau mit einem Mikrospiegelarray ausgestattet, um hierüber variable konfokale Blenden zu schaffen. Mit diesem System wird erstmalig konfokale Mikroskopie mit Weißlichtinterferometrie kombiniert. Durch die optische Selektion der konfokalen Mikroskopie soll die Ursache für die Überschwinger an Kanten reduziert werden. Eine weitere Möglichkeit der Einflussnahme stellt die optionale Beleuchtung mit polarisiertem Licht dar, wodurch die laterale Auflösung weiter gesteigert werden kann. Zusätzlich kann auch dieser Aufbau mit kurzwelligem blauem Licht betrieben werden, um die laterale Auflösung zu optimieren. Die Messergebnisse, die mit diesen Versuchsaufbauten gemacht wurden, zeigen, dass im Gegensatz zu den in der derzeitigen Normung genutzten Modellen das Übertragungsverhalten in der Weißlichtinterferometrie bei der Messung von Phasenobjekten stark nichtlinear ist. Das laterale Auflösungsvermögen deckt sich je nach Auswerteverfahren recht gut mit dem von klassischen Mikroskopen bei der Wiedergabe von Intensitätsobjekten. Für die Untersuchungen wurde überwiegend ein Auflösungsnormal mit neun unterschiedlichen eindimensionalen Rechteckstrukturen verwendet, die eine Nominalhöhe im kritischen Bereich kleiner der Kohärenzlänge der verwendeten Lichtquelle aufweisen. Die Ergebnisse bestätigen sich aber auch an technischen Messobjekten aus der Praxis wie beispielsweise einer „digital video disc“.
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We investigate whether dimensionality reduction using a latent generative model is beneficial for the task of weakly supervised scene classification. In detail, we are given a set of labeled images of scenes (for example, coast, forest, city, river, etc.), and our objective is to classify a new image into one of these categories. Our approach consists of first discovering latent ";topics"; using probabilistic Latent Semantic Analysis (pLSA), a generative model from the statistical text literature here applied to a bag of visual words representation for each image, and subsequently, training a multiway classifier on the topic distribution vector for each image. We compare this approach to that of representing each image by a bag of visual words vector directly and training a multiway classifier on these vectors. To this end, we introduce a novel vocabulary using dense color SIFT descriptors and then investigate the classification performance under changes in the size of the visual vocabulary, the number of latent topics learned, and the type of discriminative classifier used (k-nearest neighbor or SVM). We achieve superior classification performance to recent publications that have used a bag of visual word representation, in all cases, using the authors' own data sets and testing protocols. We also investigate the gain in adding spatial information. We show applications to image retrieval with relevance feedback and to scene classification in videos
Resumo:
A common problem in video surveys in very shallow waters is the presence of strong light fluctuations, due to sun light refraction. Refracted sunlight casts fast moving patterns, which can significantly degrade the quality of the acquired data. Motivated by the growing need to improve the quality of shallow water imagery, we propose a method to remove sunlight patterns in video sequences. The method exploits the fact that video sequences allow several observations of the same area of the sea floor, over time. It is based on computing the image difference between a given reference frame and the temporal median of a registered set of neighboring images. A key observation is that this difference will have two components with separable spectral content. One is related to the illumination field (lower spatial frequencies) and the other to the registration error (higher frequencies). The illumination field, recovered by lowpass filtering, is used to correct the reference image. In addition to removing the sunflickering patterns, an important advantage of the approach is the ability to preserve the sharpness in corrected image, even in the presence of registration inaccuracies. The effectiveness of the method is illustrated in image sets acquired under strong camera motion containing non-rigid benthic structures. The results testify the good performance and generality of the approach
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This is a set of videos which explore issues associated with the use of digital video. The videos help bring home the observation that 'piracy' is viewed in many different ways by different people depending upon their context, and the prevailing local laws.
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Restrictions in technology have limited past habitat selection studies for many species to the home-range level, as a finer-scale understanding was often not possible. Consequently, these studies may not identify the true mechanism driving habitat selection patterns, which may influence how such results are applied in conservation. We used GPS dataloggers with digital video recorders to identify foraging modes and locations in which endangered Burrowing Owls (Athene cunicularia) captured prey. We measured the coarse and fine-scale characteristics of vegetation at locations in which owls searched for, versus where they caught, vertebrate prey. Most prey items were caught using hover-hunting. Burrowing Owls searched for, and caught, vertebrate prey in all cover types, but were more likely to kill prey in areas with sparse and less dense vegetative cover. Management strategies designed to increase Burrowing Owl foraging success in the Canadian prairies should try to ensure a mosaic of vegetation heights across cover types.
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Carbendazim is highly toxic to earthworms and is used as a standard control substance when running field-based trials of pesticides, but results using carbendazim are highly variable. In the present study, impacts of timing of rainfall events following carbendazim application on earthworms were investigated. Lumbricus terrestris were maintained in soil columns to which carbendazim and then deionized water (a rainfall substitute) were applied. Carbendazim was applied at 4 kg/ha, the rate recommended in pesticide field trials. Three rainfall regimes were investigated: initial and delayed heavy rainfall 24 h and 6 d after carbendazim application, and frequent rainfall every 48 h. Earthworm mortality and movement of carbendazim through the soil was assessed 14 d after carbendazim application. No detectable movement of carbendazim occurred through the soil in any of the treatments or controls. Mortality in the initial heavy and frequent rainfall was significantly higher (approximately 55%) than in the delayed rainfall treatment (approximately 25%). This was due to reduced bioavailability of carbendazim in the latter treatment due to a prolonged period of sorption of carbendazim to soil particles before rainfall events. The impact of carbendazim application on earthworm surface activity was assessed using video cameras. Carbendazim applications significantly reduced surface activity due to avoidance behavior of the earthworms. Surface activity reductions were least in the delayed rainfall treatment due to the reduced bioavailability of the carbendazim. The nature of rainfall events' impacts on the response of earthworms to carbendazim applications, and details of rainfall events preceding and following applications during field trials should be made at a higher level of resolution than is currently practiced according to standard International Organization for Standardization protocols.
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We have studied growth and estimated recruitment of massive coral colonies at three sites, Kaledupa, Hoga and Sampela, separated by about 1.5 km in the Wakatobi Marine National Park, S.E. Sulawesi, Indonesia. There was significantly higher species richness (P<0.05), coral cover (P<0.05) and rugosity (P<0.01) at Kaledupa than at Sampela. A model for coral reef growth has been developed based on a rational polynomial function, where dx/dt is an index of coral growth with time; W is the variable (for example, coral weight, coral length or coral area), up to the power of n in the numerator and m in the denominator; a1……an and b1…bm are constants. The values for n and m represent the degree of the polynomial, and can relate to the morphology of the coral. The model was used to simulate typical coral growth curves, and tested using published data obtained by weighing coral colonies underwater in reefs on the south-west coast of Curaçao [‘Neth. J. Sea Res. 10 (1976) 285’]. The model proved an accurate fit to the data, and parameters were obtained for a number of coral species. Surface area data was obtained on over 1200 massive corals at three different sites in the Wakatobi Marine National Park, S.E. Sulawesi, Indonesia. The year of an individual's recruitment was calculated from knowledge of the growth rate modified by application of the rational polynomial model. The estimated pattern of recruitment was variable, with little numbers of massive corals settling and growing before 1950 at the heavily used site, Sampela, relative to the reef site with little or no human use, Kaledupa, and the intermediate site, Hoga. There was a significantly greater sedimentation rate at Sampela than at either Kaledupa (P<0.0001) or Hoga (P<0.0005). The relative mean abundance of fish families present at the reef crests at the three sites, determined using digital video photography, did not correlate with sedimentation rates, underwater visibility or lack of large non-branching coral colonies. Radial growth rates of three genera of non-branching corals were significantly lower at Sampela than at Kaledupa or at Hoga, and there was a high correlation (r=0.89) between radial growth rates and underwater visibility. Porites spp. was the most abundant coral over all the sites and at all depths followed by Favites (P<0.04) and Favia spp. (P<0.03). Colony ages of Porites corals were significantly lower at the 5 m reef flat on the Sampela reef than at the same depth on both other reefs (P<0.005). At Sampela, only 2.8% of corals on the 5 m reef crest are of a size to have survived from before 1950. The Scleractinian coral community of Sampela is severely impacted by depositing sediments which can lead to the suffocation of corals, whilst also decreasing light penetration resulting in decreased growth and calcification rates. The net loss of material from Sampela, if not checked, could result in the loss of this protective barrier which would be to the detriment of the sublittoral sand flats and hence the Sampela village.