863 resultados para User perceived video quality on mobile devices
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Journal of Hydraulic Engineering, Vol. 135, No. 11, November 1, 2009
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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.
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O campo dos media na Finlândia encontra-se num processo de mudanças aparentemente imparáveis, com os dispositivos móveis, tal como os smartphones e tablets, a influenciarem cada vez mais os padrões de produção e consumo de media. Nesta dissertação é defendido que esta situação é influenciada por factores históricos, sociais e culturais: desde os livros e jornais como meio de manter a língua finlandesa até aos benefícios da Segurança Social que permitiram que até as pessoas com menos rendimentos comprassem o jornal para se manterem a par dos desenvolvimentos do país, bem como a grande tradição de leitura que é associada aos finlandeses, assim como as condições que ao longo da história fazem fizeram com que os finlandeses sejam fascinados pelas novas tecnologias. Adicionalmente, presto especial atenção às estratégias que são adoptadas pelas cada vez mais convergentes companhias de media para enfrentarem a competição de elementos como os social media.
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Novel input modalities such as touch, tangibles or gestures try to exploit human's innate skills rather than imposing new learning processes. However, despite the recent boom of different natural interaction paradigms, it hasn't been systematically evaluated how these interfaces influence a user's performance or whether each interface could be more or less appropriate when it comes to: 1) different age groups; and 2) different basic operations, as data selection, insertion or manipulation. This work presents the first step of an exploratory evaluation about whether or not the users' performance is indeed influenced by the different interfaces. The key point is to understand how different interaction paradigms affect specific target-audiences (children, adults and older adults) when dealing with a selection task. 60 participants took part in this study to assess how different interfaces may influence the interaction of specific groups of users with regard to their age. Four input modalities were used to perform a selection task and the methodology was based on usability testing (speed, accuracy and user preference). The study suggests a statistically significant difference between mean selection times for each group of users, and also raises new issues regarding the “old” mouse input versus the “new” input modalities.
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Magdeburg, Univ., Fak. für Informatik, Diss., 2015
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When two candidates of different quality compete in a one dimensional policy space, the equilibrium outcomes are asymmetric and do not correspond to the median. There are three main effects. First, the better candidate adopts more centrist policies than the worse candidate. Second, the equilibrium is statistical, in the sense that it predicts a probability distribution of outcomes rather than a single degenerate outcome. Third, the equilibrium varies systematically with the level of uncertainty about the location of the median voter. We test these three predictions using laboratory experiments, and find strong support for all three. We also observe some biases and show that they canbe explained by quantal response equilibrium.
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Developing countries face serious problems on building and using digital libraries (DL) due to low computer and Internet penetration rates, lack of financial resources, etc. Thus, since mobile phones are much more used than computers in these countries, they might be a good alternative for accessing DL. Moreover, in the developed world there has been an exponential growth on the usage of mobile phones for data traffic, establishing a good ground for accessing DL on mobile devices. This paper presents a design proposal for making DSpace-based digital libraries accessible on mobile phones. Since DSpace is a popular free and open source DL system used around the world, making it accessible through mobile devices might contribute for improving the global accessibility of scientific and academic publications.
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Abstract This PhD thesis addresses the issue of alleviating the burden of developing ad hoc applications. Such applications have the particularity of running on mobile devices, communicating in a peer-to-peer manner and implement some proximity-based semantics. A typical example of such application can be a radar application where users see their avatar as well as the avatars of their friends on a map on their mobile phone. Such application become increasingly popular with the advent of the latest generation of mobile smart phones with their impressive computational power, their peer-to-peer communication capabilities and their location detection technology. Unfortunately, the existing programming support for such applications is limited, hence the need to address this issue in order to alleviate their development burden. This thesis specifically tackles this problem by providing several tools for application development support. First, it provides the location-based publish/subscribe service (LPSS), a communication abstraction, which elegantly captures recurrent communication issues and thus allows to dramatically reduce the code complexity. LPSS is implemented in a modular manner in order to be able to target two different network architectures. One pragmatic implementation is aimed at mainstream infrastructure-based mobile networks, where mobile devices can communicate through fixed antennas. The other fully decentralized implementation targets emerging mobile ad hoc networks (MANETs), where no fixed infrastructure is available and communication can only occur in a peer-to-peer fashion. For each of these architectures, various implementation strategies tailored for different application scenarios that can be parametrized at deployment time. Second, this thesis provides two location-based message diffusion protocols, namely 6Shot broadcast and 6Shot multicast, specifically aimed at MANETs and fine tuned to be used as building blocks for LPSS. Finally this thesis proposes Phomo, a phone motion testing tool that allows to test proximity semantics of ad hoc applications without having to move around with mobile devices. These different developing support tools have been packaged in a coherent middleware framework called Pervaho.
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Actualment un típic embedded system (ex. telèfon mòbil) requereix alta qualitat per portar a terme tasques com codificar/descodificar a temps real; han de consumir poc energia per funcionar hores o dies utilitzant bateries lleugeres; han de ser el suficientment flexibles per integrar múltiples aplicacions i estàndards en un sol aparell; han de ser dissenyats i verificats en un període de temps curt tot i l’augment de la complexitat. Els dissenyadors lluiten contra aquestes adversitats, que demanen noves innovacions en arquitectures i metodologies de disseny. Coarse-grained reconfigurable architectures (CGRAs) estan emergent com a candidats potencials per superar totes aquestes dificultats. Diferents tipus d’arquitectures han estat presentades en els últims anys. L’alta granularitat redueix molt el retard, l’àrea, el consum i el temps de configuració comparant amb les FPGAs. D’altra banda, en comparació amb els tradicionals processadors coarse-grained programables, els alts recursos computacionals els permet d’assolir un alt nivell de paral•lelisme i eficiència. No obstant, els CGRAs existents no estant sent aplicats principalment per les grans dificultats en la programació per arquitectures complexes. ADRES és una nova CGRA dissenyada per I’Interuniversity Micro-Electronics Center (IMEC). Combina un processador very-long instruction word (VLIW) i un coarse-grained array per tenir dues opcions diferents en un mateix dispositiu físic. Entre els seus avantatges destaquen l’alta qualitat, poca redundància en les comunicacions i la facilitat de programació. Finalment ADRES és un patró enlloc d’una arquitectura concreta. Amb l’ajuda del compilador DRESC (Dynamically Reconfigurable Embedded System Compile), és possible trobar millors arquitectures o arquitectures específiques segons l’aplicació. Aquest treball presenta la implementació d’un codificador MPEG-4 per l’ADRES. Mostra l’evolució del codi per obtenir una bona implementació per una arquitectura donada. També es presenten les característiques principals d’ADRES i el seu compilador (DRESC). Els objectius són de reduir al màxim el nombre de cicles (temps) per implementar el codificador de MPEG-4 i veure les diferents dificultats de treballar en l’entorn ADRES. Els resultats mostren que els cícles es redueixen en un 67% comparant el codi inicial i final en el mode VLIW i un 84% comparant el codi inicial en VLIW i el final en mode CGA.
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The purpose of this study was to investigate the effect of cement paste quality on the concrete performance, particularly fresh properties, by changing the water-to-cementitious materials ratio (w/cm), type and dosage of supplementary cementitious materials (SCM), and airvoid system in binary and ternary mixtures. In this experimental program, a total matrix of 54 mixtures with w/cm of 0.40 and 0.45; target air content of 2%, 4%, and 8%; a fixed cementitious content of 600 pounds per cubic yard (pcy), and the incorporation of three types of SCMs at different dosages was prepared. The fine aggregate-to- total aggregate ratio was fixed at 0.42. Workability, rheology, air-void system, setting time, strength, Wenner Probe surface resistivity, and shrinkage were determined. The effects of paste variables on workability are more marked at the higher w/cm. The compressive strength is strongly influenced by the paste quality, dominated by w/cm and air content. Surface resistivity is improved by inclusion of Class F fly ash and slag cement, especially at later ages. Ternary mixtures performed in accordance with their ingredients. The data collected will be used to develop models that will be part of an innovative mix proportioning procedure.
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OBJECTIVE: Imaging during a period of minimal myocardial motion is of paramount importance for coronary MR angiography (MRA). The objective of our study was to evaluate the utility of FREEZE, a custom-built automated tool for the identification of the period of minimal myocardial motion, in both a moving phantom at 1.5 T and 10 healthy adults (nine men, one woman; mean age, 24.9 years; age range, 21-32 years) at 3 T. CONCLUSION: Quantitative analysis of the moving phantom showed that dimension measurements approached those obtained in the static phantom when using FREEZE. In vitro, vessel sharpness, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were significantly improved when coronary MRA was performed during the software-prescribed period of minimal myocardial motion (p < 0.05). Consistent with these objective findings, image quality assessments by consensus review also improved significantly when using the automated prescription of the period of minimal myocardial motion. The use of FREEZE improves image quality of coronary MRA. Simultaneously, operator dependence can be minimized while the ease of use is improved.
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Networks are evolving toward a ubiquitous model in which heterogeneousdevices are interconnected. Cryptographic algorithms are required for developing securitysolutions that protect network activity. However, the computational and energy limitationsof network devices jeopardize the actual implementation of such mechanisms. In thispaper, we perform a wide analysis on the expenses of launching symmetric and asymmetriccryptographic algorithms, hash chain functions, elliptic curves cryptography and pairingbased cryptography on personal agendas, and compare them with the costs of basic operatingsystem functions. Results show that although cryptographic power costs are high and suchoperations shall be restricted in time, they are not the main limiting factor of the autonomyof a device.
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This study examines the relationship between floral structure and bud quality with the productivity and fruit shape of Gala, Fuji and Daiane apple cultivars under the mild winter conditions in Southern Brazil. Six different types of floral structures were characterized in field growing plants, according to their nature and bud size: spurs, short and long twigs with weak and vigorous buds. Variables related to the phenology and the productivity for these different structures were evaluated. Gala and Fuji cvs. showed earlier phenological development in the twigs, and cv. Daiane in the spurs. For the three cvs. the highest percentage of buds in each phenological phase was observed in the long twigs. The long twigs also showed the highest sprout and fruit set index, floral number per cluster, and leaf area in the three cvs., while the bud abortion was higher in the spurs than in the twigs. No difference was observed among the structures in cvs. Gala and Fuji regarding to the fruit shape. In the cv. Daiane, however, a tendency to higher length diameter ratio of the fruits produced by the long twigs was observed.
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Tulevaisuudessa telekommunikaatioala tulee keskittymään pitkälti langattomiin sovelluksiin ja lisäarvopalveluihin. Tuottaakseen näitä palveluja alan yritykset tekevät yhteistyötä laajan kehittäjäjoukon kanssa. Työn tavoitteena oli parantaa case-yrityksen jo olemassaolevaa toimintamallia, jota se soveltaa yhteistyössään kehittäjien kanssa. Tutkimus keskittyy mobiiliapplikaatiokehittäjiin. Toimintamalli kattaa pääasiassa palvelutarjonnan kehittäjä-allianssissa.Jotta toimintamalliin pystyttäisiin tekemään strategisia muutoksia, oli aluksi tärkeä tunnistaa kehittäjien tarpeet ja toiseksi tarkkailla ja analysoida ympäristöä ja sillä tavoin tunnistaa pääkilpailijat ja heidän tarjontansa mobiiliapplikaatiokehittäjille. Tutkimus toteutettiin suorittamalla postikysely kehittäjille ja toisaalta tekemällä laadullinen tutkimus kilpailijoista. Kilpailutilanteen luonne ja potentiaaliset kilpailijat olivat tunnistettavissa. Parannusehdotukset sisälsivät sekä yleisiä että palvelukohtaisia parannuksia.