119 resultados para SPECKLE-TRACKING


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The movements, diving behaviour and thermal environment occupied by 4 adult female olive ridley turtles Lepidochelys olivacea in northern Australia were determined through satellite telemetry. Patterns of behaviour recorded were rather unusual compared to other sea turtles in that dives were mainly deep, largely benthic and exceptionally long (>2 h) in some cases, characteristics typical of over-wintering turtles in colder environments. One individual occupied shallow coastal foraging zones, while the others foraged far from land (probably on the seabed) in relatively deep water (>100 m). Individuals performed long dives (frequently >100 min), but from the short post-dive intervals we suggest that these dives were mainly aerobic. Maximum dive depth recorded was 200 ± 20 m (mean maximum depths ranged from 20.1 to 46.7 m across individuals; n = 17328 dives in total; depths ≥3 m were considered ‘dives’) and the maximum duration was 200 ± 20 min (mean durations ranged from 24.5 to 48.0 min across individuals). Temperature profiles indicate that turtles experienced temperatures ranging from 23 to 29°C at the surface, with the lowest temperature recorded (18.7°C) at a depth of 98 m. Only 6.9% of the dives were in water <20°C. From time-allocation at depth (TAD) scores, we demonstrated that many dives reaching the known or inferred sea bottom were U-shaped, but there was no apparent diel signal in dive depth. This suggests that many benthic dives were not associated exclusively with resting behaviour and likely had a foraging component as well. The ability to perform long benthic dives allows this species to exploit deeper benthic environments in addition to the shallow coastal areas more generally occupied by adult hard-shelled sea turtles (e.g. green and hawksbill turtles). Deep benthic dives also occur in certain marine mammals (e.g. narwhals) and sea birds (e.g. rockhopper penguins) and therefore seem to be a general foraging strategy exploited by animals that can perform long dives.

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This paper addresses the problem of tracking moving objects of variable appearance in challenging scenes rich with features and texture. Reliable tracking is of pivotal importance in surveillance applications. It is made particularly difficult by the nature of objects encountered in such scenes: these too change in appearance and scale, and are often articulated (e.g. humans). We propose a method which uses fast motion detection and segmentation as a constraint for both building appearance models and their robust propagation (matching) in time. The appearance model is based on sets of local appearances automatically clustered using spatio-kinetic similarity, and is updated with each new appearance seen. This integration of all seen appearances of a tracked object makes it extremely resilient to errors caused by occlusion and the lack of permanence of due to low data quality, appearance change or background clutter. These theoretical strengths of our algorithm are empirically demonstrated on two hour long video footage of a busy city marketplace.

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This research investigates the state estimation problem in close-range involving multiple targets using Doppler Radar. As the main theme is based on measurements with linear sensor arrays, optimal sensor arrangements are studied for two most popular measurement technologies: Angle-of-Arrival and range based localization systems.

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Tracking services play a fundamental role in the smartphone ecosystem. While their primary purpose is to provide a smartphone user with the ability to regulate the extent of sharing private information with external parties, these services can also be misused by advertisers in order to boost revenues. In this paper, we investigate tracking services on the Android and iOS smartphone platforms. We present a simple and effective way to monitor traffic generated by tracking services to and from the smartphone and external servers. To evaluate our work, we dynamically execute a set of Android and iOS applications, collected from their respective official markets. Our empirical results indicate that even if the user disables or limits tracking services on the smartphone, applications can by-pass those settings and, consequently, leak private information to external parties. On the other hand, when testing the location 'on' setting, we notice that generally location is not tracked.

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Periodically tracking public sentiment toward television advertising (TVA) is an important barometer for the advertising industry and its myriad stakeholders. To date, however, most studies of consumers’ attitudes to TVA have been cross-sectional. This study, alternatively, provides a quasi-longitudinal examination of Australian attitudes toward TVA across four time points (2002, 2005, 2008, and 2010). Findings suggest that although attitudes toward TVA are generally negative, in fact they have not deteriorated over time. Considerable scope consequently exists for improving consumer attitudes toward TVA.

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Currently, employers tend to fast rack works where construction can begin while design is still incomplete following three main phases of procurement. This session details a case study of a fast track overseas super high rise building, where an Australian firm acted as a technical expert to provide a detailed report on the failure of the shoring system, while construction of five basements had just started next to a marina. The lessons learnt from the case study are summarized with recommendations to have better practice of the fast track method in complex high rise buildings.

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The use of tracking settings in smartphones facilitates the provision of tailored services to users by allowing service providers access to unique identifiers stored on the smartphones. In this paper, we investigate the 'tracking off' settings on the Blackberry 10 and Windows Phone 8 platforms. To determine if they work as claimed, we set up a test bed suitable for both operating systems to capture traffic between the smartphone and external servers. We dynamically execute a set of similar Blackberry 10 and Windows Phone 8 applications, downloaded from their respective official markets. Our results indicate that even if users turn off tracking settings in their smartphones, some applications leak unique identifiers without their knowledge. © 2014 Springer International Publishing Switzerland.