2,028 research outputs found
In-flight calibration of the high-gain antenna pointing for the Mariner Venus-Mercury 1973 spacecraft
The methods used to in-flight calibrate the pointing direction of the Mariner Venus-Mercury 1973 spacecraft high gain antenna and the achieved antenna pointing accuracy are described. The overall pointing calibration was accomplished by performing calibration sequences at a number of points along the spacecraft trajectory. Each of these consisted of articulating the antenna about the expected spacecraft-earth vector to determine systematic pointing errors. The high gain antenna pointing system, the error model used in the calibration, and the calibration and pointing strategy and results are discussed
Denotative and connotative semantics in hypermedia: proposal for a semiotic-aware architecture
In this article we claim that the linguistic-centred view within hypermediasystems needs refinement through a semiotic-based approach before real interoperation between media can be achieved. We discuss the problems of visual signification for images and video in dynamic systems, in which users can access visual material in a non-linear fashion. We describe how semiotics can help overcome such problems, by allowing descriptions of the material on both denotative and connotative levels. Finally we propose an architecture for a dynamic semiotic-aware hypermedia system
Towards a syntax for multimedia semantics
This article describes the current state of the art on representing the fouressential conceptual facets of a multimedia unit, namely the form and substance of content and the form and substance of its expression, and points to the still un solved problems regarding the syntax for media semantics. We first provide a brief overview of the general features of the MPEG-7 standard and its different parts. This serves as a description of the state of the art in content description for audio-visual media. We then analyse the ability of one of these parts for its capability to define structures for describing media semantics. We describe the problems of two currently conflicting MPEG-7 representations of expression-based media semantic, which should be equivalent. We then discuss high-level aspects of media semantics, namely the general problems of an ontology for media semantics. Finally, we talk about the problems of applying the theoretical conceptsto real applications
Supporting the generation of argument structure within video sequences
Browsing is a useful way of exploring annotated media repositories. Sets of links can be automatically created from the annotations associated with the media items in the repository. When there are also relationships among the annotations themselves, such as when the annotation terms are part of a thesaurus, these relations can also be used in the link generation process. Using structured annotations and a thesaurus for generating link sets has two advantages. The first is to evaluate the effectiveness of the terms in the thesaurus for classifying the media items in the repository. The second is to be able to control the links being generated by changing relationships within the thesaurus. The work is illustrated using video segments annotated with argument structures, but we show that the method used is independent of the media types and applicable to systems that use similar annotation structures and typed relations among the
Sensorized Skin With Biomimetic Tactility Features Based on Artificial Cross-Talk of Bimodal Resistive Sensory Inputs
Tactility in biological organisms is a faculty that relies on a variety of specialized receptors. The bimodal sensorized skin, featured in this study, combines soft resistive composites that attribute the skin with mechano- and thermoreceptive capabilities. Mimicking the position of the different natural receptors in different depths of the skin layers, a multi-layer arrangement of the soft resistive composites is achieved. However, the magnitude of the signal response and the localization ability of the stimulus change with lighter presses of the bimodal skin. Hence, a learning-based approach is employed that can help achieve predictions about the stimulus using 4500 probes. Similar to the cognitive functions in the human brain, the cross-talk of sensory information between the two types of sensory information allows the learning architecture to make more accurate predictions of localization, depth, and temperature of the stimulus contiguously. Localization accuracies of 1.8 mm, depth errors of 0.22 mm, and temperature errors of 8.2 °C using 8 mechanoreceptive and 8 thermoreceptive sensing elements are achieved for the smaller inter-element distances. Combining the bimodal sensing multilayer skins with the neural network learning approach brings the artificial tactile interface one step closer to imitating the sensory capabilities of biological skin
Design and Development of a Hydrogel-based Soft Sensor for Multi-Axis Force Control
As soft robotic systems become increasingly complex, there is a need to develop sensory systems which can provide rich state information to the robot for feedback control. Multi-axis force sensing and control is one of the less explored problems in this domain. There are numerous challenges in the development of a multi-axis soft sensor: from the design and fabrication to the data processing and modelling. This work presents the design and development of a novel multi-axis soft sensor using a gelatin-based ionic hydrogel and 3D printing technology. A learning-based modelling approach coupled with sensor redundancy is developed to model the environmentally dependent soft sensors. Numerous real-time experiments are conducted to test the performance of the sensor and its applicability in closed-loop control tasks at 20 Hz. Our results indicate that the soft sensor can predict force values and orientation angle within 4% and 7% of their total range, respectively
Larger portions make me eat more : awareness of the external factors that influence food intake
There is consistent evidence that the amount of food people consume can be influenced by external factors, such as food portion size or the amount of food others are eating. However research studies to date have suggested that people are generally unaware of the influence that these external factors have on food intake. In the present research we directly tested whether consumers are aware of how external factors can affect their food intake. In Study 1 we re-analysed data from a study in which an effect of portion size on food intake was observed and post-consumption, participants were asked whether they believed portion size had influenced their food intake. In Study 2 participants were asked to indicate whether several different external factors known to increase food intake would be likely to increase, decrease or have no effect on how much they would eat in hypothetical scenarios. In Study 1, a large proportion of participants (56%) believed that their food intake was influenced by portion size. In Study 2, a large proportion of participants accurately identified that external factors known to affect eating behaviour would be likely to increase their food intake: portion size (73%), social influence (40%), food variety (75%), and distraction (59%). Together these results suggest that consumers show awareness of the influence that external factors have on their food intake
Designing interactive ambient multimedia applications: requirements and implementation challenges
Ambient intelligence opens new possibilities for interactive multimedia, leading towards applications where the selection, generation and playback of multimedia content can be directed and influenced by multiple users in an ambient sensor network. In this paper, we derive the basic requirements for a flexible infrastructure that can support the integration of multimedia and ambient intelligence, and enable rapid tailoring of interactive multimedia applications. We describe our implementation of the proposed infrastructure, and demonstrate its functionality through several prototype application
Designing interactive ambient multimedia applications: requirements and implementation challenges
Ambient intelligence opens new possibilities for interactive multimedia, leading towards applications where the selection, generation and playback of multimedia content can be directed and influenced by multiple users in an ambient sensor network. In this paper, we derive the basic requirements for a flexible infrastructure that can support the integration of multimedia and ambient intelligence, and enable rapid tailoring of interactive multimedia applications. We describe our implementation of the proposed infrastructure, and demonstrate its functionality through several prototype application
Supporting the generation of argument structure within video sequences
Browsing is a useful way of exploring annotated media repositories. Sets of links can be automatically created from the annotations associated with the media items in the repository. When there are also relationships among the annotations themselves, such as when the annotation terms are part of a thesaurus, these relations can also be used in the link generation process. Using structured annotations and a thesaurus for generating link sets has two advantages. The first is to evaluate the effectiveness of the terms in the thesaurus for classifying the media items in the repository. The second is to be able to control the links being generated by changing relationships within the thesaurus. The work is illustrated using video segments annotated with argument structures, but we show that the method used is independent of the media types and applicable to systems that use similar annotation structures and typed relations among the
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