2,320 research outputs found
Stereovision and augmented reality for closed loop control of grasping in hand prostheses
No full textObjective. Technologically advanced assistive devices are nowadays available to restore grasping, but effective and effortless control integrating both feed-forward (commands) and feedback (sensory information) is still missing. The goal of this work was to develop a user friendly interface for the semi-automatic and closed-loop control of grasping and to test its feasibility. Approach. We developed a controller based on stereovision to automatically select grasp type and size and augmented reality (AR) to provide artificial proprioceptive feedback. The system was experimentally tested in healthy subjects using a dexterous hand prosthesis to grasp a set of daily objects. The subjects wore AR glasses with an integrated stereo-camera pair, and triggered the system via a simple myoelectric interface. Main results. The results demonstrated that the subjects got easily acquainted with the semi-autonomous control. The stereovision grasp decoder successfully estimated the grasp type and size in realistic, cluttered environments. When allowed (forced) to correct the automatic system decisions, the subjects successfully utilized the AR feedback and achieved close to ideal system performance. Significance. The new method implements a high level, low effort control of complex functions in addition to the low level closed-loop control. The latter is achieved by providing rich visual feedback, which is integrated into the real life environment. The proposed system is an effective interface applicable with small alterations for many advanced prosthetic and orthotic/therapeutic rehabilitation devices
Multiple eruptive squamous cell carcinomas: a possible clinical sign in melanoma patients treated with vemurafenib
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Anthocyanins and phenolic acids from Prunus spinosa L. encapsulation in halloysite and maltodextrin based carriers
No full textHalloysite, as an inorganic nanoclay material, maltodextrin, as a carbohydrate polymer, and the composite made of them were tested as encapsulating agents for blackthorn (Prunus spinosa L.) extract rich in phenolic acids and anthocyanins. For the halloysite nanotubes loading cyclic vacuum technique was applied, and maltodextrin encapsulates were prepared by freeze-drying process. Thermogravimetric analysis confirmed that blackthorn extract was encapsulated with halloysite, maltodextrin, and maltodextrin-halloysite composite. The cytotoxic effect of the encapsulates was tested in tumor (MCF7 and HT-29) and non-tumor (MRC-5) cells. The release of four major phenolic compounds: 3-O-caffeoylquinic acid (neochlorogenic acid) and, cyanidin 3-O-glucoside, cyanidin 3-O-rutinoside, and peonidin 3-O-rutinoside was tested. Addition of extract and encapsulates in yoghurt prolonged the release of blackthorn bioactives. These results indicate that blackthorn extract and its halloysite and maltodextrin encapsulates have potential in the production of functional foods, food supplements, and pharmaceuticals
Roman land division in Istria, Croatia : historiography, LiDAR, structural survey and excavations
No full textAbstract: Many interpretations of the ancient cadastre of the Roman colonies of Pola and Parentium on the Istrian pen-insula in Croatia have been offered recently on the basis of satellite imagery and the Croatian topographic map. This grid, spreading continuously over an area of roughly 1200 km2, was identified through numerous structures which correspond to the ancient Roman metric system, but they were never a part of further re-search. This approach enabled identification of structures that were most often visible in the contemporary cadastre, like modern roads or field boundaries, but gaps were left in areas where the modern cadastre did not reflect the ancient one. Until the commission of airborne laser scanning (ALS or LiDAR), from which our research began, one of these gaps was on the northern side of the Lim bay, in the Municipality of Vrsar. Inter-pretation of ALS data resulted in detecting different, multi-temporal spatial organisations of the landscape, among which were numerous, previously unidentified, remains of the Roman limites. The results of this inter-pretation guided the field inspection. Different surface manifestations of individual remains were categorized, and it was defined which are the original Roman structures. The results of this structural survey subsequently guided the archaeological excavations. Only with the combination of these procedures it was possible to un-derstand the original construction of the limites
Precursors of non-Markovianity
No full textUsing the paradigm of information backflow to characterize a non-Markovian evolution, we introduce so-called precursors of non-Markovianity, i.e. necessary properties that the system and environment state must exhibit at earlier times in order for an ensuing dynamics to be nonMarkovian. In particular, we consider a quantitative framework to assess the role that established system-environment correlations together with changes in environmental states play in an emerging non-Markovian dynamics. By defining the relevant contributions in terms of the Bures distance, which is conveniently expressed by means of the quantum state fidelity, these quantities are well defined and easily applicable to a wide range of physical settings. We exemplify this by studying our precursors of non-Markovianity in discrete and continuous variable non-Markovian collision models
Efficient X-band transmitter with integrated GaN power amplifier and supply modulator
No full textIn this paper, we present a high-efficiency transmitter based on an integrated circuit (IC) supply modulator implemented in the same 0.15μm gallium nitride (GaN)-on-SiC RF process as the power amplifier (PA) monolithic microwave IC. The X-band 10-W two-stage PA is designed for stable operation with minimal drain capacitance, which enables fast supply modulation. The multilevel supply modulator provides eight voltage levels with 3-bit digital control [(power digital-to-analog converter (pDAC)], achieving a state-of-the-art slew rate of 5 kV/μs. Characterization of the dynamic R ON of the GaN switches allows the development of an efficiency model for the pDAC and an investigation of the effects of the pDAC internal resistance on the PA performance, resulting in a comprehensive efficiency model for the supply-modulated PA. The flexible compact transmitter consisting of the PA and pDAC ICs shows high efficiency in backoff for a variety of signals, both for radar and communications. Measured results for amplitude- A nd frequency-modulated radar pulses show a composite power-added efficiency (CPAE) of 44% with a peak power of 10 W at 9.57 GHz, with simultaneous spectral confinement and 52-dB improvement of the first time sidelobe. For a 20-MHz high peak-to-average ratio LTE signal, the CPAE increases from 11% to 32% compared to a fixed supply voltage transmitter, while linearity under dynamic supply operation is maintained through digital predistortion
Active baseband drain-supply terminal load-pull of an X-band GaN MMIC PA
No full textIn this paper, we present a linearity and efficiency investigation of a GaN MMIC power amplifier (PA) designed for supply modulation, by low-frequency (LF) active load-pull at the drain supply terminal, with the PA operating under RF carrier large signal excitation. The baseband load-pull is performed at frequencies up to 6 MHz while the PA is operating at 10 GHz
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