937 resultados para sensor location problem
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The analysis of multi-modal and multi-sensor images is nowadays of paramount importance for Earth Observation (EO) applications. There exist a variety of methods that aim at fusing the different sources of information to obtain a compact representation of such datasets. However, for change detection existing methods are often unable to deal with heterogeneous image sources and very few consider possible nonlinearities in the data. Additionally, the availability of labeled information is very limited in change detection applications. For these reasons, we present the use of a semi-supervised kernel-based feature extraction technique. It incorporates a manifold regularization accounting for the geometric distribution and jointly addressing the small sample problem. An exhaustive example using Landsat 5 data illustrates the potential of the method for multi-sensor change detection.
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This paper considers the estimation of the geographical scope of industrial location determinants. While previous studies impose strong assumptions on the weighting scheme of the spatial neighbour matrix, we propose a exible parametrisation that allows for di fferent (distance-based) de finitions of neighbourhood and di fferent weights to the neighbours. In particular, we estimate how far can reach indirect marginal e ffects and discuss how to report them. We also show that the use of smooth transition functions provides tools for policy analysis that are not available in the traditional threshold modelling. Keywords: count data models, industrial location, smooth transition functions, threshold models. JEL-Codes: C25, C52, R11, R30.
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The clinical demand for a device to monitor Blood Pressure (BP) in ambulatory scenarios with minimal use of inflation cuffs is increasing. Based on the so-called Pulse Wave Velocity (PWV) principle, this paper introduces and evaluates a novel concept of BP monitor that can be fully integrated within a chest sensor. After a preliminary calibration, the sensor provides non-occlusive beat-by-beat estimations of Mean Arterial Pressure (MAP) by measuring the Pulse Transit Time (PTT) of arterial pressure pulses travelling from the ascending aorta towards the subcutaneous vasculature of the chest. In a cohort of 15 healthy male subjects, a total of 462 simultaneous readings consisting of reference MAP and chest PTT were acquired. Each subject was recorded at three different days: D, D+3 and D+14. Overall, the implemented protocol induced MAP values to range from 80 ± 6 mmHg in baseline, to 107 ± 9 mmHg during isometric handgrip maneuvers. Agreement between reference and chest-sensor MAP values was tested by using intraclass correlation coefficient (ICC = 0.78) and Bland-Altman analysis (mean error = 0.7 mmHg, standard deviation = 5.1 mmHg). The cumulative percentage of MAP values provided by the chest sensor falling within a range of ±5 mmHg compared to reference MAP readings was of 70%, within ±10 mmHg was of 91%, and within ±15mmHg was of 98%. These results point at the fact that the chest sensor complies with the British Hypertension Society (BHS) requirements of Grade A BP monitors, when applied to MAP readings. Grade A performance was maintained even two weeks after having performed the initial subject-dependent calibration. In conclusion, this paper introduces a sensor and a calibration strategy to perform MAP measurements at the chest. The encouraging performance of the presented technique paves the way towards an ambulatory-compliant, continuous and non-occlusive BP monitoring system.
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IMPLICATIONS: A new combined ear sensor was tested for accuracy in 20 critically ill children. It provides noninvasive and continuous monitoring of arterial oxygen saturation, arterial carbon dioxide tension, and pulse rate. The sensor proved to be clinically accurate in the tested range.
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Neuroimaging of the self has focused on high-level mechanisms such as language, memory or imagery of the self and implicated widely distributed brain networks. Yet recent evidence suggests that low-level mechanisms such as multisensory and sensorimotor integration may play a fundamental role in self-related processing. In the present study we used visuotactile multisensory conflict, robotics, virtual reality, and fMRI to study such low-level mechanisms by experimentally inducing changes in self-location. Participants saw a video of a person's back (body) or an empty room (no-body) being stroked while a MR-compatible robotic device stroked their back. The latter tactile input was synchronous or asynchronous with respect to the seen stroking. Self-location was estimated behaviorally confirming previous data that self-location only differed between the two body conditions. fMRI results showed a bilateral activation of the temporo-parietal cortex with a significantly higher BOLD signal increase in the synchronous/body condition with respect to the other conditions. Sensorimotor cortex and extrastriate-body-area were also activated. We argue that temporo-parietal activity reflects the experience of the conscious 'I' as embodied and localized within bodily space, compatible with clinical data in neurological patients with out-of-body experiences.
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Aquest projecte estudia la implementació d’un sistema de localització híbrid amb la combinació del posicionament GPS y el posicionament obtingut mitjançant mesures de potència rebuda (RSS) utilitzant una xarxa de sensors sense fils (WSN). Inicialment s’analitzen les característiques principals de les WSN y les tècniques de posicionament GPS y RSS. A continuació es proposen tècniques de localització híbrides que combinen el posicionament bàsic brindat per la WSN (GPS y RSS)per obtenir posicionament tant en escenaris interiors com exteriors a més d’obtenir una precisió major que les precisions bàsiques. Una vegada s’han analitzat els conceptes bàsics y s’han proposat les tècniques a utilitzar en el sistema de localització híbrida s’expliquen els aspectes d’implementació relacionats amb la programació de la WSN. Finalment, després d’analitzar els resultats de diverses mesures, queda present la necessitat de tècniques d’estimació d’error en el posicionament, per això es proposa una tècnica d’estimació d’error per ser utilitzada en les estimacions híbrides y obtenir així el funcionament desitjat de les tècniques híbrides.
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Dysmenorrhea is common in adolescent years, especially after the onset of ovulatory cycles, usually 2 to 3 years after menarche. Pain and symptoms are responsible for school absenteeism and interruption of sports and social activities. OBJECTIVES: This study aims to measure the prevalence of severe dysmenorrhea and its consequences on adolescent girls in Switzerland. Treatment of dysmenorrhea is discussed and recommendations for clinical practice are given. STUDY DESIGN: Cross sectional survey (SMASH 02) on a nationally representative sample of adolescents (n=7548; 3340 females), aged 16 to 20 years who attended post-mandatory education. A self-administered questionnaire was used to assess the severity of dysmenorrhea and its consequences on daily life pursuit of medical help and medications used. RESULTS: Among 3340 girls, 86.6% suffered from dysmenorrhea-related symptoms: 12.4% described having severe dysmenorrhea and 74.2% moderate dysmenorrhea. Girls with severe dysmenorrhea described heavier consequences on daily activities compared with girls without dysmenorrhea: 47.8% of girls with severe dysmenorrhea reported staying at home and 66.5% declared reducing their sportive activities. Yet, fewer than half have consulted a physician for this complaint and even fewer were treated properly. RECOMMENDATION: The pediatrician has a pivotal role in screening young patients for dysmenorrhea, as well as, educating and effectively treating adolescent girls with menstruation-associated symptoms. Non-steroidal anti-inflammatory drugs are considered the first-line of treatment for dysmenorrhea, and adolescents with symptoms that do not respond to this treatment for 3 menstrual periods should be offered combined oestroprogestative contraception and must be followed up, as non-responders may have an underlying organic pathology. CONCLUSION: Dysmenorrhea is a frequent health problem in adolescent years and adolescent care providers should be able to care for these patients in an efficient way.
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In recent years, the large deployment of mobile devices has led to a massiveincrease in the volume of records of where people have been and when they were there.The analysis of these spatio-temporal data can supply high-level human behaviorinformation valuable to urban planners, local authorities, and designer of location-basedservices. In this paper, we describe our approach to collect and analyze the history ofphysical presence of tourists from the digital footprints they publicly disclose on the web.Our work takes place in the Province of Florence in Italy, where the insights on thevisitors’ flows and on the nationalities of the tourists who do not sleep in town has beenlimited to information from survey-based hotel and museums frequentation. In fact, mostlocal authorities in the world must face this dearth of data on tourist dynamics. In thiscase study, we used a corpus of geographically referenced photos taken in the provinceby 4280 photographers over a period of 2 years. Based on the disclosure of the locationof the photos, we design geovisualizations to reveal the tourist concentration and spatiotemporalflows. Our initial results provide insights on the density of tourists, the points ofinterests they visit as well as the most common trajectories they follow.
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Monitoring of posture allocations and activities enables accurate estimation of energy expenditure and may aid in obesity prevention and treatment. At present, accurate devices rely on multiple sensors distributed on the body and thus may be too obtrusive for everyday use. This paper presents a novel wearable sensor, which is capable of very accurate recognition of common postures and activities. The patterns of heel acceleration and plantar pressure uniquely characterize postures and typical activities while requiring minimal preprocessing and no feature extraction. The shoe sensor was tested in nine adults performing sitting and standing postures and while walking, running, stair ascent/descent and cycling. Support vector machines (SVMs) were used for classification. A fourfold validation of a six-class subject-independent group model showed 95.2% average accuracy of posture/activity classification on full sensor set and over 98% on optimized sensor set. Using a combination of acceleration/pressure also enabled a pronounced reduction of the sampling frequency (25 to 1 Hz) without significant loss of accuracy (98% versus 93%). Subjects had shoe sizes (US) M9.5-11 and W7-9 and body mass index from 18.1 to 39.4 kg/m2 and thus suggesting that the device can be used by individuals with varying anthropometric characteristics.
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Acquiring lexical information is a complex problem, typically approached by relying on a number of contexts to contribute information for classification. One of the first issues to address in this domain is the determination of such contexts. The work presented here proposes the use of automatically obtained FORMAL role descriptors as features used to draw nouns from the same lexical semantic class together in an unsupervised clustering task. We have dealt with three lexical semantic classes (HUMAN, LOCATION and EVENT) in English. The results obtained show that it is possible to discriminate between elements from different lexical semantic classes using only FORMAL role information, hence validating our initial hypothesis. Also, iterating our method accurately accounts for fine-grained distinctions within lexical classes, namely distinctions involving ambiguous expressions. Moreover, a filtering and bootstrapping strategy employed in extracting FORMAL role descriptors proved to minimize effects of sparse data and noise in our task.
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Sex differences in cognition have been largely investigated. The most consistent sex differences favoring females are observed in object location memory involving the left hemisphere whereas the most consistent sex differences favoring males are observed in tasks that require mental rotation involving the right hemisphere. Here we used a task involving these two abilities to see the impact of mental rotation on object location memory. To that end we used a combination of behavioral and event-related potential (ERP) electroencephalography (EEG) measures.A computer screen displayed a square frame of 4 pairs of images (a "teddy" bear, a shoe, an umbrella and a lamp) randomly arranged around a central fixation cross. After a 10-second interval for memorization, images disappeared and were replaced by a test frame with no image but a random pair of two locations marked in black. In addition, this test frame was randomly displayed either in the original orientation (0° rotation) or in the rotated one (90° clockwise - CW - or 90° counterclockwise - CCW). Preceding the test frame, an arrow indicating the presence or the absence of rotation of the frame was displayed on the screen. The task of the participants (15 females and 15 males) was to determine if two marked locations corresponded or not to a pair of identical images. Each response was followed by feedback.Findings showed no significant sex differences in the performance of the original orientation. In comparison with this position, the rotation of the frame produced an equal decrease of male and female performance. In addition, this decrease was significantly higher when the rotation of the frame was in a CCW direction. We further assessed the ERP when the arrow indicated the direction of rotation as stimulus-onset, during four time windows representing major components C1, P1, N1 and N2. Although no sex differences were observed in performance, brain activities differed according to sex. Enhanced amplitudes were found for the CCW compared to CW rotation over the right posterior areas for the P1, N1 and N2 components for men as well as for women. Major topographical differences related to sex were measured for the CW rotation condition as marked lateralized amplitude: left-hemisphere amplitude larger than right one was measured during P1 time range for men. These similar patterns prolonged from P1 to N1 for women. Early distinctions were found in interaction with sex between CCW and CW waveform amplitudes, expressing over anterior electrode sites during C1 time range (0-50 ms post-stimulus).In conclusion (i) women do not outperform men in object location memory in this study (absence of rotation condition); (ii) mental rotation, in particular the direction of rotation, influences performance on object location memory; (iii) CCW rotation is associated with activity in the right parietal hemisphere whereas the CW rotation involves the left parietal hemisphere; (iv) this last effect is less pronounced in males, which could explain why greater involvement of right parietal areas in men and of bilateral posterior areas in women is generally reported in mental rotation tasks; and (v) the early distinctions between both directions of rotation located over anterior sites could be related to sex differences in their respective involvement of control mechanisms.
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Many inflammatory and infectious diseases are characterized by the activation of signaling pathways steaming from the endoplasmic reticulum (ER). These pathways, primarily associated with loss of ER homeostasis, are emerging as key regulators of inflammation and infection. Recent advances shed light on the mechanisms linking ER-stress and immune responses.