893 research outputs found

    Object-oriented Matlab adaptive optics toolbox

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    Object-Oriented Matlab Adaptive Optics (OOMAO) is a Matlab toolbox dedicated to Adaptive Optics (AO) systems. OOMAO is based on a small set of classes representing the source, atmosphere, telescope, wavefront sensor, Deformable Mirror (DM) and an imager of an AO system. This simple set of classes allows simulating Natural Guide Star (NGS) and Laser Guide Star (LGS) Single Conjugate AO (SCAO) and tomography AO systems on telescopes up to the size of the Extremely Large Telescopes (ELT). The discrete phase screens that make the atmosphere model can be of infinite size, useful for modeling system performance on large time scales. OOMAO comes with its own parametric influence function model to emulate different types of DMs. The cone effect, altitude thickness and intensity profile of LGSs are also reproduced. Both modal and zonal modeling approach are implemented. OOMAO has also an extensive library of theoretical expressions to evaluate the statistical properties of turbulence wavefronts. The main design characteristics of the OOMAO toolbox are object-oriented modularity, vectorized code and transparent parallel computing. OOMAO has been used to simulate and to design the Multi-Object AO prototype Raven at the Subaru telescope and the Laser Tomography AO system of the Giant Magellan Telescope. In this paper, a Laser Tomography AO system on an ELT is simulated with OOMAO. In the first part, we set-up the class parameters and we link the instantiated objects to create the source optical path. Then we build the tomographic reconstructor and write the script for the pseudo-open-loop controller

    Nonverbal Communication in Relation to Women's Experiences of Self and Body: A Mixed Methods Examination

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    Understanding how nonverbal behaviour imparts information about women’s attractiveness and body image is important, given that peers are a source of information about appearance (e.g., Tiggemann, 2011). Research has demonstrated that negative messages from peers are associated with body dissatisfaction and disordered eating among females (e.g., Vincent & McCabe, 2000) but less is known about nonverbal communication. The current research examined women’s nonverbal behaviour, physical appearance, and body image within interactions. An explanatory sequential mixed method design was used. The initial quantitative study examined the relationship between immediacy and women’s body attractiveness, facial attractiveness, and body image in peer-dyad interactions (n = 80 dyads). Participants were videotaped interacting in a laboratory setting for 15 minutes and then completed self-report measures of their interaction partner for immediacy and attractiveness. They also completed self-report measures of their body image, internalization of the thin ideal, and appearance comparison. The researcher measured body mass index. Results indicated that as perceptions of body and facial attractiveness and body image of an interaction partner decrease, so does the immediacy shown towards the partner. Following the quantitative component, a follow-up qualitative study explored women’s experiences of their bodies and themselves in relation to nonverbal communication in interactions with peers. It was conducted according to Interpretative Phenomenological Analysis (Smith, Flowers, & Larkin, 2009). A subset of participants (n = 4) was invited to review their videotaped conversation and participate in a semi-structured interview with the researcher. Results indicated that women experience complex processes within interactions, including comparing and judging as well as body consciousness and that both the egocentric and sociocentric parts of the self are involved. Results also illuminated women’s experience of resisting the influence of adhering to society’s ideals of appearance. Together, the findings indicate that weight-based bias is present within everyday interactions among women. It is hoped that this research will bring attention to biases that are routinely communicated in subtle ways to decrease it and positively impact women’s experiences of themselves and their bodies

    WCAM: secured video surveillance with digital rights management

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    The WCAM project aims to provide an integrated system for secure delivery of video surveillance data over a wireless network, while remaining scalable and robust to transmission errors. To achieve these goals., the content is encoded in Motion-JPEG2000 and streamed with a specific RTP protocol encapsulation to prevent the loss of packets containing the most essential data. Protection of the video data is performed at content level using the standardized JPSEC syntax along with flexible encryption of quality layers or resolution levels. This selective encryption respects the JPEG2000 structure of the stream, not only ensuring end-to-end ciphered delivery, but also enabling dynamic content adaptation within the wireless network (quality of service, adaptation to the user's terminal). A DRM (Digital Rights Management) solution, called OpenSDRM is added to manage all authenticated peers on the WLAN (from end-users to cameras), as well as to manage the rights to access and display conditionally the video data. This whole integrated architecture addresses several security problems such as data encryption, integrity, access control and rights management. Using several protection lavers, the level of confidentiality can depend both on content characteristics and user rights, thus also addressing the critical issue of privacy.info:eu-repo/semantics/acceptedVersio

    The Role of Power and Negotiation in Online Deception

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    The purpose of this paper is to advance theoretical understanding of the important role of both power and negotiation during online deception. By so doing, the paper provides insight into the relationship between perpetrator and victim in Internet fraud. The growing prevalence of Internet Fraud continues to be a burden to both society and individuals. In an attempt to better understand Internet fraud and online deception, this article attempts to build an interactive model, based upon the dimensions of power and negotiation from the management and psychology literature. Using the model presented, the article examines the effects of the Internet on the communication process that takes place between perpetrator and victim. Finally, the article discusses some of the major tactics employed to appeal to each power type in predominant fraud forms, as well exploring future types of fraud

    The IS Core: An Integration of the Core IS Courses

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    This paper describes an innovative, integrated implementation of the core Information Systems courses. While the published IS curriculum provides standards on course content, it gives little direction on the implementation of the courses. At Brigham Young University, we have reengineered the traditional topics of analysis, database, design, development, networking, etc. into an integrated, 24-hour course block called the “IS Core”. Instead of students moving from class to class, professors now rotate through integrated subjects in a common classroom environment. The IS Core has allowed the department to increase the rigor and integration between subjects so students see the entire systems process and has provided opportunities for cross-topic assignments and integrated exercises. Finally, it has resulted in unintended, additional benefits like increased student culture and student ownership of the major

    Drug Delivery Micropump with Built-In Monitoring

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    AbstractWe report on the fabrication of the first MEMS micropump including an integrated pressure sensor. The signal of this sensor allows direct insight into the pump's operating dynamics and enables real-time self-monitoring. We demonstrate the changes in the sensor signal under different pumping conditions, including the presence of air in the pumping chamber and a downstream occlusions. Deviations from normal operating conditions create clear and characteristic deviations from the normal signal. These deviations will be exploited to detect extraordinary or faulty pumping conditions during use

    Role of environmental factors for the vertical distribution (0–1000 m) of marine bacterial communities in the NW Mediterranean Sea

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    Bacterioplankton plays a central role in energy and matter fluxes in the sea, yet the factors that constrain its variation in marine systems are still poorly understood. Here we use the explanatory power of direct multivariate gradient analysis to evaluate the driving forces exerted by environmental parameters on bacterial community distribution in the water column. We gathered and analysed data from a one month sampling period from the surface to 1000 m depth at the JGOFS-DYFAMED station (NW Mediterranean Sea). This station is characterized by very poor horizontal advection currents which makes it an ideal model to test hypotheses on the causes of vertical stratification of bacterial communities. Capillary electrophoresis single strand conformation polymorphism (CE-SSCP) fingerprinting profiles analyzed using multivariate statistical methods demonstrated a vertical zonation of bacterial assemblages in three layers, above, in or just below the chlorophyll maximum and deeper, that remained stable during the entire sampling period. Through the use of direct gradient multivariate ordination analyses we demonstrate that a complex array of biogeochemical parameters is the driving force behind bacterial community structure shifts in the water column. Physico-chemical parameters such as phosphate, nitrate, salinity and to a lesser extent temperature, oxygen, dissolved organic carbon and photosynthetically active radiation acted in synergy to explain bacterial assemblages changes with depth. Analysis of lipid biomarkers of organic matter sources and fates suggested that bacterial community structure in the surface layers was in part explained by lipids of chloroplast origin. Further detailed analysis of pigment-based phytoplankton diversity gave evidence of a compartmentalized influence of several phytoplankton groups on bacterial community structure in the first 150 m depth

    Capture-Recapture Reveals Heterogeneity in Habitat-Specific Mongoose Densities and Spatiotemporal Variability in Trapping Success in St. Kitts, West Indies

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    The small Indian mongoose (Urva auropunctata) is a non-native invasive species across the Caribbean and a rabies reservoir on at least four islands in the region. Although previous studies reported mongoose density estimates in their non-native range, the variability in trapping designs, study seasonality, and analytical methods among studies precludes direct comparisons. This study is the first to report mongoose densities for the island of St. Kitts, West Indies. Our objective was to quantify mongoose densities across four habitats characteristic for the island. High capture and recapture rates in this study resulted in detailed estimates of spatial heterogeneity in mongoose densities, ranging from 0.53 (CI95: 0.46–0.61) mongooses/ha in suburban habitat to 5.85 (CI95: 4.42–7.76) mongooses/ha in nearby dry forest. Estimates were robust to the estimation method used (correlation among methods, r \u3e 0.9). Female-biased sex ratios estimated from fall season versus mostly unbiased sex ratios estimated from summer season suggests seasonality in capture success resulting from differences in sex-specific activity patterns of mongooses. We found no effect of habitat characteristics, at the scale of trap placements, associated with mongoose capture success

    Laser Guide Stars for Extremely Large Telescopes: Efficient Shack-Hartmann Wavefront Sensor Design using Weighted center-of-gravity algorithm

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    Over the last few years increasing consideration has been given to the study of Laser Guide Stars (LGS) for the measurement of the disturbance introduced by the atmosphere in optical and near-infrared astronomical observations from the ground. A possible method for the generation of a LGS is the excitation of the Sodium layer in the upper atmosphere at approximately 90 km of altitude. Since the Sodium layer is approximately 10 km thick, the artificial reference source looks elongated, especially when observed from the edge of a large aperture. The spot elongation strongly limits the performance of the most common wavefront sensors. The centroiding accuracy in a Shack-Hartmann wavefront sensor, for instance, decreases proportionally to the elongation (in a photon noise dominated regime). To compensate for this effect a straightforward solution is to increase the laser power, i.e. to increase the number of detected photons per subaperture. The scope of the work presented in this paper is twofold: an analysis of the performance of the Weighted Center of Gravity algorithm for centroiding with elongated spots and the determination of the required number of photons to achieve a certain average wavefront error over the telescope aperture.Comment: 10 pages, 14 figure
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