Real Time UAV Altitude, Attitude and Motion Estimation form Hybrid Stereovision

International audienceKnowledge of altitude, attitude and motion is essential for an Unmanned Aerial Vehicle during crit- ical maneuvers such as landing and take-off. In this paper we present a hybrid stereoscopic rig composed of a fisheye and a perspective camera for vision-based navigation. In contrast to classical stereoscopic systems based on feature matching, we propose methods which avoid matching between hybrid views. A plane-sweeping approach is proposed for estimating altitude and de- tecting the ground plane. Rotation and translation are then estimated by decoupling: the fisheye camera con- tributes to evaluating attitude, while the perspective camera contributes to estimating the scale of the trans- lation. The motion can be estimated robustly at the scale, thanks to the knowledge of the altitude. We propose a robust, real-time, accurate, exclusively vision-based approach with an embedded C++ implementation. Although this approach removes the need for any non-visual sensors, it can also be coupled with an Inertial Measurement Unit

Active SLAM: A Review On Last Decade

This article presents a comprehensive review of the Active Simultaneous Localization and Mapping (A-SLAM) research conducted over the past decade. It explores the formulation, applications, and methodologies employed in A-SLAM, particularly in trajectory generation and control-action selection, drawing on concepts from Information Theory (IT) and the Theory of Optimal Experimental Design (TOED). This review includes both qualitative and quantitative analyses of various approaches, deployment scenarios, configurations, path-planning methods, and utility functions within A-SLAM research. Furthermore, this article introduces a novel analysis of Active Collaborative SLAM (AC-SLAM), focusing on collaborative aspects within SLAM systems. It includes a thorough examination of collaborative parameters and approaches, supported by both qualitative and statistical assessments. This study also identifies limitations in the existing literature and suggests potential avenues for future research. This survey serves as a valuable resource for researchers seeking insights into A-SLAM methods and techniques, offering a current overview of A-SLAM formulation.Comment: 34 pages, 8 figures, 6 table

A library of infectious hepatitis C viruses with engineered mutations in the E2 gene reveals growth-adaptive mutations that modulate interactions with scavenger receptor class B type I

While natural hepatitis C virus (HCV) infection results in highly diverse quasispecies of related viruses over time, mutations accumulate more slowly in tissue culture, in part because of the inefficiency of replication in cells. To create a highly diverse population of HCV particles in cell culture and identify novel growth-enhancing mutations, we engineered a library of infectious HCV with all codons represented at most positions in the ectodomain of the E2 gene. We identified many putative growth-adaptive mutations and selected nine highly represented E2 mutants for further study: Q412R, T416R, S449P, T563V, A579R, L619T, V626S, K632T, and L644I. We evaluated these mutants for changes in particle-to-infectious-unit ratio, sensitivity to neutralizing antibody or CD81 large extracellular loop (CD81-LEL) inhibition, entry factor usage, and buoyant density profiles. Q412R, T416R, S449P, T563V, and L619T were neutralized more efficiently by anti-E2 antibodies and T416R, T563V, and L619T by CD81-LEL. Remarkably, all nine variants showed reduced dependence on scavenger receptor class B type I (SR-BI) for infection. This shift from SR-BI usage did not correlate with a change in the buoyant density profiles of the variants, suggesting an altered E2-SR-BI interaction rather than changes in the virus-associated lipoprotein-E2 interaction. Our results demonstrate that residues influencing SR-BI usage are distributed across E2 and support the development of large-scale mutagenesis studies to identify viral variants with unique functional properties. IMPORTANCE Characterizing variant viruses can reveal new information about the life cycle of HCV and the roles played by different viral genes. However, it is difficult to recapitulate high levels of diversity in the laboratory because of limitations in the HCV culture system. To overcome this limitation, we engineered a library of mutations into the E2 gene in the context of an infectious clone of the virus. We used this library of viruses to identify nine mutations that enhance the growth rate of HCV. These growth-enhancing mutations reduced the dependence on a key entry receptor, SR-BI. By generating a highly diverse library of infectious HCV, we mapped regions of the E2 protein that influence a key virus-host interaction and provide proof of principle for the generation of large-scale mutant libraries for the study of pathogens with great sequence variability

Antioxidant effects of resveratrol in cardiovascular, cerebral and metabolic diseases.

Resveratrol-a natural polyphenolic compound-was first discovered in the 1940s. Although initially used for cancer therapy, it has shown beneficial effects against most cardiovascular and cerebrovascular diseases. A large part of these effects are related to its antioxidant properties. Here we review: a) the sources, the metabolism, and the bioavailability of resveratrol; b) the ability of resveratrol to modulate redox signalling and to interact with multiple molecular targets of diverse intracellular pathways; c) its protective effects against oxidative damage in cardio-cerebro-vascular districts and metabolic disorders such as diabetes; and d) the evidence for its efficacy and toxicity in humans. The overall aim of this review is to discuss the frontiers in the field of resveratrol's mechanisms, bioactivity, biology, and health-related use

The Digital Transformation of the Manufacturing Industry : Metamorphic Changes and Value Creation in the Industrial Network

The Industry 4.0 trend poses many challenges for the manufacturing industry and societies generally. The trend presents new challenges and opportunities related to industrial competitiveness and sustainability, as industrial firms adopt digital technologies to change how they interact and exchange data across their industrial network.  The introduction of digital technologies is resulting in a complex technological and organizational structural change process called digital transformation, which sees interfirm interactions, capabilities and identities changed across the industrial network. The digital transformation change process has remained relatively ill-defined, as most industries are yet to show the full potential of successful digital transformation. Firms within the manufacturing industry still have difficulties grasping the impact and costs of Industry 4.0 and of the digital transformation process. The prevailing assumption in the literature is that industries will achieve value creation simply by engaging with digital technologies, either in higher revenues, profitability or both if they are successful. The change process affects all aspects of industrial network, from the single product functionality and production process efficiency to interfirm business interactions, thus affecting in many regards value creation in the industrial network. By employing an Industrial Marketing and Purchasing approach, the dissertation analyzes the issues of interaction, change and value creation in the resource context of two large industrial networks undergoing complex digital transformations. This article dissertation will present four qualitative studies of two large manufacturing industrial network undergoing complex digital transformations with the interaction approach. This dissertation presents several findings and contributions specific to the digital transformation change process, including the presence of metamorphic irreversible and interactive changes challenging the status quo of interactions and value creation in the resource context, creating conflicts, controversies, and friction effects. It also underscores the importance of organizational elements of organizations for the digital transformation, and how a unique combination of changes across the resource context, from new roles to new ways of working allow the industrial network to create value beyond simple technological incremental innovations. The dissertation presents a theory of metamorphic change in the industrial network, to describe complex change processes like the digital transformation.

Can Blockchain Technology Solve Trust Issues in Industrial Networks?

Since its inception about a decade ago, practitioners and researchers alike have been drawn to the blockchain technology vibe. Advocates of blockchain argue that the technology is taking us to truly ‘trust-free’ transactions. A long list of applications of blockchain has also been proposed in a relatively short period of time. However, a closer look into the literature reveals two shortcomings. To start with, the substantial proportion of the research on blockchain has focused on addressing the technical aspects of blockchain—design and features— as well as legal issues. However, there is a lack of knowledge on how blockchain technology can be used to solve practical problems faced by organizations in different sectors and industries—measurement and value, trust, management and organization. The state-of-the-art also shows that there is a dominance of conceptual and design-oriented research paradigms. To address this gap and respond to the calls for further research, this paper presents a research plan for a longitudinal case study to investigate whether blockchain technology can affect the way organizations conduct their business relationships

Automatic Camera-Based Microscope Calibration for a Telemicromanipulation System Using a Virtual Pattern

International audienceIn the context of virtualized-reality-based telemicromanipulation, this paper presents a visual calibration technique for an optical microscope coupled to a charge-coupled device (CCD) camera. The accuracy and flexibility of the proposed automatic virtual calibration method, based on parallel single-plane properties, are outlined. In contrast to standard approaches, a 3-D virtual calibration pattern is constructed using the micromanipulator tip with subpixel-order localization in the image frame. The proposed procedure leads to a linear systemwhose solution provides directly both the intrinsic and extrinsic parameters of the geometrical model. Computer simulations and real data have been used to test the proposed technique, and promising results have been obtained. Based on the proposed calibration techniques, a 3-D virtual microenvironment of the workspace is reconstructed through the real-time imaging of two perpendicular optical microscopes. Our method provides a flexible, easy-to-use technical alternative to the classical techniques used in micromanipulation systems