233 resultados para 135-839
Resumo:
Computer vision is much more than a technique to sense and recover environmental information from an UAV. It should play a main role regarding UAVs’ functionality because of the big amount of information that can be extracted, its possible uses and applications, and its natural connection to human driven tasks, taking into account that vision is our main interface to world understanding. Our current research’s focus lays on the development of techniques that allow UAVs to maneuver in spaces using visual information as their main input source. This task involves the creation of techniques that allow an UAV to maneuver towards features of interest whenever a GPS signal is not reliable or sufficient, e.g. when signal dropouts occur (which usually happens in urban areas, when flying through terrestrial urban canyons or when operating on remote planetary bodies), or when tracking or inspecting visual targets—including moving ones—without knowing their exact UMT coordinates. This paper also investigates visual serving control techniques that use velocity and position of suitable image features to compute the references for flight control. This paper aims to give a global view of the main aspects related to the research field of computer vision for UAVs, clustered in four main active research lines: visual serving and control, stereo-based visual navigation, image processing algorithms for detection and tracking, and visual SLAM. Finally, the results of applying these techniques in several applications are presented and discussed: this study will encompass power line inspection, mobile target tracking, stereo distance estimation, mapping and positioning.
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The arsenite minerals finnemanite Pb5(As3+O3)3Cl been studied by Raman spectroscopy. The most intense Raman band at 871 cm-1 is assigned to the ν1 (AsO3)3- symmetric stretching vibration. Three Raman bands at 898, 908 and 947 cm-1 are assigned to the ν3 (AsO3)3- antisymmetric stretching vibration. The observation of multiple antisymmetric stretching vibrations suggest that the (AsO3)3- units are not equivalent in the molecular structure of finnemanite. Two Raman bands at 383 and 399 cm-1 are assigned to the ν2 (AsO3)3- bending modes. DFT calculations enabled the position of AsO32- symmetric stretching mode at 839 cm-1, the antisymmetric stretching mode at 813 cm-1, and the deformation mode at 449 cm-1 to be calculated. Raman bands are observed at 115, 145, 162, 176, 192, 216 and 234 cm-1 as well. The two most intense bands are observed at 176 and 192 cm-1. These bands are assigned to PbCl stretching vibrations and result from transverse/ longitudinal splitting. The bands at 145 and 162 cm-1 may be assigned to Cl-Pb-Cl bending modes.
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The selected arsenite minerals leiteite, reinerite and cafarsite have been studied by Raman spectroscopy. DFT calculations enabled the position of AsO22- symmetric stretching mode at 839 cm-1, the antisymmetric stretching mode at 813 cm-1, and the deformation mode at 449 cm-1 to be calculated. The Raman spectrum of leiteite shows bands at 804 and 763 cm-1 assigned to the As2O42- symmetric and antisymmetric stretching modes. The most intense Raman band of leiteite is the band at 457 cm-1 and is assigned to the ν2 As2O42- bending mode. A comparison of the Raman spectrum of leiteite is made with the arsenite minerals reinerite and cafarsite.
Resumo:
The mixed anion mineral dixenite has been studied by Raman spectroscopy, complimented with infrared spectroscopy. The Raman spectrum of dixenite shows bands at 839 and 813 cm-1 assigned to the (AsO3)3- symmetric and antisymmetric stretching modes. The most intense Raman band of dixenite is the band at 526 cm-1 and is assigned to the ν2 AsO33- bending mode. DFT calculations enabled the position of AsO22- symmetric stretching mode at 839 cm-1, the antisymmetric stretching mode at 813 cm-1, and the deformation mode at 449 cm-1 to be calculated. Raman bands at 1026 and 1057 cm-1 are assigned to the SiO42- symmetric stretching vibrations and at 1349 and 1386 cm-1 to the SiO42- antisymmetric stretching vibrations. Both Raman and infrared spectra indicate the presence of water in the structure of dixenite. This brings into question the commonly accepted formula of dixenite as CuMn2+14Fe3+(AsO3)5(SiO4)2(AsO4)(OH)6. The formula may be better written as CuMn2+14Fe3+(AsO3)5(SiO4)2(AsO4)(OH)6•xH2O.
Resumo:
Telecommunications is a key component in any country's economic infrastructure, requiring a vast amount of capital injection and ongoing technical support and innovation. Many developing countries experience handicaps in accessing capital and sustaining the required technical capability in their industralisation process. Therefore, attracting both capital investments and expertise by attuning the developing country's economic policies and legal environment to meet investors' expectations is a priority. Privatisation has been seen as a triumph by international institutions such as the World Bank, and a major requirement for developing economies to industrialise. However from a regulatory perspective, this process is far from straightforward. Implementing economic policies requires a number of regulations and regulatory instruments to be in place. Apart from the need for an independent regulator, regulatory outcomes are often dependent on the willingness of various stakeholders to comply with the course of actions undertaken by authorities. This article examines the factors steering the processes and changes in the telecommunication reforms of Indonesia and China.
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OBJECTIVE: Parents coping with a diagnosis of advanced cancer experience distress and guilt about the impact of the disease on their children but report that there are few resources specific to advanced disease to guide and support them in discussions with their children. Although some resources have been developed to assist parents with advanced cancer, it appears that these are not widely disseminated. METHODS: To determine the need for a brief resource that could be given to parents at the point of diagnosis of advanced cancer, including its content, in-depth interviews were conducted with eight women with advanced breast cancer. RESULTS: Women confirmed that they had received minimal assistance from health professionals in discussing the diagnosis with their children, and even when professional counselors were accessed they were not always attuned to the specific needs of parents with advanced cancer. Women felt frustrated that information they did access focused on early disease and lacked the details women felt they needed in coping with advanced cancer. Women felt that there was a need for a brief resource that reassured parents about the impact of the cancer on their children, including practical strategies to help them cope and examples of the ways other parents had responded to difficult questions such as about parental death. A draft resource was developed, critically reviewed by the participants, and their comments incorporated into a final version. SIGNIFICANCE OF RESULTS: This article expands on the themes highlighted by women as important to assist parents with advanced cancer, including the final resource that was developed.
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This paper describes Electronic Blocks, a new robot construction element designed to allow children as young as age three to build and program robotic structures. The Electronic Blocks encapsulate input, output and logic concepts in tangible elements that young children can use to create a wide variety of physical agents. The children are able to determine the behavior of these agents by the choice of blocks and the manner in which they are connected. The Electronic Blocks allow children without any knowledge of mechanical design or computer programming to create and control physically embodied robots. They facilitate the development of technological capability by enabling children to design, construct, explore and evaluate dynamic robotics systems. A study of four and five year-old children using the Electronic Blocks has demonstrated that the interface is well suited to young children. The complexity of the implementation is hidden from the children, leaving the children free to autonomously explore the functionality of the blocks. As a consequence, children are free to move their focus beyond the technology. Instead they are free to focus on the construction process, and to work on goals related to the creation of robotic behaviors and interactions. As a resource for robot building, the blocks have proved to be effective in encouraging children to create robot structures, allowing children to design and program robot behaviors.
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n the field of tissue engineering new polymers are needed to fabricate scaffolds with specific properties depending on the targeted tissue. This work aimed at designing and developing a 3D scaffold with variable mechanical strength, fully interconnected porous network, controllable hydrophilicity and degradability. For this, a desktop-robot-based melt-extrusion rapid prototyping technique was applied to a novel tri-block co-polymer, namely poly(ethylene glycol)-block-poly(epsi-caprolactone)-block-poly(DL-lactide), PEG-PCL-P(DL)LA. This co-polymer was melted by electrical heating and directly extruded out using computer-controlled rapid prototyping by means of compressed purified air to build porous scaffolds. Various lay-down patterns (0/30/60/90/120/150°, 0/45/90/135°, 0/60/120° and 0/90°) were produced by using appropriate positioning of the robotic control system. Scanning electron microscopy and micro-computed tomography were used to show that 3D scaffold architectures were honeycomb-like with completely interconnected and controlled channel characteristics. Compression tests were performed and the data obtained agreed well with the typical behavior of a porous material undergoing deformation. Preliminary cell response to the as-fabricated scaffolds has been studied with primary human fibroblasts. The results demonstrated the suitability of the process and the cell biocompatibility of the polymer, two important properties among the many required for effective clinical use and efficient tissue-engineering scaffolding.
Resumo:
Tissue engineering allows the design of functionally active cells within supportive bio-scaffolds to promote the development of new tissues such as cartilage and bone for the restoration of pathologically altered tissues. However, all bone tissue engineering applications are limited by a shortage of stem cells. The adult bone marrow stroma contains a subset of nonhematopoietic cells referred to as bone marrow mesenchymal stem cells (BMSCs). BMSCs are of interest because they are easily isolated from a small aspirate of bone marrow and readily generate single- cell-derived colonies. These cells have the capacity to undergo extensive replication in an undifferentiated state ex vivo. In addition, BMSCs have the potential to develop either in vitro or in vivo into distinct mesenchymal tissues, including bone, cartilage, fat, tendon, muscle, and marrow stroma. Thus, BMSCs are an attractive cell source for tissue engineering approaches. However, BMSCs are not homo- geneous and the quantity of stem cells decreases in the bone marrow in aged population. A sequential loss of lineage differentiation potential has been found in the mixed culture of bone marrow stromal cells due to a heterogenous popu- lation. Therefore, a number of studies have proposed that homogenous bone marrow stem cells can be generated from clonal culture of bone marrow cells and that BMSC clones have the greatest potential for the application of bone regeneration in vivo
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Objective: To determine whether bifocal and prismatic bifocal spectacles could control myopia in children with high rates of myopic progression. ---------- Methods: This was a randomized controlled clinical trial. One hundred thirty-five (73 girls and 62 boys) myopic Chinese Canadian children (myopia of 1.00 diopters [D]) with myopic progression of at least 0.50 D in the preceding year were randomly assigned to 1 of 3 treatments: (1) single-vision lenses (n = 41), (2) +1.50-D executive bifocals (n = 48), or (3) +1.50-D executive bifocals with a 3–prism diopters base-in prism in the near segment of each lens (n = 46). ---------- Main Outcome Measures: Myopic progression measured by an automated refractor under cycloplegia and increase in axial length (secondary) measured by ultrasonography at 6-month intervals for 24 months. Only the data of the right eye were used. ---------- Results: Of the 135 children (mean age, 10.29 years [SE, 0.15 years]; mean visual acuity, –3.08 D [SE, 0.10 D]), 131 (97%) completed the trial after 24 months. Myopic progression averaged –1.55 D (SE, 0.12 D) for those who wore single-vision lenses, –0.96 D (SE, 0.09 D) for those who wore bifocals, and –0.70 D (SE, 0.10 D) for those who wore prismatic bifocals. Axial length increased an average of 0.62 mm (SE, 0.04 mm), 0.41 mm (SE, 0.04 mm), and 0.41 mm (SE, 0.05 mm), respectively. The treatment effect of bifocals (0.59 D) and prismatic bifocals (0.85 D) was significant (P < .001) and both bifocal groups had less axial elongation (0.21 mm) than the single-vision lens group (P < .001). ---------- Conclusions: Bifocal lenses can moderately slow myopic progression in children with high rates of progression after 24 months.
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The design and implementation of a high-power (2 MW peak) vector control drive is described. The inverter switching frequency is low, resulting in high-harmonic-content current waveforms. A block diagram of the physical system is given, and each component is described in some detail. The problem of commanded slip noise sensitivity, inherent in high-power vector control drives, is discussed, and a solution is proposed. Results are given which demonstrate the successful functioning of the system
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The late French philosopher Gilles Deleuze has enjoyed significant notoriety and acclaim in American academia over the last 20 years. The unique disciplinary focus of the contemporary discussion has derived from Deleuze the architectural possibilities of biotechnology, systems theory, and digital processualism. While the persistence of Deleuze’s theory of science and the formalist readings of Mille Plateaux and Le Bergsonisme have dominated the reception since the 1990s, few are aware of a much earlier encounter between Deleuze and architects, beginning at Columbia University in the 1970s, which converged on the radical politics of Anti-OEdipus and its American reception in the journal Semiotext(e), through which architecture engaged a much broader discourse alongside artists, musicians, filmmakers, and intellectuals in the New York aesthetic underground, of which Deleuze and Félix Guattari were themselves a part.
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This paper presents the results of a structural equation model (SEM) that describes and quantifies the relationships between corporate culture and safety performance. The SEM is estimated using 196 individual questionnaire responses from three companies with better than average safety records. A multiattribute analysis of corporate safety culture characteristics resulted in a hierarchical description of corporate safety culture comprised of three major categories — people, process, and value. These three major categories were decomposed into 54 measurable questions and used to develop a questionnaire to quantify corporate safety culture. The SEM identified five latent variables that describe corporate safety culture: (1) a company’s safety commitment; (2) the safety incentives that are offered to field personal for safe performance; (3) the subcontractor involvement in the company culture; (4) the field safety accountability and dedication; and (5) the disincentives for unsafe behaviors. These characteristics of company safety culture serve as indicators for a company’s safety performance. Based on the findings from this limited sample of three companies, this paper proposes a list of practices that companies may consider to improve corporate safety culture and safety performance. A more comprehensive study based on a larger sample is recommended to corroborate the findings of this study.
Resumo:
This chapter aims to situate values education as a core component of social science pre-service teacher education. In particular, it reflects on an experiment in embedding a values laden Global Education perspective in a fourth year social science curriculum method unit. This unit was designed and taught by the researcher on the assumption that beginning social science teachers need to be empowered with pedagogical skills and new dispositions to deal with value laden emerging global and regional concerns in their secondary school classrooms. Moreover, it was assumed that when pre-service teachers engage in dynamic and interactive learning experiences in their curriculum unit, they commence the process of ‘capacity building’ those skills which prepare them for their own lifelong professional learning. This approach to values education also aimed at providing pre-service teachers with opportunities to ‘create deep understandings of teaching and learning’ (Barnes, 1989, p. 17) by reflecting on the ways in which ‘pedagogy can be transformative’ (Lovat and Toomey, 2011 add page no from Chapter One). It was assumed that this tertiary experience would foster the sine qua non of teaching – a commitment to students and their learning. Central to fostering new ‘dispositions’ through this approach, was the belief in the power of pedagogy to make the difference in enhancing student participation and learning. In this sense, this experiment in values education in secondary social science pre-service teacher education aligns with the Troika metaphor for a paradigm change, articulated by Lovat and Toomey (2009) in Chapter One.