2,347 research outputs found
Method to Automatically Register Scattered Point Clouds Based on Principal Pose Estimation
Three dimensional (3-D) modeling is important in applications ranging from manufacturing to entertainment. Multiview registration is one of the crucial steps in 3-D model construction. The automatic establishment of correspondences between overlapping views, without any known initial information, is the main challenge in point clouds registration. An automatic registration algorithm is proposed to solve the registration problem of rigid, unordered, scattered point clouds. This approach is especially suitable for registering datasets that are lacking in features or texture. In general, the existing techniques exhibit significant limitations in the registration of these types of point cloud data. The presented method automatically determines the best coarse registration results by exploiting the statistical technique principal component analysis and outputs translation matrices as the initial estimation for fine registration. Then, the translation matrices obtained from coarse registration algorithms are used to update the original point cloud and the optimal translation matrices are solved using an iterative algorithm. Experimental results show that the proposed algorithm is time efficient and accurate, even if the point clouds are partially overlapped and containing large missing regions
A performance test for a fringe projection scanner in various ambient light conditions
Optical triangulation based scanners have been widely used in industry, mainly for reverse engineering applications and freeform inspection tasks. Error contributions of these optical scanners include many influencing factors like surface quality and material properties of measurand, orientation and scan depth of sensors, ambient light changes, etc. This paper presents a performance evaluation test for a commercially available structured light scanner, under different ambient light conditions. The freeform reference standard developed by National Physical Laboratory is used to identify the influence of ambient light changes to the measurement accuracy
Does digital video enhance student learning in field-based experiments and develop graduate attributes beyond the classroom?
This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Geography in Higher Education on 02/05/2016, available online: http://www.tandfonline.com/doi/full/10.1080/03098265.2016.1141186?src=recsysThe connection between fieldwork and development of graduate attributes is explored in this paper. Digital technologies present opportunities to potentially enhance the learning experience of students undertaking fieldwork, and develop core digital attributes and competencies required by Higher Education Institutions (HEIs) and employers. This paper reports the success of adopting digital video capture in technology-rich field experiments that form part of final year undergraduate courses in Physical Geography at an HEI in New Zealand. Student perceptions were obtained via a range of approaches. Results suggest that deployment of digital video reinforces student learning and connects with core graduate attributes
Folding of a donor–acceptor polyrotaxane by using noncovalent bonding interactions
Mechanically interlocked compounds, such as bistable catenanes and bistable rotaxanes, have been used to bring about actuation in nanoelectromechanical systems (NEMS) and molecular electronic devices (MEDs). The elaboration of the structural features of such rotaxanes into macromolecular materials might allow the utilization of molecular motion to impact their bulk properties. We report here the synthesis and characterization of polymers that contain π electron-donating 1,5-dioxynaphthalene (DNP) units encircled by cyclobis(paraquat-p-phenylene) (CBPQT4+), a π electron-accepting tetracationic cyclophane, synthesized by using the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The polyrotaxanes adopt a well defined “folded” secondary structure by virtue of the judicious design of two DNP-containing monomers with different binding affinities for CBPQT4+. This efficient approach to the preparation of polyrotaxanes, taken alongside the initial investigations of their chemical properties, sets the stage for the preparation of a previously undescribed class of macromolecular architectures
The effects of species ortholog and SNP variation on receptors for free fatty acids
Although it is widely assumed that species orthologs of hormone responsive G protein-coupled receptors will be activated by the same endogenously produced ligand(s), variation in potency, particularly in cases where more than one receptor responds to the same hormone, can result in challenges in defining the contribution of individual receptors in different species. This can create considerably greater issues when using synthetic chemical ligands and, in some cases, may result in a complete lack of efficacy of such a ligand when used in animal models of pathophysiology. In man, the concept that distinct responses of individuals to medicines may reflect differences in the ability of such drugs to bind to or activate single nucleotide polymorphism variants of receptors is more established as a concept but, in many cases, clear links between such variants that are associated with disease phenotypes and substantial differences in receptor ligand pharmacology have been more difficult to obtain. Herein, we consider each of these issues for the group of receptors, FFA1-FFA4, defined to be activated by free fatty acids of varying chain length which, based on their production by one tissue or location and action in distinct locations, have been suggested to possess characteristics of ‘hormones’
Mesoscopic Superconducting Disc with Short-Range Columnar Defects
Short-range columnar defects essentially influence the magnetic properties of
a mesoscopic superconducting disc.They help the penetration of vortices into
the sample, thereby decrease the sample magnetization and reduce the upper
critical field. Even the presence of weak defects split a giant vortex state
(usually appearing in a clean disc in the vicinity of the transition to a
normal state) into a number of vortices with smaller topological charges. In a
disc with a sufficient number of strong enough defects vortices are always
placed onto defects. The presence of defects lead to the appearance of
additional magnetization jumps related to the redistribution of vortices which
are already present on the defects and not to the penetration of new vortices.Comment: 14 pgs. RevTex, typos and figures corrected. Submitted to Phys. Rev.
'Bring on the dancing horses!': Ambivalence and class obsession within British media reports of the dressage at London 2012
Design and elaboration of a tractable tricyclic scaffold to synthesize druglike inhibitors of dipeptidyl peptidase-4 (DPP-4), antagonists of the C–C Chemokine Receptor Type 5 (CCR5), and highly potent and selective phosphoinositol-3 Kinase δ (PI3Kδ) inhibitors
A novel molecular scaffold has been synthesized, and its incorporation into new analogues of biologically active molecules across multiple target classes will be discussed. In these studies, we have shown use of the tricyclic scaffold to synthesize potent inhibitors of the serine peptidase DPP-4, antagonists of the CCR5 receptor, and highly potent and selective PI3K δ isoform inhibitors. We also describe the predicted physicochemical properties of the resulting inhibitors and conclude that the tractable molecular scaffold could have potential application in future drug discovery programs
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