Littérature scientifique sur le sujet « Facet extraction »
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Articles de revues sur le sujet "Facet extraction"
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Komamizu, Takahiro, Toshiyuki Amagasa et Hiroyuki Kitagawa. « Facet-value extraction scheme from textual contents in XML data ». International Journal of Web Information Systems 11, no 3 (17 août 2015) : 270–90. http://dx.doi.org/10.1108/ijwis-04-2015-0012.
Texte intégralRésumé :
Purpose – The purpose of this paper is to extract appropriate terms to summarize the current results in terms of the contents of textual facets. Faceted search on XML data helps users find necessary information from XML data by giving attribute–content pairs (called facet-value pair) about the current search results. However, if most of the contents of a facet have longer texts in average (such facets are called textual facets), it is not easy to overview the current results. Design/methodology/approach – The proposed approach is based upon subsumption relationships of terms among the contents of a facet. The subsumption relationship can be extracted using co-occurrences of terms among a number of documents (in this paper, a content of a facet is considered as a document). Subsumption relationships compose hierarchies, and the authors utilize the hierarchies to extract facet-values from textual facets. In the faceted search context, users have ambiguous search demands, they expect broader terms. Thus, we extract high-level terms in the hierarchies as facet-values. Findings – The main findings of this paper are the extracted terms improve users’ search experiences, especially in cases when the search demands are ambiguous. Originality/value – An originality of this paper is the way to utilize the textual contents of XML data for improving users’ search experiences on faceted search. The other originality is how to design the tasks to evaluate exploratory search like faceted search.
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Wei, Xiao, Chenglei Qin et Zheng Xu. « Building the Multidimensional Semantic Index of Webpages for Facet Extraction ». International Journal of Cognitive Informatics and Natural Intelligence 9, no 2 (avril 2015) : 1–23. http://dx.doi.org/10.4018/ijcini.2015040101.
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Faceted search is an efficient search method to use the big data and one of its key issues is to extract facets from unstructured webpages automatically. It is still a problem to extract facets from massive unstructured webpages exactly and automatically. To solve the problem, this paper first proposed a novel index structure of webpages, the Multidimensional Semantic Index (MDSI), which holds rich semantics and are helpful to extract facets. In MDSI, the differently dimensional semantic indexes are bridged by mining the semantic mapping between them. Then, an automatic facet extraction method is proposed by analysing semantic mapping relations in MDSI. At last, to validate the effect of the proposed method, two datasets are constructed and the experimental results show that the proposed method is feasible and comparatively precise.
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Peng, Yu Hui, et Cheng Hui Gao. « A Novel Boundary Extraction Algorithm on Triangular Meshes of STL Model ». Advanced Materials Research 97-101 (mars 2010) : 2929–34. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.2929.
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The generation of boundaries from the triangular meshes of CAD object is very important for successful surface segmentation and subdivision. Considering the characteristics of non-uniformity, sparseness and known facet normal for STL model, which is generated by a CAD system, a new and efficient approach for extracting boundaries on STL model is presented in this paper. Boundaries are classified into sharp feature edge and non-sharp feature edge embedded in the filleting and transitive region. The former is detected based on dihedral edge angle (angle between facets), while the latter is identified by analyzing intrinsic region properties of triangular facets distribution without curvature estimation. By means of unidirectional increment of feature edges, continuous region boundaries are generated. Successful examples are presented to illustrate the feasibility of the proposed algorithm.
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Wang, Wenjian. « Computed-tomography-based precision inspection and shape extraction using facet model ». Optical Engineering 39, no 1 (1 janvier 2000) : 114. http://dx.doi.org/10.1117/1.602343.
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Lin, Yangbin, Cheng Wang, Bili Chen, Dawei Zai et Jonathan Li. « Facet Segmentation-Based Line Segment Extraction for Large-Scale Point Clouds ». IEEE Transactions on Geoscience and Remote Sensing 55, no 9 (septembre 2017) : 4839–54. http://dx.doi.org/10.1109/tgrs.2016.2639025.
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Foks, Nathan Leon, et Yaoguo Li. « Automatic boundary extraction from magnetic field data using triangular meshes ». GEOPHYSICS 81, no 3 (mai 2016) : J47—J60. http://dx.doi.org/10.1190/geo2015-0112.1.
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Boundary extraction is a collective term that we use for the process of extracting the locations of faults, lineaments, and lateral boundaries between geologic units using geophysical observations, such as measurements of the magnetic field. The process typically begins with a preprocessing stage, where the data are transformed to enhance the visual clarity of pertinent features and hence improve the interpretability of the data. The majority of the existing methods are based on raster grid enhancement techniques, and the boundaries are extracted as a series of points or line segments. In contrast, we set out a methodology for boundary extraction from magnetic data, in which we represent the transformed data as a surface in 3D using a mesh of triangular facets. After initializing the mesh, we modify the node locations, such that the mesh smoothly represents the transformed data and that facet edges are aligned with features in the data that approximate the horizontal locations of subsurface boundaries. To illustrate our boundary extraction algorithm, we first apply it to a synthetic data set. We then apply it to identify boundaries in a magnetic data set from the McFaulds Lake area in Ontario, Canada. The extracted boundaries are in agreement with known boundaries and several of the regions that are completely enclosed by extracted boundaries coincide with regions of known mineralization.
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Dulău, Marius, et Florin Oniga. « Obstacle Detection Using a Facet-Based Representation from 3-D LiDAR Measurements ». Sensors 21, no 20 (15 octobre 2021) : 6861. http://dx.doi.org/10.3390/s21206861.
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In this paper, we propose an obstacle detection approach that uses a facet-based obstacle representation. The approach has three main steps: ground point detection, clustering of obstacle points, and facet extraction. Measurements from a 64-layer LiDAR are used as input. First, ground points are detected and eliminated in order to select obstacle points and create object instances. To determine the objects, obstacle points are grouped using a channel-based clustering approach. For each object instance, its contour is extracted and, using an RANSAC-based approach, the obstacle facets are selected. For each processing stage, optimizations are proposed in order to obtain a better runtime. For the evaluation, we compare our proposed approach with an existing approach, using the KITTI benchmark dataset. The proposed approach has similar or better results for some obstacle categories but a lower computational complexity.
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Yang, Deheng, Yadong Li, Xinyi Liu, Yue Cao, Yi Gao, Y. Ron Shen et Wei-Tao Liu. « Facet-specific interaction between methanol and TiO2 probed by sum-frequency vibrational spectroscopy ». Proceedings of the National Academy of Sciences 115, no 17 (9 avril 2018) : E3888—E3894. http://dx.doi.org/10.1073/pnas.1802741115.
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The facet-specific interaction between molecules and crystalline catalysts, such as titanium dioxides (TiO2), has attracted much attention due to possible facet-dependent reactivity. Using surface-sensitive sum-frequency vibrational spectroscopy, we have studied how methanol interacts with different common facets of crystalline TiO2, including rutile(110), (001), (100), and anatase(101), under ambient temperature and pressure. We found that methanol adsorbs predominantly in the molecular form on all of the four surfaces, while spontaneous dissociation into methoxy occurs preferentially when these surfaces become defective. Extraction of Fermi resonance coupling between stretch and bending modes of the methyl group in analyzing adsorbed methanol spectra allows determination of the methanol adsorption isotherm. The isotherms obtained for the four surfaces are nearly the same, yielding two adsorbed Gibbs free energies associated with two different adsorption configurations singled out by ab initio calculations. They are (i) ∼−20 kJ/mol for methanol with its oxygen attached to a low-coordinated surface titanium, and (ii) ∼−5 kJ/mol for methanol hydrogen-bonded to a surface oxygen and a neighboring methanol molecule. Despite similar adsorption energetics, the Fermi resonance coupling strength for adsorbed methanol appears to depend sensitively on the surface facet and coverage.
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Nagendran, Sharan Kumar, Mohd Ashraf Mohamad Ismail et Yan Tung Wen. « Photogrammetry approach on geological plane extraction using CloudCompare FACET plugin and scanline survey ». Bulletin of the Geological Society of Malaysia 68 (31 décembre 2019) : 151–58. http://dx.doi.org/10.7186/bgsm68201916.
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Sano, Hikomaro. « Extraction of facet terms from article titles and their display in tabular form ». Journal of Information Science 17, no 1 (février 1991) : 43–48. http://dx.doi.org/10.1177/016555159101700105.
Texte intégralThèses sur le sujet "Facet extraction"
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PORRINI, RICCARDO. « Construction and Maintenance of Domain Specific Knowledge Graphs for Web Data Integration ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2016. http://hdl.handle.net/10281/126789.
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A Knowledge Graph (KG) is a semantically organized, machine readable collection of types, entities, and relations holding between them. A KG helps in mitigating semantic heterogeneity in scenarios that require the integration of data from independent sources into a so called dataspace, realized through the establishment of mappings between the sources and the KG. Applications built on top of a dataspace provide advanced data access features to end-users based on the representation provided by the KG, obtained through the enrichment of the KG with domain specific facets. A facet is a specialized type of relation that models a salient characteristic of entities of particular domains (e.g., the vintage of wines) from an end-user perspective.
In order to enrich a KG with a salient and meaningful representation of data, domain experts in charge of maintaining the dataspace must be in possess of extensive knowledge about disparate domains (e.g., from wines to football players). From an end-user perspective, the difficulties in the definition of domain specific facets for dataspaces significantly reduce the user-experience of data access features and thus the ability to fulfill the information needs of end-users. Remarkably, this problem has not been adequately studied in the literature, which mostly focuses on the enrichment of the KG with a generalist, coverage oriented, and not domain specific representation of data occurring in the dataspace.
Motivated by this challenge, this dissertation introduces automatic techniques to support domain experts in the enrichment of a KG with facets that provide a domain specific representation of data. Since facets are a specialized type of relations, the techniques proposed in this dissertation aim at extracting salient domain specific relations. The fundamental components of a dataspace, namely the KG and the mappings between sources and KG elements, are leveraged to elicitate such domain specific representation from specialized data sources of the dataspace, and to support domain experts with valuable information for the supervision of the process. Facets are extracted by leveraging already established mappings between specialized sources and the KG. After extraction, a domain specific interpretation of facets is provided by re-using relations already defined in the KG, to ensure tight integration of data. This dissertation introduces also a framework to profile the status of the KG, to support the supervision of domain experts in the above tasks.
Altogether, the contributions presented in this dissertation provide a set of automatic techniques to support domain experts in the evolution of the KG of a dataspace towards a domain specific, end-user oriented representation. Such techniques analyze and exploit the fundamental components of a dataspace (KG, mappings, and source data) with an effectiveness not achievable with state-of-the-art approaches, as shown by extensive evaluations conducted in both synthetic and real world scenarios.
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Low, Boon Kee. « Computer extraction of human faces ». Thesis, De Montfort University, 1999. http://hdl.handle.net/2086/10668.
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Due to the recent advances in visual communication and face recognition technologies, automatic face detection has attracted a great deal of research interest. Being a diverse problem, the development of face detection research has comprised contributions from researchers in various fields of sciences. This thesis examines the fundamentals of various face detection techniques implemented since the early 70's. Two groups of techniques are identified based on their approach in applying face knowledge as a priori: feature-based and image-based. One of the problems faced by the current feature-based techniques, is the lack of costeffective segmentation algorithms that are able to deal with issues such as background and illumination variations. As a result a novel facial feature segmentation algorithm is proposed in this thesis. The algorithm aims to combine spatial and temporal information using low cost techniques. In order to achieve this, an existing motion detection technique is analysed and implemented with a novel spatial filter, which itself is proved robust for segmentation of features in varying illumination conditions. Through spatio-temporal information fusion, the algorithm effectively addresses the background and illumination problems among several head and shoulder sequences. Comparisons of the algorithm with existing motion and spatial techniques establishes the efficacy of the combined approach.
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PANA-TALPEANU, RADU-MIHAI. « Trajectory extraction for automatic face sketching ». Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-142429.
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This project consists of a series of algorithms employed to obtain a simplistic but realistic representation of a human face. The final goal is for the sketch to be drawn onto paper by a robotic arm with a gripper holding a drawing instrument. The end application is mostly geared towards entertainment and combines the fields of human-machine interaction, machine learning and image processing. The first part focuses on manipulating an input digital image in order to obtain trajectories of a suitable format for the robot to process. Different techniques are presented, tested and compared, such as edge extraction, landmark detection, spline generation and principal component analysis. Results showed that an edge detector yields too many lines, while the generative spline method leads to overly simplistic faces. The best facial depiction was obtained by combining landmark localization with edge detection. The trajectories outputted by the different techniques are passed to the arm through the high level interface provided by ROS, the Robot Operating System and then drawn on paper.Detta projekt består av en serie av algoritmer som används för att erhålla en förenklad men realistisk återgivning av ett mänskligt ansikte. Det slutgiltiga målet är att skissen ska ritas på papper av en robotarm med en gripare som håller ett ritinstrument. Tillämpningen är nöjesorienterad och kombinerar områdena människamaskin- interaktion, maskininlärning och bildbehandling. Den första delen fokuserar på att manipulera en mottagen digital bild så att banor i ett format lämpligt för roboten erhålls. Olika tekniker presenteras, testas och jämförs såsom kantdetektion, igenkänning av landmärke, spline-generering och principalkomponentanalys. Resultaten visade att en kantdetektor ger alltför många linjer och att spline-genererings-metoden leder till alltför förenklade ansikten. Den bästa ansiktsskildringen erhölls genom att kombinera lokalisering av landmärke med kantdetektering. De banor som erhållits genom de olika teknikerna överförs till armen genom ett högnivågränssnitt till ROS, Robot Operating System och sedan ritas på papper.
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Nguyen, Huu-Tuan. « Contributions to facial feature extraction for face recognition ». Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT034/document.
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La tâche la plus délicate d'un système de reconnaissance faciale est la phase d'extraction de caractéristiques significatives et discriminantes. Dans le cadre de cette thèse, nous nous sommes focalisés sur cette tâche avec comme objectif l'élaboration d'une représentation de visage robuste aux variations majeures suivantes: variations d'éclairage, de pose, de temps, images de qualité différentes (vidéosurveillance). Par ailleurs, nous avons travaillé également dans une optique de traitement temps réel. Tout d'abord, en tenant compte des caractéristiques d'orientation des traits principaux du visages (yeux, bouche), une nouvelle variante nommée ELBP de célèbre descripteur LBP a été proposée. Elle s'appuie sur les informations de micro-texture contenues dans une ellipse horizontale. Ensuite, le descripteur EPOEM est construit afin de tenir compte des informations d'orientation des contours. Puis un descripteur nommée PLPQMC qui intégre des informations obtenues par filtrage monogénique dans le descripteur LPQ est proposé. Enfin le descripteur LPOG intégrant des informations de gradient est présenté. Chacun des descripteurs proposés est testé sur les 3 bases d'images AR, FERET et SCface. Il en résulte que les descripteurs PLPQMC et LPOG sont les plus performants et conduisent à des taux de reconnaissance comparables voire supérieur à ceux des meilleurs méthodes de l'état de l'artCentered around feature extraction, the core task of any Face recognition system, our objective is devising a robust facial representation against major challenges, such as variations of illumination, pose and time-lapse and low resolution probe images, to name a few. Besides, fast processing speed is another crucial criterion. Towards these ends, several methods have been proposed through out this thesis. Firstly, based on the orientation characteristics of the facial information and important features, like the eyes and mouth, a novel variant of LBP, referred as ELBP, is designed for encoding micro patterns with the usage of an horizontal ellipse sample. Secondly, ELBP is exploited to extract local features from oriented edge magnitudes images. By this, the Elliptical Patterns of Oriented Edge Magnitudes (EPOEM) description is built. Thirdly, we propose a novel feature extraction method so called Patch based Local Phase Quantization of Monogenic components (PLPQMC). Lastly, a robust facial representation namely Local Patterns of Gradients (LPOG) is developed to capture meaningful features directly from gradient images. Chiefs among these methods are PLPQMC and LPOG as they are per se illumination invariant and blur tolerant. Impressively, our methods, while offering comparable or almost higher results than that of existing systems, have low computational cost and are thus feasible to deploy in real life applications
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Gunn, Steve R. « Dual active contour models for image feature extraction ». Thesis, University of Southampton, 1996. https://eprints.soton.ac.uk/250089/.
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Active contours are now a very popular technique for shape extraction, achieved by minimising a suitably formulated energy functional. Conventional active contour formulations suffer difficulty in appropriate choice of an initial contour and values of parameters. Recent approaches have aimed to resolve these problems, but can compromise other performance aspects. To relieve the problem in initialisation, an evolutionary dual active contour has been developed, which is combined with a local shape model to improve the parameterisation. One contour expands from inside the target feature, the other contracts from the outside. The two contours are inter-linked to provide a balanced technique with an ability to reject weak’local energy minima. Additionally a dual active contour configuration using dynamic programming has been developed to locate a global energy minimum and complements recent approaches via simulated annealing and genetic algorithms. These differ from conventional evolutionary approaches, where energy minimisation may not converge to extract the target shape, in contrast with the guaranteed convergence of a global approach. The new techniques are demonstrated to extract successfully target shapes in synthetic and real images, with superior performance to previous approaches. The new technique employing dynamic programming is deployed to extract the inner face boundary, along with a conventional normal-driven contour to extract the outer face boundary. Application to a database of 75 subjects showed that the outer contour was extracted successfully for 96% of the subjects and the inner contour was successful for 82%. This application highlights the advantages new dual active contour approaches for automatic shape extraction can confer.
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Urbansky, David. « WebKnox : Web Knowledge Extraction ». Master's thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-23766.
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This thesis focuses on entity and fact extraction from the web. Different knowledge representations and techniques for information extraction are discussed before the design for a knowledge extraction system, called WebKnox, is introduced. The main contribution of this thesis is the trust ranking of extracted facts with a self-supervised learning loop and the extraction system with its composition of known and refined extraction algorithms. The used
techniques show an improvement in precision and recall in most of the matters for entity and fact extractions compared to the chosen baseline approaches.
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Gao, Jiangning. « 3D face recognition using multicomponent feature extraction from the nasal region and its environs ». Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707585.
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This thesis is dedicated to extracting expression robust features for 3D face recognition. The use of 3D imaging enables the extraction of discriminative features that can significantly improve the recognition performance due to the availability of facial surface information such as depth, surface normals and curvature. Expression robust analysis using information from both depth and surface normals is investigated by dividing the main facial region into patches of different scales. The nasal region and adjoining parts of the cheeks are utilized as they are more consistent over different expressions and are hard to deliberately occlude. In addition, in comparison with other parts of the face, these regions have a high potential to produce discriminative features for recognition and overcome pose variations. An overview and classification methodology of the widely used 3D face databases are first introduced to provide an appropriate reference for 3D face database selection. Using the FRGC and Bosphorus databases, a low complexity pattern rejector for expression robust 3D face recognition is proposed by matching curves on the nasal and its environs, which results in a low-dimension feature set of only 60 points. To extract discriminative features more locally, a novel multi-scale and multi-component local shape descriptor is further proposed, which achieves more competitive performances under the identification and verification scenarios. In contrast with many of the existing work on 3D face recognition that consider captures obtained with laser scanners or structured light, this thesis also investigates applications to reconstructed 3D captures from lower cost photometric stereo imaging systems that have applications in real-world situations. To this end, the performance of the expression robust face recognition algorithms developed for captures from laser scanners are further evaluated on the Photoface database, which contains naturalistic expression variations. To improve the recognition performance of all types of 3D captures, a universal landmarking algorithm is proposed that makes uses of different components of the surface normals. Using facial profile signatures and thresholded surface normal maps, facial roll and yaw rotations are calibrated and five main landmarks are robustly detected on the well-aligned 3D nasal region. The landmarking results show that the detected landmarks demonstrate high within-class consistency and can achieve good recognition performances under different expressions. This is also the first landmarking work specifically developed for the reconstructed 3D captures from photometric stereo imaging systems.
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Al-Qatawneh, Sokyna M. S. « 3D Facial Feature Extraction and Recognition. An investigation of 3D face recognition : correction and normalisation of the facial data, extraction of facial features and classification using machine learning techniques ». Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4876.
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Face recognition research using automatic or semi-automatic techniques has emerged over the last two decades. One reason for growing interest in this topic is the wide range of possible applications for face recognition systems. Another reason is the emergence of affordable hardware, supporting digital photography and video, which have made the acquisition of high-quality and high resolution 2D images much more ubiquitous. However, 2D recognition systems are sensitive to subject pose and illumination variations and 3D face recognition which is not directly affected by such environmental changes, could be used alone, or in combination with 2D recognition. Recently with the development of more affordable 3D acquisition systems and the availability of 3D face databases, 3D face recognition has been attracting interest to tackle the limitations in performance of most existing 2D systems. In this research, we introduce a robust automated 3D Face recognition system that implements 3D data of faces with different facial expressions, hair, shoulders, clothing, etc., extracts features for discrimination and uses machine learning techniques to make the final decision. A novel system for automatic processing for 3D facial data has been implemented using multi stage architecture; in a pre-processing and registration stage the data was standardized, spikes were removed, holes were filled and the face area was extracted. Then the nose region, which is relatively more rigid than other facial regions in an anatomical sense, was automatically located and analysed by computing the precise location of the symmetry plane. Then useful facial features and a set of effective 3D curves were extracted. Finally, the recognition and matching stage was implemented by using cascade correlation neural networks and support vector machine for classification, and the nearest neighbour algorithms for matching. It is worth noting that the FRGC data set is the most challenging data set available supporting research on 3D face recognition and machine learning techniques are widely recognised as appropriate and efficient classification methods.
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Benn, David E. « Model-based feature extraction and classification for automatic face recognition ». Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324811.
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Jung, Sung Uk. « On using gait to enhance face extraction for visual surveillance ». Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/340358/.
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Visual surveillance finds increasing deployment for monitoring urban environments. Operators need to be able to determine identity from surveillance images and often use face recognition for this purpose. Unfortunately, the quality of the recorded imagery can be insufficient for this task. This study describes a programme of research aimed to ameliorate this limitation. Many face biometrics systems use controlled environments where subjects are viewed directly facing the camera. This is less likely to occur in surveillance environments, so it is necessary to handle pose variations of the human head, low frame rate, and low resolution input images. We describe the first use of gait to enable face acquisition and recognition, by analysis of 3D head motion and gait trajectory, with super-resolution analysis. The face extraction procedure consists of three stages: i) head pose estimation by a 3D ellipsoidal model; ii) face region extraction by using a 2D or a 3D gait trajectory; and iii) frontal face extraction and reconstruction by estimating head pose and using super-resolution techniques. The head pose is estimated by using a 3D ellipsoidal model and non-linear optimisation. Region- and distance-based feature refinement methods are used and a direct mapping from the 2D image coordinate to the object coordinate is developed. In face region extraction the potential face region is extracted based on the 2D gait trajectory model when a person walks towards a camera. We model a looming field and show how this field affects the image sequences of the human walking. By fitting a 2D gait trajectory model the face region can then be tracked. For the general case of the human walking a 3D gait trajectory model and heel strike positions are used to extract the face region in 3D space. Wavelet decomposition is used to detect the gait cycle and a new heel strike detection method is developed. In face extraction a high resolution frontal face image is reconstructed with low resolution face images by analysing super-resolution. Based on the head pose and 3D ellipsoidal model the invalid low resolution face images are filtered and the frontal view face is reconstructed. By adapting the existing super-resolution the high resolution frontal face image can be synthesised, which is demonstrated to be suitable for face recognition. The contributions of this research include the construction of a 3D model for pose estimation from planar imagery and the first use of gait information to enhance the face extraction and recognition process allowing for deployment in surveillance scenarios.
Livres sur le sujet "Facet extraction"
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Low, Boon Kee. Computer extraction of human faces. Leicester : De Montfort University, 1999.
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Tonelli, Paolo, dir. Il giudizio nell'estrazione del terzo molare inferiore. Florence : Firenze University Press, 2022. http://dx.doi.org/10.36253/978-88-5518-576-9.
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The scientific literature and clinical dental practice have in the extraction of the lower third molar an area of wide interest. In fact, parallel to the presence of prejudices and false beliefs on the part of patients, there is also a great variability of scientific opinions among professionals in the field, both in relation to the indications for extraction, diagnostic aids, and intra- and post-operative management. Our text aims to merge the awareness given by clinical experience with the knowledge of an evidence-based dental culture, proposing itself as a stimulus for in-depth study for students, professionals and enthusiasts of the subject. The multimedia digital resources (photos and videos) of some dental procedures can be freely consulted via the QR code on the cover.
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Powers, Shawn M., et Michael Jablonski. Google, Information, and Power. University of Illinois Press, 2017. http://dx.doi.org/10.5406/illinois/9780252039126.003.0004.
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This chapter examines Google's aims to dominate the global market for information services and data. Drawing from the suggestion that “information is the new oil of the Internet and the currency of the digital world,” it explores how Google's various endeavors seek to control each facet of the data market: data production, data extraction, data refinement, data infrastructure and distribution, and demand. It shows that there is no equivalent company that has ever been capable of dominance in each facet of the oil economy to the extent that Google leads in the data economy. The chapter also discusses the commodification of information in the modern internet economy and argues that Google's interest in internet freedom and connectivity lies in the fact that its survival (in the political economy sense of the word) depends on getting more and more people online to use its complimentary services.
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Lebdioui, Amir. Are we measuring natural resource wealth correctly ? A reconceptualization of natural resource value in the era of climate change. 18e éd. UNU-WIDER, 2021. http://dx.doi.org/10.35188/unu-wider/2021/952-5.
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Underlying the management of revenues from natural resource extraction is a set of assumptions about how abundant and how valuable these resources are. Nevertheless, existing approaches to measuring the value of extractive resources are seriously flawed. This paper proposes two avenues for improving them. It explains how a multidimensional approach to measuring resource wealth can be used to identify the policy challenges that a country might face as it sets out its strategy for managing extractive revenues. It also provides a rethinking of the valuation of extractive wealth by integrating environmental considerations. Extractive activities can at times incur a great loss of (renewable) opportunity income, either directly or indirectly, because of their environmental impact. By analysing a range of examples from across the globe, this paper extracts key lessons on the true value of extractives and why it matters for policy makers, civil society, and international donors today.
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Jaskoski, Maiah. The Politics of Extraction. Oxford University PressNew York, 2022. http://dx.doi.org/10.1093/oso/9780197568927.001.0001.
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Abstract In the face of new extraction, communities in Latin America’s hydrocarbon and mining regions use participatory institutions to challenge extraction. In some cases, communities act within the formal participatory spaces, while in others, they organize “around” or “in reaction to” the institutions, using participatory procedures as a focal point for the escalation of conflict. Communities select their strategies in response to the participatory challenges they confront. Those challenges are associated with contestation over the boundaries that determine access to the participatory institutions. Contestation over the line between subnational authority vis-à-vis central-state jurisdictions heightens communities’ challenge of initiating a participatory process. Disagreement over the territorial delineation of communities impacted by planned extraction creates the challenge of gaining inclusion in participatory events, for formally nonimpacted communities. Finally, disputes over the boundary that sets representatives of an affected community apart from the community at large intensify the community’s challenge of conveying a position on extraction. This analysis of thirty major extractive conflicts in Bolivia, Colombia, and Peru in the 2000s and 2010s examines community uses of public hearings built into environmental licensing, state-led prior consultations with native communities, and local popular consultations, or referenda.
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Nguyen, Duy Phuc. An FPGA implementation of face detection and lip feature extraction. 2005.
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Nguyen, Duy Phuc. An FPGA implementation of face detection and lip feature extraction. 2005.
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Linguistics, Association for Computational. Proceedings of the Fifth Workshop on Fact Extraction and VERification (FEVER). Association for Computational Linguistics, 2022.
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Fancourt, Daisy. Fact file 2 : Dentistry. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198792079.003.0015.
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Dentistry involves the study, diagnosis, prevention, and/or treatment of diseases, disorders, and conditions of the oral cavity, including the teeth, gums, and tissues. Dentistry is thought to be one of the first areas of specialization to emerge from medicine, with evidence of drilled teeth dating back 9,000 years. The most common conditions treated within dentistry involve tooth decay (dental caries) and gum disease (periodontal disease), with common dental procedures including x-rays, restorative treatments (such as fillings, crowns, and bridges), prosthetics (dentures), orthodontics (such as teeth braces), tooth extraction and endodontic (root canal) therapy. Dentistry also involves public health work such as the encouragement of oral disease prevention through dental hygiene and check-ups....
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Guide for conducting treatability studies under CERCLA : Soil vapor extraction : quick reference fact sheet. Cincinnati, OH : U.S. Environmental Protection Agency, Center for Environmental Research Information, 1991.
Trouver le texte intégralChapitres de livres sur le sujet "Facet extraction"
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Xue, Dashen, Zhaohui Li et Shenglan Hao. « Face Feature Extraction and Face Recognition ». Dans Lecture Notes in Electrical Engineering, 57–62. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-27287-5_10.
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Rupprecht, Dominik, Sebastian Hesse et Rainer Blum. « Automatic Face Feature Points Extraction ». Dans Digital Human Modeling, 186–94. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-21799-9_21.
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Fang, Hui, et Nicholas Costen. « Behavioral Consistency Extraction for Face Verification ». Dans Cross-Modal Analysis of Speech, Gestures, Gaze and Facial Expressions, 291–305. Berlin, Heidelberg : Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03320-9_27.
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Seifert, Christin, Michael Granitzer, Patrick Höfler, Belgin Mutlu, Vedran Sabol, Kai Schlegel, Sebastian Bayerl, Florian Stegmaier, Stefan Zwicklbauer et Roman Kern. « Crowdsourcing Fact Extraction from Scientific Literature ». Dans Human-Computer Interaction and Knowledge Discovery in Complex, Unstructured, Big Data, 160–72. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-39146-0_15.
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Usha, Kamale, Beecha Sudeepthi, Devarakonda Mahathi et Pillarisetti Shravya. « Face Mask Detection Using Feature Extraction ». Dans Data Engineering and Communication Technology, 437–47. Singapore : Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0081-4_46.
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Paisitkriangkrai, Sakrapee, Chunhua Shen et Jian Zhang. « Face Detection with Effective Feature Extraction ». Dans Computer Vision – ACCV 2010, 460–70. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19318-7_36.
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Yoo, Tae-Woong, et Il-Seok Oh. « Extraction of face region and features based on chromatic properties of human faces ». Dans Lecture Notes in Computer Science, 637–45. Berlin, Heidelberg : Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/3-540-61532-6_54.
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Guyot, Laurent, Pierre Seguin et Hervé Benateau. « Extractions dentaires simples ». Dans Techniques en chirurgie maxillo-faciale et plastique de la face, 11–13. Paris : Springer Paris, 2010. http://dx.doi.org/10.1007/978-2-8178-0073-8_4.
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Erol, A., U. Halici et G. Ongun. « Feature Selective Filtering for Ridge Extraction ». Dans INTELLIGENT BIOMETRIC TECHNIQUES in FINGERPRINT and FACE RECOGNITION, 193–215. Boca Raton : Routledge, 2022. http://dx.doi.org/10.1201/9780203750520-6.
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Lin, Yang, Pengyu Huang, Yuxuan Lai, Yansong Feng et Dongyan Zhao. « Evidence Distilling for Fact Extraction and Verification ». Dans Natural Language Processing and Chinese Computing, 211–22. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-32233-5_17.
Texte intégralActes de conférences sur le sujet "Facet extraction"
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Kong, Weize, et James Allan. « Precision-Oriented Query Facet Extraction ». Dans CIKM'16 : ACM Conference on Information and Knowledge Management. New York, NY, USA : ACM, 2016. http://dx.doi.org/10.1145/2983323.2983824.
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Wei, Xiao, Xiangfeng Luo et Qing Li. « Automatic Facet Extraction Based on Multidimensional Semantic Index ». Dans 2012 Eighth International Conference on Semantics, Knowledge and Grids (SKG). IEEE, 2012. http://dx.doi.org/10.1109/skg.2012.22.
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Samarinas, Chris, Arkin Dharawat et Hamed Zamani. « Revisiting Open Domain Query Facet Extraction and Generation ». Dans ICTIR '22 : The 2022 ACM SIGIR International Conference on the Theory of Information Retrieval. New York, NY, USA : ACM, 2022. http://dx.doi.org/10.1145/3539813.3545138.
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Komamizu, Takahiro, Toshiyuki Amagasa et Hiroyuki Kitagawa. « Frequent-Pattern Based Facet Extraction from Graph Data ». Dans 2014 17th International Conference on Network-Based Information Systems (NBiS). IEEE, 2014. http://dx.doi.org/10.1109/nbis.2014.77.
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Dakka, Wisam, et Panagiotis G. Ipeirotis. « Automatic Extraction of Useful Facet Hierarchies from Text Databases ». Dans 2008 IEEE 24th International Conference on Data Engineering (ICDE 2008). IEEE, 2008. http://dx.doi.org/10.1109/icde.2008.4497455.
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Zhao, Ping, Wenzhen Zhao, Zhenyun Duan et Wenhui Zhao. « Subpixel-precise Edge Extraction Algorithm Based on Facet Model ». Dans 2012 Fourth International Conference on Computational and Information Sciences (ICCIS). IEEE, 2012. http://dx.doi.org/10.1109/iccis.2012.307.
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Komamizu, Takahiro, Toshiyuki Amagasa et Hiroyuki Kitagawa. « A scheme of automated object and facet extraction for faceted search over XML data ». Dans the 18th International Database Engineering & Applications Symposium. New York, New York, USA : ACM Press, 2014. http://dx.doi.org/10.1145/2628194.2628241.
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Brown, Philip E., Yaron Kanza et Velin Kounev. « Height and Facet Extraction from LiDAR Point Cloud for Automatic Creation of 3D Building Models ». Dans SIGSPATIAL '19 : 27th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems. New York, NY, USA : ACM, 2019. http://dx.doi.org/10.1145/3347146.3359372.
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Grammel, Birgit, et Stefan Kastenholz. « A generic traceability framework for facet-based traceability data extraction in model-driven software development ». Dans the 6th ECMFA Traceability Workshop. New York, New York, USA : ACM Press, 2010. http://dx.doi.org/10.1145/1814392.1814394.
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Dougrez-Lewis, John, Elena Kochkina, Miguel Arana-Catania, Maria Liakata et Yulan He. « PHEMEPlus : Enriching Social Media Rumour Verification with External Evidence ». Dans Proceedings of the Fifth Fact Extraction and VERification Workshop (FEVER). Stroudsburg, PA, USA : Association for Computational Linguistics, 2022. http://dx.doi.org/10.18653/v1/2022.fever-1.6.
Texte intégralRapports d'organisations sur le sujet "Facet extraction"
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Rentería Palomares, Zaira, Jorge Gutiérrez García et Daniel Perdomo Rodríguez. Digitalization in the Extractive Sector : A Comparative Analysis of the Andean Region. Inter-American Development Bank, décembre 2022. http://dx.doi.org/10.18235/0004675.
Texte intégralRésumé :
Global efforts to achieve the climate goals specified in the Paris Agreement pose major challenges for the global production system, because demand for clean fuels, metals, and minerals will increase considerably in the coming decades. This trend is the main driver for extractive companies transformations of their production systems to maintain their profitability and operability in the face of an increasingly stringent context in economic, environmental, and social terms. Hence, the adoption of digital technologies appears as a unique opportunity that would enable the industry to meet the challenges posed by the energy transition that is looming. In this challenging context, companies in the extractive sector have started to rethink not only their internal operations, but also the ways in which they interact with communities, the environment, and public opinion.
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Doo, Johnny. Unsettled Issues Concerning eVTOL for Rapid-response, On-demand Firefighting. SAE International, août 2021. http://dx.doi.org/10.4271/epr2021017.
Texte intégralRésumé :
Recent advancements of electric vertical take-off and landing (eVTOL) aircraft have generated significant interest within and beyond the traditional aviation industry, and many novel applications have been identified and are in development. One promising application for these innovative systems is in firefighting, with eVTOL aircraft complementing current firefighting capabilities to help save lives and reduce fire-induced damages. With increased global occurrences and scales of wildfires—not to mention the issues firefighters face during urban and rural firefighting operations daily—eVTOL technology could offer timely, on-demand, and potentially cost-effective aerial mobility capabilities to counter these challenges. Early detection and suppression of wildfires could prevent many fires from becoming large-scale disasters. eVTOL aircraft may not have the capacity of larger aerial assets for firefighting, but targeted suppression, potentially in swarm operations, could be valuable. Most importantly, on-demand aerial extraction of firefighters can be a crucial benefit during wildfire control operations. Aerial firefighter dispatch from local fire stations or vertiports can result in more effective operations, and targeted aerial fire suppression and civilian extraction from high-rise buildings could enhance capabilities significantly. There are some challenges that need to be addressed before the identified capabilities and benefits are realized at scale, including the development of firefighting-specific eVTOL vehicles; sense and avoid capabilities in complex, smoke-inhibited environments; autonomous and remote operating capabilities; charging system compatibility and availability; operator and controller training; dynamic airspace management; and vehicle/fleet logistics and support. Acceptance from both the first-responder community and the general public is also critical for the successful implementation of these new capabilities. The purpose of this report is to identify the benefits and challenges of implementation, as well as some of the potential solutions. Based on the rapid development progress of eVTOL aircraft and infrastructures with proactive community engagement, it is envisioned that these challenges can be addressed soon. NOTE: SAE EDGE™ Research Reports are intended to identify and illuminate key issues in emerging, but still unsettled, technologies of interest to the mobility industry. The goal of SAE EDGE™ Research Reports is to stimulate discussion and work in the hope of promoting and speeding resolution of identified issues. These reports are not intended to resolve the challenges they identify or close any topic to further scrutiny.
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Shenker, Moshe, Paul R. Bloom, Abraham Shaviv, Adina Paytan, Barbara J. Cade-Menun, Yona Chen et Jorge Tarchitzky. Fate of Phosphorus Originated from Treated Wastewater and Biosolids in Soils : Speciation, Transport, and Accumulation. United States Department of Agriculture, juin 2011. http://dx.doi.org/10.32747/2011.7697103.bard.
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Beneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levelsBeneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levels that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction.
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Rahmé, Marianne, et Alex Walsh. Corruption Challenges and Responses in the Democratic Republic of Congo. Institute of Development Studies, janvier 2022. http://dx.doi.org/10.19088/k4d.2022.093.
Texte intégralRésumé :
The Democratic Republic of the Congo (DRC) consistently scores in the lowest rungs of global indexes on corruption, integrity and wider governance standards. Indeed, corruption of different sorts pervades public and corporate life, with strong ramifications for human development. Although the DRC is one of the richest countries in the world in terms of natural resources, its people are among the globe’s poorest.Corruption in the extractive industries (minerals and oil) is particularly problematic in terms of scale and its centrality to a political economy that maintains elites and preserves the highly inequitable outcomes for the majority. The politico-economic elites of the DRC, such as former President Joseph Kabila, are reportedly significant perpetrators but multinationals seeking valuable minerals or offering financial services are also allegedly deeply involved. Corruption is therefore a problem with national and international roots.Despite national and international initiatives, levels of corruption have proven very stubborn for at least the last 20 years, for various reasons. It is a structural and not just a legal issue. It is deeply entrenched in the country’s political economy and is driven both by domestic clientelism and the fact that multinationals buy into corrupt deals. This rapid review therefore seeks to find out the Corruption challenges and responses in the Democratic Republic of Congo.Grand level corruption shades down into the meso-level, where for instance, mineral laden trucks are systematically under-weighted with the collusion of state officials. With severe shortfalls in public funding, certain public services, such as education, are supported by informal payments. Other instances of petty corruption facilitate daily access to goods and services. At this level, there are arguments against counting such practices as forms of corruption and instead as necessary survival practices.To address the challenge of corruption, the DRC is equipped with a legal system that is of mixed strengths and an institutional arsenal that has made limited progress. International programming in integrity and anti-corruption represents a significant proportion of support to the DRC but much less than humanitarian and governance sectors. The leading international partners in this regard are the EU, US, UNDP, UK, African Development Bank, Germany and Sweden. These partners conduct integrity programming in general governance issues, as well as in the mineral and forest sectors.The sources used in this rapid review are gender blind and converge on a very negative picture The literature ranges from the academic and practitioner to the journalistic and investigative, and taken as a whole, is of good quality, drawing on different types of evidence including perceptions and qualitative in-country research. The sources are mostly in English with two in French.
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Lahav, Ori, Albert Heber et David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, mars 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
Texte intégralRésumé :
The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.
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Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion et Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, octobre 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
Texte intégralRésumé :
Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.