WorldWideScience

Sample records for silicon atoms-phosphorus neighbors

  1. NeighborHood

    OpenAIRE

    Corominola Ocaña, Víctor

    2015-01-01

    NeighborHood és una aplicació basada en el núvol, adaptable a qualsevol dispositiu (mòbil, tablet, desktop). L'objectiu d'aquesta aplicació és poder permetre als usuaris introduir a les persones del seu entorn més immediat i que aquestes persones siguin visibles per a la resta d'usuaris. NeighborHood es una aplicación basada en la nube, adaptable a cualquier dispositivo (móvil, tablet, desktop). El objetivo de esta aplicación es poder permitir a los usuarios introducir a las personas de su...

  2. Neighbors United for Health

    Science.gov (United States)

    Westhoff, Wayne W.; Corvin, Jaime; Virella, Irmarie

    2009-01-01

    Modeled upon the ecclesiastic community group concept of Latin America to unite and strengthen the bond between the Church and neighborhoods, a community-based organization created Vecinos Unidos por la Salud (Neighbors United for Health) to bring health messages into urban Latino neighborhoods. The model is based on five tenants, and incorporates…

  3. Neighboring and Urbanism: Commonality versus Friendship.

    Science.gov (United States)

    Silverman, Carol J.

    1986-01-01

    Examines a dimension of neighboring that need not assume friendship as the role model. When the model assumes only a sense of connectedness as defining neighboring, then the residential correlation, shown in many studies between urbanism and neighboring, disappears. Theories of neighboring, study variables, methods, and analysis are discussed.…

  4. Nearest neighbors by neighborhood counting.

    Science.gov (United States)

    Wang, Hui

    2006-06-01

    Finding nearest neighbors is a general idea that underlies many artificial intelligence tasks, including machine learning, data mining, natural language understanding, and information retrieval. This idea is explicitly used in the k-nearest neighbors algorithm (kNN), a popular classification method. In this paper, this idea is adopted in the development of a general methodology, neighborhood counting, for devising similarity functions. We turn our focus from neighbors to neighborhoods, a region in the data space covering the data point in question. To measure the similarity between two data points, we consider all neighborhoods that cover both data points. We propose to use the number of such neighborhoods as a measure of similarity. Neighborhood can be defined for different types of data in different ways. Here, we consider one definition of neighborhood for multivariate data and derive a formula for such similarity, called neighborhood counting measure or NCM. NCM was tested experimentally in the framework of kNN. Experiments show that NCM is generally comparable to VDM and its variants, the state-of-the-art distance functions for multivariate data, and, at the same time, is consistently better for relatively large k values. Additionally, NCM consistently outperforms HEOM (a mixture of Euclidean and Hamming distances), the "standard" and most widely used distance function for multivariate data. NCM has a computational complexity in the same order as the standard Euclidean distance function and NCM is task independent and works for numerical and categorical data in a conceptually uniform way. The neighborhood counting methodology is proven sound for multivariate data experimentally. We hope it will work for other types of data.

  5. Extrinsic doping in silicon revisited

    KAUST Repository

    Schwingenschlögl, Udo

    2010-06-17

    Both n-type and p-type doping of silicon is at odds with the charge transfer predicted by Pauling electronegativities and can only be reconciled if we no longer regarding dopant species as isolated atoms but rather consider them as clusters consisting of the dopant and its four nearest neighbor silicon atoms. The process that gives rise to n-type and p-type effects is the charge redistribution that occurs between the dopant and its neighbors, as we illustrate here using electronic structure calculations. This view point is able to explain why conventional substitutional n-type doping of carbon has been so difficult.

  6. Extrinsic doping in silicon revisited

    KAUST Repository

    Schwingenschlö gl, Udo; Chroneos, Alexander; Grimes, R. W.; Schuster, Cosima

    2010-01-01

    Both n-type and p-type doping of silicon is at odds with the charge transfer predicted by Pauling electronegativities and can only be reconciled if we no longer regarding dopant species as isolated atoms but rather consider them as clusters consisting of the dopant and its four nearest neighbor silicon atoms. The process that gives rise to n-type and p-type effects is the charge redistribution that occurs between the dopant and its neighbors, as we illustrate here using electronic structure calculations. This view point is able to explain why conventional substitutional n-type doping of carbon has been so difficult.

  7. Identifying influential neighbors in animal flocking.

    Directory of Open Access Journals (Sweden)

    Li Jiang

    2017-11-01

    Full Text Available Schools of fish and flocks of birds can move together in synchrony and decide on new directions of movement in a seamless way. This is possible because group members constantly share directional information with their neighbors. Although detecting the directionality of other group members is known to be important to maintain cohesion, it is not clear how many neighbors each individual can simultaneously track and pay attention to, and what the spatial distribution of these influential neighbors is. Here, we address these questions on shoals of Hemigrammus rhodostomus, a species of fish exhibiting strong schooling behavior. We adopt a data-driven analysis technique based on the study of short-term directional correlations to identify which neighbors have the strongest influence over the participation of an individual in a collective U-turn event. We find that fish mainly react to one or two neighbors at a time. Moreover, we find no correlation between the distance rank of a neighbor and its likelihood to be influential. We interpret our results in terms of fish allocating sequential and selective attention to their neighbors.

  8. Identifying influential neighbors in animal flocking.

    Science.gov (United States)

    Jiang, Li; Giuggioli, Luca; Perna, Andrea; Escobedo, Ramón; Lecheval, Valentin; Sire, Clément; Han, Zhangang; Theraulaz, Guy

    2017-11-01

    Schools of fish and flocks of birds can move together in synchrony and decide on new directions of movement in a seamless way. This is possible because group members constantly share directional information with their neighbors. Although detecting the directionality of other group members is known to be important to maintain cohesion, it is not clear how many neighbors each individual can simultaneously track and pay attention to, and what the spatial distribution of these influential neighbors is. Here, we address these questions on shoals of Hemigrammus rhodostomus, a species of fish exhibiting strong schooling behavior. We adopt a data-driven analysis technique based on the study of short-term directional correlations to identify which neighbors have the strongest influence over the participation of an individual in a collective U-turn event. We find that fish mainly react to one or two neighbors at a time. Moreover, we find no correlation between the distance rank of a neighbor and its likelihood to be influential. We interpret our results in terms of fish allocating sequential and selective attention to their neighbors.

  9. Silicone metalization

    Energy Technology Data Exchange (ETDEWEB)

    Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  10. Density of oxidation-induced stacking faults in damaged silicon

    NARCIS (Netherlands)

    Kuper, F.G.; Hosson, J.Th.M. De; Verwey, J.F.

    1986-01-01

    A model for the relation between density and length of oxidation-induced stacking faults on damaged silicon surfaces is proposed, based on interactions of stacking faults with dislocations and neighboring stacking faults. The model agrees with experiments.

  11. Recrafting the Neighbor-Joining Method

    DEFF Research Database (Denmark)

    Mailund; Brodal, Gerth Stølting; Fagerberg, Rolf

    2006-01-01

    Background: The neighbor-joining method by Saitou and Nei is a widely used method for constructing phylogenetic trees. The formulation of the method gives rise to a canonical Θ(n3) algorithm upon which all existing implementations are based. Methods: In this paper we present techniques for speeding...... up the canonical neighbor-joining method. Our algorithms construct the same phylogenetic trees as the canonical neighbor-joining method. The best-case running time of our algorithms are O(n2) but the worst-case remains O(n3). We empirically evaluate the performance of our algoritms on distance...... matrices obtained from the Pfam collection of alignments. Results: The experiments indicate that the running time of our algorithms evolve as Θ(n2) on the examined instance collection. We also compare the running time with that of the QuickTree tool, a widely used efficient implementation of the canonical...

  12. The clinic as a good corporate neighbor.

    Science.gov (United States)

    Sass, Hans-Martin

    2013-02-01

    Clinics today specialize in health repair services similar to car repair shops; procedures and prices are standardized, regulated, and inflexibly uniform. Clinics of the future have to become Health Care Centers in order to be more respected and more effective corporate neighbors in offering outreach services in health education and preventive health care. The traditional concept of care for health is much broader than repair management and includes the promotion of lay health competence and responsibility in healthy social and natural environments. The corporate profile and ethics of the clinic as a good and competitive local neighbor will have to focus on [a] better personalized care, [b] education and services in preventive care, [c] direct or web-based information and advice for general, seasonal, or age related health risks, and on developing and improving trustworthy character traits of the clinic as a corporate person and a good neighbor.

  13. Lectures on the nearest neighbor method

    CERN Document Server

    Biau, Gérard

    2015-01-01

    This text presents a wide-ranging and rigorous overview of nearest neighbor methods, one of the most important paradigms in machine learning. Now in one self-contained volume, this book systematically covers key statistical, probabilistic, combinatorial and geometric ideas for understanding, analyzing and developing nearest neighbor methods. Gérard Biau is a professor at Université Pierre et Marie Curie (Paris). Luc Devroye is a professor at the School of Computer Science at McGill University (Montreal).   .

  14. New Sliding Puzzle with Neighbors Swap Motion

    OpenAIRE

    Prihardono, Ariyanto; Kawagoe, Kenichi

    2015-01-01

    The sliding puzzles (15-puzzle, 8-puzzle, 5-puzzle) are known to have 2 kind of puz-zle: solvable puzzle and unsolvable puzzle. In this thesis, we make a new puzzle with only 1 kind of it, solvable puzzle. This new puzzle is made by adopting sliding puzzle with several additional rules from M13 puzzle; the puzzle that is formed form The Mathieu group M13. This puzzle has a movement that called a neighbors swap motion, a rule of movement that enables every neighboring points to swap. This extr...

  15. Recrafting the neighbor-joining method

    Directory of Open Access Journals (Sweden)

    Pedersen Christian NS

    2006-01-01

    Full Text Available Abstract Background The neighbor-joining method by Saitou and Nei is a widely used method for constructing phylogenetic trees. The formulation of the method gives rise to a canonical Θ(n3 algorithm upon which all existing implementations are based. Results In this paper we present techniques for speeding up the canonical neighbor-joining method. Our algorithms construct the same phylogenetic trees as the canonical neighbor-joining method. The best-case running time of our algorithms are O(n2 but the worst-case remains O(n3. We empirically evaluate the performance of our algoritms on distance matrices obtained from the Pfam collection of alignments. The experiments indicate that the running time of our algorithms evolve as Θ(n2 on the examined instance collection. We also compare the running time with that of the QuickTree tool, a widely used efficient implementation of the canonical neighbor-joining method. Conclusion The experiments show that our algorithms also yield a significant speed-up, already for medium sized instances.

  16. Dimensionality reduction with unsupervised nearest neighbors

    CERN Document Server

    Kramer, Oliver

    2013-01-01

    This book is devoted to a novel approach for dimensionality reduction based on the famous nearest neighbor method that is a powerful classification and regression approach. It starts with an introduction to machine learning concepts and a real-world application from the energy domain. Then, unsupervised nearest neighbors (UNN) is introduced as efficient iterative method for dimensionality reduction. Various UNN models are developed step by step, reaching from a simple iterative strategy for discrete latent spaces to a stochastic kernel-based algorithm for learning submanifolds with independent parameterizations. Extensions that allow the embedding of incomplete and noisy patterns are introduced. Various optimization approaches are compared, from evolutionary to swarm-based heuristics. Experimental comparisons to related methodologies taking into account artificial test data sets and also real-world data demonstrate the behavior of UNN in practical scenarios. The book contains numerous color figures to illustr...

  17. Neighbor Rupture Degree of Some Middle Graphs

    Directory of Open Access Journals (Sweden)

    Gökşen BACAK-TURAN

    2017-12-01

    Full Text Available Networks have an important place in our daily lives. Internet networks, electricity networks, water networks, transportation networks, social networks and biological networks are some of the networks we run into every aspects of our lives. A network consists of centers connected by links. A network is represented when centers and connections modelled by vertices and edges, respectively. In consequence of the failure of some centers or connection lines, measurement of the resistance of the network until the communication interrupted is called vulnerability of the network. In this study, neighbor rupture degree which is a parameter that explores the vulnerability values of the resulting graphs due to the failure of some centers of a communication network and its neighboring centers becoming nonfunctional were applied to some middle graphs and neighbor rupture degree of the $M(C_{n},$ $M(P_{n},$ $M(K_{1,n},$ $M(W_{n},$ $M(P_{n}\\times K_{2}$ and $M(C_{n}\\times K_{2}$ have been found.

  18. ACTION RECOGNITION USING SALIENT NEIGHBORING HISTOGRAMS

    DEFF Research Database (Denmark)

    Ren, Huamin; Moeslund, Thomas B.

    2013-01-01

    Combining spatio-temporal interest points with Bag-of-Words models achieves state-of-the-art performance in action recognition. However, existing methods based on “bag-ofwords” models either are too local to capture the variance in space/time or fail to solve the ambiguity problem in spatial...... and temporal dimensions. Instead, we propose a salient vocabulary construction algorithm to select visual words from a global point of view, and form compact descriptors to represent discriminative histograms in the neighborhoods. Those salient neighboring histograms are then trained to model different actions...

  19. A dumbed-down approach to unite Fermilab, its neighbors

    CERN Multimedia

    Constable, B

    2004-01-01

    "...Fermilab is reaching out to its suburban neighbors...With the nation on orange alert, Fermilab scientists no longer can sit on the front porch and invite neighbors in for coffee and quasars" (1 page).

  20. Silicon detectors

    International Nuclear Information System (INIS)

    Klanner, R.

    1984-08-01

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  1. Cryptosporidiosis in Saudi Arabia and neighboring countries

    International Nuclear Information System (INIS)

    Areeshi, Mohammed Y.; Hart, C.A.; Beeching, N.J.

    2007-01-01

    Cryptosporidium is a coccidian protozoan parasite of the intestinal tract that causes severe and sometimes fatal watery diarrhea in immunocompromised patients and self-limiting but prolonged diarrheal disease in immunocompetent individuals. It exists naturally in animals and can be zoonotic. Although cryptosporidiosis is a significant cause of diarrheal disease in both developing and developed countries, it is more prevalent in developing countries and in tropical environments. We examined the epidemiology and disease burden of Cryptosporidium in Saudi Arabia and neighboring countries by reviewing 23 published studies of Cryptosporidium and etiology of diarrhea in between 1986 and 2006. The prevalence of Cryptosporidium infection in human's ranged from 1% to 37% with a median of 4%, while in animals it was for different species of animals and geographic locations of the studies. Most cases of cryptosporidiosis occurred among children less than 7 years of age and particularly in the first two years of life. The seasonality of Cryptosporidium varied depending on the geographic locations of the studies but it generally most prevalent in the rainy season. The most commonly identified species was Cryptosporidium parvum while C.hominis was detected only in one study from Kuwait. The cumulative experience from Saudi Arabia and four neighboring countries (Kuwait, Oman, Jordan and Iraq) suggest that Cryptosporidium is an important cause of diarrhea in human and cattle. However, the findings of this review also demonstrate the limitations of the available data regarding Cryptosporidium species and strains in circulation in these countries. (author)

  2. Model of directed lines for square ice with second-neighbor and third-neighbor interactions

    Science.gov (United States)

    Kirov, Mikhail V.

    2018-02-01

    The investigation of the properties of nanoconfined systems is one of the most rapidly developing scientific fields. Recently it has been established that water monolayer between two graphene sheets forms square ice. Because of the energetic disadvantage, in the structure of the square ice there are no longitudinally arranged molecules. The result is that the structure is formed by unidirectional straight-lines of hydrogen bonds only. A simple but accurate discrete model of square ice with second-neighbor and third-neighbor interactions is proposed. According to this model, the ground state includes all configurations which do not contain three neighboring unidirectional chains of hydrogen bonds. Each triplet increases the energy by the same value. This new model differs from an analogous model with long-range interactions where in the ground state all neighboring chains are antiparallel. The new model is suitable for the corresponding system of point electric (and magnetic) dipoles on the square lattice. It allows separately estimating the different contributions to the total binding energy and helps to understand the properties of infinite monolayers and finite nanostructures. Calculations of the binding energy for square ice and for point dipole system are performed using the packages TINKER and LAMMPS.

  3. The surprising power of neighborly advice.

    Science.gov (United States)

    Gilbert, Daniel T; Killingsworth, Matthew A; Eyre, Rebecca N; Wilson, Timothy D

    2009-03-20

    Two experiments revealed that (i) people can more accurately predict their affective reactions to a future event when they know how a neighbor in their social network reacted to the event than when they know about the event itself and (ii) people do not believe this. Undergraduates made more accurate predictions about their affective reactions to a 5-minute speed date (n = 25) and to a peer evaluation (n = 88) when they knew only how another undergraduate had reacted to these events than when they had information about the events themselves. Both participants and independent judges mistakenly believed that predictions based on information about the event would be more accurate than predictions based on information about how another person had reacted to it.

  4. Observing Literacy Practices in Neighbor Institutions

    DEFF Research Database (Denmark)

    Reusch, Charlotte

    ’procedures on language and literacy. Based on this material, we developed an observation scheme and a guide for preschool teachers to follow, inspired by an action learning concept.During fall 2015, a pilot project is carried out. Preschool teachers from one institution visit a neighbor institution one by one during...... work hours, in order to observe and register how language and literacy events look like there. Afterwards, they share their registrations at a team meeting, and discuss and decide which procedures to test in their own institution. Thus, they form a professional learning network. In the pilot project......The Danish National Centre for Reading and a municipality in southern Denmark cooperate to develop a program to improve preschool children’s early literacy skills. The project aims to support preschool teachers’ ability to create a rich literacy environment for children age 3‒6. Recent research...

  5. Giant Planets: Good Neighbors for Habitable Worlds?

    Science.gov (United States)

    Georgakarakos, Nikolaos; Eggl, Siegfried; Dobbs-Dixon, Ian

    2018-04-01

    The presence of giant planets influences potentially habitable worlds in numerous ways. Massive celestial neighbors can facilitate the formation of planetary cores and modify the influx of asteroids and comets toward Earth analogs later on. Furthermore, giant planets can indirectly change the climate of terrestrial worlds by gravitationally altering their orbits. Investigating 147 well-characterized exoplanetary systems known to date that host a main-sequence star and a giant planet, we show that the presence of “giant neighbors” can reduce a terrestrial planet’s chances to remain habitable, even if both planets have stable orbits. In a small fraction of systems, however, giant planets slightly increase the extent of habitable zones provided that the terrestrial world has a high climate inertia. In providing constraints on where giant planets cease to affect the habitable zone size in a detrimental fashion, we identify prime targets in the search for habitable worlds.

  6. Raman scattering mediated by neighboring molecules

    Science.gov (United States)

    Williams, Mathew D.; Bradshaw, David S.; Andrews, David L.

    2016-05-01

    Raman scattering is most commonly associated with a change in vibrational state within individual molecules, the corresponding frequency shift in the scattered light affording a key way of identifying material structures. In theories where both matter and light are treated quantum mechanically, the fundamental scattering process is represented as the concurrent annihilation of a photon from one radiation mode and creation of another in a different mode. Developing this quantum electrodynamical formulation, the focus of the present work is on the spectroscopic consequences of electrodynamic coupling between neighboring molecules or other kinds of optical center. To encompass these nanoscale interactions, through which the molecular states evolve under the dual influence of the input light and local fields, this work identifies and determines two major mechanisms for each of which different selection rules apply. The constituent optical centers are considered to be chemically different and held in a fixed orientation with respect to each other, either as two components of a larger molecule or a molecular assembly that can undergo free rotation in a fluid medium or as parts of a larger, solid material. The two centers are considered to be separated beyond wavefunction overlap but close enough together to fall within an optical near-field limit, which leads to high inverse power dependences on their local separation. In this investigation, individual centers undergo a Stokes transition, whilst each neighbor of a different species remains in its original electronic and vibrational state. Analogous principles are applicable for the anti-Stokes case. The analysis concludes by considering the experimental consequences of applying this spectroscopic interpretation to fluid media; explicitly, the selection rules and the impact of pressure on the radiant intensity of this process.

  7. Raman scattering mediated by neighboring molecules

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Mathew D.; Bradshaw, David S.; Andrews, David L., E-mail: david.andrews@physics.org [School of Chemistry, University of East Anglia, Norwich NR4 7TJ (United Kingdom)

    2016-05-07

    Raman scattering is most commonly associated with a change in vibrational state within individual molecules, the corresponding frequency shift in the scattered light affording a key way of identifying material structures. In theories where both matter and light are treated quantum mechanically, the fundamental scattering process is represented as the concurrent annihilation of a photon from one radiation mode and creation of another in a different mode. Developing this quantum electrodynamical formulation, the focus of the present work is on the spectroscopic consequences of electrodynamic coupling between neighboring molecules or other kinds of optical center. To encompass these nanoscale interactions, through which the molecular states evolve under the dual influence of the input light and local fields, this work identifies and determines two major mechanisms for each of which different selection rules apply. The constituent optical centers are considered to be chemically different and held in a fixed orientation with respect to each other, either as two components of a larger molecule or a molecular assembly that can undergo free rotation in a fluid medium or as parts of a larger, solid material. The two centers are considered to be separated beyond wavefunction overlap but close enough together to fall within an optical near-field limit, which leads to high inverse power dependences on their local separation. In this investigation, individual centers undergo a Stokes transition, whilst each neighbor of a different species remains in its original electronic and vibrational state. Analogous principles are applicable for the anti-Stokes case. The analysis concludes by considering the experimental consequences of applying this spectroscopic interpretation to fluid media; explicitly, the selection rules and the impact of pressure on the radiant intensity of this process.

  8. Text Categorization Using Weight Adjusted k-Nearest Neighbor Classification

    National Research Council Canada - National Science Library

    Han, Euihong; Karypis, George; Kumar, Vipin

    1999-01-01

    .... The authors present a nearest neighbor classification scheme for text categorization in which the importance of discriminating words is learned using mutual information and weight adjustment techniques...

  9. Common Nearest Neighbor Clustering—A Benchmark

    Directory of Open Access Journals (Sweden)

    Oliver Lemke

    2018-02-01

    Full Text Available Cluster analyses are often conducted with the goal to characterize an underlying probability density, for which the data-point density serves as an estimate for this probability density. We here test and benchmark the common nearest neighbor (CNN cluster algorithm. This algorithm assigns a spherical neighborhood R to each data point and estimates the data-point density between two data points as the number of data points N in the overlapping region of their neighborhoods (step 1. The main principle in the CNN cluster algorithm is cluster growing. This grows the clusters by sequentially adding data points and thereby effectively positions the border of the clusters along an iso-surface of the underlying probability density. This yields a strict partitioning with outliers, for which the cluster represents peaks in the underlying probability density—termed core sets (step 2. The removal of the outliers on the basis of a threshold criterion is optional (step 3. The benchmark datasets address a series of typical challenges, including datasets with a very high dimensional state space and datasets in which the cluster centroids are aligned along an underlying structure (Birch sets. The performance of the CNN algorithm is evaluated with respect to these challenges. The results indicate that the CNN cluster algorithm can be useful in a wide range of settings. Cluster algorithms are particularly important for the analysis of molecular dynamics (MD simulations. We demonstrate how the CNN cluster results can be used as a discretization of the molecular state space for the construction of a core-set model of the MD improving the accuracy compared to conventional full-partitioning models. The software for the CNN clustering is available on GitHub.

  10. ALIGNMENTS OF GROUP GALAXIES WITH NEIGHBORING GROUPS

    International Nuclear Information System (INIS)

    Wang Yougang; Chen Xuelei; Park, Changbom; Yang Xiaohu; Choi, Yun-Young

    2009-01-01

    Using a sample of galaxy groups found in the Sloan Digital Sky Survey Data Release 4, we measure the following four types of alignment signals: (1) the alignment between the distributions of the satellites of each group relative to the direction of the nearest neighbor group (NNG); (2) the alignment between the major axis direction of the central galaxy of the host group (HG) and the direction of the NNG; (3) the alignment between the major axes of the central galaxies of the HG and the NNG; and (4) the alignment between the major axes of the satellites of the HG and the direction of the NNG. We find strong signal of alignment between the satellite distribution and the orientation of central galaxy relative to the direction of the NNG, even when the NNG is located beyond 3r vir of the host group. The major axis of the central galaxy of the HG is aligned with the direction of the NNG. The alignment signals are more prominent for groups that are more massive and with early-type central galaxies. We also find that there is a preference for the two major axes of the central galaxies of the HG and NNG to be parallel for the system with both early central galaxies, however, not for the systems with both late-type central galaxies. For the orientation of satellite galaxies, we do not find any significant alignment signals relative to the direction of the NNG. From these four types of alignment measurements, we conclude that the large-scale environment traced by the nearby group affects primarily the shape of the host dark matter halo, and hence also affects the distribution of satellite galaxies and the orientation of central galaxies. In addition, the NNG directly affects the distribution of the satellite galaxies by inducing asymmetric alignment signals, and the NNG at very small separation may also contribute a second-order impact on the orientation of the central galaxy in the HG.

  11. Frog sound identification using extended k-nearest neighbor classifier

    Science.gov (United States)

    Mukahar, Nordiana; Affendi Rosdi, Bakhtiar; Athiar Ramli, Dzati; Jaafar, Haryati

    2017-09-01

    Frog sound identification based on the vocalization becomes important for biological research and environmental monitoring. As a result, different types of feature extractions and classifiers have been employed to evaluate the accuracy of frog sound identification. This paper presents a frog sound identification with Extended k-Nearest Neighbor (EKNN) classifier. The EKNN classifier integrates the nearest neighbors and mutual sharing of neighborhood concepts, with the aims of improving the classification performance. It makes a prediction based on who are the nearest neighbors of the testing sample and who consider the testing sample as their nearest neighbors. In order to evaluate the classification performance in frog sound identification, the EKNN classifier is compared with competing classifier, k -Nearest Neighbor (KNN), Fuzzy k -Nearest Neighbor (FKNN) k - General Nearest Neighbor (KGNN)and Mutual k -Nearest Neighbor (MKNN) on the recorded sounds of 15 frog species obtained in Malaysia forest. The recorded sounds have been segmented using Short Time Energy and Short Time Average Zero Crossing Rate (STE+STAZCR), sinusoidal modeling (SM), manual and the combination of Energy (E) and Zero Crossing Rate (ZCR) (E+ZCR) while the features are extracted by Mel Frequency Cepstrum Coefficient (MFCC). The experimental results have shown that the EKNCN classifier exhibits the best performance in terms of accuracy compared to the competing classifiers, KNN, FKNN, GKNN and MKNN for all cases.

  12. The Islands Approach to Nearest Neighbor Querying in Spatial Networks

    DEFF Research Database (Denmark)

    Huang, Xuegang; Jensen, Christian Søndergaard; Saltenis, Simonas

    2005-01-01

    , and versatile approach to k nearest neighbor computation that obviates the need for using several k nearest neighbor approaches for supporting a single service scenario. The experimental comparison with the existing techniques uses real-world road network data and considers both I/O and CPU performance...

  13. Performance modeling of neighbor discovery in proactive routing protocols

    Directory of Open Access Journals (Sweden)

    Andres Medina

    2011-07-01

    Full Text Available It is well known that neighbor discovery is a critical component of proactive routing protocols in wireless ad hoc networks. However there is no formal study on the performance of proposed neighbor discovery mechanisms. This paper provides a detailed model of key performance metrics of neighbor discovery algorithms, such as node degree and the distribution of the distance to symmetric neighbors. The model accounts for the dynamics of neighbor discovery as well as node density, mobility, radio and interference. The paper demonstrates a method for applying these models to the evaluation of global network metrics. In particular, it describes a model of network connectivity. Validation of the models shows that the degree estimate agrees, within 5% error, with simulations for the considered scenarios. The work presented in this paper serves as a basis for the performance evaluation of remaining performance metrics of routing protocols, vital for large scale deployment of ad hoc networks.

  14. Chalcogen donnors in silicon

    International Nuclear Information System (INIS)

    Scolfaro, L.M.R.

    1985-01-01

    The electronic stucture of chalcogen impurities in silicon which give rise to deep levels in the forbidden band gap of that semiconductor is studied. The molecular cluster model within the formalism of the multiple scattering method in the Xα local density approximation was used . The surface orbitals were treated by using the Watson sphere model. Studies were carried out for the isolated substitutional sulfur and selenium impurities (Si:S and Si:Se). A pioneer investigation was performed for the nearest-neighbor impurity pairs of sulfur and selenium (Si:S 2 and Si:Se 2 ). All the systems were also analysed in the positive charge states (Si:S + , Si:Se + and Si:Se 2 + ) and for the isolated impurities the calculations were carried out to the spin polarized limit. The obtained results were used to interpret recent photoconductivity, photocapitance, EPR and DLTS data on these centers. It was observed that the adopted model is able to provide a satisfactory description of the electronic structure of the chalcogen impurity centers in silicon. (autor) [pt

  15. SVX/silicon detector studies

    International Nuclear Information System (INIS)

    Bagby, L.; Johnson, M.; Lipton, R.; Gu, W.

    1995-11-01

    AC coupled silicon detectors, being used for the DO upgrade, may have substantial voltage across the coupling capacitor. Failed capacitors can present ∼50 V to the input of the SVX, Silicon Vertex, device. We measured the effects that failed detector coupling capacitors have on the SVXD (rad soft 3μm), SVXH (rad hard 1.2μm), and SVXIIb (rad soft 1.2μm) amplifier / readout devices. The test results show that neighboring channels saturate when an excessive voltage is applied directly to a SVX channel. We believe that the effects are due to current diffusion within the SVX substrate rather than surface currents on the detectors. This paper discusses the magnitude of the saturation and a possible solution to the problem

  16. Our Galactic Neighbor Hosts Complex Organic Molecules

    Science.gov (United States)

    Hensley, Kerry

    2018-03-01

    For the first time, data from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal the presence of methyl formate and dimethyl ether in a star-forming region outside our galaxy. This discovery has important implications for the formation and survival of complex organic compounds importantfor the formation of life in low-metallicity galaxies bothyoung and old.No Simple Picture of Complex Molecule FormationALMA, pictured here with the Magellanic Clouds above, has observed organic molecules in our Milky Way Galaxy and beyond. [ESO/C. Malin]Complex organic molecules (those with at least six atoms, one or more of which must be carbon) are the precursors to the building blocks of life. Knowing how and where complex organic molecules can form is a key part of understanding how life came to be on Earth and how it might arise elsewhere in the universe. From exoplanet atmospheres to interstellar space, complex organic molecules are ubiquitous in the Milky Way.In our galaxy, complex organic molecules are often found in the intense environments of hot cores clumps of dense molecular gas surrounding the sites of star formation. However, its not yet fully understood how the complex organic molecules found in hot cores come to be. One possibility is that the compounds condense onto cold dust grains long before the young stars begin heating their natal shrouds. Alternatively, they might assemble themselves from the hot, dense gas surrounding the blazing protostars.Composite infrared and optical image of the N 113 star-forming region in the LMC. The ALMA coverage is indicated by the gray line. Click to enlarge. [Sewio et al. 2018]Detecting Complexity, a Galaxy AwayUsing ALMA, a team of researchers led by Marta Sewio (NASA Goddard Space Flight Center) recently detected two complex organic molecules methyl formate and dimethyl ether for the first time in our neighboring galaxy, the Large Magellanic Cloud (LMC). Previous searches for organic molecules in the LMC detected

  17. Dimensional testing for reverse k-nearest neighbor search

    DEFF Research Database (Denmark)

    Casanova, Guillaume; Englmeier, Elias; Houle, Michael E.

    2017-01-01

    Given a query object q, reverse k-nearest neighbor (RkNN) search aims to locate those objects of the database that have q among their k-nearest neighbors. In this paper, we propose an approximation method for solving RkNN queries, where the pruning operations and termination tests are guided...... by a characterization of the intrinsic dimensionality of the data. The method can accommodate any index structure supporting incremental (forward) nearest-neighbor search for the generation and verification of candidates, while avoiding impractically-high preprocessing costs. We also provide experimental evidence...

  18. Color and neighbor edge directional difference feature for image retrieval

    Institute of Scientific and Technical Information of China (English)

    Chaobing Huang; Shengsheng Yu; Jingli Zhou; Hongwei Lu

    2005-01-01

    @@ A novel image feature termed neighbor edge directional difference unit histogram is proposed, in which the neighbor edge directional difference unit is defined and computed for every pixel in the image, and is used to generate the neighbor edge directional difference unit histogram. This histogram and color histogram are used as feature indexes to retrieve color image. The feature is invariant to image scaling and translation and has more powerful descriptive for the natural color images. Experimental results show that the feature can achieve better retrieval performance than other color-spatial features.

  19. Scalable Nearest Neighbor Algorithms for High Dimensional Data.

    Science.gov (United States)

    Muja, Marius; Lowe, David G

    2014-11-01

    For many computer vision and machine learning problems, large training sets are key for good performance. However, the most computationally expensive part of many computer vision and machine learning algorithms consists of finding nearest neighbor matches to high dimensional vectors that represent the training data. We propose new algorithms for approximate nearest neighbor matching and evaluate and compare them with previous algorithms. For matching high dimensional features, we find two algorithms to be the most efficient: the randomized k-d forest and a new algorithm proposed in this paper, the priority search k-means tree. We also propose a new algorithm for matching binary features by searching multiple hierarchical clustering trees and show it outperforms methods typically used in the literature. We show that the optimal nearest neighbor algorithm and its parameters depend on the data set characteristics and describe an automated configuration procedure for finding the best algorithm to search a particular data set. In order to scale to very large data sets that would otherwise not fit in the memory of a single machine, we propose a distributed nearest neighbor matching framework that can be used with any of the algorithms described in the paper. All this research has been released as an open source library called fast library for approximate nearest neighbors (FLANN), which has been incorporated into OpenCV and is now one of the most popular libraries for nearest neighbor matching.

  20. The role of orthography in the semantic activation of neighbors.

    Science.gov (United States)

    Hino, Yasushi; Lupker, Stephen J; Taylor, Tamsen E

    2012-09-01

    There is now considerable evidence that a letter string can activate semantic information appropriate to its orthographic neighbors (e.g., Forster & Hector's, 2002, TURPLE effect). This phenomenon is the focus of the present research. Using Japanese words, we examined whether semantic activation of neighbors is driven directly by orthographic similarity alone or whether there is also a role for phonological similarity. In Experiment 1, using a relatedness judgment task in which a Kanji word-Katakana word pair was presented on each trial, an inhibitory effect was observed when the initial Kanji word was related to an orthographic and phonological neighbor of the Katakana word target but not when the initial Kanji word was related to a phonological but not orthographic neighbor of the Katakana word target. This result suggests that phonology plays little, if any, role in the activation of neighbors' semantics when reading familiar words. In Experiment 2, the targets were transcribed into Hiragana, a script they are typically not written in, requiring readers to engage in phonological coding. In that experiment, inhibitory effects were observed in both conditions. This result indicates that phonologically mediated semantic activation of neighbors will emerge when phonological processing is necessary in order to understand a written word (e.g., when that word is transcribed into an unfamiliar script). PsycINFO Database Record (c) 2012 APA, all rights reserved.

  1. Silicon Qubits

    Energy Technology Data Exchange (ETDEWEB)

    Ladd, Thaddeus D. [HRL Laboratories, LLC, Malibu, CA (United States); Carroll, Malcolm S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-28

    Silicon is a promising material candidate for qubits due to the combination of worldwide infrastructure in silicon microelectronics fabrication and the capability to drastically reduce decohering noise channels via chemical purification and isotopic enhancement. However, a variety of challenges in fabrication, control, and measurement leaves unclear the best strategy for fully realizing this material’s future potential. In this article, we survey three basic qubit types: those based on substitutional donors, on metal-oxide-semiconductor (MOS) structures, and on Si/SiGe heterostructures. We also discuss the multiple schema used to define and control Si qubits, which may exploit the manipulation and detection of a single electron charge, the state of a single electron spin, or the collective states of multiple spins. Far from being comprehensive, this article provides a brief orientation to the rapidly evolving field of silicon qubit technology and is intended as an approachable entry point for a researcher new to this field.

  2. Haldane to Dimer Phase Transition in the Spin-1 Haldane System with Bond-Alternating Nearest-Neighbor and Uniform Next-Nearest-Neighbor Exchange Interactions

    OpenAIRE

    Takashi, Tonegawa; Makoto, Kaburagi; Takeshi, Nakao; Department of Physics, Faculty of Science, Kobe University; Faculty of Cross-Cultural Studies, Kobe University; Department of Physics, Faculty of Science, Kobe University

    1995-01-01

    The Haldane to dimer phase transition is studied in the spin-1 Haldane system with bond-alternating nearest-neighbor and uniform next-nearest-neighbor exchange interactions, where both interactions are antiferromagnetic and thus compete with each other. By using a method of exact diagonalization, the ground-state phase diagram on the ratio of the next-nearest-neighbor interaction constant to the nearest-neighbor one versus the bond-alternation parameter of the nearest-neighbor interactions is...

  3. Beyond formal groups: neighboring acts and watershed protection in Appalachia

    Directory of Open Access Journals (Sweden)

    Heather Lukacs

    2016-09-01

    Full Text Available This paper explores how watershed organizations in Appalachia have persisted in addressing water quality issues in areas with a history of coal mining. We identified two watershed groups that have taken responsibility for restoring local creeks that were previously highly degraded and sporadically managed. These watershed groups represent cases of self-organized commons governance in resource-rich, economically poor Appalachian communities. We describe the extent and characteristics of links between watershed group volunteers and watershed residents who are not group members. Through surveys, participant observation, and key-informant consultation, we found that neighbors – group members as well as non-group-members – supported the group's function through informal neighboring acts. Past research has shown that local commons governance institutions benefit from being nested in supportive external structures. We found that the persistence and success of community watershed organizations depends on the informal participation of local residents, affirming the necessity of looking beyond formal, organized groups to understand the resources, expertise, and information needed to address complex water pollution at the watershed level. Our findings augment the concept of nestedness in commons governance to include that of a formal organization acting as a neighbor that exchanges informal neighboring acts with local residents. In this way, we extend the concept of neighboring to include interactions between individuals and a group operating in the same geographic area.

  4. Multiple k Nearest Neighbor Query Processing in Spatial Network Databases

    DEFF Research Database (Denmark)

    Xuegang, Huang; Jensen, Christian Søndergaard; Saltenis, Simonas

    2006-01-01

    This paper concerns the efficient processing of multiple k nearest neighbor queries in a road-network setting. The assumed setting covers a range of scenarios such as the one where a large population of mobile service users that are constrained to a road network issue nearest-neighbor queries...... for points of interest that are accessible via the road network. Given multiple k nearest neighbor queries, the paper proposes progressive techniques that selectively cache query results in main memory and subsequently reuse these for query processing. The paper initially proposes techniques for the case...... where an upper bound on k is known a priori and then extends the techniques to the case where this is not so. Based on empirical studies with real-world data, the paper offers insight into the circumstances under which the different proposed techniques can be used with advantage for multiple k nearest...

  5. Nearest unlike neighbor (NUN): an aid to decision confidence estimation

    Science.gov (United States)

    Dasarathy, Belur V.

    1995-09-01

    The concept of nearest unlike neighbor (NUN), proposed and explored previously in the design of nearest neighbor (NN) based decision systems, is further exploited in this study to develop a measure of confidence in the decisions made by NN-based decision systems. This measure of confidence, on the basis of comparison with a user-defined threshold, may be used to determine the acceptability of the decision provided by the NN-based decision system. The concepts, associated methodology, and some illustrative numerical examples using the now classical Iris data to bring out the ease of implementation and effectiveness of the proposed innovations are presented.

  6. Combination of silicon nitride and porous silicon induced optoelectronic features enhancement of multicrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rabha, Mohamed Ben; Dimassi, Wissem; Gaidi, Mounir; Ezzaouia, Hatem; Bessais, Brahim [Laboratoire de Photovoltaique, Centre de Recherches et des Technologies de l' Energie, Technopole de Borj-Cedria, BP 95, 2050 Hammam-Lif (Tunisia)

    2011-06-15

    The effects of antireflection (ARC) and surface passivation films on optoelectronic features of multicrystalline silicon (mc-Si) were investigated in order to perform high efficiency solar cells. A double layer consisting of Plasma Enhanced Chemical Vapor Deposition (PECVD) of silicon nitride (SiN{sub x}) on porous silicon (PS) was achieved on mc-Si surfaces. It was found that this treatment decreases the total surface reflectivity from about 25% to around 6% in the 450-1100 nm wavelength range. As a result, the effective minority carrier diffusion length, estimated from the Laser-beam-induced current (LBIC) method, was found to increase from 312 {mu}m for PS-treated cells to about 798 {mu}m for SiN{sub x}/PS-treated ones. The deposition of SiN{sub x} was found to impressively enhance the minority carrier diffusion length probably due to hydrogen passivation of surface, grain boundaries and bulk defects. Fourier Transform Infrared Spectroscopy (FTIR) shows that the vibration modes of the highly suitable passivating Si-H bonds exhibit frequency shifts toward higher wavenumber, depending on the x ratio of the introduced N atoms neighbors. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Contrasting demographic histories of the neighboring bonobo and chimpanzee

    DEFF Research Database (Denmark)

    Hvilsom, Christina; Carlsen, Frands; Heller, Rasmus

    2014-01-01

    of the neighboring bonobo remained constant. The changes in population size are likely linked to changes in habitat area due to climate oscillations during the late Pleistocene. Furthermore, the timing of population expansion for the rainforest-adapted chimpanzee is concurrent with the expansion of the savanna...

  8. Local randomization in neighbor selection improves PRM roadmap quality

    KAUST Repository

    McMahon, Troy

    2012-10-01

    Probabilistic Roadmap Methods (PRMs) are one of the most used classes of motion planning methods. These sampling-based methods generate robot configurations (nodes) and then connect them to form a graph (roadmap) containing representative feasible pathways. A key step in PRM roadmap construction involves identifying a set of candidate neighbors for each node. Traditionally, these candidates are chosen to be the k-closest nodes based on a given distance metric. In this paper, we propose a new neighbor selection policy called LocalRand(k,K\\'), that first computes the K\\' closest nodes to a specified node and then selects k of those nodes at random. Intuitively, LocalRand attempts to benefit from random sampling while maintaining the higher levels of local planner success inherent to selecting more local neighbors. We provide a methodology for selecting the parameters k and K\\'. We perform an experimental comparison which shows that for both rigid and articulated robots, LocalRand results in roadmaps that are better connected than the traditional k-closest policy or a purely random neighbor selection policy. The cost required to achieve these results is shown to be comparable to k-closest. © 2012 IEEE.

  9. Local randomization in neighbor selection improves PRM roadmap quality

    KAUST Repository

    McMahon, Troy; Jacobs, Sam; Boyd, Bryan; Tapia, Lydia; Amato, Nancy M.

    2012-01-01

    Probabilistic Roadmap Methods (PRMs) are one of the most used classes of motion planning methods. These sampling-based methods generate robot configurations (nodes) and then connect them to form a graph (roadmap) containing representative feasible pathways. A key step in PRM roadmap construction involves identifying a set of candidate neighbors for each node. Traditionally, these candidates are chosen to be the k-closest nodes based on a given distance metric. In this paper, we propose a new neighbor selection policy called LocalRand(k,K'), that first computes the K' closest nodes to a specified node and then selects k of those nodes at random. Intuitively, LocalRand attempts to benefit from random sampling while maintaining the higher levels of local planner success inherent to selecting more local neighbors. We provide a methodology for selecting the parameters k and K'. We perform an experimental comparison which shows that for both rigid and articulated robots, LocalRand results in roadmaps that are better connected than the traditional k-closest policy or a purely random neighbor selection policy. The cost required to achieve these results is shown to be comparable to k-closest. © 2012 IEEE.

  10. Clustered K nearest neighbor algorithm for daily inflow forecasting

    NARCIS (Netherlands)

    Akbari, M.; Van Overloop, P.J.A.T.M.; Afshar, A.

    2010-01-01

    Instance based learning (IBL) algorithms are a common choice among data driven algorithms for inflow forecasting. They are based on the similarity principle and prediction is made by the finite number of similar neighbors. In this sense, the similarity of a query instance is estimated according to

  11. Near Neighbor Distribution in Sets of Fractal Nature

    Czech Academy of Sciences Publication Activity Database

    Jiřina, Marcel

    2013-01-01

    Roč. 5, č. 1 (2013), s. 159-166 ISSN 2150-7988 R&D Projects: GA MŠk(CZ) LG12020 Institutional support: RVO:67985807 Keywords : nearest neighbor * fractal set * multifractal * Erlang distribution Subject RIV: BB - Applied Statistics, Operational Research http://www.mirlabs.org/ijcisim/regular_papers_2013/Paper91.pdf

  12. Neighboring Genes Show Correlated Evolution in Gene Expression

    Science.gov (United States)

    Ghanbarian, Avazeh T.; Hurst, Laurence D.

    2015-01-01

    When considering the evolution of a gene’s expression profile, we commonly assume that this is unaffected by its genomic neighborhood. This is, however, in contrast to what we know about the lack of autonomy between neighboring genes in gene expression profiles in extant taxa. Indeed, in all eukaryotic genomes genes of similar expression-profile tend to cluster, reflecting chromatin level dynamics. Does it follow that if a gene increases expression in a particular lineage then the genomic neighbors will also increase in their expression or is gene expression evolution autonomous? To address this here we consider evolution of human gene expression since the human-chimp common ancestor, allowing for both variation in estimation of current expression level and error in Bayesian estimation of the ancestral state. We find that in all tissues and both sexes, the change in gene expression of a focal gene on average predicts the change in gene expression of neighbors. The effect is highly pronounced in the immediate vicinity (genes increasing their expression in humans tend to avoid nuclear lamina domains and be enriched for the gene activator 5-hydroxymethylcytosine, we conclude that, most probably owing to chromatin level control of gene expression, a change in gene expression of one gene likely affects the expression evolution of neighbors, what we term expression piggybacking, an analog of hitchhiking. PMID:25743543

  13. Secure Nearest Neighbor Query on Crowd-Sensing Data

    Directory of Open Access Journals (Sweden)

    Ke Cheng

    2016-09-01

    Full Text Available Nearest neighbor queries are fundamental in location-based services, and secure nearest neighbor queries mainly focus on how to securely and quickly retrieve the nearest neighbor in the outsourced cloud server. However, the previous big data system structure has changed because of the crowd-sensing data. On the one hand, sensing data terminals as the data owner are numerous and mistrustful, while, on the other hand, in most cases, the terminals find it difficult to finish many safety operation due to computation and storage capability constraints. In light of they Multi Owners and Multi Users (MOMU situation in the crowd-sensing data cloud environment, this paper presents a secure nearest neighbor query scheme based on the proxy server architecture, which is constructed by protocols of secure two-party computation and secure Voronoi diagram algorithm. It not only preserves the data confidentiality and query privacy but also effectively resists the collusion between the cloud server and the data owners or users. Finally, extensive theoretical and experimental evaluations are presented to show that our proposed scheme achieves a superior balance between the security and query performance compared to other schemes.

  14. Thermodynamic systematics of oxides of americium, curium, and neighboring elements

    International Nuclear Information System (INIS)

    Morss, L.R.

    1984-01-01

    Recently-obtained calorimetric data on the sesquioxides and dioxides of americium and curium are summarized. These data are combined with other properties of the actinide elements to elucidate the stability relationships among these oxides and to predict the behavior of neighboring actinide oxides. 45 references, 4 figures, 5 tables

  15. Incidence and Prevalence of Tuberculosis in Iran and Neighboring Countries

    Directory of Open Access Journals (Sweden)

    Arezoo Tavakoli

    2017-07-01

    Full Text Available Background Tuberculosis is one of the major public health concerns in many countries, however the available and effective treatment is known. Tuberculosis typically determined with socio-economic problems such as war, malnutrition and HIV prevalence. In Iran, many progresses are carried to control tuberculosis but, different factors such as immigration from neighboring countries are affective to tuberculosis infection. Objectives In this paper, the incidence and prevalence of tuberculosis is evaluated in different regions of Iran and neighboring countries. Methods The data are collected from different and valid sources such as Scopus, Pubmed and also many reports from world health organization (WHO and center of disease control and prevention (CDC for a period of 25 years (1990 - 2015 evaluated for Iran and neighboring countries. Results This study as a descriptive- analytical research is conducted cross- sectional among Iran and neighboring countries since 1990. The information is obtained from exact and valid informative data from web of sciences. The east and west border countries of Iran which are faced with war and immigration in Afghanistan, Pakistan and Iraq are source of tuberculosis infection that effect on tuberculosis prevalence in Iran. The data were analyzed by SPSS 22 and Excel 2013. Conclusions The incidence of tuberculosis in Iran has been decreased because of many controlling actions such as BCG vaccination, electronic reporting system for tuberculosis and free access to tuberculosis medication. Some of Iran neighboring countries such as Tajikistan and Pakistan have the highest incidence of tuberculosis which known as a challenge for tuberculosis control in Iran while Saudi Arabia and Turkey have the lowest incidence.

  16. Local biotic adaptation of trees and shrubs to plant neighbors

    Science.gov (United States)

    Grady, Kevin C.; Wood, Troy E.; Kolb, Thomas E.; Hersch-Green, Erika; Shuster, Stephen M.; Gehring, Catherine A.; Hart, Stephen C.; Allan, Gerard J.; Whitham, Thomas G.

    2017-01-01

    Natural selection as a result of plant–plant interactions can lead to local biotic adaptation. This may occur where species frequently interact and compete intensely for resources limiting growth, survival, and reproduction. Selection is demonstrated by comparing a genotype interacting with con- or hetero-specific sympatric neighbor genotypes with a shared site-level history (derived from the same source location), to the same genotype interacting with foreign neighbor genotypes (from different sources). Better genotype performance in sympatric than allopatric neighborhoods provides evidence of local biotic adaptation. This pattern might be explained by selection to avoid competition by shifting resource niches (differentiation) or by interactions benefitting one or more members (facilitation). We tested for local biotic adaptation among two riparian trees, Populus fremontii and Salix gooddingii, and the shrub Salix exigua by transplanting replicated genotypes from multiple source locations to a 17 000 tree common garden with sympatric and allopatric treatments along the Colorado River in California. Three major patterns were observed: 1) across species, 62 of 88 genotypes grew faster with sympatric neighbors than allopatric neighbors; 2) these growth rates, on an individual tree basis, were 44, 15 and 33% higher in sympatric than allopatric treatments for P. fremontii, S. exigua and S. gooddingii, respectively, and; 3) survivorship was higher in sympatric treatments for P. fremontiiand S. exigua. These results support the view that fitness of foundation species supporting diverse communities and dominating ecosystem processes is determined by adaptive interactions among multiple plant species with the outcome that performance depends on the genetic identity of plant neighbors. The occurrence of evolution in a plant-community context for trees and shrubs builds on ecological evolutionary research that has demonstrated co-evolution among herbaceous taxa, and

  17. Geochemistry of silicon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Tiping; Li, Yanhe; Gao, Jianfei; Hu, Bin [Chinese Academy of Geological Science, Beijing (China). Inst. of Mineral Resources; Jiang, Shaoyong [China Univ. of Geosciences, Wuhan (China).

    2018-04-01

    Silicon is one of the most abundant elements in the Earth and silicon isotope geochemistry is important in identifying the silicon source for various geological bodies and in studying the behavior of silicon in different geological processes. This book starts with an introduction on the development of silicon isotope geochemistry. Various analytical methods are described and compared with each other in detail. The mechanisms of silicon isotope fractionation are discussed, and silicon isotope distributions in various extraterrestrial and terrestrial reservoirs are updated. Besides, the applications of silicon isotopes in several important fields are presented.

  18. Modeling crosstalk in silicon photomultipliers

    International Nuclear Information System (INIS)

    Gallego, L; Rosado, J; Blanco, F; Arqueros, F

    2013-01-01

    Optical crosstalk seriously limits the photon-counting resolution of silicon photomultipliers. In this work, realistic analytical models to describe the crosstalk effects on the response of these photodetectors are presented and compared with experimental data. The proposed models are based on the hypothesis that each pixel of the array has a finite number of available neighboring pixels to excite via crosstalk. Dead-time effects and geometrical aspects of the propagation of crosstalk between neighbors are taken into account in the models for different neighborhood configurations. Simple expressions to account for crosstalk effects on the pulse-height spectrum as well as to evaluate the excess noise factor due to crosstalk are also given. Dedicated measurements were carried out under both dark-count conditions and pulsed illumination. Moreover, the influence of afterpulsing on the measured pulse-height spectrum was studied, and a measurement of the recovery time of pixels was reported. High-resolution pulse-height spectra were obtained by means of a detailed waveform analysis, and the results have been used to validate our crosstalk models.

  19. Social dilemma alleviated by sharing the gains with immediate neighbors

    Science.gov (United States)

    Wu, Zhi-Xi; Yang, Han-Xin

    2014-01-01

    We study the evolution of cooperation in the evolutionary spatial prisoner's dilemma game (PDG) and snowdrift game (SG), within which a fraction α of the payoffs of each player gained from direct game interactions is shared equally by the immediate neighbors. The magnitude of the parameter α therefore characterizes the degree of the relatedness among the neighboring players. By means of extensive Monte Carlo simulations as well as an extended mean-field approximation method, we trace the frequency of cooperation in the stationary state. We find that plugging into relatedness can significantly promote the evolution of cooperation in the context of both studied games. Unexpectedly, cooperation can be more readily established in the spatial PDG than that in the spatial SG, given that the degree of relatedness and the cost-to-benefit ratio of mutual cooperation are properly formulated. The relevance of our model with the stakeholder theory is also briefly discussed.

  20. Grain price spikes and beggar-thy-neighbor policy responses

    DEFF Research Database (Denmark)

    Boysen, Ole; Jensen, Hans Grinsted

    on the agenda of various international policy fora, including the annual meetings of G20 countries in recent years. For that reason, recent studies have attempted to quantify the extent to which such policy actions contributed to the rise in food prices. A study by Jensen & Anderson (2014) uses the global AGE...... model GTAP and the corresponding database to quantify the global policy actions contributions to the raise in food prices by modeling the changes in distortions to agricultural incentives in the period 2006 to 2008. We link the results from this global model into a national AGE model, highlighting how...... global "Beggar-thy-Neighbor Policy Responses" impacted on poor households in Uganda. More specifically we examine the following research questions: What were the Ugandan economy-wide and poverty impacts of the price spikes? What was the impact of other countries "Beggar-thy-Neighbor Policy Responses...

  1. Nearest Neighbor Networks: clustering expression data based on gene neighborhoods

    Directory of Open Access Journals (Sweden)

    Olszewski Kellen L

    2007-07-01

    Full Text Available Abstract Background The availability of microarrays measuring thousands of genes simultaneously across hundreds of biological conditions represents an opportunity to understand both individual biological pathways and the integrated workings of the cell. However, translating this amount of data into biological insight remains a daunting task. An important initial step in the analysis of microarray data is clustering of genes with similar behavior. A number of classical techniques are commonly used to perform this task, particularly hierarchical and K-means clustering, and many novel approaches have been suggested recently. While these approaches are useful, they are not without drawbacks; these methods can find clusters in purely random data, and even clusters enriched for biological functions can be skewed towards a small number of processes (e.g. ribosomes. Results We developed Nearest Neighbor Networks (NNN, a graph-based algorithm to generate clusters of genes with similar expression profiles. This method produces clusters based on overlapping cliques within an interaction network generated from mutual nearest neighborhoods. This focus on nearest neighbors rather than on absolute distance measures allows us to capture clusters with high connectivity even when they are spatially separated, and requiring mutual nearest neighbors allows genes with no sufficiently similar partners to remain unclustered. We compared the clusters generated by NNN with those generated by eight other clustering methods. NNN was particularly successful at generating functionally coherent clusters with high precision, and these clusters generally represented a much broader selection of biological processes than those recovered by other methods. Conclusion The Nearest Neighbor Networks algorithm is a valuable clustering method that effectively groups genes that are likely to be functionally related. It is particularly attractive due to its simplicity, its success in the

  2. Crimean-Congo hemorrhagic fever in Iran and neighboring countries

    DEFF Research Database (Denmark)

    Chinikar, S; Ghiasi, Seyed Mojtaba; Hewson, R

    2010-01-01

    Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic viral disease that is asymptomatic in infected livestock, but a serious threat to humans. Human infections begin with nonspecific febrile symptoms, but progress to a serious hemorrhagic syndrome with a case fatality rate of 2-50%. Although the ...... in Iran and neighboring countries and provide evidence of over 5000 confirmed cases of CCHF in a single period/season....

  3. Fast Most Similar Neighbor (MSN) classifiers for Mixed Data

    OpenAIRE

    Hernández Rodríguez, Selene

    2010-01-01

    The k nearest neighbor (k-NN) classifier has been extensively used in Pattern Recognition because of its simplicity and its good performance. However, in large datasets applications, the exhaustive k-NN classifier becomes impractical. Therefore, many fast k-NN classifiers have been developed; most of them rely on metric properties (usually the triangle inequality) to reduce the number of prototype comparisons. Hence, the existing fast k-NN classifiers are applicable only when the comparison f...

  4. ENTROPY CHARACTERISTICS IN MODELS FOR COORDINATION OF NEIGHBORING ROAD SECTIONS

    Directory of Open Access Journals (Sweden)

    N. I. Kulbashnaya

    2016-01-01

    Full Text Available The paper considers an application of entropy characteristics as criteria to coordinate traffic conditions at neighboring road sections. It has been proved that the entropy characteristics are widely used in the methods that take into account information influence of the environment on drivers and in the mechanisms that create such traffic conditions which ensure preservation of the optimal level of driver’s emotional tension during the drive. Solution of such problem is considered in the aspect of coordination of traffic conditions at neighboring road sections that, in its turn, is directed on exclusion of any driver’s transitional processes. Methodology for coordination of traffic conditions at neighboring road sections is based on the E. V. Gavrilov’s concept on coordination of some parameters of road sections which can be expressed in the entropy characteristics. The paper proposes to execute selection of coordination criteria according to accident rates because while moving along neighboring road sections traffic conditions change drastically that can result in creation of an accident situation. Relative organization of a driver’s perception field and driver’s interaction with the traffic environment has been selected as entropy characteristics. Therefore, the given characteristics are made conditional to the road accidents rate. The investigation results have revealed a strong correlation between the relative organization of the driver’s perception field and the relative organization of the driver’s interaction with the traffic environment and the accident rate. Results of the executed experiment have proved an influence of the accident rate on the investigated entropy characteristics.

  5. Do alcohol compliance checks decrease underage sales at neighboring establishments?

    Science.gov (United States)

    Erickson, Darin J; Smolenski, Derek J; Toomey, Traci L; Carlin, Bradley P; Wagenaar, Alexander C

    2013-11-01

    Underage alcohol compliance checks conducted by law enforcement agencies can reduce the likelihood of illegal alcohol sales at checked alcohol establishments, and theory suggests that an alcohol establishment that is checked may warn nearby establishments that compliance checks are being conducted in the area. In this study, we examined whether the effects of compliance checks diffuse to neighboring establishments. We used data from the Complying with the Minimum Drinking Age trial, which included more than 2,000 compliance checks conducted at more than 900 alcohol establishments. The primary outcome was the sale of alcohol to a pseudo-underage buyer without the need for age identification. A multilevel logistic regression was used to model the effect of a compliance check at each establishment as well as the effect of compliance checks at neighboring establishments within 500 m (stratified into four equal-radius concentric rings), after buyer, license, establishment, and community-level variables were controlled for. We observed a decrease in the likelihood of establishments selling alcohol to underage youth after they had been checked by law enforcement, but these effects quickly decayed over time. Establishments that had a close neighbor (within 125 m) checked in the past 90 days were also less likely to sell alcohol to young-appearing buyers. The spatial effect of compliance checks on other establishments decayed rapidly with increasing distance. Results confirm the hypothesis that the effects of police compliance checks do spill over to neighboring establishments. These findings have implications for the development of an optimal schedule of police compliance checks.

  6. Single cell transcriptomics of neighboring hyphae of Aspergillus niger

    Science.gov (United States)

    2011-01-01

    Single cell profiling was performed to assess differences in RNA accumulation in neighboring hyphae of the fungus Aspergillus niger. A protocol was developed to isolate and amplify RNA from single hyphae or parts thereof. Microarray analysis resulted in a present call for 4 to 7% of the A. niger genes, of which 12% showed heterogeneous RNA levels. These genes belonged to a wide range of gene categories. PMID:21816052

  7. [Galaxy/quasar classification based on nearest neighbor method].

    Science.gov (United States)

    Li, Xiang-Ru; Lu, Yu; Zhou, Jian-Ming; Wang, Yong-Jun

    2011-09-01

    With the wide application of high-quality CCD in celestial spectrum imagery and the implementation of many large sky survey programs (e. g., Sloan Digital Sky Survey (SDSS), Two-degree-Field Galaxy Redshift Survey (2dF), Spectroscopic Survey Telescope (SST), Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) program and Large Synoptic Survey Telescope (LSST) program, etc.), celestial observational data are coming into the world like torrential rain. Therefore, to utilize them effectively and fully, research on automated processing methods for celestial data is imperative. In the present work, we investigated how to recognizing galaxies and quasars from spectra based on nearest neighbor method. Galaxies and quasars are extragalactic objects, they are far away from earth, and their spectra are usually contaminated by various noise. Therefore, it is a typical problem to recognize these two types of spectra in automatic spectra classification. Furthermore, the utilized method, nearest neighbor, is one of the most typical, classic, mature algorithms in pattern recognition and data mining, and often is used as a benchmark in developing novel algorithm. For applicability in practice, it is shown that the recognition ratio of nearest neighbor method (NN) is comparable to the best results reported in the literature based on more complicated methods, and the superiority of NN is that this method does not need to be trained, which is useful in incremental learning and parallel computation in mass spectral data processing. In conclusion, the results in this work are helpful for studying galaxies and quasars spectra classification.

  8. Evidence for cultural differences between neighboring chimpanzee communities.

    Science.gov (United States)

    Luncz, Lydia V; Mundry, Roger; Boesch, Christophe

    2012-05-22

    The majority of evidence for cultural behavior in animals has come from comparisons between populations separated by large geographical distances that often inhabit different environments. The difficulty of excluding ecological and genetic variation as potential explanations for observed behaviors has led some researchers to challenge the idea of animal culture. Chimpanzees (Pan troglodytes verus) in the Taï National Park, Côte d'Ivoire, crack Coula edulis nuts using stone and wooden hammers and tree root anvils. In this study, we compare for the first time hammer selection for nut cracking across three neighboring chimpanzee communities that live in the same forest habitat, which reduces the likelihood of ecological variation. Furthermore, the study communities experience frequent dispersal of females at maturity, which eliminates significant genetic variation. We compared key ecological factors, such as hammer availability and nut hardness, between the three neighboring communities and found striking differences in group-specific hammer selection among communities despite similar ecological conditions. Differences were found in the selection of hammer material and hammer size in response to changes in nut resistance over time. Our findings highlight the subtleties of cultural differences in wild chimpanzees and illustrate how cultural knowledge is able to shape behavior, creating differences among neighboring social groups. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Coordinate determination of high energy charged particles by silicon strip detectors

    International Nuclear Information System (INIS)

    Anokhin, I.E.; Zinets, O.S.

    2002-01-01

    The coordinate determination accuracy of minimum ionizing and short-range particles by silicon strip detectors has been considered. The charge collection on neighboring strips of the detector is studied and the influence of diffusion and the electric field distribution on the accuracy of the coordinate determination is analyzed. It has been shown that coordinates of both minimum ionizing and short-range particles can be determined with accuracy to a few microns using silicon strip detectors. 11 refs.; 8 figs

  10. Buried oxide layer in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  11. Quality and efficiency in high dimensional Nearest neighbor search

    KAUST Repository

    Tao, Yufei; Yi, Ke; Sheng, Cheng; Kalnis, Panos

    2009-01-01

    Nearest neighbor (NN) search in high dimensional space is an important problem in many applications. Ideally, a practical solution (i) should be implementable in a relational database, and (ii) its query cost should grow sub-linearly with the dataset size, regardless of the data and query distributions. Despite the bulk of NN literature, no solution fulfills both requirements, except locality sensitive hashing (LSH). The existing LSH implementations are either rigorous or adhoc. Rigorous-LSH ensures good quality of query results, but requires expensive space and query cost. Although adhoc-LSH is more efficient, it abandons quality control, i.e., the neighbor it outputs can be arbitrarily bad. As a result, currently no method is able to ensure both quality and efficiency simultaneously in practice. Motivated by this, we propose a new access method called the locality sensitive B-tree (LSB-tree) that enables fast highdimensional NN search with excellent quality. The combination of several LSB-trees leads to a structure called the LSB-forest that ensures the same result quality as rigorous-LSH, but reduces its space and query cost dramatically. The LSB-forest also outperforms adhoc-LSH, even though the latter has no quality guarantee. Besides its appealing theoretical properties, the LSB-tree itself also serves as an effective index that consumes linear space, and supports efficient updates. Our extensive experiments confirm that the LSB-tree is faster than (i) the state of the art of exact NN search by two orders of magnitude, and (ii) the best (linear-space) method of approximate retrieval by an order of magnitude, and at the same time, returns neighbors with much better quality. © 2009 ACM.

  12. Mountain tourism development in Serbia and neighboring countries

    Directory of Open Access Journals (Sweden)

    Krunić Nikola

    2010-01-01

    Full Text Available Mountain areas with their surroundings are important parts of tourism regions with potentials for all-season tourism development and complementary activities. Development possibilities are based on size of high mountain territory, nature protection regimes, infrastructural equipment, provided conditions for leisure and recreation as well as involvement of local population in processes of development and protection. This paper analyses the key aspects of tourism development, winter tourism in high-mountain areas of Serbia and some neighboring countries (Slovakia, Romania, Bulgaria, and Greece. Common determinants of cohesion between nature protection and mountain tourism development, national development policies, applied models and concepts and importance of trans-border cooperation are indicated.

  13. Neighboring Structure Visualization on a Grid-based Layout.

    Science.gov (United States)

    Marcou, G; Horvath, D; Varnek, A

    2017-10-01

    Here, we describe an algorithm to visualize chemical structures on a grid-based layout in such a way that similar structures are neighboring. It is based on structure reordering with the help of the Hilbert Schmidt Independence Criterion, representing an empirical estimate of the Hilbert-Schmidt norm of the cross-covariance operator. The method can be applied to any layout of bi- or three-dimensional shape. The approach is demonstrated on a set of dopamine D5 ligands visualized on squared, disk and spherical layouts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. The nearest neighbor and the bayes error rates.

    Science.gov (United States)

    Loizou, G; Maybank, S J

    1987-02-01

    The (k, l) nearest neighbor method of pattern classification is compared to the Bayes method. If the two acceptance rates are equal then the asymptotic error rates satisfy the inequalities Ek,l + 1 ¿ E*(¿) ¿ Ek,l dE*(¿), where d is a function of k, l, and the number of pattern classes, and ¿ is the reject threshold for the Bayes method. An explicit expression for d is given which is optimal in the sense that for some probability distributions Ek,l and dE* (¿) are equal.

  15. Diagnostic tools for nearest neighbors techniques when used with satellite imagery

    Science.gov (United States)

    Ronald E. McRoberts

    2009-01-01

    Nearest neighbors techniques are non-parametric approaches to multivariate prediction that are useful for predicting both continuous and categorical forest attribute variables. Although some assumptions underlying nearest neighbor techniques are common to other prediction techniques such as regression, other assumptions are unique to nearest neighbor techniques....

  16. Using K-Nearest Neighbor in Optical Character Recognition

    Directory of Open Access Journals (Sweden)

    Veronica Ong

    2016-03-01

    Full Text Available The growth in computer vision technology has aided society with various kinds of tasks. One of these tasks is the ability of recognizing text contained in an image, or usually referred to as Optical Character Recognition (OCR. There are many kinds of algorithms that can be implemented into an OCR. The K-Nearest Neighbor is one such algorithm. This research aims to find out the process behind the OCR mechanism by using K-Nearest Neighbor algorithm; one of the most influential machine learning algorithms. It also aims to find out how precise the algorithm is in an OCR program. To do that, a simple OCR program to classify alphabets of capital letters is made to produce and compare real results. The result of this research yielded a maximum of 76.9% accuracy with 200 training samples per alphabet. A set of reasons are also given as to why the program is able to reach said level of accuracy.

  17. Kinetic Models for Topological Nearest-Neighbor Interactions

    Science.gov (United States)

    Blanchet, Adrien; Degond, Pierre

    2017-12-01

    We consider systems of agents interacting through topological interactions. These have been shown to play an important part in animal and human behavior. Precisely, the system consists of a finite number of particles characterized by their positions and velocities. At random times a randomly chosen particle, the follower, adopts the velocity of its closest neighbor, the leader. We study the limit of a system size going to infinity and, under the assumption of propagation of chaos, show that the limit kinetic equation is a non-standard spatial diffusion equation for the particle distribution function. We also study the case wherein the particles interact with their K closest neighbors and show that the corresponding kinetic equation is the same. Finally, we prove that these models can be seen as a singular limit of the smooth rank-based model previously studied in Blanchet and Degond (J Stat Phys 163:41-60, 2016). The proofs are based on a combinatorial interpretation of the rank as well as some concentration of measure arguments.

  18. Attribute Weighting Based K-Nearest Neighbor Using Gain Ratio

    Science.gov (United States)

    Nababan, A. A.; Sitompul, O. S.; Tulus

    2018-04-01

    K- Nearest Neighbor (KNN) is a good classifier, but from several studies, the result performance accuracy of KNN still lower than other methods. One of the causes of the low accuracy produced, because each attribute has the same effect on the classification process, while some less relevant characteristics lead to miss-classification of the class assignment for new data. In this research, we proposed Attribute Weighting Based K-Nearest Neighbor Using Gain Ratio as a parameter to see the correlation between each attribute in the data and the Gain Ratio also will be used as the basis for weighting each attribute of the dataset. The accuracy of results is compared to the accuracy acquired from the original KNN method using 10-fold Cross-Validation with several datasets from the UCI Machine Learning repository and KEEL-Dataset Repository, such as abalone, glass identification, haberman, hayes-roth and water quality status. Based on the result of the test, the proposed method was able to increase the classification accuracy of KNN, where the highest difference of accuracy obtained hayes-roth dataset is worth 12.73%, and the lowest difference of accuracy obtained in the abalone dataset of 0.07%. The average result of the accuracy of all dataset increases the accuracy by 5.33%.

  19. Structure and physical properties of silicon clusters and of vacancy clusters in bulk silicon

    International Nuclear Information System (INIS)

    Sieck, A.

    2000-01-01

    In this thesis the growth-pattern of free silicon clusters and vacancy clusters in bulk silicon is investigated. The aim is to describe and to better understand the cluster to bulk transition. Silicon structures in between clusters and solids feature new interesting physical properties. The structure and physical properties of silicon clusters can be revealed by a combination of theory and experiment, only. Low-energy clusters are determined with different optimization techniques and a density-functional based tight-binding method. Additionally, infrared and Raman spectra, and polarizabilities calculated within self-consistent field density-functional theory are provided for the smaller clusters. For clusters with 25 to 35 atoms an analysis of the shape of the clusters and the related mobilities in a buffer gas is given. Finally, the clusters observed in low-temperature experiments are identified via the best match between calculated properties and experimental data. Silicon clusters with 10 to 15 atoms have a tricapped trigonal prism as a common subunit. Clusters with up to about 25 atoms follow a prolate growth-path. In the range from 24 to 30 atoms the geometry of the clusters undergoes a transition towards compact spherical structures. Low-energy clusters with up to 240 atoms feature a bonding pattern strikingly different from the tetrahedral bonding in the solid. It follows that structures with dimensions of several Angstroem have electrical and optical properties different from the solid. The calculated stabilities and positron-lifetimes of vacancy clusters in bulk silicon indicate the positron-lifetimes of about 435 ps detected in irradiated silicon to be related to clusters of 9 or 10 vacancies. The vacancies in these clusters form neighboring hexa-rings and, therefore, minimize the number of dangling bonds. (orig.)

  20. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

  1. Enhanced Approximate Nearest Neighbor via Local Area Focused Search.

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, Antonio [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Blazier, Nicholas Paul [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-02-01

    Approximate Nearest Neighbor (ANN) algorithms are increasingly important in machine learning, data mining, and image processing applications. There is a large family of space- partitioning ANN algorithms, such as randomized KD-Trees, that work well in practice but are limited by an exponential increase in similarity comparisons required to optimize recall. Additionally, they only support a small set of similarity metrics. We present Local Area Fo- cused Search (LAFS), a method that enhances the way queries are performed using an existing ANN index. Instead of a single query, LAFS performs a number of smaller (fewer similarity comparisons) queries and focuses on a local neighborhood which is refined as candidates are identified. We show that our technique improves performance on several well known datasets and is easily extended to general similarity metrics using kernel projection techniques.

  2. Nearest Neighbor Estimates of Entropy for Multivariate Circular Distributions

    Directory of Open Access Journals (Sweden)

    Neeraj Misra

    2010-05-01

    Full Text Available In molecular sciences, the estimation of entropies of molecules is important for the understanding of many chemical and biological processes. Motivated by these applications, we consider the problem of estimating the entropies of circular random vectors and introduce non-parametric estimators based on circular distances between n sample points and their k th nearest neighbors (NN, where k (≤ n – 1 is a fixed positive integer. The proposed NN estimators are based on two different circular distances, and are proven to be asymptotically unbiased and consistent. The performance of one of the circular-distance estimators is investigated and compared with that of the already established Euclidean-distance NN estimator using Monte Carlo samples from an analytic distribution of six circular variables of an exactly known entropy and a large sample of seven internal-rotation angles in the molecule of tartaric acid, obtained by a realistic molecular-dynamics simulation.

  3. Introduction to machine learning: k-nearest neighbors.

    Science.gov (United States)

    Zhang, Zhongheng

    2016-06-01

    Machine learning techniques have been widely used in many scientific fields, but its use in medical literature is limited partly because of technical difficulties. k-nearest neighbors (kNN) is a simple method of machine learning. The article introduces some basic ideas underlying the kNN algorithm, and then focuses on how to perform kNN modeling with R. The dataset should be prepared before running the knn() function in R. After prediction of outcome with kNN algorithm, the diagnostic performance of the model should be checked. Average accuracy is the mostly widely used statistic to reflect the kNN algorithm. Factors such as k value, distance calculation and choice of appropriate predictors all have significant impact on the model performance.

  4. Measurement of near neighbor separations of surface atoms

    International Nuclear Information System (INIS)

    Cohen, P.I.

    Two techniques are being developed to measure the nearest neighbor distances of atoms at the surfaces of solids. Both measures extended fine structure in the excitation probability of core level electrons which are excited by an incident electron beam. This is an important problem because the structures of most surface systems are as yet unknown, even though the location of surface atoms is the basis for any quantitative understanding of the chemistry and physics of surfaces and interfaces. These methods would allow any laboratory to make in situ determinations of surface structure in conjunction with most other laboratory probes of surfaces. Each of these two techniques has different advantages; further, the combination of the two will increase confidence in the results by reducing systematic error in the data analysis

  5. Radionuclide content of an exhumed canyon vessel and neighboring soil

    International Nuclear Information System (INIS)

    Holcomb, H.P.

    1976-11-01

    The long-term hazard potential associated with burial of process equipment from radiochemical separations plants is being evaluated. As part of this evaluation, a feed adjustment tank was exhumed eighteen years after burial. The tank had been in service in the fuel reprocessing plant for twenty-nine months before it was retired. Assay of the exhumed tank indicated that 7 mg (0.4 mCi) of 239 Pu and 1 mCi of 137 Cs remained on its surfaces; 1.1 mg (0.07 mCi) 239 Pu, 0.4 mCi 137 Cs, and 3.5 mCi 90 Sr were found in neighboring soil. The vessel and surrounding soil have met the present guidelines (less than or equal to 10 nCi/g) of the U. S. Energy Research and Development Administration (ERDA) for nonretrievable waste

  6. Reduction of Conflicts in Mining Development Using "Good Neighbor Agreements"

    Science.gov (United States)

    Masaitis, A.

    2013-05-01

    New environmental and social challenges for the mining industry in both developed and developing countries show the obvious need to implement "responsible" mining practices that include improved community involvement. Good Neighbor Agreements (GNA's) are a relatively new mechanism for improving communication and trust between a mining company and the community. The focus of a GNA will be to provide a written and enforceable agreement, negotiated between the concerned public and the respective mining company to respond to concerns from the public, and also provide a mechanism for conflict resolution, when there is mutual benefit to maintain a working relationship. Development of GNA's, a recently evolving process that promotes environmentally sound relationships between mines and the surrounding communities. Modify and apply the resulting GNA formulas to the developing countries and countries with transitional economies. This is particularly important for countries that have poorly functioning regulatory systems that cannot guarantee a healthy and safe environment for the communities. The fundamental questions addressed by this research. 1. This is a three-year research project started in August 2012 at the University of Nevada, Reno (UNR) to develop a Good Neighbor Agreements standards as well as to investigate the details of mine development. 2. Identify spheres of possible cooperation between mining companies, government organizations, and the Non-Governmental Organizations (NGO's). Use this cooperation to develop international standards for the GNA, to promote exchange of environmental information, and exchange of successful environmental, health, and safety practices between mining operations from different countries. Discussion: The Good Neighbor Agreement currently evolving will address the following: 1. Provide an economically viable mechanism for developing a partnership between mining operations and the local communities that will increase mining industry

  7. Building good relationships with neighbors of Japan's oldest plant, Tsuruga

    International Nuclear Information System (INIS)

    Hata, Emi

    1992-01-01

    Since its establishment in 1957 as a pioneer company of nuclear power development in Japan, the Japan Atomic Power Company (JAPC) has gained a great deal of experience with construction and operation of four nuclear power plants - one gas-cooled reactor, two boiling water reactors (BWRs), and one pressurized water reactor (PWR) - at two sites, Tsuruga and Tokai. To gain the understanding and cooperation of the local community, the Tsuruga station must keep running. Each employee is encouraged to make every possible effort not only to ensure the safe and reliable operation of the two units, but also to ensure conscientious coexistence and coprosperity within the local community. The Tsuruga office in the city and the Public Relations (PR) Pavilion (visitor's center) at the site work together as an open window of communication with the local community. Under these basic philosophies, various good neighbor activities are developed and carried out

  8. Implementation of Nearest Neighbor using HSV to Identify Skin Disease

    Science.gov (United States)

    Gerhana, Y. A.; Zulfikar, W. B.; Ramdani, A. H.; Ramdhani, M. A.

    2018-01-01

    Today, Android is one of the most widely used operating system in the world. Most of android device has a camera that could capture an image, this feature could be optimized to identify skin disease. The disease is one of health problem caused by bacterium, fungi, and virus. The symptoms of skin disease usually visible. In this work, the symptoms that captured as image contains HSV in every pixel of the image. HSV can extracted and then calculate to earn euclidean value. The value compared using nearest neighbor algorithm to discover closer value between image testing and image training to get highest value that decide class label or type of skin disease. The testing result show that 166 of 200 or about 80% is accurate. There are some reasons that influence the result of classification model like number of image training and quality of android device’s camera.

  9. Neighboring Optimal Aircraft Guidance in a General Wind Environment

    Science.gov (United States)

    Jardin, Matthew R. (Inventor)

    2003-01-01

    Method and system for determining an optimal route for an aircraft moving between first and second waypoints in a general wind environment. A selected first wind environment is analyzed for which a nominal solution can be determined. A second wind environment is then incorporated; and a neighboring optimal control (NOC) analysis is performed to estimate an optimal route for the second wind environment. In particular examples with flight distances of 2500 and 6000 nautical miles in the presence of constant or piecewise linearly varying winds, the difference in flight time between a nominal solution and an optimal solution is 3.4 to 5 percent. Constant or variable winds and aircraft speeds can be used. Updated second wind environment information can be provided and used to obtain an updated optimal route.

  10. Morphological type correlation between nearest neighbor pairs of galaxies

    Science.gov (United States)

    Yamagata, Tomohiko

    1990-01-01

    Although the morphological type of galaxies is one of the most fundamental properties of galaxies, its origin and evolutionary processes, if any, are not yet fully understood. It has been established that the galaxy morphology strongly depends on the environment in which the galaxy resides (e.g., Dressler 1980). Galaxy pairs correspond to the smallest scales of galaxy clustering and may provide important clues to how the environment influences the formation and evolution of galaxies. Several investigators pointed out that there is a tendency for pair galaxies to have similar morphological types (Karachentsev and Karachentseva 1974, Page 1975, Noerdlinger 1979). Here, researchers analyze morphological type correlation for 18,364 nearest neighbor pairs of galaxies identified in the magnetic tape version of the Center for Astrophysics Redshift Catalogue.

  11. Designing lattice structures with maximal nearest-neighbor entanglement

    Energy Technology Data Exchange (ETDEWEB)

    Navarro-Munoz, J C; Lopez-Sandoval, R [Instituto Potosino de Investigacion CientIfica y Tecnologica, Camino a la presa San Jose 2055, 78216 San Luis Potosi (Mexico); Garcia, M E [Theoretische Physik, FB 18, Universitaet Kassel and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Str.40, 34132 Kassel (Germany)

    2009-08-07

    In this paper, we study the numerical optimization of nearest-neighbor concurrence of bipartite one- and two-dimensional lattices, as well as non-bipartite two-dimensional lattices. These systems are described in the framework of a tight-binding Hamiltonian while the optimization of concurrence was performed using genetic algorithms. Our results show that the concurrence of the optimized lattice structures is considerably higher than that of non-optimized systems. In the case of one-dimensional chains, the concurrence increases dramatically when the system begins to dimerize, i.e., it undergoes a structural phase transition (Peierls distortion). This result is consistent with the idea that entanglement is maximal or shows a singularity near quantum phase transitions. Moreover, the optimization of concurrence in two-dimensional bipartite and non-bipartite lattices is achieved when the structures break into smaller subsystems, which are arranged in geometrically distinguishable configurations.

  12. Credit scoring analysis using weighted k nearest neighbor

    Science.gov (United States)

    Mukid, M. A.; Widiharih, T.; Rusgiyono, A.; Prahutama, A.

    2018-05-01

    Credit scoring is a quatitative method to evaluate the credit risk of loan applications. Both statistical methods and artificial intelligence are often used by credit analysts to help them decide whether the applicants are worthy of credit. These methods aim to predict future behavior in terms of credit risk based on past experience of customers with similar characteristics. This paper reviews the weighted k nearest neighbor (WKNN) method for credit assessment by considering the use of some kernels. We use credit data from a private bank in Indonesia. The result shows that the Gaussian kernel and rectangular kernel have a better performance based on the value of percentage corrected classified whose value is 82.4% respectively.

  13. Radiative energy loss of neighboring subjets arXiv

    CERN Document Server

    Mehtar-Tani, Yacine

    We compute the in-medium energy loss probability distribution of two neighboring subjets at leading order, in the large-$N_c$ approximation. Our result exhibits a gradual onset of color decoherence of the system and accounts for two expected limiting cases. When the angular separation is smaller than the characteristic angle for medium-induced radiation, the two-pronged substructure lose energy coherently as a single color charge, namely that of the parent parton. At large angular separation the two subjets lose energy independently. Our result is a first step towards quantifying effects of energy loss as a result of the fluctuation of the multi-parton jet substructure and therefore goes beyond the standard approach to jet quenching based on single parton energy loss. We briefly discuss applications to jet observables in heavy-ion collisions.

  14. An interactive cooperation model for neighboring virtual power plants

    International Nuclear Information System (INIS)

    Shabanzadeh, Morteza; Sheikh-El-Eslami, Mohammad-Kazem; Haghifam, Mahmoud-Reza

    2017-01-01

    Highlights: •The trading strategies of a VPP in cooperation with its neighboring VPPs are addressed. •A portfolio of inter-regional contracts is considered to model this cooperation scheme. •A novel mathematical formulation for possible inadvertent transactions is provided. •A two-stage stochastic programming approach is applied to characterize the uncertainty. •Two efficient risk measures, SSD and CVaR, are implemented in the VPP decision-making problem. -- Abstract: Future distribution systems will accommodate an increasing share of distributed energy resources (DERs). Facing with this new reality, virtual power plants (VPPs) play a key role to aggregate DERs with the aim of facilitating their involvement in wholesale electricity markets. In this paper, the trading strategies of a VPP in cooperation with its neighboring VPPs are addressed. Toward this aim, a portfolio of inter-regional contracts is considered to model this cooperation and maximize the energy trade opportunities of the VPP within a medium-term horizon. To hedge against profit variability caused by market price uncertainties, two efficient risk management approaches are also implemented in the VPP decision-making problem based on the concepts of conditional value at risk (CVaR) and second-order stochastic dominance constraints (SSD). The resulting models are formulated as mixed-integer linear programming (MILP) problems that can be solved using off-the-shelf software packages. The efficiency of the proposed risk-hedging models is analyzed through a detailed case study, and thereby relevant conclusions are drawn.

  15. Silicon heterojunction transistor

    International Nuclear Information System (INIS)

    Matsushita, T.; Oh-uchi, N.; Hayashi, H.; Yamoto, H.

    1979-01-01

    SIPOS (Semi-insulating polycrystalline silicon) which is used as a surface passivation layer for highly reliable silicon devices constitutes a good heterojunction for silicon. P- or B-doped SIPOS has been used as the emitter material of a heterojunction transistor with the base and collector of silicon. An npn SIPOS-Si heterojunction transistor showing 50 times the current gain of an npn silicon homojunction transistor has been realized by high-temperature treatments in nitrogen and low-temperature annealing in hydrogen or forming gas

  16. The chemistry of silicon

    CERN Document Server

    Rochow, E G; Emeléus, H J; Nyholm, Ronald

    1975-01-01

    Pergamon Texts in Organic Chemistry, Volume 9: The Chemistry of Silicon presents information essential in understanding the chemical properties of silicon. The book first covers the fundamental aspects of silicon, such as its nuclear, physical, and chemical properties. The text also details the history of silicon, its occurrence and distribution, and applications. Next, the selection enumerates the compounds and complexes of silicon, along with organosilicon compounds. The text will be of great interest to chemists and chemical engineers. Other researchers working on research study involving s

  17. Silicon Microspheres Photonics

    International Nuclear Information System (INIS)

    Serpenguzel, A.

    2008-01-01

    Electrophotonic integrated circuits (EPICs), or alternatively, optoelectronic integrated circuit (OEICs) are the natural evolution of the microelectronic integrated circuit (IC) with the addition of photonic capabilities. Traditionally, the IC industry has been based on group IV silicon, whereas the photonics industry on group III-V semiconductors. However, silicon based photonic microdevices have been making strands in siliconizing photonics. Silicon microspheres with their high quality factor whispering gallery modes (WGMs), are ideal candidates for wavelength division multiplexing (WDM) applications in the standard near-infrared communication bands. In this work, we will discuss the possibility of using silicon microspheres for photonics applications in the near-infrared

  18. Unwanted Behaviors and Nuisance Behaviors Among Neighbors in a Belgian Community Sample.

    Science.gov (United States)

    Michaux, Emilie; Groenen, Anne; Uzieblo, Katarzyna

    2015-06-30

    Unwanted behaviors between (ex-)intimates have been extensively studied, while those behaviors within other contexts such as neighbors have received much less scientific consideration. Research indicates that residents are likely to encounter problem behaviors from their neighbors. Besides the lack of clarity in the conceptualization of problem behaviors among neighbors, little is known on which types of behaviors characterize neighbor problems. In this study, the occurrence of two types of problem behaviors encountered by neighbors was explored within a Belgian community sample: unwanted behaviors such as threats and neighbor nuisance issues such as noise nuisance. By clearly distinguishing those two types of behaviors, this study aimed at contributing to the conceptualization of neighbor problems. Next, the coping strategies used to deal with the neighbor problems were investigated. Our results indicated that unwanted behaviors were more frequently encountered by residents compared with nuisance problems. Four out of 10 respondents reported both unwanted pursuit behavior and nuisance problems. It was especially unlikely to encounter nuisance problems in isolation of unwanted pursuit behaviors. While different coping styles (avoiding the neighbor, confronting the neighbor, and enlisting help from others) were equally used by the stalked participants, none of them was perceived as being more effective in reducing the stalking behaviors. Strikingly, despite being aware of specialized help services such as community mediation services, only a very small subgroup enlisted this kind of professional help. © The Author(s) 2015.

  19. Comparison of confinement characters between porous silicon and silicon nanowires

    International Nuclear Information System (INIS)

    Tit, Nacir; Yamani, Zain H.; Pizzi, Giovanni; Virgilio, Michele

    2011-01-01

    Confinement character and its effects on photoluminescence (PL) properties are theoretically investigated and compared between porous silicon (p-Si) and silicon nanowires (Si-NWs). The method is based on the application of the tight-binding technique using the minimal sp 3 -basis set, including the second-nearest-neighbor interactions. The results show that the quantum confinement (QC) is not entirely controlled by the porosity, rather it is mainly affected by the average distance between pores (d). The p-Si is found to exhibit weaker confinement character than Si-NWs. The confinement energy of charge carriers decays against d exponentially for p-Si and via a power-law for Si-NWs. This latter type of QC is much stronger and is somewhat similar to the case of a single particle in a quantum box. The excellent fit to the PL data demonstrates that the experimental samples of p-Si do exhibit strong QC character and thus reveals the possibility of silicon clustering into nano-crystals and/or nanowires. Furthermore, the results show that the passivation of the surface dangling bonds by the hydrogen atoms plays an essential role in preventing the appearance of gap states and consequently enhances the optical qualities of the produced structures. The oscillator strength (OS) is found to increase exponentially with energy in Si-NWs confirming the strong confinement character of carriers. Our theoretical findings suggest the existence of Si nanocrystals (Si-NCs) of sizes 1-3 nm and/or Si-NWs of cross-sectional sizes in the 1-3 nm range inside the experimental p-Si samples. The experimentally-observed strong photoluminescence from p-Si should be in favor of an exhibition of 3D-confinement character. The favorable comparison of our theoretical results with the experimental data consolidates our above claims. -- Highlights: → Tight-binding is used to study quantum-confinement (QC) effects in p-Si and Si-NWs. → QC is not entirely controlled by the porosity but also by the d

  20. Unsynchronized influenza epidemics in two neighboring subtropical cities

    Directory of Open Access Journals (Sweden)

    Xiujuan Tang

    2018-04-01

    Full Text Available Objective: The aim of this study was to examine the synchrony of influenza epidemics between Hong Kong and Shenzhen, two neighboring subtropical cities in South China. Methods: Laboratory-confirmed influenza data for the period January 2006 to December 2016 were obtained from the Shenzhen Center for Disease Control and Prevention and the Department of Health in Hong Kong. The population data were retrieved from the 2011 population censuses. The weekly rates of laboratory-confirmed influenza cases were compared between Shenzhen and Hong Kong. Results: Unsynchronized influenza epidemics between Hong Kong and Shenzhen were frequently observed during the study period. Influenza A/H1N1 caused a more severe pandemic in Hong Kong in 2009, but the subsequent seasonal epidemics showed similar magnitudes in both cities. Two influenza A/H3N2 dominant epidemic waves were seen in Hong Kong in 2015, but these epidemics were very minor in Shenzhen. More influenza B epidemics occurred in Shenzhen than in Hong Kong. Conclusions: Influenza epidemics appeared to be unsynchronized between Hong Kong and Shenzhen most of the time. Given the close geographical locations of these two cities, this could be due to the strikingly different age structures of their populations. Keywords: Influenza epidemics, Synchrony, Shenzhen, Hong Kong

  1. Forecasting of steel consumption with use of nearest neighbors method

    Directory of Open Access Journals (Sweden)

    Rogalewicz Michał

    2017-01-01

    Full Text Available In the process of building a steel construction, its design is usually commissioned to the design office. Then a quotation is made and the finished offer is delivered to the customer. Its final shape is influenced by steel consumption to a great extent. Correct determination of the potential consumption of this material most often determines the profitability of the project. Because of a long waiting time for a final project from the design office, it is worthwhile to pre-analyze the project’s profitability and feasibility using historical data on already realized orders. The paper presents an innovative approach to decision-making support in one of the Polish construction companies. The authors have defined and prioritized the most important factors that differentiate the executed orders and have the greatest impact on steel consumption. These are, among others: height and width of steel structure, number of aisles, type of roof, etc. Then they applied and adapted the method of k-nearest neighbors to the specificity of the discussed problem. The goal was to search a set of historical orders and find the most similar to the analyzed one. On this basis, consumption of steel can be estimated. The method was programmed within the EXPLOR application.

  2. Identification of influential users by neighbors in online social networks

    Science.gov (United States)

    Sheikhahmadi, Amir; Nematbakhsh, Mohammad Ali; Zareie, Ahmad

    2017-11-01

    Identification and ranking of influential users in social networks for the sake of news spreading and advertising has recently become an attractive field of research. Given the large number of users in social networks and also the various relations that exist among them, providing an effective method to identify influential users has been gradually considered as an essential factor. In most of the already-provided methods, those users who are located in an appropriate structural position of the network are regarded as influential users. These methods do not usually pay attention to the interactions among users, and also consider those relations as being binary in nature. This paper, therefore, proposes a new method to identify influential users in a social network by considering those interactions that exist among the users. Since users tend to act within the frame of communities, the network is initially divided into different communities. Then the amount of interaction among users is used as a parameter to set the weight of relations existing within the network. Afterward, by determining the neighbors' role for each user, a two-level method is proposed for both detecting users' influence and also ranking them. Simulation and experimental results on twitter data shows that those users who are selected by the proposed method, comparing to other existing ones, are distributed in a more appropriate distance. Moreover, the proposed method outperforms the other ones in terms of both the influential speed and capacity of the users it selects.

  3. k-Nearest Neighbors Algorithm in Profiling Power Analysis Attacks

    Directory of Open Access Journals (Sweden)

    Z. Martinasek

    2016-06-01

    Full Text Available Power analysis presents the typical example of successful attacks against trusted cryptographic devices such as RFID (Radio-Frequency IDentifications and contact smart cards. In recent years, the cryptographic community has explored new approaches in power analysis based on machine learning models such as Support Vector Machine (SVM, RF (Random Forest and Multi-Layer Perceptron (MLP. In this paper, we made an extensive comparison of machine learning algorithms in the power analysis. For this purpose, we implemented a verification program that always chooses the optimal settings of individual machine learning models in order to obtain the best classification accuracy. In our research, we used three datasets, the first containing the power traces of an unprotected AES (Advanced Encryption Standard implementation. The second and third datasets are created independently from public available power traces corresponding to a masked AES implementation (DPA Contest v4. The obtained results revealed some interesting facts, namely, an elementary k-NN (k-Nearest Neighbors algorithm, which has not been commonly used in power analysis yet, shows great application potential in practice.

  4. River Flow Prediction Using the Nearest Neighbor Probabilistic Ensemble Method

    Directory of Open Access Journals (Sweden)

    H. Sanikhani

    2016-02-01

    Full Text Available Introduction: In the recent years, researchers interested on probabilistic forecasting of hydrologic variables such river flow.A probabilistic approach aims at quantifying the prediction reliability through a probability distribution function or a prediction interval for the unknown future value. The evaluation of the uncertainty associated to the forecast is seen as a fundamental information, not only to correctly assess the prediction, but also to compare forecasts from different methods and to evaluate actions and decisions conditionally on the expected values. Several probabilistic approaches have been proposed in the literature, including (1 methods that use resampling techniques to assess parameter and model uncertainty, such as the Metropolis algorithm or the Generalized Likelihood Uncertainty Estimation (GLUE methodology for an application to runoff prediction, (2 methods based on processing the forecast errors of past data to produce the probability distributions of future values and (3 methods that evaluate how the uncertainty propagates from the rainfall forecast to the river discharge prediction, as the Bayesian forecasting system. Materials and Methods: In this study, two different probabilistic methods are used for river flow prediction.Then the uncertainty related to the forecast is quantified. One approach is based on linear predictors and in the other, nearest neighbor was used. The nonlinear probabilistic ensemble can be used for nonlinear time series analysis using locally linear predictors, while NNPE utilize a method adapted for one step ahead nearest neighbor methods. In this regard, daily river discharge (twelve years of Dizaj and Mashin Stations on Baranduz-Chay basin in west Azerbijan and Zard-River basin in Khouzestan provinces were used, respectively. The first six years of data was applied for fitting the model. The next three years was used to calibration and the remained three yeas utilized for testing the models

  5. Nearest neighbor 3D segmentation with context features

    Science.gov (United States)

    Hristova, Evelin; Schulz, Heinrich; Brosch, Tom; Heinrich, Mattias P.; Nickisch, Hannes

    2018-03-01

    Automated and fast multi-label segmentation of medical images is challenging and clinically important. This paper builds upon a supervised machine learning framework that uses training data sets with dense organ annotations and vantage point trees to classify voxels in unseen images based on similarity of binary feature vectors extracted from the data. Without explicit model knowledge, the algorithm is applicable to different modalities and organs, and achieves high accuracy. The method is successfully tested on 70 abdominal CT and 42 pelvic MR images. With respect to ground truth, an average Dice overlap score of 0.76 for the CT segmentation of liver, spleen and kidneys is achieved. The mean score for the MR delineation of bladder, bones, prostate and rectum is 0.65. Additionally, we benchmark several variations of the main components of the method and reduce the computation time by up to 47% without significant loss of accuracy. The segmentation results are - for a nearest neighbor method - surprisingly accurate, robust as well as data and time efficient.

  6. Chiral silicon nanostructures

    International Nuclear Information System (INIS)

    Schubert, E.; Fahlteich, J.; Hoeche, Th.; Wagner, G.; Rauschenbach, B.

    2006-01-01

    Glancing angle ion beam assisted deposition is used for the growth of amorphous silicon nanospirals onto [0 0 1] silicon substrates in a temperature range from room temperature to 475 deg. C. The nanostructures are post-growth annealed in an argon atmosphere at various temperatures ranging from 400 deg. C to 800 deg. C. Recrystallization of silicon within the persisting nanospiral configuration is demonstrated for annealing temperatures above 800 deg. C. Transmission electron microscopy and Raman spectroscopy are used to characterize the silicon samples prior and after temperature treatment

  7. Silicon web process development

    Science.gov (United States)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.

    1981-01-01

    The silicon web process takes advantage of natural crystallographic stabilizing forces to grow long, thin single crystal ribbons directly from liquid silicon. The ribbon, or web, is formed by the solidification of a liquid film supported by surface tension between two silicon filaments, called dendrites, which border the edges of the growing strip. The ribbon can be propagated indefinitely by replenishing the liquid silicon as it is transformed to crystal. The dendritic web process has several advantages for achieving low cost, high efficiency solar cells. These advantages are discussed.

  8. Phagocytic response of astrocytes to damaged neighboring cells.

    Directory of Open Access Journals (Sweden)

    Nicole M Wakida

    Full Text Available This study aims to understand the phagocytic response of astrocytes to the injury of neurons or other astrocytes at the single cell level. Laser nanosurgery was used to damage individual cells in both primary mouse cortical astrocytes and an established astrocyte cell line. In both cases, the release of material/substances from laser-irradiated astrocytes or neurons induced a phagocytic response in near-by astrocytes. Propidium iodide stained DNA originating from irradiated cells was visible in vesicles of neighboring cells, confirming phagocytosis of material from damaged cortical cells. In the presence of an intracellular pH indicator dye, newly formed vesicles correspond to acidic pH fluorescence, thus suggesting lysosome bound degradation of cellular debris. Cells with shared membrane connections prior to laser damage had a significantly higher frequency of induced phagocytosis compared to isolated cells with no shared membrane. The increase in phagocytic response of cells with a shared membrane occurred regardless of the extent of shared membrane (a thin filopodial connection vs. a cell cluster with significant shared membrane. In addition to the presence (or lack of a membrane connection, variation in phagocytic ability was also observed with differences in injury location within the cell and distance separating isolated astrocytes. These results demonstrate the ability of an astrocyte to respond to the damage of a single cell, be it another astrocyte, or a neuron. This single-cell level of analysis results in a better understanding of the role of astrocytes to maintain homeostasis in the CNS, particularly in the sensing and removal of debris in damaged or pathologic nervous tissue.

  9. Detect thy neighbor: Identity recognition at the root level in plants

    NARCIS (Netherlands)

    Chen, B.J.W.; During, H.J.; Anten, N.P.R.

    2012-01-01

    Some plant species increase root allocation at the expense of reproduction in the presence of non-self and non-kin neighbors, indicating the capacity of neighbor-identityrecognition at the rootlevel. Yet in spite of the potential consequences of rootidentityrecognition for the relationship between

  10. Working with Family, Friend, and Neighbor Caregivers: Lessons from Four Diverse Communities

    Science.gov (United States)

    Powell, Douglas R.

    2011-01-01

    This article is excerpted from "Who's Watching the Babies? Improving the Quality of Family, Friend, and Neighbor Care" by Douglas R. Powell ("ZERO TO THREE," 2008). The article explores questions about program development and implementation strategies for supporting Family, Friend, and Neighbor (FFN) caregivers: How do programs and their host…

  11. Characteristics of Broadband Seismic Noise in Taiwan and Neighboring Islands

    Science.gov (United States)

    Chen, Ching-Wei; Rau, Ruey-Juin

    2017-04-01

    We used seismic waveform data from 115 broad-band stations of BATS (Institute of Earth Science, Academia Sinica) and Central Weather Bureau Seismic Network from 2012 to 2016 for noise-level mapping in Taiwan and neighboring islands. We computed Power Spectral Density (PSD) for each station and analyzed long-term variance of microseism energy and polarizations of noise for severe weather events. The island of Taiwan is surrounded by ocean and the Central Range which has the highest peak Jade Mountain at 3,952 meters height occupies more than 66% of the island and departs it into the east and west coasts. The geographic settings then result in the high population density in the western plain and northern Taiwan. The dominant noise source in the microseism band (periods from 4-20 seconds) is the coupling between the near-coast ocean and sea floor which produces the high noise of averaging -130 dB along the west coastal area. In the eastern volcanic-arc coastal areas, the noise level is about 7% smaller than the west coast due to its deeper offshore water depth. As for the shorter periods (0.1-0.25 seconds) band, the so-called culture noise, an anthropic activity variance with the highest -103 dB can be identified in the metropolitan areas, such as the Taipei city and the noise level in the Central Range area is averaging -138 dB. Moreover, the noise also shows a daily and temporal evolution mainly related to the traffic effect. Furthermore, we determined the noise level for the entire island of Taiwan during 26-28 September, 2016, when the typhoon Megi hit the island and retrieved the enhancement of secondary microseism energy for each stations. Typhoon Megi landed in eastern and central Taiwan and reached the maximum wind speed of 45m/s in the surrounded eyewall. The Central Range, as a barrier, decreased the wind speed in southern Taiwan making an enhancement less than 10 dB, while in northern Taiwan where the direction the typhoon headed to, can reach more than 35

  12. Accelerating distributed average consensus by exploring the information of second-order neighbors

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Deming [School of Automation, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu (China); Xu Shengyuan, E-mail: syxu02@yahoo.com.c [School of Automation, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu (China); Zhao Huanyu [School of Automation, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu (China); Chu Yuming [Department of Mathematics, Huzhou Teacher' s College, Huzhou 313000, Zhejiang (China)

    2010-05-17

    The problem of accelerating distributed average consensus by using the information of second-order neighbors in both the discrete- and continuous-time cases is addressed in this Letter. In both two cases, when the information of second-order neighbors is used in each iteration, the network will converge with a speed faster than the algorithm only using the information of first-order neighbors. Moreover, the problem of using partial information of second-order neighbors is considered, and the edges are not chosen randomly from second-order neighbors. In the continuous-time case, the edges are chosen by solving a convex optimization problem which is formed by using the convex relaxation method. In the discrete-time case, for small network the edges are chosen optimally via the brute force method. Finally, simulation examples are provided to demonstrate the effectiveness of the proposed algorithm.

  13. Periodically poled silicon

    Science.gov (United States)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  14. Nonlinear silicon photonics

    Science.gov (United States)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  15. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  16. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed

    2014-07-29

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  17. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed; Rubin, Andrew; Refaat, Mohamed; Sedky, Sherif; Abdo, Mohammad

    2014-01-01

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  18. Nearest Neighbor Search in the Metric Space of a Complex Network for Community Detection

    Directory of Open Access Journals (Sweden)

    Suman Saha

    2016-03-01

    Full Text Available The objective of this article is to bridge the gap between two important research directions: (1 nearest neighbor search, which is a fundamental computational tool for large data analysis; and (2 complex network analysis, which deals with large real graphs but is generally studied via graph theoretic analysis or spectral analysis. In this article, we have studied the nearest neighbor search problem in a complex network by the development of a suitable notion of nearness. The computation of efficient nearest neighbor search among the nodes of a complex network using the metric tree and locality sensitive hashing (LSH are also studied and experimented. For evaluation of the proposed nearest neighbor search in a complex network, we applied it to a network community detection problem. Experiments are performed to verify the usefulness of nearness measures for the complex networks, the role of metric tree and LSH to compute fast and approximate node nearness and the the efficiency of community detection using nearest neighbor search. We observed that nearest neighbor between network nodes is a very efficient tool to explore better the community structure of the real networks. Several efficient approximation schemes are very useful for large networks, which hardly made any degradation of results, whereas they save lot of computational times, and nearest neighbor based community detection approach is very competitive in terms of efficiency and time.

  19. Neighboring trees affect ectomycorrhizal fungal community composition in a woodland-forest ecotone.

    Science.gov (United States)

    Hubert, Nathaniel A; Gehring, Catherine A

    2008-09-01

    Ectomycorrhizal fungi (EMF) are frequently species rich and functionally diverse; yet, our knowledge of the environmental factors that influence local EMF diversity and species composition remains poor. In particular, little is known about the influence of neighboring plants on EMF community structure. We tested the hypothesis that the EMF of plants with heterospecific neighbors would differ in species richness and community composition from the EMF of plants with conspecific neighbors. We conducted our study at the ecotone between pinyon (Pinus edulis)-juniper (Juniperus monosperma) woodland and ponderosa pine (Pinus ponderosa) forest in northern Arizona, USA where the dominant trees formed associations with either EMF (P. edulis and P. ponderosa) or arbuscular mycorrhizal fungi (AMF; J. monosperma). We also compared the EMF communities of pinyon and ponderosa pines where their rhizospheres overlapped. The EMF community composition, but not species richness of pinyon pines was significantly influenced by neighboring AM juniper, but not by neighboring EM ponderosa pine. Ponderosa pine EMF communities were different in species composition when growing in association with pinyon pine than when growing in association with a conspecific. The EMF communities of pinyon and ponderosa pines were similar where their rhizospheres overlapped consisting of primarily the same species in similar relative abundance. Our findings suggest that neighboring tree species identity shaped EMF community structure, but that these effects were specific to host-neighbor combinations. The overlap in community composition between pinyon pine and ponderosa pine suggests that these tree species may serve as reservoirs of EMF inoculum for one another.

  20. Process for making silicon

    Science.gov (United States)

    Levin, Harry (Inventor)

    1987-01-01

    A reactor apparatus (10) adapted for continuously producing molten, solar grade purity elemental silicon by thermal reaction of a suitable precursor gas, such as silane (SiH.sub.4), is disclosed. The reactor apparatus (10) includes an elongated reactor body (32) having graphite or carbon walls which are heated to a temperature exceeding the melting temperature of silicon. The precursor gas enters the reactor body (32) through an efficiently cooled inlet tube assembly (22) and a relatively thin carbon or graphite septum (44). The septum (44), being in contact on one side with the cooled inlet (22) and the heated interior of the reactor (32) on the other side, provides a sharp temperature gradient for the precursor gas entering the reactor (32) and renders the operation of the inlet tube assembly (22) substantially free of clogging. The precursor gas flows in the reactor (32) in a substantially smooth, substantially axial manner. Liquid silicon formed in the initial stages of the thermal reaction reacts with the graphite or carbon walls to provide a silicon carbide coating on the walls. The silicon carbide coated reactor is highly adapted for prolonged use for production of highly pure solar grade silicon. Liquid silicon (20) produced in the reactor apparatus (10) may be used directly in a Czochralski or other crystal shaping equipment.

  1. Hydrogen in amorphous silicon

    International Nuclear Information System (INIS)

    Peercy, P.S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH 1 ) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon

  2. Transformational silicon electronics

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-02-25

    In today\\'s traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100) wafers. Ninety percent of global electronics are made up of silicon. Therefore, we have developed a generic low-cost regenerative batch fabrication process to transform such wafers full of devices into thin (5 μm), mechanically flexible, optically semitransparent silicon fabric with devices, then recycling the remaining wafer to generate multiple silicon fabric with chips and devices, ensuring low-cost and optimal utilization of the whole substrate. We show monocrystalline, amorphous, and polycrystalline silicon and silicon dioxide fabric, all from low-cost bulk silicon (100) wafers with the semiconductor industry\\'s most advanced high-κ/metal gate stack based high-performance, ultra-low-power capacitors, field effect transistors, energy harvesters, and storage to emphasize the effectiveness and versatility of this process to transform traditional electronics into flexible and semitransparent ones for multipurpose applications. © 2014 American Chemical Society.

  3. Reduction in predator defense in the presence of neighbors in a colonial fish.

    Directory of Open Access Journals (Sweden)

    Franziska C Schädelin

    Full Text Available Predation pressure has long been considered a leading explanation of colonies, where close neighbors may reduce predation via dilution, alarming or group predator attacks. Attacking predators may be costly in terms of energy and survival, leading to the question of how neighbors contribute to predator deterrence in relationship to each other. Two hypotheses explaining the relative efforts made by neighbors are byproduct-mutualism, which occurs when breeders inadvertently attack predators by defending their nests, and reciprocity, which occurs when breeders deliberately exchange predator defense efforts with neighbors. Most studies investigating group nest defense have been performed with birds. However, colonial fish may constitute a more practical model system for an experimental approach because of the greater ability of researchers to manipulate their environment. We investigated in the colonial fish, Neolamprologus caudopunctatus, whether prospecting pairs preferred to breed near conspecifics or solitarily, and how breeders invested in anti-predator defense in relation to neighbors. In a simple choice test, prospecting pairs selected breeding sites close to neighbors versus a solitary site. Predators were then sequentially presented to the newly established test pairs, the previously established stimulus pairs or in between the two pairs. Test pairs attacked the predator eight times more frequently when they were presented on their non-neighbor side compared to between the two breeding sites, where stimulus pairs maintained high attack rates. Thus, by joining an established pair, test pairs were able to reduce their anti-predator efforts near neighbors, at no apparent cost to the stimulus pairs. These findings are unlikely to be explained by reciprocity or byproduct-mutualism. Our results instead suggest a commensal relationship in which new pairs exploit the high anti-predator efforts of established pairs, which invest similarly with or

  4. The Application of Determining Students’ Graduation Status of STMIK Palangkaraya Using K-Nearest Neighbors Method

    Science.gov (United States)

    Rusdiana, Lili; Marfuah

    2017-12-01

    K-Nearest Neighbors method is one of methods used for classification which calculate a value to find out the closest in distance. It is used to group a set of data such as students’ graduation status that are got from the amount of course credits taken by them, the grade point average (AVG), and the mini-thesis grade. The study is conducted to know the results of using K-Nearest Neighbors method on the application of determining students’ graduation status, so it can be analyzed from the method used, the data, and the application constructed. The aim of this study is to find out the application results by using K-Nearest Neighbors concept to determine students’ graduation status using the data of STMIK Palangkaraya students. The development of the software used Extreme Programming, since it was appropriate and precise for this study which was to quickly finish the project. The application was created using Microsoft Office Excel 2007 for the training data and Matlab 7 to implement the application. The result of K-Nearest Neighbors method on the application of determining students’ graduation status was 92.5%. It could determine the predicate graduation of 94 data used from the initial data before the processing as many as 136 data which the maximal training data was 50data. The K-Nearest Neighbors method is one of methods used to group a set of data based on the closest value, so that using K-Nearest Neighbors method agreed with this study. The results of K-Nearest Neighbors method on the application of determining students’ graduation status was 92.5% could determine the predicate graduation which is the maximal training data. The K-Nearest Neighbors method is one of methods used to group a set of data based on the closest value, so that using K-Nearest Neighbors method agreed with this study.

  5. Silicon micromachined vibrating gyroscopes

    Science.gov (United States)

    Voss, Ralf

    1997-09-01

    This work gives an overview of silicon micromachined vibrating gyroscopes. Market perspectives and fields of application are pointed out. The advantage of using silicon micromachining is discussed and estimations of the desired performance, especially for automobiles are given. The general principle of vibrating gyroscopes is explained. Vibrating silicon gyroscopes can be divided into seven classes. for each class the characteristic principle is presented and examples are given. Finally a specific sensor, based on a tuning fork for automotive applications with a sensitivity of 250(mu) V/degrees is described in detail.

  6. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  7. Silicon etch process

    International Nuclear Information System (INIS)

    Day, D.J.; White, J.C.

    1984-01-01

    A silicon etch process wherein an area of silicon crystal surface is passivated by radiation damage and non-planar structure produced by subsequent anisotropic etching. The surface may be passivated by exposure to an energetic particle flux - for example an ion beam from an arsenic, boron, phosphorus, silicon or hydrogen source, or an electron beam. Radiation damage may be used for pattern definition and/or as an etch stop. Ethylenediamine pyrocatechol or aqueous potassium hydroxide anisotropic etchants may be used. The radiation damage may be removed after etching by thermal annealing. (author)

  8. Silicon integrated circuit process

    International Nuclear Information System (INIS)

    Lee, Jong Duck

    1985-12-01

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  9. Silicon integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Duck

    1985-12-15

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  10. Silicon nanowire hybrid photovoltaics

    KAUST Repository

    Garnett, Erik C.; Peters, Craig; Brongersma, Mark; Cui, Yi; McGehee, Mike

    2010-01-01

    Silicon nanowire Schottky junction solar cells have been fabricated using n-type silicon nanowire arrays and a spin-coated conductive polymer (PEDOT). The polymer Schottky junction cells show superior surface passivation and open-circuit voltages compared to standard diffused junction cells with native oxide surfaces. External quantum efficiencies up to 88% were measured for these silicon nanowire/PEDOT solar cells further demonstrating excellent surface passivation. This process avoids high temperature processes which allows for low-cost substrates to be used. © 2010 IEEE.

  11. Silicon nanowire hybrid photovoltaics

    KAUST Repository

    Garnett, Erik C.

    2010-06-01

    Silicon nanowire Schottky junction solar cells have been fabricated using n-type silicon nanowire arrays and a spin-coated conductive polymer (PEDOT). The polymer Schottky junction cells show superior surface passivation and open-circuit voltages compared to standard diffused junction cells with native oxide surfaces. External quantum efficiencies up to 88% were measured for these silicon nanowire/PEDOT solar cells further demonstrating excellent surface passivation. This process avoids high temperature processes which allows for low-cost substrates to be used. © 2010 IEEE.

  12. Effects of second neighbor interactions on skyrmion lattices in chiral magnets

    International Nuclear Information System (INIS)

    Oliveira, E A S; Silva, R L; Silva, R C; Pereira, A R

    2017-01-01

    In this paper we investigate the influences of the second neighbor interactions on a skyrmion lattice in two-dimensional chiral magnets. Such a system contains the exchange and the Dzyaloshinskii–Moriya for the spin interactions and therefore, we analyse three situations: firstly, the second neighbor interaction is present only in the exchange coupling; secondly, it is present only in the Dzyaloshinskii–Moriya coupling. Finally, the second neighbor interactions are present in both exchange and Dzyaloshinskii–Moriya couplings. We show that such effects cause important modifications to the helical and skyrmion phases when an external magnetic field is applied. (paper)

  13. Improving Recommendations in Tag-based Systems with Spectral Clustering of Tag Neighbors

    DEFF Research Database (Denmark)

    Pan, Rong; Xu, Guandong; Dolog, Peter

    2012-01-01

    Tag as a useful metadata reflects the collaborative and conceptual features of documents in social collaborative annotation systems. In this paper, we propose a collaborative approach for expanding tag neighbors and investigate the spectral clustering algorithm to filter out noisy tag neighbors...... in order to get appropriate recommendation for users. The preliminary experiments have been conducted on MovieLens dataset to compare our proposed approach with the traditional collaborative filtering recommendation approach and naive tag neighbors expansion approach in terms of precision, and the result...... demonstrates that our approach could considerably improve the performance of recommendations....

  14. Joining elements of silicon carbide

    International Nuclear Information System (INIS)

    Olson, B.A.

    1979-01-01

    A method of joining together at least two silicon carbide elements (e.g.in forming a heat exchanger) is described, comprising subjecting to sufficiently non-oxidizing atmosphere and sufficiently high temperature, material placed in space between the elements. The material consists of silicon carbide particles, carbon and/or a precursor of carbon, and silicon, such that it forms a joint joining together at least two silicon carbide elements. At least one of the elements may contain silicon. (author)

  15. Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

    International Nuclear Information System (INIS)

    Shuleiko, D V; Ilin, A S

    2016-01-01

    Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa 93 /Si 3 N 4 and SiN 0 . 8 /Si 3 N 4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals. (paper)

  16. Advances in silicon nanophotonics

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Pu, Minhao

    Silicon has long been established as an ideal material for passive integrated optical circuitry due to its high refractive index, with corresponding strong optical confinement ability, and its low-cost CMOS-compatible manufacturability. However, the inversion symmetry of the silicon crystal lattice.......g. in high-bit-rate optical communication circuits and networks, it is vital that the nonlinear optical effects of silicon are being strongly enhanced. This can among others be achieved in photonic-crystal slow-light waveguides and in nano-engineered photonic-wires (Fig. 1). In this talk I shall present some...... recent advances in this direction. The efficient coupling of light between optical fibers and the planar silicon devices and circuits is of crucial importance. Both end-coupling (Fig. 1) and grating-coupling solutions will be discussed along with polarization issues. A new scheme for a hybrid III...

  17. Integrated silicon optoelectronics

    CERN Document Server

    Zimmermann, Horst

    2000-01-01

    'Integrated Silicon Optoelectronics'assembles optoelectronics and microelectronics The book concentrates on silicon as the major basis of modern semiconductor devices and circuits Starting from the basics of optical emission and absorption and from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included The book, furthermore, contains a review of the state of research on eagerly expected silicon light emitters In order to cover the topic of the book comprehensively, integrated waveguides, gratings, and optoelectronic power devices are included in addition Numerous elaborate illustrations promote an easy comprehension 'Integrated Silicon Optoelectronics'will be of value to engineers, physicists, and scientists in industry and at universities The book is also recommendable for graduate students speciali...

  18. Silicon microfabricated beam expander

    International Nuclear Information System (INIS)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-01-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed

  19. Silicon microfabricated beam expander

    Science.gov (United States)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  20. Silicon microfabricated beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A., E-mail: aliman@ppinang.uitm.edu.my; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A. [Faculty of Electrical Engineering, Universiti Teknologi MARA Malaysia, 40450, Shah Alam, Selangor (Malaysia); Ain, M. F. [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300,Nibong Tebal, Pulau Pinang (Malaysia)

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  1. Porous Silicon Nanowires

    Science.gov (United States)

    Qu, Yongquan; Zhou, Hailong; Duan, Xiangfeng

    2011-01-01

    In this minreview, we summarize recent progress in the synthesis, properties and applications of a new type of one-dimensional nanostructures — single crystalline porous silicon nanowires. The growth of porous silicon nanowires starting from both p- and n-type Si wafers with a variety of dopant concentrations can be achieved through either one-step or two-step reactions. The mechanistic studies indicate the dopant concentration of Si wafers, oxidizer concentration, etching time and temperature can affect the morphology of the as-etched silicon nanowires. The porous silicon nanowires are both optically and electronically active and have been explored for potential applications in diverse areas including photocatalysis, lithium ion battery, gas sensor and drug delivery. PMID:21869999

  2. Nanostructured silicon for thermoelectric

    Science.gov (United States)

    Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

    2011-06-01

    Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3ω method will be shown.

  3. Study on Silicon detectors

    International Nuclear Information System (INIS)

    Gervino, G.; Boero, M.; Manfredotti, C.; Icardi, M.; Gabutti, A.; Bagnolatti, E.; Monticone, E.

    1990-01-01

    Prototypes of Silicon microstrip detectors and Silicon large area detectors (3x2 cm 2 ), realized directly by our group, either by ion implantation or by diffusion are presented. The physical detector characteristics and their performances determined by exposing them to different radioactive sources and the results of extensive tests on passivation, where new technological ways have been investigated, are discussed. The calculation of the different terms contributing to the total dark current is reported

  4. Does a pear growl? Interference from semantic properties of orthographic neighbors.

    Science.gov (United States)

    Pecher, Diane; de Rooij, Jimmy; Zeelenberg, René

    2009-07-01

    In this study, we investigated whether semantic properties of a word's orthographic neighbors are activated during visual word recognition. In two experiments, words were presented with a property that was not true for the word itself. We manipulated whether the property was true for an orthographic neighbor of the word. Our results showed that rejection of the property was slower and less accurate when the property was true for a neighbor than when the property was not true for a neighbor. These findings indicate that semantic information is activated before orthographic processing is finished. The present results are problematic for the links model (Forster, 2006; Forster & Hector, 2002) that was recently proposed in order to bring form-first models of visual word recognition into line with previously reported findings (Forster & Hector, 2002; Pecher, Zeelenberg, & Wagenmakers, 2005; Rodd, 2004).

  5. Nearest neighbors EPR superhyperfine interaction in divalent iridium complexes in alkali halide host lattice

    International Nuclear Information System (INIS)

    Pinhal, N.M.; Vugman, N.V.

    1983-01-01

    Further splitting of chlorine superhyperfine lines on the EPR spectrum of the [Ir (CN) 4 Cl 2 ] 4 - molecular species in NaCl latice indicates a super-superhyperfine interaction with the nearest neighbors sodium atoms. (Author) [pt

  6. The influence of neighbors' family size preference on progression to high parity births in rural Nepal.

    Science.gov (United States)

    Jennings, Elyse A; Barber, Jennifer S

    2013-03-01

    Large families can have a negative impact on the health and well-being of women, children, and their communities. Seventy-three percent of the individuals in our rural Nepalese sample report that two children is their ideal number, yet about half of the married women continue childbearing after their second child. Using longitudinal data from the Chitwan Valley Family Study, we explore the influence of women's and neighbors' family size preferences on women's progression to high parity births, comparing this influence across two cohorts. We find that neighbors' family size preferences influence women's fertility, that older cohorts of women are more influenced by their neighbors' preferences than are younger cohorts of women, and that the influence of neighbors' preferences is independent of women's own preferences. © 2013 The Population Council, Inc.

  7. On Competitiveness of Nearest-Neighbor-Based Music Classification: A Methodological Critique

    DEFF Research Database (Denmark)

    Pálmason, Haukur; Jónsson, Björn Thór; Amsaleg, Laurent

    2017-01-01

    The traditional role of nearest-neighbor classification in music classification research is that of a straw man opponent for the learning approach of the hour. Recent work in high-dimensional indexing has shown that approximate nearest-neighbor algorithms are extremely scalable, yielding results...... of reasonable quality from billions of high-dimensional features. With such efficient large-scale classifiers, the traditional music classification methodology of aggregating and compressing the audio features is incorrect; instead the approximate nearest-neighbor classifier should be given an extensive data...... collection to work with. We present a case study, using a well-known MIR classification benchmark with well-known music features, which shows that a simple nearest-neighbor classifier performs very competitively when given ample data. In this position paper, we therefore argue that nearest...

  8. Efficient and accurate nearest neighbor and closest pair search in high-dimensional space

    KAUST Repository

    Tao, Yufei; Yi, Ke; Sheng, Cheng; Kalnis, Panos

    2010-01-01

    Nearest Neighbor (NN) search in high-dimensional space is an important problem in many applications. From the database perspective, a good solution needs to have two properties: (i) it can be easily incorporated in a relational database, and (ii

  9. Mixed random walks with a trap in scale-free networks including nearest-neighbor and next-nearest-neighbor jumps

    Science.gov (United States)

    Zhang, Zhongzhi; Dong, Yuze; Sheng, Yibin

    2015-10-01

    Random walks including non-nearest-neighbor jumps appear in many real situations such as the diffusion of adatoms and have found numerous applications including PageRank search algorithm; however, related theoretical results are much less for this dynamical process. In this paper, we present a study of mixed random walks in a family of fractal scale-free networks, where both nearest-neighbor and next-nearest-neighbor jumps are included. We focus on trapping problem in the network family, which is a particular case of random walks with a perfect trap fixed at the central high-degree node. We derive analytical expressions for the average trapping time (ATT), a quantitative indicator measuring the efficiency of the trapping process, by using two different methods, the results of which are consistent with each other. Furthermore, we analytically determine all the eigenvalues and their multiplicities for the fundamental matrix characterizing the dynamical process. Our results show that although next-nearest-neighbor jumps have no effect on the leading scaling of the trapping efficiency, they can strongly affect the prefactor of ATT, providing insight into better understanding of random-walk process in complex systems.

  10. Subwavelength silicon photonics

    International Nuclear Information System (INIS)

    Cheben, P.; Bock, P.J.; Schmid, J.H.; Lapointe, J.; Janz, S.; Xu, D.-X.; Densmore, A.; Delage, A.; Lamontagne, B.; Florjanczyk, M.; Ma, R.

    2011-01-01

    With the goal of developing photonic components that are compatible with silicon microelectronic integrated circuits, silicon photonics has been the subject of intense research activity. Silicon is an excellent material for confining and manipulating light at the submicrometer scale. Silicon optoelectronic integrated devices have the potential to be miniaturized and mass-produced at affordable cost for many applications, including telecommunications, optical interconnects, medical screening, and biological and chemical sensing. We review recent advances in silicon photonics research at the National Research Council Canada. A new type of optical waveguide is presented, exploiting subwavelength grating (SWG) effect. We demonstrate subwavelength grating waveguides made of silicon, including practical components operating at telecom wavelengths: input couplers, waveguide crossings and spectrometer chips. SWG technique avoids loss and wavelength resonances due to diffraction effects and allows for single-mode operation with direct control of the mode confinement by changing the refractive index of a waveguide core over a range as broad as 1.6 - 3.5 simply by lithographic patterning. The light can be launched to these waveguides with a coupling loss as small as 0.5 dB and with minimal wavelength dependence, using coupling structures similar to that shown in Fig. 1. The subwavelength grating waveguides can cross each other with minimal loss and negligible crosstalk which allows massive photonic circuit connectivity to overcome the limits of electrical interconnects. These results suggest that the SWG waveguides could become key elements for future integrated photonic circuits. (authors)

  11. Silicon microphotonic waveguides

    International Nuclear Information System (INIS)

    Ta'eed, V.; Steel, M.J.; Grillet, C.; Eggleton, B.; Du, J.; Glasscock, J.; Savvides, N.

    2004-01-01

    Full text: Silicon microphotonic devices have been drawing increasing attention in the past few years. The high index-difference between silicon and its oxide (Δn = 2) suggests a potential for high-density integration of optical functions on to a photonic chip. Additionally, it has been shown that silicon exhibits strong Raman nonlinearity, a necessary property as light interaction can occur only by means of nonlinearities in the propagation medium. The small dimensions of silicon waveguides require the design of efficient tapers to couple light to them. We have used the beam propagation method (RSoft BeamPROP) to understand the principles and design of an inverse-taper mode-converter as implemented in several recent papers. We report on progress in the design and fabrication of silicon-based waveguides. Preliminary work has been conducted by patterning silicon-on-insulator (SOI) wafers using optical lithography and reactive ion etching. Thus far, only rib waveguides have been designed, as single-mode ridge-waveguides are beyond the capabilities of conventional optical lithography. We have recently moved to electron beam lithography as the higher resolutions permitted will provide the flexibility to begin fabricating sub-micron waveguides

  12. Symmetric Link Key Management for Secure Neighbor Discovery in a Decentralized Wireless Sensor Network

    Science.gov (United States)

    2017-09-01

    KEY MANAGEMENT FOR SECURE NEIGHBOR DISCOVERY IN A DECENTRALIZED WIRELESS SENSOR NETWORK by Kelvin T. Chew September 2017 Thesis Advisor...and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington, DC 20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT...DATE September 2017 3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE SYMMETRIC LINK KEY MANAGEMENT FOR SECURE NEIGHBOR

  13. SibRank: Signed bipartite network analysis for neighbor-based collaborative ranking

    Science.gov (United States)

    Shams, Bita; Haratizadeh, Saman

    2016-09-01

    Collaborative ranking is an emerging field of recommender systems that utilizes users' preference data rather than rating values. Unfortunately, neighbor-based collaborative ranking has gained little attention despite its more flexibility and justifiability. This paper proposes a novel framework, called SibRank that seeks to improve the state of the art neighbor-based collaborative ranking methods. SibRank represents users' preferences as a signed bipartite network, and finds similar users, through a novel personalized ranking algorithm in signed networks.

  14. The impact of vacant, tax-delinquent, and foreclosed property on sales prices of neighboring homes

    OpenAIRE

    Stephan Whitaker; Thomas J. Fitzpatrick

    2012-01-01

    In this empirical analysis, we estimate the impact of vacancy, neglect associated with property-tax delinquency, and foreclosures on the value of neighboring homes using parcel-level observations. Numerous studies have estimated the impact of foreclosures on neighboring properties, and these papers theorize that the foreclosure impact works partially through creating vacant and neglected homes. To our knowledge, this is only the second attempt to estimate the impact of vacancy itself and the ...

  15. The Patient-Centered Medical Home Neighbor: A Critical Concept for a Redesigned Healthcare Delivery System

    Science.gov (United States)

    2011-01-25

    Sharing Knowledge: Achieving Breakthrough Performance 2010 Military Health System Conference The Patient -Centered Medical Home Neighbor: A Critical...DATE 25 JAN 2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE The Patient -Centered Medical Home Neighbor: A...Conference What is the Patient -Centered Medical Home?  …a vision of health care as it should be  …a framework for organizing systems of care at both the

  16. High-performance RF coil inductors on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Malba, V.; Young, D.; Ou, J.J.; Bernhardt, A.F.; Boser, B.E.

    1998-03-01

    Strong demand for wireless communication devices has motivated research directed toward monolithic integration of transceivers. The fundamental electronic component least compatible with silicon integrated circuits is the inductor, although a number of inductors are required to implement oscillators, filters and matching networks in cellular devices. Spiral inductors have been integrated into the silicon IC metallization sequence but have not performed adequately due to coupling to the silicon which results in parasitic capacitance and loss. We have, for the first time, fabricated three dimensional coil inductors on silicon which have significantly lower capacitive coupling and loss and which now exceed the requirements of potential applications. Quality factors of 30 at 1 GHz have been measured in single turn devices and Q > 16 in 2 and 4 turn devices. The reduced Q for multiturn devices appears to be related to eddy currents in outer turns generated by magnetic fields from current in neighboring turns. Higher Q values significantly in excess of 30 are anticipated using modified coil designs.

  17. Amorphous silicon crystalline silicon heterojunction solar cells

    CERN Document Server

    Fahrner, Wolfgang Rainer

    2013-01-01

    Amorphous Silicon/Crystalline Silicon Solar Cells deals with some typical properties of heterojunction solar cells, such as their history, the properties and the challenges of the cells, some important measurement tools, some simulation programs and a brief survey of the state of the art, aiming to provide an initial framework in this field and serve as a ready reference for all those interested in the subject. This book helps to "fill in the blanks" on heterojunction solar cells. Readers will receive a comprehensive overview of the principles, structures, processing techniques and the current developmental states of the devices. Prof. Dr. Wolfgang R. Fahrner is a professor at the University of Hagen, Germany and Nanchang University, China.

  18. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlö gl, Udo

    2015-01-01

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  19. Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

    Science.gov (United States)

    Whitman, Pamela K.; Feke, Donald L.

    1986-01-01

    The effects of various powder treatment strategies on the colloid chemistry of aqueous dispersions of silicon carbide and silicon nitride are examined using a surface titration methodology. Pretreatments are used to differentiate between the true surface chemistry of the powders and artifacts resulting from exposure history. Silicon nitride powders require more extensive pretreatment to reveal consistent surface chemistry than do silicon carbide powders. As measured by titration, the degree of proton adsorption from the suspending fluid by pretreated silicon nitride and silicon carbide powders can both be made similar to that of silica.

  20. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.

    2015-06-18

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  1. Co-Expression of Neighboring Genes in the Zebrafish (Danio rerio Genome

    Directory of Open Access Journals (Sweden)

    Daryi Wang

    2009-08-01

    Full Text Available Neighboring genes in the eukaryotic genome have a tendency to express concurrently, and the proximity of two adjacent genes is often considered a possible explanation for their co-expression behavior. However, the actual contribution of the physical distance between two genes to their co-expression behavior has yet to be defined. To further investigate this issue, we studied the co-expression of neighboring genes in zebrafish, which has a compact genome and has experienced a whole genome duplication event. Our analysis shows that the proportion of highly co-expressed neighboring pairs (Pearson’s correlation coefficient R>0.7 is low (0.24% ~ 0.67%; however, it is still significantly higher than that of random pairs. In particular, the statistical result implies that the co-expression tendency of neighboring pairs is negatively correlated with their physical distance. Our findings therefore suggest that physical distance may play an important role in the co-expression of neighboring genes. Possible mechanisms related to the neighboring genes’ co-expression are also discussed.

  2. Finger vein identification using fuzzy-based k-nearest centroid neighbor classifier

    Science.gov (United States)

    Rosdi, Bakhtiar Affendi; Jaafar, Haryati; Ramli, Dzati Athiar

    2015-02-01

    In this paper, a new approach for personal identification using finger vein image is presented. Finger vein is an emerging type of biometrics that attracts attention of researchers in biometrics area. As compared to other biometric traits such as face, fingerprint and iris, finger vein is more secured and hard to counterfeit since the features are inside the human body. So far, most of the researchers focus on how to extract robust features from the captured vein images. Not much research was conducted on the classification of the extracted features. In this paper, a new classifier called fuzzy-based k-nearest centroid neighbor (FkNCN) is applied to classify the finger vein image. The proposed FkNCN employs a surrounding rule to obtain the k-nearest centroid neighbors based on the spatial distributions of the training images and their distance to the test image. Then, the fuzzy membership function is utilized to assign the test image to the class which is frequently represented by the k-nearest centroid neighbors. Experimental evaluation using our own database which was collected from 492 fingers shows that the proposed FkNCN has better performance than the k-nearest neighbor, k-nearest-centroid neighbor and fuzzy-based-k-nearest neighbor classifiers. This shows that the proposed classifier is able to identify the finger vein image effectively.

  3. Plant neighbor identity influences plant biochemistry and physiology related to defense.

    Science.gov (United States)

    Broz, Amanda K; Broeckling, Corey D; De-la-Peña, Clelia; Lewis, Matthew R; Greene, Erick; Callaway, Ragan M; Sumner, Lloyd W; Vivanco, Jorge M

    2010-06-17

    Chemical and biological processes dictate an individual organism's ability to recognize and respond to other organisms. A small but growing body of evidence suggests that plants may be capable of recognizing and responding to neighboring plants in a species specific fashion. Here we tested whether or not individuals of the invasive exotic weed, Centaurea maculosa, would modulate their defensive strategy in response to different plant neighbors. In the greenhouse, C. maculosa individuals were paired with either conspecific (C. maculosa) or heterospecific (Festuca idahoensis) plant neighbors and elicited with the plant defense signaling molecule methyl jasmonate to mimic insect herbivory. We found that elicited C. maculosa plants grown with conspecific neighbors exhibited increased levels of total phenolics, whereas those grown with heterospecific neighbors allocated more resources towards growth. To further investigate these results in the field, we conducted a metabolomics analysis to explore chemical differences between individuals of C. maculosa growing in naturally occurring conspecific and heterospecific field stands. Similar to the greenhouse results, C. maculosa individuals accumulated higher levels of defense-related secondary metabolites and lower levels of primary metabolites when growing in conspecific versus heterospecific field stands. Leaf herbivory was similar in both stand types; however, a separate field study positively correlated specialist herbivore load with higher densities of C. maculosa conspecifics. Our results suggest that an individual C. maculosa plant can change its defensive strategy based on the identity of its plant neighbors. This is likely to have important consequences for individual and community success.

  4. Plant neighbor identity influences plant biochemistry and physiology related to defense

    Directory of Open Access Journals (Sweden)

    Callaway Ragan M

    2010-06-01

    Full Text Available Abstract Background Chemical and biological processes dictate an individual organism's ability to recognize and respond to other organisms. A small but growing body of evidence suggests that plants may be capable of recognizing and responding to neighboring plants in a species specific fashion. Here we tested whether or not individuals of the invasive exotic weed, Centaurea maculosa, would modulate their defensive strategy in response to different plant neighbors. Results In the greenhouse, C. maculosa individuals were paired with either conspecific (C. maculosa or heterospecific (Festuca idahoensis plant neighbors and elicited with the plant defense signaling molecule methyl jasmonate to mimic insect herbivory. We found that elicited C. maculosa plants grown with conspecific neighbors exhibited increased levels of total phenolics, whereas those grown with heterospecific neighbors allocated more resources towards growth. To further investigate these results in the field, we conducted a metabolomics analysis to explore chemical differences between individuals of C. maculosa growing in naturally occurring conspecific and heterospecific field stands. Similar to the greenhouse results, C. maculosa individuals accumulated higher levels of defense-related secondary metabolites and lower levels of primary metabolites when growing in conspecific versus heterospecific field stands. Leaf herbivory was similar in both stand types; however, a separate field study positively correlated specialist herbivore load with higher densities of C. maculosa conspecifics. Conclusions Our results suggest that an individual C. maculosa plant can change its defensive strategy based on the identity of its plant neighbors. This is likely to have important consequences for individual and community success.

  5. Pollinator-mediated interactions in experimental arrays vary with neighbor identity.

    Science.gov (United States)

    Ha, Melissa K; Ivey, Christopher T

    2017-02-01

    Local ecological conditions influence the impact of species interactions on evolution and community structure. We investigated whether pollinator-mediated interactions between coflowering plants vary with plant density, coflowering neighbor identity, and flowering season. We conducted a field experiment in which flowering time and floral neighborhood were manipulated in a factorial design. Early- and late-flowering Clarkia unguiculata plants were placed into arrays with C. biloba neighbors, noncongeneric neighbors, additional conspecific plants, or no additional plants as a density control. We compared whole-plant pollen limitation of seed set, pollinator behavior, and pollen deposition among treatments. Interactions mediated by shared pollinators depended on the identity of the neighbor and possibly changed through time, although flowering-season comparisons were compromised by low early-season plant survival. Interactions with conspecific neighbors were likely competitive late in the season. Interactions with C. biloba appeared to involve facilitation or neutral interactions. Interactions with noncongeners were more consistently competitive. The community composition of pollinators varied among treatment combinations. Pollinator-mediated interactions involved competition and likely facilitation, depending on coflowering neighbor. Experimental manipulation helped to reveal context-dependent variation in indirect biotic interactions. © 2017 Botanical Society of America.

  6. Spiral silicon drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

    1988-01-01

    An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs

  7. Performance improvement of silicon solar cells by nanoporous silicon coating

    Directory of Open Access Journals (Sweden)

    Dzhafarov T. D.

    2012-04-01

    Full Text Available In the present paper the method is shown to improve the photovoltaic parameters of screen-printed silicon solar cells by nanoporous silicon film formation on the frontal surface of the cell using the electrochemical etching. The possible mechanisms responsible for observed improvement of silicon solar cell performance are discussed.

  8. Neuromorphic Silicon Neuron Circuits

    Science.gov (United States)

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Hamilton, Tara Julia; van Schaik, André; Etienne-Cummings, Ralph; Delbruck, Tobi; Liu, Shih-Chii; Dudek, Piotr; Häfliger, Philipp; Renaud, Sylvie; Schemmel, Johannes; Cauwenberghs, Gert; Arthur, John; Hynna, Kai; Folowosele, Fopefolu; Saighi, Sylvain; Serrano-Gotarredona, Teresa; Wijekoon, Jayawan; Wang, Yingxue; Boahen, Kwabena

    2011-01-01

    Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain–machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance-based Hodgkin–Huxley models to bi-dimensional generalized adaptive integrate and fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips. PMID:21747754

  9. Silicon containing copolymers

    CERN Document Server

    Amiri, Sahar; Amiri, Sanam

    2014-01-01

    Silicones have unique properties including thermal oxidative stability, low temperature flow, high compressibility, low surface tension, hydrophobicity and electric properties. These special properties have encouraged the exploration of alternative synthetic routes of well defined controlled microstructures of silicone copolymers, the subject of this Springer Brief. The authors explore the synthesis and characterization of notable block copolymers. Recent advances in controlled radical polymerization techniques leading to the facile synthesis of well-defined silicon based thermo reversible block copolymers?are described along with atom transfer radical polymerization (ATRP), a technique utilized to develop well-defined functional thermo reversible block copolymers. The brief also focuses on Polyrotaxanes and their great potential as stimulus-responsive materials which produce poly (dimethyl siloxane) (PDMS) based thermo reversible block copolymers.

  10. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    Giacomo eIndiveri

    2011-05-01

    Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

  11. Floating Silicon Method

    Energy Technology Data Exchange (ETDEWEB)

    Kellerman, Peter

    2013-12-21

    The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

  12. The LHCb Silicon Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, Mark, E-mail: Mark.Tobin@epfl.ch

    2016-09-21

    The LHCb experiment is dedicated to the study of heavy flavour physics at the Large Hadron Collider (LHC). The primary goal of the experiment is to search for indirect evidence of new physics via measurements of CP violation and rare decays of beauty and charm hadrons. The LHCb detector has a large-area silicon micro-strip detector located upstream of a dipole magnet, and three tracking stations with silicon micro-strip detectors in the innermost region downstream of the magnet. These two sub-detectors form the LHCb Silicon Tracker (ST). This paper gives an overview of the performance and operation of the ST during LHC Run 1. Measurements of the observed radiation damage are shown and compared to the expectation from simulation.

  13. Removal of inclusions from silicon

    Science.gov (United States)

    Ciftja, Arjan; Engh, Thorvald Abel; Tangstad, Merete; Kvithyld, Anne; Øvrelid, Eivind Johannes

    2009-11-01

    The removal of inclusions from molten silicon is necessary to satisfy the purity requirements for solar grade silicon. This paper summarizes two methods that are investigated: (i) settling of the inclusions followed by subsequent directional solidification and (infiltration by ceramic foam filters. Settling of inclusions followed by directional solidification is of industrial importance for production of low-cost solar grade silicon. Filtration is reported as the most efficient method for removal of inclusions from the top-cut silicon scrap.

  14. Silicon photonic integration in telecommunications

    Directory of Open Access Journals (Sweden)

    Christopher Richard Doerr

    2015-08-01

    Full Text Available Silicon photonics is the guiding of light in a planar arrangement of silicon-based materials to perform various functions. We focus here on the use of silicon photonics to create transmitters and receivers for fiber-optic telecommunications. As the need to squeeze more transmission into a given bandwidth, a given footprint, and a given cost increases, silicon photonics makes more and more economic sense.

  15. Silicon Tracking Upgrade at CDF

    International Nuclear Information System (INIS)

    Kruse, M.C.

    1998-04-01

    The Collider Detector at Fermilab (CDF) is scheduled to begin recording data from Run II of the Fermilab Tevatron in early 2000. The silicon tracking upgrade constitutes both the upgrade to the CDF silicon vertex detector (SVX II) and the new Intermediate Silicon Layers (ISL) located at radii just beyond the SVX II. Here we review the design and prototyping of all aspects of these detectors including mechanical design, data acquisition, and a trigger based on silicon tracking

  16. Silicon microphones - a Danish perspective

    DEFF Research Database (Denmark)

    Bouwstra, Siebe; Storgaard-Larsen, Torben; Scheeper, Patrick

    1998-01-01

    Two application areas of microphones are discussed, those for precision measurement and those for hearing instruments. Silicon microphones are under investigation for both areas, and Danish industry plays a key role in both. The opportunities of silicon, as well as the challenges and expectations......, are discussed. For precision measurement the challenge for silicon is large, while for hearing instruments silicon seems to be very promising....

  17. Handling Neighbor Discovery and Rendezvous Consistency with Weighted Quorum-Based Approach.

    Science.gov (United States)

    Own, Chung-Ming; Meng, Zhaopeng; Liu, Kehan

    2015-09-03

    Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs) and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS), which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system.

  18. Handling Neighbor Discovery and Rendezvous Consistency with Weighted Quorum-Based Approach

    Directory of Open Access Journals (Sweden)

    Chung-Ming Own

    2015-09-01

    Full Text Available Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS, which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system.

  19. Plant Clonal Integration Mediates the Horizontal Redistribution of Soil Resources, Benefiting Neighboring Plants.

    Science.gov (United States)

    Ye, Xue-Hua; Zhang, Ya-Lin; Liu, Zhi-Lan; Gao, Shu-Qin; Song, Yao-Bin; Liu, Feng-Hong; Dong, Ming

    2016-01-01

    Resources such as water taken up by plants can be released into soils through hydraulic redistribution and can also be translocated by clonal integration within a plant clonal network. We hypothesized that the resources from one (donor) microsite could be translocated within a clonal network, released into different (recipient) microsites and subsequently used by neighbor plants in the recipient microsite. To test these hypotheses, we conducted two experiments in which connected and disconnected ramet pairs of Potentilla anserina were grown under both homogeneous and heterogeneous water regimes, with seedlings of Artemisia ordosica as neighbors. The isotopes [(15)N] and deuterium were used to trace the translocation of nitrogen and water, respectively, within the clonal network. The water and nitrogen taken up by P. anserina ramets in the donor microsite were translocated into the connected ramets in the recipient microsites. Most notably, portions of the translocated water and nitrogen were released into the recipient microsite and were used by the neighboring A. ordosica, which increased growth of the neighboring A. ordosica significantly. Therefore, our hypotheses were supported, and plant clonal integration mediated the horizontal hydraulic redistribution of resources, thus benefiting neighboring plants. Such a plant clonal integration-mediated resource redistribution in horizontal space may have substantial effects on the interspecific relations and composition of the community and consequently on ecosystem processes.

  20. Error Analysis for RADAR Neighbor Matching Localization in Linear Logarithmic Strength Varying Wi-Fi Environment

    Directory of Open Access Journals (Sweden)

    Mu Zhou

    2014-01-01

    Full Text Available This paper studies the statistical errors for the fingerprint-based RADAR neighbor matching localization with the linearly calibrated reference points (RPs in logarithmic received signal strength (RSS varying Wi-Fi environment. To the best of our knowledge, little comprehensive analysis work has appeared on the error performance of neighbor matching localization with respect to the deployment of RPs. However, in order to achieve the efficient and reliable location-based services (LBSs as well as the ubiquitous context-awareness in Wi-Fi environment, much attention has to be paid to the highly accurate and cost-efficient localization systems. To this end, the statistical errors by the widely used neighbor matching localization are significantly discussed in this paper to examine the inherent mathematical relations between the localization errors and the locations of RPs by using a basic linear logarithmic strength varying model. Furthermore, based on the mathematical demonstrations and some testing results, the closed-form solutions to the statistical errors by RADAR neighbor matching localization can be an effective tool to explore alternative deployment of fingerprint-based neighbor matching localization systems in the future.

  1. Error Analysis for RADAR Neighbor Matching Localization in Linear Logarithmic Strength Varying Wi-Fi Environment

    Science.gov (United States)

    Tian, Zengshan; Xu, Kunjie; Yu, Xiang

    2014-01-01

    This paper studies the statistical errors for the fingerprint-based RADAR neighbor matching localization with the linearly calibrated reference points (RPs) in logarithmic received signal strength (RSS) varying Wi-Fi environment. To the best of our knowledge, little comprehensive analysis work has appeared on the error performance of neighbor matching localization with respect to the deployment of RPs. However, in order to achieve the efficient and reliable location-based services (LBSs) as well as the ubiquitous context-awareness in Wi-Fi environment, much attention has to be paid to the highly accurate and cost-efficient localization systems. To this end, the statistical errors by the widely used neighbor matching localization are significantly discussed in this paper to examine the inherent mathematical relations between the localization errors and the locations of RPs by using a basic linear logarithmic strength varying model. Furthermore, based on the mathematical demonstrations and some testing results, the closed-form solutions to the statistical errors by RADAR neighbor matching localization can be an effective tool to explore alternative deployment of fingerprint-based neighbor matching localization systems in the future. PMID:24683349

  2. Improving Fraudster Detection in Online Auctions by Using Neighbor-Driven Attributes

    Directory of Open Access Journals (Sweden)

    Jun-Lin Lin

    2015-12-01

    Full Text Available Online auction websites use a simple reputation system to help their users to evaluate the trustworthiness of sellers and buyers. However, to improve their reputation in the reputation system, fraudulent users can easily deceive the reputation system by creating fake transactions. This inflated-reputation fraud poses a major problem for online auction websites because it can lead legitimate users into scams. Numerous approaches have been proposed in the literature to address this problem, most of which involve using social network analysis (SNA to derive critical features (e.g., k-core, center weight, and neighbor diversity for distinguishing fraudsters from legitimate users. This paper discusses the limitations of these SNA features and proposes a class of SNA features referred to as neighbor-driven attributes (NDAs. The NDAs of users are calculated from the features of their neighbors. Because fraudsters require collusive neighbors to provide them with positive ratings in the reputation system, using NDAs can be helpful for detecting fraudsters. Although the idea of NDAs is not entirely new, experimental results on a real-world dataset showed that using NDAs improves classification accuracy compared with state-of-the-art methods that use the k-core, center weight, and neighbor diversity.

  3. Velocity correlations and spatial dependencies between neighbors in a unidirectional flow of pedestrians

    Science.gov (United States)

    Porzycki, Jakub; WÄ s, Jarosław; Hedayatifar, Leila; Hassanibesheli, Forough; Kułakowski, Krzysztof

    2017-08-01

    The aim of the paper is an analysis of self-organization patterns observed in the unidirectional flow of pedestrians. On the basis of experimental data from Zhang et al. [J. Zhang et al., J. Stat. Mech. (2011) P06004, 10.1088/1742-5468/2011/06/P06004], we analyze the mutual positions and velocity correlations between pedestrians when walking along a corridor. The angular and spatial dependencies of the mutual positions reveal a spatial structure that remains stable during the crowd motion. This structure differs depending on the value of n , for the consecutive n th -nearest-neighbor position set. The preferred position for the first-nearest neighbor is on the side of the pedestrian, while for further neighbors, this preference shifts to the axis of movement. The velocity correlations vary with the angle formed by the pair of neighboring pedestrians and the direction of motion and with the time delay between pedestrians' movements. The delay dependence of the correlations shows characteristic oscillations, produced by the velocity oscillations when striding; however, a filtering of the main frequency of individual striding out reduces the oscillations only partially. We conclude that pedestrians select their path directions so as to evade the necessity of continuously adjusting their speed to their neighbors'. They try to keep a given distance, but follow the person in front of them, as well as accepting and observing pedestrians on their sides. Additionally, we show an empirical example that illustrates the shape of a pedestrian's personal space during movement.

  4. In situ influence of coal ash dump on the quality of neighboring surface and ground waters by applying correlation statistic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jasna M. Djinovic; Aleksandar R. Popovic [University of Belgrade, Belgrade (Serbia and Montenegro). Center of Chemistry, Institute of Chemistry, Technology and Metallurgy

    2007-01-15

    The aim of this study was to establish the real in situ influence of coal ash and slag transport and storage on the quality of neighboring surface and ground waters by applying correlation statistic analysis. It was found that the waste waters from the coal ash dump do not have any influence on the quality of the Danube river water. The Danube and the waste waters, however, influence the quality of the ground waters of the Petka spring. Changes in the concentrations of elements in the Danube or in the waste waters can have immediate or delayed impact on the quality of the spring waters. The immediate impact has calcium, magnesium, zinc, copper, vanadium, cobalt from Danube; magnesium, vanadium from overflow and drainage waters; copper from drainage water. And the delayed impact has calcium, magnesium, vanadium and silicon from the Danube waters, cobalt from drainage waters, chromium and silicon from overflow waters and magnesium and vanadium from both overflow and drainage waters. 20 refs., 2 figs., 4 tabs.

  5. CMS silicon tracker developments

    International Nuclear Information System (INIS)

    Civinini, C.; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell'Orso, R.; Della Marina, R.D.R.; Dutta, S.; Eklund, C.; Feld, L.; Fiore, L.; Focardi, E.; French, M.; Freudenreich, K.; Frey, A.; Fuertjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B. Mc; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B.

    2002-01-01

    The CMS Silicon tracker consists of 70 m 2 of microstrip sensors which design will be finalized at the end of 1999 on the basis of systematic studies of device characteristics as function of the most important parameters. A fundamental constraint comes from the fact that the detector has to be operated in a very hostile radiation environment with full efficiency. We present an overview of the current results and prospects for converging on a final set of parameters for the silicon tracker sensors

  6. Silicon hybrid integration

    International Nuclear Information System (INIS)

    Li Xianyao; Yuan Taonu; Shao Shiqian; Shi Zujun; Wang Yi; Yu Yude; Yu Jinzhong

    2011-01-01

    Recently,much attention has concentrated on silicon based photonic integrated circuits (PICs), which provide a cost-effective solution for high speed, wide bandwidth optical interconnection and optical communication.To integrate III-V compounds and germanium semiconductors on silicon substrates,at present there are two kinds of manufacturing methods, i.e., heteroepitaxy and bonding. Low-temperature wafer bonding which can overcome the high growth temperature, lattice mismatch,and incompatibility of thermal expansion coefficients during heteroepitaxy, has offered the possibility for large-scale heterogeneous integration. In this paper, several commonly used bonding methods are reviewed, and the future trends of low temperature wafer bonding envisaged. (authors)

  7. Strained Silicon Photonics

    Directory of Open Access Journals (Sweden)

    Ralf B. Wehrspohn

    2012-05-01

    Full Text Available A review of recent progress in the field of strained silicon photonics is presented. The application of strain to waveguide and photonic crystal structures can be used to alter the linear and nonlinear optical properties of these devices. Here, methods for the fabrication of strained devices are summarized and recent examples of linear and nonlinear optical devices are discussed. Furthermore, the relation between strain and the enhancement of the second order nonlinear susceptibility is investigated, which may enable the construction of optically active photonic devices made of silicon.

  8. Elite silicon and solar power

    International Nuclear Information System (INIS)

    Yasamanov, N.A.

    2000-01-01

    The article is of popular character, the following issues being considered: conversion of solar energy into electric one, solar batteries in space and on the Earth, growing of silicon large-size crystals, source material problems relating to silicon monocrystals production, outlooks of solar silicon batteries production [ru

  9. What Will the Neighbors Think? Building Large-Scale Science Projects Around the World

    International Nuclear Information System (INIS)

    Jones, Craig; Mrotzek, Christian; Toge, Nobu; Sarno, Doug

    2007-01-01

    Public participation is an essential ingredient for turning the International Linear Collider into a reality. Wherever the proposed particle accelerator is sited in the world, its neighbors -- in any country -- will have something to say about hosting a 35-kilometer-long collider in their backyards. When it comes to building large-scale physics projects, almost every laboratory has a story to tell. Three case studies from Japan, Germany and the US will be presented to examine how community relations are handled in different parts of the world. How do particle physics laboratories interact with their local communities? How do neighbors react to building large-scale projects in each region? How can the lessons learned from past experiences help in building the next big project? These and other questions will be discussed to engage the audience in an active dialogue about how a large-scale project like the ILC can be a good neighbor.

  10. A Novel Preferential Diffusion Recommendation Algorithm Based on User’s Nearest Neighbors

    Directory of Open Access Journals (Sweden)

    Fuguo Zhang

    2017-01-01

    Full Text Available Recommender system is a very efficient way to deal with the problem of information overload for online users. In recent years, network based recommendation algorithms have demonstrated much better performance than the standard collaborative filtering methods. However, most of network based algorithms do not give a high enough weight to the influence of the target user’s nearest neighbors in the resource diffusion process, while a user or an object with high degree will obtain larger influence in the standard mass diffusion algorithm. In this paper, we propose a novel preferential diffusion recommendation algorithm considering the significance of the target user’s nearest neighbors and evaluate it in the three real-world data sets: MovieLens 100k, MovieLens 1M, and Epinions. Experiments results demonstrate that the novel preferential diffusion recommendation algorithm based on user’s nearest neighbors can significantly improve the recommendation accuracy and diversity.

  11. Electronic transport of molecular nanowires by considering of electron hopping energy between the second neighbors

    Directory of Open Access Journals (Sweden)

    H Rabani

    2015-07-01

    Full Text Available In this paper, we study the electronic conductance of molecular nanowires by considering the electron hopping between the first and second neighbors with the help Green’s function method at the tight-binding approach. We investigate three types of structures including linear uniform and periodic chains as well as poly(p-phenylene molecule which are embedded between two semi-infinite metallic leads. The results show that in the second neighbor approximation, the resonance, anti-resonance and Fano phenomena occur in the conductance spectra of these structures. Moreover, a new gap is observed at edge of the lead energy band wich its width depends on the value of the electron hopping energy between the second neighbors. In the systems including intrinsic gap, this hopping energy shifts the gap in the energy spectra.

  12. A multilevel-skin neighbor list algorithm for molecular dynamics simulation

    Science.gov (United States)

    Zhang, Chenglong; Zhao, Mingcan; Hou, Chaofeng; Ge, Wei

    2018-01-01

    Searching of the interaction pairs and organization of the interaction processes are important steps in molecular dynamics (MD) algorithms and are critical to the overall efficiency of the simulation. Neighbor lists are widely used for these steps, where thicker skin can reduce the frequency of list updating but is discounted by more computation in distance check for the particle pairs. In this paper, we propose a new neighbor-list-based algorithm with a precisely designed multilevel skin which can reduce unnecessary computation on inter-particle distances. The performance advantages over traditional methods are then analyzed against the main simulation parameters on Intel CPUs and MICs (many integrated cores), and are clearly demonstrated. The algorithm can be generalized for various discrete simulations using neighbor lists.

  13. Learn good from bad: Effects of good and bad neighbors in spatial prisoners' dilemma games

    Science.gov (United States)

    Lu, Peng

    2015-10-01

    Cooperation is vital for the human society and this study focuses on how to promote cooperation. In our stratification model, there exist three classes: two minorities are elites who are prone to cooperate and scoundrels who are born to defect; one majority is the class of common people. Agents of these three classes interact with each other on a square lattice. Commons' cooperation and its factors are investigated. Contradicting our common sense, it indicates that elites play a negative role while scoundrels play a positive one in promoting commons' cooperation. Besides, effects of good and bad neighbors vary with temptation. When the temptation is smaller the positive effect is able to overcome the negative effect, but the later prevails when the temptation is larger. It concludes that common people are more prone to cooperate in harsh environment with bad neighbors, and a better environment with good neighbors merely leads to laziness and free riding of commons.

  14. Neighbor-dependent Ramachandran probability distributions of amino acids developed from a hierarchical Dirichlet process model.

    Directory of Open Access Journals (Sweden)

    Daniel Ting

    2010-04-01

    Full Text Available Distributions of the backbone dihedral angles of proteins have been studied for over 40 years. While many statistical analyses have been presented, only a handful of probability densities are publicly available for use in structure validation and structure prediction methods. The available distributions differ in a number of important ways, which determine their usefulness for various purposes. These include: 1 input data size and criteria for structure inclusion (resolution, R-factor, etc.; 2 filtering of suspect conformations and outliers using B-factors or other features; 3 secondary structure of input data (e.g., whether helix and sheet are included; whether beta turns are included; 4 the method used for determining probability densities ranging from simple histograms to modern nonparametric density estimation; and 5 whether they include nearest neighbor effects on the distribution of conformations in different regions of the Ramachandran map. In this work, Ramachandran probability distributions are presented for residues in protein loops from a high-resolution data set with filtering based on calculated electron densities. Distributions for all 20 amino acids (with cis and trans proline treated separately have been determined, as well as 420 left-neighbor and 420 right-neighbor dependent distributions. The neighbor-independent and neighbor-dependent probability densities have been accurately estimated using Bayesian nonparametric statistical analysis based on the Dirichlet process. In particular, we used hierarchical Dirichlet process priors, which allow sharing of information between densities for a particular residue type and different neighbor residue types. The resulting distributions are tested in a loop modeling benchmark with the program Rosetta, and are shown to improve protein loop conformation prediction significantly. The distributions are available at http://dunbrack.fccc.edu/hdp.

  15. Selective formation of porous silicon

    Science.gov (United States)

    Fathauer, Robert W. (Inventor); Jones, Eric W. (Inventor)

    1993-01-01

    A pattern of porous silicon is produced in the surface of a silicon substrate by forming a pattern of crystal defects in said surface, preferably by applying an ion milling beam through openings in a photoresist layer to the surface, and then exposing said surface to a stain etchant, such as HF:HNO3:H2O. The defected crystal will preferentially etch to form a pattern of porous silicon. When the amorphous content of the porous silicon exceeds 70 percent, the porous silicon pattern emits visible light at room temperature.

  16. Transformational silicon electronics

    KAUST Repository

    Rojas, Jhonathan Prieto; Sevilla, Galo T.; Ghoneim, Mohamed T.; Inayat, Salman Bin; Ahmed, Sally; Hussain, Aftab M.; Hussain, Muhammad Mustafa

    2014-01-01

    In today's traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100

  17. Silicon nitride nanosieve membrane

    NARCIS (Netherlands)

    Tong, D.H.; Jansen, Henricus V.; Gadgil, V.J.; Bostan, C.G.; Berenschot, Johan W.; van Rijn, C.J.M.; Elwenspoek, Michael Curt

    2004-01-01

    An array of very uniform cylindrical nanopores with a pore diameter as small as 25 nm has been fabricated in an ultrathin micromachined silicon nitride membrane using focused ion beam (FIB) etching. The pore size of this nanosieve membrane was further reduced to below 10 nm by coating it with

  18. OPAL Silicon Tungsten Luminometer

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. The Silicon Tungsten Luminometer was part of OPAL's calorimeter which was used to measure the energy of particles. Most particles end their journey in calorimeters. These detectors measure the energy deposited when particles are slowed down and stopped.

  19. Silicon graphene Bragg gratings.

    Science.gov (United States)

    Capmany, José; Domenech, David; Muñoz, Pascual

    2014-03-10

    We propose the use of interleaved graphene sections on top of a silicon waveguide to implement tunable Bragg gratings. The filter central wavelength and bandwidth can be controlled changing the chemical potential of the graphene sections. Apodization techniques are also presented.

  20. On nanostructured silicon success

    DEFF Research Database (Denmark)

    Sigmund, Ole; Jensen, Jakob Søndergaard; Frandsen, Lars Hagedorn

    2016-01-01

    Recent Letters by Piggott et al. 1 and Shen et al. 2 claim the smallest ever dielectric wave length and polarization splitters. The associated News & Views article by Aydin3 states that these works “are the first experimental demonstration of on-chip, silicon photonic components based on complex...

  1. Silicon oxynitride based photonics

    NARCIS (Netherlands)

    Worhoff, Kerstin; Klein, E.J.; Hussein, M.G.; Driessen, A.; Marciniak, M.; Jaworski, M.; Zdanowicz, M.

    2008-01-01

    Silicon oxynitride is a very attractive material for integrated optics. Besides possessing excellent optical properties it can be deposited with refractive indices varying over a wide range by tuning the material composition. In this contribution we will summarize the key properties of this material

  2. ALICE Silicon Pixel Detector

    CERN Multimedia

    Manzari, V

    2013-01-01

    The Silicon Pixel Detector (SPD) forms the innermost two layers of the 6-layer barrel Inner Tracking System (ITS). The SPD plays a key role in the determination of the position of the primary collision and in the reconstruction of the secondary vertices from particle decays.

  3. ALICE Silicon Strip Detector

    CERN Multimedia

    Nooren, G

    2013-01-01

    The Silicon Strip Detector (SSD) constitutes the two outermost layers of the Inner Tracking System (ITS) of the ALICE Experiment. The SSD plays a crucial role in the tracking of the particles produced in the collisions connecting the tracks from the external detectors (Time Projection Chamber) to the ITS. The SSD also contributes to the particle identification through the measurement of their energy loss.

  4. DELPHI Silicon Tracker

    CERN Multimedia

    DELPHI was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. The silicon tracking detector was nearest to the collision point in the centre of the detector. It was used to pinpoint the collision and catch short-lived particles.

  5. Optimizing Neighbor Discovery for Ad hoc Networks based on the Bluetooth PAN Profile

    DEFF Research Database (Denmark)

    Kuijpers, Gerben; Nielsen, Thomas Toftegaard; Prasad, Ramjee

    2002-01-01

    IP layer neighbor discovery mechanisms rely highly on broadcast/multicast capabilities of the underlying link layer. The Bluetooth personal area network (PAN) profile has no native link layer broadcast/multicast capabilities and can only emulate this by repeatedly unicast link layer frames....... This paper introduces a neighbor discovery mechanism that utilizes the resources in the Bluetooth PAN profile more efficient. The performance of the new mechanism is investigated using a IPv6 network simulator and compared with emulated broadcasting. It is shown that the signaling overhead can...

  6. Long-term effect of September 11 on the political behavior of victims' families and neighbors.

    Science.gov (United States)

    Hersh, Eitan D

    2013-12-24

    This article investigates the long-term effect of September 11, 2001 on the political behaviors of victims' families and neighbors. Relative to comparable individuals, family members and residential neighbors of victims have become--and have stayed--significantly more active in politics in the last 12 years, and they have become more Republican on account of the terrorist attacks. The method used to demonstrate these findings leverages the random nature of the terrorist attack to estimate a causal effect and exploits new techniques to link multiple, individual-level, governmental databases to measure behavioral change without relying on surveys or aggregate analysis.

  7. Long-term effect of September 11 on the political behavior of victims’ families and neighbors

    Science.gov (United States)

    Hersh, Eitan D.

    2013-01-01

    This article investigates the long-term effect of September 11, 2001 on the political behaviors of victims’ families and neighbors. Relative to comparable individuals, family members and residential neighbors of victims have become—and have stayed—significantly more active in politics in the last 12 years, and they have become more Republican on account of the terrorist attacks. The method used to demonstrate these findings leverages the random nature of the terrorist attack to estimate a causal effect and exploits new techniques to link multiple, individual-level, governmental databases to measure behavioral change without relying on surveys or aggregate analysis. PMID:24324145

  8. Effect of Floquet engineering on the p-wave superconductor with second-neighbor couplings

    Science.gov (United States)

    Li, X. P.; Li, C. F.; Wang, L. C.; Zhou, L.

    2018-06-01

    The influence of the Floquet engineering on a particular one-dimensional p-wave superconductor, Kitaev model, with second-neighbor couplings is investigated in this paper. The effective Hamiltonians in the rotated reference frames have been obtained, and the convergent regions of the approximated Hamiltonian as well as the topological phase diagrams have been analyzed and discussed. We show that by modulating the external driving field amplitude, frequency as well as the second-neighbor hopping amplitude, the rich phase diagrams and transitions between different topological phases can be obtained.

  9. Arsenic implantation into polycrystalline silicon and diffusion to silicon substrate

    International Nuclear Information System (INIS)

    Tsukamoto, K.; Akasaka, Y.; Horie, K.

    1977-01-01

    Arsenic implantation into polycrystalline silicon and drive-in diffusion to silicon substrate have been investigated by MeV He + backscattering analysis and also by electrical measurements. The range distributions of arsenic implanted into polycrystalline silicon are well fitted to Gaussian distributions over the energy range 60--350 keV. The measured values of R/sub P/ and ΔR/sub P/ are about 10 and 20% larger than the theoretical predictions, respectively. The effective diffusion coefficient of arsenic implanted into polycrystalline silicon is expressed as D=0.63 exp[(-3.22 eV/kT)] and is independent of the arsenic concentration. The drive-in diffusion of arsenic from the implanted polycrystalline silicon layer into the silicon substrate is significantly affected by the diffusion atmosphere. In the N 2 atmosphere, a considerable amount of arsenic atoms diffuses outward to the ambient. The outdiffusion can be suppressed by encapsulation with Si 3 N 4 . In the oxidizing atmosphere, arsenic atoms are driven inward by growing SiO 2 due to the segregation between SiO 2 and polycrystalline silicon, and consequently the drive-in diffusion of arsenic is enhanced. At the interface between the polycrystalline silicon layer and the silicon substrate, arsenic atoms are likely to segregate at the polycrystalline silicon side

  10. Silicon epitaxy on textured double layer porous silicon by LPCVD

    International Nuclear Information System (INIS)

    Cai Hong; Shen Honglie; Zhang Lei; Huang Haibin; Lu Linfeng; Tang Zhengxia; Shen Jiancang

    2010-01-01

    Epitaxial silicon thin film on textured double layer porous silicon (DLPS) was demonstrated. The textured DLPS was formed by electrochemical etching using two different current densities on the silicon wafer that are randomly textured with upright pyramids. Silicon thin films were then grown on the annealed DLPS, using low-pressure chemical vapor deposition (LPCVD). The reflectance of the DLPS and the grown silicon thin films were studied by a spectrophotometer. The crystallinity and topography of the grown silicon thin films were studied by Raman spectroscopy and SEM. The reflectance results show that the reflectance of the silicon wafer decreases from 24.7% to 11.7% after texturing, and after the deposition of silicon thin film the surface reflectance is about 13.8%. SEM images show that the epitaxial silicon film on textured DLPS exhibits random pyramids. The Raman spectrum peaks near 521 cm -1 have a width of 7.8 cm -1 , which reveals the high crystalline quality of the silicon epitaxy.

  11. Silicon quantum processor with robust long-distance qubit couplings

    Energy Technology Data Exchange (ETDEWEB)

    Tosi, Guilherme; Mohiyaddin, Fahd A.; Schmitt, Vivien; Tenberg, Stefanie; Rahman, Rajib; Klimeck, Gerhard; Morello, Andrea

    2017-09-06

    Practical quantum computers require a large network of highly coherent qubits, interconnected in a design robust against errors. Donor spins in silicon provide state-of-the-art coherence and quantum gate fidelities, in a platform adapted from industrial semiconductor processing. Here we present a scalable design for a silicon quantum processor that does not require precise donor placement and leaves ample space for the routing of interconnects and readout devices. We introduce the flip-flop qubit, a combination of the electron-nuclear spin states of a phosphorus donor that can be controlled by microwave electric fields. Two-qubit gates exploit a second-order electric dipole-dipole interaction, allowing selective coupling beyond the nearest-neighbor, at separations of hundreds of nanometers, while microwave resonators can extend the entanglement to macroscopic distances. We predict gate fidelities within fault-tolerance thresholds using realistic noise models. This design provides a realizable blueprint for scalable spin-based quantum computers in silicon.

  12. The Influence of Neighbor Effect and Urbanization Toward Organ Donation in Thailand.

    Science.gov (United States)

    Wongboonsin, Kua; Jindahra, Pavitra; Teerakapibal, Surat

    2018-03-01

    Toward population wellness, an extreme scarcity of organ supply is proven to be an enormous hindrance. Preferences toward organ donation are vital to raise the organ donation rate. Notably, the area people live in can address the social influence on individual preference toward organ donation. This article studies the impact of the neighbor effect on organ donation decisions, addressing the social influence of urbanization on preferences. How neighborhood-specific variables, population density, and socioeconomic status drive the neighbor effect is investigated. The pursuit of organ donor traits is to be answered. The study uses organ donation interview survey data and neighborhood-specific data from Thailand to estimate a series of logistic regression models. Individuals residing in urban areas exhibit a greater likelihood to sign the donor card than those in rural areas. The neighborhood socioeconomic status is the key driver. An individual is more willing to be an organ donor when having neighbors with higher socioeconomic statuses. Results also reveal positive influences of males and education on the organ donation rate. This article documents the "neighbor effect" on the organ donation decision via living area type, offering an alternative exposition in raising the organ donation rate. In shifting the society norm toward organ donation consent, policy-makers should acknowledge the benefit of urbanization on organ donation decision derived from resourceful urban areas. Moreover, raising education levels does improve not only citizens' well-being but also their tendency to exhibit an altruistic act toward others.

  13. Applying an efficient K-nearest neighbor search to forest attribute imputation

    Science.gov (United States)

    Andrew O. Finley; Ronald E. McRoberts; Alan R. Ek

    2006-01-01

    This paper explores the utility of an efficient nearest neighbor (NN) search algorithm for applications in multi-source kNN forest attribute imputation. The search algorithm reduces the number of distance calculations between a given target vector and each reference vector, thereby, decreasing the time needed to discover the NN subset. Results of five trials show gains...

  14. Neighbor discovery in multi-hop wireless networks: evaluation and dimensioning with interferences considerations

    Directory of Open Access Journals (Sweden)

    Elyes Ben Hamida

    2008-04-01

    Full Text Available In this paper, we study the impact of collisions and interferences on a neighbor discovery process in the context of multi-hop wireless networks. We consider three models in which interferences and collisions are handled in very different ways. From an ideal channel where simultaneous transmissions do not interfere, we derive an alternate channel where simultaneous transmissions are considered two-by-two under the form of collisions, to finally reach a more realistic channel where simultaneous transmissions are handled under the form of shot-noise interferences. In these models, we analytically compute the link probability success between two neighbors as well as the expected number of nodes that correctly receive a Hello packet. Using this analysis, we show that if the neighbor discovery process is asymptotically equivalent in the three models, it offers very different behaviors locally in time. In particular, the scalability of the process is not the same depending on the way interferences are handled. Finally, we apply our results to the dimensioning of a Hello protocol parameters. We propose a method to adapt the protocol parameters to meet application constraints on the neighbor discovery process and to minimize the protocol energy consumption.

  15. Loving All Your Neighbors: Why Community Colleges Need the Academic Study of Religion

    Science.gov (United States)

    Maley, Melissa

    2013-01-01

    This chapter explains how the study of world religions prepares the community college student to become a better citizen, worker, and neighbor. The effective middle between the pitfalls of religious relativism and religious dominance in a world religions classroom is central to this discussion of teaching critical thinking, empathy, and…

  16. Stuttering Attitudes among Turkish Family Generations and Neighbors from Representative Samples

    Science.gov (United States)

    Ozdemir, R. Sertan; St. Louis, Kenneth O.; Topbas, Seyhun

    2011-01-01

    Purpose: Attitudes toward stuttering, measured by the "Public Opinion Survey of Human Attributes-Stuttering" ("POSHA-S"), are compared among (a) two different representative samples; (b) family generations (children, parents, and either grandparents or uncles and aunts) and neighbors; (c) children, parents, grandparents/adult…

  17. Estimating forest attribute parameters for small areas using nearest neighbors techniques

    Science.gov (United States)

    Ronald E. McRoberts

    2012-01-01

    Nearest neighbors techniques have become extremely popular, particularly for use with forest inventory data. With these techniques, a population unit prediction is calculated as a linear combination of observations for a selected number of population units in a sample that are most similar, or nearest, in a space of ancillary variables to the population unit requiring...

  18. Estimating cavity tree and snag abundance using negative binomial regression models and nearest neighbor imputation methods

    Science.gov (United States)

    Bianca N.I. Eskelson; Hailemariam Temesgen; Tara M. Barrett

    2009-01-01

    Cavity tree and snag abundance data are highly variable and contain many zero observations. We predict cavity tree and snag abundance from variables that are readily available from forest cover maps or remotely sensed data using negative binomial (NB), zero-inflated NB, and zero-altered NB (ZANB) regression models as well as nearest neighbor (NN) imputation methods....

  19. The indirect effects of cheatgrass invasion: Grasshopper herbivory on native grasses determined by neighboring cheatgrass abundance

    Science.gov (United States)

    Julie Beckstead; Susan E. Meyer; Carol K. Augsperger

    2008-01-01

    Invasion biology has focused on the direct effects of plant invasion and has generally overlooked indirect interactions. Here we link theories of invasion biology and herbivory to explore an indirect effect of one invading species on associational herbivory (the effect of neighboring plants on herbivory) of native species. We studied a Great Basin shadscale (...

  20. Mapping change of older forest with nearest-neighbor imputation and Landsat time-series

    Science.gov (United States)

    Janet L. Ohmann; Matthew J. Gregory; Heather M. Roberts; Warren B. Cohen; Robert E. Kennedy; Zhiqiang. Yang

    2012-01-01

    The Northwest Forest Plan (NWFP), which aims to conserve late-successional and old-growth forests (older forests) and associated species, established new policies on federal lands in the Pacific Northwest USA. As part of monitoring for the NWFP, we tested nearest-neighbor imputation for mapping change in older forest, defined by threshold values for forest attributes...

  1. Numerical Simulation of the Diffusion Processes in Nanoelectrode Arrays Using an Axial Neighbor Symmetry Approximation.

    Science.gov (United States)

    Peinetti, Ana Sol; Gilardoni, Rodrigo S; Mizrahi, Martín; Requejo, Felix G; González, Graciela A; Battaglini, Fernando

    2016-06-07

    Nanoelectrode arrays have introduced a complete new battery of devices with fascinating electrocatalytic, sensitivity, and selectivity properties. To understand and predict the electrochemical response of these arrays, a theoretical framework is needed. Cyclic voltammetry is a well-fitted experimental technique to understand the undergoing diffusion and kinetics processes. Previous works describing microelectrode arrays have exploited the interelectrode distance to simulate its behavior as the summation of individual electrodes. This approach becomes limited when the size of the electrodes decreases to the nanometer scale due to their strong radial effect with the consequent overlapping of the diffusional fields. In this work, we present a computational model able to simulate the electrochemical behavior of arrays working either as the summation of individual electrodes or being affected by the overlapping of the diffusional fields without previous considerations. Our computational model relays in dividing a regular electrode array in cells. In each of them, there is a central electrode surrounded by neighbor electrodes; these neighbor electrodes are transformed in a ring maintaining the same active electrode area than the summation of the closest neighbor electrodes. Using this axial neighbor symmetry approximation, the problem acquires a cylindrical symmetry, being applicable to any diffusion pattern. The model is validated against micro- and nanoelectrode arrays showing its ability to predict their behavior and therefore to be used as a designing tool.

  2. Impact of Training Bolivian Farmers on Integrated Pest Management and Diffusion of Knowledge to Neighboring Farmers

    DEFF Research Database (Denmark)

    Jørs, Erik; Konradsen, Flemming; Huici, Omar

    2016-01-01

    of importance to justify training costs and to promote a healthy and sustainable agriculture. Training on IPM of farmers took place from 2002 to 2004 in their villages in La Paz County, Bolivia, while dissemination of knowledge from trained farmer to neighboring farmer took place until 2009. To evaluate...

  3. Moderate-resolution data and gradient nearest neighbor imputation for regional-national risk assessment

    Science.gov (United States)

    Kenneth B. Jr. Pierce; C. Kenneth Brewer; Janet L. Ohmann

    2010-01-01

    This study was designed to test the feasibility of combining a method designed to populate pixels with inventory plot data at the 30-m scale with a new national predictor data set. The new national predictor data set was developed by the USDA Forest Service Remote Sensing Applications Center (hereafter RSAC) at the 250-m scale. Gradient Nearest Neighbor (GNN)...

  4. Integration and analysis of neighbor discovery and link quality estimation in wireless sensor networks.

    Science.gov (United States)

    Radi, Marjan; Dezfouli, Behnam; Abu Bakar, Kamalrulnizam; Abd Razak, Shukor

    2014-01-01

    Network connectivity and link quality information are the fundamental requirements of wireless sensor network protocols to perform their desired functionality. Most of the existing discovery protocols have only focused on the neighbor discovery problem, while a few number of them provide an integrated neighbor search and link estimation. As these protocols require a careful parameter adjustment before network deployment, they cannot provide scalable and accurate network initialization in large-scale dense wireless sensor networks with random topology. Furthermore, performance of these protocols has not entirely been evaluated yet. In this paper, we perform a comprehensive simulation study on the efficiency of employing adaptive protocols compared to the existing nonadaptive protocols for initializing sensor networks with random topology. In this regard, we propose adaptive network initialization protocols which integrate the initial neighbor discovery with link quality estimation process to initialize large-scale dense wireless sensor networks without requiring any parameter adjustment before network deployment. To the best of our knowledge, this work is the first attempt to provide a detailed simulation study on the performance of integrated neighbor discovery and link quality estimation protocols for initializing sensor networks. This study can help system designers to determine the most appropriate approach for different applications.

  5. 77 FR 50504 - Good Neighbor Environmental Board Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2012-08-21

    ... recommendations to the President and Congress on environmental and infrastructure issues along the U.S. border with Mexico. Purpose of Meeting: The purpose of this teleconference is to discuss the Good Neighbor Environmental Board's Fifteenth Report. The report will focus on water infrastructure issues in the U.S.-Mexico...

  6. 77 FR 13599 - Good Neighbor Environmental Board; Notification of Public Advisory Committee Teleconference

    Science.gov (United States)

    2012-03-07

    ... recommendations to the President and Congress on environmental and infrastructure issues along the U.S. border with Mexico. Purpose of Meeting: The purpose of this teleconference is to discuss the Good Neighbor Environmental Board's Fifteenth Report. The report will focus on water infrastructure issues in the U.S.-Mexico...

  7. Probability distributions for first neighbor distances between resonances that belong to two different families

    International Nuclear Information System (INIS)

    Difilippo, F.C.

    1994-01-01

    For a mixture of two families of resonances, we found the probability distribution for the distance, as first neighbors, between resonances that belong to different families. Integration of this distribution gives the probability of accidental overlapping of resonances of one isotope by resonances of the other, provided that the resonances of each isotope belong to a single family. (author)

  8. Neighbor Discovery Algorithm in Wireless Local Area Networks Using Multi-beam Directional Antennas

    Science.gov (United States)

    Wang, Jin; Peng, Wei; Liu, Song

    2017-10-01

    Neighbor discovery is an important step for Wireless Local Area Networks (WLAN) and the use of multi-beam directional antennas can greatly improve the network performance. However, most neighbor discovery algorithms in WLAN, based on multi-beam directional antennas, can only work effectively in synchronous system but not in asynchro-nous system. And collisions at AP remain a bottleneck for neighbor discovery. In this paper, we propose two asynchrono-us neighbor discovery algorithms: asynchronous hierarchical scanning (AHS) and asynchronous directional scanning (ADS) algorithm. Both of them are based on three-way handshaking mechanism. AHS and ADS reduce collisions at AP to have a good performance in a hierarchical way and directional way respectively. In the end, the performance of the AHS and ADS are tested on OMNeT++. Moreover, it is analyzed that different application scenarios and the factors how to affect the performance of these algorithms. The simulation results show that AHS is suitable for the densely populated scenes around AP while ADS is suitable for that most of the neighborhood nodes are far from AP.

  9. Integration and Analysis of Neighbor Discovery and Link Quality Estimation in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Marjan Radi

    2014-01-01

    Full Text Available Network connectivity and link quality information are the fundamental requirements of wireless sensor network protocols to perform their desired functionality. Most of the existing discovery protocols have only focused on the neighbor discovery problem, while a few number of them provide an integrated neighbor search and link estimation. As these protocols require a careful parameter adjustment before network deployment, they cannot provide scalable and accurate network initialization in large-scale dense wireless sensor networks with random topology. Furthermore, performance of these protocols has not entirely been evaluated yet. In this paper, we perform a comprehensive simulation study on the efficiency of employing adaptive protocols compared to the existing nonadaptive protocols for initializing sensor networks with random topology. In this regard, we propose adaptive network initialization protocols which integrate the initial neighbor discovery with link quality estimation process to initialize large-scale dense wireless sensor networks without requiring any parameter adjustment before network deployment. To the best of our knowledge, this work is the first attempt to provide a detailed simulation study on the performance of integrated neighbor discovery and link quality estimation protocols for initializing sensor networks. This study can help system designers to determine the most appropriate approach for different applications.

  10. Dose distribution in the thyroid and neighboring regions in therapy with 131I

    International Nuclear Information System (INIS)

    Monteiro, Rommel Barbosa; Bonifacio, Daniel Alexandre Baptista; Sa, Lidia Vasconcellos de

    2013-01-01

    In this work, simulations were performed with two types of computer simulators: the MIRD phantom and voxel phantom MASH, both of type adult male and in the standing position, coupled to the computational tool GATE (Geant4 Application for Tomographic Emission), to obtain the dose deposited in thyroid and neighboring regions

  11. Modeling the effect of neighboring grains on twin growth in HCP polycrystals

    Science.gov (United States)

    Kumar, M. Arul; Beyerlein, I. J.; Lebensohn, R. A.; Tomé, C. N.

    2017-09-01

    In this paper, we study the dependence of neighboring grain orientation on the local stress state around a deformation twin in a hexagonal close packed (HCP) crystal and its effects on the resistance against twin thickening. We use a recently developed, full-field elasto-visco-plastic formulation based on fast Fourier transforms that account for the twinning shear transformation imposed by the twin lamella. The study is applied to Mg, Zr and Ti, since these HCP metals tend to deform by activation of different types of slip modes. The analysis shows that the local stress along the twin boundary are strongly controlled by the relative orientation of the easiest deformation modes in the neighboring grain with respect to the twin lamella in the parent grain. A geometric expression that captures this parent-neighbor relationship is proposed and incorporated into a larger scale, mean-field visco-plastic self-consistent model to simulate the role of neighboring grain orientation on twin thickening. We demonstrate that the approach improves the prediction of twin area fraction distribution when compared with experimental observations.

  12. Recursive nearest neighbor search in a sparse and multiscale domain for comparing audio signals

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Daudet, Laurent

    2011-01-01

    We investigate recursive nearest neighbor search in a sparse domain at the scale of audio signals. Essentially, to approximate the cosine distance between the signals we make pairwise comparisons between the elements of localized sparse models built from large and redundant multiscale dictionaries...

  13. Collective Behaviors of Mobile Robots Beyond the Nearest Neighbor Rules With Switching Topology.

    Science.gov (United States)

    Ning, Boda; Han, Qing-Long; Zuo, Zongyu; Jin, Jiong; Zheng, Jinchuan

    2018-05-01

    This paper is concerned with the collective behaviors of robots beyond the nearest neighbor rules, i.e., dispersion and flocking, when robots interact with others by applying an acute angle test (AAT)-based interaction rule. Different from a conventional nearest neighbor rule or its variations, the AAT-based interaction rule allows interactions with some far-neighbors and excludes unnecessary nearest neighbors. The resulting dispersion and flocking hold the advantages of scalability, connectivity, robustness, and effective area coverage. For the dispersion, a spring-like controller is proposed to achieve collision-free coordination. With switching topology, a new fixed-time consensus-based energy function is developed to guarantee the system stability. An upper bound of settling time for energy consensus is obtained, and a uniform time interval is accordingly set so that energy distribution is conducted in a fair manner. For the flocking, based on a class of generalized potential functions taking nonsmooth switching into account, a new controller is proposed to ensure that the same velocity for all robots is eventually reached. A co-optimizing problem is further investigated to accomplish additional tasks, such as enhancing communication performance, while maintaining the collective behaviors of mobile robots. Simulation results are presented to show the effectiveness of the theoretical results.

  14. Who's Watching the Babies? Improving the Quality of Family, Friend, and Neighbor Child Care

    Science.gov (United States)

    Powell, Douglas R.

    2008-01-01

    One of the important influences on a child's development is the quality of his or her early care and education experiences. It is estimated that more than 1 million children in the U.S. are cared for while their parents are at work by nonlicensed caregivers who are family, friends, or neighbors - and these caregivers can be difficult to reach…

  15. Transfer-Efficient Face Routing Using the Planar Graphs of Neighbors in High Density WSNs

    Directory of Open Access Journals (Sweden)

    Eun-Seok Cho

    2017-10-01

    Full Text Available Face routing has been adopted in wireless sensor networks (WSNs where topological changes occur frequently or maintaining full network information is difficult. For message forwarding in networks, a planar graph is used to prevent looping, and because long edges are removed by planarization and the resulting planar graph is composed of short edges, and messages are forwarded along multiple nodes connected by them even though they can be forwarded directly. To solve this, face routing using information on all nodes within 2-hop range was adopted to forward messages directly to the farthest node within radio range. However, as the density of the nodes increases, network performance plunges because message transfer nodes receive and process increased node information. To deal with this problem, we propose a new face routing using the planar graphs of neighboring nodes to improve transfer efficiency. It forwards a message directly to the farthest neighbor and reduces loads and processing time by distributing network graph construction and planarization to the neighbors. It also decreases the amount of location information to be transmitted by sending information on the planar graph nodes rather than on all neighboring nodes. Simulation results show that it significantly improves transfer efficiency.

  16. The distribution of the number of node neighbors in random hypergraphs

    International Nuclear Information System (INIS)

    López, Eduardo

    2013-01-01

    Hypergraphs, the generalization of graphs in which edges become conglomerates of r nodes called hyperedges of rank r ⩾ 2, are excellent models to study systems with interactions that are beyond the pairwise level. For hypergraphs, the node degree ℓ (number of hyperedges connected to a node) and the number of neighbors k of a node differ from each other in contrast to the case of graphs, where counting the number of edges is equivalent to counting the number of neighbors. In this paper, I calculate the distribution of the number of node neighbors in random hypergraphs in which hyperedges of uniform rank r have a homogeneous (equal for all hyperedges) probability p to appear. This distribution is equivalent to the degree distribution of ensembles of graphs created as projections of hypergraph or bipartite network ensembles, where the projection connects any two nodes in the projected graph when they are also connected in the hypergraph or bipartite network. The calculation is non-trivial due to the possibility that neighbor nodes belong simultaneously to multiple hyperedges (node overlaps). From the exact results, the traditional asymptotic approximation to the distribution in the sparse regime (small p) where overlaps are ignored is rederived and improved; the approximation exhibits Poisson-like behavior accompanied by strong fluctuations modulated by power-law decays in the system size N with decay exponents equal to the minimum number of overlapping nodes possible for a given number of neighbors. It is shown that the dense limit cannot be explained if overlaps are ignored, and the correct asymptotic distribution is provided. The neighbor distribution requires the calculation of a new combinatorial coefficient Q r−1 (k, ℓ), which counts the number of distinct labeled hypergraphs of k nodes, ℓ hyperedges of rank r − 1, and where every node is connected to at least one hyperedge. Some identities of Q r−1 (k, ℓ) are derived and applied to the

  17. Impact of Training Bolivian Farmers on Integrated Pest Management and Diffusion of Knowledge to Neighboring Farmers.

    Science.gov (United States)

    Jørs, Erik; Konradsen, Flemming; Huici, Omar; Morant, Rafael C; Volk, Julie; Lander, Flemming

    2016-01-01

    Teaching farmers integrated pest management (IPM) in farmer field schools (FFS) has led to reduced pesticide use and safer handling. This article evaluates the long-term impact of training farmers on IPM and the diffusion of knowledge from trained farmers to neighboring farmers, a subject of importance to justify training costs and to promote a healthy and sustainable agriculture. Training on IPM of farmers took place from 2002 to 2004 in their villages in La Paz County, Bolivia, whereas dissemination of knowledge from trained farmer to neighboring farmer took place until 2009. To evaluate the impact of the intervention, self-reported knowledge and practice on pesticide handling and IPM among trained farmers (n = 23) and their neighboring farmers (n = 47) were analyzed in a follow-up study and compared in a cross-sectional analysis with a control group of farmers (n = 138) introduced in 2009. Variables were analyzed using χ2 test and analysis of variance (ANOVA). Trained farmers improved and performed significantly better in all tested variables than their neighboring farmers, although the latter also improved their performance from 2002 to 2009. Including a control group showed an increasing trend in all variables, with the control farmers having the poorest performance and trained farmers the best. The same was seen in an aggregated variable where trained farmers had a mean score of 16.55 (95% confidence interval [CI]: 15.45-17.65), neighboring farmers a mean score of 11.97 (95% CI: 10.56-13.38), and control farmers a mean score of 9.18 (95% CI: 8.55-9.80). Controlling for age and living altitude did not change these results. Trained farmers and their neighboring farmers improved and maintained knowledge and practice on IPM and pesticide handling. Diffusion of knowledge from trained farmers might explain the better performance of the neighboring farmers compared with the control farmers. Dissemination of knowledge can contribute to justify the cost and convince

  18. Fluorescence and thermoluminescence in silicon oxide films rich in silicon

    International Nuclear Information System (INIS)

    Berman M, D.; Piters, T. M.; Aceves M, M.; Berriel V, L. R.; Luna L, J. A.

    2009-10-01

    In this work we determined the fluorescence and thermoluminescence (TL) creation spectra of silicon rich oxide films (SRO) with three different silicon excesses. To study the TL of SRO, 550 nm of SRO film were deposited by Low Pressure Chemical Vapor Deposition technique on N-type silicon substrates with resistivity in the order of 3 to 5 Ω-cm with silicon excess controlled by the ratio of the gases used in the process, SRO films with Ro= 10, 20 and 30 (12-6% silicon excess) were obtained. Then, they were thermally treated in N 2 at high temperatures to diffuse and homogenize the silicon excess. In the fluorescence spectra two main emission regions are observed, one around 400 nm and one around 800 nm. TL creation spectra were determined by plotting the integrated TL intensity as function of the excitation wavelength. (Author)

  19. The CMS silicon tracker

    International Nuclear Information System (INIS)

    Focardi, E.; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B; Ciampolini, P.; Civinini, C.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell'Orso, R.; Della Marina, R.; Dutta, S.; Eklund, C.; Feld, L.; Fiore, L.; French, M.; Freudenreich, K.; Frey, A.; Fuertjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Leubelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B.Mc; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Rizzo, F.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B.

    2000-01-01

    This paper describes the Silicon microstrip Tracker of the CMS experiment at LHC. It consists of a barrel part with 5 layers and two endcaps with 10 disks each. About 10 000 single-sided equivalent modules have to be built, each one carrying two daisy-chained silicon detectors and their front-end electronics. Back-to-back modules are used to read-out the radial coordinate. The tracker will be operated in an environment kept at a temperature of T=-10 deg. C to minimize the Si sensors radiation damage. Heavily irradiated detectors will be safely operated due to the high-voltage capability of the sensors. Full-size mechanical prototypes have been built to check the system aspects before starting the construction

  20. Undepleted silicon detectors

    International Nuclear Information System (INIS)

    Rancoita, P.G.; Seidman, A.

    1985-01-01

    Large-size silicon detectors employing relatively low resistivity material can be used in electromagnetic calorimetry. They can operate in strong magnetic fields, under geometric constraints and with microstrip detectors a high resolution can be achieved. Low noise large capacitance oriented electronics was developed to enable good signal-to-noise ratio for single relativistic particles traversing large area detectors. In undepleted silicon detectors, the charge migration from the field-free region has been investigated by comparing the expected peak position (from the depleted layer only) of the energy-loss of relativistic electrons with the measured one. Furthermore, the undepleted detectors have been employed in a prototype of Si/W electromagnetic colorimeter. The sensitive layer was found to be systematically larger than the depleted one

  1. Silicon nanowire transistors

    CERN Document Server

    Bindal, Ahmet

    2016-01-01

    This book describes the n and p-channel Silicon Nanowire Transistor (SNT) designs with single and dual-work functions, emphasizing low static and dynamic power consumption. The authors describe a process flow for fabrication and generate SPICE models for building various digital and analog circuits. These include an SRAM, a baseband spread spectrum transmitter, a neuron cell and a Field Programmable Gate Array (FPGA) platform in the digital domain, as well as high bandwidth single-stage and operational amplifiers, RF communication circuits in the analog domain, in order to show this technology’s true potential for the next generation VLSI. Describes Silicon Nanowire (SNW) Transistors, as vertically constructed MOS n and p-channel transistors, with low static and dynamic power consumption and small layout footprint; Targets System-on-Chip (SoC) design, supporting very high transistor count (ULSI), minimal power consumption requiring inexpensive substrates for packaging; Enables fabrication of different types...

  2. Amorphous silicon radiation detectors

    Science.gov (United States)

    Street, Robert A.; Perez-Mendez, Victor; Kaplan, Selig N.

    1992-01-01

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

  3. Electron beam silicon purification

    Energy Technology Data Exchange (ETDEWEB)

    Kravtsov, Anatoly [SIA ' ' KEPP EU' ' , Riga (Latvia); Kravtsov, Alexey [' ' KEPP-service' ' Ltd., Moscow (Russian Federation)

    2014-11-15

    Purification of heavily doped electronic grade silicon by evaporation of N-type impurities with electron beam heating was investigated in process with a batch weight up to 50 kilos. Effective temperature of the melt, an indicative parameter suitable for purification process characterization was calculated and appeared to be stable for different load weight processes. Purified material was successfully approbated in standard CZ processes of three different companies. Each company used its standard process and obtained CZ monocrystals applicable for photovoltaic application. These facts enable process to be successfully scaled up to commercial volumes (150-300 kg) and yield solar grade silicon. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Electrometallurgy of Silicon

    Science.gov (United States)

    1988-01-01

    wind, plants, and water impounded in elevated reservoirs. Photovoltaic or solar cells, which convert sunlight directly to electricity, belongs tc, the...on record is that of St. Claire DeVille, who claimed that silicon was produced by electrolysing an impure melt of NaAlC14, but his material did not...this composition and purified melts were electrolysed at about 14500C in graphite crucible and using graphite electrodes. Applied potentials were

  5. Liquid Silicon Pouch Anode

    Science.gov (United States)

    2017-09-06

    Number 15/696,426 Filing Date 6 September 2017 Inventor Charles J. Patrissi et al Address any questions concerning this matter to the...silicon-based anodes during cycling, lithium insertion and deinsertion. Mitigation of this problem has long been sought and will result in improved...design shown. [0032] It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been

  6. The CMS silicon tracker

    International Nuclear Information System (INIS)

    D'Alessandro, R.; Biggeri, U.; Bruzzi, M.; Catacchini, E.; Civinini, C.; Focardi, E.; Lenzi, M.; Loreti, M.; Meschini, M.; Parrini, G.; Pieri, M.; Albergo, S.; Boemi, D.; Potenza, R.; Tricomi, A.; Angarano, M.; Creanza, D.; Palma, M. de; Fiore, L.; Maggi, G.; My, S.; Raso, G.; Selvaggi, G.; Tempesta, P.; Azzi, P.; Bacchetta, N.; Bisello, D.; Candelori, A.; Castro, A.; Da Rold, M.; Giraldo, A.; Martignon, G.; Paccagnella, A.; Stavitsky, I.; Babucci, E.; Bartalini, P.; Bilei, G.M.; Checcucci, B.; Ciampolini, P.; Lariccia, P.; Mantovani, G.; Passeri, D.; Santocchia, A.; Servoli, L.; Wang, Y.; Bagliesi, G.; Basti, A.; Bosi, F.; Borello, L.; Bozzi, C.; Castaldi, R.; Dell'Orso, R.; Giassi, A.; Messineo, A.; Palla, F.; Raffaelli, F.; Sguazzoni, G.; Starodumov, A.; Tonelli, G.; Vannini, C.; Verdini, P.G.; Xie, Z.; Breuker, H.; Caner, A.; Elliott-Peisert, A.; Feld, L.; Glessing, B.; Hammerstrom, R.; Huhtinen, M.; Mannelli, M.; Marchioro, A.; Schmitt, B.; Stefanini, G.; Connotte, J.; Gu, W.H.; Luebelsmeyer, K.; Pandoulas, D.; Siedling, R.; Wittmer, B.; Della Marina, R.; Freudenreich, K.; Lustermann, W.; Viertel, G.; Eklund, C.; Karimaeki, V.; Skog, K.; French, M.; Hall, G.; Mc Evoy, B.; Raymond, M.; Hrubec, J.; Krammer, M.; Piperov, S.; Tuuva, T.; Watts, S.; Silvestris, L.

    1998-01-01

    The new silicon tracker layout (V4) is presented. The system aspects of the construction are discussed together with the expected tracking performance. Because of the high radiation environment in which the detectors will operate, particular care has been devoted to the study of the characteristics of heavily irradiated detectors. This includes studies on performance (charge collection, cluster size, resolution, efficiency) as a function of the bias voltage, integrated fluence, incidence angle and temperature. (author)

  7. Selfsupported epitaxial silicon films

    International Nuclear Information System (INIS)

    Lazarovici, D.; Popescu, A.

    1975-01-01

    The methods of removing the p or p + support of an n-type epitaxial silicon layer using electrochemical etching are described. So far, only n + -n junctions have been processed. The condition of anodic dissolution for some values of the support and layer resistivity are given. By this method very thin single crystal selfsupported targets of convenient areas can be obtained for channeling - blocking experiments

  8. Silicon and Civilization,

    Science.gov (United States)

    1980-11-04

    of a diamond. 7. The particular physical and chemical properties of silicon resulted in the fact that in the periodic system it was found in the III...small quantities. Silica is found in blades of grass and grain, in reed and bamboo shoots, where it serves to stiffen the stalk. 2. Diatomite ... properties desired in technology. Quartz glass is very resistant to temperature change since it has a very small coefficient of thermal expansion, is

  9. Porous silicon: silicon quantum dots for photonic applications

    International Nuclear Information System (INIS)

    Pavesi, L.; Guardini, R.

    1996-01-01

    Porous silicon formation and structure characterization are briefly illustrated. Its luminescence properties rae presented and interpreted on the basis of exciton recombination in quantum dot structures: the trap-controlled hopping mechanism is used to describe the recombination dynamics. Porous silicon application to photonic devices is considered: porous silicon multilayer in general, and micro cavities in particular are described. The present situation in the realization of porous silicon LEDs is considered, and future developments in this field of research are suggested. (author). 30 refs., 30 figs., 13 tabs

  10. Photovoltaic characteristics of porous silicon /(n+ - p) silicon solar cells

    International Nuclear Information System (INIS)

    Dzhafarov, T.D.; Aslanov, S.S.; Ragimov, S.H.; Sadigov, M.S.; Nabiyeva, A.F.; Yuksel, Aydin S.

    2012-01-01

    Full text : The purpose of this work is to improve the photovoltaic parameters of the screen-printed silicon solar cells by formation the nano-porous silicon film on the frontal surface of the cell. The photovoltaic characteristics of two type silicon solar cells with and without porous silicon layer were measured and compared. A remarkable increment of short-circuit current density and the efficiency by 48 percent and 20 percent, respectively, have been achieved for PS/(n + - pSi) solar cell comparing to (n + - p)Si solar cell without PS layer

  11. Silicon photonics fundamentals and devices

    CERN Document Server

    Deen, M Jamal

    2012-01-01

    The creation of affordable high speed optical communications using standard semiconductor manufacturing technology is a principal aim of silicon photonics research. This would involve replacing copper connections with optical fibres or waveguides, and electrons with photons. With applications such as telecommunications and information processing, light detection, spectroscopy, holography and robotics, silicon photonics has the potential to revolutionise electronic-only systems. Providing an overview of the physics, technology and device operation of photonic devices using exclusively silicon and related alloys, the book includes: * Basic Properties of Silicon * Quantum Wells, Wires, Dots and Superlattices * Absorption Processes in Semiconductors * Light Emitters in Silicon * Photodetectors , Photodiodes and Phototransistors * Raman Lasers including Raman Scattering * Guided Lightwaves * Planar Waveguide Devices * Fabrication Techniques and Material Systems Silicon Photonics: Fundamentals and Devices outlines ...

  12. Radiation Hardening of Silicon Detectors

    CERN Multimedia

    Leroy, C; Glaser, M

    2002-01-01

    %RD48 %title\\\\ \\\\Silicon detectors will be widely used in experiments at the CERN Large Hadron Collider where high radiation levels will cause significant bulk damage. In addition to increased leakage current and charge collection losses worsening the signal to noise, the induced radiation damage changes the effective doping concentration and represents the limiting factor to long term operation of silicon detectors. The objectives are to develop radiation hard silicon detectors that can operate beyond the limits of the present devices and that ensure guaranteed operation for the whole lifetime of the LHC experimental programme. Radiation induced defect modelling and experimental results show that the silicon radiation hardness depends on the atomic impurities present in the initial monocrystalline material.\\\\ \\\\ Float zone (FZ) silicon materials with addition of oxygen, carbon, nitrogen, germanium and tin were produced as well as epitaxial silicon materials with epilayers up to 200 $\\mu$m thickness. Their im...

  13. Amorphous silicon based particle detectors

    OpenAIRE

    Wyrsch, N.; Franco, A.; Riesen, Y.; Despeisse, M.; Dunand, S.; Powolny, F.; Jarron, P.; Ballif, C.

    2012-01-01

    Radiation hard monolithic particle sensors can be fabricated by a vertical integration of amorphous silicon particle sensors on top of CMOS readout chip. Two types of such particle sensors are presented here using either thick diodes or microchannel plates. The first type based on amorphous silicon diodes exhibits high spatial resolution due to the short lateral carrier collection. Combination of an amorphous silicon thick diode with microstrip detector geometries permits to achieve micromete...

  14. Characterization of Czochralski Silicon Detectors

    OpenAIRE

    Luukka, Panja-Riina; Haerkoenen, Jaakko

    2012-01-01

    This thesis describes the characterization of irradiated and non-irradiated segmenteddetectors made of high-resistivity (>1 kΩcm) magnetic Czochralski (MCZ) silicon. It isshown that the radiation hardness (RH) of the protons of these detectors is higher thanthat of devices made of traditional materials such as Float Zone (FZ) silicon or DiffusionOxygenated Float Zone (DOFZ) silicon due to the presence of intrinsic oxygen (> 5 x1017 cm-3). The MCZ devices therefore present an interesting alter...

  15. Laboratory course on silicon sensors

    CERN Document Server

    Crescio, E; Roe, S; Rudge, A

    2003-01-01

    The laboratory course consisted of four different mini sessions, in order to give the student some hands-on experience on various aspects of silicon sensors and related integrated electronics. The four experiments were. 1. Characterisation of silicon diodes for particle detection 2. Study of noise performance of the Viking readout circuit 3. Study of the position resolution of a silicon microstrip sensor 4. Study of charge transport in silicon with a fast amplifier The data in the following were obtained during the ICFA school by the students.

  16. Silicon processing for photovoltaics II

    CERN Document Server

    Khattak, CP

    2012-01-01

    The processing of semiconductor silicon for manufacturing low cost photovoltaic products has been a field of increasing activity over the past decade and a number of papers have been published in the technical literature. This volume presents comprehensive, in-depth reviews on some of the key technologies developed for processing silicon for photovoltaic applications. It is complementary to Volume 5 in this series and together they provide the only collection of reviews in silicon photovoltaics available.The volume contains papers on: the effect of introducing grain boundaries in silicon; the

  17. The neighbor enclosed area tracking algorithm and its application to cyclone merger in the midlatitudes

    Science.gov (United States)

    Inatsu, Masaru; Amada, Shotarou; Satake, Yuya

    2010-05-01

    The neighbor enclosed area tracking (NEAT) algorithm is proposed as an alternative method to conventional point-to-point cyclone tracking approaches. Most automated Lagrangian tracking algorithms contain three procedures: cyclone identification, cyclone tracking, and quantification of cyclone intensity and activity. The cyclone identification was simply based on a comparison of neighboring grid points; cyclone tracking mainly employed a near-neighbor point search to neighbor-time cyclone-center datasets; and cyclone intensity and activity are mainly quantified as cyclone track density, and other accompanying products such as genesis and lysis densities, mean lifetime, average moving vector, and mean growth rate can also be obtained in the final procedure. But a crucial problem in the above technique is its requirement of some complicated connecting conditions for near-neighbor tracking. To overcome the problem, NEAT completes cyclone identification and cyclone tracking in a single process of equivalent labeling for spatiotemporally connected domains, i.e., if two spatially enclosed areas in a neighboring time frame overlap, they should be connected. NEAT enables us to count the genesis and tracks of individual cyclones as the conventional tracking. Moreover, NEAT has the ability to produce fruitful information on cyclone mergers and separations, cyclone shape, and material transport by individual eddies (the latter two features will be reported elsewhere). There are many possible applications of NEAT to meteorology and oceanography, but now we focus on the situation, well-known by Japanese synopticians, that two cyclones pass respectively over the north and south of Japan and then they frequently merge and are rapidly deepened in the western Pacific. For the case, the southern cyclones tend to be stimulated just above the sea surface temperature front to the north of oceanic western boundary currents, while the northern cyclones, moving eastward along the polar

  18. 75 FR 62412 - Notice of Proposed Information Collection: Comment Request; HUD-Owned Real Estate-Good Neighbor...

    Science.gov (United States)

    2010-10-08

    ... DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT [Docket No. FR-5380-N-36] Notice of Proposed Information Collection: Comment Request; HUD- Owned Real Estate-Good Neighbor Next Door Program AGENCY: Office... information: Title of Proposal: HUD-Owned Real Estate-Good Neighbor Next Door Program. OMB Control Number, if...

  19. A two-step nearest neighbors algorithm using satellite imagery for predicting forest structure within species composition classes

    Science.gov (United States)

    Ronald E. McRoberts

    2009-01-01

    Nearest neighbors techniques have been shown to be useful for predicting multiple forest attributes from forest inventory and Landsat satellite image data. However, in regions lacking good digital land cover information, nearest neighbors selected to predict continuous variables such as tree volume must be selected without regard to relevant categorical variables such...

  20. Electrical leakage phenomenon in heteroepitaxial cubic silicon carbide on silicon

    Science.gov (United States)

    Pradeepkumar, Aiswarya; Zielinski, Marcin; Bosi, Matteo; Verzellesi, Giovanni; Gaskill, D. Kurt; Iacopi, Francesca

    2018-06-01

    Heteroepitaxial 3C-SiC films on silicon substrates are of technological interest as enablers to integrate the excellent electrical, electronic, mechanical, thermal, and epitaxial properties of bulk silicon carbide into well-established silicon technologies. One critical bottleneck of this integration is the establishment of a stable and reliable electronic junction at the heteroepitaxial interface of the n-type SiC with the silicon substrate. We have thus investigated in detail the electrical and transport properties of heteroepitaxial cubic silicon carbide films grown via different methods on low-doped and high-resistivity silicon substrates by using van der Pauw Hall and transfer length measurements as test vehicles. We have found that Si and C intermixing upon or after growth, particularly by the diffusion of carbon into the silicon matrix, creates extensive interstitial carbon traps and hampers the formation of a stable rectifying or insulating junction at the SiC/Si interface. Although a reliable p-n junction may not be realistic in the SiC/Si system, we can achieve, from a point of view of the electrical isolation of in-plane SiC structures, leakage suppression through the substrate by using a high-resistivity silicon substrate coupled with deep recess etching in between the SiC structures.

  1. Light emitting structures porous silicon-silicon substrate

    International Nuclear Information System (INIS)

    Monastyrskii, L.S.; Olenych, I.B.; Panasjuk, M.R.; Savchyn, V.P.

    1999-01-01

    The research of spectroscopic properties of porous silicon has been done. Complex of photoluminescence, electroluminescence, cathodoluminescence, thermostimulated depolarisation current analyte methods have been applied to study of geterostructures and free layers of porous silicon. Light emitting processes had tendency to decrease. The character of decay for all kinds of luminescence were different

  2. Indentation fatigue in silicon nitride, alumina and silicon carbide ...

    Indian Academy of Sciences (India)

    Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz. 1 m and 25 m, and a sintered silicon carbide (SSiC) are reported. The RIF experiments were conducted using a Vicker's ...

  3. Multi-strategy based quantum cost reduction of linear nearest-neighbor quantum circuit

    Science.gov (United States)

    Tan, Ying-ying; Cheng, Xue-yun; Guan, Zhi-jin; Liu, Yang; Ma, Haiying

    2018-03-01

    With the development of reversible and quantum computing, study of reversible and quantum circuits has also developed rapidly. Due to physical constraints, most quantum circuits require quantum gates to interact on adjacent quantum bits. However, many existing quantum circuits nearest-neighbor have large quantum cost. Therefore, how to effectively reduce quantum cost is becoming a popular research topic. In this paper, we proposed multiple optimization strategies to reduce the quantum cost of the circuit, that is, we reduce quantum cost from MCT gates decomposition, nearest neighbor and circuit simplification, respectively. The experimental results show that the proposed strategies can effectively reduce the quantum cost, and the maximum optimization rate is 30.61% compared to the corresponding results.

  4. A dynamic evolutionary clustering perspective: Community detection in signed networks by reconstructing neighbor sets

    Science.gov (United States)

    Chen, Jianrui; Wang, Hua; Wang, Lina; Liu, Weiwei

    2016-04-01

    Community detection in social networks has been intensively studied in recent years. In this paper, a novel similarity measurement is defined according to social balance theory for signed networks. Inter-community positive links are found and deleted due to their low similarity. The positive neighbor sets are reconstructed by this method. Then, differential equations are proposed to imitate the constantly changing states of nodes. Each node will update its state based on the difference between its state and average state of its positive neighbors. Nodes in the same community will evolve together with time and nodes in the different communities will evolve far away. Communities are detected ultimately when states of nodes are stable. Experiments on real world and synthetic networks are implemented to verify detection performance. The thorough comparisons demonstrate the presented method is more efficient than two acknowledged better algorithms.

  5. Fusion yield rate recovery by escaping hot-spot fast ions in the neighboring fuel layer

    Science.gov (United States)

    Tang, Xian-Zhu; McDevitt, C. J.; Guo, Zehua; Berk, H. L.

    2014-02-01

    Free-streaming loss by fast ions can deplete the tail population in the hot spot of an inertial confinement fusion (ICF) target. Escaping fast ions in the neighboring fuel layer of a cryogenic target can produce a surplus of fast ions locally. In contrast to the Knudsen layer effect that reduces hot-spot fusion reactivity due to tail ion depletion, the inverse Knudsen layer effect increases fusion reactivity in the neighboring fuel layer. In the case of a burning ICF target in the presence of significant hydrodynamic mix which aggravates the Knudsen layer effect, the yield recovery largely compensates for the yield reduction. For mix-dominated sub-ignition targets, the yield reduction is the dominant process.

  6. Knowledgeable Neighbors: a mobile clinic model for disease prevention and screening in underserved communities.

    Science.gov (United States)

    Hill, Caterina; Zurakowski, David; Bennet, Jennifer; Walker-White, Rainelle; Osman, Jamie L; Quarles, Aaron; Oriol, Nancy

    2012-03-01

    The Family Van mobile health clinic uses a "Knowledgeable Neighbor" model to deliver cost-effective screening and prevention activities in underserved neighborhoods in Boston, MA. We have described the Knowledgeable Neighbor model and used operational data collected from 2006 to 2009 to evaluate the service. The Family Van successfully reached mainly minority low-income men and women. Of the clients screened, 60% had previously undetected elevated blood pressure, 14% had previously undetected elevated blood glucose, and 38% had previously undetected elevated total cholesterol. This represents an important model for reaching underserved communities to deliver proven cost-effective prevention activities, both to help control health care costs and to reduce health disparities.

  7. ANN-Benchmarks: A Benchmarking Tool for Approximate Nearest Neighbor Algorithms

    DEFF Research Database (Denmark)

    Aumüller, Martin; Bernhardsson, Erik; Faithfull, Alexander

    2017-01-01

    This paper describes ANN-Benchmarks, a tool for evaluating the performance of in-memory approximate nearest neighbor algorithms. It provides a standard interface for measuring the performance and quality achieved by nearest neighbor algorithms on different standard data sets. It supports several...... visualise these as images, Open image in new window plots, and websites with interactive plots. ANN-Benchmarks aims to provide a constantly updated overview of the current state of the art of k-NN algorithms. In the short term, this overview allows users to choose the correct k-NN algorithm and parameters...... for their similarity search task; in the longer term, algorithm designers will be able to use this overview to test and refine automatic parameter tuning. The paper gives an overview of the system, evaluates the results of the benchmark, and points out directions for future work. Interestingly, very different...

  8. Use of the neighboring orbital model for analysis of electronic coupling in Class III intervalence compounds

    International Nuclear Information System (INIS)

    Nelsen, Stephen F.; Weaver, Michael N.; Luo Yun; Lockard, Jenny V.; Zink, Jeffrey I.

    2006-01-01

    Symmetrical charge-delocalized intervalence radical ions should not be described by the traditional two-state model that has been so successful for their localized counterparts. If they lack direct overlap between their charge-bearing units (M), their diabatic orbitals have an equal energy pair of symmetrized M-centered combination orbitals that are symmetric (S) or antisymmetric (A) with respect to a symmetry element at the center of the molecule. The M combination orbitals will mix separately with bridge orbitals of the same symmetry. We call the simplest useful model for this situation the neighboring orbital model, which uses the S and A bridge orbitals of high overlap that lie closest in energy to the M orbital pair, resulting in two two-state models that have a common energy for one pair. This model is developed quantitatively, and examples having 1, 3, 5, and 7 electrons in the neighboring orbitals are illustrated

  9. Quantum Algorithm for K-Nearest Neighbors Classification Based on the Metric of Hamming Distance

    Science.gov (United States)

    Ruan, Yue; Xue, Xiling; Liu, Heng; Tan, Jianing; Li, Xi

    2017-11-01

    K-nearest neighbors (KNN) algorithm is a common algorithm used for classification, and also a sub-routine in various complicated machine learning tasks. In this paper, we presented a quantum algorithm (QKNN) for implementing this algorithm based on the metric of Hamming distance. We put forward a quantum circuit for computing Hamming distance between testing sample and each feature vector in the training set. Taking advantage of this method, we realized a good analog for classical KNN algorithm by setting a distance threshold value t to select k - n e a r e s t neighbors. As a result, QKNN achieves O( n 3) performance which is only relevant to the dimension of feature vectors and high classification accuracy, outperforms Llyod's algorithm (Lloyd et al. 2013) and Wiebe's algorithm (Wiebe et al. 2014).

  10. Impurity-defect complexes in hydrogenated amorphous silicon

    International Nuclear Information System (INIS)

    Yang, L.H.; Fong, C.Y.; Nichols, C.S.

    1991-01-01

    The two most outstanding features observed for dopants in hydrogenated amorphous silicon (a-Si:H)-a shift in the Fermi level accompanied by an increase in the defect density and an absence of degenerate doping have previously been postulated to stem from the formation of substitutional dopant-dangling bond complexes. Using first-principles self-consistent pseudopotential calculations in conjunction with a supercell model for the amorphous network and the ability of network relaxation from the first-principles results. The authors have studied the electronic and structural properties of substitutional fourfold-coordinated phosphorus and boron at the second neighbor position to a dangling bond defect. This paper demonstrates that such impurity-defect complexes can account for the general features observed experimentally in doped a-Si:H

  11. Chaotic Synchronization in Nearest-Neighbor Coupled Networks of 3D CNNs

    OpenAIRE

    Serrano-Guerrero, H.; Cruz-Hernández, C.; López-Gutiérrez, R.M.; Cardoza-Avendaño, L.; Chávez-Pérez, R.A.

    2013-01-01

    In this paper, a synchronization of Cellular Neural Networks (CNNs) in nearest-neighbor coupled arrays, is numerically studied. Synchronization of multiple chaotic CNNs is achieved by appealing to complex systems theory. In particular, we consider dynamical networks composed by 3D CNNs, as interconnected nodes, where the interactions in the networks are defined by coupling the first state of each node. Four cases of interest are considered: i) synchronization without chaotic master, ii) maste...

  12. FCNN-MR: A Parallel Instance Selection Method Based on Fast Condensed Nearest Neighbor Rule

    OpenAIRE

    Lu Si; Jie Yu; Shasha Li; Jun Ma; Lei Luo; Qingbo Wu; Yongqi Ma; Zhengji Liu

    2017-01-01

    Instance selection (IS) technique is used to reduce the data size to improve the performance of data mining methods. Recently, to process very large data set, several proposed methods divide the training set into some disjoint subsets and apply IS algorithms independently to each subset. In this paper, we analyze the limitation of these methods and give our viewpoint about how to divide and conquer in IS procedure. Then, based on fast condensed nearest neighbor (FCNN) rul...

  13. Keeping up With The Neighbors: Nonproliferation and Implementation of UNSCR 1540

    Science.gov (United States)

    2016-02-15

    be respectful of the rule of law and a competitive participatory democracy , yet fail to implement UNSCR 1540, just like its neighbors. Discussion...risk-taking between 1816 and 1992. They found a strong association between conservative governmental decision-making and not only democracies , but...specifically those democracies with highly competitive political systems.46 In addition, Bruce Bueno de Mesquita, et.al. found a significant

  14. An Improvement To The k-Nearest Neighbor Classifier For ECG Database

    Science.gov (United States)

    Jaafar, Haryati; Hidayah Ramli, Nur; Nasir, Aimi Salihah Abdul

    2018-03-01

    The k nearest neighbor (kNN) is a non-parametric classifier and has been widely used for pattern classification. However, in practice, the performance of kNN often tends to fail due to the lack of information on how the samples are distributed among them. Moreover, kNN is no longer optimal when the training samples are limited. Another problem observed in kNN is regarding the weighting issues in assigning the class label before classification. Thus, to solve these limitations, a new classifier called Mahalanobis fuzzy k-nearest centroid neighbor (MFkNCN) is proposed in this study. Here, a Mahalanobis distance is applied to avoid the imbalance of samples distribition. Then, a surrounding rule is employed to obtain the nearest centroid neighbor based on the distributions of training samples and its distance to the query point. Consequently, the fuzzy membership function is employed to assign the query point to the class label which is frequently represented by the nearest centroid neighbor Experimental studies from electrocardiogram (ECG) signal is applied in this study. The classification performances are evaluated in two experimental steps i.e. different values of k and different sizes of feature dimensions. Subsequently, a comparative study of kNN, kNCN, FkNN and MFkCNN classifier is conducted to evaluate the performances of the proposed classifier. The results show that the performance of MFkNCN consistently exceeds the kNN, kNCN and FkNN with the best classification rates of 96.5%.

  15. Investment Incentives and Effective Tax Rates in the Philippines; A Comparison With Neighboring Countries

    OpenAIRE

    Alexander D Klemm; Dennis P Botman; Reza Baqir

    2008-01-01

    We compare the general tax provisions and investment incentives in the Philippines to six other east-Asian economies-Malaysia, Indonesia, Lao, Vietnam, Cambodia, and Thailand. We calculate effective tax rates and find that general effective tax rates are relatively high in the Philippines, while investment incentives are comparable to those in neighboring countries. Tax holidays are most attractive for very profitable firms, creating redundancy, and for investment in short-lived assets. We al...

  16. The Tragedy of Your Upstairs Neighbors: Is the Airbnb Negative Externality Internalized?

    OpenAIRE

    Horton, John J.

    2015-01-01

    A commonly expressed concern about the rise of the peer-to-peer rental market Airbnb is that hosts---those renting out their properties---impose costs on their unwitting neighbors. I consider the question of whether apartment building owners will, in a competitive rental market, set a building-specific Airbnb hosting policy that is socially efficient. I find that if tenants can sort across apartments based on the owners policy then the equilibrium fraction of buildings allowing Airbnb listing...

  17. Specific Protein Markers for Stem Cell Cross-Talk with Neighboring Cells in the Environment

    OpenAIRE

    Park, Kyung Soo; Shin, Seung Won; Choi, Jeong-Woo; Um, Soong Ho

    2013-01-01

    A stem cell interacts with the neighboring cells in its environment. To maintain a living organism’s metabolism, either cell-cell or cell-environment interactions may be significant. Usually, these cells communicate with each other through biological signaling by interactive behaviors of primary proteins or complementary chemicals. The signaling intermediates offer the stem cell’s functionality on its metabolism. With the rapid advent of omics technologies, various specific markers by which s...

  18. A Hybrid Instance Selection Using Nearest-Neighbor for Cross-Project Defect Prediction

    Institute of Scientific and Technical Information of China (English)

    Duksan Ryu; Jong-In Jang; Jongmoon Baik; Member; ACM; IEEE

    2015-01-01

    Software defect prediction (SDP) is an active research field in software engineering to identify defect-prone modules. Thanks to SDP, limited testing resources can be effectively allocated to defect-prone modules. Although SDP requires suffcient local data within a company, there are cases where local data are not available, e.g., pilot projects. Companies without local data can employ cross-project defect prediction (CPDP) using external data to build classifiers. The major challenge of CPDP is different distributions between training and test data. To tackle this, instances of source data similar to target data are selected to build classifiers. Software datasets have a class imbalance problem meaning the ratio of defective class to clean class is far low. It usually lowers the performance of classifiers. We propose a Hybrid Instance Selection Using Nearest-Neighbor (HISNN) method that performs a hybrid classification selectively learning local knowledge (via k-nearest neighbor) and global knowledge (via na¨ıve Bayes). Instances having strong local knowledge are identified via nearest-neighbors with the same class label. Previous studies showed low PD (probability of detection) or high PF (probability of false alarm) which is impractical to use. The experimental results show that HISNN produces high overall performance as well as high PD and low PF.

  19. Who's your neighbor? Acoustic cues to individual identity in red squirrel Tamiasciurus hudsonicus rattle calls

    Directory of Open Access Journals (Sweden)

    Shannon M. DIGWEED, Drew RENDALL, Teana IMBEAU

    2012-10-01

    Full Text Available North American red squirrels Tamiasciurus hudsonicus often produce a loud territorial rattle call when conspecifics enter or invade a territory. Previous playback experiments suggest that the territorial rattle call may indicate an invader's identity as squirrels responded more intensely to calls played from strangers than to calls played from neighbors. This dear-enemy effect is well known in a variety of bird and mammal species and functions to reduce aggressive interactions between known neighbors. However, although previous experiments on red squirrels suggest some form of individual differentiation and thus recognition, detailed acoustic analysis of potential acoustic cues in rattle calls have not been conducted. If calls function to aid in conspecific identification in order to mitigate aggressive territorial interactions, we would expect that individual recognition cues would be acoustically represented. Our work provides a detailed analysis of acoustic cues to identity within rattle calls. A total of 225 calls across 32 individual squirrels from Sheep River Provincial Park, Kananaskis, AB, Canada, were analyzed with discriminant function analysis for potential acoustic cues to individual identity. Initial analysis of all individuals revealed a reliable acoustic differentiation across individuals. A more detailed analysis of clusters of neighboring squirrels was performed and results again indicated a statistically significant likelihood that calls were assigned correctly to specific squirrels (55%-75% correctly assigned; in other words squirrels have distinct voices that should allow for individual identification and discrimination by conspecifics [Current Zoology 58 (5: 758–764, 2012].

  20. Multidimensional k-nearest neighbor model based on EEMD for financial time series forecasting

    Science.gov (United States)

    Zhang, Ningning; Lin, Aijing; Shang, Pengjian

    2017-07-01

    In this paper, we propose a new two-stage methodology that combines the ensemble empirical mode decomposition (EEMD) with multidimensional k-nearest neighbor model (MKNN) in order to forecast the closing price and high price of the stocks simultaneously. The modified algorithm of k-nearest neighbors (KNN) has an increasingly wide application in the prediction of all fields. Empirical mode decomposition (EMD) decomposes a nonlinear and non-stationary signal into a series of intrinsic mode functions (IMFs), however, it cannot reveal characteristic information of the signal with much accuracy as a result of mode mixing. So ensemble empirical mode decomposition (EEMD), an improved method of EMD, is presented to resolve the weaknesses of EMD by adding white noise to the original data. With EEMD, the components with true physical meaning can be extracted from the time series. Utilizing the advantage of EEMD and MKNN, the new proposed ensemble empirical mode decomposition combined with multidimensional k-nearest neighbor model (EEMD-MKNN) has high predictive precision for short-term forecasting. Moreover, we extend this methodology to the case of two-dimensions to forecast the closing price and high price of the four stocks (NAS, S&P500, DJI and STI stock indices) at the same time. The results indicate that the proposed EEMD-MKNN model has a higher forecast precision than EMD-KNN, KNN method and ARIMA.

  1. Resampling nucleotide sequences with closest-neighbor trimming and its comparison to other methods.

    Directory of Open Access Journals (Sweden)

    Kouki Yonezawa

    Full Text Available A large number of nucleotide sequences of various pathogens are available in public databases. The growth of the datasets has resulted in an enormous increase in computational costs. Moreover, due to differences in surveillance activities, the number of sequences found in databases varies from one country to another and from year to year. Therefore, it is important to study resampling methods to reduce the sampling bias. A novel algorithm-called the closest-neighbor trimming method-that resamples a given number of sequences from a large nucleotide sequence dataset was proposed. The performance of the proposed algorithm was compared with other algorithms by using the nucleotide sequences of human H3N2 influenza viruses. We compared the closest-neighbor trimming method with the naive hierarchical clustering algorithm and [Formula: see text]-medoids clustering algorithm. Genetic information accumulated in public databases contains sampling bias. The closest-neighbor trimming method can thin out densely sampled sequences from a given dataset. Since nucleotide sequences are among the most widely used materials for life sciences, we anticipate that our algorithm to various datasets will result in reducing sampling bias.

  2. Equivalent charge source model based iterative maximum neighbor weight for sparse EEG source localization.

    Science.gov (United States)

    Xu, Peng; Tian, Yin; Lei, Xu; Hu, Xiao; Yao, Dezhong

    2008-12-01

    How to localize the neural electric activities within brain effectively and precisely from the scalp electroencephalogram (EEG) recordings is a critical issue for current study in clinical neurology and cognitive neuroscience. In this paper, based on the charge source model and the iterative re-weighted strategy, proposed is a new maximum neighbor weight based iterative sparse source imaging method, termed as CMOSS (Charge source model based Maximum neighbOr weight Sparse Solution). Different from the weight used in focal underdetermined system solver (FOCUSS) where the weight for each point in the discrete solution space is independently updated in iterations, the new designed weight for each point in each iteration is determined by the source solution of the last iteration at both the point and its neighbors. Using such a new weight, the next iteration may have a bigger chance to rectify the local source location bias existed in the previous iteration solution. The simulation studies with comparison to FOCUSS and LORETA for various source configurations were conducted on a realistic 3-shell head model, and the results confirmed the validation of CMOSS for sparse EEG source localization. Finally, CMOSS was applied to localize sources elicited in a visual stimuli experiment, and the result was consistent with those source areas involved in visual processing reported in previous studies.

  3. Classification of EEG Signals using adaptive weighted distance nearest neighbor algorithm

    Directory of Open Access Journals (Sweden)

    E. Parvinnia

    2014-01-01

    Full Text Available Electroencephalogram (EEG signals are often used to diagnose diseases such as seizure, alzheimer, and schizophrenia. One main problem with the recorded EEG samples is that they are not equally reliable due to the artifacts at the time of recording. EEG signal classification algorithms should have a mechanism to handle this issue. It seems that using adaptive classifiers can be useful for the biological signals such as EEG. In this paper, a general adaptive method named weighted distance nearest neighbor (WDNN is applied for EEG signal classification to tackle this problem. This classification algorithm assigns a weight to each training sample to control its influence in classifying test samples. The weights of training samples are used to find the nearest neighbor of an input query pattern. To assess the performance of this scheme, EEG signals of thirteen schizophrenic patients and eighteen normal subjects are analyzed for the classification of these two groups. Several features including, fractal dimension, band power and autoregressive (AR model are extracted from EEG signals. The classification results are evaluated using Leave one (subject out cross validation for reliable estimation. The results indicate that combination of WDNN and selected features can significantly outperform the basic nearest-neighbor and the other methods proposed in the past for the classification of these two groups. Therefore, this method can be a complementary tool for specialists to distinguish schizophrenia disorder.

  4. Local and neighboring patch conditions alter sex-specific movement in banana weevils.

    Science.gov (United States)

    Carval, Dominique; Perrin, Benjamin; Duyck, Pierre-François; Tixier, Philippe

    2015-12-01

    Understanding the mechanisms underlying the movements and spread of a species over time and space is a major concern of ecology. Here, we assessed the effects of an individual's sex and the density and sex ratio of conspecifics in the local and neighboring environment on the movement probability of the banana weevil, Cosmopolites sordidus. In a "two patches" experiment, we used radiofrequency identification tags to study the C. sordidus movement response to patch conditions. We showed that local and neighboring densities of conspecifics affect the movement rates of individuals but that the density-dependent effect can be either positive or negative depending on the relative densities of conspecifics in local and neighboring patches. We demonstrated that sex ratio also influences the movement of C. sordidus, that is, the weevil exhibits nonfixed sex-biased movement strategies. Sex-biased movement may be the consequence of intrasexual competition for resources (i.e., oviposition sites) in females and for mates in males. We also detected a high individual variability in the propensity to move. Finally, we discuss the role of demographic stochasticity, sex-biased movement, and individual heterogeneity in movement on the colonization process.

  5. A Novel AMR-WB Speech Steganography Based on Diameter-Neighbor Codebook Partition

    Directory of Open Access Journals (Sweden)

    Junhui He

    2018-01-01

    Full Text Available Steganography is a means of covert communication without revealing the occurrence and the real purpose of communication. The adaptive multirate wideband (AMR-WB is a widely adapted format in mobile handsets and is also the recommended speech codec for VoLTE. In this paper, a novel AMR-WB speech steganography is proposed based on diameter-neighbor codebook partition algorithm. Different embedding capacity may be achieved by adjusting the iterative parameters during codebook division. The experimental results prove that the presented AMR-WB steganography may provide higher and flexible embedding capacity without inducing perceptible distortion compared with the state-of-the-art methods. With 48 iterations of cluster merging, twice the embedding capacity of complementary-neighbor-vertices-based embedding method may be obtained with a decrease of only around 2% in speech quality and much the same undetectability. Moreover, both the quality of stego speech and the security regarding statistical steganalysis are better than the recent speech steganography based on neighbor-index-division codebook partition.

  6. Cultural macroevolution on neighbor graphs : vertical and horizontal transmission among Western North American Indian societies.

    Science.gov (United States)

    Towner, Mary C; Grote, Mark N; Venti, Jay; Borgerhoff Mulder, Monique

    2012-09-01

    What are the driving forces of cultural macroevolution, the evolution of cultural traits that characterize societies or populations? This question has engaged anthropologists for more than a century, with little consensus regarding the answer. We develop and fit autologistic models, built upon both spatial and linguistic neighbor graphs, for 44 cultural traits of 172 societies in the Western North American Indian (WNAI) database. For each trait, we compare models including or excluding one or both neighbor graphs, and for the majority of traits we find strong evidence in favor of a model which uses both spatial and linguistic neighbors to predict a trait's distribution. Our results run counter to the assertion that cultural trait distributions can be explained largely by the transmission of traits from parent to daughter populations and are thus best analyzed with phylogenies. In contrast, we show that vertical and horizontal transmission pathways can be incorporated in a single model, that both transmission modes may indeed operate on the same trait, and that for most traits in the WNAI database, accounting for only one mode of transmission would result in a loss of information.

  7. Protein function prediction using neighbor relativity in protein-protein interaction network.

    Science.gov (United States)

    Moosavi, Sobhan; Rahgozar, Masoud; Rahimi, Amir

    2013-04-01

    There is a large gap between the number of discovered proteins and the number of functionally annotated ones. Due to the high cost of determining protein function by wet-lab research, function prediction has become a major task for computational biology and bioinformatics. Some researches utilize the proteins interaction information to predict function for un-annotated proteins. In this paper, we propose a novel approach called "Neighbor Relativity Coefficient" (NRC) based on interaction network topology which estimates the functional similarity between two proteins. NRC is calculated for each pair of proteins based on their graph-based features including distance, common neighbors and the number of paths between them. In order to ascribe function to an un-annotated protein, NRC estimates a weight for each neighbor to transfer its annotation to the unknown protein. Finally, the unknown protein will be annotated by the top score transferred functions. We also investigate the effect of using different coefficients for various types of functions. The proposed method has been evaluated on Saccharomyces cerevisiae and Homo sapiens interaction networks. The performance analysis demonstrates that NRC yields better results in comparison with previous protein function prediction approaches that utilize interaction network. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. A new approach to very short term wind speed prediction using k-nearest neighbor classification

    International Nuclear Information System (INIS)

    Yesilbudak, Mehmet; Sagiroglu, Seref; Colak, Ilhami

    2013-01-01

    Highlights: ► Wind speed parameter was predicted in an n-tupled inputs using k-NN classification. ► The effects of input parameters, nearest neighbors and distance metrics were analyzed. ► Many useful and reasonable inferences were uncovered using the developed model. - Abstract: Wind energy is an inexhaustible energy source and wind power production has been growing rapidly in recent years. However, wind power has a non-schedulable nature due to wind speed variations. Hence, wind speed prediction is an indispensable requirement for power system operators. This paper predicts wind speed parameter in an n-tupled inputs using k-nearest neighbor (k-NN) classification and analyzes the effects of input parameters, nearest neighbors and distance metrics on wind speed prediction. The k-NN classification model was developed using the object oriented programming techniques and includes Manhattan and Minkowski distance metrics except from Euclidean distance metric on the contrary of literature. The k-NN classification model which uses wind direction, air temperature, atmospheric pressure and relative humidity parameters in a 4-tupled space achieved the best wind speed prediction for k = 5 in the Manhattan distance metric. Differently, the k-NN classification model which uses wind direction, air temperature and atmospheric pressure parameters in a 3-tupled inputs gave the worst wind speed prediction for k = 1 in the Minkowski distance metric

  9. The LHCb Silicon Tracker

    CERN Document Server

    Elsasser, Ch; Gallas Torreira, A; Pérez Trigo, A; Rodríguez Pérez, P; Bay, A; Blanc, F; Dupertuis, F; Haefeli, G; Komarov, I; Märki, R; Muster, B; Nakada, T; Schneider, O; Tobin, M; Tran, M T; Anderson, J; Bursche, A; Chiapolini, N; Saornil, S; Steiner, S; Steinkamp, O; Straumann, U; Vollhardt, A; Britsch, M; Schmelling, M; Voss, H; Okhrimenko, O; Pugatch, V

    2013-01-01

    The aim of the LHCb experiment is to study rare heavy quark decays and CP vio- lation with the high rate of beauty and charmed hadrons produced in $pp$ collisions at the LHC. The detector is designed as a single-arm forward spectrometer with excellent tracking and particle identification performance. The Silicon Tracker is a key part of the tracking system to measure the particle trajectories to high precision. This paper reports the performance as well as the results of the radiation damage monitoring based on leakage currents and on charge collection efficiency scans during the data taking in the LHC Run I.

  10. Photovoltaics: sunshine and silicon

    Energy Technology Data Exchange (ETDEWEB)

    Stirzaker, Mike

    2006-05-15

    Spain's photovoltaic sector grew rapidly in 2004 only to slow down in 2005. While a State-guaranteed feed-in tariff is in place to drive a take-off, some of the smaller administrative cogs are buckling under the pressure. Projects are being further slowed by soaring world silicon prices and module shortages. Nevertheless, market volume is higher than ever before, and bio capital from both home and abroad is betting that the Spanish take-off is around the corner. (Author)

  11. Magnetically retained silicone facial prosthesis

    African Journals Online (AJOL)

    2013-06-09

    Jun 9, 2013 ... Prosthetic camouflaging of facial defects and use of silicone maxillofacial material are the alternatives to the surgical retreatment. Silicone elastomers provide more options to clinician for customization of the facial prosthesis which is simple, esthetically good when coupled with bio magnets for retention.

  12. Impurity doping processes in silicon

    CERN Document Server

    Wang, FFY

    1981-01-01

    This book introduces to non-experts several important processes of impurity doping in silicon and goes on to discuss the methods of determination of the concentration of dopants in silicon. The conventional method used is the discussion process, but, since it has been sufficiently covered in many texts, this work describes the double-diffusion method.

  13. Radiation hard cryogenic silicon detectors

    International Nuclear Information System (INIS)

    Casagrande, L.; Abreu, M.C.; Bell, W.H.; Berglund, P.; Boer, W. de; Borchi, E.; Borer, K.; Bruzzi, M.; Buontempo, S.; Chapuy, S.; Cindro, V.; Collins, P.; D'Ambrosio, N.; Da Via, C.; Devine, S.; Dezillie, B.; Dimcovski, Z.; Eremin, V.; Esposito, A.; Granata, V.; Grigoriev, E.; Hauler, F.; Heijne, E.; Heising, S.; Janos, S.; Jungermann, L.; Konorov, I.; Li, Z.; Lourenco, C.; Mikuz, M.; Niinikoski, T.O.; O'Shea, V.; Pagano, S.; Palmieuri, V.G.; Paul, S.; Pirollo, S.; Pretzl, K.; Rato, P.; Ruggiero, G.; Smith, K.; Sonderegger, P.; Sousa, P.; Verbitskaya, E.; Watts, S.; Zavrtanik, M.

    2002-01-01

    It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, 'resuscitate' when operated at temperatures below 130 K. This is often referred to as the 'Lazarus effect'. The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors

  14. Recent developments in silicon calorimetry

    International Nuclear Information System (INIS)

    Brau, J.E.

    1990-11-01

    We present a survey of some of the recent calorimeter applications of silicon detectors. The numerous attractive features of silicon detectors are summarized, with an emphasis on those aspects important to calorimetry. Several of the uses of this technology are summarized and referenced. We consider applications for electromagnetic calorimetry, hadronic calorimetry, and proposals for the SSC

  15. Amorphous silicon ionizing particle detectors

    Science.gov (United States)

    Street, Robert A.; Mendez, Victor P.; Kaplan, Selig N.

    1988-01-01

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation.

  16. Flowmeter with silicon flow tube

    NARCIS (Netherlands)

    Lammerink, Theodorus S.J.; Dijkstra, Marcel; Haneveld, J.; Lötters, Joost Conrad

    2009-01-01

    A flowmeter comprising a system chip with a silicon substrate provided on a carrier, in an opening whereof at least one silicon flow tube is provided for transporting a medium whose flow rate is to be measured, said tube having two ends that issue via a wall of the opening into channels coated with

  17. Luneburg lens in silicon photonics.

    Science.gov (United States)

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-03-14

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms.

  18. Silicon-micromachined microchannel plates

    CERN Document Server

    Beetz, C P; Steinbeck, J; Lemieux, B; Winn, D R

    2000-01-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of approx 0.5 to approx 25 mu m, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposite...

  19. Flexible silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Blakers, A.W.; Armour, T. [Centre for Sustainable Energy Systems, The Australian National University, Canberra ACT 0200 (Australia)

    2009-08-15

    In order to be useful for certain niche applications, crystalline silicon solar cells must be able to sustain either one-time flexure or multiple non-critical flexures without significant loss of strength or efficiency. This paper describes experimental characterisation of the behaviour of thin crystalline silicon solar cells, under either static or repeated flexure, by flexing samples and recording any resulting changes in performance. Thin SLIVER cells were used for the experiment. Mechanical strength was found to be unaffected after 100,000 flexures. Solar conversion efficiency remained at greater than 95% of the initial value after 100,000 flexures. Prolonged one-time flexure close to, but not below, the fracture radius resulted in no significant change of properties. For every sample, fracture occurred either on the first flexure to a given radius of curvature, or not at all when using that radius. In summary, for a given radius of curvature, either the flexed solar cells broke immediately, or they were essentially unaffected by prolonged or multiple flexing. (author)

  20. ATLAS Silicon Microstrip Tracker

    CERN Document Server

    Haefner, Petra; The ATLAS collaboration

    2010-01-01

    The SemiConductor Tracker (SCT), made up from silicon micro-strip detectors is the key precision tracking device in ATLAS, one of the experiments at CERN LHC. The completed SCT is in very good shape: 99.3% of the SCT strips are operational, noise occupancy and hit efficiency exceed the design specifications. In the talk the current status of the SCT will be reviewed. We will report on the operation of the detector and observed problems, with stress on the sensor and electronics performance. TWEPP Summary In December 2009 the ATLAS experiment at the CERN Large Hadron Collider (LHC) recorded the first proton- proton collisions at a centre-of-mass energy of 900 GeV and this was followed by the unprecedented energy of 7 TeV in March 2010. The SemiConductor Tracker (SCT) is the key precision tracking device in ATLAS, made up from silicon micro-strip detectors processed in the planar p-in-n technology. The signal from the strips is processed in the front-end ASICS ABCD3TA, working in the binary readout mode. Data i...

  1. Electronic structure of deep levels in silicon. A study of gold, magnesium, and iron centers in silicon

    International Nuclear Information System (INIS)

    Thilderkvist, A. L.

    1994-02-01

    The electronic structure of gold, magnesium and iron related deep centers in silicon is investigated. Their deep and shallow levels are studied by means of fourier transform spectroscopy, combined with uniaxial stress and Zeeman spectroscopy. The neutral substitutional gold center in silicon is investigated and the center is paramagnetic, S=1/2, with g||≅2.8 and g≅0, and has a static distortion. Reorientation between different equivalent distortions is observed even at 1.9 K. A gold pair center in silicon is studied and several line series, with a zero-phonon line followed by several phonon replicas, are observed. Uniaxial stress and Zeeman results reveal a trigonal symmetry of the center, which together with the high dissociation energy of 1.7 eV suggests that the center consists of two nearest-neighbor substitutional gold atoms. A divacancy model is employed to explain the electronic properties of the center. The interstitial magnesium double donor in silicon in its two charge states Mg o and Mg + is investigated. Deviations in the binding energies of the excited states from those calculated within the effective-mass theory (EMT) are found and explained by a perturbation in the central-cell region. The quadratic Zeeman effect of shallow donors in silicon is analyzed within the framework of the EMT using a numerical approach. The wave functions are calculated in a discrete radial mesh and the Zeeman Hamiltonian has be evaluated for the lowest excited states for fields up to 6 T. The neutral interstitial iron defect in silicon gives rise to two sets of line spectra. The first set arises when an electron is excited to a shallow donor like state where the electron is decoupled from the Fe + core which has a 4 T 1 ground state term. The second set arises when an excited electron of a 1 symmetry is coupled by exchange interaction to the core, yielding at 5 T 1 final state. Experiments determine the multiplet splitting of the 4 T 1 and 5 T 1 states due to spring

  2. Belowground neighbor perception in Arabidopsis thaliana studied by transcriptome analysis: roots of Hieracium pilosella cause biotic stress

    Directory of Open Access Journals (Sweden)

    Christoph eSchmid

    2013-08-01

    Full Text Available Root-root interactions are much more sophisticated than previously thought, yet the mechanisms of belowground neighbor perception remain largely obscure. Genome-wide transcriptome analyses allow detailed insight into plant reactions to environmental cues.A root interaction trial was set up to explore both morphological and whole genome transcriptional responses in roots of Arabidopsis thaliana in the presence or absence of an inferior competitor, Hieracium pilosella.Neighbor perception was indicated by Arabidopsis roots predominantly growing away from the neighbor (segregation, while solitary plants placed more roots towards the middle of the pot. Total biomass remained unaffected. Database comparisons in transcriptome analysis revealed considerable similarity between Arabidopsis root reactions to neighbors and reactions to pathogens. Detailed analyses of the functional category ‘biotic stress’ using MapMan tools found the sub-category ‘pathogenesis-related proteins’ highly significantly induced. A comparison to a study on intraspecific competition brought forward a core of genes consistently involved in reactions to neighbor roots.We conclude that beyond resource depletion roots perceive neighboring roots or their associated microorganisms by a relatively uniform mechanism that involves the strong induction of pathogenesis-related proteins. In an ecological context the findings reveal that belowground neighbor detection may occur independently of resource depletion, allowing for a time advantage for the root to prepare for potential interactions.

  3. Relationship between silicon concentration and creatinine clearance

    International Nuclear Information System (INIS)

    Miura, Y.; Nakai, K.; Itoh, C.; Horikiri, J.; Sera, K.; Sato, M.

    1998-01-01

    Silicon levels in dialysis patients are markedly increasing. Using PIXE we determined the relationship between silicon concentration and creatinine clearance in 30 samples. Urine silicon concentration were significantly correlated to creatinine clearance (p<0.001). And also serum silicon concentration were significantly correlated to creatinine clearance (p<0.0001). (author)

  4. Luminescence of porous silicon doped by erbium

    International Nuclear Information System (INIS)

    Bondarenko, V.P.; Vorozov, N.N.; Dolgij, L.N.; Dorofeev, A.M.; Kazyuchits, N.M.; Leshok, A.A.; Troyanova, G.N.

    1996-01-01

    The possibility of the 1.54 μm intensive luminescence in the silicon dense porous layers, doped by erbium, with various structures is shown. Low-porous materials of both porous type on the p-type silicon and porous silicon with wood-like structure on the n + type silicon may be used for formation of light-emitting structures

  5. Apparatus for making molten silicon

    Science.gov (United States)

    Levin, Harry (Inventor)

    1988-01-01

    A reactor apparatus (10) adapted for continuously producing molten, solar grade purity elemental silicon by thermal reaction of a suitable precursor gas, such as silane (SiH.sub.4), is disclosed. The reactor apparatus (10) includes an elongated reactor body (32) having graphite or carbon walls which are heated to a temperature exceeding the melting temperature of silicon. The precursor gas enters the reactor body (32) through an efficiently cooled inlet tube assembly (22) and a relatively thin carbon or graphite septum (44). The septum (44), being in contact on one side with the cooled inlet (22) and the heated interior of the reactor (32) on the other side, provides a sharp temperature gradient for the precursor gas entering the reactor (32) and renders the operation of the inlet tube assembly (22) substantially free of clogging. The precursor gas flows in the reactor (32) in a substantially smooth, substantially axial manner. Liquid silicon formed in the initial stages of the thermal reaction reacts with the graphite or carbon walls to provide a silicon carbide coating on the walls. The silicon carbide coated reactor is highly adapted for prolonged use for production of highly pure solar grade silicon. Liquid silicon (20) produced in the reactor apparatus (10) may be used directly in a Czochralski or other crystal shaping equipment.

  6. Silicon Telescope Detectors

    CERN Document Server

    Gurov, Yu B; Sandukovsky, V G; Yurkovski, J

    2005-01-01

    The results of research and development of special silicon detectors with a large active area ($> 8 cm^{2}$) for multilayer telescope spectrometers (fulfilled in the Laboratory of Nuclear Problems, JINR) are reviewed. The detector parameters are listed. The production of totally depleted surface barrier detectors (identifiers) operating under bias voltage two to three times higher than depletion voltage is described. The possibility of fabrication of lithium drifted counters with a very thin entrance window on the diffusion side of the detector (about 10--20 $\\mu$m) is shown. The detector fabrication technique has allowed minimizing detector dead regions without degradation of their spectroscopic characteristics and reliability during long time operation in charge particle beams.

  7. Silicon radiation detector

    International Nuclear Information System (INIS)

    Benc, I.; Kerhart, J.; Kopecky, J.; Krca, P.; Veverka, V.; Weidner, M.; Weinova, H.

    1992-01-01

    The silicon radiation detector, which is designed for the detection of electrons with energies above 500 eV and of radiation within the region of 200 to 1100 nm, comprises a PIN or PNN + type photodiode. The active acceptor photodiode is formed by a detector surface of shallow acceptor diffusion surrounded by a collector band of deep acceptor diffusion. The detector surface of shallow P-type diffusion with an acceptor concentration of 10 15 to 10 17 atoms/cm 3 reaches a depth of 40 to 100 nm. One sixth to one eighth of the collector band width is overlapped by the P + collector band at a width of 150 to 300 μm with an acceptor concentration of 10 20 to 10 21 atoms/cm 3 down a depth of 0.5 to 3 μm. This band is covered with a conductive layer, of NiCr for instance. (Z.S.)

  8. Zirconates heteroepitaxy on silicon

    Science.gov (United States)

    Fompeyrine, Jean; Seo, Jin Won; Seigwart, Heinz; Rossel, Christophe; Locquet, Jean-Pierre

    2002-03-01

    In the coming years, agressive scaling in CMOS technology will probably trigger the transition to more advanced materials, for example alternate gate dielectrics. Epitaxial thin films are attractive candidates, as long as the difficult chemical and structural issues can be solved, and superior properties can be obtained. Since very few binary oxides can match the electrical, physical and structural requirements which are needed, a combination of those binaries are used here to investigate other lattice matched oxides. We will report on the growth of crystalline zirconium oxide thin films stabilized with different cationic substitutions. All films have been grown in an oxide-MBE system by direct evaporation of the elements on silicon substrates and exposure to molecular or atomic oxygen. The conditions required to obtain epitaxial thin films will be discussed, and successful examples will be presented.

  9. Silicon in cereal straw

    DEFF Research Database (Denmark)

    Murozuka, Emiko

    Silicon (Si) is known to be a beneficial element for plants. However, when plant residues are to be used as feedstock for second generation bioenergy, Si may reduce the suitability of the biomass for biochemical or thermal conversion technologies. The objective of this PhD study was to investigate......, a mutant in Si influx transporter BdLsi1 was identified. BdLsi1 belongs to the major intrinsic protein family. The mutant BdLsi1 protein had an amino acid change from proline to serine in the highly conserved NPA motif. The mutation caused a defect in channeling of Si as well as other substrates...... such as germanium and arsenite. The Si concentration in the mutant plant was significantly reduced by more than 80 %. Rice mutants defective in Si transporters OsLsi1 and OsLsi2 also showed significantly lower straw Si concentration. It is concluded that the quality of straw biomass for bioenergy purposes can...

  10. Formation of porous silicon oxide from substrate-bound silicon rich silicon oxide layers by continuous-wave laser irradiation

    Science.gov (United States)

    Wang, Nan; Fricke-Begemann, Th.; Peretzki, P.; Ihlemann, J.; Seibt, M.

    2018-03-01

    Silicon nanocrystals embedded in silicon oxide that show room temperature photoluminescence (PL) have great potential in silicon light emission applications. Nanocrystalline silicon particle formation by laser irradiation has the unique advantage of spatially controlled heating, which is compatible with modern silicon micro-fabrication technology. In this paper, we employ continuous wave laser irradiation to decompose substrate-bound silicon-rich silicon oxide films into crystalline silicon particles and silicon dioxide. The resulting microstructure is studied using transmission electron microscopy techniques with considerable emphasis on the formation and properties of laser damaged regions which typically quench room temperature PL from the nanoparticles. It is shown that such regions consist of an amorphous matrix with a composition similar to silicon dioxide which contains some nanometric silicon particles in addition to pores. A mechanism referred to as "selective silicon ablation" is proposed which consistently explains the experimental observations. Implications for the damage-free laser decomposition of silicon-rich silicon oxides and also for controlled production of porous silicon dioxide films are discussed.

  11. Muonium states in silicon carbide

    International Nuclear Information System (INIS)

    Patterson, B.D.; Baumeler, H.; Keller, H.; Kiefl, R.F.; Kuendig, W.; Odermatt, W.; Schneider, J.W.; Estle, T.L.; Spencer, D.P.; Savic, I.M.

    1986-01-01

    Implanted muons in samples of silicon carbide have been observed to form paramagnetic muonium centers (μ + e - ). Muonium precession signals in low applied magnetic fields have been observed at 22 K in a granular sample of cubic β-SiC, however it was not possible to determine the hyperfine frequency. In a signal crystal sample of hexagonal 6H-SiC, three apparently isotropic muonium states were observed at 20 K and two at 300 K, all with hyperfine frequencies intermediate between those of the isotropic muonium centers in diamond and silicon. No evidence was seen of an anisotropic muonium state analogous to the Mu * state in diamond and silicon. (orig.)

  12. Characterization of Czochralski silicon detectors

    OpenAIRE

    Luukka, Panja-Riina

    2006-01-01

    This thesis describes the characterization of irradiated and non-irradiated segmented detectors made of high-resistivity (>1 kΩcm) magnetic Czochralski (MCZ) silicon. It is shown that the radiation hardness (RH) of the protons of these detectors is higher than that of devices made of traditional materials such as Float Zone (FZ) silicon or Diffusion Oxygenated Float Zone (DOFZ) silicon due to the presence of intrinsic oxygen (> 5 × 1017 cm−3). The MCZ devices therefore present an interesting ...

  13. Adaptive behavior of neighboring neurons during adaptation-induced plasticity of orientation tuning in V1

    Directory of Open Access Journals (Sweden)

    Shumikhina Svetlana

    2009-12-01

    Full Text Available Abstract Background Sensory neurons display transient changes of their response properties following prolonged exposure to an appropriate stimulus (adaptation. In adult cat primary visual cortex, orientation-selective neurons shift their preferred orientation after being adapted to a non-preferred orientation. The direction of those shifts, towards (attractive or away (repulsive from the adapter depends mostly on adaptation duration. How the adaptive behavior of a neuron is related to that of its neighbors remains unclear. Results Here we show that in most cases (75%, cells shift their preferred orientation in the same direction as their neighbors. We also found that cells shifting preferred orientation differently from their neighbors (25% display three interesting properties: (i larger variance of absolute shift amplitude, (ii wider tuning bandwidth and (iii larger range of preferred orientations among the cluster of cells. Several response properties of V1 neurons depend on their location within the cortical orientation map. Our results suggest that recording sites with both attractive and repulsive shifts following adaptation may be located in close proximity to iso-orientation domain boundaries or pinwheel centers. Indeed, those regions have a more diverse orientation distribution of local inputs that could account for the three properties above. On the other hand, sites with all cells shifting their preferred orientation in the same direction could be located within iso-orientation domains. Conclusions Our results suggest that the direction and amplitude of orientation preference shifts in V1 depend on location within the orientation map. This anisotropy of adaptation-induced plasticity, comparable to that of the visual cortex itself, could have important implications for our understanding of visual adaptation at the psychophysical level.

  14. A γ dose distribution evaluation technique using the k-d tree for nearest neighbor searching

    International Nuclear Information System (INIS)

    Yuan Jiankui; Chen Weimin

    2010-01-01

    Purpose: The authors propose an algorithm based on the k-d tree for nearest neighbor searching to improve the γ calculation time for 2D and 3D dose distributions. Methods: The γ calculation method has been widely used for comparisons of dose distributions in clinical treatment plans and quality assurances. By specifying the acceptable dose and distance-to-agreement criteria, the method provides quantitative measurement of the agreement between the reference and evaluation dose distributions. The γ value indicates the acceptability. In regions where γ≤1, the predefined criterion is satisfied and thus the agreement is acceptable; otherwise, the agreement fails. Although the concept of the method is not complicated and a quick naieve implementation is straightforward, an efficient and robust implementation is not trivial. Recent algorithms based on exhaustive searching within a maximum radius, the geometric Euclidean distance, and the table lookup method have been proposed to improve the computational time for multidimensional dose distributions. Motivated by the fact that the least searching time for finding a nearest neighbor can be an O(log N) operation with a k-d tree, where N is the total number of the dose points, the authors propose an algorithm based on the k-d tree for the γ evaluation in this work. Results: In the experiment, the authors found that the average k-d tree construction time per reference point is O(log N), while the nearest neighbor searching time per evaluation point is proportional to O(N 1/k ), where k is between 2 and 3 for two-dimensional and three-dimensional dose distributions, respectively. Conclusions: Comparing with other algorithms such as exhaustive search and sorted list O(N), the k-d tree algorithm for γ evaluation is much more efficient.

  15. Tricriticality in the q-neighbor Ising model on a partially duplex clique.

    Science.gov (United States)

    Chmiel, Anna; Sienkiewicz, Julian; Sznajd-Weron, Katarzyna

    2017-12-01

    We analyze a modified kinetic Ising model, a so-called q-neighbor Ising model, with Metropolis dynamics [Phys. Rev. E 92, 052105 (2015)PLEEE81539-375510.1103/PhysRevE.92.052105] on a duplex clique and a partially duplex clique. In the q-neighbor Ising model each spin interacts only with q spins randomly chosen from its whole neighborhood. In the case of a duplex clique the change of a spin is allowed only if both levels simultaneously induce this change. Due to the mean-field-like nature of the model we are able to derive the analytic form of transition probabilities and solve the corresponding master equation. The existence of the second level changes dramatically the character of the phase transition. In the case of the monoplex clique, the q-neighbor Ising model exhibits a continuous phase transition for q=3, discontinuous phase transition for q≥4, and for q=1 and q=2 the phase transition is not observed. On the other hand, in the case of the duplex clique continuous phase transitions are observed for all values of q, even for q=1 and q=2. Subsequently we introduce a partially duplex clique, parametrized by r∈[0,1], which allows us to tune the network from monoplex (r=0) to duplex (r=1). Such a generalized topology, in which a fraction r of all nodes appear on both levels, allows us to obtain the critical value of r=r^{*}(q) at which a tricriticality (switch from continuous to discontinuous phase transition) appears.

  16. Polycrystalline Silicon Gettered by Porous Silicon and Heavy Phosphorous Diffusion

    Institute of Scientific and Technical Information of China (English)

    LIU Zuming(刘祖明); Souleymane K Traore; ZHANG Zhongwen(张忠文); LUO Yi(罗毅)

    2004-01-01

    The biggest barrier for photovoltaic (PV) utilization is its high cost, so the key for scale PV utilization is to further decrease the cost of solar cells. One way to improve the efficiency, and therefore lower the cost, is to increase the minority carrier lifetime by controlling the material defects. The main defects in grain boundaries of polycrystalline silicon gettered by porous silicon and heavy phosphorous diffusion have been studied. The porous silicon was formed on the two surfaces of wafers by chemical etching. Phosphorous was then diffused into the wafers at high temperature (900℃). After the porous silicon and diffusion layers were removed, the minority carrier lifetime was measured by photo-conductor decay. The results show that the lifetime's minority carriers are increased greatly after such treatment.

  17. A method of neighbor classes based SVM classification for optical printed Chinese character recognition.

    Science.gov (United States)

    Zhang, Jie; Wu, Xiaohong; Yu, Yanmei; Luo, Daisheng

    2013-01-01

    In optical printed Chinese character recognition (OPCCR), many classifiers have been proposed for the recognition. Among the classifiers, support vector machine (SVM) might be the best classifier. However, SVM is a classifier for two classes. When it is used for multi-classes in OPCCR, its computation is time-consuming. Thus, we propose a neighbor classes based SVM (NC-SVM) to reduce the computation consumption of SVM. Experiments of NC-SVM classification for OPCCR have been done. The results of the experiments have shown that the NC-SVM we proposed can effectively reduce the computation time in OPCCR.

  18. Penerapan Metode K-nearest Neighbor pada Penentuan Grade Dealer Sepeda Motor

    OpenAIRE

    Leidiyana, Henny

    2017-01-01

    The mutually beneficial cooperation is a very important thing for a leasing and dealer. Incentives for marketing is given in order to get consumers as much as possible. But sometimes the surveyor objectivity is lost due to the conspiracy on the field of marketing and surveyors. To overcome this, leasing a variety of ways one of them is doing ranking against the dealer. In this study the application of the k-Nearest Neighbor method and Euclidean distance measurement to determine the grade deal...

  19. Fast and Accuracy Control Chart Pattern Recognition using a New cluster-k-Nearest Neighbor

    OpenAIRE

    Samir Brahim Belhaouari

    2009-01-01

    By taking advantage of both k-NN which is highly accurate and K-means cluster which is able to reduce the time of classification, we can introduce Cluster-k-Nearest Neighbor as "variable k"-NN dealing with the centroid or mean point of all subclasses generated by clustering algorithm. In general the algorithm of K-means cluster is not stable, in term of accuracy, for that reason we develop another algorithm for clustering our space which gives a higher accuracy than K-means cluster, less ...

  20. Tuberculosis control in Bolivia, Chile, Colombia and Peru: why does incidence vary so much between neighbors?

    Science.gov (United States)

    Sobero, R A; Peabody, J W

    2006-11-01

    In 2003, Peru and Bolivia reported the highest annual tuberculosis (TB) incidence rates in the Americas. Neighboring Colombia and Chile had lower annual incidence rates despite their proximity. To determine what factors contribute to differences in TB incidence rates among Chile, Colombia, Bolivia and Peru. Multiple sources of literature dating between 1990 and 2005 were used and World Health Organization TB control guidelines were consulted for policy level comparisons. Comprehensive implementation of the DOTS strategy is the main factor explaining the differences in TB incidence rates, even after considering socio-economic factors. Cross-national comparisons suggest ways to improve regional DOTS implementation.

  1. Neighbor-directed histidine N(τ) alkylation. A route to imidazolium-containing phosphopeptide macrocycles

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Wen-Jian [National Cancer Inst., Frederick, MD (United States); Park, Jung-Eun [National Cancer Inst., Bethesda, MD (United States); Grant, Robert [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lai, Christopher C. [National Cancer Inst., Frederick, MD (United States); Kelley, James A. [National Cancer Inst., Frederick, MD (United States); Yaffe, Michael B. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lee, Kyung S. [National Cancer Inst., Bethesda, MD (United States); Burke, Terrence R. [National Cancer Inst., Frederick, MD (United States)

    2015-07-07

    Our recently discovered, selective, on-resin route to N(τ)-alkylated imidazolium-containing histidine residues affords new strategies for peptide mimetic design. In this, we demonstrate the use of this chemistry to prepare a series of macrocyclic phosphopeptides, in which imidazolium groups serve as ring-forming junctions. These cationic moieties subsequently serve to charge-mask the phosphoamino acid group that directed their formation. Furthermore, neighbor-directed histidine N(τ)-alkylation opens the door to new families of phosphopeptidomimetics for use in a range of chemical biology contexts.

  2. Low-spin identical bands in neighboring odd-A and even-even nuclei

    International Nuclear Information System (INIS)

    Baktash, C.; Winchell, D.F.; Garrett, J.D.; Smith, A.

    1992-01-01

    A comprehensive study of odd-A rotational bands in normally deformed rare-earth nuclei indicates that a large number of seniority-one configurations (21% for odd-Z nuclei) at low spin have moments of inertia nearly identical to that of the seniority-zero configuration of the neighboring even-even nucleus with one less nucleon. It is difficult to reconcile these results with conventional models of nuclear pair correlation, which predict variations of about 15% in the moments of inertia of configurations differing by one unit in seniority

  3. Seismic clusters analysis in Northeastern Italy by the nearest-neighbor approach

    Science.gov (United States)

    Peresan, Antonella; Gentili, Stefania

    2018-01-01

    The main features of earthquake clusters in Northeastern Italy are explored, with the aim to get new insights on local scale patterns of seismicity in the area. The study is based on a systematic analysis of robustly and uniformly detected seismic clusters, which are identified by a statistical method, based on nearest-neighbor distances of events in the space-time-energy domain. The method permits us to highlight and investigate the internal structure of earthquake sequences, and to differentiate the spatial properties of seismicity according to the different topological features of the clusters structure. To analyze seismicity of Northeastern Italy, we use information from local OGS bulletins, compiled at the National Institute of Oceanography and Experimental Geophysics since 1977. A preliminary reappraisal of the earthquake bulletins is carried out and the area of sufficient completeness is outlined. Various techniques are considered to estimate the scaling parameters that characterize earthquakes occurrence in the region, namely the b-value and the fractal dimension of epicenters distribution, required for the application of the nearest-neighbor technique. Specifically, average robust estimates of the parameters of the Unified Scaling Law for Earthquakes, USLE, are assessed for the whole outlined region and are used to compute the nearest-neighbor distances. Clusters identification by the nearest-neighbor method turn out quite reliable and robust with respect to the minimum magnitude cutoff of the input catalog; the identified clusters are well consistent with those obtained from manual aftershocks identification of selected sequences. We demonstrate that the earthquake clusters have distinct preferred geographic locations, and we identify two areas that differ substantially in the examined clustering properties. Specifically, burst-like sequences are associated with the north-western part and swarm-like sequences with the south-eastern part of the study

  4. A Novel Quantum Solution to Privacy-Preserving Nearest Neighbor Query in Location-Based Services

    Science.gov (United States)

    Luo, Zhen-yu; Shi, Run-hua; Xu, Min; Zhang, Shun

    2018-04-01

    We present a cheating-sensitive quantum protocol for Privacy-Preserving Nearest Neighbor Query based on Oblivious Quantum Key Distribution and Quantum Encryption. Compared with the classical related protocols, our proposed protocol has higher security, because the security of our protocol is based on basic physical principles of quantum mechanics, instead of difficulty assumptions. Especially, our protocol takes single photons as quantum resources and only needs to perform single-photon projective measurement. Therefore, it is feasible to implement this protocol with the present technologies.

  5. Chaotic synchronization of nearest-neighbor diffusive coupling Hindmarsh-Rose neural networks in noisy environments

    International Nuclear Information System (INIS)

    Fang Xiaoling; Yu Hongjie; Jiang Zonglai

    2009-01-01

    The chaotic synchronization of Hindmarsh-Rose neural networks linked by a nonlinear coupling function is discussed. The HR neural networks with nearest-neighbor diffusive coupling form are treated as numerical examples. By the construction of a special nonlinear-coupled term, the chaotic system is coupled symmetrically. For three and four neurons network, a certain region of coupling strength corresponding to full synchronization is given, and the effect of network structure and noise position are analyzed. For five and more neurons network, the full synchronization is very difficult to realize. All the results have been proved by the calculation of the maximum conditional Lyapunov exponent.

  6. The Impactof the Kurdish Question on Turkey's Relations with its Middle Eastern neighbors

    OpenAIRE

    Asil, Muhammet Ali

    2013-01-01

    Tezin basılısı İstanbul Şehir Üniversitesi Kütüphanesi'ndedir. This dissertation analyzes the “Kurdish Question” from an International Relations perspective. Focusing on the impact of the Kurdish question on Turkey’s relations in the last decade with its Middle Eastern neighbors, i.e. Iran, Syria, and Iraq, and with the European Union; this study shows how Turkey-Middle East and Turkey-EU relations are shaped differently. In the search for reasons for this difference, Realist and Liberal I...

  7. Low-spin identical bands in neighboring odd-A and even-even nuclei

    International Nuclear Information System (INIS)

    Baktash, C.; Winchell, D.F.; Garrett, J.D.; Smith, A.

    1993-01-01

    A comprehensive study of odd-A rotational bands in normally deformed rare-earth nuclei indicates that a large number of seniority-one configurations (21 % for odd-Z nuclei) at low spin have moments of inertia nearly identical to that of the seniority-zero configuration of the neighboring even-even nucleus with one less nucleon. It is difficult to reconcile these results with conventional models of nuclear pair correlation, which predict variations of about 15% in the moments of inertia of configurations differing by one unit in seniority. (orig.)

  8. Effect of Silicon Nanowire on Crystalline Silicon Solar Cell Characteristics

    OpenAIRE

    Zahra Ostadmahmoodi Do; Tahereh Fanaei Sheikholeslami; Hassan Azarkish

    2016-01-01

    Nanowires (NWs) are recently used in several sensor or actuator devices to improve their ordered characteristics. Silicon nanowire (Si NW) is one of the most attractive one-dimensional nanostructures semiconductors because of its unique electrical and optical properties. In this paper, silicon nanowire (Si NW), is synthesized and characterized for application in photovoltaic device. Si NWs are prepared using wet chemical etching method which is commonly used as a simple and low cost method fo...

  9. Efficiency Enhancement of Silicon Solar Cells by Porous Silicon Technology

    Directory of Open Access Journals (Sweden)

    Eugenijus SHATKOVSKIS

    2012-09-01

    Full Text Available Silicon solar cells produced by a usual technology in p-type, crystalline silicon wafer were investigated. The manufactured solar cells were of total thickness 450 mm, the junction depth was of 0.5 mm – 0.7 mm. Porous silicon technologies were adapted to enhance cell efficiency. The production of porous silicon layer was carried out in HF: ethanol = 1 : 2 volume ratio electrolytes, illuminating by 50 W halogen lamps at the time of processing. The etching current was computer-controlled in the limits of (6 ÷ 14 mA/cm2, etching time was set in the interval of (10 ÷ 20 s. The characteristics and performance of the solar cells samples was carried out illuminating by Xenon 5000 K lamp light. Current-voltage characteristic studies have shown that porous silicon structures produced affect the extent of dark and lighting parameters of the samples. Exactly it affects current-voltage characteristic and serial resistance of the cells. It has shown, the formation of porous silicon structure causes an increase in the electric power created of solar cell. Conversion efficiency increases also respectively to the initial efficiency of cell. Increase of solar cell maximum power in 15 or even more percent is found. The highest increase in power have been observed in the spectral range of Dl @ (450 ÷ 850 nm, where ~ 60 % of the A1.5 spectra solar energy is located. It has been demonstrated that porous silicon technology is effective tool to improve the silicon solar cells performance.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2428

  10. Radiation resistant passivation of silicon solar cells

    International Nuclear Information System (INIS)

    Swanson, R.M.; Gan, J.Y.; Gruenbaum, P.E.

    1991-01-01

    This patent describes a silicon solar cell having improved stability when exposed to concentrated solar radiation. It comprises a body of silicon material having a major surface for receiving radiation, a plurality of p and n conductivity regions in the body for collecting electrons and holes created by impinging radiation, and a passivation layer on the major surface including a first layer of silicon oxide in contact with the body and a polycrystalline silicon layer on the first layer of silicon oxide

  11. Sequence correction of random coil chemical shifts: correlation between neighbor correction factors and changes in the Ramachandran distribution

    DEFF Research Database (Denmark)

    Kjærgaard, Magnus; Poulsen, Flemming Martin

    2011-01-01

    Random coil chemical shifts are necessary for secondary chemical shift analysis, which is the main NMR method for identification of secondary structure in proteins. One of the largest challenges in the determination of random coil chemical shifts is accounting for the effect of neighboring residues....... The contributions from the neighboring residues are typically removed by using neighbor correction factors determined based on each residue's effect on glycine chemical shifts. Due to its unusual conformational freedom, glycine may be particularly unrepresentative for the remaining residue types. In this study, we...... in the conformational ensemble are an important source of neighbor effects in disordered proteins. Glutamine derived random coil chemical shifts and correction factors modestly improve our ability to predict (13)C chemical shifts of intrinsically disordered proteins compared to existing datasets, and may thus improve...

  12. Diagnosis of Diabetes Diseases Using an Artificial Immune Recognition System2 (AIRS2) with Fuzzy K-nearest Neighbor

    OpenAIRE

    CHIKH, Mohamed Amine; SAIDI, Meryem; SETTOUTI, Nesma

    2012-01-01

    The use of expert systems and artificial intelligence techniques in disease diagnosis has been increasing gradually. Artificial Immune Recognition System (AIRS) is one of the methods used in medical classification problems. AIRS2 is a more efficient version of the AIRS algorithm. In this paper, we used a modified AIRS2 called MAIRS2 where we replace the K- nearest neighbors algorithm with the fuzzy K-nearest neighbors to improve the diagnostic accuracy of diabetes diseases. The diabetes disea...

  13. Evanescent field phase shifting in a silicon nitride waveguide using a coupled silicon slab

    DEFF Research Database (Denmark)

    Jensen, Asger Sellerup; Oxenløwe, Leif Katsuo; Green, William M. J.

    2015-01-01

    An approach for electrical modulation of low-loss silicon nitride waveguides is proposed, using a silicon nitride waveguide evanescently loaded with a thin silicon slab. The thermooptic phase-shift characteristics are investigated in a racetrack resonator configuration....

  14. Imprinted silicon-based nanophotonics

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Olsen, Brian Bilenberg; Frandsen, Lars Hagedorn

    2007-01-01

    We demonstrate and optically characterize silicon-on-insulator based nanophotonic devices fabricated by nanoimprint lithography. In our demonstration, we have realized ordinary and topology-optimized photonic crystal waveguide structures. The topology-optimized structures require lateral pattern ...

  15. Ultra-fast silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Sadrozinski, H. F.-W., E-mail: hartmut@scipp.ucsc.edu [Santa Cruz Institute for Particle Physics, UC Santa Cruz, Santa Cruz, CA 95064 (United States); Ely, S.; Fadeyev, V.; Galloway, Z.; Ngo, J.; Parker, C.; Petersen, B.; Seiden, A.; Zatserklyaniy, A. [Santa Cruz Institute for Particle Physics, UC Santa Cruz, Santa Cruz, CA 95064 (United States); Cartiglia, N.; Marchetto, F. [INFN Torino, Torino (Italy); Bruzzi, M.; Mori, R.; Scaringella, M.; Vinattieri, A. [University of Florence, Department of Physics and Astronomy, Sesto Fiorentino, Firenze (Italy)

    2013-12-01

    We propose to develop a fast, thin silicon sensor with gain capable to concurrently measure with high precision the space (∼10 μm) and time (∼10 ps) coordinates of a particle. This will open up new application of silicon detector systems in many fields. Our analysis of detector properties indicates that it is possible to improve the timing characteristics of silicon-based tracking sensors, which already have sufficient position resolution, to achieve four-dimensional high-precision measurements. The basic sensor characteristics and the expected performance are listed, the wide field of applications are mentioned and the required R and D topics are discussed. -- Highlights: •We are proposing thin pixel silicon sensors with 10's of picoseconds time resolution. •Fast charge collection is coupled with internal charge multiplication. •The truly 4-D sensors will revolutionize imaging and particle counting in many applications.

  16. Vibrational modes of porous silicon

    International Nuclear Information System (INIS)

    Sabra, M.; Naddaf, M.

    2012-01-01

    On the basis of theoretical and experimental investigations, the origin of room temperature photoluminescence (PL) from porous silicon is found to related to chemical complexes constituted the surface, in particular, SiHx, SiOx and SiOH groups. Ab initio atomic and molecular electronic structure calculations on select siloxane compounds were used for imitation of infrared (IR) spectra of porous silicon. These are compared to the IR spectra of porous silicon recorded by using Fourier Transform Infrared Spectroscopy (FTIR). In contrast to linear siloxane, the suggested circular siloxane terminated with linear siloxane structure is found to well-imitate the experimental spectra. These results are augmented with EDX (energy dispersive x-ray spectroscopy) measurements, which showed that the increase of SiOx content in porous silicon due to rapid oxidation process results in considerable decrease in PL peak intensity and a blue shift in the peak position. (author)

  17. Silicon pressure transducers: a review

    International Nuclear Information System (INIS)

    Aceves M, M.; Sandoval I, F.

    1994-01-01

    We present a review of the pressure sensors, which use the silicon piezo resistive effect and micro machining technique. Typical pressure sensors, applications, design and other different structures are presented. (Author)

  18. Scattering characteristics from porous silicon

    Directory of Open Access Journals (Sweden)

    R. Sabet-Dariani

    2000-12-01

    Full Text Available   Porous silicon (PS layers come into existance as a result of electrochemical anodization on silicon. Although a great deal of research has been done on the formation and optical properties of this material, the exact mechanism involved is not well-understood yet.   In this article, first, the optical properties of silicon and porous silicon are described. Then, previous research and the proposed models about reflection from PS and the origin of its photoluminescence are reveiwed. The reflecting and scattering, absorption and transmission of light from this material, are then investigated. These experiments include,different methods of PS sample preparation their photoluminescence, reflecting and scattering of light determining different characteristics with respect to Si bulk.

  19. Silicon Solar Cell Turns 50

    Energy Technology Data Exchange (ETDEWEB)

    Perlin, J.

    2004-08-01

    This short brochure describes a milestone in solar (or photovoltaic, PV) research-namely, the 50th anniversary of the invention of the first viable silicon solar cell by three researchers at Bell Laboratories.

  20. Method of forming buried oxide layers in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2000-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  1. Silicone nanocomposite coatings for fabrics

    Science.gov (United States)

    Eberts, Kenneth (Inventor); Lee, Stein S. (Inventor); Singhal, Amit (Inventor); Ou, Runqing (Inventor)

    2011-01-01

    A silicone based coating for fabrics utilizing dual nanocomposite fillers providing enhanced mechanical and thermal properties to the silicone base. The first filler includes nanoclusters of polydimethylsiloxane (PDMS) and a metal oxide and a second filler of exfoliated clay nanoparticles. The coating is particularly suitable for inflatable fabrics used in several space, military, and consumer applications, including airbags, parachutes, rafts, boat sails, and inflatable shelters.

  2. Quasimetallic silicon micromachined photonic crystals

    International Nuclear Information System (INIS)

    Temelkuran, B.; Bayindir, Mehmet; Ozbay, E.; Kavanaugh, J. P.; Sigalas, M. M.; Tuttle, G.

    2001-01-01

    We report on fabrication of a layer-by-layer photonic crystal using highly doped silicon wafers processed by semiconductor micromachining techniques. The crystals, built using (100) silicon wafers, resulted in an upper stop band edge at 100 GHz. The transmission and defect characteristics of these structures were found to be analogous to metallic photonic crystals. We also investigated the effect of doping concentration on the defect characteristics. The experimental results agree well with predictions of the transfer matrix method simulations

  3. Industrial Silicon Wafer Solar Cells

    OpenAIRE

    Neuhaus, Dirk-Holger; Münzer, Adolf

    2007-01-01

    In 2006, around 86% of all wafer-based silicon solar cells were produced using screen printing to form the silver front and aluminium rear contacts and chemical vapour deposition to grow silicon nitride as the antireflection coating onto the front surface. This paper reviews this dominant solar cell technology looking into state-of-the-art equipment and corresponding processes for each process step. The main efficiency losses of this type of solar cell are analyzed to demonstrate the future e...

  4. Silicon nanowires: structure and properties

    International Nuclear Information System (INIS)

    Nezhdanov, A.V.; Mashin, A.I.; Razuvaev, A.G.; Ershov, A.V.; Ignatov, S.K.

    2006-01-01

    An attempt to grow silicon nanowires has been made by electron beam evaporation on highly oriented pyrolytic substrate. Needle-like objects are located along the normal to a substrate (density 2 x 10 11 cm -2 ). For modeling quasi-one-dimensional objects calculations of nuclear structure and energy spectra have been accomplished. A fullerene-like structure Si 24 is proposed as a basic atomic configuration of silicon nanowires [ru

  5. Laser tests of silicon detectors

    International Nuclear Information System (INIS)

    Dolezal, Zdenek; Escobar, Carlos; Gadomski, Szymon; Garcia, Carmen; Gonzalez, Sergio; Kodys, Peter; Kubik, Petr; Lacasta, Carlos; Marti, Salvador; Mitsou, Vasiliki A.; Moorhead, Gareth F.; Phillips, Peter W.; Reznicek, Pavel; Slavik, Radan

    2007-01-01

    This paper collects experiences from the development of a silicon sensor laser testing setup and from tests of silicon strip modules (ATLAS End-cap SCT), pixel modules (DEPFET) and large-area diodes using semiconductor lasers. Lasers of 1060 and 680 nm wavelengths were used. A sophisticated method of focusing the laser was developed. Timing and interstrip properties of modules were measured. Analysis of optical effects involved and detailed discussion about the usability of laser testing for particle detectors are presented

  6. A Markov chain Monte Carlo Expectation Maximization Algorithm for Statistical Analysis of DNA Sequence Evolution with Neighbor-Dependent Substitution Rates

    DEFF Research Database (Denmark)

    Hobolth, Asger

    2008-01-01

    The evolution of DNA sequences can be described by discrete state continuous time Markov processes on a phylogenetic tree. We consider neighbor-dependent evolutionary models where the instantaneous rate of substitution at a site depends on the states of the neighboring sites. Neighbor...

  7. Aftershock identification problem via the nearest-neighbor analysis for marked point processes

    Science.gov (United States)

    Gabrielov, A.; Zaliapin, I.; Wong, H.; Keilis-Borok, V.

    2007-12-01

    The centennial observations on the world seismicity have revealed a wide variety of clustering phenomena that unfold in the space-time-energy domain and provide most reliable information about the earthquake dynamics. However, there is neither a unifying theory nor a convenient statistical apparatus that would naturally account for the different types of seismic clustering. In this talk we present a theoretical framework for nearest-neighbor analysis of marked processes and obtain new results on hierarchical approach to studying seismic clustering introduced by Baiesi and Paczuski (2004). Recall that under this approach one defines an asymmetric distance D in space-time-energy domain such that the nearest-neighbor spanning graph with respect to D becomes a time- oriented tree. We demonstrate how this approach can be used to detect earthquake clustering. We apply our analysis to the observed seismicity of California and synthetic catalogs from ETAS model and show that the earthquake clustering part is statistically different from the homogeneous part. This finding may serve as a basis for an objective aftershock identification procedure.

  8. A Distributed Approach to Continuous Monitoring of Constrained k-Nearest Neighbor Queries in Road Networks

    Directory of Open Access Journals (Sweden)

    Hyung-Ju Cho

    2012-01-01

    Full Text Available Given two positive parameters k and r, a constrained k-nearest neighbor (CkNN query returns the k closest objects within a network distance r of the query location in road networks. In terms of the scalability of monitoring these CkNN queries, existing solutions based on central processing at a server suffer from a sudden and sharp rise in server load as well as messaging cost as the number of queries increases. In this paper, we propose a distributed and scalable scheme called DAEMON for the continuous monitoring of CkNN queries in road networks. Our query processing is distributed among clients (query objects and server. Specifically, the server evaluates CkNN queries issued at intersections of road segments, retrieves the objects on the road segments between neighboring intersections, and sends responses to the query objects. Finally, each client makes its own query result using this server response. As a result, our distributed scheme achieves close-to-optimal communication costs and scales well to large numbers of monitoring queries. Exhaustive experimental results demonstrate that our scheme substantially outperforms its competitor in terms of query processing time and messaging cost.

  9. Gastronomy Tourism in Several Neighbor Countries of Indonesia: a Brief Review

    Directory of Open Access Journals (Sweden)

    Kurniasih Sukenti

    2014-04-01

    Full Text Available Gastronomy tourism, also called culinary tourism or food tourism, is a kind of tourism that provide attractions based on the culinary aspect owned by a country, region, or area. It is not only offers food and beverages as the main objects in its attractions, but also everything related to food activities ranging from food ingredients, preparation, processing, serving, as well as the cultural and local values. A well-managed culinary tourism will be a supportive program in developing and enhancing the tourism sector in a country. The objective of this paper is to describe the profile of gastronomy tourism in several neighbor countries of Indonesia, i.e. Hongkong, Singapore, Thailand, and Malaysia. This brief review is also discussed the potential of Indonesia gastronomy in supporting government’s tourism program. Basically, Indonesia has more enormous potential asset in managing its cultural heritages in term of culinary than its neighbor countries. A well-managed gastronomy tourism plays not only an important role in enhancing the economic sector, but also contribute in preserving the natural and cultural resources. Keywords: gastronomy tourism, culinary tourism, food tourism.

  10. Hyperplane distance neighbor clustering based on local discriminant analysis for complex chemical processes monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chunhong; Xiao, Shaoqing; Gu, Xiaofeng [Jiangnan University, Wuxi (China)

    2014-11-15

    The collected training data often include both normal and faulty samples for complex chemical processes. However, some monitoring methods, such as partial least squares (PLS), principal component analysis (PCA), independent component analysis (ICA) and Fisher discriminant analysis (FDA), require fault-free data to build the normal operation model. These techniques are applicable after the preliminary step of data clustering is applied. We here propose a novel hyperplane distance neighbor clustering (HDNC) based on the local discriminant analysis (LDA) for chemical process monitoring. First, faulty samples are separated from normal ones using the HDNC method. Then, the optimal subspace for fault detection and classification can be obtained using the LDA approach. The proposed method takes the multimodality within the faulty data into account, and thus improves the capability of process monitoring significantly. The HDNC-LDA monitoring approach is applied to two simulation processes and then compared with the conventional FDA based on the K-nearest neighbor (KNN-FDA) method. The results obtained in two different scenarios demonstrate the superiority of the HDNC-LDA approach in terms of fault detection and classification accuracy.

  11. Interacting Effects Induced by Two Neighboring Pits Considering Relative Position Parameters and Pit Depth

    Directory of Open Access Journals (Sweden)

    Yongfang Huang

    2017-04-01

    Full Text Available For pre-corroded aluminum alloy 7075-T6, the interacting effects of two neighboring pits on the stress concentration are comprehensively analyzed by considering various relative position parameters (inclination angle θ and dimensionless spacing parameter λ and pit depth (d with the finite element method. According to the severity of the stress concentration, the critical corrosion regions, bearing high susceptibility to fatigue damage, are determined for intersecting and adjacent pits, respectively. A straightforward approach is accordingly proposed to conservatively estimate the combined stress concentration factor induced by two neighboring pits, and a concrete application example is presented. It is found that for intersecting pits, the normalized stress concentration factor Ktnor increases with the increase of θ and λ and always reaches its maximum at θ = 90°, yet for adjacent pits, Ktnor decreases with the increase of λ and the maximum value appears at a slight asymmetric location. The simulations reveal that Ktnor follows a linear and an exponential relationship with the dimensionless depth parameter Rd for intersecting and adjacent cases, respectively.

  12. Sistem Rekomendasi Pada E-Commerce Menggunakan K-Nearest Neighbor

    Directory of Open Access Journals (Sweden)

    Chandra Saha Dewa Prasetya

    2017-09-01

    The growing number of product information available on the internet brings challenges to both customer and online businesses in the e-commerce environment. Customer often have difficulty when looking for products on the internet because of the number of products sold on the internet. In addition, online businessman often experience difficulties because they has much data about products, customers and transactions, thus causing online businessman have difficulty to promote the right product to a particular customer target. A recommendation system was developed to address those problem with various methods such as Collaborative Filtering, ContentBased, and Hybrid. Collaborative filtering method uses customer’s rating data, content based using product content such as title or description, and hybrid using both as the basis of the recommendation. In this research, the k-nearest neighbor algorithm is used to determine the top-n product recommendations for each buyer. The result of this research method Content Based outperforms other methods because the sparse data, that is the condition where the number of rating given by the customers is relatively little compared the number of products available in e-commerce. Keywords: recomendation system, k-nearest neighbor, collaborative filtering, content based.

  13. Spectral neighbor analysis method for automated generation of quantum-accurate interatomic potentials

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Aidan P. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Multiscale Science Dept.; Swiler, Laura P. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Optimization and Uncertainty Quantification Dept.; Trott, Christian R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Scalable Algorithms Dept.; Foiles, Stephen M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Computational Materials and Data Science Dept.; Tucker, Garritt J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Computational Materials and Data Science Dept.; Drexel Univ., Philadelphia, PA (United States). Dept. of Materials Science and Engineering

    2015-03-15

    Here, we present a new interatomic potential for solids and liquids called Spectral Neighbor Analysis Potential (SNAP). The SNAP potential has a very general form and uses machine-learning techniques to reproduce the energies, forces, and stress tensors of a large set of small configurations of atoms, which are obtained using high-accuracy quantum electronic structure (QM) calculations. The local environment of each atom is characterized by a set of bispectrum components of the local neighbor density projected onto a basis of hyperspherical harmonics in four dimensions. The bispectrum components are the same bond-orientational order parameters employed by the GAP potential [1]. The SNAP potential, unlike GAP, assumes a linear relationship between atom energy and bispectrum components. The linear SNAP coefficients are determined using weighted least-squares linear regression against the full QM training set. This allows the SNAP potential to be fit in a robust, automated manner to large QM data sets using many bispectrum components. The calculation of the bispectrum components and the SNAP potential are implemented in the LAMMPS parallel molecular dynamics code. We demonstrate that a previously unnoticed symmetry property can be exploited to reduce the computational cost of the force calculations by more than one order of magnitude. We present results for a SNAP potential for tantalum, showing that it accurately reproduces a range of commonly calculated properties of both the crystalline solid and the liquid phases. In addition, unlike simpler existing potentials, SNAP correctly predicts the energy barrier for screw dislocation migration in BCC tantalum.

  14. Spectral neighbor analysis method for automated generation of quantum-accurate interatomic potentials

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, A.P., E-mail: athomps@sandia.gov [Multiscale Science Department, Sandia National Laboratories, PO Box 5800, MS 1322, Albuquerque, NM 87185 (United States); Swiler, L.P., E-mail: lpswile@sandia.gov [Optimization and Uncertainty Quantification Department, Sandia National Laboratories, PO Box 5800, MS 1318, Albuquerque, NM 87185 (United States); Trott, C.R., E-mail: crtrott@sandia.gov [Scalable Algorithms Department, Sandia National Laboratories, PO Box 5800, MS 1322, Albuquerque, NM 87185 (United States); Foiles, S.M., E-mail: foiles@sandia.gov [Computational Materials and Data Science Department, Sandia National Laboratories, PO Box 5800, MS 1411, Albuquerque, NM 87185 (United States); Tucker, G.J., E-mail: gtucker@coe.drexel.edu [Computational Materials and Data Science Department, Sandia National Laboratories, PO Box 5800, MS 1411, Albuquerque, NM 87185 (United States); Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104 (United States)

    2015-03-15

    We present a new interatomic potential for solids and liquids called Spectral Neighbor Analysis Potential (SNAP). The SNAP potential has a very general form and uses machine-learning techniques to reproduce the energies, forces, and stress tensors of a large set of small configurations of atoms, which are obtained using high-accuracy quantum electronic structure (QM) calculations. The local environment of each atom is characterized by a set of bispectrum components of the local neighbor density projected onto a basis of hyperspherical harmonics in four dimensions. The bispectrum components are the same bond-orientational order parameters employed by the GAP potential [1]. The SNAP potential, unlike GAP, assumes a linear relationship between atom energy and bispectrum components. The linear SNAP coefficients are determined using weighted least-squares linear regression against the full QM training set. This allows the SNAP potential to be fit in a robust, automated manner to large QM data sets using many bispectrum components. The calculation of the bispectrum components and the SNAP potential are implemented in the LAMMPS parallel molecular dynamics code. We demonstrate that a previously unnoticed symmetry property can be exploited to reduce the computational cost of the force calculations by more than one order of magnitude. We present results for a SNAP potential for tantalum, showing that it accurately reproduces a range of commonly calculated properties of both the crystalline solid and the liquid phases. In addition, unlike simpler existing potentials, SNAP correctly predicts the energy barrier for screw dislocation migration in BCC tantalum.

  15. Predicting Audience Location on the Basis of the k-Nearest Neighbor Multilabel Classification

    Directory of Open Access Journals (Sweden)

    Haitao Wu

    2014-01-01

    Full Text Available Understanding audience location information in online social networks is important in designing recommendation systems, improving information dissemination, and so on. In this paper, we focus on predicting the location distribution of audiences on YouTube. And we transform this problem to a multilabel classification problem, while we find there exist three problems when the classical k-nearest neighbor based algorithm for multilabel classification (ML-kNN is used to predict location distribution. Firstly, the feature weights are not considered in measuring the similarity degree. Secondly, it consumes considerable computing time in finding similar items by traversing all the training set. Thirdly, the goal of ML-kNN is to find relevant labels for every sample which is different from audience location prediction. To solve these problems, we propose the methods of measuring similarity based on weight, quickly finding similar items, and ranking a specific number of labels. On the basis of these methods and the ML-kNN, the k-nearest neighbor based model for audience location prediction (AL-kNN is proposed for predicting audience location. The experiments based on massive YouTube data show that the proposed model can more accurately predict the location of YouTube video audience than the ML-kNN, MLNB, and Rank-SVM methods.

  16. Automated web usage data mining and recommendation system using K-Nearest Neighbor (KNN classification method

    Directory of Open Access Journals (Sweden)

    D.A. Adeniyi

    2016-01-01

    Full Text Available The major problem of many on-line web sites is the presentation of many choices to the client at a time; this usually results to strenuous and time consuming task in finding the right product or information on the site. In this work, we present a study of automatic web usage data mining and recommendation system based on current user behavior through his/her click stream data on the newly developed Really Simple Syndication (RSS reader website, in order to provide relevant information to the individual without explicitly asking for it. The K-Nearest-Neighbor (KNN classification method has been trained to be used on-line and in Real-Time to identify clients/visitors click stream data, matching it to a particular user group and recommend a tailored browsing option that meet the need of the specific user at a particular time. To achieve this, web users RSS address file was extracted, cleansed, formatted and grouped into meaningful session and data mart was developed. Our result shows that the K-Nearest Neighbor classifier is transparent, consistent, straightforward, simple to understand, high tendency to possess desirable qualities and easy to implement than most other machine learning techniques specifically when there is little or no prior knowledge about data distribution.

  17. Competing growth processes induced by next-nearest-neighbor interactions: Effects on meandering wavelength and stiffness

    Science.gov (United States)

    Blel, Sonia; Hamouda, Ajmi BH.; Mahjoub, B.; Einstein, T. L.

    2017-02-01

    In this paper we explore the meandering instability of vicinal steps with a kinetic Monte Carlo simulations (kMC) model including the attractive next-nearest-neighbor (NNN) interactions. kMC simulations show that increase of the NNN interaction strength leads to considerable reduction of the meandering wavelength and to weaker dependence of the wavelength on the deposition rate F. The dependences of the meandering wavelength on the temperature and the deposition rate obtained with simulations are in good quantitative agreement with the experimental result on the meandering instability of Cu(0 2 24) [T. Maroutian et al., Phys. Rev. B 64, 165401 (2001), 10.1103/PhysRevB.64.165401]. The effective step stiffness is found to depend not only on the strength of NNN interactions and the Ehrlich-Schwoebel barrier, but also on F. We argue that attractive NNN interactions intensify the incorporation of adatoms at step edges and enhance step roughening. Competition between NNN and nearest-neighbor interactions results in an alternative form of meandering instability which we call "roughening-limited" growth, rather than attachment-detachment-limited growth that governs the Bales-Zangwill instability. The computed effective wavelength and the effective stiffness behave as λeff˜F-q and β˜eff˜F-p , respectively, with q ≈p /2 .

  18. Neighbor Detection Induces Organ-Specific Transcriptomes, Revealing Patterns Underlying Hypocotyl-Specific Growth.

    Science.gov (United States)

    Kohnen, Markus V; Schmid-Siegert, Emanuel; Trevisan, Martine; Petrolati, Laure Allenbach; Sénéchal, Fabien; Müller-Moulé, Patricia; Maloof, Julin; Xenarios, Ioannis; Fankhauser, Christian

    2016-12-01

    In response to neighbor proximity, plants increase the growth of specific organs (e.g., hypocotyls) to enhance access to sunlight. Shade enhances the activity of Phytochrome Interacting Factors (PIFs) by releasing these bHLH transcription factors from phytochrome B-mediated inhibition. PIFs promote elongation by inducing auxin production in cotyledons. In order to elucidate spatiotemporal aspects of the neighbor proximity response, we separately analyzed gene expression patterns in the major light-sensing organ (cotyledons) and in rapidly elongating hypocotyls of Arabidopsis thaliana PIFs initiate transcriptional reprogramming in both organs within 15 min, comprising regulated expression of several early auxin response genes. This suggests that hypocotyl growth is elicited by both local and distal auxin signals. We show that cotyledon-derived auxin is both necessary and sufficient to initiate hypocotyl growth, but we also provide evidence for the functional importance of the local PIF-induced response. With time, the transcriptional response diverges increasingly between organs. We identify genes whose differential expression may underlie organ-specific elongation. Finally, we uncover a growth promotion gene expression signature shared between different developmentally regulated growth processes and responses to the environment in different organs. © 2016 American Society of Plant Biologists. All rights reserved.

  19. Spectral neighbor analysis method for automated generation of quantum-accurate interatomic potentials

    International Nuclear Information System (INIS)

    Thompson, A.P.; Swiler, L.P.; Trott, C.R.; Foiles, S.M.; Tucker, G.J.

    2015-01-01

    We present a new interatomic potential for solids and liquids called Spectral Neighbor Analysis Potential (SNAP). The SNAP potential has a very general form and uses machine-learning techniques to reproduce the energies, forces, and stress tensors of a large set of small configurations of atoms, which are obtained using high-accuracy quantum electronic structure (QM) calculations. The local environment of each atom is characterized by a set of bispectrum components of the local neighbor density projected onto a basis of hyperspherical harmonics in four dimensions. The bispectrum components are the same bond-orientational order parameters employed by the GAP potential [1]. The SNAP potential, unlike GAP, assumes a linear relationship between atom energy and bispectrum components. The linear SNAP coefficients are determined using weighted least-squares linear regression against the full QM training set. This allows the SNAP potential to be fit in a robust, automated manner to large QM data sets using many bispectrum components. The calculation of the bispectrum components and the SNAP potential are implemented in the LAMMPS parallel molecular dynamics code. We demonstrate that a previously unnoticed symmetry property can be exploited to reduce the computational cost of the force calculations by more than one order of magnitude. We present results for a SNAP potential for tantalum, showing that it accurately reproduces a range of commonly calculated properties of both the crystalline solid and the liquid phases. In addition, unlike simpler existing potentials, SNAP correctly predicts the energy barrier for screw dislocation migration in BCC tantalum

  20. Exposure measurement in the neighboring hospital beds during an x-ray procedure in hospitalization unit

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Rafael E.; Capeleti, Felipe F.; Cabete, Henrique V., E-mail: rafael.goto@fcmsantacasasp.edu.br, E-mail: felipe.capeleti@fcmsantacasasp.edu.br, E-mail: henrique@gmpbrasil.com.br [Faculdade de Ciencias Medicas da Santa Casa Sao Paulo, SP (Brazil); GMP Consultoria em Radioprotecao e Fisica Medica e Assessoria LTDA, Sao Paulo, SP (Brazil)

    2017-11-01

    There are lots of discussion about the exposure in hospitalization units in Brazil, especially around labor legislation and economic advantages of unhealthiness. With the attention focused on hospitalized patients, there were measured the exposure in neighboring beds of the patient submitted to an X-ray procedure with a mobile X-ray system that could be used to illustrate the discussion with consistent values. The most common X-ray procedure made in hospitalization units are chests images with techniques between 70 to 120 kV and 5 to 20 mAs. The measurement was made during routine exposure and simulations using a scattering phantom with Radcal AccuPro electrometer and 1800cc ionization chamber in a private hospital and a philanthropic hospital, both in Sao Paulo, Brazil. The ionization chambers are placed at 2 meters distance of the patient exposed of both sides during the routine procedure. During the simulation, a nylon phantom of 20 centimeters thick and 30 x 30 cm² size was placed on the bed, a typical exposure technique was used and the exposure was measured surrounding the phantom at 0.6, 1.0 and 2.0 meters distance for scattered radiation characterization. Initial results showed that the neighboring exposure at about 2 meters distance from the exposed patient bed have low values, even when exposure is integrated during the length of hospital stay. Therefore, the exposure in hospitalization units are very low compared to the exams doses. (author). (author)

  1. Carbon-hydrogen defects with a neighboring oxygen atom in n-type Si

    Science.gov (United States)

    Gwozdz, K.; Stübner, R.; Kolkovsky, Vl.; Weber, J.

    2017-07-01

    We report on the electrical activation of neutral carbon-oxygen complexes in Si by wet-chemical etching at room temperature. Two deep levels, E65 and E75, are observed by deep level transient spectroscopy in n-type Czochralski Si. The activation enthalpies of E65 and E75 are obtained as EC-0.11 eV (E65) and EC-0.13 eV (E75). The electric field dependence of their emission rates relates both levels to single acceptor states. From the analysis of the depth profiles, we conclude that the levels belong to two different defects, which contain only one hydrogen atom. A configuration is proposed, where the CH1BC defect, with hydrogen in the bond-centered position between neighboring C and Si atoms, is disturbed by interstitial oxygen in the second nearest neighbor position to substitutional carbon. The significant reduction of the CH1BC concentration in samples with high oxygen concentrations limits the use of this defect for the determination of low concentrations of substitutional carbon in Si samples.

  2. Disentangling neighbors and extended range density oscillations in monatomic amorphous semiconductors.

    Science.gov (United States)

    Roorda, S; Martin, C; Droui, M; Chicoine, M; Kazimirov, A; Kycia, S

    2012-06-22

    High energy x-ray diffraction measurements of pure amorphous Ge were made and its radial distribution function (RDF) was determined at high resolution, revealing new information on the atomic structure of amorphous semiconductors. Fine structure in the second peak in the RDF provides evidence that a fraction of third neighbors are closer than some second neighbors; taking this into account leads to a narrow distribution of tetrahedral bond angles, (8.5 ± 0.1)°. A small peak which appears near 5 Å upon thermal annealing shows that some ordering in the dihedral bond-angle distribution takes place during structural relaxation. Extended range order is detected (in both a-Ge and a-Si) which persists to beyond 20 Å, and both the periodicity and its decay length increase upon thermal annealing. Previously, the effect of structural relaxation was only detected at intermediate range, involving reduced tetrahedral bond-angle distortions. These results enhance our understanding of the atomic order in continuous random networks and place significantly more stringent requirements on computer models intending to describe these networks, or their alternatives which attempt to describe the structure in terms of an arrangement of paracrystals.

  3. Mapping DNA methylation by transverse current sequencing: Reduction of noise from neighboring nucleotides

    Science.gov (United States)

    Alvarez, Jose; Massey, Steven; Kalitsov, Alan; Velev, Julian

    Nanopore sequencing via transverse current has emerged as a competitive candidate for mapping DNA methylation without needed bisulfite-treatment, fluorescent tag, or PCR amplification. By eliminating the error producing amplification step, long read lengths become feasible, which greatly simplifies the assembly process and reduces the time and the cost inherent in current technologies. However, due to the large error rates of nanopore sequencing, single base resolution has not been reached. A very important source of noise is the intrinsic structural noise in the electric signature of the nucleotide arising from the influence of neighboring nucleotides. In this work we perform calculations of the tunneling current through DNA molecules in nanopores using the non-equilibrium electron transport method within an effective multi-orbital tight-binding model derived from first-principles calculations. We develop a base-calling algorithm accounting for the correlations of the current through neighboring bases, which in principle can reduce the error rate below any desired precision. Using this method we show that we can clearly distinguish DNA methylation and other base modifications based on the reading of the tunneling current.

  4. Data delivery method based on neighbor nodes' information in a mobile ad hoc network.

    Science.gov (United States)

    Kashihara, Shigeru; Hayashi, Takuma; Taenaka, Yuzo; Okuda, Takeshi; Yamaguchi, Suguru

    2014-01-01

    This paper proposes a data delivery method based on neighbor nodes' information to achieve reliable communication in a mobile ad hoc network (MANET). In a MANET, it is difficult to deliver data reliably due to instabilities in network topology and wireless network condition which result from node movement. To overcome such unstable communication, opportunistic routing and network coding schemes have lately attracted considerable attention. Although an existing method that employs such schemes, MAC-independent opportunistic routing and encoding (MORE), Chachulski et al. (2007), improves the efficiency of data delivery in an unstable wireless mesh network, it does not address node movement. To efficiently deliver data in a MANET, the method proposed in this paper thus first employs the same opportunistic routing and network coding used in MORE and also uses the location information and transmission probabilities of neighbor nodes to adapt to changeable network topology and wireless network condition. The simulation experiments showed that the proposed method can achieve efficient data delivery with low network load when the movement speed is relatively slow.

  5. Data Delivery Method Based on Neighbor Nodes’ Information in a Mobile Ad Hoc Network

    Directory of Open Access Journals (Sweden)

    Shigeru Kashihara

    2014-01-01

    Full Text Available This paper proposes a data delivery method based on neighbor nodes’ information to achieve reliable communication in a mobile ad hoc network (MANET. In a MANET, it is difficult to deliver data reliably due to instabilities in network topology and wireless network condition which result from node movement. To overcome such unstable communication, opportunistic routing and network coding schemes have lately attracted considerable attention. Although an existing method that employs such schemes, MAC-independent opportunistic routing and encoding (MORE, Chachulski et al. (2007, improves the efficiency of data delivery in an unstable wireless mesh network, it does not address node movement. To efficiently deliver data in a MANET, the method proposed in this paper thus first employs the same opportunistic routing and network coding used in MORE and also uses the location information and transmission probabilities of neighbor nodes to adapt to changeable network topology and wireless network condition. The simulation experiments showed that the proposed method can achieve efficient data delivery with low network load when the movement speed is relatively slow.

  6. Power-Controlled MAC Protocols with Dynamic Neighbor Prediction for Ad hoc Networks

    Institute of Scientific and Technical Information of China (English)

    LI Meng; ZHANG Lin; XIAO Yong-kang; SHAN Xiu-ming

    2004-01-01

    Energy and bandwidth are the scarce resources in ad hoc networks because most of the mobile nodes are battery-supplied and share the exclusive wireless medium. Integrating the power control into MAC protocol is a promising technique to fully exploit these precious resources of ad hoc wireless networks. In this paper, a new intelligent power-controlled Medium Access Control (MAC) (iMAC) protocol with dynamic neighbor prediction is proposed. Through the elaborate design of the distributed transmit-receive strategy of mobile nodes, iMAC greatly outperforms the prevailing IEEE 802.11 MAC protocols in not only energy conservation but also network throughput. Using the Dynamic Neighbor Prediction (DNP), iMAC performs well in mobile scenes. To the best of our knowledge, iMAC is the first protocol that considers the performance deterioration of power-controlled MAC protocols in mobile scenes and then proposes a solution. Simulation results indicate that DNP is important and necessary for power-controlled MAC protocols in mobile ad hoc networks.

  7. Sequential nearest-neighbor effects on computed {sup 13}C{sup {alpha}} chemical shifts

    Energy Technology Data Exchange (ETDEWEB)

    Vila, Jorge A. [Cornell University, Baker Laboratory of Chemistry and Chemical Biology (United States); Serrano, Pedro; Wuethrich, Kurt [The Scripps Research Institute, Department of Molecular Biology (United States); Scheraga, Harold A., E-mail: has5@cornell.ed [Cornell University, Baker Laboratory of Chemistry and Chemical Biology (United States)

    2010-09-15

    To evaluate sequential nearest-neighbor effects on quantum-chemical calculations of {sup 13}C{sup {alpha}} chemical shifts, we selected the structure of the nucleic acid binding (NAB) protein from the SARS coronavirus determined by NMR in solution (PDB id 2K87). NAB is a 116-residue {alpha}/{beta} protein, which contains 9 prolines and has 50% of its residues located in loops and turns. Overall, the results presented here show that sizeable nearest-neighbor effects are seen only for residues preceding proline, where Pro introduces an overestimation, on average, of 1.73 ppm in the computed {sup 13}C{sup {alpha}} chemical shifts. A new ensemble of 20 conformers representing the NMR structure of the NAB, which was calculated with an input containing backbone torsion angle constraints derived from the theoretical {sup 13}C{sup {alpha}} chemical shifts as supplementary data to the NOE distance constraints, exhibits very similar topology and comparable agreement with the NOE constraints as the published NMR structure. However, the two structures differ in the patterns of differences between observed and computed {sup 13}C{sup {alpha}} chemical shifts, {Delta}{sub ca,i}, for the individual residues along the sequence. This indicates that the {Delta}{sub ca,i} -values for the NAB protein are primarily a consequence of the limited sampling by the bundles of 20 conformers used, as in common practice, to represent the two NMR structures, rather than of local flaws in the structures.

  8. δ-Generalized Labeled Multi-Bernoulli Filter Using Amplitude Information of Neighboring Cells

    Directory of Open Access Journals (Sweden)

    Chao Liu

    2018-04-01

    Full Text Available The amplitude information (AI of echoed signals plays an important role in radar target detection and tracking. A lot of research shows that the introduction of AI enables the tracking algorithm to distinguish targets from clutter better and then improves the performance of data association. The current AI-aided tracking algorithms only consider the signal amplitude in the range-azimuth cell where measurement exists. However, since radar echoes always contain backscattered signals from multiple cells, the useful information of neighboring cells would be lost if directly applying those existing methods. In order to solve this issue, a new δ-generalized labeled multi-Bernoulli (δ-GLMB filter is proposed. It exploits the AI of radar echoes from neighboring cells to construct a united amplitude likelihood ratio, and then plugs it into the update process and the measurement-track assignment cost matrix of the δ-GLMB filter. Simulation results show that the proposed approach has better performance in target’s state and number estimation than that of the δ-GLMB only using single-cell AI in low signal-to-clutter-ratio (SCR environment.

  9. Hyperplane distance neighbor clustering based on local discriminant analysis for complex chemical processes monitoring

    International Nuclear Information System (INIS)

    Lu, Chunhong; Xiao, Shaoqing; Gu, Xiaofeng

    2014-01-01

    The collected training data often include both normal and faulty samples for complex chemical processes. However, some monitoring methods, such as partial least squares (PLS), principal component analysis (PCA), independent component analysis (ICA) and Fisher discriminant analysis (FDA), require fault-free data to build the normal operation model. These techniques are applicable after the preliminary step of data clustering is applied. We here propose a novel hyperplane distance neighbor clustering (HDNC) based on the local discriminant analysis (LDA) for chemical process monitoring. First, faulty samples are separated from normal ones using the HDNC method. Then, the optimal subspace for fault detection and classification can be obtained using the LDA approach. The proposed method takes the multimodality within the faulty data into account, and thus improves the capability of process monitoring significantly. The HDNC-LDA monitoring approach is applied to two simulation processes and then compared with the conventional FDA based on the K-nearest neighbor (KNN-FDA) method. The results obtained in two different scenarios demonstrate the superiority of the HDNC-LDA approach in terms of fault detection and classification accuracy

  10. Direct Production of Silicones From Sand

    Energy Technology Data Exchange (ETDEWEB)

    Larry N. Lewis; F.J. Schattenmann: J.P. Lemmon

    2001-09-30

    Silicon, in the form of silica and silicates, is the second most abundant element in the earth's crust. However the synthesis of silicones (scheme 1) and almost all organosilicon chemistry is only accessible through elemental silicon. Silicon dioxide (sand or quartz) is converted to chemical-grade elemental silicon in an energy intensive reduction process, a result of the exceptional thermodynamic stability of silica. Then, the silicon is reacted with methyl chloride to give a mixture of methylchlorosilanes catalyzed by cooper containing a variety of tract metals such as tin, zinc etc. The so-called direct process was first discovered at GE in 1940. The methylchlorosilanes are distilled to purify and separate the major reaction components, the most important of which is dimethyldichlorosilane. Polymerization of dimethyldichlorosilane by controlled hydrolysis results in the formation of silicone polymers. Worldwide, the silicones industry produces about 1.3 billion pounds of the basic silicon polymer, polydimethylsiloxane.

  11. Enhanced Raman scattering in porous silicon grating.

    Science.gov (United States)

    Wang, Jiajia; Jia, Zhenhong; Lv, Changwu

    2018-03-19

    The enhancement of Raman signal on monocrystalline silicon gratings with varying groove depths and on porous silicon grating were studied for a highly sensitive surface enhanced Raman scattering (SERS) response. In the experiment conducted, porous silicon gratings were fabricated. Silver nanoparticles (Ag NPs) were then deposited on the porous silicon grating to enhance the Raman signal of the detective objects. Results show that the enhancement of Raman signal on silicon grating improved when groove depth increased. The enhanced performance of Raman signal on porous silicon grating was also further improved. The Rhodamine SERS response based on Ag NPs/ porous silicon grating substrates was enhanced relative to the SERS response on Ag NPs/ porous silicon substrates. Ag NPs / porous silicon grating SERS substrate system achieved a highly sensitive SERS response due to the coupling of various Raman enhancement factors.

  12. Silicon Photomultiplier charaterization

    Science.gov (United States)

    Munoz, Leonel; Osornio, Leo; Para, Adam

    2014-03-01

    Silicon Photo Multiples (SiPM's) are relatively new photon detectors. They offer many advantages compared to photo multiplier tubes (PMT's) such as insensitivity to magnetic field, robustness at varying lighting levels, and low cost. The SiPM output wave forms are poorly understood. The experiment conducted collected waveforms of responses of Hamamatsu SiPM to incident laser pulse at varying temperatures and bias voltages. Ambient noise was characterized at all temperatures and bias voltages by averaging the waveforms. Pulse shape of the SiPM response was determined under different operating conditions: the pulse shape is nearly independent of the bias voltage but exhibits strong variation with temperature, consistent with the temperature variation of the quenching resistor. Amplitude of responses of the SiPM to low intensity laser light shows many peaks corresponding to the detection of 1,2,3 etc. photons. Amplitude of these pulses depends linearly on the bias voltage, enabling determination of the breakdown voltage at each temperature. Poisson statistics has been used to determine the average number of detected photons at each operating conditions. Department of Education Grant No. P0315090007 and the Department of Energy/ Fermi National Accelerator Laboratory.

  13. Collimation: a silicon solution

    CERN Multimedia

    2007-01-01

    Silicon crystals could be used very efficiently to deflect high-energy beams. Testing at CERN has produced conclusive results, which could pave the way for a new generation of collimators. The set of five crystals used to test the reflection of the beams. The crystals are 0.75 mm wide and their alignment is adjusted with extreme precision. This figure shows the deflection of a beam by channelling and by reflection in the block of five crystals. Depending on the orientation of the crystals: 1) The beam passes without "seeing" the crystals and is not deflected 2) The beam is deflected by channelling (with an angle of around 100 μrad) 3) The beam is reflected (with an angle of around 50 μrad). The intensity of the deflected beam is illustrated by the intensity of the spot. The spot of the reflected beam is clearly more intense than that one of the channelled beam, demonstrating the efficiency of t...

  14. Historical harvests reduce neighboring old-growth basal area across a forest landscape.

    Science.gov (United States)

    Bell, David M; Spies, Thomas A; Pabst, Robert

    2017-07-01

    While advances in remote sensing have made stand, landscape, and regional assessments of the direct impacts of disturbance on forests quite common, the edge influence of timber harvesting on the structure of neighboring unharvested forests has not been examined extensively. In this study, we examine the impact of historical timber harvests on basal area patterns of neighboring old-growth forests to assess the magnitude and scale of harvest edge influence in a forest landscape of western Oregon, USA. We used lidar data and forest plot measurements to construct 30-m resolution live tree basal area maps in lower and middle elevation mature and old-growth forests. We assessed how edge influence on total, upper canopy, and lower canopy basal area varied across this forest landscape as a function of harvest characteristics (i.e., harvest size and age) and topographic conditions in the unharvested area. Upper canopy, lower canopy, and total basal area increased with distance from harvest edge and elevation. Forests within 75 m of harvest edges (20% of unharvested forests) had 4% to 6% less live tree basal area compared with forest interiors. An interaction between distance from harvest edge and elevation indicated that elevation altered edge influence in this landscape. We observed a positive edge influence at low elevations (800 m). Surprisingly, we found no or weak effects of harvest age (13-60 yr) and harvest area (0.2-110 ha) on surrounding unharvested forest basal area, implying that edge influence was relatively insensitive to the scale of disturbance and multi-decadal recovery processes. Our study indicates that the edge influence of past clearcutting on the structure of neighboring uncut old-growth forests is widespread and persistent. These indirect and diffuse legacies of historical timber harvests complicate forest management decision-making in old-growth forest landscapes by broadening the traditional view of stand boundaries. Furthermore, the consequences

  15. Allotment gardening and health: a comparative survey among allotment gardeners and their neighbors without an allotment.

    Science.gov (United States)

    van den Berg, Agnes E; van Winsum-Westra, Marijke; de Vries, Sjerp; van Dillen, Sonja M E

    2010-11-23

    The potential contribution of allotment gardens to a healthy and active life-style is increasingly recognized, especially for elderly populations. However, few studies have empirically examined beneficial effects of allotment gardening. In the present study the health, well-being and physical activity of older and younger allotment gardeners was compared to that of controls without an allotment. A survey was conducted among 121 members of 12 allotment sites in the Netherlands and a control group of 63 respondents without an allotment garden living next to the home addresses of allotment gardeners. The survey included five self-reported health measures (perceived general health, acute health complaints, physical constraints, chronic illnesses, and consultations with GP), four self-reported well-being measures (stress, life satisfaction, loneliness, and social contacts with friends) and one measure assessing self-reported levels of physical activity in summer. Respondents were divided into a younger and older group at the median of 62 years which equals the average retirement age in the Netherlands. After adjusting for income, education level, gender, stressful life events, physical activity in winter, and access to a garden at home as covariates, both younger and older allotment gardeners reported higher levels of physical activity during the summer than neighbors in corresponding age categories. The impacts of allotment gardening on health and well-being were moderated by age. Allotment gardeners of 62 years and older scored significantly or marginally better on all measures of health and well-being than neighbors in the same age category. Health and well-being of younger allotment gardeners did not differ from younger neighbors. The greater health and well-being benefits of allotment gardening for older gardeners may be related to the finding that older allotment gardeners were more oriented towards gardening and being active, and less towards passive relaxation

  16. Allotment gardening and health: a comparative survey among allotment gardeners and their neighbors without an allotment

    Directory of Open Access Journals (Sweden)

    van Winsum-Westra Marijke

    2010-11-01

    Full Text Available Abstract Background The potential contribution of allotment gardens to a healthy and active life-style is increasingly recognized, especially for elderly populations. However, few studies have empirically examined beneficial effects of allotment gardening. In the present study the health, well-being and physical activity of older and younger allotment gardeners was compared to that of controls without an allotment. Methods A survey was conducted among 121 members of 12 allotment sites in the Netherlands and a control group of 63 respondents without an allotment garden living next to the home addresses of allotment gardeners. The survey included five self-reported health measures (perceived general health, acute health complaints, physical constraints, chronic illnesses, and consultations with GP, four self-reported well-being measures (stress, life satisfaction, loneliness, and social contacts with friends and one measure assessing self-reported levels of physical activity in summer. Respondents were divided into a younger and older group at the median of 62 years which equals the average retirement age in the Netherlands. Results After adjusting for income, education level, gender, stressful life events, physical activity in winter, and access to a garden at home as covariates, both younger and older allotment gardeners reported higher levels of physical activity during the summer than neighbors in corresponding age categories. The impacts of allotment gardening on health and well-being were moderated by age. Allotment gardeners of 62 years and older scored significantly or marginally better on all measures of health and well-being than neighbors in the same age category. Health and well-being of younger allotment gardeners did not differ from younger neighbors. The greater health and well-being benefits of allotment gardening for older gardeners may be related to the finding that older allotment gardeners were more oriented towards gardening

  17. Next generation structural silicone glazing

    Directory of Open Access Journals (Sweden)

    Charles D. Clift

    2015-06-01

    Full Text Available This paper presents an advanced engineering evaluation, using nonlinear analysis of hyper elastic material that provides significant improvement to structural silicone glazing (SSG design in high performance curtain wall systems. Very high cladding wind pressures required in hurricane zones often result in bulky SSG profile dimensions. Architectural desire for aesthetically slender curtain wall framing sight-lines in combination with a desire to reduce aluminium usage led to optimization of silicone material geometry for better stress distribution.To accomplish accurate simulation of predicted behaviour under structural load, robust stress-strain curves of the silicone material are essential. The silicone manufacturer provided physical property testing via a specialized laboratory protocol. A series of rigorous curve fit techniques were then made to closely model test data in the finite element computer analysis that accounts for nonlinear strain of hyper elastic silicone.Comparison of this advanced design technique to traditional SSG design highlights differences in stress distribution contours in the silicone material. Simplified structural engineering per the traditional SSG design method does not provide accurate forecasting of material and stress optimization as shown in the advanced design.Full-scale specimens subject to structural load testing were performed to verify the design capacity, not only for high wind pressure values, but also for debris impact per ASTM E1886 and ASTM E1996. Also, construction of the test specimens allowed development of SSG installation techniques necessitated by the unique geometry of the silicone profile. Finally, correlation of physical test results with theoretical simulations is made, so evaluation of design confidence is possible. This design technique will introduce significant engineering advancement to the curtain wall industry.

  18. Obstacle Detection for Intelligent Transportation Systems Using Deep Stacked Autoencoder and k-Nearest Neighbor Scheme

    KAUST Repository

    Dairi, Abdelkader; Harrou, Fouzi; Sun, Ying; Senouci, Mohamed

    2018-01-01

    Obstacle detection is an essential element for the development of intelligent transportation systems so that accidents can be avoided. In this study, we propose a stereovisionbased method for detecting obstacles in urban environment. The proposed method uses a deep stacked auto-encoders (DSA) model that combines the greedy learning features with the dimensionality reduction capacity and employs an unsupervised k-nearest neighbors algorithm (KNN) to accurately and reliably detect the presence of obstacles. We consider obstacle detection as an anomaly detection problem. We evaluated the proposed method by using practical data from three publicly available datasets, the Malaga stereovision urban dataset (MSVUD), the Daimler urban segmentation dataset (DUSD), and Bahnhof dataset. Also, we compared the efficiency of DSA-KNN approach to the deep belief network (DBN)-based clustering schemes. Results show that the DSA-KNN is suitable to visually monitor urban scenes.

  19. Phosphorous vacancy nearest neighbor hopping induced instabilities in InP capacitors II. Computer simulation

    International Nuclear Information System (INIS)

    Juang, M.T.; Wager, J.F.; Van Vechten, J.A.

    1988-01-01

    Drain current drift in InP metal insulator semiconductor devices display distinct activation energies and pre-exponential factors. The authors have given evidence that these result from two physical mechanisms: thermionic tunneling of electrons into native oxide traps and phosphorous vacancy nearest neighbor hopping (PVNNH). They here present a computer simulation of the effect of the PVNHH mechanism on flatband voltage shift vs. bias stress time measurements. The simulation is based on an analysis of the kinetics of the PVNNH defect reaction sequence in which the electron concentration in the channel is related to the applied bias by a solution of the Poisson equation. The simulation demonstrates quantitatively that the temperature dependence of the flatband shift is associated with PVNNH for temperatures above room temperature

  20. Thermodynamics of alternating spin chains with competing nearest- and next-nearest-neighbor interactions: Ising model

    Science.gov (United States)

    Pini, Maria Gloria; Rettori, Angelo

    1993-08-01

    The thermodynamical properties of an alternating spin (S,s) one-dimensional (1D) Ising model with competing nearest- and next-nearest-neighbor interactions are exactly calculated using a transfer-matrix technique. In contrast to the case S=s=1/2, previously investigated by Harada, the alternation of different spins (S≠s) along the chain is found to give rise to two-peaked static structure factors, signaling the coexistence of different short-range-order configurations. The relevance of our calculations with regard to recent experimental data by Gatteschi et al. in quasi-1D molecular magnetic materials, R (hfac)3 NITEt (R=Gd, Tb, Dy, Ho, Er, . . .), is discussed; hfac is hexafluoro-acetylacetonate and NlTEt is 2-Ethyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide.

  1. Proteomic characterization of host response to Yersinia pestis and near neighbors

    International Nuclear Information System (INIS)

    Chromy, Brett A.; Perkins, Julie; Heidbrink, Jenny L.; Gonzales, Arlene D.; Murphy, Gloria A.; Fitch, J. Patrick; McCutchen-Maloney, Sandra L.

    2004-01-01

    Host-pathogen interactions result in protein expression changes within both the host and the pathogen. Here, results from proteomic characterization of host response following exposure to Yersinia pestis, the causative agent of plague, and to two near neighbors, Yersinia pseudotuberculosis and Yersinia enterocolitica, are reported. Human monocyte-like cells were chosen as a model for macrophage immune response to pathogen exposure. Two-dimensional electrophoresis followed by mass spectrometry was used to identify host proteins with differential expression following exposure to these three closely related Yersinia species. This comparative proteomic characterization of host response clearly shows that host protein expression patterns are distinct for the different pathogen exposures, and contributes to further understanding of Y. pestis virulence and host defense mechanisms. This work also lays the foundation for future studies aimed at defining biomarkers for presymptomatic detection of plague

  2. False-nearest-neighbors algorithm and noise-corrupted time series

    International Nuclear Information System (INIS)

    Rhodes, C.; Morari, M.

    1997-01-01

    The false-nearest-neighbors (FNN) algorithm was originally developed to determine the embedding dimension for autonomous time series. For noise-free computer-generated time series, the algorithm does a good job in predicting the embedding dimension. However, the problem of predicting the embedding dimension when the time-series data are corrupted by noise was not fully examined in the original studies of the FNN algorithm. Here it is shown that with large data sets, even small amounts of noise can lead to incorrect prediction of the embedding dimension. Surprisingly, as the length of the time series analyzed by FNN grows larger, the cause of incorrect prediction becomes more pronounced. An analysis of the effect of noise on the FNN algorithm and a solution for dealing with the effects of noise are given here. Some results on the theoretically correct choice of the FNN threshold are also presented. copyright 1997 The American Physical Society

  3. Algoritma Interpolasi Nearest-Neighbor untuk Pendeteksian Sampul Pulsa Oscilometri Menggunakan Mikrokontroler Berbiaya Rendah

    Directory of Open Access Journals (Sweden)

    Firdaus Firdaus

    2017-12-01

    Full Text Available Non-invasive blood pressure measurement devices are widely available in the marketplace. Most of these devices use the oscillometric principle that store and analyze oscillometric waveforms during cuff deflation to obtain mean arterial pressure, systolic blood pressure and diastolic blood pressure. Those pressure values are determined from the oscillometric waveform envelope. Several methods to detect the envelope of oscillometric pulses utilize a complex algorithm that requires a large capacity memory and certainly difficult to process by a low memory capacity embedded system. A simple nearest-neighbor interpolation method is applied for oscillometric pulse envelope detection in non-invasive blood pressure measurement using microcontroller such ATmega328. The experiment yields 59 seconds average time to process the computation with 3.6% average percent error in blood pressure measurement.

  4. Tensile twin nucleation events coupled to neighboring slip observed in three dimensions

    International Nuclear Information System (INIS)

    Lind, J.; Li, S.F.; Pokharel, R.; Lienert, U.; Rollett, A.D.; Suter, R.M.

    2014-01-01

    Low-symmetry crystals and polycrystals have anisotropic mechanical properties which, given better understanding of their deformation modes, could lead to development of next generation materials. Understanding how grains in a bulk polycrystal interact will guide and improve material modeling. Here, we show that tensile twins, in hexagonal close-packed metals, form where the macroscopic stress does not generate appropriate shear stress and vice versa. We use non-destructive high-energy X-ray diffraction microscopy to map local crystal orientations in three dimensions in a series of tensile strain states in a zirconium polycrystal. Twins and intragranular orientation variations are observed and it is found that deformation-induced rotations in neighboring grains are spatially correlated with many twins. We conclude that deformation twinning involves complex multigrain interactions which must be included in polycrystal plasticity models

  5. Nearest neighbor spacing distributions of low-lying levels of vibrational nuclei

    International Nuclear Information System (INIS)

    Abul-Magd, A.Y.; Simbel, M.H.

    1996-01-01

    Energy-level statistics are considered for nuclei whose Hamiltonian is divided into intrinsic and collective-vibrational terms. The levels are described as a random superposition of independent sequences, each corresponding to a given number of phonons. The intrinsic motion is assumed chaotic. The level spacing distribution is found to be intermediate between the Wigner and Poisson distributions and similar in form to the spacing distribution of a system with classical phase space divided into separate regular and chaotic domains. We have obtained approximate expressions for the nearest neighbor spacing and cumulative spacing distribution valid when the level density is described by a constant-temperature formula and not involving additional free parameters. These expressions have been able to achieve good agreement with the experimental spacing distributions. copyright 1996 The American Physical Society

  6. Fringe field interference of neighbor magnets in China spallation neutron source

    International Nuclear Information System (INIS)

    Li, L.; Kang, W.; Wu, X.; Deng, C.D.; Li, S.; Yang, M.; Zhou, J.X.; Liu, Y.Q.; Wu, Y.W.

    2016-01-01

    In CSNS accelerator construction, the field measurement of all RCS magnets have been finished and the magnets have been installed in the tunnel before the end of 2015. The electromagnetic quadrupoles have a large aperture and the core-to-core distance between magnets is rather short in some places. The corrector magnet or the sextupole magnet is closer to one of the quadrupole magnets which caused certain interference. The interference caused by magnetic fringe field has been appeared and it becomes a significant issue in beam dynamics for beam loss control in this high-intensity proton accelerator. We have performed 3D computing simulations to study integral field distributions between the quadrupole and the corrector magnets, and the sextupole and the other quadrupole magnets. The effect of the magnetic fringe field and the interference has been investigated with different distances of the neighbor magnets. The simulation and the field measurement results will be introduced in this paper.

  7. A SURVEY ON DELAY AND NEIGHBOR NODE MONITORING BASED WORMHOLE ATTACK PREVENTION AND DETECTION

    Directory of Open Access Journals (Sweden)

    Sudhir T Bagade

    2016-12-01

    Full Text Available In Mobile Ad-hoc Networks (MANET, network layer attacks, for example wormhole attacks, disrupt the network routing operations and can be used for data theft. Wormhole attacks are of two types: hidden and exposed wormhole. There are various mechanisms in literature which are used to prevent and detect wormhole attacks. In this paper, we survey wormhole prevention and detection techniques and present our critical observations for each. These techniques are based on cryptographic mechanisms, monitoring of packet transmission delay and control packet forwarding behavior of neighbor nodes. We compare the techniques using the following criteria- extra resources needed applicability to different network topologies and routing protocols, prevention/detection capability, etc. We conclude the paper with potential research directions.

  8. K-Nearest Neighbor Intervals Based AP Clustering Algorithm for Large Incomplete Data

    Directory of Open Access Journals (Sweden)

    Cheng Lu

    2015-01-01

    Full Text Available The Affinity Propagation (AP algorithm is an effective algorithm for clustering analysis, but it can not be directly applicable to the case of incomplete data. In view of the prevalence of missing data and the uncertainty of missing attributes, we put forward a modified AP clustering algorithm based on K-nearest neighbor intervals (KNNI for incomplete data. Based on an Improved Partial Data Strategy, the proposed algorithm estimates the KNNI representation of missing attributes by using the attribute distribution information of the available data. The similarity function can be changed by dealing with the interval data. Then the improved AP algorithm can be applicable to the case of incomplete data. Experiments on several UCI datasets show that the proposed algorithm achieves impressive clustering results.

  9. Obstacle Detection for Intelligent Transportation Systems Using Deep Stacked Autoencoder and k-Nearest Neighbor Scheme

    KAUST Repository

    Dairi, Abdelkader

    2018-04-30

    Obstacle detection is an essential element for the development of intelligent transportation systems so that accidents can be avoided. In this study, we propose a stereovisionbased method for detecting obstacles in urban environment. The proposed method uses a deep stacked auto-encoders (DSA) model that combines the greedy learning features with the dimensionality reduction capacity and employs an unsupervised k-nearest neighbors algorithm (KNN) to accurately and reliably detect the presence of obstacles. We consider obstacle detection as an anomaly detection problem. We evaluated the proposed method by using practical data from three publicly available datasets, the Malaga stereovision urban dataset (MSVUD), the Daimler urban segmentation dataset (DUSD), and Bahnhof dataset. Also, we compared the efficiency of DSA-KNN approach to the deep belief network (DBN)-based clustering schemes. Results show that the DSA-KNN is suitable to visually monitor urban scenes.

  10. Probability-neighbor method of accelerating geometry treatment in reactor Monte Carlo code RMC

    International Nuclear Information System (INIS)

    She, Ding; Li, Zeguang; Xu, Qi; Wang, Kan; Yu, Ganglin

    2011-01-01

    Probability neighbor method (PNM) is proposed in this paper to accelerate geometry treatment of Monte Carlo (MC) simulation and validated in self-developed reactor Monte Carlo code RMC. During MC simulation by either ray-tracking or delta-tracking method, large amounts of time are spent in finding out which cell one particle is located in. The traditional way is to search cells one by one with certain sequence defined previously. However, this procedure becomes very time-consuming when the system contains a large number of cells. Considering that particles have different probability to enter different cells, PNM method optimizes the searching sequence, i.e., the cells with larger probability are searched preferentially. The PNM method is implemented in RMC code and the numerical results show that the considerable time of geometry treatment in MC calculation for complicated systems is saved, especially effective in delta-tracking simulation. (author)

  11. The patient-centered medical home neighbor: A primary care physician's view.

    Science.gov (United States)

    Sinsky, Christine A

    2011-01-04

    The American College of Physicians' position paper on the patient-centered medical home neighbor (PCMH-N) extends the work of the patient-centered medical home (PCMH) as a means of improving the delivery of health care. Recognizing that the PCMH does not exist in isolation, the PCMH-N concept outlines expectations for comanagement, communication, and care coordination and broadens responsibility for safe, effective, and efficient care beyond primary care to include physicians of all specialties. As such, it is a fitting follow-up to the PCMH and moves further down the road toward improved care for complex patients. Yet, there is more work to be done. Truly transforming the U.S. health care system around personalized medical homes embedded in highly functional medical neighborhoods will require better staffing models; more robust electronic information tools; aligned incentives for quality and efficiency within payment and regulatory policies; and a culture of greater engagement of patients, their families, and communities.

  12. Colloidal characterization of silicon nitride and silicon carbide

    Science.gov (United States)

    Feke, Donald L.

    1986-01-01

    The colloidal behavior of aqueous ceramic slips strongly affects the forming and sintering behavior and the ultimate mechanical strength of the final ceramic product. The colloidal behavior of these materials, which is dominated by electrical interactions between the particles, is complex due to the strong interaction of the solids with the processing fluids. A surface titration methodology, modified to account for this interaction, was developed and used to provide fundamental insights into the interfacial chemistry of these systems. Various powder pretreatment strategies were explored to differentiate between true surface chemistry and artifacts due to exposure history. The colloidal behavior of both silicon nitride and carbide is dominated by silanol groups on the powder surfaces. However, the colloid chemistry of silicon nitride is apparently influenced by an additional amine group. With the proper powder treatments, silicon nitride and carbide powder can be made to appear colloidally equivalent. The impact of these results on processing control will be discussed.

  13. Silicon-to-silicon wafer bonding using evaporated glass

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Lindahl, M.

    1998-01-01

    Anodic bending of silicon to silicon 4-in. wafers using an electron-beam evaporated glass (Schott 8329) was performed successfully in air at temperatures ranging from 200 degrees C to 450 degrees C. The composition of the deposited glass is enriched in sodium as compared to the target material....... The roughness of the as-deposited films was below 5 nm and was found to be unchanged by annealing at 500 degrees C for 1 h in air. No change in the macroscopic edge profiles of the glass film was found as a function of annealing; however, small extrusions appear when annealing above 450 degrees C. Annealing...... of silicon/glass structures in air around 340 degrees C for 15 min leads to stress-free structures. Bonded wafer pairs, however, show no reduction in stress and always exhibit compressive stress. The bond yield is larger than 95% for bonding temperatures around 350 degrees C and is above 80% for bonding...

  14. Humanitarian Cleft Lip/Palate Surgeries in Buddhist Thailand and Neighboring Countries.

    Science.gov (United States)

    Uemura, Tetsuji; Preeyanont, Piyoros; Udnoon, Sopridee

    2015-06-01

    This study evaluates surgeries done on patients with cleft lip and/or palate in Thailand and its neighboring countries from 1988 to 2008. This 21-year-long volunteer surgical mission was sponsored by Duang-Kaew Foundation, a volunteer organization. Countries involved, besides Thailand, were Vietnam, Myanmar, Laos, Cambodia, China, Sri Lanka, Bhutan, and India. The same surgical method for primary and secondary repair of lip and/or palate was used throughout: Onizuka method by single surgeon, the second author mainly. We assessed, by way of the patients' medical records including their background, the results of surgeries. The healing rates and complication rates associated with patients for primary and secondary repair of lip and/or palate. The study consisted of a total of 6832 patients: 3120 with cleft lip (CL); 2190 with cleft palate (CP); and 1522 with cleft lip and palate (CLP). Their primary cases were 675 (CL), 799 (CP), and 301 (CLP). All CP operations were done under general anesthesia. Of the CL surgeries, 10% of adult cases were done under local anesthesia. Of all the patients, 78%, or 5329, had one surgery; and 22%, or 1503, had 2 or more surgeries. Good healing was seen in 73.3%, whereas wound infection was noted in 2.0% and healing by second intention was in 1.2% of all cases. It is important that the Onizuka method was the only method used in all the countries throughout the mission period. The method has an advantage over other methods in that its design is simple enough so that even a beginning plastic surgeon can easily master, and operative results are constantly good regardless of who did the operation. The Duang-Kaew Foundation's long-term surgical program helped reduce the number of untreated patients to manageable levels for local health care providers in Thailand and neighboring countries for as long as 21 years.

  15. Lysenin Toxin Membrane Insertion Is pH-Dependent but Independent of Neighboring Lysenins.

    Science.gov (United States)

    Munguira, Ignacio L B; Takahashi, Hirohide; Casuso, Ignacio; Scheuring, Simon

    2017-11-07

    Pore-forming toxins form a family of proteins that act as virulence factors of pathogenic bacteria, but similar proteins are found in all kingdoms of life, including the vertebrate immune system. They are secreted as soluble monomers that oligomerize on target membranes in the so-called prepore state; after activation, they insert into the membrane and adopt the pore state. Lysenin is a pore-forming toxin from the earthworm Eisenida foetida, of which both the soluble and membrane-inserted structures are solved. However, the activation and membrane-insertion mechanisms have remained elusive. Here, we used high-speed atomic force microscopy to directly visualize the membrane-insertion mechanism. Changing the environmental pH from pH 7.5 to below pH 6.0 favored membrane insertion. We detected a short α-helix in the soluble structure that comprised three glutamic acids (Glu92, Glu94, and Glu97) that we hypothesized may represent a pH-sensor (as in similar toxins, e.g., Listeriolysin). Mutant lysenin still can form pores, but mutating these glutamic acids to glutamines rendered the toxin pH-insensitive. On the other hand, toxins in the pore state did not favor insertion of neighboring prepores; indeed, pore insertion breaks the hexagonal ordered domains of prepores and separates from neighboring molecules in the membrane. pH-dependent activation of toxins may represent a common feature of pore-forming toxins. High-speed atomic force microscopy with single-molecule resolution at high temporal resolution and the possibility of exchanging buffers during the experiments presents itself as a unique tool for the study of toxin-state conversion. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  16. Thyroid monitoring for residents of disaster-affected and neighboring areas

    International Nuclear Information System (INIS)

    Ito, Shigeki

    2014-01-01

    The devastating environmental contamination caused by the nuclear disaster at the Fukushima Daiichi Nuclear Power Station of The Tokyo Electric Power Company is exposing the residents of the disaster-affected areas to health risks attributable to radiation exposure, and fear of the development of 131 I-induced thyroid cancer, which is a stochastic effect of radiation and is particularly high. As part of the response to nuclear disasters by the government of the municipality where the nuclear power station is located and in operation and by the governments of neighboring municipalities, it is necessary to conduct thyroid monitoring for the purpose of alleviating the fears of residents of the disaster-affected areas as well as those living in the contaminated, even if only slightly, neighboring areas (local residents). This health monitoring needs to be implemented without delay in the case of a disaster along with dissemination of a portable type thyroid monitoring system available at evacuation centers, etc. for assessing thyroid exposure doses. The establishment of a system for developing personnel ready to perform monitoring is also essential. Assessing thyroid exposure doses is indispensable as a means of assuring local residents not only of safety but also of security from the risks of radiation. To date, contamination has not been detected in people, except for residents contaminated by a large amount of iodine, by employing the mobile type of thyroid monitoring system. However, when local residents seeking security desire thyroid monitoring, it is preferable that a portable type simplified thyroid monitoring system be used as a means of ensuring security against radiation. (author)

  17. Wildflower Plantings Do Not Compete With Neighboring Almond Orchards for Pollinator Visits.

    Science.gov (United States)

    Lundin, Ola; Ward, Kimiora L; Artz, Derek R; Boyle, Natalie K; Pitts-Singer, Theresa L; Williams, Neal M

    2017-06-01

    The engineering of flowering agricultural field borders has emerged as a research and policy priority to mitigate threats to pollinators. Studies have, however, rarely addressed the potential that flowering field borders might compete with neighboring crops for pollinator visits if they both are in bloom at the same time, despite this being a concern expressed by growers. We evaluated how wildflower plantings added to orchard borders in a large (512 ha) commercial almond orchard affected honey bee and wild bee visitation to orchard borders and the crop. The study was conducted over two consecutive seasons using three large (0.48 ha) wildflower plantings paired with control orchard borders in a highly simplified agricultural landscape in California. Honey bee (Apis mellifera L.) and wild bee visitation to wildflower plots were at least an order of magnitude higher than to control plots, but increased honey bee visitation to wildflower plots did not lead to any detectable shifts in honey bee visitation to almond flowers in the neighboring orchard. Wild bees were rarely observed visiting almond flowers irrespective of border treatment, indicating a limited short-term potential for augmenting crop pollination using wild bees in highly simplified agricultural landscapes. Although further studies are warranted on bee visitation and crop yield from spatially independent orchards, this study indicates that growers can support bees with alternative forage in almond orchards without risking competition between the wildflower plantings and the crop. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Improved Fuzzy K-Nearest Neighbor Using Modified Particle Swarm Optimization

    Science.gov (United States)

    Jamaluddin; Siringoringo, Rimbun

    2017-12-01

    Fuzzy k-Nearest Neighbor (FkNN) is one of the most powerful classification methods. The presence of fuzzy concepts in this method successfully improves its performance on almost all classification issues. The main drawbackof FKNN is that it is difficult to determine the parameters. These parameters are the number of neighbors (k) and fuzzy strength (m). Both parameters are very sensitive. This makes it difficult to determine the values of ‘m’ and ‘k’, thus making FKNN difficult to control because no theories or guides can deduce how proper ‘m’ and ‘k’ should be. This study uses Modified Particle Swarm Optimization (MPSO) to determine the best value of ‘k’ and ‘m’. MPSO is focused on the Constriction Factor Method. Constriction Factor Method is an improvement of PSO in order to avoid local circumstances optima. The model proposed in this study was tested on the German Credit Dataset. The test of the data/The data test has been standardized by UCI Machine Learning Repository which is widely applied to classification problems. The application of MPSO to the determination of FKNN parameters is expected to increase the value of classification performance. Based on the experiments that have been done indicating that the model offered in this research results in a better classification performance compared to the Fk-NN model only. The model offered in this study has an accuracy rate of 81%, while. With using Fk-NN model, it has the accuracy of 70%. At the end is done comparison of research model superiority with 2 other classification models;such as Naive Bayes and Decision Tree. This research model has a better performance level, where Naive Bayes has accuracy 75%, and the decision tree model has 70%

  19. Tularemia, a re-emerging infectious disease in Iran and neighboring countrie

    Science.gov (United States)

    Zargar, Afsaneh; Maurin, Max; Mostafavi, Ehsan

    2015-01-01

    OBJECTIVES: Tularemia is a zoonotic disease transmitted by direct contact with infected animals and through arthropod bites, inhalation of contaminated aerosols, ingestion of contaminated meat or water, and skin contact with any infected material. It is widespread throughout the northern hemisphere, including Iran and its neighbors to the north, northeast, and northwest. METHODS: In this paper, the epidemiology of tularemia as a re-emerging infectious disease in the world with a focus on Iran and the neighboring countries is reviewed. RESULTS: In Iran, positive serological tests were first reported in 1973, in wildlife and domestic livestock in the northwestern and southeastern parts of the country. The first human case was reported in 1980 in the southwest of Iran, and recent studies conducted among at-risk populations in the western, southeastern, and southwestern parts of Iran revealed seroprevalences of 14.4, 6.52, and 6%, respectively. CONCLUSIONS: Several factors may explain the absence of reported tularemia cases in Iran since 1980. Tularemia may be underdiagnosed in Iran because Francisella tularensis subspecies holarctica is likely to be the major etiological agent and usually causes mild to moderately severe disease. Furthermore, tularemia is not a disease extensively studied in the medical educational system in Iran, and empirical therapy may be effective in many cases. Finally, it should be noted that laboratories capable of diagnosing tularemia have only been established in the last few years. Since both recent and older studies have consistently found tularemia antibodies in humans and animals, the surveillance of this disease should receive more attention. In particular, it would be worthwhile for clinical researchers to confirm tularemia cases more often by isolating F. tularensis from infected humans and animals. PMID:25773439

  20. Rapid and Robust Cross-Correlation-Based Seismic Phase Identification Using an Approximate Nearest Neighbor Method

    Science.gov (United States)

    Tibi, R.; Young, C. J.; Gonzales, A.; Ballard, S.; Encarnacao, A. V.

    2016-12-01

    The matched filtering technique involving the cross-correlation of a waveform of interest with archived signals from a template library has proven to be a powerful tool for detecting events in regions with repeating seismicity. However, waveform correlation is computationally expensive, and therefore impractical for large template sets unless dedicated distributed computing hardware and software are used. In this study, we introduce an Approximate Nearest Neighbor (ANN) approach that enables the use of very large template libraries for waveform correlation without requiring a complex distributed computing system. Our method begins with a projection into a reduced dimensionality space based on correlation with a randomized subset of the full template archive. Searching for a specified number of nearest neighbors is accomplished by using randomized K-dimensional trees. We used the approach to search for matches to each of 2700 analyst-reviewed signal detections reported for May 2010 for the IMS station MKAR. The template library in this case consists of a dataset of more than 200,000 analyst-reviewed signal detections for the same station from 2002-2014 (excluding May 2010). Of these signal detections, 60% are teleseismic first P, and 15% regional phases (Pn, Pg, Sn, and Lg). The analyses performed on a standard desktop computer shows that the proposed approach performs the search of the large template libraries about 20 times faster than the standard full linear search, while achieving recall rates greater than 80%, with the recall rate increasing for higher correlation values. To decide whether to confirm a match, we use a hybrid method involving a cluster approach for queries with two or more matches, and correlation score for single matches. Of the signal detections that passed our confirmation process, 52% were teleseismic first P, and 30% were regional phases.

  1. A Regression-based K nearest neighbor algorithm for gene function prediction from heterogeneous data

    Directory of Open Access Journals (Sweden)

    Ruzzo Walter L

    2006-03-01

    Full Text Available Abstract Background As a variety of functional genomic and proteomic techniques become available, there is an increasing need for functional analysis methodologies that integrate heterogeneous data sources. Methods In this paper, we address this issue by proposing a general framework for gene function prediction based on the k-nearest-neighbor (KNN algorithm. The choice of KNN is motivated by its simplicity, flexibility to incorporate different data types and adaptability to irregular feature spaces. A weakness of traditional KNN methods, especially when handling heterogeneous data, is that performance is subject to the often ad hoc choice of similarity metric. To address this weakness, we apply regression methods to infer a similarity metric as a weighted combination of a set of base similarity measures, which helps to locate the neighbors that are most likely to be in the same class as the target gene. We also suggest a novel voting scheme to generate confidence scores that estimate the accuracy of predictions. The method gracefully extends to multi-way classification problems. Results We apply this technique to gene function prediction according to three well-known Escherichia coli classification schemes suggested by biologists, using information derived from microarray and genome sequencing data. We demonstrate that our algorithm dramatically outperforms the naive KNN methods and is competitive with support vector machine (SVM algorithms for integrating heterogenous data. We also show that by combining different data sources, prediction accuracy can improve significantly. Conclusion Our extension of KNN with automatic feature weighting, multi-class prediction, and probabilistic inference, enhance prediction accuracy significantly while remaining efficient, intuitive and flexible. This general framework can also be applied to similar classification problems involving heterogeneous datasets.

  2. Detection of Burkholderia pseudomallei O-antigen serotypes in near-neighbor species

    Directory of Open Access Journals (Sweden)

    Stone Joshua K

    2012-11-01

    Full Text Available Abstract Background Burkholderia pseudomallei is the etiological agent of melioidosis and a CDC category B select agent with no available effective vaccine. Previous immunizations in mice have utilized the lipopolysaccharide (LPS as a potential vaccine target because it is known as one of the most important antigenic epitopes in B. pseudomallei. Complicating this strategy are the four different B. pseudomallei LPS O-antigen types: A, B, B2, and rough. Sero-crossreactivity is common among O-antigens of Burkholderia species. Here, we identified the presence of multiple B. pseudomallei O-antigen types and sero-crossreactivity in its near-neighbor species. Results PCR screening of O-antigen biosynthesis genes, phenotypic characterization using SDS-PAGE, and immunoblot analysis showed that majority of B. mallei and B. thailandensis strains contained the typical O-antigen type A. In contrast, most of B. ubonensis and B. thailandensis-like strains expressed the atypical O-antigen types B and B2, respectively. Most B. oklahomensis strains expressed a distinct and non-seroreactive O-antigen type, except strain E0147 which expressed O-antigen type A. O-antigen type B2 was also detected in B. thailandensis 82172, B. ubonensis MSMB108, and Burkholderia sp. MSMB175. Interestingly, B. thailandensis-like MSMB43 contained a novel serotype B positive O-antigen. Conclusions This study expands the number of species which express B. pseudomallei O-antigen types. Further work is required to elucidate the full structures and how closely these are to the B. pseudomallei O-antigens, which will ultimately determine the efficacy of the near-neighbor B serotypes for vaccine development.

  3. Distance-Constraint k-Nearest Neighbor Searching in Mobile Sensor Networks.

    Science.gov (United States)

    Han, Yongkoo; Park, Kisung; Hong, Jihye; Ulamin, Noor; Lee, Young-Koo

    2015-07-27

    The κ-Nearest Neighbors ( κNN) query is an important spatial query in mobile sensor networks. In this work we extend κNN to include a distance constraint, calling it a l-distant κ-nearest-neighbors (l-κNN) query, which finds the κ sensor nodes nearest to a query point that are also at or greater distance from each other. The query results indicate the objects nearest to the area of interest that are scattered from each other by at least distance l. The l-κNN query can be used in most κNN applications for the case of well distributed query results. To process an l-κNN query, we must discover all sets of κNN sensor nodes and then find all pairs of sensor nodes in each set that are separated by at least a distance l. Given the limited battery and computing power of sensor nodes, this l-κNN query processing is problematically expensive in terms of energy consumption. In this paper, we propose a greedy approach for l-κNN query processing in mobile sensor networks. The key idea of the proposed approach is to divide the search space into subspaces whose all sides are l. By selecting κ sensor nodes from the other subspaces near the query point, we guarantee accurate query results for l-κNN. In our experiments, we show that the proposed method exhibits superior performance compared with a post-processing based method using the κNN query in terms of energy efficiency, query latency, and accuracy.

  4. Silicon-micromachined microchannel plates

    International Nuclear Information System (INIS)

    Beetz, Charles P.; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R.

    2000-01-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of ∼0.5 to ∼25 μm, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposited or nucleated in the channels or the first strike surface. Results on resistivity, secondary emission and gain are presented

  5. Implantation damage in silicon devices

    International Nuclear Information System (INIS)

    Nicholas, K.H.

    1977-01-01

    Ion implantation, is an attractive technique for producing doped layers in silicon devices but the implantation process involves disruption of the lattice and defects are formed, which can degrade device properties. Methods of minimizing such damage are discussed and direct comparisons made between implantation and diffusion techniques in terms of defects in the final devices and the electrical performance of the devices. Defects are produced in the silicon lattice during implantation but they are annealed to form secondary defects even at room temperature. The annealing can be at a low temperature ( 0 C) when migration of defects in silicon in generally small, or at high temperature when they can grow well beyond the implanted region. The defect structures can be complicated by impurity atoms knocked into the silicon from surface layers by the implantation. Defects can also be produced within layers on top of the silicon and these can be very important in device fabrication. In addition to affecting the electrical properties of the final device, defects produced during fabrication may influence the chemical properties of the materials. The use of these properties to improve devices are discussed as well as the degradation they can cause. (author)

  6. Detecting PM2.5's Correlations between Neighboring Cities Using a Time-Lagged Cross-Correlation Coefficient.

    Science.gov (United States)

    Wang, Fang; Wang, Lin; Chen, Yuming

    2017-08-31

    In order to investigate the time-dependent cross-correlations of fine particulate (PM2.5) series among neighboring cities in Northern China, in this paper, we propose a new cross-correlation coefficient, the time-lagged q-L dependent height crosscorrelation coefficient (denoted by p q (τ, L)), which incorporates the time-lag factor and the fluctuation amplitude information into the analogous height cross-correlation analysis coefficient. Numerical tests are performed to illustrate that the newly proposed coefficient ρ q (τ, L) can be used to detect cross-correlations between two series with time lags and to identify different range of fluctuations at which two series possess cross-correlations. Applying the new coefficient to analyze the time-dependent cross-correlations of PM2.5 series between Beijing and the three neighboring cities of Tianjin, Zhangjiakou, and Baoding, we find that time lags between the PM2.5 series with larger fluctuations are longer than those between PM2.5 series withsmaller fluctuations. Our analysis also shows that cross-correlations between the PM2.5 series of two neighboring cities are significant and the time lags between two PM2.5 series of neighboring cities are significantly non-zero. These findings providenew scientific support on the view that air pollution in neighboring cities can affect one another not simultaneously but with a time lag.

  7. Incorporating the information from direct and indirect neighbors into fitness evaluation enhances the cooperation in the social dilemmas

    International Nuclear Information System (INIS)

    Hu, Menglong; Wang, Juan; Kong, Lingcong; An, Kang; Bi, Tao; Guo, Baohong; Dong, Enzeng

    2015-01-01

    Highlights: •A novel fitness evaluation method integrating environmental information is presented. •The introduction of neighbors’ payoff favors the promotion of cooperation in the PDG. •The role of direct neighbors becomes much more prominent. •In the SDG, the cooperative behavior is also improved by this new mechanism. -- Abstract: We propose an improved fitness evaluation method to investigate the evolution of cooperation in the spatial social dilemmas. In our model, a focal player’s fitness is calculated as the linear combination of his own payoff, the average payoffs of direct and indirect neighbors in which two independent selection parameters (α and β) are used to control the proportion of various payoff contribution to the current fitness. Then, the fitness-based strategy update rule is still Fermi-like, and asynchronous update is adopted here. A large plethora of numerical simulations are performed to validate the behaviors of the current model, and the results unambiguously demonstrate that the cooperation level is greatly enhanced by introducing the payoffs from the surrounding players. In particular, the influence of direct neighbors become more evident when compared with indirect neighbors since the correlation between focal players and their direct neighbors is much closer. Current outcomes are significant for us to further illustrate the origin and emergence of cooperation within a wide variety of natural and man-made systems

  8. Flexible Thermoelectric Generators on Silicon Fabric

    KAUST Repository

    Sevilla, Galo T.

    2012-01-01

    In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart

  9. Porous silicon carbide (SIC) semiconductor device

    Science.gov (United States)

    Shor, Joseph S. (Inventor); Kurtz, Anthony D. (Inventor)

    1996-01-01

    Porous silicon carbide is fabricated according to techniques which result in a significant portion of nanocrystallites within the material in a sub 10 nanometer regime. There is described techniques for passivating porous silicon carbide which result in the fabrication of optoelectronic devices which exhibit brighter blue luminescence and exhibit improved qualities. Based on certain of the techniques described porous silicon carbide is used as a sacrificial layer for the patterning of silicon carbide. Porous silicon carbide is then removed from the bulk substrate by oxidation and other methods. The techniques described employ a two-step process which is used to pattern bulk silicon carbide where selected areas of the wafer are then made porous and then the porous layer is subsequently removed. The process to form porous silicon carbide exhibits dopant selectivity and a two-step etching procedure is implemented for silicon carbide multilayers.

  10. The LHCb Silicon Tracker Project

    International Nuclear Information System (INIS)

    Agari, M.; Bauer, C.; Baumeister, D.; Blouw, J.; Hofmann, W.; Knoepfle, K.T.; Loechner, S.; Schmelling, M.; Pugatch, V.; Bay, A.; Carron, B.; Frei, R.; Jiminez-Otero, S.; Tran, M.-T.; Voss, H.; Adeva, B.; Esperante, D.; Lois, C.; Vasquez, P.; Bernhard, R.P.; Bernet, R.; Ermoline, Y.; Gassner, J.; Koestner, S.; Lehner, F.; Needham, M.; Siegler, M.; Steinkamp, O.; Straumann, U.; Vollhardt, A.; Volyanskyy, D.

    2006-01-01

    Two silicon strip detectors, the Trigger Tracker(TT) and the Inner Tracker(Italy) will be constructed for the LHCb experiment. Transverse momentum information extracted from the TT will be used in the Level 1 trigger. The IT is part of the main tracking system behind the magnet. Both silicon detectors will be read out using a custom-developed chip by the ASIC lab in Heidelberg. The signal-over-noise behavior and performance of various geometrical designs of the silicon sensors, in conjunction with the Beetle read-out chip, have been extensively studied in test beam experiments. Results from those experiments are presented, and have been used in the final choice of sensor geometry

  11. A silicon tracker for Christmas

    CERN Multimedia

    2008-01-01

    The CMS experiment installed the world’s largest silicon tracker just before Christmas. Marcello Mannelli: physicist and deputy CMS project leader, and Alan Honma, physicist, compare two generations of tracker: OPAL for the LEP (at the front) and CMS for the LHC (behind). There is quite a difference between 1m2 and 205m2.. CMS received an early Christmas present on 18 December when the silicon tracker was installed in the heart of the CMS magnet. The CMS tracker team couldn’t have hoped for a better present. Carefully wrapped in shiny plastic, the world’s largest silicon tracker arrived at Cessy ready for installation inside the CMS magnet on 18 December. This rounded off the year for CMS with a major event, the crowning touch to ten years of work on the project by over five hundred scientists and engineers. "Building a scientific instrument of this size and complexity is a huge technical a...

  12. Belle II silicon vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, K. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Aihara, H. [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Angelini, C. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Aziz, T.; Babu, V. [Tata Institute of Fundamental Research, Mumbai 400005 (India); Bacher, S. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Bahinipati, S. [Indian Institute of Technology Bhubaneswar, Satya Nagar (India); Barberio, E.; Baroncelli, Ti.; Baroncelli, To. [School of Physics, University of Melbourne, Melbourne, Victoria 3010 (Australia); Basith, A.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Batignani, G. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bauer, A. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Behera, P.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Bergauer, T. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Bettarini, S. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bhuyan, B. [Indian Institute of Technology Guwahati, Assam 781039 (India); Bilka, T. [Faculty of Mathematics and Physics, Charles University, 121 16 Prague (Czech Republic); Bosi, F. [INFN Sezione di Pisa, I-56127 Pisa (Italy); Bosisio, L. [Dipartimento di Fisica, Università di Trieste, I-34127 Trieste (Italy); INFN Sezione di Trieste, I-34127 Trieste (Italy); and others

    2016-09-21

    The Belle II experiment at the SuperKEKB collider in Japan is designed to indirectly probe new physics using approximately 50 times the data recorded by its predecessor. An accurate determination of the decay-point position of subatomic particles such as beauty and charm hadrons as well as a precise measurement of low-momentum charged particles will play a key role in this pursuit. These will be accomplished by an inner tracking device comprising two layers of pixelated silicon detector and four layers of silicon vertex detector based on double-sided microstrip sensors. We describe herein the design, prototyping and construction efforts of the Belle-II silicon vertex detector.

  13. The CMS silicon strip tracker

    International Nuclear Information System (INIS)

    Focardi, E.; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Bartalini, P.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borrello, L.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Civinini, C.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; Demaria, N.; De Palma, M.; Dell'Orso, R.; Marina, R. Della; Dutta, S.; Eklund, C.; Elliott-Peisert, A.; Feld, L.; Fiore, L.; French, M.; Freudenreich, K.; Fuertjes, A.; Giassi, A.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammerstrom, R.; Hebbeker, T.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B. Mc; Meschini, M.; Messineo, A.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Raffaelli, F.; Raso, G.; Raymond, M.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Skog, K.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Wang, Y.; Watts, S.; Wittmer, B.

    1999-01-01

    The Silicon Strip Tracker (SST) is the intermediate part of the CMS Central Tracker System. SST is based on microstrip silicon devices and in combination with pixel detectors and the Microstrip Gas Chambers aims at performing pattern recognition, track reconstruction and momentum measurements for all tracks with p T ≥2 GeV/c originating from high luminosity interactions at √s=14 TeV at LHC. We aim at exploiting the advantages and the physics potential of the precise tracking performance provided by the microstrip silicon detectors on a large scale apparatus and in a much more difficult environment than ever. In this paper we describe the actual SST layout and the readout system. (author)

  14. Waveguide silicon nitride grating coupler

    Science.gov (United States)

    Litvik, Jan; Dolnak, Ivan; Dado, Milan

    2016-12-01

    Grating couplers are one of the most used elements for coupling of light between optical fibers and photonic integrated components. Silicon-on-insulator platform provides strong confinement of light and allows high integration. In this work, using simulations we have designed a broadband silicon nitride surface grating coupler. The Fourier-eigenmode expansion and finite difference time domain methods are utilized in design optimization of grating coupler structure. The fully, single etch step grating coupler is based on a standard silicon-on-insulator wafer with 0.55 μm waveguide Si3N4 layer. The optimized structure at 1550 nm wavelength yields a peak coupling efficiency -2.6635 dB (54.16%) with a 1-dB bandwidth up to 80 nm. It is promising way for low-cost fabrication using complementary metal-oxide- semiconductor fabrication process.

  15. The effect of silicon crystallographic orientation on the formation of silicon nanoclusters during anodic electrochemical etching

    International Nuclear Information System (INIS)

    Timokhov, D. F.; Timokhov, F. P.

    2009-01-01

    Possible ways for increasing the photoluminescence quantum yield of porous silicon layers have been investigated. The effect of the anodization parameters on the photoluminescence properties for porous silicon layers formed on silicon substrates with different crystallographic orientations was studied. The average diameters for silicon nanoclusters are calculated from the photoluminescence spectra of porous silicon. The influence of the substrate crystallographic orientation on the photoluminescence quantum yield of porous silicon is revealed. A model explaining the effect of the substrate orientation on the photoluminescence properties for the porous silicon layers formed by anode electrochemical etching is proposed.

  16. Surface Effects in Segmented Silicon Sensors

    OpenAIRE

    Kopsalis, Ioannis

    2017-01-01

    Silicon detectors in Photon Science and Particle Physics require silicon sensors with very demanding specifications. New accelerators like the European X-ray Free Electron Laser (EuXFEL) and the High Luminosity upgrade of the Large Hadron Collider (HL-LHC), pose new challenges for silicon sensors, especially with respect to radiation hardness. High radiation doses and fluences damage the silicon crystal and the SiO2 layers at the surface, thus changing the sensor properties and limiting their...

  17. Semiconducting silicon nanowires for biomedical applications

    CERN Document Server

    Coffer, JL

    2014-01-01

    Biomedical applications have benefited greatly from the increasing interest and research into semiconducting silicon nanowires. Semiconducting Silicon Nanowires for Biomedical Applications reviews the fabrication, properties, and applications of this emerging material. The book begins by reviewing the basics, as well as the growth, characterization, biocompatibility, and surface modification, of semiconducting silicon nanowires. It goes on to focus on silicon nanowires for tissue engineering and delivery applications, including cellular binding and internalization, orthopedic tissue scaffol

  18. Silicon Photonics Cloud (SiCloud)

    DEFF Research Database (Denmark)

    DeVore, P. T. S.; Jiang, Y.; Lynch, M.

    2015-01-01

    Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths.......Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths....

  19. Silicon photonics for multicore fiber communication

    DEFF Research Database (Denmark)

    Ding, Yunhong; Kamchevska, Valerija; Dalgaard, Kjeld

    2016-01-01

    We review our recent work on silicon photonics for multicore fiber communication, including multicore fiber fan-in/fan-out, multicore fiber switches towards reconfigurable optical add/drop multiplexers. We also present multicore fiber based quantum communication using silicon devices.......We review our recent work on silicon photonics for multicore fiber communication, including multicore fiber fan-in/fan-out, multicore fiber switches towards reconfigurable optical add/drop multiplexers. We also present multicore fiber based quantum communication using silicon devices....

  20. Simulation of atomistic processes during silicon oxidation

    OpenAIRE

    Bongiorno, Angelo

    2003-01-01

    Silicon dioxide (SiO2) films grown on silicon monocrystal (Si) substrates form the gate oxides in current Si-based microelectronics devices. The understanding at the atomic scale of both the silicon oxidation process and the properties of the Si(100)-SiO2 interface is of significant importance in state-of-the-art silicon microelectronics manufacturing. These two topics are intimately coupled and are both addressed in this theoretical investigation mainly through first-principles calculations....

  1. Thermophysical spectroscopy of defect states in silicon

    International Nuclear Information System (INIS)

    Igamberdyev, Kh.T.; Mamadalimov, A.T.; Khabibullaev, P.K.

    1989-01-01

    The present work deals with analyzing the possibilities of using the non-traditional thermophysical methods to study a defect structure in silicon. For this purpose, the temperature dependences of thermophysical properties of defect silicon are investigated. A number of new, earlier unknown physical phenomena in silicon are obtained, and their interpretation has enabled one to establish the main physical mechanisms of formation of deep defect states in silicon

  2. Laser wafering for silicon solar

    International Nuclear Information System (INIS)

    Friedmann, Thomas Aquinas; Sweatt, William C.; Jared, Bradley Howell

    2011-01-01

    Current technology cuts solar Si wafers by a wire saw process, resulting in 50% 'kerf' loss when machining silicon from a boule or brick into a wafer. We want to develop a kerf-free laser wafering technology that promises to eliminate such wasteful wire saw processes and achieve up to a ten-fold decrease in the g/W p (grams/peak watt) polysilicon usage from the starting polysilicon material. Compared to today's technology, this will also reduce costs (∼20%), embodied energy, and green-house gas GHG emissions (∼50%). We will use short pulse laser illumination sharply focused by a solid immersion lens to produce subsurface damage in silicon such that wafers can be mechanically cleaved from a boule or brick. For this concept to succeed, we will need to develop optics, lasers, cleaving, and high throughput processing technologies capable of producing wafers with thicknesses < 50 (micro)m with high throughput (< 10 sec./wafer). Wafer thickness scaling is the 'Moore's Law' of silicon solar. Our concept will allow solar manufacturers to skip entire generations of scaling and achieve grid parity with commercial electricity rates. Yet, this idea is largely untested and a simple demonstration is needed to provide credibility for a larger scale research and development program. The purpose of this project is to lay the groundwork to demonstrate the feasibility of laser wafering. First, to design and procure on optic train suitable for producing subsurface damage in silicon with the required damage and stress profile to promote lateral cleavage of silicon. Second, to use an existing laser to produce subsurface damage in silicon, and third, to characterize the damage using scanning electron microscopy and confocal Raman spectroscopy mapping.

  3. Laser wafering for silicon solar.

    Energy Technology Data Exchange (ETDEWEB)

    Friedmann, Thomas Aquinas; Sweatt, William C.; Jared, Bradley Howell

    2011-03-01

    Current technology cuts solar Si wafers by a wire saw process, resulting in 50% 'kerf' loss when machining silicon from a boule or brick into a wafer. We want to develop a kerf-free laser wafering technology that promises to eliminate such wasteful wire saw processes and achieve up to a ten-fold decrease in the g/W{sub p} (grams/peak watt) polysilicon usage from the starting polysilicon material. Compared to today's technology, this will also reduce costs ({approx}20%), embodied energy, and green-house gas GHG emissions ({approx}50%). We will use short pulse laser illumination sharply focused by a solid immersion lens to produce subsurface damage in silicon such that wafers can be mechanically cleaved from a boule or brick. For this concept to succeed, we will need to develop optics, lasers, cleaving, and high throughput processing technologies capable of producing wafers with thicknesses < 50 {micro}m with high throughput (< 10 sec./wafer). Wafer thickness scaling is the 'Moore's Law' of silicon solar. Our concept will allow solar manufacturers to skip entire generations of scaling and achieve grid parity with commercial electricity rates. Yet, this idea is largely untested and a simple demonstration is needed to provide credibility for a larger scale research and development program. The purpose of this project is to lay the groundwork to demonstrate the feasibility of laser wafering. First, to design and procure on optic train suitable for producing subsurface damage in silicon with the required damage and stress profile to promote lateral cleavage of silicon. Second, to use an existing laser to produce subsurface damage in silicon, and third, to characterize the damage using scanning electron microscopy and confocal Raman spectroscopy mapping.

  4. Vertical integration of high-Q silicon nitride microresonators into silicon-on-insulator platform.

    Science.gov (United States)

    Li, Qing; Eftekhar, Ali A; Sodagar, Majid; Xia, Zhixuan; Atabaki, Amir H; Adibi, Ali

    2013-07-29

    We demonstrate a vertical integration of high-Q silicon nitride microresonators into the silicon-on-insulator platform for applications at the telecommunication wavelengths. Low-loss silicon nitride films with a thickness of 400 nm are successfully grown, enabling compact silicon nitride microresonators with ultra-high intrinsic Qs (~ 6 × 10(6) for 60 μm radius and ~ 2 × 10(7) for 240 μm radius). The coupling between the silicon nitride microresonator and the underneath silicon waveguide is based on evanescent coupling with silicon dioxide as buffer. Selective coupling to a desired radial mode of the silicon nitride microresonator is also achievable using a pulley coupling scheme. In this work, a 60-μm-radius silicon nitride microresonator has been successfully integrated into the silicon-on-insulator platform, showing a single-mode operation with an intrinsic Q of 2 × 10(6).

  5. The N400 as a snapshot of interactive processing: evidence from regression analyses of orthographic neighbor and lexical associate effects

    Science.gov (United States)

    Laszlo, Sarah; Federmeier, Kara D.

    2010-01-01

    Linking print with meaning tends to be divided into subprocesses, such as recognition of an input's lexical entry and subsequent access of semantics. However, recent results suggest that the set of semantic features activated by an input is broader than implied by a view wherein access serially follows recognition. EEG was collected from participants who viewed items varying in number and frequency of both orthographic neighbors and lexical associates. Regression analysis of single item ERPs replicated past findings, showing that N400 amplitudes are greater for items with more neighbors, and further revealed that N400 amplitudes increase for items with more lexical associates and with higher frequency neighbors or associates. Together, the data suggest that in the N400 time window semantic features of items broadly related to inputs are active, consistent with models in which semantic access takes place in parallel with stimulus recognition. PMID:20624252

  6. Effect of electrode design on crosstalk between neighboring organic field-effect transistors based on one single crystal

    Science.gov (United States)

    Li, Mengjie; Tang, Qingxin; Tong, Yanhong; Zhao, Xiaoli; Zhou, Shujun; Liu, Yichun

    2018-03-01

    The design of high-integration organic circuits must be such that the interference between neighboring devices is eliminated. Here, rubrene crystals were used to study the effect of the electrode design on crosstalk between neighboring organic field-effect transistors (OFETs). Results show that a decreased source/drain interval and gate electrode width can decrease the diffraction distance of the current, and therefore can weaken the crosstalk. In addition, the inherent low carrier concentration in organic semiconductors can create a high-resistance barrier at the space between gate electrodes of neighboring devices, limiting or even eliminating the crosstalk as a result of the gate electrode width being smaller than the source/drain electrode width.

  7. Response properties of neighboring neurons in the auditory midbrain for pure-tone stimulation: a tetrode study.

    Science.gov (United States)

    Seshagiri, Chandran V; Delgutte, Bertrand

    2007-10-01

    The complex anatomical structure of the central nucleus of the inferior colliculus (ICC), the principal auditory nucleus in the midbrain, may provide the basis for functional organization of auditory information. To investigate this organization, we used tetrodes to record from neighboring neurons in the ICC of anesthetized cats and studied the similarity and difference among the responses of these neurons to pure-tone stimuli using widely used physiological characterizations. Consistent with the tonotopic arrangement of neurons in the ICC and reports of a threshold map, we found a high degree of correlation in the best frequencies (BFs) of neighboring neurons, which were mostly binaural beats. However, the characteristic phases (CPs) of neighboring neurons revealed a significant correlation. Because the CP is related to the neural mechanisms generating the ITD sensitivity, this result is consistent with segregation of inputs to the ICC from the lateral and medial superior olives.

  8. Large volume cryogenic silicon detectors

    International Nuclear Information System (INIS)

    Braggio, C.; Boscardin, M.; Bressi, G.; Carugno, G.; Corti, D.; Galeazzi, G.; Zorzi, N.

    2009-01-01

    We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm 3 , cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

  9. Large volume cryogenic silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Braggio, C. [Dipartimento di Fisica, Universita di Padova, via Marzolo 8, 35131 Padova (Italy); Boscardin, M. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy); Bressi, G. [INFN sez. di Pavia, via Bassi 6, 27100 Pavia (Italy); Carugno, G.; Corti, D. [INFN sez. di Padova, via Marzolo 8, 35131 Padova (Italy); Galeazzi, G. [INFN lab. naz. Legnaro, viale dell' Universita 2, 35020 Legnaro (Italy); Zorzi, N. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy)

    2009-12-15

    We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm{sup 3}, cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

  10. Production of silicon carbide bodies

    International Nuclear Information System (INIS)

    Parkinson, K.

    1981-01-01

    A body consisting essentially of a coherent mixture of silicon carbide and carbon for subsequent siliconising is produced by casting a slip comprising silicon carbide and carbon powders in a porous mould. Part of the surface of the body, particularly internal features, is formed by providing within the mould a core of a material which retains its shape while casting is in progress but is compressed by shrinkage of the cast body as it dries and is thereafter removable from the cast body. Materials which are suitable for the core are expanded polystyrene and gelatinous products of selected low elastic modulus. (author)

  11. High-End Silicon PDICs

    Directory of Open Access Journals (Sweden)

    H. Zimmermann

    2008-05-01

    Full Text Available An overview on integrated silicon photodiodes and photodiode integrated circuits (PDICs or optoelectronic integrated circuits (OEICs for optical storage systems (OSS and fiber receivers is given. It is demonstrated, that by using low-cost silicon technologies high-performance OEICs being true competitors for some III/V-semiconductor OEICs can be realized. OSS-OEICs with bandwidths of up to 380 MHz and fiber receivers with maximum data rates of up to 11 Gbps are described. Low-cost data comm receivers for plastic optical fibers (POF as well as new circuit concepts for OEICs and highly parallel optical receivers are described also in the following.

  12. Radiation damage in silicon detectors

    CERN Document Server

    Lindström, G

    2003-01-01

    Radiation damage effects in silicon detectors under severe hadron and gamma-irradiation are surveyed, focusing on bulk effects. Both macroscopic detector properties (reverse current, depletion voltage and charge collection) as also the underlying microscopic defect generation are covered. Basic results are taken from the work done in the CERN-RD48 (ROSE) collaboration updated by results of recent work. Preliminary studies on the use of dimerized float zone and Czochralski silicon as detector material show possible benefits. An essential progress in the understanding of the radiation-induced detector deterioration had recently been achieved in gamma irradiation, directly correlating defect analysis data with the macroscopic detector performance.

  13. High yield silicon carbide prepolymers

    International Nuclear Information System (INIS)

    Baney, R.H.

    1982-01-01

    Prepolymers which exhibit good handling properties, and are useful for preparing ceramics, silicon carbide ceramic materials and articles containing silicon carbide, are polysilanes consisting of 0 to 60 mole% (CH 3 ) 2 Si units and 40 to 100 mole% CH 3 Si units, all Si valences being satisfied by CH 3 groups, other Si atoms, or by H atoms, the latter amounting to 0.3 to 2.1 weight% of the polysilane. They are prepared by reducing the corresponding chloro- or bromo-polysilanes with at least the stoichiometric amount of a reducing agent, e.g. LiAlH 4 . (author)

  14. Surface Passivation for Silicon Heterojunction Solar Cells

    NARCIS (Netherlands)

    Deligiannis, D.

    2017-01-01

    Silicon heterojunction solar cells (SHJ) are currently one of the most promising solar cell technologies in the world. The SHJ solar cell is based on a crystalline silicon (c-Si) wafer, passivated on both sides with a thin intrinsic hydrogenated amorphous silicon (a-Si:H) layer. Subsequently, p-type

  15. Silicon Alloying On Aluminium Based Alloy Surface

    International Nuclear Information System (INIS)

    Suryanto

    2002-01-01

    Silicon alloying on surface of aluminium based alloy was carried out using electron beam. This is performed in order to enhance tribological properties of the alloy. Silicon is considered most important alloying element in aluminium alloy, particularly for tribological components. Prior to silicon alloying. aluminium substrate were painted with binder and silicon powder and dried in a furnace. Silicon alloying were carried out in a vacuum chamber. The Silicon alloyed materials were assessed using some techniques. The results show that silicon alloying formed a composite metal-non metal system in which silicon particles are dispersed in the alloyed layer. Silicon content in the alloyed layer is about 40% while in other place is only 10.5 %. The hardness of layer changes significantly. The wear properties of the alloying alloys increase. Silicon surface alloying also reduced the coefficient of friction for sliding against a hardened steel counter face, which could otherwise be higher because of the strong adhesion of aluminium to steel. The hardness of the silicon surface alloyed material dropped when it underwent a heating cycle similar to the ion coating process. Hence, silicon alloying is not a suitable choice for use as an intermediate layer for duplex treatment

  16. Highly efficient silicon light emitting diode

    NARCIS (Netherlands)

    Le Minh, P.; Holleman, J.; Wallinga, Hans

    2002-01-01

    In this paper, we describe the fabrication, using standard silicon processing techniques, of silicon light-emitting diodes (LED) that efficiently emit photons with energy around the silicon bandgap. The improved efficiency had been explained by the spatial confinement of charge carriers due to a

  17. Engineering piezoresistivity using biaxially strained silicon

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Richter, Jacob; Brandbyge, Mads

    2008-01-01

    of the piezocoefficient on temperature and dopant density is altered qualitatively for strained silicon. In particular, we find that a vanishing temperature coefficient may result for silicon with grown-in biaxial tensile strain. These results suggest that strained silicon may be used to engineer the iezoresistivity...

  18. Process Research on Polycrystalline Silicon Material (PROPSM)

    Science.gov (United States)

    Culik, J. S.; Wrigley, C. Y.

    1985-01-01

    Results of hydrogen-passivated polycrysalline silicon solar cell research are summarized. The short-circuit current of solar cells fabricated from large-grain cast polycrystalline silicon is nearly equivalent to that of single-crystal cells, which indicates long bulk minority-carrier diffusion length. Treatments with molecular hydrogen showed no effect on large-grain cast polycrystalline silicon solar cells.

  19. ePIXfab - The silicon photonics platform

    NARCIS (Netherlands)

    Khanna, A.; Drissi, Y.; Dumon, P.; Baets, R.; Absil, P.; Pozo Torres, J.M.; Lo Cascio, D.M.R.; Fournier, M.; Fedeli, J.M.; Fulbert, L.; Zimmermann, L.; Tillack, B.; Aalto, T.; O'Brien, P.; Deptuck, D.; Xu, J.; Gale, D.

    2013-01-01

    ePIXfab-The European Silicon Photonics Support Center continues to provide state-of-the-art silicon photonics solutions to academia and industry for prototyping and research. ePIXfab is a consortium of EU research centers providing diverse expertise in the silicon photonics food chain, from training

  20. Silicon-Based Nanoscale Composite Energetic Materials

    Science.gov (United States)

    2013-02-01

    1193-1211. 9. Krishnamohan, G., E.M. Kurian, and H.R. Rao, Thermal Analysis and Inverse Burning Rate Studies on Silicon-Potassium Nitrate System...reported in a journal paper and appears in the Appendix. Multiscale Nanoporous Silicon Combustion Introduction for nanoporous silicon effort While

  1. Process of preparing tritiated porous silicon

    Science.gov (United States)

    Tam, Shiu-Wing

    1997-01-01

    A process of preparing tritiated porous silicon in which porous silicon is equilibrated with a gaseous vapor containing HT/T.sub.2 gas in a diluent for a time sufficient for tritium in the gas phase to replace hydrogen present in the pore surfaces of the porous silicon.

  2. Porous silicon: X-rays sensitivity

    International Nuclear Information System (INIS)

    Gerstenmayer, J.L.; Vibert, Patrick; Mercier, Patrick; Rayer, Claude; Hyvernage, Michel; Herino, Roland; Bsiesy, Ahmad

    1994-01-01

    We demonstrate that high porosity anodically porous silicon is radioluminescent. Interests of this study are double. Firstly: is the construction of porous silicon X-rays detectors (imagers) possible? Secondly: is it necessary to protect silicon porous based optoelectronic systems from ionising radiations effects (spatial environment)? ((orig.))

  3. Formation and photoluminescence of "Cauliflower" silicon nanoparticles

    NARCIS (Netherlands)

    Tang, W.; Eilers, J.J.; Huis, van M.A.; Wang, D.; Schropp, R.E.I.; Vece, Di M.

    2015-01-01

    The technological advantages of silicon make silicon nanoparticles, which can be used as quantum dots in a tandem configuration, highly relevant for photovoltaics. However, producing a silicon quantum dot solar cell structure remains a challenge. Here we use a gas aggregation cluster source to

  4. Silicon vertex detector for superheavy elements identification

    Directory of Open Access Journals (Sweden)

    Bednarek A.

    2012-07-01

    Full Text Available Silicon vertex detector for superheavy elements (SHE identification has been proposed. It will be constructed using very thin silicon detectors about 5 μm thickness. Results of test of 7.3 μm four inch silicon strip detector (SSD with fission fragments and α particles emitted by 252Cf source are presented

  5. Implementation of the k -Neighbors Technique in a recommender algorithm for a purchasing system using NFC and Android

    Directory of Open Access Journals (Sweden)

    Oscar Arley Riveros

    2017-01-01

    Full Text Available Introduction: This paper aims to present the design of a mobile application involving NFC technology and a collaborative recommendation algorithm under the K-neighbors technique, allowing to observe personalized suggestions for each client. Objective: Design and develop a mobile application, using NFC technologies and K-Neighbors Technique in a recommendation algorithm, for a Procurement System. Methodology: The process followed for the design and development of the application focuses on: • Review of the state of the art in mobile shopping systems. • State-of-the-art construction in the use of NFC technology and AI techniques for recommending systems focused on K-Neighbors Algorithms • Proposed system design • Parameterization and implementation of the K-Neighbors Technique and integration of NFC Technology • Proposed System Implementation and Testing. Results: Among the results obtained are detailed: • Mobile application that integrates Android, NFC Technologies and a Technique of Algorithm Recommendation • Parameterization of the K-Neighbors Technique, to be used within the recommended algorithm. • Implementation of functional requirements that allow the generation of personalized recommendations for purchase to the user, user ratings Conclusions: The k-neighbors technique in a recommendation algorithm allows the client to provide a series of recommendations with a level of security, since this algorithm performs calculations taking into account multiple parameters and contrasts the results obtained for other users, finding the articles with a Greater degree of similarity with the customer profile. This algorithm starts from a sample of similar, complementary and other unrelated products, applying its respective formulation, we obtain that the recommendation is made only with the complementary products that obtained higher qualification; Making a big difference with most recommending systems on the market, which are limited to

  6. Indentation fatigue in silicon nitride, alumina and silicon carbide ...

    Indian Academy of Sciences (India)

    Unknown

    carbide ceramics. A K MUKHOPADHYAY. Central Glass and Ceramic Research Institute, Kolkata 700 032, India. Abstract. Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz.

  7. Ordered silicon nanostructures for silicon-based photonics devices

    Czech Academy of Sciences Publication Activity Database

    Fojtík, A.; Valenta, J.; Pelant, Ivan; Kálal, M.; Fiala, P.

    2007-01-01

    Roč. 5, Suppl. (2007), S250-S253 ISSN 1671-7694 R&D Projects: GA AV ČR IAA1010316 Grant - others:GA MŠk(CZ) ME 933 Institutional research plan: CEZ:AV0Z10100521 Keywords : nanocrystals * silicon * self-assembled monolayers Subject RIV: BM - Solid Matter Physics ; Magnetism

  8. Liquid phase epitaxial growth of silicon on porous silicon for photovoltaic applications

    International Nuclear Information System (INIS)

    Berger, S.; Quoizola, S.; Fave, A.; Kaminski, A.; Perichon, S.; Barbier, D.; Laugier, A.

    2001-01-01

    The aim of this experiment is to grow a thin silicon layer ( 2 atmosphere, and finally LPE silicon growth with different temperature profiles in order to obtain a silicon layer on the sacrificial porous silicon (p-Si). We observed a pyramidal growth on the surface of the (100) porous silicon but the coalescence was difficult to obtain. However, on a p-Si (111) oriented wafer, homogeneous layers were obtained. (orig.)

  9. 1366 Project Silicon: Reclaiming US Silicon PV Leadership

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Adam [1366 Technologies, Bedford, MA (United States)

    2016-02-16

    1366 Technologies’ Project Silicon addresses two of the major goals of the DOE’s PV Manufacturing Initiative Part 2 program: 1) How to reclaim a strong silicon PV manufacturing presence and; 2) How to lower the levelized cost of electricity (“LCOE”) for solar to $0.05-$0.07/kWh, enabling wide-scale U.S. market adoption. To achieve these two goals, US companies must commercialize disruptive, high-value technologies that are capable of rapid scaling, defensible from foreign competition, and suited for US manufacturing. These are the aims of 1366 Technologies Direct Wafer ™ process. The research conducted during Project Silicon led to the first industrial scaling of 1366’s Direct Wafer™ process – an innovative, US-friendly (efficient, low-labor content) manufacturing process that destroys the main cost barrier limiting silicon PV cost-reductions: the 35-year-old grand challenge of making quality wafers (40% of the cost of modules) without the cost and waste of sawing. The SunPath program made it possible for 1366 Technologies to build its demonstration factory, a key and critical step in the Company’s evolution. The demonstration factory allowed 1366 to build every step of the process flow at production size, eliminating potential risk and ensuring the success of the Company’s subsequent scaling for a 1 GW factory to be constructed in Western New York in 2016 and 2017. Moreover, the commercial viability of the Direct Wafer process and its resulting wafers were established as 1366 formed key strategic partnerships, gained entry into the $8B/year multi-Si wafer market, and installed modules featuring Direct Wafer products – the veritable proving grounds for the technology. The program also contributed to the development of three Generation 3 Direct Wafer furnaces. These furnaces are the platform for copying intelligently and preparing our supply chain – large-scale expansion will not require a bigger machine but more machines. SunPath filled the

  10. On the difference in oscillator strengths of inner shell excitations in noble gases and their alkali neighbors

    International Nuclear Information System (INIS)

    Amusia, M.Y.; Baltenkov, A.S.; Zhuravleva, G.I.

    1995-01-01

    It is demonstrated that the oscillator strength of resonant inner-shell excitation in a noble gas atom is considerably smaller than that in its alkali neighbor because in the latter case the effective charge acting upon excited electron is much bigger. With increase of the excitation's principal quantum number the difference between line intensities in noble gases and their alkali neighbors rapidly disappears. The calculations are performed in the Hartree-Fock approximation and with inclusion of rearrangement effects due to inner vacancy creation and its Auger decay. A paper has been submitted for publication

  11. Elliptic Painlevé equations from next-nearest-neighbor translations on the E_8^{(1)} lattice

    Science.gov (United States)

    Joshi, Nalini; Nakazono, Nobutaka

    2017-07-01

    The well known elliptic discrete Painlevé equation of Sakai is constructed by a standard translation on the E_8(1) lattice, given by nearest neighbor vectors. In this paper, we give a new elliptic discrete Painlevé equation obtained by translations along next-nearest-neighbor vectors. This equation is a generic (8-parameter) version of a 2-parameter elliptic difference equation found by reduction from Adler’s partial difference equation, the so-called Q4 equation. We also provide a projective reduction of the well known equation of Sakai.

  12. Development and implementation of the Good Neighbor Agreement (GNA) practice in the USA sustainable mining development.

    Science.gov (United States)

    Masaitis, Alexandra

    2014-05-01

    New economic, environmental and social challenges for the mining industry in the USA show the need to implement "responsible" mining practices that include improved community involvement. Conflicts which occur in the US territory and with US mining companies around the world are now common between the mining proponents, NGO's and communities. These conflicts can sometimes be alleviated by early development of modes of communication, and a formal discussion format that allows airing of concerns and potential resolution of problems. One of the methods that can formalize this process is to establish a Good Neighbor Agreement (GNA), which deals specifically with challenges in relationships between mining operations and the local communities. It is a new practice related to mining operations that are oriented toward social needs and concerns of local communities that arise during the normal life of a mine, which can achieve sustainable mining practices. The GNA project being currently developed at the University of Nevada, USA in cooperation with the Newmont Mining Corporation has a goal of creating an open company/community dialog that will help identify and address sociological and environmental concerns associated with mining. Discussion: The Good Neighbor Agreement currently evolving will address the following: 1. Identify spheres of possible cooperation between mining companies, government organizations, and NGO's. 2. Provide an economically viable mechanism for developing a partnership between mining operations and the local communities that will increase mining industry's accountability and provide higher levels of confidence for the community that a mine is operated in a safe and sustainable manner. Implementation of the GNA can help identify and evaluate conflict criteria in mining/community relationships; determine the status of concerns; determine the role and responsibilities of stakeholders; analyze problem resolution feasibility; maintain the community

  13. Neighborhood environments and its influence on physical activity in Olomouc and neighboring villages

    Directory of Open Access Journals (Sweden)

    Michal Kohout

    2014-03-01

    Full Text Available BACKGROUND: Modern society with development of new technologies greatly facilitates the activities of daily life and thus substantially eliminates human motion. This fact, together with a sedentary behavior is associated with considerable health risks, such as obesity, diabetes mellitus (type II, hypertension etc. A large part of the population is not aware of the negative consequences of physical inactivity, which may cause serious health problems. And this circumstance should be the main motivational factor to change lifestyle, including the environment. AIM: This study examines differences in the structure of physical activity in adults in Olomouc and neighboring villages within 15 km distance around Olomouc. The main objective was to determine how neighborhood environments affect physical activity of selected population groups. METHODS: All respondents were visited in person by authors and asked to participate in a research study using a Czech version of the questionnaire ANEWS. Data collection was carried out in May and June 2012 and data were obtained from 43 respondents aged 24-61 living in Olomouc and neighboring. RESULTS: The results showed that residents of urban areas are more physically active than nonurban residents. In the active area residents with higher walkability were associated with higher physical activity in urban residents, while the rural residents indicated higher physical activity in lower walkability areas. We found a significant difference in energy expenditure among respondents living in areas with higher and lower walkability in favor of the more walkable areas [H (1, 43 = 26.184, p ≤ .000]. CONCLUSIONS: Highest levels of physical activity represent men living in single-family houses and women living in multiple family houses. Participating respondents most frequently engaged in moderate physical activities. They spent more time sitting during work than sitting outside the workplace. Most frequently used

  14. Dominican and Haitian Neighbors: Making Moral Attitudes and Working Relationships in the Banana Bateyes

    Directory of Open Access Journals (Sweden)

    Kimberly Wynne

    2016-04-01

    insecurity by cultivating a perceived moral superiority over their Haitian neighbors. Ultimately, this article suggests that the practices of Dominicans struggling to earn a living alongside their Haitian neighbors reveals a relationship that is complicated by not only an anti-Haitian ideology, but by a historically constituted precarious life marginalizing 'batey 'residents together.

  15. Modifiers of Neighbors' Bystander Intervention in Intimate Partner Violence: A Concept Mapping Study.

    Science.gov (United States)

    Wee, Sara; Todd, Mary-Justine; Oshiro, Michael; Greene, Emily; Frye, Victoria

    2016-03-01

    Encouraging bystander intervention in intimate partner violence (IPV) against women is potentially an important method of reducing the prevalence of such violence in urban communities. Most existing research has been conducted on campuses and in relation to sexual violence among teens or young adults. Our understanding of which bystander behaviors are feasible is nascent, and our knowledge of which situational factors influence neighbors' self-reported willingness to intervene is underdeveloped. We conducted a concept mapping study to identify potential bystander intervention behaviors in IPV among neighbors in urban settings; we also assessed whether perceived feasibility and effectiveness of those behaviors varied by situational characteristics. Using data collected from 41 residents of a low-income New York City neighborhood in late 2011, concept mapping was used to create a conceptual map of the 74 behaviors identified by participants. We examined participant differences in mean feasibility (i.e., that the participants "could" or "would" enact a behavior), feasibility given two situational characteristics (if the couple was perceived to have a history of IPV, and if children were believed to be involved or present), and perceived effectiveness of bystander behaviors. Differences across select sociodemographic factors of participants were also analyzed. A 13-cluster solution emerged, with clusters of bystander behaviors grouped into four larger cluster areas: victim focused, parenting/education focused, perpetrator focused, and community involvement focused. Bivariate analyses revealed that participants rated the four cluster areas as more feasible when a child was believed to be involved. Male participants rated intervention as less feasible when the couple was believed to have a history of IPV. Participants who reported a history of IPV victimization rated all four cluster areas as less effective on average, as compared with participants without a history of

  16. Intermediate Bandgap Solar Cells From Nanostructured Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Black, Marcie [Bandgap Engineering, Lincoln, MA (United States)

    2014-10-30

    This project aimed to demonstrate increased electronic coupling in silicon nanostructures relative to bulk silicon for the purpose of making high efficiency intermediate bandgap solar cells using silicon. To this end, we formed nanowires with controlled crystallographic orientation, small diameter, <111> sidewall faceting, and passivated surfaces to modify the electronic band structure in silicon by breaking down the symmetry of the crystal lattice. We grew and tested these silicon nanowires with <110>-growth axes, which is an orientation that should produce the coupling enhancement.

  17. Diamond deposition on siliconized stainless steel

    International Nuclear Information System (INIS)

    Alvarez, F.; Reinoso, M.; Huck, H.; Rosenbusch, M.

    2010-01-01

    Silicon diffusion layers in AISI 304 and AISI 316 type stainless steels were investigated as an alternative to surface barrier coatings for diamond film growth. Uniform 2 μm thick silicon rich interlayers were obtained by coating the surface of the steels with silicon and performing diffusion treatments at 800 deg. C. Adherent diamond films with low sp 2 carbon content were deposited on the diffused silicon layers by a modified hot filament assisted chemical vapor deposition (HFCVD) method. Characterization of as-siliconized layers and diamond coatings was performed by energy dispersive X-ray analysis, scanning electron microscopy, X-ray diffraction and Raman spectroscopy.

  18. Method For Producing Mechanically Flexible Silicon Substrate

    KAUST Repository

    Hussain, Muhammad Mustafa

    2014-08-28

    A method for making a mechanically flexible silicon substrate is disclosed. In one embodiment, the method includes providing a silicon substrate. The method further includes forming a first etch stop layer in the silicon substrate and forming a second etch stop layer in the silicon substrate. The method also includes forming one or more trenches over the first etch stop layer and the second etch stop layer. The method further includes removing the silicon substrate between the first etch stop layer and the second etch stop layer.

  19. Transmutation doping of silicon solar cells

    Science.gov (United States)

    Wood, R. F.; Westbrook, R. D.; Young, R. T.; Cleland, J. W.

    1977-01-01

    Normal isotopic silicon contains 3.05% of Si-30 which transmutes to P-31 after thermal neutron absorption, with a half-life of 2.6 hours. This reaction is used to introduce extremely uniform concentrations of phosphorus into silicon, thus eliminating the areal and spatial inhomogeneities characteristic of chemical doping. Annealing of the lattice damage in the irradiated silicon does not alter the uniformity of dopant distribution. Transmutation doping also makes it possible to introduce phosphorus into polycrystalline silicon without segregation of the dopant at the grain boundaries. The use of neutron transmutation doped (NTD) silicon in solar cell research and development is discussed.

  20. Hybrid Integrated Platforms for Silicon Photonics

    Science.gov (United States)

    Liang, Di; Roelkens, Gunther; Baets, Roel; Bowers, John E.

    2010-01-01

    A review of recent progress in hybrid integrated platforms for silicon photonics is presented. Integration of III-V semiconductors onto silicon-on-insulator substrates based on two different bonding techniques is compared, one comprising only inorganic materials, the other technique using an organic bonding agent. Issues such as bonding process and mechanism, bonding strength, uniformity, wafer surface requirement, and stress distribution are studied in detail. The application in silicon photonics to realize high-performance active and passive photonic devices on low-cost silicon wafers is discussed. Hybrid integration is believed to be a promising technology in a variety of applications of silicon photonics.

  1. Method For Producing Mechanically Flexible Silicon Substrate

    KAUST Repository

    Hussain, Muhammad Mustafa; Rojas, Jhonathan Prieto

    2014-01-01

    A method for making a mechanically flexible silicon substrate is disclosed. In one embodiment, the method includes providing a silicon substrate. The method further includes forming a first etch stop layer in the silicon substrate and forming a second etch stop layer in the silicon substrate. The method also includes forming one or more trenches over the first etch stop layer and the second etch stop layer. The method further includes removing the silicon substrate between the first etch stop layer and the second etch stop layer.

  2. Silicon on insulator self-aligned transistors

    Science.gov (United States)

    McCarthy, Anthony M.

    2003-11-18

    A method for fabricating thin-film single-crystal silicon-on-insulator (SOI) self-aligned transistors. Standard processing of silicon substrates is used to fabricate the transistors. Physical spaces, between the source and gate, and the drain and gate, introduced by etching the polysilicon gate material, are used to provide connecting implants (bridges) which allow the transistor to perform normally. After completion of the silicon substrate processing, the silicon wafer is bonded to an insulator (glass) substrate, and the silicon substrate is removed leaving the transistors on the insulator (glass) substrate. Transistors fabricated by this method may be utilized, for example, in flat panel displays, etc.

  3. Hybrid Integrated Platforms for Silicon Photonics

    Directory of Open Access Journals (Sweden)

    John E. Bowers

    2010-03-01

    Full Text Available A review of recent progress in hybrid integrated platforms for silicon photonics is presented. Integration of III-V semiconductors onto silicon-on-insulator substrates based on two different bonding techniques is compared, one comprising only inorganic materials, the other technique using an organic bonding agent. Issues such as bonding process and mechanism, bonding strength, uniformity, wafer surface requirement, and stress distribution are studied in detail. The application in silicon photonics to realize high-performance active and passive photonic devices on low-cost silicon wafers is discussed. Hybrid integration is believed to be a promising technology in a variety of applications of silicon photonics.

  4. Dispersion toughened silicon carbon ceramics

    Science.gov (United States)

    Wei, G.C.

    1984-01-01

    Fracture resistant silicon carbide ceramics are provided by incorporating therein a particulate dispersoid selected from the group consisting of (a) a mixture of boron, carbon and tungsten, (b) a mixture of boron, carbon and molybdenum, (c) a mixture of boron, carbon and titanium carbide, (d) a mixture of aluminum oxide and zirconium oxide, and (e) boron nitride. 4 figures.

  5. Reaction-bonded silicon nitride

    International Nuclear Information System (INIS)

    Porz, F.

    1982-10-01

    Reaction-bonded silicon nitride (RBSN) has been characterized. The oxidation behaviour in air up to 1500 0 C and 3000 h and the effects of static and cyclic oxidation on room-temperature strength have been studied. (orig./IHOE) [de

  6. The ARGUS silicon vertex detector

    International Nuclear Information System (INIS)

    Michel, E.; Ball, S.; Ehret, K.; Geyer, C.; Hesselbarth, J.; Hoelscher, A.; Hofmann, W.; Holzer, B.; Huepper, A.; Khan, S.; Knoepfle, K.T.; Seeger, M.; Spengler, J.; Brogle, M.; Horisberger, R.

    1994-01-01

    A silicon microstrip vertex detector has been built as an upgrade to the ARGUS detector for increased precision and efficiency in the reconstruction of decay vertices. This paper discusses the mechanical and electronic design of this device and presents first results from its successful test operation yielding an impact parameter resolution of about 18 μm. ((orig.))

  7. Impurities of oxygen in silicon

    International Nuclear Information System (INIS)

    Gomes, V.M.S.

    1985-01-01

    The electronic structure of oxygen complex defects in silicon, using molecular cluster model with saturation by watson sphere into the formalism of Xα multiple scattering method is studied. A systematic study of the simulation of perfect silicon crystal and an analysis of the increasing of atom number in the clusters are done to choose the suitable cluster for the calculations. The divacancy in three charge states (Si:V 2 + , Si:V 2 0 , Si:V 2 - ), of the oxygen pair (Si:O 2 ) and the oxygen-vacancy pair (Si:O.V) neighbours in the silicon lattice, is studied. Distortions for the symmetry were included in the Si:V 2 + and Si:O 2 systems. The behavior of defect levels related to the cluster size of Si:V 2 0 and Si:O 2 systems, the insulated oxygen impurity of silicon in interstitial position (Si:O i ), and the complexes involving four oxygen atoms are analysed. (M.C.K.) [pt

  8. Seedless electroplating on patterned silicon

    NARCIS (Netherlands)

    Vargas Llona, Laura Dolores; Jansen, Henricus V.; Elwenspoek, Michael Curt

    2006-01-01

    Nickel thin films have been electrodeposited without the use of an additional seed layer, on highly doped silicon wafers. These substrates conduct sufficiently well to allow deposition using a peripherical electrical contact on the wafer. Films 2 μm thick have been deposited using a nickel sulfamate

  9. Aleph silicon microstrip vertex detector

    CERN Multimedia

    Laurent Guiraud

    1998-01-01

    This microstrip vertex locator was located at the heart of the ALEPH experiment, one of the four experiments at the Large Electron-Positron (LEP) collider. In the experiments at CERN's LEP, which ran from 1989 to 2000, modern silicon microvertex detectors, such as those used at ALEPH, monitored the production of short-lived particles close to the beam pipe.

  10. Silicon nanowire hot carrier electroluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Plessis, M. du, E-mail: monuko@up.ac.za; Joubert, T.-H.

    2016-08-31

    Avalanche electroluminescence from silicon pn junctions has been known for many years. However, the internal quantum efficiencies of these devices are quite low due to the indirect band gap nature of the semiconductor material. In this study we have used reach-through biasing and SOI (silicon-on-insulator) thin film structures to improve the internal power efficiency and the external light extraction efficiency. Both continuous silicon thin film pn junctions and parallel nanowire pn junctions were manufactured using a custom SOI technology. The pn junctions are operated in the reach-through mode of operation, thus increasing the average electric field within the fully depleted region. Experimental results of the emission spectrum indicate that the most dominant photon generating mechanism is due to intraband hot carrier relaxation processes. It was found that the SOI nanowire light source external power efficiency is at least an order of magnitude better than the comparable bulk CMOS (Complementary Metal Oxide Semiconductor) light source. - Highlights: • We investigate effect of electric field on silicon avalanche electroluminescence. • With reach-through pn junctions the current and carrier densities are kept constant. • Higher electric fields increase short wavelength radiation. • Higher electric fields decrease long wavelength radiation. • The effect of the electric field indicates intraband transitions as main mechanism.

  11. Silicon quantum dots: surface matters

    Czech Academy of Sciences Publication Activity Database

    Dohnalová, K.; Gregorkiewicz, T.; Kůsová, Kateřina

    2014-01-01

    Roč. 26, č. 17 (2014), 1-28 ISSN 0953-8984 R&D Projects: GA ČR GPP204/12/P235 Institutional support: RVO:68378271 Keywords : silicon quantum dots * quantum dot * surface chemistry * quantum confinement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.346, year: 2014

  12. prismane structure by silicon substitution

    Indian Academy of Sciences (India)

    Using the second-order Møller–Plesset perturbation (MP2) theoretic method and the cc-pVDZ basis set, it is shown that with an increase in the number of carbon atoms substituted by silicon, the [6]-prismane structure becomes increasingly more stable, relative to the two isolated benzene (like) structures. A similar trend is ...

  13. Thermal carbonization of nanoporous silicon

    Indian Academy of Sciences (India)

    An interesting phenomenon is observed while carrying out thermal carbonization of porous silicon (PS) with an aim to arrest the natural surface degradation, and it is a burning issue for PS-based device applications. A tubular carbon structure has been observed on the PS surface. Raman, Fourier transform infrared ...

  14. The CDF Silicon Vertex Detector

    International Nuclear Information System (INIS)

    Tkaczyk, S.; Carter, H.; Flaugher, B.

    1993-01-01

    A silicon strip vertex detector was designed, constructed and commissioned at the CDF experiment at the Tevatron collider at Fermilab. The mechanical design of the detector, its cooling and monitoring are presented. The front end electronics employing a custom VLSI chip, the readout electronics and various components of the SVX system are described. The system performance and the experience with the operation of the

  15. The CDF Silicon Vertex Trigger

    International Nuclear Information System (INIS)

    Dell'Orso, Mauro

    2006-01-01

    Motivations, design, performance and ongoing upgrade of the CDF Silicon Vertex Trigger are presented. The system provides CDF with a powerful tool for online tracking with offline quality in order to enhance the reach on B-physics and large P t -physics coupled to b quarks

  16. Microelectromechanical pump utilizing porous silicon

    Science.gov (United States)

    Lantz, Jeffrey W [Albuquerque, NM; Stalford, Harold L [Norman, OK

    2011-07-19

    A microelectromechanical (MEM) pump is disclosed which includes a porous silicon region sandwiched between an inlet chamber and an outlet chamber. The porous silicon region is formed in a silicon substrate and contains a number of pores extending between the inlet and outlet chambers, with each pore having a cross-section dimension about equal to or smaller than a mean free path of a gas being pumped. A thermal gradient is provided along the length of each pore by a heat source which can be an electrical resistance heater or an integrated circuit (IC). A channel can be formed through the silicon substrate so that inlet and outlet ports can be formed on the same side of the substrate, or so that multiple MEM pumps can be connected in series to form a multi-stage MEM pump. The MEM pump has applications for use in gas-phase MEM chemical analysis systems, and can also be used for passive cooling of ICs.

  17. Untreated silicone breast implant rupture

    DEFF Research Database (Denmark)

    Hölmich, Lisbet R; Vejborg, Ilse M; Conrad, Carsten

    2004-01-01

    Implant rupture is a well-known complication of breast implant surgery that can pass unnoticed by both patient and physician. To date, no prospective study has addressed the possible health implications of silicone breast implant rupture. The aim of the present study was to evaluate whether untre...

  18. Influence of polycrystalline silicon layer on flow through «metal — p-Si» contact

    Directory of Open Access Journals (Sweden)

    Smyntyna V. A.

    2011-11-01

    Full Text Available Based on the results of investigations of charge transport in the "metal — p-Si" contacts with different thickness of polycrystalline p-Si layer the mechanisms of charge transport through such structures are shown. It is established that with increasing thickness of the layer of polycrystalline p-Si current transport mechanism changes from a double injection into the drift-diffusion. This change is due to an increase in the drift current component in the space charge zone of "metal — p-Si" contact, which arises as a result of increased surface density of scattering barriers, which are localized at the boundaries of neighboring silicon polycrystals.

  19. Flexible Thermoelectric Generators on Silicon Fabric

    KAUST Repository

    Sevilla, Galo T.

    2012-11-01

    In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart textile, wearable electronics and many other exciting applications. However, low thermal budget processing and fundamentally limited electron mobility hinders its potential to be competitive with well established and highly developed silicon technology. The use of silicon in flexible electronics involve expensive and abrasive materials and processes. In this work, high performance flexible thermoelectric energy harvesters are demonstrated from low cost bulk silicon (100) wafers. The fabrication of the micro- harvesters was done using existing silicon processes on silicon (100) and then peeled them off from the original substrate leaving it for reuse. Peeled off silicon has 3.6% thickness of bulk silicon reducing the thermal loss significantly and generating nearly 30% more output power than unpeeled harvesters. The demonstrated generic batch processing shows a pragmatic way of peeling off a whole silicon circuitry after conventional fabrication on bulk silicon wafers for extremely deformable high performance integrated electronics. In summary, by using a novel, low cost process, this work has successfully integrated existing and highly developed fabrication techniques to introduce a flexible energy harvester for sustainable applications.

  20. Silicon photonics: some remaining challenges

    Science.gov (United States)

    Reed, G. T.; Topley, R.; Khokhar, A. Z.; Thompson, D. J.; Stanković, S.; Reynolds, S.; Chen, X.; Soper, N.; Mitchell, C. J.; Hu, Y.; Shen, L.; Martinez-Jimenez, G.; Healy, N.; Mailis, S.; Peacock, A. C.; Nedeljkovic, M.; Gardes, F. Y.; Soler Penades, J.; Alonso-Ramos, C.; Ortega-Monux, A.; Wanguemert-Perez, G.; Molina-Fernandez, I.; Cheben, P.; Mashanovich, G. Z.

    2016-03-01

    This paper discusses some of the remaining challenges for silicon photonics, and how we at Southampton University have approached some of them. Despite phenomenal advances in the field of Silicon Photonics, there are a number of areas that still require development. For short to medium reach applications, there is a need to improve the power consumption of photonic circuits such that inter-chip, and perhaps intra-chip applications are viable. This means that yet smaller devices are required as well as thermally stable devices, and multiple wavelength channels. In turn this demands smaller, more efficient modulators, athermal circuits, and improved wavelength division multiplexers. The debate continues as to whether on-chip lasers are necessary for all applications, but an efficient low cost laser would benefit many applications. Multi-layer photonics offers the possibility of increasing the complexity and effectiveness of a given area of chip real estate, but it is a demanding challenge. Low cost packaging (in particular, passive alignment of fibre to waveguide), and effective wafer scale testing strategies, are also essential for mass market applications. Whilst solutions to these challenges would enhance most applications, a derivative technology is emerging, that of Mid Infra-Red (MIR) silicon photonics. This field will build on existing developments, but will require key enhancements to facilitate functionality at longer wavelengths. In common with mainstream silicon photonics, significant developments have been made, but there is still much left to do. Here we summarise some of our recent work towards wafer scale testing, passive alignment, multiplexing, and MIR silicon photonics technology.

  1. Air Pollution from Livestock Farms Is Associated with Airway Obstruction in Neighboring Residents.

    Science.gov (United States)

    Borlée, Floor; Yzermans, C Joris; Aalders, Bernadette; Rooijackers, Jos; Krop, Esmeralda; Maassen, Catharina B M; Schellevis, François; Brunekreef, Bert; Heederik, Dick; Smit, Lidwien A M

    2017-11-01

    Livestock farm emissions may not only affect respiratory health of farmers but also of neighboring residents. To explore associations between spatial and temporal variation in pollutant emissions from livestock farms and lung function in a general, nonfarming, rural population in the Netherlands. We conducted a cross-sectional study in 2,308 adults (age, 20-72 yr). A pulmonary function test was performed measuring prebronchodilator and post-bronchodilator FEV 1 , FVC, FEV 1 /FVC, and maximum mid-expiratory flow (MMEF). Spatial exposure was assessed as (1) number of farms within 500 m and 1,000 m of the home, (2) distance to the nearest farm, and (3) modeled annual average fine dust emissions from farms within 500 m and 1,000 m of the home address. Temporal exposure was assessed as week-average ambient particulate matter livestock farms within a 1,000-m buffer from the home address and MMEF, which was more pronounced in participants without atopy. No associations were found with other spatial exposure variables. Week-average particulate matter livestock air pollution emissions are associated with lung function deficits in nonfarming residents.

  2. Local Order in the Unfolded State: Conformational Biases and Nearest Neighbor Interactions

    Directory of Open Access Journals (Sweden)

    Siobhan Toal

    2014-07-01

    Full Text Available The discovery of Intrinsically Disordered Proteins, which contain significant levels of disorder yet perform complex biologically functions, as well as unwanted aggregation, has motivated numerous experimental and theoretical studies aimed at describing residue-level conformational ensembles. Multiple lines of evidence gathered over the last 15 years strongly suggest that amino acids residues display unique and restricted conformational preferences in the unfolded state of peptides and proteins, contrary to one of the basic assumptions of the canonical random coil model. To fully understand residue level order/disorder, however, one has to gain a quantitative, experimentally based picture of conformational distributions and to determine the physical basis underlying residue-level conformational biases. Here, we review the experimental, computational and bioinformatic evidence for conformational preferences of amino acid residues in (mostly short peptides that can be utilized as suitable model systems for unfolded states of peptides and proteins. In this context particular attention is paid to the alleged high polyproline II preference of alanine. We discuss how these conformational propensities may be modulated by peptide solvent interactions and so called nearest-neighbor interactions. The relevance of conformational propensities for the protein folding problem and the understanding of IDPs is briefly discussed.

  3. Disordering scaling and generalized nearest-neighbor approach in the thermodynamics of Lennard-Jones systems

    International Nuclear Information System (INIS)

    Vorob'ev, V.S.

    2003-01-01

    We suggest a concept of multiple disordering scaling of the crystalline state. Such a scaling procedure applied to a crystal leads to the liquid and (in low density limit) gas states. This approach provides an explanation to a high value of configuration (common) entropy of liquefied noble gases, which can be deduced from experimental data. We use the generalized nearest-neighbor approach to calculate free energy and pressure of the Lennard-Jones systems after performing this scaling procedure. These thermodynamic functions depend on one parameter characterizing the disordering only. Condensed states of the system (liquid and solid) correspond to small values of this parameter. When this parameter tends to unity, we get an asymptotically exact equation of state for a gas involving the second virial coefficient. A reasonable choice of the values for the disordering parameter (ranging between zero and unity) allows us to find the lines of coexistence between different phase states in the Lennard-Jones systems, which are in a good agreement with the available experimental data

  4. With the help of one's neighbors: externalities in the production of nutrition in Peru.

    Science.gov (United States)

    Alderman, Harold; Hentschel, Jesko; Sabates, Ricardo

    2003-05-01

    Both public and private resources contribute to the nutritional status of children. In addition, the investments made by one household may contribute to the health of other households in the neighborhood through improvements in the sanitation environment and through increases in shared knowledge. This paper measures the externalities of investments in nutrition by indicating the impact of the education of women in Peruvian neighborhoods on the nutrition of children in other households, after controlling for the education and income of those households. We find that in rural areas this shared knowledge has a significant impact on nutrition, with the coefficient of an increase in the average education of women in the neighborhood being appreciable larger than the coefficient of education in isolation. In addition, we indicate the impact of the water and sanitation environment in the neighborhood, again controlling for the household's own access to sanitation and water. In both urban and rural areas, we observe externalities from investments in such household level infrastructure with the evidence particularly strong for sanitation made by neighboring households.

  5. Building a Co-Created Citizen Science Program with Community Members Neighboring a Hazardous Waste Site

    Science.gov (United States)

    Ramirez-Andreotta, M.; Brusseau, M. L. L.; Artiola, J. F.; Maier, R. M.; Gandolfi, A. J.

    2015-12-01

    A research project that is only expert-driven may ignore the role of local knowledge in research, often gives low priority to the development of a comprehensive strategy to engage the community, and may not deliver the results of the study to the community in an effective way. To date, only a limited number of co-created citizen science projects, where community members are involved in most or all steps of the scientific process, have been initiated at contaminated sites and even less in conjunction with risk communication. Gardenroots: The Dewey-Humboldt AZ Garden Project was a place-based, co-created citizen science project where community members and researchers together: defined the question for study, developed hypotheses, collected environmental samples, disseminated results broadly, translated the results into action, and posed new research questions. This co-created environmental research project produced new data and addressed an additional exposure route (consumption of vegetables grown in soils with elevated arsenic levels) that was not being evaluated in the current site assessment. Furthermore, co-producing science led to both individual learning and social-ecological outcomes. This approach illustrates the benefits of a co-created citizen-science program in addressing the complex problems that arise in communities neighboring a hazardous waste sites. Such a project increased the community's involvement in regional environmental assessment and decision-making, which has the potential to help mitigate environmental exposures and thereby reduce associated risks.

  6. Fracton topological order from nearest-neighbor two-spin interactions and dualities

    Science.gov (United States)

    Slagle, Kevin; Kim, Yong Baek

    2017-10-01

    Fracton topological order describes a remarkable phase of matter, which can be characterized by fracton excitations with constrained dynamics and a ground-state degeneracy that increases exponentially with the length of the system on a three-dimensional torus. However, previous models exhibiting this order require many-spin interactions, which may be very difficult to realize in a real material or cold atom system. In this work, we present a more physically realistic model which has the so-called X-cube fracton topological order [Vijay, Haah, and Fu, Phys. Rev. B 94, 235157 (2016), 10.1103/PhysRevB.94.235157] but only requires nearest-neighbor two-spin interactions. The model lives on a three-dimensional honeycomb-based lattice with one to two spin-1/2 degrees of freedom on each site and a unit cell of six sites. The model is constructed from two orthogonal stacks of Z2 topologically ordered Kitaev honeycomb layers [Kitaev, Ann. Phys. 321, 2 (2006), 10.1016/j.aop.2005.10.005], which are coupled together by a two-spin interaction. It is also shown that a four-spin interaction can be included to instead stabilize 3+1D Z2 topological order. We also find dual descriptions of four quantum phase transitions in our model, all of which appear to be discontinuous first-order transitions.

  7. COMPARATIVE ANALYSIS OF THE GORJ COUNTY OF SOCIO-ECONOMIC WITH NEIGHBORING COUNTIES IN CRISIS

    Directory of Open Access Journals (Sweden)

    CONSTANTA ENEA

    2012-05-01

    Full Text Available Purpose of the paper is to highlight how the economy evolved in the Florida county comparison with neighboring counties in economic crisis that society through the difficult years. also study and make acomparison in terms of demographic characteristics, respectively, compared between young and old, labor migration, etc. form., indices that are decisive for evaluating the economic situation of the county above mentioned. Economically, the county is in the connection between the economy and sub-mountainous and mountainous plains. The specificity of its resources, Gorj is a leading energy suppliers of the country, both as primary energy (coal, oil and processed (heat and electricity1. Results and statistical sources that Gorj currently produces more than 20% of the thermoelectric power of2. In terms of population below national averages Gorj is the fourth in the region after Olt and Valcea. Is medium in size, being the third after Dolj and Valcea. In terms of urbanization, Gorj is below the national average and third in the region after Dolj and Mehedinti. After the general level of development, the county is in a less favorable position, because the permanent part is characterized by a lower level of development.

  8. Effect of Growing Size of Interaction Neighbors on the Evolution of Cooperation in Spatial Snowdrift Game

    International Nuclear Information System (INIS)

    Zhang Juanjuan; Sun Shiwen; Wang Li; Xia Chengyi; Wang Juan; Wang Zhen

    2012-01-01

    In this paper, we study the influence of the size of interaction neighbors (k) on the evolution of cooperation in the spatial snowdrift game. At first, we consider the effects of noise K and cost-to-benefit ratio r, the simulation results indicate that the evolution of cooperation depends on the combined action of noise and cost-to-benefit ratio. For a lower r, the cooperators are multitudinous and the cooperation frequency ultimately increases to 1 as the increase of noise. However, for a higher r, the defectors account for the majority of the game and dominate the game if the noise is large enough. Then we mainly investigate how k influences the evolution of cooperation by varying the noise in detail. We find that the frequency of cooperators is closely related to the size of neighborhood and cost-to-benefit ratio r. In the case of lower r, the augmentation of k plays no positive role in promoting the cooperation as compared with that of k = 4, while for higher r the cooperation is improved for a growing size of neighborhood. At last, based on the above discussions, we explore the cluster-forming mechanism among the cooperators. The current results are beneficial to further understand the evolution of cooperation in many natural, social and biological systems. (general)

  9. Neighboring block based disparity vector derivation for multiview compatible 3D-AVC

    Science.gov (United States)

    Kang, Jewon; Chen, Ying; Zhang, Li; Zhao, Xin; Karczewicz, Marta

    2013-09-01

    3D-AVC being developed under Joint Collaborative Team on 3D Video Coding (JCT-3V) significantly outperforms the Multiview Video Coding plus Depth (MVC+D) which simultaneously encodes texture views and depth views with the multiview extension of H.264/AVC (MVC). However, when the 3D-AVC is configured to support multiview compatibility in which texture views are decoded without depth information, the coding performance becomes significantly degraded. The reason is that advanced coding tools incorporated into the 3D-AVC do not perform well due to the lack of a disparity vector converted from the depth information. In this paper, we propose a disparity vector derivation method utilizing only the information of texture views. Motion information of neighboring blocks is used to determine a disparity vector for a macroblock, so that the derived disparity vector is efficiently used for the coding tools in 3D-AVC. The proposed method significantly improves a coding gain of the 3D-AVC in the multiview compatible mode about 20% BD-rate saving in the coded views and 26% BD-rate saving in the synthesized views on average.

  10. Adaptive neighbor connection for PRMs: A natural fit for heterogeneous environments and parallelism

    KAUST Repository

    Ekenna, Chinwe; Jacobs, Sam Ade; Thomas, Shawna; Amato, Nancy M.

    2013-01-01

    Probabilistic Roadmap Methods (PRMs) are widely used motion planning methods that sample robot configurations (nodes) and connect them to form a graph (roadmap) containing feasible trajectories. Many PRM variants propose different strategies for each of the steps and choosing among them is problem dependent. Planning in heterogeneous environments and/or on parallel machines necessitates dividing the problem into regions where these choices have to be made for each one. Hand-selecting the best method for each region becomes infeasible. In particular, there are many ways to select connection candidates, and choosing the appropriate strategy is input dependent. In this paper, we present a general connection framework that adaptively selects a neighbor finding strategy from a candidate set of options. Our framework learns which strategy to use by examining their success rates and costs. It frees the user of the burden of selecting the best strategy and allows the selection to change over time. We perform experiments on rigid bodies of varying geometry and articulated linkages up to 37 degrees of freedom. Our results show that strategy performance is indeed problem/region dependent, and our adaptive method harnesses their strengths. Over all problems studied, our method differs the least from manual selection of the best method, and if one were to manually select a single method across all problems, the performance can be quite poor. Our method is able to adapt to changing sampling density and learns different strategies for each region when the problem is partitioned for parallelism. © 2013 IEEE.

  11. Adaptive neighbor connection for PRMs: A natural fit for heterogeneous environments and parallelism

    KAUST Repository

    Ekenna, Chinwe

    2013-11-01

    Probabilistic Roadmap Methods (PRMs) are widely used motion planning methods that sample robot configurations (nodes) and connect them to form a graph (roadmap) containing feasible trajectories. Many PRM variants propose different strategies for each of the steps and choosing among them is problem dependent. Planning in heterogeneous environments and/or on parallel machines necessitates dividing the problem into regions where these choices have to be made for each one. Hand-selecting the best method for each region becomes infeasible. In particular, there are many ways to select connection candidates, and choosing the appropriate strategy is input dependent. In this paper, we present a general connection framework that adaptively selects a neighbor finding strategy from a candidate set of options. Our framework learns which strategy to use by examining their success rates and costs. It frees the user of the burden of selecting the best strategy and allows the selection to change over time. We perform experiments on rigid bodies of varying geometry and articulated linkages up to 37 degrees of freedom. Our results show that strategy performance is indeed problem/region dependent, and our adaptive method harnesses their strengths. Over all problems studied, our method differs the least from manual selection of the best method, and if one were to manually select a single method across all problems, the performance can be quite poor. Our method is able to adapt to changing sampling density and learns different strategies for each region when the problem is partitioned for parallelism. © 2013 IEEE.

  12. Rapid corn and soybean mapping in US Corn Belt and neighboring areas

    Science.gov (United States)

    Zhong, Liheng; Yu, Le; Li, Xuecao; Hu, Lina; Gong, Peng

    2016-11-01

    The goal of this study was to promptly map the extent of corn and soybeans early in the growing season. A classification experiment was conducted for the US Corn Belt and neighboring states, which is the most important production area of corn and soybeans in the world. To improve the timeliness of the classification algorithm, training was completely based on reference data and images from other years, circumventing the need to finish reference data collection in the current season. To account for interannual variability in crop development in the cross-year classification scenario, several innovative strategies were used. A random forest classifier was used in all tests, and MODIS surface reflectance products from the years 2008-2014 were used for training and cross-year validation. It is concluded that the fuzzy classification approach is necessary to achieve satisfactory results with R-squared ~0.9 (compared with the USDA Cropland Data Layer). The year of training data is an important factor, and it is recommended to select a year with similar crop phenology as the mapping year. With this phenology-based and cross-year-training method, in 2015 we mapped the cropping proportion of corn and soybeans around mid-August, when the two crops just reached peak growth.

  13. Warming and neighbor removal affect white spruce seedling growth differently above and below treeline.

    Science.gov (United States)

    Okano, Kyoko; Bret-Harte, M Syndonia

    2015-01-01

    Climate change is expected to be pronounced towards higher latitudes and altitudes. Warming triggers treeline and vegetation shifts, which may aggravate interspecific competition and affect biodiversity. This research tested the effects of a warming climate, habitat type, and neighboring plant competition on the establishment and growth of white spruce (Picea glauca (Moench) Voss) seedlings in a subarctic mountain region. P. glauca seedlings were planted in June 2010 under 4 different treatments (high/control temperatures, with/without competition) in 3 habitats (alpine ridge above treeline/tundra near treeline /forest below treeline habitats). After two growing seasons in 2011, growth, photosynthesis and foliar C and N data were obtained from a total of 156, one-and-a-half year old seedlings that had survived. Elevated temperatures increased growth and photosynthetic rates above and near treeline, but decreased them below treeline. Competition was increased by elevated temperatures in all habitat types. Our results suggest that increasing temperatures will have positive effects on the growth of P. glauca seedlings at the locations where P. glauca is expected to expand its habitat, but increasing temperatures may have negative effects on seedlings growing in mature forests. Due to interspecific competition, possibly belowground competition, the upslope expansion of treelines may not be as fast in the future as it was the last fifty years.

  14. Third nearest neighbor parameterized tight binding model for graphene nano-ribbons

    Directory of Open Access Journals (Sweden)

    Van-Truong Tran

    2017-07-01

    Full Text Available The existing tight binding models can very well reproduce the ab initio band structure of a 2D graphene sheet. For graphene nano-ribbons (GNRs, the current sets of tight binding parameters can successfully describe the semi-conducting behavior of all armchair GNRs. However, they are still failing in reproducing accurately the slope of the bands that is directly associated with the group velocity and the effective mass of electrons. In this work, both density functional theory and tight binding calculations were performed and a new set of tight binding parameters up to the third nearest neighbors including overlap terms is introduced. The results obtained with this model offer excellent agreement with the predictions of the density functional theory in most cases of ribbon structures, even in the high-energy region. Moreover, this set can induce electron-hole asymmetry as manifested in results from density functional theory. Relevant outcomes are also achieved for armchair ribbons of various widths as well as for zigzag structures, thus opening a route for multi-scale atomistic simulation of large systems that cannot be considered using density functional theory.

  15. Spatiotemporal distribution of Oklahoma earthquakes: Exploring relationships using a nearest-neighbor approach

    Science.gov (United States)

    Vasylkivska, Veronika S.; Huerta, Nicolas J.

    2017-07-01

    Determining the spatiotemporal characteristics of natural and induced seismic events holds the opportunity to gain new insights into why these events occur. Linking the seismicity characteristics with other geologic, geographic, natural, or anthropogenic factors could help to identify the causes and suggest mitigation strategies that reduce the risk associated with such events. The nearest-neighbor approach utilized in this work represents a practical first step toward identifying statistically correlated clusters of recorded earthquake events. Detailed study of the Oklahoma earthquake catalog's inherent errors, empirical model parameters, and model assumptions is presented. We found that the cluster analysis results are stable with respect to empirical parameters (e.g., fractal dimension) but were sensitive to epicenter location errors and seismicity rates. Most critically, we show that the patterns in the distribution of earthquake clusters in Oklahoma are primarily defined by spatial relationships between events. This observation is a stark contrast to California (also known for induced seismicity) where a comparable cluster distribution is defined by both spatial and temporal interactions between events. These results highlight the difficulty in understanding the mechanisms and behavior of induced seismicity but provide insights for future work.

  16. Particle Communication and Domain Neighbor Coupling: Scalable Domain Decomposed Algorithms for Monte Carlo Particle Transport

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, M. J.; Brantley, P. S.

    2015-01-20

    In order to run Monte Carlo particle transport calculations on new supercomputers with hundreds of thousands or millions of processors, care must be taken to implement scalable algorithms. This means that the algorithms must continue to perform well as the processor count increases. In this paper, we examine the scalability of:(1) globally resolving the particle locations on the correct processor, (2) deciding that particle streaming communication has finished, and (3) efficiently coupling neighbor domains together with different replication levels. We have run domain decomposed Monte Carlo particle transport on up to 221 = 2,097,152 MPI processes on the IBM BG/Q Sequoia supercomputer and observed scalable results that agree with our theoretical predictions. These calculations were carefully constructed to have the same amount of work on every processor, i.e. the calculation is already load balanced. We also examine load imbalanced calculations where each domain’s replication level is proportional to its particle workload. In this case we show how to efficiently couple together adjacent domains to maintain within workgroup load balance and minimize memory usage.

  17. Geometric k-nearest neighbor estimation of entropy and mutual information

    Science.gov (United States)

    Lord, Warren M.; Sun, Jie; Bollt, Erik M.

    2018-03-01

    Nonparametric estimation of mutual information is used in a wide range of scientific problems to quantify dependence between variables. The k-nearest neighbor (knn) methods are consistent, and therefore expected to work well for a large sample size. These methods use geometrically regular local volume elements. This practice allows maximum localization of the volume elements, but can also induce a bias due to a poor description of the local geometry of the underlying probability measure. We introduce a new class of knn estimators that we call geometric knn estimators (g-knn), which use more complex local volume elements to better model the local geometry of the probability measures. As an example of this class of estimators, we develop a g-knn estimator of entropy and mutual information based on elliptical volume elements, capturing the local stretching and compression common to a wide range of dynamical system attractors. A series of numerical examples in which the thickness of the underlying distribution and the sample sizes are varied suggest that local geometry is a source of problems for knn methods such as the Kraskov-Stögbauer-Grassberger estimator when local geometric effects cannot be removed by global preprocessing of the data. The g-knn method performs well despite the manipulation of the local geometry. In addition, the examples suggest that the g-knn estimators can be of particular relevance to applications in which the system is large, but the data size is limited.

  18. An RFID Indoor Positioning Algorithm Based on Bayesian Probability and K-Nearest Neighbor.

    Science.gov (United States)

    Xu, He; Ding, Ye; Li, Peng; Wang, Ruchuan; Li, Yizhu

    2017-08-05

    The Global Positioning System (GPS) is widely used in outdoor environmental positioning. However, GPS cannot support indoor positioning because there is no signal for positioning in an indoor environment. Nowadays, there are many situations which require indoor positioning, such as searching for a book in a library, looking for luggage in an airport, emergence navigation for fire alarms, robot location, etc. Many technologies, such as ultrasonic, sensors, Bluetooth, WiFi, magnetic field, Radio Frequency Identification (RFID), etc., are used to perform indoor positioning. Compared with other technologies, RFID used in indoor positioning is more cost and energy efficient. The Traditional RFID indoor positioning algorithm LANDMARC utilizes a Received Signal Strength (RSS) indicator to track objects. However, the RSS value is easily affected by environmental noise and other interference. In this paper, our purpose is to reduce the location fluctuation and error caused by multipath and environmental interference in LANDMARC. We propose a novel indoor positioning algorithm based on Bayesian probability and K -Nearest Neighbor (BKNN). The experimental results show that the Gaussian filter can filter some abnormal RSS values. The proposed BKNN algorithm has the smallest location error compared with the Gaussian-based algorithm, LANDMARC and an improved KNN algorithm. The average error in location estimation is about 15 cm using our method.

  19. An RFID Indoor Positioning Algorithm Based on Bayesian Probability and K-Nearest Neighbor

    Directory of Open Access Journals (Sweden)

    He Xu

    2017-08-01

    Full Text Available The Global Positioning System (GPS is widely used in outdoor environmental positioning. However, GPS cannot support indoor positioning because there is no signal for positioning in an indoor environment. Nowadays, there are many situations which require indoor positioning, such as searching for a book in a library, looking for luggage in an airport, emergence navigation for fire alarms, robot location, etc. Many technologies, such as ultrasonic, sensors, Bluetooth, WiFi, magnetic field, Radio Frequency Identification (RFID, etc., are used to perform indoor positioning. Compared with other technologies, RFID used in indoor positioning is more cost and energy efficient. The Traditional RFID indoor positioning algorithm LANDMARC utilizes a Received Signal Strength (RSS indicator to track objects. However, the RSS value is easily affected by environmental noise and other interference. In this paper, our purpose is to reduce the location fluctuation and error caused by multipath and environmental interference in LANDMARC. We propose a novel indoor positioning algorithm based on Bayesian probability and K-Nearest Neighbor (BKNN. The experimental results show that the Gaussian filter can filter some abnormal RSS values. The proposed BKNN algorithm has the smallest location error compared with the Gaussian-based algorithm, LANDMARC and an improved KNN algorithm. The average error in location estimation is about 15 cm using our method.

  20. Palinspastic reconstruction and geological evolution of Jurassic basins in Mongolia and neighboring China

    Directory of Open Access Journals (Sweden)

    Wu Genyao

    2013-07-01

    Full Text Available The important event in Jurassic tectonics in Mongolia was the subduction and closure of the Mongolia-Okhotsk ocean; correspondingly, basin evolution can be divided into two main stages, related to the orogeny and collapse of the orogenic belt, respectively. The developing of Early–Middle Jurassic basins to the north of the ocean resulted from back-arc extension. The fossil sutures, from the China–SE Asia sub-continent to the south of the ocean, were rejuvenated by subduction-related orogeny; in addition, the Yanshanian intra-continental movement occurred. Three Early–Middle Jurassic molasse basins were developed by movement in Inner Mongolia, all of which stretched westwards (or northwards into Mongolia; therefore, the molasse basins in eastern and southern Mongolia had the same geometric and kinematic features as the basins in the Inner Mongolia. Owing to the collapse of the Mongolia-Okhotsk orogenic belt, a group of rift basins developed during the Late Jurassic. In eastern Mongolia, the NE orientated extensional basins were controlled by the neogenic NE-structure. The contemporary basins in southern Mongolia and the neighboring areas in China were constrained by remobilization (inherited activation of the latitudinal or ENE-directional basement structures. Three stages can be recognized in the evolution of the Early–Middle Jurassic basins after reversal; the basins also experienced four episodes of reformation.