WorldWideScience

Sample records for abundance retrieval method

  1. Developing Atmospheric Retrieval Methods for Direct Imaging Spectroscopy of Gas Giants in Reflected Light. I. Methane Abundances and Basic Cloud Properties

    Science.gov (United States)

    Lupu, Roxana E.; Marley, Mark S.; Lewis, Nikole; Line, Michael; Traub, Wesley A.; Zahnle, Kevin

    2016-12-01

    Upcoming space-based coronagraphic instruments in the next decade will perform reflected light spectroscopy and photometry of cool directly imaged extrasolar giant planets. We are developing a new atmospheric retrieval methodology to help assess the science return and inform the instrument design for such future missions, and ultimately interpret the resulting observations. Our retrieval technique employs a geometric albedo model coupled with both a Markov chain Monte Carlo Ensemble Sampler (emcee) and a multimodal nested sampling algorithm (MultiNest) to map the posterior distribution. This combination makes the global evidence calculation more robust for any given model and highlights possible discrepancies in the likelihood maps. As a proof of concept, our current atmospheric model contains one or two cloud layers, methane as a major absorber, and a H2-He background gas. This 6-to-9 parameter model is appropriate for Jupiter-like planets and can be easily expanded in the future. In addition to deriving the marginal likelihood distribution and confidence intervals for the model parameters, we perform model selection to determine the significance of methane and cloud detection as a function of expected signal-to-noise ratio in the presence of spectral noise correlations. After internal validation, the method is applied to realistic spectra of Jupiter, Saturn, and HD 99492c, a model observing target. We find that the presence or absence of clouds and methane can be determined with high confidence, while parameter uncertainties are model dependent and correlated. Such general methods will also be applicable to the interpretation of direct imaging spectra of cloudy terrestrial planets.

  2. Developing Atmospheric Retrieval Methods for Direct Imaging Spectroscopy of Gas Giants in Reflected Light I: Methane Abundances and Basic Cloud Properties

    CERN Document Server

    Lupu, Roxana E; Lewis, Nikole; Line, Michael; Traub, Wesley A; Zahnle, Kevin

    2016-01-01

    Reflected light spectroscopy and photometry of cool, directly imaged extrasolar giant planets are expected to be performed in the next decade by space-based telescopes equipped with optical wavelength coronagraphs and integral field spectrographs, such as the Wide-Field Infrared Survey Telescope (WFIRST). We are developing a new atmospheric retrieval methodology to help assess the science return and inform the instrument design for such future missions, and ultimately interpret the resulting observations. Our retrieval technique employs a geometric albedo model coupled with both a Markov chain Monte Carlo Ensemble Sampler (emcee) and a multimodal nested sampling algorithm (MultiNest) to map the posterior distribution. This combination makes the global evidence calculation more robust for any given model, and highlights possible discrepancies in the likelihood maps. Here we apply this methodology to simulated spectra of cool giant planets. As a proof-of-concept, our current atmospheric model contains 1 or 2 cl...

  3. Numerical methods for phase retrieval

    CERN Document Server

    Osherovich, Eliyahu

    2012-01-01

    In this work we consider the problem of reconstruction of a signal from the magnitude of its Fourier transform, also known as phase retrieval. The problem arises in many areas of astronomy, crystallography, optics, and coherent diffraction imaging (CDI). Our main goal is to develop an efficient reconstruction method based on continuous optimization techniques. Unlike current reconstruction methods, which are based on alternating projections, our approach leads to a much faster and more robust method. However, all previous attempts to employ continuous optimization methods, such as Newton-type algorithms, to the phase retrieval problem failed. In this work we provide an explanation for this failure, and based on this explanation we devise a sufficient condition that allows development of new reconstruction methods---approximately known Fourier phase. We demonstrate that a rough (up to $\\pi/2$ radians) Fourier phase estimate practically guarantees successful reconstruction by any reasonable method. We also pres...

  4. A METHOD OF SHAPE ENCODING AND RETRIEVAL

    Institute of Scientific and Technical Information of China (English)

    Huang Xianglin; Song Lei; Shen Lansun

    2002-01-01

    A method of shape encoding and retrieval is proposed in this letter, which uses centripetal code to encode shape and extracts shape's convex for retrieval. For the rotation invariance and translation invariance of the centripetal code and the normalization of convex,the proposed retrieval method is similarity transform resistant, Experimental results confirm this capability.

  5. Abundance retrieval of hydrous minerals around the Mars Science Laboratory landing site in Gale crater, Mars

    Science.gov (United States)

    Lin, Honglei; Zhang, Xia; Shuai, Tong; Zhang, Lifu; Sun, Yanli

    2016-02-01

    The detection of hydrous minerals on Mars is of great importance for revealing the early water environment as well as possible biotic activity. However, few studies focus on abundance retrieval of hydrous minerals for some difficulties. In this paper, we studied the area around the Mars Science Laboratory (MSL) landing site, to identify hydrous minerals and retrieve their abundance. Firstly, the distribution of hydrous minerals was extracted using their hydration features. Then, a sparse unmixing algorithm was applied along with the CRISM spectral library to retrieve the abundance of hydrous minerals in this area. As a result, seven hydrous minerals were retrieved, i.e. actinolite, montmorillonite, saponite, jarosite, halloysite, szomolnokite and magnesite and, the total concentration of all hydrous minerals was as high as 40 vol% near the lower reaches of Mount Sharp. Our results were consistent with results from related research and the in-situ analysis of the MSL rover Curiosity.

  6. Retrieval algorithm for CO2 and CH4 column abundances from short-wavelength infrared spectral observations by the Greenhouse gases observing satellite

    Directory of Open Access Journals (Sweden)

    I. Morino

    2011-04-01

    Full Text Available The Greenhouse gases Observing SATellite (GOSAT was launched on 23 January 2009 to monitor the global distributions of carbon dioxide and methane from space. It has operated continuously since then. Here, we describe a retrieval algorithm for column abundances of these gases from the short-wavelength infrared spectra obtained by the Thermal And Near infrared Sensor for carbon Observation-Fourier Transform Spectrometer (TANSO-FTS. The algorithm consists of three steps. First, cloud-free observational scenes are selected by several cloud-detection methods. Then, column abundances of carbon dioxide and methane are retrieved based on the optimal estimation method. Finally, the retrieval quality is examined to exclude low-quality and/or aerosol-contaminated results. Most of the retrieval random errors come from instrumental noise. The interferences due to auxiliary parameters retrieved simultaneously with gas abundances are small. The evaluated precisions of the retrieved column abundances for single observations are less than 1% in most cases. The interhemispherical differences and temporal variation patterns of the retrieved column abundances show features similar to those of an atmospheric transport model.

  7. Retrieval algorithm for CO2 and CH4 column abundances from short-wavelength infrared spectral observations by the Greenhouse Gases Observing Satellite

    Directory of Open Access Journals (Sweden)

    I. Morino

    2010-11-01

    Full Text Available The Greenhouse gases Observing SATellite (GOSAT was launched on 23 January 2009 to monitor the global distributions of carbon dioxide and methane from space. It has operated continuously since then. Here we describe a retrieval algorithm for column abundances of these gases from the short-wavelength infrared spectra obtained by the Thermal And Near infrared Sensor for carbon Observation-Fourier Transform Spectrometer (TANSO-FTS. The algorithm consists of three steps. First, cloud-free observational scenes are selected by several cloud-detection methods. Then, column abundances of carbon dioxide and methane are retrieved based on the optimal estimation method. Finally, the retrieval quality is examined to exclude low-quality and/or aerosol-contaminated results. Most of the retrieval random errors come from the instrumental noise. The interferences by auxiliary parameters retrieved simultaneously with gas abundances are small. The evaluated precisions of the retrieved column abundances for single observations are less than 1% in most cases. The interhemispherical differences and the temporal variation patterns of the retrieved column abundances agree well with the current state of knowledge.

  8. An Image Retrieval Method Using DCT Features

    Institute of Scientific and Technical Information of China (English)

    樊昀; 王润生

    2002-01-01

    In this paper a new image representation for compressed domain image re-trieval and an image retrieval system are presented. To represent images compactly and hi-erarchically, multiple features such as color and texture features directly extracted from DCTcoefficients are structurally organized using vector quantization. To train the codebook, a newMinimum Description Length vector quantization algorithm is used and it automatically decidesthe number of code words. To compare two images using the proposed representation, a newefficient similarity measure is designed. The new method is applied to an image database with1,005 pictures. The results demonstrate that the method is better than two typical histogrammethods and two DCT-based image retrieval methods.

  9. Wave propagation retrieval method for chiral metamaterials

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    2010-01-01

    In this paper we present the wave propagation method for the retrieving of effective properties of media with circularly polarized eigenwaves, in particularly for chiral metamaterials. The method is applied for thick slabs and provides bulk effective parameters. Its strong sides are the absence...

  10. Evolutionary Computing Methods for Spectral Retrieval

    Science.gov (United States)

    Terrile, Richard; Fink, Wolfgang; Huntsberger, Terrance; Lee, Seugwon; Tisdale, Edwin; VonAllmen, Paul; Tinetti, Geivanna

    2009-01-01

    A methodology for processing spectral images to retrieve information on underlying physical, chemical, and/or biological phenomena is based on evolutionary and related computational methods implemented in software. In a typical case, the solution (the information that one seeks to retrieve) consists of parameters of a mathematical model that represents one or more of the phenomena of interest. The methodology was developed for the initial purpose of retrieving the desired information from spectral image data acquired by remote-sensing instruments aimed at planets (including the Earth). Examples of information desired in such applications include trace gas concentrations, temperature profiles, surface types, day/night fractions, cloud/aerosol fractions, seasons, and viewing angles. The methodology is also potentially useful for retrieving information on chemical and/or biological hazards in terrestrial settings. In this methodology, one utilizes an iterative process that minimizes a fitness function indicative of the degree of dissimilarity between observed and synthetic spectral and angular data. The evolutionary computing methods that lie at the heart of this process yield a population of solutions (sets of the desired parameters) within an accuracy represented by a fitness-function value specified by the user. The evolutionary computing methods (ECM) used in this methodology are Genetic Algorithms and Simulated Annealing, both of which are well-established optimization techniques and have also been described in previous NASA Tech Briefs articles. These are embedded in a conceptual framework, represented in the architecture of the implementing software, that enables automatic retrieval of spectral and angular data and analysis of the retrieved solutions for uniqueness.

  11. Method of and System for Information Retrieval

    DEFF Research Database (Denmark)

    2015-01-01

    This invention relates to a system for and a method (100) of searching a collection of digital information (150) comprising a number of digital documents (110), the method comprising receiving or obtaining (102) a search query, the query comprising a number of search terms, searching (103) an index...... (300) using the search terms thereby providing information (301) about which digital documents (110) of the collection of digital information (150) that contains a given search term and one or more search related metrics (302; 303; 304; 305; 306), ranking (105) at least a part of the search result......, a method of and a system for information retrieval or searching is readily provided that enhances the searching quality (i.e. the number of relevant documents retrieved and such documents being ranked high) when (also) using queries containing many search terms....

  12. KNOWLEDGE BASED METHODS FOR VIDEO DATA RETRIEVAL

    OpenAIRE

    S.Thanga Ramya; P. Rangarajan

    2011-01-01

    Large collections of publicly available video data grow day by day, the need to query this dataefficiently becomes significant. Consequently, content-based retrieval of video data turns out to be achallenging and important problem. This paper addresses the specific aspect of inferring semanticsautomatically from raw video data using different knowledge-based methods. In particular, this paperfocuses on three techniques namely, rules, Hidden Markov Models (HMMs), and Dynamic BayesianNetworks (...

  13. Combining Abundance/Temperature Retrieval with 3D Atmospheric Circulation Simulations of Hot Jupiters

    Science.gov (United States)

    Heng, Kevin

    2011-09-01

    The atmospheres of hot Jupiters are three-dimensional, non-linear entities and understanding them requires the construction of a hierarchy of models of varying sophistication. Since previous work has either focused on the atmospheric dynamics or implemented multi-band radiative transfer, a reasonable approach is to combine the treatment of 3D dynamics with dual-band radiative transfer, where the assumption is that the stellar irradiation and re-emitted radiation from the exoplanet are at distinct wavelengths. I report on the successful implementation of such a setup and demonstrate how it can be used to compute self-consistent temperature-pressure profiles on both the day and night sides of a hot Jupiter, as well as zonal-wind profiles, circulation cell patterns and the angular/temporal offset of the hotspot from the substellar point. In particular, the hotspot offset should aid us in distinguishing between different types of hot Jupiter atmospheres. Together with N. Madhusudhan, we combine the dual-band simulation technique with the abundance/temperature retrieval method of Madhusudhan & Seager, by empirically constraining a range of values for the broad-band opacities which are consistent with the current observations. The advantage of our novel method is that the range of opacities used improves with time as the observations get better. The ability to thoroughly, efficiently and systematically explore the interplay between atmospheric dynamics, radiation and synthetic spectra is an important step forward, as it prepares us for the theoretical interpretation of exoplanetary spectra which will be obtained by future space-based missions such as JWST and EChO. I acknowledge generous support from the Zwicky Prize Fellowship and the Star and Planet Formation Group (PI: Michael Meyer) at ETH Zurich.

  14. Global Abundance and Temperature Constraints via Joint Spectroscopic Phase Curve Retrievals

    Science.gov (United States)

    Line, Michael R.; Stevenson, Kevin B.; Bean, Jacob; Kreidberg, Laura; Fortney, Jonathan J.

    2016-01-01

    Spectroscopic thermal emission phase curves can provide us with a global view of an exoplanet's atmosphere. Different wavelengths probe different atmospheric depths whereas different phases probe different planetary longitudes. This in essence allows us to reconstruct the "3D" thermal and compositional structure of these atmospheres. In this contribution I will discuss the application of powerful atmospheric retrieval approaches to spectroscopic phase curve data, specifically the WFC3+Spitzer IRAC observations of the hot-Jupiter WASP-43b. First I will show the variation in thermal structures and molecular abundances with phase, assuming each phase is independent. Secondly, I will present a new framework for performing a joint retrieval on multiple phases simultaneously. In such a framework, I will test, via Bayesian hypothesis testing, a variety of assumptions. For instance, can the absorption features across all phases be explained with a global metallicity and C-to-O ratio under the assumption of thermochemical equilibrium? Can chemical quenching perturb the abundances on the cooler phases more than the hotter phases? Can we tell the difference? Can a global thermal structure "shape" explain all phases or is there structure variation with phase? Answering such questions are critical to understanding the complex interactions of atmospheric dynamics, chemical processes, and radiative energy balance in exoplanet atmospheres.

  15. Flexible method for Boolean information retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Salton, G.; Wu, H.

    1983-01-01

    A new flexible retrieval system is described which makes it possible to relax the strict conditions of Boolean query logic thereby retrieving useful items that are rejected in a conventional retrieval situation. The query structure inherent in the Boolean system is preserved, while at the same time weighted terms may be incorporated into both queries and stored documents; the retrieved output can also be ranked in strict similarity order with the user queries. A conventional retrieval system can be modified to make use of the flexible metric system. Laboratory tests indicate that the extended system produces better retrieval output than either the Boolean or the vector processing systems. 11 references.

  16. AN ONTOLOGY-BASED INTELLIGENT INFORMATION RETRIEVAL METHOD FOR DOCUMENT RETRIEVAL

    Directory of Open Access Journals (Sweden)

    POONAM YADAV

    2012-09-01

    Full Text Available The document retrieval is one of the fast growing and complex research area in the field of information retrieval. In this paper, we proposed an ontology-based method for document retrieval. The ontology defined in our proposed approach gives extra freedom to choose between the documents and thus give an accurate retrieval ofthe documents. The results and analysis of our proposed method showed expected results and a comparative analysis was subjected for analyzing the proposed method with an existing algorithm. The F-measure comparison showed the performance improvement of the proposed method with respect to the existing method.

  17. AN IMAGE RETRIEVAL METHOD BASED ON SPATIAL DISTRIBUTION OF COLOR

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Color histogram is now widely used in image retrieval. Color histogram-based image retrieval methods are simple and efficient but without considering the spatial distribution information of the color. To overcome the shortcoming of conventional color histogram-based image retrieval methods, an image retrieval method based on Radon Transform (RT) is proposed. In order to reduce the computational complexity,wavelet decomposition is used to compress image data. Firstly, images are decomposed by Mallat algorithm.The low-frequency components are then projected by RT to generate the spatial color feature. Finally the moment feature matrices which are saved along with original images are obtained. Experimental results show that the RT based retrieval is more accurate and efficient than traditional color histogram-based method in case that there are obvious objects in images. Further more, RT based retrieval runs significantly faster than the traditional color histogram methods.

  18. Case Retrieval Method of Multi-parameter for Customized Product

    Institute of Scientific and Technical Information of China (English)

    DING Junjian; TAN Shili; SONG Xiaofeng; WANG Meiting

    2006-01-01

    The CBR(Case-Based Reasoning) usually is been used to accomplish customized products by variant design or reusable design. In the CBR, retrieve is very important. A simple case retrieval method is been brought forward to retrieve a optimal prototype based on using inputted multi-parameters, it can be programmed easily. An example has been proved this method can find optimal prototype for new design task efficiently.

  19. A Semantic Retrieval Method Based on the Fuzzy Reasoning

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper gives a semantic fuzzy retrieval method of multimedia object,discusses the principle of fuzzy semantic retrieval technique,presents a fuzzy reasoning mechanism based on the knowledge base,and designs the relevant reasoning algorithms.Researchful results have innovative significance.

  20. Toward reliable estimates of abundance: comparing index methods to assess the abundance of a Mammalian predator.

    Directory of Open Access Journals (Sweden)

    Denise Güthlin

    Full Text Available Due to time and financial constraints indices are often used to obtain landscape-scale estimates of relative species abundance. Using two different field methods and comparing the results can help to detect possible bias or a non monotonic relationship between the index and the true abundance, providing more reliable results. We used data obtained from camera traps and feces counts to independently estimate relative abundance of red foxes in the Black Forest, a forested landscape in southern Germany. Applying negative binomial regression models, we identified landscape parameters that influence red fox abundance, which we then used to predict relative red fox abundance. We compared the estimated regression coefficients of the landscape parameters and the predicted abundance of the two methods. Further, we compared the costs and the precision of the two field methods. The predicted relative abundances were similar between the two methods, suggesting that the two indices were closely related to the true abundance of red foxes. For both methods, landscape diversity and edge density best described differences in the indices and had positive estimated effects on the relative fox abundance. In our study the costs of each method were of similar magnitude, but the sample size obtained from the feces counts (262 transects was larger than the camera trap sample size (88 camera locations. The precision of the camera traps was lower than the precision of the feces counts. The approach we applied can be used as a framework to compare and combine the results of two or more different field methods to estimate abundance and by this enhance the reliability of the result.

  1. Ellipse-based shape description and retrieval method

    Institute of Scientific and Technical Information of China (English)

    李向阳; 潘云鹤

    2002-01-01

    Using a group of ellipses to approach the shape contour, a new shape retrieval method is presented in this paper. In order to keep shape-based retrieval invariant to its position, orientation and size, the shape normalization method is presented. From our research, any closed shape contour can be uniquely decomposed into a group of ellipses, and the original shape contour can be re-constructed using the decomposed ellipses. The ellipse-based shape description and similar retrieval method is introduced in this paper. Based on ellipse's contribution to shape contour, the decomposed ellipses are parted into low-order ellipses and high-order ellipses. The low-order ellipses measure the macroscopic feature of a shape contour, and the high-order ellipses measure the microscopic feature. The two-phase shape matching method is given. Through the experiment test, our method has better shape retrieval effect.

  2. The Water Abundance of the Directly Imaged Substellar Companion κ And b Retrieved from a Near Infrared Spectrum

    Science.gov (United States)

    Todorov, Kamen O.; Line, Michael R.; Pineda, Jaime E.; Meyer, Michael R.; Quanz, Sascha P.; Hinkley, Sasha; Fortney, Jonathan J.

    2016-05-01

    Spectral retrieval has proven to be a powerful tool for constraining the physical properties and atmospheric compositions of extrasolar planet atmospheres based on observed spectra, primarily for transiting objects but also for directly imaged planets and brown dwarfs. Despite its strengths, this approach has been applied to only about a dozen targets. Determining the abundances of the main carbon- and oxygen-bearing compounds in a planetary atmosphere can lead to the C/O ratio of the object, which is crucial for understanding its formation and migration history. We present a retrieval analysis of the published near-infrared spectrum of κ \\quad {Andromedae} b, a directly imaged substellar companion to a young B9 star. We fit the emission spectrum model utilizing a Markov Chain Monte Carlo algorithm. We estimate the abundance of water vapor, and its uncertainty, in the atmosphere of the object. In addition, we place an upper limit on the abundance of CH4. We qualitatively compare our results with studies that have applied model retrieval on multiband photometry and emission spectroscopy of hot Jupiters (extrasolar giant planets with orbital periods of several days) and the directly imaged giant planet HR 8799b.

  3. Oxygen Abundance Methods in SDSS: View from Modern Statistics

    Indian Academy of Sciences (India)

    Fei Shi; Gang Zhao; James Wicker

    2010-09-01

    Our purpose is to find which is the most reliable one among various oxygen abundance determination methods. We will test the validity of several different oxygen abundance determination methods using methods of modern statistics. These methods include Bayesian analysis and information scoring. We will analyze a sample of ∼ 6000 HII galaxies from the Sloan Digital Sky Survey (SDSS) spectroscopic observations data release four. All methods that we used drew the same conclusion that the method is a more reliable oxygen abundance determination method than the Bayesian metallicity method under the existing telescope ability. The ratios of the likelihoods between the different kinds of methods tell us that the , , and 32 methods are consistent with each other because the and 32 methods are calibrated by method. The Bayesian and 23 methods are consistent with each other because both are calibrated by a galaxy model. In either case, the 2 method is an unreliable method.

  4. Ionized Gaseous Nebulae Abundance Determination from the Direct Method

    Science.gov (United States)

    Pérez-Montero, Enrique

    2017-04-01

    This tutorial explains the procedure used to analyze an optical emission-line spectrum produced by a nebula ionized by massive star formation. Particularly, the methodology used to derive physical properties, such as electron density and temperature, and the ionic abundances of the most representative elements whose emission lines are present in the optical spectrum is described. The main focus is on the direct method, which is based on the measurement of the electron temperature to derive the abundances, given that the ionization and thermal equilibrium of the ionized gas is dominated by the metallicity. The ionization correction factors used to obtain total abundances from the abundances of some of their ions are also given. Finally, some strong-line methods to derive abundances are described. Such methods are used when no estimation of the temperature can be derived, but which can be consistent with the direct method if they are empirically calibrated.

  5. A retrieval and validation method for shelterbelt vegetation fraction

    Institute of Scientific and Technical Information of China (English)

    DENG Rong-xin; WANG Wen-juan; LI Ying; ZHAO Dong-bao

    2013-01-01

    Shelterbelts are important in defending against natural disaster and maintaining ecological balances in farmland.Understanding of the shelterbelt vegetation fraction is fundamental to regional research of shelterbelts using remote sensing.We used SPOT5 imagery with 10×10m spatial resolution in combination with knowledge of the characteristics of shelterbelts to develop a method for retrieval of the vegetation fraction of shelterbelts by the pixel un-mixing model.We then used the method to retrieve values for shelterbelts in study area.By combining the parameters of photographic images with characteristics of shelterbelts,we developed a method for measuring the vegetation fraction of shelterbelts based on an advanced photographic method.We then measured the actual values to validate the retrieval result.The multiple correlation coefficients between the retrieved and measured values were 0.715.Our retrieval and measuring methods presented in this paper accurately reflect field conditions.We suggest that this method is useful to describe shelterbelt structure using remote sensing.

  6. The Water Abundance of the Directly Imaged Substellar Companion {\\kappa} And b Retrieved from a Near Infrared Spectrum

    CERN Document Server

    Todorov, Kamen O; Pineda, Jaime E; Meyer, Michael R; Quanz, Sascha P; Hinkley, Sasha; Fortney, Jonathan J

    2015-01-01

    Recently, spectral retrieval has proven to be a powerful tool for constraining the physical properties and atmospheric compositions of extrasolar planet atmospheres from observed spectra, primarily for transiting objects but also increasingly for directly imaged planets and brown dwarfs. Despite its strengths, this approach has been applied to only about a dozen targets. Determining the abundances of the main carbon and oxygen-bearing compounds in a planetary atmosphere can lead to the C/O ratio of the object, which is crucial in understanding its formation and migration history. We present a retrieval analysis on the published near-infrared spectrum of {\\kappa} And b, a directly imaged substellar companion to a young B9 star. We fit the emission spectrum model utilizing a Markov Chain Monte Carlo algorithm. We estimate the abundance of water vapor, and its uncertainty, in the atmosphere of the object. We also place upper limits on the abundances of carbon dioxide and methane and constrain the pressure-temper...

  7. Efficient Methods to Assimilate Satellite Retrievals Based on Information Content. Part 2; Suboptimal Retrieval Assimilation

    Science.gov (United States)

    Joiner, J.; Dee, D. P.

    1998-01-01

    One of the outstanding problems in data assimilation has been and continues to be how best to utilize satellite data while balancing the tradeoff between accuracy and computational cost. A number of weather prediction centers have recently achieved remarkable success in improving their forecast skill by changing the method by which satellite data are assimilated into the forecast model from the traditional approach of assimilating retrievals to the direct assimilation of radiances in a variational framework. The operational implementation of such a substantial change in methodology involves a great number of technical details, e.g., pertaining to quality control procedures, systematic error correction techniques, and tuning of the statistical parameters in the analysis algorithm. Although there are clear theoretical advantages to the direct radiance assimilation approach, it is not obvious at all to what extent the improvements that have been obtained so far can be attributed to the change in methodology, or to various technical aspects of the implementation. The issue is of interest because retrieval assimilation retains many practical and logistical advantages which may become even more significant in the near future when increasingly high-volume data sources become available. The central question we address here is: how much improvement can we expect from assimilating radiances rather than retrievals, all other things being equal? We compare the two approaches in a simplified one-dimensional theoretical framework, in which problems related to quality control and systematic error correction are conveniently absent. By assuming a perfect radiative transfer model and perfect knowledge of radiance and background error covariances, we are able to formulate a nonlinear local error analysis for each assimilation method. Direct radiance assimilation is optimal in this idealized context, while the traditional method of assimilating retrievals is suboptimal because it

  8. Chiral metamaterials characterisation using the wave propagation retrieval method

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Lavrinenko, Andrei; Malureanu, Radu

    2010-01-01

    In this presentation we extend the wave propagation method for the retrieval of the effective properties to the case of chiral metamaterials with circularly polarised eigenwaves. The method is unambiguous, simple and provides bulk effective parameters. Advantages and constraints are discussed...

  9. Which literature retrieval method is most effective for GPs?

    NARCIS (Netherlands)

    Verhoeven, A.A.H.; Boerma, E.J.; Meyboom-de Jong, B.

    2000-01-01

    Background. Evidence-based medicine requires new skills of physicians, including literature searching. Objective. To determine which literature retrieving method is most effective for GPs: the printed Index Medicus; Medline through Grateful Med; or Medline on CD-ROM. Methods. The design was a random

  10. A flower image retrieval method based on ROI feature

    Institute of Scientific and Technical Information of China (English)

    洪安祥; 陈刚; 李均利; 池哲儒; 张亶

    2004-01-01

    Flower image retrieval is a very important step for computer-aided plant species recognition. In this paper, we propose an efficient segmentation method based on color clustering and domain knowledge to extract flower regions from flower images. For flower retrieval, we use the color histogram of a flower region to characterize the color features of flower and two shape-based features sets, Centroid-Contour Distance (CCD) and Angle Code Histogram (ACH), to characterize the shape features of a flower contour. Experimental results showed that our flower region extraction method based on color clustering and domain knowledge can produce accurate flower regions. Flower retrieval results on a database of 885 flower images collected from 14 plant species showed that our Region-of-Interest (ROI) based retrieval approach using both color and shape features can perform better than a method based on the global color histogram proposed by Swain and Ballard (1991) and a method based on domain knowledge-driven segmentation and color names proposed by Das et al.(1999).

  11. A flower image retrieval method based on ROI feature

    Institute of Scientific and Technical Information of China (English)

    洪安祥; 陈刚; 李均利; 池哲儒; 张亶

    2004-01-01

    Flower image retrieval is a very important step for computer-aided plant species recognition.In this paper,we propose an efficient segmentation method based on color clustering and domain knowledge to extract flower regions from flower images.For flower retrieval,we use the color histogram of a flower region to characterize the color features of flower and two shape-based features sets,Centroid-Contour Distance(CCD)and Angle Code Histogram(ACH),to characterize the shape features of a flower contour.Experimental results showed that our flower region extraction method based on color clustering and domain knowledge can produce accurate flower regions.Flower retrieval results on a database of 885 flower images collected from 14 plant species showed that our Region-of-Interest(ROD based retrieval approach using both color and shape features can perform better than a method based on the global color histogram proposed by Swain and Ballard(1991)and a method based on domain knowledge-driven segmentation and color names proposed by Das et al.(1999).

  12. Retrievals of the Abundances of Acetylene and other Hydrocarbons in Titan's Upper Atmosphere

    Science.gov (United States)

    Fan, Siteng; Shemansky, D. E.; Yung, Yuk

    2016-10-01

    Acetylene abundance in the Titan upper atmosphere has been extracted from Cassini Ultraviolet Imaging Spectrograph (UVIS) stellar occultations. The data reduction process is based on simulation of the discrete spectral absorption in the far ultraviolet (FUV) region between 110 and 190 nm. Pointing drift is corrected by instrument simulation of the stellar image location on the instrument detector. Latitude and seasonal dependence of the vertical profiles has been examined. The observed spectra have been compared to atmospheric chemical model calculations (KINETICS) by predicting the occultation spectra, allowing the imposition of constraints on the model, and directly establishing the level of uncertainty in the extraction process. Hydrocarbon and nitrile vertical profiles have been extracted, with limits set on the precursors to aerosols. Aerosol continuum spectral structure is recognized in the extinction spectra, but physical chemistry modeling of aerosol precursors to date indicate higher abundances than the upper limits set by observation.

  13. Fuzzy-Based XML Knowledge Retrieval Methods in Edaphology

    Directory of Open Access Journals (Sweden)

    K. Naresh kumar

    2016-05-01

    Full Text Available In this paper, we propose a proficient method for knowledge management in Edaphology to assist the edaphologists and those related with agriculture in a big way. The proposed method mainly consists two sections of which the first one is to build the knowledge base using XML and the latter part deals with information retrieval by searching using fuzzy. Initially, the relational database is converted to the XML database. The paper discusses two algorithms, one is when the soil characteristics are inputted to have the plant list and in the other, plant names are inputted to have the soil characteristics suited for the plant. While retrieving the query result, the crisp numerical values are converted to fuzzy using the triangular fuzzy membership function and matched to those in database. And those which satisfy are added to the result list and subsequently the frequency is found out to rank the result list so as to obtain the final sorted list. Performance metrics used in order to evaluate the method and compare it to baseline paper are number of plants retrieved, ranking efficiency, and computation time and memory usage. Results obtained proved the validity of the method and the method obtained average computation time of 0.102 seconds and average memory usage of 2486 Kb, which all are far better than the previous method results.

  14. Improved ground-based FTS measurement for column abundance CO2 retrievals(Conference Presentation)

    Science.gov (United States)

    Goo, Tae-Young

    2016-10-01

    The National Institute of Meteorological Sciences has operated a ground-based Fourier Transform Spectrometer (FTS) at Anmyeondo, Korea since December 2012. Anmyeondo FTS site is a designated operational station of Total Carbon Column Observing Network (TCCON) and belongs to regional Global Atmosphere Watch observatory. A Bruker IFS-125HR model, which has a significantly high spectral resolution by 0.02 cm-1, is employed and instrument specification is almost same as the TCCON configuration. such as a spectrum range of 3,800 16,000 cm-1, a resolution of 1 cm-1, InGaAs and Si-Diode detectors and CaF2 beam splitter. It is found that measured spectra have a good agreement with simulated spectra. In order to improve the spectral accuracy and stability, The Operational Automatic System for Intensity of Sunray (OASIS) has been developed. The OASIS can provide consistent photon energy optimized to detector range by controlling the diameter of solar beam reflected from the mirror of suntracker. As a result, monthly modulation efficiency (ME), which indicates the spectral accuracy of FTS measurement, has been recorded the vicinity of 99.9% since Feb 2015. The ME of 98% is regarded as the error of 0.1% in the ground-based in-situ CO2 measurement. Total column abundances of CO2 and CH4 during 2015 are estimated by using GGG v14 and compared with ground-based in-situ CO2 and CH4 measurements at the height of 86 m above sea level. The seasonality of CO2 is well captured by both FTS and in-situ measurements while there is considerable difference on the amplitude of CO2 seasonal variation due to the insensitivity of column CO2 to the surface carbon cycle dynamics in nature as well as anthropogenic sources. Total column CO2 and CH4 approximately vary from 395 ppm to 405 ppm and from 1.82 ppm to 1.88 ppm, respectively. It should be noted that few measurements obtained in July to August because of a lot of cloud and fog. It is found that enhancement of CH4 from the FTS at Anmyeondo

  15. A modified phase-coding method for absolute phase retrieval

    Science.gov (United States)

    Xing, Y.; Quan, C.; Tay, C. J.

    2016-12-01

    Fringe projection technique is one of the most robust tools for three dimensional (3D) shape measurement. Various fringe projection methods have been proposed for addressing different issues in profilometry and phase-coding is one such technique employed to determine fringe orders for absolute phase retrieval. However this method is prone to fringe order error, while dealing with high-frequency fringes. This paper studies phase error introduced by system non-linearity in phase-coding and provides a mathematical model to obtain the maximum number of achievable codewords in a given scheme. In addition, a modified phase-coding method is also proposed for phase error compensation. Experimental study validates the theoretical analysis on the maximum number of achievable codewords and the performance of the modified phase-coding method is also illustrated.

  16. Accurate LAI retrieval method based on PROBA/CHRIS data

    Directory of Open Access Journals (Sweden)

    W. Fan

    2009-11-01

    Full Text Available Leaf area index (LAI is one of the key structural variables in terrestrial vegetation ecosystems. Remote sensing offers a chance to derive LAI in regional scales accurately. Variations of background, atmospheric conditions and the anisotropy of canopy reflectance are three factors that can strongly restrain the accuracy of retrieved LAI. Based on the hybrid canopy reflectance model, a new hyperspectral directional second derivative method (DSD is proposed in this paper. This method can estimate LAI accurately through analyzing the canopy anisotropy. The effect of the background can also be effectively removed. So the inversion precision and the dynamic range can be improved remarkably, which has been proved by numerical simulations. As the derivative method is very sensitive to the random noise, we put forward an innovative filtering approach, by which the data can be de-noised in spectral and spatial dimensions synchronously. It shows that the filtering method can remove the random noise effectively; therefore, the method can be performed to the remotely sensed hyperspectral image. The study region is situated in Zhangye, Gansu Province, China; the hyperspectral and multi-angular image of the study region has been acquired from Compact High-Resolution Imaging Spectrometer/Project for On-Board Autonomy (CHRIS/PROBA, on 4 and 14 June 2008. After the pre-processing procedures, the DSD method was applied, and the retrieve LAI was validated by the ground truth of 11 sites. It shows that by applying innovative filtering method, the new LAI inversion method is accurate and effective.

  17. CA光盘版检索方法与技巧%Methods and Skills of Retrieving CA on CD

    Institute of Scientific and Technical Information of China (English)

    谷雪蔷; 刘蜀仁

    2001-01-01

    Chemical Abstracts (CA) is widely used all over the world. In this article, the methods and skills of retrieving CA on CD are studied. Methods of combining CA on CD retrieval with Dialog online retrieval are also described.

  18. Mathematical, Logical, and Formal Methods in Information Retrieval: An Introduction to the Special Issue.

    Science.gov (United States)

    Crestani, Fabio; Dominich, Sandor; Lalmas, Mounia; van Rijsbergen, Cornelis Joost

    2003-01-01

    Discusses the importance of research on the use of mathematical, logical, and formal methods in information retrieval to help enhance retrieval effectiveness and clarify underlying concepts of information retrieval. Highlights include logic; probability; spaces; and future research needs. (Author/LRW)

  19. A method for semantic-based image retrieval

    Science.gov (United States)

    Liu, Hengwen; Tong, Hengqing; Tong, Qiaoling

    2009-10-01

    The most existed content-based image retrieval systems use traditional low-level features such as color, texture and shape to describe the image content, which are usually represented by statistic data. Actually, there are big differences between these statistic data and the image content which people understand. Therefore, how to describe image and to make it coincide with people's understanding become the key point of improving retrieval accuracy. In the point of cognition, people's understanding and description of image content is on semantic level. How to reduce 'semantic gap', how to accurately represent content semantic of image and retrieval intention of people becomes important and critical. One effective ways has been proposed to solve the problem: semantic image retrieval based on ontology. In this paper a new image retrieval system based on ontology and relevant feedback was presented. The ontology was used to describe the semantic features of images and then retrieve the images.

  20. New Retrieval Method Based on Relative Entropy for Language Modeling with Different Smoothing Methods

    Institute of Scientific and Technical Information of China (English)

    Huo Hua; Liu Junqiang; Feng Boqin

    2006-01-01

    A language model for information retrieval is built by using a query language model to generate queries and a document language model to generate documents. The documents are ranked according to the relative entropies of estimated document language models with respect to the estimated query language model. Two popular and relatively efficient smoothing methods, the JelinekMercer method and the absolute discounting method, are used to smooth the document language model in estimation of the document language. A combined model composed of the feedback document language model and the collection language model is used to estimate the query model. A performacne comparison between the new retrieval method and the existing method with feedback is made,and the retrieval performances of the proposed method with the two different smoothing techniques are evaluated on three Text Retrieval Conference (TREC) data sets. Experimental results show that the method is effective and performs better than the basic language modeling approach; moreover, the method using the Jelinek-Mercer technique performs better than that using the absolute discounting technique, and the perfomance is sensitive to the smoothing paramters.

  1. Comparison of the Assimilation of Compact Phase Space Retrievals (CPSRs) with Conventional Retrieval Assimilation Methods for MOPITT CO in WRF-Chem/DART

    Science.gov (United States)

    Mizzi, A. P.; Arellano, A. F.; Edwards, D. P.; Anderson, J. L.

    2015-12-01

    We introduced "compact phase space retrievals" (CPSRs) for assimilating atmospheric composition observations in Mizzi et al. (2015). CPSRs address many of the challenges associated with assimilating retrievals by: (i) removing the contribution of the retrieval prior, (ii) diagonalizing the associated error covariance, and (iii) compacting the phase space retrievals. Mizzi et al. (2015) showed that the CPSRs reduced assimilation computational costs by approximately one-third while maintaining the relevant forecast skill metrics. In this paper, we examine phase space retrievals and compare CPSRs to more conventional retrieval assimilation methods. Specifically we compare the assimilation of CPSRs with that of (i) raw retrievals where the observation error is based on the diagonal of the retrieval error covariance, (ii) quasi-optimal retrievals (QORs) where the observation error is determined as (i), and (iii) QORs where the observation error is based on an SVD-based transform of the error covariance. Method (i) is the easiest to interpret because the assimilation occurs in retrieval space. Method (ii) explicitly removes the retrieval prior term's contribution but is more difficult to interpret because the assimilated observations are residuals. Finally, method (iii) is the phase space retrieval algorithm of Migliorini et al. (2008). We consider two variants: (i) withholding the inverse square scaling and (ii) using phase space filtering for optimization. We apply those methods to month-long forecast/assimilation experiments with continuous cycling.

  2. An Effective Method of Image Retrieval using Image Mining Techniques

    CERN Document Server

    Kannan, A; Anbazhagan, N; 10.5121/ijma.2010.2402

    2010-01-01

    The present research scholars are having keen interest in doing their research activities in the area of Data mining all over the world. Especially, [13]Mining Image data is the one of the essential features in this present scenario since image data plays vital role in every aspect of the system such as business for marketing, hospital for surgery, engineering for construction, Web for publication and so on. The other area in the Image mining system is the Content-Based Image Retrieval (CBIR) which performs retrieval based on the similarity defined in terms of extracted features with more objectiveness. The drawback in CBIR is the features of the query image alone are considered. Hence, a new technique called Image retrieval based on optimum clusters is proposed for improving user interaction with image retrieval systems by fully exploiting the similarity information. The index is created by describing the images according to their color characteristics, with compact feature vectors, that represent typical co...

  3. Retrieval Method of Scopus Database by Concrete Examples%Scopus数据库检索例析

    Institute of Scientific and Technical Information of China (English)

    佟岩; 于占洋; 毕玉侠

    2011-01-01

    The paper concretely introduces the retrieval fields,document types of Scopus database as well as the retrieval methods including basic retrieval,author retrieval,institution retrieval,advanced retrieval,source retrieval and so on,preliminary discusses the intelligence service function of Scopus in scientific research.%通过具体实例详细介绍Scopus数据库可供检索的字段、文献类型以及基本检索、作者检索、机构检索、高级检索、来源检索等检索方法,初步探讨Scopus在科研方面的智能服务功能。

  4. An Image Retrieval Method Based on Color and Texture Features

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The technique of image retrieval is widely used in science experiment, military affairs, public security,advertisement, family entertainment, library and so on. The existing algorithms are mostly based on the characteristics of color, texture, shape and space relationship. This paper introduced an image retrieval algorithm, which is based on the matching of weighted EMD(Earth Mover's Distance) distance and texture distance. EMD distance is the distance between the histograms of two images in HSV(Hue, Saturation, Value) color space, and texture distance is the L1 distance between the texture spectra of two images. The experimental results show that the retrieval rate can be increased obviously by using the proposed algorithm.

  5. Antigen retrieval techniques in immunohistochemistry: comparison of different methods.

    Science.gov (United States)

    Pileri, S A; Roncador, G; Ceccarelli, C; Piccioli, M; Briskomatis, A; Sabattini, E; Ascani, S; Santini, D; Piccaluga, P P; Leone, O; Damiani, S; Ercolessi, C; Sandri, F; Pieri, F; Leoncini, L; Falini, B

    1997-09-01

    Routine sections of normal and pathological samples fixed in 10 per cent buffered formalin or B5, including EDTA-decalcified bone-marrow biopsies, were tested with 61 antibodies following heating in three different fluids: 0.01 M citrate buffer (pH 6.0), 0.1 M Tris-HCl (pH 8.0), and 1 mM EDTA-NaOH solution (pH 8.0). The sections underwent either three cycles of microwave treatment (5 min each) or pressure cooking for 1-2 min. The alkaline phosphatase/anti-alkaline phosphatase (APAAP) technique was used as the standard detection method; with 16 antibodies a slightly modified streptavidin-biotin complex (SABC)-immunoperoxidase technique was applied in parallel. The results obtained were compared with those observed without any antigen retrieval (AR), or following section digestion with 0.05 per cent protease XIV at 37 degrees C for 5 min. Chess-board titration tests showed that all antibodies but one profited by AR. Protease XIV digestion represented the gold standard for five antibodies, while 55 produced optimal results following the application of heat-based AR. By comparison with the other fluids, EDTA appeared to be superior in terms of both staining intensity and the number of marked cells. These results were independent of tissue processing, immunohistochemical approach, and heating device. Pressure cooking was found to be more convenient on practical grounds, as it allowed the simultaneous handling of a large number of slides and a time saving of 1 min 30 s, representing the proper time for the treatment.

  6. The optimal retrieval of ocean color constituent concentrations based on the variational method

    Institute of Scientific and Technical Information of China (English)

    YU Hong; FAN Zhe; DU Hua-dong

    2013-01-01

    In this paper,a new approach to the optimal retrieval of the ocean color based on the variational method is developed by setting up a rational target functional combining with the Broydor Fletcher,Goldfarb,Shanno (BFGS) optimal algorithm.The numerical tests and the exemplary retrievals are carried out and compared with the statistical retrievals and the optimal retrievals based on the genetic algorithm.The results show that this approach enjoys a higher accuracy as compared to the statistical method and a higher efficiency as compared to the genetic algorithm.The optimal retrieval method presented in this paper provides a new idea for the ocean color inversion and could also be used as a reference for the direct assimilation of the satellite data into the ecological models.

  7. The Monte Carlo Method and the Evaluation of Retrieval System Performance.

    Science.gov (United States)

    Burgin, Robert

    1999-01-01

    Introduces the Monte Carlo method which is shown to represent an attractive alternative to the hypergeometric model for identifying the levels at which random retrieval performance is exceeded in retrieval test collections and for overcoming some of the limitations of the hypergeometric model. Practical matters to consider when employing the Monte…

  8. An Integrating VAP Method for Single-Doppler Radar Wind Retrieval

    Institute of Scientific and Technical Information of China (English)

    LIANG Xudong; WANG Bin

    2009-01-01

    Some traditional methods, such as the velocity-azimuth display (VAD) and the velocity-azimuth pro-cessing (VAP), have been widely used to retrieve the 3-D wind field from single-Doppler radar data because of their relative conceptual and practical simplicity. The advantage of VAD is that it is not affected by small-scale perturbations of the radial wind along the azimuth, to which the VAP method is very sensitive. Nevertheless, the spatial resolution of the VAD method is very poor compared to the VAP method. We show, in this study, that these two retrieval methods are actually related with each other and they are two special applications of a retrieval function based on the azimuthal uniform-wind assumption for a given azimuthal interval [θ1,θ2]. When using this retrieval function to retrieve wind fields, the azimuthal interval used in retrieval can be adjusted according to the requirement of smoothness or resolution. The larger (smaller) the azimuthal interval is, the coarser (finer) the horizontal resolution of retrieved wind field is, and the more insensitive (sensitive) the retrieval method is to small-scale perturbations. Because the full information within the azimuthal interval [θ1,θ2], instead of the information at two terminal points only, i.e., azimuths θ1 and θ2, is used to retrieve the wind fields, this method is referred to as the integrating VAP (IVAP) method, wherein the horizontal wind field is retrieved by using the Doppler velocity over the part of circumference, delimited by the given azimuthal interval times the scan radius. By contrast, the VAP method uses only the velocities at two terminal points of the given azimuthal interval. Therefore, the IVAP method has a filtering function, and the filtering rate can be controlled by adjusting the azimuthal interval. The filter such as that used in the pre-processing of the VAP method is no longer necessary for the IVAP method. When the retrieval azimuthal interval is as large as a whole

  9. Retrieval of mesospheric electron densities using an optimal estimation inverse method

    Science.gov (United States)

    Grant, J.; Grainger, R. G.; Lawrence, B. N.; Fraser, G. J.; von Biel, H. A.; Heuff, D. N.; Plank, G. E.

    2004-03-01

    We present a new method to determine mesospheric electron densities from partially reflected medium frequency radar pulses. The technique uses an optimal estimation inverse method and retrieves both an electron density profile and a gradient electron density profile. As well as accounting for the absorption of the two magnetoionic modes formed by ionospheric birefringence of each radar pulse, the forward model of the retrieval parameterises possible Fresnel scatter of each mode by fine electronic structure, phase changes of each mode due to Faraday rotation and the dependence of the amplitudes of the backscattered modes upon pulse width. Validation results indicate that known profiles can be retrieved and that χ2 tests upon retrieval parameters satisfy validity criteria. Application to measurements shows that retrieved electron density profiles are consistent with accepted ideas about seasonal variability of electron densities and their dependence upon nitric oxide production and transport.

  10. Histogrammatic Method for Determining Relative Abundance of Input Gas Pulse

    Science.gov (United States)

    Mandrake, Lukas; Bornstein, Benjamin J.; Madzunkov, Stojan; MacAskill, John A.

    2012-01-01

    To satisfy the Major Constituents Analysis (MCA) requirements for the Vehicle Cabin Atmosphere Monitor (VCAM), this software analyzes the relative abundance ratios for N2, O2, Ar, and CO2 as a function of time and constructs their best-estimate mean. A histogram is first built of all abundance ratios for each of the species vs time. The abundance peaks corresponding to the intended measurement and any obfuscating background are then separated via standard peak-finding techniques in histogram space. A voting scheme is then used to include/exclude this particular time sample in the final average based on its membership to the intended measurement or the background population. This results in a robust and reasonable estimate of the abundance of trace components such as CO2 and Ar even in the presence of obfuscating backgrounds internal to the VCAM device. VCAM can provide a means for monitoring the air within the enclosed environments, such as the ISS (International Space Station), Crew Exploration Vehicle (CEV), a Lunar Habitat, or another vehicle traveling to Mars. Its miniature pre-concentrator, gas chromatograph (GC), and mass spectrometer can provide unbiased detection of a large number of organic species as well as MCA analysis. VCAM s software can identify the concentration of trace chemicals and whether the chemicals are on a targeted list of hazardous compounds. This innovation s performance and reliability on orbit, along with the ground team s assessment of its raw data and analysis results, will validate its technology for future use and development.

  11. Image Retrieval Method Using Top-surf Descriptor

    CERN Document Server

    Ji, Ye

    2011-01-01

    This report presents the results and details of a content-based image retrieval project using the Top-surf descriptor. The experimental results are preliminary, however, it shows the capability of deducing objects from parts of the objects or from the objects that are similar. This paper uses a dataset consisting of 1200 images of which 800 images are equally divided into 8 categories, namely airplane, beach, motorbike, forest, elephants, horses, bus and building, while the other 400 images are randomly picked from the Internet. The best results achieved are from building category.

  12. An Effective Method of Image Retrieval using Image Mining Techniques

    OpenAIRE

    Kannan, A.; Dr.V.Mohan; Dr.N.Anbazhagan

    2010-01-01

    The present research scholars are having keen interest in doing their research activities in the area of Data mining all over the world. Especially, [13]Mining Image data is the one of the essential features in this present scenario since image data plays vital role in every aspect of the system such as business for marketing, hospital for surgery, engineering for construction, Web for publication and so on. The other area in the Image mining system is the Content-Based Image Retrieval (CB...

  13. A phase retrieval method of interferograms add-subtracting based on two-step phase shifting.

    Science.gov (United States)

    Xu, Yuanyuan; Wang, Yawei; Ji, Ying; Jin, Weifeng; Bu, Min; Shang, Xuefu

    2014-01-01

    A phase retrieval method is introduced in quantitative phase imaging (QPI) based on two-step phase-shifting technique. By acquiring two measured interferograms and calculating the addition and subtraction between them, the quantitative phase information can be directly retrieved. This method is illustrated by both theory and simulation experiments of a ball. The results of the simulation and the experiment of the red blood cell show a good agreement, demonstrating its application for studying cells.

  14. Quantitative interferometric microscopy with two dimensional Hilbert transform based phase retrieval method

    Science.gov (United States)

    Wang, Shouyu; Yan, Keding; Xue, Liang

    2017-01-01

    In order to obtain high contrast images and detailed descriptions of label free samples, quantitative interferometric microscopy combining with phase retrieval is designed to obtain sample phase distributions from fringes. As accuracy and efficiency of recovered phases are affected by phase retrieval methods, thus approaches owning higher precision and faster processing speed are still in demand. Here, two dimensional Hilbert transform based phase retrieval method is adopted in cellular phase imaging, it not only reserves more sample specifics compared to classical fast Fourier transform based method, but also overcomes disadvantages of traditional algorithm according to Hilbert transform which is a one dimensional processing causing phase ambiguities. Both simulations and experiments are provided, proving the proposed phase retrieval approach can acquire quantitative sample phases with high accuracy and fast speed.

  15. Adjusted Levenberg-Marquardt method application to methene retrieval from IASI/METOP spectra

    Science.gov (United States)

    Khamatnurova, Marina; Gribanov, Konstantin

    2016-04-01

    Levenberg-Marquardt method [1] with iteratively adjusted parameter and simultaneous evaluation of averaging kernels together with technique of parameters selection are developed and applied to the retrieval of methane vertical profiles in the atmosphere from IASI/METOP spectra. Retrieved methane vertical profiles are then used for calculation of total atmospheric column amount. NCEP/NCAR reanalysis data provided by ESRL (NOAA, Boulder,USA) [2] are taken as initial guess for retrieval algorithm. Surface temperature, temperature and humidity vertical profiles are retrieved before methane vertical profile retrieval for each selected spectrum. Modified software package FIRE-ARMS [3] were used for numerical experiments. To adjust parameters and validate the method we used ECMWF MACC reanalysis data [4]. Methane columnar values retrieved from cloudless IASI spectra demonstrate good agreement with MACC columnar values. Comparison is performed for IASI spectra measured in May of 2012 over Western Siberia. Application of the method for current IASI/METOP measurements are discussed. 1.Ma C., Jiang L. Some Research on Levenberg-Marquardt Method for the Nonlinear Equations // Applied Mathematics and Computation. 2007. V.184. P. 1032-1040 2.http://www.esrl.noaa.gov/psdhttp://www.esrl.noaa.gov/psd 3.Gribanov K.G., Zakharov V.I., Tashkun S.A., Tyuterev Vl.G.. A New Software Tool for Radiative Transfer Calculations and its application to IMG/ADEOS data // JQSRT.2001.V.68.№ 4. P. 435-451. 4.http://www.ecmwf.int/http://www.ecmwf.int

  16. Optimized approach to retrieve information on atmospheric carbonyl sulfide (OCS) above the Jungfraujoch station and change in its abundance since 1995

    Science.gov (United States)

    Lejeune, Bernard; Mahieu, Emmanuel; Vollmer, Martin K.; Reimann, Stefan; Bernath, Peter F.; Boone, Christopher D.; Walker, Kaley A.; Servais, Christian

    2017-01-01

    In this paper, we present an optimized retrieval strategy for carbonyl sulfide (OCS), using Fourier transform infrared (FTIR) solar observations made at the high-altitude Jungfraujoch station in the Swiss Alps. More than 200 lines of the ν3 fundamental band of OCS have been systematically evaluated and we selected 4 microwindows on the basis of objective criteria minimizing the effect of interferences, mainly by solar features, carbon dioxide and water vapor absorption lines, while maximizing the information content. Implementation of this new retrieval strategy provided an extended time series of the OCS abundance spanning the 1995-2015 time period, for the study of the long-term trend and seasonal variation of OCS in the free troposphere and stratosphere. Three distinct periods characterize the evolution of the tropospheric partial columns: a first decreasing period (1995-2002), an intermediate increasing period (2002-2008), and the more recent period (2008-2015) which shows no significant trend. Our FTIR tropospheric and stratospheric time series are compared with new in situ gas chromatography mass spectrometry (GCMS) measurements performed by Empa (Laboratory for Air Pollution/Environmental Technology) at the Jungfraujoch since 2008, and with space-borne solar occultation observations by the ACE-FTS instrument on-board the SCISAT satellite, respectively, and they show good agreement. The OCS signal recorded above Jungfraujoch appears to be closely related to anthropogenic sulfur emissions.

  17. A method for retrieving clouds with satellite infrared radiances using the particle filter

    Science.gov (United States)

    Xu, Dongmei; Auligné, Thomas; Descombes, Gaël; Snyder, Chris

    2016-11-01

    Ensemble-based techniques have been widely utilized in estimating uncertainties in various problems of interest in geophysical applications. A new cloud retrieval method is proposed based on the particle filter (PF) by using ensembles of cloud information in the framework of Gridpoint Statistical Interpolation (GSI) system. The PF cloud retrieval method is compared with the Multivariate Minimum Residual (MMR) method that was previously established and verified. Cloud retrieval experiments involving a variety of cloudy types are conducted with the PF and MMR methods with measurements of infrared radiances on multi-sensors onboard both geostationary and polar satellites, respectively. It is found that the retrieved cloud masks with both methods are consistent with other independent cloud products. MMR is prone to producing ambiguous small-fraction clouds, while PF detects clearer cloud signals, yielding closer heights of cloud top and cloud base to other references. More collections of small-fraction particles are able to effectively estimate the semi-transparent high clouds. It is found that radiances with high spectral resolutions contribute to quantitative cloud top and cloud base retrievals. In addition, a different way of resolving the filtering problem over each model grid is tested to better aggregate the weights with all available sensors considered, which is proven to be less constrained by the ordering of sensors. Compared to the MMR method, the PF method is overall more computationally efficient, and the cost of the model grid-based PF method scales more directly with the number of computing nodes.

  18. Edge-Based Feature Extraction Method and Its Application to Image Retrieval

    Directory of Open Access Journals (Sweden)

    G. Ohashi

    2003-10-01

    Full Text Available We propose a novel feature extraction method for content-bases image retrieval using graphical rough sketches. The proposed method extracts features based on the shape and texture of objects. This edge-based feature extraction method functions by representing the relative positional relationship between edge pixels, and has the advantage of being shift-, scale-, and rotation-invariant. In order to verify its effectiveness, we applied the proposed method to 1,650 images obtained from the Hamamatsu-city Museum of Musical Instruments and 5,500 images obtained from Corel Photo Gallery. The results verified that the proposed method is an effective tool for achieving accurate retrieval.

  19. A Method for Combined Passive-Active Microwave Retrievals of Cloud and Precipitation Profiles.

    Science.gov (United States)

    Olson, William S.; Kummerow, Christian D.; Heymsfield, Gerald M.; Giglio, Louis

    1996-10-01

    Three-dimensional tropical squall-line simulations from the Goddard cumulus ensemble (GCE) model are used as input to radiative computations of upwelling microwave brightness temperatures and radar reflectivities at selected microwave sensor frequencies. These cloud/radiative calculations form the basis of a physical cloud/precipitation profile retrieval method that yields estimates of the expected values of the hydrometeor water contents. Application of the retrieval method to simulated nadir-view observations of the aircraft-borne Advanced Microwave Precipitation Radiometer (AMPR) and NASA ER-2 Doppler radar (EDOP) produce random errors of 23%, 19%, and 53% in instantaneous estimates of integrated precipitating liquid, integrated precipitating ice, and surface rain rate, respectively.On 5 October 1993, during the Convection and Atmospheric Moisture Experiment (CAMEX), the AMPR and EDOP were used to observe convective systems in the vicinity of the Florida peninsula. Although the AMPR data alone could be used to retrieve cloud and precipitation vertical profiles over the ocean, retrievals of high-resolution vertical precipitation structure and profile information over land required the combination of AMPR and EDOP observations.No validation data are available for this study; however, the retrieved precipitation distributions from the convective systems are compatible with limited radar climatologies of such systems, as well as being radiometrically consistent with both the AMPR and EDOP observations. In the future, the retrieval method will be adapted to the passive and active microwave measurements from the Tropical Rainfall Measuring Mission (TRMM) satellite sensors.

  20. Mitigating the effect of noise in the hybrid input-output method of phase retrieval.

    Science.gov (United States)

    Trahan, Russell; Hyland, David

    2013-05-01

    Here a modification to the hybrid input-output (HIO) method of phase retrieval is presented which aides in mitigating the negative effects of low signal-to-noise ratios (SNRs). Various type of interferometers measure diffraction patterns which are used to determine the Fourier transform modulus of an objective. Interferometry often suffers from very low SNRs making phase retrieval difficult because of the sensitivity of most phase retrieval algorithms to local minima. Here we analyze the effect of noise on the HIO method. The result is used as a rationale for the proposed modification to the HIO method. The algorithm presented here introduces a filtering scheme which removes much of the Fourier modulus noise. Examples are shown and the results are compared to the HIO method with and without the proposed modification. Comparisons are also made to other methods of filtering the Fourier modulus noise.

  1. Evaluation of semantic-based information retrieval methods in the autism phenotype domain.

    Science.gov (United States)

    Hassanpour, Saeed; O'Connor, Martin J; Das, Amar K

    2011-01-01

    Biomedical ontologies are increasingly being used to improve information retrieval methods. In this paper, we present a novel information retrieval approach that exploits knowledge specified by the Semantic Web ontology and rule languages OWL and SWRL. We evaluate our approach using an autism ontology that has 156 SWRL rules defining 145 autism phenotypes. Our approach uses a vector space model to correlate how well these phenotypes relate to the publications used to define them. We compare a vector space phenotype representation using class hierarchies with one that extends this method to incorporate additional semantics encoded in SWRL rules. From a PubMed-extracted corpus of 75 articles, we show that average rank of a related paper using the class hierarchy method is 4.6 whereas the average rank using the extended rule-based method is 3.3. Our results indicate that incorporating rule-based definitions in information retrieval methods can improve search for relevant publications.

  2. Wave propagation method as an accurate technique for effective refractive index retrieving

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    2009-01-01

    An effective parameters retrieval method based on the wave propagation simulation is proposed and compared with the standard S-parameter procedure. The method is free from possible mistakes originated by the multiple branching of solutions in the S-parameter procedure and shows high accuracy....... The limitations of the new method are discussed....

  3. Retrieval of Extra-Solar Planetary Spectra Using Evolutionary Computational Methods

    Science.gov (United States)

    Terrile, R. J.; Fink, W.; Huntsberger, T.; Lee, S.; Tisdale, E. R.; Tinetti, G.; von Allmen, P.

    2005-12-01

    The spectral information provided by the next generation of extra-solar planet exploration missions will be averaged over the visible disk and the exposure time. Most probably, the interpretation of the observed spectra will not be unique, but families of solutions will provide equally good explanations of the spectral features (degeneracy). Traditional retrieval techniques developed to study the environments of planets in our solar system are inadequate to analyze disk/time-averaged spectra because they assume homogeneous environments, short observational time scales and search only for solutions belonging to the local domain of the initial conditions. We developed an innovative technique that couples evolutionary computational methods to a 3D model that simulates the spectral response of the planet rotating (Tinetti et al., 2005). We have performed a set of preliminary experiments in retrieving the earthshine spectrum recorded by Woolf et al. (2002): nine weighting parameters were retrieved, corresponding to different surface/cloud types (ocean, forest, grass, ground, tundra, ice, high/medium/low clouds) uniformly distributed over 48 planetary pixels. Two distinct retrieval experiments were run: i) evolution of one large solution population with 1000 individuals and ii) evolution of multiple solution islands with 100 individuals in each island. These two experiments returned over 2700 automatically generated retrievals satisfying the error criterion (fitness) of 10% least squares match to the observed spectra. The spectral retrieval procedure with this reduced set of parameters already resulted in a high quality fit of the earthshine spectrum, in agreement with ground truth. The retrieved solutions were divided into classes of spectral fit using clustering tools, which helped visualize the degeneracy in the set of solutions. As a next step we are repeating the experiment using non-uniformly distributed 9 surface/cloud types in 12 planetary pixels (108 retrieved

  4. Retrieval of Earthshine Spectra Using Evolutionary Computational Methods as Analogs for Extra-Solar Planetary Spectra

    Science.gov (United States)

    Terrile, R. J.; Tinetti, G.; Lee, S.; Fink, W.; Huntsberger, T.; von Allmen, P.; Tisdale, E. R.

    2006-05-01

    The spectral information provided by the next generation of extra-solar planet exploration missions will be averaged over the visible disk and the exposure time. Most probably, the interpretation of the observed spectra will not be unique, but families of solutions will provide equally good explanations of the spectral features (degeneracy). Traditional retrieval techniques developed to study the environments of planets in our solar system are inadequate to analyze disk/time-averaged spectra because they assume homogeneous environments, short observational time scales and search only for solutions belonging to the local domain of the initial conditions. We developed an innovative technique that couples evolutionary computational methods to a 3D model that simulates the spectral response of the planet rotating (Tinetti et al., 2005). We have performed a set of preliminary experiments in retrieving the earthshine spectrum recorded by Woolf et al. (2002): nine weighting parameters were retrieved, corresponding to different surface/cloud types (ocean, forest, grass, ground, tundra, ice, high/medium/low clouds) uniformly distributed over 48 planetary pixels. Two distinct retrieval experiments were run: i) evolution of one large solution population with 1000 individuals and ii) evolution of multiple solution islands with 100 individuals in each island. These two experiments returned over 2700 automatically generated retrievals satisfying the error criterion (fitness) of 10% least squares match to the observed spectra. The spectral retrieval procedure with this reduced set of parameters already resulted in a high quality fit of the earthshine spectrum, in agreement with ground truth. The retrieved solutions were divided into classes of spectral fit using clustering tools, which helped visualize the degeneracy in the set of solutions. We have also repeated the experiment using non-uniformly distributed 3 cloud types over ground- truth surface types in 22 illuminated pixels

  5. A Method for Sea Surface Wind Field Retrieval from SAR Image Mode Data

    Institute of Scientific and Technical Information of China (English)

    SHAO Weizeng; SUN Jian; GUAN Changlong; SUN Zhanfeng

    2014-01-01

    To retrieve wind field from SAR images, the development for surface wind field retrieval from SAR images based on the improvement of new inversion model is present. Geophysical Model Functions (GMFs) have been widely applied for wind field retrieval from SAR images. Among them CMOD4 has a good performance under low and moderate wind conditions. Although CMOD5 is developed recently with a more fundamental basis, it has ambiguity of wind speed and a shape gradient of normalized radar cross section under low wind speed condition. This study proposes a method of wind field retrieval from SAR image by com-bining CMOD5 and CMOD4 Five VV-polarisation RADARSAT2 SAR images are implemented for validation and the retrieval re-sults by a combination method (CMOD5 and CMOD4) together with CMOD4 GMF are compared with QuikSCAT wind data. The root-mean-square error (RMSE) of wind speed is 0.75 m s-1 with correlation coefficient 0.84 using the combination method and the RMSE of wind speed is 1.01 m s-1 with correlation coefficient 0.72 using CMOD4 GMF alone for those cases. The proposed method can be applied to SAR image for avoiding the internal defect in CMOD5 under low wind speed condition.

  6. A novel method of retrieving the polarization qubits after being transmitted in turbid media

    Science.gov (United States)

    Xu, Qiang; Guo, Zhongyi; Tao, Qiangqiang; Jiao, Weiyan; Qu, Shiliang; Gao, Jun

    2015-03-01

    In this paper, we have mainly investigated the reconstruction of the polarization states of the incident light which passed through the turbid atmospheric media. Here, a novel polarization retrieve (PR) method is established using a Monte Carlo simulation algorithm, which is proposed to study the influence of particle scattering. The polarization states of the initial field could be retrieved accurately according to the polarization states of the scattered field and the Mueller matrix. In the case of a single homogeneous medium, the mean error of retrieved polarization is close to zero. We have also applied this method to complex atmospheric environments such as random-sized distribution particles and various index of refraction media. By comparison with the existing polarization maintaining method, the results indicate that the PR method is more applicable to disordered media with relatively larger particles. Moreover, the errors of the retrieved degree of polarization are below 0.11%, and the errors of the retrieved angle of polarization are below 0.54% in our mixed media model. So, this work will be very significant for polarizing quantum secure communication in scattering medium over a long-distance scope.

  7. An Efficient Method for Rare Spectra Retrieval in Astronomical Databases

    CERN Document Server

    Du, Changde; Yang, Haifeng; Hou, Wen; Guo, Yanxin

    2016-01-01

    One of important aims of astronomical data mining is to systematically search for specific rare objects in a massive spectral dataset, given a small fraction of identified samples with the same type. Most existing methods are mainly based on binary classification, which usually suffer from uncompleteness when the known samples are too few. While, rank-based methods would provide good solutions for such case. After investigating several algorithms, a method combining bipartite ranking model with bootstrap aggregating techniques was developed in this paper. The method was applied in searching for carbon stars in the spectral data of Sloan Digital Sky Survey (SDSS) DR10, and compared with several other popular methods used in data mining. Experimental results validate that the proposed method is not only the most effective but also less time consuming among these competitors automatically searching for rare spectra in a large but unlabelled dataset.128

  8. A Method to Retrieve Rainfall Rate over Land from TRMM Observations

    Science.gov (United States)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.

    2002-01-01

    Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) observations over mesoscale convective systems (MCSs) reveal that there are localized maxima in the rain rate with a scale of about 10 to 20 km that represent thunderstorms (Cbs). Some of these Cbs are developing or intense, while others are decaying or weak. These Cbs constitute only about 20 % of the rain area of a given MCS. Outside of Cbs, the average rain rate is much weaker than that within Cbs. From an analysis of the PR data, we find that the spatial distribution of rain and its character, convective or stratiform, is highly inhomogeneous. This complex nature of rain exists on a scale comparable to that of a Cb. The 85 GHz brightness temperature, T85, observations of the TRMM Microwave Imager (TMI) radiometer taken over an MCS reflect closely the PR rain rate pattern over land. Local maxima in rain rate shown by PR are observed as local minima in T85. Where there are no minima in T85, PR observations indicate there is light rain. However, the TMI brightness temperature measurements (Tbs) have poor ability to discriminate convective rain from stratiform rain. For this reason, a TMI rain retrieval procedure that depends primarily on the magnitude of Tbs performs poorly. In order to retrieve rain rate from TMI data on land one has to include the spatial distribution information deduced from the T85 data in the retrieval method. Then, quantitative estimation of rain rate can be accomplished. A TMI rain retrieval method developed along these lines can yield estimates of rain rate and its frequency distribution which agree closely with that given by PR. We find the current TRMM project TMI (Version 5) rain retrieval algorithm on land could be improved with the retrieval scheme developed here. To support the conceptual frame work of the rain retrieval method developed here, a theoretical analysis of the TMI brightness temperatures in convective and stratiform regions is presented.

  9. Texture based feature extraction methods for content based medical image retrieval systems.

    Science.gov (United States)

    Ergen, Burhan; Baykara, Muhammet

    2014-01-01

    The developments of content based image retrieval (CBIR) systems used for image archiving are continued and one of the important research topics. Although some studies have been presented general image achieving, proposed CBIR systems for archiving of medical images are not very efficient. In presented study, it is examined the retrieval efficiency rate of spatial methods used for feature extraction for medical image retrieval systems. The investigated algorithms in this study depend on gray level co-occurrence matrix (GLCM), gray level run length matrix (GLRLM), and Gabor wavelet accepted as spatial methods. In the experiments, the database is built including hundreds of medical images such as brain, lung, sinus, and bone. The results obtained in this study shows that queries based on statistics obtained from GLCM are satisfied. However, it is observed that Gabor Wavelet has been the most effective and accurate method.

  10. Image Retrieval Based on Multiview Constrained Nonnegative Matrix Factorization and Gaussian Mixture Model Spectral Clustering Method

    Directory of Open Access Journals (Sweden)

    Qunyi Xie

    2016-01-01

    Full Text Available Content-based image retrieval has recently become an important research topic and has been widely used for managing images from repertories. In this article, we address an efficient technique, called MNGS, which integrates multiview constrained nonnegative matrix factorization (NMF and Gaussian mixture model- (GMM- based spectral clustering for image retrieval. In the proposed methodology, the multiview NMF scheme provides competitive sparse representations of underlying images through decomposition of a similarity-preserving matrix that is formed by fusing multiple features from different visual aspects. In particular, the proposed method merges manifold constraints into the standard NMF objective function to impose an orthogonality constraint on the basis matrix and satisfy the structure preservation requirement of the coefficient matrix. To manipulate the clustering method on sparse representations, this paper has developed a GMM-based spectral clustering method in which the Gaussian components are regrouped in spectral space, which significantly improves the retrieval effectiveness. In this way, image retrieval of the whole database translates to a nearest-neighbour search in the cluster containing the query image. Simultaneously, this study investigates the proof of convergence of the objective function and the analysis of the computational complexity. Experimental results on three standard image datasets reveal the advantages that can be achieved with the proposed retrieval scheme.

  11. Time-Quality Tradeoff of Waiting Strategies for Tutors to Retrieve Relevant Teaching Methods

    Science.gov (United States)

    Shih, Wen-Chung; Tseng, Shian-Shyong; Yang, Che-Ching; Liang, Tyne

    2011-01-01

    As more and more undergraduate students act as voluntary tutors to rural pupils after school, there is a growing need for a supporting environment to facilitate adaptive instruction. Among others, a teaching method retrieval system is intended to help tutors find relevant teaching methods for teaching a particular concept. However, teaching…

  12. Noise robustness of a combined phase retrieval and reconstruction method for phase-contrast tomography

    DEFF Research Database (Denmark)

    Kongskov, Rasmus Dalgas; Jørgensen, Jakob Sauer; Poulsen, Henning Friis

    2016-01-01

    Classical reconstruction methods for phase-contrast tomography consist of two stages: phase retrieval and tomographic reconstruction. A novel algebraic method combining the two was suggested by Kostenko et al. [Opt. Express 21, 12185 (2013) [CrossRef], and preliminary results demonstrated improved...... is substantially more robust toward noise; our simulations point to a possible reduction in counting times by an order of magnitude....

  13. Direct Method Gas Phase Oxygen Abundances of 4 Lyman Break Analogs

    CERN Document Server

    Brown, Jonathan S; Pogge, Richard W

    2014-01-01

    We measure the gas-phase oxygen abundances in 4 Lyman Break Analogs (LBAs) using auroral emission lines to derive direct abundances. The direct method oxygen abundances of these objects are generally consistent with the empirically-derived strong-line method values, confirming that these objects are low oxygen abundance outliers from the Mass-Metallicity (MZ) relation defined by star forming SDSS galaxies. We find slightly anomalous excitation conditions (Wolf-Rayet features) that could potentially bias the empirical estimates towards high values if caution is not exercised in the selection of the strong-line calibration used. The high rate of star formation and low oxygen abundance of these objects is consistent with the predictions of the Fundamental Metallicity Relation (FMR), in which the infall of relatively unenriched gas simultaneously triggers an episode of star formation and dilutes ISM of the host galaxy.

  14. Spectral modeling of water ice-rich areas on Ceres' surface from Dawn-VIR data analysis: abundance and grain size retrieval

    Science.gov (United States)

    Raponi, Andrea; De Sanctis, Maria Cristina; Ciarniello, Mauro; Tosi, Federico; Combe, Jean-Philippe; Frigeri, Alessandro; Zambon, Francesca; Ammannito, Eleonora; Giacomo Carrozzo, Filippo; Magni, Gianfranco; Capria, Maria Teresa; Formisano, Michelangelo; Longobardo, Andrea; Palomba, Ernesto; Pieters, Carle; Russell, Christopher T.; Raymond, Carol; Dawn/VIR Team

    2016-10-01

    Dawn spacecraft orbits around Ceres since early 2015 acquiring a huge amount of data at different spatial resolutions during the several phases of the mission. VIR, the visible and InfraRed spectrometer onboard Dawn [1] allowed to detect the principal mineralogical phases present on Ceres: a large abundance of dark component, NH4-phillosilicates and carbonates.Water has been detected in small areas on Ceres' surface by the Dawn-VIR instrument. The most obvious finding is located in Oxo crater [2]. Further detections of water have been made during the Survey observation phase (1.1 km/pixel) and High-Altitude Mapping Orbit (400 m/px) [3]. During the LAMO phase (Low Altitude Mapping Orbit), the data with increased spatial resolution (100 m/px) coming from both regions have improved the detection of water, highlighting clear diagnostic water ice absorption features. In this study, we focused on spectral modeling of VIR spectra of Oxo and another crater (lon = 227°, lat 57°), near Messor crater.The Hapke radiative transfer model [4] has been applied in order to retrieve the water ice properties. We consider two types of mixtures: areal and intimate mixing. In areal mixing, the surface is modelled as patches of pure water ice, with each photon scattered within one patch. In intimate mixing, the particles of water ice are in contact with particles of the dark terrain, and both are involved in the scattering of a single photon. The best fit with the measured spectra has been derived with the areal mixture. The water ice abundance obtained is up to 15-20% within the field of view, and the grain size retrieved is of the order of 100-200 μm. Phyllosilicates and carbonates, which are ubiquitous on Ceres surface [5], have been also detected and modeled in correspondence with the icy regions. The water ice is typically located near and within the shadows projected by the crater rims. Further analysis is required to study the thermal state of the ice and its origin

  15. A Three-Dimensional Satellite Retrieval Method for Atmospheric Temperature and Moisture Profiles

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; QIU Chongjian; HUANG Jianping

    2008-01-01

    A three-dimensional variational method iS proposed to simultaneously retrieve the 3-D atmospheric temperature and moisture profiles from satellite radiance measurements.To include both vertical structure and the horizontal patterns of the atmospheric temperature and moisture.an EOF technique iS used to decompose the temperature and moisture field in a 3-D space.A number of numerical simulations are conducted and they demonstrate that the 3-D method iS less sensitive to the observation errors compared to the 1-D method.When the observation error iS more than 2.0 K.to get the best results.the truncation number for the EOF'S expansion have to be restricted to 2 in the 1-D method.while it can be set as large as 40 in a 3-D method.This results in the truncation error being reduced and the retrieval accuracy being improved in the 3-D method.Compared to the 1-D method.the rlTLS errors of the 3-D method are reduced by 48%and 36%for the temperature and moisture retrievals,respectively.Using the real satellite measured brightness temperatures at 0557 UTC 31 July 2002,the temperature and moisture profiles are retrieved over a region(20°-45°N,100°-125°E)and compared with 37 collocated radiosonde observations.The results show that the retrieval accuracy with a 3-D method iS significantly higher than those with the 1-D method.

  16. Homogenization of metamaterials: Parameters retrieval methods and intrinsic problems

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    2010-01-01

    Metamaterials (MTMs) claim a lot of attention worldwide. Description of the MTMs in terms of effective parameters is a simple and useful tool for characterisation of their electromagnetic properties. So a reliable effective parameters restoration method is on demand. In this paper we report about...

  17. Noninvasive method for retrieval of broken dental implant abutment screw

    Directory of Open Access Journals (Sweden)

    Jagadish Reddy Gooty

    2014-01-01

    Full Text Available Dental implants made of titanium for replacement of missing teeth are widely used because of ease of technical procedure and high success rate, but are not free of complications and may fail. Fracturing of the prosthetic screw continues to be a problem in restorative practice and great challenge to remove the fractured screw conservatively. This case report describes and demonstrates the technique of using an ultrasonic scaler in the removal of the fracture screw fragment as a noninvasive method without damaging the hex of implants.

  18. Phase retrieval methods for surface x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Saldin, D.K.; Harder, R.J.; Shneerson, V.L. [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI (United States); Moritz, W. [Institute of Crystallography and Applied Mineralogy, University of Munich, Munich (Germany)

    2001-11-26

    We develop an iterative input-output feedback method for the phasing of surface x-ray diffraction (SXRD) amplitudes that relies on successive operations in real and reciprocal space. We demonstrate its use for the recovery of the real and positive electron density of a surface unit cell from simulated SXRD intensities. We have successfully recovered the entire surface electron density in a case where the two-dimensional surface unit cell is the same as that of the bulk and also in one where the surface unit cell is four times larger than that of the bulk. We show that the exponential modelling algorithm for structure completion derived earlier from maximum entropy theory may be regarded as a special case of an input-output phasing algorithm with a particular form of object-domain operations. (author)

  19. An Exploration of Retrieval-Enhancing Methods for Integrated Search in a Digital Library

    DEFF Research Database (Denmark)

    Sørensen, Diana Ransgaard; Bogers, Toine; Larsen, Birger

    2012-01-01

    different types of documents (bibliographic records for articles and books as well as full-text articles) using the iSearch collection: combining all document types in a single index, weighting the different document types using priors, and using collection fusion techniques to merge the retrieval results...... on three separate indexes corresponding to each of the document types. We find that a properly optimized retrieval model on a single combined index containing all documents without any special treatment performs no worse than our weighting and fusion methods, suggesting that more work is needed...

  20. A Proposed Method of Measuring the Utility of Individual Information Retrieval Tools.

    Science.gov (United States)

    Meadow, Charles T.

    1996-01-01

    Proposes a method of evaluating information retrieval systems by concentrating on individual tools (commands, their menus or graphic interface equivalents, or a move/stratagem). A user would assess the relative success of a small part of a search, and every tool used in that part would be credited with a contribution to the result. Cumulative…

  1. A Novel Method of Case Representation and Retrieval in CBR for E-Learning

    Science.gov (United States)

    Khamparia, Aditya; Pandey, Babita

    2017-01-01

    In this paper we have discussed a novel method which has been developed for representation and retrieval of cases in case based reasoning (CBR) as a part of e-learning system which is based on various student features. In this approach we have integrated Artificial Neural Network (ANN) with Data mining (DM) and CBR. ANN is used to find the…

  2. Clustering Methods; Part IV of Scientific Report No. ISR-18, Information Storage and Retrieval...

    Science.gov (United States)

    Cornell Univ., Ithaca, NY. Dept. of Computer Science.

    Two papers are included as Part Four of this report on Salton's Magical Automatic Retriever of Texts (SMART) project report. The first paper: "A Controlled Single Pass Classification Algorithm with Application to Multilevel Clustering" by D. B. Johnson and J. M. Laferente presents a single pass clustering method which compares favorably…

  3. Methods to retrieve the complex refractive index of aquatic suspended particles: going beyond simple shapes

    Science.gov (United States)

    Sánchez, Albert-Miquel; Piera, Jaume

    2016-07-01

    The scattering properties of aquatic suspended particles have many optical applications. Several data inversion methods have been proposed to estimate important features of particles, such as their size distribution or their refractive index. Most of the proposed methods are based on the Lorenz-Mie theory to solve Maxwell's equations, where particles are considered homogeneous spheres. A generalization that allows consideration of more complex-shaped particles is the T-matrix method. Although this approach imposes some geometrical restrictions (particles must be rotationally symmetrical) it is applicable to many life forms of phytoplankton. In this paper, three different scenarios are considered in order to compare the performance of several inversion methods for retrieving refractive indices. The error associated with each method is discussed and analyzed. The results suggest that inverse methods using the T-matrix approach are useful to accurately retrieve the refractive indices of particles with complex shapes, such as for many phytoplankton organisms.

  4. An overview of the design and methods for retrieving high-quality studies for clinical care

    Directory of Open Access Journals (Sweden)

    Haynes R Brian

    2005-06-01

    Full Text Available Abstract Background With the information explosion, the retrieval of the best clinical evidence from large, general purpose, bibliographic databases such as MEDLINE can be difficult. Both researchers conducting systematic reviews and clinicians faced with a patient care question are confronted with the daunting task of searching for the best medical literature in electronic databases. Many have advocated the use of search filters or "hedges" to assist with the searching process. The purpose of this report is to describe the design and methods of a study that set out to develop optimal search strategies for retrieving sound clinical studies of health disorders in large electronics databases. Objective To describe the design and methods of a study that set out to develop optimal search strategies for retrieving sound clinical studies of health disorders in large electronic databases. Design An analytic survey comparing hand searches of 170 journals in the year 2000 with retrievals from MEDLINE, EMBASE, CINAHL, and PsycINFO for candidate search terms and combinations. The sensitivity, specificity, precision, and accuracy of unique search terms and combinations of search terms were calculated. Conclusion A study design modeled after a diagnostic testing procedure with a gold standard (the hand search of the literature and a test (the search terms is an effective way of developing, testing, and validating search strategies for use in large electronic databases.

  5. Image Retrieval and Classification Method Based on Euclidian Distance Between Normalized Features Including Wavelet Descriptor

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2013-10-01

    Full Text Available Image retrieval method based on Euclidian distance between normalized features with their mean and variance in feature space is proposed. Effectiveness of the normalization is evaluated together with a validation of the proposed image retrieval method. The proposed method is applied for discrimination and identifying dangerous red tide species based on wavelet utilized classification methods together with texture and color features. Through experiments, it is found that classification performance with the proposed wavelet derived shape information extracted from the microscopic view of the phytoplankton is effective for identifying dangerous red tide species among the other red tide species rather than the other conventional texture, color information. Moreover, it is also found that the proposed normalization of features is effective to improve identification performance.

  6. Application of information-retrieval methods to the classification of physical data

    Science.gov (United States)

    Mamotko, Z. N.; Khorolskaya, S. K.; Shatrovskiy, L. I.

    1975-01-01

    Scientific data received from satellites are characterized as a multi-dimensional time series, whose terms are vector functions of a vector of measurement conditions. Information retrieval methods are used to construct lower dimensional samples on the basis of the condition vector, in order to obtain these data and to construct partial relations. The methods are applied to the joint Soviet-French Arkad project.

  7. Monte Carlo Method for Calculating Oxygen Abundances and Their Uncertainties from Strong-Line Flux Measurements

    CERN Document Server

    Bianco, Federica B; Oh, Seung Man; Fierroz, David; Liu, Yuqian; Kewley, Lisa; Graur, Or

    2015-01-01

    We present the open-source Python code pyMCZ that determines oxygen abundance and its distribution from strong emission lines in the standard metallicity scales, based on the original IDL code of Kewley & Dopita (2002) with updates from Kewley & Ellison (2008), and expanded to include more recently developed scales. The standard strong-line diagnostics have been used to estimate the oxygen abundance in the interstellar medium through various emission line ratios in many areas of astrophysics, including galaxy evolution and supernova host galaxy studies. We introduce a Python implementation of these methods that, through Monte Carlo (MC) sampling, better characterizes the statistical reddening-corrected oxygen abundance confidence region. Given line flux measurements and their uncertainties, our code produces synthetic distributions for the oxygen abundance in up to 13 metallicity scales simultaneously, as well as for E(B-V), and estimates their median values and their 66% confidence regions. In additi...

  8. Fresnel phase retrieval method using an annular lens array on an SLM

    Science.gov (United States)

    Loriot, V.; Mendoza-Yero, O.; Pérez-Vizcaíno, J.; Mínguez-Vega, G.; de Nalda, R.; Bañares, L.; Lancis, J.

    2014-10-01

    Wavefront aberrations play a major role when focusing an ultrashort laser pulse to a high-quality focal spot. Here, we report a novel method to measure and correct wavefront aberrations of a 30-fs pulsed laser beam. The method only requires a programmable liquid-crystal spatial light modulator and a camera. Wavefront retrieval is based on pupil segmentation with an annular lens array, which allows us to determine the local phase that minimizes focusing errors due to wavefront aberrations. Our method provides accurate results even when implemented with low dynamic range cameras and polychromatic beams. Finally, the retrieved phase is added to a diffractive lens codified onto the spatial light modulator to experimentally demonstrate near-diffraction-limited femtosecond beam focusing without refractive components.

  9. A New Indexing Method Based on Word Proximity for Chinese Text Retrieval

    Institute of Scientific and Technical Information of China (English)

    DU Lin; SUN Yufang

    2000-01-01

    This paper proposed a novel text representation and matching scheme for Chinese text retrieval. At present, the indexing methods of Chinese retrieval systems are either character-based or word-based. The character-based indexing methods, such as bi-gram or tri-gram indexing, have high false drops due to the mismatches between queries and documents. On the other hand, it's difficult to efficiently identify all the proper nouns, terminology of different domains, and phrases in the word-based indexing systems. The new indexing method uses both proximity and mutual information of the word pairs to represent the text content so as to overcome the high false drop, new word and phrase problems that exist in the character-based and word-based systems. The evaluation results indicate that the average query precision of proximity-based indexing is 5.2% higher than the best results of TREC-5.

  10. Content-Based Image Retrieval Method using the Relative Location of Multiple ROIs

    Directory of Open Access Journals (Sweden)

    LEE, J.

    2011-08-01

    Full Text Available Recently the method of specifying multiple regions of interest (ROI based image retrieval has been suggested. However it measures the similarity of the images without proper consideration of the spatial layouts of the ROIs and thus fails to accurately reflect the intent of the user. In this paper, we propose a new similarity measurement using the relative layouts of the ROIs. The proposed method divides images into blocks of certain size and extracted MPEG-7 dominant colors from the blocks overlapping with the user-designated ROIs to measure their similarities with the target images. At this point, similarity was weighted when the relative location of the ROIs in the query image and the target image was the same. The relative location was calculated by four directions (i.e. up, down, left and right of the basis ROI. The proposed method by an experiment using MPEG-7 XM shows that its performance is higher than the global image retrieval method or the retrieval method that does not consider the relative location of ROIs.

  11. System and method for phase retrieval for radio telescope and antenna control

    Science.gov (United States)

    Dean, Bruce H. (Inventor)

    2013-01-01

    Disclosed herein are systems, methods, and non-transitory computer-readable storage media for radio phase retrieval. A system practicing the method gathers first data from radio waves associated with an object observed via a first aperture, gathers second data from radio waves associated with the object observed via an introduced second aperture associated with the first aperture, generates reduced noise data by incoherently subtracting the second data from the first data, and performs phase retrieval for the radio waves by modeling the reduced noise data using a single Fourier transform. The first and second apertures are at different positions, such as side by side. This approach can include determining a value Q which represents a ratio of wavelength times a focal ratio divided by pixel spacing. This information can be used to accurately measure and correct alignment errors or other optical system flaws in the apertures.

  12. A high spatial resolution retrieval of NO 2 column densities from OMI: method and evaluation

    Directory of Open Access Journals (Sweden)

    R. C. Cohen

    2011-08-01

    Full Text Available We present a new retrieval of tropospheric NO2 vertical column density from the Ozone Monitoring Instrument (OMI based on high spatial and temporal resolution terrain and profile inputs. We compare our NO2 product, the Berkeley High-Resolution (BEHR product, with operational retrievals and find that the operational retrievals are biased high (30 % over remote areas and biased low (8 % over urban regions. Additionally, we find non-negligible impacts on the retrieved NO2 column for terrain pressure (±20 %, albedo (±40 %, and NO2 vertical profile (−75 %–+10 %. We validate the operational and BEHR products using boundary layer aircraft observations from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS-CA field campaign which occurred in June 2008 in California. Results indicate that columns derived using our boundary layer extrapolation method show good agreement with satellite observations (R2 = 0.65–0.83; N = 68 and provide a more robust validation of satellite-observed NO2 column than those determined using full vertical spirals (R2 = 0.26; N = 5 as in previous work. Agreement between aircraft observations and the BEHR product (R2 = 0.83 is better than agreement with the operational products (R2 = 0.65–0.72. We also show that agreement between satellite and aircraft observations can be further improved (e.g. BEHR: R2 = 0.91 using cloud information from the Moderate Resolution Imaging Spectroradiometer (MODIS instrument instead of the OMI cloud product. These results indicate that much of the variance in the operational products can be attributed to coarse resolution terrain pressure, albedo, and profile parameters implemented in the retrievals.

  13. Asymmetrical stripline based method for retrieving the electromagnetic properties of metamaterials

    OpenAIRE

    2013-01-01

    International audience; An experimental characterization technique for determining the electromagnetic properties of metamaterials in the microwave frequency band is presented. The method consists in measuring the S-parameters of an asymmetrical stripline partially filled with the sample to be characterized. For retrieving the characteristic parameters, two different approaches based on quasi-static approximations are compared. This measurement cell allows an "in situ" characterization becaus...

  14. Vibration-resistant phase retrieval method with contrast compensation for phase-shifting interferometry

    Science.gov (United States)

    Liu, Qian; He, Huabin; Yuan, Daocheng; He, Jianguo; Ji, Fang

    2017-04-01

    Vibration hinders the application of phase-shifting interferometry (PSI) to on-machine test and large-aperture mirror measurement. The investigation of PSI fringe disturbed by vibration indicates that, besides tilt-shifting error, inter- and intra-frame contrast variation is significant. The contrast variation is another dominant error source in phase retrieval of PSI. An inter- and intra-frame contrast compensation method is proposed here to retrieve wavefront phase from interferograms subjected to vibration. The method constructs algebraic equations with interferogram data and solves equations using iterative procedures. Experiments validate its effectiveness and manifest its capability to suppress vibration-induced error over a large frequency region. To enhance the calculation efficiency, a spatial subsampling strategy is proposed. Practical testing shows that subsampling reduces calculation time exponentially and preserves retrieval accuracy and spatial resolution. The proposed method, of which the unique ability is compensating the tilt-shifting error and fringe blur caused by vibration, predicates an effective and low-cost solution for PSI applied in vibration.

  15. A New Optical Surface Measurement Method with Iterative Sparsity-Constrained Threshold Phase Retrieval Algorithm

    Directory of Open Access Journals (Sweden)

    Yi Niu

    2014-01-01

    Full Text Available Due to its low complexity and acceptable accuracy, phase retrieval technique has been proposed as an alternative to solve the classic optical surface measurement task. However, to capture the overall wave field, phase retrieval based optical surface measurement (PROSM system has to moderate the CCD position during the multiple-sampling procedure. The mechanical modules of CCD movement may bring about unexpectable deviation to the final results. To overcome this drawback, we propose a new PROSM method based on spatial light modulator (SLM. The mechanical CCD movement can be replaced by an electrical moderation of SLM patterns; thus the deviation can be significantly suppressed in the new PROSM method. In addition, to further improve the performance, we propose a new iterative threshold phase retrieval algorithm with sparsity-constraint to effectively reconstruct the phase of wave field. Experimental results show that the new method provides a more simple and robust solution for the optical surface measurement than the traditional techniques and achieves higher accuracy.

  16. Distributed data organization and parallel data retrieval methods for huge laser scanner point clouds

    Science.gov (United States)

    Hongchao, Ma; Wang, Zongyue

    2011-02-01

    This paper proposes a novel method for distributed data organization and parallel data retrieval from huge volume point clouds generated by airborne Light Detection and Ranging (LiDAR) technology under a cluster computing environment, in order to allow fast analysis, processing, and visualization of the point clouds within a given area. The proposed method is suitable for both grid and quadtree data structures. As for distribution strategy, cross distribution of the dataset would be more efficient than serial distribution in terms of non-redundant datasets, since a dataset is more uniformly distributed in the former arrangement. However, redundant datasets are necessary in order to meet the frequent need of input and output operations in multi-client scenarios: the first copy would be distributed by a cross distribution strategy while the second (and later) would be distributed by an iterated exchanging distribution strategy. Such a distribution strategy would distribute datasets more uniformly to each data server. In data retrieval, a greedy algorithm is used to allocate the query task to a data server, where the computing load is lightest if the data block needing to be retrieved is stored among multiple data servers. Experiments show that the method proposed in this paper can satisfy the demands of frequent and fast data query.

  17. Direct Method Gas-phase Oxygen Abundances of Four Lyman Break Analogs

    Science.gov (United States)

    Brown, Jonathan S.; Croxall, Kevin V.; Pogge, Richard W.

    2014-09-01

    We measure the gas-phase oxygen abundances in four Lyman break analogs using auroral emission lines to derive direct abundances. The direct method oxygen abundances of these objects are generally consistent with the empirically derived strong-line method values, confirming that these objects are low oxygen abundance outliers from the mass-metallicity (MZ) relation defined by star forming Sloan Digital Sky Survey galaxies. We find slightly anomalous excitation conditions (Wolf-Rayet features) that could potentially bias the empirical estimates toward high values if caution is not exercised in the selection of the strong-line calibration. The high rate of star formation and low oxygen abundance of these objects is consistent with the predictions of the fundamental metallicity relation, in which the infall of relatively unenriched gas simultaneously triggers an episode of star formation and dilutes the interstellar medium of the host galaxy. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are the University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; the Ohio State University, and the Research Corporation, on behalf of the University of Notre Dame, University of Minnesota, and University of Virginia.

  18. The Mnemonic Keyword Method: The Effects of Bidirectional Retrieval Training and of Ability to Image on Foreign Language Vocabulary Recall

    Science.gov (United States)

    Wyra, Mirella; Lawson, Michael J.; Hungi, Njora

    2007-01-01

    The mnemonic keyword method is an effective technique for vocabulary acquisition. This study examines the effects on recall of word-meaning pairs of (a) training in use of the keyword procedure at the time of retrieval; and (b) the influence of the self-rated ability to image. The performance of students trained in bidirectional retrieval using…

  19. The (′/-Expansion Method for Abundant Traveling Wave Solutions of Caudrey-Dodd-Gibbon Equation

    Directory of Open Access Journals (Sweden)

    Hasibun Naher

    2011-01-01

    Full Text Available We construct the traveling wave solutions of the fifth-order Caudrey-Dodd-Gibbon (CDG equation by the (/-expansion method. Abundant traveling wave solutions with arbitrary parameters are successfully obtained by this method and the wave solutions are expressed in terms of the hyperbolic, the trigonometric, and the rational functions. It is shown that the (/-expansion method is a powerful and concise mathematical tool for solving nonlinear partial differential equations.

  20. Development and assessment of analysis methods for MATMOS trace gas retrievals

    Science.gov (United States)

    Olsen, K. S.; Toon, G. C.; Boone, C.; Strong, K.

    2011-12-01

    The Mars Atmospheric Trace Molecule Occultation Spectrometer (MATMOS) mission will deploy a high-resolution infrared Fourier transform spectrometer (FTS) to Mars on-board the ExoMars Trace Gas Orbiter in 2016. MATMOS is a joint investigation between the California Institute of Technology, NASA's Jet Propulsion Laboratory, and the Canadian Space Agency (CSA). The instrument will be similar to, and derives a strong heritage from, the CSA's Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) on-board SCISAT. Both MATMOS and ACE-FTS measure the absorption spectra of the atmosphere during solar occultation, making up to 30 measurements per day, one at each satellite sunrise and sunset.ACE-FTS analyzes CO2 to determine temperature and pressure as functions of altitude, then simultaneously retrieves vertical profiles of volume mixing ratio (VMR) for more than two dozen gases using least squares minimization. MATMOS will make use of the GGG analysis suite developed for the MkIV balloon flights, the Atmospheric Trace Molecule Spectroscopy experiment and the ground-based Total Carbon Column Observatory Network. Both retrieval methods divide the spectra into smaller spectral windows and use a Voigt instrument line shape. Their forward models are similar and divide the atmosphere into layers that are assumed to have constant temperature, pressure, and VMR for each molecule. GGG uses the inverse method and its own nonlinear least-squares fitting program to derive partial columns along the optical slant path and to retrieve VMR profiles. MATMOS will inventory the composition of the Martian atmosphere with a sensitivity 2-3 orders of magnitude better than any previous instrument. In order to prepare the GGG analysis suite for the upcoming MATMOS mission, 25 ACE occultations have been analyzed using GGG and compared to the ACE-FTS v3.0 retrievals. This work examines the differences between the two algorithms, identifies those that produce inconsistencies

  1. Linking landscape characteristics to local grizzly bear abundance using multiple detection methods in a hierarchical model

    Science.gov (United States)

    Graves, T.A.; Kendall, K.C.; Royle, J. Andrew; Stetz, J.B.; Macleod, A.C.

    2011-01-01

    Few studies link habitat to grizzly bear Ursus arctos abundance and these have not accounted for the variation in detection or spatial autocorrelation. We collected and genotyped bear hair in and around Glacier National Park in northwestern Montana during the summer of 2000. We developed a hierarchical Markov chain Monte Carlo model that extends the existing occupancy and count models by accounting for (1) spatially explicit variables that we hypothesized might influence abundance; (2) separate sub-models of detection probability for two distinct sampling methods (hair traps and rub trees) targeting different segments of the population; (3) covariates to explain variation in each sub-model of detection; (4) a conditional autoregressive term to account for spatial autocorrelation; (5) weights to identify most important variables. Road density and per cent mesic habitat best explained variation in female grizzly bear abundance; spatial autocorrelation was not supported. More female bears were predicted in places with lower road density and with more mesic habitat. Detection rates of females increased with rub tree sampling effort. Road density best explained variation in male grizzly bear abundance and spatial autocorrelation was supported. More male bears were predicted in areas of low road density. Detection rates of males increased with rub tree and hair trap sampling effort and decreased over the sampling period. We provide a new method to (1) incorporate multiple detection methods into hierarchical models of abundance; (2) determine whether spatial autocorrelation should be included in final models. Our results suggest that the influence of landscape variables is consistent between habitat selection and abundance in this system. ?? 2011 The Authors. Animal Conservation ?? 2011 The Zoological Society of London.

  2. A comparison of dimensionality reduction methods for retrieval of similar objects in simulation data

    Energy Technology Data Exchange (ETDEWEB)

    Cantu-Paz, E; Cheung, S S; Kamath, C

    2003-09-23

    High-resolution computer simulations produce large volumes of data. As a first step in the analysis of these data, supervised machine learning techniques can be used to retrieve objects similar to a query that the user finds interesting. These objects may be characterized by a large number of features, some of which may be redundant or irrelevant to the similarity retrieval problem. This paper presents a comparison of six dimensionality reduction algorithms on data from a fluid mixing simulation. The objective is to identify methods that efficiently find feature subsets that result in high accuracy rates. Our experimental results with single- and multi-resolution data suggest that standard forward feature selection produces the smallest feature subsets in the shortest time.

  3. A Novel Bias Correction Method for Soil Moisture and Ocean Salinity (SMOS Soil Moisture: Retrieval Ensembles

    Directory of Open Access Journals (Sweden)

    Ju Hyoung Lee

    2015-12-01

    Full Text Available Bias correction is a very important pre-processing step in satellite data assimilation analysis, as data assimilation itself cannot circumvent satellite biases. We introduce a retrieval algorithm-specific and spatially heterogeneous Instantaneous Field of View (IFOV bias correction method for Soil Moisture and Ocean Salinity (SMOS soil moisture. To the best of our knowledge, this is the first paper to present the probabilistic presentation of SMOS soil moisture using retrieval ensembles. We illustrate that retrieval ensembles effectively mitigated the overestimation problem of SMOS soil moisture arising from brightness temperature errors over West Africa in a computationally efficient way (ensemble size: 12, no time-integration. In contrast, the existing method of Cumulative Distribution Function (CDF matching considerably increased the SMOS biases, due to the limitations of relying on the imperfect reference data. From the validation at two semi-arid sites, Benin (moderately wet and vegetated area and Niger (dry and sandy bare soils, it was shown that the SMOS errors arising from rain and vegetation attenuation were appropriately corrected by ensemble approaches. In Benin, the Root Mean Square Errors (RMSEs decreased from 0.1248 m3/m3 for CDF matching to 0.0678 m3/m3 for the proposed ensemble approach. In Niger, the RMSEs decreased from 0.14 m3/m3 for CDF matching to 0.045 m3/m3 for the ensemble approach.

  4. Proposal of a non-lethal visual census method to estimate freshwater stingray abundance

    Directory of Open Access Journals (Sweden)

    Mónica Andrea Morales-Betancourt

    2016-01-01

    Full Text Available There is not a current method to estimate South American freshwater stingray’s abundance. Therefore we designed a census method and tested it in the field. It consists of making nocturnal surveys by boat in large rivers (>25m width and floodplain lagoons of varying sizes, along transects of 100m x 10m (1000 m2. We applied this method in the Tomo River, a tributary of the Orinoco River in Colombia. 110 transects were surveyed in 200 runs. A total of 149 rays of four species were recorded: Potamotrygon motoro, Potamotrygon orbignyi, Potamotrygon schroederi and Paratrygon aiereba. P. motoro was the most abundant with a density of 0.31 individuals /1000 m2 (SD=0.5. This method gave optimal results when applied to habitats with high transparency and shallow depth (< 1m since it permitted the identification of both adults and juveniles present.

  5. Temporally modulated phase retrieval method for weak temporal phase measurement of laser pulses

    CERN Document Server

    Qiao, Zhi; Wang, Xiaochao; Jing, Yuanyuan; Fan, Wei; Lin, Zunqi

    2016-01-01

    The measurement of weak temporal phase for picosecond and nanosecond laser pulses is important but quite difficult. We propose a simple iterative algorithm, which is based on a temporally movable phase modulation process, to retrieve the weak temporal phase of laser pulses. This unambiguous method can achieve a high accuracy and simultaneously measure the weak temporal phase and temporal profile of pulses, which are almost transform-limited. Detailed analysis shows that this iterative method has valuable potential applications in the characterization of pulses with weak temporal phase.

  6. Note: Phase retrieval method for analyzing single-phase displacement interferometry data

    Energy Technology Data Exchange (ETDEWEB)

    Chen, X. H.; Zeng, X. L.; Fan, D.; Liu, Q. C.; Bie, B. X.; Zhou, X. M., E-mail: xzhou@pims.ac.cn; Luo, S. N., E-mail: sluo@pims.ac.cn [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610207 (China)

    2014-02-15

    We present a phase retrieval method (PRM) for analyzing single-phase displacement interferometry measurements on rapidly changing velocity histories, including photon Doppler velocimetry (PDV). PRM identifies the peaks and valleys as well as zero-crossing points in a PDV time series, performs normalization and extracts point-by-point phase and thus velocity information. PRM does not require a wide time window as in sliding window Fourier transformation, and thus improves the effective temporal resolution. This method is implemented in analyzing PDV data obtained from gas gun experiments, and validated against simultaneous measurements with velocity interferometer system for any reflector.

  7. Indirect methods of retrieval of important mesospheric gas constituents from available measurements data

    Science.gov (United States)

    Kulikov, Mikhail; Nechaev, Anton; Belikovich, Mikhail; Ermakova, Tatiana; Feigin, Alexander

    2016-04-01

    Observation of minor gas constituents is traditionally considered as one of the fundamental problems in investigations of the Earth's mesosphere and mesopause region. Since direct and regular measurements are still rather scanty, indirect methods are a useful tool. Based on a priori assumptions about possible relationships between measured and retrieved characteristics (for example, photochemical models), they allow one to obtain additional information about the important constituents from available experimental data. In this presentation we discuss, firstly, the restrictions on the use of the ozone steady state equilibrium condition for the retrieval of atomic oxygen and hydrogen concentrations from O2 and OH airglow emissions ratios and O3 concentration measurements. Secondly, we present a statistical Bayesian procedure of retrieving the concentrations of important constituents in mesosphere from available satellite and ground based experimental data. The technique is based on the application of the so-called basic dynamic model of mesospheric photochemistry, which is simplified mathematically correctly in a special manner and describes the most significant reactions between components of the families of odd hydrogen and oxygen. The work was supported by the Russian Science Foundation (Contract No. 15-17-10024).

  8. A high spatial resolution retrieval of NO2 column densities from OMI: method and evaluation

    Directory of Open Access Journals (Sweden)

    R. C. Cohen

    2011-04-01

    Full Text Available We present a new retrieval of tropospheric NO2 vertical column density from the Ozone Monitoring Instrument (OMI based on high spatial and temporal resolution terrain and profile inputs. We find non-negligible impacts on the retrieved NO2 column for terrain pressure (±20%, albedo (±40%, and NO2 vertical profile (−75%–+10%. We compare our NO2 product, the Berkeley High-Resolution (BEHR product, with operational retrievals and find that the operational retrievals are biased high (30% over remote areas and biased low (8% over urban regions. We validate the operational and BEHR products using boundary layer aircraft observations from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS-CA field campaign which occurred in June 2008 in California. Results indicate that columns derived using our boundary layer extrapolation method show good agreement with satellite observations (R2 = 0.65–0.83; N = 68 and provide a more robust validation of satellite-observed NO2 column than those determined using full vertical spirals (R2 = 0.26; N = 5 as in previous work. Agreement between aircraft observations and the BEHR product (R2 = 0.83 is better than agreement with the operational products (R2 = 0.65–0.72. We also show that agreement between satellite and aircraft observations for all products can be further improved (e.g. BEHR: R2 = 0.91 using cloud information from the Moderate Resolution Imaging Spectroradiometer (MODIS instrument instead of the OMI cloud product. These results indicate that much of the variance in the operational products can be attributed to coarse resolution terrain and profile parameters.

  9. A novel Bayesian DNA motif comparison method for clustering and retrieval.

    Directory of Open Access Journals (Sweden)

    Naomi Habib

    2008-02-01

    Full Text Available Characterizing the DNA-binding specificities of transcription factors is a key problem in computational biology that has been addressed by multiple algorithms. These usually take as input sequences that are putatively bound by the same factor and output one or more DNA motifs. A common practice is to apply several such algorithms simultaneously to improve coverage at the price of redundancy. In interpreting such results, two tasks are crucial: clustering of redundant motifs, and attributing the motifs to transcription factors by retrieval of similar motifs from previously characterized motif libraries. Both tasks inherently involve motif comparison. Here we present a novel method for comparing and merging motifs, based on Bayesian probabilistic principles. This method takes into account both the similarity in positional nucleotide distributions of the two motifs and their dissimilarity to the background distribution. We demonstrate the use of the new comparison method as a basis for motif clustering and retrieval procedures, and compare it to several commonly used alternatives. Our results show that the new method outperforms other available methods in accuracy and sensitivity. We incorporated the resulting motif clustering and retrieval procedures in a large-scale automated pipeline for analyzing DNA motifs. This pipeline integrates the results of various DNA motif discovery algorithms and automatically merges redundant motifs from multiple training sets into a coherent annotated library of motifs. Application of this pipeline to recent genome-wide transcription factor location data in S. cerevisiae successfully identified DNA motifs in a manner that is as good as semi-automated analysis reported in the literature. Moreover, we show how this analysis elucidates the mechanisms of condition-specific preferences of transcription factors.

  10. A Systematic Retrieval Analysis of Secondary Eclipse Spectra I: A Comparison of Atmospheric Retrieval Techniques

    CERN Document Server

    Line, Michael R; Zhang, Xi; Knutson, Heather; Kammer, Joshua; Ellison, Elias; Deroo, Pieter; Crisp, Dave; Yung, Yuk

    2013-01-01

    Spectra of exoplanet atmospheres provide us the opportunity to improve our understanding of these objects just as remote sensing in our own solar system has increased our understanding of the solar system bodies. The challenge is to quantitatively determine the range of temperatures and species abundances allowed by the data. This challenge is often difficult given the low information content of most exoplanet spectra which commonly leads to degeneracies in the interpretation. A variety of temperature and abundance retrieval approaches have been applied to exoplanet spectra, but no previous investigations have sought to compare these approaches. In this investigation we compare three different retrieval methods: Optimal Estimation, Differential Evolution Markov Chain Monte Carlo, and Bootstrap Monte Carlo. We call our suite of retrieval algorithms the Caltech Inverse Modeling and Retrieval Algorithms (CHIMERA). We discuss what we can expect in terms of uncertainties in abundances and temperatures given curren...

  11. Levenberg-Marquardt method with simultaneous calculations of averaging kernels and errors for methane retrieval from IASI spectra

    Science.gov (United States)

    Khamatnurova, M. Y.; Gribanov, K. G.

    2015-11-01

    Levenberg-Marquardt method parameter selection for methane vertical profile retrieval from IASI/METOP spectra is presented. A modified technique for iterative calculation of averaging kernels and a posteriori errors for every spectrum is suggested. Known from literature method is expanded for the case of absence of a priori statistics for methane vertical profiles. Software for massive processing of IASI spectra using is developed. Effect of LM parameter selection on averaging kernel norm and a posteriori errors is illustrated. NCEP reanalysis data provided by ESRL (NOAA, Boulder, USA) were taken as initial guess. Surface temperature, temperature and humidity vertical profiles are retrieved before methane vertical profile retrieval.

  12. PEOPLE RETRIEVAL BY MEANS OF COMPOSITE PICTURES: METHODS, SYSTEMS AND PRACTICAL DECISIONS

    Directory of Open Access Journals (Sweden)

    G. A. Kukharev

    2015-07-01

    Full Text Available We discuss the problem of people retrieval by means of composite pictures and methods of its practical realization. Earlier on, the problem was posed in the previous paper by the authors, and this paper deals with its further development. The starting premise here is that for the successful search of people by their sketches it is necessary to transform these sketches into sets of populations of sketches imitating evidence of «group of witnesses» and evidence with incomplete information in verbal portraits. Variants of structures for benchmark «photo-sketch» databases are presented, intended for modeling and practical realization of original photos retrieval by sketches, which new component is a population of sketches. Problems of preprocessing for initial sketches and original photos and its influence on the result of their comparison are discussed. Simple sketch recognition systems (Simple FaRetSys and a problem of original photos retrieval by the sketches are considered. Shortcomings of such systems are shown and new decisions on extending and development of simple systems (Extended FaRetSys are presented. Experiments on searching of original photos by sketches in the CUFS database of sketches and similar experiments on widely known FERET and CUFSF facial databases are presented. Three frameworks are offered for retrieval performance improvement. In the first one, original sketches are transformed into populations, and then in these populations the sketch similar to the given sketch (Forensic Sketch is already defined. The class of the sketch found in a population «by definition» unambiguously corresponds to a class of the original photo. In the second framework, the Forensic Sketch is transformed to a population of sketches, and all original sketches in a benchmarking database are compared to sketches from populations of the Forensic Sketch. The class of matches is determined in the same manner as in the first framework. The third

  13. Monte Carlo method for calculating oxygen abundances and their uncertainties from strong-line flux measurements

    Science.gov (United States)

    Bianco, F. B.; Modjaz, M.; Oh, S. M.; Fierroz, D.; Liu, Y. Q.; Kewley, L.; Graur, O.

    2016-07-01

    We present the open-source Python code pyMCZ that determines oxygen abundance and its distribution from strong emission lines in the standard metallicity calibrators, based on the original IDL code of Kewley and Dopita (2002) with updates from Kewley and Ellison (2008), and expanded to include more recently developed calibrators. The standard strong-line diagnostics have been used to estimate the oxygen abundance in the interstellar medium through various emission line ratios (referred to as indicators) in many areas of astrophysics, including galaxy evolution and supernova host galaxy studies. We introduce a Python implementation of these methods that, through Monte Carlo sampling, better characterizes the statistical oxygen abundance confidence region including the effect due to the propagation of observational uncertainties. These uncertainties are likely to dominate the error budget in the case of distant galaxies, hosts of cosmic explosions. Given line flux measurements and their uncertainties, our code produces synthetic distributions for the oxygen abundance in up to 15 metallicity calibrators simultaneously, as well as for E(B- V) , and estimates their median values and their 68% confidence regions. We provide the option of outputting the full Monte Carlo distributions, and their Kernel Density estimates. We test our code on emission line measurements from a sample of nearby supernova host galaxies (z github.com/nyusngroup/pyMCZ.

  14. A Simple Method to Determine if a Music Information Retrieval System is a "Horse"

    DEFF Research Database (Denmark)

    Sturm, Bob L.

    2014-01-01

    . Akin to the controlled experiments designed to test the intellect of the famous horse ``Clever Hans'', we perform two experiments to show how three state-of-the-art music genre recognition (MGR) and music emotion recognition (MER) systems are relying on factors confounded with the ``ground truth......We propose and demonstrate a simple method to determine if a music information retrieval (MIR) system is using factors irrelevant to the task for which it is designed. This is of critical importance to certain use cases, but cannot be accomplished using standard approaches to evaluation in MIR...

  15. Performance of Ruecking's Word-compression Method When Applied to Machine Retrieval from a Library Catalog

    Directory of Open Access Journals (Sweden)

    Ben-Ami Lipetz

    1969-12-01

    Full Text Available F. H. Ruecking's word-compression algorithm for retrieval of bibliographic data from computer stores was tested for performance in matching user-supplied, unedited bibliographic data to the bibliographic data contained in a library catalog. The algorithm was tested by manual simulation, using data derived from 126 case studies of successful manual searches of the card catalog at Sterling Memorial Library, Yale University. The algorithm achieved 70% recall in comparison to conventional searching. Its accepta- bility as a substitute for conventional catalog searching methods is ques- tioned unless recall performance can be improved, either by use of the algorithm alone or in combination with other algorithms.

  16. Comparison of two split-window methods for retrieving land surface temperature from MODIS data

    Indian Academy of Sciences (India)

    Shaohua Zhao; Qiming Qin; Yonghui Yang; Yujiu Xiong; Guoyu Qiu

    2009-08-01

    Land surface temperature (LST) is a key parameter in environment and earth science study, especially for monitoring drought. The objective of this work is a comparison of two split-window methods: Mao method and Sobrino method, for retrieving LST using MODIS (Moderate-resolution Imaging Spectroradiometer) data in North China Plain. The results show that the max, min and mean errors of Mao method are 1.33K, 1.54K and 0.13K lower than the standard LST product respectively; while those of Sobrino method are 0.73K, 1.46K and 1.50K higher than the standard respectively. Validation of the two methods using LST product based on weather stations shows a good agreement between the standard and Sobrino method, with RMSE of 1.17K, whereas RMSE of Mao method is 1.85K. Finally, the study introduces the Sobmao method, which is based on Sobrino method but simplifies the estimation of atmospheric water vapour content using Mao method. The Sobmao method has almost the same accuracy with Sobrino method. With high accuracy and simplification of water vapour content estimation, the Sobmao method is recommendable in LST inversion for good application in Ningxia region, the northwest China, with mean error of 0.33K and the RMSE value of 0.91K.

  17. A new Dobson Umkehr ozone profile retrieval method optimising information content and resolution

    Directory of Open Access Journals (Sweden)

    K. Stone

    2014-08-01

    Full Text Available The standard Dobson Umkehr methodology to retrieve coarse resolution ozone profiles used by the National Oceanographic and Atmospheric Administration uses designated solar zenith angles (SZA. However, some information may be lost if measurements lie outside the designated SZA range (between 60 and 90°, or do not conform to the fitting technique. Also, while Umkehr measurements can be taken using multiple wavelength pairs (A, C, and D, past retrieval methods have focused on a single pair (C. Here we present an Umkehr inversion method that uses measurements at all SZAs and all wavelength pairs. (Although, we caution direct comparison to other algorithms. Information content for a Melbourne, Australia (38° S, 145° E Umkehr measurement case study from 28 January 1994, with SZA range similar to that designated in previous algorithms is shown. When comparing the typical single wavelength pair with designated SZAs to the raw measurements, the total degrees of freedom (independent pieces of information increases from 3.1 to 3.4, with the majority of the information gain originating from Umkehr layers 2 + 3 and 4 (10–20 km and 25–30 km respectively. In addition to this, using all available wavelength pairs increases the total degrees of freedom to 5.2, with the most significant increases in Umkehr layers 2 + 3 to 7 and 9+ (10–40 km and 45–80 km. Investigating a case from 13 April 1970 where the measurements extend beyond the 90° SZA range gives an even further amount of information gain, with total degrees of freedom extending to 6.5. Similar increases are seen in the information content. Comparing the retrieved Melbourne Umkehr time-series with ozonesondes shows excellent agreement in layers 2 + 3 and 4 (10–20 km and 25–30 km for both C and A + C + D-pairs. Retrievals in layers 5 and 6 (25–30 km and 30–35 km consistently show lower ozone partial column compared to ozonesondes. This is likely due to and stray light effects that are

  18. A new method to retrieve salinity profiles from sea surface salinity observed by SMOS satellite

    Institute of Scientific and Technical Information of China (English)

    YANG Tingting; CHEN Zhongbiao; HE Yijun

    2015-01-01

    This paper proposes a new method to retrieve salinity profiles from the sea surface salinity (SSS) observed by the Soil Moisture and Ocean Salinity (SMOS) satellite. The main vertical patterns of the salinity profiles are firstly extracted from the salinity profiles measured by Argo using the empirical orthogonal function. To determine the time coefficients for each vertical pattern, two statistical models are developed. In the linear model, a transfer function is proposed to relate the SSS observed by SMOS (SMOS_SSS) with that measured by Argo, and then a linear relationship between the SMOS_SSS and the time coefficient is established. In the nonlinear model, the neural network is utilized to estimate the time coefficients from SMOS_SSS, months and positions of the salinity profiles. The two models are validated by comparing the salinity profiles retrieved from SMOS with those measured by Argo and the climatological salinities. The root-mean-square error (RMSE) of the linear and nonlinear model are 0.08–0.16 and 0.08–0.14 for the upper 400 m, which are 0.01–0.07 and 0.01–0.09 smaller than the RMSE of climatology. The error sources of the method are also discussed.

  19. Performance of a FieldSpec spectroradiometer for aerosol optical depth retrieval: method and preliminary results.

    Science.gov (United States)

    Bassani, Cristiana; Estellés, Víctor; Campanelli, Monica; Cavalli, Rosa Maria; Martínez-Lozano, José Antonio

    2009-04-10

    The performance of a FieldSpec spectroradiometer for retrieving aerosol optical depth (AOD) has been assessed after modifying its basic configuration in order to measure direct solar irradiance at ground level. The FieldSpec measurements were obtained during four summertime days in the years 2004 and 2005, over a Spanish agricultural site in Barrax, Albacete (30 degrees 3(') N, 2 degrees 6(') W, 700 m a.s.l.), in the framework of two European Space Agency mission remote sensing field campaigns. From the whole FieldSpec spectral domain (350-2500 nm) the AOD was extracted for channels within atmospheric windows. The instrument was calibrated by means of the standard Langley plot method, performed at a high mountain site in Italy. The AOD retrieved by the FieldSpec has been validated by comparison with the AOD obtained from a colocated CIMEL CE318 Sun photometer. The FieldSpec AOD spectra were convoluted with the CE318 filter transmission functions in order to make both datasets comparable. Our results show that both datasets are very similar (R(2) around 0.9) for all the channels from the CE318, with an average deviation of about 0.02. The temporal evolution of the AOD was accurately monitored by the FieldSpec under different atmospheric conditions, as was the case for a previously reported mineral dust intrusion. As a conclusion, the comparison performed in this study shows that the FieldSpec spectroradiometer is a suitable instrument for retrieving the AOD in different atmospheric situations.

  20. A generalized method for discriminating thermodynamic phase and retrieving cloud optical thickness and effective radius using transmitted shortwave radiance spectra

    Directory of Open Access Journals (Sweden)

    S. E. LeBlanc

    2014-06-01

    Full Text Available A new retrieval scheme for cloud optical thickness, effective radius, and thermodynamic phase was developed for ground-based measurements of cloud shortwave spectral transmittance. 15 parameters were derived to quantify spectral variations in shortwave transmittance due to absorption and scattering of liquid water and ice clouds, manifested by shifts in spectral slopes, curvatures, maxima, and minima. To retrieve cloud optical thickness and effective particle radius a weighted least square fit that matched the modeled parameters was applied. The measurements for this analysis were made with a ground-based Solar Spectral Flux Radiometer (SSFR in Boulder, Colorado, between May 2012 and January 2013. We compared the cloud optical thickness and effective radius from the new retrieval to two other retrieval methods. By using multiple spectral features, we find a closer fit (with a root mean square difference over the entire spectra of 3.1% for a liquid water cloud and 5.9% for an ice cloud between measured and modeled spectra compared to two other retrieval methods, which diverge by a root-mean-square of up to 6.4% for a liquid water cloud and 22.5% for an ice cloud. The new retrieval introduced here has an average uncertainty in effective radius (±1.2 μm smaller by factor of at least 2.5 than two other methods when applied to an ice cloud.

  1. Available Methods in Farsi-English Cross Language Information Retrieval Using Machine-readable, Bilingual Glossary

    Directory of Open Access Journals (Sweden)

    Hamid Alizadeh

    2009-12-01

    Full Text Available In this paper the impact scope of Natural Language Processing (NLP on translating search statements was determined by testing out research hypotheses. The NLP techniques employed for search statement processing included text parsing, linguistic forms identification, stopword removal, morphological analysis, and tokenization. Examination of the hypotheses indicated that using the method of translating the first equivalent term selected versus the method of selecting all equivalent terms, would contribute to increased efficiency of the review that while morphological analysis of the terms not translated by the glossary, would increase the retrieval precision cutoff, there would be no significant difference established by the lack of such analysis thereof that sentence translation as opposed to term by term translation, would increase the efficiency of Farsi-English proofreading. Other findings are also represented.

  2. Retrieval of water vapor mixing ratio from a multiple channel Raman-scatter lidar using an optimal estimation method.

    Science.gov (United States)

    Sica, R J; Haefele, A

    2016-02-01

    Lidar measurements of the atmospheric water vapor mixing ratio provide an excellent complement to radiosoundings and passive, ground-based remote sensors. Lidars are now routinely used that can make high spatial-temporal resolution measurements of water vapor from the surface to the stratosphere. Many of these systems can operate during the day and night, with operation only limited by clouds thick enough to significantly attenuate the laser beam. To enhance the value of these measurements for weather and climate studies, this paper presents an optimal estimation method (OEM) to retrieve the water vapor mixing ratio, aerosol optical depth profile, Ångstrom exponent, lidar constants, detector dead times, and measurement backgrounds from multichannel vibrational Raman-scatter lidars. The OEM retrieval provides the systematic uncertainties due to the overlap function, calibration factor, air density and Rayleigh-scatter cross sections, in addition to the random uncertainties of the retrieval due to measurement noise. The OEM also gives the vertical resolution of the retrieval as a function of height, as well as the height to which the contribution of the a priori is small. The OEM is applied to measurements made by the Meteoswiss Raman Lidar for Meteorological Observations (RALMO) in the day and night for clear and cloudy conditions. The retrieved water vapor mixing ratio is in excellent agreement with both the traditional lidar retrieval method and coincident radiosoundings.

  3. A safe and efficient method to retrieve mesenchymal stem cells from three-dimensional fibrin gels.

    Science.gov (United States)

    Carrion, Bita; Janson, Isaac A; Kong, Yen P; Putnam, Andrew J

    2014-03-01

    Mesenchymal stem cells (MSCs) display multipotent characteristics that make them ideal for potential therapeutic applications. MSCs are typically cultured as monolayers on tissue culture plastic, but there is increasing evidence suggesting that they may lose their multipotency over time in vitro and eventually cease to retain any resemblance to in vivo resident MSCs. Three-dimensional (3D) culture systems that more closely recapitulate the physiological environment of MSCs and other cell types are increasingly explored for their capacity to support and maintain the cell phenotypes. In much of our own work, we have utilized fibrin, a natural protein-based material that serves as the provisional extracellular matrix during wound healing. Fibrin has proven to be useful in numerous tissue engineering applications and has been used clinically as a hemostatic material. Its rapid self-assembly driven by thrombin-mediated alteration of fibrinogen makes fibrin an attractive 3D substrate, in which cells can adhere, spread, proliferate, and undergo complex morphogenetic programs. However, there is a significant need for simple cost-effective methods to safely retrieve cells encapsulated within fibrin hydrogels to perform additional analyses or use the cells for therapy. Here, we present a safe and efficient protocol for the isolation of MSCs from 3D fibrin gels. The key ingredient of our successful extraction method is nattokinase, a serine protease of the subtilisin family that has a strong fibrinolytic activity. Our data show that MSCs recovered from 3D fibrin gels using nattokinase are not only viable but also retain their proliferative and multilineage potentials. Demonstrated for MSCs, this method can be readily adapted to retrieve any other cell type from 3D fibrin gel constructs for various applications, including expansion, bioassays, and in vivo implantation.

  4. A Method to Retrieve Rainfall Rate Over Land from TRMM Microwave Imager Observations

    Science.gov (United States)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Over tropical land regions, rain rate maxima in mesoscale convective systems revealed by the Precipitation Radar (PR) flown on the Tropical Rainfall Measuring Mission (TRMM) satellite are found to correspond to thunderstorms, i.e., Cbs. These Cbs are reflected as minima in the 85 GHz brightness temperature, T85, observed by the TRMM Microwave Imager (TMI) radiometer. Because the magnitude of TMI observations do not discriminate satisfactorily convective and stratiform rain, we developed here a different TMI discrimination method. In this method, two types of Cbs, strong and weak, are inferred from the Laplacian of T85 at minima. Then, to retrieve rain rate, where T85 is less than 270 K, a weak (background) rain rate is deduced using T85 observations. Furthermore, over a circular area of 10 km radius centered at the location of each T85 minimum, an additional Cb component of rain rate is added to the background rain rate. This Cb component of rain rate is estimated with the help of (T19-T37) and T85 observations. Initially, our algorithm is calibrated with the PR rain rate measurements from 20 MCS rain events. After calibration, this method is applied to TMI data taken from several tropical land regions. With the help of the PR observations, we show that the spatial distribution and intensity of rain rate over land estimated from our algorithm are better than those given by the current TMI-Version-5 Algorithm. For this reason, our algorithm may be used to improve the current state of rain retrievals on land.

  5. A Multi-Channel Method for Retrieving Surface Temperature for High-Emissivity Surfaces from Hyperspectral Thermal Infrared Images

    Directory of Open Access Journals (Sweden)

    Xinke Zhong

    2015-06-01

    Full Text Available The surface temperature (ST of high-emissivity surfaces is an important parameter in climate systems. The empirical methods for retrieving ST for high-emissivity surfaces from hyperspectral thermal infrared (HypTIR images require spectrally continuous channel data. This paper aims to develop a multi-channel method for retrieving ST for high-emissivity surfaces from space-borne HypTIR data. With an assumption of land surface emissivity (LSE of 1, ST is proposed as a function of 10 brightness temperatures measured at the top of atmosphere by a radiometer having a spectral interval of 800–1200 cm−1 and a spectral sampling frequency of 0.25 cm−1. We have analyzed the sensitivity of the proposed method to spectral sampling frequency and instrumental noise, and evaluated the proposed method using satellite data. The results indicated that the parameters in the developed function are dependent on the spectral sampling frequency and that ST of high-emissivity surfaces can be accurately retrieved by the proposed method if appropriate values are used for each spectral sampling frequency. The results also showed that the accuracy of the retrieved ST is of the order of magnitude of the instrumental noise and that the root mean square error (RMSE of the ST retrieved from satellite data is 0.43 K in comparison with the AVHRR SST product.

  6. Application of the Tikhonov regularization method to wind retrieval from scatterometer data I.Sensitivity analysis and simulation experiments

    Institute of Scientific and Technical Information of China (English)

    Zhong Jian; Huang Si-Xun; Du Hua-Dong; Zhang Liang

    2011-01-01

    Scatterometer is an instrument which provides all-day and large-scale wind field information, and its application especially to wind retrieval always attracts meteorologists. Certain reasons cause large direction error, so it is important to find where the error mainly comes. Does it mainly result from the background field, the normalized radar cross-section (NRCS) or the method of wind retrieval? It is valuable to research. First, depending on SDP2.0, the simulated 'true' NRCS is calculated from the simulated 'true' wind through the geophysical model function NSCAT2. The simulated background field is configured by adding a noise to the simulated 'true' wind with the non-divergence constraint. Also, the simulated 'measured' NRCS is formed by adding a noise to the simulated 'true' NRCS. Then, the sensitivity experiments are taken, and the new method of regularization is used to improve the ambiguity removal with simulation experiments. The results show that the accuracy of wind retrieval is more sensitive to the noise in the background than in the measured NRCS; compared with the two-dimensional variational (2DVAR) ambiguity removal method, the accuracy of wind retrieval can be improved with the new method of Tikhonov regularization through choosing an appropriate regularization parameter, especially for the case of large error in the background. The work will provide important information and a new method for the wind, retrieval with real data.

  7. Evaluating the quality of ground-based microwave radiometer measurements and retrievals using detrended fluctuation and spectral analysis methods

    CERN Document Server

    Ivanova, K; Shirer, H N; Ackerman, T P; Liljegren, J C; Ausloos, M

    2001-01-01

    Time series both of microwave radiometer brightness temperature measurements at 23.8 and 31.4 GHz and of retrievals of water vapor and liquid water path from these brightness temperatures are evaluated using the detrended fluctuation analysis method. As quantified by the parameter $\\alpha$, this method (i) enables identification of the time scales over which noise dominates the time series and (ii) characterizes the temporal range of correlations in the time series. The more common spectral analysis method is also used to assess the data and its results are compared with those from detrended fluctuation analysis method. The assumption that measurements should have certain scaling properties allows the quality of the measurements to be characterized. The additional assumption that the scaling properties of the measurements of an atmospheric quantity are preserved in a useful retrieval provides a means for evaluating the retrieval itself. Applying these two assumptions to microwave radiometer measurements and r...

  8. Retrieval practice is an efficient method of enhancing the retention of anatomy and physiology information.

    Science.gov (United States)

    Dobson, John L

    2013-06-01

    Although a great deal of empirical evidence has indicated that retrieval practice is an effective means of promoting learning and memory, very few studies have investigated the strategy in the context of an actual class. The primary purpose of this study was to determine if a series of very brief retrieval quizzes could significantly improve the retention of previously tested information throughout an anatomy and physiology course. A second purpose was to determine if there were any significant differences between expanding and uniform patterns of retrieval that followed a standardized initial retrieval delay. Anatomy and physiology students were assigned to either a control group or groups that were repeatedly prompted to retrieve a subset of previously tested course information via a series of quizzes that were administered on either an expanding or a uniform schedule. Each retrieval group completed a total of 10 retrieval quizzes, and the series of quizzes required (only) a total of 2 h to complete. Final retention of the exam subset material was assessed during the last week of the semester. There were no significant differences between the expanding and uniform retrieval groups, but both retained an average of 41% more of the subset material than did the control group (ANOVA, F = 129.8, P = 0.00, ηp(2) = 0.36). In conclusion, retrieval practice is a highly efficient and effective strategy for enhancing the retention of anatomy and physiology material.

  9. A robust and efficient method for estimating enzyme complex abundance and metabolic flux from expression data.

    Science.gov (United States)

    Barker, Brandon E; Sadagopan, Narayanan; Wang, Yiping; Smallbone, Kieran; Myers, Christopher R; Xi, Hongwei; Locasale, Jason W; Gu, Zhenglong

    2015-12-01

    A major theme in constraint-based modeling is unifying experimental data, such as biochemical information about the reactions that can occur in a system or the composition and localization of enzyme complexes, with high-throughput data including expression data, metabolomics, or DNA sequencing. The desired result is to increase predictive capability and improve our understanding of metabolism. The approach typically employed when only gene (or protein) intensities are available is the creation of tissue-specific models, which reduces the available reactions in an organism model, and does not provide an objective function for the estimation of fluxes. We develop a method, flux assignment with LAD (least absolute deviation) convex objectives and normalization (FALCON), that employs metabolic network reconstructions along with expression data to estimate fluxes. In order to use such a method, accurate measures of enzyme complex abundance are needed, so we first present an algorithm that addresses quantification of complex abundance. Our extensions to prior techniques include the capability to work with large models and significantly improved run-time performance even for smaller models, an improved analysis of enzyme complex formation, the ability to handle large enzyme complex rules that may incorporate multiple isoforms, and either maintained or significantly improved correlation with experimentally measured fluxes. FALCON has been implemented in MATLAB and ATS, and can be downloaded from: https://github.com/bbarker/FALCON. ATS is not required to compile the software, as intermediate C source code is available. FALCON requires use of the COBRA Toolbox, also implemented in MATLAB.

  10. Fencing and mowing as effective methods for reducing tick abundance on very small, infested plots.

    Science.gov (United States)

    Del Fabbro, Simone

    2015-03-01

    The tick Ixodes ricinus (L.) transmits a large variety of pathogens to humans and is therefore a matter of concern for public health. Different strategies for reducing the risk of tick bite, and thus of infection, have been developed and vary according to the kind of exposure (occupational, recreational, peridomestic). The present study (carried out in an endemic region for both Lyme borreliosis and tick-borne encephalitis) aimed to assess the efficacy of two simple and cheap interventions for reducing I. ricinus abundance around residential properties surrounded by wooded areas. The immediate impact of exclosures (host-targeted control methods) and mowing (vegetation management) on very small surfaces (fencing (even if applied on very small surfaces), by preventing the entrance of tick reproductive hosts, can decrease the abundance of parasites in a short time, and that mowing can contribute to reach the goal. This control method could be of great value in small portions of heavily infested areas that have to be kept tick-free to reduce the risk of peridomestic exposure or to permit their recreational use (e.g. picnic areas within natural parks). Benefits appear even greater when considering that these interventions are environmental safe, cheap, technically simple and effective even in close proximity to heavy infested woodlands.

  11. Validation of GOES-Derived Surface Radiation Using NOAA's Physical Retrieval Method

    Energy Technology Data Exchange (ETDEWEB)

    Habte, A.; Sengupta, M.; Wilcox, S.

    2013-01-01

    This report was part of a multiyear collaboration with the University of Wisconsin and the National Oceanic and Atmospheric Administration (NOAA) to produce high-quality, satellite-based, solar resource datasets for the United States. High-quality, solar resource assessment accelerates technology deployment by making a positive impact on decision making and reducing uncertainty in investment decisions. Satellite-based solar resource datasets are used as a primary source in solar resource assessment. This is mainly because satellites provide larger areal coverage and longer periods of record than ground-based measurements. With the advent of newer satellites with increased information content and faster computers that can process increasingly higher data volumes, methods that were considered too computationally intensive are now feasible. One class of sophisticated methods for retrieving solar resource information from satellites is a two-step, physics-based method that computes cloud properties and uses the information in a radiative transfer model to compute solar radiation. This method has the advantage of adding additional information as satellites with newer channels come on board. This report evaluates the two-step method developed at NOAA and adapted for solar resource assessment for renewable energy with the goal of identifying areas that can be improved in the future.

  12. A two-step method for retrieving the longitudinal profile of an electron bunch from its coherent radiation

    CERN Document Server

    Pelliccia, Daniele

    2014-01-01

    The coherent radiation emitted by an electron bunch provides a diagnostic signal that can be used to estimate its longitudinal distribution. Commonly only the amplitude of the intensity spectrum can be measured and the associated phase must be calculated to obtain the bunch profile. Very recently an iterative method was proposed to retrieve this phase. However ambiguities associated with non-uniqueness of the solution are always present in the phase retrieval procedure. Here we present a method to overcome the ambiguity problem by first performing multiple independent runs of the phase retrieval procedure and then second, sorting the good solutions by mean of cross-correlation analysis. Results obtained with simulated bunches of various shapes and experimental measured spectra are presented, discussed and compared with the established Kramers-Kronig method. It is shown that even when the effect of the ambiguities is strong, as is the case for a double peak in the profile, the cross-correlation post-processing...

  13. The First-Integral Method and Abundant Explicit Exact Solutions to the Zakharov Equations

    Directory of Open Access Journals (Sweden)

    Yadong Shang

    2012-01-01

    Full Text Available This paper is concerned with the system of Zakharov equations which involves the interactions between Langmuir and ion-acoustic waves in plasma. Abundant explicit and exact solutions of the system of Zakharov equations are derived uniformly by using the first integral method. These exact solutions are include that of the solitary wave solutions of bell-type for n and E, the solitary wave solutions of kink-type for E and bell-type for n, the singular traveling wave solutions, periodic wave solutions of triangle functions, Jacobi elliptic function doubly periodic solutions, and Weierstrass elliptic function doubly periodic wave solutions. The results obtained confirm that the first integral method is an efficient technique for analytic treatment of a wide variety of nonlinear systems of partial differential equations.

  14. A simple and versatile cloud-screening method for MAX-DOAS retrievals

    Directory of Open Access Journals (Sweden)

    C. Gielen

    2014-06-01

    Full Text Available We present a cloud-screening method based on differential optical absorption spectroscopy (DOAS measurements, more specifically using zenith sky spectra and O4 differential slant-column densities (DSCDs. Using the colour index (CI, i.e. the ratio of the radiance at two wavelengths, we define different sky conditions including clear, thin clouds/polluted, fully-cloudy, and heavily polluted. We also flag the presence of broken and scattered clouds. The O4 absorption is a good tracer for cloud-induced light-path changes and is used to detect clouds and discriminate between instances of high aerosol optical depth (AOD and high cloud optical depth (COD. We apply our cloud screening to MAX-DOAS (multi-axis DOAS retrievals at three different sites with different typical meteorological conditions, more specifically suburban Beijing (39.75° N, 116.96° E, Brussels (50.78° N, 4.35° E and Jungfraujoch (46.55° N, 7.98° E. We find that our cloud screening performs well characterizing the different sky conditions. The flags based on the colour index are able to detect changes in visibility due to aerosols and/or (scattered clouds. The O4-based multiple-scattering flag is able to detect optically thick clouds, and is needed to correctly identify clouds for sites with extreme aerosol pollution. Removing data taken under cloudy conditions results in a better agreement, in both correlation and slope, between the AOD retrievals and measurements from other co-located instruments.

  15. Lunar surface dielectric constant,regolith thickness, and ~3He abundance distributions retrieved from the microwave brightness temperatures of CE-1 Lunar Microwave Sounder

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Lunar regolith parameters, such as physical temperature, thickness and dielectric constant, are important in studying regolith features, distribution of lunar resources and evolution of the Moon. There had been no measurement obtained by lunar-orbit-borne microwave radiometer applied to evaluate the properties of lunar regolith before CE-1 Lunar Microwave Sounder (CELMS) being launched. CEMLS is the first passive microwave radiometer in the world to sound the surface of the Moon. The brightness temperatures (TB) sensed by CELMS include complicated information on the above geophysical parameters. In this paper, algorithms of retrieving dielectric constant, regolith thickness, and 3He content from CELMS brightness temperatures are developed, and the results are compared with those from literature. The results show that the regolith thicknesses are mostly in the range of 4.0-6.0 m, and 43% of them are bigger than 5.0 m. The content of 3He evaluated by retrieved regolith thickness is about 1.03 million tons.

  16. Harmonic Retrieval Embedded in Hybrid Colored Noise: a Novel Pisarenko Method Based on Cross-high-order Cumulant

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Spectral estimation method is an effective method in the case of parameter estimation of sinusoid signal in noises.It always applies cross-spectral estimation theory and high-order self-spectral estimation methods up to now.Yule-Walker equation based on cross-fourth-order cumulant is developed and Pisarenko method is provided in this paper.Simulation results show that the method is effective to retrieve sinusoid signal frequencies from hybrid colored noises and has good performance.

  17. An automatic method for retrieving and indexing catalogues of biomedical courses.

    Science.gov (United States)

    Maojo, Victor; de la Calle, Guillermo; García-Remesal, Miguel; Bankauskaite, Vaida; Crespo, Jose

    2008-11-06

    Although there is wide information about Biomedical Informatics education and courses in different Websites, information is usually not exhaustive and difficult to update. We propose a new methodology based on information retrieval techniques for extracting, indexing and retrieving automatically information about educational offers. A web application has been developed to make available such information in an inventory of courses and educational offers.

  18. Retrieval Practice Is an Efficient Method of Enhancing the Retention of Anatomy and Physiology Information

    Science.gov (United States)

    Dobson, John L.

    2013-01-01

    Although a great deal of empirical evidence has indicated that retrieval practice is an effective means of promoting learning and memory, very few studies have investigated the strategy in the context of an actual class. The primary purpose of this study was to determine if a series of very brief retrieval quizzes could significantly improve the…

  19. Abundant soliton solutions for the coupled Schrödinger-Boussinesq system via an analytical method

    Science.gov (United States)

    Manafian, Jalil; Aghdaei, Mehdi Fazli

    2016-04-01

    In this paper, the improved tan(Φ(ξ)/2)-expansion method is proposed to find the exact soliton solutions of the coupled Schrödinger-Boussinesq (SB) system. The exact particular solutions are of five types: hyperbolic function solution (exact soliton wave solution), trigonometric function solution (exact periodic wave solution), rational exponential solution (exact singular kink-type wave solution), logarithmic solution and rational solution (exact singular cupson wave solution). We obtained the further solutions comparing with other methods. The results demonstrate that the new tan(Φ(ξ)/2)-expansion method is more efficient than the Ansatz method applied by Bilige et al. (2013). Recently this method was developed for searching the exact travelling-wave solutions of nonlinear partial differential equations. Abundant exact travelling-wave solutions including solitons, kink, periodic and rational solutions have been found. These solutions might play an important role in Laser and plasma. It is shown that this method, with the help of symbolic computation, provides a straightforward and powerful mathematical tool for solving the nonlinear problems.

  20. Methods for determining the abundance, diversity and activity of soil microbial communities

    Science.gov (United States)

    Pereg, Lily

    2014-05-01

    The diversity and abundance of soil microbial communities play important roles in determining soil structure, quality and productivity. The past decade has seen an increase in the number and efficiency of methods for determining microbial diversity, abundance and function. Recognising that only a very small proportion of the soil microbial community can be cultured, most current studies use molecular techniques based on the 16S and 18S rRNA encoding sequences (DGGE, TRFLP, OFRG, ARISA, SSCP) as well as techniques based on the cellular composition of the microbes (PLFA composition). Recent developments include high-throughput sequencing and microarrays, representing major advances in microbial community analysis. While the diversity of microbes can be determined using DNA-based techniques, microbial activity changes under various conditions. Therefore, the analysis of soil function at any given time requires the analysis of gene expression using RNA-based techniques. Molecular techniques have tremendously advanced our knowledge in the field of soil microbiology, however, the limitations should not be underestimated. This presentation will critically review both the advantages and the limitations of techniques used in soil microbial analysis.

  1. Horvitz-Thompson survey sample methods for estimating large-scale animal abundance

    Science.gov (United States)

    Samuel, M.D.; Garton, E.O.

    1994-01-01

    Large-scale surveys to estimate animal abundance can be useful for monitoring population status and trends, for measuring responses to management or environmental alterations, and for testing ecological hypotheses about abundance. However, large-scale surveys may be expensive and logistically complex. To ensure resources are not wasted on unattainable targets, the goals and uses of each survey should be specified carefully and alternative methods for addressing these objectives always should be considered. During survey design, the impoflance of each survey error component (spatial design, propofiion of detected animals, precision in detection) should be considered carefully to produce a complete statistically based survey. Failure to address these three survey components may produce population estimates that are inaccurate (biased low), have unrealistic precision (too precise) and do not satisfactorily meet the survey objectives. Optimum survey design requires trade-offs in these sources of error relative to the costs of sampling plots and detecting animals on plots, considerations that are specific to the spatial logistics and survey methods. The Horvitz-Thompson estimators provide a comprehensive framework for considering all three survey components during the design and analysis of large-scale wildlife surveys. Problems of spatial and temporal (especially survey to survey) heterogeneity in detection probabilities have received little consideration, but failure to account for heterogeneity produces biased population estimates. The goal of producing unbiased population estimates is in conflict with the increased variation from heterogeneous detection in the population estimate. One solution to this conflict is to use an MSE-based approach to achieve a balance between bias reduction and increased variation. Further research is needed to develop methods that address spatial heterogeneity in detection, evaluate the effects of temporal heterogeneity on survey

  2. Standard test method for 238Pu isotopic abundance by alpha spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This test method covers the use of alpha spectrometry for determining the 238Pu isotopic abundance in plutonium samples. It is particularly useful for samples in which the 238Pu content is less than 1 % of the total plutonium content. For such samples, mass spectrometric results are less reliable than those from alpha spectrometry because of interference from any 238U isobar remaining after ion exchange. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  3. Automatic query generation using word embeddings for retrieving passages describing experimental methods

    Science.gov (United States)

    Aydın, Ferhat; Hüsünbeyi, Zehra Melce; Özgür, Arzucan

    2017-01-01

    Information regarding the physical interactions among proteins is crucial, since protein–protein interactions (PPIs) are central for many biological processes. The experimental techniques used to verify PPIs are vital for characterizing and assessing the reliability of the identified PPIs. A lot of information about PPIs and the experimental methods are only available in the text of the scientific publications that report them. In this study, we approach the problem of identifying passages with experimental methods for physical interactions between proteins as an information retrieval search task. The baseline system is based on query matching, where the queries are generated by utilizing the names (including synonyms) of the experimental methods in the Proteomics Standard Initiative–Molecular Interactions (PSI-MI) ontology. We propose two methods, where the baseline queries are expanded by including additional relevant terms. The first method is a supervised approach, where the most salient terms for each experimental method are obtained by using the term frequency–relevance frequency (tf.rf) metric over 13 articles from our manually annotated data set of 30 full text articles, which is made publicly available. On the other hand, the second method is an unsupervised approach, where the queries for each experimental method are expanded by using the word embeddings of the names of the experimental methods in the PSI-MI ontology. The word embeddings are obtained by utilizing a large unlabeled full text corpus. The proposed methods are evaluated on the test set consisting of 17 articles. Both methods obtain higher recall scores compared with the baseline, with a loss in precision. Besides higher recall, the word embeddings based approach achieves higher F-measure than the baseline and the tf.rf based methods. We also show that incorporating gene name and interaction keyword identification leads to improved precision and F-measure scores for all three evaluated

  4. Regional content-based image retrieval for solar images: Traditional versus modern methods

    Science.gov (United States)

    Banda, J. M.; Angryk, R. A.

    2015-11-01

    This work presents an extensive evaluation between conventional (distance-based) and modern (search-engine) information retrieval techniques in the context of finding similar Solar image regions within the Solar Dynamics Observatory (SDO) mission image repository. We compare pre-computed image descriptors (image features) extracted from the SDO mission images in two very different ways: (1) similarity retrieval using multiple distance-based metrics and (2) retrieval using Lucene, a general purpose scalable retrieval engine. By transforming image descriptors into histogram-like signatures and into Lucene-compatible text strings, we are able to effectively evaluate the retrieval capabilities of both methodologies. Using the image descriptors alongside a labeled image dataset, we present an extensive evaluation under the criteria of performance, scalability and retrieval precision of experimental retrieval systems in order to determine which implementation would be ideal for a production level system. In our analysis we performed key transformations to our sample datasets to properly evaluate rotation invariance and scalability. At the end of this work we conclude which technique is the most robust and would yield the best performing system after an extensive experimental evaluation, we also point out the strengths and weaknesses of each approach and theorize on potential improvements.

  5. Comparative analysis of different retrieval methods for mapping grassland leaf area index using airborne imaging spectroscopy

    Science.gov (United States)

    Atzberger, Clement; Darvishzadeh, Roshanak; Immitzer, Markus; Schlerf, Martin; Skidmore, Andrew; le Maire, Guerric

    2015-12-01

    Fine scale maps of vegetation biophysical variables are useful status indicators for monitoring and managing national parks and endangered habitats. Here, we assess in a comparative way four different retrieval methods for estimating leaf area index (LAI) in grassland: two radiative transfer model (RTM) inversion methods (one based on look-up-tables (LUT) and one based on predictive equations) and two statistical modelling methods (one partly, the other entirely based on in situ data). For prediction, spectral data were used that had been acquired over Majella National Park in Italy by the airborne hyperspectral HyMap instrument. To assess the performance of the four investigated models, the normalized root mean squared error (nRMSE) and coefficient of determination (R2) between estimates and in situ LAI measurements are reported (n = 41). Using a jackknife approach, we also quantified the accuracy and robustness of empirical models as a function of the size of the available calibration data set. The results of the study demonstrate that the LUT-based RTM inversion yields higher accuracies for LAI estimation (R2 = 0.91, nRMSE = 0.18) as compared to RTM inversions based on predictive equations (R2 = 0.79, nRMSE = 0.38). The two statistical methods yield accuracies similar to the LUT method. However, as expected, the accuracy and robustness of the statistical models decrease when the size of the calibration database is reduced to fewer samples. The results of this study are of interest for the remote sensing community developing improved inversion schemes for spaceborne hyperspectral sensors applicable to different vegetation types. The examples provided in this paper may also serve as illustrations for the drawbacks and advantages of physical and empirical models.

  6. A new method for information retrieval in two-dimensional grating-based X-ray phase contrast imaging

    Institute of Scientific and Technical Information of China (English)

    Wang Zhi-Li; Gao Kun; Chen Jian; Ge Xin; Zhu Pei-Ping; Tian Yang-Chao; Wu Zi-Yu

    2012-01-01

    Grating-based X-ray phase contrast imaging has been demonstrated to be an extremely powerful phase-sensitive imaging technique.By using two-dimensional (2D) gratings,the observable contrast is extended to two refraction directions.Recently,we have developed a novel reverse-projection (RP) method,which is capable of retrieving the object information efficiently with one-dimensional (1D) grating-based phase contrast imaging.In this contribution,we present its extension to the 2D grating-based X-ray phase contrast imaging,named the two-dimensional reverseprojection (2D-RP) method,for information retrieval.The method takes into account the nonlinear contributions of two refraction directions and allows the retrieval of the absorption,the horizontal and the vertical refraction images.The obtained information can be used for the reconstruction of the three-dimensional phase gradient field,and for an improved phase map retrieval and reconstruction.Numerical experiments are carried out,and the results confirm the validity of the 2D-RP method.

  7. Toxoplasma gondii from liquid nitrogen for continuous cell culture: methods to maximise efficient retrieval.

    Science.gov (United States)

    Mavin, S; Evans, R; Chatterton, J M W; Ashburn, D; Joss, A W L; Ho-Yen, D O

    2003-01-01

    This study aims to increase the efficiency of continuous growth of Toxoplasma gondii in HeLa cells from tachyzoite stocks frozen in liquid nitrogen. Freezing and retrieval of tachyzoites for continuous cell culture requires more stringent protocols than those published for animal culture. The freezing and retrieval conditions are optimised so that a quality harvest (> or = 1 x 10(6) tachyzoites/mL, > or = 90% viability) can be produced using T. gondii recovered from liquid nitrogen as fast and reliably as possible. Retrieval success rate increased from 36% to 100%. An improved freezing procedure using chilled reagents and freshly harvested parasites, and adoption of an effective recovery protocol with retrieval of 3 x 10(7) tachyzoites into 75 cm2 flasks, change of maintenance media after six hours and subsequent blind passage all contributed to this success. The result is faster and more dependable production of T. gondii for diagnostic and experimental use.

  8. Contrast validation test for retrieval method of high frequency ground wave radar

    Institute of Scientific and Technical Information of China (English)

    WANG Hailong; GUO Peifang; HAN Shuzong; XIE Qiang; ZHOU Liangming

    2005-01-01

    In this paper, on the basis of the working principles of high frequency ground wave radar for retrieval of ocean wave and sea wind elements were used to systematically study the data obtained from contrast validation test in Zhoushan sea area of Zhejiang Province on Oct. 2000, to validate the accuracy of OSMAR2000for wave and wind parameters, and to analyze the possible error caused when using OSMAR2000 to retrieve ocean parameters.

  9. Three methods to retrieve slant total electron content measurements from ground-based GPS receivers and performance assessment

    Science.gov (United States)

    Zhang, Baocheng

    2016-07-01

    The high sampling rate along with the global coverage of ground-based receivers makes Global Positioning System (GPS) data particularly ideal for sensing the Earth's ionosphere. Retrieval of slant total electron content measurements (TECMs) constitutes a key first step toward extracting various ionospheric parameters from GPS data. Within the ionospheric community, the interpretation of TECM is widely recognized as the slant total electron content along the satellite receiver line of sight, biased by satellite and receiver differential code biases (DCBs). The Carrier-to-Code Leveling (CCL) has long been used as a geometry-free method for retrieving TECM, mainly because of its simplicity and effectiveness. In fact, however, the CCL has proven inaccurate as it may give rise to TECM very susceptible to so-called leveling errors. With the goal of attaining more accurate TECM retrieval, we report in this contribution two other methods than the CCL, namely, the Precise Point Positioning (PPP) and the Array-aided PPP (A-PPP). The PPP further exploits the International GPS Service (IGS) orbit and clock products and turns out to be a geometry-based method. The A-PPP is designed to retrieve TECM from an array of colocated receivers, taking advantage of the broadcast orbit and clock products. Moreover, A-PPP also takes into account the fact that the ionospheric effects measured from one satellite to all colocated receivers ought to be the same, thus leading to the estimability of interreceiver DCB. We perform a comparative study of the formal precision and the empirical accuracy of the TECM that are retrieved, respectively, by three methods from the same set of GPS data. Results of such a study can be used to assess the actual performance of the three methods. In addition, we check the temporal stability in A-PPP-derived interreceiver DCB estimates over time periods ranging from 1 to 3 days.

  10. Voxel-Based Spatial Filtering Method for Canopy Height Retrieval from Airborne Single-Photon Lidar

    Directory of Open Access Journals (Sweden)

    Hao Tang

    2016-09-01

    Full Text Available Airborne single-photon lidar (SPL is a new technology that holds considerable potential for forest structure and carbon monitoring at large spatial scales because it acquires 3D measurements of vegetation faster and more efficiently than conventional lidar instruments. However, SPL instruments use green wavelength (532 nm lasers, which are sensitive to background solar noise, and therefore SPL point clouds require more elaborate noise filtering than other lidar instruments to determine canopy heights, particularly in daytime acquisitions. Histogram-based aggregation is a commonly used approach for removing noise from photon counting lidar data, but it reduces the resolution of the dataset. Here we present an alternate voxel-based spatial filtering method that filters noise points efficiently while largely preserving the spatial integrity of SPL data. We develop and test our algorithms on an experimental SPL dataset acquired over Garrett County in Maryland, USA. We then compare canopy attributes retrieved using our new algorithm with those obtained from the conventional histogram binning approach. Our results show that canopy heights derived using the new algorithm have a strong agreement with field-measured heights (r2 = 0.69, bias = 0.42 m, RMSE = 4.85 m and discrete return lidar heights (r2 = 0.94, bias = 1.07 m, RMSE = 2.42 m. Results are consistently better than height accuracies from the histogram method (field data: r2 = 0.59, bias = 0.00 m, RMSE = 6.25 m; DRL: r2 = 0.78, bias = −0.06 m and RMSE = 4.88 m. Furthermore, we find that the spatial-filtering method retains fine-scale canopy structure detail and has lower errors over steep slopes. We therefore believe that automated spatial filtering algorithms such as the one presented here can support large-scale, canopy structure mapping from airborne SPL data.

  11. Connectionist Interaction Information Retrieval.

    Science.gov (United States)

    Dominich, Sandor

    2003-01-01

    Discussion of connectionist views for adaptive clustering in information retrieval focuses on a connectionist clustering technique and activation spreading-based information retrieval model using the interaction information retrieval method. Presents theoretical as well as simulation results as regards computational complexity and includes…

  12. Retrieving Microphysical Properties and Air Motion of Cirrus Clouds Based on the Doppler Moments Method Using Cloud Radar

    Institute of Scientific and Technical Information of China (English)

    ZHONG Lingzhi; LIU Liping; DENG Min; ZHOU Xiuji

    2012-01-01

    Radar parameters including radar reflectivity,Doppler velocity,and Doppler spectrum width were obtained from Doppler spectrum moments.The Doppler spectrum moment is the convolution of both the particle spectrum and the mean air vertical motion.Unlike strong precipitation,the motion of particles in cirrus clouds is quite close to the air motion around them.In this study,a method of Doppler moments was developed and used to retrieve cirrus cloud microphysical properties such as the mean air vertical velocity,mass-weighted diameter,effective particle size,and ice content. Ice content values were retrieved using both the Doppler spectrum method and classic Z-IWC (radar reflectivity-ice water content) relationships;however,the former is a more reasonable method.

  13. Comparison of retrieving methods of ocean wave periods from satellite altimeter with buoy measurements

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    For validating the results of retrieved mean wave period, four empirical algorithms established previously are introduced. Based on the data of over five years derived from TOPEX satellite altimeter for the entire East China Sea, ocean wave periods were calculated and statistical comparison among them was performed. The retrieved mean wave period obtained with our new distribution parameters showed better agreement with the wave period TB measured by buoy than that calculated by other three algorithms. The difference between the mean values of and that of TB is 0.16 s and the RMSE (root mean square error) of is the lowest value (0.48).

  14. Protamine sulfate precipitation method depletes abundant plant seed-storage proteins: A case study on legume plants.

    Science.gov (United States)

    Kim, Yu Ji; Wang, Yiming; Gupta, Ravi; Kim, So Wun; Min, Chul Woo; Kim, Yong Chul; Park, Ki Hun; Agrawal, Ganesh Kumar; Rakwal, Randeep; Choung, Myoung-Gun; Kang, Kyu Young; Kim, Sun Tae

    2015-05-01

    Depletion of abundant proteins is one of the effective ways to improve detection and identification of low-abundance proteins. Our previous study showed that protamine sulfate precipitation (PSP) method can deplete abundant ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) from leaf proteins and is suitable for their in-depth proteome investigation. In this study, we provide evidence that the PSP method can also be effectively used for depletion of abundant seed-storage proteins (SSPs) from the total seed proteins of diverse legume plants including soybean, broad bean, pea, wild soybean, and peanut. The 0.05% protamine sulfate (PS) was sufficient to deplete major SSPs from all legumes tested except for peanut where 0.1% PS was required. SDS-PAGE, Western blotting and 2DE analyses of PS-treated soybean and peanut seed proteins showed enriched spots in PS-supernatant than total proteins. Coefficient of variation percentage (%CV) and principal component analysis of 2DE spots support the reproducibility, suitability, and efficacy of the PSP method for quantitative and comparative seed proteome analysis. MALDI-TOF-TOF successfully identified some protein spots from soybean and peanut. Hence, this simple, reproducible, economical PSP method has a broader application in depleting plant abundant proteins including SSPs in addition to RuBisCO, allowing discussion for comprehensive proteome establishment and parallel comparative studies in plants.

  15. Errorless learning and spaced retrieval: how do these methods fare in healthy and clinical populations?

    Science.gov (United States)

    Haslam, Catherine; Hodder, Kathryn I; Yates, Philip J

    2011-04-01

    While errorless learning and spaced retrieval have both proved effective in helping many patients with acquired brain injury (ABI) and dementia learn novel information, it is not clear which of these principles we should apply to target treatment most effectively. To address this issue we conducted a systematic comparison of these principles in three experiments, comparing their effectiveness in healthy controls (N = 60), patients with ABI (N = 30), and patients with dementia (N = 15). Participants were asked to learn face-name associations, and the relative effectiveness of the principles over and above trial-and-error learning was investigated. The results were remarkably consistent across experiments: Both errorless learning and spaced retrieval produced greater accuracy in name recall than did trial-and-error learning, but recall under conditions of spaced retrieval was significantly better than that under errorless learning. We discuss the implications of these findings and suggest that spaced retrieval may be the stronger memory rehabilitation principle when it comes to learning face-name associations in people with mild to moderate memory impairment.

  16. A simple method for retrieving significant wave height from Dopplerized X-band radar

    Science.gov (United States)

    Carrasco, Ruben; Streßer, Michael; Horstmann, Jochen

    2017-02-01

    Retrieving spectral wave parameters such as the peak wave direction and wave period from marine radar backscatter intensity is very well developed. However, the retrieval of significant wave height is difficult because the radar image spectrum (a backscatter intensity variance spectrum) has to be transferred to a wave spectrum (a surface elevation variance spectrum) using a modulation transfer function (MTF) which requires extensive calibration for each individual radar setup. In contrast to the backscatter intensity, the Doppler velocity measured by a coherent radar is induced by the radial velocity (or line-of-sight velocity) of the surface scattering and its periodic component is mainly the contribution of surface waves. Therefore, the variance of the Doppler velocity can be utilized to retrieve the significant wave height. Analyzing approximately 100 days of Doppler velocity measurements of a coherent-on-receive radar operating at X-band with vertical polarization in transmit and receive, a simple relation was derived and validated to retrieve significant wave heights. Comparison to wave measurements of a wave rider buoy as well as an acoustic wave and current profiler resulted in a root mean square error of 0.24 m with a bias of 0.08 m. Furthermore, the different sources of error are discussed and investigated.

  17. User-Centered Perspective of Information Retrieval Research and Analysis Methods.

    Science.gov (United States)

    Sugar, William

    1995-01-01

    Reviews information retrieval (IR) studies since 1986 from the user's perspective. Identifies two main approaches that advocate user-centered design theory: (1) the cognitive approach; and (2) the holistic approach. Also explores other approaches--systems thinking/action research and usability techniques that may have potential for IR research and…

  18. A two-step method for retrieving the longitudinal profile of an electron bunch from its coherent radiation

    Energy Technology Data Exchange (ETDEWEB)

    Pelliccia, Daniele [School of Physics, Monash University, Victoria 3800 (Australia); Sen, Tanaji [Accelerator Physics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

    2014-11-11

    The coherent radiation emitted by an electron bunch provides a diagnostic signal that can be used to estimate its longitudinal distribution. Commonly only the amplitude of the intensity spectrum can be measured and the associated phase must be calculated to obtain the bunch profile. Very recently an iterative method was proposed to retrieve this phase. However ambiguities associated with non-uniqueness of the solution are always present in the phase retrieval procedure. Here we present a method to overcome the ambiguity problem by first performing multiple independent runs of the phase retrieval procedure and then second, sorting the good solutions by means of cross-correlation analysis. Results obtained with simulated bunches of various shapes and experimental measured spectra are presented, discussed and compared with the established Kramers–Kronig method. It is shown that even when the effect of the ambiguities is strong, as is the case for a double peak in the profile, the cross-correlation post-processing is able to filter out unwanted solutions. We show that, unlike the Kramers–Kronig method, the combined approach presented is able to faithfully reconstruct complicated bunch profiles.

  19. Method for utilizing properties of the sinc(x) function for phase retrieval on nyquist-under-sampled data

    Science.gov (United States)

    Dean, Bruce H. (Inventor); Smith, Jeffrey Scott (Inventor); Aronstein, David L. (Inventor)

    2012-01-01

    Disclosed herein are systems, methods, and non-transitory computer-readable storage media for simulating propagation of an electromagnetic field, performing phase retrieval, or sampling a band-limited function. A system practicing the method generates transformed data using a discrete Fourier transform which samples a band-limited function f(x) without interpolating or modifying received data associated with the function f(x), wherein an interval between repeated copies in a periodic extension of the function f(x) obtained from the discrete Fourier transform is associated with a sampling ratio Q, defined as a ratio of a sampling frequency to a band-limited frequency, and wherein Q is assigned a value between 1 and 2 such that substantially no aliasing occurs in the transformed data, and retrieves a phase in the received data based on the transformed data, wherein the phase is used as feedback to an optical system.

  20. Evaluation of methods to estimate lake herring spawner abundance in Lake Superior

    Science.gov (United States)

    Yule, D.L.; Stockwell, J.D.; Cholwek, G.A.; Evrard, L.M.; Schram, S.; Seider, M.; Symbal, M.

    2006-01-01

    Historically, commercial fishers harvested Lake Superior lake herring Coregonus artedi for their flesh, but recently operators have targeted lake herring for roe. Because no surveys have estimated spawning female abundance, direct estimates of fishing mortality are lacking. The primary objective of this study was to determine the feasibility of using acoustic techniques in combination with midwater trawling to estimate spawning female lake herring densities in a Lake Superior statistical grid (i.e., a 10′ latitude × 10′ longitude area over which annual commercial harvest statistics are compiled). Midwater trawling showed that mature female lake herring were largely pelagic during the night in late November, accounting for 94.5% of all fish caught exceeding 250 mm total length. When calculating acoustic estimates of mature female lake herring, we excluded backscattering from smaller pelagic fishes like immature lake herring and rainbow smelt Osmerus mordax by applying an empirically derived threshold of −35.6 dB. We estimated the average density of mature females in statistical grid 1409 at 13.3 fish/ha and the total number of spawning females at 227,600 (95% confidence interval = 172,500–282,700). Using information on mature female densities, size structure, and fecundity, we estimate that females deposited 3.027 billion (109) eggs in grid 1409 (95% confidence interval = 2.356–3.778 billion). The relative estimation error of the mature female density estimate derived using a geostatistical model—based approach was low (12.3%), suggesting that the employed method was robust. Fishing mortality rates of all mature females and their eggs were estimated at 2.3% and 3.8%, respectively. The techniques described for enumerating spawning female lake herring could be used to develop a more accurate stock–recruitment model for Lake Superior lake herring.

  1. Adjusted normalized emissivity method for surface temperature and emissivity retrieval from optical and thermal infrared remote sensing data

    OpenAIRE

    Coll Company, César; Valor i Micó, Enric; Caselles Miralles, Vicente; Niclòs Corts, Raquel

    2003-01-01

    A methodology for the retrieval of surface temperatures and emissivities combining visible, near infrared and thermal infrared remote sensing data was applied to Digital Airborne Imaging Spectrometer (DAIS) data and validated with coincident ground measurements acquired in a multiyear experiment held in an agricultural site in Barrax, Spain. The Adjusted Normalized Emissivity Method (ANEM) is based on the use of visible and near infrared data to estimate the vegetation cover and model the max...

  2. An inversion method for retrieving soil moisture information from satellite altimetry observations

    Science.gov (United States)

    Uebbing, Bernd; Forootan, Ehsan; Kusche, Jürgen; Braakmann-Folgmann, Anne

    2016-04-01

    Soil moisture represents an important component of the terrestrial water cycle that controls., evapotranspiration and vegetation growth. Consequently, knowledge on soil moisture variability is essential to understand the interactions between land and atmosphere. Yet, terrestrial measurements are sparse and their information content is limited due to the large spatial variability of soil moisture. Therefore, over the last two decades, several active and passive radar and satellite missions such as ERS/SCAT, AMSR, SMOS or SMAP have been providing backscatter information that can be used to estimate surface conditions including soil moisture which is proportional to the dielectric constant of the upper (few cm) soil layers . Another source of soil moisture information are satellite radar altimeters, originally designed to measure sea surface height over the oceans. Measurements of Jason-1/2 (Ku- and C-Band) or Envisat (Ku- and S-Band) nadir radar backscatter provide high-resolution along-track information (~ 300m along-track resolution) on backscatter every ~10 days (Jason-1/2) or ~35 days (Envisat). Recent studies found good correlation between backscatter and soil moisture in upper layers, especially in arid and semi-arid regions, indicating the potential of satellite altimetry both to reconstruct and to monitor soil moisture variability. However, measuring soil moisture using altimetry has some drawbacks that include: (1) the noisy behavior of the altimetry-derived backscatter (due to e.g., existence of surface water in the radar foot-print), (2) the strong assumptions for converting altimetry backscatters to the soil moisture storage changes, and (3) the need for interpolating between the tracks. In this study, we suggest a new inversion framework that allows to retrieve soil moisture information from along-track Jason-2 and Envisat satellite altimetry data, and we test this scheme over the Australian arid and semi-arid regions. Our method consists of: (i

  3. A Method for Retrieving Water-leaving Radiance from Landsat TM Image in Taihu Lake, East China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The visible and infrared bands of Landsat Thematic Mapper (TM) can be used for inland water studies. A method of retrieving water-leaving radiance from TM image over Taihu Lake in Jiangsu Province of China was investigated in this article. To estimate water-leaving radiance, atmospheric correction was performed in three visible bands of 485nm, 560nm and 660nm. Rayleigh scattering was computed precisely, and the aerosol contribution was estimated by adopting the clear-water-pixels approach. The clear waters were identified by using the Landsat TM middle-infrared band (2.1 μm), and the water-leaving radiance of clear water pixels in the green band was estimated by using field data.Aerosol scattering at green band was derived for six points, and interpolated to match the TM image. Assuming the atmospheric correction coefficient was 1.0, the aerosol scattering image at blue and red bands were derived. Based on a simplified atmospheric radiation transfer model, the water-leaving radiance for three visible bands was retrieved. The water-leaving radiance was normalized to make it comparable with that estimated from other remotely sensed data acquired at different times, and under different atmospheric conditions. Additionally, remotely sensed reflectance of water was computed. To evaluate the atmospheric correction method presented in this article, the correlation was analyzed between the corrected remotely sensed data and the measured water parameters based on the retrieval model. The results show that the atmospheric correction method based on the image itself is more effective for the retrieval of water parameters from Landsat TM data than 6S (Second Simulation of the Satellite Signal in the Solar Spectrum) code based on standard atmospheric and aerosol models.

  4. A distributed information retrieval method in peer-to-peer network

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To avoid the scalability of the existing systems that employed centralized indexing, index flooding or query flooding, we proposed an efficient peer-to-peer information retrieval system SPIRS (Semantic P2P-based Information Retrieval System) that supported state-of-the-art content and semantic searches. SPIRS distributes document indices through P2P network hierarchically by Latent Semantic Indexing (LSI) and organizes nodes into a hierarchical overlay through CAN and TRIE. Comparing with other P2P search techniques, those based on simple keyword matching, SPIRS has better accuracy for considering the advanced relevance among documents. Given a query, only a small number of nodes are needed for SPIRS to identify the matching documents.Furthermore, both theoretical analysis and experimental results show that SPIRS possesses higher accuracy and less logic hops.

  5. Mark-recapture and mark-resight methods for estimating abundance with remote cameras: a carnivore case study

    Science.gov (United States)

    Alanso, Robert S.; McClintock, Brett T.; Lyren, Lisa M.; Boydston, Erin E.; Crooks, Kevin R.

    2015-01-01

    Abundance estimation of carnivore populations is difficult and has prompted the use of non-invasive detection methods, such as remotely-triggered cameras, to collect data. To analyze photo data, studies focusing on carnivores with unique pelage patterns have utilized a mark-recapture framework and studies of carnivores without unique pelage patterns have used a mark-resight framework. We compared mark-resight and mark-recapture estimation methods to estimate bobcat (Lynx rufus) population sizes, which motivated the development of a new "hybrid" mark-resight model as an alternative to traditional methods. We deployed a sampling grid of 30 cameras throughout the urban southern California study area. Additionally, we physically captured and marked a subset of the bobcat population with GPS telemetry collars. Since we could identify individual bobcats with photos of unique pelage patterns and a subset of the population was physically marked, we were able to use traditional mark-recapture and mark-resight methods, as well as the new “hybrid” mark-resight model we developed to estimate bobcat abundance. We recorded 109 bobcat photos during 4,669 camera nights and physically marked 27 bobcats with GPS telemetry collars. Abundance estimates produced by the traditional mark-recapture, traditional mark-resight, and “hybrid” mark-resight methods were similar, however precision differed depending on the models used. Traditional mark-recapture and mark-resight estimates were relatively imprecise with percent confidence interval lengths exceeding 100% of point estimates. Hybrid mark-resight models produced better precision with percent confidence intervals not exceeding 57%. The increased precision of the hybrid mark-resight method stems from utilizing the complete encounter histories of physically marked individuals (including those never detected by a camera trap) and the encounter histories of naturally marked individuals detected at camera traps. This new estimator

  6. Multimedia Retrieval

    NARCIS (Netherlands)

    Blanken, H.M.; Vries, de A.P.; Blok, H.E.; Feng, L.

    2007-01-01

    Retrieval of multimedia data is different from retrieval of structured data. A key problem in multimedia databases is search, and the proposed solutions to the problem of multimedia information retrieval span a rather wide spectrum of topics outside the traditional database area, ranging from inform

  7. Evaluation of alternative age-based methods for estimating relative abundance from survey data in relation to assessment models

    DEFF Research Database (Denmark)

    Berg, Casper Willestofte; Nielsen, Anders; Kristensen, Kasper

    2014-01-01

    Indices of abundance from fishery-independent trawl surveys constitute an important source of information for many fish stock assessments. Indices are often calculated using area stratified sample means on age-disaggregated data, and finally treated in stock assessment models as independent...... observations. We evaluate a series of alternative methods for calculating indices of abundance from trawl survey data (delta-lognormal, delta-gamma, and Tweedie using Generalized Additive Models) as well as different error structures for these indices when used as input in an age-based stock assessment model...... the different indices produced. The stratified mean method is found much more imprecise than the alternatives based on GAMs, which are found to be similar. Having time-varying index variances is found to be of minor importance, whereas the independence assumption is not only violated but has significant impact...

  8. Evidence-based practice method of integrative Chinese and Western medicine based on literature retrieval through PICO question and complementary and alternative medicine topics.

    Science.gov (United States)

    Yan, Xiu-feng; Ni, Qing; Wei, Jun-ping; Xu, Hao

    2010-12-01

    An evidence-based practice method according to literature retrieval through PICO (Patients, Intervention, Comparison, Outcome) questions and complementary and alternative medicine (CAM) topics, which can obtain helpful evidence for guiding clinical practice, was introduced with a practical example in this paper. The knowledge of diseases and Western medicine treatment can be acquired by literature retrieval through PICO question, while searching by CAM topics may provide evidence for Chinese medicine (CM). Thus the author held that literature retrieval through both PICO question and CAM topics was an ideal evidence-based practice method for integrative Chinese and Western medicine (ICWM). However, since the standard in CM evidence hierarchy is still under study, the value of the CAM thematic retrieval method remains very limited. In the future, studies on the definition and hierarchy of CM evidences and the herb-drug interaction between Western and Chinese medicine during a combination therapy should be strengthened to improve the status of ICWM evidence-based practice.

  9. Application of the Markov Chain Monte Carlo method for snow water equivalent retrieval based on passive microwave measurements

    Science.gov (United States)

    Pan, J.; Durand, M. T.; Vanderjagt, B. J.

    2015-12-01

    Markov Chain Monte Carlo (MCMC) method is a retrieval algorithm based on Bayes' rule, which starts from an initial state of snow/soil parameters, and updates it to a series of new states by comparing the posterior probability of simulated snow microwave signals before and after each time of random walk. It is a realization of the Bayes' rule, which gives an approximation to the probability of the snow/soil parameters in condition of the measured microwave TB signals at different bands. Although this method could solve all snow parameters including depth, density, snow grain size and temperature at the same time, it still needs prior information of these parameters for posterior probability calculation. How the priors will influence the SWE retrieval is a big concern. Therefore, in this paper at first, a sensitivity test will be carried out to study how accurate the snow emission models and how explicit the snow priors need to be to maintain the SWE error within certain amount. The synthetic TB simulated from the measured snow properties plus a 2-K observation error will be used for this purpose. It aims to provide a guidance on the MCMC application under different circumstances. Later, the method will be used for the snowpits at different sites, including Sodankyla, Finland, Churchill, Canada and Colorado, USA, using the measured TB from ground-based radiometers at different bands. Based on the previous work, the error in these practical cases will be studied, and the error sources will be separated and quantified.

  10. Techniques and methods for estimating abundance of larval and metamorphosed sea lampreys in Great Lakes tributaries, 1995 to 2001

    Science.gov (United States)

    Slade, Jeffrey W.; Adams, Jean V.; Christie, Gavin C.; Cuddy, Douglas W.; Fodale, Michael F.; Heinrich, John W.; Quinlan, Henry R.; Weise, Jerry G.; Weisser, John W.; Young, Robert J.

    2003-01-01

    Before 1995, Great Lakes streams were selected for lampricide treatment based primarily on qualitative measures of the relative abundance of larval sea lampreys, Petromyzon marinus. New integrated pest management approaches required standardized quantitative measures of sea lamprey. This paper evaluates historical larval assessment techniques and data and describes how new standardized methods for estimating abundance of larval and metamorphosed sea lampreys were developed and implemented. These new methods have been used to estimate larval and metamorphosed sea lamprey abundance in about 100 Great Lakes streams annually and to rank them for lampricide treatment since 1995. Implementation of these methods has provided a quantitative means of selecting streams for treatment based on treatment cost and estimated production of metamorphosed sea lampreys, provided managers with a tool to estimate potential recruitment of sea lampreys to the Great Lakes and the ability to measure the potential consequences of not treating streams, resulting in a more justifiable allocation of resources. The empirical data produced can also be used to simulate the impacts of various control scenarios.

  11. Highly Sensitive Detection of Low-Abundance White Spot Syndrome Virus by a Pre-Amplification PCR Method.

    Science.gov (United States)

    Pan, Xiaoming; Zhang, Yanfang; Sha, Xuejiao; Wang, Jing; Li, Jing; Dong, Ping; Liang, Xingguo

    2017-03-28

    White spot syndrome virus (WSSV) is a major threat to the shrimp farming industry and so far there is no effective therapy for it, and thus early diagnostic of WSSV is of great importance. However, at the early stage of infection, the extremely low-abundance of WSSV DNA challenges the detection sensitivity and accuracy of PCR. To effectively detect low-abundance WSSV, here we developed a pre-amplification PCR (pre-amp PCR) method to amplify trace amounts of WSSV DNA from massive background genomic DNA. Combining with normal specific PCR, 10 copies of target WSSV genes were detected from ~10(10) magnitude of backgrounds. In particular, multiple target genes were able to be balanced amplified with similar efficiency due to the usage of the universal primer. The efficiency of the pre-amp PCR was validated by nested-PCR and quantitative PCR, and pre-amp PCR showed higher efficiency than nested-PCR when multiple targets were detected. The developed method is particularly suitable for the super early diagnosis of WSSV, and has potential to be applied in other low-abundance sample detection cases.

  12. Human factors analysis and design methods for nuclear waste retrieval systems. Human factors design methodology and integration plan

    Energy Technology Data Exchange (ETDEWEB)

    Casey, S.M.

    1980-06-01

    The purpose of this document is to provide an overview of the recommended activities and methods to be employed by a team of human factors engineers during the development of a nuclear waste retrieval system. This system, as it is presently conceptualized, is intended to be used for the removal of storage canisters (each canister containing a spent fuel rod assembly) located in an underground salt bed depository. This document, and the others in this series, have been developed for the purpose of implementing human factors engineering principles during the design and construction of the retrieval system facilities and equipment. The methodology presented has been structured around a basic systems development effort involving preliminary development, equipment development, personnel subsystem development, and operational test and evaluation. Within each of these phases, the recommended activities of the human engineering team have been stated, along with descriptions of the human factors engineering design techniques applicable to the specific design issues. Explicit examples of how the techniques might be used in the analysis of human tasks and equipment required in the removal of spent fuel canisters have been provided. Only those techniques having possible relevance to the design of the waste retrieval system have been reviewed. This document is intended to provide the framework for integrating human engineering with the rest of the system development effort. The activities and methodologies reviewed in this document have been discussed in the general order in which they will occur, although the time frame (the total duration of the development program in years and months) in which they should be performed has not been discussed.

  13. 社会科学信息检索的特点及方法%The Characteristics and Methods of Social Science Information Retrieval

    Institute of Scientific and Technical Information of China (English)

    孙会清; 王崇皓

    2015-01-01

    本文介绍了社会科学信息和社会科学信息检索的特点,在此基础上提出社会科学信息的检索方法。%On the basis of introducing the characteristics of social science information and social science information retrieval, the paper presented the methods of social science information retrieval.

  14. Improving information retrieval with dialogue mapping and concept mapping tools : training university teachers to use a new method and integrate information searching exercises into their own instruction

    OpenAIRE

    Palmgren, Virpi; Heino, Kirsi; Nevalainen, Jouni

    2007-01-01

    The Library of Helsinki University of Technology (TKK) has almost 40 years' experience in teaching information retrieval, but has recently revised its training methods. During autumn 2006 the library and the Department of Computer Science and Engineering started an interesting co-operation. New software for making mind maps, concept maps and dialogue maps are being used for structuring information retrieval. This project got a warm reception because it can be adapted throughout the university...

  15. Phase retrieval and time-frequency methods in the measurement of ultrashort laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    DeLong, K.W.; Fittinghoff, D.N.; Ladera, C.L.; Trebino, R.

    1995-02-01

    Recently several techniques have become available to measure the time- (or frequency-) dependent intensity and phase of ultrashort laser pulses. One of these, Frequency-Resolved Optical Gating (FROG), is rigorous and has achieved single-laser-shot operation. FROG combines the concepts of time-frequency analysis in the form of spectrogram generation (in order to create a two-dimensional problem), and uses a phase-retrieval-based algorithm to invert the experimental data to yield the intensity and phase of the laboratory laser pulse. In FROG it is easy to generate a spectrogram of the unknown signal, and inversion of the spectrogram to recover the signal is the main goal. Because the temporal width of a femtosecond laser pulse is much shorter than anything achievable by electronics, FROG uses the pulse to measure itself. In FROG, the laser pulse is split into two replicas of itself by a partially reflecting beamsplitter, and the two replicas interact with each other in a medium with an instantaneous nonlinear-optical response. This interaction generates a signal field that is then frequency-resolved using a spectrometer. The spectrum of the signal field is measured for all relevant values of the temporal delay between the two pulses. Here, the authors employ FROG and FROG related techniques to measure the time-dependent intensity and phase of an ultrashort laser pulse.

  16. A Comparison Between Heliosat-2 and Artificial Neural Network Methods for Global Horizontal Irradiance Retrievals over Desert Environments

    Science.gov (United States)

    Ghedira, H.; Eissa, Y.

    2012-12-01

    Global horizontal irradiance (GHI) retrievals at the surface of any given location could be used for preliminary solar resource assessments. More accurately, the direct normal irradiance (DNI) and diffuse horizontal irradiance (DHI) are also required to estimate the global tilt irradiance, mainly used for fixed flat plate collectors. Two different satellite-based models for solar irradiance retrievals have been applied over the desert environment of the United Arab Emirates (UAE). Both models employ channels of the SEVIRI instrument, onboard the geostationary satellite Meteosat Second Generation, as their main inputs. The satellite images used in this study have a temporal resolution of 15-min and a spatial resolution of 3-km. The objective of this study is to compare between the GHI retrieved using the Heliosat-2 method and an artificial neural network (ANN) ensemble method over the UAE. The high-resolution visible channel of SEVIRI is used in the Heliosat-2 method to derive the cloud index. The cloud index is then used to compute the cloud transmission, while the cloud-free GHI is computed from the Linke turbidity factor. The product of the cloud transmission and the cloud-free GHI denotes the estimated GHI. A constant underestimation is observed in the estimated GHI over the dataset available in the UAE. Therefore, the cloud-free DHI equation in the model was recalibrated to fix the bias. After recalibration, results over the UAE show a root mean square error (RMSE) value of 10.1% and a mean bias error (MBE) of -0.5%. As for the ANN approach, six thermal channels of SEVIRI were used to estimate the DHI and the total optical depth of the atmosphere (δ). An ensemble approach is employed to obtain a better generalizability of the results, as opposed to using one single weak network. The DNI is then computed from the estimated δ using the Beer-Bouguer-Lambert law. The GHI is computed from the DNI and DHI estimates. The RMSE for the estimated GHI obtained over an

  17. A 3D shape retrieval method for orthogonal fringe projection based on a combination of variational image decomposition and variational mode decomposition

    Science.gov (United States)

    Li, Biyuan; Tang, Chen; Zhu, Xinjun; Chen, Xia; Su, Yonggang; Cai, Yuanxue

    2016-11-01

    The orthogonal fringe projection technique has as wide as long practical application nowadays. In this paper, we propose a 3D shape retrieval method for orthogonal composite fringe projection based on a combination of variational image decomposition (VID) and variational mode decomposition (VMD). We propose a new image decomposition model to extract the orthogonal fringe. Then we introduce the VMD method to separate the horizontal and vertical fringe from the orthogonal fringe. Lastly, the 3D shape information is obtained by the differential 3D shape retrieval method (D3D). We test the proposed method on a simulated pattern and two actual objects with edges or abrupt changes in height, and compare with the recent, related and advanced differential 3D shape retrieval method (D3D) in terms of both quantitative evaluation and visual quality. The experimental results have demonstrated the validity of the proposed method.

  18. A simple trapping method to estimate abundances of blood-sucking flying insects in avian nests

    NARCIS (Netherlands)

    Tomás, G.; Merino, S.; Martínez-de la Puente, J.; Moreno, J.; Morales, J.; Lobato, E.

    2008-01-01

    [KEYWORDS: birds; biting midges; blackflies; blood parasite-insect vector-vertebrate host relationships; Ceratopogonidae; Culicoides; distance to water sources; insecticide treatment; sampling methods; Simuliidae

  19. A comparison of DNA collection and retrieval from two swab types (cotton and nylon flocked swab) when processed using three QIAGEN extraction methods.

    Science.gov (United States)

    Brownlow, Robert J; Dagnall, Kathryn E; Ames, Carole E

    2012-05-01

    The Metropolitan Police Service currently uses cotton swabs to retrieve DNA for forensic profiling. Recently, a new nylon flocked swab type has become available from Copan (MicroRheologics, Brescia, Italy) that it is claimed, offers increased sample recovery and release yields. If true, the flocked swab may have important applications in DNA evidence retrieval. This study examines the DNA retrieval capability of cotton and nylon flocked swabs when extracted using three common extraction platforms (QIAcube, BioRobot EZ1 and manually processed QIAamp DNA investigator kit). Results indicate that both swab types are capable of recovering high percentages of DNA (>50%); however, the extraction platform selected was shown to have a significant effect upon DNA retrieval. Across all experiments, the cotton swab combined with the spin-column extractions was shown to be most effective, with the nylon swab and BioRobot EZ1 combination being the least effective. These findings illustrate the importance of extraction method selection.

  20. Variational assimilation in combination with a regularization method for sea level pressure retrieval from QuikSCAT scatterometer data Ⅱ: simulation experiment and actual case study

    Institute of Scientific and Technical Information of China (English)

    Zhang Liang; Huang Si-Xun; Shen Chun; Shi Wei-Lai

    2011-01-01

    The sea level pressure field can be computed from sea surface winds retrieved from satellite microwave scatterometer measurements,based on variational assimilation in combination with a regularization method given in part I of this paper.First,the validity of the new method is proved with a simulation experiment.Then,a new processing procedure for the sea level pressure retrieval is built by combining the geostrophic wind,which is computed from the scatterometer 10-meter wind using the University of Washington planetary boundary layer model using this method.Finally,the feasibility of the method is proved using an actual case study.

  1. Using the Theory and Method of Information Retrieval Language to Improve the Function of Search Engine%运用情报检索语言理论与方法完善搜索引擎的功能

    Institute of Scientific and Technical Information of China (English)

    曹东; 韩全惜; 庄军

    2000-01-01

    Based on a description of the general principle of the Search Engine, the author analyzes the relationship between Information Retrieval Language and the Search Engine, points out the defects of the Search Engine in information retrieval, deems that the quality and retrieval efficiency of the Search Engine can be improved efficiently by integrating the Search Engine and Information Retrieval Language, and discusses some concrete principles and methods in integration.

  2. A New Method of Measuring 81Kr and 85Kr Abundances in Environmental Samples

    CERN Document Server

    Du, X; Bailey, K; Lehmann, B E; Lorenzo, R; Lu, Z T; Müller, P; O'Connor, T P; Sturchio, N C; Young, L

    2003-01-01

    We demonstrate a new method for determining the 81Kr/Kr ratio in environmental samples based upon two measurements: the 85Kr/81Kr ratio measured by Atom Trap Trace Analysis (ATTA) and the 85Kr/Kr ratio measured by Low-Level Counting (LLC). This method can be used to determine the mean residence time of groundwater in the range of 10^5 - 10^6 a. It requires a sample of 100 micro-l STP of Kr extracted from approximately two tons of water. With modern atmospheric Kr samples, we demonstrate that the ratios measured by ATTA and LLC are directly proportional to each other within the measurement error of +/- 10%; we calibrate the 81Kr/Kr ratio of modern air measured using this method; and we show that the 81Kr/Kr ratios of samples extracted from air before and after the development of the nuclear industry are identical within the measurement error.

  3. Methods for Retrievals of CO2 Mixing Ratios from JPL Laser Absorption Spectrometer Flights During a Summer 2011 Campaign

    Science.gov (United States)

    Menzies, Robert T.; Spiers, Gary D.; Jacob, Joseph C.

    2013-01-01

    The JPL airborne Laser Absorption Spectrometer instrument has been flown several times in the 2007-2011 time frame for the purpose of measuring CO2 mixing ratios in the lower atmosphere. This instrument employs CW laser transmitters and coherent detection receivers in the 2.05- micro m spectral region. The Integrated Path Differential Absorption (IPDA) method is used to retrieve weighted CO2 column mixing ratios. We present key features of the evolving LAS signal processing and data analysis algorithms and the calibration/validation methodology. Results from 2011 flights in various U.S. locations include observed mid-day CO2 drawdown in the Midwest and high spatial resolution plume detection during a leg downwind of the Four Corners power plant in New Mexico.

  4. Investigation of the RF-imposition method for the unsanctioned information retrieval from a telephone line

    Directory of Open Access Journals (Sweden)

    Юрий Владимирович Лыков

    2015-07-01

    Full Text Available Presented in the paper Investigations are focused on special aspects connected with selection of the carrier frequency values for realization of the RF-imposition method. For this method a possibility of the information leakage from various modern models of telephones is estimated too. It is also analyzed an efficiency of means for blocking of the information leakage by the RF-imposition method and an influence of such means on the speech signal quality during a telephone conversation

  5. A Recalibration of Strong Line Oxygen Abundance Diagnostics via the Direct Method and Implications for the High Redshift Universe

    CERN Document Server

    Brown, Jonathan S; Andrews, Brett H

    2016-01-01

    We use direct method oxygen abundances in combination with strong optical emission lines, stellar masses ($M_{\\star}$), and star formation rates (SFRs) to recalibrate the N2, O3N2, and N2O2 oxygen abundance diagnostics. We stack spectra of $\\sim$200,000 star-forming galaxies from the Sloan Digital Sky Survey in bins of $M_{\\star}$ and SFR offset from the star forming main sequence to measure the weak emission lines needed to apply the direct method. All three new calibrations are reliable to within $\\pm 0.10$ dex from $\\log(M_{\\star}/M_{\\odot}) \\sim 7.5 - 10.5$ and up to at least $200~M_{\\odot}$ yr$^{-1}$ in SFR. The N2O2 diagnostic is the least subject to systematic biases. We apply the diagnostics to galaxies in the local universe and investigate the $M_{\\star}$-$Z$-${\\rm SFR}$ relation. The N2 and O3N2 diagnostics suggest the SFR dependence of the $M_{\\star}$-$Z$-${\\rm SFR}$ relation varies with both $M_{\\star}$ and $\\Delta \\log(SSFR)$, whereas the N2O2 diagnostic suggests a nearly constant dependence on S...

  6. Standard test method for uranium and plutonium concentrations and isotopic abundances by thermal ionization mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the determination of the concentration and isotopic composition of uranium and plutonium in solutions. The purified uranium or plutonium from samples ranging from nuclear materials to environmental or bioassay matrices is loaded onto a mass spectrometric filament. The isotopic ratio is determined by thermal ionization mass spectrometry, the concentration is determined by isotope dilution. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish safety and health practices and determine the applicability of regulatory limitations prior to use.

  7. A New Method for Estimating Bacterial Abundances in Natural Samples using Sublimation

    Science.gov (United States)

    Glavin, Daniel P.; Cleaves, H. James; Schubert, Michael; Aubrey, Andrew; Bada, Jeffrey L.

    2004-01-01

    We have developed a new method based on the sublimation of adenine from Escherichia coli to estimate bacterial cell counts in natural samples. To demonstrate this technique, several types of natural samples including beach sand, seawater, deep-sea sediment, and two soil samples from the Atacama Desert were heated to a temperature of 500 C for several seconds under reduced pressure. The sublimate was collected on a cold finger and the amount of adenine released from the samples then determined by high performance liquid chromatography (HPLC) with UV absorbance detection. Based on the total amount of adenine recovered from DNA and RNA in these samples, we estimated bacterial cell counts ranging from approx. l0(exp 5) to l0(exp 9) E. coli cell equivalents per gram. For most of these samples, the sublimation based cell counts were in agreement with total bacterial counts obtained by traditional DAPI staining. The simplicity and robustness of the sublimation technique compared to the DAPI staining method makes this approach particularly attractive for use by spacecraft instrumentation. NASA is currently planning to send a lander to Mars in 2009 in order to assess whether or not organic compounds, especially those that might be associated with life, are present in Martian surface samples. Based on our analyses of the Atacama Desert soil samples, several million bacterial cells per gam of Martian soil should be detectable using this sublimation technique.

  8. Influence of DNA isolation method on the investigation of archaeal diversity and abundance in biogas plants.

    Science.gov (United States)

    Theiss, Juliane; Rother, Michael; Röske, Kerstin

    2016-09-01

    Various methods are available for DNA isolation from environmental samples. Because the chemical and biological composition of samples such as soil, sludge, or plant material is different, the effectiveness of DNA isolation can vary depending on the method applied and thus, have a substantial effect on the results of downstream analysis of the microbial community. Although the process of biogas formation is being intensely investigated, a systematic evaluation of kits for DNA isolation from material of biogas plants is still lacking. Since no DNA isolation kit specifically tailored for DNA isolation from sludge of biogas plants is available, this study compares five commercially available kits regarding their influence on downstream analyses such denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR (qPCR). The results show that not all kits are equally suited for the DNA isolation from samples of different biogas plants, but highly reproducible DGGE fingerprints as well as qPCR results across the tested samples from biogas reactors using different substrate compositions could be produced using selected kits.

  9. The Comprehensive Retrieval Method of Electromagnetic Parameters Using the Scattering Parameters of Metamaterials for Two Choices of Time-Dependent Factors

    Institute of Scientific and Technical Information of China (English)

    HOU Zhi-Ling; KONG Ling-Bao; JIN Hai-Bo; CAO Mao-Sheng; LI Xiao; QI Xin

    2012-01-01

    The electromagnetic parameters (permittivity and permeability) method, retrieved from the reflection and transmission coefficients of a slab, is presented. Improvements over existing methods, including the determination of the permittivity, permeability and impedance of the slab, are expressed as explicit functions of the S parameters for both the time-dependent factors, eiωt and e-iωt (ω is the angular frequency of the incident electromagnetic wave), and the proper selection of the sign of impedance and the real part of the refractive index. Moreover, based on the retrieving method, the calculations of the electromagnetic parameters of the conventional-material teflon slab standard sample through the experimental data of the S parameters are performed, which confirm the validity of the technique for the retrieval of electromagnetic parameters.%The electromagnetic parameters (permittivity and permeability) method,retrieved from the reflection and transmission coefficients of a slab,is presented.Improvements over existing methods,including the determination of the permittivity,permeability and impedance of the slab,are expressed as explicit functions of the S parameters for both the time-dependent factors,eiwt and e-iwt (ω is the angular frequency of the incident electromagnetic wave),and the proper selection of the sign of impedance and the real part of the refractive index.Moreover,based on the retrieving method,the calculations of the electromagnetic parameters of the conventional-material teflon slab standard sample through the experimental data of the S parameters are performed,which confirm the validity of the technique for the retrieval of electromagnetic parameters.

  10. New method for estimating bacterial cell abundances in natural samples by use of sublimation

    Science.gov (United States)

    Glavin, Daniel P.; Cleaves, H. James; Schubert, Michael; Aubrey, Andrew; Bada, Jeffrey L.

    2004-01-01

    We have developed a new method based on the sublimation of adenine from Escherichia coli to estimate bacterial cell counts in natural samples. To demonstrate this technique, several types of natural samples, including beach sand, seawater, deep-sea sediment, and two soil samples from the Atacama Desert, were heated to a temperature of 500 degrees C for several seconds under reduced pressure. The sublimate was collected on a cold finger, and the amount of adenine released from the samples was then determined by high-performance liquid chromatography with UV absorbance detection. Based on the total amount of adenine recovered from DNA and RNA in these samples, we estimated bacterial cell counts ranging from approximately 10(5) to 10(9) E. coli cell equivalents per gram. For most of these samples, the sublimation-based cell counts were in agreement with total bacterial counts obtained by traditional DAPI (4,6-diamidino-2-phenylindole) staining.

  11. Methods for semi-automated indexing for high precision information retrieval

    Science.gov (United States)

    Berrios, Daniel C.; Cucina, Russell J.; Fagan, Lawrence M.

    2002-01-01

    OBJECTIVE: To evaluate a new system, ISAID (Internet-based Semi-automated Indexing of Documents), and to generate textbook indexes that are more detailed and more useful to readers. DESIGN: Pilot evaluation: simple, nonrandomized trial comparing ISAID with manual indexing methods. Methods evaluation: randomized, cross-over trial comparing three versions of ISAID and usability survey. PARTICIPANTS: Pilot evaluation: two physicians. Methods evaluation: twelve physicians, each of whom used three different versions of the system for a total of 36 indexing sessions. MEASUREMENTS: Total index term tuples generated per document per minute (TPM), with and without adjustment for concordance with other subjects; inter-indexer consistency; ratings of the usability of the ISAID indexing system. RESULTS: Compared with manual methods, ISAID decreased indexing times greatly. Using three versions of ISAID, inter-indexer consistency ranged from 15% to 65% with a mean of 41%, 31%, and 40% for each of three documents. Subjects using the full version of ISAID were faster (average TPM: 5.6) and had higher rates of concordant index generation. There were substantial learning effects, despite our use of a training/run-in phase. Subjects using the full version of ISAID were much faster by the third indexing session (average TPM: 9.1). There was a statistically significant increase in three-subject concordant indexing rate using the full version of ISAID during the second indexing session (p < 0.05). SUMMARY: Users of the ISAID indexing system create complex, precise, and accurate indexing for full-text documents much faster than users of manual methods. Furthermore, the natural language processing methods that ISAID uses to suggest indexes contributes substantially to increased indexing speed and accuracy.

  12. INTELLIGENT INFORMATION RETRIEVAL WITHIN DIGITAL LIBRARY USING DOMAIN ONTOLOGY

    Directory of Open Access Journals (Sweden)

    Thinn Mya Mya Swe

    2011-07-01

    Full Text Available A digital library is a type of information retrieval (IR system. The existing information retrieval methodologies generally have problems on keyword-searching. We proposed a model to solve the problem by using concept-based approach (ontology and metadata case base. This model consists of identifying domain concepts in user’s query and applying expansion to them. The system aims at contributing to an improved relevance of results retrieved from digital libraries by proposing a conceptual query expansion for intelligent concept-based retrieval. We need to import the concept of ontology, making use of its advantage of abundant semantics and standard concept. Domain specific ontology can be used to improve information retrieval from traditional level based on keyword to the lay based on knowledge (or concept and change the process of retrieval from traditional keyword matching to semantics matching. One approach is query expansion techniques using domain ontology and the other would be introducing a case based similarity measure for metadata information retrieval using Case Based Reasoning (CBR approach. Results show improvements over classic method, query expansion using general purpose ontology and a number of other approaches.

  13. Retrieval of Airborne Lidar Misalignments Based on the Stepwise Geometric Method

    DEFF Research Database (Denmark)

    Zhang, Xiaohong; Forsberg, René

    2010-01-01

    on the relationship between the point clouds on a regular object, e.g. a flat top building, and the ground truth of the objects used for calibration. In order to extract the footprints on the objects, filtering is implemented before the calibration. The tests verify that the proposed method is feasible, and very...

  14. A method for the automated, reliable retrieval of publication-citation records.

    Directory of Open Access Journals (Sweden)

    Derek Ruths

    Full Text Available BACKGROUND: Publication records and citation indices often are used to evaluate academic performance. For this reason, obtaining or computing them accurately is important. This can be difficult, largely due to a lack of complete knowledge of an individual's publication list and/or lack of time available to manually obtain or construct the publication-citation record. While online publication search engines have somewhat addressed these problems, using raw search results can yield inaccurate estimates of publication-citation records and citation indices. METHODOLOGY: In this paper, we present a new, automated method that produces estimates of an individual's publication-citation record from an individual's name and a set of domain-specific vocabulary that may occur in the individual's publication titles. Because this vocabulary can be harvested directly from a research web page or online (partial publication list, our method delivers an easy way to obtain estimates of a publication-citation record and the relevant citation indices. Our method works by applying a series of stringent name and content filters to the raw publication search results returned by an online publication search engine. In this paper, our method is run using Google Scholar, but the underlying filters can be easily applied to any existing publication search engine. When compared against a manually constructed data set of individuals and their publication-citation records, our method provides significant improvements over raw search results. The estimated publication-citation records returned by our method have an average sensitivity of 98% and specificity of 72% (in contrast to raw search result specificity of less than 10%. When citation indices are computed using these records, the estimated indices are within of the true value 10%, compared to raw search results which have overestimates of, on average, 75%. CONCLUSIONS: These results confirm that our method provides

  15. X-ray standing wave simulations based on Fourier vector analysis as a method to retrieve complex molecular adsorption geometries

    Directory of Open Access Journals (Sweden)

    Giuseppe eMercurio

    2014-01-01

    Full Text Available We present an analysis method of normal incidence x-ray standing wave (NIXSW data that allows detailed adsorption geometries of complex molecules to be retrieved. This method (Fourier vector analysis is based on the comparison of both the coherence and phase of NIXSW data to NIXSW simulations of different molecular geometries as the relevant internal degrees of freedom are tuned. We introduce this analysis method using the prototypical molecular switch azobenzene (AB adsorbed on the Ag(111 surface as a model system. The application of the Fourier vector analysis to AB/Ag(111 provides, on the one hand, detailed adsorption geometries including dihedral angles, and on the other hand, insights into the dynamics of molecules and their bonding to the metal substrate. This analysis scheme is generally applicable to any adsorbate, it is necessary for molecules with potentially large distortions, and will be particularly valuable for molecules whose distortion on adsorption can be mapped on a limited number of internal degrees of freedom.

  16. A Method to Retrieve the Multi-Receiver Moho Reflection Response from SH-Wave Scattering Coda in the Radiative Transfer Regime

    Science.gov (United States)

    Hartstra, I.; Wapenaar, C. P. A.

    2015-12-01

    We discuss a method to retrieve the multi-receiver Moho reflection response by interferometry from SH-wave coda in the 0.5-3 Hz frequency range. An image derived from a reflection response with a well defined virtual source would provide deterministic impedance contrasts, which can complement transmission tomography. For an accurate retrieval, cross-correlation interferometry requires the coda wave field to sample the imaging target and isotropically illuminate the receiver array. When these illumination requirements are not or only partially met, the stationary phase cannot be fully captured and artifacts will contaminate the retrieved reflection response. Here we conduct numerical scalar 2D finite difference simulations to investigate the challenging situation in which only shallow crustal earthquake sources illuminate the Moho and the response is recorded by a 2D linear array. We quantify to what extent the prevalence of scatterers in the crust can improve the illumination conditions and thus the retrieval of the Moho reflection. The accuracy of the retrieved reflection is evaluated for two physically different scattering regimes: the Rayleigh and Mie regime. We only use the earlier part of the scattering coda, because we have found that the later diffusive part does not significantly improve the retrieval. The density of the spherical scatterers is varied in order to change the scattering mean free path. This characteristic length scale is calculated for each model with the 2D radiative transfer equation, which is the governing equation in the earlier part of the scattering coda. The experiment is repeated for models of different geological settings derived from existing S-wave tomographies, which vary in Moho depth and reflectivity. The scattering mean free path can be approximated for real data if intrinsic attenuation is known, because the wavenumber-dependent scattering attenuation of the coherent wave amplitude is dependent on the scattering mean free path

  17. Method for Face-Emotion Retrieval Using A Cartoon Emotional Expression Approach

    Science.gov (United States)

    Kostov, Vlaho; Yanagisawa, Hideyoshi; Johansson, Martin; Fukuda, Shuichi

    A simple method for extracting emotion from a human face, as a form of non-verbal communication, was developed to cope with and optimize mobile communication in a globalized and diversified society. A cartoon face based model was developed and used to evaluate emotional content of real faces. After a pilot survey, basic rules were defined and student subjects were asked to express emotion using the cartoon face. Their face samples were then analyzed using principal component analysis and the Mahalanobis distance method. Feature parameters considered as having relations with emotions were extracted and new cartoon faces (based on these parameters) were generated. The subjects evaluated emotion of these cartoon faces again and we confirmed these parameters were suitable. To confirm how these parameters could be applied to real faces, we asked subjects to express the same emotions which were then captured electronically. Simple image processing techniques were also developed to extract these features from real faces and we then compared them with the cartoon face parameters. It is demonstrated via the cartoon face that we are able to express the emotions from very small amounts of information. As a result, real and cartoon faces correspond to each other. It is also shown that emotion could be extracted from still and dynamic real face images using these cartoon-based features.

  18. The Von Kármán constant retrieved from CASES-97 dataset using a variational method

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2008-12-01

    Full Text Available A variational method is developed to retrieve the von Kármán constant κ from the CASES-97 dataset, collected near Wichita, Kansas, the United States from 6 April to 24 May 1997. In the variational method, a cost function is defined to measure the difference between observed and computed gradients of wind speed, air temperature and specific humidity. An optimal estimated von Kármán constant is obtained by minimizing the cost function through adjusting values of the von Kármán constant. Under neutral stratification, the variational analysis confirms the conventional value of κ (=0.40. For non-neutral stratification, however, κ varies with stability. The computational results show that the κ decreases monotonously from stable to unstable stratification. The variational calculated mean value of the von Kármán constant is 0.383~0.390 when the atmospheric stratification is taken into consideration. Relations between κ and surface momentum and heat flux are also examined.

  19. A LiDAR method of canopy structure retrieval for wind modeling of heterogeneous forests

    DEFF Research Database (Denmark)

    Boudreault, Louis-Etienne; Bechmann, Andreas; Taryainen, Lasse

    2015-01-01

    The difficulty of obtaining accurate information about the canopy structure is a current limitation towards higher accuracy in numerical predictions of the wind field in forested terrain. The canopy structure in computational fluid dynamics is specified through the frontal area density and this i......The difficulty of obtaining accurate information about the canopy structure is a current limitation towards higher accuracy in numerical predictions of the wind field in forested terrain. The canopy structure in computational fluid dynamics is specified through the frontal area density...... and this information is required for each grid point in the three-dimensional computational domain. By using raw data from aerial LiDAR scans together with the Beer-Lambert law, we propose and test a method to calculate and grid highly variable and realistic frontal area density input. An extensive comparison...

  20. Research on the method for retrieving soil moisture using thermal inertia model

    Institute of Scientific and Technical Information of China (English)

    LIU; Zhenhua; ZHAO; Yingshi

    2006-01-01

    In order to improve accuracy of soil moisture inversion using remote sensing, a new thermal inertia model is proposed in this paper. The improved model needs only surface maximum temperature as the temperature parameter input instead of input of the surface temperature difference, as well as the surface sensible and latent fluxes are introduced into boundary conditions of thermal conductivity equation. Furthermore, surface soil conductive heat transfer equation of two-layer model is used to solve the soil thermal inertia so that the remote sensing thermal inertia method can be applied to regions with better-covered vegetation, but usually only for the bare areas or worse vegetation covered areas. The model has been tested at several locations in the area of west Inner Mongolia. Comparing the simulation of the new model with the measurements obtained by apparent thermal inertia and by field test, the result shows that the inertia thermal model can be used to estimate soil moisture in more reasonable accuracy.

  1. A Retrieval Method of Surveying and Mapping Books Based on Ontology%一种基于本体的测绘图书检索方法

    Institute of Scientific and Technical Information of China (English)

    徐洪秀; 孙立志; 樊红

    2014-01-01

    Different from traditional surveying and mapping retrieval keyword matching and query mechanism ,a re-trieval method of surveying and mapping books based on ontology is proposed , through the construction of surveying and mapping information ontology and ontology mapping model according to the heterogeneous data source of books to deal with the retrieval request ,the semantic retrieval system of the surveying and mapping books based on the oracle 11g semantic techniques is designed and implemented and also book's retrieve which about the Information Technology Library of Wuhan University Library are tested ,the results show that the method can improve the retrieval precision and comprehensive .%区别于传统的测绘图书检索以关键词进行匹配和查询的机制,提出在测绘图书检索中加入语义技术,通过构建测绘信息本体库及针对图书资料数据存在着数据源异构问题构建本体映射模型来处理检索请求,基于Oracle 11g语义技术设计并实现测绘学科图书语义检索原型系统,以武汉大学图书馆信息科学分馆图书数据为检索对象进行检索实验,结果表明该方法可提高检索的查准性和查全性。

  2. Characterization of anthropogenic methane plumes with the Hyperspectral Thermal Emission Spectrometer (HyTES): a retrieval method and error analysis

    Science.gov (United States)

    Kuai, Le; Worden, John R.; Li, King-Fai; Hulley, Glynn C.; Hopkins, Francesca M.; Miller, Charles E.; Hook, Simon J.; Duren, Riley M.; Aubrey, Andrew D.

    2016-07-01

    We introduce a retrieval algorithm to estimate lower tropospheric methane (CH4) concentrations from the surface to 1 km with uncertainty estimates using Hyperspectral Thermal Emission Spectrometer (HyTES) airborne radiance measurements. After resampling, retrievals have a spatial resolution of 6 × 6 m2. The total error from a single retrieval is approximately 20 %, with the uncertainties determined primarily by noise and spectral interferences from air temperature, surface emissivity, and atmospheric water vapor. We demonstrate retrievals for a HyTES flight line over storage tanks near Kern River Oil Field (KROF), Kern County, California, and find an extended plume structure in the set of observations with elevated methane concentrations (3.0 ± 0.6 to 6.0 ± 1.2 ppm), well above mean concentrations (1.8 ± 0.4 ppm) observed for this scene. With typically a 20 % estimated uncertainty, plume enhancements with more than 1 ppm are distinguishable from the background values with its uncertainty. HyTES retrievals are consistent with simultaneous airborne and ground-based in situ CH4 mole fraction measurements within the reported accuracy of approximately 0.2 ppm (or ˜ 8 %), due to retrieval interferences related to air temperature, emissivity, and H2O.

  3. A Solar Reflectance Method for Retrieving Cloud Optical Thickness and Droplet Size Over Snow and Ice Surfaces

    Science.gov (United States)

    Platnick, S.; Li, J. Y.; King, M. D.; Gerber, H.; Hobbs, P. V.

    1999-01-01

    Cloud optical thickness and effective radius retrievals from solar reflectance measurements are traditionally implemented using a combination of spectral channels that are absorbing and non-absorbing for water particles. Reflectances in non-absorbing channels (e.g., 0.67, 0.86, 1.2 micron spectral window bands) are largely dependent on cloud optical thickness, while longer wavelength absorbing channels (1.6, 2. 1, and 3.7 micron window bands) provide cloud particle size information. Cloud retrievals over ice and snow surfaces present serious difficulties. At the shorter wavelengths, ice is bright and highly variable, both characteristics acting to significantly increase cloud retrieval uncertainty. In contrast, reflectances at the longer wavelengths are relatively small and may be comparable to that of dark open water. A modification to the traditional cloud retrieval technique is devised. The new algorithm uses only a combination of absorbing spectral channels for which the snow/ice albedo is relatively small. Using this approach, retrievals have been made with the MODIS Airborne Simulator (MAS) imager flown aboard the NASA ER-2 from May - June 1998 during the Arctic FIRE-ACE field deployment. Data from several coordinated ER-2 and University of Washington CV-580 in situ aircraft observations of liquid water stratus clouds are examined. MAS retrievals of optical thickness, droplet effective radius, and liquid water path are shown to be in good agreement with the in situ measurements. The initial success of the technique has implications for future operational satellite cloud retrieval algorithms in polar and wintertime regions.

  4. Analysis of thickness fields retrieved from NOAA-7 observations through the 3I (Improved Initialization Inversion) method. Interest for weather forecasting

    Science.gov (United States)

    Chedin, A.; Scott, N. A.; Flobert, J.; Husson, N.; Levy, C.; Rochard, G.; Quere, J.; Bellec, B.; Simeon, J.

    1987-08-01

    The improved initialization inversion method for the 3 dimensional analysis of the atmospheric structure from satellite obsevations (TIROS-N series) was applied to NOAA-7 data over Europe. The scenes selected correspond to complex meteorological situations and resulted in substantial errors in forecasting. One of the situations is presented. Comparisons between retrieved and operational (conventional) thickness charts show that the method is ready for operational use.

  5. A novel method for efficient and abundant production of Phytophthora brassicae zoospores on Brussels sprout leaf discs

    Directory of Open Access Journals (Sweden)

    Govers Francine

    2009-08-01

    Full Text Available Abstract Background Phytophthora species are notorious oomycete pathogens that cause diseases on a wide range of plants. Our understanding how these pathogens are able to infect their host plants will benefit greatly from information obtained from model systems representative for plant-Phytophthora interactions. One attractive model system is the interaction between Arabidopsis and Phytophthora brassicae. Under laboratory conditions, Arabidopsis can be easily infected with mycelial plugs as inoculum. In the disease cycle, however, sporangia or zoospores are the infectious propagules. Since the current P. brassicae zoospore isolation methods are generally regarded as inefficient, we aimed at developing an alternative method for obtaining high concentrations of P. brassicae zoospores. Results P. brassicae isolates were tested for pathogenicity on Brussels sprout plants (Brassica oleracea var. gemmifera. Microscopic examination of leaves, stems and roots infected with a GFP-tagged transformant of P. brassicae clearly demonstrated the susceptibility of the various tissues. Leaf discs were cut from infected Brussels sprout leaves, transferred to microwell plates and submerged in small amounts of water. In the leaf discs the hyphae proliferated and abundant formation of zoosporangia was observed. Upon maturation the zoosporangia released zoospores in high amounts and zoospore production continued during a period of at least four weeks. The zoospores were shown to be infectious on Brussels sprouts and Arabidopsis. Conclusion The in vitro leaf disc method established from P. brassicae infected Brussels sprout leaves facilitates convenient and high-throughput production of infectious zoospores and is thus suitable to drive small and large scale inoculation experiments. The system has the advantage that zoospores are produced continuously over a period of at least one month.

  6. Potential and limitations of the MAX-DOAS method to retrieve the vertical distribution of tropospheric nitrogen dioxide

    Directory of Open Access Journals (Sweden)

    T. Vlemmix

    2011-06-01

    Full Text Available Muliple Axis Differential Optical Absorption Spectroscopy (MAX-DOAS instruments can measure from the ground the absorption by nitrogen dioxide (NO2 of scattered sunlight seen in multiple viewing directions. This paper studies the potential of this technique to derive the vertical distribution of NO2 in the troposphere. Such profile information is essential in validation studies in which MAX-DOAS retrievals play a role.

    The retrieval algorithm used is based on a pre-calculated look-up table and assumes homogeneous mixing of aerosols and NO2 in layers extending from the surface to a variable height. Two retrieval models are compared: one including and one excluding an elevated NO2 layer at a fixed altitude in the free troposphere. An ensemble technique is applied to derive retrieved model uncertainties.

    Sensitivity studies demonstrate that MAX-DOAS based retrievals can make a distinction between an NO2 layer that extends from the surface to a certain height (having a constant mixing ratio, or a mixing ratio that decreases with altitude and an elevated NO2 layer. The height of the elevated NO2 layer can only be retrieved accurately when the aerosol extinction profile is known and the measurement noise is low. The uncertainty in this elevated NO2 layer height provides the main source of uncertainty in the retrieval of the free tropospheric contribution to the tropospheric NO2 column.

    A comparison was performed with independent data, based on observations done at the CINDI campaign, held in the Netherlands in 2009. Comparison with lidar partial tropospheric NO2 columns showed a correlation of 0.78, and an average difference of 0.1× 1015 molec cm−2. The diurnal evolution of the NO2 volume mixing ratio measured by in-situ monitors at the surface and averaged over five days with

  7. 基于人工鱼群算法的彩色图像检索方法%Color image retrieval method based on artificial fish algorithm

    Institute of Scientific and Technical Information of China (English)

    薛亚娣; 阮文惠

    2016-01-01

    针对传统的彩色图像检索方法计算过程复杂,相似图像匹配度低,检索过程无法实现最优组合的问题,提出一种基于人工鱼群算法的彩色图像检索方法。通过介绍人工鱼群算法,完成彩色图像的颜色特征提取,进行彩色图像鱼群算法的相似度匹配,实现人工鱼群算法图像检索,完成人工鱼群算法检索图像权重的优化。仿真实验表明,提出的人工鱼群算法具备有效性,在实际环境中有检索优势。%The traditional color image retrieval method has complex calculation process,low similar image matching degree,and it unable to achieve the optimal combination in retrieval process.A color image retrieval method based on artificial fish swarm algorithm is thus pro-posed.By introducing the algorithm,the color feature extraction of color image is completed, similarity matching of fish algorithm conducted,the image retrieval realized,and retrieved im-age weight optimization complished.The simulation results show that the proposed artificial fish swarm algorithm is effective,and it has a certain advantage in the actual environment.

  8. Seeding method influences warm-season grass abundance and distribution but not local diversity in grassland restoration

    Science.gov (United States)

    Yurkonis, Kathryn A.; Wilsey, Brian J.; Moloney, Kirk A.; Drobney, Pauline; Larson, Diane L.

    2010-01-01

    Ecological theory predicts that the arrangement of seedlings in newly restored communities may influence future species diversity and composition. We test the prediction that smaller distances between neighboring seeds in drill seeded grassland plantings would result in lower species diversity, greater weed abundance, and larger conspecific patch sizes than otherwise similar broadcast seeded plantings. A diverse grassland seed mix was either drill seeded, which places seeds in equally spaced rows, or broadcast seeded, which spreads seeds across the ground surface, into 24 plots in each of three sites in 2005. In summer 2007, we measured species abundance in a 1 m2 quadrat in each plot and mapped common species within the quadrat by recording the most abundant species in each of 64 cells. Quadrat-scale diversity and weed abundance were similar between drilled and broadcast plots, suggesting that processes that limited establishment and controlled invasion were not affected by such fine-scale seed distribution. However, native warm-season (C4) grasses were more abundant and occurred in less compact patches in drilled plots. This difference in C4 grass abundance and distribution may result from increased germination or vegetative propagation of C4 grasses in drilled plots. Our findings suggest that local plant density may control fine-scale heterogeneity and species composition in restored grasslands, processes that need to be further investigated to determine whether seed distributions can be manipulated to increase diversity in restored grasslands.

  9. A method to suppress spurious multiples in virtual-source gathers retrieved using seismic interferometry with reflection data

    NARCIS (Netherlands)

    Boullenger, B.; Wapenaar, C.P.A.; Draganov, D.S.

    2014-01-01

    Seismic interferometry applied to surface reflection data (with source and receivers at the surface) allows to retrieve virtual-source gathers at the position of receivers, where no source was shot. As a result of the crosscorrelation of all primary and multiple reflections, the virtual-source gathe

  10. Parameterized first-guess spectrum method for retrieving directional spectrum of swell-dominated waves and huge waves from SAR images

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A method to retrieve ocean wave spectra from SAR images, named Parameterized First-guess Spectrum Method (PFSM), was proposed after interpretation of the theory to ocean wave imaging and analysis of the drawbacks of the retrieving model generally used. In this method, with additional information and satellite parameters, the separating wave-number is first calculated to determine the maximum wave-number beyond which the linear relation can be used. The separating wave-number can be calculated using the additional information on wind velocity and parameters of SAR satellite. And then the SAR spectrum can be divided into SAR spectrum of wind wave and of swell according to the result of separating wave-number. The portion of SAR spectrum generated by wind wave, is used to search for the most suitable parameters of ocean wind wave spectrum, including propagation direction of ocean wave, phase speed of dominating wave and the angle spreading coefficient. The swell spectrum is acquired by directly inversing the linear relation of ocean wave spectrum to SAR spectrum given the portion of SAR spectrum generated by swell. We used the proposed method to retrieve the ocean wave spectrum from ERS-SAR data from the South China Sea and compared the result with altimeter data. The agreement indicates that the PFSM is reliable.

  11. A fast method for the retrieval of integrated longwave and shortwave top-of-atmosphere upwelling irradiances from MSG/SEVIRI (RRUMS

    Directory of Open Access Journals (Sweden)

    M. Vázquez-Navarro

    2013-10-01

    Full Text Available A new Rapid Retrieval of Upwelling irradiances from MSG/SEVIRI (RRUMS is presented. It has been developed to observe the top-of-atmosphere irradiances of small scale and rapidly changing features that are not sufficiently resolved by specific Earth radiation budget sensors. Our retrieval takes advantage of the spatial and temporal resolution of MSG/SEVIRI and provides outgoing longwave and reflected shortwave radiation only by means of a combination of SEVIRI channels. The longwave retrieval is based on a simple linear combination of brightness temperatures from the SEVIRI infrared channels. The shortwave retrieval is based on a neural network that requires as input the visible and near-infrared SEVIRI channels. Both LW and SW algorithms have been validated by comparing their results with CERES and GERB irradiance observations. While being less accurate than their dedicated counterparts, the SEVIRI-based methods have two major advantages compared to CERES and GERB: their higher spatial resolution and the better temporal resolution. With our retrievals it is possible to observe the radiative effect of small-scale features such as cumulus clouds, cirrus clouds, or aircraft contrails. The spatial resolution of SEVIRI is 3 km × 3 km in the sub-satellite point, remarkably better than that of CERES (20 km or GERB (45 km. The temporal resolution is 15 min (5 min in the Rapid-Scan mode, the same as GERB, but significantly better than that of CERES which, being on board of a polar orbiting satellite, has a temporal resolution as low as 2 overpasses per day.

  12. A Framework for Quantifying the Impacts of Sub-Pixel Reflectance Variance and Covariance on Cloud Optical Thickness and Effective Radius Retrievals Based on the Bi-Spectral Method.

    Science.gov (United States)

    Zhang, Z; Werner, F.; Cho, H. -M.; Wind, Galina; Platnick, S.; Ackerman, A. S.; Di Girolamo, L.; Marshak, A.; Meyer, Kerry

    2017-01-01

    The so-called bi-spectral method retrieves cloud optical thickness (t) and cloud droplet effective radius (re) simultaneously from a pair of cloud reflectance observations, one in a visible or near infrared (VIS/NIR) band and the other in a shortwave-infrared (SWIR) band. A cloudy pixel is usually assumed to be horizontally homogeneous in the retrieval. Ignoring sub-pixel variations of cloud reflectances can lead to a significant bias in the retrieved t and re. In this study, we use the Taylor expansion of a two-variable function to understand and quantify the impacts of sub-pixel variances of VIS/NIR and SWIR cloud reflectances and their covariance on the t and re retrievals. This framework takes into account the fact that the retrievals are determined by both VIS/NIR and SWIR band observations in a mutually dependent way. In comparison with previous studies, it provides a more comprehensive understanding of how sub-pixel cloud reflectance variations impact the t and re retrievals based on the bi-spectral method. In particular, our framework provides a mathematical explanation of how the sub-pixel variation in VIS/NIR band influences the re retrieval and why it can sometimes outweigh the influence of variations in the SWIR band and dominate the error in re retrievals, leading to a potential contribution of positive bias to the re retrieval.

  13. An On-Demand Retrieval Method Based on Hybrid NoSQL for Multi-Layer Image Tiles in Disaster Reduction Visualization

    Directory of Open Access Journals (Sweden)

    Linyao Qiu

    2017-01-01

    Full Text Available Monitoring, response, mitigation and damage assessment of disasters places a wide variety of demands on the spatial and temporal resolutions of remote sensing images. Images are divided into tile pyramids by data sources or resolutions and published as independent image services for visualization. A disaster-affected area is commonly covered by multiple image layers to express hierarchical surface information, which generates a large amount of namesake tiles from different layers that overlay the same location. The traditional tile retrieval method for visualization cannot distinguish between distinct layers and traverses all image datasets for each tile query. This process produces redundant queries and invalid access that can seriously affect the visualization performance of clients, servers and network transmission. This paper proposes an on-demand retrieval method for multi-layer images and defines semantic annotations to enrich the description of each dataset. By matching visualization demands with the semantic information of datasets, this method automatically filters inappropriate layers and finds the most suitable layer for the final tile query. The design and implementation are based on a two-layer NoSQL database architecture that provides scheduling optimization and concurrent processing capability. The experimental results reflect the effectiveness and stability of the approach for multi-layer retrieval in disaster reduction visualization.

  14. Research on Part Case Retrieval Method Based on Process Similarity%基于工艺相似的零件实例检索方法研究

    Institute of Scientific and Technical Information of China (English)

    陈静; 龚志伟; 刘黎; 成阳

    2012-01-01

    实例表示与相似实例检索是基于实例推理CAPP工艺决策的关键.依据零件形状特征信息模型,建立零件形状特征实例表示模型,提出基于工艺相似的零件实例多层次检索方法.分析了基于工艺相似的零件形状特征间的可比性,给出了复合特征层、基本特征层和简单特征层的零件形状相似度计算和零件实例检索方法,并以箱体零件为例验证了复合特征层零件形状相似度计算方法的有效性.%Case representation and similar case retrieval were the keys to the CAPP technology decision based on case reasoning. A case representation model of part shape feature was built based on information model of part shape feature. A multilayer part case retrieval method was proposed, which was based on process similarity. The comparability between part shape features was analyzed based on process similarity. The part form similarity calculation and part case retrieval methods in compound feature layer, basic characteristic layer and simple feature layer were presented. The validity of this part case retrieval method on compound feature layer was verified by an example of box part.

  15. Adaptive MGS Phase Retrieval

    Science.gov (United States)

    Basinger, Scott A.; Bikkannavar, Siddarayappa; Cohen, David; Green, Joseph J.; Lou, John; Ohara, Catherine; Redding, David; Shi, Fang

    2008-01-01

    Adaptive MGS Phase Retrieval software uses the Modified Gerchberg-Saxton (MGS) algorithm, an image-based sensing method that can turn any focal plane science instrument into a wavefront sensor, avoiding the need to use external metrology equipment. Knowledge of the wavefront enables intelligent control of active optical systems.

  16. Visual indexing and retrieval

    Directory of Open Access Journals (Sweden)

    Mohammadamin Erfanmanesh

    2014-06-01

    Full Text Available This book includes a preface, a table of contents, six informative chapters and expansive references. In the preface, the editors of the book claim that with the advent of social networks, vast amount of visual information is available for end-users. Therefore, they need innovative and fruitful methods for content understanding, retrieval and classification.

  17. Human factors analysis and design methods for nuclear waste retrieval systems: Human factors design methodology and integration plan

    Science.gov (United States)

    Casey, S. M.

    1980-06-01

    The nuclear waste retrieval system intended to be used for the removal of storage canisters (each canister containing a spent fuel rod assembly) located in an underground salt bed depository is discussed. The implementation of human factors engineering principles during the design and construction of the retrieval system facilities and equipment is reported. The methodology is structured around a basic system development effort involving preliminary development, equipment development, personnel subsystem development, and operational test and evaluation. Examples of application of the techniques in the analysis of human tasks, and equipment required in the removal of spent fuel canisters is provided. The framework for integrating human engineering with the rest of the system development effort is documented.

  18. Evolutionary Computational Method of Facial Expression Analysis for Content-based Video Retrieval using 2-Dimensional Cellular Automata

    CERN Document Server

    Geetha, P

    2010-01-01

    In this paper, Deterministic Cellular Automata (DCA) based video shot classification and retrieval is proposed. The deterministic 2D Cellular automata model captures the human facial expressions, both spontaneous and posed. The determinism stems from the fact that the facial muscle actions are standardized by the encodings of Facial Action Coding System (FACS) and Action Units (AUs). Based on these encodings, we generate the set of evolutionary update rules of the DCA for each facial expression. We consider a Person-Independent Facial Expression Space (PIFES) to analyze the facial expressions based on Partitioned 2D-Cellular Automata which capture the dynamics of facial expressions and classify the shots based on it. Target video shot is retrieved by comparing the similar expression is obtained for the query frame's face with respect to the key faces expressions in the database video. Consecutive key face expressions in the database that are highly similar to the query frame's face, then the key faces are use...

  19. 形状特征的卫星云图检索方法研究%A Method of Satellite Cloud Image Retrieval of Shape Feature

    Institute of Scientific and Technical Information of China (English)

    夏士明; 李骞; 谢凯翔

    2014-01-01

    Satellite cloud image retrieval can help forecasters position similar weather in the past quickly and improve the reliability of the weather forecast. It attempts to use the Zernike moment and grid based method to extract the cloud shape regional characteristics,making similar retrieval for satellite cloud image. The retrieval process is:first of all,carry out the pretreatment of separation on the cloud image, extract the effective characteristics and generate characteristics of the cloud atlas library. Then carry out similarity measurement and simi-larity matching between a given cloud image and the cloud atlas. Finally,output the final result according to the order. By comparing re-trieval results of the two methods,put forward an improved algorithm called grid based inscribed circle method. Experiments show that this method owns the advantages of the above two methods and can retrieve cloud images with similar visual characteristics from the his-tory cloud image atlas.%卫星云图的相似性检索可以帮助预报人员较快地定位历史相似天气状况,提高天气预报的可靠性。文中尝试采用Zernike矩和网格法来提取云图中云的形状区域特征,并对卫星云图进行相似性检索。其过程为:首先对云图进行云地分离的预处理,然后提取云的形状区域特征,并在此基础上生成云图库所对应的特征向量库,接着进行相似度的距离计算和相似性匹配,最后根据距离的排序顺序输出最终的检索结果。通过比较两种方法的检索效果,提出了一种改进的形状特征提取方法-网格内切圆法。实验表明该方法具有以上两种方法的优点,能够得到较好的检索效果,可以有效检索出视觉上相似的云图。

  20. Image retrieval

    DEFF Research Database (Denmark)

    Ørnager, Susanne

    1997-01-01

    The paper touches upon indexing and retrieval for effective searches of digitized images. Different conceptions of what subject indexing means are described as a basis for defining an operational subject indexing strategy for images. The methodology is based on the art historian Erwin Panofsky...... of signs and connotation as meanings relating to feelings or associations. A joint methodology is suggested between the two researchers and the methodology is implemented in analyzing press photos. Fields of application discussed include the messages in an image and the linking between information running...

  1. Image retrieval

    DEFF Research Database (Denmark)

    Ørnager, Susanne

    1997-01-01

    The paper touches upon indexing and retrieval for effective searches of digitized images. Different conceptions of what subject indexing means are described as a basis for defining an operational subject indexing strategy for images. The methodology is based on the art historian Erwin Panofsky......), special knowledge about image codes, and special knowledge about history of ideas. The semiologist Roland Barthes has established a semiology for pictorial expressions based on advertising photos. Barthes uses the concepts denotation/connotation where denotations can be explained as the sober expression...

  2. A high-throughput optomechanical retrieval method for sequence-verified clonal DNA from the NGS platform.

    Science.gov (United States)

    Lee, Howon; Kim, Hyoki; Kim, Sungsik; Ryu, Taehoon; Kim, Hwangbeom; Bang, Duhee; Kwon, Sunghoon

    2015-02-02

    Writing DNA plays a significant role in the fields of synthetic biology, functional genomics and bioengineering. DNA clones on next-generation sequencing (NGS) platforms have the potential to be a rich and cost-effective source of sequence-verified DNAs as a precursor for DNA writing. However, it is still very challenging to retrieve target clonal DNA from high-density NGS platforms. Here we propose an enabling technology called 'Sniper Cloning' that enables the precise mapping of target clone features on NGS platforms and non-contact rapid retrieval of targets for the full utilization of DNA clones. By merging the three cutting-edge technologies of NGS, DNA microarray and our pulse laser retrieval system, Sniper Cloning is a week-long process that produces 5,188 error-free synthetic DNAs in a single run of NGS with a single microarray DNA pool. We believe that this technology has potential as a universal tool for DNA writing in biological sciences.

  3. Exploring Biases of Atmospheric Retrievals in Simulated JWST Transmission Spectra of Hot Jupiters

    CERN Document Server

    Rocchetto, M; Venot, O; Lagage, P -O; Tinetti, G

    2016-01-01

    With a scheduled launch in October 2018, the James Webb Space Telescope (JWST) is expected to revolutionise the field of atmospheric characterization of exoplanets. The broad wavelength coverage and high sensitivity of its instruments will allow us to extract far more information from exoplanet spectra than what has been possible with current observations. In this paper, we investigate whether current retrieval methods will still be valid in the era of JWST, exploring common approximations used when retrieving transmission spectra of hot Jupiters. To assess biases, we use 1D photochemical models to simulate typical hot Jupiter cloud-free atmospheres and generate synthetic observations for a range of carbon-to-oxygen ratios. Then, we retrieve these spectra using TauREx, a Bayesian retrieval tool, using two methodologies: one assuming an isothermal atmosphere, and one assuming a parametrized temperature profile. Both methods assume constant-with-altitude abundances. We found that the isothermal approximation bi...

  4. ABUNDANCE AND BIOMASS ESTIMATES OF COMMERCIAL FISH SPECIES USING HYDRO-ACOUSTIC METHOD IN JAKARTA BAY, INDONESIA

    Directory of Open Access Journals (Sweden)

    Andria Ansri Utama

    2015-06-01

    Full Text Available The Jakarta Bay is known as a fishing ground area for several traditional types of fishing gears. The fishery has important role to provide nutrition, sustainable livelihoods, and poverty alleviation around the area. Abundance estimation of commercial fish species in the Jakarta Bay is essential particularly comparable of series data in order to evaluate the potential changes in distribution and abundance. The purpose of this study is analyzing the distribution of commercial fish species in the Jakarta Bay and estimate their abundance and biomass. Fish assemblages were concentrated in the eastern and central part of bay. Apparently salinity and DO associated with rich density of phytoplankton and zooplankton may explain the spatial variability of short-bodied mackerel and pony fish, while assemblages pattern of spiny hairtail and croaker might be driven by the availability of small planktivorous fish as their diet. The most abundant commercial fish in the Jakarta Bay are Short-bodied mackerel (Rastrelliger brachysoma, Ponyfish (Leiognathus sp., Croaker (Johnius sp. dan Spiny hairtail (Lepturacanthus savala respectively. Furthermore, biomass estimates for those species showed short-bodied mackerel has the highest biomass followed by spiny hairtail, croaker, and ponyfish.

  5. A fast method for the retrieval of integrated longwave and shortwave top-of-atmosphere irradiances from MSG/SEVIRI (RRUMS

    Directory of Open Access Journals (Sweden)

    M. Vázquez-Navarro

    2012-07-01

    Full Text Available A new Rapid Retrieval of upwelling fluxes from MSG/SEVIRI (RRUMS is presented. It has been developed to observe the top-of-atmosphere irradiances of small scale and rapidly changing features that are not sufficiently resolved by specific Earth radiation budget sensors. Our retrieval takes advantage of the spatial and temporal resolution of MSG/SEVIRI and provides outgoing longwave and reflected shortwave radiation only by means of a combination of SEVIRI channels. The longwave retrieval is based on a simple linear combination of brightness temperatures from the SEVIRI infrared channels. Two shortwave retrievals are presented and discussed: the first one based on a multilinear parameterisation and the second one based on a neural network. The neural network method is shown to be slightly more accurate and simpler to apply for the desired purpose. Both LW and SW algorithms have been validated by comparing their results with CERES and GERB irradiance observations. While being less accurate than their dedicated counterparts, the SEVIRI-based methods have two major advantages compared to CERES and GERB: their higher spatial resolution and the better temporal resolution. With our retrievals it is possible to observe the radiative effect of small-scale features such as cumulus clouds, cirrus clouds, or aircraft contrails. The spatial resolution of SEVIRI is 3 km × 3 km in the sub-satellite point, remarkably better than that of CERES (20 km or GERB (45 km. The temporal resolution is 15 min (5 min in the rapid-scan mode, the same as GERB, but significantly better than that of CERES which, being on board of a polar orbiting satellite, has a temporal resolution as low as 2 overpasses per day.

  6. Phase 2, Solid waste retrieval strategy

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.M.

    1994-09-29

    Solid TRU retrieval, Phase 1 is scheduled to commence operation in 1998 at 218W-4C-T01 and complete recovery of the waste containers in 2001. Phase 2 Retrieval will recover the remaining buried TRU waste to be retrieved and provide the preliminary characterization by non-destructive means to allow interim storage until processing for disposal. This document reports on researching the characterization documents to determine the types of wastes to be retrieved and where located, waste configurations, conditions, and required methods for retrieval. Also included are discussions of wastes encompassed by Phase 2 for which there are valid reasons to not retrieve.

  7. 基于颜色/形状直方图的图像检索方法%The Color/Shape Histogram-based Image Retrieval Method

    Institute of Scientific and Technical Information of China (English)

    王晓红; 杨玲

    2003-01-01

    Content-based retrieval technology is widely used in multimedia databases.Some image databases use the color of image as the main retrieving content feature.Shape feature is also used to query image, such as moment variant,rotating angle, etc. In this article, a new approach is presented to retrieve image using the color and shape histogram in-formation. The color/shape-based retrieval technology has the advantages of accelerating the retrieving speed and resisting the image noise.

  8. A new method of trademark image retrieval using PCNN%利用PCNN实现商标图像检索新方法

    Institute of Scientific and Technical Information of China (English)

    朱红伟; 周冬明; 聂仁灿; 赵东风

    2012-01-01

    In order to solve the scaling,rotation and local changes in the trademark image retrieval.A method of trademark retrieval based on pulse coupled neural network(PCNN) model is proposed in this paper.First an effective image preprocessing algorithm,which reduces the influence of trademark gray distribution difference by the trademark color,is presented by combining PCNN image segmentation and the histogram equalization technology.Then the edge time sequence concept,which is used to describe the distribution characteristics of trademark images regional edge in space,is put forward based on PCNN model,and finally achieve the trademark images quickly effective retrieval.We proceed to the computer simulation based on the trademark repository,simulation results show that this method can be entirely accurate to retrieve the corresponding trademark image,so the method has great resistance to color trademark transformation,rotation,local shape changes and good retrieval performance.%为了解决商标存在尺度缩放、角度旋转和区域局部变化后的难以检索的问题,提出了一种基于脉冲耦合神经网络模型(PCNN,Pulsed Coupled Neural Network)的商标检索新方法.首先通过PCNN图像分割和直方图均衡化技术相结合提出了一种有效的图像预处理算法,以减小颜色对于商标灰度分布差异产生的影响.然后在PCNN模型中提出了边缘时间序列概念,并用于提取商标图像的形状特征,最终实现了商标图像的快速有效检索.在所建立的商标库中进行了计算机仿真,仿真结果表明该方法可有效地检索出待检索商标对应的商标图像,可很好地适应商标颜色变化、角度旋转和局部形状变化,体现了较好的检索性能.

  9. Institution Retrieval Methods and Skills in Different Databases%机构检索在不同数据库中的检索方法及技巧

    Institute of Scientific and Technical Information of China (English)

    苗艳荣

    2015-01-01

    机构检索是高校科研管理部门进行科研成果统计的重要手段。由于作者发文时使用的机构名称不规范以及数据库著录规则的不同,给机构检索带来很大困难。文章介绍了机构检索通常会选取的国内外著名检索工具,并结合实际经验实例演示机构检索在不同数据库中的检索方法及技巧,提出规范机构名称和地址及其英文翻译,准确掌握不同数据库的著录格式,并与委托单位建立协作方式等建议。%Institution retrieval is an important means of scientific achievement statistics for scientific research management department in colleges and universities. Due to the de - normalization of institution name and the differences of rules of database description used by writers,great difficulties always happen on institution retrieval. This article introduces the usual famous retrieval tools at home and abroad and demonstrates the methods and skills in different databases combining practical experience in institution retrieval. Standardi-zing institution name,address and its English translation,description form and format of different databases,elaborating collaborative approaches with client are proposed in this article. 7 refs.

  10. Exploring Biases of Atmospheric Retrievals in Simulated JWST Transmission Spectra of Hot Jupiters

    Science.gov (United States)

    Rocchetto, M.; Waldmann, I. P.; Venot, O.; Lagage, P.-O.; Tinetti, G.

    2016-12-01

    With a scheduled launch in 2018 October, the James Webb Space Telescope (JWST) is expected to revolutionize the field of atmospheric characterization of exoplanets. The broad wavelength coverage and high sensitivity of its instruments will allow us to extract far more information from exoplanet spectra than what has been possible with current observations. In this paper, we investigate whether current retrieval methods will still be valid in the era of JWST, exploring common approximations used when retrieving transmission spectra of hot Jupiters. To assess biases, we use 1D photochemical models to simulate typical hot Jupiter cloud-free atmospheres and generate synthetic observations for a range of carbon-to-oxygen ratios. Then, we retrieve these spectra using TauREx, a Bayesian retrieval tool, using two methodologies: one assuming an isothermal atmosphere, and one assuming a parameterized temperature profile. Both methods assume constant-with-altitude abundances. We found that the isothermal approximation biases the retrieved parameters considerably, overestimating the abundances by about one order of magnitude. The retrieved abundances using the parameterized profile are usually within 1σ of the true state, and we found the retrieved uncertainties to be generally larger compared to the isothermal approximation. Interestingly, we found that by using the parameterized temperature profile we could place tight constraints on the temperature structure. This opens the possibility of characterizing the temperature profile of the terminator region of hot Jupiters. Lastly, we found that assuming a constant-with-altitude mixing ratio profile is a good approximation for most of the atmospheres under study.

  11. Standard test method for isotopic abundance analysis of uranium hexafluoride and uranyl nitrate solutions by multi-collector, inductively coupled plasma-mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2014-01-01

    1.1 This test method covers the isotopic abundance analysis of 234U, 235U, 236U and 238U in samples of hydrolysed uranium hexafluoride (UF6) by inductively coupled plasma source, multicollector, mass spectrometry (ICP-MC-MS). The method applies to material with 235U abundance in the range of 0.2 to 6 % mass. This test method is also described in ASTM STP 1344. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  12. Ontology-based Information Retrieval

    DEFF Research Database (Denmark)

    Styltsvig, Henrik Bulskov

    of concept similarity in query evaluation is discussed. A semantic expansion approach that incorporates concept similarity is introduced and a generalized fuzzy set retrieval model that applies expansion during query evaluation is presented. While not commonly used in present information retrieval systems......In this thesis, we will present methods for introducing ontologies in information retrieval. The main hypothesis is that the inclusion of conceptual knowledge such as ontologies in the information retrieval process can contribute to the solution of major problems currently found in information...... retrieval. This utilization of ontologies has a number of challenges. Our focus is on the use of similarity measures derived from the knowledge about relations between concepts in ontologies, the recognition of semantic information in texts and the mapping of this knowledge into the ontologies in use...

  13. New Methods for Retrieval of Chlorophyll Red Fluorescence from Hyperspectral Satellite Instruments: Simulations and Application to GOME-2 and SCIAMACHY

    Science.gov (United States)

    Joiner, Joanna; Yoshida, Yasuko; Guanter, Luis; Middleton, Elizabeth M.

    2016-01-01

    Global satellite measurements of solar-induced fluorescence (SIF) from chlorophyll over land and ocean have proven useful for a number of different applications related to physiology, phenology, and productivity of plants and phytoplankton. Terrestrial chlorophyll fluorescence is emitted throughout the red and far-red spectrum, producing two broad peaks near 683 and 736nm. From ocean surfaces, phytoplankton fluorescence emissions are entirely from the red region (683nm peak). Studies using satellite-derived SIF over land have focused almost exclusively on measurements in the far red (wavelengths greater than 712nm), since those are the most easily obtained with existing instrumentation. Here, we examine new ways to use existing hyperspectral satellite data sets to retrieve red SIF (wavelengths less than 712nm) over both land and ocean. Red SIF is thought to provide complementary information to that from the far red for terrestrial vegetation. The satellite instruments that we use were designed to make atmospheric trace-gas measurements and are therefore not optimal for observing SIF; they have coarse spatial resolution and only moderate spectral resolution (0.5nm). Nevertheless, these instruments, the Global Ozone Monitoring Instrument 2 (GOME-2) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY), offer a unique opportunity to compare red and far-red terrestrial SIF at regional spatial scales. Terrestrial SIF has been estimated with ground-, aircraft-, or satellite-based instruments by measuring the filling-in of atmospheric andor solar absorption spectral features by SIF. Our approach makes use of the oxygen (O2) gamma band that is not affected by SIF. The SIF-free O2 gamma band helps to estimate absorption within the spectrally variable O2 B band, which is filled in by red SIF. SIF also fills in the spectrally stable solar Fraunhofer lines (SFLs) at wavelengths both inside and just outside the O2 B band, which further helps

  14. Evaluation of Methods for Aerodynamic Roughness Length Retrieval from Very High-Resolution Imaging LIDAR Observations over the Heihe Basin in China

    Directory of Open Access Journals (Sweden)

    Robin Faivre

    2017-01-01

    Full Text Available The parameterization of heat transfer based on remote sensing data, and the Surface Energy Balance System (SEBS scheme to retrieve turbulent heat fluxes, already proved to be very appropriate for estimating evapotranspiration (ET over homogeneous land surfaces. However, the use of such a method over heterogeneous landscapes (e.g., semi-arid regions or agricultural land becomes more difficult, since the principle of similarity theory is compromised by the presence of different heat sources at various heights. This study aims to propose and evaluate some models based on vegetation geometry partly developed by Colin and Faivre, to retrieve the surface aerodynamic roughness length for momentum transfer ( z 0 m , which is a key parameter in the characterization of heat transfer. A new approach proposed by the authors consisted in the use of a Digital Surface Model (DSM as boundary condition for experiments with a Computational Fluid Dynamics (CFD model to reproduce 3D wind fields, and to invert them to retrieve a spatialized roughness parameter. Colin and Faivre also applied the geometrical Raupach’s approach for the same purpose. These two methods were evaluated against two empirical ones, widely used in Surface Energy Balance Index (SEBI based algorithms (Moran; Brutsaert, and also against an alternate geometrical model proposed by Menenti and Ritchie. The investigation was carried out in the Yingke oasis (China using very-high resolution remote sensing data (VNIR, TIR & LIDAR, for a precise description of the land surface, and a fine evaluation of estimated heat fluxes based on in-situ measurements. A set of five numerical experiments was carried out to evaluate each roughness model. It appears that methods used in experiments 2 (based on Brutsaert and 4 (based on Colin and Faivre are the most accurate to estimate the aerodynamic roughness length, according to the estimated heat fluxes. However, the formulation used in experiment 2 allows to

  15. Interactive Exploration for Image Retrieval

    Directory of Open Access Journals (Sweden)

    Jérôme Fournier

    2005-08-01

    Full Text Available We present a new version of our content-based image retrieval system RETIN. It is based on adaptive quantization of the color space, together with new features aiming at representing the spatial relationship between colors. Color analysis is also extended to texture. Using these powerful indexes, an original interactive retrieval strategy is introduced. The process is based on two steps for handling the retrieval of very large image categories. First, a controlled exploration method of the database is presented. Second, a relevance feedback method based on statistical learning is proposed. All the steps are evaluated by experiments on a generalist database.

  16. 基于特征的二值商标分层检索方法%A Hierarchical Binary Trademark Retrieval Method Based on Feature

    Institute of Scientific and Technical Information of China (English)

    褚菁菁; 张吉楠

    2011-01-01

    针对以往商标图像搜索方法单一,并且缺少用户反馈的缺点,文中提出一种基于形状特征和纹理特征的二值商标图像分层搜索方法.该方法首先利用HU不变矩提取图像的形状特征;然后利用欧氏距离来测量图像的相似度,进行第一次筛选得到一个数目不定的候选集;接着利用灰度直方图的方法提取候选集中的图像的纹理信息,进行第二次筛选;最后通过用户的反馈进行不断的优化.从而使检索出来的图像更加迅速和准确,更加符合人的视觉感受.%The previous binary trademark image retrieval method is not perfect for lack of comprehensive approach and user feedback.This paper presents a hierarchical binary trademark image retrieval method based on shape and texture features. Firstly, this method uses Hu invariant moments shape feature to extract the images and then uses Euclidean distance to measure the image similarity, and filter a number of uncertainties in the candidate set; then extracts gray level histogram of the image the candidate focused on texture information,and get a second filter; Finally, it is optimized by continuous user feedback. This binary trademark images retrieval mothed is more quickly, accurately, and more in line with human perception.

  17. Retrieval of specimens in laparoscopy using reclosable zipper-type plastic bags: a simple, cheap, and useful method.

    Science.gov (United States)

    Weber, A; Vázquez, J A; Valencia, S; Cueto, J

    1998-12-01

    Surgical specimens must often be extracted during laparoscopic surgery. Although the technologic advances in this field are amazing, simple measures may sometimes work even better than very sophisticated instruments. This is true of the reclosable plastic bags with zipper-type closure that we use for retrieving surgical specimens from the abdominal cavity in order to protect it as well as the abdominal wall. The bags are cheap, offer no problems for sterilization, are easy to obtain, and are available in many sizes. They are very simple to handle, making it easy to slip in the specimen and then extract it from the abdominal cavity. We describe our experience with these bags and a technique for manipulating them.

  18. Retrieval of tropospheric NO2 using the MAX-DOAS method combined with relative intensity measurements for aerosol correction

    Directory of Open Access Journals (Sweden)

    P. F. Levelt

    2010-10-01

    Full Text Available Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS is a technique to measure trace gas amounts in the lower troposphere from ground-based scattered sunlight observations. MAX-DOAS observations are especially suitable for validation of tropospheric trace gas observations from satellite, since they have a representative range of several kilometers, both in the horizontal and in the vertical dimension. A two-step retrieval scheme is presented here, to derive aerosol corrected tropospheric NO2 columns from MAX-DOAS observations. In a first step, boundary layer aerosols, characterized in terms of aerosol optical thickness (AOT, are estimated from relative intensity observations, which are defined as the ratio of the sky radiance at elevation α and the sky radiance in the zenith. Relative intensity measurements have the advantage of a strong dependence on boundary layer AOT and almost no dependence on boundary layer height. In a second step, tropospheric NO2 columns are derived from differential slant columns, based on AOT-dependent air mass factors. This two-step retrieval scheme was applied to cloud free periods in a twelve month data set of observations in De Bilt, The Netherlands. In a comparison with AERONET (Cabauw site a mean difference in AOT (AERONET minus MAX-DOAS of −0.01±0.08 was found, and a correlation of 0.85. Tropospheric-NO2 columns were compared with OMI-satellite tropospheric NO2. For ground-based observations restricted to uncertainties below 10%, no significant difference was found, and a correlation of 0.88.

  19. Evaluating the Utility of Satellite Soil Moisture Retrievals over Irrigated Areas and the Ability of Land Data Assimilation Methods to Correct for Unmodeled Processes

    Science.gov (United States)

    Kumar, S. V.; Peters-Lidard, C. D.; Santanello, J. A.; Reichle, R. H.; Draper, C. S.; Koster, R. D.; Nearing, G.; Jasinski, M. F.

    2015-01-01

    Earth's land surface is characterized by tremendous natural heterogeneity and human-engineered modifications, both of which are challenging to represent in land surface models. Satellite remote sensing is often the most practical and effective method to observe the land surface over large geographical areas. Agricultural irrigation is an important human-induced modification to natural land surface processes, as it is pervasive across the world and because of its significant influence on the regional and global water budgets. In this article, irrigation is used as an example of a human-engineered, often unmodeled land surface process, and the utility of satellite soil moisture retrievals over irrigated areas in the continental US is examined. Such retrievals are based on passive or active microwave observations from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E), the Advanced Microwave Scanning Radiometer 2 (AMSR2), the Soil Moisture Ocean Salinity (SMOS) mission, WindSat and the Advanced Scatterometer (ASCAT). The analysis suggests that the skill of these retrievals for representing irrigation effects is mixed, with ASCAT-based products somewhat more skillful than SMOS and AMSR2 products. The article then examines the suitability of typical bias correction strategies in current land data assimilation systems when unmodeled processes dominate the bias between the model and the observations. Using a suite of synthetic experiments that includes bias correction strategies such as quantile mapping and trained forward modeling, it is demonstrated that the bias correction practices lead to the exclusion of the signals from unmodeled processes, if these processes are the major source of the biases. It is further shown that new methods are needed to preserve the observational information about unmodeled processes during data assimilation.

  20. Evaluating the utility of satellite soil moisture retrievals over irrigated areas and the ability of land data assimilation methods to correct for unmodeled processes

    Science.gov (United States)

    Kumar, S. V.; Peters-Lidard, C. D.; Santanello, J. A.; Reichle, R. H.; Draper, C. S.; Koster, R. D.; Nearing, G.; Jasinski, M. F.

    2015-11-01

    Earth's land surface is characterized by tremendous natural heterogeneity and human-engineered modifications, both of which are challenging to represent in land surface models. Satellite remote sensing is often the most practical and effective method to observe the land surface over large geographical areas. Agricultural irrigation is an important human-induced modification to natural land surface processes, as it is pervasive across the world and because of its significant influence on the regional and global water budgets. In this article, irrigation is used as an example of a human-engineered, often unmodeled land surface process, and the utility of satellite soil moisture retrievals over irrigated areas in the continental US is examined. Such retrievals are based on passive or active microwave observations from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E), the Advanced Microwave Scanning Radiometer 2 (AMSR2), the Soil Moisture Ocean Salinity (SMOS) mission, WindSat and the Advanced Scatterometer (ASCAT). The analysis suggests that the skill of these retrievals for representing irrigation effects is mixed, with ASCAT-based products somewhat more skillful than SMOS and AMSR2 products. The article then examines the suitability of typical bias correction strategies in current land data assimilation systems when unmodeled processes dominate the bias between the model and the observations. Using a suite of synthetic experiments that includes bias correction strategies such as quantile mapping and trained forward modeling, it is demonstrated that the bias correction practices lead to the exclusion of the signals from unmodeled processes, if these processes are the major source of the biases. It is further shown that new methods are needed to preserve the observational information about unmodeled processes during data assimilation.

  1. Introduction to information retrieval

    CERN Document Server

    Manning, Christopher D; Schütze, Hinrich

    2008-01-01

    Class-tested and coherent, this textbook teaches classical and web information retrieval, including web search and the related areas of text classification and text clustering from basic concepts. It gives an up-to-date treatment of all aspects of the design and implementation of systems for gathering, indexing, and searching documents; methods for evaluating systems; and an introduction to the use of machine learning methods on text collections. All the important ideas are explained using examples and figures, making it perfect for introductory courses in information retrieval for advanced undergraduates and graduate students in computer science. Based on feedback from extensive classroom experience, the book has been carefully structured in order to make teaching more natural and effective. Slides and additional exercises (with solutions for lecturers) are also available through the book's supporting website to help course instructors prepare their lectures.

  2. Registration Based Retrieval using Texture Measures

    Directory of Open Access Journals (Sweden)

    Swarnambiga AYYACHAMY

    2015-09-01

    Full Text Available The aim of the study presented in this manuscript was to develop and analyze registration based retrieval of medical image using texture measures. Three main methods are implemented in this work. The first method includes Affine transformation, Demons and Affine with B-spline. The second method implemented is medical image retrieval system using content based medical image retrieval. GLCM, LBP and GLCM with LBP are used for texture based retrieval. Shape based retrieval is processed using canny edge with the Otsu method. From registration based retrieval, Affine with B-Spline performs well and produces best result by increasing the retrieval rate and the next better performances are given by Demons and Affine registration. The results showed that the best results for registration based retrieval are given by Affine with B-Spline registration based retrieval using GLCM+LBP with (100/50. Based on more relevant retrieved images, Brain (100/50 and Knee (100/50 observed to have more relevant retrieved images.

  3. A Framework Based on 2-D Taylor Expansion for Quantifying the Impacts of Subpixel Reflectance Variance and Covariance on Cloud Optical Thickness and Effective Radius Retrievals Based on the Bispectral Method

    Science.gov (United States)

    Zhang, Z.; Werner, F.; Cho, H.-M.; Wind, G.; Platnick, S.; Ackerman, A. S.; Di Girolamo, L.; Marshak, A.; Meyer, K.

    2016-01-01

    The bispectral method retrieves cloud optical thickness (t) and cloud droplet effective radius (re) simultaneously from a pair of cloud reflectance observations, one in a visible or near-infrared (VIS/NIR) band and the other in a shortwave infrared (SWIR) band. A cloudy pixel is usually assumed to be horizontally homogeneous in the retrieval. Ignoring subpixel variations of cloud reflectances can lead to a significant bias in the retrieved t and re. In the literature, the retrievals of t and re are often assumed to be independent and considered separately when investigating the impact of subpixel cloud reflectance variations on the bispectral method. As a result, the impact on t is contributed only by the subpixel variation of VIS/NIR band reflectance and the impact on re only by the subpixel variation of SWIR band reflectance. In our new framework, we use the Taylor expansion of a two-variable function to understand and quantify the impacts of subpixel variances of VIS/NIR and SWIR cloud reflectances and their covariance on the t and re retrievals. This framework takes into account the fact that the retrievals are determined by both VIS/NIR and SWIR band observations in a mutually dependent way. In comparison with previous studies, it provides a more comprehensive understanding of how subpixel cloud reflectance variations impact the t and re retrievals based on the bispectral method. In particular, our framework provides a mathematical explanation of how the subpixel variation in VIS/NIR band influences the re retrieval and why it can sometimes outweigh the influence of variations in the SWIR band and dominate the error in re retrievals, leading to a potential contribution of positive bias to the re retrieval. We test our framework using synthetic cloud fields from a large-eddy simulation and real observations from Moderate Resolution Imaging Spectroradiometer. The predicted results based on our framework agree very well with the numerical simulations. Our

  4. Characterisation of GOME-2 formaldehyde retrieval sensitivity

    Directory of Open Access Journals (Sweden)

    W. Hewson

    2012-09-01

    Full Text Available Formaldehyde (HCHO is an important tracer of tropospheric photochemistry, whose slant column abundance can be retrieved from satellite measurements of solar backscattered UV radiation, using differential absorption retrieval techniques. In this work a spectral fitting sensitivity analysis is conducted on HCHO slant columns retrieved from the Global Ozone Monitoring Experiment 2 (GOME-2 instrument. Despite quite different spectral fitting approaches, the retrieved HCHO slant columns have geographic distributions that generally match expected HCHO sources, though the slant column magnitudes and corresponding uncertainties are particularly sensitive to the retrieval set-up. The choice of spectral fitting window, polynomial order, I0 correction, and inclusion of minor absorbers tend to have the largest impact on the fit residuals. However, application of a reference sector correction using observations over the remote Pacific Ocean, is shown to largely homogenise the resulting HCHO vertical columns, thereby largely reducing any systematic erroneous spectral fitting.

  5. Practical quantum retrieval games

    Science.gov (United States)

    Arrazola, Juan Miguel; Karasamanis, Markos; Lütkenhaus, Norbert

    2016-06-01

    Complex cryptographic protocols are often constructed from simpler building blocks. In order to advance quantum cryptography, it is important to study practical building blocks that can be used to develop new protocols. An example is quantum retrieval games (QRGs), which have broad applicability and have already been used to construct quantum money schemes. In this work, we introduce a general construction of quantum retrieval games based on the hidden matching problem and show how they can be implemented in practice using available technology. More precisely, we provide a general method to construct (1-out-of-k ) QRGs, proving that their cheating probabilities decrease exponentially in k . In particular, we define QRGs based on coherent states of light, which can be implemented even in the presence of experimental imperfections. Our results constitute a tool in the arsenal of the practical quantum cryptographer.

  6. Interactive Information Retrieval:

    DEFF Research Database (Denmark)

    Borlund, Pia

    This presentation addresses methodological issues of interactive information retrieval (IIR) evaluation in terms of what it entails to study users' use and interaction with IR systems, as well as their satisfaction with retrieved information. In particular, the presentation focuses on test design......, and it takes a look into the toolbox of IIR test design with reference to data collection methods and test procedure. It calls for careful and well-planned studies to qualify the knowledgebase generated as a result of the conducted IIR studies. The presentation further reflects on the need for an updated...... IIR from the perspective of search dedication and task load in order to also include everyday life information seeking? With this presentation, the IIR community is invited to an exchange of ideas and is encouraged to engage in collaborations with the solving of these (and other) issues to our joint...

  7. Estimation of biological nitrogen fixation by black locust in short-rotation forests using natural 15N abundance method

    Science.gov (United States)

    Veste, M.; Böhm, C.; Quinckenstein, A.; Freese, D.

    2012-04-01

    The importance of short rotation forests and agroforestry systems for woody biomass production for bioenergy will increase in Central Europe within the next decades. In this context, black locust (Robinia pseudoacacia) has a high growth potential especially at marginal, drought-susceptible sites such as occur in Brandenburg State (Eastern Germany). As a pioneer tree species black locust grows under a wide range of site conditions. The native range of black locust in Northern America is classified by a humid to sub-humid climate with a mean annual precipitation of 1020 to 1830 mm. In Central and Eastern Europe, this species is cultivated in a more continental climate with an annual precipitation often below 600 mm. Therefore, black locust is known to be relatively drought tolerant compared to other temperate, deciduous tree species. Because of its N2-fixation ability black locust plays generally an important role for the improvement of soil fertility. This effect is of particular interest at marginal sites in the post-mining landscapes. In order to estimate the N2-fixation potential of black locust at marginal sites leaf samples were taken from black locust trees in short rotation plantations planted between 1995 and 2007 in post-mining sites south of Cottbus (Brandenburg, NE Germany). The variation of the natural 15N abundance was measured to evaluate the biological nitrogen fixation. The nitrogen derived from the atmosphere can be calculated using a two-pool model from the quotient of the natural 15N abundances of the N2-fixing plant and the plant available soil N. Because representatively determining the plant available soil N is difficult, a non-N2-fixing reference plant growing at the same site with a similar root system and temporal N uptake pattern to the N2-fixing plant is often used. In our case we used red oak (Quercus rubra) as a reference. The average nitrogen content in the leaves of black locust ranged from 3.1% (C/N 14.8) in 15 years old trees to 3

  8. Invasive brain-machine interfaces: a survey of paralyzed patients’ attitudes, knowledge and methods of information retrieval

    Science.gov (United States)

    Lahr, Jacob; Schwartz, Christina; Heimbach, Bernhard; Aertsen, Ad; Rickert, Jörn; Ball, Tonio

    2015-08-01

    Objective. Brain-machine interfaces (BMI) are an emerging therapeutic option that can allow paralyzed patients to gain control over assistive technology devices (ATDs). BMI approaches can be broadly classified into invasive (based on intracranially implanted electrodes) and noninvasive (based on skin electrodes or extracorporeal sensors). Invasive BMIs have a favorable signal-to-noise ratio, and thus allow for the extraction of more information than noninvasive BMIs, but they are also associated with the risks related to neurosurgical device implantation. Current noninvasive BMI approaches are typically concerned, among other issues, with long setup times and/or intensive training. Recent studies have investigated the attitudes of paralyzed patients eligible for BMIs, particularly patients affected by amyotrophic lateral sclerosis (ALS). These studies indicate that paralyzed patients are indeed interested in BMIs. Little is known, however, about the degree of knowledge among paralyzed patients concerning BMI approaches or about how patients retrieve information on ATDs. Furthermore, it is not yet clear if paralyzed patients would accept intracranial implantation of BMI electrodes with the premise of decoding improvements, and what the attitudes of a broader range of patients with diseases such as stroke or spinal cord injury are towards this new kind of treatment. Approach. Using a questionnaire, we surveyed 131 paralyzed patients for their opinions on invasive BMIs and their attitude toward invasive BMI treatment options. Main results. The majority of the patients knew about and had a positive attitude toward invasive BMI approaches. The group of ALS patients was especially open to the concept of BMIs. The acceptance of invasive BMI technology depended on the improvements expected from the technology. Furthermore, the survey revealed that for paralyzed patients, the Internet is an important source of information on ATDs. Significance. Websites tailored to

  9. The MOSDEF Survey: Detection of [OIII]$\\lambda$4363 and the direct-method oxygen abundance of a star-forming galaxy at z=3.08

    CERN Document Server

    Sanders, Ryan L; Kriek, Mariska; Reddy, Naveen A; Freeman, William R; Coil, Alison L; Siana, Brian; Mobasher, Bahram; Shivaei, Irene; Price, Sedona H; de Groot, Laura

    2016-01-01

    We present measurements of the electron-temperature based oxygen abundance for a highly star-forming galaxy at z=3.08, COSMOS-1908. This is the highest redshift at which [OIII]$\\lambda$4363 has been detected, and the first time that this line has been measured at z>2. We estimate an oxygen abundance of 12+log(O/H)$=8.00^{+0.13}_{-0.14}$. This galaxy is a low-mass ($10^{9.3}$ M$_{\\odot}$), highly star-forming ($\\sim50$ M$_{\\odot}$ yr$^{-1}$) system that hosts a young stellar population ($\\sim160$ Myr). We investigate the physical conditions of the ionized gas in COSMOS-1908 and find that this galaxy has a high ionization parameter, little nebular reddening ($E(B-V)_{\\rm gas}<0.14$), and a high electron density ($n_e\\sim500$ cm$^{-3}$). We compare the ratios of strong oxygen, neon, and hydrogen lines to the direct-method oxygen abundance for COSMOS-1908 and additional star-forming galaxies at z=0-1.8 with [OIII]$\\lambda$4363 measurements, and show that galaxies at z$\\sim$1-3 follow the same strong-line corre...

  10. Method of Information Retrieval Based on Rough Ontology%一种基于Rough本体的信息检索方法

    Institute of Scientific and Technical Information of China (English)

    胡军; 陈传明

    2011-01-01

    基于本体的信息检索是实现知识检索的有效途径,针对目前本体支持的形式化概念还不足以表示不完备知识的问题,提出一种基于Rough本体的信息检索方法,该方法中本体以本体信息系统的形式表示.用户提交关键字查询后,首先结合基于关键字检索的方法在预先定义的语义文档空间中搜索文档,然后利用关联搜索的方法来搜索与关键词关联的个体集和属性集,以属性集作为等价类构造Rough本体的近似空间,最后通过近似空间计算个体集和文档集的相似度,根据相似度高低对文档排序.实验表明,此方法比基于关键字和基于经典本体的方法有更高的查准率.%Information retrieval based on ontology is an effective approach to achieve knowledge retrieval. A kind of information retrieval methodology based on rough ontology is proposed against formal concept, which is supported by ontology, is not enough to represent incomplete knowledge. This methodology represents ontology in the form of ontology information system. First, given a keyword based query, it combines with the keyword based method to search documents in predefined semantic document space, and then, association search method is used to search individual set and property set relating to query keywords, and property set as equivalence class constructs approximation space. Last, approximation space is used to compute similarity of individual set and document set and according to the degree of similarity to rank. The experiment shows that this methodology can be performed more better than methods based on keyword and classical ontology in precision.

  11. Automated Medical Literature Retrieval

    Directory of Open Access Journals (Sweden)

    David Hawking

    2012-09-01

    Full Text Available Background The constantly growing publication rate of medical research articles puts increasing pressure on medical specialists who need to be aware of the recent developments in their field. The currently used literature retrieval systems allow researchers to find specific papers; however the search task is still repetitive and time-consuming. Aims In this paper we describe a system that retrieves medical publications by automatically generating queries based on data from an electronic patient record. This allows the doctor to focus on medical issues and provide an improved service to the patient, with higher confidence that it is underpinned by current research. Method Our research prototype automatically generates query terms based on the patient record and adds weight factors for each term. Currently the patient’s age is taken into account with a fuzzy logic derived weight, and terms describing blood-related anomalies are derived from recent blood test results. Conditionally selected homonyms are used for query expansion. The query retrieves matching records from a local index of PubMed publications and displays results in descending relevance for the given patient. Recent publications are clearly highlighted for instant recognition by the researcher. Results Nine medical specialists from the Royal Adelaide Hospital evaluated the system and submitted pre-trial and post-trial questionnaires. Throughout the study we received positive feedback as doctors felt the support provided by the prototype was useful, and which they would like to use in their daily routine. Conclusion By supporting the time-consuming task of query formulation and iterative modification as well as by presenting the search results in order of relevance for the specific patient, literature retrieval becomes part of the daily workflow of busy professionals.

  12. Harmonizing methods for wildlife abundance estimation and pathogen detection in Europe-a questionnaire survey on three selected host-pathogen combinations

    DEFF Research Database (Denmark)

    Schulz, Jana; Ryser-Degiorgis, Marie-Pierre; Kuiken, Thijs

    2017-01-01

    , resulting in a patchwork of data that are difficult to merge and compare. This survey aimed at evaluating the need and potential for data harmonization in wildlife health in Europe. The specific objective was to collect information on methods currently used to estimate host abundance and pathogen prevalence....... For small rodents, trapping is the method of choice, but practical applications vary among study sites. Laboratory procedures are already largely harmonized but information on the sampled animals is not systematically collected.Conclusions: The answers revealed that a large amount of information...... is available for the selected host-pathogen pairs and that in theory methods are already largely harmonized. However, the comparability of the data remains strongly compromised by local differences in the way, the methods are applied in practice. While these issues may easily be overcome for prevalence...

  13. Surgical Sperm Retrieval: Which Method to Use?%外科取精术: 选择哪种方法?

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    在过去的5~10年里,医学领域中很少有像生殖医学那样发展迅速,特别是使用卵胞浆内精子注射(ICSI)技术治疗男性不育及先进的外科附睾和睾丸取精术.这两项重大技术进步彻底改变了原先不可治愈的睾丸衰竭(非梗阻性无精子症)、射精障碍或不可修复的梗阻性无精子症.那些患有非常严重的不能用特殊方法和手术治疗的不育男性,现在有机会利用他们仅有的几条精子做起其生物学子女的父亲.讨论了辅助生育的各种先进的精子取出术,重点讨论技术和安全性.每一技术有其特殊的医学适应证、功效和局限性.%During the past 5~10 years, very few medical fields have changeddramatically as reproductive medicine, especially for the new treatment for the maleinfertility by the use of intracytoplasmic sperm injection (ICSI) techniques andadvanced surgical epididymal and testicular sperm retrieval techniques. Those twomajor technical advances have completely changed the treatment for previouslyuntreatable testicular failure (non-obstructive azoospermia), ejaculatory failure orun-reconstructable obstructive azoospermia. Many men with even the most severe formsof infertility that are not amendable to specific medical and surgical treatmentscan now have chances to father biological children with only a few of theirspermatozoa. This review serves to discuss the various advanced sperm retrievaltechniques available for assisted reproduction, with specific focus on the technicalaspects and safety. Each technique has its specific medical indications, efficacies

  14. Comparison of two methods for estimating the abundance, diversity and habitat preference of fluvial macroinvertebrates in contrasting habitats

    NARCIS (Netherlands)

    Alonso, A.; Camargo, J.A.

    2010-01-01

    In this research we evaluate the effects of the method used for estimating the potential surface available for benthic macroinvertebrates in macrophyte and unvegetated habitats on several metrics and habitat preference of aquatic macroinvertebrates in the upper catchment of the Henares River (Guadal

  15. Energy fluxes retrieval on an Alaskan Arctic and Sub-Arctic vegetation by means MODIS imagery and the DTD method

    Science.gov (United States)

    Cristobal, J.; Prakash, A.; Starkenburg, D. P.; Fochesatto, G. J.; Anderson, M. C.; Gens, R.; Kane, D. L.; Kustas, W.; Alfieri, J. G.

    2012-12-01

    Evapotranspiration (ET) plays a significant role in the hydrologic cycle of Arctic and Sub-Arctic basins. Surface-atmosphere exchanges due to ET are estimated from water balance computations to be about 74% of summer precipitation or 50% of annual precipitation. Even though ET is a significant component of the hydrologic cycle in this region, the bulk estimates don't accurately account for spatial and temporal variability due to vegetation type, topography, etc. (Kane and Yang, 2004). Nowadays, remote sensing is the only technology capable of providing the necessary radiometric measurements for the calculation of the ET at global scales and in a feasible economic way, especially in Arctic and Sub-Arctic Alaskan basins with a very sparse network of both meteorological and flux towers. In this work we present the implementation and validation of the Dual-Time-Difference model (Kustas et al., 2001) to retrieve energy fluxes (ET, sensible heat flux, net radiation and soil heat flux) in tundra vegetation in Arctic conditions and in a black spruce (Picea mariana) forest in Sub-Arctic conditions. In order to validate the model in tundra vegetation we used a flux tower from the Imnavait Creek sites of the Arctic Observatory Network (Euskirchen et al. 2012). In the case of the black spruce forest, on September 2011 we installed a flux tower in the University of Alaska Fairbanks north campus that includes an eddy-covariance system as well a net radiometer, air temperature probes, soil heat flux plates, soil moisture sensors and thermistors to fully estimate energy fluxes in the field (see http://www.et.alaska.edu/ for further details). Additionally, in order to upscale energy fluxes into MODIS spatial resolution, a scintillometer was also installed covering 1.2 km across the flux tower. DTD model mainly requires meteorological inputs as well as land surface temperature (LST) and leaf area index (LAI) data, both coming from satellite imagery, at two different times: after

  16. Evolution of N/O Abundance Ratios and Ionization Parameters from z~0 to 2 Investigated by the Direct Temperature Method

    CERN Document Server

    Kojima, Takashi; Nakajima, Kimihiko; Shibuya, Takatoshi; Harikane, Yuichi; Ono, Yoshiaki

    2016-01-01

    We present N/O abundance ratios, ionization parameters $q_{\\rm ion}$, and oxygen abundance O/H of eleven $z\\sim 2$ galaxies determined by the direct temperature $T_{\\rm e}$ method with [OIII] $\\lambda$4363 and OIII] $\\lambda$1665 lines, and investigate galaxy evolution from $z\\sim 0$ to $2$ in conjunction with $T_{\\rm e}$-method measurements of 208,529 SDSS galaxies and 9 green pea galaxies (GPs). We identify that three out of our eleven $z\\sim 2$ galaxies clearly fall beyond the local average of N/O-O/H and N/O-stellar mass ($M_{\\star}$) relations, while the rest of the $z\\sim 2$ galaxies have N/O ratios comparable with $z\\sim 0$ galaxies. The eleven $z\\sim 2$ galaxies place the upper limit of N/O ratio $\\log ({\\rm N/O})\\le -1.28$ on average, suggesting that the N/O ratio evolves, if any, by $<0.15$ dex. We find that two of our $z\\sim 2$ galaxies with the significant BPT offsets show both N/O ratio and $q_{\\rm ion}$ about 0.4-dex higher than the local average, while there exist $z\\sim 0$ green-pea galaxie...

  17. Bacteria abundance and diversity of different life stages of Plutella xylostella (Lepidoptera: Plutellidae), revealed by bacteria culture-dependent and PCR-DGGE methods.

    Science.gov (United States)

    Lin, Xiao-Li; Pan, Qin-Jian; Tian, Hong-Gang; Douglas, Angela E; Liu, Tong-Xian

    2015-03-01

    Microbial abundance and diversity of different life stages (fourth instar larvae, pupae and adults) of the diamondback moth, Plutella xylostella L., collected from field and reared in laboratory, were investigated using bacteria culture-dependent method and PCR-DGGE analysis based on the sequence of bacteria 16S rRNA V3 region gene. A large quantity of bacteria was found in all life stages of P. xylostella. Field population had higher quantity of bacteria than laboratory population, and larval gut had higher quantity than pupae and adults. Culturable bacteria differed in different life stages of P. xylostella. Twenty-five different bacterial strains were identified in total, among them 20 strains were presented in larval gut, only 8 strains in pupae and 14 strains in adults were detected. Firmicutes bacteria, Bacillus sp., were the most dominant species in every life stage. 15 distinct bands were obtained from DGGE electrophoresis gel. The sequences blasted in GenBank database showed these bacteria belonged to six different genera. Phylogenetic analysis showed the sequences of the bacteria belonged to the Actinobacteri, Proteobacteria and Firmicutes. Serratia sp. in Proteobacteria was the most abundant species in larval gut. In pupae, unculturable bacteria were the most dominant species, and unculturable bacteria and Serratia sp. were the most dominant species in adults. Our study suggested that a combination of molecular and traditional culturing methods can be effectively used to analyze and to determine the diversity of gut microflora. These known bacteria may play important roles in development of P. xylostella.

  18. Report and recommendations of the international workshop "Retrieval approaches for information on alternative methods to animal experiments".

    Science.gov (United States)

    Grune, Barbara; Fallon, Michael; Howard, Carol; Hudson, Vera; Kulpa-Eddy, Jodie A; Larson, Jean; Leary, Sue; Roi, Annett; van der Valk, Jan; Wood, Mary; Dörendahl, Antje; Köhler-Hahn, Dorothea; Box, Rainer; Spielmann, Horst

    2004-01-01

    In the member states of the EU and in the USA, scientists are obliged by animal welfare legislation not to conduct an animal experiment if another scientifically satisfactory method is reasonably and practicably available. To meet the regulatory obligation to use alternatives to animal experiments, scientists should consult literature and other relevant sources on alternatives prior to any experimental study on laboratory animals. It is the responsibility of the individual scientist to select the most appropriate database to obtain information on alternatives, which have been defined as methods that refine, reduce or replace animal experiments (the 3 Rs concept of Russell and Burch (1959)). Specialised information services provide support to scientists searching for publications on alternative methods. On occasion of a workshop in Berlin in November 2003, representatives of animal welfare information centres discussed currently available information sources on alternative methods, index terms for alternative methods, and search strategies based on index terms for alternative methods. ZEBET presented an investigation on the current status of indexing systems on alternative methods in established literature databases. The project analysed how the results of a search for publications on alternatives was influenced by the indexing procedure. The results of the study were exemplified by a typical search result. The results of the study indicated that the current indexing systems do not provide the required information, since not all of the relevant information is indexed under "alternative methods". The workshop participants developed recommendations for ad hoc working groups and research projects, e.g. development of suitable search strategies on alternative methods for scientists.

  19. Digital Library ImageRetrieval usingScale Invariant Feature and Relevance Vector Machine

    Directory of Open Access Journals (Sweden)

    Hongtao Zhang

    2014-10-01

    Full Text Available With the advance of digital library, the digital content develops with rich information connotation. Traditional information retrieval methods based on external characteristic and text description are unable to sufficientlyreveal and express the substance and semantic relation of multimedia information, and unable to fully reveal and describe the representative characteristics of information. Because of the abundant connotation of image content and the people’s abstract subjectivity in studying image content, the visual feature of the image is difficult to be described by key words. Therefore, this method not always can meet people’s needs, and the study of digital library image retrieval technique based on content is important to both academic research and application. At present, image retrieval methods are mainly based on the text and content, etc. But these existing algorithms have shortages, such as large errors and slow speeds. Motivated by the above fact, we in this paper propose a new approach based on relevance vector machine (RVM. The proposed approach first extracts the patch-level scale invariant image feature (SIFT, and then constructs the global features for images. The image feature is then delivered into RVM for retrieval. We evaluate the proposed approach on Corel dataset. The experimental result shows that the proposed method in this text has high accuracy when retrieves images.

  20. Assessment of Methods for Land Surface Temperature Retrieval from Landsat-5 TM Images Applicable to Multiscale Tree-Grass Ecosystem Modeling

    Directory of Open Access Journals (Sweden)

    Lidia Vlassova

    2014-05-01

    Full Text Available Land Surface Temperature (LST is one of the key inputs for Soil-Vegetation-Atmosphere transfer modeling in terrestrial ecosystems. In the frame of BIOSPEC (Linking spectral information at different spatial scales with biophysical parameters of Mediterranean vegetation in the context of global change and FLUXPEC (Monitoring changes in water and carbon fluxes from remote and proximal sensing in Mediterranean “dehesa” ecosystem projects LST retrieved from Landsat data is required to integrate ground-based observations of energy, water, and carbon fluxes with multi-scale remotely-sensed data and assess water and carbon balance in ecologically fragile heterogeneous ecosystem of Mediterranean wooded grassland (dehesa. Thus, three methods based on the Radiative Transfer Equation were used to extract LST from a series of 2009–2011 Landsat-5 TM images to assess the applicability for temperature input generation to a Landsat-MODIS LST integration. When compared to surface temperatures simulated using MODerate resolution atmospheric TRANsmission 5 (MODTRAN 5 with atmospheric profiles inputs (LSTref, values from Single-Channel (SC algorithm are the closest (root-mean-square deviation (RMSD = 0.50 °C; procedure based on the online Radiative Transfer Equation Atmospheric Correction Parameters Calculator (RTE-ACPC shows RMSD = 0.85 °C; Mono-Window algorithm (MW presents the highest RMSD (2.34 °C with systematical LST underestimation (bias = 1.81 °C. Differences between Landsat-retrieved LST and MODIS LST are in the range of 2 to 4 °C and can be explained mainly by differences in observation geometry, emissivity, and time mismatch between Landsat and MODIS overpasses. There is a seasonal bias in Landsat-MODIS LST differences due to greater variations in surface emissivity and thermal contrasts between landcover components.

  1. Discussion on methods and skills of legal information retrieval%论法律信息检索的方法与技巧

    Institute of Scientific and Technical Information of China (English)

    何锋

    2012-01-01

    法律信息检索是从事法学研究和其他相关法律工作的前提和基础,因此,为法律工作者提供便捷的检索渠道一直是资料管理者和文献学研究人员的重要职责,其中法律信息资源和法律信息检索方法的梳理和介绍至关重要。法律信息检索的步骤主要包括确定检索词、选取检索工具以及分析评价检索结果等几个阶段,只有熟练掌握检索的步骤和技巧,才能在浩如烟海的信息资源中查找到用户需要的法律信息。%Legal information retrieval is the premise and bases for law research and other relevant work. Therefore, it is the key accountability of database managers and philological researchers to provide convenient searching channels for law workers, among which the understanding and introductions of legal resources as well as searching methods are extremely important. Legal information retrieval has several stages including confirming index words, choosing search toois, analyzing and evaluating results. Only if indi- viduals master searching steps and skills proficiently can they find needed legal information in the substantial amount of resources.

  2. Use of In Situ Cloud Condensation Nuclei, Extinction, and Aerosol Size Distribution Measurements to Test a Method for Retrieving Cloud Condensation Nuclei Profiles From Surface Measurements

    Science.gov (United States)

    Ghan, Stephen J.; Rissman, Tracey A.; Ellman, Robert; Ferrare, Richard A.; Turner, David; Flynn, Connor; Wang, Jian; Ogren, John; Hudson, James; Jonsson, Haflidi H.; VanReken, Timothy; Flagan, Richard C.; Seinfeld, John H.

    2006-01-01

    If the aerosol composition and size distribution below cloud are uniform, the vertical profile of cloud condensation nuclei (CCN) concentration can be retrieved entirely from surface measurements of CCN concentration and particle humidification function and surface-based retrievals of relative humidity and aerosol extinction or backscatter. This provides the potential for long-term measurements of CCN concentrations near cloud base. We have used a combination of aircraft, surface in situ, and surface remote sensing measurements to test various aspects of the retrieval scheme. Our analysis leads us to the following conclusions. The retrieval works better for supersaturations of 0.1% than for 1% because CCN concentrations at 0.1% are controlled by the same particles that control extinction and backscatter. If in situ measurements of extinction are used, the retrieval explains a majority of the CCN variance at high supersaturation for at least two and perhaps five of the eight flights examined. The retrieval of the vertical profile of the humidification factor is not the major limitation of the CCN retrieval scheme. Vertical structure in the aerosol size distribution and composition is the dominant source of error in the CCN retrieval, but this vertical structure is difficult to measure from remote sensing at visible wavelengths.

  3. Two Methods for Retrieving UV Index for All Cloud Conditions from Sky Imager Products or Total SW Radiation Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Badosa, Jordi; Calbo, J.; McKenzie, R. L.; Liley, Ben; Gonzalez, J. A.; Forgan, B. W.; Long, Charles N.

    2014-07-01

    In the present study, we assess the cloud effects on UV Index (UVI) and total solar radiation (TR) as a function of cloud cover estimations and sunny conditions (from sky imaging products) as well as of solar zenith angle (SZA). These analyses are undertaken for a southern-hemisphere mid-latitude site where a 10-years dataset is available. It is confirmed that clouds reduce TR more than UV, in particular for obscured Sun conditions, low cloud fraction (< 60%) and large SZA (> 60º). Similarly, clouds enhance TR more than UV, mainly for visible Sun conditions, large cloud fraction and large SZA. Two methods to estimate UVI are developed: 1) from sky imaging cloud cover and sunny conditions, and 2) from TR measurements. Both methods may be used in practical operational applications, although Method 2 shows overall the best performance, since TR allows accounting for cloud optical properties. The mean absolute differences of Method 2 estimations with respect to measured values are 0.17 UVI units (for 1-minute data) and 0.79 Standard Erythemal Dose (SED) units (for daily integrations). Method 1 shows less accurate results but it is still suitable to estimate UVI: mean absolute differences are 0.37 UVI units and 1.6 SED.

  4. A Fast Image Retrieval Method Based on Block Color Histogram Indexing%基于分块颜色直方图索引的快速图像检索方法

    Institute of Scientific and Technical Information of China (English)

    罗桂娥; 李花; 刘献如

    2014-01-01

    The image retrieval based on content is one of the most important thing of the big data processing. In this paper, the algorithm proposed a fast image retrieval method based on block color histogram index from the human visual perception characteristics and by refering to the local image correlation. Plenty of the experimental results show that the method has a better retrieval effect, greatly shortens the retrieval time, achieves a fast retrieval.%基于内容的图像检索是大数据处理的重要内容之一,本文从人眼视觉感知特性出发,参考局部图像相关性,提出了一种基于分块颜色直方图索引的快速图像检索方法。实验结果表明,本文方法具有较好的检索效果,缩短了检索时间,实现了快速检索。

  5. Medical Image Retrieval Based on Multi-Layer Resampling Template

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-rui; YANG Yun-feng

    2014-01-01

    Medical image application in clinical diagnosis and treatment is becoming more and more widely, How to use a large number of images in the image management system and it is a very important issue how to assist doctors to analyze and diagnose. This paper studies the medical image retrieval based on multi-layer resampling template under the thought of the wavelet decomposition, the image retrieval method consists of two retrieval process which is coarse and fine retrieval. Coarse retrieval process is the medical image retrieval process based on the image contour features. Fine retrieval process is the medical image retrieval process based on multi-layer resampling template, a multi-layer sampling operator is employed to extract image resampling images each layer, then these resampling images are retrieved step by step to finish the process from coarse to fine retrieval.

  6. The Akp-Btk value method and the results for the retrieval of the parameters of the Earth's free core nutation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free Core Nutation (FCN), from the Earth's liquid core resonance of gravity tide waves on the diurnal frequency band. Since 1987, some scientists in many different countries have come to calculate the parameters of FCN by using the observational data of gravity tide waves on the diurnal frequency band. They basically followed the Stacking method, which needed five diurnal waves for the resolution. In this paper, authors introduced the Akp-Btk value method with clearly geometrical meaning as a new method, which only requires three very high signal-noise-ratio waves O1, K1 and P1 for the resolution. Authors chose the observational data of the three superconducting gravimeter stations respectively located in Cantley of Canada, Wuhan of China and Brussels of Belgium, to compute the parameters of FCN. It was the first time that the observational results of the parameters of FCN obtained from gravitational tide were in accord with the parameters of FCN gained from VLBI since 1987.

  7. Characterisation of GOME-2 formaldehyde retrieval sensitivity

    Directory of Open Access Journals (Sweden)

    W. Hewson

    2013-02-01

    Full Text Available Formaldehyde (CH2O is an important tracer of tropospheric photochemistry, whose slant column abundance can be retrieved from satellite measurements of solar backscattered UV radiation, using differential absorption retrieval techniques. In this work a spectral fitting sensitivity analysis is conducted on CH2O slant columns retrieved from the Global Ozone Monitoring Experiment 2 (GOME-2 instrument. Despite quite different spectral fitting approaches, the retrieved CH2O slant columns have geographic distributions that generally match expected CH2O sources, though the slant column magnitudes and corresponding uncertainties are particularly sensitive to the retrieval set-up. The choice of spectral fitting window, polynomial order, I0 correction, and inclusion of minor absorbers tend to result in the largest modulations of retrieved slant column magnitude and fit quality. However, application of a reference sector correction using observations over the remote Pacific Ocean is shown to largely homogenise the resulting CH2O vertical columns obtained with different retrieval settings, thereby largely reducing any systematic error sources from spectral fitting.

  8. A new method for retrieval of the extinction coefficient of water clouds by using the tail of the CALIOP signal

    Directory of Open Access Journals (Sweden)

    J. Li

    2010-11-01

    Full Text Available A method is developed based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO level 1 attenuated backscatter profile data for deriving the mean extinction coefficient of water droplets close to cloud top. The method is applicable to low level (cloud top < 2 km, opaque water clouds in which the lidar signal is completely attenuated beyond about 100 m of penetration into the cloud. The photo multiplier tubes (PMTs of 532 nm detectors (parallel and perpendicular polarizations of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP both exhibit a non-ideal recovery of the lidar signal after striking a strongly backscattering target (such as water cloud or surface. Therefore, the effects of any transient responses of CALIOP on the attenuated backscatter profile of the water cloud must first be removed in order to obtain a reliable (validated attenuated backscatter profile. Then, the slope of the exponential decay of the validated water cloud attenuated backscatter profile, and the multiple scattering factor are used for deriving the mean extinction coefficient of low-level water cloud droplets close to cloud top. This novel method was evaluated and compared with the previous method by combining the cloud effective radius (3.7 μm reported by MODIS with the lidar depolarization ratios measured by CALIPSO to estimate the mean extinction coefficient. Statistical results show that the extinction coefficients derived by the new method based on CALIOP alone agree reasonably well with those obtained in the previous study using combined CALIOP and MODIS data. Their mean absolute relative difference in extinction coefficient is about 13.4%. An important advantage of the new method is that it can be used to derive the extinction coefficient also during night time, and it is also applicable when multi-layered clouds are present. Overall, the global mean cloud water extinction coefficients during different seasons range from 26

  9. Use of the maximum entropy method to retrieve the vertical atmospheric ozone profile and predict atmospheric ozone content

    Science.gov (United States)

    Turner, B. Curtis

    1992-01-01

    A method is developed for prediction of ozone levels in planetary atmospheres. This method is formulated in terms of error covariance matrices, and is associated with both direct measurements, a priori first guess profiles, and a weighting function matrix. This is described by the following linearized equation: y = A(matrix) x X + eta, where A is the weighting matrix and eta is noise. The problems to this approach are: (1) the A matrix is near singularity; (2) the number of unknowns in the profile exceeds the number of data points, therefore, the solution may not be unique; and (3) even if a unique solution exists, eta may cause the solution to be ill conditioned.

  10. Gradient Correlation Method for the Stabilization of Inversion Results of Aerosol Microphysical Properties Retrieved from Profiles of Optical Data

    Directory of Open Access Journals (Sweden)

    Kolgotin Alexei

    2016-01-01

    Full Text Available Correlation relationships between aerosol microphysical parameters and optical data are investigated. The results show that surface-area concentrations and extinction coefficients are linearly correlated with a correlation coefficient above 0.99 for arbitrary particle size distribution. The correlation relationships that we obtained can be used as constraints in our inversion of optical lidar data. Simulation studies demonstrate a significant stabilization of aerosol microphysical data products if we apply the gradient correlation method in our traditional regularization technique.

  11. Evaluation of Information Retrieval Systems

    Directory of Open Access Journals (Sweden)

    Keneilwe Zuva

    2012-07-01

    Full Text Available One of the challenges of modern information retrieval is to adequately evaluate Information RetrievalSystem (IRS in order to estimate future performance in a specified application domain. Since there aremany algorithms in literature the decision to select one for usage depends mostly on the evaluation of thesystems’ performance in the domain. This paper presents how visual and scalar evaluation methodscomplement one another to adequately evaluate information retrieval systems. The visual evaluationmethods are capable of indicating whether one IRS performs better than another IRS fully or partially. Anoverall performance of IRS is revealed using scalar evaluation methods. The use of both types of evaluationmethods will give a clear picture of the performance of the IRSs. The Receiver Operator Characteristic(ROC curve and Precision-Recall (P-R curve were used to illustrate the visual evaluation methods. Scalarmethods notably precision, recall, Area Under Curve (AUC and F measure were used.

  12. Semantic Retrieval Optimization Method Based on Multithreaded Particle Edge Expression%多线程粒子边缘表达的语义检索优化方法

    Institute of Scientific and Technical Information of China (English)

    刘兴明

    2015-01-01

    The semantic retrieval optimization design is performed to improve the retrieval precision and recall, this paper puts forward a semantic retrieval optimization algorithm based on multithreaded particle edge expression. The semantic retrieval multithreading task scheduling platform is designed in which the semantic concept tree is set up and the search sensitivity of search engine for text feature is optimized. The multithreaded particle edge expression algorithm is designed to perform semantic feature analysis, improve multithreaded particle edge expression separation of semantics and enhances the retrieval performance. The simulation results show that this method can improve the retrieval precision and recall, shorten the retrieval time and enhance the performance.%为了提高语义检索的查准率和查全率,进行语义检索优化设计,提出一种基于多线程粒子边缘表达的语义检索优化算法,构建语义检索多线程任务调度平台,在平台中进行语义概念树构建,优化搜索引擎对文本特征的搜索敏感度,设计多线程粒子边缘表达算法进行语义特征分析,实现语义的多线程粒子边缘表达离散度增强,提高检索性能。仿真结果表明,采用该方法能提高语义检索的查全率和查准率,检索时间缩短,性能优越。

  13. The potential of distance sampling methods to estimate abundance of mountain ungulates: review of usefulness and limitations

    Directory of Open Access Journals (Sweden)

    Pérez, J. M.

    2002-12-01

    Full Text Available Accurate assessment of the populations of mountain ungulates is difficult. Topography and behaviour of animals are important factors influencing detectability, on which direct methods are based. Sympathry with other wild and domestic ungulates increases error of dung identification. Other factors, such as the size of the area to be surveyed, or unmarked populations of the target species, suggests the choice of curvilinear transects. If the basic assumptions of Distance Sampling methodology are met, then estimates of population density and accuracy can be obtained. Current technology (GPS, laser rangefinders, and G.I.S. can be used to achieve accurate measurements of distances and angles. A crucial problem is to estimate the effective area sampled around each travelling path. Therefore, researchers and managers of mountain ungulates need an adaptation of Distance Sampling methodology to account for a tridimensional scenario imposed by the slope of mountains. There is also a requirement to standardize protocols for collecting data. Alternatives for design surveys and collection data when working with populations of mountain ungulates are discussed.

    [fr]
    L'estimation précise de l'abondance des ongulés de montagne devient difficile. La détectabilité est conditionnée par la topographie et le comportement des animaux; c'est sur ce dernier cas que les méthodes directes s'appuient. La sympatrie entre les ongulés sauvages et domestiques augmente l'erreur d'identification des excréments. D'autres facteurs, comme par exemple les grandes surfaces à surveiller ou les populations non marquées des espèces-cibles, peuvent nous conduire à des comptages sur transect curvilignes ou sur des points. Si l'on tient compte des idées basiques concernant la méthodologie appelée «Échantillonage à distance», alors les estimations correspondantes de densité avec leurs mesures de précision peuvent être obtenues. La technologie à notre port

  14. Inter-comparison of four remote sensing based surface energy balance methods to retrieve surface evapotranspiration and water stress of irrigated fields in semi-arid climate

    Directory of Open Access Journals (Sweden)

    J. Chirouze

    2013-01-01

    Full Text Available Remotely sensed surface temperature can provide a good proxy for water stress level and is therefore particularly useful to estimate spatially distributed evapotranspiration. Instantaneous stress levels or instantaneous latent heat flux are deduced from the surface energy balance equation constrained by this equilibrium temperature. Pixel average surface temperature depends on two main factors: stress and vegetation fraction cover. Methods estimating stress vary according to the way they treat each factor. Two families of methods can be defined: the contextual methods, where stress levels are scaled on a given image between hot/dry and cool/wet pixels for a particular vegetation cover, and single-pixel methods which evaluate latent heat as the residual of the surface energy balance for one pixel independently from the others. Four models, two contextual (S-SEBI and a triangle method, inspired by Moran et al., 1994 and two single-pixel (TSEB, SEBS are applied at seasonal scale over a four by four km irrigated agricultural area in semi-arid northern Mexico. Their performances, both at local and spatial standpoints, are compared relatively to energy balance data acquired at seven locations within the area, as well as a more complex soil-vegetation-atmosphere transfer model forced with true irrigation and rainfall data. Stress levels are not always well retrieved by most models, but S-SEBI as well as TSEB, although slightly biased, show good performances. Drop in model performances is observed when vegetation is senescent, mostly due to a poor partitioning both between turbulent fluxes and between the soil/plant components of the latent heat flux and the available energy. As expected, contextual methods perform well when extreme hydric and vegetation conditions are encountered in the same image (therefore, esp. in spring and early summer while they tend to exaggerate the spread in water status in more homogeneous conditions (esp. in winter.

  15. Inter-comparison of four remote sensing based surface energy balance methods to retrieve surface evapotranspiration and water stress of irrigated fields in semi-arid climate

    Science.gov (United States)

    Chirouze, J.; Boulet, G.; Jarlan, L.; Fieuzal, R.; Rodriguez, J. C.; Ezzahar, J.; Er-Raki, S.; Bigeard, G.; Merlin, O.; Garatuza-Payan, J.; Watts, C.; Chehbouni, G.

    2013-01-01

    Remotely sensed surface temperature can provide a good proxy for water stress level and is therefore particularly useful to estimate spatially distributed evapotranspiration. Instantaneous stress levels or instantaneous latent heat flux are deduced from the surface energy balance equation constrained by this equilibrium temperature. Pixel average surface temperature depends on two main factors: stress and vegetation fraction cover. Methods estimating stress vary according to the way they treat each factor. Two families of methods can be defined: the contextual methods, where stress levels are scaled on a given image between hot/dry and cool/wet pixels for a particular vegetation cover, and single-pixel methods which evaluate latent heat as the residual of the surface energy balance for one pixel independently from the others. Four models, two contextual (S-SEBI and a triangle method, inspired by Moran et al., 1994) and two single-pixel (TSEB, SEBS) are applied at seasonal scale over a four by four km irrigated agricultural area in semi-arid northern Mexico. Their performances, both at local and spatial standpoints, are compared relatively to energy balance data acquired at seven locations within the area, as well as a more complex soil-vegetation-atmosphere transfer model forced with true irrigation and rainfall data. Stress levels are not always well retrieved by most models, but S-SEBI as well as TSEB, although slightly biased, show good performances. Drop in model performances is observed when vegetation is senescent, mostly due to a poor partitioning both between turbulent fluxes and between the soil/plant components of the latent heat flux and the available energy. As expected, contextual methods perform well when extreme hydric and vegetation conditions are encountered in the same image (therefore, esp. in spring and early summer) while they tend to exaggerate the spread in water status in more homogeneous conditions (esp. in winter).

  16. On Natural Language Retrieval%论自然语言检索

    Institute of Scientific and Technical Information of China (English)

    张翠玲

    2003-01-01

    With its advantages in information retrieval, such as simple in indexing and convenient in information re-trieval, natural language is now widely used in idonnafion retrieval and network retrieval. However, due to some charac-teristics of the natural language itself, its retrieval result is usually tmsafisfactory. This paper sumamrizes several main fac-tots that restrict natural language retrieval and introduces a concept space method to improve its retrieval efficiency.

  17. Comparing Methods for Land Surface Temperature Retrieval over Heterogeneous Land Cover Using Landsat-5 TM Thermal Infrared Data

    Science.gov (United States)

    Windahl, E.; de Beurs, K.

    2014-12-01

    Among other applications, remotely sensed land surface temperature (LST) has become critical for monitoring the surface urban heat island (SUHI) effect in cities across the world. While daily MODIS thermal infrared data is invaluable for examining changes in LST over time, the large 1 km spatial resolution makes studying the spatial patterns of LST in a heterogeneous urban environment difficult. The 120 m spatial resolution of Landsat 4-5 TM, as well the archive of data stretching back to 1982, make Landsat 4-5 TM sensors valuable resources for thermal data, especially in urban areas. However, the difficulty accurately correcting for atmospheric effects with only one thermal band, as well as the necessity for a priori knowledge of land surface emissivity (LSE), mean it is underutilized. Research to determine best practices for deriving LST from Landsat TM data given homogenous, usually vegetated land cover is relatively extensive; however, the accuracy of these methods given heterogeneous land cover is less well known, especially given Land Surface Emissivity (LSE) calculations that often rely heavily on NDVI. In order to determine the best methodology for measuring LST across heterogeneous land cover in the central United States, this study derives LST from Landsat 5 TM band 6 for Oklahoma City and the surrounding countryside on a fall and a spring date using three different methods: no atmospheric correction, the radiative transfer equation, and the mono-window algorithm. With all three methods, the common NDVI-based approach for estimating LSE is used; a fourth LST calculation with no atmospheric correction and an assumed emissivity of one is therefore included as contrast. Using regression analysis, these four LST measurements are compared to air temperatures recorded concurrently by approximately 40 Oklahoma Mesonet stations across the study area, and results are broken down by land cover type to explore potential biases or variations in accuracy.

  18. A Variational Method to Retrieve the Extinction Profile in Liquid Clouds Using Multiple Field-of-View Lidar

    Science.gov (United States)

    Pounder, Nicola L.; Hogan, Robin J.; Varnai, Tamas; Battaglia, Alessandro; Cahalan, Robert F.

    2011-01-01

    While liquid clouds playa very important role in the global radiation budget, it's been very difficult to remotely determine their internal cloud structure. Ordinary lidar instruments (similar to radars but using visible light pulses) receive strong signals from such clouds, but the information is limited to a thin layer near the cloud boundary. Multiple field-of-view (FOV) lidars offer some new hope as they are able to isolate photons that were scattered many times by cloud droplets and penetrated deep into a cloud before returning to the instrument. Their data contains new information on cloud structure, although the lack of fast simulation methods made it challenging to interpret the observations. This paper describes a fast new technique that can simulate multiple-FOV lidar signals and can even estimate the way the signals would change in response to changes in cloud properties-an ability that allows quick refinements in our initial guesses of cloud structure. Results for a hypothetical airborne three-FOV lidar suggest that this approach can help determine cloud structure for a deeper layer in clouds, and can reliably determine the optical thickness of even fairly thick liquid clouds. The algorithm is also applied to stratocumulus observations by the 8-FOV airborne "THOR" lidar. These tests demonstrate that the new method can determine the depth to which a lidar provides useful information on vertical cloud structure. This work opens the way to exploit data from spaceborne lidar and radar more rigorously than has been possible up to now.

  19. ARM Cloud Retrieval Ensemble Data Set (ACRED)

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, C; Xie, S; Klein, SA; McCoy, R; Comstock, JM; Delanoë, J; Deng, M; Dunn, M; Hogan, RJ; Jensen, MP; Mace, GG; McFarlane, SA; O’Connor, EJ; Protat, A; Shupe, MD; Turner, D; Wang, Z

    2011-09-12

    This document describes a new Atmospheric Radiation Measurement (ARM) data set, the ARM Cloud Retrieval Ensemble Data Set (ACRED), which is created by assembling nine existing ground-based cloud retrievals of ARM measurements from different cloud retrieval algorithms. The current version of ACRED includes an hourly average of nine ground-based retrievals with vertical resolution of 45 m for 512 layers. The techniques used for the nine cloud retrievals are briefly described in this document. This document also outlines the ACRED data availability, variables, and the nine retrieval products. Technical details about the generation of ACRED, such as the methods used for time average and vertical re-grid, are also provided.

  20. A Method of Construction for Abundant Semigroups with a CO-Adequate Transversal%具有CO-恰当断面富足半群的一种构造方法

    Institute of Scientific and Technical Information of China (English)

    李勇华; 何勇

    2008-01-01

    In this paper, we first study the structure of quasi-adequate semigroups with a cancellative monoid transversal. By using the above result, we present a method of construction for the abundant semigroups containing a CO-adequate transversal.

  1. Best, Useful and Objective Precisions for Information Retrieval of Three Search Methods in PubMed and iPubMed

    Directory of Open Access Journals (Sweden)

    Somayyeh Nadi Ravandi

    2016-10-01

    Full Text Available MEDLINE is one of the valuable sources of medical information on the Internet. Among the different open access sites of MEDLINE, PubMed is the best-known site. In 2010, iPubMed was established with an interaction-fuzzy search method for MEDLINE access. In the present work, we aimed to compare the precision of the retrieved sources (Best, Useful and Objective precision in the PubMed and iPubMed using two search methods (simple and MeSH search in PubMed and interaction-fuzzy method in iPubmed. During our semi-empirical study period, we held training workshops for 61 students of higher education to teach them Simple Search, MeSH Search, and Fuzzy-Interaction Search methods. Then, the precision of 305 searches for each method prepared by the students was calculated on the basis of Best precision, Useful precision, and Objective precision formulas. Analyses were done in SPSS version 11.5 using the Friedman and Wilcoxon Test, and three precisions obtained with the three precision formulas were studied for the three search methods. The mean precision of the interaction-fuzzy Search method was higher than that of the simple search and MeSH search for all three types of precision, i.e., Best precision, Useful precision, and Objective precision, and the Simple search method was in the next rank, and their mean precisions were significantly different (P < 0.001. The precision of the interaction-fuzzy search method in iPubmed was investigated for the first time. Also for the first time, three types of precision were evaluated in PubMed and iPubmed. The results showed that the Interaction-Fuzzy search method is more precise than using the natural language search (simple search and MeSH search, and users of this method found papers that were more related to their queries; even though search in Pubmed is useful, it is important that users apply new search methods to obtain the best results.

  2. Faster Case Retrieval Using Hash Indexing Technique

    OpenAIRE

    2011-01-01

    The main objective of case retrieval is to scan and to map the most similar old cases in case base with a new problem. Beside accurateness, the time taken to retrieve case is also important. With the increasing number of cases in case base, the retrieval task is becoming more challenging where faster retrieval time and good accuracy are the main aim. Traditionally, sequential indexing method has been applied to search for possible cases in case base. This technique worked fast when the number...

  3. A novel method to retrieve Aerosol Optical Thickness from high-resolution optical satellite images using an extended version of the Haze Optimized Transform (HOTBAR)

    Science.gov (United States)

    Wilson, Robin; Milton, Edward; Nield, Joanna

    2016-04-01

    Aerosol Optical Thickness (AOT) data has many important applications including atmospheric correction of satellite imagery and monitoring of particulate matter air pollution. Current data products are generally available at a kilometre-scale resolution, but many applications require far higher resolutions. For example, particulate matter concentrations vary on a metre-scale, and thus data products at a similar scale are required to provide accurate assessments of particle densities and allow effective monitoring of air quality and analysis of local air quality effects on health. A novel method has been developed which retrieves per-pixel AOT values from high-resolution (~30m) satellite data. This method is designed to work over a wide range of land covers - including both bright and dark surfaces - and requires only standard visible and near-infrared data, making it applicable to a range of data from sensors such as Landsat, SPOT and Sentinel-2. The method is based upon an extension of the Haze Optimized Transform (HOT). The HOT was originally designed for assessing areas of thick haze in satellite imagery by calculating a 'haziness' value for each pixel in an image as the distance from a 'Clear Line' in feature space, defined by the high correlation between visible bands. Here, we adapt the HOT method and use it to provide AOT data instead. Significant extensions include Monte Carlo estimation of the 'Clear Line', object-based correction for land cover, and estimation of AOT from the haziness values through radiative transfer modelling. This novel method will enable many new applications of AOT data that were impossible with previously available low-resolution data, and has the potential to contribute significantly to our understanding of the air quality on health, the accuracy of satellite image atmospheric correction and the role of aerosols in the climate system.

  4. Intercomparison of four remote-sensing-based energy balance methods to retrieve surface evapotranspiration and water stress of irrigated fields in semi-arid climate

    Science.gov (United States)

    Chirouze, J.; Boulet, G.; Jarlan, L.; Fieuzal, R.; Rodriguez, J. C.; Ezzahar, J.; Er-Raki, S.; Bigeard, G.; Merlin, O.; Garatuza-Payan, J.; Watts, C.; Chehbouni, G.

    2014-03-01

    Instantaneous evapotranspiration rates and surface water stress levels can be deduced from remotely sensed surface temperature data through the surface energy budget. Two families of methods can be defined: the contextual methods, where stress levels are scaled on a given image between hot/dry and cool/wet pixels for a particular vegetation cover, and single-pixel methods, which evaluate latent heat as the residual of the surface energy balance for one pixel independently from the others. Four models, two contextual (S-SEBI and a modified triangle method, named VIT) and two single-pixel (TSEB, SEBS) are applied over one growing season (December-May) for a 4 km × 4 km irrigated agricultural area in the semi-arid northern Mexico. Their performance, both at local and spatial standpoints, are compared relatively to energy balance data acquired at seven locations within the area, as well as an uncalibrated soil-vegetation-atmosphere transfer (SVAT) model forced with local in situ data including observed irrigation and rainfall amounts. Stress levels are not always well retrieved by most models, but S-SEBI as well as TSEB, although slightly biased, show good performance. The drop in model performance is observed for all models when vegetation is senescent, mostly due to a poor partitioning both between turbulent fluxes and between the soil/plant components of the latent heat flux and the available energy. As expected, contextual methods perform well when contrasted soil moisture and vegetation conditions are encountered in the same image (therefore, especially in spring and early summer) while they tend to exaggerate the spread in water status in more homogeneous conditions (especially in winter). Surface energy balance models run with available remotely sensed products prove to be nearly as accurate as the uncalibrated SVAT model forced with in situ data.

  5. 基于内容的音乐检索方法比较研究%Comparative Study of Content-based Music Retrieval Method

    Institute of Scientific and Technical Information of China (English)

    刘铬; 刘红丽

    2012-01-01

    根据基于内容的音乐检索的研究现状,分析并总结出基于内容的音乐检索的概念和原理,介绍和比较了基于内容的三种音乐检索方法,并分析了基于内容的音乐检索工具所面临的挑战,展望了该领域研究发展前景。%This paper,based on the research status of the content-based musical retrieval, analyzes and summarizes the concept and theory of the content of the content-based music retrieval, introduces and compares the four types of content-based music retrieval, and analyzes the challenges of the content-based musical retrieval and the prospects of the development of research in this field.

  6. Generating Concise Rules for Human Motion Retrieval

    Science.gov (United States)

    Mukai, Tomohiko; Wakisaka, Ken-Ichi; Kuriyama, Shigeru

    This paper proposes a method for retrieving human motion data with concise retrieval rules based on the spatio-temporal features of motion appearance. Our method first converts motion clip into a form of clausal language that represents geometrical relations between body parts and their temporal relationship. A retrieval rule is then learned from the set of manually classified examples using inductive logic programming (ILP). ILP automatically discovers the essential rule in the same clausal form with a user-defined hypothesis-testing procedure. All motions are indexed using this clausal language, and the desired clips are retrieved by subsequence matching using the rule. Such rule-based retrieval offers reasonable performance and the rule can be intuitively edited in the same language form. Consequently, our method enables efficient and flexible search from a large dataset with simple query language.

  7. Content-based retrieval of visual information

    NARCIS (Netherlands)

    Oerlemans, Adrianus Antonius Johannes

    2011-01-01

    In this dissertation, I investigate new approaches relevant to content-based image retrieval techniques. First, the MOD paradigm is proposed, a method for detecting salient points in images. These salient points are specifically designed to enhance image retrieval accuracy by maximizing distinctive

  8. Fuzzy Set Theoretical Approach to Document Retrieval.

    Science.gov (United States)

    Radecki, Tadeusz

    1979-01-01

    Presents a new method of document retrieval based on the fundamental operations of fuzzy set theory. Basic notions are introduced. Then the syntax and semantics of the proposed language for document retrieval is given, and an algorithm allocating documents to particular queries is described and its properties are discussed. (Author/CWM)

  9. Applications of Optical Technology: Information Retrieval.

    Science.gov (United States)

    O'Connor, Mary Ann

    1991-01-01

    Discusses applications of optical technology, especially CD-ROMs, to information management needs. Information retrieval problems are discussed; design questions that concern the format of the data, indexing methods, and retrieval capabilities are presented; the need for updates is considered; access requirements are discussed; and the importance…

  10. A NEW TEXTURE IMAGE RETRIEVAL WAY

    Institute of Scientific and Technical Information of China (English)

    Wang Zuyuan; Luo Lin; Zhuang Zhenquan

    2001-01-01

    This paper proposes a new texture image retrieval method for the considering of the population search and random information exchange merits of evolving programming which can be used to optimize image feature vector extraction. The experimental results show that this way can efficiently improve the retrieval accuracy and realize fasttips with the advantage of evolving programming algorithm.

  11. The Ecosystem of Information Retrieval

    Science.gov (United States)

    Rodriguez-Munoz, Jose-Vicente; Martinez-Mendez, Francisco-Javier; Pastor-Sanchez, Juan-Antonio

    2012-01-01

    Introduction: This paper presents an initial proposal for a formal framework that, by studying the metric variables involved in information retrieval, can establish the sequence of events involved and how to perform it. Method: A systematic approach from the equations of Shannon and Weaver to establish the decidability of information retrieval…

  12. An Introduction to Information Retrieval.

    Science.gov (United States)

    International Business Machines Corp., White Plains, NY. Data Processing Div.

    The ways in which digital computers can be used in information storage and retrieval are presented in the language of the nonspecialist. Indexing methods, file organization, and search strategies are discussed and a brief bibliography containing 30 IBM publications is given. The manual is intended as a first reader for those interested in the…

  13. Retrieving soil surface temperature under snowpack using special sensor microwave/imager brightness temperature in forested areas of Heilongjiang, China: an improved method

    Science.gov (United States)

    Zheng, Xingming; Li, Xiaofeng; Jiang, Tao; Ding, Yanling; Wu, Lili; Zhang, Shiyi; Zhao, Kai

    2016-04-01

    Soil surface temperature (Ts) is an important indicator of global temperature change and a key input parameter for retrieving land surface variables using remote sensing techniques. Due to the masking in the thermal infrared band and the scattering in the microwave band of snow, the temperature of soil surfaces covered by snow is difficult to infer from remote sensing data. We attempted to estimate Ts under snow cover using brightness temperature data from the special sensor microwave/imager. Ts under snow cover was underestimated due to the strong scattering effect of snow on upward soil microwave emissions at 37 GHz. The underestimated portion of Ts is related to snow properties, such as depth, grain size, and moisture. Based on the microwave emission model of layered snowpacks, the simulated results revealed a linear relationship between the underestimated Ts and the brightness temperature difference (TBD) at 19 and 37 GHz. When TBDs at 19 and 37 GHz were introduced to the Ts estimation method, accuracy improved, i.e., the root mean square error and bias of the estimated Ts decreased greatly, especially for dry snow. This improvement allows Ts estimation of snow-covered surfaces from 37 GHz microwave brightness temperature.

  14. Exploiting the power law distribution properties of satellite fire radiative power retrievals: A method to estimate fire radiative energy and biomass burned from sparse satellite observations

    Science.gov (United States)

    Kumar, S. S.; Roy, D. P.; Boschetti, L.; Kremens, R.

    2011-10-01

    Instantaneous estimates of the power released by fire (fire radiative power, FRP) are available with satellite active fire detection products. The temporal integral of FRP provides an estimate of the fire radiative energy (FRE) that is related linearly to the amount of biomass burned needed by the atmospheric emissions modeling community. The FRE, however, is sensitive to satellite temporal and spatial FRP undersampling due to infrequent satellite overpasses, cloud and smoke obscuration, and failure to detect cool and/or small fires. Satellite FRPs derived over individual burned areas and fires have been observed to exhibit power law distributions. This property is exploited to develop a new way to derive FRE, as the product of the fire duration and the expected FRP value derived from the FRP power law probability distribution function. The method is demonstrated and validated by the use of FRP data measured with a dual-band radiometer over prescribed fires in the United States and by the use of FRP data retrieved from moderate resolution imaging spectroradiometer (MODIS) active-fire detections over Brazilian deforestation and Australian savanna fires. The biomass burned derived using the conventional FRP temporal integration and power law FRE estimation methods is compared with biomass burned measurements (prescribed fires) and available fuel load information reported in the literature (Australian and Brazilian fires). The results indicate that the FRE power law derivation method may provide more reliable burned biomass estimates under sparse satellite FRP sampling conditions and correct for satellite active-fire detection omission errors if the FRP power law distribution parameters and the fire duration are known.

  15. Language-based multimedia information retrieval

    OpenAIRE

    De Jong; Gauvain, J.L.; Hiemstra, D; Netter, K.

    2000-01-01

    This paper describes various methods and approaches for language-based multimedia information retrieval, which have been developed in the projects POP-EYE and OLIVE and which will be developed further in the MUMIS project. All of these project aim at supporting automated indexing of video material by use of human language technologies. Thus, in contrast to image or sound-based retrieval methods, where both the query language and the indexing methods build on non-linguistic data, these methods...

  16. A Survey of Content-Based Video Retrieval

    Directory of Open Access Journals (Sweden)

    P. Geetha

    2008-01-01

    Full Text Available This study surveys current trends/methods in video retrieval. The major themes covered by the study include shot segmentation, key frame extraction, feature extraction, clustering, indexing and video retrieval-by similarity, probabilistic, transformational, refinement and relevance feedback. This work has done in an aim to assist the upcoming researchers in the field of video retrieval, to know about the techniques and methods available for video retrieval.

  17. Phase retrieval in protein crystallography.

    Science.gov (United States)

    Liu, Zhong Chuan; Xu, Rui; Dong, Yu Hui

    2012-03-01

    Solution of the phase problem is central to crystallographic structure determination. An oversampling method is proposed, based on the hybrid input-output algorithm (HIO) [Fienup (1982). Appl. Opt. 21, 2758-2769], to retrieve the phases of reflections in crystallography. This method can extend low-resolution structures to higher resolution for structure determination of proteins without additional sample preparation. The method requires an envelope of the protein which divides a unit cell into the density region where the proteins are located and the non-density region occupied by solvents. After a few hundred to a few thousand iterations, the correct phases and density maps are recovered. The method has been used successfully in several cases to retrieve the phases from the experimental X-ray diffraction data and the envelopes of proteins constructed from structure files downloaded from the Protein Data Bank. It is hoped that this method will greatly facilitate the ab initio structure determination of proteins.

  18. 卫星遥感地面紫外辐射的参数化方法%A Parameterization Method for Retrieving Surface UVB Radiation from Satellite

    Institute of Scientific and Technical Information of China (English)

    王普才; 吕达; 李占清

    2001-01-01

    提出了一个从卫星观测推算地面UVB辐射通量密度和红斑生物紫外辐射剂量的新的参数化方法。该方法基于一个简单的模式:大气辐射传输介质被简化成三个等效层:臭氧单独构成的吸收层,空气分子、云和气溶胶粒子组成的散射层,以及地面反射层。地面紫外辐射通量密度和生物紫外辐射剂量可以由臭氧层的等效透过率、散射层和地面的联合反射率计算。臭氧层的等效透过率可由大气臭氧总量计算。散射层和地面的联合反射率可由不存在臭氧吸收的紫外或可见光通道的反射辐射强度测量得到。该反演算法形式简单,只包含很少几个可从卫星测量获得的参数。它通过了一个可靠而相对复杂的基于DISORT的紫外辐射传输模式的检验。在广泛的计算条件下,包括晴天、云天、以及混浊大气,用这个简单算法计算的地面紫外辐射通量密度和红斑生物紫外辐射剂量与精确算法的结果相差无几。另外,还实际运用这个算法利用卫星观测资料反演地面紫外辐射通量密度,与地面实际观测资料做了比较,符合较好。%A new parameterization method for retrieving surface UVB irradiance and erythemal UVB radiative dose rate is presented. This method is based on a simple concept: the earth-atmosphere system can be equivalent to three layers: absorption layer by ozone, scattering layer containing air molecules,cloud and aerosol particles, and the surface reflecting. The surface UVB irradiance and erythemal UVB dose rate can be expressed by the effective transmission of the ozone layer and united reflectivity due to the scattering layer and the surface. The effective ozone transmission is calculated from the atmospheric total ozone amount, while the united reflctivity is determined from the satellite measured reflectivity at ozone insensitive ultraviolet or visible band. The retrieval method is simple with

  19. Reconstructed key frame and object motion based video retrieval

    Science.gov (United States)

    Hu, Shuangyan; Li, Junshan; Li, Kun; Wang, Rui; Yang, Weijun

    2007-11-01

    This paper proposes a video retrieval scheme which can retrieve desired video clips from video databases using color and object motion. The retrieval method includes two steps. In the first step, get the Intra picture frames (I-frames) set from the query MPEG video and reconstruct the key frame of the video based on the set. Then, the video retrieval equals to the retrieval of the reconstructed key frame(R-key frame) and can be easily performed according the methods of content based image retrieval. The second step, the local object motion information that is local motion vector field, is extracted from the video clips set which is the result of the first step, and the final similarity of videos is measured based on the constructed directional histogram. Experimental results show that the proposed two-step retrieval method performed excellently for video retrieval.

  20. Private information retrieval

    CERN Document Server

    Yi, Xun; Bertino, Elisa

    2013-01-01

    This book deals with Private Information Retrieval (PIR), a technique allowing a user to retrieve an element from a server in possession of a database without revealing to the server which element is retrieved. PIR has been widely applied to protect the privacy of the user in querying a service provider on the Internet. For example, by PIR, one can query a location-based service provider about the nearest car park without revealing his location to the server.The first PIR approach was introduced by Chor, Goldreich, Kushilevitz and Sudan in 1995 in a multi-server setting, where the user retriev

  1. Detection of low-abundance KRAS mutations in colorectal cancer using microfluidic capillary electrophoresis-based restriction fragment length polymorphism method with optimized assay conditions.

    Directory of Open Access Journals (Sweden)

    Huidan Zhang

    Full Text Available Constitutively active KRAS mutations have been found to be involved in various processes of cancer development, and render tumor cells resistant to EGFR-targeted therapies. Mutation detection methods with higher sensitivity will increase the possibility of choosing the correct individual therapy. Here, we established a highly sensitive and efficient microfluidic capillary electrophoresis-based restriction fragment length polymorphism (µCE-based RFLP platform for low-abundance KRAS genotyping with the combination of µCE and RFLP techniques. By using our self-built sensitive laser induced fluorescence (LIF detector and a new DNA intercalating dye YOYO-1, the separation conditions of µCE for ΦX174 HaeIII DNA marker were first optimized. Then, a Mav I digested 107-bp KRAS gene fragment was directly introduced into the microfluidic device and analyzed by µCE, in which field amplified sample stacking (FASS technique was employed to obtain the enrichment of the RFLP digestion products and extremely improved the sensitivity. The accurate analysis of KRAS statuses in HT29, LS174T, CCL187, SW480, Clone A, and CX-1 colorectal cancer (CRC cell lines by µCE-based RFLP were achieved in 5 min with picoliter-scale sample consumption, and as low as 0.01% of mutant KRAS could be identified from a large excess of wild-type genomic DNA (gDNA. In 98 paraffin-embedded CRC tissues, KRAS codon 12 mutations were discovered in 28 (28.6%, significantly higher than that obtained by direct sequencing (13, 13.3%. Clone sequencing confirmed these results and showed this system could detect at least 0.4% of the mutant KRAS in CRC tissue slides. Compared with direct sequencing, the new finding of the µCE-based RFLP platform was that KRAS mutations in codon 12 were correlated with the patient's age. In conclusion, we established a sensitive, fast, and cost-effective screening method for KRAS mutations, and successfully detected low-abundance KRAS mutations in clinical

  2. Query Specific Rank Fusion for Image Retrieval.

    Science.gov (United States)

    Zhang, Shaoting; Yang, Ming; Cour, Timothee; Yu, Kai; Metaxas, Dimitris N

    2015-04-01

    Recently two lines of image retrieval algorithms demonstrate excellent scalability: 1) local features indexed by a vocabulary tree, and 2) holistic features indexed by compact hashing codes. Although both of them are able to search visually similar images effectively, their retrieval precision may vary dramatically among queries. Therefore, combining these two types of methods is expected to further enhance the retrieval precision. However, the feature characteristics and the algorithmic procedures of these methods are dramatically different, which is very challenging for the feature-level fusion. This motivates us to investigate how to fuse the ordered retrieval sets, i.e., the ranks of images, given by multiple retrieval methods, to boost the retrieval precision without sacrificing their scalability. In this paper, we model retrieval ranks as graphs of candidate images and propose a graph-based query specific fusion approach, where multiple graphs are merged and reranked by conducting a link analysis on a fused graph. The retrieval quality of an individual method is measured on-the-fly by assessing the consistency of the top candidates' nearest neighborhoods. Hence, it is capable of adaptively integrating the strengths of the retrieval methods using local or holistic features for different query images. This proposed method does not need any supervision, has few parameters, and is easy to implement. Extensive and thorough experiments have been conducted on four public datasets, i.e., the UKbench, Corel-5K, Holidays and the large-scale San Francisco Landmarks datasets. Our proposed method has achieved very competitive performance, including state-of-the-art results on several data sets, e.g., the N-S score 3.83 for UKbench.

  3. Raccoon abundance inventory report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the results of a raccoon abundance inventory on Clarence Cannon National Wildlife Refuge in 2012. Determining raccoon abundance allows for...

  4. Land Surface Temperature Retrieval from Landsat 8 TIRS—Comparison between Radiative Transfer Equation-Based Method, Split Window Algorithm and Single Channel Method

    Directory of Open Access Journals (Sweden)

    Xiaolei Yu

    2014-10-01

    Full Text Available Accurate inversion of land surface geo/biophysical variables from remote sensing data for earth observation applications is an essential and challenging topic for the global change research. Land surface temperature (LST is one of the key parameters in the physics of earth surface processes from local to global scales. The importance of LST is being increasingly recognized and there is a strong interest in developing methodologies to measure LST from the space. Landsat 8 Thermal Infrared Sensor (TIRS is the newest thermal infrared sensor for the Landsat project, providing two adjacent thermal bands, which has a great benefit for the LST inversion. In this paper, we compared three different approaches for LST inversion from TIRS, including the radiative transfer equation-based method, the split-window algorithm and the single channel method. Four selected energy balance monitoring sites from the Surface Radiation Budget Network (SURFRAD were used for validation, combining with the MODIS 8 day emissivity product. For the investigated sites and scenes, results show that the LST inverted from the radiative transfer equation-based method using band 10 has the highest accuracy with RMSE lower than 1 K, while the SW algorithm has moderate accuracy and the SC method has the lowest accuracy.

  5. 运用Kano模型分析方法开展科技查新顾客满意度调查%Developing the Customer Satisfaction Investigation of Sci-tech Novelty Retrieval by Using the Kano Model Analysis Method

    Institute of Scientific and Technical Information of China (English)

    吕晓丽; 王晓丽; 蔚洁

    2014-01-01

    By using the kano model analysis method, this paper carries out the customer satisfaction investigation of sci-tech novelty retrieval,and determines the factors affecting the customer satisfaction, which include the connotation demands for sci-tech novelty retrieval report (report quality and novelty retrieval conclusion), denotation demands (service needs, psychological needs,and cultural needs, etc.),price demands(price and price elasticity)and 13 indicators covered by them, and based on the Kano classification,puts forward some measures for improving the quality of sci-tech novelty retrieval service.%运用Kano模型分析方法对科技查新工作进行顾客满意度调查,确定了影响科技查新顾客满意度的因素,包括查新报告的内涵需求(查新报告质量、查新结论)、外延需求(服务需求、心理需求、文化需求等)、价格需求(价位、价格弹性)及所涵盖的13个指标,并根据Kano分类提出了改进科技查新服务的措施。

  6. Arabic Studies’ Progress in Information Retrieval

    Directory of Open Access Journals (Sweden)

    Essam Hanandeh

    2016-02-01

    Full Text Available The field of information retrieval has witnessed tangible progress over the past decades in response to the expanded usage of the internet and the dire need of users to search for massive amounts of digital information. Given the steady increase of Arabic e-content, excellent information retrieval systems must be devised to suit the nature and requirements of the Arabic language. This paper sheds light on the current progress in the field of Arabic information retrieval, identifies the challenges that hinder the progress of this science, and proposes suggestions for further research. This paper uses the descriptive analytical method to examine the reality of Arabic studies in the field of information retrieval and to study the problems that are being faced in this area. Specifically, the previous literature on information retrieval is reviewed by searching the related databases and websites.

  7. Probabilistic Aspects in Spoken Document Retrieval

    Directory of Open Access Journals (Sweden)

    Macherey Wolfgang

    2003-01-01

    Full Text Available Accessing information in multimedia databases encompasses a wide range of applications in which spoken document retrieval (SDR plays an important role. In SDR, a set of automatically transcribed speech documents constitutes the files for retrieval, to which a user may address a request in natural language. This paper deals with two probabilistic aspects in SDR. The first part investigates the effect of recognition errors on retrieval performance and inquires the question of why recognition errors have only a little effect on the retrieval performance. In the second part, we present a new probabilistic approach to SDR that is based on interpolations between document representations. Experiments performed on the TREC-7 and TREC-8 SDR task show comparable or even better results for the new proposed method than other advanced heuristic and probabilistic retrieval metrics.

  8. Efficient Graffiti Image Retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chunlei; Wong, Pak C.; Ribarsky, William; Fan, Jianping

    2012-07-05

    Research of graffiti character recognition and retrieval, as a branch of traditional optical character recognition (OCR), has started to gain attention in recent years. We have investigated the special challenge of the graffiti image retrieval problem and propose a series of novel techniques to overcome the challenges. The proposed bounding box framework locates the character components in the graffiti images to construct meaningful character strings and conduct image-wise and semantic-wise retrieval on the strings rather than the entire image. Using real world data provided by the law enforcement community to the Pacific Northwest National Laboratory, we show that the proposed framework outperforms the traditional image retrieval framework with better retrieval results and improved computational efficiency.

  9. Umbilical cord Wharton's jelly repeated culture system: a new device and method for obtaining abundant mesenchymal stem cells for bone tissue engineering.

    Directory of Open Access Journals (Sweden)

    Zhengqi Chang

    Full Text Available To date, various types of cells for seeding regenerative scaffolds have been used for bone tissue engineering. Among seed cells, the mesenchymal stem cells derived from human umbilical cord Wharton's jelly (hUCMSCs represent a promising candidate and hold potential for bone tissue engineering due to the the lack of ethical controversies, accessibility, sourced by non-invasive procedures for donors, a reduced risk of contamination, osteogenic differentiation capacities, and higher immunomodulatory capacity. However, the current culture methods are somewhat complicated and inefficient and often fail to make the best use of the umbilical cord (UC tissues. Moreover, these culture processes cannot be performed on a large scale and under strict quality control. As a result, only a small quantity of cells can be harvested using the current culture methods. To solve these problems, we designed and evaluated an UC Wharton's jelly repeated culture device. Using this device, hUCMSCs were obtained from the repeated cultures and their quantities and biological characteristics were compared. We found that using our culture device, which retained all tissue blocks on the bottom of the dish, the total number of obtained cells increased 15-20 times, and the time required for the primary passage was reduced. Moreover, cells harvested from the repeated cultures exhibited no significant difference in their immunophenotype, potential for multilineage differentiation, or proliferative, osteoinductive capacities, and final osteogenesis. The application of the repeated culture frame (RCF not only made full use of the Wharton's jelly but also simplified and specified the culture process, and thus, the culture efficiency was significantly improved. In summary, abundant hUCMSCs of dependable quality can be acquired using the RCF.

  10. Retrieval of SO2 from thermal infrared satellite measurements: correction procedures for the effects of volcanic ash

    Directory of Open Access Journals (Sweden)

    A. J. Prata

    2009-02-01

    Full Text Available The simultaneous presence of SO2 and ash in a volcanic plume can lead to a significant error in the SO2 columnar abundance retrieval when multispectral Thermal InfraRed (TIR data are used. The ash particles within the plume with effective radii (from 1 to 10 μm reduce the Top Of Atmosphere (TOA radiance in the entire TIR spectral range, including the channels used for SO2 retrieval. The net effect is a significant SO2 overestimation. In this work the interference of ash is discussed and two correction procedures for satellite SO2 volcanic plume retrieval in the TIR spectral range are developed to achieve an higher computation speed and a better accuracy. The ash correction can be applied when the sensor spectral range includes the 7.3 and/or 8.7 μm SO2 absorption bands, and the split window bands centered around 11 and 12 μm required for ash retrieval. This allows the possibility of a simultaneous estimation of both volcanic SO2 and ash in the same data set. The proposed ash correction procedures have been applied to the Moderate Resolution Imaging Spectroradiometer (MODIS and the Spin Enhanced Visible and Infrared Imager (SEVIRI measurements. Data collected during the 24 November 2006 Mt. Etna eruption have been used to illustrate the technique. The SO2 and ash estimations are carried out by using a least squares fit method and the Brightness Temperature Difference (BTD procedures, respectively. The simulated TOA radiance Look-Up Table (LUT needed for the SO2 columnar abundance and the ash retrievals have been computed using the MODTRAN 4 Radiative Transfer Model. The results show the importance of the ash correction on SO2 retrieval at 8.7 μm – the SO2 columnar abundance corrected by the ash influence is less than one half of the values retrieved without the correction. The ash correction on SO2 retrieval at 7.3 μm is much less important and only significant for low SO2 columnar abundances. Results also show that the simplified and

  11. Relevance Feedback Algorithm Based on Collaborative Filtering in Image Retrieval

    Directory of Open Access Journals (Sweden)

    Yan Sun

    2010-12-01

    Full Text Available Content-based image retrieval is a very dynamic study field, and in this field, how to improve retrieval speed and retrieval accuracy is a hot issue. The retrieval performance can be improved when applying relevance feedback to image retrieval and introducing the participation of people to the retrieval process. However, as for many existing image retrieval methods, there are disadvantages of relevance feedback with information not being fully saved and used, and their accuracy and flexibility are relatively poor. Based on this, the collaborative filtering technology was combined with relevance feedback in this study, and an improved relevance feedback algorithm based on collaborative filtering was proposed. In the method, the collaborative filtering technology was used not only to predict the semantic relevance between images in database and the retrieval samples, but to analyze feedback log files in image retrieval, which can make the historical data of relevance feedback be fully used by image retrieval system, and further to improve the efficiency of feedback. The improved algorithm presented has been tested on the content-based image retrieval database, and the performance of the algorithm has been analyzed and compared with the existing algorithms. The experimental results showed that, compared with the traditional feedback algorithms, this method can obviously improve the efficiency of relevance feedback, and effectively promote the recall and precision of image retrieval.

  12. Research and Implementation of Cipher-text Data Retrieval Method Based on Cloud Storage%基于云存储的密文数据检索方法研究与实现

    Institute of Scientific and Technical Information of China (English)

    刘伯红; 王刚; 王娟娟; 史慧丽

    2014-01-01

    To solve the problem of mass data encryption retrieval in the development of cloud storage service ,a new cipher-text data retrieval method is proposed .In this method ,a new retrieval method is designed which use inverted index as the index structure .Firstly ,user inputs the query words and matches on the cipher-text index precisely and transfer the word into other forms and correct the wrong word to query again .And then repeat the above steps under the circumstance if the returned result is lower than the pre-set threshold .This cipher-text data retrieval method improves the privacy of stored data to make users obtain the results what they expect .Finally ,experimental results show that the scheme is effective .%为解决云存储服务海量加密数据检索问题,提出一个新的云存储密文数据检索方法,新方法采用倒排索引结构,首先用户输入检索词,在密文索引中匹配,然后将词转化成其他形式和纠正错误的词之后进行再次查询,在返回结果低于先前设定的临界值的情况下继续执行以上步骤。这种基于云存储的密文数据检索方法提高了存储数据的隐私性,能够使用户得到他们所期望的结果,实验结果证明新的检索方法是有效的。

  13. 信息检索课程教学改革研究--主题案例法的设计与实施%Research on Information Retrieval Course Reform:Design and Implementation of the Theme Case Teaching Method

    Institute of Scientific and Technical Information of China (English)

    黄悦深

    2016-01-01

    论文针对信息检索教学中存在的问题,以及已有的案例教学法的局限,提出了主题案例法的设计思路。该方法以主题案例作为串联课程体系的主线,能更有效地引导学生建立完整的信息检索思维,有助于实现从信息检索技能传授转向信息检索思维培育的课程改革。它按照主题案例法的设计思路构建了主题案例库,并深入探讨了主题案例库的主题结构、案例设计、内容扩展、组织形式4个关键环节的实施过程。%Aiming at the problems of the information retrieval course and the limitation of the existing case teaching method, this paper proposes the design of the theme case teaching method. This method takes the theme case as the main line to connect curriculum system, so as to guide students to establish a complete information retrieval thinking more effectively, and helps to realize the reform of the course from the teaching of information retrieval skills to the information retrieval thinking. In accordance with the theme case teaching method, it constructs the theme case library, and discusses 4 key factors including the structure, case design, content expansion, and the display of the theme case library.

  14. Retrieval options study

    Energy Technology Data Exchange (ETDEWEB)

    1980-03-01

    This Retrieval Options Study is part of the systems analysis activities of the Office of Nuclear Waste Isolation to develop the scientific and technological bases for radioactive waste repositories in various geologic media. The study considers two waste forms, high level waste and spent fuel, and defines various classes of waste retrieval and recovery. A methodology and data base are developed which allow the relative evaluation of retrieval and recovery costs and the following technical criteria: safety; technical feasibility; ease of retrieval; probable intact retrieval time; safeguards; monitoring; criticality; and licensability. A total of 505 repository options are defined and the cost and technical criteria evaluated utilizing a combination of facts and engineering judgments. The repositories evaluated are selected combinations of the following parameters: Geologic Media (salt, granite, basalt, shale); Retrieval Time after Emplacement (5 and 25 years); Emplacement Design (nominal hole, large hole, carbon steel canister, corrosion resistant canister, backfill in hole, nominal sleeves, thick wall sleeves); Emplacement Configuration (single vertical, multiple vertical, single horizontal, multiple horizontal, vaults; Thermal Considerations; (normal design, reduced density, once-through ventilation, recirculated ventilation); Room Backfill; (none, run-of-mine, early, 5 year delay, 25 year delay, decommissioned); and Rate of Retrieval; (same as emplacement, variably slower depending on repository/canister condition).

  15. TOFIR: A Tool of Facilitating Information Retrieval - Introduce a Visual Retrieval Model.

    Science.gov (United States)

    Zhang, Jin

    2001-01-01

    Introduces a new method for the visualization of information retrieval called TOFIR (Tool of Facilitating Information Retrieval). Discusses the use of angle attributes of a document to construct the angle-based visual space; two-dimensional and three-dimensional visual tools; ambiguity; and future research directions. (Author/LRW)

  16. Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs I: Characterizing Benchmarks, Gl570D and HD3651B

    CERN Document Server

    Line, Michael R; Burningham, Ben; Fortney, Jonathan; Marley, Mark

    2015-01-01

    Interpreting the spectra of brown dwarfs is key to determining the fundamental physical and chemical processes occurring in their atmospheres. Powerful Bayesian atmospheric retrieval tools have recently been applied to both exoplanet and brown dwarf spectra to tease out the thermal structures and molecular abundances to understand those processes. In this manuscript we develop a significantly upgraded retrieval method and apply it to the SpeX spectral library data of two benchmark late T-dwarfs, Gl570D and HD3651B, to establish the validity of our upgraded forward model parameterization and Bayesian estimator. Our retrieved metallicities, gravities, and effective temperature are consistent with the metallicity and presumed ages of the systems. We add the carbon-to-oxygen ratio as a new dimension to benchmark systems and find good agreement between carbon-to-oxygens ratio derived in the brown dwarfs and the host stars. Furthermore, we have for the first time unambiguously determined the presence of ammonia in ...

  17. Atmospheric Retrieval for Direct Imaging Spectroscopy of Gas Giants In Reflected Light II: Orbital Phase and Planetary Radius

    CERN Document Server

    Nayak, Michael; Marley, Mark; Fortney, Jonathan; Robinson, Tyler; Lewis, Nikole

    2016-01-01

    Future space-based telescopes, such as the Wide-Field Infrared Survey Telescope (WFIRST), will observe the reflected-light spectra of directly imaged extrasolar planets. Interpretation of such data presents a number of novel challenges, including accounting for unknown planet radius and uncertain stellar illumination phase angle. Here we report on our continued development of Markov Chain Monte Carlo retrieval methods for addressing these issues in the interpretation of such data. Specifically we explore how the unknown planet radius and potentially poorly known observer-planet-star phase angle impacts retrievals of parameters of interest such as atmospheric methane abundance, cloud properties and surface gravity. As expected, the uncertainty in retrieved values is a strong function of signal-to-noise ratio (SNR) of the observed spectra, particularly for low metallicity atmospheres, which lack deep absorption signatures. Meaningful results may only be possible above certain SNR thresholds; for cases across a ...

  18. Path indexing for term retrieval

    OpenAIRE

    1992-01-01

    Different methods for term retrieval in deduction systems have been introduced in literature. This report eviews the three indexing techniques discrimination indexing, path indexing, and abstraction tree indexing. A formal approach to path indexing is presented and algorithms as well as data structures of an existing implementation are discussed. Eventually, experiments will show that our implementation outperforms the implementation of path indexing in the OTTER theorem prover.

  19. Precision Chemical Abundance Measurements

    DEFF Research Database (Denmark)

    Yong, David; Grundahl, Frank; Meléndez, Jorge;

    2012-01-01

    This talk covers preliminary work in which we apply a strictly differential line-by-line chemical abundance analysis to high quality UVES spectra of the globular cluster NGC 6752. We achieve extremely high precision in the measurement of relative abundance ratios. Our results indicate that the ob......This talk covers preliminary work in which we apply a strictly differential line-by-line chemical abundance analysis to high quality UVES spectra of the globular cluster NGC 6752. We achieve extremely high precision in the measurement of relative abundance ratios. Our results indicate...... that the observed abundance dispersion exceeds the measurement uncertainties and that many pairs of elements show significant correlations when plotting [X1/H] vs. [X2/H]. Our tentative conclusions are that either NGC 6752 is not chemically homogeneous at the ~=0.03 dex level or the abundance variations...

  20. Exploiting salient semantic analysis for information retrieval

    Science.gov (United States)

    Luo, Jing; Meng, Bo; Quan, Changqin; Tu, Xinhui

    2016-11-01

    Recently, many Wikipedia-based methods have been proposed to improve the performance of different natural language processing (NLP) tasks, such as semantic relatedness computation, text classification and information retrieval. Among these methods, salient semantic analysis (SSA) has been proven to be an effective way to generate conceptual representation for words or documents. However, its feasibility and effectiveness in information retrieval is mostly unknown. In this paper, we study how to efficiently use SSA to improve the information retrieval performance, and propose a SSA-based retrieval method under the language model framework. First, SSA model is adopted to build conceptual representations for documents and queries. Then, these conceptual representations and the bag-of-words (BOW) representations can be used in combination to estimate the language models of queries and documents. The proposed method is evaluated on several standard text retrieval conference (TREC) collections. Experiment results on standard TREC collections show the proposed models consistently outperform the existing Wikipedia-based retrieval methods.

  1. Content Based Image Retrieval through Clustering

    Directory of Open Access Journals (Sweden)

    Sandhya

    2012-06-01

    Full Text Available Content-based image retrieval (CBIR is a technique usedfor extracting similar images from an image database.CBIR system is required to access images effectively andefficiently using information contained in image databases.Here, K-Means is to be used for Image retrieval. The Kmeansmethod can be applied only in those cases when themean of a cluster is defined. The K-means method is notsuitable for discovering clusters with non-convex shapes orclusters of very different size. In this paper, CBIR,clustering and K-Means are defined. With the help of these,the data consisting images can be grouped and retrieved.

  2. Harmonic Retrieval in Colored ARMA Noise

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We propose a new approach to harmonic retrieval in colored ARMA noise. A suitable filter is first used to remove all the sharp power spectrum peaks of the noisy observed process, then some kinds of cross correlation is employed to identify the noise characteristics. After filtering the noisy observed process with the identified noise characteristics again, SVD-TLS method can be applied to retrieve the harmonics. The proposed approach can be used to retrieve real-valued harmonic signals in colored ARMA noise with no restrictions on the phase coupling of harmonics and the distribution of the noise. Simulation examples show its effectiveness.

  3. Information retrieval system

    Science.gov (United States)

    Berg, R. F.; Holcomb, J. E.; Kelroy, E. A.; Levine, D. A.; Mee, C., III

    1970-01-01

    Generalized information storage and retrieval system capable of generating and maintaining a file, gathering statistics, sorting output, and generating final reports for output is reviewed. File generation and file maintenance programs written for the system are general purpose routines.

  4. RETRIEVAL EQUIPMENT DESCRIPTIONS

    Energy Technology Data Exchange (ETDEWEB)

    J. Steinhoff

    1997-08-25

    The objective and the scope of this document are to list and briefly describe the major mobile equipment necessary for waste package (WP) retrieval from the proposed subsurface nuclear waste repository at Yucca Mountain. Primary performance characteristics and some specialized design features of the equipment are explained and summarized in the individual subsections of this document. There are no quality assurance requirements or QA controls in this document. Retrieval under normal conditions is accomplished with the same fleet of equipment as is used for emplacement. Descriptions of equipment used for retrieval under normal conditions is found in Emplacement Equipment Descriptions, DI: BCAF00000-01717-5705-00002 (a document in progress). Equipment used for retrieval under abnormal conditions is addressed in this document and consists of the following: (1) Inclined Plane Hauler; (2) Bottom Lift Transporter; (3) Load Haul Dump (LHD) Loader; (4) Heavy Duty Forklift for Emplacement Drifts; (5) Covered Shuttle Car; (6) Multipurpose Vehicle; and (7) Scaler.

  5. Foreign Body Retrieval

    Medline Plus

    Full Text Available ... of page What are some common uses of the procedure? Foreign body retrieval is used to remove ... the foreign body. top of page What does the equipment look like? A variety of x-ray ...

  6. Content Based Video Retrieval

    Directory of Open Access Journals (Sweden)

    B. V. Patel

    2012-10-01

    Full Text Available Content based video retrieval is an approach for facilitating the searching and browsing of large image collections over World Wide Web. In this approach, video analysis is conducted on low level visual properties extracted from video frame. We believed that in order to create an effective video retrieval system, visual perception must be taken into account. We conjectured that a technique which employs multiple features for indexing and retrieval would be more effective in the discrimination and search tasks of videos. In order to validate this claim, content based indexing and retrieval systems were implemented using color histogram, various texture features and other approaches. Videos were stored in Oracle 9i Database and a user study measured correctness of response.

  7. A mixed methods approach to exploring the relationship between Norway rat (Rattus norvegicus) abundance and features of the urban environment in an inner-city neighborhood of Vancouver, Canada.

    Science.gov (United States)

    Himsworth, Chelsea G; Parsons, Kirbee L; Feng, Alice Y T; Kerr, Thomas; Jardine, Claire M; Patrick, David M

    2014-01-01

    Urban rats (Rattus spp.) are among the most ubiquitous pest species in the world. Previous research has shown that rat abundance is largely determined by features of the environment; however, the specific urban environmental factors that influence rat population density within cities have yet to be clearly identified. Additionally, there are no well described tools or methodologies for conducting an in-depth evaluation of the relationship between urban rat abundance and the environment. In this study, we developed a systematic environmental observation tool using methods borrowed from the field of systematic social observation. This tool, which employed a combination of quantitative and qualitative methodologies, was then used to identify environmental factors associated with the relative abundance of Norway rats (Rattus norvegicus) in an inner-city neighborhood of Vancouver, Canada. Using a multivariate zero-inflated negative binomial model, we found that a variety of factors, including specific land use, building condition, and amount of refuse, were related to rat presence and abundance. Qualitative data largely supported and further clarified observed statistical relationships, but also identified conflicting and unique situations not easily captured through quantitative methods. Overall, the tool helped us to better understand the relationship between features of the urban environment and relative rat abundance within our study area and may useful for studying environmental determinants of zoonotic disease prevalence/distribution among urban rat populations in the future.

  8. 体育科研文献资料检索及网络信息资源搜索方法研究%Sports Scholarly Research Literature Retrieval of Information and Search Methods Online Sports Information Resources

    Institute of Scientific and Technical Information of China (English)

    徐刚; 徐静

    2015-01-01

    This paper introduces the basic principles and methods of retrieving information sports literature. It based on the traditional library search tools and retrieval methods, and concepts and knowledge of internet-related retrieval sports literature information resources, and using of internet search engines important tool to help readers improving their application abilities of searching information by used paper document and internet, and help for increasing recall ratio and precision ration of literature data.%介绍体育文献信息的检索基本原理与方法,基于传统的图书馆的检索工具和检索方法,互联网上体育文献信息资源的检索有关概念与知识,以及Internet重要的中文搜索引擎工具的利用,提高读者在利用纸质文献资料和因特网上实际利用搜索引擎的能力,提高文献信息资料的查全率和查准率。

  9. Evaluating personal information retrieval

    OpenAIRE

    Kelly, Liadh; Bunbury, Paul; Jones, Gareth J.F.

    2012-01-01

    Evaluation of personal search over an individual’s personal information space on the desktop or elsewhere is problematic for reasons relating both to the personal and private nature of the data and the associated personal information needs of collection owners. Indeed challenges associated with evaluation in this space are recognised as one of the key factors hindering the development of research in personal information retrieval. We present the “personal information retrieval evaluatio...

  10. Quantitative evaluation of a single-distance phase-retrieval method applied on in-line phase-contrast images of a mouse lung

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Sara, E-mail: sara.mohammadi@elettra.trieste.it [The Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Synchrotron Light Source ‘Elettra’ Trieste, Strada Statale 14, km 163.5 in AREA Science Park, Basovizza 34149 (Italy); Larsson, Emanuel [Synchrotron Light Source ‘Elettra’ Trieste, Strada Statale 14, km 163.5 in AREA Science Park, Basovizza 34149 (Italy); Linköping University, SE-581 83 (Sweden); University of Trieste, Trieste (Italy); Alves, Frauke [University Hospital Goettingen, Robert Koch Strasse 40, Goettingen, Lower Saxony 37075 (Germany); Dal Monego, Simeone [Cluster in Biomedicine s.c.r.l., AREA Science Park, Strada Statale 14, km 163.5, Basovizza, 34149 Trieste (Italy); Biffi, Stefania; Garrovo, Chiara [IRCCS Burlo Garofolo, via dell’Istria 65/1, 34137 Trieste (Italy); Lorenzon, Andrea [Cluster in Biomedicine s.c.r.l., AREA Science Park, Strada Statale 14, km 163.5, Basovizza, 34149 Trieste (Italy); Tromba, Giuliana [Synchrotron Light Source ‘Elettra’ Trieste, Strada Statale 14, km 163.5 in AREA Science Park, Basovizza 34149 (Italy); Dullin, Christian, E-mail: sara.mohammadi@elettra.trieste.it [University Hospital Goettingen, Robert Koch Strasse 40, Goettingen, Lower Saxony 37075 (Germany)

    2014-05-16

    Quantitative analysis concerning the application of a single-distance phase-retrieval algorithm on in-line phase-contrast images of a mouse lung at different sample-to-detector distances is presented. Propagation-based X-ray phase-contrast computed tomography (PBI) has already proven its potential in a great variety of soft-tissue-related applications including lung imaging. However, the strong edge enhancement, caused by the phase effects, often hampers image segmentation and therefore the quantitative analysis of data sets. Here, the benefits of applying single-distance phase retrieval prior to the three-dimensional reconstruction (PhR) are discussed and quantified compared with three-dimensional reconstructions of conventional PBI data sets in terms of contrast-to-noise ratio (CNR) and preservation of image features. The PhR data sets show more than a tenfold higher CNR and only minor blurring of the edges when compared with PBI in a predominately absorption-based set-up. Accordingly, phase retrieval increases the sensitivity and provides more functionality in computed tomography imaging.

  11. Determining the absolute abundance of dinoflagellate cysts in recent marine sediments: The Lycopodium marker-grain method put to the test

    DEFF Research Database (Denmark)

    Mertens, K; Verhoeven; Verleye

    2009-01-01

    Absolute abundances (concentrations) of dinoflagellate cysts are often determined through the addition of Lycopodium clavatum marker-grains as a spike to a sample before palynological processing. An inter-laboratory calibration exercise was set up in order to test the comparability of results obt...

  12. Concept Framework for Audio Information Retrieval: ARF

    Institute of Scientific and Technical Information of China (English)

    LI GuoHui(李国辉); WU DeFeng(武德峰); ZHANG Jun(张军)

    2003-01-01

    The majority of researches on content-based retrieval focused on visual media.However audio is also an important medium and information carrier from the viewpoint of humanauditory perception, so it is needed to retrieve for audio collection. Audio is handled by conven-tional methods as an opaque stream medium, which is not suitable for information retrieval byits content. In fact, audio carries rich aural information with the form of speech, musical, andsound effects, so it could be retrieved based on its aural content, such as acoustic features, musicalmelodies and associated semantics. In this paper, a concept framework (ARF) for content-basedaudio retrieval is proposed from systematic perspectives, which describes audio content model,audio retrieval architecture and audio query schemes. Audio contents are represented by a hier-archical model and a set of formal descriptions from physical to acoustic to semantic level, whichdepict acoustic features, logical structure and semantics of audio and audio objects. The archi-tecture consisting of audio meta-database, populating and accessing modules presents a systemstructure view of audio information retrieval. The query schemes give generalized approaches andmodes concerning how users deliver audio information needs to audio collections. Finally, an audioretrieval example implemented is used to explain and specify the application of the components in the proposed ARF.

  13. An improved glyoxal retrieval from OMI measurements

    OpenAIRE

    Alvarado, L. M. A.; Richter, A; M. Vrekoussis; Wittrock, F; Hilboll, A.; S. F. Schreier; Burrows, J.P.

    2014-01-01

    Satellite observations from the SCIAMACHY, GOME-2, and OMI spectrometers have been used to retrieve atmospheric columns of glyoxal (CHOCHO) with the DOAS method. High CHOCHO levels are found over regions with large biogenic and pyrogenic emissions, and hot-spots have been identified over areas of anthropogenic activities. This study focuses on the development of an improved retrieval for CHOCHO from measurements by the OMI instrument. From sensitivi...

  14. Retrieval of SO2 from thermal infrared satellite measurements: correction procedures for the effects of volcanic ash

    Directory of Open Access Journals (Sweden)

    S. Corradini

    2009-05-01

    Full Text Available The simultaneous presence of SO2 and ash in a volcanic plume can lead to a significant error in the SO2 column abundance retrieval when multispectral Thermal InfraRed (TIR data are used. The ash particles within the plume with effective radii from 1 to 10 μm reduce the Top Of Atmosphere (TOA radiance in the entire TIR spectral range, including the channels used for SO2 retrieval. The net effect is a significant SO2 overestimation. In this work the interference of ash is discussed and two correction procedures for satellite SO2 volcanic plume retrieval in the TIR spectral range are developed to achieve an higher computational speed and a better accuracy. The ash correction can be applied when the sensor spectral range includes the 7.3 and/or 8.7 μm SO2 absorption bands, and the split window bands centered around 11 and 12 μm required for ash retrieval. This allows the possibility of simultaneous estimation of both volcanic SO2 and ash in the same data set. The proposed ash correction procedures have been applied to the Moderate Resolution Imaging Spectroradiometer (MODIS and the Spin Enhanced Visible and Infrared Imager (SEVIRI measurements. Data collected during the 24 November 2006 Mt. Etna eruption have been used to illustrate the technique. The SO2 and ash estimation is carried out by using a best weighted least squares fit method and the Brightness Temperature Difference (BTD procedures, respectively. The simulated TOA radiance Look-Up Table (LUT needed for the SO2 column abundance and the ash retrievals have been computed using the MODTRAN 4 Radiative Transfer Model. The results show the importance of the ash correction on SO2 retrievals at 8.7 μm, where the corrected SO2 column abundance values are less than 50% of the uncorrected values. The ash correction on SO2 retrieval at 7.3 μm is much less important and only significant for low SO2 column abundances. Results also show that the simplified and faster correction procedure

  15. Phase retrieval from single biomolecule diffraction pattern.

    Science.gov (United States)

    Ikeda, Shiro; Kono, Hidetoshi

    2012-02-13

    In this paper, we propose the SPR (sparse phase retrieval) method, which is a new phase retrieval method for coherent x-ray diffraction imaging (CXDI). Conventional phase retrieval methods effectively solve the problem for high signal-to-noise ratio measurements, but would not be sufficient for single biomolecular imaging which is expected to be realized with femto-second x-ray free electron laser pulses. The SPR method is based on the Bayesian statistics. It does not need to set the object boundary constraint that is required by the commonly used hybrid input-output (HIO) method, instead a prior distribution is defined with an exponential distribution and used for the estimation. Simulation results demonstrate that the proposed method reconstructs the electron density under a noisy condition even some central pixels are masked.

  16. 基于语义矩阵反馈的多特征融合三维模型检索方法%3D model retrieval method with multi-feature fusion based on semantic matrix feedback

    Institute of Scientific and Technical Information of China (English)

    胡敏; 罗珣; 马韵洁

    2012-01-01

    为解决相关反馈三维模型检索方法存在用户不能确定模型是否相似的问题,提出了一种基于语义矩阵反馈的多特征融合三维模型检索方法.首先,采用形状分布和球面调和两种特征提取算法进行多特征提取.然后,对每种特征进行检索计算,将得到的相似度进行基于语义的反馈,根据反馈结果对不同特征分配不同的权值.最后,对迭代反馈结果的权求和得到检索模型的相似度.实验结果表明,本方法的检索结果比用单一的特征提取方法得到的结果准确.%When the relevance feedback method is used to retrieve the 3D model, it has the problem that the user unclear whether the models are similar or not similar. In order to solve this problem, an integrated method of 3D model retrieval is proposed which based on the combination of semantic matrix feedback and feature. Firstly, 3D model features are extracted by using shape distributions and spherical harmonics methods. Then these features similarity of the 3D mod-els are involved to calculate the assessment weights. These assessment weights are combined with semantic matrix feed-back in the 3D model retrieval. Finally, the similarity of the 3D models is calculated based on the iterative feedback result. The experiment results show that this method is more accurate than the single feature extraction method.

  17. Die Ellbogengelenksdysplasie beim Golden Retriever

    OpenAIRE

    Gronau, Franziska

    2010-01-01

    Growth and developmental disorders of the elbow joint are frequent causes of lameness of the thoracic limb of the dog. Golden Retriever is one of the mainly affected breeds. Two different computer-aided methods of measurement will be compared in this study. The aim is to find out whether one of these measurement methods is more suitable to distinguish affected from unaffected joints and to recognize a possible predisposition for elbow dysplasia (ED). X-Rays of the elbow joints in the medio-la...

  18. OPTIMIZED IMAGE RETRIEVAL SYSTEM USING MULTIPLE THREADS

    Directory of Open Access Journals (Sweden)

    S.P. Jeyapriyamvadha

    2012-05-01

    Full Text Available Content-Based Image Retrieval is a technique used to retrieve similar images where the most challenging aspect is to bridge the gap between low level feature layout and high level semantic concepts. Efficient and effective retrieval techniques of images are desired to work out a certain image on the condition that the result would be more suitable than the input image. A novel method is proposed, which links various images as threads; where the texture features and shape features of the images are extracted and stored. The minimum distance between the query image and the thread provides the output. These threads are based upon the query result. The resultant retrieval system is found to be beneficial and interactive.

  19. DISR: Dental Image Segmentation and Retrieval.

    Science.gov (United States)

    Pilevar, Abdol Hamid

    2012-01-01

    In this paper, we propose novel algorithms for retrieving dental images from databases by their contents. Based on special information of dental images, for better content-based dental image retrieval and representation, the image attributes are used. We propose Dental Image Segmentation and Retrieval (DISR), a content-based image retrieval method that is robust to translation and scaling of the objects in the images. A novel model is used to calculate the features of the image. We implemented the dentition plaster casts and proposed a special technique for segmenting teeth in our dental study models. For testing the efficiency of the presented algorithm, a software system is developed and 60 dental study models are used. The models are covering different kinds of malocclusions. Our experiments show that 95% of the extracted results are accurate and the presented algorithm is efficient.

  20. Memory Retrieval in Mice and Men.

    Science.gov (United States)

    Ben-Yakov, Aya; Dudai, Yadin; Mayford, Mark R

    2015-10-05

    Retrieval, the use of learned information, was until recently mostly terra incognita in the neurobiology of memory, owing to shortage of research methods with the spatiotemporal resolution required to identify and dissect fast reactivation or reconstruction of complex memories in the mammalian brain. The development of novel paradigms, model systems, and new tools in molecular genetics, electrophysiology, optogenetics, in situ microscopy, and functional imaging, have contributed markedly in recent years to our ability to investigate brain mechanisms of retrieval. We review selected developments in the study of explicit retrieval in the rodent and human brain. The picture that emerges is that retrieval involves coordinated fast interplay of sparse and distributed corticohippocampal and neocortical networks that may permit permutational binding of representational elements to yield specific representations. These representations are driven largely by the activity patterns shaped during encoding, but are malleable, subject to the influence of time and interaction of the existing memory with novel information.

  1. Quantum Enhanced Phase Retrieval

    CERN Document Server

    Liberman, Liat; Poem, Eilon; Silberberg, Yaron

    2015-01-01

    The retrieval of phases from intensity measurements is a key process in many fields in science, from optical microscopy to x-ray crystallography. Here we study phase retrieval of a one-dimensional multi-phase object that is illuminated by quantum states of light. We generalize the iterative Gerchberg-Saxton algorithm to photon correlation measurements on the output plane, rather than the standard intensity measurements. We report a numerical comparison of classical and quantum phase retrieval of a small one-dimensional object of discrete phases from its far-field diffraction. While the classical algorithm was ambiguous and often converged to wrong solutions, quantum light produced a unique reconstruction with smaller errors and faster convergence. We attribute these improvements to a larger Hilbert space that constrains the algorithm.

  2. Interactive Information Retrieval

    DEFF Research Database (Denmark)

    Borlund, Pia

    2013-01-01

    The paper introduces the research area of interactive information retrieval (IIR) from a historical point of view. Further, the focus here is on evaluation, because much research in IR deals with IR evaluation methodology due to the core research interest in IR performance, system interaction...... and satisfaction with retrieved information. In order to position IIR evaluation, the Cranfield model and the series of tests that led to the Cranfield model are outlined. Three iconic user-oriented studies and projects that all have contributed to how IIR is perceived and understood today are presented......: The MEDLARS test, the Book House fiction retrieval system, and the OKAPI project. On this basis the call for alternative IIR evaluation approaches motivated by the three revolutions (the cognitive, the relevance, and the interactive revolutions) put forward by Robertson & Hancock-Beaulieu (1992) is presented...

  3. An Abstraction-Based Data Model for Information Retrieval

    Science.gov (United States)

    McAllister, Richard A.; Angryk, Rafal A.

    Language ontologies provide an avenue for automated lexical analysis that may be used to supplement existing information retrieval methods. This paper presents a method of information retrieval that takes advantage of WordNet, a lexical database, to generate paths of abstraction, and uses them as the basis for an inverted index structure to be used in the retrieval of documents from an indexed corpus. We present this method as a entree to a line of research on using ontologies to perform word-sense disambiguation and improve the precision of existing information retrieval techniques.

  4. New methods for the retrieval of chlorophyll red fluorescence from hyperspectral satellite instruments: simulations and application to GOME-2 and SCIAMACHY

    Science.gov (United States)

    Joiner, Joanna; Yoshida, Yasuko; Guanter, Luis; Middleton, Elizabeth M.

    2016-08-01

    Global satellite measurements of solar-induced fluorescence (SIF) from chlorophyll over land and ocean have proven useful for a number of different applications related to physiology, phenology, and productivity of plants and phytoplankton. Terrestrial chlorophyll fluorescence is emitted throughout the red and far-red spectrum, producing two broad peaks near 683 and 736 nm. From ocean surfaces, phytoplankton fluorescence emissions are entirely from the red region (683 nm peak). Studies using satellite-derived SIF over land have focused almost exclusively on measurements in the far red (wavelengths > 712 nm), since those are the most easily obtained with existing instrumentation. Here, we examine new ways to use existing hyperspectral satellite data sets to retrieve red SIF (wavelengths unique opportunity to compare red and far-red terrestrial SIF at regional spatial scales. Terrestrial SIF has been estimated with ground-, aircraft-, or satellite-based instruments by measuring the filling-in of atmospheric and/or solar absorption spectral features by SIF. Our approach makes use of the oxygen (O2) γ band that is not affected by SIF. The SIF-free O2 γ band helps to estimate absorption within the spectrally variable O2 B band, which is filled in by red SIF. SIF also fills in the spectrally stable solar Fraunhofer lines (SFLs) at wavelengths both inside and just outside the O2 B band, which further helps to estimate red SIF emission. Our approach is then an extension of previous approaches applied to satellite data that utilized only the filling-in of SFLs by red SIF. We conducted retrievals of red SIF using an extensive database of simulated radiances covering a wide range of conditions. Our new algorithm produces good agreement between the simulated truth and retrievals and shows the potential of the O2 bands for noise reduction in red SIF retrievals as compared with approaches that rely solely on SFL filling. Biases seen with existing satellite data, most likely

  5. UNIFORM ATMOSPHERIC RETRIEVAL ANALYSIS OF ULTRACOOL DWARFS. I. CHARACTERIZING BENCHMARKS, Gl 570D AND HD 3651B

    Energy Technology Data Exchange (ETDEWEB)

    Line, Michael R.; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Teske, Johanna [Carnegie DTM, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States); Burningham, Ben; Marley, Mark S., E-mail: mrline@ucsc.edu [NASA Ames Research Center, Mail Stop 245-3, Moffett Field, CA 94035 (United States)

    2015-07-10

    Interpreting the spectra of brown dwarfs is key to determining the fundamental physical and chemical processes occurring in their atmospheres. Powerful Bayesian atmospheric retrieval tools have recently been applied to both exoplanet and brown dwarf spectra to tease out the thermal structures and molecular abundances to understand those processes. In this manuscript we develop a significantly upgraded retrieval method and apply it to the SpeX spectral library data of two benchmark late T dwarfs, Gl 570D and HD 3651B, to establish the validity of our upgraded forward model parameterization and Bayesian estimator. Our retrieved metallicities, gravities, and effective temperatures are consistent with the metallicity and presumed ages of the systems. We add the carbon-to-oxygen ratio as a new dimension to benchmark systems and find good agreement between carbon-to-oxygen ratios derived in the brown dwarfs and the host stars. Furthermore, we have for the first time unambiguously determined the presence of ammonia in the low-resolution spectra of these two late T dwarfs. We also show that the retrieved results are not significantly impacted by the possible presence of clouds, though some quantities are significantly impacted by uncertainties in photometry. This investigation represents a watershed study in establishing the utility of atmospheric retrieval approaches on brown dwarf spectra.

  6. Information Retrieval Evaluation

    CERN Document Server

    Harman, Donna

    2011-01-01

    Evaluation has always played a major role in information retrieval, with the early pioneers such as Cyril Cleverdon and Gerard Salton laying the foundations for most of the evaluation methodologies in use today. The retrieval community has been extremely fortunate to have such a well-grounded evaluation paradigm during a period when most of the human language technologies were just developing. This lecture has the goal of explaining where these evaluation methodologies came from and how they have continued to adapt to the vastly changed environment in the search engine world today. The lecture

  7. OXYGEN ABUNDANCES IN CEPHEIDS

    Energy Technology Data Exchange (ETDEWEB)

    Luck, R. E.; Andrievsky, S. M. [Department of Astronomy, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7215 (United States); Korotin, S. N.; Kovtyukh, V. V., E-mail: luck@fafnir.astr.cwru.edu, E-mail: serkor@skyline.od.ua, E-mail: val@deneb1.odessa.ua, E-mail: scan@deneb1.odessa.ua [Department of Astronomy and Astronomical Observatory, Odessa National University, Isaac Newton Institute of Chile, Odessa Branch, Shevchenko Park, 65014 Odessa (Ukraine)

    2013-07-01

    Oxygen abundances in later-type stars, and intermediate-mass stars in particular, are usually determined from the [O I] line at 630.0 nm, and to a lesser extent, from the O I triplet at 615.7 nm. The near-IR triplets at 777.4 nm and 844.6 nm are strong in these stars and generally do not suffer from severe blending with other species. However, these latter two triplets suffer from strong non-local thermodynamic equilibrium (NLTE) effects and thus see limited use in abundance analyses. In this paper, we derive oxygen abundances in a large sample of Cepheids using the near-IR triplets from an NLTE analysis, and compare those abundances to values derived from a local thermodynamic equilibrium (LTE) analysis of the [O I] 630.0 nm line and the O I 615.7 nm triplet as well as LTE abundances for the 777.4 nm triplet. All of these lines suffer from line strength problems making them sensitive to either measurement complications (weak lines) or to line saturation difficulties (strong lines). Upon this realization, the LTE results for the [O I] lines and the O I 615.7 nm triplet are in adequate agreement with the abundance from the NLTE analysis of the near-IR triplets.

  8. 基于 CART 决策树方法的 MODIS 数据海冰反演%Retrieval of the sea ice area from MODIS data by CART decision tree method

    Institute of Scientific and Technical Information of China (English)

    张娜; 张庆河

    2014-01-01

    The methodology of CART decision tree is utilized to retrieve the sea ice area from MODIS satellite remote sensing data, which realizes the automatic classification by multi -bands of visible light, near infrared light and thermal infrared light, and effectively eliminates the misjudgment by traditional threshold methods when retrieving sea ice in the marine environment such as high sediment suspension. The retrieved results are verified by the Small Satellite Constellation for Environment and Disaster Monitoring and Forecasting (HJ-1A/1B) with the high spatial resolution,which suggests that the retrieved data based on the CART decision tree have the higher resolution. The process of sea ice growing and melting in the Liaodong Bay during winter since 2003 is retrieved by this methodology, which provides precise and reliable data for analyzing the relationship between meteorologic factor and sea ice evolution.%采用 CART 决策树方法从 MODIS 卫星遥感数据反演海冰面积,同时对可见光、近红外和热红外多波段进行自动分类计算,有效消除了传统阈值法在反演高悬沙等海洋环境时出现的海冰误判。经较高分辨率的中国环境与灾害监测预报小卫星(HJ-1A/1B)校验,结果表明基于决策树方法所得出的反演数据具有较高精度。利用建立的 CART 决策树方法反演了2003年以来辽东湾冬季海冰面积的生消变化过程,为进一步分析和建立气象因素与海冰演化规律的关系提供了精确可靠的基础资料。

  9. An image retrieval method based on a convolutional neural network and hash coding%基于卷积神经网络和哈希编码的图像检索方法

    Institute of Scientific and Technical Information of China (English)

    龚震霆; 陈光喜; 任夏荔; 曹建收

    2016-01-01

    在图像检索中,传统的基于人工特征的检索方法并不能取得很好的效果。为此提出一种结合卷积神经网络和以前最好水准的哈希编码策略的图像检索方法。鉴于近几年卷积神经网络在大量的计算机视觉任务上的巨大进步,该方法首先使用在ILSVRC数据集上预训练过的VGGNet-D网络模型对实验图像数据集提取卷积特征来得到图像的深层表示,再采用以前最好水准的哈希策略将这些深层表示进行编码,从而得到图像的二进制码,最后再进行快速图像检索。在两个常用的数据集Caltech101和Caltech256上的实验结果表明,本文方法的5个策略相比于以前最好水准的相应的图像检索策略在“精度-召回率”和“平均正确率值-编码位数”两个指标上能获得更优异的性能,证明了本文方法在图像检索上的有效性。%For image retrieval, traditional retrieval methods based on artificial features are not effective enough. Hence, we propose an image retrieval method, which combines a convolutional neural network and previous state⁃of⁃the⁃art hash coding strategies. In view of the great progress that convolutional neural networks have made in a large number of computer vision tasks in recent years, this method first uses the model"VGGNet⁃D" pre⁃trained on the ILSVRC′s dataset to extract the convolutional features from experimental image datasets to get the deep repre⁃sentations of images, then adopts previous state⁃of⁃the⁃art hash coding strategies to encode the deep representations to obtain the binary codes, and, finally, performs a quick image retrieval. The experimental results on the common⁃ly used Caltech101 and Caltech256 datasets show that this method′s five strategies, compared with the previous state⁃of⁃the⁃art image retrieval strategies, can obtain better, indeed excellent, performance in both the"Precision⁃Recall" and"mean Average

  10. The Knowledge Retrieval Matrix

    DEFF Research Database (Denmark)

    Gammelgaard, Jens; Ritter, Thomas

    2004-01-01

    AbstractPrevious discussions of knowledge transfer within multinational corporations tended tofocus on the process as an isolated phenomenon and on the factors that impede the process.Less attention has been given to how the individual knowledge worker retrieves or identifies,and then decodes...

  11. Information Retrieval Models

    NARCIS (Netherlands)

    Hiemstra, Djoerd; Göker, Ayse; Davies, John

    2009-01-01

    Many applications that handle information on the internet would be completely inadequate without the support of information retrieval technology. How would we find information on the world wide web if there were no web search engines? How would we manage our email without spam filtering? Much of the

  12. Music Information Retrieval.

    Science.gov (United States)

    Downie, J. Stephen

    2003-01-01

    Identifies MIR (Music Information Retrieval) computer system problems, historic influences, current state-of-the-art, and future MIR solutions through an examination of the multidisciplinary approach to MIR. Highlights include pitch; temporal factors; harmonics; tone; editorial, textual, and bibliographic facets; multicultural factors; locating…

  13. Practical Online Retrieval Evaluation

    NARCIS (Netherlands)

    Radlinski, F.; Hofmann, K.

    2013-01-01

    Online evaluation allows the assessment of information retrieval (IR) techniques based on how real users respond to them. Because this technique is directly based on observed user behavior, it is a promising alternative to traditional offline evaluation, which is based on manual relevance assessment

  14. Atmospheric Retrievals from Exoplanet Observations and Simulations with BART

    Science.gov (United States)

    Harrington, Joseph

    This project will determine the observing plans needed to retrieve exoplanet atmospheric composition and thermal profiles over a broad range of planets, stars, instruments, and observing modes. Characterizing exoplanets is hard. The dim planets orbit bright stars, giving orders of magnitude more relative noise than for solar-system planets. Advanced statistical techniques are needed to determine what the data can - and more importantly cannot - say. We therefore developed Bayesian Atmospheric Radiative Transfer (BART). BART explores the parameter space of atmospheric chemical abundances and thermal profiles using Differential-Evolution Markov-Chain Monte Carlo. It generates thousands of candidate spectra, integrates over observational bandpasses, and compares to data, generating a statistical model for an atmosphere's composition and thermal structure. At best, it gives abundances and thermal profiles with uncertainties. At worst, it shows what kinds of planets the data allow. It also gives parameter correlations. BART is open-source, designed for community use and extension (http://github.com/exosports/BART). Three arXived PhD theses (papers in publication) provide technical documentation, tests, and application to Spitzer and HST data. There are detailed user and programmer manuals and community support forums. Exoplanet analysis techniques must be tested against synthetic data, where the answer is known, and vetted by statisticians. Unfortunately, this has rarely been done, and never sufficiently. Several recent papers question the entire body of Spitzer exoplanet observations, because different analyses of the same data give different results. The latest method, pixel-level decorrelation, produces results that diverge from an emerging consensus. We do not know the retrieval problem's strengths and weaknesses relative to low SNR, red noise, low resolution, instrument systematics, or incomplete spectral line lists. In observing eclipses and transits, we assume

  15. Retrieval of ash properties from IASI measurements

    Science.gov (United States)

    Ventress, Lucy J.; McGarragh, Gregory; Carboni, Elisa; Smith, Andrew J.; Grainger, Roy G.

    2016-11-01

    A new optimal estimation algorithm for the retrieval of volcanic ash properties has been developed for use with the Infrared Atmospheric Sounding Interferometer (IASI). The retrieval method uses the wave number range 680-1200 cm-1, which contains window channels, the CO2 ν2 band (used for the height retrieval), and the O3 ν3 band.Assuming a single infinitely (geometrically) thin ash plume and combining this with the output from the radiative transfer model RTTOV, the retrieval algorithm produces the most probable values for the ash optical depth (AOD), particle effective radius, plume top height, and effective radiating temperature. A comprehensive uncertainty budget is obtained for each pixel. Improvements to the algorithm through the use of different measurement error covariance matrices are explored, comparing the results from a sensitivity study of the retrieval process using covariance matrices trained on either clear-sky or cloudy scenes. The result showed that, due to the smaller variance contained within it, the clear-sky covariance matrix is preferable. However, if the retrieval fails to pass the quality control tests, the cloudy covariance matrix is implemented.The retrieval algorithm is applied to scenes from the Eyjafjallajökull eruption in 2010, and the retrieved parameters are compared to ancillary data sources. The ash optical depth gives a root mean square error (RMSE) difference of 0.46 when compared to retrievals from the MODerate-resolution Imaging Spectroradiometer (MODIS) instrument for all pixels and an improved RMSE of 0.2 for low optical depths (AOD < 0.1). Measurements from the Facility for Airborne Atmospheric Measurements (FAAM) and Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) flight campaigns are used to verify the retrieved particle effective radius, with the retrieved distribution of sizes for the scene showing excellent consistency. Further, the plume top altitudes are compared to derived cloud-top altitudes from the Cloud

  16. Phase retrieval with prior information.

    Science.gov (United States)

    Irwan, R; Lane, R G

    1998-09-01

    An algorithm for phase retrieval with Bayesian statistics is discussed. It is shown how the statistics of Kolmogorov turbulence can be used to compute the likelihood for a particular phase screen. This likelihood is then added to that of the observed data to produce a functional that is maximized directly by use of conjugate gradient maximization. It is shown that although this can significantly improve the quality of the phase estimate,the issue is complicated by local maxima introduced by the possibility of phase wrapping. The causes of the local maxima are analyzed, and a method that increases the likelihood of convergence to the global maximum is presented.

  17. Video Retrieval Method Based on Spatio-temporal Feature and Key Frames%融合时序特征和关键帧的视频检索方法

    Institute of Scientific and Technical Information of China (English)

    陈秀新; 贾克斌; 邓智玭

    2011-01-01

    针对已有视频检索方法存在的诸多问题,提出了一种融合视频时序特征和关键帧的视频检索方法.该方法首先提取视频的时序特征,通过匹配两段视频的时序特征可直接实现画面变化率高的视频(如广告等)的检索,大大减小了视频检索的运算量.在此基础上,对于画面内容变化率较低的视频(如电视剧等),进一步将其划分为若干个子片段,每个子片段中提取出关键帧用于检索.实验结果表明,该方法检索效果好,稳健性高,应用范围广.%To solve the problems of present video retrieval algorithms, a video retrieval method base on video spatio-temporal feature curves and key frames is proposed. First, the feature curves are extracted, and then two videos' feature curves are compared to determine whether they have the same content. Based on the retrieval results, for a video whose content does not change frequently, the video is further divided to several clips. Key frames are selected from each of the clips and are used to compare with those of another video. Experiments show that the method is very effective, robust to various disturbances and can be used for various types of videos.

  18. Phase retrieval by coherent modulation imaging

    Science.gov (United States)

    Zhang, Fucai; Chen, Bo; Morrison, Graeme R.; Vila-Comamala, Joan; Guizar-Sicairos, Manuel; Robinson, Ian K.

    2016-01-01

    Phase retrieval is a long-standing problem in imaging when only the intensity of the wavefield can be recorded. Coherent diffraction imaging is a lensless technique that uses iterative algorithms to recover amplitude and phase contrast images from diffraction intensity data. For general samples, phase retrieval from a single-diffraction pattern has been an algorithmic and experimental challenge. Here we report a method of phase retrieval that uses a known modulation of the sample exit wave. This coherent modulation imaging method removes inherent ambiguities of coherent diffraction imaging and uses a reliable, rapidly converging iterative algorithm involving three planes. It works for extended samples, does not require tight support for convergence and relaxes dynamic range requirements on the detector. Coherent modulation imaging provides a robust method for imaging in materials and biological science, while its single-shot capability will benefit the investigation of dynamical processes with pulsed sources, such as X-ray free-electron lasers. PMID:27857061

  19. Phase retrieval by coherent modulation imaging

    Science.gov (United States)

    Zhang, Fucai; Chen, Bo; Morrison, Graeme R.; Vila-Comamala, Joan; Guizar-Sicairos, Manuel; Robinson, Ian K.

    2016-11-01

    Phase retrieval is a long-standing problem in imaging when only the intensity of the wavefield can be recorded. Coherent diffraction imaging is a lensless technique that uses iterative algorithms to recover amplitude and phase contrast images from diffraction intensity data. For general samples, phase retrieval from a single-diffraction pattern has been an algorithmic and experimental challenge. Here we report a method of phase retrieval that uses a known modulation of the sample exit wave. This coherent modulation imaging method removes inherent ambiguities of coherent diffraction imaging and uses a reliable, rapidly converging iterative algorithm involving three planes. It works for extended samples, does not require tight support for convergence and relaxes dynamic range requirements on the detector. Coherent modulation imaging provides a robust method for imaging in materials and biological science, while its single-shot capability will benefit the investigation of dynamical processes with pulsed sources, such as X-ray free-electron lasers.

  20. A review of iterative phase retrieval for measurement and encryption

    Science.gov (United States)

    Guo, Cheng; Wei, Ce; Tan, Jiubin; Chen, Kana; Liu, Shutian; Wu, Qun; Liu, Zhengjun

    2017-02-01

    Phase retrieval technique is regarded as one of the most significant tools to solve optical inverse problems. Several phase retrieval algorithms are discussed in this review. The occurrence of ill-posed conditions often makes the calculation difficult. As a synthesis, the multiple-image phase retrieval technology is invented to obtain more accurate convergence result in iterative computation. The multiple-input retrieval scheme can attach new constraints on convergence as a new limitation. As an indirect measuring method, it will make it possible to reconstruct the distribution of intensity and phase in an imaging or measurement system, where data processing is executed by computer. Moreover, the retrieval method has been applied for image encryption successfully. Finally, the development and application of the iterative phase retrieval are overviewed.

  1. Glyoxal Retrieval from the Ozone Monitoring Instrument

    Science.gov (United States)

    Miller, C. E.; Jacob, D. J.; Gonzalez Abad, G.; Wang, H.; Liu, X.; Chance, K.

    2014-12-01

    We have developed an improved algorithm for the retrieval of glyoxal (CHOCHO) from OMI. Glyoxal is a short-lived product of volatile organic carbon (VOC) oxidation. Satellite glyoxal observations may provide a powerful addition to existing formaldehyde products for constraining VOC emissions. However, glyoxal-to-formaldehyde ratios of current retrievals disagree with ground-based observations over anthropogenic and biogenic regions, inhibiting their combined use in top-down studies. To address these discrepancies we perform a series of sensitivity studies on real and simulated OMI spectra. We show that the sensitive fit window dependence found in previous studies is consistent with a combination of errors from reference cross section uncertainties and spectral interference due to the Ring effect. This implies an optimal fit window of 435-461 nm, consistent with previous retrievals. Using simulated spectra we confirm a NO2 interference associated with cross section temperature, that can be corrected using multiple cross sections. We show that cross-track biases in the OMI retrieval can be corrected by deriving offsets over the Sahara, and apply the correction to the OMI data. Average background concentrations are lower in the new product since the Sahara reference sector is free of liquid water interference associated with the oceanic regions used in previous studies. Concentrations measured over Asia during the monsoon season and the tropics are also lower, suggesting that the new retrieval is less sensitive to water vapor abundance. Consequently we do not see significant enhancements over tropical oceans. The glyoxal-to-formaldehyde ratios of the new OMI product are consistent with surface observations.

  2. Improving Performance Support Systems through Information Retrieval Evaluation

    Science.gov (United States)

    Schatz, Steven

    2006-01-01

    This study examines existent and new methods for evaluating the success of information retrieval systems. The theory underlying current methods is not robust enough to allow testing retrieval using different meta-tagging schema's. Traditional measures rely on judgments of whether a document is relevant to a particular question. A good system…

  3. Source code retrieval using conceptual similarity

    NARCIS (Netherlands)

    Mishne, G.A.; de Rijke, M.

    2004-01-01

    We propose a method for retrieving segments of source code from a large repository. The method is based on conceptual modeling of the code, combining information extracted from the structure of the code and standard informationdistance measures. Our results show an improvement over traditional retri

  4. Iterative Algorithms for Ptychographic Phase Retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chao; Qian, Jianliang; Schirotzek, Andre; Maia, Filipe; Marchesini, Stefano

    2011-05-03

    Ptychography promises diffraction limited resolution without the need for high resolution lenses. To achieve high resolution one has to solve the phase problem for many partially overlapping frames. Here we review some of the existing methods for solving ptychographic phase retrieval problem from a numerical analysis point of view, and propose alternative methods based on numerical optimization.

  5. A Full-text Retrieval Method for Spatial Data Search Based on Global Subdivision Grid%基于全球剖分网格的空间数据全文检索方法

    Institute of Scientific and Technical Information of China (English)

    褚福林; 濮国梁; 程承旗; 冯洋

    2015-01-01

    目前,国内外不同部门的空间数据管理系统彼此独立,数据共享检索效率低。针对此问题,本文提出了一种基于全球剖分网格的空间数据全文检索方法。该方法描述了基于全球剖分网格原理,根据地理空间实体的区位信息建立全球唯一的空间区位标识编码,通过全文索引引擎对空间区位标识编码建立全文索引,实现对地理空间数据的检索。通过对比试验可知,在大数据量的时候,基于全球剖分网格的空间数据全文检索方法比基于B+树的传统关系型数据库检索效率高,在海量空间数据的检索上具有一定应用价值。%At present, different departments have different spatial data management systems, which leads to low efficiency of data sharing. To solve this problem, a full-text retrieval method for spatial data based on global subdivision grid is put forward. Under the global subdivision grid system, each geospatial entity can be identified by a globally unique spatial location code according to its location information, so that spatial data can be retrieved efficiently using the full-text indexing engine by the location code. By comparison experiments under large amount of data, the full-text retrieval method based on global subdivision grid has higher efficiency than RDBMS based on B+-tree, which has certain value in massive spatial data retrieval application.

  6. A Visual Information Retrieval Tool.

    Science.gov (United States)

    Zhang, Jin

    2000-01-01

    Discussion of visualization for information retrieval, that transforms unseen internal semantic representation of a document collection into visible geometric displays, focuses on DARE (Distance Angle Retrieval Environment). Highlights include expression of information need; interpretation and manipulation of information retrieval models; ranking…

  7. Abundance estimation and Conservation Biology

    Directory of Open Access Journals (Sweden)

    Nichols, J. D.

    2004-06-01

    our attention should be focused on relationships between demographic processes such as survival and recruitment, the two quantities responsible for changes in abundance, rather than simply on the magnitudes of these quantities. They describe a type of Jolly–Seber capture–recapture model that permits inference about the underlying relationship between per capita recruitment rates and survival rates (Link & Barker, this volume. Implementation used Bayesian Markov Chain Monte Carlo methods and appeared to work well, yielding inferences about the relationship between recruitment and survival that were robust to selection of prior distribution. We believe that readers will find their arguments compelling, and we expect to see increased use of hierarchical modeling approaches in capture–recapture and related fields. Otto (presentation without paper also recommended use of hierarchical models in analysis of multiple data sources dealing with population dynamics of North American mallards. He integrated survival inferences from ringing data, abundance information from aerial survey data, and recruitment information based on age ratios from a harvest survey. He used a Leslie matrix population projection model as an integrating framework and obtained estimates of breeding population size using all data.Otto’s approach also permitted inference about biases in estimated quantities. As with the work of Link & Barker (2004, we find Otto’s recommendation to use hierarchical models to integrate data from multiple sources to be very compelling. Alisauskas et al. (2004 report results of an analysis of capture–recapture data for a askatchewan population of white–winged scoters. They used the approach of Pradel (1996 to estimate population growth rate (See the PDF directly. Estimates for 1975–1985 were quite low, but estimates for the recent period, 2000–2003,increased to values > 1. Parameter estimates for seniority, survival and per capita recruitment (Pradel, 1996

  8. Abundance estimation and conservation biology

    Science.gov (United States)

    Nichols, J.D.; MacKenzie, D.I.

    2004-01-01

    should be focused on relationships between demographic processes such as survival and recruitment, the two quantities responsible for changes in abundance, rather than simply on the magnitudes of these quantities. They describe a type of Jolly–Seber capture–recapture model that permits inference about the underlying relationship between per capita recruitment rates and survival rates (Link & Barker, this volume). Implementation used Bayesian Markov Chain Monte Carlo methods and appeared to work well, yielding inferences about the relationship between recruitment and survival that were robust to selection of prior distribution. We believe that readers will find their arguments compelling, and we expect to see increased use of hierarchical modeling approaches in capture–recapture and related fields. Otto (presentation without paper) also recommended use of hierarchical models in analysis of multiple data sources dealing with population dynamics of North American mallards. He integrated survival inferences from ringing data, abundance information from aerial survey data, and recruitment information based on age ratios from a harvest survey. He used a Leslie matrix population projection model as an integrating framework and obtained estimates of breeding population size using all data.Otto’s approach also permitted inference about biases in estimated quantities. As with the work of Link & Barker (2004), we find Otto’s recommendation to use hierarchical models to integrate data from multiple sources to be very compelling. Alisauskas et al. (2004) report results of an analysis of capture–recapture data for a askatchewan population of white–winged scoters. They used the approach of Pradel (1996) to estimate population growth rate (See the PDF) directly. Estimates for 1975–1985 were quite low, but estimates for the recent period, 2000–2003,increased to values > 1. Parameter estimates for seniority, survival and per capita recruitment (Pradel, 1996) led to the

  9. Simulated Radiative Transfer DOAS - A new method for improving volcanic SO2 emissions retrievals from ground-based UV-spectroscopic measurements of scattered solar radiation

    Science.gov (United States)

    Kern, C.; Deutschmann, T.; Vogel, L.; Bobrowski, N.; Hoermann, C.; Werner, C. A.; Sutton, A. J.; Elias, T.

    2011-12-01

    Passive Differential Optical Absorption Spectroscopy (DOAS) has become a standard tool for measuring SO2 at volcanoes. More recently, ultra-violet (UV) cameras have also been applied to obtain 2D images of SO2-bearing plumes. Both techniques can be used to derive SO2 emission rates by measuring SO2 column densities, integrating these along the plume cross-section, and multiplying by the wind speed. Recent measurements and model studies have revealed that the dominating source of uncertainty in these techniques often originates from an inaccurate assessment of radiative transfer through the volcanic plume. The typical assumption that all detected radiation is scattered behind the volcanic plume and takes a straight path from there to the instrument is often incorrect. We recently showed that the straight path assumption can lead to column density errors of 50% or more in cases where plumes with high SO2 and aerosol concentrations are measured from several kilometers distance, or where the background atmosphere contains a large amount of scattering aerosols. Both under- and overestimation are possible depending on the atmospheric conditions and geometry during spectral acquisition. Simulated Radiative Transfer (SRT) DOAS is a new evaluation scheme that combines radiative transfer modeling with spectral analysis of passive DOAS measurements in the UV region to derive more accurate SO2 column densities than conventional DOAS retrievals, which in turn leads to considerably more accurate emission rates. A three-dimensional backward Monte Carlo radiative transfer model is used to simulate realistic light paths in and around the volcanic plume containing variable amounts of SO2 and aerosols. An inversion algorithm is then applied to derive the true SO2 column density. For fast processing of large datasets, a linearized algorithm based on lookup tables was developed and tested on a number of example datasets. In some cases, the information content of the spectral data is

  10. Semantic-Aware Co-Indexing for Image Retrieval.

    Science.gov (United States)

    Zhang, Shiliang; Yang, Ming; Wang, Xiaoyu; Lin, Yuanqing; Tian, Qi

    2015-12-01

    In content-based image retrieval, inverted indexes allow fast access to database images and summarize all knowledge about the database. Indexing multiple clues of image contents allows retrieval algorithms search for relevant images from different perspectives, which is appealing to deliver satisfactory user experiences. However, when incorporating diverse image features during online retrieval, it is challenging to ensure retrieval efficiency and scalability. In this paper, for large-scale image retrieval, we propose a semantic-aware co-indexing algorithm to jointly embed two strong cues into the inverted indexes: 1) local invariant features that are robust to delineate low-level image contents, and 2) semantic attributes from large-scale object recognition that may reveal image semantic meanings. Specifically, for an initial set of inverted indexes of local features, we utilize semantic attributes to filter out isolated images and insert semantically similar images to this initial set. Encoding these two distinct and complementary cues together effectively enhances the discriminative capability of inverted indexes. Such co-indexing operations are totally off-line and introduce small computation overhead to online retrieval, because only local features but no semantic attributes are employed for the query. Hence, this co-indexing is different from existing image retrieval methods fusing multiple features or retrieval results. Extensive experiments and comparisons with recent retrieval methods manifest the competitive performance of our method.

  11. Endoscopic retrieval of gastric trichophytobezoar

    Science.gov (United States)

    Zhao, Jiu-ling; Zhao, Wei-chuan; Wang, Yu-shui

    2017-01-01

    Abstract Rationale: Trichophytobezoars, which are composed of hair and plant fibers, are usually located in the stomach. They are often associated with trichophagia and trichotillomania. The most commonly reported methods of trichophytobezoar treatment are open surgery and laparoscopic retrieval; there are few reports of endoscopic removal of trichophytobezoars. Patient concerns and Diagnoses: Twelve-year-old girl presented with a 3-day history of increasing upper abdominal pain, anorexia, and postprandial emesis. She had a 3-year history of pulling out and eating her own hair. Endoscopic examination showed a large intragastric trichophytobezoar measuring 10.5 cm × 3.5 cm in size, with extension of a few hairs through the pylorus. Interventions and Outcomes: The trichophytobezoar was packed with hair fibers and contained a hard core of mixed hair and vegetable fibers. After the core was cut, the trichophytobezoar was fragmented into pieces with the alternating use of a polypectomy snare and argon plasma coagulation. A small amount of hair and nondigestible food fibers was removed with grasping forceps during the initial procedure. The remaining hairball was loosened with biopsy forceps and was injected with sodium bicarbonate solution. The trichophytobezoar was removed completely at repeat endoscopy 5 days later. After 6 months of psychological intervention, the patient had no recurrence of trichophagia or trichophytobezoar. Lessons: Endoscopy with sodium bicarbonate injection is an effective and minimally invasive method of retrieving a gastric trichophytobezoar. PMID:28099364

  12. DOLPHIn—Dictionary Learning for Phase Retrieval

    Science.gov (United States)

    Tillmann, Andreas M.; Eldar, Yonina C.; Mairal, Julien

    2016-12-01

    We propose a new algorithm to learn a dictionary for reconstructing and sparsely encoding signals from measurements without phase. Specifically, we consider the task of estimating a two-dimensional image from squared-magnitude measurements of a complex-valued linear transformation of the original image. Several recent phase retrieval algorithms exploit underlying sparsity of the unknown signal in order to improve recovery performance. In this work, we consider such a sparse signal prior in the context of phase retrieval, when the sparsifying dictionary is not known in advance. Our algorithm jointly reconstructs the unknown signal - possibly corrupted by noise - and learns a dictionary such that each patch of the estimated image can be sparsely represented. Numerical experiments demonstrate that our approach can obtain significantly better reconstructions for phase retrieval problems with noise than methods that cannot exploit such "hidden" sparsity. Moreover, on the theoretical side, we provide a convergence result for our method.

  13. Deuterium abundance and cosmology

    CERN Document Server

    Vidal-Madjar, A; Lemoine, M

    1996-01-01

    We review the status of the measurements of the deuterium abundance from the local interstellar medium to the solar system and high redshifts absorbers toward quasars. We present preliminary results toward a white dwarf and a QSO. We conclude that the deuterium evolution from the Big-Bang to now is still not properly understood.

  14. Sm Transition Probabilities and Abundances

    CERN Document Server

    Lawler, J E; Sneden, C; Cowan, J J

    2005-01-01

    Radiative lifetimes, accurate to +/- 5%, have been measured for 212 odd-parity levels of Sm II using laser-induced fluorescence. The lifetimes are combined with branching fractions measured using Fourier-transform spectrometry to determine transition probabilities for more than 900 lines of Sm II. This work is the largest-scale laboratory study to date of Sm II transition probabilities using modern methods. This improved data set has been used to determine a new solar photospheric Sm abundance, log epsilon = 1.00 +/- 0.03, from 26 lines. The spectra of three very metal-poor, neutron-capture-rich stars also have been analyzed, employing between 55 and 72 Sm II lines per star. The abundance ratios of Sm relative to other rare earth elements in these stars are in agreement, and are consistent with ratios expected from rapid neutron-capture nucleosynthesis (the r-process).

  15. New method of sea surface wind speed retrieval using genetic algorithms and neural network%基于遗传神经网络算法的海面风速反演新方法

    Institute of Scientific and Technical Information of China (English)

    石汉青; 张雷; 杜华栋; 龙智勇; 姜世泰

    2013-01-01

    There exist the complexity of sea surface and the limitation of theoretical model of electromagnet-ic scattering,and nonlinear phenomena in the retrieval of sea surface wind speed,which is based on syn-thetic aperture radar (SAR)images.With the method of genetic neural network and Fletcher-Reeves,this paper established a new model of retrieving wind speed based on operational data of CMOD4 model func-tion.The result shows that this model is available in retrieving ocean surface wind.When random error is less than 10%,this model has high denoising ability and the accuracy of the retrieved ocean surface wind speed is ideal.Comparing the results of different wind speed,shows that in the case of low or middle wind,the fitness of learning model and the accuracy of predicted tests have both ideal accuracy,and that in the case of strong wind,the inversion result of this model is comparatively poor.%针对海面运动的复杂性、海面电磁散射理论模型的局限性以及利用 SAR 图像反演海面风速存在的非线性现象,基于遗传神经网络的方法,以业务化的 CMOD4模式函数数据为基础,采用 Fletcher-Reeves 算法的变梯度反向传播算法,建立一种 SAR 风速反演的新模型。试验结果表明,利用遗传神经网络方法反演海面风速是可行的,当随机误差小于10%时,模型的抗噪能力较强,风速反演的精度较为理想。比较不同风速下的反演结果可以发现,在中、小风速的情况下,模型的抗噪能力较强,模型学习拟合和预测检验的精度相对较高;在大风速的情况下,模型的反演能力有待于进一步提高。

  16. 体外受精取卵日手淫取精失败的取精方法%Research on methods to obtain sperm after failing to obtain sperm by masturbation in oocyte retrieval for in vitro fertilization

    Institute of Scientific and Technical Information of China (English)

    蒲军; 丘彦

    2011-01-01

    目的 研究体外受精取卵日手淫取精失败的取精方法.方法 对120例体外受精取卵日手淫取精失败的临床资料进行回顾分析.结果 120例患者分别采用药物治疗法、性交法、阴茎头震荡刺激法、经直肠输精管壶腹和精囊及前列腺按摩法、经皮穿刺附睾睾丸法5种方法作为手淫取精失败的替代取精法,120例患者全部取精成功.结论 性交法、经皮穿刺附睾睾丸取精法是较满意的两种替代方法.提前冷冻精子是解决体外受精取卵日手淫取精失败的最佳方案.%Objective To research the methods to obtain sperm after failing to obtain sperm by masturbation in oocyte retrieval for in vitro fertilization. Methods To retrospectively analyse the clinical data of 120 patients failing to obtain sperm by masturbation in oocyte retrieval for in vitro fertilization. Results 120 patients adopted 5 methods respectively to obtain sperm for substitution,which including drug treatment,coitus,shaking and stimulating balanus,pressing ampulla of deferent duct and seminal vesicle and prostate per rectum, percutaneous epididymal and testicular sperm aspiration. Conclusion There are two frequently used methods to obtain sperm by coitus and percutaneous epididymal and testicular sperm aspiration for substitution. It is the optimal method to freeze sperm in advance to deal with one patient fail to obtain sperm by masturbation in oocyte retrieval for in vitro fertilization.

  17. Image retrieval using both color and texture features

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In order to improve the retrieval performance of images, this paper proposes an efficient approach for extracting and retrieving color images. The block diagram of our proposed approach to content-based image retrieval (CBIR) is given firstly, and then we introduce three image feature extracting arithmetic including color histogram, edge histogram and edge direction histogram, the histogram Euclidean distance, cosine distance and histogram intersection are used to measure the image level similarity. On the basis of using color and texture features separately, a new method for image retrieval using combined features is proposed. With the test for an image database including 766 general-purpose images and comparison and analysis of performance evaluation for features and similarity measures, our proposed retrieval approach demonstrates a promising performance. Experiment shows that combined features are superior to every single one of the three features in retrieval.

  18. A Survey on the Image Retrieval via Site Operator

    Directory of Open Access Journals (Sweden)

    Saleh Rahimi

    2015-12-01

    Full Text Available The purpose of the present study is to investigate the Impact of Image Indexing on Optimizing Image Retrieval via site operator. Using quasi-experimental method 100 images, each image was uploaded 9 times with concept-based characteristics on iiproject.ir. Analysis consists of images which retrieved from the site operator. Number of images retrieved by the site operator is 151 images of 900 ones that are used in this study. The minimum number of retrieved images is related to "image titles" and the maximum ones to the criteria images which entitled with Q code. Chi-square statistics showed that the number of images retrieved in various codes was different. The best ranking is related to “image title” and the weakest one related to “image caption in Farsi”. Images average ranking retrieved in 9 groups were different.

  19. Wind vector retrieval using dual polarization imagery of ASAR

    Institute of Scientific and Technical Information of China (English)

    SONG Guiting; HOU Yijun; QI Peng

    2006-01-01

    A new algorithm for retrieving wind vector using dual polarization imagery of advanced synthetic aperture radar (ASAR) is developed and tested. Based on the combination of co-polarization and cross-polarization, this new algorithm effectively eliminates the 180° ambiguity which occurs when using single imagery of the ASAR to retrieve wind vector. This algorithm also solves the problem that the retrieval results will break down on very small spatial scales. The results retrieved from dual polarization imagery of ASAR show that the wind speed and direction are in agreement with the data from Quikscat and buoy measurements. The root mean square errors of wind direction and speed between the retrieved results and data from Quikscat are 2.21° and 0.53 m/s, respectively.Comparisons between the new method and the traditional method show that the new methods fit the buoy data and Quikscat data a little better than the traditional method in this image.

  20. Use of Multiple Methods to Estimate Walrus (Odobenus rosmarus rosmarus Abundance in the Penny Strait-Lancaster Sound and West Jones Sound Stocks, Canada

    Directory of Open Access Journals (Sweden)

    Robert EA Stewart

    2014-12-01

    Full Text Available Surveys to estimate walrus abundance at terrestrial haulout sites in the Penny Strait-Lancaster Sound (PS-LS and West Jones Sound (WJS stocks were conducted in 1977 and 1998-2009. The Minimum Counted Population (MCP was similar in 1977 (565 to recent years (557 for the PS-LS stock. The MCP for the WJS stock was higher in recent surveys (404 than in 1977 (290. Regression analysis of MCP and density (number of walrus divided by number of haulouts surveyed showed no significant trends over time. We also calculated bounded count estimates for comparison. Finally, we used broad-scale behavioural data to estimate the proportion of the total stock that could be considered countable, to produce two adjusted estimates. We selected recent surveys with good coverage and ignored adjusted estimates that were lower than MCP. For the PS-LS stock, the adjusted MCP (with 95% CL was 672 (575-768 and 727 (623-831 walrus in 2007 and 2009, respectively. For WJS, the best estimates were the adjusted MCP of 503 (473-534 in 2008 and the adjusted bounded count of 470 (297-1732 in 2009. While both stocks appear to have remained stable over three decades, differences in survey coverage and possible differences in walrus distribution make precise population estimation difficult.

  1. Abundance of 13C and 15N in emmer, spelt and naked barley grown on differently manured soils: towards a method for identifying past manuring practice

    DEFF Research Database (Denmark)

    Kanstrup, Marie; Thomsen, Ingrid Kaag; Andersen, Astrid Junker

    2011-01-01

    on the soil. We have examined the δ15N and δ13C values of soil and of the grain and straw fractions of three ancient cereal types grown in unmanured, PK amended and cattle manured plots of the Askov long-term field experiment. Manure increased biomass yields and the δ15N values of soil and of grain and straw...... fractions of the ancient cereal types; differences in δ15N between unmanured and PK treatments were insignificant. The offset in straw and grain δ15N due to manure averaged 7.9 and 8.8 ‰, respectively, while the soil offset was 1.9 ‰. The soil and biomass δ13C values were not affected by nutrient amendments...... a substantial positive effect on cereals grown in early agriculture and will have left a significant N isotopic imprint on soil, grains and straw. We suggest that the use of animal manure can be identified by the 15N abundance in remains of ancient cereals (e.g. charred grains) from archaeological sites...

  2. 大数据时代基于中文标记的图像视频综合检索方法研究%Method of image & video integrated retrieval based on Chinese marks in age of big data

    Institute of Scientific and Technical Information of China (English)

    张扬奇; 肖学福; 陈祥军; 刘金彪

    2013-01-01

    With pilot applications of various types of domestic IOT, cloud computation and other demonstration projects, humans entered the era of big data. The comprehensive application of image, video and other multimedias is the basic features of the big data. The image video retrieval technology based on OCR, image features and marks is researched. An integrated retrieval method of image resources in data center based on Chinese marks is proposed. It provided a reference for improvement of multimedia data availability of data center.%随着各类物联网、云计算等示范工程的试点应用,人类步入了大数据时代。图像、视频等多媒体综合应用是大数据时代的基本特征之一,文章综合研究了基于OCR、基于图像特征和基于标记的图像视频检索技术,提出了一种基于中文标记的数据中心视频图像资源综合检索方法,以期为提高数据中心多媒体数据的可用性提供借鉴。

  3. Immunohistochemical detection of disease-associated prion protein in the intestine of cattle naturally affected with bovine spongiform encephalopathy by using an alkaline-based chemical antigen retrieval method.

    Science.gov (United States)

    Okada, Hiroyuki; Iwamaru, Yoshihumi; Imamura, Morikazu; Masujin, Kentaro; Yokoyama, Takashi; Mohri, Shirou

    2010-11-01

    An alkaline-based chemical antigen retrieval pretreatment step was used to enhance immunolabeling of disease-associated prion protein (PrP(Sc)) in formalin-fixed and paraffin-embedded tissue sections from cattle naturally affected with bovine spongiform encephalopathy (BSE). The modified chemical method used in this study amplified the PrP(Sc) signal by unmasking PrP(Sc) compared with the normal cellular prion protein. In addition, this method reduced nonspecific background immunolabeling that resulted from the destruction of the residual normal cellular form of prion protein, and reduced the treatment time compared with the usual autoclave pretreatment step. Immunolabeled PrP(Sc) was thereby clearly detected in the myenteric plexus of the ileum in naturally occurring BSE cattle.

  4. Operation Optimization of Storage and Retrieval for Stackers Based on Nested Partitions Method%基于嵌套分区算法的堆垛机作业路径优化

    Institute of Scientific and Technical Information of China (English)

    李小笠; 刘桂芝; 杨文亮

    2012-01-01

    The operation optimization of storage and retrieval for stackers based on nested partitions method was researched. According to the advantage of nested partitions method which can effectively use the information itself, an optimized model aimed at minimum total operation time of stacker and well operation balance was present. For a specific AS/RS case, the comparison between pre-optimizing and after optimizing was carried out under the same parameters with simulation calculation. It is shown that the operation efficiency and precision of stacker which has less operation positions can be increased by means of the nested partitions method. The method has broad application prospect in the operation optimization of storage and retrieval for stackers in small AS/RS.%对嵌套分区算法在堆垛机作业路径优化问题中的应用展开研究.利用嵌套分区算法能有效利用问题本身信息的优点,对堆垛机单一出(入)库作业和入(出)库复合作业路径进行优化.通过计算机仿真证实:该算法对作业点较少的堆垛机路径优化问题有较高的优化精度和效率,特别是在小型立体仓库的堆垛机作业路径优化领域应用前景广阔.

  5. 冶金分析文献资源及检索方法%Literature resources and retrieval method of metallurgical analysis

    Institute of Scientific and Technical Information of China (English)

    邵梅; 闻向东

    2011-01-01

    The literatures are the basis of scientific researchers in conducting research. As there are lots of information and literatures related to metallurgical analysis on internet, how to rapidly and effectively acquire useful information has become a challenge for analysts. In this paper, the common literature resources about metallurgical analysis were classified. The main sources of literature information such as journals, works, patents, conferences, news, standardization information and laboratory management were introduced, as well as the comprehensive search resources at home and abroad.In addition, the retricval approaches and retrieval strategies of literature resourccs about metallurgical analysis were systemically discussed using "the determination of elements in ores hy inductively coupled plasma atomic emission spectrometry as an example.%文献资料是所有科研工作者开展工作的基础.由于网上冶金分析相关的信息和文献数量巨大,如何快速有效地获取有用信息成为一项具有挑战性的工作.本文对常用冶金分析文献资源进行了分类,分别对期刊、著作、专利、会议、新闻、标准化信息以及实验室管理信息等文献信息的主要来源以及国内外各种综合性搜索资源进行了介绍,并以电感耦合等离子体原子发射光谱法测定矿石中各种元素为例,就冶金分析文献的检索途径和检索策略进行了较为系统的探讨.

  6. Biomedical information retrieval across languages.

    Science.gov (United States)

    Daumke, Philipp; Markü, Kornél; Poprat, Michael; Schulz, Stefan; Klar, Rüdiger

    2007-06-01

    This work presents a new dictionary-based approach to biomedical cross-language information retrieval (CLIR) that addresses many of the general and domain-specific challenges in current CLIR research. Our method is based on a multilingual lexicon that was generated partly manually and partly automatically, and currently covers six European languages. It contains morphologically meaningful word fragments, termed subwords. Using subwords instead of entire words significantly reduces the number of lexical entries necessary to sufficiently cover a specific language and domain. Mediation between queries and documents is based on these subwords as well as on lists of word-n-grams that are generated from large monolingual corpora and constitute possible translation units. The translations are then sent to a standard Internet search engine. This process makes our approach an effective tool for searching the biomedical content of the World Wide Web in different languages. We evaluate this approach using the OHSUMED corpus, a large medical document collection, within a cross-language retrieval setting.

  7. Use of information-retrieval languages in automated retrieval of experimental data from long-term storage

    Science.gov (United States)

    Khovanskiy, Y. D.; Kremneva, N. I.

    1975-01-01

    Problems and methods are discussed of automating information retrieval operations in a data bank used for long term storage and retrieval of data from scientific experiments. Existing information retrieval languages are analyzed along with those being developed. The results of studies discussing the application of the descriptive 'Kristall' language used in the 'ASIOR' automated information retrieval system are presented. The development and use of a specialized language of the classification-descriptive type, using universal decimal classification indices as the main descriptors, is described.

  8. A novel mathematical formula for retrieval algorithm

    OpenAIRE

    2014-01-01

    A method is proposed to retrieve mathematical formula in LaTeX documents. Firstly, we represent the retrieved mathematical formula by binary tree according to its LaTeX description, normalize the structure of the binary tree, and obtain the structure code and then search the mathematical formula table that is named by the structure code and the formula elements of the first two levels of the binary tree in the mathematical formula database. If the table exists, then we search the normalizing ...

  9. A Image Denoising Method Based on Similar Image Retrieval and Dictionary Learning%基于相似图像检索与字典学习的图像去噪算法

    Institute of Scientific and Technical Information of China (English)

    胡占强; 耿龙

    2016-01-01

    In order to analyze and understand the image effectively, it's necessary to conduct denoising for image. Proposes a denoising method based on similar image retrieval and dictionary learning. Firstly, to have the better accuracy of image retrieval by improving noise signal ratio, denoising initially is executed for noise image; secondly, carry on image retrieval based on SIFT feature by using the initial noise image in the picture library and regard the similar image as a dictionary learning samples matched to improve correlation of dictionary and noise image; finally, the compensation of high frequency is needed. Satellite images are used to demonstrate the superiority of the proposed algorithm. Compared with the traditional denoising methods,the proposed method obtains better denoising effect,furthermore,it can effectively suppress the loss of high frequency information caused by the denoising procession.%为了更好地分析与理解图像,需对图像进行去噪。提出一种基于相似图像检索与字典学习的图像去噪方法。首先,为了提高图像检索的准确度,对噪声图像进行初始去噪提高信噪比;然后使用初始去噪图像在图片库里进行基于SIFT特征的图像检索,使用匹配到的相似图像作为字典学习的样本,提高字典与噪声图像的相关性;最后进行高频补偿。卫星图像被用于去噪实验证明所提算法的优越性。与传统去噪方法相比,所提出的方法不仅获得较好的去噪效果,而且在一定程度上有效地抑制去噪带来的高频信息丢失。

  10. Detecting Abundance Variations in Planetary Nebulae

    Science.gov (United States)

    Monteiro, H.; Santos, P. M.; Falceta-Gonçalves, D.

    2014-04-01

    Empirical methods of investigating chemical abundances are still widely used as a primary tool to study planetary nebulae (PNe) as well as HII regions. In this work we investigate the capacity of the empirical abundance determination methods to recover pre-defined parameters and abundance variations in a realistically modeled planetary nebula. To perform the test we use a threedimensional density structure obtained from a hydrodynamical simulation which is fed through a threedimensional photoionization code. The density structure is an asymetrical and inhomogeneous elongated closed shell. The input parameters used, such as, ionizing source, density, and chemical abundances are typical values of type I PNe. The model emissivities are then projected in the line of sight and emission line maps are generated, which are used to obtain the temperature and density diagnostics. The diagnostics and line emission maps are then used to obtain spatially resolved maps of the abundances. In this work we use the method described above to investigate abundances for two distinct orientations of the density structure. Our results show that for typical signal to noise ratios obtained from long-slit spectroscopy, only large abundance variations can be determined with good precision.

  11. Language-based multimedia information retrieval

    NARCIS (Netherlands)

    Jong, de F.M.G.; Gauvain, J.L.; Hiemstra, D.; Netter, K.

    2000-01-01

    This paper describes various methods and approaches for language-based multimedia information retrieval, which have been developed in the projects POP-EYE and OLIVE and which will be developed further in the MUMIS project. All of these project aim at supporting automated indexing of video material b

  12. Cross language information retrieval for biomedical literature

    NARCIS (Netherlands)

    Schuemie, M.; Trieschnigg, D.; Kraaij, W.

    2007-01-01

    This workshop report discusses the collaborative work of UT, EMC and TNO on the TREC Genomics Track 2007. The biomedical information retrieval task is approached using cross language methods, in which biomedical concept detection is combined with effective IR based on unigram language models. Furthe

  13. Result merging method based on combined kernels for distributed information retrieval%基于混合核函数的分布式信息检索结果融合

    Institute of Scientific and Technical Information of China (English)

    王秀红; 鞠时光

    2011-01-01

    To enhance the performance of result merging for distributed information retrieval (DIR), a novel merging method was put forward, which was based on relevance between retrieved results and query. Improved latent semantic kernel (LSK) was combined with analysis of variance (ANOVA) kernel to calculate the relevance. Experimental results showed that the result merging precision of the combination of LSK and ANOVA kernel (CLA) is 16.79%, 30.73%,20.37%, 24.17%, 14.25%, 13.50% and 7.53% higher than that of Round-robin, ComMNZ, Bayesian, Borda, SDM, MEM and regression SVM respectively. CLA kernel method has better performance for result merging and is a practical method for result merging in DIR.%为了提高分布式信息检索(DIR)的结果融合表现,基于改进的潜在语义核(LSK)和复合方差(ANOVA)核构建了新的复合(CLA)核,通过直接计算检索结果和提问之间相关度来对检索结果进行融合研究.实验结果表明:CLA核的融合精度和招回率分别仅略次于LSK和ANOVA核,但其综合评价指标F1优于其他核;其融合精度比Round-robin、ComMNZ、Bayesian、Borda、SDM、MEM和regression SVM等分别提高了16.79%、30.73%、20.37%、24.17%、14.25%、13.50%和7.53%.CLA核具有较好的融合表现,适用于DIR结果融合.

  14. 基于局部颜色-空间特征的图像检索方法研究%RESEARCH ON LOCAL COLOR-SPACE CHARACTERISTICS IMAGE RETRIEVAL METHOD

    Institute of Scientific and Technical Information of China (English)

    王保平; 赵静; 苏建康; 孙超; 郭俊杰

    2012-01-01

    The feature extraction methods for the uniform block color histogram and the accumulative color histogram are studied. Their merits and drawbacks that are considered about color statistical distribution and color spatial distribution are analyzed. Image retrieval is realized for the uniform block color histogram and the accumulative color histogram feature extraction methods, upon which improvements are made about feature extraction methods. An algorithm based on HSV non-uniform quantization block color histogram is proposed and validated. Research results indicate that the algorithm heals the lack of spatial information within color characteristics; moreover it is validated that compared to the uniform block color histogram and the accumulative color histogram, the algorithm based on HSV non-uniform block color histogram boasts for higher retrieval accuracy.%研究均匀分块颜色直方图和累加颜色直方图的特征提取方式,分析其在考虑颜色统计分布和颜色空间分布问题上的优点和缺点,实现均匀分块颜色直方图和累加颜色直方图特征提取方式的图像检索,并在此基础上对特征提取方式进行改进,提出一种基于HSV非均匀量化分块颜色直方图的算法,并对该算法进行验证.研究结果表明,该算法改善了颜色特征缺乏空间信息的缺点,并验证了基于HSV非均匀量化分块颜色直方图的算法相对于均匀分块颜色直方图和累加颜色直方图有较好的检索精度.

  15. Towards Better Retrievals in Content -Based Image Retrieval System

    Directory of Open Access Journals (Sweden)

    Kumar Vaibhava

    2014-04-01

    Full Text Available -This paper presents a Content-Based Image Retrieval (CBIR System called DEICBIR-2. The system retrieves images similar to a given query image by searching in the provided image database.Standard MPEG-7 image descriptors are used to find the relevant images which are similar to thegiven query image. Direct use of the MPEG-7 descriptors for creating the image database and retrieval on the basis of nearest neighbor does not yield accurate retrievals. To further improve the retrieval results, B-splines are used for ensuring smooth and continuous edges of the images in the edge-based descriptors. Relevance feedback is also implemented with user intervention. These additional features improve the retrieval performance of DEICBIR-2 significantly. Computational performance on a set of query images is presented and the performance of the proposed system is much superior to the performance of DEICBIR[9] on the same database and on the same set of query images.

  16. Changing Information Retrieval Behaviours

    DEFF Research Database (Denmark)

    Constantiou, Ioanna D.; Lehrer, Christiane; Hess, Thomas

    2014-01-01

    The introduction of smartphones and the accompanying profusion of mobile data services have had a profound effect on individuals' lives. One of the most influential service categories is location-based services (LBS). Based on insights from behavioural decision-making, a conceptual framework is d...... on the continuance of LBS use and indicate changes in individuals' information retrieval behaviours in everyday life. In particular, the distinct value dimension of LBS in specific contexts of use changes individuals' behaviours towards accessing location-related information....

  17. Compressive Shift Retrieval

    Science.gov (United States)

    Ohlsson, Henrik; Eldar, Yonina C.; Yang, Allen Y.; Sastry, S. Shankar

    2014-08-01

    The classical shift retrieval problem considers two signals in vector form that are related by a shift. The problem is of great importance in many applications and is typically solved by maximizing the cross-correlation between the two signals. Inspired by compressive sensing, in this paper, we seek to estimate the shift directly from compressed signals. We show that under certain conditions, the shift can be recovered using fewer samples and less computation compared to the classical setup. Of particular interest is shift estimation from Fourier coefficients. We show that under rather mild conditions only one Fourier coefficient suffices to recover the true shift.

  18. Information, conservation and retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Eng, T. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Norberg, E. [National Swedish Archives, Stockholm (Sweden); Torbacke, J. [Stockholm Univ. (Sweden). Dept. of History; Jensen, M. [Swedish Radiation Protection Inst., Stockholm (Sweden)

    1996-12-01

    The seminar took place on the Swedish ship for transportation of radioactive wastes, M/S Sigyn, which at summer time is used for exhibitions. The seminar treated items related to general information needs in society and questions related to radioactive waste, i.e. how knowledge about a waste repository should be passed on to future generations. Three contributions are contained in the report from the seminar and are indexed separately: `Active preservation - otherwise no achieves`; `The conservation and dissemination of information - A democratic issue`; and, `Conservation and retrieval of information - Elements of a strategy to inform future societies about nuclear waste repositories`.

  19. Music retrieval in ICOR

    Science.gov (United States)

    Finsterle, Lutz; Fischer, Stephan; Rimac, Ivica; Steinmetz, Ralf

    1999-08-01

    In this paper we describe music retrieval in ICOR, a project of Darmstadt TU. It is the goal of ICOR to find new interfaces to support applications of music video and music CDs. Although the project consists of audio and video analysis we concentrate on a description of the audio algorithms in this paper. We describe our MPEG-7 like data structure to store meta information for music pieces and explain which algorithms we use to analyze the content of music pieces automatically. We currently use an applause detection to distinguish live music from studio recordings, a genre classifier to distinguish pieces with beats form classical music, and a singer recognition.

  20. Multimedia Information Retrieval

    CERN Document Server

    Rueger, Stefan

    2009-01-01

    At its very core multimedia information retrieval means the process of searching for and finding multimedia documents; the corresponding research field is concerned with building the best possible multimedia search engines. The intriguing bit here is that the query itself can be a multimedia excerpt: For example, when you walk around in an unknown place and stumble across an interesting landmark, would it not be great if you could just take a picture with your mobile phone and send it to a service that finds a similar picture in a database and tells you more about the building -- and about its

  1. Difficult OptEase Filter Retrievals After Prolonged Indwelling Times

    Energy Technology Data Exchange (ETDEWEB)

    Van Ha, Thuong G., E-mail: tgvanha@radiology.bsd.uchicago.edu; Kang, Lisa; Lorenz, Jonathan; Zangan, Steven; Navuluri, Rakesh; Straus, Christopher; Funaki, Brian [University of Chicago, Section of Interventional Radiology, Department of Radiology (United States)

    2013-08-01

    PurposeThe OptEase vena cave filter (Cordis, Piscataway, NJ) is commercially available as a retrievable or permanent filter with short recommended indwelling time, presumably due to extensive contact of the filter side struts with the inferior vena cava wall and subsequent neointimal hyperplasia leading to incorporation. Our purpose was to evaluate OptEase filter retrievals with a long indwelling time period that required unconventional retrieval techniques.Materials and MethodsWe retrospectively reviewed patients who underwent OptEase filter retrieval with long undwelling times requiring additional maneuvers for retrieval. Techniques used included rigid endobronchial forceps dissection and wire-through-loop snare. Each patient underwent postretrieval venogram to evaluate for possible complications. In addition, patients had clinical follow-up 2 weeks after the retrieval procedure.ResultsThere were three patients (2 women, 1 man; average age 64 years) who underwent OptEase filter retrieval. The mean indwelling time was 6.4 months. The indwelling filters were successfully retrieved. There were no complications. Postprocedural follow-up showed no clinical pathology.ConclusionUnconventional techniques aided in the retrieval of OptEase filters with long indwelling times.

  2. Multiple image encryption by phase retrieval

    Science.gov (United States)

    Di, Hong; Kang, Yanmei; Liu, Yueqin; Zhang, Xin

    2016-07-01

    Multiple image encryption (MIE) was proposed to increase the efficiency of encrypting images by processing several images simultaneously. Because of the advantage of optical technology in processing twodimensional images at high throughput, MIE has been significantly improved by use of methods originating from optics. Phase retrieval was the process of algorithmically finding solutions to the phase loss problem due to light detectors only capturing the intensity. It was to retrieve phase information for the determination of a structure from diffraction data. Error-reduction algorithm is a typical phase retrieval method. Here, we employ it to illustrate that methods in phase retrieval are able to encrypt multiple images and compress them into encrypted data simultaneously. Moreover, the decryption is also designed to handle multiple images at the same time. The whole process including both the encryption and decryption is proposed to improve MIE with respect to the compression and efficiency. The feasibility and encryption of the MIE scheme is demonstrated with encryption experiments under Gaussian white noise and unauthorized access.

  3. Appraisal of {sup 15}N enrichment and {sup 15}N natural abundance methods for estimating N{sub 2} fixation by understorey Acacia leiocalyx and A. disparimma in a native forest of subtropical Australia

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Shahla Hosseini; Xu, Zhihong; Blumfield, Timothy J. [Griffith Univ., Nathan, Brisbane, QLD (Australia). School of Biomolecular and Physical Sciences, Environmental Futures Centre; Sun, Fangfang [Guangdong Academy of Agricultural Sciences, Guangzhou (China). Research Centre for Quality, Safety and Standard of Agricultural Products; Chen, Chengrong [Griffith Univ., Nathan, Brisbane, QLD (Australia). School of Environment, Environmental Futures Centre; Wild, Clyde [Griffith Univ., Gold Coast, QLD (Australia). School of Environment, Environmental Futures Centre

    2012-05-15

    Purpose: It is anticipated that global climate change will increase the frequency of wildfires in native forests of eastern Australia. Understorey legumes such as Acacia species play an important role in maintaining ecosystem nitrogen (N) balance through biological N fixation (BNF). This is particularly important in Australian native forests with soils of low nutrient status and frequent disturbance of the nutrient cycles by fires. This study aimed to examine {sup 15}N enrichment and {sup 15}N natural abundance techniques in terms of their utilisation for evaluation of N{sub 2} fixation of understorey acacias and determine the relationship between species ecophysiological traits and N{sub 2} fixation. Materials and methods: A trial was established at sites 1 and 2 located at Toohey Forest, Queensland, Australia, a eucalypt-dominated native forest, to examine the determination of BNF using {sup 15}N enrichment and {sup 15}N natural abundance methods. Toohey Forest is an urban forest and subjected to frequent fuel reduction burns to protect the adjacent properties. Plant physiological status was measured to determine the relationship between physiological and N{sub 2} fixation activities. Results and discussion: Both {sup 15}N enrichment and {sup 15}N natural abundance techniques may be used to estimate N{sub 2} fixation of acacia tree species. The estimation of BNF using {sup 15}N enrichment was higher than those of the {sup 15}N natural abundance method. A grass reference plant, Themeda triandra, as well as tree reference plants provided an appropriate {delta}{sup 15}N signal. Potential B values for Acacia spp. between -0.3 permille and 1.0 permille provided an acceptable BNF estimation. This suburban forest is located nearby a busy highway leading to N deposition over time with consequent negative {delta}{sup 15}N signal. This N deposition may explain the separation between the {delta}{sup 15}N signal of the acacias and that of the reference plants which led to

  4. Domain-Oriented Subject Aware Model for Multimedia Data Retrieval

    Directory of Open Access Journals (Sweden)

    Lingling Zi

    2013-01-01

    Full Text Available With the increment of the scale of internet information as well as the cross-correlation interaction, how to achieve accurate retrieval of multimedia data is an urgent question in terms of efficiently utilizing information resources. However, existing information retrieval approaches provide only limited capabilities to search multimedia data. In order to improve the ability of information retrieval, we propose a domain-oriented subject aware model by introducing three innovative improvements. Firstly, we propose the text-image feature mapping method based on the transfer learning to extract image semantics. Then we put forward the annotation document method to accomplish simultaneous retrieval of multimedia data. Lastly, we present subject aware graph to quantify the semantics of query requirements, which can customize query threshold to retrieve multimedia data. Conducted experiments show that our model obtained encouraging performance results.

  5. Automatic medical image annotation and keyword-based image retrieval using relevance feedback.

    Science.gov (United States)

    Ko, Byoung Chul; Lee, JiHyeon; Nam, Jae-Yeal

    2012-08-01

    This paper presents novel multiple keywords annotation for medical images, keyword-based medical image retrieval, and relevance feedback method for image retrieval for enhancing image retrieval performance. For semantic keyword annotation, this study proposes a novel medical image classification method combining local wavelet-based center symmetric-local binary patterns with random forests. For keyword-based image retrieval, our retrieval system use the confidence score that is assigned to each annotated keyword by combining probabilities of random forests with predefined body relation graph. To overcome the limitation of keyword-based image retrieval, we combine our image retrieval system with relevance feedback mechanism based on visual feature and pattern classifier. Compared with other annotation and relevance feedback algorithms, the proposed method shows both improved annotation performance and accurate retrieval results.

  6. Memory engram storage and retrieval.

    Science.gov (United States)

    Tonegawa, Susumu; Pignatelli, Michele; Roy, Dheeraj S; Ryan, Tomás J

    2015-12-01

    A great deal of experimental investment is directed towards questions regarding the mechanisms of memory storage. Such studies have traditionally been restricted to investigation of the anatomical structures, physiological processes, and molecular pathways necessary for the capacity of memory storage, and have avoided the question of how individual memories are stored in the brain. Memory engram technology allows the labeling and subsequent manipulation of components of specific memory engrams in particular brain regions, and it has been established that cell ensembles labeled by this method are both sufficient and necessary for memory recall. Recent research has employed this technology to probe fundamental questions of memory consolidation, differentiating between mechanisms of memory retrieval from the true neurobiology of memory storage.

  7. Personalized Mobile Information Retrieval System

    Directory of Open Access Journals (Sweden)

    Okkyung Choi

    2012-04-01

    Full Text Available Building a global Network Relations with the internet has made huge changes in personal information system and even comments left on a webpage of SNS(Social Network Services are appreciated as important elements that would provide valuable information for someone. Social Network is a relation between individuals or groups, represented in a graph model, which converts the concept of psychological and social relations into a logical structure by using node and link. But, most of the current personalized systems on the basis of Social Network are built and constructed mainly in the PC environment, and the systems are neither designed nor implemented in mobile environment. Hence, the objective of this study is to propose methods of providing Personalized Mobile Information Retrieval System using NFC (Near Field Communication Smartphone, which will be then used for Smartphone users. Besides, this study aims to verify its efficiency through a comparative analysis of existing studies.

  8. EM-21 Retrieval Knowledge Center: Waste Retrieval Challenges

    Energy Technology Data Exchange (ETDEWEB)

    Fellinger, Andrew P.; Rinker, Michael W.; Berglin, Eric J.; Minichan, Richard L.; Poirier, Micheal R.; Gauglitz, Phillip A.; Martin, Bruce A.; Hatchell, Brian K.; Saldivar, Eloy; Mullen, O Dennis; Chapman, Noel F.; Wells, Beric E.; Gibbons, Peter W.

    2009-04-10

    EM-21 is the Waste Processing Division of the Office of Engineering and Technology, within the U.S. Department of Energy’s (DOE) Office of Environmental Management (EM). In August of 2008, EM-21 began an initiative to develop a Retrieval Knowledge Center (RKC) to provide the DOE, high level waste retrieval operators, and technology developers with centralized and focused location to share knowledge and expertise that will be used to address retrieval challenges across the DOE complex. The RKC is also designed to facilitate information sharing across the DOE Waste Site Complex through workshops, and a searchable database of waste retrieval technology information. The database may be used to research effective technology approaches for specific retrieval tasks and to take advantage of the lessons learned from previous operations. It is also expected to be effective for remaining current with state-of-the-art of retrieval technologies and ongoing development within the DOE Complex. To encourage collaboration of DOE sites with waste retrieval issues, the RKC team is co-led by the Savannah River National Laboratory (SRNL) and the Pacific Northwest National Laboratory (PNNL). Two RKC workshops were held in the Fall of 2008. The purpose of these workshops was to define top level waste retrieval functional areas, exchange lessons learned, and develop a path forward to support a strategic business plan focused on technology needs for retrieval. The primary participants involved in these workshops included retrieval personnel and laboratory staff that are associated with Hanford and Savannah River Sites since the majority of remaining DOE waste tanks are located at these sites. This report summarizes and documents the results of the initial RKC workshops. Technology challenges identified from these workshops and presented here are expected to be a key component to defining future RKC-directed tasks designed to facilitate tank waste retrieval solutions.

  9. The potential of clear-sky carbon dioxide satellite retrievals

    Directory of Open Access Journals (Sweden)

    R. R. Nelson

    2015-12-01

    -mean-square (RMS errors of less than 2.0 ppm when adequately filtered through the use of the Data Ordering through Genetic Optimization (DOGO system. These results imply that non-scattering XCO2 retrievals are potentially much more accurate than previous literature suggests, when employing filtering methods to remove measurements in which scattering can cause significant errors. Additionally, the computational benefits of non-scattering retrievals means they may be useful for certain applications that require large amounts of data but have less stringent error requirements.

  10. Bibliometric-enhanced Information Retrieval

    CERN Document Server

    Mayr, Philipp; Larsen, Birger; Schaer, Philipp; Mutschke, Peter

    2013-01-01

    Bibliometric techniques are not yet widely used to enhance retrieval processes in digital libraries, although they offer value-added effects for users. In this workshop we will explore how statistical modelling of scholarship, such as Bradfordizing or network analysis of coauthorship network, can improve re-trieval services for specific communities, as well as for large, cross-domain col-lections. This workshop aims to raise awareness of the missing link between in-formation retrieval (IR) and bibliometrics/scientometrics and to create a common ground for the incorporation of bibliometric-enhanced services into retrieval at the digital library interface.

  11. Advanced Topics in Information Retrieval

    CERN Document Server

    Melucci, Massimo

    2011-01-01

    Information retrieval is the science concerned with the effective and efficient retrieval of documents starting from their semantic content. It is employed to fulfill some information need from a large number of digital documents. Given the ever-growing amount of documents available and the heterogeneous data structures used for storage, information retrieval has recently faced and tackled novel applications. In this book, Melucci and Baeza-Yates present a wide-spectrum illustration of recent research results in advanced areas related to information retrieval. Readers will find chapters on e.g

  12. Care episode retrieval: distributional semantic models for information retrieval in the clinical domain.

    Science.gov (United States)

    Moen, Hans; Ginter, Filip; Marsi, Erwin; Peltonen, Laura-Maria; Salakoski, Tapio; Salanterä, Sanna

    2015-01-01

    Patients' health related information is stored in electronic health records (EHRs) by health service providers. These records include sequential documentation of care episodes in the form of clinical notes. EHRs are used throughout the health care sector by professionals, administrators and patients, primarily for clinical purposes, but also for secondary purposes such as decision support and research. The vast amounts of information in EHR systems complicate information management and increase the risk of information overload. Therefore, clinicians and researchers need new tools to manage the information stored in the EHRs. A common use case is, given a--possibly unfinished--care episode, to retrieve the most similar care episodes among the records. This paper presents several methods for information retrieval, focusing on care episode retrieval, based on textual similarity, where similarity is measured through domain-specific modelling of the distributional semantics of words. Models include variants of random indexing and the semantic neural network model word2vec. Two novel methods are introduced that utilize the ICD-10 codes attached to care episodes to better induce domain-specificity in the semantic model. We report on experimental evaluation of care episode retrieval that circumvents the lack of human judgements regarding episode relevance. Results suggest that several of the methods proposed outperform a state-of-the art search engine (Lucene) on the retrieval task.

  13. Flare Plasma Iron Abundance

    Science.gov (United States)

    Dennis, Brian R.; Dan, Chau; Jain, Rajmal; Schwartz, Richard A.; Tolbert, Anne K.

    2008-01-01

    The equivalent width of the iron-line complex at 6.7 keV seen in flare X-ray spectra suggests that the iron abundance of the hottest plasma at temperatures >approx.10 MK may sometimes be significantly lower than the nominal coronal abundance of four times the photospheric value that is commonly assumed. This conclusion is based on X-ray spectral observations of several flares seen in common with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Solar X-ray Spectrometer (SOXS) on the second Indian geostationary satellite, GSAT-2. The implications of this will be discussed as it relates to the origin of the hot flare plasma - either plasma already in the corona that is directly heated during the flare energy release process or chromospheric plasma that is heated by flare-accelerated particles and driven up into the corona. Other possible explanations of lower-than-expected equivalent widths of the iron-line complex will also be discussed.

  14. A method for the retrieval of atomic oxygen density and temperature profiles from ground-based measurements of the O(+)(2D-2P) 7320 A twilight airglow

    Science.gov (United States)

    Fennelly, J. A.; Torr, D. G.; Richards, P. G.; Torr, M. R.; Sharp, W. E.

    1991-01-01

    This paper describes a technique for extracting thermospheric profiles of the atomic-oxygen density and temperature, using ground-based measurements of the O(+)(2D-2P) doublet at 7320 and 7330 A in the twilight airglow. In this method, a local photochemical model is used to calculate the 7320-A intensity; the method also utilizes an iterative inversion procedure based on the Levenberg-Marquardt method described by Press et al. (1986). The results demonstrate that, if the measurements are only limited by errors due to Poisson noise, the altitude profiles of neutral temperature and atomic oxygen concentration can be determined accurately using currently available spectrometers.

  15. CICERO, RETRIEVING THE HONORABLE

    Directory of Open Access Journals (Sweden)

    William A. Frank

    2014-12-01

    Full Text Available From Marcus Tullius Cicero’s philosophical writings, the author first draws out a modest network of ideas that informs his understanding of what it means to be a good man (vir bonus. Then, he finds in Cicero the idea of a befitting mutuality among four distinctively human capacities: a faculty for inquiry into and love for truth manifest in words and actions (reason; a disposition for the recognition of and attraction to things of worth beyond selfinterest (the honorable; an acute sense of one own spheres of responsibility along with facility for speaking and acting appropriately within them (appropriate action, and fostering and extending the bonds of mutual personal relations grounded in justice and benevolence (society. Against the background of deep commitments in modernity to hedonism and autonomous individualism, the author proposes a retrieval of the virtue of the honorable as an attractive alternative.

  16. Intelligent Information Retrieval

    CERN Document Server

    Kurtz, M J; Accomazzi, A; Grant, C; Henneken, E; Murray, S S; Kurtz, Michael J.; Eichhorn, Guenther; Accomazzi, Alberto; Grant, Carolyn; Henneken, Edwin; Murray, Stephen S.

    2005-01-01

    Since it was first announced at ADASS 2 the Smithsonian/NASA Astrophysics System Abstract Service (ADS) has played a central role in the information seeking behavior of astronomers. Central to the ability of the ADS to act as a search and discovery tool is its role as metadata agregator. Over the past 13 years the ADS has introduced many new techniques to facilitate information retrieval, broadly defined. We discuss some of these developments; with particular attention to how the ADS might inta754-1.pseract with the virtual observatory, and to the new myADS-arXiv customized open access virtual journal. The ADS is at http://ads.harvard.edu

  17. 甲醇沉淀法去除人血清高丰度蛋白质的实验研究%Establishment of methyl alcohol precipitation method for removing high abundant proteins in human serum

    Institute of Scientific and Technical Information of China (English)

    曹璐颖; 李克; 郑文杰

    2012-01-01

    Objective The common method of depleting the high abundant proteins in human serum is too complicated and ex -pensive to be applied to clinical practice . In this study, an effective and simple method of methyl alcohol precipitation was established for the removal of serum high abundant proteins. Methods The serum albumin of healthy controls was precipitated by different volume methyl alcohol. The removal effect was analyzed with one -dimensional sodium dodecyl sulfate -polyacrylamide gel electrophoresis ( SDS-PAGE) and quantitative method of albumin. Results Compared with the gel images of the original serum , the band of protein with molecular weight between 50000-80000 was removed. The results showed that the average concentration of albumin in the serum was de -creased from (47.65-.35) g/L to (1.16-.08) g/L. The removal ratio of protein was over 97% and the percentage of albumin in the total protein of serum was decreased from 65.4% to49.3%. The significantly statistical differences were observed (P<0.001). And the low abundance proteins could be seen and reserved . Conclusion The methyl alcohol depletion strategy may offer an effective and simple method to remove albumin from human serum , which provided a technical support for further study of serum proteomics .%目的 常用人血清高丰度蛋白质(high abundant proteins,HAP)去除方法操作较繁且成本高,文中探索建立简便有效的甲醇沉淀法去除人血清HAP.方法 用不同体积的甲醇处理血清样品,然后与原血清样品上样进行十二烷基磺酸钠聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)分析,并对去除HAP后的样品进行蛋白定量检测.结果 SDS-PAGE显示,经甲醇处理过的血清样品与原血清电泳结果 相比,相对分子质量在50000~80000 间的清蛋白等HAP被明显去除,血清清蛋白平均浓度显著降低,由(47.65±0.35)g /L下降至(1.16±0.08)g /L,去除率达97%以上,

  18. Multilevel resistive information storage and retrieval

    Science.gov (United States)

    Lohn, Andrew; Mickel, Patrick R.

    2016-08-09

    The present invention relates to resistive random-access memory (RRAM or ReRAM) systems, as well as methods of employing multiple state variables to form degenerate states in such memory systems. The methods herein allow for precise write and read steps to form multiple state variables, and these steps can be performed electrically. Such an approach allows for multilevel, high density memory systems with enhanced information storage capacity and simplified information retrieval.

  19. High-resolution NO2 observations from the Airborne Compact Atmospheric Mapper: Retrieval and validation

    Science.gov (United States)

    Lamsal, L. N.; Janz, S. J.; Krotkov, N. A.; Pickering, K. E.; Spurr, R. J. D.; Kowalewski, M. G.; Loughner, C. P.; Crawford, J. H.; Swartz, W. H.; Herman, J. R.

    2017-02-01

    Nitrogen dioxide (NO2) is a short-lived atmospheric pollutant that serves as an air quality indicator and is itself a health concern. The Airborne Compact Atmospheric Mapper (ACAM) was flown on board the NASA UC-12 aircraft during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality Maryland field campaign in July 2011. The instrument collected hyperspectral remote sensing measurements in the 304-910 nm range, allowing daytime observations of several tropospheric pollutants, including nitrogen dioxide (NO2), at an unprecedented spatial resolution of 1.5 × 1.1 km2. Retrievals of slant column abundance are based on the differential optical absorption spectroscopy method. For the air mass factor computations needed to convert these retrievals to vertical column abundance, we include high-resolution information for the surface reflectivity by using bidirectional reflectance distribution function data from the Moderate Resolution Imaging Spectroradiometer. We use high-resolution simulated vertical distributions of NO2 from the Community Multiscale Air Quality and Global Modeling Initiative models to account for the temporal variation in atmospheric NO2 to retrieve middle and lower tropospheric NO2 columns (NO2 below the aircraft). We compare NO2 derived from ACAM measurements with in situ observations from NASA's P-3B research aircraft, total column observations from the ground-based Pandora spectrometers, and tropospheric column observations from the space-based Ozone Monitoring Instrument. The high-resolution ACAM measurements not only give new insights into our understanding of atmospheric composition and chemistry through observation of subsampling variability in typical satellite and model resolutions, but they also provide opportunities for testing algorithm improvements for forthcoming geostationary air quality missions.

  20. Characterization of relative abundance of lactic acid bacteria species in French organic sourdough by cultural, qPCR and MiSeq high-throughput sequencing methods.

    Science.gov (United States)

    Michel, Elisa; Monfort, Clarisse; Deffrasnes, Marion; Guezenec, Stéphane; Lhomme, Emilie; Barret, Matthieu; Sicard, Delphine; Dousset, Xavier; Onno, Bernard

    2016-12-19

    In order to contribute to the description of sourdough LAB composition, MiSeq sequencing and qPCR methods were performed in association with cultural methods. A panel of 16 French organic bakers and farmer-bakers were selected for this work. The lactic acid bacteria (LAB) diversity of their organic sourdoughs was investigated quantitatively and qualitatively combining (i) Lactobacillus sanfranciscensis-specific qPCR, (ii) global sequencing with MiSeq Illumina technology and (iii) molecular isolates identification. In addition, LAB and yeast enumeration, pH, Total Titratable Acidity, organic acids and bread specific volume were analyzed. Microbial and physico-chemical data were statistically treated by Principal Component Analysis (PCA) and Hierarchical Ascendant Classification (HAC). Total yeast counts were 6 log10 to 7.6 log10CFU/g while LAB counts varied from 7.2 log10 to 9.6 log10CFU/g. Values obtained by L. sanfranciscensis-specific qPCR were estimated between 7.2 and 10.3 log10CFU/g, except for one sample at 4.4 log10CFU/g. HAC and PCA clustered the sixteen sourdoughs into three classes described by their variables but without links to bakers' practices. L. sanfranciscensis was the dominant species in 13 of the 16 sourdoughs analyzed by Next Generation Sequencing (NGS), by the culture dependent method this species was dominant only in only 10 samples. Based on isolates identification, LAB diversity was higher for 7 sourdoughs with the recovery of L. curvatus, L. brevis, L. heilongjiangensis, L. xiangfangensis, L. koreensis, L. pontis, Weissella sp. and Pediococcus pentosaceus, as the most representative species. L. koreensis, L. heilongjiangensis and L. xiangfangensis were identified in traditional Asian food and here for the first time as dominant in organic sourdough. This study highlighted that L. sanfranciscensis was not the major species in 6/16 sourdough samples and that a relatively high LAB diversity can be observed in French organic sourdough.

  1. Text Retrieval on a Microcomputer.

    Science.gov (United States)

    Giordano, Richard; And Others

    1988-01-01

    Presents description of the Generalized Automatic Text Organization and Retrieval system (GATOR), a database system that indexes and retrieves information from machine-readable texts such as interviews and case histories. Qualitative and quantitative analyses are discussed, and integrating GATOR with standard statistical packages is described.…

  2. Rhetorical relations for information retrieval

    DEFF Research Database (Denmark)

    Lioma, Christina; Larsen, Birger; Lu, Wei

    2012-01-01

    -called discourse structure has been applied successfully to several natural language processing tasks. This work studies the use of rhetorical relations for Information Retrieval (IR): Is there a correlation between certain rhetorical relations and retrieval performance? Can knowledge about a document’s rhetorical...

  3. Information retrieval in cultural heritage

    NARCIS (Netherlands)

    Koolen, M.; Kamps, J.; de Keijzer, V.

    2009-01-01

    This article discusses the opportunities and challenges of applying modern information retrieval techniques to the cultural heritage domain. Although the field of information retrieval is closely associated with computer science, it originally emerged from library science — also one of the main disc

  4. Intelligent Information Retrieval: An Introduction.

    Science.gov (United States)

    Gauch, Susan

    1992-01-01

    Discusses the application of artificial intelligence to online information retrieval systems and describes several systems: (1) CANSEARCH, from MEDLINE; (2) Intelligent Interface for Information Retrieval (I3R); (3) Gausch's Query Reformulation; (4) Environmental Pollution Expert (EP-X); (5) PLEXUS (gardening); and (6) SCISOR (corporate…

  5. Indexing Depth and Retrieval Effectiveness

    Science.gov (United States)

    Seely, Barbara J.

    1972-01-01

    There are six major studies of the effect of indexing depth on retrieval performance. They differ in purpose, methodology, measures, indexing language, field of study, and data base--nevertheless, all have found depth of indexing to have the same effect upon information retrieval. (13 references) (Author/NH)

  6. A Computerized Reference Retrieval System.

    Science.gov (United States)

    Harline, N. La Var

    An automated retrieval system for reference works was constructed as a prototype in order to illustrate the capabilities and potentialities of future retrieval systems. More than 170 biographical works were indexed and stored in a computer disk to form a biographical data base, and a computer program was written to match patron queries. Consistent…

  7. Passage Retrieval: A Probabilistic Technique.

    Science.gov (United States)

    Melucci, Massimo

    1998-01-01

    Presents a probabilistic technique to retrieve passages from texts having a large size or heterogeneous semantic content. Results of experiments comparing the probabilistic technique to one based on a text segmentation algorithm revealed that the passage size affects passage retrieval performance; text organization and query generality may have an…

  8. Metadata for Content-Based Image Retrieval

    Directory of Open Access Journals (Sweden)

    Adrian Sterca

    2010-12-01

    Full Text Available This paper presents an image retrieval technique that combines content based image retrieval with pre-computed metadata-based image retrieval. The resulting system will have the advantages of both approaches: the speed/efficiency of metadata-based image retrieval and the accuracy/power of content-based image retrieval.

  9. 基于AdaBoost的多特征融合指纹检索方法%Fingerprint Retrieval Method of Multi-feature Fusion Based on AdaBoost

    Institute of Scientific and Technical Information of China (English)

    王富丽; 欧阳建权

    2012-01-01

    为提高视频内容检索方法的鲁棒性,提出一种基于AdaBoost的多特征融合指纹检索方法.通过对样本数据的训练,自适应地获得尺度不变特征变换特征、运动特征以及音频特征的权重,利用得到的权重融合音视频特征,以产生视频指纹.实验结果表明,该方法的准确性较高,在尺度变化、亮度变化、音频噪音攻击下具有较好的鲁棒性.%This paper proposes a fingerprint retrieval method of multi-feature fusion based on AdaBoost to improve the robust of video fingerprint. The proposed method can gain the weight of Scale Invariant Feature Transform(SIFT), temporal and audio feature adaptively by training the sample data, then fuse audio-video feature to produce video fingerprint according to the weights of the three features. Experimental results show that this method can gain higher accuracy, and have good robustness under various geometric, brightness modification and audio noise.

  10. Iron abundance in the atmosphere of Arcturus

    CERN Document Server

    Sheminova, V A

    2015-01-01

    Abundance of iron in the atmosphere of Arcturus has been determined from the profiles or regions of the profiles of the weak lines sensitive to iron abundance. The selected lines of Fe I and Fe II were synthesized with the MARCS theoretical models of the atmosphere. From the observed profiles of lines available with a high spectral resolution in the atlas by Hinkle and Wallace (2005), the values of the iron abundance $A = 6.95 \\pm 0.03$ and the radial-tangential macroturbulent velocity $5.6 \\pm 0.2$ km/s were obtained for Arcturus. The same physical quantities were found for the Sun as a star; they are $7.42 \\pm 0.02$ and $3.4 \\pm 0.3$ km/s, respectively. For Arcturus, the iron abundance relative to the solar one was determined with the differential method as [Fe/H] $=-0.48 \\pm 0.02$.

  11. Atmospheric Retrieval for Direct Imaging Spectroscopy of Gas Giants in Reflected Light. II. Orbital Phase and Planetary Radius

    Science.gov (United States)

    Nayak, Michael; Lupu, Roxana; Marley, Mark S.; Fortney, Jonathan J.; Robinson, Tyler; Lewis, Nikole

    2017-03-01

    Future space-based telescopes, such as the Wide-Field Infrared Survey Telescope (WFIRST), will observe the reflected light spectra of directly imaged extrasolar planets. Interpretation of such data presents a number of novel challenges, including accounting for unknown planet radius and uncertain stellar illumination phase angle. Here, we report on our continued development of Markov Chain Monte Carlo retrieval methods for addressing these issues in the interpretation of such data. Specifically, we explore how the unknown planet radius and potentially poorly known observer-planet-star phase angle impacts retrievals of parameters of interest such as atmospheric methane abundance, cloud properties, and surface gravity. As expected, the uncertainty in retrieved values is a strong function of the signal-to-noise ratio (S/N) of the observed spectra, particularly for low metallicity atmospheres, which lack deep absorption signatures. Meaningful results may only be possible above certain S/N thresholds; for cases across a metallicity range of 1–50 times solar, we find that only an S/N of 20 systematically reproduces a value close to the correct methane abundance at all phase angles. However, even in cases where the phase angle is poorly known we find that the planet radius can be constrained to within a factor of two. We find that uncertainty in planet radius decreases at phase angles past quadrature, as the highly forward-scattering nature of the atmosphere at these geometries limits the possible volume of phase space that relevant parameters can occupy. Finally, we present an estimation of possible improvement that can result from combining retrievals against observations at multiple phase angles.

  12. An improved glyoxal retrieval from OMI measurements

    Directory of Open Access Journals (Sweden)

    L. M. A. Alvarado

    2014-06-01

    Full Text Available Satellite observations from the SCIAMACHY, GOME-2, and OMI spectrometers have been used to retrieve atmospheric columns of glyoxal (CHOCHO with the DOAS method. High CHOCHO levels are found over regions with large biogenic and pyrogenic emissions, and hot-spots have been identified over areas of anthropogenic activities. This study focuses on the development of an improved retrieval for CHOCHO from measurements by the OMI instrument. From sensitivity tests, an optimal fitting window and polynomial degree are determined. Two different approaches to reduce the interference of liquid water absorption over oceanic regions are evaluated, achieving significant reduction of negative columns over clear water regions. Moreover, a high temperature absorption cross-section of nitrogen dioxide (NO2 is introduced in the DOAS retrieval to account for potential interferences of NO2 over regions with large anthropogenic emissions, leading to improved fit quality over these areas. A comparison with vertical CHOCHO columns retrieved from measurements of the GOME-2 and SCIAMACHY instruments over continental regions is performed, showing overall good consistency. Using the new OMI CHOCHO data set, the link between fires and glyoxal columns is investigated for two selected regions in Africa. In addition, mapped averages are computed for a fire event in the east of Moscow between mid-July and mid-August 2010. In both cases, enhanced CHOCHO levels are found in close spatial and temporal proximity to MODIS fire radiative power, demonstrating that pyrogenic emissions can be clearly identified in the OMI CHOCHO product.

  13. Vector space model for document representation in information retrieval

    Directory of Open Access Journals (Sweden)

    Dan MUNTEANU

    2007-12-01

    Full Text Available This paper presents the basics of information retrieval: the vector space model for document representation with Boolean and term weighted models, ranking methods based on the cosine factor and evaluation measures: recall, precision and combined measure.

  14. International workshop on phase retrieval and coherent scattering. Coherence 2005

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, K.A.; Fienup, J.R.; Van Dyck, D.; Van Aert, S.; Weitkamp, T.; Diaz, A.; Pfeiffer, F.; Cloetens, P.; Stampanoni, M.; Bunk, O.; David, C.; Bronnikov, A.V.; Shen, Q.; Xiao, X.; Gureyev, T.E.; Nesterets, Ya.I.; Paganin, D.M.; Wilkins, S.W.; Mokso, R.; Cloetens, P.; Ludwig, W.; Hignette, O.; Maire, E.; Faulkner, H.M.L.; Rodenburg, J.M.; Wu, X.; Liu, H.; Grubel, G.; Ludwig, K.F.; Livet, F.; Bley, F.; Simon, J.P.; Caudron, R.; Le Bolloc' h, D.; Moussaid, A.; Gutt, C.; Sprung, M.; Madsen, A.; Tolan, M.; Sinha, S.K.; Scheffold, F.; Schurtenberger, P.; Robert, A.; Madsen, A.; Falus, P.; Borthwick, M.A.; Mochrie, S.G.J.; Livet, F.; Sutton, M.D.; Ehrburger-Dolle, F.; Bley, F.; Geissler, E.; Sikharulidze, I.; Jeu, W.H. de; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Lurio, L.B.; Hu, X.; Jiao, X.; Jiang, Z.; Naryanan, S.; Sinha, S.K.; Lal, J.; Naryanan, S.; Sinha, S.K.; Lal, J.; Robinson, I.K.; Chapman, H.N.; Barty, A.; Beetz, T.; Cui, C.; Hajdu, J.; Hau-Riege, S.P.; He, H.; Stadler, L.M.; Sepiol, B.; Harder, R.; Robinson, I.K.; Zontone, F.; Vogl, G.; Howells, M.; London, R.; Marchesini, S.; Shapiro, D.; Spence, J.C.H.; Weierstall, U.; Eisebitt, S.; Shapiro, D.; Lima, E.; Elser, V.; Howells, M.R.; Huang, X.; Jacobsen, C.; Kirz, J.; Miao, H.; Neiman, A.; Sayre, D.; Thibault, P.; Vartanyants, I.A.; Robinson, I.K.; Onken, J.D.; Pfeifer, M.A.; Williams, G.J.; Pfeiffer, F.; Metzger, H.; Zhong, Z.; Bauer, G.; Nishino, Y.; Miao, J.; Kohmura, Y.; Yamamoto, M.; Takahashi, Y.; Koike, K.; Ebisuzaki, T.; Ishikawa, T.; Spence, J.C.H.; Doak, B

    2005-07-01

    The contributions of the participants have been organized into 3 topics: 1) phase retrieval methods, 2) X-ray photon correlation spectroscopy, and 3) coherent diffraction imaging. This document gathers the abstracts of the presentations and of the posters.

  15. CONTENT BASED BATIK IMAGE RETRIEVAL

    Directory of Open Access Journals (Sweden)

    A. Haris Rangkuti

    2014-01-01

    Full Text Available Content Based Batik Image Retrieval (CBBIR is an area of research that focuses on image processing based on characteristic motifs of batik. Basically the image has a unique batik motif compared with other images. Its uniqueness lies in the characteristics possessed texture and shape, which has a unique and distinct characteristics compared with other image characteristics. To study this batik image must start from a preprocessing stage, in which all its color images must be removed with a grayscale process. Proceed with the feature extraction process taking motifs characteristic of every kind of batik using the method of edge detection. After getting the characteristic motifs seen visually, it will be calculated by using 4 texture characteristic function is the mean, energy, entropy and stadard deviation. Characteristic function will be added as needed. The results of the calculation of characteristic functions will be made more specific using the method of wavelet transform Daubechies type 2 and invariant moment. The result will be the index value of every type of batik. Because each motif there are the same but have different sizes, so any kind of motive would be divided into three sizes: Small, medium and large. The perfomance of Batik Image similarity using this method about 90-92%.

  16. Subhalo abundance matching and assembly bias in the EAGLE simulation

    Science.gov (United States)

    Chaves-Montero, Jonás; Angulo, Raul E.; Schaye, Joop; Schaller, Matthieu; Crain, Robert A.; Furlong, Michelle; Theuns, Tom

    2016-08-01

    Subhalo abundance matching (SHAM) is a widely used method to connect galaxies with dark matter structures in numerical simulations. SHAM predictions agree remarkably well with observations, yet they still lack strong theoretical support. We examine the performance, implementation, and assumptions of SHAM using the `Evolution and Assembly of Galaxies and their Environment' (EAGLE) project simulations. We find that Vrelax, the highest value of the circular velocity attained by a subhalo while it satisfies a relaxation criterion, is the subhalo property that correlates most strongly with galaxy stellar mass (Mstar). Using this parameter in SHAM, we retrieve the real-space clustering of EAGLE to within our statistical uncertainties on scales greater than 2 Mpc for galaxies with 8.77 EAGLE. The agreement is even better in redshift space, where the clustering is recovered to within our statistical uncertainties for all masses and separations. Additionally, we analyse the dependence of galaxy clustering on properties other than halo mass, i.e. the assembly bias. We demonstrate assembly bias alters the clustering in EAGLE by 20 per cent and Vrelax captures its effect to within 15 per cent. We trace small differences in the clustering to the failure of SHAM as typically implemented, i.e. the Mstar assigned to a subhalo does not depend on (i) its host halo mass, (ii) whether it is a central or a satellite. In EAGLE, we find that these assumptions are not completely satisfied.

  17. Subhalo abundance matching and assembly bias in the EAGLE simulation

    CERN Document Server

    Chaves-Montero, Jonás; Schaye, Joop; Schaller, Matthieu; Crain, Robert A; Furlong, Michelle

    2015-01-01

    Subhalo abundance matching (SHAM) is a widely-used method to connect galaxies with dark matter structures in numerical simulations. SHAM predictions agree remarkably well with observations, yet they still lack strong theoretical support. Here we examine the performance, search for the best implementation, and analyse the key assumptions of SHAM using cosmological simulations from the EAGLE project. We find that $V_{\\rm relax}$, the highest value of the circular velocity attained by a subhalo while it satisfies a relaxation criterion, is the subhalo property that correlates most strongly with galaxy stellar mass ($M_{\\rm star}$). Using this parameter in SHAM, we retrieve the real-space clustering of EAGLE to within our statistical uncertainties on scales greater than $2$ Mpc for galaxies with $8.77<\\log_{10}(M_{\\rm star}[M_\\odot])<10.77$. On the other hand, clustering is overestimated by $30\\%$ on scales below $2$ Mpc because SHAM slightly overpredicts the fraction of satellites in massive haloes. The ag...

  18. Image Retrieval via Relevance Vector Machine with Multiple Features

    Directory of Open Access Journals (Sweden)

    Zemin Liu

    2014-05-01

    Full Text Available With the fast development of computer network technique, there is large amount of image information every day. Researchers have paid more and more attention to the problem of how users quickly retrieving and identifying the images that they may interest. Meanwhile, with the rapid development of artificial intelligence and pattern recognition techniques, it provides people with new thought on the study on complex image retrieval while it’s very difficult for traditional machine learning method to get ideal retrieval results. For this reason, we in this paper propose a new approach for image retrieval based on multiple types of image features and relevance vector machine (RVM. The proposed method, termed as MF-RVM, integrates the informative cures of features and the discrimination ability of RVM. The retrieval experiment is conducted on COREL image library which is collected from internet. The experimental results show that the proposed method can significantly improve the performance for image retrieval, so MF-RVM presented in this paper has very high practicability in image retrieval.

  19. Primordial Deuterium Abundance Measurements

    CERN Document Server

    Levshakov, S A; Takahara, F; Levshakov, Sergei A.; Kegel, Wilhelm H.; Takahara, Fumio

    1997-01-01

    Deuterium abundances measured recently from QSO absorption-line systems lie in the range from 3 10^{-5} to 3 10^{-4}, which shed some questions on standard big bang theory. We show that this discordance may simply be an artifact caused by inadequate analysis ignoring spatial correlations in the velocity field in turbulent media. The generalized procedure (accounting for such correlations) is suggested to reconcile the D/H measurements. An example is presented based on two high-resolution observations of Q1009+2956 (low D/H) [1,2] and Q1718+4807 (high D/H) [8,9]. We show that both observations are compatible with D/H = 4.1 - 4.6 10^{-5}, and thus support SBBN. The estimated mean value = 4.4 10^{-5} corresponds to the baryon-to-photon ratio during SBBN eta = 4.4 10^{-10} which yields the present-day baryon density Omega_b h^2 = 0.015.

  20. INIS: manual for online retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Schiele, J.; Kurtev, I.; Ruckenbauer, E.; Stanik, Z.; Varecka, F.; Schmid, H.

    1984-03-01

    This manual is addressed to users participating in the INIS Online Service available at the IAEA in Vienna. The retrieval system used at the IAEA is IBM/STAIRS (Storage and Information Retrieval System), installed on an IBM mainframe computer operating under OS/MVS and the TP monitor CICS. STAIRS is a multipurpose software package which enables the user to carry out retrieval on suitably structured textual and/or numerical data files in both interactive (i.e. online) and batch modes. In addition to the actual retrieval modules, the system also includes a number of auxiliary facilities which assist in the preparation and management of search files, help the users in printing the document references retrieved and in saving formulated queries for later execution or SDI processing, etc. Because of certain modifications and extensions made by the IAEA, the retrieval dialogue will be slightly different from the standard STAIRS. The present manual describes the INIS/STAIRS database and the IAEA/STAIRS retrieval language.

  1. Retrieval of Atmospheric and Oceanic Parameters and the Relevant Numerical Calculation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    It is well known that retrieval of parameters is usually ill-posed and highly nonlinear, so parameter retrieval problems are very difficult. There are still many important theoretical issues under research,although great success has been achieved in data assimilation in meteorology and oceanography. This paper reviews the recent research on parameter retrieval, especially that of the authors. First, some concepts and issues of parameter retrieval are introduced and the state-of-the-art parameter retrieval technology in meteorology and oceanography is reviewed briefly, and then atmospheric and oceanic parameters are retrieved using the variational data assimilation method combined with the regularization techniques in four examples: retrieval of the vertical eddy diffusion coefficient; of the turbulivity of the atmospheric boundary layer; of wind from Doppler radar data, and of the physical process parameters. Model parameter retrieval with global and local observations is also introduced.

  2. 3D Model Retrieval Method of Mechanical Parts Based on Skeleton Tree%基于骨架树的机械零件三维模型检索方法

    Institute of Scientific and Technical Information of China (English)

    朱文博; 耿国庆; 刘阳阳; 张祥; 阳鼎

    2016-01-01

    A method for 3D model retrieval of mechanical parts based on skeleton tree is put forward. Retrieval is divided into two stages. The first stage is to extract the 3D model skeleton of mechanical parts, and then convert the skeleton into a skeleton tree. Using the adjacency matrix to describe the topological structure of the skeleton tree, the initial selection of mechanical parts is realized by comparing the sum of eigenvalues of the adjacent matrix. A large number of models which have a big difference with the matching model in topological structure are filtered out, which greatly reduces the matching computation of the second stage. The second stage, find the matched skeleton subtree firstly, search matched skeleton branches based on the matched subtree secondly, and then using the curvature and Frenet frame of space discrete curves to calculate the skeleton branches similarity, and then get the whole skeleton tree shape similarity. Through example analysis with the experiment, this method is effective and has high accuracy and good robustness.%提出了一种基于骨架树进行机械零件三维模型检索的方法。检索分为两个阶段。第一阶段首先提取机械零件三维模型骨架,然后将骨架转换成骨架树并用邻接矩阵来描述骨架树的拓扑结构特征,通过比较邻接矩阵特征值之和迅速完成零件拓扑结构匹配,实现零件的初步筛选。将大量与待匹配模型拓扑结构差异较大的模型过滤掉,极大地减少了第二阶段的匹配计算量。第二阶段首先寻找匹配的骨架子树,其次在匹配子树的基础上搜索骨架枝匹配对,进而采用空间离散曲线的曲率和弗朗内特标架进行空间曲线相似性计算,得到整个骨架形状相似度。通过实例验证与试验分析,该方法快速有效,具有较高的准确性和良好的鲁棒性。

  3. Regularization for Atmospheric Temperature Retrieval Problems

    Science.gov (United States)

    Velez-Reyes, Miguel; Galarza-Galarza, Ruben

    1997-01-01

    Passive remote sensing of the atmosphere is used to determine the atmospheric state. A radiometer measures microwave emissions from earth's atmosphere and surface. The radiance measured by the radiometer is proportional to the brightness temperature. This brightness temperature can be used to estimate atmospheric parameters such as temperature and water vapor content. These quantities are of primary importance for different applications in meteorology, oceanography, and geophysical sciences. Depending on the range in the electromagnetic spectrum being measured by the radiometer and the atmospheric quantities to be estimated, the retrieval or inverse problem of determining atmospheric parameters from brightness temperature might be linear or nonlinear. In most applications, the retrieval problem requires the inversion of a Fredholm integral equation of the first kind making this an ill-posed problem. The numerical solution of the retrieval problem requires the transformation of the continuous problem into a discrete problem. The ill-posedness of the continuous problem translates into ill-conditioning or ill-posedness of the discrete problem. Regularization methods are used to convert the ill-posed problem into a well-posed one. In this paper, we present some results of our work in applying different regularization techniques to atmospheric temperature retrievals using brightness temperatures measured with the SSM/T-1 sensor. Simulation results are presented which show the potential of these techniques to improve temperature retrievals. In particular, no statistical assumptions are needed and the algorithms were capable of correctly estimating the temperature profile corner at the tropopause independent of the initial guess.

  4. TEA: A Code Calculating Thermochemical Equilibrium Abundances

    Science.gov (United States)

    Blecic, Jasmina; Harrington, Joseph; Bowman, M. Oliver

    2016-07-01

    We present an open-source Thermochemical Equilibrium Abundances (TEA) code that calculates the abundances of gaseous molecular species. The code is based on the methodology of White et al. and Eriksson. It applies Gibbs free-energy minimization using an iterative, Lagrangian optimization scheme. Given elemental abundances, TEA calculates molecular abundances for a particular temperature and pressure or a list of temperature-pressure pairs. We tested the code against the method of Burrows & Sharp, the free thermochemical equilibrium code Chemical Equilibrium with Applications (CEA), and the example given by Burrows & Sharp. Using their thermodynamic data, TEA reproduces their final abundances, but with higher precision. We also applied the TEA abundance calculations to models of several hot-Jupiter exoplanets, producing expected results. TEA is written in Python in a modular format. There is a start guide, a user manual, and a code document in addition to this theory paper. TEA is available under a reproducible-research, open-source license via https://github.com/dzesmin/TEA.

  5. Robust methods for calculating indexes of abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Analysis of a spatially-explicit data set of recreational catch and effort data is underway to compare the “area-weighted sums” (AWS) approach to unweighted...

  6. Analysis of Ice Water Path Retrieval Errors Over Tropical Ocean

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Retrieval of multi-layered cloud properties, especially ice water path (IWP), is one of the most perplexing problems in satellite cloud remote sensing. This paper develops a method for improving the IWP retrievals for ice-over-water overlapped cloud systems using Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and Visible and Infrared Scanner (VIRS) data. A combined microwave, visible and infrared algorithm is used to identify overlapped clouds and estimate IWP separately from liquid water path. The retrieval error of IWP is then evaluated by comparing the IWP to that retrieved from single-layer ice clouds surrounding the observed overlapping systems. The major IWP retrieval errors of overlapped clouds are primarily controlled by the errors in estimating the visible optical depth. Optical depths are overestimated by about 10-40% due to the influence of the underlying cloud. For the ice-over-warm-water cloud systems (cloud water temperature Tw > 273 K), the globally averaged IWP retrieval error is about 10%. This cloud type accounts for about 15% of all high-cloud overlapping cases. Ice-over-super-cooled water clouds are the predominant overlapped cloud system, accounting for 55% of the cases. Their global averaged error is ~17.2%. The largest IWP retrieval error results when ice clouds occur over extremely super-cooled water clouds (Tw ≤ 255 K). Overall, roughly 33% of the VIRS IWP retrievals are overestimated due to the effects of the liquid water clouds beneath the cirrus clouds. To improve the accuracy of the IWP retrievals,correction models are developed and applied to all three types of overlapped clouds. The preliminary results indicate that the correction models reduce part of the retrieval error.

  7. Rhetorical relations for information retrieval

    DEFF Research Database (Denmark)

    Lioma, Christina; Larsen, Birger; Lu, Wei

    2012-01-01

    -called discourse structure has been applied successfully to several natural language processing tasks. This work studies the use of rhetorical relations for Information Retrieval (IR): Is there a correlation between certain rhetorical relations and retrieval performance? Can knowledge about a document’s rhetorical...... relations be useful to IR? We present a language model modification that considers rhetorical relations when estimating the relevance of a document to a query. Empirical evaluation of different versions of our model on TREC settings shows that certain rhetorical relations can benefit retrieval effectiveness...

  8. Mobile medical visual information retrieval.

    Science.gov (United States)

    Depeursinge, Adrien; Duc, Samuel; Eggel, Ivan; Müller, Henning

    2012-01-01

    In this paper, we propose mobile access to peer-reviewed medical information based on textual search and content-based visual image retrieval. Web-based interfaces designed for limited screen space were developed to query via web services a medical information retrieval engine optimizing the amount of data to be transferred in wireless form. Visual and textual retrieval engines with state-of-the-art performance were integrated. Results obtained show a good usability of the software. Future use in clinical environments has the potential of increasing quality of patient care through bedside access to the medical literature in context.

  9. Experiments With Height-dependent Parameterizations For Limb Profile Retrievals

    Science.gov (United States)

    Schwarz, G.; Hilgers, S.

    The implementation and validation of a level 2 processor for MIPAS - an atmospheric limb sounding instrument to be flown on the upcoming ENVISAT mission - led to a number of experiments with flexible data structures used for the retrieval of trace gas profiles. Besides the basic retrieval methods and the selected software concepts, these data structures represent one of the mainstays of the retrieval software; their flexibility has an immediate impact on the capabilities and the performance of the retrieval software. In particular, we compared the layout and implementation of data structures allowing the retrieval of trace gases and ancillary information with various methods on different height grids, the use of height dependent parameters and constraints, as well as the manipulation of the corresponding data during interpolations. Typical examples are nominal and actual measurement grids, user-oriented retrieval grids, libraries of atmospheric parameters, height dependent regularization param- eters, variances and co-variances, Jacobians (i.e. derivatives), a priori information, eigenvectors, and instrumental parameters. We will demonstrate typical examples outlining the additional retrieval performance offered by flexible data structures with respect to their implementation effort, and the risks involved during test and validation.

  10. Estimating the Retrievability of Temperature Profiles from Satellite Infrared Measurements

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A method is developed to assess retrievability, namely the retrieval potential for atmospheric temperature profiles, from satellite infrared measurements in clear-sky conditions. This technique is based upon generalized linear inverse theory and empirical orthogonal function analysis. Utilizing the NCEP global temperature reanalysis data in January and July from 1999 to 2003, the retrievabilities obtained with the Atmospheric Infrared Sounder (AIRS) and the High Resolution Infrared Radiation Sounder/3 (HIRS/3)sounding channel data are derived respectively for each standard pressure level on a global scale. As an incidental result of this study, the optimum truncation number in the method of generalized linear inverse is deduced too. The results show that the retrievabilities of temperature obtained with the two datasets are similar in spatial distribution and seasonal change characteristics. As for the vertical distribution, the retrievabilities are low in the upper and lower atmosphere, and high between 400 hPa and 850 hPa. For the geographical distribution, the retrievabilities are low in the low-latitude oceanic regions and in some regions in Antarctica, and relatively high in mid-high latitudes and continental regions. Compared with the HIRS/3 data, the retrievability obtained with the AIRS data can be improved by an amount between 0.15 and 0.40.

  11. A Novel Approach Towards Large Scale Cross-Media Retrieval

    Institute of Scientific and Technical Information of China (English)

    Bo Lu; Guo-Ren Wang; Ye Yuan

    2012-01-01

    With the rapid development of Internet and multimedia technology,cross-media retrieval is concerned to retrieve all the related media objects with multi-modality by submitting a query media object.Unfortunately,the complexity and the heterogeneity of multi-modality have posed the following two major challenges for cross-media retrieval:1) how to construct a unified and compact model for media objects with multi-modality,2) how to improve the performance of retrieval for large scale cross-media database.In this paper,we propose a novel method which is dedicate to solving these issues to achieve effective and accurate cross-media retrieval.Firstly,a multi-modality semantic relationship graph (MSRG) is constructed using the semantic correlation amongst the media objects with multi-modality.Secondly,all the media objects in MSRG are mapped onto an isomorphic semantic space.Further,an efficient indexing MK-tree based on heterogeneous data distribution is proposed to manage the media objects within the semantic space and improve the performance of cross-media retrieval.Extensive experiments on real large scale cross-media datasets indicate that our proposal dramatically improves the accuracy and efficiency of cross-media retrieval,outperforming the existing methods significantly.

  12. Montana StreamStats—A method for retrieving basin and streamflow characteristics in Montana: Chapter A in Montana StreamStats

    Science.gov (United States)

    McCarthy, Peter M.; Dutton, DeAnn M.; Sando, Steven K.; Sando, Roy

    2016-04-05

    The U.S. Geological Survey (USGS) provides streamflow characteristics and other related information needed by water-resource managers to protect people and property from floods, plan and manage water-resource activities, and protect water quality. Streamflow characteristics provided by the USGS, such as peak-flow and low-flow frequencies for streamflow-gaging stations, are frequently used by engineers, flood forecasters, land managers, biologists, and others to guide their everyday decisions. In addition to providing streamflow characteristics at streamflow-gaging stations, the USGS also develops regional regression equations and drainage area-adjustment methods for estimating streamflow characteristics at locations on ungaged streams. Regional regression equations can be complex and often require users to determine several basin characteristics, which are physical and climatic characteristics of the stream and its drainage basin. Obtaining these basin characteristics for streamflow-gaging stations and ungaged sites traditionally has been time consuming and subjective, and led to inconsistent results.StreamStats is a Web-based geographic information system application that was created by the USGS to provide users with access to an assortment of analytical tools that are useful for water-resource planning and management. StreamStats allows users to easily obtain streamflow and basin characteristics for USGS streamflow-gaging stations and user-selected locations on ungaged streams. The USGS, in cooperation with Montana Department of Transportation, Montana Department of Environmental Quality, and Montana Department of Natural Resources and Conservation, completed a study to develop a StreamStats application for Montana, compute streamflow characteristics at streamflow-gaging stations, and develop regional regression equations to estimate streamflow characteristics at ungaged sites. Chapter A of this Scientific Investigations Report describes the Montana Stream

  13. Retrieving the vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: A method based on a neural network with potential for global-scale applications

    Science.gov (United States)

    Sauzède, R.; Claustre, H.; Jamet, C.; Uitz, J.; Ras, J.; Mignot, A.; D'Ortenzio, F.

    2015-01-01

    neural network-based method is developed to assess the vertical distribution of (1) chlorophyll a concentration ([Chl]) and (2) phytoplankton community size indices (i.e., microphytoplankton, nanophytoplankton, and picophytoplankton) from in situ vertical profiles of chlorophyll fluorescence. This method (FLAVOR for Fluorescence to Algal communities Vertical distribution in the Oceanic Realm) uses as input only the shape of the fluorescence profile associated with its acquisition date and geo-location. The neural network is trained and validated using a large database including 896 concomitant in situ vertical profiles of High-Performance Liquid Chromatography (HPLC) pigments and fluorescence. These profiles were collected during 22 oceanographic cruises representative of the global ocean in terms of trophic and oceanographic conditions, making our method applicable to most oceanic waters. FLAVOR is validated with respect to the retrieval of both [Chl] and phytoplankton size indices using an independent in situ data set and appears to be relatively robust spatially and temporally. To illustrate the potential of the method, we applied it to in situ measurements of the BATS (Bermuda Atlantic Time Series Study) site and produce monthly climatologies of [Chl] and associated phytoplankton size indices. The resulting climatologies appear very promising compared to climatologies based on available in situ HPLC data. With the increasing availability of spatially and temporally well-resolved data sets of chlorophyll fluorescence, one possible global-scale application of FLAVOR could be to develop 3-D and even 4-D climatologies of [Chl] and associated composition of phytoplankton communities. The Matlab and R codes of the proposed algorithm are provided as supporting information.

  14. Probability to retrieve testicular spermatozoa in azoospermic patients

    Institute of Scientific and Technical Information of China (English)

    H.-J.Glander; L.-C.Horn; W.Dorschner; U.Paasch; J.Kratzsch

    2000-01-01

    Aim: The degree of probability to retrieve spermatozoa from testicular tissue for intracytoplasmic sperm injection into oocytes is of interest for counselling of infertility patients. We investigated the relation of sperm retrieval to clinical data and histological pattern in testicular biopsies from azoospermic patients. Methods: In 264 testicular biopsies from 142 azoospermic patients, the testicular tissue was shredded to separate the spermatozoa, histological semi - thin sections of which were then evaluated using Johnsen score. Results: The retrieval of spermatozoa correlated significantly ( P 18 U/L, testicular volume < 5 mL, mean Johnsen score<5, and maximum Johnsen score < 7.

  15. Scene change detection for video retrieval on MPEG streams

    Science.gov (United States)

    Kang, Eung-Kwan; Kim, Sung-Joo; Jahng, SurngGabb; Song, Ho-Keun; Choi, Jong S.

    2000-05-01

    IN this paper, we propose a new scene change detection (SCD) algorithm, and also provide a novel video-indexing scheme for fast content-based browsing and retrieval in video databases. We detect scene changes from the MPEG video sequence, and extract key frames to represent contents of a shot. Then, we perform the video indexing by applying the rosette pattern to the extracted key frames, and retrieve them. Our SCD method is better than the conventional ones in terms of the SCD performance. Moreover, by applying the rosette pattern for indexing, we can remarkably reduce the number of pixels required to index and excellently retrieve the video scene.

  16. A KEYWORD RETRIEVAL AND SORTING METHOD BASED ON ONTOLOGY FOR ENGINEERING DATA%基于本体的工程数据关键字检索和排序方法

    Institute of Scientific and Technical Information of China (English)

    张徵; 杨卫东; 李心玥; 施伯乐

    2014-01-01

    Engineering data exist widely in modern manufacturing industries.The keyword query method traditionally adopted in engineering data is hard to deal with heterogeneous documents and to identify the semantics of the keywords in engineering sector.Hence, we propose a new keyword retrieval framework for engineering data to tackle this deficiency.This framework extracts the text information from various heterogeneous engineering documents with proper tool first by building an ontology which represents the engineering data, and then sets up the“XML snapshots”.The XML snapshot tags the corresponding otology concepts to the indexed keywords.When a query comes, the framework first matches the keywords queried by the user to ontology concepts, and we present an algorithm to abate the semantic confusion of the keywords in matching process.On this basis, we then present a sorting model, which marks and sorts the XML snapshots tallied with the query, the marking emphatically considers the extent of the snapshot satisfying the keyword query in terms of semantics.The retrieval framework finally sorts and returns the original documents corresponded to the snapshots to user, makes the heterogeneous engineering data documents be able to processed and queried in uniform.This framework has high recall and precision ratios on retrieval results of engineering data, and has reasonable retrieval results sorting as well, it is suitable for massive engineering data documents in practical enterprises, and overcomes the defects of traditional engineering data retrieval.In experiment the actual datasets are used, it verifies and illustrates its effectiveness in practice and efficiency in performance.%工程数据大量存在于现代生产制造企业。传统工程数据上沿用的关键字查询方法具有难以处理各种异构文档、无法识别关键字在工程领域的语义等缺陷。针对此,提出一种新的工程数据关键字检索方法。该方法先通过建立

  17. Phase retrieval using nonlinear diversity.

    Science.gov (United States)

    Lu, Chien-Hung; Barsi, Christopher; Williams, Matthew O; Kutz, J Nathan; Fleischer, Jason W

    2013-04-01

    We extend the Gerchberg-Saxton algorithm to phase retrieval in a nonlinear system. Using a tunable photorefractive crystal, we experimentally demonstrate the noninterferometric technique by reconstructing an unknown phase object from optical intensity measurements taken at different nonlinear strengths.

  18. 非线性VAD反演低层风廓线拟合阶数优化方法%Optimization of Nonlinear VAD Method in the Low-level Wind Retrieval

    Institute of Scientific and Technical Information of China (English)

    马秀梅; 李文兆; 赵坤; 唐晓文; 杨洪平

    2014-01-01

    The performance of nonlinear velocity azimuth display method in the vertical wind profile retrieval at low levels (below 2 km)is quantitatively examined by combing the theoretical analysis and cases observed by SoWMEX S-Pol radar and Yangjiang radar in Guangdong Province.Results show that the general structure and evolution of the low-level wind profile can be reasonably deduced by traditional nonlinear VAD method.The root mean square error can be used to evaluate orders of velocity azimuth display (VAD)fitting,but small error does not always mean the better performance especially with big continuous data absence,and a specific example is given.When setting the VAD fitting order to 3 instead of 2 ,coeffi-cients which represent the horizontal wind u and v are closer to the wind derived from radial velocity im-age.However,when the fitting order comes to 4,coefficients lost their physical meaning.The wind direc-tion differs a lot and the speed is much smaller than the value before.At the same time,the root mean square error decreases compared with the order of 3 .Besides,data used in nonlinear VAD fitting come from the whole volume,which decreases quite a lot and leads to nonlinear VAD fitting error when the vol-ume coverage pattern (VCP)only has some lower elevations (e.g.,two elevations).Therefore,the re-trieved wind could contain large error in certain situations,such as for a region with large continuous data absence or a volume scan with fewer elevations. After carefully evaluating the impact of the corresponding parameters on the nonlinear VAD retrievals by analyzing radar measurements,a modified nonlinear VAD method is proposed which takes account of the maximum fitting order in horizontal (VAD)and vertical adaptively according to the size of continuous data absence and the number of sweeps in a volume scan.VAD fitting is abandoned when the data absence is larger than 90°;the order is set to 3 when the data absence is between 60°and 90°;and the order is set

  19. Document Retrieval on Repetitive Collections

    OpenAIRE

    Navarro, Gonzalo; Puglisi, Simon J.; Sirén, Jouni

    2014-01-01

    Document retrieval aims at finding the most important documents where a pattern appears in a collection of strings. Traditional pattern-matching techniques yield brute-force document retrieval solutions, which has motivated the research on tailored indexes that offer near-optimal performance. However, an experimental study establishing which alternatives are actually better than brute force, and which perform best depending on the collection characteristics, has not been carried out. In this ...

  20. Updated SAO OMI formaldehyde retrieval

    Directory of Open Access Journals (Sweden)

    G. González Abad

    2014-01-01

    Full Text Available We present and discuss the Smithsonian Astrophysical Observatory (SAO formaldehyde (H2CO retrieval algorithm for the Ozone Monitoring Instrument (OMI which is the operational retrieval for NASA OMI H2CO. The version of the algorithm described here includes relevant changes with respect to the operational one, including differences in the reference spectra for H2CO, the fit of O2-O2 collisional complex, updates in the high resolution solar reference spectrum, the use of a model reference sector over the remote Pacific Ocean to normalize the retrievals, an updated Air Mass Factor (AMF calculation scheme, and the inclusion of scattering weights and vertical H2CO profile in the level 2 products. The theoretical basis of the retrieval is discussed in detail. Typical values for retrieved vertical columns are between 4 × 1015 and 4 × 1016 molecules cm−2 with typical fitting uncertainties ranging between 40% and 100%. In high concentration regions the errors are usually reduced to 30%. The detection limit is estimated at 3 × 1015 molecules cm−2. These updated retrievals are compared with previous ones.

  1. The GRAPE aerosol retrieval algorithm

    Directory of Open Access Journals (Sweden)

    G. E. Thomas

    2009-11-01

    Full Text Available The aerosol component of the Oxford-Rutherford Aerosol and Cloud (ORAC combined cloud and aerosol retrieval scheme is described and the theoretical performance of the algorithm is analysed. ORAC is an optimal estimation retrieval scheme for deriving cloud and aerosol properties from measurements made by imaging satellite radiometers and, when applied to cloud free radiances, provides estimates of aerosol optical depth at a wavelength of 550 nm, aerosol effective radius and surface reflectance at 550 nm. The aerosol retrieval component of ORAC has several incarnations – this paper addresses the version which operates in conjunction with the cloud retrieval component of ORAC (described by Watts et al., 1998, as applied in producing the Global Retrieval of ATSR Cloud Parameters and Evaluation (GRAPE data-set.

    The algorithm is described in detail and its performance examined. This includes a discussion of errors resulting from the formulation of the forward model, sensitivity of the retrieval to the measurements and a priori constraints, and errors resulting from assumptions made about the atmospheric/surface state.

  2. Contextual Distance Refining for Image Retrieval

    KAUST Repository

    Islam, Almasri

    2014-09-16

    Recently, a number of methods have been proposed to improve image retrieval accuracy by capturing context information. These methods try to compensate for the fact that a visually less similar image might be more relevant because it depicts the same object. We propose a new quick method for refining any pairwise distance metric, it works by iteratively discovering the object in the image from the most similar images, and then refine the distance metric accordingly. Test show that our technique improves over the state of art in terms of accuracy over the MPEG7 dataset.

  3. Modeling Real Objects for Kansei-based Shape Retrieval

    Institute of Scientific and Technical Information of China (English)

    Yukihiro Koda; Ichi Kanaya; Kosuke Sato

    2007-01-01

    A large number of 3D models are created on computers and available for networks. Some content-based retrieval technologies are indispensable to find out particular data from such anonymous datasets. Though several shape retrieval technologies have been developed, little attention has been given to the points on human's sense and impression (as known as Kansei) in the conventional techniques. In this paper, the authors propose a novel method of shape retrieval based on shape impression of human's Kansei. The key to the method is the Gaussian curvature distribution from 3D models as features for shape retrieval. Then it classifies the 3D models by extracted feature and measures similarity among models in storage.

  4. Visual Ontology Construction for Digitized Art Image Retrieval

    Institute of Scientific and Technical Information of China (English)

    Shu-Qiang Jiang; Jun Du; Qing-Ming Huang; Tie-Jun Huang; Wen Gao

    2005-01-01

    Current investigations on visual information retrieval are generally content-based methods. The significant difference between similarity in Iow-level features and similarity in high-level semantic meanings is still a major challenge in the area of image retrieval. In this work, a scheme for constructing visual ontology to retrieve art images is proposed.The proposed ontology describes images in various aspects, including type & style, objects and global perceptual effects.Concepts in the ontology could be automatically derived. Various art image classification methods are employed based on low-level image features. Non-objective semantics are introduced, and how to express these semantics is given. The proposed ontology scheme could make users more naturally find visual information and thus narrows the "semantic gap".Experimental implementation demonstrates its good potential for retrieving art images in a human-centered manner.

  5. 云计算下大数据非结构的稳定性检索方法%Methods of unstructured big data stability retrieval in cloud computing

    Institute of Scientific and Technical Information of China (English)

    陈志华; 刘晓勇

    2016-01-01

    传统的云计算Hadoop 分布式多层体系架构数据检索模块难以满足云计算下大数据非结构的稳定性检索需求,因此采用需要结合存储非结构化大数据的特点,塑造新的集群的基础环境,通过云、端并重的形式,实现大数据非结构的稳定性检索。引入一种非结构大数据索引框架,作为非结构化数据库,当成数据检索引擎,改进云计算下大数据非结构的检索服务,给出检索技术在检索非结构化大数据过程中的关键代码。实验结果表明,所设计系统在检索云计算下非结构大数据的过程中,具有较高的查准率和较低的检索时间,可实现非结构云数据的稳定性检索。%It is difficult for the traditional cloud computing Hadoop distributed multi⁃layer architecture data retrieval module to meet the demand of the unstructured big⁃data stability retrieval in the cloud computing,so it is necessary to combine the characteristics of the unstructured large data storage,shape a new clustering basic environment,and pay equal attention to the form of cloud and end,to realize the stability retrieval of the unstructured big data. A big data index framework is taken as a un⁃structured database and as a data retrieval engine to improve the unstructured data retrieval service in cloud computing,and give the key code of the retrieval in the process of unstructured big data retrieval. Experiment result shows that the designed sys⁃tem,in the process of unstructured big data retrieval in the cloud computing,has high precision and short retrieval time,and can realize the stability retrieval of the structured cloud data.

  6. Data Fusion in Information Retrieval

    CERN Document Server

    Wu, Shengli

    2012-01-01

    The technique of data fusion has been used extensively in information retrieval due to the complexity and diversity of tasks involved such as web and social networks, legal, enterprise, and many others. This book presents both a theoretical and empirical approach to data fusion. Several typical data fusion algorithms are discussed, analyzed and evaluated. A reader will find answers to the following questions, among others: -          What are the key factors that affect the performance of data fusion algorithms significantly? -          What conditions are favorable to data fusion algorithms? -          CombSum and CombMNZ, which one is better? and why? -          What is the rationale of using the linear combination method? -          How can the best fusion option be found under any given circumstances?

  7. Wave impedance retrieving via Bloch modes analysis

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Ha, S.; Sukhorukov, A.;

    2011-01-01

    of the Bloch mode, respectively. Case studies prove that our ap-proach can determine material and wave effective parameters of lossy and lossless metamaterials. In some examples when the passivity is violated we made further analysis and showed that this is due to the failure of concept of impedance retrieving......-ciples violation, like antiresonance behaviour with Im(ε) mode analysis of periodic metamaterials to extract the dominating (fundamental) Bloch mode. Then it is possible to determine the Bloch and wave impedances by the surface and volume aver-aging of the electromagnetic field......The main bottleneck in the restoration of electromagnetic effective parameters is connected to the impedance retrieving. The S-parameters method gives the input (Bloch) impedance, which, being then used for permittivity and permeability determination, causes some fundamental physics prin...

  8. Phase retrieval techniques for adaptive optics

    Energy Technology Data Exchange (ETDEWEB)

    Carrano, C. J., LLNL

    1998-03-01

    We have developed and tested a method for minimizing static aberrations in adaptive optics systems. In order to correct the static phase aberrations, we need to measure the aberrations through the entire system. We have employed various phase retrieval algorithms to detect these aberrations. We have performed simulations of our experimental setup demonstrating that phase retrieval can improve the static aberrations to below the 20 nm rms level, with the limiting factor being local turbulence in the A0 system. Experimentally thus far, we have improved the static aberrations down to the 50 nm level, with the limiting factor being the ability to adjust the deformable mirror. This should be improved with better control algorithms now being implemented.

  9. COMPUTATIONALLY EFFICIENT PRIVATE INFORMATION RETRIEVAL PROTOCOL

    Directory of Open Access Journals (Sweden)

    A. V. Afanasyeva

    2016-03-01

    Full Text Available This paper describes a new computationally efficient private information retrieval protocol for one q-ary symbol retrieving. The main advantage of the proposed solution lies in a low computational complexity of information extraction procedure, as well as the constructive simplicity and flexibility in choosing the system parameters. Such results are based on cosets properties. The proposed protocol has communication complexity slightly worse than the best schemes at the moment, which is based on locally decodable codes, but it can be easily built for any parameters of the system, as opposed to codes. In comparison with similar solutions based on polynomials, the proposed method gains in computational complexity, which is important especially for servers which must service multiple requests from multiple users.

  10. A novel dependency language model for information retrieval

    Institute of Scientific and Technical Information of China (English)

    CAI Ke-ke; BU Jia-jun; CHEN Chun; QIU Guang

    2007-01-01

    This paper explores the application of term dependency in information retrieval (IR) and proposes a novel dependency retrieval model. This retrieval model suggests an extension to the existing language modeling (LM) approach to IR by introducing dependency models for both query and document. Relevance between document and query is then evaluated by reference to the Kullback-Leibler divergence between their dependency models. This paper introduces a novel hybrid dependency structure, which allows integration of various forms of dependency within a single framework. A pseudo relevance feedback based method is also introduced for constructing query dependency model. The basic idea is to use query-relevant top-ranking sentences extracted from the top documents at retrieval time as the augmented representation of query, from which the relationships between query terms are identified. A Markov Random Field (MRF) based approach is presented to ensure the relevance of the extracted sentences,which utilizes the association features between query terms within a sentence to evaluate the relevance of each sentence. This dependency retrieval model was compared with other traditional retrieval models. Experiments indicated that it produces significant improvements in retrieval effectiveness.

  11. Effective material parameter retrieval of anisotropic elastic metamaterials with inherent nonlocality

    Science.gov (United States)

    Lee, Hyung Jin; Lee, Heung Son; Ma, Pyung Sik; Kim, Yoon Young

    2016-09-01

    In this paper, the scattering (S-) parameter retrieval method is presented specifically for anisotropic elastic metamaterials; so far, no retrieval has been accomplished when elastic metamaterials exhibit fully anisotropic behavior. Complex constitutive property and intrinsic scattering behavior of elastic metamaterials make their characterization far more complicated than that for acoustic and electromagnetic metamaterials. In particular, elastic metamaterials generally exhibit anisotropic scattering behavior due to higher scattering modes associated with shear deformation. They also exhibit nonlocal responses to some degrees, which originate from strong multiple scattering interactions even in the long wavelength limit. Accordingly, the conventional S-parameter retrieval methods cannot be directly used for elastic metamaterials, because they determine only the diagonal components in effective tensor property. Also, the conventional methods simply use the analytic inversion formulae for the material characterization so that inherent nonlocality cannot be taken into account. To establish a retrieval method applicable to anisotropic elastic metamaterials, we propose an alternative S-parameter method to deal with full anisotropy of elastic metamaterials. To retrieve the whole effective anisotropic parameter, we utilize not only normal but also oblique wave incidences. For the retrieval, we first retrieve the ratio of the effective stiffness tensor to effective density and then determine the effective density. The proposed retrieval method is validated by characterizing the effective material parameters of various types of non-resonant anisotropic metamaterials. It is found that the whole effective parameters are retrieved consistently regardless of used retrieval conditions in spite of inherent nonlocality.

  12. Applying GA for Optimizing the User Query in Image and Video Retrieval

    Directory of Open Access Journals (Sweden)

    Ehsan Lotfi

    2014-12-01

    Full Text Available In an information retrieval system, the query can be made by user sketch. The new method presented here, optimizes the user sketch and applies the optimized query to retrieval the information. This optimization may be used in Content-Based Image Retrieval (CBIR and Content-Based Video Retrieval (CBVR which is based on trajectory extraction. To optimize the retrieval process, one stage of retrieval is performed by the user sketch. The retrieval criterion is based on the proposed distance metric from the user query. Retrieved answers are considered as the primary population for evolutionary optimization. The optimized query may be achieved through reproducing and minimizing the proposed measurement by using Genetic algorithm (GA. The optimized query could then be used for the retrieval of concepts from a given Data Base (DB. The proposed algorithms are evaluated for trajectory retrieval from urban traffic surveillance video and image retrieval from a DB. Practical implementations have demonstrated the high efficiency of this system in trajectory retrieval and image indexing.

  13. Graphical Retrieval Method for Orthorhombic Anisotropic Materials

    Science.gov (United States)

    2010-07-01

    Nat. Mater. 7, 31–37 (2008). 7. S. Zhang, W. Fan, N. C. Panoiu, K. J. Malloy , R. M. Osgood, and S. R. J. Brueck, “Experimental demonstration of near... Roberts , S. Feng, M. Moran, and L. Johnson, “Effective permittivity near zero in nanolaminates of silver and amorphous polycarbonate,” J. Nanophoton. 4

  14. An exponentiation method for XML element retrieval.

    Science.gov (United States)

    Wichaiwong, Tanakorn

    2014-01-01

    XML document is now widely used for modelling and storing structured documents. The structure is very rich and carries important information about contents and their relationships, for example, e-Commerce. XML data-centric collections require query terms allowing users to specify constraints on the document structure; mapping structure queries and assigning the weight are significant for the set of possibly relevant documents with respect to structural conditions. In this paper, we present an extension to the MEXIR search system that supports the combination of structural and content queries in the form of content-and-structure queries, which we call the Exponentiation function. It has been shown the structural information improve the effectiveness of the search system up to 52.60% over the baseline BM25 at MAP.

  15. HELIOS-Retrieval: An Open-source, Nested Sampling Atmospheric Retrieval Code, Application to the HR 8799 Exoplanets and Inferred Constraints for Planet Formation

    CERN Document Server

    Lavie, Baptiste; Mordasini, Christoph; Malik, Matej; Bonnefoy, Mickaël; Demory, Brice-Olivier; Oreshenko, Maria; Grimm, Simon L; Ehrenreich, David; Heng, Kevin

    2016-01-01

    We present an open-source retrieval code named HELIOS-Retrieval (hereafter HELIOS-R), designed to obtain chemical abundances and temperature-pressure profiles from inverting the measured spectra of exoplanetary atmospheres. In the current implementation, we use an exact solution of the radiative transfer equation, in the pure absorption limit, in our forward model, which allows us to analytically integrate over all of the outgoing rays (instead of performing Gaussian quadrature). Two chemistry models are considered: unconstrained chemistry (where the mixing ratios are treated as free parameters) and equilibrium chemistry (enforced via analytical formulae, where only the elemental abundances are free parameters). The nested sampling algorithm allows us to formally implement Occam's Razor based on a comparison of the Bayesian evidence between models. We perform a retrieval analysis on the measured spectra of the HR 8799b, c, d and e directly imaged exoplanets. Chemical equilibrium is disfavored by the Bayesian ...

  16. Color-image retrieval based on fuzzy correlation

    Institute of Scientific and Technical Information of China (English)

    ZHAI Hongchen; LIANG Yanmei; MU Guoguang

    2004-01-01

    We report a method of color-image retrieval based on fuzzy correlation, in which α-cut relations in fuzzy set theory are applied to defining color match and height match of color peaks for synthesizing fuzzy correlation of two color histograms, and RGB space is partitioned into six sub-regions in the experiment for the regional color comparisons. Experimental results show that the efficiency of the color-image retrieval can be effectively improved by this approach.

  17. EFFICIENT RETRIEVAL TECHNIQUES FOR IMAGES USING ENHANCED UNIVARIATE TRANSFORMATION APPROACH

    OpenAIRE

    DR.S.P.VICTOR,; MRS.V.NARAYANI,; S. Rajkumar

    2010-01-01

    Image mining is a process to find valid, useful, and understandable knowledge from large image sets or image databases. Image mining combines the areas of content-based image retrieval, image understanding, data mining and databases. Image mining deals with the extraction of knowledge, image data relationship, or other patterns not explicitly stored in the images. It uses methods from computer vision, image processing, image retrieval, data mining, machine learning, database, and artificial i...

  18. 引力搜索算法优化脉冲耦合网络的图像检索方法%Image Retrieval Method Using Pulse-Coupled Network Optimized by Gravitational Search Algorithm

    Institute of Scientific and Technical Information of China (English)

    雷虎; 樊泽明

    2016-01-01

    启发于脉冲耦合网络(PCN)在视觉特征表示方面的优势,提出使用引力搜索算法(GSA)优化脉冲耦合网络(PCN)来提取图像的视觉特征,对 PCN 的参数使用优化机制来提高所获取的特征质量,由此来提高基于内容的图像检索(CBIR)的分类和检索结果。首先对学习的图像用 PCN 生成特征码;然后计算特征码间的距离,距离变量作为适应度函数的输入;最后利用引力搜索算法优化 PCN 的几个变量,进行参数更新。在 Caltech256和 Corel 数据库上的实验结果表明提出方法的有效性,相比于改进的相关反馈方法(IRF)、颜色边缘结合离散小波变换方法(CE-DWT)和色矩结合局部二进制模式方法(CM-LBP),提出的方法检索精确度至少提高了5%,查全率提高4%左右。%Inspired by the visual features represented advantages in pulse coupling network (PCN),the method using gravitational search algorithm (GSA)to optimize pulse coupling network (PCN)to extract visual features is proposed,in which the parameters of PCN is applied to improve the quality of the acquired characteristics by optimization mechanism,thereby improving the classification and searching results of con-tent-based image retrieval (CBIR).Firstly,signature is generated by PCN using learning images.Then, the distance between the signature is calculated,and distance is being as the input of fitness function.Final-ly,gravitational search algorithm is used to optimize several variables of PCN,updating the parameters. The effectiveness of proposed method is verified by the experimental results on Caltech256 and Corel data-base,compared with method of improved relevance feedback (IRF),color edge combined discrete wavelet transform (CE-DWT)and color moments combined with local binary pattern (CM-LBP),the proposed method improves the retrieval accuracy by 5% at least,and the recall accuracy improves about 4%.

  19. Global distributions of methanol and formic acid retrieved for the first time from the IASI/MetOp thermal infrared sounder

    Directory of Open Access Journals (Sweden)

    A. Razavi

    2011-01-01

    Full Text Available Methanol (CH3OH and formic acid (HCOOH are among the most abundant volatile organic compounds present in the atmosphere. In this work, we derive the global distributions of these two organic species using for the first time the Infrared Atmospheric Sounding Interferometer (IASI launched onboard the MetOp-A satellite in 2006. This paper describes the method used and provides a first critical analysis of the retrieved products. The retrieval process follows a two-step approach in which global distributions are first obtained on the basis of a simple radiance indexing (transformed into brightness temperatures, and then mapped onto column abundances using suitable conversion factors. For methanol, the factors were calculated using a complete retrieval approach in selected regions. In the case of formic acid, a different approach, which uses a set of forward simulations for representative atmospheres, has been used. In both cases, the main error sources are carefully determined: the average relative error on the column for both species is estimated to be about 50%, increasing to about 100% for the least favorable conditions. The distributions for the year 2009 are discussed in terms of seasonality and source identification. Time series comparing methanol, formic acid and carbon monoxide in different regions are also presented.

  20. In Abundance: Networked Participatory Practices as Scholarship

    Science.gov (United States)

    Stewart, Bonnie E.

    2015-01-01

    In an era of knowledge abundance, scholars have the capacity to distribute and share ideas and artifacts via digital networks, yet networked scholarship often remains unrecognized within institutional spheres of influence. Using ethnographic methods including participant observation, interviews, and document analysis, this study investigates…

  1. Elaborative Retrieval: Do Semantic Mediators Improve Memory?

    Science.gov (United States)

    Lehman, Melissa; Karpicke, Jeffrey D.

    2016-01-01

    The elaborative retrieval account of retrieval-based learning proposes that retrieval enhances retention because the retrieval process produces the generation of semantic mediators that link cues to target information. We tested 2 assumptions that form the basis of this account: that semantic mediators are more likely to be generated during…

  2. A Novel Method of Key Frame Extraction for the Surveillance Video Content Retrieval%一种适合于监控视频内容检索的关键帧提取新方法

    Institute of Scientific and Technical Information of China (English)

    周兵; 郝伟伟; 袁社锋

    2013-01-01

    为减少监控视频的存储容量,便于用户迅速查看视频关键信息,提出一种适于监控视频内容检索的关键帧提取方法.首先,使用背景差分法检测含有运动物体的关键视频段,记录其起始帧和结束帧,然后,在关键视频段中基于联合直方图的方法进行关键帧的粗提取,最后,根据监控视频帧序列的连续性特征,通过图像的信息熵进一步精确提取关键帧,实验结果表明,该方法能有效地提取出监控视频中的关键帧,大大减少了视频数据的存储量,且便于用户浏览关键信息.%This paper proposes a new method of the key frame extraction aiming at reducing storage and fast retrieval of the surveillance video.First,an improved background subtraction is used to detect the key video segment which contains the moving objects,and record the first frame and the last frame of the segment.Then the key frames are extracted coarsely in the video segment based on the joint histogram.Finally,according to the continuity of the key video frames,we further refine the key frames by image information entropy.The experimental results show that the method can extract the key frames of the surveillance video effectively.It greatly reduces the storage of the video data,and helps the users to browse key information easily.

  3. Spectral Multimodal Hashing and Its Application to Multimedia Retrieval.

    Science.gov (United States)

    Zhen, Yi; Gao, Yue; Yeung, Dit-Yan; Zha, Hongyuan; Li, Xuelong

    2016-01-01

    In recent years, multimedia retrieval has sparked much research interest in the multimedia, pattern recognition, and data mining communities. Although some attempts have been made along this direction, performing fast multimodal search at very large scale still remains a major challenge in the area. While hashing-based methods have recently achieved promising successes in speeding-up large-scale similarity search, most existing methods are only designed for uni-modal data, making them unsuitable for multimodal multimedia retrieval. In this paper, we propose a new hashing-based method for fast multimodal multimedia retrieval. The method is based on spectral analysis of the correlation matrix of different modalities. We also develop an efficient algorithm that learns some parameters from the data distribution for obtaining the binary codes. We empirically compare our method with some state-of-the-art methods on two real-world multimedia data sets.

  4. Generalized eikonal approximation for fast retrieval of particle size distribution in spectral extinction technique.

    Science.gov (United States)

    Wang, Li; Sun, Xiaogang; Li, Feng

    2012-05-20

    In retrieving particle size distribution from spectral extinction data, a critical issue is the calculation of extinction efficiency, which affects the accuracy and rapidity of the whole retrieval. The generalized eikonal approximation (GEA) method, used as an alternative to the rigorous Mie theory, is introduced for retrieval of the unparameterized shape-independent particle size distribution (PSD). To compute the extinction efficiency more efficiently, the combination of GEA method and Mie theory is adopted in this paper, which not only extends the applicable range of the approximation method but also improves the speed of the whole retrieval. Within the framework of the combined approximation method, the accuracy and limitations of the retrieval are investigated. Moreover, the retrieval time and memory requirement are also discussed. Both simulations and experimental results show that the combined approximation method can be successfully applied to retrieval of PSD when the refractive index is within the validity range. The retrieval results we present demonstrate the high reliability and stability of the method. By using this method, we find the complexity and computation time of the retrieval are significantly reduced and the memory resources can also be saved effectively, thus making this method more suitable for online particle sizing.

  5. Diachronic Analysis on Users' Information Retrieval Mechanism%用户情报检索机制的历时性分析研究

    Institute of Scientific and Technical Information of China (English)

    韩毅

    2001-01-01

    The paper analyzes the information retrieval mechanism with diachrony method, divides information retrieval process into four circumstances, that is, information need, infomnation want, information demand and retrieval, and information assimilation and use, and based on Brooks Equation, goes further into details of information retrieval mechanism.

  6. Personalized Semantic Based Blog Retrieval

    Institute of Scientific and Technical Information of China (English)

    Godfrey Winster Sathianesan; Swamynathan Sankaranarayanan

    2012-01-01

    Blog retrieval is a complex task because of the informal language usage.Blogs deviate from the language which is used in traditional corpora largely due to various reasons.Spelling errors,grammatical irregularity,over use of abbreviations and symbolic characters like emotions are a few reasons of irregular corpus blogs.To make the retrieval of blogs easier,the novel idea of personalized semantic based blog retrieval (PSBBR) system is discussed in this paper.The blogs are tagged with a relationship to one another with reference to ontology.The meanings of the blog content and key term are tagged as XML tags.The query term accesses the XML tags to retrieve entire blog content.The system is evaluated with a huge number of blogs extracted from various blog sources.Relevance score is calculated for every blog associated with keywords and content-based importance (CBI) gives the content similarity to the query word.The experimental result shows the system performs well for the blog retrieval process.

  7. INFORMATION RETRIEVAL FOR SHORT DOCUMENTS

    Institute of Scientific and Technical Information of China (English)

    Qi Haoliang; Li Mu; Gao Jianfeng; Li Sheng

    2006-01-01

    The major problem of the most current approaches of information models lies in that individual words provide unreliable evidence about the content of the texts. When the document is short, e.g. only the abstract is available, the word-use variability problem will have substantial impact on the Information Retrieval (IR) performance. To solve the problem, a new technology to short document retrieval named Reference Document Model (RDM) is put forward in this letter. RDM gets the statistical semantic of the query/document by pseudo feedback both for the query and document from reference documents. The contributions of this model are three-fold: (1) Pseudo feedback both for the query and the document; (2) Building the query model and the document model from reference documents; (3) Flexible indexing units, which can be any linguistic elements such as documents, paragraphs, sentences, n-grams, term or character. For short document retrieval, RDM achieves significant improvements over the classical probabilistic models on the task of ad hoc retrieval on Text REtrieval Conference (TREC) test sets. Results also show that the shorter the document, the better the RDM performance.

  8. Radiative Transfer and Retrievals in EOF Domain

    Science.gov (United States)

    Liu, Xu; Zhou, Daniel K.; Larar, Allen; Smith, William L.; Schluessel, Peter

    2008-01-01

    The Infrared Atmospheric Sounding Interferometer (IASI) is a hyperspectral sensor with 8461 spectral channels and a nominal spectral resolution of 0.25 cm(sup -1). It is computationally intensive to perform radiative transfer calculations and inversions using all these channels. We will present a Principal Component-based Radiative Transfer Model (PCRTM) and a retrieval algorithm which perform all the necessary calculations in EOF domain. Since the EOFs are orthogonal to each other, only about 100 principal components are needed to represent the information content of the 8461 channels. The PCRTM provides the EOF coefficients and associated derivatives with respect to atmospheric and surface parameters needed by the inversion algorithm. The inversion algorithm is based on a non-linear Levenberg-Marquardt method with climatology covariance and a priori information as constraints. The retrieved parameters include atmospheric temperature, moisture and ozone profiles, cloud parameters, surface skin temperature, and surface emissivities. To make the retrieval system even more compact and stable. The atmospheric vertical profiles are compressed into the EOF space as well. The surface emissivities are also compressed into EOF space.

  9. The Application of ElasticSearch in the Massive Astronomical Data Retrieval

    Science.gov (United States)

    Chen, Y. J.; Wang, F.; Deng, H.; Liu, Y. B.

    2016-03-01

    Astronomical observational data are the fundamental element for modern astronomical researches. However, with the rapid increase of astronomical data, the traditional centralized retrieval methods are hard to meet the requirements of high- performance data retrieval. In the study, we present a novel method which is based on the ElasticSearch distributed retrieval engine and River mechanism to create data indexes, and provide high performance data retrieval for massive FITS (Flexible Image Transport System) data. We discuss the key technologies of the nearly real-time retrieval and query. The experimental results show that the method is capable of obtaining high retrieval performance especially for the cases in which the number of the FITS data exceeds millions or even tens of millions. Meanwhile, the method can be easily integrated into the current astronomical data archiving systems, and completely meet the archive requirements of all kinds of astronomical telescope systems.

  10. Support Vector Machine active learning for 3D model retrieval

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, we present a novel Support Vector Machine active learning algorithm for effective 3D model retrieval using the concept of relevance feedback. The proposed method learns from the most informative objects which are marked by the user, and then creates a boundary separating the relevant models from irrelevant ones. What it needs is only a small number of 3D models labelled by the user. It can grasp the user's semantic knowledge rapidly and accurately. Experimental results showed that the proposed algorithm significantly improves the retrieval effectiveness. Compared with four state-of-the-art query refinement schemes for 3D model retrieval, it provides superior retrieval performance after no more than two rounds of relevance feedback.

  11. Adaptive multi-agent system for information retrieval

    Science.gov (United States)

    Maleki-dizaji, Saeedeh; Nyongesa, H. O.; Siddiqqi, J.

    2001-10-01

    The current exponential growth of the Internet precipitates a need for improved tools to help people cope with the volume of information available. Existing search engines such, as Yahoo, Alta vista and Excite are efficient in terms of high recall (percentage of relevant document that are retrieved from Internet), and fast response time, at the cost of poor precision (percentage of documents retrieved that are considered relevant). The problem is due to the lack of filtering, lack of specialisation, lack of relevance feedback, lack of adaptation and lack of exploration. One solution for the above problems is to use intelligent agents, which can operate autonomously and become better over time. The agents rely on a user model to improve their performance in retrieving the information. This paper presents an adaptive information retrieval (IR) that learns from the user feedback through an evolutionary method, namely, genetic algorithms (GA).

  12. Pareto-depth for multiple-query image retrieval.

    Science.gov (United States)

    Hsiao, Ko-Jen; Calder, Jeff; Hero, Alfred O

    2015-02-01

    Most content-based image retrieval systems consider either one single query, or multiple queries that include the same object or represent the same semantic information. In this paper, we consider the content-based image retrieval problem for multiple query images corresponding to different image semantics. We propose a novel multiple-query information retrieval algorithm that combines the Pareto front method with efficient manifold ranking. We show that our proposed algorithm outperforms state of the art multiple-query retrieval algorithms on real-world image databases. We attribute this performance improvement to concavity properties of the Pareto fronts, and prove a theoretical result that characterizes the asymptotic concavity of the fronts.

  13. Efficient adaptive retrieval and mining in large multimedia databases

    DEFF Research Database (Denmark)

    Assent, Ira

    2009-01-01

    Multimedia data ranging from images to videos and time series is created in numerous scientific, commercial and home applications. Access to increasingly large data volumes stored in multimedia databases is a core task to retrieve similar objects or to generate an overview of the entire content...... using novel filter functions with quality guarantees ensure that fast response times are achieved without any loss of result accuracy. This thesis is structured as follows: first, in the Preliminaries, an overview over the thesis and the major challenges in multimedia retrieval and mining is given. Part....... Examples include retrieval of similar magnetic resonance images for diagnostic purposes, or automatic detection of customer segments for sales promotion. Meaningful retrieval and pattern detection require content-based methods that describe the relevant characteristics of multimedia objects. As opposed...

  14. A comprehensive collection of experimentally validated primers for Polymerase Chain Reaction quantitation of murine transcript abundance

    Directory of Open Access Journals (Sweden)

    Wang Xiaowei

    2008-12-01

    Full Text Available Abstract Background Quantitative polymerase chain reaction (QPCR is a widely applied analytical method for the accurate determination of transcript abundance. Primers for QPCR have been designed on a genomic scale but non-specific amplification of non-target genes has frequently been a problem. Although several online databases have been created for the storage and retrieval of experimentally validated primers, only a few thousand primer pairs are currently present in existing databases and the primers are not designed for use under a common PCR thermal profile. Results We previously reported the implementation of an algorithm to predict PCR primers for most known human and mouse genes. We now report the use of that resource to identify 17483 pairs of primers that have been experimentally verified to amplify unique sequences corresponding to distinct murine transcripts. The primer pairs have been validated by gel electrophoresis, DNA sequence analysis and thermal denaturation profile. In addition to the validation studies, we have determined the uniformity of amplification using the primers and the technical reproducibility of the QPCR reaction using the popular and inexpensive SYBR Green I detection method. Conclusion We have identified an experimentally validated collection of murine primer pairs for PCR and QPCR which can be used under a common PCR thermal profile, allowing the evaluation of transcript abundance of a large number of genes in parallel. This feature is increasingly attractive for confirming and/or making more precise data trends observed from experiments performed with DNA microarrays.

  15. An improved glyoxal retrieval from OMI measurements

    Science.gov (United States)

    Alvarado, L. M. A.; Richter, A.; Vrekoussis, M.; Wittrock, F.; Hilboll, A.; Schreier, S. F.; Burrows, J. P.

    2014-12-01

    Satellite observations from the SCIAMACHY, GOME-2 and OMI spectrometers have been used to retrieve atmospheric columns of glyoxal (CHOCHO) with the DOAS method. High CHOCHO levels were found over regions with large biogenic and pyrogenic emissions, and hot-spots have been identified over areas of anthropogenic activities. This study focuses on the development of an improved retrieval for CHOCHO from measurements by the OMI instrument. From sensitivity tests, a fitting window and a polynomial degree are determined. Two different approaches to reduce the interference of liquid water absorption over oceanic regions are evaluated, achieving significant reduction of the number of negative columns over clear water regions. The impact of using different absorption cross-sections for water vapour is evaluated and only small differences are found. Finally, a high-temperature (boundary layer ambient: 294 K) absorption cross-section of nitrogen dioxide (NO2) is introduced in the DOAS retrieval to account for potential interferences of NO2 over regions with large anthropogenic emissions, leading to improved fit quality over these areas. A comparison with vertical CHOCHO columns retrieved from GOME-2 and SCIAMACHY measurements over continental regions is performed, showing overall good consistency. However, SCIAMACHY CHOCHO columns are systematically higher than those obtained from the other instruments. Using the new OMI CHOCHO data set, the link between fires and glyoxal columns is investigated for two selected regions in Africa. In addition, mapped averages are computed for a fire event in Russia between mid-July and mid-August 2010. In both cases, enhanced CHOCHO levels are found in close spatial and temporal proximity to elevated levels of MODIS fire radiative power, demonstrating that pyrogenic emissions can be clearly identified in the new OMI CHOCHO product.

  16. Retrieval method of GOCI\\AOT using two stream approximate algorithm and its application%采用二流式算法的GOCI\AOT反演方法及其应用

    Institute of Scientific and Technical Information of China (English)

    姚玲玲; 张霄宇; 江彬彬

    2016-01-01

    针对静止海洋水色传感器(GOCI)2.1μm 短波红外通道缺失和高太阳天顶角的特点,采用二流式算法,并考虑气溶胶的折射率、地球曲率等因素,重新计算地表反射率、表观反射率以及反演 GOCI 气溶胶光学厚度(AOT ).结果表明:参数重新计算后的 GOCI\AOT 反演精度明显增高;根据目前广泛使用的实测 AOT (440 nm)>1.00霾判定阈值,采用线性内插方法,建议 GOCI\AOT 以 AOT (555 nm)>0.81作为霾判定阈值;中分辨率成像光谱仪(MODIS)是业务化的极轨卫星,GOCI\AOT 整体略大于 MODIS \AOT ,拟合精度 R2=0.82.以2015年11月27日至同年12月2日华北地区发生的霾事件为例,结合具有大范围观测能力的 MODIS 卫星,多源遥感监测方法有效地反映了该霾事件的动态发展过程.%Aerosol optical thickness (AOT ) of geostationary ocean color imager (GOCI ) was retrieved based on the two-stream approximate algorithm considering aerosol refractive index and earth curvature and other causations ,aiming at the lackage of 2 .1 μm short wave infrared band and the high solar zenith angle of GOCI . As specified , the retrieval precision of GOCI \\AOT gets improved after parameters recalculation .According to the widely used groundbase haze threshold of AOT (440 nm) > 1 .00 ,GOCI\\AOT (555 nm) > 0 .81 is proposed as the haze determination threshold based on the linear interpolation method . Moderate resolution imaging spectroradiometer (MODIS ) is an operational polar orbiting satellite ,GOCI \\AOT is slightly higher than MODIS \\AOT with R2 of 0 .82 . The haze event from November 27 to December 2 ,2015 was selected as one case and MODIS satellite was combined to realize real-time dynamic monitoring of haze events over North China ,which indicates that the multi satellites remote sensing monitoring method can reflect the dynamic process of haze event effectively .

  17. 基于倒排列表的网流索引检索与压缩方法%A Method of Net Flow Index Retrieval and Compression based on Inverted List

    Institute of Scientific and Technical Information of China (English)

    陈震; 刘洪健

    2014-01-01

    Nowadays, with the pervasive usage of computer and Internet, the amount of Internet traffic is increasing dramatically. Traffic monitor is essential in network security and traffic forensic analysis. To monitor the flow, we are able to record the flow information of traffic, such as source IP, destination IP, source Port, destination Port, Protocol field, and timestamp etc. With this information, one can collect the statistics of traffic and conduct further analysis of attack pattern etc. However, the amount of flow information increases very fast. Searching a specified IP address could be low efficiency if we do not index flow information completely. As we know, inverted index is the key method of a practical search engine. Thus, this paper applies the idea of inverted index and index compress algorithm to the net flow information retrieval. After the analysis and experiment, the result shows that inverted index method is feasible in flow information retrieval and can improve the query performance as expected.%随着计算机的广泛应用以及互联网的飞速发展,互联网流量呈现爆炸式增长的态势。为了应对日益严重的网络滥用以及网络安全事件,出于安全取证的需要,必须对互联网流量进行收集、存储和分析。互联网流量的监控需要及时统计网络流量的源地址、目的地址、源端口、目的端口、协议、时间戳等信息,以便进行流量统计和综合分析。但是网络流量信息是海量的,如何快速检索相关流量是一个挑战性问题。在搜索引擎中,为了处理海量数据检索,倒排索引是快速搜索技术的关键方法。文章把搜索引擎中的倒排索引方法和索引压缩算法应用到互联网网流信息检索中。通过实验测试和验证,在网流信息检索中,倒排索引以及索引压缩算法能够有效提高检索速度。

  18. Using radiance of cloud shadow for retrieve Investigation of AOD retrieval with Himawari-8 satellite data

    Science.gov (United States)

    Sun, Ta-Min; Chang, Yuan-Hsiang; Chang, Kuo-En; Lin, Tang-Huang

    2016-04-01

    As we know, the emission of pollutants, such as dust storm, biomass burning and anthropogenic pollution are serious issues related to the environmental change and human health topics in Asia. With the high temporal observation over a broad area, the new generated geostationary satellite, Himawari-8 (H-8) seems to be a good choice for atmospheric pollution monitor. It can provide the observation over Asia with 16 bands in visible and thermal infrared spectral every 10 minutes. For the atmospheric pollutant monitor by means of remote sensing, the retrieval of aerosol optical depth (AOD) is the most important index. In this study, the long method is employed for AOD retrieval which depends on the path radiance significantly. Apparent radiance of the suitable cloud shadow is selected as the path radiance. In order to let the atmospheric pollution monitor is used efficiently, so the distribution of the path radiance is using the objective analysis to expand it. The results of AOD retrieval from H-8 visible data are well consistent with MODIS (Moderate Resolution Imaging Spectroradiometer) AOD products and ground measurements AERONET (Aerosol Robotic Networks), indicating the practical of proposed approach for the AOD retrieval with H-8 data.

  19. Bayesian retrieval in associative memories with storage errors.

    Science.gov (United States)

    Sommer, F T; Dayan, P

    1998-01-01

    It is well known that for finite-sized networks, onestep retrieval in the autoassociative Willshaw net is a suboptimal way to extract the information stored in the synapses. Iterative retrieval strategies are much better, but have hitherto only had heuristic justification. We show how they emerge naturally from considerations of probabilistic inference under conditions of noisy and partial input and a corrupted weight matrix. We start from the conditional probability distribution over possible patterns for retrieval. This contains all possible information that is available to an observer of the network and the initial input. Since this distribution is over exponentially many patterns, we use it to develop two approximate, but tractable, iterative retrieval methods. One performs maximum likelihood inference to find the single most likely pattern, using the (negative log of the) conditional probability as a Lyapunov function for retrieval. In physics terms, if storage errors are present, then the modified iterative update equations contain an additional antiferromagnetic interaction term and site dependent threshold values. The second method makes a mean field assumption to optimize a tractable estimate of the full conditional probability distribution. This leads to iterative mean field equations which can be interpreted in terms of a network of neurons with sigmoidal responses but with the same interactions and thresholds as in the maximum likelihood update equations. In the absence of storage errors, both models become very similiar to the Willshaw model, where standard retrieval is iterated using a particular form of linear threshold strategy.

  20. Gaseous abundances in M82

    CERN Document Server

    Ranalli, P; Origlia, L; Maiolino, R; Makishima, K; Ranalli, Piero; Comastri, Andrea; Origlia, Livia; Maiolino, Roberto; Makishima, Kazuo

    2005-01-01

    We present the preliminary analysis of a deep (100ks) XMM-Newton observation of M82. The spatial distribution of the abundances of chemical elements (Fe, O, Ne, Mg, Si, S) is investigated through narrow-band imaging analisys and spatially-resolved spectroscopy. We find that the abundances of alpha-elements follow a bipolar distribution, these elements being more abundant in the gaseous outflow than in the galaxy centre. This behaviour is found to be more marked for lighter elements (O, Ne) than for heavier elements.