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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

    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...

  2. 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...

  3. Novel retrieval of volcanic SO 2 abundance from ultraviolet spectra

    Science.gov (United States)

    Salerno, G. G.; Burton, M. R.; Oppenheimer, C.; Caltabiano, T.; Tsanev, V. I.; Bruno, N.

    2009-03-01

    The recent development of fixed networks of scanning ultraviolet spectrometers for automatic determination of volcanic SO 2 fluxes has created tremendous opportunities for monitoring volcanoes but has brought new challenges in processing (and interpreting) the copious data flow they produce. A particular difficulty in standard implantation of differential optical absorption (DOAS) methods is the requirement for a clear-sky (plume-free) background spectrum. Our experience after four years of measurements with two UV scanner networks on Etna and Stromboli shows that wide plumes are frequently observed, precluding simple selection of clear-sky spectra. We have therefore developed a retrieval approach based on simulation of the background spectrum. We describe the method here and tune it empirically by collecting clear, zenith sky spectra using calibration cells containing known amounts of SO 2. We then test the performance of this optimised retrieval using clear-sky spectra collected with the same calibration cells but for variable scan angles, time of day, and season (through the course of 1 year), finding acceptable results (~ 12% error) for SO 2 column amounts. We further illustrate the analytical approach using spectra recorded at Mt. Etna during its July 2006 eruption. We demonstrate the reliability of the method for tracking volcano dynamics on different time scales, and suggest it is widely suited to automated SO 2-plume monitoring.

  4. Retrieving optical constants of glasses with variable iron abundance

    Science.gov (United States)

    Carli, C.; Roush, T. L.; Capaccioni, F.; Baraldi, A.

    2013-12-01

    Visible and Near Infrared (VNIR, ~0.4-2.5 μm) spectroscopy is an important tool to explore the surface composition of objects in our Solar System. Using this technique different minerals have been recognized on the surfaces of solar system bodies. One of the principal products of extrusive volcanism and impact cratering is a glassy component, that can be abundant and thus significantly influence the spectral signature of the region investigated. Different types of glasses have been proposed and identified on the lunar surface and in star forming regions near young stellar objects. Here we report an initial effort of retrieving the optical constants of volcanic glasses formed in oxidizing terrestrial-like conditions. We also investigated how those calculations are affected by the grain size distribution. Bidirectional reflectance spectra, obtained with incidence and emission angles of 30° and 0°, respectively, were measured on powders of different grain sizes for four different glassy compositions in the VNIR. Hapke's model of the interaction of light with particulate surfaces was used to determine the imaginary index, k, at each wavelength by iteratively minimizing the difference between measured and calculated reflectance The basic approach to retrieving the optical constants was to use multiple grain sizes of the same sample and assume all grain sizes are compositionally equivalent. Unless independently known as a function of wavelength, an additional assumption must be made regarding the real index of refraction, n. The median size for each particle size separate was adopted for initially estimating k. Then, iterating the Hapke analysis results with a subtractive Kramers-Kronig analysis we were able to determine the wavelength dependence of n. For each composition we used the k-values estimated for all the grain sizes to calculate a mean k-value representing that composition. These values were then used to fit the original spectra by only varying the grain

  5. 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.

  6. 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.

  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. 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.

  9. Novel retrieval of volcanic SO2 abundance from ultraviolet spectra

    OpenAIRE

    Salerno, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Burton, M. R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Oppenheimer, C.; University of Cambridge, Department of Geography; Caltabiano, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Tsanev, V. I.; University of Cambridge, Department of Chemistry, Department of Geography; Bruno, N.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Randazzo, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia

    2008-01-01

    The recent development of fixed networks of scanning ultraviolet spectrometers for automatic determination of volcanic SO2 fluxes has created tremendous opportunities for monitoring volcanoes but has brought new challenges in processing of the substantial data flow they produce. A particular difficulty in standard implantation of differential optical absorption (DOAS) methods is the requirement for a clear-sky (plume-free) background spectrum. Our experience after four years of measurements w...

  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. 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...... of artificial branches of the refractive index and simplicity in implementation. We prove the validity of the method on three case studies of homogeneous magnetized plasma, bi-cross and U-shaped metamaterials....

  12. 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 ind......, 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.......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...

  13. 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.

  14. 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.

  15. 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.

  16. A diagram retrieval method with multi-label learning

    Science.gov (United States)

    Fu, Songping; Lu, Xiaoqing; Liu, Lu; Qu, Jingwei; Tang, Zhi

    2015-01-01

    In recent years, the retrieval of plane geometry figures (PGFs) has attracted increasing attention in the fields of mathematics education and computer science. However, the high cost of matching complex PGF features leads to the low efficiency of most retrieval systems. This paper proposes an indirect classification method based on multi-label learning, which improves retrieval efficiency by reducing the scope of compare operation from the whole database to small candidate groups. Label correlations among PGFs are taken into account for the multi-label classification task. The primitive feature selection for multi-label learning and the feature description of visual geometric elements are conducted individually to match similar PGFs. The experiment results show the competitive performance of the proposed method compared with existing PGF retrieval methods in terms of both time consumption and retrieval quality.

  17. 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.

  18. Infrared Retrievals of Ice Cloud Properties and Uncertainties with an Optimal Estimation Retrieval Method

    Science.gov (United States)

    Wang, C.; Platnick, S. E.; Meyer, K.; Zhang, Z.

    2014-12-01

    We developed an optimal estimation (OE)-based method using infrared (IR) observations to retrieve ice cloud optical thickness (COT), cloud effective radius (CER), and cloud top height (CTH) simultaneously. The OE-based retrieval is coupled with a fast IR radiative transfer model (RTM) that simulates observations of different sensors, and corresponding Jacobians in cloudy atmospheres. Ice cloud optical properties are calculated using the MODIS Collection 6 (C6) ice crystal habit (severely roughened hexagonal column aggregates). The OE-based method can be applied to various IR space-borne and airborne sensors, such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and the enhanced MODIS Airborne Simulator (eMAS), by optimally selecting IR bands with high information content. Four major error sources (i.e., the measurement error, fast RTM error, model input error, and pre-assumed ice crystal habit error) are taken into account in our OE retrieval method. We show that measurement error and fast RTM error have little impact on cloud retrievals, whereas errors from the model input and pre-assumed ice crystal habit significantly increase retrieval uncertainties when the cloud is optically thin. Comparisons between the OE-retrieved ice cloud properties and other operational cloud products (e.g., the MODIS C6 and CALIOP cloud products) are shown.

  19. Using optimal estimation method for upper atmospheric Lidar temperature retrieval

    Science.gov (United States)

    Zou, Rongshi; Pan, Weilin; Qiao, Shuai

    2016-07-01

    Conventional ground based Rayleigh lidar temperature retrieval use integrate technique, which has limitations that necessitate abandoning temperatures retrieved at the greatest heights due to the assumption of a seeding value required to initialize the integration at the highest altitude. Here we suggests the use of a method that can incorporate information from various sources to improve the quality of the retrieval result. This approach inverts lidar equation via optimal estimation method(OEM) based on Bayesian theory together with Gaussian statistical model. It presents many advantages over the conventional ones: 1) the possibility of incorporating information from multiple heterogeneous sources; 2) provides diagnostic information about retrieval qualities; 3) ability of determining vertical resolution and maximum height to which the retrieval is mostly independent of the a priori profile. This paper compares one-hour temperature profiles retrieved using conventional and optimal estimation methods at Golmud, Qinghai province, China. Results show that OEM results show a better agreement with SABER profile compared with conventional one, in some region it is much lower than SABER profile, which is a very different results compared with previous studies, further studies are needed to explain this phenomenon. The success of applying OEM on temperature retrieval is a validation for using as retrieval framework in large synthetic observation systems including various active remote sensing instruments by incorporating all available measurement information into the model and analyze groups of measurements simultaneously to improve the results.

  20. 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.

  1. 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.

  2. 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.

  3. Robust method to retrieve the constitutive effective parameters of metamaterials.

    Science.gov (United States)

    Chen, Xudong; Grzegorczyk, Tomasz M; Wu, Bae-Ian; Pacheco, Joe; Kong, Jin Au

    2004-01-01

    We propose an improved method to retrieve the effective constitutive parameters (permittivity and permeability) of a slab of metamaterial from the measurement of S parameters. Improvements over existing methods include the determination of the first boundary and the thickness of the effective slab, the selection of the correct sign of effective impedance, and a mathematical method to choose the correct branch of the real part of the refractive index. The sensitivity of the effective constitutive parameters to the accuracy of the S parameters is also discussed. The method has been applied to various metamaterials and the successful retrieval results prove its effectiveness and robustness. PMID:15324190

  4. 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.

  5. 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

  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. 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...

  8. 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).

  9. 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).

  10. A Photometric Method for estimating CNO Abundances in Globular Clusters

    CERN Document Server

    Peat, David; Peat, David; Butler, Raymond

    2002-01-01

    Stromgren indices v and b are combined with broad-band index I, and a new index p, the short wavelength half of the v band, to estimate CN 4215A molecular absorption in a sample of stars in M22. The results have been used to estimate carbon and nitrogen abundances and suggest groups of stars within this cluster, each with a characteristic nitrogen abundance, but with a range of carbon abundances. The results suggest the possibility of stars consisting of material which has undergone CNO recycling two or three times. The method can be subsequently used for other globular clusters.

  11. Discrepancy between mRNA and protein abundance: Insight from information retrieval process in computers

    OpenAIRE

    Wang, Degeng

    2008-01-01

    Discrepancy between the abundance of cognate protein and RNA molecules is frequently observed. A theoretical understanding of this discrepancy remains elusive, and it is frequently described as surprises and/or technical difficulties in the literature. Protein and RNA represent different steps of the multi-stepped cellular genetic information flow process, in which they are dynamically produced and degraded. This paper explores a comparison with a similar process in computers - multi-step inf...

  12. [A spectral unmixing method of estimating main minerals abundance of lunar soils].

    Science.gov (United States)

    Yan, Bo-Kun; Li, Jian-Zhong; Gan, Fu-Ping; Yang, Su-Ming; Wang, Run-Sheng

    2012-12-01

    Estimating minerals abundance from reflectance spectra is one of the fundamental goals of remote sensing lunar exploration, and the main difficulties are the complicated mixing law of minerals spectrum and spectral features being sensitive to several kinds of factors such as topography, particle size and roughness etc. A method based on spectral unmixing was put forward and tested in the present paper. Before spectra are unmixed the spectral continuum is removed for clarifying and strengthening spectral features. The absorption features and reflectance features (the upward curving parts of spectra between absorption features) are integrated for unmixing to improve the unmixing performance. The Hapke model was used to correct unmixing error due to nonlinear mixing of minerals spectra. Forty three mixed spectra of olivine, clinopyroxene, hypersthene and plagioclase were used to validate the above method. The four minerals abundance was estimated under the conditions of being unaware of endmember spectra used to mix, granularity and chemical composition of minerals. Residual error, abundance error and correlation coefficient between retrieved and true abundance were 5.0 Vol%, 14.4 Vol% and 0.92 respectively. The method and result of this paper could be referred in the lunar minerals mapping of imaging spectrometer data such as M3. PMID:23427563

  13. A 2-Step Laemmli and Antigen Retrieval Method Improves Immunodetection.

    Science.gov (United States)

    Scalia, Carla R; Gendusa, Rossella; Cattoretti, Giorgio

    2016-07-01

    Detection by immunohistochemistry of antigens relies on reproducibly optimal preanalytical and analytical variables such as fixation conditions, antigen retrieval (AR), and the resolutive power of the detection system. There is a need to improve immunodetection on routinely fixed and embedded material, particularly for scarcely represented but relevant antigens. We devised a 2-step method and applied it to a panel of antigens of common use for diagnosis, prognosis, individualized therapy use, or research. The first step consists of a 10 minutes. Incubation at 95°C with a modified Laemmli extraction buffer. This was followed by a traditional AR method. Detection of the vast majority of antigens was improved over a simple AR with preservation of tissue integrity, as shown by quantitative image analysis. The mechanism underlying the improved detection may be controlled denaturation followed by heat-mediated retrieval, a method we dubbed "antigen relaxing" and which will improve routine detection of scarce antigens in formalin-fixed, paraffin-embedded material. PMID:26067142

  14. 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.

  15. 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.

  16. 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)

  17. Application of Tikhonov regularization method to wind retrieval from scatterometer data Ⅱ:cyclone wind retrieval with consideration of rain

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

    According to the conclusion of the simulation experiments in paper I, the Tikhonov regularization method is applied to cyclone wind retrieval with a rain-effect-considering geophysical model function (called GMF+Rain). The GMF+Rain model which is based on the NASA scatterometer-2 (NSCAT2) GMF is presented to compensate for the effects of rain on cyclone wind retrieval. With the multiple solution scheme (MSS), the noise of wind retrieval is effectively suppressed, but the influence of the background increases. It will cause a large wind direction error in ambiguity removal when the background error is large. However, this can be mitigated by the new ambiguity removal method of Tikhonov regularization as proved in the simulation experiments. A case study on an extratropical cyclone of hurricane observed with SeaWinds at 25-km resolution shows that the retrieved wind speed for areas with rain is in better agreement with that derived from the best track analysis for the GMF+Rain model, but the wind direction obtained with the two-dimensional variational (2DVAR) ambiguity removal is incorrect. The new method of Tikhonov regularization effectively improves the performance of wind direction ambiguity removal through choosing appropriate regularization parameters and the retrieved wind speed is almost the same as that obtained from the 2DVAR.

  18. Advanced Methods for Localized Content Based Image Retrieval

    OpenAIRE

    Radhey Shyam; Pooja Srivastava

    2012-01-01

    Localized Content based image retrieval is an effective technique for image retrieval in large databases. It is the retrieval of images based on visual features such as color, texture and shape. In this paper, our desired content of an image is not holistic, but is localized. Specifically, we define Localized Content-Based Image Retrieval, where the user is only interested in a portion of the image, and the rest of the image is irrelevant. Some work already has been done in this direction. We...

  19. 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.

  20. 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...

  1. Integrating methods from IR and QA for geographic information retrieval

    OpenAIRE

    LEVELING, JOHANNES; Hartrumpf, Sven

    2009-01-01

    This paper describes the participation of GIRSA at Geo- CLEF 2008, the geographic information retrieval task at CLEF. GIRSA combines information retrieval (IR) on geographically annotated data and question answering (QA) employing query decomposition. For the monolingual German experiments, several parameter settings were varied: using a single index or separate indexes for content and geographic annotation, using complex term weighting, adding location names from the topic narrative, a...

  2. 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。

  3. 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.

  4. Method for measuring the heavy stripped ion abundances of plasma

    International Nuclear Information System (INIS)

    A description is given of a system which uses a velocity filter and an energy filter in tandem to analyze the abundances and energy spreads of highly stripped ions. The system can also serve as a plasma diagnostic. (Auth.)

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

    Directory of Open Access Journals (Sweden)

    A.Kannan

    2010-11-01

    Full Text Available 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 color distributions [12].

  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. A joint method to retrieve directional ocean wave spectra from SAR and wave spectrometer data

    Science.gov (United States)

    Ren, Lin; Yang, Jingsong; Zheng, Gang; Wang, Juan

    2016-07-01

    This paper proposes a joint method to simultaneously retrieve wave spectra at different scales from spaceborne Synthetic Aperture Radar (SAR) and wave spectrometer data. The method combines the output from the two different sensors to overcome retrieval limitations that occur in some sea states. The wave spectrometer sensitivity coefficient is estimated using an effective significant wave height (SWH), which is an average of SAR-derived and wave spectrometer-derived SWH. This averaging extends the area of the sea surface sampled by the nadir beam of the wave spectrometer to improve the accuracy of the estimated sensitivity coefficient in inhomogeneous sea states. Wave spectra are then retrieved from SAR data using wave spectrometer-derived spectra as first guess spectra to complement the short waves lost in SAR data retrieval. In addition, the problem of 180° ambiguity in retrieved spectra is overcome using SAR imaginary cross spectra. Simulated data were used to validate the joint method. The simulations demonstrated that retrieved wave parameters, including SWH, peak wave length (PWL), and peak wave direction (PWD), agree well with reference parameters. Collocated data from ENVISAT advanced SAR (ASAR), the airborne wave spectrometer STORM, the PHAROS buoy, and the European Centre for Medium-Range Weather Forecasting (ECMWF) were then used to verify the proposed method. Wave parameters retrieved from STORM and two ASAR images were compared to buoy and ECMWF wave data. Most of the retrieved parameters were comparable to reference parameters. The results of this study show that the proposed joint retrieval method could be a valuable complement to traditional methods used to retrieve directional ocean wave spectra, particularly in inhomogeneous sea states.

  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. Improved retrieval of gas abundances from near-infrared solar FTIR spectra measured at the Karlsruhe TCCON station

    OpenAIRE

    Kiel, M.; Wunch, D.; Wennberg, P. O.; Toon, G. C.; Hase, F.; Blumenstock, T.

    2016-01-01

    We present a modified retrieval strategy for solar absorption spectra recorded by the Karlsruhe Fourier Transform Infrared (FTIR) spectrometer, which is operational within the Total Carbon Column Observing Network (TCCON). In typical TCCON stations, the 3800–11 000 cm−1 spectral region is measured on a single extended Indium Gallium Arsenide (InGaAs) detector. The Karlsruhe setup instead splits the spectrum across an Indium Antimonide (InSb) and InGaAs detecto...

  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.; Mohan, V.; 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 (CBIR)...

  13. Retrieving Land Surface Temperature from Hyperspectral Thermal Infrared Data Using a Multi-Channel Method.

    Science.gov (United States)

    Zhong, Xinke; Huo, Xing; Ren, Chao; Labed, Jelila; Li, Zhao-Liang

    2016-01-01

    Land Surface Temperature (LST) is a key parameter in climate systems. The methods for retrieving LST from hyperspectral thermal infrared data either require accurate atmospheric profile data or require thousands of continuous channels. We aim to retrieve LST for natural land surfaces from hyperspectral thermal infrared data using an adapted multi-channel method taking Land Surface Emissivity (LSE) properly into consideration. In the adapted method, LST can be retrieved by a linear function of 36 brightness temperatures at Top of Atmosphere (TOA) using channels where LSE has high values. We evaluated the adapted method using simulation data at nadir and satellite data near nadir. The Root Mean Square Error (RMSE) of the LST retrieved from the simulation data is 0.90 K. Compared with an LST product from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on Meteosat, the error in the LST retrieved from the Infared Atmospheric Sounding Interferometer (IASI) is approximately 1.6 K. The adapted method can be used for the near-real-time production of an LST product and to provide the physical method to simultaneously retrieve atmospheric profiles, LST, and LSE with a first-guess LST value. The limitations of the adapted method are that it requires the minimum LSE in the spectral interval of 800-950 cm(-1) larger than 0.95 and it has not been extended for off-nadir measurements. PMID:27187408

  14. Retrieving Land Surface Temperature from Hyperspectral Thermal Infrared Data Using a Multi-Channel Method

    Directory of Open Access Journals (Sweden)

    Xinke Zhong

    2016-05-01

    Full Text Available Land Surface Temperature (LST is a key parameter in climate systems. The methods for retrieving LST from hyperspectral thermal infrared data either require accurate atmospheric profile data or require thousands of continuous channels. We aim to retrieve LST for natural land surfaces from hyperspectral thermal infrared data using an adapted multi-channel method taking Land Surface Emissivity (LSE properly into consideration. In the adapted method, LST can be retrieved by a linear function of 36 brightness temperatures at Top of Atmosphere (TOA using channels where LSE has high values. We evaluated the adapted method using simulation data at nadir and satellite data near nadir. The Root Mean Square Error (RMSE of the LST retrieved from the simulation data is 0.90 K. Compared with an LST product from the Spinning Enhanced Visible and Infrared Imager (SEVIRI on Meteosat, the error in the LST retrieved from the Infared Atmospheric Sounding Interferometer (IASI is approximately 1.6 K. The adapted method can be used for the near-real-time production of an LST product and to provide the physical method to simultaneously retrieve atmospheric profiles, LST, and LSE with a first-guess LST value. The limitations of the adapted method are that it requires the minimum LSE in the spectral interval of 800–950 cm−1 larger than 0.95 and it has not been extended for off-nadir measurements.

  15. Retrieving Land Surface Temperature from Hyperspectral Thermal Infrared Data Using a Multi-Channel Method

    Science.gov (United States)

    Zhong, Xinke; Huo, Xing; Ren, Chao; Labed, Jelila; Li, Zhao-Liang

    2016-01-01

    Land Surface Temperature (LST) is a key parameter in climate systems. The methods for retrieving LST from hyperspectral thermal infrared data either require accurate atmospheric profile data or require thousands of continuous channels. We aim to retrieve LST for natural land surfaces from hyperspectral thermal infrared data using an adapted multi-channel method taking Land Surface Emissivity (LSE) properly into consideration. In the adapted method, LST can be retrieved by a linear function of 36 brightness temperatures at Top of Atmosphere (TOA) using channels where LSE has high values. We evaluated the adapted method using simulation data at nadir and satellite data near nadir. The Root Mean Square Error (RMSE) of the LST retrieved from the simulation data is 0.90 K. Compared with an LST product from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on Meteosat, the error in the LST retrieved from the Infared Atmospheric Sounding Interferometer (IASI) is approximately 1.6 K. The adapted method can be used for the near-real-time production of an LST product and to provide the physical method to simultaneously retrieve atmospheric profiles, LST, and LSE with a first-guess LST value. The limitations of the adapted method are that it requires the minimum LSE in the spectral interval of 800–950 cm−1 larger than 0.95 and it has not been extended for off-nadir measurements. PMID:27187408

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

    Directory of Open Access Journals (Sweden)

    A.Kannan

    2010-11-01

    Full Text Available The present research scholars are having keen interest in doing their research activities in the area ofData mining all over the world. Especially, [13]Mining Image data is the one of the essential features inthis present scenario since image data plays vital role in every aspect of the system such as business formarketing, hospital for surgery, engineering for construction, Web for publication and so on. The otherarea in the Image mining system is the Content-Based Image Retrieval (CBIR which performs retrievalbased on the similarity defined in terms of extracted features with more objectiveness. The drawback inCBIR is the features of the query image alone are considered. Hence, a new technique called Imageretrieval based on optimum clusters is proposed for improving user interaction with image retrievalsystems by fully exploiting the similarity information. The index is created by describing the imagesaccording to their color characteristics, with compact feature vectors, that represent typical colordistributions [12].

  17. Evaluation of Semantic-Based Information Retrieval Methods in the Autism Phenotype Domain

    OpenAIRE

    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...

  18. A content-based image retrieval method for optical colonoscopy images based on image recognition techniques

    Science.gov (United States)

    Nosato, Hirokazu; Sakanashi, Hidenori; Takahashi, Eiichi; Murakawa, Masahiro

    2015-03-01

    This paper proposes a content-based image retrieval method for optical colonoscopy images that can find images similar to ones being diagnosed. Optical colonoscopy is a method of direct observation for colons and rectums to diagnose bowel diseases. It is the most common procedure for screening, surveillance and treatment. However, diagnostic accuracy for intractable inflammatory bowel diseases, such as ulcerative colitis (UC), is highly dependent on the experience and knowledge of the medical doctor, because there is considerable variety in the appearances of colonic mucosa within inflammations with UC. In order to solve this issue, this paper proposes a content-based image retrieval method based on image recognition techniques. The proposed retrieval method can find similar images from a database of images diagnosed as UC, and can potentially furnish the medical records associated with the retrieved images to assist the UC diagnosis. Within the proposed method, color histogram features and higher order local auto-correlation (HLAC) features are adopted to represent the color information and geometrical information of optical colonoscopy images, respectively. Moreover, considering various characteristics of UC colonoscopy images, such as vascular patterns and the roughness of the colonic mucosa, we also propose an image enhancement method to highlight the appearances of colonic mucosa in UC. In an experiment using 161 UC images from 32 patients, we demonstrate that our method improves the accuracy of retrieving similar UC images.

  19. 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. PMID:22195112

  20. 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.

  1. Predominant Vocal Pitch Detection Method for Content Based Retrieval of Polyphonic Music

    Directory of Open Access Journals (Sweden)

    Nilima N. Patil,

    2012-09-01

    Full Text Available In the area of multimedia databases searching techniques of multimedia data is in focus in recent years. As more focus is given on the content-based retrieval of image and video data, less attention was received to the content-based retrieval of audio data. Most research based on monophonic musical sequences. In this approach, a system is developed for retrieval of polyphonic music retrieval system. A method for retrieving polyphonic music files using the pitch dimensions of music information is introduced. This method focuses on retrieval of content-based polyphonic music objects in Wav format. The goal is to build a software application ,CBAR(Content Base Audio Retrieval, for content based searching of musical databases via an user interface that uses music in a aural form familiar to the user, for both search-query construction and to display results. The query interface will allow the user to send a query item which appears to him as an extract from a piece of music to be matched by the system. Results will be returned as a list of complete pieses which contain the query item, or as locations within a specified piece or collection of pieces. The user will be able to test the results, and monitor the result by audio playback at any time. To search for a given file in the audio database , the user will input sample audio that indicate the information needed. A match score is then computed between the query and each of the database files. The user is then presented with a ranked list of the matching audio files. The match score does not requires entire audio to be present in the sample audio, but rather forms a query/message correlation score. The retrieval system’s user interface presents the matching score graphically so that required audio may be quickly identified.

  2. 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

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

    Science.gov (United States)

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

    2016-03-01

    One of the most important aims of astronomical data mining is to systematically search for specific rare objects in a massive spectral data set, given a small fraction of identified samples with the same type. Most existing methods are mainly based on binary classification, which usually suffers from incompleteness when there are too few known samples. Rank-based methods could provide good solutions for such cases. After investigating several algorithms, a method combining a bipartite ranking model with bootstrap aggregating techniques was developed in this paper. The method was applied while searching for carbon stars in the spectral data of Sloan Digital Sky Survey Data Release 10 and compared with several other popular methods used for data mining. Experimental results validate that the proposed method is not only the most effective but also the least time-consuming technique among its competitors when searching for rare spectra in a large but unlabeled data set.

  4. Evaluation of a content-based retrieval system for blood cell images with automated methods.

    Science.gov (United States)

    Seng, Woo Chaw; Mirisaee, Seyed Hadi

    2011-08-01

    Content-based image retrieval techniques have been extensively studied for the past few years. With the growth of digital medical image databases, the demand for content-based analysis and retrieval tools has been increasing remarkably. Blood cell image is a key diagnostic tool for hematologists. An automated system that can retrieved relevant blood cell images correctly and efficiently would save the effort and time of hematologists. The purpose of this work is to develop such a content-based image retrieval system. Global color histogram and wavelet-based methods are used in the prototype. The system allows users to search by providing a query image and select one of four implemented methods. The obtained results demonstrate the proposed extended query refinement has the potential to capture a user's high level query and perception subjectivity by dynamically giving better query combinations. Color-based methods performed better than wavelet-based methods with regard to precision, recall rate and retrieval time. Shape and density of blood cells are suggested as measurements for future improvement. The system developed is useful for undergraduate education. PMID:20703533

  5. 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.

  6. 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. PMID:25227014

  7. 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 improve...

  8. 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...

  9. Comparing different methods to assess weaver ant abundance in plantation trees

    DEFF Research Database (Denmark)

    Wargui, Rosine; Offenberg, Joachim; Sinzogan, Antonio;

    2015-01-01

    Weaver ants (Oecophylla spp.) are widely used as effective biological control agents. In order to optimize their use, ant abundance needs to be tracked. As several methods have been used to estimate ant abundance on plantation trees, abundances are not comparable between studies and no guideline is...... available on which method to apply in a particular study. This study compared four existing methods: three methods based on the number of ant trails on the main branches of a tree (called the Peng 1, Peng 2 and Offenberg index) and one method based on the number of ant nests per tree. Branch indices did not...... produce equal scores and cannot be compared directly. The Peng 1 index was the fastest to assess, but showed only limited seasonal fluctuations when ant abundance was high, because it approached its upper limit. The Peng 2 and Offenberg indices were lower and not close to the upper limit and therefore...

  10. 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.

  11. Information retrieval methods for high resolution γ-ray spectra

    International Nuclear Information System (INIS)

    A program based on MATLAB 7.0 platform was developed to locate characteristic peak position and calculate net area of characteristic peak. The formula for the calculation of relative standard deviation of net peak area by Sterlinski's method was found excellent in searching single peaks and resolving overlapping peaks in high resolution gamma-ray spectrum. Gaussian function fitting method using Levenberg-Marquardt algorithm was applied to calculate net area of peaks. A standard test spectrum supplied by the IAEA in 1995 was analyzed by the program and another two widely used commercial software. The analysis results show the program was superior to the latter two in searching single peaks and resolving overlapping peaks. The optimized fitting indexes are found between 0.962 and 0.996, which shows that the program adopted is feasible and accurate for extracting the net peak area in high resolution gamma-ray spectra. (authors)

  12. A Diminution Method of Large Multi-dimensional Data Retrievals

    OpenAIRE

    Nushwan Yousif Baithoon

    2010-01-01

    The intention of this work is to introduce a method ofcompressing data at the transmitter (source) and expanding it atthe receiver (destination).The amount of data compression is directly related to datadimensionality, hence, for example an N by N RGB image file isconsidered to be an M-D, with M=3, image data file.Also, the amount of scatter in an M-D file, hence, the covariancematrix is calculated, along with the average value of eachdimension, to represent the signature or code for each ind...

  13. 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.

  14. A Diminution Method of Large Multi-dimensional Data Retrievals

    Directory of Open Access Journals (Sweden)

    Nushwan Yousif Baithoon

    2010-01-01

    Full Text Available The intention of this work is to introduce a method ofcompressing data at the transmitter (source and expanding it atthe receiver (destination.The amount of data compression is directly related to datadimensionality, hence, for example an N by N RGB image file isconsidered to be an M-D, with M=3, image data file.Also, the amount of scatter in an M-D file, hence, the covariancematrix is calculated, along with the average value of eachdimension, to represent the signature or code for each individualdata set to be sent by the source.At the destination random sets can test a particular receivedsignature so that only one set is acceptable thus giving thecorresponding intended set to be received.Sound results are obtained depending on the constrains beingimplemented. These constrains are user tolerant in so far as howwell tuned or rapid the information is to be processed for dataretrieval.The proposed method is well suited in application areas whereboth source and destination are communicating using the samesets of data files at each end. Also such a technique is feasible forthe availability of fast microprocessors and frame-grabbers.

  15. 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

  16. Trace gas retrieval for limb DOAS under changing atmospheric conditions: The X-gas scaling method vs optimal estimation

    Science.gov (United States)

    Hueneke, Tilman; Grossmann, Katja; Knecht, Matthias; Raecke, Rasmus; Stutz, Jochen; Werner, Bodo; Pfeilsticker, Klaus

    2016-04-01

    Changing atmospheric conditions during DOAS measurements from fast moving aircraft platforms pose a challenge for trace gas retrievals. Traditional inversion techniques to retrieve trace gas concentrations from limb scattered UV/vis spectroscopy, like optimal estimation, require a-priori information on Mie extinction (e.g., aerosol concentration and cloud cover) and albedo, which determine the atmospheric radiative transfer. In contrast to satellite applications, cloud filters can not be applied because they would strongly reduce the usable amount of expensively gathered measurement data. In contrast to ground-based MAX-DOAS applications, an aerosol retrieval based on O4 is not able to constrain the radiative transfer in air-borne applications due to the rapidly decreasing amount of O4 with altitude. Furthermore, the assumption of a constant cloud cover is not valid for fast moving aircrafts, thus requiring 2D or even 3D treatment of the radiative transfer. Therefore, traditional techniques are not applicable for most of the data gathered by fast moving aircraft platforms. In order to circumvent these limitations, we have been developing the so-called X-gas scaling method. By utilising a proxy gas X (e.g. O3, O4, …), whose concentration is either a priori known or simultaneously in-situ measured as well as remotely measured, an effective absorption length for the target gas is inferred. In this presentation, we discuss the strengths and weaknesses of the novel approach along with some sample cases. A particular strength of the X-gas scaling method is its insensitivity towards the aerosol abundance and cloud cover as well as wavelength dependent effects, whereas its sensitivity towards the profiles of both gases requires a priori information on their shapes.

  17. Application of some Retrieved Information Method on Internet

    Directory of Open Access Journals (Sweden)

    Vu Thanh Nguyen

    2010-11-01

    Full Text Available This paper compares several methods of information extraction on the internet. Today, internet has become a treasure of knowledge. Every year, thousands of pieces of different information are posted on the internet. So, extracted information on the internet for many different purposes has become an important problem today. Users may extract information based on some available tools such as Lapis, Risk, Rapier, Wien, and Stalker. However, these tools have a disadvantage: we must update the training data when the website changes. So SVM and CRF associated with natural language processing are the best solutions to solve this problem. Information extraction from online Vietnamese news website with SVM and CRF brings experiment results that is very optimistic. Its results reach nearly 90% of the accuracy in websites and the processing time is less than one minute per site when the specified number of link levels is 1 within the base site.

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

    DEFF Research Database (Denmark)

    Sturm, Bob L.

    2014-01-01

    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...

  19. A method for estimating abundance of mobile populations using telemetry and counts of unmarked animals

    Science.gov (United States)

    Clement, Matthew; O'Keefe, Joy M; Walters, Brianne

    2015-01-01

    While numerous methods exist for estimating abundance when detection is imperfect, these methods may not be appropriate due to logistical difficulties or unrealistic assumptions. In particular, if highly mobile taxa are frequently absent from survey locations, methods that estimate a probability of detection conditional on presence will generate biased abundance estimates. Here, we propose a new estimator for estimating abundance of mobile populations using telemetry and counts of unmarked animals. The estimator assumes that the target population conforms to a fission-fusion grouping pattern, in which the population is divided into groups that frequently change in size and composition. If assumptions are met, it is not necessary to locate all groups in the population to estimate abundance. We derive an estimator, perform a simulation study, conduct a power analysis, and apply the method to field data. The simulation study confirmed that our estimator is asymptotically unbiased with low bias, narrow confidence intervals, and good coverage, given a modest survey effort. The power analysis provided initial guidance on survey effort. When applied to small data sets obtained by radio-tracking Indiana bats, abundance estimates were reasonable, although imprecise. The proposed method has the potential to improve abundance estimates for mobile species that have a fission-fusion social structure, such as Indiana bats, because it does not condition detection on presence at survey locations and because it avoids certain restrictive assumptions.

  20. Inter-comparison of stratospheric O3 and NO2 abundances retrieved from balloon borne direct sun observations and Envisat/SCIAMACHY limb measurements

    Directory of Open Access Journals (Sweden)

    A. Butz

    2006-01-01

    Full Text Available Stratospheric O3 and NO2 abundances measured by different remote sensing instruments are inter-compared: (1 Line-of-sight absorptions and vertical profiles inferred from solar spectra in the ultra-violet (UV, visible and infrared (IR wavelength ranges measured by the LPMA/DOAS (Limb Profile Monitor of the Atmosphere/Differential Optical Absorption Spectroscopy balloon payload during balloon ascent/descent and solar occultation are examined with respect to internal consistency. (2 The balloon borne stratospheric profiles of O3 and NO2 are compared to collocated space-borne skylight limb observations of the Envisat/SCIAMACHY satellite instrument. The trace gas profiles are retrieved from SCIAMACHY spectra using different algorithms developed at the Universities of Bremen and Heidelberg and at the Harvard-Smithsonian Center for Astrophysics. A comparison scheme is used that accounts for the spatial and temporal mismatch as well as differing photochemical conditions between the balloon and satellite borne measurements. It is found that the balloon borne measurements internally agree to within ±10% and ±20% for O3 and NO2, respectively, whereas the agreement with the satellite is ±20% for both gases in the 20 km to 30 km altitude range and in general worse below 20 km.

  1. 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.

  2. Term conflation methods in information retrieval: non-linguistic and linguistic approaches

    OpenAIRE

    Galvez, Carmen; Felix de Moya-Anegon, Felix; Herrero-Solana, Victor

    2005-01-01

    Purpose – To propose a categorization of the different conflation procedures at the two basic approaches, non-linguistic and linguistic techniques, and to justify the application of normalization methods within the framework of linguistic techniques. Design/methodology/approach – Presents a range of term conflation methods, that can be used in information retrieval. The uniterm and multiterm variants can be considered equivalent units for the purposes of automatic indexing. Stemming algor...

  3. 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.

  4. Arabo-AndalusianZellijImages RetrievalMethod Based on the Maximum Common Sub-graph

    OpenAIRE

    F. Touzani; Harti, M.; R.BENSLIMANE

    2012-01-01

    This paper describes a new indexing and retrieval method that can be used for indexing an Arabo-Andalusianpattern imagesdatabase where each image is characterized by its zellij Tiles (elementary shape) and their spatial relationship. The proposed method allows representingthis spatial relationship by an adjacency graph, itself represented by an adjacency matrix. The search of patterns similar to a given one presented as a query is then realized by calculating a similarity index characterizing...

  5. A multiparameter aerosol classification method and its application to retrievals from spaceborne polarimetry

    Science.gov (United States)

    Russell, Philip B.; Kacenelenbogen, Meloë; Livingston, John M.; Hasekamp, Otto P.; Burton, Sharon P.; Schuster, Gregory L.; Johnson, Matthew S.; Knobelspiesse, Kirk D.; Redemann, Jens; Ramachandran, S.; Holben, Brent

    2014-08-01

    Classifying observed aerosols into types (e.g., urban-industrial, biomass burning, mineral dust, maritime) helps to understand aerosol sources, transformations, effects, and feedback mechanisms; to improve accuracy of satellite retrievals; and to quantify aerosol radiative impacts on climate. The number of aerosol parameters retrieved from spaceborne sensors has been growing, from the initial aerosol optical depth (AOD) at one or a few wavelengths to a list that now includes AOD, complex refractive index, single scattering albedo (SSA), and depolarization of backscatter, each at several wavelengths, plus several particle size and shape parameters. Making optimal use of these varied data products requires objective, multidimensional analysis methods. We describe such a method, which makes explicit use of uncertainties in input parameters. It treats an N-parameter retrieved data point and its N-dimensional uncertainty as an extended data point, E. It then uses a modified Mahalanobis distance, DEC, to assign an observation to the class (cluster) C that has minimum DEC from the point. We use parameters retrieved from the Aerosol Robotic Network (AERONET) to define seven prespecified clusters (pure dust, polluted dust, urban-industrial/developed economy, urban-industrial/developing economy, dark biomass smoke, light biomass smoke, and pure marine), and we demonstrate application of the method to a 5 year record of retrievals from the spaceborne Polarization and Directionality of the Earth's Reflectances 3 (POLDER 3) polarimeter over the island of Crete, Greece. Results show changes of aerosol type at this location in the eastern Mediterranean Sea, which is influenced by a wide variety of aerosol sources.

  6. A Multi-Parameter Aerosol Classification Method and its Application to Retrievals from Spaceborne Polarimetry

    Science.gov (United States)

    Russell, P. B.; Kacenelenbogen, M. S.; Livingston, J. M.; Hasekamp, O. P.; Burton, S. P.; Schuster, G. L.; Johnson, M. S.; Knobelspiesse, K. D.; Redemann, J.; Ramachandran, S.; Holben, B. N.

    2014-12-01

    Classifying observed aerosols into types (e.g., urban-industrial, biomass burning, mineral dust, maritime) helps to understand aerosol sources, transformations, effects, and feedback mechanisms; to improve accuracy of satellite retrievals; and to quantify aerosol radiative impacts on climate. The number of aerosol parameters retrieved from spaceborne sensors has been growing, from the initial aerosol optical depth (AOD) at one or a few wavelengths to a list that now includes AOD, complex refractive index, single scattering albedo (SSA), and depolarization of backscatter, each at several wavelengths, plus several particle size and shape parameters. Making optimal use of these varied data products requires objective, multi-dimensional analysis methods. We describe such a method, which makes explicit use of uncertainties in input parameters. It treats an N-parameter retrieved data point and its N-dimensional uncertainty as an extended data point, E. It then uses a modified Mahalanobis distance, DEC, to assign an observation to the class (cluster) C that has minimum DEC from the point. We use parameters retrieved from the Aerosol Robotic Network (AERONET) to define seven prespecified clusters (pure dust, polluted dust, urban-industrial/developed economy, urban-industrial/developing economy, dark biomass smoke, light biomass smoke, pure marine), and we demonstrate application of the method to a 5-year record of retrievals from the spaceborne POLDER-3 (Polarization and Directionality of the Earth's Reflectances) polarimeter over the island of Crete, Greece. Results show changes of aerosol type at this location in the eastern Mediterranean Sea, which is influenced by a wide variety of aerosol sources.

  7. Determination of 235U isotope abundance by difference method of fission yield

    International Nuclear Information System (INIS)

    Background: Determination of the uranium isotope abundance ratio of fuel pins is a significant stage for the quality control in safe operations of reactor. Purpose: The aim is to establish a method to examine the 235U abundance of fuel rod with fast neutron as an excitation source. Methods: Taking the fission-yield ratios of Y-bar88Rb/Y-bar104Tc and Y-bar92Sr/Y-bar104Tc as the subjects of research, the relation curves between the average yield ratios and the 235U isotopic abundance as well as the expressions Y-bar1/Y-bar2=f(H0), in which the average yield ratio (Y-bari/Y-barj ) is a function of the 235U isotopic abundance (H0), were obtained and presented based on the previous studies. Results: In order to testify the accuracy of the method, the simulation sample of 72.2% is measured by working curve, and RSD is less than 2%. Within the limit of error, the results of sample analysis are in correspondence with those of passive gamma ray method. Conclusion: All of these results indicate that the method is feasible to determine the 235U abundance of fuel rod. (authors)

  8. 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...

  9. A sulphur abundance study of NGC 300 by an empirical calibration method

    CERN Document Server

    Christensen, T; Gammelgaard, P; Christensen, Tina; Petersen, Lars; Gammelgaard, Peter

    1996-01-01

    We propose an empirical sulphur abundance determination method based on the strong sulphur emission lines, [S II] 6716, 6731 and [S III] 9069, 9531 in H II regions. From a compilation of literature data we have made a calibration of sulphur abundance versus ([S II] + [S III])/Hbeta, similar to what has been widely used for the more easily observable iso-electronic element oxygen. This enables abundance determinations in extragalactic H II regions without measurements of weak temperature sensitive lines for use in model calculations. As a first application of the empirical calibration 15 spectra covering the wavelength range 3650-10000 AA have been obtained of H II regions at various galactocentric distances in the spiral galaxy NGC 300, by employing specially designed multiaperture slitmasks which allow simultaneous observations of several H II regions. Sulphur and oxygen abundances are determined and an oxygen gradient in agreement with previously published work is found as well as a somewhat steeper sulphur...

  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. Methods of semen collection not based on masturbation or surgical sperm retrieval.

    Science.gov (United States)

    Gerris, J

    1999-01-01

    Although masturbation is the standard method for the collection of a sperm sample, both for diagnostic and therapeutic purposes, other approaches have been described and assessed. Production of semen using specially designed condoms has been shown to result in samples with better laboratory characteristics than samples obtained after masturbation or coitus interruptus. However, this has not resulted in a general acceptance and use of this approach, except in special circumstances where masturbation is impossible or unacceptable. Direct retrieval of spermatozoa from morning urine is another method which has been used to study spermache in boys, but not to treat infertility. Sperm production techniques such as vibro- and electrostimulation are dealt with elsewhere, as are surgical retrieval techniques used in azoospermia.

  12. 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.

  13. Development and application of new methods to retrieve vertical structure of precipitation above the ARM CART sites from MMCR measurements

    Energy Technology Data Exchange (ETDEWEB)

    Matrosov, Sergey

    2010-12-15

    The main objective of this project was to develop, validate and apply remote sensing methods to retrieve vertical profiles of precipitation over the DOE ARM CART sites using currently available remote sensors. While the ARM Program invested very heavily into developments of remote sensing methods and instruments for water vapor and non-precipitating cloud parameter retrievals, precipitation retrievals and studies lagged behind. Precipitation, however, is a crucial part of the water cycle, and without detailed information on rainfall and snowfall, significant improvements in the atmospheric models of different scales (i.e., one of the ARM Program's main goals) is difficult to achieve. Characterization of the vertical atmospheric column above the CART sites is also incomplete without detailed precipitation information, so developments of remote sensing methods for retrievals of parameters in precipitating cloud condition was essential. Providing modelers with retrieval results was also one of the key objectives of this research project.

  14. 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…

  15. 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.

  16. 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.

  17. Improved Quality of MODIS Sea Surface Temperature Retrieval and Data Coverage Using Physical Deterministic Methods

    Directory of Open Access Journals (Sweden)

    Prabhat K. Koner

    2016-05-01

    Full Text Available Sea surface temperature (SST retrievals from satellite imager measurements are often performed using only two or three channels, and employ a regression methodology. As there are 16 thermal infrared (IR channels available for MODIS, we demonstrate a new SST retrieval methodology using more channels and a physically deterministic method, the modified total least squares (MTLS, to improve the quality of SST. Since cloud detection is always a part of any parameter estimation from IR satellite measurements, we hereby extend our recently-published novel cloud detection technique, which is based on both functional spectral differences and radiative transfer modeling for GOES-13. We demonstrate that the cloud detection coefficients derived for GOES-13 are working well for MODIS, while further improvements are made possible by the extra channels replacing some of the previous tests. The results are compared with available operational MODIS SST through the Group for High Resolution SST website–the data themselves are originally processed by the NASA Goddard Ocean Biology Processing Group. It is observed the data coverage can be more than doubled compared to the currently-available operational product, and at the same time the quality can be improved significantly. Two other SST retrieval methods, offline-calculated coefficients using the same form of the operational regression equation, and radiative transfer based optimal estimation, are included for comparison purposes.

  18. An incremental DPMM-based method for trajectory clustering, modeling, and retrieval.

    Science.gov (United States)

    Hu, Weiming; Li, Xi; Tian, Guodong; Maybank, Stephen; Zhang, Zhongfei

    2013-05-01

    Trajectory analysis is the basis for many applications, such as indexing of motion events in videos, activity recognition, and surveillance. In this paper, the Dirichlet process mixture model (DPMM) is applied to trajectory clustering, modeling, and retrieval. We propose an incremental version of a DPMM-based clustering algorithm and apply it to cluster trajectories. An appropriate number of trajectory clusters is determined automatically. When trajectories belonging to new clusters arrive, the new clusters can be identified online and added to the model without any retraining using the previous data. A time-sensitive Dirichlet process mixture model (tDPMM) is applied to each trajectory cluster for learning the trajectory pattern which represents the time-series characteristics of the trajectories in the cluster. Then, a parameterized index is constructed for each cluster. A novel likelihood estimation algorithm for the tDPMM is proposed, and a trajectory-based video retrieval model is developed. The tDPMM-based probabilistic matching method and the DPMM-based model growing method are combined to make the retrieval model scalable and adaptable. Experimental comparisons with state-of-the-art algorithms demonstrate the effectiveness of our algorithm. PMID:23520251

  19. 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.

  20. Isoline retrieval: An optimal sounding method for validation of advected contours

    CERN Document Server

    Mills, Peter

    2012-01-01

    The study of chaotic mixing is important for its potential to improve our understanding of fluid systems. Contour advection simulations provide a good model of the phenomenon by tracking the evolution of one or more contours or isolines of a trace substance to a high level of precision. The most accurate method of validating an advected contour is to divide the tracer concentration into discrete ranges and perform a maximum likelihood classification, a method that we term, "isoline retrieval." Conditional probabilities generated as a result provide excellent error characterization. In this study, a water vapour isoline of 0.001 mass-mixing-ratio is advected over five days in the upper troposphere and compared with high-resolution AMSU (Advanced Microwave Sounding Unit) satellite retrievals. The goal is to find the same fine-scale, chaotic mixing in the isoline retrievals as seen in the advection simulations. Some of the filaments generated by the simulations show up in the conditional probabilities as areas o...

  1. 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.

  2. 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.

  3. Retrieval procedure for time-resolved near-infrared tissue spectroscopy based on the optimal estimation method

    International Nuclear Information System (INIS)

    We propose the use of a retrieval procedure for time-resolved near-infrared tissue spectroscopy based on the ‘optimal estimation’ method. The aim of this retrieval method is to obtain an improved estimate of the target parameters compared with standard nonlinear least-squares routines, since the inverse problem dedicated to retrieve the optical properties of tissue is ill posed. A priori information on target and forward model parameters is used, so that a larger number of target parameters can be retrieved, and/or a better accuracy and precision can be achieved on the retrieved target parameters. The procedure has been tested on time-resolved simulated experiments generated, using solutions of the diffusion equation and with solutions of the radiative transfer equation reconstructed with Monte Carlo simulations. The results obtained show that, by using a priori information on target parameters, we have a smaller difference between retrieved values and true values, and lower retrieved error bars. Similarly, a more correct estimate of the errors of the forward model parameters improves the retrieval of the target parameters. (paper)

  4. 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.

  5. Physical retrieval of precipitation water contents from Special Sensor Microwave/Imager (SSM/I) data. Part 2: Retrieval method and applications (report version)

    Science.gov (United States)

    Olson, William S.

    1990-01-01

    A physical retrieval method for estimating precipitating water distributions and other geophysical parameters based upon measurements from the DMSP-F8 SSM/I is developed. Three unique features of the retrieval method are (1) sensor antenna patterns are explicitly included to accommodate varying channel resolution; (2) precipitation-brightness temperature relationships are quantified using the cloud ensemble/radiative parameterization; and (3) spatial constraints are imposed for certain background parameters, such as humidity, which vary more slowly in the horizontal than the cloud and precipitation water contents. The general framework of the method will facilitate the incorporation of measurements from the SSMJT, SSM/T-2 and geostationary infrared measurements, as well as information from conventional sources (e.g., radiosondes) or numerical forecast model fields.

  6. 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...

  7. 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.

  8. Chemical abundances of Damped Ly alpha systems A new method for estimating dust depletion effects

    CERN Document Server

    Vladilo, G

    2002-01-01

    A new method is presented for recovering the abundances of Damped Ly alpha systems (DLAs) taking into account the effects of dust depletion. For the first time, possible variations of the chemical composition of the dust are taken into account in estimating the depletions. No prior assumptions on the extinction properties of the dust are required. The method requires a set of abundances measured in the gas and a set of parameters describing the chemical properties of the dust. A large subset of these parameters is determined from interstellar observations; the others are free parameters for which an educated guess can be made. The method is able to recover the abundances of the SMC starting from SMC interstellar measurements apparently discrepant from the stellar ones. Application of the method to 22 DLAs with available [Fe/H] and [Si/Fe] measurements gives the following results: (1) the mean metallicity of the corrected data is ~ -1.0 dex, about 0.5 dex higher than that of the original data; (2) the slope o...

  9. 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 https://github.com/nyusngroup/pyMCZ.

  10. An online aerosol retrieval algorithm using OMI near-UV observations based on the optimal estimation method

    Directory of Open Access Journals (Sweden)

    U. Jeong

    2015-06-01

    Full Text Available An online version of the OMI (Ozone Monitoring Instrument near-ultraviolet (UV aerosol retrieval algorithm was developed to retrieve aerosol optical thickness (AOT and single scattering albedo (SSA based on the optimal estimation (OE method. Instead of using the traditional look-up tables for radiative transfer calculations, it performs online radiative transfer calculations with the Vector Linearized Discrete Ordinate Radiative Transfer (VLIDORT model to eliminate interpolation errors and improve stability. The OE-based algorithm has the merit of providing useful estimates of uncertainties simultaneously with the inversion products. The measurements and inversion products of the Distributed Regional Aerosol Gridded Observation Network campaign in Northeast Asia (DRAGON NE-Asia 2012 were used to validate the retrieved AOT and SSA. The retrieved AOT and SSA at 388 nm have a correlation with the Aerosol Robotic Network (AERONET products that is comparable to or better than the correlation with the operational product during the campaign. The estimated retrieval noise and smoothing error perform well in representing the envelope curve of actual biases of AOT at 388 nm between the retrieved AOT and AERONET measurements. The forward model parameter errors were analyzed separately for both AOT and SSA retrievals. The surface albedo at 388 nm, the imaginary part of the refractive index at 354 nm, and the number fine mode fraction (FMF were found to be the most important parameters affecting the retrieval accuracy of AOT, while FMF was the most important parameter for the SSA retrieval. The additional information provided with the retrievals, including the estimated error and degrees of freedom, is expected to be valuable for future studies.

  11. Chemical abundances of damped Ly alpha systems:. A new method for estimating dust depletion effects

    Science.gov (United States)

    Vladilo, G.

    2002-08-01

    A new method is presented for recovering the abundances of Damped Ly alpha systems (DLAs) taking into account the effects of dust depletion. For the first time, possible variations of the chemical composition of the dust are taken into account in estimating the depletions. No prior assumptions on the extinction properties of the dust are required. The method requires a set of abundances measured in the gas and a set of parameters describing the chemical properties of the dust. A large subset of these parameters is determined from interstellar observations; the others are free parameters for which an educated guess can be made. The method is able to recover the abundances of the SMC starting from SMC interstellar measurements apparently discrepant from the stellar ones. Application of the method to 22 DLAs with available [Fe/H] and [Si/Fe] measurements gives the following results: (1) the mean metallicity of the corrected data is =~ -1.0 dex, about 0.5 dex higher than that of the original data; (2) the slope of the [Fe/H] versus redshift relation is steeper for the corrected data (m =~ -0.3 dex) than for the original ones (m =~ -0.2 dex); (3) the corrected [Si/Fe] ratios are less enhanced, on average, than those found in Galactic stars of similar, low metallicity; (4) a decrease of the [Si/Fe] versus [Fe/H] ratios, expected by ``time delay'' models of chemical evolution, is found for the corrected data; (5) the [Si/Fe] ratios tend to increase with redshift once corrected; (6) consistency between [Si/Fe] and [S/Zn] measurements, two independent estimators of the alpha /Fe ratio, is found only for the corrected abundances.

  12. Methods of index calculation and presentation of fish abundance data using standard computer programs

    OpenAIRE

    Fotland, Åge; Mehl, Sigbjørn; Sunnanå, Knut

    1995-01-01

    Standard 0-group indices distribution maps are now produced based on hand-drawn maps using AutoCad with some additional procedures. This paper briefly describes the mathod. The paper further describes ways of importing coastlines and survey data directly into standard computer programs such as AUtoCad and SAS. Standard methods are used for gridding data, producing isolines and further calculation of abundance indices and presentation of distributions. Interactive editing of distribution maps ...

  13. 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

  14. Evaluation of shape indexing methods for content-based retrieval of x-ray images

    Science.gov (United States)

    Antani, Sameer; Long, L. Rodney; Thoma, George R.; Lee, Dah-Jye

    2003-01-01

    Efficient content-based image retrieval of biomedical images is a challenging problem of growing research interest. Feature representation algorithms used in indexing medical images on the pathology of interest have to address conflicting goals of reducing feature dimensionality while retaining important and often subtle biomedical features. At the Lister Hill National Center for Biomedical Communications, a R&D division of the National Library of Medicine, we are developing a content-based image retrieval system for digitized images of a collection of 17,000 cervical and lumbar x-rays taken as a part of the second National Health and Nutrition Examination Survey (NHANES II). Shape is the only feature that effectively describes various pathologies identified by medical experts as being consistently and reliably found in the image collection. In order to determine if the state of the art in shape representation methods is suitable for this application, we have evaluated representative algorithms selected from the literature. The algorithms were tested on a subset of 250 vertebral shapes. In this paper we present the requirements of an ideal algorithm, define the evaluation criteria, and present the results and our analysis of the evaluation. We observe that while the shape methods perform well on visual inspection of the overall shape boundaries, they fall short in meeting the needs of determining similarity between the vertebral shapes based on the pathology.

  15. 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.

  16. 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.

  17. An efficient and robutst method for shape-based image retrieval

    International Nuclear Information System (INIS)

    Shapes can be thought as being the words oft he visual language. Shape boundaries need to be simplified and estimated in a wide variety of image analysis applications. Representation and description of Shapes is one of the major problems in content-based image retrieval (CBIR). This paper present an a novel method for shape representation and description named block-based shape representation (BSR), which is capable of extracting reliable information of the object outline in a concise manner. Our technique is translation, scale, and rotation invariant. It works well on different types of shapes and fast enough for use in real-time. This technique has been implemented and evaluated in order to analyze its accuracy and Efficiency. Based on the experimental results, we urge that the proposed BSR is a compact and reliable shape representation method. (author)

  18. Tropospheric ozone retrieval by using SCIAMACHY Limb-Nadir-Matching method

    Science.gov (United States)

    Jia, Jia; Ladstätter-Weissenmayer, Annette; Ebojie, Felix; Rozanov, Alexei; Burrows, John

    2014-05-01

    Tropospheric ozone is photochemically produced during pollution events and transported from the stratosphere towards the troposphere. It is the third most important green house gases and the main component of summer smog. Global covered satellite measurements are well suitable to investigate sources, sinks, and transport mechanisms of tropospheric ozone in a global view, and to study a characteristic behaviour of the tropospheric ozone in regions. However, the usage of satellite data is associated to a large uncertainty as 90% ozone is located in the stratosphere and only the remaining part of 10% can be observed in the troposphere. The limb-nadir matching (LNM) technique is one of the methods suitable to retrieve tropospheric ozone distributions from space borne observations of the scattered solar light in the UV-visible spectral range. In this study we apply the LNM approach to alternating limb and nadir measurements performed by the SCIAMACHY instrument. A precise tropopause height is used to subtract the stratospheric ozone from the total ozone amount for each matching point. The focus of this work is to reduce the uncertainty of the resulting tropospheric ozone distributions by analysing possible error sources, refining both limb and nadir retrievals and the matching technique.

  19. Wind Profile Retrieval Method for Incoherent Doppler LIDAR in Partly Cloudy Conditions

    Science.gov (United States)

    Feng, Changzhong; Liu, Bingyi; Liu, Zhishen

    2014-11-01

    After the launch of ESA’s spaceborne Doppler lidar ALADIN, Ocean University of China is going to perform the ground validation using a ground based Doppler wind lidar which utilizes an iodine absorption filter as frequency discriminator to derive Doppler frequency shift of atmospheric wind from combined molecular and aerosol backscatter. Under circumstance of non-uniform aerosol horizontal distribution, such as partly cloudy conditions, the accuracy of wind measurements is seriously influenced. Therefore, an improved VAD (Velocity-Azimuth Display) method for retrieving wind profiles is developed, which significantly increases the accuracy. With the atmospheric return signal obtained from the line-of-sight velocity PPI (Plan Position Indicator) measurements, the spatial distribution of aerosol optical parameters can be derived and considered as a reference for the quality control of line-of-sight velocity. Consequently, the wind profile in partly cloudy conditions can be retrieved by using the quality controlled line-of-sight velocity. As a result, the applicability of the ground based Doppler lidar is improved.

  20. 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. PMID:26836078

  1. 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.

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

    International Nuclear Information System (INIS)

    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. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  3. 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.

  4. 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...

  5. Chiral retrieval method based on right circularly polarized and left circularly polarized waves

    International Nuclear Information System (INIS)

    The free-wave characterization of metamaterials is usually carried out by illuminating a sample with a linearly polarized plane electromagnetic wave. At points before and after the sample, sensors are introduced to measure the transverse components of the field, in order to compute the reflection and transmission coefficients related with the co- and cross-polar field components. Based on this information, retrieval algorithms allow parameters like rotation angle, effective chirality and refraction index to be calculated. Here we propose to use the transmission signals under illumination with plane circularly polarized waves, without sensing the reflection signal, to calculate the chirality parameter and the rotation angle due to the electromagnetic activity of the material. This new method, which allows a simpler characterization of a chiral slab, is applied to the study of metamaterials composed of both periodic and random distributions of metallic structures with chiral symmetry. The experimental results are contrasted with simulations and alternative measurements obtained using linearly polarized waves. (paper)

  6. An automatic Planetary Boundary Layer height retrieval method with compact EZ backscattering Lidar

    Science.gov (United States)

    Loaec, S.; Sauvage, L.; Boquet, M.; Lolli, S.; Rouget, V.

    2009-09-01

    Bigger strongly urbanized cities in the world are often exposed to atmospheric pollution events. To understand the chemical and physical processes that are taking place in these areas it is necessary to describe correctly the Planetary Boundary Layer (PBL) dynamics and the PBL height evolution. For these proposals, a compact and rugged eye safe UV Lidar, the EZLIDAR™, was developed together by CEA/LMD and LEOSPHERE (France) to study and investigate structural and optical properties of clouds and aerosols and PBL time evolution. EZLIDAR™ has been validated by different remote and in-situ instruments as MPL Type-4 Lidar manufactured by NASA at ARM/SGP site or the LNA (Lidar Nuage Aerosol) at the Laboratoire de Metereologie Dynamique LMD (France) and during several intercomparison campaigns. EZLIDAR™ algorithm retrieves automatically the PBL height in real-time. The method is based on the detection of the slope of the signal linked to a sharp change in concentration of the aerosols. Once detected, the different layers are filtered on a 15mn sample and classified between nocturnal, convective or residual layer, depending on the time and date. This method has been validated against those retrieved by the algorithm STRAT from data acquired at IPSL, France, showing 95% of correlation. In this paper are presented the results of the intercomparison campaign that took place in Orleans, France and Mace Head, Ireland in the framework of ICOS (Integrated Carbon Observation System) project, where the EZ Lidar™ worked under all weather conditions, clear sky, fog, low clouds, during the whole month of October 2008. Moreover, thanks to its 3D scanning capability, the EZLIDAR was able to provide the variability of the PBL height around the site, enabling the scientists to estimate the flux intensities that play a key role in the radiative transfer budget and in the atmospheric pollutants dispersion.

  7. 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.

  8. 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.

  9. Content based Image Retrieval based on Different Global and Local Color Histogram Methods: A Survey

    Science.gov (United States)

    Suhasini, Pallikonda Sarah; Sri Rama Krishna, K.; Murali Krishna, I. V.

    2016-06-01

    Different global and local color histogram methods for content based image retrieval (CBIR) are investigated in this paper. Color histogram is a widely used descriptor for CBIR. Conventional method of extracting color histogram is global, which misses the spatial content, is less invariant to deformation and viewpoint changes, and results in a very large three dimensional histogram corresponding to the color space used. To address the above deficiencies, different global and local histogram methods are proposed in recent research. Different ways of extracting local histograms to have spatial correspondence, invariant colour histogram to add deformation and viewpoint invariance and fuzzy linking method to reduce the size of the histogram are found in recent papers. The color space and the distance metric used are vital in obtaining color histogram. In this paper the performance of CBIR based on different global and local color histograms in three different color spaces, namely, RGB, HSV, L*a*b* and also with three distance measures Euclidean, Quadratic and Histogram intersection are surveyed, to choose appropriate method for future research.

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. Latent Semantic Analysis as a Method of Content-Based Image Retrieval in Medical Applications

    Science.gov (United States)

    Makovoz, Gennadiy

    2010-01-01

    The research investigated whether a Latent Semantic Analysis (LSA)-based approach to image retrieval can map pixel intensity into a smaller concept space with good accuracy and reasonable computational cost. From a large set of M computed tomography (CT) images, a retrieval query found all images for a particular patient based on semantic…

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Statistical methods for detecting differentially abundant features in clinical metagenomic samples.

    Directory of Open Access Journals (Sweden)

    James Robert White

    2009-04-01

    Full Text Available Numerous studies are currently underway to characterize the microbial communities inhabiting our world. These studies aim to dramatically expand our understanding of the microbial biosphere and, more importantly, hope to reveal the secrets of the complex symbiotic relationship between us and our commensal bacterial microflora. An important prerequisite for such discoveries are computational tools that are able to rapidly and accurately compare large datasets generated from complex bacterial communities to identify features that distinguish them.We present a statistical method for comparing clinical metagenomic samples from two treatment populations on the basis of count data (e.g. as obtained through sequencing to detect differentially abundant features. Our method, Metastats, employs the false discovery rate to improve specificity in high-complexity environments, and separately handles sparsely-sampled features using Fisher's exact test. Under a variety of simulations, we show that Metastats performs well compared to previously used methods, and significantly outperforms other methods for features with sparse counts. We demonstrate the utility of our method on several datasets including a 16S rRNA survey of obese and lean human gut microbiomes, COG functional profiles of infant and mature gut microbiomes, and bacterial and viral metabolic subsystem data inferred from random sequencing of 85 metagenomes. The application of our method to the obesity dataset reveals differences between obese and lean subjects not reported in the original study. For the COG and subsystem datasets, we provide the first statistically rigorous assessment of the differences between these populations. The methods described in this paper are the first to address clinical metagenomic datasets comprising samples from multiple subjects. Our methods are robust across datasets of varied complexity and sampling level. While designed for metagenomic applications, our software

  20. A Method of Case Retrieval for Web-based Remote Customization Platform

    Directory of Open Access Journals (Sweden)

    Yuhuai Wang

    2014-04-01

    Full Text Available A web-based remote customization platform is developed for hardware product in this paper. To realize the rapid product customization, a case-based reasoning approach based on fuzzy set is put forward. To retrieve the most similar case from the case base, a parabola membership function is constructed based on the fuzzy set, and synthesis weights are introduced by combining subjective weights with objective weights which are calculated based on the deviation information of similarity. Then the model for solving cases' global similarity is set up based on synthesis weights. To improve the accuracy of the similarity measurement, center distance revision method based on area is presented for the Bi-interval type which is one of fuzzy numeric attribute. Implementation example applying above methods is given in the area of electric drill customization. Results show that the presented approach helps to improve the accuracy of the similarity of the case product, and reduce the time and cost of product design process

  1. 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.

  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. Inter-comparison of stratospheric O3 and NO2 abundances retrieved from balloon borne direct sun observations and Envisat/SCIAMACHY limb measurements

    OpenAIRE

    A. Butz; H. Bösch; Camy-Peyret, C.; Chipperfield, M.; Dorf, M.; G. Dufour; Grunow, K.; Jeseck, P.; Kühl, S.; Payan, S.; Pepin, I.; Pukite, J.; Rozanov, A.(CPPM, Aix-Marseille Université and CNRS/IN2P3, Marseille, France); Savigny, C.; Sioris, C.

    2006-01-01

    Stratospheric O3 and NO2 abundances measured by different remote sensing instruments are inter-compared: (1) Line-of-sight absorptions and vertical profiles inferred from solar spectra in the ultra-violet (UV), visible and infrared (IR) wavelength ranges measured by the LPMA/DOAS (Limb Profile Monitor of the Atmosphere/Differential Optical Absorption Spectroscopy) balloon payload during balloon ascent/descent and solar occultation are examined with respect to interna...

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

    International Nuclear Information System (INIS)

    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 reverse-projection (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

  5. 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.

  6. 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.

  7. Novel Snow Depth Retrieval Method Using Time Series Ssmi Passive Microwave Imagery

    Science.gov (United States)

    Nikraftar, Z.; Hasanlou, M.; Esmaeilzadeh, M.

    2016-06-01

    The Special Sensor Microwave Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSM/IS) are satellites that work in passive microwave range. The SSM/I has capability to measure geophysical parameters which these parameters are key to investigate the climate and hydrology condition in the world. In this research the SSMI passive microwave data is used to study the feasibility of monitoring snow depth during snowfall month from 2010 to 2015 using an algorithm in conjunction with ground depth measured at meteorological stations of the National Centre for Environmental Information (NCEI). The previous procedures for snow depth retrieval algorithms uses only one or two passive bands for modelling snow depth. This study enable us to use of a nonlinear multidimensional regression algorithm which incorporates all channels and their related weighting coefficients for each band. Higher value of these coefficients are indicator of the importance of each band in the regression model. All channels and their combination were used in support of the vector algorithm combined with genetic algorithm (GA) for feature selection to estimate snow depth. The results were compared with those algorithms developed by recent researchers and the results clearly shows the superiority of proposed method (R2 = 0.82 and RMSE = 6.3 cm).

  8. An Improved Method to Retrieve Surface Emissivity in a Canary Pine Forest Using Aster Data

    Science.gov (United States)

    Barreto-Velasco, Africa; Hernandez-Leal, Pedro A.; Arbelo, Manuel; Podesta, Guillermo P.

    2012-07-01

    The widely-used Temperature and Emissivity Separation (TES) algorithm has been shown to provide reliable temperature and emissivity estimates from land-leaving thermal data. Nevertheless, TES has some important limitations mainly related to its inability to correct important inaccuracies for gray bodies, such as vegetation. In this study, this problem is addressed through an improvement to the current NEM (Normalized Emissivity Method) module included in the TES algorithm. The proposed method, called Modified NEM (ModNEM), has been specifically designed to retrieve an accurate surface emissivity for bodies with a spectral behavior typical of gray-bodies, i. e., flat and near spectrally invariant. ModNEM selects two different approximations of surface temperature instead of the usual maximum temperature, with the aim of accounting for the peculiar spectral behavior of brightness temperature and emissivity for vegetation. The NEM and TES, as well as the ModNEM, have been used to recover surface emissivity in a pine forest located in Tenerife Island (Canary Islands, Spain) using data from the Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER). Results have been compared and validated using reference emissivity values obtained from the pines by means of the box method. This validation study showed that high uncertainties are associated with the standard techniques (up to 0.034), whereas ModNEM results in lower uncertainties in emissivity estimates (NEM module are not suitable for surfaces with a spectral behavior similar to a grey body. This work was supported by MICINN under Grant CGL2010-22189-C02.

  9. 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.

  10. 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…

  11. A Novel Method to Assess Wear Rates of Retrieved Tibial Inserts Following in-vivo Use

    Science.gov (United States)

    Paniogue, Tanille J.

    Ultra-high molecular weight polyethylene (UHMWPE) on cobalt chrome is the bearing couple of choice for total knee arthroplasty. The number of patients undergoing total knee arthroplasty has been steadily growing and is projected to continue increasing rapidly in the near future. Many of these patients are younger and more active and therefore need a longer lasting device. However, many of these devices fail prematurely and often the primary reason for failure and ultimately revision is due to wear related issues. Therefore, examining how wear rates of the UHMWPE tibial insert change during in-vivo use can help elucidate the mechanisms of accelerated wear and hopefully aid in finding solutions to combat wear related failures. Different crosslinking treatments have been employed by manufacturers to improve wear resistance of the polyethylene. While this has been shown to be an effective way to reduce wear, crosslinking has led to other issues such as oxidative instability and a decline in mechanical properties. The purpose of this body of work is to examine how changes in oxidation, after in-vivo use, affect wear resistance. A novel testing method was developed to test the native articular surface from retrieved tibial inserts in a laboratory Pin-on-Disk (POD) simulator. The method was validated using short-duration implant articular surfaces and non-articular control pins. In the absence of high surface oxidation or severe surface damage, the articular surface pins had comparable steady state wear rates to their bulk counterparts. Tests of devices with longer in-vivo service show chemical changes consistent with a free-radical mediated oxidation mechanism. Tribological assessment of the articular surfaces shows increasing wear rates as a function of oxidation. While this relationship has been hypothesized in the literature, these experiments represent the first physical demonstration of the phenomenon. The wear mechanism is further explored through infrared

  12. Phase retrieval and norm retrieval

    OpenAIRE

    Bahmanpour, Saeid; Cahill, Jameson; Casazza, Peter G.; Jasper, John; Woodland, Lindsey M.

    2014-01-01

    Phase retrieval has become a very active area of research. We will classify when phase retrieval by Parseval frames passes to the Naimark complement and when phase retrieval by projections passes to the orthogonal complements. We introduce a new concept we call norm retrieval and show that this is what is necessary for passing phase retrieval to complements. This leads to a detailed study of norm retrieval and its relationship to phase retrieval. One fundamental result: a frame $\\{\\varphi_i\\}...

  13. 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.

  14. 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).

  15. 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.

  16. Contrasting ET-retrieval methods from remote sensing in a semiarid area (Southern Spain)

    Science.gov (United States)

    Martínez, José Angel; García Galiano, Sandra G.; Baille, Alain

    2013-04-01

    The study area of Campo de Cartagena, is located in the Segura River basin (South-East of Spain). This basin is characterized by strong climatic contrasts, frequent droughts and floods. These contrasts, in addition to the progressive increase in water demands associated with economic activities, land use and climate change, contribute to frequent water deficit situations. For these reasons, an important component in the energy and water balance is the evapotranspiration, particularly in these semi-arid areas where water deficiency is a major problem for the economic and sustainable welfare. Through interpretation of remote sensing data, applied to the Segura River Basin, indices and parameters establishing statistical relationships are identified: albedo, normalized difference vegetation index (NDVI), land surface emissivity and temperature (LST), and actual evapotranspiration (ET), among other variables. The proposed methodology allows the operational estimation of ET from Landsat-5 TM, for wide areas. Several corrections (radiometric and atmospheric) and cloud masks, were applied to the images. By incorporating a Digital Elevation Model (DEM) and topographical attributes, the spatial distribution of instantaneous ET (at satellite overpass) was derived considering a topographical correction of shortwave net radiation. Two residual algorithms were considered for retrieving ET: (i) a single-source model, based on the direct estimation of the evaporative fraction from the analysis of NDVI-LST space, and (ii) a dual-source model, named 'revised three temperature model' (3T-R model). The results from both methods were validated with flux towers observations at satellite overpass and at daily scale (24h). The two residual methods had low requirement of input data, making easier the operational assessment and implementation of ET mapping tools over large areas. The information below a GIS environment will allow the identification of spatiotemporal patterns of water

  17. 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...

  18. Information retrieval system on reactor test methods and role of methodic information in planning of research in reactor material science field

    International Nuclear Information System (INIS)

    The results of processing of methodic information which is systematized in form of an information retrieval system adapted for needs of researchers in material science field are represented. It permits to optimize planning of development and perfectioning the experimental base for reactor material science. (J.P.)

  19. 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.

  20. 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

  1. 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.

  2. Chilean blue whales as a case study to illustrate methods to estimate abundance and evaluate conservation status of rare species.

    Science.gov (United States)

    Williams, Rob; Hedley, Sharon L; Branch, Trevor A; Bravington, Mark V; Zerbini, Alexandre N; Findlay, Ken P

    2011-06-01

    Often abundance of rare species cannot be estimated with conventional design-based methods, so we illustrate with a population of blue whales (Balaenoptera musculus) a spatial model-based method to estimate abundance. We analyzed data from line-transect surveys of blue whales off the coast of Chile, where the population was hunted to low levels. Field protocols allowed deviation from planned track lines to collect identification photographs and tissue samples for genetic analyses, which resulted in an ad hoc sampling design with increased effort in areas of higher densities. Thus, we used spatial modeling methods to estimate abundance. Spatial models are increasingly being used to analyze data from surveys of marine, aquatic, and terrestrial species, but estimation of uncertainty from such models is often problematic. We developed a new, broadly applicable variance estimator that showed there were likely 303 whales (95% CI 176-625) in the study area. The survey did not span the whales' entire range, so this is a minimum estimate. We estimated current minimum abundance relative to pre-exploitation abundance (i.e., status) with a population dynamics model that incorporated our minimum abundance estimate, likely population growth rates from a meta-analysis of rates of increase in large baleen whales, and two alternative assumptions about historic catches. From this model, we estimated that the population was at a minimum of 9.5% (95% CI 4.9-18.0%) of pre-exploitation levels in 1998 under one catch assumption and 7.2% (CI 3.7-13.7%) of pre-exploitation levels under the other. Thus, although Chilean blue whales are probably still at a small fraction of pre-exploitation abundance, even these minimum abundance estimates demonstrate that their status is better than that of Antarctic blue whales, which are still <1% of pre-exploitation population size. We anticipate our methods will be broadly applicable in aquatic and terrestrial surveys for rarely encountered species

  3. 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.

  4. The retrieval of abnormal TL glow curves using modified glow curve analysis method

    International Nuclear Information System (INIS)

    The shape of TL glow curve is a useful indicator for assurance of correct reading of the personal dosimeter. Since the reading procedure of TLD is irreversible, however, an analytic remedy should be considered to procure reliable dosimetric information for the readings with irregular glow curve shape. In this study, kinetic trapping parameter of CaSO4 : Dy Teflon personal dosimeter (Teledyne PB-6A) were analyzed by Halperin and Braner's model for general-order kinetics. From these kinetic trapping parameters, we also developed a simple procedure to retrieve the dosimetric information from abnormally distorted glow curves. The computerized glow curve deconvolution (CGCD) fitting of the reference glow curve with kinetic parameters from this study yields relative errors of about 5% from the expected integral. It was also found that the glow curve remedial procedure developed could retrieve the distorted TL glow curves within error ranges of 15%. With the glow curve retrieval techniques, doses incurred by gamma radiation can now be successfully re-constructed for the CaSO4 : Dy Teflon dosimeter resulting abnormal glow curves. (author)

  5. De-noising and retrieving algorithm of Mie lidar data based on the particle filter and the Fernald method.

    Science.gov (United States)

    Li, Chen; Pan, Zengxin; Mao, Feiyue; Gong, Wei; Chen, Shihua; Min, Qilong

    2015-10-01

    The signal-to-noise ratio (SNR) of an atmospheric lidar decreases rapidly as range increases, so that maintaining high accuracy when retrieving lidar data at the far end is difficult. To avoid this problem, many de-noising algorithms have been developed; in particular, an effective de-noising algorithm has been proposed to simultaneously retrieve lidar data and obtain a de-noised signal by combining the ensemble Kalman filter (EnKF) and the Fernald method. This algorithm enhances the retrieval accuracy and effective measure range of a lidar based on the Fernald method, but sometimes leads to a shift (bias) in the near range as a result of the over-smoothing caused by the EnKF. This study proposes a new scheme that avoids this phenomenon using a particle filter (PF) instead of the EnKF in the de-noising algorithm. Synthetic experiments show that the PF performs better than the EnKF and Fernald methods. The root mean square error of PF are 52.55% and 38.14% of that of the Fernald and EnKF methods, and PF increases the SNR by 44.36% and 11.57% of that of the Fernald and EnKF methods, respectively. For experiments with real signals, the relative bias of the EnKF is 5.72%, which is reduced to 2.15% by the PF in the near range. Furthermore, the suppression impact on the random noise in the far range is also made significant via the PF. An extensive application of the PF method can be useful in determining the local and global properties of aerosols. PMID:26480164

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

    Directory of Open Access Journals (Sweden)

    Robert S Alonso

    Full Text Available 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

  7. An improved tropospheric ozone database retrieved from SCIAMACHY Limb-Nadir-Matching method

    Science.gov (United States)

    Jia, Jia; Rozanov, Alexei; Ladstätter-Weißenmayer, Annette; Ebojie, Felix; Rahpoe, Nabiz; Bötel, Stefan; Burrows, John

    2015-04-01

    Tropospheric ozone is one of the most important green-house gases and the main component of photochemical smog. It is either transported from the stratosphere or photochemically produced during pollution events in the troposphere that threaten the respiratory system. To investigate sources, transport mechanisms of tropospheric ozone in a global view, limb nadir matching (LNM) technique applied with SCIAMACHY instrument is used to retrieve tropospheric ozone. With the fact that 90% ozone is located in the stratosphere and only about 10% can be observed in the troposphere, the usage of satellite data requires highly qualified nadir and limb data. In this study we show an improvement of SCIAMACHY limb data as well as its influence on tropospheric ozone results. The limb nadir matching technique is also refined to increase the quality of the tropospheric ozone. The results are validated with ozone sonde measurements.

  8. 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.

  9. 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...... 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...

  10. Determining the Diversity and Species Abundance Patterns in Arctic Soils using Rational Methods for Exploring Microbial Diversity

    Science.gov (United States)

    Ovreas, L.; Quince, C.; Sloan, W.; Lanzen, A.; Davenport, R.; Green, J.; Coulson, S.; Curtis, T.

    2012-12-01

    Arctic microbial soil communities are intrinsically interesting and poorly characterised. We have inferred the diversity and species abundance distribution of 6 Arctic soils: new and mature soil at the foot of a receding glacier, Arctic Semi Desert, the foot of bird cliffs and soil underlying Arctic Tundra Heath: all near Ny-Ålesund, Spitsbergen. Diversity, distribution and sample sizes were estimated using the rational method of Quince et al., (Isme Journal 2 2008:997-1006) to determine the most plausible underlying species abundance distribution. A log-normal species abundance curve was found to give a slightly better fit than an inverse Gaussian curve if, and only if, sequencing error was removed. The median estimates of diversity of operational taxonomic units (at the 3% level) were 3600-5600 (lognormal assumed) and 2825-4100 (inverse Gaussian assumed). The nature and origins of species abundance distributions are poorly understood but may yet be grasped by observing and analysing such distributions in the microbial world. The sample size required to observe the distribution (by sequencing 90% of the taxa) varied between ~ 106 and ~105 for the lognormal and inverse Gaussian respectively. We infer that between 5 and 50 GB of sequencing would be required to capture 90% or the metagenome. Though a principle components analysis clearly divided the sites into three groups there was a high (20-45%) degree of overlap in between locations irrespective of geographical proximity. Interestingly, the nearest relatives of the most abundant taxa at a number of most sites were of alpine or polar origin. Samples plotted on first two principal components together with arbitrary discriminatory OTUs

  11. New method for isolating barophiles from intestinal contents of deep-sea fishes retrieved from the abyssal zone.

    Science.gov (United States)

    Nakayama, A; Yano, Y; Yoshida, K

    1994-11-01

    We devised a new method (the dorayaki method) using marine agar under in situ pressures to isolate barophilic bacteria from the intestinal contents of three deep-sea fishes (two Coryphaenoides yaquinae samples and one Ilyophis sp. sample) retrieved from depths of 4,700 to 6,100 m in the Northwest Pacific Ocean. All 10 strains isolated from one sample (C. yaquinae) were obligately barophilic. One of the 10 strains did not grow at atmospheric pressure and 103.4 MPa but did grow well between 20.7 and 82.7 MPa, with optimal growth at 41.4 MPa. This method is useful for isolating psychrophilic and barophilic deep-sea bacteria. PMID:16349450

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

    International Nuclear Information System (INIS)

    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

  14. 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.

  15. 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

  16. 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.

  17. A new method for retrieving land surface temperature from HJ-1B data and the temporal influences

    International Nuclear Information System (INIS)

    According to radiation transfer equation (RTE), it is an ill-conditioned problem to obtain land surface temperature (LST) accurately from the HJ-1B thermal infrared channel. Several algorithms have been proposed to resolve this problem. However, some accurate inputs (e.g. atmospheric parameters and land surface emissivity) always inaccessible to common users are indispensable to their applications. An innovative approach (named MTSC method) based on multi-temporal data was described in this paper, by means of which the LSTs are able to be estimated readily and directly from the radiometrically corrected thermal images, even without any other accurate information. To demonstrate its capability, four HJ-1B images (acquired on Nov 28, Dec 10, Dec 18 and Dec 22, 2011, respectively) mainly covering the Pearl River Delta region were selected for LSTs estimation. The LSTs retrieved by the MTSC method were then compared with the near time MODIS surface temperature products, and the samples were collected through a proper procedure. The preliminary assessments demonstrated that accurate results were obtained by using this new method. For example, for the retrieved results of Dec 22, the systematic errors for land cover and sea area were approximate to 1K and 0.5K, respectively. Further comparisons show that the temporal influence was negligible in this experiment, mainly because of the moderate impacts arisen from the atmospheric variation on the surface thermal property, which was acceptable for the MTSC method. However, modifications and improvements are still necessary to enable the full usage of this new approach

  18. 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.

  19. DOAS tomography for the retrieval of trace gas profiles from satellite-based UV-Vis limb spectra

    Institute of Scientific and Technical Information of China (English)

    Zijun Wang; Shengbo Chen; Chunyan Yang; Mingchang Wang

    2011-01-01

    A new method is employed for retrieving the profiles of trace gas number densities from satellite-based ultraviolet-visible (UV-Vis) spectra of scattered sunlight, which are recorded from the limb atmosphere over a range of tangent heights. The slant column abundances of trace gas along the lines of sight (LOSs)are obtained by differential optical absorption spectroscopy (DOAS), and the tomographic technique is applied to such column abundances to retrieve two-dimensional (2D) concentration profiles. For validation of the tomographic technique, the slant column abundances are simulated by a tested 2D NO2 profile set with latitudes from 90°S to 90°N between altitudes of 0 and 100 km, and the retrieval of number density profiles on 1-km grids is performed. The results suggest that between ±80°, the retrieved structure is almost the same as the test data. According to the comparison of the selected cross sections of the vertical profiles between retrieved and true concentrations, the NO2 number densities have been retrieved with an accuracy of 15% or better and 5% for altitudes between 25 and 40 km. The validation of the retrieved data shows good agreement between the retrieved and true profiles.%@@ A new method is employed for retrieving the profiles of trace gas number densities from satellite-based ultraviolet-visible (UV-Vis) spectra of scattered sunlight, which are recorded from the limb atmosphere over a range of tangent heights. The slant column abundances of trace gas along the lines of sight (LOSs) are obtained by differential optical absorption spectroscopy (DOAS), and the tomographic technique is applied to such column abundances to retrieve two-dimensional (2D) concentration profiles. For validation of the tomographic technique, the slant column abundances are simulated by a tested 2D NO2 profile set with latitudes from 90 °S to 90 ° N between altitudes of 0 and 100 km, and the retrieval of number density profiles on 1-km grids is performed. The

  20. 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.

  1. 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.

  2. [Method of traditional Chinese medicine formula design based on 3D-database pharmacophore search and patent retrieval].

    Science.gov (United States)

    He, Yu-su; Sun, Zhi-yi; Zhang, Yan-ling

    2014-11-01

    By using the pharmacophore model of mineralocorticoid receptor antagonists as a starting point, the experiment stud- ies the method of traditional Chinese medicine formula design for anti-hypertensive. Pharmacophore models were generated by 3D-QSAR pharmacophore (Hypogen) program of the DS3.5, based on the training set composed of 33 mineralocorticoid receptor antagonists. The best pharmacophore model consisted of two Hydrogen-bond acceptors, three Hydrophobic and four excluded volumes. Its correlation coefficient of training set and test set, N, and CAI value were 0.9534, 0.6748, 2.878, and 1.119. According to the database screening, 1700 active compounds from 86 source plant were obtained. Because of lacking of available anti-hypertensive medi cation strategy in traditional theory, this article takes advantage of patent retrieval in world traditional medicine patent database, in order to design drug formula. Finally, two formulae was obtained for antihypertensive. PMID:25850277

  3. An automatic Planetary Boundary Layer height retrieval method with compact EZ backscattering Lidar in the frame of ICOS campaign

    Science.gov (United States)

    Loaec, S.; Lolli, S.; Sauvage, L.; Boquet, M.; Xueref-Remy, I.

    2009-12-01

    Bigger strongly urbanized cities in the world are often exposed to atmospheric pollution events. To understand the chemical and physical processes that are taking place in these areas it is necessary to describe correctly the Planetary Boundary Layer (PBL) dynamics and the PBL height evolution. For these proposals, a compact and rugged eye safe UV Lidar, the EZLIDAR™, was developed together by CEA/LMD and LEOSPHERE (France) to study and investigate structural and optical properties of clouds and aerosols and PBL time evolution. EZLIDAR™ has been validated by different remote and in-situ instruments as MPL Type-4 Lidar manufactured by NASA at ARM/SGP site or the LNA (Lidar Nuage Aerosol) at the Laboratoire de Metereologie Dynamique LMD (France) and during several intercomparison campaigns. EZLIDAR™ algorithm retrieves automatically the PBL height in real-time. The method is based on the detection of the slope of the signal linked to a sharp change in concentration of the aerosols. Once detected, the different layers are filtered on a 15mn sample and classified between nocturnal, convective or residual layer, depending on the time and date. This method has been validated against those retrieved by the algorithm STRAT from data acquired at IPSL, France, showing 95% of correlation. In this paper are presented the results of the intercomparison campaign that took place in Orleans, France and Mace Head, Ireland in the framework of ICOS (Integrated Carbon Observation System) project, where the EZ Lidar™ worked under all weather conditions, clear sky, fog, low clouds, during the whole month of October 2008. Moreover, thanks to its 3D scanning capability, the EZLIDAR was able to provide the variability of the PBL height around the site, enabling the scientists to estimate the flux intensities that play a key role in the radiative transfer budget and in the atmospheric pollutants dispersion.

  4. 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.

  5. Feasibility analysis of organic Tea authentication using 15N natural abundance method

    International Nuclear Information System (INIS)

    Organic agricultural products were always adulterated by pollutant-free agricultural products in market because of lacking of available authentication technique. Organic tea was one of the largest organic agricultural products in China which are facing the same problem and can not be accepted by consumers. In this paper, based on the newest information of δ 15N from soil-plant-fertilizer system, a new method was suggested to identify whether N fertilizer was applied to organic tea in producing processing. Meanwhile, the principle of this new method and its feasibility were discussed. (authors)

  6. Adsorption and photocatalysis in water treatment:active, abundant and inexpensive materials and methods

    OpenAIRE

    Pirilä, M. (Minna)

    2015-01-01

    Abstract Water contamination is a global problem and the growing utilization of limited water resources creates a need for efficient purification methods. Industrial effluents are polluting the natural waters, e.g. uncontrolled mining activities in developing countries have created numerous environmental hazards and different types of pollutants. This study focuses on novel adsorbents and photocatalytic materials in order to reach the aim of more efficient and affordable water treatment. ...

  7. A Method for Retrieving Daily Land Surface Albedo from Space at 30-m Resolution

    Directory of Open Access Journals (Sweden)

    Bo Gao

    2015-08-01

    Full Text Available Land surface albedo data with high spatio-temporal resolution are increasingly important for scientific studies addressing spatially and/or temporally small-scale phenomena, such as urban heat islands and urban land surface energy balance. Our previous study derived albedo data with 2–4-day and 30-m temporal and spatial resolution that have better spatio-temporal resolution than existing albedo data, but do not completely satisfy the requirements for monitoring high-frequency land surface changes at the small scale. Downscaling technology provides a chance to further improve the albedo data spatio-temporal resolution and accuracy. This paper introduces a method that combines downscaling technology for land surface reflectance with an empirical method of deriving land surface albedo. Firstly, downscaling daily MODIS land surface reflectance data (MOD09GA from 500 m to 30 m on the basis of HJ-1A/B BRDF data with 2–4-day and 30-m temporal and spatial resolution is performed: this is the key step in the improved method. Subsequently, the daily 30-m land surface albedo data are derived by an empirical method combining prior knowledge of the MODIS BRDF product and the downscaled daily 30-m reflectance. Validation of albedo data obtained using the proposed method shows that the new method has both improved spatio-temporal resolution and good accuracy (a total absolute accuracy of 0.022 and a total root mean squared error at six sites of 0.028.

  8. 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.

  9. 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...

  10. 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.

  11. 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.

  12. 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. PMID:27089887

  13. 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.

  14. An Efficient Method for the Retrieval of Objects by Topological Relations in Spatial Database Systems.

    Science.gov (United States)

    Lin, P. L.; Tan, W. H.

    2003-01-01

    Presents a new method to improve the performance of query processing in a spatial database. Experiments demonstrated that performance of database systems can be improved because both the number of objects accessed and number of objects requiring detailed inspection are much less than those in the previous approach. (AEF)

  15. 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

    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...

  16. 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...

  17. 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

  18. Retrieving quasi-phase-matching structure with discrete layer-peeling method

    OpenAIRE

    Zhang, Q. W.; Zeng, Xianglong; Wang, M.; Wang, T Y; Chen, X. F.

    2012-01-01

    An approach to reconstruct a quasi-phase-matching grating by using a discrete layer-peeling algorithm is presented. Experimentally measured output spectra of Solc-type filters, based on uniform and chirped QPM structures, are used in the discrete layer-peeling algorithm. The reconstructed QPM structures are in agreement with the exact structures used in the experiment and the method is verified to be accurate and efficient in quality inspection on quasi-phase-matching grating.

  19. Retrieving quasi-phase-matching structure with discrete layer-peeling method

    DEFF Research Database (Denmark)

    Zhang, Q. W.; Zeng, Xianglong; Wang, M.;

    2012-01-01

    An approach to reconstruct a quasi-phase-matching grating by using a discrete layer-peeling algorithm is presented. Experimentally measured output spectra of Solc-type filters, based on uniform and chirped QPM structures, are used in the discrete layer-peeling algorithm. The reconstructed QPM...... structures are in agreement with the exact structures used in the experiment and the method is verified to be accurate and efficient in quality inspection on quasi-phase-matching grating....

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

    OpenAIRE

    Gielen, C.; Van Roozendael, M.; F. Hendrick; Pinardi, G.; T. Vlemmix; Bock, V.; Backer, H; Fayt, C.; Hermans, C.; Gillotay, D.; Wang, P.

    2014-01-01

    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 a...

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

    OpenAIRE

    Gielen, C.; Van Roozendael, M.; Hendrick, F.; Pinardi, G; T. Vlemmix; V. De Bock; DE BACKER H.; C. Fayt; Hermans, C.; Gillotay, D.; Wang, P.

    2014-01-01

    We present a cloud-screening method based on differential optical absorption spectroscopy (DOAS) measurements, more specifically using intensity measurements 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 ...

  2. 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.

  3. A New Method to Retrieve, Cluster And Annotate Clinical Literature Related To Electronic Health Records

    OpenAIRE

    Fernández, Izaskun; Jiménez Castellanos, Ana; García de Kortázar, Xabier; Pérez del Rey, David

    2011-01-01

    The access to medical literature collections such as PubMed, MedScape or Cochrane has been increased notably in the last years by the web-based tools that provide instant access to the information. However, more sophisticated methodologies are needed to exploit efficiently all that information. The lack of advanced search methods in clinical domain produce that even using well-defined questions for a particular disease, clinicians receive too many results. Since no information analysis is applie...

  4. 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.

  5. Methods for Heel Retrieval for Tanks C-101, C-102, and C-111 at the Hanford Site - 13064

    International Nuclear Information System (INIS)

    The purpose of this paper is to evaluate the prospects of using bulk waste characteristics to determine the most appropriate heel retrieval technology. If the properties of hard to remove heels can be determined before bulk retrieval, then a heel retrieval technology can be selected before bulk retrieval is complete. This would save substantially on sampling costs and would allow the deployment of the heel retrieval technology immediately after bulk retrieval. The latter would also accelerate the heel removal schedule. A number of C-farm retrievals have been fully or partially completed at the time of this writing. Thus, there is already substantial information on the success of different technologies and the composition of the heels. There is also substantial information on the waste types in each tank based on historical records. Therefore, this study will correlate the performance of technologies used so far and compare them to the known waste types in the tanks. This will be used to estimate the performance of future C Farm heel retrievals. An initial decision tree is developed and employed on tanks C-101, C-102, and C 111. An assumption of this study is that no additional characterization information would be available, before or after retrieval. Note that collecting additional information would substantially increase the probability of success. Deploying some in-situ testing technologies, such as a water lance or an in-situ Raman probe, might substantially increase the probability of successfully selecting the process conditions without having to take samples from the tanks for laboratory analysis. (authors)

  6. Methods for heel retrieval for tanks C-101, C-102, and C-111 at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Sams, Terry L. [Washington River Protection Solutions, LLC, Richland, WA (United States); Kirch, N. W. [Washington River Protection Solutions, LLC, Richland, WA (United States); Reynolds, Jacob G. [Washington River Protection Solutions, LLC, Richland, WA (United States)

    2013-01-11

    The purpose of this paper is to evaluate the prospects of using bulk waste characteristics to determine the most appropriate heel retrieval technology. If the properties of hard to remove heels can be determined before bulk retrieval, then a heel retrieval technology can be selected before bulk retrieval is complete. This would save substantially on sampling costs and would allow the deployment of the heel retrieval technology immediately after bulk retrieval. The latter would also accelerate the heel removal schedule. A number of C-farm retrievals have been fully or partially completed at the time of this writing. Thus, there is already substantial information on the success of different technologies and the composition of the heels. There is also substantial information on the waste types in each tank based on historical records. Therefore, this study will correlate the performance of technologies used so far and compare them to the known waste types in the tanks. This will be used to estimate the performance of future C Farm heel retrievals. An initial decision tree is developed and employed on tanks C-101, C-102, and C 111. An assumption of this study is that no additional characterization information would be available, before or after retrieval. Note that collecting additional information would substantially increase the probability of success. Deploying some in-situ testing technologies, such as a water lance or an in-situ Raman probe, might substantially increase the probability of successfully selecting the process conditions without having to take samples from the tanks for laboratory analysis.

  7. Gene-Disease Interaction Retrieval from Multiple Sources: A Network Based Method

    Science.gov (United States)

    Huang, Lan; Wang, Yan

    2016-01-01

    The number of gene-related databases has been growing largely along with the research on genes of bioinformatics. Those databases are filled with various gene functions, pathways, interactions, and so forth, while much biomedical knowledge about human diseases is stored as text in all kinds of literatures. Researchers have developed many methods to extract structured biomedical knowledge. Some study and improve text mining algorithms to achieve efficiency in order to cover as many data sources as possible, while some build open source database to accept individual submissions in order to achieve accuracy. This paper combines both efforts and biomedical ontologies to build an interaction network of multiple biomedical ontologies, which guarantees its robustness as well as its wide coverage of biomedical publications. Upon the network, we accomplish an algorithm which discovers paths between concept pairs and shows potential relations. PMID:27478829

  8. 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.

  9. 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.

  10. PROBLEM-MODEL TRAINING AS A NEW KIND OF PROBLEM RETRIEVAL METHODS OF TEACHING

    OpenAIRE

    Fominyh, M. V.; Фоминых, М. В.

    2014-01-01

    The article refers to the problem of the usage of problem model teaching technologies as a new type of problem-search methods of teaching in modern vocational pedagogical higher school. Cтатья посвящена проблеме использования проблемно-модельного тренинга как нового вида проблемно-поисковых методов обучения в современной педагогике.

  11. 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。

  12. 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.

  13. Markov Chain Method for Radiative Transfer Modeling: A Case Study of Aerosol/Surface Retrieval using AirMSPI Measurements

    Science.gov (United States)

    Xu, F.; Diner, D. J.; Davis, A. B.; Latyshev, S.; Garay, M. J.; Kalashnikova, O.; Ge, C.; Wang, J.

    2013-12-01

    A vector Markov chain (MarCh) radiative transfer (RT) code developed at JPL that includes forward modeling of radiance and polarization fields and linearization (analytical estimation of Jacobians) was incorporated into an aerosol and surface retrieval package for a plane-parallel atmosphere/surface system. The RT computation by MarCh is based on matrix operations. To improve the code's computational efficiency, the forward model is currently undergoing acceleration through the exploration of different strategies for matrix operation and inversion, including numerical optimization, multi-threading/multi-processing techniques on a CPU. Implementation on a graphics processing unit (GPU) is also planned. Following a benchmarking study of the forward model, the performance of MarCh in aerosol and surface retrieval is being tested. With an optimized algorithm, we started from aerosol optical depth and surface retrieval using imagery acquired by Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) over Fresno, CA. Aerosol properties including concentration and size distribution of different species provided by the Weather Research and Forecasting (WRF)-Chem model were used to constrain the retrieval and reduce the parameter space. The assumptions of spectral invariance in the angular shape of surface bidirectional reflectance factors (BRFs) and the magnitude of polarized surface BRFs were tested. The aerosol and surface properties are then relaxed in a stepwise way to refine the aerosol retrieval results and enable comparison with independent retrievals obtained from a collocated AErosol RObotic NETwork (AERONET) station.

  14. A new method for fusion, denoising and enhancement of x-ray images retrieved from Talbot-Lau grating interferometry

    Science.gov (United States)

    Scholkmann, Felix; Revol, Vincent; Kaufmann, Rolf; Baronowski, Heidrun; Kottler, Christian

    2014-03-01

    This paper introduces a new image denoising, fusion and enhancement framework for combining and optimal visualization of x-ray attenuation contrast (AC), differential phase contrast (DPC) and dark-field contrast (DFC) images retrieved from x-ray Talbot-Lau grating interferometry. The new image fusion framework comprises three steps: (i) denoising each input image (AC, DPC and DFC) through adaptive Wiener filtering, (ii) performing a two-step image fusion process based on the shift-invariant wavelet transform, i.e. first fusing the AC with the DPC image and then fusing the resulting image with the DFC image, and finally (iii) enhancing the fused image to obtain a final image using adaptive histogram equalization, adaptive sharpening and contrast optimization. Application examples are presented for two biological objects (a human tooth and a cherry) and the proposed method is compared to two recently published AC/DPC/DFC image processing techniques. In conclusion, the new framework for the processing of AC, DPC and DFC allows the most relevant features of all three images to be combined in one image while reducing the noise and enhancing adaptively the relevant image features. The newly developed framework may be used in technical and medical applications.

  15. A new method for fusion, denoising and enhancement of x-ray images retrieved from Talbot–Lau grating interferometry

    International Nuclear Information System (INIS)

    This paper introduces a new image denoising, fusion and enhancement framework for combining and optimal visualization of x-ray attenuation contrast (AC), differential phase contrast (DPC) and dark-field contrast (DFC) images retrieved from x-ray Talbot–Lau grating interferometry. The new image fusion framework comprises three steps: (i) denoising each input image (AC, DPC and DFC) through adaptive Wiener filtering, (ii) performing a two-step image fusion process based on the shift-invariant wavelet transform, i.e. first fusing the AC with the DPC image and then fusing the resulting image with the DFC image, and finally (iii) enhancing the fused image to obtain a final image using adaptive histogram equalization, adaptive sharpening and contrast optimization. Application examples are presented for two biological objects (a human tooth and a cherry) and the proposed method is compared to two recently published AC/DPC/DFC image processing techniques. In conclusion, the new framework for the processing of AC, DPC and DFC allows the most relevant features of all three images to be combined in one image while reducing the noise and enhancing adaptively the relevant image features. The newly developed framework may be used in technical and medical applications. (paper)

  16. Content Based Video Retrieval Systems

    Directory of Open Access Journals (Sweden)

    B V Patel

    2012-05-01

    Full Text Available With the development of multimedia data types and available bandwidth there is huge demand of video retrieval systems, as users shift from text based retrieval systems to content based retrieval systems. Selection of extracted features play an important role in content based video retrieval regardless of video attributes being under consideration. These features are intended for selecting, indexing and ranking according to their potential interest to the user. Good features selection also allows the time and space costs of the retrieval process to be reduced. This survey reviews the interesting features that can beextracted from video data for indexing and retrieval along with similarity measurement methods. We also identify present research issues in area of content based video retrieval systems.

  17. Estimating wetland vegetation abundance from Landsat-8 operational land imager imagery: a comparison between linear spectral mixture analysis and multinomial logit modeling methods

    Science.gov (United States)

    Zhang, Min; Gong, Zhaoning; Zhao, Wenji; Pu, Ruiliang; Liu, Ke

    2016-01-01

    Mapping vegetation abundance by using remote sensing data is an efficient means for detecting changes of an eco-environment. With Landsat-8 operational land imager (OLI) imagery acquired on July 31, 2013, both linear spectral mixture analysis (LSMA) and multinomial logit model (MNLM) methods were applied to estimate and assess the vegetation abundance in the Wild Duck Lake Wetland in Beijing, China. To improve mapping vegetation abundance and increase the number of endmembers in spectral mixture analysis, normalized difference vegetation index was extracted from OLI imagery along with the seven reflective bands of OLI data for estimating the vegetation abundance. Five endmembers were selected, which include terrestrial plants, aquatic plants, bare soil, high albedo, and low albedo. The vegetation abundance mapping results from Landsat OLI data were finally evaluated by utilizing a WorldView-2 multispectral imagery. Similar spatial patterns of vegetation abundance produced by both fully constrained LSMA algorithm and MNLM methods were observed: higher vegetation abundance levels were distributed in agricultural and riparian areas while lower levels in urban/built-up areas. The experimental results also indicate that the MNLM model outperformed the LSMA algorithm with smaller root mean square error (0.0152 versus 0.0252) and higher coefficient of determination (0.7856 versus 0.7214) as the MNLM model could handle the nonlinear reflection phenomenon better than the LSMA with mixed pixels.

  18. SCI文章的引用情况的检索方法的研究和思考%SCI Article Citation Retrieval Method Research and Thinking

    Institute of Scientific and Technical Information of China (English)

    陈楠楠

    2014-01-01

    目的:研究SCI文章的相应引证文献的检索、查全和查准的最佳方法和途径。途径通过分析在SCIE数据库中的代表性检索案例,阐明了 SCI文章相关的引证文献和总被引频次的检索、确认方法和注意事项。结论使用SCIE数据库的"被引参考文献检索"平台来检索 SCI文章的引证文献和相应的被引频次是最佳途径。%Objective To study the corresponding SCI documents retrieval, recal and check the best approach. Methods By analyzing the representative in the SCIE database retrieval case, the SCI related articles and documents cited frequency search, confirmation method and the mat ers needing at ention. Conclusion The use of SCIE database"cited reference retrieval"platform to retrieve SCI documents and the corresponding citation frequency is the best way.

  19. A differential optical absorption spectroscopy method for retrieval from ground-based Fourier transform spectrometers measurements of the direct solar beam

    Science.gov (United States)

    Huo, Yanfeng; Duan, Minzheng; Tian, Wenshou; Min, Qilong

    2015-08-01

    A differential optical absorption spectroscopy (DOAS)-like algorithm is developed to retrieve the column-averaged dryair mole fraction of carbon dioxide from ground-based hyper-spectral measurements of the direct solar beam. Different to the spectral fitting method, which minimizes the difference between the observed and simulated spectra, the ratios of multiple channel-pairs—one weak and one strong absorption channel—are used to retrieve from measurements of the shortwave infrared (SWIR) band. Based on sensitivity tests, a super channel-pair is carefully selected to reduce the effects of solar lines, water vapor, air temperature, pressure, instrument noise, and frequency shift on retrieval errors. The new algorithm reduces computational cost and the retrievals are less sensitive to temperature and H2O uncertainty than the spectral fitting method. Multi-day Total Carbon Column Observing Network (TCCON) measurements under clear-sky conditions at two sites (Tsukuba and Bremen) are used to derive xxxx for the algorithm evaluation and validation. The DOAS-like results agree very well with those of the TCCON algorithm after correction of an airmass-dependent bias.

  20. Biases associated with several sampling methods used to estimate abundance of Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae).

    Science.gov (United States)

    Schulze, T L; Jordan, R A; Hung, R W

    1997-11-01

    Several tick sampling methods were evaluated for ixodes scapularis Say and Amblyomma americanum (I.) in oak-dominated mixed hard-wood, pitch pine-dominated, and mixed hardwood and pine forests in coastal New Jersey. Walking surveys were more efficient for collecting I. scapularis adults than dragging by a factor of > 2:1. In contrast, drag sampling yielded nearly twice as many A. americanum adults compared with walking surveys. I. scapularis subadults were rarely collected during walking surveys. A. americanum nymphs were collected from drags approximately 3:1 over walking surveys. Twice as many A. americanum larvae were obtained from drags compared with walking surveys. All developmental stages of A. americanum responded positively to carbon dioxide. Pitfall traps and leaf litter samples collected very few ticks. Tick distribution among habitats varied significantly with the sampling method chosen, and the relative ranking of sites with respect to tick abundance varied depending on the stage of tick sampled. Failure to recognize the biases in these commonly used sampling techniques can potentially lead to incorrect conclusions that can have significant adverse public health consequences. PMID:9439115

  1. Abundance analysis of B, A and F dwarfs in the M6 open cluster: Spectrum synthesis method

    Science.gov (United States)

    Kiliçoğlu, T.; Monier, R.; Fossati, L.

    2012-12-01

    The chemical abundances of 10 stars in the M6 open cluster (˜100 Myr) were derived using spectrum synthesis. The stars were observed using the FLAMES/GIRAFFE spectrograph. We found star-to-star variations in abundances for A type stars. General enrichment of Si, Cr, and Y were obtained for the cluster.

  2. 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.

  3. 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

  4. [Testing the energetic equivalence rule for litter ants: effects of different methods for abundance estimates in tropical rainforest].

    Science.gov (United States)

    Vargas, André B; Queiroz, Jarbas M; Mayhé-Nunes, Antônio J; Souza, Guilherme O; Ramos, Elaine F

    2009-01-01

    The Energetic Equivalence Rule (EER) states that species tend to consume energy independent of their body size. Here, the EER was tested for litter ants using body size and abundance data. Rainforest ants were obtained using pitfall traps and Winkler extractor. The abundance data from the Winkler extractions confirmed the EER, while the pitfall traps rejected it. Combination of abundance from pitfall catches and Winkler extractions either confirmed or rejected the EER. Further studies should focus on the interaction between sampling techniques and habitat types in the test of EER for ant communities. PMID:20098936

  5. A novel method to prioritize RNAseq data for post-hoc analysis based on absolute changes in transcript abundance.

    Science.gov (United States)

    McNutt, Patrick; Gut, Ian; Hubbard, Kyle; Beske, Phil

    2015-06-01

    . These findings suggest that the large ΔT genes are not a product of random or stochastic phenomenon, but rather represent biologically meaningful changes in the transcriptional program. They furthermore imply that high abundance transcripts are associated with particularly cellular states, and as cells change in response to internal or external conditions, the relative distribution of the abundant transcripts changes accordingly. Thus, prioritization of DEGs based on the concept of metabolic cost is a simple yet powerful method to identify biologically important transcriptional changes and provide novel insights into cellular behaviors. PMID:25781714

  6. 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.

  7. 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.

  8. 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...

  9. 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。

  10. 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.

  11. 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.

  12. 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...

  13. 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......, and his work on renaissance paintings. On the basic of works of art he develops a theory about ways in which one analyses representational images. Panofsky describes three levels of meaning in a work of art which indicate a difference in presupposed knowledge i.e. nothing (or only practical experience...

  14. Inter-comparison of stratospheric O3 and NO2 abundances retrieved from balloon borne direct sun observations and Envisat/SCIAMACHY limb measurements

    OpenAIRE

    A. Butz; H. Bösch; Camy-Peyret, C.; Chipperfield, M.; Dorf, M.; G. Dufour; Grunow, K.; Jeseck, P.; Kühl, S.; Payan, S.; Pepin, I.; Pukite, J.; Rozanov, A.(CPPM, Aix-Marseille Université and CNRS/IN2P3, Marseille, France); Von Savigny, C; Sioris, C.

    2006-01-01

    International audience Stratospheric O3 and NO2 abundances measured by different remote sensing instruments are inter-compared: (1) Line-of-sight absorptions and vertical profiles inferred from solar spectra in the ultra-violet (UV), visible and infrared (IR) wavelength ranges measured by the LPMA/DOAS (Limb Profile Monitor of the Atmosphere/Differential Optical Absorption Spectroscopy) balloon payload during balloon ascent/descent and solar occultation are examined with respect to interna...

  15. 参数弱固定法反演地表温度%Land surface temperature retrieval by weak-fixed-parameter method

    Institute of Scientific and Technical Information of China (English)

    赵红蕊; 杨斌; 阳园燕

    2011-01-01

    A land surface temperature (LST) retrieval algorithm called week-fixed-parameter method was proposed. The new method is achieved by week-fixed sensitive parameters so as to control information flow from MODIS thermal infrared data. Based on the thermal infrared radiative transfer theory, a forward retrieval model was established and 14 parameters were retrieved together. The retrieved parameters included LST, average temperature of atmosphere, six bands' atmospheric transmittances and surface emissivities in mid-infrared(3 -5 μm) and infrared(8 ~ 14. 5 μm). The algorithm was tested with both MODTRAN simulated data and MODIS data. Compared with that of split-window algorithm, MODIS temperature products and ground truth, the RMSE is 0. 57 K, which is better than that of traditional split-window algorithm. The test indicates that the weak-fixed-parameter method is effective to retrieve LST.%提出了弱固定敏感参数、控制信息流向目标参数的地表温度反演方法.从热红外辐射传输机理出发,以MODIS为数据源,构建辐射传输方程,同时反演包括地表温度、大气平均温度、中红外(3~5μm)、远红外(8-14.5 μm)6个波段的大气透过率和发射率共计14个参数.以MODTRAN模拟数据和重庆地区MODIS遥感影像为实验数据,进行参数弱固定法地表温度反演,并与劈窗算法反演结果、MODIS温度数据产品及地表实测数据进行了对比分析.实验表明,参数弱固定法反演地表温度的均方根误差达到0.57 K,精度优于传统的劈窗算法,表明了参数弱固定法反演地表温度的可行性.

  16. 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.

  17. 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.

  18. Research and comparison of remote sensing retrieving water table methods%遥感反演地下水位方法的比较研究

    Institute of Scientific and Technical Information of China (English)

    叶欣; 邓正栋; 关洪军; 吴克宏

    2011-01-01

    本文回顾了国内外利用遥感技术反演地下水位的研究成果,依据地下水与地表参数的作用原理,归纳为四种地下水位反演方法,即分别从土壤水分、地表温度、植被指数和地下水流系统的角度进行地下水位反演.详细论述了各种方法的原理和模型,并从模型反演精度、前提条件和适用范围对四种方法进行比较分析.最后进行了总结和展望,对今后的工作重点和研究方向提出了建议,认为建立多因子反演模型、提高地表参数和地下水位反演精度是今后研究的方向.%This paper reviews the nationaL/international study on remote sensing retrieving water table.According to the principal between groundwater and surface information, it is divided into four kinds of methods, which retrieve water table from soil water content, surface temperature, vegetation index and groundwater flow system respectively. The principal and model of each kind is discussed in detail and is compared with each other upon retrieving precision, precondition and applicable area. To sum up, it is considered that founding multiple parameter models, improving retrieving precision of surface parameter and water table are the key direct of future study.

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

    OpenAIRE

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

    2015-01-01

    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 clon...

  20. Application of the angular position of the visible horizon for atmospheric trace gases retrieval by MAX-DOAS method

    Science.gov (United States)

    Bruchkouski, Ilya; Krasovsky, Alexander; Demin, Victor

    2015-04-01

    Significant impact on the retrieval process of atmospheric trace gases by MAX-DOAS has accuracy of the elevation angle adjustment of the telescope unit. Additional information about the magnitude of the true elevation angles in MAX-DOAS system is very important because a slight change in elevation at angles 0 ° - 5 ° leads to a change in the geometry of the observation that has a strong influence on the measured value (slant column density). For monitoring the state of the atmosphere automated device based on the spectrograph ORIEL MS257 with a cooled CCD Andor Technology, spectral range 411-493 nm, FWHM = 0.5 nm has been constructed. This instrument records the spectrum of scattered sunlight in the range of elevation angles 0 ° - 90 ° within an aperture of 1.3 °. The number of registered spectra per day amounts to 4000. This device passed MAX-DOAS intercomparison campaign in the Max-Planck-Institute for Chemistry (Mainz) for the period 20.06.2013 - 10.09.2013. Procedures of the retrieval of nitrogen dioxide parallel measurements has been performed, the results of comparisons will be presented. Series of data about the angular position of the visible horizon line for two months of observation has been obtained. Using this pattern, corrections can be made in determining the elevation angle of the telescope unit, during the processing of the experimental data by MAX-DOAS.

  1. 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.

  2. Natural Language Information Retrieval: Progress Report.

    Science.gov (United States)

    Perez-Carballo, Jose; Strzalkowski, Tomek

    2000-01-01

    Reports on the progress of the natural language information retrieval project, a joint effort led by GE (General Electric) Research, and its evaluation at the sixth TREC (Text Retrieval Conference). Discusses stream-based information retrieval, which uses alternative methods of document indexing; advanced linguistic streams; weighting; and query…

  3. The information retrieval technology

    OpenAIRE

    Краліна, Ганна Сергіївна; Тупота, Евгеній Вікторович

    2009-01-01

    Information retrieval is the science of searching for documents, for information within documents and for metadata about documents, as well as that of searching relational databases and the World Wide Web. There is overlap in the usage of the terms data retrieval, document retrieval, information retrieval, and text retrieval, but each also has its own body of literature, theory, praxis and technologies

  4. 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.

  5. Image Retrieval Based on Fractal Dictionary Parameters

    OpenAIRE

    Yuanyuan Sun; Rudan Xu; Lina Chen; Xiaopeng Hu

    2013-01-01

    Content-based image retrieval is a branch of computer vision. It is important for efficient management of a visual database. In most cases, image retrieval is based on image compression. In this paper, we use a fractal dictionary to encode images. Based on this technique, we propose a set of statistical indices for efficient image retrieval. Experimental results on a database of 416 texture images indicate that the proposed method provides a competitive retrieval rate, compared to the existi...

  6. Content Base Image Retrieval Using Phong Shading

    OpenAIRE

    Uday Pratap Singh; Sanjeev Jain; Gulfishan Firdose Ahmed

    2010-01-01

    The digital image data is rapidly expanding in quantity and heterogeneity. The traditional information retrieval techniques does not meet the user’s demand, so there is need to develop an efficient system for content based image retrieval. Content based image retrieval means retrieval of images from database on the basis of visual features of image like as color, texture etc. In our proposed method feature are extracted after applying Phong shading on input image. Phong shading, flattering ou...

  7. DISR: Dental Image Segmentation and Retrieval

    OpenAIRE

    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 implemente...

  8. A system for storage of references. A method of storage and retrieval of references on a personal microcomputer.

    Science.gov (United States)

    Alagesan, K; McLeod, G F

    1985-11-01

    A computer program, written in BBC BASIC, for storage and retrieval of literature references on a personal microcomputer fitted with floppy disc drives is described. The storage capacity is 425 references per 100K disc. A versatile search function allows ready access to references by matching any number of combinations of the following 10 items: authors, name, year and volume of journal, pages, reference number, and up to four key words. The resulting bibliographic list can be formatted to any desired house style. There is a facility for sorting the list into alphabetical order of the authors and the use of a wordprocessor for special print styles on any BBC compatible printer. These two features make retyping the list unnecessary. A search can be done manually, while browsing through the references. Advantages of this system over the existing packages are discussed. The program is totally run by on-screen menus, and it is easy to use, even by a novice. PMID:3907401

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. Ontology-based Information Retrieval

    DEFF Research Database (Denmark)

    Styltsvig, Henrik Bulskov

    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......, as well as how to fuse together the ideas of ontological similarity and ontological indexing into a realistic information retrieval scenario. To achieve the recognition of semantic knowledge in a text, shallow natural language processing is used during indexing that reveals knowledge to the level of noun...

  14. Simultaneous retrieval of CO2 and aerosols in a plume from hyper spectral imagery: application to the characterization of forest fire smoke using AVIRIS data

    International Nuclear Information System (INIS)

    Hyper spectral imagery is a widely used technique to study atmospheric composition. For several years, many methods have been developed to estimate the abundance of gases. However, existing methods do not simultaneously retrieve the properties of aerosols and often use standard aerosol models to describe the radiative impact of particles. This approach is not suited to the characterization of plumes, because plume particles may have a very different composition and size distribution from aerosols described by the standard models given by radiative transfer codes. This article presents a new method to simultaneously retrieve carbon dioxide (CO2) and aerosols inside a plume, combining an aerosol retrieval algorithm using visible and near-infrared (VNIR) wavelengths and a CO2 estimation algorithm using shortwave infrared (SWIR) wavelengths. The micro-physical properties of the plume particles, obtained after aerosol retrieval, are used to calculate their optical properties in the SWIR. Then, a database of atmospheric terms is generated with the radiative transfer code, Moderate Resolution Atmospheric Transmission (MODTRAN). Finally, pixel radiances around the 2.0 μm absorption feature are used to retrieve the CO2 abundances. After conducting a signal sensitivity analysis, the method was applied to two airborne visible/infrared imaging spectrometer (AVIRIS) images acquired over areas of biomass burning. For the first image, in situ measurements were available. The results show that including the aerosol retrieval step before the CO2 estimation: (1) induces a better agreement between in situ measurements and retrieved CO2 abundances (the CO2 overestimation of about 15%, induced by neglecting aerosols has been corrected, especially for pixels where the plume is not very thick); (2) reduces the standard deviation of estimated CO2 abundance by a factor of four; and (3) causes the spatial distribution of retrieved concentrations to be coherent. (authors)

  15. 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.

  16. 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.

  17. Context based multimedia information retrieval

    OpenAIRE

    Mølgaard, Lasse Lohilahti; Hansen, Lars Kai; Larsen, Jan

    2009-01-01

    The large amounts of digital media becoming available require that new approaches are developed for retrieving, navigating and recommending the data to users in a way that refl ects how we semantically perceive the content. The thesis investigates ways to retrieve and present content for users with the help of contextual knowledge. Our approach to model the context of multimedia is based on unsupervised methods to automatically extract meaning. We investigate two paths of context modelling. T...

  18. 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

  19. A SYSTEMATIC RETRIEVAL ANALYSIS OF SECONDARY ECLIPSE SPECTRA. I. A COMPARISON OF ATMOSPHERIC RETRIEVAL TECHNIQUES

    Energy Technology Data Exchange (ETDEWEB)

    Line, Michael R.; Wolf, Aaron S.; Zhang, Xi; Knutson, Heather; Kammer, Joshua A.; Yung, Yuk L. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Ellison, Elias [Flintridge Preparatory School, La Cañada, CA 91011 (United States); Deroo, Pieter; Crisp, Dave, E-mail: mrl@gps.caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099 (United States)

    2013-10-01

    Exoplanet atmosphere spectroscopy enables us to improve our understanding of exoplanets 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 molecular abundances allowed by the data, which is often difficult given the low information content of most exoplanet spectra that commonly leads to degeneracies in the interpretation. A variety of spectral retrieval approaches have been applied to exoplanet spectra, but no previous investigations have sought to compare these approaches. We compare three different retrieval methods: optimal estimation, differential evolution Markov chain Monte Carlo, and bootstrap Monte Carlo on a synthetic water-dominated hot Jupiter. We discuss expectations of uncertainties in abundances and temperatures given current and potential future observations. In general, we find that the three approaches agree for high spectral resolution, high signal-to-noise data expected to come from potential future spaceborne missions, but disagree for low-resolution, low signal-to-noise spectra representative of current observations. We also compare the results from a parameterized temperature profile versus a full classical Level-by-Level approach and discriminate in which situations each of these approaches is applicable. Furthermore, we discuss the implications of our models for the inferred C-to-O ratios of exoplanetary atmospheres. Specifically, we show that in the observational limit of a few photometric points, the retrieved C/O is biased toward values near solar and near one simply due to the assumption of uninformative priors.

  20. 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.

  1. Practical Bias Correction in Aerial Surveys of Large Mammals: Validation of Hybrid Double-Observer with Sightability Method against Known Abundance of Feral Horse (Equus caballus) Populations

    Science.gov (United States)

    2016-01-01

    Reliably estimating wildlife abundance is fundamental to effective management. Aerial surveys are one of the only spatially robust tools for estimating large mammal populations, but statistical sampling methods are required to address detection biases that affect accuracy and precision of the estimates. Although various methods for correcting aerial survey bias are employed on large mammal species around the world, these have rarely been rigorously validated. Several populations of feral horses (Equus caballus) in the western United States have been intensively studied, resulting in identification of all unique individuals. This provided a rare opportunity to test aerial survey bias correction on populations of known abundance. We hypothesized that a hybrid method combining simultaneous double-observer and sightability bias correction techniques would accurately estimate abundance. We validated this integrated technique on populations of known size and also on a pair of surveys before and after a known number was removed. Our analysis identified several covariates across the surveys that explained and corrected biases in the estimates. All six tests on known populations produced estimates with deviations from the known value ranging from -8.5% to +13.7% and <0.7 standard errors. Precision varied widely, from 6.1% CV to 25.0% CV. In contrast, the pair of surveys conducted around a known management removal produced an estimated change in population between the surveys that was significantly larger than the known reduction. Although the deviation between was only 9.1%, the precision estimate (CV = 1.6%) may have been artificially low. It was apparent that use of a helicopter in those surveys perturbed the horses, introducing detection error and heterogeneity in a manner that could not be corrected by our statistical models. Our results validate the hybrid method, highlight its potentially broad applicability, identify some limitations, and provide insight and guidance

  2. Deep-sequencing method for quantifying background abundances of symbiodinium types: exploring the rare symbiodinium biosphere in reef-building corals.

    Directory of Open Access Journals (Sweden)

    Kate M Quigley

    Full Text Available The capacity of reef-building corals to associate with environmentally-appropriate types of endosymbionts from the dinoflagellate genus Symbiodinium contributes significantly to their success at local scales. Additionally, some corals are able to acclimatize to environmental perturbations by shuffling the relative proportions of different Symbiodinium types hosted. Understanding the dynamics of these symbioses requires a sensitive and quantitative method of Symbiodinium genotyping. Electrophoresis methods, still widely utilized for this purpose, are predominantly qualitative and cannot guarantee detection of a background type below 10% of the total Symbiodinium population. Here, the relative abundances of four Symbiodinium types (A13, C1, C3, and D1 in mixed samples of known composition were quantified using deep sequencing of the internal transcribed spacer of the ribosomal RNA gene (ITS-2 by means of Next Generation Sequencing (NGS using Roche 454. In samples dominated by each of the four Symbiodinium types tested, background levels of the other three types were detected when present at 5%, 1%, and 0.1% levels, and their relative abundances were quantified with high (A13, C1, D1 to variable (C3 accuracy. The potential of this deep sequencing method for resolving fine-scale genetic diversity within a symbiont type was further demonstrated in a natural symbiosis using ITS-1, and uncovered reef-specific differences in the composition of Symbiodinium microadriaticum in two species of acroporid corals (Acropora digitifera and A. hyacinthus from Palau. The ability of deep sequencing of the ITS locus (1 and 2 to detect and quantify low-abundant Symbiodinium types, as well as finer-scale diversity below the type level, will enable more robust quantification of local genetic diversity in Symbiodinium populations. This method will help to elucidate the role that background types have in maximizing coral fitness across diverse environments and in

  3. 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...

  4. The MOSDEF Survey: Detection of [O III]λ4363 and the Direct-method Oxygen Abundance of a Star-forming Galaxy at z = 3.08

    Science.gov (United States)

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

    2016-07-01

    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 [O iii]λ4363 has been detected and the first time that this line has been measured at z\\gt 2. We estimate an oxygen abundance of 12+{log}({{O}}/{{H}})={8.00}-0.14+0.13. This galaxy is a low-mass ({10}9.3 {M}ȯ ), highly star-forming (∼50 {M}ȯ yr‑1) system that hosts a young stellar population (∼160 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)}{{gas}}\\lt 0.14), and a high electron density ({n}e∼ 500 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 [O iii]λ4363 measurements and show that galaxies at z∼ 1{--}3 follow the same strong-line correlations as galaxies in the local universe. This agreement suggests that the relationship between ionization parameter and O/H is similar for z∼ 0 and high-redshift galaxies. These results imply that metallicity calibrations based on lines of oxygen, neon, and hydrogen do not strongly evolve with redshift and can reliably estimate abundances out to z∼ 3, paving the way for robust measurements of the evolution of the mass–metallicity relation to high redshift. Based on data obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W.M. Keck Foundation.

  5. 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

  6. Ontology-based Information Retrieval

    DEFF Research Database (Denmark)

    Styltsvig, Henrik Bulskov

    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......, as well as how to fuse together the ideas of ontological similarity and ontological indexing into a realistic information retrieval scenario. To achieve the recognition of semantic knowledge in a text, shallow natural language processing is used during indexing that reveals knowledge to the level of noun...

  7. An evaluation method of the neutron fluence and spectrum by measuring the change of isotopic abundance ratios of arbitrary pairs of nuclides on heavy irradiation

    International Nuclear Information System (INIS)

    An evaluation method of the neutron fluence and mean spectrum with which samples have been irradiated is proposed. The principle is based on measuring the change of the isotopic abundance ratios of arbitrary pairs of nuclides having different neutron absorption cross sections for both thermal and intermediate neutrons. Advantages of the method are as follows, although sensitivity is lower than that of the ordinary activation method in a short irradiation period. i) Any sample can be used irrespective of irradiation history. ii) Nuclides present as impurities in samples can be used as detectors. iii) Neutron fluences and mean spectra with which samples have been heavily irradiated can be measured with reasonable accuracy, thus making it possible to offer the direct information to radiation damage studies. The present study deals with the principle and applicability of the method. (author)

  8. 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.

  9. Determination of plutonium isotopic abundances by gamma-ray spectrometry. Interim report on the status of methods and techniques developed by the Lawrence Livermore Laboratory

    International Nuclear Information System (INIS)

    This report presents an overview of methods and techniques developed by the Lawrence Livermore Laboratory for determining plutonium isotopic abundances from gamma-ray spectra that have been measured with germanium detectors. The methodology of fitting the spectral features includes discussions of algorithms for gamma-ray and x-ray peak shape fitting and generation of response spectra profiles characteristic of specific isotopes. Applications of the techniques developed at government, commercial, and Japanese reprocessing plants are described. Current development of the methodology for the nondestructive analysis of samples containing nondescript solid materials is also presented

  10. 基于 LDA 模型的 Ad hoc 信息检索方法研究%Ad hoc information retrieval method based on LDA

    Institute of Scientific and Technical Information of China (English)

    卜质琼; 郑波尽

    2015-01-01

    传统的话题模型假设每个文档只属于一个话题,而实际情况下一个文档往往与多个话题相关。应用LDA 模型将文档表示为多个话题的组合,并基于语言模型框架,提出了一种基于 LDA 的混合模型用于文本信息的 Ad hoc 检索。该方法将 LDA 模型与文档模型相结合,与聚类模型相比,在保持较低的计算复杂度外,具有很高的检索性能,因此更适用于大规模文档集的信息检索。%Traditional topic model assumes that each document is related only one topic,but in practice,a document is usual-ly related with multi topics.This paper represented a document with combination of multi topics with the LDA model,and pro-posed a LDA based mixture model for Ad hoc information retrieval method in language model framework.The proposed method combined the LDA and the document model.Compared with cluster-based model,it has a higher performance,while keeping low computation complexity,and thus can be used in information retrieval of large scale document collections.

  11. Algorithm improvement toward better retrieval of CO2 and CH4 profiles from GOSAT/TANSO-FTS thermal infrared spectra

    Science.gov (United States)

    Saitoh, N.; Imasu, R.; Sugita, T.; Hayashida, S.; Shiomi, K.

    2012-12-01

    The Thermal and Near-infrared Sensor for Carbon Observation Fourier Transform Spectrometer (TANSO-FTS) on board the Greenhouse Gases Observing Satellite (GOSAT) simultaneously observes column abundances and profiles of CO2 and CH4 in the same field of view, from the shortwave infrared (SWIR) and thermal infrared (TIR) bands, respectively. Combined use of the column abundances and profiles above the free troposphere is useful for deriving detailed information on concentrations in the boundary layer, and could provide a good constraint for inverse models. At this time, the version 00.01 (V00.01) data of the TIR L2 standard CO2 and CH4 products have been released to the public. The algorithm of the V00.01 TIR L2 products adopts a non-linear maximum a posteriori (MAP) method with linear mapping. In the V00.01 retrieval, our retrieval target was CO2 or CH4 profile only; temperature and water vapor profiles were taken from the Japan Meteorological Agency Grid Point Values (JMA-GPV) and treated as model parameters, and therefore, their uncertainties could affect the accuracy of the CO2 and CH4 retrieval. In this study, we used more accurate temperature and water vapor profiles observed with GPS radio occultation measurements to retrieve CO2 and CH4 profiles from TIR spectra, and assessed the impact of uncertainties in temperature and water vapor profiles on the TIR retrieval. We also tested simultaneous retrieval including a target gas (CO2 or CH4), contaminating gases such as H2O and N2O, and temperature information. Our preliminary retrieval results showed the simultaneous retrieval could produce better results than the single-target retrieval in some cases.

  12. 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

  13. Distribution and abundance of surface water microlitter in the Baltic Sea: A comparison of two sampling methods.

    Science.gov (United States)

    Setälä, Outi; Magnusson, Kerstin; Lehtiniemi, Maiju; Norén, Fredrik

    2016-09-15

    Two methods for marine microlitter sampling were compared in the Gulf of Finland, northern Baltic Sea: manta trawl (333μm) and a submersible pump (300 or 100μm). Concentrations of microlitter (microplastics, combustion particles, non-synthetic fibres) in the samples collected with both methods and filter sizes remained <10particlesm(-3). The pump with 100μm filter gave higher microlitter concentrations compared to manta trawl or pump with 300μm filter. Manta sampling covers larger areas, but is potentially subjected to contamination during sample processing and does not give precise volumetric values. Using a submerged pump allows method controls, use of different filter sizes and gives exact volumetric measures. Both devices need relatively calm weather for operation. The choice of the method in general depends on the aim of the study. For monitoring environmentally relevant size fractions of microlitter the use of 100μm or smaller mesh size is recommended for the Baltic Sea. PMID:27339742

  14. Application of Markov Chain Monte Carlo Method to Mantle Melting: An Example from REE Abundances in Abyssal Peridotites

    Science.gov (United States)

    LIU, B.; Liang, Y.

    2015-12-01

    Markov chain Monte Carlo (MCMC) simulation is a powerful statistical method in solving inverse problems that arise from a wide range of applications, such as nuclear physics, computational biology, financial engineering, among others. In Earth sciences applications of MCMC are primarily in the field of geophysics [1]. The purpose of this study is to introduce MCMC to geochemical inverse problems related to trace element fractionation during concurrent melting, melt transport and melt-rock reaction in the mantle. MCMC method has several advantages over linearized least squares methods in inverting trace element patterns in basalts and mantle rocks. First, MCMC can handle equations that have no explicit analytical solutions which are required by linearized least squares methods for gradient calculation. Second, MCMC converges to global minimum while linearized least squares methods may be stuck at a local minimum or converge slowly due to nonlinearity. Furthermore, MCMC can provide insight into uncertainties of model parameters with non-normal trade-off. We use MCMC to invert for extent of melting, amount of trapped melt, and extent of chemical disequilibrium between the melt and residual solid from REE data in abyssal peridotites from Central Indian Ridge and Mid-Atlantic Ridge. In the first step, we conduct forward calculation of REE evolution with melting models in a reasonable model space. We then build up a chain of melting models according to Metropolis-Hastings algorithm to represent the probability of specific model. We show that chemical disequilibrium is likely to play an important role in fractionating LREE in residual peridotites. In the future, MCMC will be applied to more realistic but also more complicated melting models in which partition coefficients, diffusion coefficients, as well as melting and melt suction rates vary as functions of temperature, pressure and mineral compositions. [1]. Sambridge & Mosegarrd [2002] Rev. Geophys.

  15. A new method to retrieve the aerosol layer absorption coefficient from airborne flux density and actinic radiation measurements

    OpenAIRE

    Bierwirth, Eike; Wendisch, Manfred; Jäkel, Evelyn; Ehrlich, André; Schmidt, K. Sebastian; Stark, Harald; Pilewskie, Peter; Esselborn, Michael; Gobbi, Gian Paolo; Ferrare, Richard; Müller, Thomas; Clarke, Antony

    2010-01-01

    A new method is presented to derive the mean value of the spectral absorption coefficient of an aerosol layer from combined airborne measurements of spectral net irradiance and actinic flux density. While the method is based on a theoretical relationship of radiative transfer theory, it is applied to atmospheric radiation measurements for the first time. The data have been collected with the Spectral Modular Airborne Radiation Measurement System (SMART‐Albedometer), the Solar Spectral Fl...

  16. 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.

  17. 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...

  18. 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.

  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. SOURCE CODE RETRIEVAL USING SEQUENCE BASED SIMILARITY

    Directory of Open Access Journals (Sweden)

    Yoshihisa Udagawa

    2013-07-01

    Full Text Available Duplicate code adversely affects the quality of software systems and hence should be detected. We discuss an approach that improves source code retrieval using structural information of source code. A lexical parser is developed to extract control statements and method identifiers from Java programs. We propose a similarity measure that is defined by the ratio of the number of sequential fully matching statements to the number of sequential partially matching statements. The defined similarity measure is an extension of the set-based Sorensen-Dice similarity index. This research primarily contributes to the development of a similarity retrieval algorithm that derives meaningful search conditions from a given sequence, and then performs retrieval using all derived conditions. Experiments show that our retrieval model shows an improvement of up to 90.9% over other retrieval models relative to the number of retrieved methods.

  1. Source Code Retrieval Using Sequence Based Similarity

    Directory of Open Access Journals (Sweden)

    Yoshihisa Udagawa

    2013-07-01

    Full Text Available Duplicate code adversely affects the quality of software systems and hence should be detected. We discussan approach that improves source code retrieval using structural information of source code. A lexicalparser is developed to extract control statements and method identifiers from Java programs. We propose asimilarity measure that is defined by the ratio ofthe number of sequential fully matching statementsto thenumber of sequential partially matching statements.The defined similarity measure is an extension oftheset-based Sorensen-Dice similarity index. This research primarily contributes to the development of asimilarity retrieval algorithm that derives meaningful search conditions from a given sequence, and thenperforms retrieval using all derived conditions. Experiments show that our retrieval model shows animprovement of up to 90.9% over other retrieval models relative to the number of retrieved methods.

  2. 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.

  3. 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.

  4. 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.

  5. Method of in situ retrieval of contaminants or other substances using a barrier system and leaching solutions

    Science.gov (United States)

    Nickelson, Reva A.; Walsh, Stephanie; Richardson, John G.; Dick, John R.; Sloan, Paul A.

    2006-12-26

    Processes and methods relating to treating contaminants and collecting desired substances from a zone of interest using subterranean collection and containment barriers. Tubular casings having interlock structures are used to create subterranean barriers for containing and treating buried waste and its effluents. The subterranean barrier includes an effluent collection system. Treatment solutions provided to the zone of interest pass therethrough and are collected by the barrier and treated or recovered, allowing on-site remediation. Barrier components may be used to in the treatment by collecting or removing contaminants or other materials from the zone of interest.

  6. 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.

  7. 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。

  8. 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.

  9. 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.

  10. 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.

  11. A shape-based statistical method to retrieve 2D TRUS-MR slice correspondence for prostate biopsy

    Science.gov (United States)

    Mitra, Jhimli; Srikantha, Abhilash; Sidibé, Désiré; Martí, Robert; Oliver, Arnau; Lladó, Xavier; Ghose, Soumya; Vilanova, Joan C.; Comet, Josep; Meriaudeau, Fabrice

    2012-02-01

    This paper presents a method based on shape-context and statistical measures to match interventional 2D Trans Rectal Ultrasound (TRUS) slice during prostate biopsy to a 2D Magnetic Resonance (MR) slice of a pre-acquired prostate volume. Accurate biopsy tissue sampling requires translation of the MR slice information on the TRUS guided biopsy slice. However, this translation or fusion requires the knowledge of the spatial position of the TRUS slice and this is only possible with the use of an electro-magnetic (EM) tracker attached to the TRUS probe. Since, the use of EM tracker is not common in clinical practice and 3D TRUS is not used during biopsy, we propose to perform an analysis based on shape and information theory to reach close enough to the actual MR slice as validated by experts. The Bhattacharyya distance is used to find point correspondences between shape-context representations of the prostate contours. Thereafter, Chi-square distance is used to find out those MR slices where the prostates closely match with that of the TRUS slice. Normalized Mutual Information (NMI) values of the TRUS slice with each of the axial MR slices are computed after rigid alignment and consecutively a strategic elimination based on a set of rules between the Chi-square distances and the NMI leads to the required MR slice. We validated our method for TRUS axial slices of 15 patients, of which 11 results matched at least one experts validation and the remaining 4 are at most one slice away from the expert validations.

  12. 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.

  13. Applying GA for Optimizing the User Query in Image and Video Retrieval

    OpenAIRE

    Ehsan Lotfi

    2014-01-01

    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 met...

  14. 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.

  15. Glyoxal retrieval from the Ozone Monitoring Instrument

    Directory of Open Access Journals (Sweden)

    C. C. Miller

    2014-06-01

    Full Text Available We present an algorithm for the retrieval of glyoxal from backscattered solar radiation, and apply it to spectra measured by the Ozone Monitoring Instrument (OMI. The algorithm is based on direct spectrum fitting, and adopts a two-step fitting routine to account for liquid water absorption. Previous studies have shown that glyoxal retrieval algorithms are highly sensitive to the position of the spectral fit window. This dependence was systematically tested on real and simulated OMI spectra. We find that a combination of errors resulting from uncertainties in reference cross sections and spectral features associated with the Ring effect are consistent with the fit-window dependence observed in real spectra. This implies an optimal fitting window of 435–461 nm, consistent with previous satellite glyoxal retrievals. The results from the retrieval of simulated spectra also support previous findings that have suggested that glyoxal is sensitive to NO2 cross section temperature. The retrieval window limits of the liquid water retrieval are also tested. A retrieval window 385–470 nm reduces interference with strong spectral features associated with sand. We show that cross track dependent offsets (stripes present in OMI can be corrected using offsets derived from retrieved slant columns over the Sahara, and apply the correction to OMI data. Average glyoxal columns are on average lower than those of previous studies likely owing to the choice of reference sector for offset correction. OMI VCDs are lower compared to other satellites over the tropics and Asia during the monsoon season, suggesting that the new retrieval is less sensitive to water vapor abundance. Consequently we do not see significant glyoxal enhancements over tropical oceans. OMI derived glyoxal-to-formaldehyde ratios over biogenic and anthropogenic source regions are consistent with surface observations.

  16. Glyoxal retrieval from the Ozone Monitoring Instrument

    Directory of Open Access Journals (Sweden)

    C. Chan Miller

    2014-11-01

    Full Text Available We present an algorithm for the retrieval of glyoxal from backscattered solar radiation, and apply it to spectra measured by the Ozone Monitoring Instrument (OMI. The algorithm is based on direct spectrum fitting, and adopts a two-step fitting routine to account for liquid water absorption. Previous studies have shown that glyoxal retrieval algorithms are highly sensitive to the position of the spectral fit window. This dependence was systematically tested on real and simulated OMI spectra. We find that a combination of errors resulting from uncertainties in reference cross sections and spectral features associated with the Ring effect are consistent with the fit-window dependence observed in real spectra. This implies an optimal fitting window of 435–461 nm, consistent with previous satellite glyoxal retrievals. The results from the retrieval of simulated spectra also support previous findings that have suggested that glyoxal is sensitive to NO2 cross-section temperature. The retrieval window limits of the liquid water retrieval are also tested. A retrieval window 385–470 nm reduces interference with strong spectral features associated with sand. We show that cross-track dependent offsets (stripes present in OMI can be corrected using offsets derived from retrieved slant columns over the Sahara, and apply the correction to OMI data. Average glyoxal columns are on average lower than those of previous studies likely owing to the choice of reference sector for offset correction. OMI VCDs (vertical column densitiesare lower compared to other satellites over the tropics and Asia during the monsoon season, suggesting that the new retrieval is less sensitive to water vapour abundance. Consequently we do not see significant glyoxal enhancements over tropical oceans. OMI-derived glyoxal-to-formaldehyde ratios over biogenic and anthropogenic source regions are consistent with surface observations.

  17. 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…

  18. 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.

  19. 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…

  20. Efficient adaptive retrieval and mining in large multimedia databases

    DEFF Research Database (Denmark)

    Assent, Ira

    2009-01-01

    . 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...

  1. Efficient adaptive retrieval and mining in large multimedia databases

    DEFF Research Database (Denmark)

    Assent, Ira

    . 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...

  2. 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

  3. 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.

  4. Gaia FGK benchmark stars: abundances of α and iron-peak elements

    Science.gov (United States)

    Jofré, P.; Heiter, U.; Soubiran, C.; Blanco-Cuaresma, S.; Masseron, T.; Nordlander, T.; Chemin, L.; Worley, C. C.; Van Eck, S.; Hourihane, A.; Gilmore, G.; Adibekyan, V.; Bergemann, M.; Cantat-Gaudin, T.; Delgado-Mena, E.; González Hernández, J. I.; Guiglion, G.; Lardo, C.; de Laverny, P.; Lind, K.; Magrini, L.; Mikolaitis, S.; Montes, D.; Pancino, E.; Recio-Blanco, A.; Sordo, R.; Sousa, S.; Tabernero, H. M.; Vallenari, A.

    2015-10-01

    Context. In the current era of large spectroscopic surveys of the Milky Way, reference stars for calibrating astrophysical parameters and chemical abundances are of paramount importance. Aims: We determine elemental abundances of Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni for our predefined set of Gaia FGK benchmark stars. Methods: By analysing high-resolution spectra with a high signal-to-noise ratio taken from several archive datasets, we combined results of eight different methods to determine abundances on a line-by-line basis. We performed a detailed homogeneous analysis of the systematic uncertainties, such as differential versus absolute abundance analysis. We also assessed errors that are due to non-local thermal equilibrium and the stellar parameters in our final abundances. Results: Our results are provided by listing final abundances and the different sources of uncertainties, as well as line-by-line and method-by-method abundances. Conclusions: The atmospheric parameters of the Gaia FGK benchmark stars are already being widely used for calibration of several pipelines that are applied to different surveys. With the added reference abundances of ten elements, this set is very suitable for calibrating the chemical abundances obtained by these pipelines. Based on NARVAL and HARPS data obtained within the Gaia DPAC (Data Processing and Analysis Consortium) and coordinated by the GBOG (Ground-Based Observations for Gaia) working group and on data retrieved from the ESO-ADP database.Tables C.1-C.35 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/582/A81

  5. Research on the Selection of Patent Retrieval and Analysis methods%专利检索与分析方法的选择研究

    Institute of Scientific and Technical Information of China (English)

    张琪

    2012-01-01

    With the yearly increase in the amount of patent data, it is more and more difficult to get target patent effec-tively , because how to keep the balance between the rate of accuracy and the rate of founding actual patents is always the most challenging part for research. Based on patent data of 3G in DII (Derwent Innovations Index) database, results and differences of traditional theme search and manual code search have been compared. The data analyses close to the actual extent of the situation in two different statistical methods with the same patent data have been done, and the results show that the retrieval and analysis methods used in this paper get more reliable conclusions, which have some practical signifi-cance.%随着专利数量的逐年大幅增长,获取有效目标专利的难度也越来越大,专利检索如何实现检准率和检全率的合理平衡成为研究难点.以德温特专利数据库中3G技术专利为检索对象,比较了传统主题检索和手工代码检索两种方式所对应检索及其分析结果的异同,研究表明选择合理的专利检索和分析方法有助于保证分析结果的权威性.

  6. Aerosol information content analysis of multi-angle high spectral resolution measurements and its benefit for high accuracy greenhouse gas retrievals

    Directory of Open Access Journals (Sweden)

    C. Frankenberg

    2012-07-01

    Full Text Available New generations of space-borne spectrometers for the retrieval of atmospheric abundances of greenhouse gases require unprecedented accuracies as atmospheric variability of long-lived gases is very low. These instruments, such as GOSAT and OCO-2, typically use a high spectral resolution oxygen channel (O2 A-band in addition to CO2 and CH4 channels to discriminate changes in the photon path-length distribution from actual trace gas amount changes. Inaccurate knowledge of the photon path-length distribution, determined by scatterers in the atmosphere, is the prime source of systematic biases in the retrieval. In this paper, we investigate the combined aerosol and greenhouse gas retrieval using multiple satellite viewing angles simultaneously. We find that this method, hitherto only applied in multi-angle imagery such as from POLDER or MISR, greatly enhances the ability to retrieve aerosol properties by 2–3 degrees of freedom. We find that the improved capability to retrieve aerosol parameters significantly reduces interference errors introduced into retrieved CO2 and CH4 total column averages. Instead of focussing solely on improvements in spectral and spatial resolution, signal-to-noise ratios or sampling frequency, multiple angles reduce uncertainty in space based greenhouse gas retrievals more effectively and provide a new potential for dedicated aerosols retrievals.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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. PMID:26353295

  12. 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。

  13. Retrieval of Emotional Memories

    Science.gov (United States)

    Buchanan, Tony W.

    2007-01-01

    Long-term memories are influenced by the emotion experienced during learning as well as by the emotion experienced during memory retrieval. The present article reviews the literature addressing the effects of emotion on retrieval, focusing on the cognitive and neurological mechanisms that have been revealed. The reviewed research suggests that the…

  14. Web Information Retrieval

    OpenAIRE

    Lewandowski, Dirk

    2005-01-01

    Web information retrieval is a research area of its own.While some questions are the same as in „classic“ information retrieval, there are new questions concerning characteristics of the Web,which are discussed. The second part of the article gives an overview of the research literature published within the last two years.

  15. RETRIEVAL EVENTS EVALUATION

    International Nuclear Information System (INIS)

    The purpose of this analysis is to evaluate impacts to the retrieval concept presented in the Design Analysis ''Retrieval Equipment and Strategy'' (Reference 6), from abnormal events based on Design Basis Events (DBE) and Beyond Design Basis Events (BDBE) as defined in two recent analyses: (1) DBE/Scenario Analysis for Preclosure Repository Subsurface Facilities (Reference 4); and (2) Preliminary Preclosure Design Basis Event Calculations for the Monitored Geologic Repository (Reference 5) The objective of this task is to determine what impacts the DBEs and BDBEs have on the equipment developed for retrieval. The analysis lists potential impacts and recommends changes to be analyzed in subsequent design analyses for developed equipment, or recommend where additional equipment may be needed, to allow retrieval to be performed in all DBE or BDBE situations. This analysis supports License Application design and therefore complies with the requirements of Systems Description Document input criteria comparison as presented in Section 7, Conclusions. In addition, the analysis discusses the impacts associated with not using concrete inverts in the emplacement drifts. The ''Retrieval Equipment and Strategy'' analysis was based on a concrete invert configuration in the emplacement drift. The scope of the analysis, as presented in ''Development Plan for Retrieval Events Evaluation'' (Reference 3) includes evaluation and criteria of the following: Impacts to retrieval from the emplacement drift based on DBE/BDBEs, and changes to the invert configuration for the preclosure period. Impacts to retrieval from the main drifts based on DBE/BDBEs for the preclosure period

  16. 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.

  17. 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.

  18. Challenges in Web Information Retrieval

    Science.gov (United States)

    Arora, Monika; Kanjilal, Uma; Varshney, Dinesh

    The major challenge in information access is the rich data available for information retrieval, evolved to provide principle approaches or strategies for searching. The search has become the leading paradigm to find the information on World Wide Web. For building the successful web retrieval search engine model, there are a number of challenges that arise at the different levels where techniques, such as Usenet, support vector machine are employed to have a significant impact. The present investigations explore the number of problems identified its level and related to finding information on web. This paper attempts to examine the issues by applying different methods such as web graph analysis, the retrieval and analysis of newsgroup postings and statistical methods for inferring meaning in text. We also discuss how one can have control over the vast amounts of data on web, by providing the proper address to the problems in innovative ways that can extremely improve on standard. The proposed model thus assists the users in finding the existing formation of data they need. The developed information retrieval model deals with providing access to information available in various modes and media formats and to provide the content is with facilitating users to retrieve relevant and comprehensive information efficiently and effectively as per their requirements. This paper attempts to discuss the parameters factors that are responsible for the efficient searching. These parameters can be distinguished in terms of important and less important based on the inputs that we have. The important parameters can be taken care of for the future extension or development of search engines

  19. Secure content based image retrieval in medical databases

    OpenAIRE

    Bellafqira, Reda; Coatrieux, Gouenou; Bouslimi, Dalel; Quellec, Gwénolé

    2015-01-01

    In this paper, we propose an implementation in the encrypted domain of a content based image retrieval (CBIR) method. It allows a physician to retrieve the most similar images to a query image in an outsourced database while preserving data confidentiality. Image retrieval is based on image signatures we build in the hormomorphically encrypted wavelet transform domain. Experimental results show it is possible to achieve retrieval performance as good as if images were processed nonencrypted.

  20. 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.

  1. Testing the use of a citronella-based repellent as an effective method to reduce the prevalence and abundance of biting flies in avian nests

    OpenAIRE

    Martínez de la Puente, Josué; Merino, Santiago; Lobato, Elisa; Rivero de Aguilar, Juan; Cerro Gómez, Sara del; Ruiz de Castañeda, Rafael

    2009-01-01

    Here, we validate the use of a citronella (natural oil) based repellent to reduce the abundance of flying blood-sucking insects in avian nests. These insects are important parasites of birds affecting them as blood feeders and as vectors of a diversity of pathogens. When nestling were 10 days old, we assigned wild great tit Parus major nests to one of two treatments, control and fumigated nests. The abundance of biting midges and blackflies captured during 3 days following the treatme...

  2. 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

  3. 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。

  4. Privacy-Preserving Important Passage Retrieval

    OpenAIRE

    Marujo, Luis; Portêlo, José; de Matos, David Martins; Neto, João P.; Gershman, Anatole; Carbonell, Jaime; Trancoso, Isabel; Raj, Bhiksha

    2014-01-01

    State-of-the-art important passage retrieval methods obtain very good results, but do not take into account privacy issues. In this paper, we present a privacy preserving method that relies on creating secure representations of documents. Our approach allows for third parties to retrieve important passages from documents without learning anything regarding their content. We use a hashing scheme known as Secure Binary Embeddings to convert a key phrase and bag-of-words representation to bit st...

  5. 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.

  6. Retrieval of vertical concentration profiles from OSIRIS UV-visible limb spectra

    Energy Technology Data Exchange (ETDEWEB)

    Strong, K.; Joseph, B.M.; Dosanjh, R. [Univ. of Toronto, Dept. of Physics, Toronto, Ontario (Canada); McDade, I.C. [York Univ., Dept. of Earth and Atmospheric Science, Toronto, Ontario (Canada); McLinden, C.A. [Univ. of California at Irvine, Dept. of Earth System Science, Irvine, California (United States); McConnell, J.C. [York Univ., Dept. of Earth and Atmospheric Science, Toronto, Ontario (Canada); Stegman, J.; Murtagh, D.P. [Stockholm Univ., Dept. of Meteorology, Stockholm (Sweden); Llewellyn, E.J. [Univ. of Saskatchewan, Dept. of Physics and Engineering Physics, Saskatoon, SK (Canada)

    2002-04-01

    The OSIRIS instrument, launched on the Odin satellite in February 2001, includes an optical spectrograph that will record UV-visible spectra of sunlight scattered from the limb over a range of tangent heights. These spectra will be used to retrieve vertical profiles of ozone, NO{sub 2}, OC1O, BrO, NO{sub 3}, O{sub 2}, and aerosols, for the investigation of both stratospheric and mesospheric processes, particularly those related to ozone chemistry. In this work, the retrieval of vertical profiles of trace-gas concentrations from OSIRIS limb-radiance spectra is described. A forward model has been developed to simulate these spectra, and it consists of a single-scattering radiative-transfer model with partial spherical geometry, trace-gas absorption, Mic scattering by stratospheric aerosols, a Lambertian surface contribution, and OSIRIS instrument response and noise. Number-density profiles have been retrieved by using optimal estimation (OE) to combine an a priori profile with the information from sets of synthetic 'measurements'. For ozone, OE has been applied both to limb radiances at one or more discrete wavelengths and to effective-column abundances retrieved over a broad spectral range using differential optical absorption spectroscopy (DOAS). The results suggest that, between 15 and 35 km, ozone number densities can be retrieved to 10% accuracy or better on 1 and 2 km grids and to 5% on a 5 km grid. The combined DOAS-OE approach has also been used to retrieve NO{sub 2} number densities, yielding 13% accuracy or better for altitudes from 18 to 36 km (in a 2 km grid. Differential optical absorption spectroscopy - optimal estimation retrievals of BrO and OC1O reproduce the true profiles above 15 km in the noise-free case, but the quality of the retrievals is highly sensitive to noise on the simulated OSIRIS spectra because of the weak absorption of these two gases. The development of inversion methods for the retrieval of trace-gas concentrations from

  7. Retrieval options study

    International Nuclear Information System (INIS)

    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;

  8. 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).

  9. 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 ...

  10. 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)

  11. Event-based personal retrieval

    OpenAIRE

    Bovey, John D.

    1996-01-01

    People who work in a research, academic or business environment often have personal information collections which are large enough to need retrieval aids. A major difference between personal information retrieval and normal document retrieval is that the items to be retrieved are often associated with events in the searcher's life and can be retrieved by their relationship to other events as well as by content. This paper describes some of the background to event-based retrieval and then desc...

  12. 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.

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

    OpenAIRE

    Levelt, P. F.; Wang, P.; P. Stammes; A. J. M. Piters; T. Vlemmix

    2010-01-01

    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 tr...

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

    OpenAIRE

    T. Vlemmix; Piters, A. J. M.; Stammes, P.; Wang, P.; P. F. Levelt

    2010-01-01

    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 tr...

  15. 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.

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

    International Nuclear Information System (INIS)

    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

  17. 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.

  18. 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.

    Directory of Open Access Journals (Sweden)

    Chelsea G Himsworth

    Full Text Available 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.

  19. 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.

  20. Content Based Video Retrieval

    Directory of Open Access Journals (Sweden)

    B.V.Patel

    2012-11-01

    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.

  1. 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.

  2. Changing Information Retrieval Behaviours

    DEFF Research Database (Denmark)

    Constantiou, Ioanna D.; Lehrer, Christiane; Hess, Thomas

    2014-01-01

    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....

  3. 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.

  4. UML MODELING AND SYSTEM ARCHITECTURE FOR AGENT BASED INFORMATION RETRIEVAL

    Directory of Open Access Journals (Sweden)

    D. Muhammad Noorul Mubarak

    2015-12-01

    Full Text Available In this current technological era, there is an enormous increase in the information available on web and also in the online databases. This information abundance increases the complexity of finding relevant information. To solve such challenges, there is a need for improved and intelligent systems for efficient search and retrieval. Intelligent Agents can be used for better search and information retrieval in a document collection. The information required by a user is scattered in a large number of databases. In this paper, the object oriented modeling for agent based information retrieval system is presented. The paper also discusses the framework of agent architecture for obtaining the best combination terms that serve as an input query to the information retrieval system. The communication and cooperation among the agents are also explained. Each agent has a task to perform in information retrieval.

  5. RETRIEVAL EVENTS EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    T. Wilson

    1999-11-12

    The purpose of this analysis is to evaluate impacts to the retrieval concept presented in the Design Analysis ''Retrieval Equipment and Strategy'' (Reference 6), from abnormal events based on Design Basis Events (DBE) and Beyond Design Basis Events (BDBE) as defined in two recent analyses: (1) DBE/Scenario Analysis for Preclosure Repository Subsurface Facilities (Reference 4); and (2) Preliminary Preclosure Design Basis Event Calculations for the Monitored Geologic Repository (Reference 5) The objective of this task is to determine what impacts the DBEs and BDBEs have on the equipment developed for retrieval. The analysis lists potential impacts and recommends changes to be analyzed in subsequent design analyses for developed equipment, or recommend where additional equipment may be needed, to allow retrieval to be performed in all DBE or BDBE situations. This analysis supports License Application design and therefore complies with the requirements of Systems Description Document input criteria comparison as presented in Section 7, Conclusions. In addition, the analysis discusses the impacts associated with not using concrete inverts in the emplacement drifts. The ''Retrieval Equipment and Strategy'' analysis was based on a concrete invert configuration in the emplacement drift. The scope of the analysis, as presented in ''Development Plan for Retrieval Events Evaluation'' (Reference 3) includes evaluation and criteria of the following: Impacts to retrieval from the emplacement drift based on DBE/BDBEs, and changes to the invert configuration for the preclosure period. Impacts to retrieval from the main drifts based on DBE/BDBEs for the preclosure period.

  6. A New Stemmer to Improve Information Retrieval

    Directory of Open Access Journals (Sweden)

    Wahiba Ben Abdessalem Karaa

    2013-07-01

    Full Text Available A stemming is a technique used to reduce words to their root form, by removing derivational andinflectional affixes. The stemming is widely used in information retrieval tasks. Many researchersdemonstrate that stemming improves the performance of information retrieval systems. Porter stemmer isthe most common algorithm for English stemming. However, this stemming algorithm has severaldrawbacks, since its simple rules cannot fully describe English morphology. Errors made by this stemmermay affect the information retrieval performance.The present paper proposes an improved version of the original Porter stemming algorithm for the Englishlanguage. The proposed stemmer is evaluated using the error counting method. With this method, theperformance of a stemmer is computed by calculating the number of understemming and overstemmingerrors. The obtained results show an improvement in stemming accuracy, compared with the originalstemmer, but also compared to other stemmers such as Paice and Lovins stemmers. We prove, in addition,that the new version of porter stemmer affects the information retrieval performance.

  7. 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...

  8. 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...

  9. Semantic-based surveillance video retrieval.

    Science.gov (United States)

    Hu, Weiming; Xie, Dan; Fu, Zhouyu; Zeng, Wenrong; Maybank, Steve

    2007-04-01

    Visual surveillance produces large amounts of video data. Effective indexing and retrieval from surveillance video databases are very important. Although there are many ways to represent the content of video clips in current video retrieval algorithms, there still exists a semantic gap between users and retrieval systems. Visual surveillance systems supply a platform for investigating semantic-based video retrieval. In this paper, a semantic-based video retrieval framework for visual surveillance is proposed. A cluster-based tracking algorithm is developed to acquire motion trajectories. The trajectories are then clustered hierarchically using the spatial and temporal information, to learn activity models. A hierarchical structure of semantic indexing and retrieval of object activities, where each individual activity automatically inherits all the semantic descriptions of the activity model to which it belongs, is proposed for accessing video clips and individual objects at the semantic level. The proposed retrieval framework supports various queries including queries by keywords, multiple object queries, and queries by sketch. For multiple object queries, succession and simultaneity restrictions, together with depth and breadth first orders, are considered. For sketch-based queries, a method for matching trajectories drawn by users to spatial trajectories is proposed. The effectiveness and efficiency of our framework are tested in a crowded traffic scene. PMID:17405446

  10. 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.

  11. Image Retrieval Method Based on Binary Color Co-occurrence Matrix%基于二进制颜色相关矩阵的图像检索方法

    Institute of Scientific and Technical Information of China (English)

    史婷婷; 吴明珠; 陈勇

    2011-01-01

    This paper proposes an image retrieval method based on binary color co-occurrence matrix named Binary Modified Color Co-occurrence Matrix(BMCCM). It uses "color invariant model of RGB quantity" to quantify the original image, calculates the color co-occurrence matrix of transformed image, gets the binarization of co-occurrence matrix, and uses Jaccard coefficient to measure the similarity between images to complete the image retrieval. Experimental results show that BMCCM is more accurate and efficient on retrieval than color histogram and color (auto) correlogram.%提出一种基于二进制颜色相关矩阵的图像检索方法BMCCM.该方法利用RGB分量颜色不变量模型对原始图像进行量化,计算变换后图像的颜色相关矩阵,对相关矩阵进行二值化,并利用Jaccard系数衡量图像特征间的相似度,完成图像的检索.实验结果表明,BMCCM 的检索准确度及效率明显高于颜色真方图和颜色(自)相关图.

  12. Sperm retrieval techniques for assisted reproduction

    Directory of Open Access Journals (Sweden)

    Sandro C. Esteves

    2011-10-01

    Full Text Available Different surgical methods such as PESA, MESA, TESA, TESE and micro-TESE have been developed to retrieve spermatozoa from either the epididymis or the testis according to the type of azoospermia, i.e., obstructive or non-obstructive. Laboratory techniques are used to remove contaminants, cellular debris, and red blood cells following collection of the epididymal fluid or testicular tissue. Surgically-retrieved spermatozoa may be used for intracytoplasmic sperm injection (ICSI and/or cryopreservation. In this article, we review the surgical procedures for retrieving spermatozoa from both the epididymis and the testicle and provide technical details of the commonly used methods. A critical analysis of the advantages and limitations of the current surgical methods to retrieve sperm from males with obstructive and non-obstructive azoospermia is presented along with an overview of the laboratory techniques routinely used to process surgically-retrieved sperm. Lastly, we summarize the results from the current literature of sperm retrieval, as well as the clinical outcome of ICSI in the clinical scenario of obstructive and non-obstructive azoospermia.

  13. 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

  14. Summary on the Methods of Documentary Manual Retrieval for Police%简述警察文献的手工检索途径

    Institute of Scientific and Technical Information of China (English)

    汪虹

    2011-01-01

    Utilization of documentary for police is an important mark to measure the level of policemen academy. Grasping documentary manual retrieval is not only speed up looking up documents but also improving research level.%警察文献的利用率是衡量警察学术水平的重要标志,掌握警察文献的检索方法可以加快查找文献的速度,提高学习和研究的水平。

  15. 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.

  16. Human factors analysis and design methods for nuclear waste retrieval systems. Volume III. User's guide for the computerized event-tree analysis technique

    International Nuclear Information System (INIS)

    This document provides detailed instructions for using the Computerized Event-Tree Analysis Technique (CETAT), a program designed to assist a human factors analyst in predicting event probabilities in complex man-machine configurations found in waste retrieval systems. The instructions contained herein describe how to (a) identify the scope of a CETAT analysis, (b) develop operator performance data, (c) enter an event-tree structure, (d) modify a data base, and (e) analyze event paths and man-machine system configurations. Designed to serve as a tool for developing, organizing, and analyzing operator-initiated event probabilities, CETAT simplifies the tasks of the experienced systems analyst by organizing large amounts of data and performing cumbersome and time consuming arithmetic calculations. The principal uses of CETAT in the waste retrieval development project will be to develop models of system reliability and evaluate alternative equipment designs and operator tasks. As with any automated technique, however, the value of the output will be a function of the knowledge and skill of the analyst using the program

  17. 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 < 712 nm) 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 (0.5 nm). 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 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

  18. RETIN AL: An Active Learning Strategy for Image Category Retrieval

    OpenAIRE

    Gosselin, Philippe-Henri; Cord, Matthieu

    2004-01-01

    International audience Active learning methods have been considered with an increasing interest in the content-based image retrieval (CBIR) community. In this article, we propose an effi- cient method based on active learning strategy to retrieve large image categories. At each feedback step, the system optimizes the image set presented to the user in order to speed up the retrieval. Experimental tests on COREL photo database have been carried out.

  19. 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.

  20. 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

  1. 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.

  2. 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...

  3. 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

  4. 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…

  5. 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.

  6. 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.

  7. Retrievability, ethics and democracy

    International Nuclear Information System (INIS)

    Ethics is always a social concern, an integrated part of laws and regulations. Treatment of ethics as a separate part in the decision making process is therefore always debatable. It cannot be introduced as an extraneous component to compensate for, or to improve, a morally flawed practice, and the margin for unethical practices is strongly circumscribed by regulation in the nuclear field, internationally. However, a discussion on different stakeholders and their different ethical concerns should always be welcome. One example is the implementer's views on ethics. Even if they are in complete parity with existing legal and regulatory goals, the goals may still represent the implementer's own motives and choices. Also, stakeholders may view the laws or regulations as unfair. In making the critique, the stakeholder simply formulates a separate political standpoint. Finally, an alternative discussion is to place existing regulations into an ethical perspective - adding a new dimension to the issues. Retrievability for high level waste repositories is often in focus in ethical discussions. Unfortunately, it is used in many ways and has become an unclear term. It may cover anything from planned recuperation to the property of waste being retrievable in years or tens of years, or in the distant time range of hundreds or thousands of years. The term retrievability is often proposed to cover mainly positive qualities such as the option of later changes to the repository or a new disposal concept. However, as ICRP and others have pointed out, it also implies the possibility of: i) operational exposures, ii) continuing risks of accidental releases, iii) financial provisions to cover operating costs and iv) continuing reliance on institutional control, thus imposing some burdens to future generations. In a certain sense, anything can be retrieved from any repository. There is therefore a need for a clear and operable definition of retrievability requirements, including the

  8. A FRAMEWORK FOR MRI IMAGE RETRIEVAL USING CURVELET TRANSFORM AND EUCLIDEAN DISTANCE

    OpenAIRE

    Rajakumar; Muttan

    2013-01-01

    Content Based Image Retrieval (CBIR) system supports users to retrieve relevant medical images based on their features. Current content based image retrieval systems are incapable of providing exact results to the users. To address this problem a consistent feature extraction method is required for content based medical image retrieval system to extract similar features from the images. In this study discrete curvelet based feature extraction technique is proposed to retrieve similar images a...

  9. 基于SURF特征贡献度矩阵的图像ROI选取与检索方法%ROI Selection and Image Retrieval Method Based on Contribution Matrix of SURF Features

    Institute of Scientific and Technical Information of China (English)

    薛峰; 顾靖; 崔国影; 徐珊; 徐娟

    2015-01-01

    In traditional image retrieval method, features need to be extracted within the whole region of image, which leads to high computation and semantic ambiguity. To address this issue, this paper proposes a technique to select region of interests(ROI), and carries out the retrieve process within the ROI. Firstly, SURF feature descriptor is used to extract local features and keypoints. Then, dynamic program is employed to calculate the sum of sub-matrix of feature points distribution, which is finally utilized to extract the ROI. Finally, we integrate the color, texture and shape features into a fused feature within ROI, and use nonlinear Gaussian distance function to retrieve images from the database with user input. Experimental results show that our proposed method has high conformity with human vision, and is effective for image retrieval.%传统的基于全局特征的图像检索方法中需要对整幅图像特征提取,计算复杂度大,且容易导致语义歧义。针对这一问题,提出一种基于 SURF 特征贡献度矩阵的 ROI 选取和图像检索方法。首先采用 SURF 算子提取图像局部特征,然后依据特征点的Hessian矩阵计算其贡献度矩阵,并将其应用到ROI检测中;在此基础上,融合并归一化ROI 的颜色、纹理以及形状等底层特征,利用非线性高斯距离函数进行相似度匹配,实现图像检索。实验结果表明,与已有算法相比,该算法提取的ROI与人类视觉意图一致性高,检索效果较好。

  10. 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.

  11. STUDIES ON RETRIEVAL OF THE TURBULIVITY OF ATMOSPHERIC BOUNDARY LAYER

    Institute of Scientific and Technical Information of China (English)

    WANG Ting-fang; HUANG Si-xun; XIANG Jie

    2006-01-01

    The variational adjoint method was applied to retrieving the turbulivity of the atmospheric Ekman boundary layer along with the regularization principle. The validity of the method was verified by using the idealized data, and then the turbulivity profile and the geostrophic wind profile were retrieved through it for real observational wind filed data.

  12. 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…

  13. Information Retrieval Using Association Lists

    OpenAIRE

    Marek Gajecki

    2004-01-01

    The paper presents the main models of information retrieval in text. The idea of association list and its use for information retrieval is introduced. The paper contains the evaluation results of the algorithms under discussion.

  14. 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

  15. Pareto-depth for Multiple-query Image Retrieval

    OpenAIRE

    Hsiao, Ko-Jen; Calder, Jeff; Hero III, Alfred O.

    2014-01-01

    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 (PFM) with efficient manifold ranking (EMR). We show that our proposed algorithm outp...

  16. Retrieval of similar chess positions

    OpenAIRE

    Ganguly, Debasis; LEVELING, JOHANNES; Jones, Gareth J.F.

    2014-01-01

    We address the problem of retrieving chess game positions similar to a given query position from a collection of archived chess games. We investigate this problem from an information retrieval (IR) perspective. The advantage of our proposed IR-based approach is that it allows using the standard inverted organization of stored chess positions, leading to an ecient retrieval. Moreover, in contrast to retrieving exactly identical board positions, the IR-based approach is able to provide approxim...

  17. Mobile medical image retrieval

    Science.gov (United States)

    Duc, Samuel; Depeursinge, Adrien; Eggel, Ivan; Müller, Henning

    2011-03-01

    Images are an integral part of medical practice for diagnosis, treatment planning and teaching. Image retrieval has gained in importance mainly as a research domain over the past 20 years. Both textual and visual retrieval of images are essential. In the process of mobile devices becoming reliable and having a functionality equaling that of formerly desktop clients, mobile computing has gained ground and many applications have been explored. This creates a new field of mobile information search & access and in this context images can play an important role as they often allow understanding complex scenarios much quicker and easier than free text. Mobile information retrieval in general has skyrocketed over the past year with many new applications and tools being developed and all sorts of interfaces being adapted to mobile clients. This article describes constraints of an information retrieval system including visual and textual information retrieval from the medical literature of BioMedCentral and of the RSNA journals Radiology and Radiographics. Solutions for mobile data access with an example on an iPhone in a web-based environment are presented as iPhones are frequently used and the operating system is bound to become the most frequent smartphone operating system in 2011. A web-based scenario was chosen to allow for a use by other smart phone platforms such as Android as well. Constraints of small screens and navigation with touch screens are taken into account in the development of the application. A hybrid choice had to be taken to allow for taking pictures with the cell phone camera and upload them for visual similarity search as most producers of smart phones block this functionality to web applications. Mobile information access and in particular access to images can be surprisingly efficient and effective on smaller screens. Images can be read on screen much faster and relevance of documents can be identified quickly through the use of images contained in

  18. 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…

  19. DORS: DDC Online Retrieval System.

    Science.gov (United States)

    Liu, Songqiao; Svenonius, Elaine

    1991-01-01

    Describes the Dewey Online Retrieval System (DORS), which was developed at the University of California, Los Angeles (UCLA), to experiment with classification-based search strategies in online catalogs. Classification structures in automated information retrieval are discussed; and specifications for a classification retrieval interface are…

  20. 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.

  1. 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.

  2. 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. PMID:26539859

  3. 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....... As a response to this call the ‘IIR evaluation model’ by Borlund (e.g., 2003a) is introduced. The objective of the IIR evaluation model is to facilitate IIR evaluation as close as possible to actual information searching and IR processes, though still in a relatively controlled evaluation environment, in which...

  4. Affective Music Information Retrieval

    OpenAIRE

    Wang, Ju-Chiang; Yang, Yi-Hsuan; Wang, Hsin-Min

    2015-01-01

    Much of the appeal of music lies in its power to convey emotions/moods and to evoke them in listeners. In consequence, the past decade witnessed a growing interest in modeling emotions from musical signals in the music information retrieval (MIR) community. In this article, we present a novel generative approach to music emotion modeling, with a specific focus on the valence-arousal (VA) dimension model of emotion. The presented generative model, called \\emph{acoustic emotion Gaussians} (AEG)...

  5. 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

  6. 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。

  7. 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.

  8. 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.

  9. 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.

  10. Tropospheric nitrogen dioxide column retrieval from ground-based zenith-sky DOAS observations

    Science.gov (United States)

    Tack, F.; Hendrick, F.; Goutail, F.; Fayt, C.; Merlaud, A.; Pinardi, G.; Hermans, C.; Pommereau, J.-P.; Van Roozendael, M.

    2015-06-01

    We present an algorithm for retrieving tropospheric nitrogen dioxide (NO2) vertical column densities (VCDs) from ground-based zenith-sky (ZS) measurements of scattered sunlight. The method is based on a four-step approach consisting of (1) the differential optical absorption spectroscopy (DOAS) analysis of ZS radiance spectra using a fixed reference spectrum corresponding to low NO2 absorption, (2) the determination of the residual amount in the reference spectrum using a Langley-plot-type method, (3) the removal of the stratospheric content from the daytime total measured slant column based on stratospheric VCDs measured at sunrise and sunset, and simulation of the rapid NO2 diurnal variation, (4) the retrieval of tropospheric VCDs by dividing the resulting tropospheric slant columns by appropriate air mass factors (AMFs). These steps are fully characterized and recommendations are given for each of them. The retrieval algorithm is applied on a ZS data set acquired with a multi-axis (MAX-) DOAS instrument during the Cabauw (51.97° N, 4.93° E, sea level) Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI) held from 10 June to 21 July 2009 in the Netherlands. A median value of 7.9 × 1015 molec cm-2 is found for the retrieved tropospheric NO2 VCDs, with maxima up to 6.0 × 1016 molec cm-2. The error budget assessment indicates that the overall error σTVCD on the column values is less than 28%. In the case of low tropospheric contribution, σTVCD is estimated to be around 39% and is dominated by uncertainties in the determination of the residual amount in the reference spectrum. For strong tropospheric pollution events, σTVCD drops to approximately 22% with the largest uncertainties on the determination of the stratospheric NO2 abundance and tropospheric AMFs. The tropospheric VCD amounts derived from ZS observations are compared to VCDs retrieved from off-axis and direct-sun measurements of the same MAX-DOAS instrument as well as to data

  11. 基于相似图像检索与字典学习的图像去噪算法%A Image Denoising Method Based on Similar Image Retrieval and Dictionary Learning

    Institute of Scientific and Technical Information of China (English)

    胡占强; 耿龙

    2016-01-01

    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。%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.

  12. 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.

  13. 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.

  14. 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.

  15. Estimating whale abundance using sparse hydrophone arrays

    OpenAIRE

    Harris, Danielle Veronica

    2012-01-01

    Passive acoustic monitoring has been used to investigate many aspects of marine mammal ecology, although methods to estimate absolute abundance and density using acoustic data have only been developed in recent years. The instrument configuration in an acoustic survey determines which abundance estimation methods can be used. Sparsely distributed arrays of instruments are useful because wide geographic areas can be covered. However, instrument spacing in sparse arrays is such that the same...

  16. Quantum image with high retrieval performance

    Science.gov (United States)

    Ruan, Yue; Chen, Hanwu; Liu, Zhihao; Tan, Jianing

    2016-02-01

    Quantum image retrieval is an exhaustive work due to exponential measurements. Casting aside the background of image processing, quantum image is a pure many-body state, and the retrieval task is a physical process named as quantum state tomography. Tomography of a special class of states, permutationally symmetric states, just needs quadratic measurement scales with the number of qubits. In order to take advantage of this result, we propose a method to map the main energy of the image to these states. First, we deduce that n+1 permutationally symmetric states can be constructed as bases of 2^n Hilbert space ( n qubits) at least. Second, we execute Schmidt decomposition by continually bipartite splitting of the quantum image (state). At last, we select n+1 maximum coefficients, do base transformation to map these coefficients to new bases (permutationally symmetric states). By these means, the quantum image with high retrieval performance can be gotten.

  17. 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

  18. Representation, indexing, and retrieval of moving objects

    Science.gov (United States)

    Ye, Huanzhuo; Gong, Jianya; Li, Deren; Pan, Jianping; Chen, Yumin

    2003-12-01

    Moving objects are complicated to manage because they involve temporal attributes as well as spatial attributes. There are two methods to represent the motion of moving objects, function method and sampling method. Motion state modeling, based on sampling method, can give object's position, orientation and their changes at a specific epoch, and encapsulates all the calculation by object orientation method. A big job is to search the motion state vectors efficiently, which can be performed with the help of 2n index trees. 2n index tree is an efficient index method to multi-dimensional data. Different kinds of motion data retrieval can be transformed to basic searching in 2n index trees. With proper operation algorithm, 2n index trees work well with the indexing and retrieval of moving objects.

  19. 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.

  20. Linking species abundance distributions in numerical abundance and biomass through simple assumptions about community structure

    OpenAIRE

    Henderson, Peter A.; Magurran, Anne E

    2010-01-01

    Species abundance distributions (SADs) are widely used as a tool for summarizing ecological communities but may have different shapes, depending on the currency used to measure species importance. We develop a simple plotting method that links SADs in the alternative currencies of numerical abundance and biomass and is underpinned by testable predictions about how organisms occupy physical space. When log numerical abundance is plotted against log biomass, the species lie within an approximat...

  1. A Method to Retrieve the Oceanic Absorption Coefficient Based on Artificial Neural Network%用人工神经网络方法反演水体吸收系数

    Institute of Scientific and Technical Information of China (English)

    朱金山; 梁士英; 苏循波

    2012-01-01

    The absorption coefficient of water is an inherent optical parameter and constitutes the foundation of research on water optics remote sensing. A method for retrieving the oceanic absorption coefficient using the data of remote sensing reflectance (Rrs) and based on the artificial neural network (ANN) is presented in this paper. The algorithm retrieves the oceanic absorption coefficient with 440 nm as its wavelength, using the situ data of remote sensing reflectance (Rrs) to establish BP neural network. 80% of the situ data of Rrs were used for training data set, and the other 20% were used for testing data set. The results show that making the right choice of the hidden layer joints, transfer function and train function is very important. If we choose the optimal hidden layer joints, transfer function and train function, the correlation coefficient between testing data and situ data can be as high as 0. 978, which shows that the method for retrieving the oceanic absorption coefficient based on the artificial neural network is effective.%吸收系数是水体的固有光学参数,是进行水体光学遥感研究的基础.讨论了一种基于人工神经网络(artificial neural networks,ANN)、利用遥感反射比数据反演水体吸收系数的方法.该方法用实测的水体遥感反射比(Rrs)数据集建立BP神经网络,用以反演水体在波长440nm处的吸收系数(α(440)).实测遥感反射比数据集的80%数据用于训练样本,20%数据用于预测样本.研究结果表明:正确选择神经网络的传递函数、训练函数和隐含层节点个数是至关重要的;用最优的传递函数、训练函数和隐含层节点个数得到的预测结果与实际测量结果的相关系数高达0.978,证明了该方法的可行性.

  2. 一种基于主题爬行模式的地理信息分布式检索方法%AGeographic Information Retrieval Methods Based on the Mode of Distributed Crawling

    Institute of Scientific and Technical Information of China (English)

    王小康; 邓硕; 吴博; 李景文

    2015-01-01

    当前网络中地理信息以几何形式递增,为了高效地从海量网络信息中检索出高质量的地理信息,本文提出了一种基于主题爬行的地理信息分布式检索方法。本文采用面向对象的方法将网络地理数据按照四元组的要求进行分解和组织,对地物实体的主题文本特征、地理空间特征、时间维特征等相关信息进行封装,建立四元组实体对象,实现了地理信息数据的相互集成与组织。引入MapReduce模式的并行处理机制完成对网页中地理信息数据的优化存储与索引,并且通过分别计算网页文本、地理文本与查询关键词的主题相关性对爬取的网页进行有序的排列,从而提供快捷、高效的地理信息主题查询。%Current geographic information network in order to geometric form is increasing, in order to efficiently retrieve from the massive network information of high quality geographic information, this paper proposes a geographic information retrieval methods based on distributed crawling crawling body.In this paper, by using object oriented method the network geographic data are decom-posed and organization in accordance four tuples of objects, , geographic features, time Victor syndrome and other related information package, the establishment of four tuple entity object, realization of the geographic information data integration and organization, en-hance organizational efficiency index of the source data.Parallel processing mechanism into MapReduce mode to accomplish optimal storage of geographic information data in web and retrieval, and by calculating the page relevance text, geography text with the query keywords are orderly arranged for crawling web pages, so as to provide geographic information subject fast, efficient query.

  3. 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

  4. Profile Based Information Retrieval

    Directory of Open Access Journals (Sweden)

    Athar shaikh,

    2011-04-01

    Full Text Available This paper present Profile Based information retrieval system(PBIR. This system provide the user to register with it and based on the users registered areas of interest the system searches the related and efficient information form the world wide web using the technique of web text mining and arranges the unstructured data into structured format and present it to the user. This system also stores the previously searched data and based on users areas of interest and rating awarded to the interest by the user his profile will be updated at particular scheduled time.

  5. 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.

  6. Information, conservation and retrieval

    International Nuclear Information System (INIS)

    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'

  7. 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`.

  8. 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.

  9. Abundances in galaxies

    International Nuclear Information System (INIS)

    Standard (or mildly inhomogeneous) Big Bang nucleosynthesis theory is well confirmed by abundance measurements of light elements up to 7Li and the resulting upper limit to the number of neutrino families confirmed in accelerator experiments. Extreme inhomogeneous models with a closure density in form of baryons seem to be ruled out and there is no evidence for a cosmic 'floor' to 9Be or heavier elements predicted in some versions of those models. Galaxies show a correlation between luminous mass and abundance of carbon and heavier elements, usually attributed to escape of hot gas from shallow potential wells. Uncertainties include the role of dark matter and biparametric behaviour of ellipticals. Spirals have radial gradients which may arise from a variety of causes. In our own Galaxy one can distinguish three stellar populations - disk, halo and bulge - characterised by differing metallicity distribution functions. Differential abundance effects are found among different elements in stars as a function of metallicity and presumably age, notably in the ratio of oxygen and α-particle elements to iron. These may eventually be exploitable to set a time scale for the formation of the halo, bulge and disk. (orig.)

  10. Interstellar Atomic Abundances

    CERN Document Server

    Jenkins, E B

    2003-01-01

    A broad array of interstellar absorption features that appear in the ultraviolet spectra of bright sources allows us to measure the abundances and ionization states of many important heavy elements that exist as free atoms in the interstellar medium. By comparing these abundances with reference values in the Sun, we find that some elements have abundances relative to hydrogen that are approximately consistent with their respective solar values, while others are depleted by factors that range from a few up to around 1000. These depletions are caused by the atoms condensing into solid form onto dust grains. Their strengths are governed by the volatility of compounds that are produced, together with the densities and velocities of the gas clouds. We may characterize the depletion trends in terms of a limited set of parameters; ones derived here are based on measurements of 15 elements toward 144 stars with known values of N(H I) and N(H2). In turn, these parameters may be applied to studies of the production, de...

  11. 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.

  12. Multi-angle Approach for Coherent Retrieval of Surface Reflectance and Atmosphere Optical Depth from CRISM Observations

    Science.gov (United States)

    Doute, S.; Ceamanos, X.

    2015-10-01

    This paper addresses the correction for aerosol effects in near-simultaneous multi-angle observations acquired by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter. In the targeted mode, CRISM senses planet Mars from the top of the atmosphere (TOA) using 11 viewing angles in 437 visible and infrared wavelengths, which allow it to provide unique information on the scattering properties of surface materials and atmospheric aerosols. In order to retrieve these data, however, appropriate strategies must be used to model the signal sensed by CRISM and compensate for aerosol contribution. In [2] we put forward an innovative inversion scheme of the model named Multi-angle Approach for Retrieval of Surface Reflectance from CRISM Observations (MARS-ReCO). Nevertheless this first version of MARS-ReCO requires a priori information about the scattering properties and the abundance of the atmospheric aerosols prior to the inversion. The proposed method retrieves conjointly the atmosphere optical depth (AOD) and the bidirectional reflectance factor (BRF) of surface materials as a function of wavelength. MARS-ReCO represents a substantial improvement regarding previous techniques as it takes into consideration in a coherent way the anisotropy of both the surface and the atmosphere scattering. Thus it provides more realistic surface and atmospheric products. Furthermore, MARSReCO is fast and provides error bars on the retrieved parameters.

  13. 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.

  14. 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.

  15. 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.

  16. Retrieval of the effective constitutive parameters of bianisotropic metamaterials.

    Science.gov (United States)

    Chen, Xudong; Wu, Bae-Ian; Kong, Jin Au; Grzegorczyk, Tomasz M

    2005-04-01

    We propose a method to retrieve the effective constitutive parameters of a slab of bianisotropic metamaterial composed of split-ring resonators from the measurement of the S parameters. Analytical inversion equations are derived for homogeneous loss-less bianisotropic media, and a numerical retrieval approach is presented for the case of lossy bianisotropic media. The method is verified both analytically and numerically, and it is shown that the results for various split-ring resonator metamaterials qualitatively corroborate the conclusions found in published papers. The proposed retrieval method can be used as a valuable tool for the study of anisotropic and bianisotropic properties of metamaterials. PMID:15903809

  17. 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.

  18. 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.

  19. 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.

  20. Multilevel resistive information storage and retrieval

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Phase retrieval and saddle-point optimization

    CERN Document Server

    Marchesini, S

    2006-01-01

    Iterative algorithms with feedback are amongst the most powerful and versatile optimization methods for phase retrieval. Among these, the hybrid input-output algorithm has demonstrated remarkable success in performing giga-element nonlinear optimization, escaping local minima and producing images at resolutions beyond the capabilities of lens-based optical methods. Here the input-output iteration is improved by a lower dimensional subspace saddle-point optimization.

  2. Tank Waste Retrieval Lessons Learned at the Hanford Site

    International Nuclear Information System (INIS)

    exception to the waste retrieval criteria for a specific tank. Tank waste retrieval has been conducted at the Hanford Site over the last few decades using a method referred to as Past Practice Hydraulic Sluicing. Past Practice Hydraulic Sluicing employs large volumes of DST supernatant and water to dislodge, dissolve, mobilize, and retrieve tank waste. Concern over the leak integrity of SSTs resulted in the need for tank waste retrieval methods capable of using smaller volumes of liquid in a more controlled manner. Retrieval of SST waste in accordance with HFFACO requirements was initiated at the Hanford Site in April 2003. New and innovative tank waste retrieval methods that minimize and control the use of liquids are being implemented for the first time. These tank waste retrieval methods replace Past Practice Hydraulic Sluicing and employ modified sluicing, vacuum retrieval, and in-tank vehicle techniques. Waste retrieval has been completed in seven Hanford Site SSTs (C-106, C-103, C-201, C-202, C-203, C-204, and S-112) in accordance with HFFACO requirements. Three additional tanks are currently in the process of being retrieved (C-108, C-109 and S-102) Preparation for retrieval of two additional SSTs (C-104 and C-110) is ongoing with retrieval operations forecasted to start in calendar year 2008. Tank C-106 was retrieved to a residual waste volume of 470 ft3 using oxalic acid dissolution and modified sluicing. An Appendix H exception request for Tank C-106 is undergoing review. Tank C-103 was retrieved to a residual volume of 351 ft3 using a modified sluicing technology. This approach was successful at reaching the TPA limits for this tank of less than 360 ft3and the limits of the technology. Tanks C-201, C-202, C-203, and C-204 are smaller (55,000 gallon) tanks and waste removal was completed in accordance with HFFACO requirements using a vacuum retrieval system. Residual waste volumes in each of these four tanks were less than 25 ft3. Tank S-112 retrieval was

  3. 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

  4. Methane and carbon dioxide total column retrievals from cloudy GOSAT soundings over the oceans

    Science.gov (United States)

    Schepers, D.; Butz, A.; Hu, H.; Hasekamp, O. P.; Arnold, S. G.; Schneider, M.; Feist, D. G.; Morino, I.; Pollard, D.; Aben, I.; Landgraf, J.

    2016-05-01

    We present a novel physics-based retrieval method to infer total column mixing ratios of methane (XCH4) and carbon dioxide (XCO2) from space-borne short-wavelength infrared (SWIR) Earth radiance observations over the cloud-covered ocean. In nadir observing geometry in the SWIR spectral range, backscattering at the ocean surface is negligible. Hence, space-borne radiance measurements of ocean scenes generally do not provide sufficient level to retrieve XCO2 and XCH4. Our approach specifically targets cloudy GOSAT ocean soundings to provide sufficient radiance signal in nadir soundings in ocean areas. Currently, exploiting space-borne SWIR soundings over oceans relies on soundings in Sun glint geometry, observing the specular solar reflection at the ocean surface. The glint observation mode requires cloud-free conditions and a suitable observation geometry, severely limiting their number and geographical coverage. The proposed method is based on the existing RemoTeC algorithm that is extensively used to retrieve CH4 and CO2 columns from GOSAT SWIR measurements over land. For ocean pixels, we describe light scattering by clouds and aerosols by a single-layer water cloud with Gaussian height distribution. We infer the height and the geometrical thickness of the cloud layer jointly with the droplet size and the number density and the column abundances of CO2, CH4, and H2O. The CO2 and CH4 column product is validated with ground-based total column measurements performed at eight stations from the TCCON network that are geographically close to an ocean coastline. For the TCCON site with the most robust statistics (Lauder, New Zealand), we find a retrieval bias of 0.36% for XCH4 combined with a standard deviation of retrieval errors of 1.12%. For XCO2, the bias is 0.51% combined with a standard deviation of 1.03%. Averaged over all TCCON sites, our retrievals are biased -0.01% for XCO2 and -0.32% for XCH4. The standard deviation of station biases amounts to 0.45% for XCO2

  5. Abundances of Jupiter's Trace Hydrocarbons From Voyager and Cassini

    OpenAIRE

    Nixon, Conor A.; Achterberg, Richard K.; Romani, Paul. N.; Allen, Mark; Zhang, Xi; Teanby, Nicholas A.; Irwin, Patrick G. J.; Flasar, F. Michael

    2010-01-01

    The flybys of Jupiter by the Voyager spacecraft in 1979, and over two decades later by Cassini in 2000, have provided us with unique datasets from two different epochs, allowing the investigation of seasonal change in the atmosphere. In this paper we model zonal averages of thermal infrared spectra from the two instruments, Voyager 1 IRIS and Cassini CIRS, to retrieve the vertical and meridional profiles of temperature, and the abundances of the two minor hydrocarbons, acetylene (C_2H_2) and ...

  6. A neural network-based method for merging ocean color and Argo data to extend surface bio-optical properties to depth: Retrieval of the particulate backscattering coefficient

    Science.gov (United States)

    Sauzède, R.; Claustre, H.; Uitz, J.; Jamet, C.; Dall'Olmo, G.; D'Ortenzio, F.; Gentili, B.; Poteau, A.; Schmechtig, C.

    2016-04-01

    The present study proposes a novel method that merges satellite ocean color bio-optical products with Argo temperature-salinity profiles to infer the vertical distribution of the particulate backscattering coefficient (bbp). This neural network-based method (SOCA-BBP for Satellite Ocean-Color merged with Argo data to infer the vertical distribution of the Particulate Backscattering coefficient) uses three main input components: (1) satellite-based surface estimates of bbp and chlorophyll a concentration matched up in space and time with (2) depth-resolved physical properties derived from temperature-salinity profiles measured by Argo profiling floats and (3) the day of the year of the considered satellite-Argo matchup. The neural network is trained and validated using a database including 4725 simultaneous profiles of temperature-salinity and bio-optical properties collected by Bio-Argo floats, with concomitant satellite-derived products. The Bio-Argo profiles are representative of the global open-ocean in terms of oceanographic conditions, making the proposed method applicable to most open-ocean environments. SOCA-BBP is validated using 20% of the entire database (global error of 21%). We present additional validation results based on two other independent data sets acquired (1) by four Bio-Argo floats deployed in major oceanic basins, not represented in the database used to train the method; and (2) during an AMT (Atlantic Meridional Transect) field cruise in 2009. These validation tests based on two fully independent data sets indicate the robustness of the predicted vertical distribution of bbp. To illustrate the potential of the method, we merged monthly climatological Argo profiles with ocean color products to produce a depth-resolved climatology of bbp for the global ocean.

  7. Conservation and retrieval of information

    International Nuclear Information System (INIS)

    High-level waste from nuclear power generation will remain radioactive for thousands of years even though 99% of the radioactivity will have decayed within the first millennium. For a hypothetical group involved in future actions to retrieve or repair a repository, information about its location, design, and content would be necessary. The need of such groups can be used to design the information that should be kept in a waste archive. Two main strategies exist for long-germ information transfer, one which links information thorough successive transfers of archived material and other forms of knowledge in society, and one - such as marking the site with a monument - relying upon a direct link from the present to the distant future. Digital methods are not recommended for long-term storage, but digital processing may be a valuable tool to structure information summaries, and in the creation of better long-lasting records. Advances in archive management should also be pursued to widen the choice of information carriers of high durability. In the Nordic countries, during the first few thousand years, and perhaps up to the next period of glaciation, monuments at a repository site may be used to warn the public of the presence of dangerous waste. But messages from such markers may pose interpretation problems as we have today for messages left by earlier societies such as rune inscriptions. Since the national borders may change in the time scale relevant for nuclear waste, the creation of an international archive for all radioactive wastes would represent an improvement as regards conservation and retrieval of information. (EG)

  8. Variational assimilation in combination with the regularization method for sea level pressure retrieval from QuikSCAT scatterometer data I: Theoretical frame construction

    International Nuclear Information System (INIS)

    A new method of constructing a sea level pressure field from satellite microwave scatterometer measurements is presented. It is based on variational assimilation in combination with a regularization method using geostrophic vorticity to construct a sea level pressure field from scatterometer data that are given in this paper, which offers a new idea for the application of scatterometer measurements. Firstly, the geostrophic vorticity from the scatterometer data is computed to construct the observation field, and the vorticity field in an area and the sea level pressure on the borders are assimilated. Secondly, the gradient of sea level pressure (semi-norm) is used as the stable functional to educe the adjoint system, the adjoint boundary condition and the gradient of the cost functional in which a weight parameter is introduced for the harmony of the system and the Tikhonov regularization techniques in inverse problem are used to overcome the ill-posedness of the assimilation. Finally, the iteration method of the sea level pressure field is developed. (geophysics, astronomy, and astrophysics)

  9. Variational assimilation in combination with the regularization method for sea level pressure retrieval from QuikSCAT scatterometer data I: Theoretical frame construction

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

    A new method of constructing a sea level pressure field from satellite microwave scatterometer measurements is presented.It is based on variational assimilation in combination with a regularization method using geostrophic vorticity to construct a sea level pressure field from scatterometer data that are given in this paper,which offers a new idea for the application of scatterometer measurements.Firstly,the geostrophic vorticity from the scatterometer data is computed to construct the observation field,and the vorticity field in an area and the sea level pressure on the borders are assimilated.Secondly,the gradient of sea level pressure (semi-norm) is used as the stable functional to educe the adjoint system,the adjoint boundary condition and the gradient of the cost functional in which a weight parameter is introduced for the harmony of the system and the Tikhonov regularization techniques in inverse problem are used to overcome the ill-posedness of the assimilation.Finally,the iteration method of the sea level pressure field is developed.

  10. Contextual Bandits for Information Retrieval

    NARCIS (Netherlands)

    K. Hofmann; S. Whiteson; M. de Rijke

    2011-01-01

    In this paper we give an overview of and outlook on research at the intersection of information retrieval (IR) and contextual bandit problems. A critical problem in information retrieval is online learning to rank, where a search engine strives to improve the quality of the ranked result lists it pr

  11. 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.

  12. Metadata for Content-Based Image Retrieval

    OpenAIRE

    Adrian Sterca; Daniela Miron

    2010-01-01

    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.

  13. Assessment of methods for land surface temperature retrieval from Landsat-5 TM images applicable to multiscale tree-grass ecosystem modeling

    DEFF Research Database (Denmark)

    Vlassova, Lidia; Perez-Cabello, Fernando; Nieto Solana, Hector;

    2014-01-01

    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...... 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...

  14. Re-ranking by Local Re-scoring for Video Indexing and Retrieval

    OpenAIRE

    Safadi, Bahjat; Quénot, Georges

    2011-01-01

    Poster session: information retrieval International audience Video retrieval can be done by ranking the samples according to their probability scores that were predicted by classifiers. It is often possible to improve the retrieval performance by re-ranking the samples. In this paper, we proposed a re-ranking method that improves the performance of semantic video indexing and retrieval, by re-evaluating the scores of the shots by the homogeneity and the nature of the video they belong t...

  15. Global Descriptor Attributes Based Content Based Image Retrieval of Query Images

    OpenAIRE

    Jaykrishna Joshi; Dattatray Bade

    2015-01-01

    The need for efficient content-based image retrieval system has increased hugely. Efficient and effective retrieval techniques of images are desired because of the explosive growth of digital images. Content based image retrieval (CBIR) is a promising approach because of its automatic indexing retrieval based on their semantic features and visual appearance. In this proposed system we investigate method for describing the contents of images which characterizes images by global des...

  16. 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.

  17. 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.

  18. 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.

  19. International workshop on phase retrieval and coherent scattering. Coherence 2005

    International Nuclear Information System (INIS)

    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

  20. TEA: A Code for Calculating Thermochemical Equilibrium Abundances

    OpenAIRE

    Blecic, Jasmina; Harrington, Joseph; Bowman, M. Oliver

    2015-01-01

    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. (1958) and Eriksson (1971). 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 o...

  1. Abundance, Excess, Waste

    Directory of Open Access Journals (Sweden)

    Rox De Luca

    2016-02-01

    Her recent work focuses on the concepts of abundance, excess and waste. These concerns translate directly into vibrant and colourful garlands that she constructs from discarded plastics collected on Bondi Beach where she lives. The process of collecting is fastidious, as is the process of sorting and grading the plastics by colour and size. This initial gathering and sorting process is followed by threading the components onto strings of wire. When completed, these assemblages stand in stark contrast to the ease of disposability associated with the materials that arrive on the shoreline as evidence of our collective human neglect and destruction of the environment around us. The contrast is heightened by the fact that the constructed garlands embody the paradoxical beauty of our plastic waste byproducts, while also evoking the ways by which those byproducts similarly accumulate in randomly assorted patterns across the oceans and beaches of the planet.

  2. 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%.

  3. 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] $=-0.48 \\pm 0.02$.

  4. Testing Relationships between Energy and Vertebrate Abundance

    International Nuclear Information System (INIS)

    Understanding what drives variation in the abundance of organisms is fundamental to evolutionary ecology and wildlife management. Yet despite its importance, there is still great uncertainty about the main factors influencing variation in vertebrate abundance across taxa. We believe valuable knowledge and increased predictive power could be gained by taking into account both the intrinsic factors of species and the extrinsic factors related to environmental surroundings in the commonly cited RQ model, which provides a simple conceptual framework valid at both the interspecific and the intraspecific scales. Approaches comparing studies undertaken at different spatial and taxonomic scales could be key to our ability to better predict abundance, and thanks to the increased availability of population size data, global geographic datasets, and improved comparative methods, there might be unprecedented opportunities to (1) gain a greater understanding of vertebrate abundance patterns and (2) test existing theories on free-ranging animals.

  5. The impact of cloud vertical profile on liquid water path retrieval based on the bispectral method: A theoretical study based on large-eddy simulations of shallow marine boundary layer clouds

    Science.gov (United States)

    Miller, Daniel J.; Zhang, Zhibo; Ackerman, Andrew S.; Platnick, Steven; Baum, Bryan A.

    2016-04-01

    Passive optical retrievals of cloud liquid water path (LWP), like those implemented for Moderate Resolution Imaging Spectroradiometer (MODIS), rely on cloud vertical profile assumptions to relate optical thickness (τ) and effective radius (re) retrievals to LWP. These techniques typically assume that shallow clouds are vertically homogeneous; however, an adiabatic cloud model is plausibly more realistic for shallow marine boundary layer cloud regimes. In this study a satellite retrieval simulator is used to perform MODIS-like satellite retrievals, which in turn are compared directly to the large-eddy simulation (LES) output. This satellite simulator creates a framework for rigorous quantification of the impact that vertical profile features have on LWP retrievals, and it accomplishes this while also avoiding sources of bias present in previous observational studies. The cloud vertical profiles from the LES are often more complex than either of the two standard assumptions, and the favored assumption was found to be sensitive to cloud regime (cumuliform/stratiform). Confirming previous studies, drizzle and cloud top entrainment of dry air are identified as physical features that bias LWP retrievals away from adiabatic and toward homogeneous assumptions. The mean bias induced by drizzle-influenced profiles was shown to be on the order of 5-10 g/m2. In contrast, the influence of cloud top entrainment was found to be smaller by about a factor of 2. A theoretical framework is developed to explain variability in LWP retrievals by introducing modifications to the adiabatic re profile. In addition to analyzing bispectral retrievals, we also compare results with the vertical profile sensitivity of passive polarimetric retrieval techniques.

  6. Influences due to aerosol particles (Including Yellow Sands), water vapor on a skin sea surface temperature (SSST) estimation for the proposed iteration method for SSST retrieval

    International Nuclear Information System (INIS)

    Radiative Transfer Equation (RTE) in the thermal infrared wavelength region is expressed as a Fred Holm type of integral equation and is essentially non-linear so that it is not easy to solve in general. Linearized inversion and iterative methods are introduced to solve the RTE. As results of the sensitivity analysis of aerosol particles on RTE, it is found that the most sensitive aerosol type is navy maritime followed by maritime, urban, desert, rural and tropospheric aerosols if the meteorological ranges are totally identical. In addition to that, it is also found that Skin Sea Surface Temperature (SSST) estimation error is sensitive to the altitude of the dust type of aerosl particles

  7. 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.

  8. A Comparison Study on Retrieval Orthodontics Images through Two Approaches

    OpenAIRE

    Wu Chen; Wang Yuanyuan

    2014-01-01

    Orthodontics image retrieval is a very important job for aiding doctors to diagnose orthodontic diseases by providing successful treatment method in their history. Patients, ordinarily having nervous sense and no grasp about their current ill situation and therefore being afraid to get dealt with by doctors, can get confidence on their curing if they learn how their diseases were treated and what the result is after treatment. The paper uses three different methods to retrieve target image in...

  9. Ontology mapping method for retrieval of heterogeneous parametric feature models%面向异构参数化特征模型检索的本体映射方法

    Institute of Scientific and Technical Information of China (English)

    秦飞巍; 李路野; 高曙明

    2013-01-01

    Aiming at difficulties in retrieving and reusing heterogeneous parametric feature models,an ontology based feature representation model was built,and a new feature ontology mapping method was proposed for representing heterogeneous product feature model information semantically.An ontology based feature model database was constructed to support the retrieval and reuse of heterogeneous parametric feature models.The ontology mapping was occurred between application feature ontology and common feature ontology,and the mapping of one to one,one to many and many to one were realized based on the feature matching with similarity evaluation.The reasoning ability of ontology and Semantic Web Rule Language (SWRL) were used for verifying the ontology mapping results to ensure the accuracy.The ontology mapping algorithm was implemented by programming.The effectiveness and feasibility of proposed method were validated by examples.%针对异构参数化特征模型难以检索重用的问题,建立了基于本体的特征表示模式,提出一种新的特征本体映射方法,将产品模型特征信息进行统一的语义描述,建立基于本体的特征模型库以有效地支持异构参数化特征模型的检索和重用.本体映射在系统特征本体和公共特征本体之间进行,基于相似性评价指标进行的特征概念匹配能够实现一对一、一对多和多对一的映射,并利用本体的推理能力和语义网规则描述语言对匹配结果进行检查,以保证本体映射的准确性.编程实现了本体映射算法,通过实例检验了方法的可行性和有效性.

  10. 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 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.

  11. 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

  12. Retrievable IVC Square Stent Filter: Experimental Study

    International Nuclear Information System (INIS)

    Purpose: In vitro and in vivo evaluation of a new retrievable, home-made, inferior vena cava (IVC) Square stent filter (SSF) with two trapping levels. Methods: In vitro, the SSF was compared in a flow model with the stainless steel Greenfield filter (SGF) for emboli- trapping efficiency by serially passing 300 emboli of 3 and 6 mm in diameter and 15-30 mm in length in each type of filter. Nine swine were used for the in vivo testing of the SSF for deployment and retrievability, emboli-trapping efficiency, stability, and self-centering ability and two were used (total of 11 swine) for testing repositioning and retrievability of the SSF at 2 weeks and for gross and histologic IVC changes at 2 months. Results: In vitro, the SSF and SGF had similar efficiency in trapping large emboli but the SSF had significantly better efficiency than the SGF for trapping all sizes of emboli (91.7% vs 81%), medium size emboli (93% vs 80%), and small emboli (86% vs 69%). Efficiency decreased in both filters from the first to the fifth embolus in each series but was still significantly better for the SSF. With the SSF, 89% of emboli were caught at the primary and 11% at the secondary filtration level. In the nine animals used for acute studies, the SSF was easily placed in all 27 attempts, assumed a central position 26 times, and was easily retrieved in 21 of 22 attempts. One tilted filter needed additional manipulation for retrieval. During emboli injection in five swine, the SSF had 97.2% emboli-trapping efficiency and demonstrated good stability. In the two animals used for longer-term evaluation, the filters were easily retrieved 2 weeks after implantation. Histologic evaluation at 2 months showed neointimal proliferation around the SSF wires in contact with the IVC wall, which was otherwise normal. Conclusion: The SSF is a promising filter. It is easy to place and retrieve, is stable after placement, and has high efficiency for trapping emboli. Promising results justify further

  13. 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.

  14. Interactive Information Retrieval: Context and Basic Notions

    OpenAIRE

    David Robins

    2000-01-01

    his paper provides an introduction to interactive information retrieval--the study of human interaction with information retrieval systems. Interactive information retrieval may be contrasted with the "system-centered" view of information retrieval in which changes to information retrieval system variables are manipulated in isolation from users in laboratory situations. The paper elucidates current models of interactive information retrieval, namely, the episodic model, the stratif...

  15. Wave impedance retrieving via Bloch modes analysis

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Ha, S.; Sukhorukov, A.;

    2011-01-01

    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......-ciples violation, like antiresonance behaviour with Im(ε) 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...

  16. Music Information Retrieval Meets Music Education

    OpenAIRE

    Dittmar, Christian; Cano, Estefanía; Abeßer, Jakob; Grollmisch, Sascha

    2012-01-01

    This paper addresses the use of Music Information Retrieval (MIR) techniques in music education and their integration in learning software. A general overview of systems that are either commercially available or in research stage is presented. Furthermore, three well-known MIR methods used in music learning systems and their state-of-the-art are described: music transcription, solo and accompaniment track creation, and generation of performance instructions. As a representative example of a m...

  17. 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.

  18. 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...

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  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. 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.

  6. 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.

  7. Hierarchical and binary spatial descriptors for lung nodule image retrieval.

    Science.gov (United States)

    Ng, Gillian; Song, Yang; Cai, Weidong; Zhou, Yun; Liu, Sidong; Feng, David Dagan

    2014-01-01

    With the increasing amount of image data available for cancer staging and diagnosis, it is clear that content-based image retrieval techniques are becoming more important to assist physicians in making diagnoses and tracking disease. Domain-specific feature descriptors have been previously shown to be effective in the retrieval of lung tumors. This work proposes a method to improve the rotation invariance of the hierarchical spatial descriptor, as well as presents a new binary descriptor for the retrieval of lung nodule images. The descriptors were evaluated on the ELCAP public access database, exhibiting good performance overall. PMID:25571476

  8. 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.

  9. 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.

  10. Catalogue Retrieval: A Library Economy

    Science.gov (United States)

    Ready, William

    1970-01-01

    An evaluation of the Information Dynamics Corporation Retrieval System in an academic library, describing the specification of the machine and the various reader printers tested at Mills Memorial Library, McMaster University. (Author)

  11. 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.

  12. 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. PMID:24696643

  13. 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.

  14. Density-based retrieval from high-similarity image databases

    DEFF Research Database (Denmark)

    Hansen, Michael Edberg; Carstensen, Jens Michael

    2004-01-01

    Many image classification problems can fruitfully be thought of as image retrieval in a "high similarity image database" (HSID) characterized by being tuned towards a specific application and having a high degree of visual similarity between entries that should be distinguished. We introduce a...... method for HSID retrieval using a similarity measure based on a linear combination of Jeffreys-Matusita distances between distributions of local (pixelwise) features estimated from a set of automatically and consistently defined image regions. The weight coefficients are estimated based on optimal...... retrieval performance. Experimental results on the difficult task of visually identifying clones of fungal colonies grown in a petri dish and categorization of pelts show a high retrieval accuracy of the method when combined with standardized sample preparation and image acquisition....

  15. 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.

  16. 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?

  17. 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%.

  18. Polar Embedding for Aurora Image Retrieval.

    Science.gov (United States)

    Yang, Xi; Gao, Xinbo; Tian, Qi

    2015-11-01

    Exploring the multimedia techniques to assist scientists for their research is an interesting and meaningful topic. In this paper, we focus on the large-scale aurora image retrieval by leveraging the bag-of-visual words (BoVW) framework. To refine the unsuitable representation and improve the retrieval performance, the BoVW model is modified by embedding the polar information. The superiority of the proposed polar embedding method lies in two aspects. On the one hand, the polar meshing scheme is conducted to determine the interest points, which is more suitable for images captured by circular fisheye lens. Especially for the aurora image, the extracted polar scale-invariant feature transform (polar-SIFT) feature can also reflect the geomagnetic longitude and latitude, and thus facilitates the further data analysis. On the other hand, a binary polar deep local binary pattern (polar-DLBP) descriptor is proposed to enhance the discriminative power of visual words. Together with the 64-bit polar-SIFT code obtained via Hamming embedding, the multifeature index is performed to reduce the impact of false positive matches. Extensive experiments are conducted on the large-scale aurora image data set. The experimental result indicates that the proposed method improves the retrieval accuracy significantly with acceptable efficiency and memory cost. In addition, the effectiveness of the polar-SIFT scheme and polar-DLBP integration are separately demonstrated. PMID:26068312

  19. Order effect in interactive information retrieval evaluation

    DEFF Research Database (Denmark)

    Clemmensen, Melanie Landvad; Borlund, Pia

    2016-01-01

    Purpose – The purpose of this paper is to report a study of order effect in interactive information retrieval (IIR) studies. The phenomenon of order effect is well-known, and it is the main reason why searches are permuted (counter-balanced) between test participants in IIR studies. However...... the perspective of IIR. Keywords Evaluation, Research methods, Information retrieval, User studies, Searching, Information searches...... of such studies. Due to the limited sample of 20 test participants (Library and Information Science (LIS) students) inference statistics is not applicable; hence conclusions can be drawn from this sample of test participants only. Originality/value – Only few studies in LIS focus on order effect and none from...

  20. 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.

  1. 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.

  2. Concepts for Waste Retrieval and Alternate Storage of Radioactive Waste

    International Nuclear Information System (INIS)

    The primary purpose of this technical report is to present concepts for retrieval operations, equipment to be used, scenarios under which waste retrieval operations will take place, methods for responding to potential retrieval problems, and compliance with the preclosure performance objectives of 10 CFR 63.111(a) and (b) [DIRS 156605] during the retrieval of waste packages from the subsurface repository. If a decision for retrieval is made for any or all of the waste, the waste to be retrieved would be dispositioned in accordance with the regulations applicable at the time. The secondary purpose is to present concepts for the design, construction, and operation of an alternate storage facility. The alternate storage facility would temporarily house the retrieved waste until final disposition is established. The concept presented is consistent with current practices and regulations for the protection of public health and safety and the environment, it demonstrates the feasibility of such a facility, if required, and it is based on the consideration for keeping radiation exposure as low as is reasonably achievable (ALARA)

  3. 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.

  4. Martian thermospheric temperatures retrieved from CO2 + SPICAM dayglow measurements

    OpenAIRE

    Stiepen, Arnaud; Gérard, Jean-Claude; Bougher, S.; Montmessin, F.

    2012-01-01

    A large dataset of dayside grazing limb CO2+ observations performed by the SPICAM (Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars) instrument on board Mars Express is analyzed to retrieve Martian thermospheric temperature, as well as its variation with solar activity, season and latitude. The method permits to retrieve the temperature from the scale height of the CO2+ emission. We also present puzzling features such as limb profiles exhibiting multiple peaks and t...

  5. An Artificial Intelligence Environment for Information Retrieval Research

    OpenAIRE

    France, Robert K.; Edward A Fox

    1988-01-01

    The CODER (COmposite Document Expert/Extended/Effective Retrieval) project is a multi-year effort to investigate how best to apply artificial intelligence methods to increase the effectiveness of information retrieval systems. Particular attention is being given to analysis and representation of heterogeneous documents, such as electronic mail digests or messages, which vary widely in style, length, topic,and structure. In order to ensure system adaptability and to allow reconfiguration for c...

  6. Retrieval of Planetary Rotation and Albedo from DSCOVR data

    OpenAIRE

    Kane, S.R.; Domagal-Goldman, S. D.; Herman, J.R.; Robinson, T. D; Stine, A. R.

    2015-01-01

    The field of exoplanets has rapidly expanded from the exclusivity of exoplanet detection to include exoplanet characterization. A key step towards this characterization will be retrieval of planetary albedos and rotation rates from highly undersampled imaging data. The Deep Space Climate Observatory (DSCOVR) provides a unique opportunity to test such retrieval methods using high cadence data of the sunlit surface of the Earth. There are two NASA instruments on board DSCOVR that can be used to...

  7. EFFICIENT RETRIEVAL TECHNIQUES FOR IMAGES USING ENHANCED UNIVARIATE TRANSFORMATION APPROACH

    OpenAIRE

    DR.S.P.VICTOR,; MRS.V.NARAYANI,; Rajkumar, S.

    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...

  8. 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.

  9. Using Statistical Moment Invariants and Entropy in Image Retrieval

    OpenAIRE

    Ismail I. Amr; Mohamed Amin; Passent El-Kafrawy; Sauber, Amr M.

    2010-01-01

    Although content-based image retrieval (CBIR) is not a new subject, it keeps attracting more and more attention, as the amount of images grow tremendously due to internet, inexpensive hardware and automation of image acquisition. One of the applications of CBIR is fetching images from a database. This paper presents a new method for automatic image retrieval using moment invariants and image entropy, our technique could be used to find semi or perfect matches based on query-by-example manner,...

  10. Averaging kernels for DOAS total-column satellite retrievals

    OpenAIRE

    H. J. Eskes; Boersma, K. F.

    2003-01-01

    The Differential Optical Absorption Spectroscopy (DOAS) method is used extensively to retrieve total column amounts of trace gases based on UV-visible measurements of satellite spectrometers, such as ERS-2 GOME. In practice the sensitivity of the instrument to the tracer density is strongly height dependent, especially in the troposphere. The resulting tracer profile dependence may introduce large systematic errors in the retrieved columns that are difficul...

  11. Barcode Annotations for Medical Image Retrieval: A Preliminary Investigation

    OpenAIRE

    Tizhoosh, Hamid R.

    2015-01-01

    This paper proposes to generate and to use barcodes to annotate medical images and/or their regions of interest such as organs, tumors and tissue types. A multitude of efficient feature-based image retrieval methods already exist that can assign a query image to a certain image class. Visual annotations may help to increase the retrieval accuracy if combined with existing feature-based classification paradigms. Whereas with annotations we usually mean textual descriptions, in this paper barco...

  12. 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 ...

  13. Overview of the 2005 cross-language image retrieval track (ImageCLEF)

    OpenAIRE

    Clough, P.; Müller, H; Deselaers, T.; Lehmann, T.; Grubinger, M.; J. Jensen; Hersh, W.

    2005-01-01

    The purpose of this paper is to outline efforts from the 2005 CLEF crosslanguage image retrieval campaign (ImageCLEF). The aim of this CLEF track is to explore the use of both text and content-based retrieval methods for cross-language image retrieval. Four tasks were offered in the ImageCLEF track: a ad-hoc retrieval from an historic photographic collection, ad-hoc retrieval from a medical collection, an automatic image annotation task, and a user-centered (interactive) evaluation task th...

  14. The effects of varied antigen retrieval methods on immunohistochemistry of functional proteins in retinal paraffin section%不同抗原修复法对视网膜石蜡切片相关功能蛋白表达检测的影响

    Institute of Scientific and Technical Information of China (English)

    李颖; 胡运韬; 马汀; 马志中

    2010-01-01

    Background Antigen retrieval method is the key of improving the successful rate of immunohistochemical assay in paraffin sections.To study an available method of antigen retrieval is a goal to achieve both good immunochemistry result and preserving retinal proteins.ObjectiveThe aim of present study is to investigate tyrosin digestion,high-temperature heat pressure,water bath heating and microwave repair in antigen retrieval for retinal tissues.MethodsRetinal tissue was isolated and obtained from clean Chinchilla rabbits.Four hundreds retinal paraffin sections were prepared.Four kinds of antigen retrieval methods for retinal tissue including tyrosin digestion,high-temperature heat pressure,water bath heating and microwave repair were used respectively.The depigmentated retinal paraffin section without antigen retrieval was used as control.The positive rates of expression of CRALBP,Rhodopsin and opsin proteins were evaluated and compared among four kinds of antigen retrieval methods by immunochemistry.ResultsCRALBP,Rhodopsin and opsin protein was positively expressed in cytoplasm of retinal pigment epithelial cells and the outer segment of photoreceptor respectively.No significant difference was found in the positive expression rates of these three proteins among four kinds of antigen retrieval methods (P>0.05),but the differences in tissue integrity and background staining were statistically significant (P<0.01).The structural damage of retina included loss and pucker of scalera,crack of nucleus and abnormal background stain in high-temperature heat pressure method,water bath heating method and microwave retrieval method.However,stable CRALBP,Rhodopsin and opsin protein expression and strain effectiveness,clear background without unspecific staining and integrated tissue were seen in tyrosin digestion method.ConclusionDuring the clinical pathology analysis of retinal tissue,the application of tyrosin digestion in antigen retrieval could obtain a better

  15. 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.

  16. 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.

  17. Galactic abundance gradients from Cepheids : On the iron abundance gradient around 10-12 kpc

    OpenAIRE

    Lemasle, B.; Francois, P.; Piersimoni, A.; Pedicelli, S.; Bono, G.; Laney, C. D.; Primas, F.; Romaniello, M.

    2008-01-01

    Context: Classical Cepheids can be adopted to trace the chemical evolution of the Galactic disk since their distances can be estimated with very high accuracy. Aims: Homogeneous iron abundance measurements for 33 Galactic Cepheids located in the outer disk together with accurate distance determinations based on near-infrared photometry are adopted to constrain the Galactic iron gradient beyond 10 kpc. Methods: Iron abundances were determined using high resolution Cepheid spectra collected wit...

  18. 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…

  19. Clonal growth and plant species abundance

    Science.gov (United States)

    Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

    2014-01-01

    Background and Aims Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf–height–seed) traits and by actual performance in the botanical garden. Methods Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area – height – seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. Key Results After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Conclusions Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially

  20. 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。