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Sample records for cinnabar reconstructive phase

  1. The pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 at high pressure: a mechanism for the zinc blende to cinnabar reconstructive phase transition

    CERN Document Server

    Kozlenko, D P; Ehm, L; Hull, S; Savenko, B N; Shchennikov, V V; Voronin, V I

    2003-01-01

    The structure of the pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 has been studied by x-ray and neutron powder diffraction at pressures up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P approx 1 GPa. A phenomenological model of this reconstructive phase transition based on a displacement mechanism is proposed. Analysis of the geometrical relationship between the zinc blende and the cinnabar phases has shown that the possible order parameter for the zinc blende-cinnabar structural transformation is the spontaneous strain e sub 4. This assignment agrees with the previously observed high pressure behaviour of the elastic constants of some mercury chalcogenides.

  2. Phase Transition and EOS of Cinnabar (α-HgS) at High Pressure and High Temperature

    Institute of Scientific and Technical Information of China (English)

    FAN Da-Wei; ZHOU Wen-Ge; LIU Cong-Qiang; WAN Fang; XING Yin-Suo; LIU Jing; LI Yan-Chun; XIE Hong-Sen

    2009-01-01

    @@ Phase relations and equation of state (EOS) of natural cinnabar (α-HgS) are investigated by high-pressure and high-temperature synchrotron x-ray powder diffraction. The unambiguous cinnabar-rocksalt structure phase boundaries are determined to be Plower(Gpa)=15.54-0.014T(℃) and Pupper(Gpa)= 23.84 - 0.014T(℃) at 300--623K. With K' axed at 4, we obtain K0 = 37(4) Gpa, ( K/ T)p=-0.025(2) GPaK-1, and α0= 3.79(20)× 10-5 K-1 for the cinnabar phase of α-HgS. The ( K/ T)p and α0 of cinnabar phase are obtained for the first time. A nearly isotropic compression of cinnabar phase is observed by linear regressions.

  3. In vitro investigation on cinnabar dissolution

    Institute of Scientific and Technical Information of China (English)

    ZENG Kewu; WANG Qi; YANG Xiaoda; WANG Kui

    2007-01-01

    To study the effects of different chemical factors in the gastrointestinal tract, I.e. pH, proteins, amino acids,ionic strength and Na2S, on the dissolution of cinnabar. The content of the total mercury in various dissolutions of cinnabar was analyzed by UV/VIS Spectrophotometer. Laser Particle Size Analyzer measured the particle distributionsin the dissolution of cinnabar. The chemical species of dis-solved substance of cinnabar in the presence of Na2S were determined using ESI-MS. The results indicate that the solu-bility of cinnabar could be increased significantly in the pres-ence ofNa2S/S0, and strong acidic pH, respectively. While theinfluence of thiol amino acid on promoting dissolutionremains relatively low. Cinnabar did not dissolve in the form of nanoparticle. It is postulated that cinnabar could be dissolved in the gastrointestinal tract in various forms of sulfur-containing mercury complexes.

  4. Evaluating the role of re-adsorption of dissolved Hg(2+) during cinnabar dissolution using isotope tracer technique.

    Science.gov (United States)

    Jiang, Ping; Li, Yanbin; Liu, Guangliang; Yang, Guidi; Lagos, Leonel; Yin, Yongguang; Gu, Baohua; Jiang, Guibin; Cai, Yong

    2016-11-05

    Cinnabar dissolution is an important factor controlling mercury (Hg) cycling. Recent studies have suggested the co-occurrence of re-adsorption of the released Hg during the course of cinnabar dissolution. However, there is a lack of feasible techniques that can quantitatively assess the amount of Hg re-adsorbed on cinnabar when investigating cinnabar dissolution. In this study, a new method, based on isotope tracing and dilution techniques, was developed to study the role of Hg re-adsorption in cinnabar dissolution. The developed method includes two key components: (1) accurate measurement of both released and spiked Hg in aqueous phase and (2) estimation of re-adsorbed Hg on cinnabar surface via the reduction in spiked (202)Hg(2+). By adopting the developed method, it was found that the released Hg for trials purged with oxygen could reach several hundred μgL(-1), while no significant cinnabar dissolution was detected under anaerobic condition. Cinnabar dissolution rate when considering Hg re-adsorption was approximately 2 times the value calculated solely with the Hg detected in the aqueous phase. These results suggest that ignoring the Hg re-adsorption process can significantly underestimate the importance of cinnabar dissolution, highlighting the necessity of applying the developed method in future cinnabar dissolution studies.

  5. Cinnabar alteration in archaeological wall paintings: an experimental and theoretical approach

    Science.gov (United States)

    Neiman, Madeleine Kegelman; Balonis, Magdalena; Kakoulli, Ioanna

    2015-11-01

    The red mineral pigment known as cinnabar (HgS) was commonly employed in Roman fresco wall paintings. Fresco artists of the period favored this pigment for its striking red color. However, upon excavation and exposure to air and light, cinnabar-pigmented surfaces recovered from archaeological contexts often proved to be unstable. Mural paintings colored with cinnabar that have been exposed in the open air frequently demonstrate a disfiguring, irreversible darkening of the surface. Traditionally, scholars have attributed this alteration to a light-induced phase change from red α-cinnabar to black β-cinnabar (meta-cinnabar). While this transformation has not been totally excluded, the prevailing view among conservation scientists is that chlorine plays a key role in the darkening process through the formation of light-sensitive mercury chloride compounds, or as a catalyst in the photochemical redox of Hg(II)S into Hg(0) and S(0). Using laboratory-based experiments and thermodynamic modeling, this paper attempts to further clarify the mechanism(s) and kinetics of cinnabar alteration in fresco applications, especially the role of light, humidity, and chlorine ions. Additionally, it explores possible pathways and preventive as well as remedial conservation treatments during or immediately following excavation, to inhibit or retard darkening of cinnabar-pigmented fresco surfaces.

  6. Interferometric phase reconstruction using simplified coherence network

    Science.gov (United States)

    Zhang, Kui; Song, Ruiqing; Wang, Hui; Wu, Di; Wang, Hua

    2016-09-01

    Interferometric time-series analysis techniques, which extend the traditional differential radar interferometry, have demonstrated a strong capability for monitoring ground surface displacement. Such techniques are able to obtain the temporal evolution of ground deformation within millimeter accuracy by using a stack of synthetic aperture radar (SAR) images. In order to minimize decorrelation between stacked SAR images, the phase reconstruction technique has been developed recently. The main idea of this technique is to reform phase observations along a SAR stack by taking advantage of a maximum likelihood estimator which is defined on the coherence matrix estimated from each target. However, the phase value of a coherence matrix element might be considerably biased when its corresponding coherence is low. In this case, it will turn to an outlying sample affecting the corresponding phase reconstruction process. In order to avoid this problem, a new approach is developed in this paper. This approach considers a coherence matrix element to be an arc in a network. A so-called simplified coherence network (SCN) is constructed to decrease the negative impact of outlying samples. Moreover, a pointed iterative strategy is designed to resolve the transformed phase reconstruction problem defined on a SCN. For validation purposes, the proposed method is applied to 29 real SAR images. The results demonstrate that the proposed method has an excellent computational efficiency and could obtain more reliable phase reconstruction solutions compared to the traditional method using phase triangulation algorithm.

  7. Cinnabar Induces Renal Inflammation and Fibrogenesis in Rats

    Directory of Open Access Journals (Sweden)

    Ying Wang

    2015-01-01

    Full Text Available The purpose of this study was to investigate whether cinnabar causes renal inflammation and fibrosis in rats. Rats were dosed orally with cinnabar (1 g/kg/day for 8 weeks or 12 weeks. The control rats were treated with solvent (5% carboxymethylcellulose solution over the same time periods, respectively. Renal mercury (RHg, urinary mercury (UHg, serum creatinine (SCr, urine kidney injury molecule 1 (KIM-1, renal pathology, and renal mediators were examined. At both 8 weeks and 12 weeks, RHg, UHg, and urine KIM-1 were significantly higher in the cinnabar group than in the control group, although SCr was unchanged. Kidney lesions in the cinnabar-treated rats occurred mainly in the tubules and interstitium, including vacuolization, protein casts, infiltration of inflammatory cells, and slight increase in interstitial collagen. In addition, mild mesangial proliferation was observed in glomeruli. Moreover, the expression of inflammatory and fibrogenic mediators was upregulated in the cinnabar group. In conclusion, cinnabar may cause kidney damage due to the accumulation of mercury, and renal inflammation and slight fibrogenesis may occur in rats. In the clinic, the potential risk of renal injury due to the prolonged consumption of cinnabar should be considered even though the agent is relatively nontoxic.

  8. Iterative Reconstruction for Differential Phase Contrast Imaging

    NARCIS (Netherlands)

    Koehler, T.; Brendel, B.; Roessl, E.

    2011-01-01

    Purpose: The purpose of this work is to combine two areas of active research in tomographic x-ray imaging. The first one is the use of iterative reconstruction techniques. The second one is differential phase contrast imaging (DPCI). Method: We derive an SPS type maximum likelihood (ML) reconstructi

  9. 4D Lung Reconstruction with Phase Optimization

    DEFF Research Database (Denmark)

    Lyksborg, Mark; Paulsen, Rasmus; Brink, Carsten;

    2009-01-01

    This paper investigates and demonstrates a 4D lung CT reconstruction/registration method which results in a complete volumetric model of the lung that deforms according to a respiratory motion field. The motion field is estimated iteratively between all available slice samples and a reference vol...... than using an optimization which does not correct for phase errors. Knowing how the lung and any tumors located within the lung deforms is relevant in planning the treatment of lung cancer.......This paper investigates and demonstrates a 4D lung CT reconstruction/registration method which results in a complete volumetric model of the lung that deforms according to a respiratory motion field. The motion field is estimated iteratively between all available slice samples and a reference...

  10. Reconstruction methods for phase-contrast tomography

    Energy Technology Data Exchange (ETDEWEB)

    Raven, C.

    1997-02-01

    Phase contrast imaging with coherent x-rays can be distinguished in outline imaging and holography, depending on the wavelength {lambda}, the object size d and the object-to-detector distance r. When r << d{sup 2}{lambda}, phase contrast occurs only in regions where the refractive index fastly changes, i.e. at interfaces and edges in the sample. With increasing object-to-detector distance we come in the area of holographic imaging. The image contrast outside the shadow region of the object is due to interference of the direct, undiffracted beam and a beam diffracted by the object, or, in terms of holography, the interference of a reference wave with the object wave. Both, outline imaging and holography, offer the possibility to obtain three dimensional information of the sample in conjunction with a tomographic technique. But the data treatment and the kind of information one can obtain from the reconstruction is different.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  12. Phase Transition in Distance-Based Phylogeny Reconstruction

    CERN Document Server

    Roch, Sebastien

    2011-01-01

    We introduce a new distance-based phylogeny reconstruction technique which provably achieves, at sufficiently short branch lengths, a logarithmic sequence-length requirement---improving significantly over previous polynomial bounds for distance-based methods and matching existing results for general methods. The technique is based on an averaging procedure that implicitly reconstructs ancestral sequences. In the same token, we extend previous results on phase transitions in phylogeny reconstruction to general time-reversible models. More precisely, we show that in the so-called Kesten-Stigum zone (roughly, a region of the parameter space where ancestral sequences are well approximated by "linear combinations" of the observed sequences) sequences of length $O(\\log n)$ suffice for reconstruction when branch lengths are discretized. Here $n$ is the number of extant species. Our results challenge, to some extent, the conventional wisdom that estimates of evolutionary distances alone carry significantly less infor...

  13. Cinnabar, arsenian pyrite and thallium-enrichment in active shallow submarine hydrothermal vents at Paleochori Bay, Milos Island, Greece

    Science.gov (United States)

    Kati, Marianna; Voudouris, Panagiotis; Valsami-Jones, Eugenia; Magganas, Andreas; Baltatzis, Emmanouil; Kanellopoulos, Christos; Mavrogonatos, Constantinos

    2015-04-01

    We herein report the discovery of active cinnabar-depositing hydrothermal vents in a submarine setting at Paleochori Bay, within the offshore southeastern extension of the Milos Island Geothermal Field, South Aegean Active Volcanic Arc. Active, low temperature (up to 115 °C) hydrothermal venting through volcaniclastic material has led to a varied assemblage of sulfide and alteration mineral phases in an area of approximately 1 km2. Our samples recovered from Paleochori Bay are hydrothermal edifices composed of volcaniclastic detrital material cemented by pyrite, or pure sulfide (mainly massive pyrite) mounts. Besides pyrite and minor marcasite, the hydrothermal minerals include cinnabar, amorphous silica, hydrous ferric oxides, carbonates (aragonite and calcite), alunite-jarosite solid solution and Sr-rich barite. Among others, growth textures, sieve-textured pyrite associated with barite, alunite-jarosite solid solution and hydrous ferric oxides rims colloform-banded pyrite layers. Overgrowths of arsenian pyrite layers (up to 3.2 wt. % As and/or up to 1.1 wt. % Mn) onto As-free pyrite indicate fluctuation in As content of the hydrothermal fluid. Mercury, in the form of cinnabar, occurs in up to 5 μm grains within arsenian pyrite layers, usually forming distinct cinnabar-enriched micro-layers. Hydrothermal Sr-rich barite (barite-celestine solid solution), pseudocubic alunite-jarosite solid solution and Mn- and Sr-enriched carbonates occur in various amounts and closely associated with pyrite and/or hydrous ferric oxides. Thallium-bearing sulfides and/or sulfosalts were not detected during our study; however, hydrous ferric oxides show thallium content of up to 0.5 wt. % Tl. The following scenarios may have played a role in pyrite precipitation at Paleochori: (a) H2S originally dissolved in the deep fluid but separated upon boiling could have reacted with oxygenated seawater under production of sulphuric acid, thus causing leaching and dissolution of primary iron

  14. On simulated annealing phase transitions in phylogeny reconstruction.

    Science.gov (United States)

    Strobl, Maximilian A R; Barker, Daniel

    2016-08-01

    Phylogeny reconstruction with global criteria is NP-complete or NP-hard, hence in general requires a heuristic search. We investigate the powerful, physically inspired, general-purpose heuristic simulated annealing, applied to phylogeny reconstruction. Simulated annealing mimics the physical process of annealing, where a liquid is gently cooled to form a crystal. During the search, periods of elevated specific heat occur, analogous to physical phase transitions. These simulated annealing phase transitions play a crucial role in the outcome of the search. Nevertheless, they have received comparably little attention, for phylogeny or other optimisation problems. We analyse simulated annealing phase transitions during searches for the optimal phylogenetic tree for 34 real-world multiple alignments. In the same way in which melting temperatures differ between materials, we observe distinct specific heat profiles for each input file. We propose this reflects differences in the search landscape and can serve as a measure for problem difficulty and for suitability of the algorithm's parameters. We discuss application in algorithmic optimisation and as a diagnostic to assess parameterisation before computationally costly, large phylogeny reconstructions are launched. Whilst the focus here lies on phylogeny reconstruction under maximum parsimony, it is plausible that our results are more widely applicable to optimisation procedures in science and industry.

  15. Dynamic characteristics of an NC table with phase space reconstruction

    Institute of Scientific and Technical Information of China (English)

    Linhong WANG; Bo WU; Runsheng DU; Shuzi YANG

    2009-01-01

    The dynamic properties of a numerical control (NC) table directly interfere with the accuracy and surface quality of work pieces machined by a computer numerical control (CNC) machine. Phase space reconstruction is an effective approach for researching dynamic behaviors of a system with measured time series. Based on the theory and method for phase space reconstruction, the correlation dimension, maximum Lyapunov exponent, and dynamic time series measured from the NC table were analyzed. The characteristic quantities such as the power spectrum, phase trajectories, correlation dimension, and maximum Lyapunov exponent are extracted from the measured time series. The chaotic characteristic of the dynamic properties of the NC table is revealed via various approaches.Therefore, an NC table is a nonlinear dynamic system. This research establishes a basis for dynamic system discrimi-nation of a CNC machine.

  16. Position Reconstruction in a Dual Phase Xenon Scintillation Detector

    CERN Document Server

    Solovov, V N; Akimov, D Yu; Araújo, H M; Barnes, E J; Burenkov, A A; Chepel, V; Currie, A; DeViveiros, L; Edwards, B; Ghag, C; Hollingsworth, A; Horn, M; Kalmus, G E; Kobyakin, A S; Kovalenko, A G; Lebedenko, V N; Lindote, A; Lopes, M I; Lüscher, R; Majewski, P; Murphy, A St J; Neves, F; Paling, S M; da Cunha, J Pinto; Preece, R; Quenby, J J; Reichhart, L; Scovell, P R; Silva, C; Smith, N J T; Smith, P F; Stekhanov, V N; Sumner, T J; Thorne, C; Walker, R J

    2011-01-01

    We studied the application of statistical reconstruction algorithms, namely maximum likelihood and least squares methods, to the problem of event reconstruction in a dual phase liquid xenon detector. An iterative method was developed for in-situ reconstruction of the PMT light response functions from calibration data taken with an uncollimated gamma-ray source. Using the techniques described, the performance of the ZEPLIN-III dark matter detector was studied for 122 keV gamma-rays. For the inner part of the detector (R<100 mm), spatial resolutions of 13 mm and 1.6 mm FWHM were measured in the horizontal plane for primary and secondary scintillation, respectively. An energy resolution of 8.1% FWHM was achieved at that energy. The possibility of using this technique for improving performance and reducing cost of scintillation cameras for medical applications is currently under study.

  17. Phase 1 of the Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    1991-08-01

    The work described in this report was prompted by the public's concern about potential effect from the radioactive materials released from the Hanford Site. The Hanford Environmental Dose Reconstruction (HEDR) Project was established to estimate radiation dose the public might have received from the Hanford Site since 1944, when facilities began operating. Phase 1 of the HEDR Project is a pilot'' or demonstration'' phase. The objectives of this initial phase were to determine whether enough historical information could be found or reconstructed to be used for dose estimation and develop and test conceptual and computational models for calculating credible dose estimates. Preliminary estimates of radiation doses were produced in Phase 1 because they are needed to achieve these objectives. The reader is cautioned that the dose estimates provided in this and other Phase 1 HEDR reports are preliminary. As the HEDR Project continues, the dose estimates will change for at least three reasons: more complete input information for models will be developed; the models themselves will be refined; and the size and shape of the geographic study area will change. This is one of three draft reports that summarize the first phase of the four-phased HEDR Project. This, the Summary Report, is directed to readers who want a general understanding of the Phase 1 work and preliminary dose estimates. The two other reports -- the Air Pathway Report and the Columbia River Pathway Report -- are for readers who understand the radiation dose assessment process and want to see more technical detail. Detailed descriptions of the dose reconstruction process are available in more than 20 supporting reports listed in Appendix A. 32 refs., 46 figs.

  18. Cinnabar-Induced Subchronic Renal Injury Is Associated with Increased Apoptosis in Rats

    Directory of Open Access Journals (Sweden)

    Ying Wang

    2015-01-01

    Full Text Available The aim of this study was to explore the role of apoptosis in cinnabar-induced renal injury in rats. To test this role, rats were dosed orally with cinnabar (1 g/kg/day for 8 weeks or 12 weeks, and the control rats were treated with 5% carboxymethylcellulose solution. Levels of urinary mercury (UHg, renal mercury (RHg, serum creatinine (SCr, and urine kidney injury molecule 1 (KIM-1 were assessed, and renal pathology was analyzed. Apoptotic cells were identified and the apoptotic index was calculated. A rat antibody array was used to analyze expression of cytokines associated with apoptosis. Results from these analyses showed that UHg, RHg, and urine KIM-1, but not SCr, levels were significantly increased in cinnabar-treated rats. Renal pathological changes in cinnabar-treated rats included vacuolization of tubular cells, formation of protein casts, infiltration of inflammatory cells, and increase in the number of apoptotic tubular cells. In comparison to the control group, expression of FasL, Fas, TNF-α, TRAIL, activin A, and adiponectin was upregulated in the cinnabar-treated group. Collectively, our results suggest that prolonged use of cinnabar results in kidney damage due to accumulation of mercury and that the underlying mechanism involves apoptosis of tubular cells via a death receptor-mediated pathway.

  19. Quality Study on Cinnabar-analysis of Dyeing Status for Cinnabar%朱砂染色现状分析

    Institute of Scientific and Technical Information of China (English)

    邢潇; 刘治民; 徐彤彤; 谷妲; 梁玉冰; 张鑫; 杨建龙

    2016-01-01

    目的:分析朱砂药材及饮片染色现状,为朱砂药材及饮片的品质和临床安全应用提供参考依据。方法:采用薄层色谱法(TLC)对药材和饮片中苋菜红、胭脂红、赤藓红、酸性红73、808猩红、靛玉红进行定性鉴别。采用高效液相色谱-质谱联用法(HPLC-MS)检测药材及饮片中的808猩红。HPLC条件:色谱柱为Acquity UPLC BEH C18,流动相为乙腈-0.1%甲酸(70∶30,V/V),流速为0.3 ml/min,检测波长为520 nm;MS条件:离子源为电喷雾离子源,扫描方式为正离子扫描,检测方式为全扫描二级质谱,雾化器压力为30 psi,干燥气为氮气,离子喷雾电压为4000 V,碰撞能为30 V,进样量为5μl。采用容量法测定药材及饮片中硫化汞(HgS)的含量。结果:苋菜红、胭脂红、赤藓红、酸性红73、808猩红、靛玉红的TLC斑点清晰,分离良好。18批样品中有4批808猩红染色,有6批HgS含量不达标(其中3批同时为808猩红染色)。结论:目前市场中流通的朱砂药材及饮片存在染色掺杂和HgS含量不达标等质量问题,应引起重视。%OBJECTIVE:To analyze the dyeing status of cinnabar and its pieces,and provide reference for its quality clinical safetey appicaton. METHODS:TLC was used for the qualitative identification of amaranth,carmine,erythrosine,acid red 73, 808 udan and indirubin. HPLC-MS was used to detect the 808 udan :HPLC conditions were as follows,column was Acquity UPLC BEH C18 with mobile phase of cetonitrile-0.1% formic acid(70∶30,V/V)at a flow rate of 0.3 ml/min,the detection wave-length was 520 nm;MS conditions were as follows,ion source was electrospray ionization source,scanning mode was positive ion scanning with full scanning tandem mass spectrometry,nebulizer pressure was 30 psi,drying gas was nitrogen,ion spray voltage was 4 000 V,collision energy was 30 V,and the injection volume was 5 μl. The volumetric method was used

  20. Enhanced wavefront reconstruction by random phase modulation with a phase diffuser

    DEFF Research Database (Denmark)

    Almoro, Percival F; Pedrini, Giancarlo; Gundu, Phanindra Narayan

    2011-01-01

    A phase retrieval technique for enhanced wavefront reconstruction using random phase modulation and a phase diffuser is proposed. The speckle field generated is sampled at multiple axially displaced planes and the speckle patterns are used in an iterative algorithm based on the optical wave...... of the diffusely scattered beam. The use of demagnification optics will also allow the investigations of relatively large objects. In the second setup, a transparent object is illuminated using a wavefront with random phase and constant amplitude by positioning the phase diffuser close to the object. The benefit...... of phase-only modulation is the increased resolution of the phase structures of the transparent test objects....

  1. Prediction of Tropical Rainfall by Local Phase Space Reconstruction.

    Science.gov (United States)

    Waelbroeck, H.; López-Pea, R.; Morales, T.; Zertuche, F.

    1994-11-01

    The authors propose a weather prediction model based on a local reconstruction of the dynamics in phase space, using an 11-year dataset from Tlaxcala, Mexico. A vector in phase space corresponds to T consecutive days of data; the best predictions are found for T = 14. The prediction for the next day, x0 fL(x0), is based on a local reconstruction of the dynamical map f in an ball centered at x0. The high dimensionality of the phase space implies a large optimal value of , so that the number of points in an ball is sufficient to reconstruct the local map. The local approximation fL f is therefore not very good and the prediction skill drops off quickly at first, with a timescale of 2 days. On the other hand, the authors find useful skill in the prediction of 10-day rainfall accumulations, which reflects the persistence of weather patterns. The mean-squared error in the prediction of the rainfall anomaly for the year 1992 was 64% of the variance, and the early beginning of the rain season was correctly predicted.

  2. Reconstruction of N-acetyltransferase 2 haplotypes using PHASE.

    Science.gov (United States)

    Golka, Klaus; Blaszkewicz, Meinolf; Samimi, Mirabutaleb; Bolt, Hermann M; Selinski, Silvia

    2008-04-01

    The genotyping of N-acetyltransferase 2 (NAT2) by PCR/RFLP methods yields in a considerable percentage ambiguous results. To resolve this methodical problem a statistical approach was applied. PHASE v2.1.1, a statistical program for haplotype reconstruction was used to estimate haplotype pairs from NAT2 genotyping data, obtained by the analysis of seven single nucleotide polymorphisms relevant for Caucasians. In 1,011 out of 2,921 (35%) subjects the haplotype pairs were clearcut by the PCR/RFLP data only. For the majority of the data the applied method resulted in a multiplicity (2-4) of possible haplotype pairs. Haplotype reconstruction using PHASE v2.1.1 cleared this ambiguity in all cases but one, where an alternative haplotype pair was considered with a probability of 0.029. The estimation of the NAT2 haplotype is important because the assignment of the NAT2 alleles *12A, *12B, *12C or *13 to the rapid or slow NAT2 genotype has been discussed controversially. A clear assignment is indispensable in surveys of human bladder cancer caused by aromatic amine exposures. In conclusion, PHASE v2.1.1 software allowed an unambiguous haplotype reconstruction in 2,920 of 2,921 cases (>99.9%).

  3. A Phase Current Reconstruction Approach for Three-Phase Permanent-Magnet Synchronous Motor Drive

    Directory of Open Access Journals (Sweden)

    Hao Yan

    2016-10-01

    Full Text Available Three-phase permanent-magnet synchronous motors (PMSMs are widely used in renewable energy applications such as wind power generation, tidal energy and electric vehicles owing to their merits such as high efficiency, high precision and high reliability. To reduce the cost and volume of the drive system, techniques of reconstructing three-phase current using a single current sensor have been reported for three-phase alternating current (AC control system using the power converts. In existing studies, the reconstruction precision is largely influenced by reconstructing dead zones on the Space Vector Pulse Width Modulation (SVPWM plane, which requires other algorithms to compensate either by modifying PWM modulation or by phase-shifting of the PWM signal. In this paper, a novel extended phase current reconstruction approach for PMSM drive is proposed. Six novel installation positions are obtained by analyzing the sampling results of the current paths between each two power switches. By arranging the single current sensor at these positions, the single current sensor is sampled during zero voltage vectors (ZVV without modifying the PWM signals. This proposed method can reconstruct the three-phase currents without any complex algorithms and is available in the sector boundary region and low modulation region. Finally, this method is validated by experiments.

  4. Phase reconstruction from intensity measurements in linear systems.

    Science.gov (United States)

    Bastiaans, Martin J; Wolf, Kurt Bernardo

    2003-06-01

    The phase of a signal at a plane is reconstructed from the intensity profiles at two close parallel screens connected by a small abcd canonical transform; this applies to propagation along harmonic and repulsive fibers and in free media. We analyze the relationship between the local spatial frequency (the signal phase derivative) and the derivative of the squared modulus of the signal under a one-parameter canonical transform with respect to the parameter. We thus generalize to all linear systems the results that have been obtained separately for Fresnel and fractional Fourier transforms.

  5. Study of Phase Reconstruction Techniques applied to Smith-Purcell Radiation Measurements

    CERN Document Server

    Delerue, Nicolas; Bezshyyko, Oleg; Khodnevych, Vitalii

    2015-01-01

    Measurements of coherent radiation at accelerators typically give the absolute value of the beam profile Fourier transform but not its phase. Phase reconstruction techniques such as Hilbert transform or Kramers Kronig reconstruction are used to recover such phase. We report a study of the performances of these methods and how to optimize the reconstructed profiles.

  6. Study of Phase Reconstruction Techniques applied to Smith-Purcell Radiation Measurements

    CERN Document Server

    Delerue, Nicolas; Vieille-Grosjean, Mélissa; Bezshyyko, Oleg; Khodnevych, Vitalii

    2014-01-01

    Measurements of coherent radiation at accelerators typically give the absolute value of the beam profile Fourier transform but not its phase. Phase reconstruction techniques such as Hilbert transform or Kramers Kronig reconstruction are used to recover such phase. We report a study of the performances of these methods and how to optimize the reconstructed profiles.

  7. Phase 1 of the Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-20

    For more than 40 years, the US government made plutonium for nuclear weapons at the Hanford Site in southeastern Washington State. Radioactive materials were released to both the air and water from Hanford. People could have been exposed to these materials, called radionuclides. The Hanford Environmental Dose Reconstruction (HEDR) Project is a multi-year scientific study to estimate the radiation doses the public may have received as a results of these releases. The study began in 1988. During the first phase, scientists began to develop and test methods for reconstructing the radiation doses. To do this, scientists found or reconstructed information about the amount and type of radionuclides that were released from Hadford facilities, where they traveled in environment, and how they reached people. Information about the people who could have been exposed was also found or reconstructed. Scientists then developed a computer model that can estimate doses from radiation exposure received many years ago. All the information that had been gathered was fed into the computer model. Then scientists did a test run'' to see whether the model was working properly. As part of its test run,'' scientists asked the computer model to generate two types of preliminary results: amounts of radionuclides in the environment (air, soil, pasture grass, food, and milk) and preliminary doses people could have received from all the routes of radiation exposure, called exposure pathways. Preliminary dose estimates were made for categories of people who shared certain characteristics and for the Phase 1 population as a whole. 26 refs., 48 figs.

  8. Linear Phase Perfect Reconstruction Filters and Wavelets with Even Symmetry

    CERN Document Server

    Monzon, Lucas

    2011-01-01

    Perfect reconstruction filter banks can be used to generate a variety of wavelet bases. Using IIR linear phase filters one can obtain symmetry properties for the wavelet and scaling functions. In this paper we describe all possible IIR linear phase filters generating symmetric wavelets with any prescribed number of vanishing moments. In analogy with the well known FIR case, we construct and study a new family of wavelets obtained by considering maximal number of vanishing moments for each fixed order of the IIR filter. Explicit expressions for the coefficients of numerator, denominator, zeroes, and poles are presented. This new parameterization allows one to design linear phase quadrature mirror filters with many other properties of interest such as filters that have any preassigned set of zeroes in the stopband or that satisfy an almost interpolating property. Using Beylkin's approach, it is indicated how to implement these IIR filters not as recursive filters but as FIR filters.

  9. Phase Closure Image Reconstruction for Future VLTI Instrumentation

    CERN Document Server

    Filho, Mercedes E; Garcia, Paulo; Duvert, Gilles; Duchene, Gaspard; Thiebaut, Eric; Young, John; Absil, Olivier; Berger, Jean-Phillipe; Beckert, Thomas; Hoenig, Sebastian; Schertl, Dieter; Weigelt, Gerd; Testi, Leonardo; Tatuli, Eric; Borkowski, Virginie; de Becker, Michael; Surdej, Jean; Aringer, Bernard; Hron, Joseph; Lebzelter, Thomas; Chiavassa, Andrea; Corradi, Romano; Harries, Tim

    2008-01-01

    Classically, optical and near-infrared interferometry have relied on closure phase techniques to produce images. Such techniques allow us to achieve modest dynamic ranges. In order to test the feasibility of next generation optical interferometers in the context of the VLTI-spectro-imager (VSI), we have embarked on a study of image reconstruction and analysis. Our main aim was to test the influence of the number of telescopes, observing nights and distribution of the visibility points on the quality of the reconstructed images. Our results show that observations using six Auxiliary Telescopes (ATs) during one complete night yield the best results in general and is critical in most science cases; the number of telescopes is the determining factor in the image reconstruction outcome. In terms of imaging capabilities, an optical, six telescope VLTI-type configuration and ~200 meter baseline will achieve 4 mas spatial resolution, which is comparable to ALMA and almost 50 times better than JWST will achieve at 2.2...

  10. Simultaneous maximum-likelihood reconstruction for x-ray grating based phase-contrast tomography avoiding intermediate phase retrieval

    CERN Document Server

    Ritter, André; Durst, Jürgen; Gödel, Karl; Haas, Wilhelm; Michel, Thilo; Rieger, Jens; Weber, Thomas; Wucherer, Lukas; Anton, Gisela

    2013-01-01

    Phase-wrapping artifacts, statistical image noise and the need for a minimum amount of phase steps per projection limit the practicability of x-ray grating based phase-contrast tomography, when using filtered back projection reconstruction. For conventional x-ray computed tomography, the use of statistical iterative reconstruction algorithms has successfully reduced artifacts and statistical issues. In this work, an iterative reconstruction method for grating based phase-contrast tomography is presented. The method avoids the intermediate retrieval of absorption, differential phase and dark field projections. It directly reconstructs tomographic cross sections from phase stepping projections by the use of a forward projecting imaging model and an appropriate likelihood function. The likelihood function is then maximized with an iterative algorithm. The presented method is tested with tomographic data obtained through a wave field simulation of grating based phase-contrast tomography. The reconstruction result...

  11. Optical correlation algorithm for reconstructing phase skeleton of complex optical fields for solving the phase problem

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Gorsky, M. P.; Hanson, Steen Grüner;

    2014-01-01

    We propose an optical correlation algorithm illustrating a new general method for reconstructing the phase skeleton of complex optical fields from the measured two-dimensional intensity distribution. The core of the algorithm consists in locating the saddle points of the intensity distribution an...... and connecting such points into nets by the lines of intensity gradient that are closely associated with the equi-phase lines of the field. This algorithm provides a new partial solution to the inverse problem in optics commonly referred to as the phase problem....

  12. The holographic reconstructing algorithm and its error analysis about phase-shifting phase measurement

    Institute of Scientific and Technical Information of China (English)

    LU Xiaoxu; ZHONG Liyun; ZHANG Yimo

    2007-01-01

    Phase-shifting measurement and its error estimation method were studied according to the holographic principle.A function of synchronous superposition of object complex amplitude reconstructed from N-step phase-shifting through one integral period (N-step phase-shifting function for short) was proposed.In N-step phase-shifting measurement,the interferograms are seen as a series of in-line holograms and the reference beam is an ideal parallel-plane wave.So the N-step phase-shifting function can be obtained by multiplying the interferogram by the original referencc wave.In ideal conditions.the proposed method is a kind of synchronous superposition algorithm in which the complex amplitude is separated,measured and superposed.When error exists in measurement,the result of the N-step phase-shifting function is the optimal expected value of the least-squares fitting method.In the above method,the N+1-step phase-shifting function can be obtained from the N-step phase-shifting function.It shows that the N-step phase-shifting function can be separated into two parts:the ideal N-step phase-shifting function and its errors.The phase-shifting errors in N-steps phase-shifting phase measurement can be treated the same as the relative errors of amplitude and intensity under the understanding of the N+1-step phase-shifting function.The difficulties of the error estimation in phase-shifting phase measurement were restricted by this error estimation method.Meanwhile,the maximum error estimation method of phase-shifting phase measurement and its formula were proposed.

  13. Comparison of pulse phase and thermographic signal reconstruction processing methods

    Science.gov (United States)

    Oswald-Tranta, Beata; Shepard, Steven M.

    2013-05-01

    Active thermography data for nondestructive testing has traditionally been evaluated by either visual or numerical identification of anomalous surface temperature contrast in the IR image sequence obtained as the target sample cools in response to thermal stimulation. However, in recent years, it has been demonstrated that considerably more information about the subsurface condition of a sample can be obtained by evaluating the time history of each pixel independently. In this paper, we evaluate the capabilities of two such analysis techniques, Pulse Phase Thermography (PPT) and Thermographic Signal Reconstruction (TSR) using induction and optical flash excitation. Data sequences from optical pulse and scanned induction heating are analyzed with both methods. Results are evaluated in terms of signal-tobackground ratio for a given subsurface feature. In addition to the experimental data, we present finite element simulation models with varying flaw diameter and depth, and discuss size measurement accuracy and the effect of noise on detection limits and sensitivity for both methods.

  14. Project 8 Phase II: Improved beta decay electrons reconstruction

    Science.gov (United States)

    Guigue, Mathieu; Project 8 Collaboration

    2017-01-01

    The Project 8 collaboration aims to measure the absolute neutrino mass scale using a cyclotron radiation emission spectroscopy technique on the beta decays of tritium. The second phase of the project will measure a differential spectrum of tritium beta decays and extract the tritium endpoint value with an eV or sub-eV scale precision. Monoenergetic electrons emitted by gaseous 83mKr atoms can be used to determine the coefficient between the cyclotron frequency and the electron energy and to optimize the instrument configuration for the tritium measurement. We present the progress on the processing of the electron cyclotron radiation signal to reconstruct the beta decay spectrum of krypton and tritium.

  15. Single Shot Digital Holography Using Iterative Reconstruction with Alternating Updates of Amplitude and Phase

    CERN Document Server

    Lee, Dennis J; Weiner, Andrew M

    2016-01-01

    We present an image recovery approach to improve amplitude and phase reconstruction from single shot digital holograms, using iterative reconstruction with alternating updates. This approach allows the flexibility to apply different priors to amplitude and phase, improves phase reconstruction in image areas with low amplitudes, and does not require phase unwrapping for regularization. Phantom simulations and experimental measurements of a grating sample both demonstrate that the proposed method helps to reduce noise and resolve finer features. The improved image reconstruction from this technique will benefit the many applications of digital holography.

  16. A method for phase reconstruction in optical three-dimensional shape measurement

    Institute of Scientific and Technical Information of China (English)

    Qiao Nao-Sheng; He Zhi

    2012-01-01

    In optical three-dimensional shape measurement,a method of improving the measurement precision for phase reconstruction without phase unwrapping is analyzed in detail.Intensities of any five consecutive pixels that lie in the x-axis direction of the phase domain are given.Partial derivatives of the phase function in the x- and y-axis directions are obtained with a phase-shifting mechanism,the origin of which is analysed.Furthermore,to avoid phase unwrapping in the phase reconstruction,we derive the gradient of the phase function and perform a two-dimensional integral along the x- and y-axis directions.The reconstructed phase can be obtained directly by performing numerical integration,and thus it is of great convenience for phase reconstruction.Finally,the results of numerical simulations and practical experiments verify the correctness of the proposed method.

  17. [Dissolution, absorption and bioaccumulation in gastrointestinal tract of mercury in HgS-containing traditional medicines Cinnabar and Zuotai].

    Science.gov (United States)

    Zheng, Zhi-yuan; Li, Cen; Zhang, Ming; Yang, Hong-xia; Geng, Lu-jing; Li, Lin-shuai; Du, Yu-zhi; Wei, Li-xin

    2015-06-01

    α-HgS is the main component of traditional Chinese medicine cinnabar, while β-HgS is the main component of Tibetan medicine Zuotai. However, there was no comparative study on the dissolution and absorption in gastrointestinal tract and bioaccumulation in organs of mercury in Cinnabar, Zuotai, α-HgS and β-HgS. In this study, the dissolution process of the four compounds in the human gastrointestinal tract was simulated to determine the mercury dissolutions and compare the mercury dissolution of different medicines and the dissolution-promoting capacity of different solutions. To explore the absorption and bioaccumulation of cinnabar and Zuotai in organisms, mice were orally administered with clinical equivalent doses cinnabar and Zuotai. Meanwhile, a group of mice was given α-HgS and β-HgS with the equivalent mercury with cinnabar, while another group was given β-HgS and HgCl2 with the equivalent mercury with Zuotai. The mercury absorption and bioaccumulation capacities of different medicines in mice and their mercury bioaccumulation in different tissues and organs were compared. The experimental results showed a high mercury dissolutions of Zuotai in artificial gastrointestinal fluid, which was followed by β-HgS, cinnabar and α-HgS. As for the mercury absorption and bioaccumulation in mice, HgCl2 was the highest, β-HgS was the next, and a-HgS was slightly higher than cinnabar. The organs with the mercury bioaccumulation from high to low were kidney, liver and brain. This study is close to clinical practices and can provide reference for the clinical safe medication as well as a study model for the safety evaluation on heavy metal-containing medicines by observing the mercury dissolution, absorption, distribution and accumulation of mercury-containing medicines cinnabar and zuotai.

  18. Chronic mercury exposure in Late Neolithic/Chalcolithic populations in Portugal from the cultural use of cinnabar

    Science.gov (United States)

    Emslie, Steven D.; Brasso, Rebecka; Patterson, William P.; Carlos Valera, António; McKenzie, Ashley; Maria Silva, Ana; Gleason, James D.; Blum, Joel D.

    2015-10-01

    Cinnabar is a natural mercury sulfide (HgS) mineral of volcanic or hydrothermal origin that is found worldwide. It has been mined prehistorically and historically in China, Japan, Europe, and the Americas to extract metallic mercury (Hg0) for use in metallurgy, as a medicinal, a preservative, and as a red pigment for body paint and ceramics. Processing cinnabar via combustion releases Hg0 vapor that can be toxic if inhaled. Mercury from cinnabar can also be absorbed through the gut and skin, where it can accumulate in organs and bone. Here, we report moderate to high levels of total mercury (THg) in human bone from three Late Neolithic/Chalcolithic (5400-4100 B.P.) sites in southern Portugal that were likely caused by cultural use of cinnabar. We use light stable isotope and Hg stable isotope tracking to test three hypotheses on the origin of mercury in this prehistoric human bone. We traced Hg in two individuals to cinnabar deposits near Almadén, Spain, and conclude that use of this mineral likely caused mild to severe mercury poisoning in the prehistoric population. Our methods have applications to bioarchaeological investigations worldwide, and for tracking trade routes and mobility of prehistoric populations where cinnabar use is documented.

  19. Bacterial Influence on the Solubility of Cinnabar and Metacinnabar at New Idria, CA

    Science.gov (United States)

    Jew, A. D.; Rytuba, J. J.; Spormann, A. M.; Brown, G. E.

    2007-12-01

    Mercury in the forms of cinnabar (α-HgS) and metacinnabar (β-HgS) is generally considered to be unreactive and of little environmental concern. To determine if this current belief is valid, a consortium of bacteria (including a Thiomonas intermedia-like bacterium) was taken from the acid mine drainage (AMD) pond at the New Idria Hg Mine, San Benito Co., CA, and inoculated into filter-sterilized AMD pond water (pH = 4) containing either ground cinnabar or metacinnabar crystals (Minteq with AMD pond water chemistry determined by ICP-MS and total mercury and total sulfide analyses. These calculations give an equilibrium solubility product for the dissolution of HgS up to 25 orders of magnitude higher than HgS under standard conditions. When compared to calculations by Paquette et al., 1997 and Benoit et al., 1999, the bacterial consortium at New Idria causes an increase in the pK for all reported reactions including H+, HS-, and H2S of 11-13 orders of magnitude. These results indicate that the biofilm consortium at the New Idria AMD pond has a profound effect on the solubility of cinnabar and metacinnabar, suggesting that a reassessment of HgS stability in aerobic AMD environments is needed.

  20. Mercury emission and dispersion models from soils contaminated by cinnabar mining and metallurgy.

    Science.gov (United States)

    Llanos, Willians; Kocman, David; Higueras, Pablo; Horvat, Milena

    2011-12-01

    The laboratory flux measurement system (LFMS) and dispersion models were used to investigate the kinetics of mercury emission flux (MEF) from contaminated soils. Representative soil samples with respect to total Hg concentration (26-9770 μg g(-1)) surrounding a decommissioned mercury-mining area (Las Cuevas Mine), and a former mercury smelter (Cerco Metalúrgico de Almadenejos), in the Almadén mercury mining district (South Central Spain), were collected. Altogether, 14 samples were analyzed to determine the variation in mercury emission flux (MEF) versus distance from the sources, regulating two major environmental parameters comprising soil temperature and solar radiation. In addition, the fraction of the water-soluble mercury in these samples was determined in order to assess how MEF from soil is related to the mercury in the aqueous soil phase. Measured MEFs ranged from less than 140 to over 10,000 ng m(-2) h(-1), with the highest emissions from contaminated soils adjacent to point sources. A significant decrease of MEF was then observed with increasing distance from these sites. Strong positive effects of both temperature and solar radiation on MEF was observed. Moreover, MEF was found to occur more easily in soils with higher proportions of soluble mercury compared to soils where cinnabar prevails. Based on the calculated Hg emission rates and with the support of geographical information system (GIS) tools and ISC AERMOD software, dispersion models for atmospheric mercury were implemented. In this way, the gaseous mercury plume generated by the soil-originated emissions at different seasons was modeled. Modeling efforts revealed that much higher emissions and larger mercury plumes are generated in dry and warm periods (summer), while the plume is smaller and associated with lower concentrations of atmospheric mercury during colder periods with higher wind activity (fall). Based on the calculated emissions and the model implementation, yearly emissions from

  1. Phase contrast X-ray microtomography of the Rhodnius prolixus head: Comparison of direct reconstruction and phase retrieval approach

    Science.gov (United States)

    Almeida, A. P.; Braz, D.; Nogueira, L. P.; Colaço, M. V.; Soares, J.; Cardoso, S. C.; Garcia, E. S.; Azambuja, P.; Gonzalez, M. S.; Mohammadi, S.; Tromba, G.; Barroso, R. C.

    2014-02-01

    We have used phase-contrast X-ray microtomography (PPC-μCT) to study the head of the blood-feeding bug, Rhodnius prolixus, which is one of the most important insect vector of Trypanosoma cruzi, ethiologic agent of Chagas disease in Latin America. Images reconstructed from phase-retrieved projections processed by ANKA phase are compared to those obtained through direct tomographic reconstruction of the flat-field-corrected transmission radiographs. It should be noted that the relative locations of the important morphological internal structures are observable with a precision that is difficult to obtain without the phase retrieval approach.

  2. Incomplete Phase Space Reconstruction Method Based on Subspace Adaptive Evolution Approximation

    Directory of Open Access Journals (Sweden)

    Tai-fu Li

    2013-01-01

    Full Text Available The chaotic time series can be expanded to the multidimensional space by phase space reconstruction, in order to reconstruct the dynamic characteristics of the original system. It is difficult to obtain complete phase space for chaotic time series, as a result of the inconsistency of phase space reconstruction. This paper presents an idea of subspace approximation. The chaotic time series prediction based on the phase space reconstruction can be considered as the subspace approximation problem in different neighborhood at different time. The common static neural network approximation is suitable for a trained neighborhood, but it cannot ensure its generalization performance in other untrained neighborhood. The subspace approximation of neural network based on the nonlinear extended Kalman filtering (EKF is a dynamic evolution approximation from one neighborhood to another. Therefore, in view of incomplete phase space, due to the chaos phase space reconstruction, we put forward subspace adaptive evolution approximation method based on nonlinear Kalman filtering. This method is verified by multiple sets of wind speed prediction experiments in Wulong city, and the results demonstrate that it possesses higher chaotic prediction accuracy.

  3. Application study of transport intensity equation in quantitative phase reconstruction

    Science.gov (United States)

    Song, Xiaojun; Cheng, Wei; Wei, Chunjuan; Xue, Liang; Liu, Weijing; Bai, Baodan; Chu, Fenghong

    2016-10-01

    In order to improve detection speed and accuracy of biological cells, a quantitative non-interference optical phase recovery method is proposed in commercial microscope, taking the red blood cells as the classical phase objects. Three bright field micrographs were collected in the experiment. Utilizing the transport intensity equation (TIE), the quantitative phase distributions of red blood cell are gained and agree well with the previous optical phase models. Analysis shows that the resolution of introduced system reaches sub-micron. This method not only quickly gives quantitative phase distribution of cells, but also measures a large number of cells simultaneously. So it is potential in the use of real-time observing and quantitative analyzing of cells in vivo.

  4. Reconstruction of Sound Source Pressures in an Enclosure Using the Phased Beam Tracing Method

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Ih, Jeong-Guon

    2009-01-01

    Source identification in an enclosure is not an easy task due to complicated wave interference and wall reflections, in particular, at mid-high frequencies. In this study, a phased beam tracing method was applied to the reconstruction of source pressures inside an enclosure at medium frequencies......-directional sphere and a cubic source in a rectangular enclosure were taken as examples in the simulation tests. A reconstruction error was investigated by Monte Carlo simulation in terms of field point locations. When the source information was reconstructed by the present method, it was shown that the sound power...

  5. Theoretical study of ferroelectric nanoparticles using phase reconstructed electron microscopy

    DEFF Research Database (Denmark)

    Phatak, C.; Petford-Long, A. K.; Beleggia, Marco

    2014-01-01

    Ferroelectric nanostructures are important for a variety of applications in electronic and electro-optical devices, including nonvolatile memories and thin-film capacitors. These applications involve stability and switching of polarization using external stimuli, such as electric fields. We present...... a theoretical model describing how the shape of a nanoparticle affects its polarization in the absence of screening charges, and quantify the electron-optical phase shift for detecting ferroelectric signals with phase-sensitive techniques in a transmission electron microscope. We provide an example phase shift...

  6. Identify the Rotating Stall in Centrifugal Compressors by Fractal Dimension in Reconstructed Phase Space

    Directory of Open Access Journals (Sweden)

    Le Wang

    2015-11-01

    Full Text Available Based on phase space reconstruction and fractal dynamics in nonlinear dynamics, a method is proposed to extract and analyze the dynamics of the rotating stall in the impeller of centrifugal compressor, and some numerical examples are given to verify the results as well. First, the rotating stall of an existing low speed centrifugal compressor (LSCC is numerically simulated, and the time series of pressure in the rotating stall is obtained at various locations near the impeller outlet. Then, the phase space reconstruction is applied to these pressure time series, and a low-dimensional dynamical system, which the dynamics properties are included in, is reconstructed. In phase space reconstruction, C–C method is used to obtain the key parameters, such as time delay and the embedding dimension of the reconstructed phase space. Further, the fractal characteristics of the rotating stall are analyzed in detail, and the fractal dimensions are given for some examples to measure the complexity of the flow in the post-rotating stall. The results show that the fractal structures could reveal the intrinsic dynamics of the rotating stall flow and could be considered as a characteristic to identify the rotating stall.

  7. Object wave reconstruction by speckle illumination and phase retrieval

    DEFF Research Database (Denmark)

    Almoro, Percival; Hanson, Steen Grüner

    2009-01-01

    An innovative setup for the speckle-based phase retrieval method is proposed. In the conventional setup, a plane wave illuminates the test object and the transmitted wavefront is incident on a diffuser aperture generating a speckle field. The sampled speckle intensities at axially displaced planes...... are input into a phase retrieval algorithm based on a wave propagation equation. In the new setup, the arrangement of the diffuser and the object is reversed. A plane wave incident on the diffuser generates a speckle field which, in turn, is used to illuminate the object. The transmitted wavefront...

  8. Hybrid phase retrieval approach for reconstruction of in-line digital holograms without twin image

    Science.gov (United States)

    Zhao, Jie; Wang, Dayong; Zhang, Fucai; Wang, Yunxin

    2011-09-01

    A hybrid phase retrieval approach is proposed to address the twin image problem in the reconstruction of in-line digital holograms. The approach is a variant iterative transform algorithm and exploits two mostly natural constraints of a sample, namely, the finite transmission and the finite support. Here, the initial sample support estimate is first refined by applying the finite transmission constraint with phase flipping. The approach provides better reconstruction than if only the finite transmission constraint is used and improve the convergence rate of Fienup's algorithm owing to a better estimate of support especially for strong samples with complex structures. Both simulation and experimental results are presented.

  9. On the non-equivalence of observables in phase-space reconstructions from recorded time series

    Science.gov (United States)

    Letellier, C.; Maquet, J.; LeSceller, L.; Gouesbet, G.; Aguirre, L. A.

    1998-10-01

    In practical problems of phase-space reconstruction, it is usually the case that the reconstruction is much easier using a particular recorded scalar variable. This seems to contradict the general belief that all variables of a dynamical system are equivalent in phase-space reconstruction problems. This paper will argue that, in many cases, the choice of a particular scalar time series from which to reconstruct the original dynamics could be critical. It is argued that different dynamical variables do not provide the same level of information (observability) of the underlying dynamics and, as a consequence, the quality of a global reconstruction critically depends on the recorded variable. Examples in which the choice of observables is critical are discussed and the level of information contained in a given variable is quantified in the case where the original system is known. A clear example of such a situation arises in the Rössler system for which the performance of a global vector field reconstruction technique is investigated using time series of variables x, y or z, taken one at a time.

  10. Evaluation of a new reconstruction algorithm for x-ray phase-contrast imaging

    Science.gov (United States)

    Seifert, Maria; Hauke, Christian; Horn, Florian; Lachner, Sebastian; Ludwig, Veronika; Pelzer, Georg; Rieger, Jens; Schuster, Max; Wandner, Johannes; Wolf, Andreas; Michel, Thilo; Anton, Gisela

    2016-04-01

    X-ray grating-based phase-contrast imaging might open up entirely new opportunities in medical imaging. However, transferring the interferometer technique from laboratory setups to conventional imaging systems the necessary rigidity of the system is difficult to achieve. Therefore, vibrations or distortions of the system lead to inaccuracies within the phase-stepping procedure. Given insufficient stability of the phase-step positions, up to now, artifacts in phase-contrast images occur, which lower the image quality. This is a problem with regard to the intended use of phase-contrast imaging in clinical routine as for example tiny structures of the human anatomy cannot be observed. In this contribution we evaluate an algorithm proposed by Vargas et.al.1 and applied to X-ray imaging by Pelzer et.al. that enables us to reconstruct a differential phase-contrast image without the knowledge of the specific phase-step positions. This method was tested in comparison to the standard reconstruction by Fourier analysis. The quality of phase-contrast images remains stable, even if the phase-step positions are completely unknown and not uniformly distributed. To also achieve attenuation and dark-field images the proposed algorithm has been combined with a further algorithm of Vargas et al.3 Using this algorithm, the phase-step positions can be reconstructed. With the help of the proper phase-step positions it is possible to get information about the phase, the amplitude and the offset of the measured data. We evaluated this algorithm concerning the measurement of thick objects which show a high absorbency.

  11. Super-resolution phase reconstruction technique in electron holography with a stage-scanning system

    Science.gov (United States)

    Lei, Dan; Mitsuishi, Kazutaka; Harada, Ken; Shimojo, Masayuki; Ju, Dongying; Takeguchi, Masaki

    2014-02-01

    Super-resolution image reconstruction is a digital signal processing technique that allows creating a high-resolution image from multiple low-resolution images taken at slightly different positions. We introduce the super-resolution image reconstruction technique into electron holography for reconstructing phase images as follows: the studied specimen is shifted step-wise with a high-precision piezo holder, and a series of holograms is recorded. When the step size is not a multiple of the CCD pixel size, processing of the acquired series results in a higher pixel density and spatial resolution as compared to the phase image obtained with conventional holography. The final resolution exceeds the limit of the CCD pixel size divided by the magnification.

  12. In-line phase contrast micro-CT reconstruction for biomedical specimens.

    Science.gov (United States)

    Fu, Jian; Tan, Renbo

    2014-01-01

    X-ray phase contrast micro computed tomography (micro-CT) can non-destructively provide the internal structure information of soft tissues and low atomic number materials. It has become an invaluable analysis tool for biomedical specimens. Here an in-line phase contrast micro-CT reconstruction technique is reported, which consists of a projection extraction method and the conventional filter back-projection (FBP) reconstruction algorithm. The projection extraction is implemented by applying the Fourier transform to the forward projections of in-line phase contrast micro-CT. This work comprises a numerical study of the method and its experimental verification using a biomedical specimen dataset measured at an X-ray tube source micro-CT setup. The numerical and experimental results demonstrate that the presented technique can improve the imaging contrast of biomedical specimens. It will be of interest for a wide range of in-line phase contrast micro-CT applications in medicine and biology.

  13. Exposure to Low Dose of Cinnabar (a Naturally Occurring Mercuric Sulfide (HgS Caused Neurotoxicological Effects in Offspring Mice

    Directory of Open Access Journals (Sweden)

    Chun-Fa Huang

    2012-01-01

    Full Text Available Cinnabar, a naturally occurring mercuric sulfide (HgS, has long been used in Chinese mineral medicine for more than 2000 years. Although mercury is well-known for its toxicity, whether cinnabar induces neurotoxicity, especially in infants and children, is unknown. The purpose of this study was to explore the neurotoxic effects of low-dose of cinnabar (10 mg/kg/day on developing mice. The results revealed neurobehavioral defects in F1-C-Cin group, which were associated with Hg accumulation, increased NOx levels in whole blood, and Na+/K+-ATPase activities in brain tissues. F1- and F2-Cin-V groups were found to increase brain Hg contents and prominent neurobehavioral defects compared with F1-C-V group, suggesting that the fetal brain was more susceptible to irreversible effects for cinnabar-induced damage. Moreover, F1- and F2-Cin-Cin groups had severely neurobehavioral dysfunctions, closely correlated with the further alteration of NOx levels and Na+/K+-ATPase activities than F1- and F2-C-Cin groups. Effects in F2-Cin-Cin group were more significant than those in F1-Cin-Cin group. In conclusion, this study demonstrates that exposure to low-dose of cinnabar during the perinatal and developmental stages results in irreversible and severe injuries of the neurotoxicity in offspring, and NOx and Na+/K+-ATPase activities may exist potential and useful biomarkers for neurotoxicity-induced by low-doses of mercuric compounds.

  14. Reconstruction of purely absorbing, absorbing and phase-shifting, and strong phase-shifting objects from their single-shot in-line holograms

    CERN Document Server

    Latychevskaia, Tatiana

    2015-01-01

    We address the problem of reconstructing phase-shifting objects from their single shot in-line holograms. We show that a phase-shifting object cannot be reliably recovered from its in-line hologram by conventional reconstruction routines but that an iterative reconstruction should be applied. We demonstrate examples of simulated in-line holograms of objects with the following properties: purely absorbing, both absorbing and phase shifting, and strong phase-shifting. We investigate the effects of noise and interference resolution in holograms on the reconstruction results and discuss details of an optimal iterative procedure to quantitatively recover the correct absorbing and phase-shifting properties of the object. We also review previously published reconstructions of experimental holograms and summarize the optimal parameters for retrieval of phase-shifting objects from their in-line holograms.

  15. FY 1991 project plan for the Hanford Environmental Dose Reconstruction Project, Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    1991-02-01

    Phase 1 of the Hanford Environmental Dose Reconstruction Project was designed to develop and demonstrate a method for estimating radiation doses people may have received from Hanford Site operations since 1944. The method researchers developed relied on a variety of measured and reconstructed data as input to a modular computer model that generates dose estimates and their uncertainties. As part of Phase 1, researchers used the reconstructed data and computer model to calculate preliminary dose estimates for populations in a limited geographical area and time period. Phase 2, now under way, is designed to evaluate the Phase 1 data and model and improve them to calculate more accurate and precise dose estimates. Phase 2 will also be used to obtain preliminary estimates of two categories of doses: for Native American tribes and for individuals included in the pilot phase of the Hanford Thyroid Disease Study (HTDS). TSP Directive 90-1 required HEDR staff to develop Phase 2 task plans for TSP approval. Draft task plans for Phase 2 were submitted to the TSP at the October 11--12, 1990 public meeting, and, after discussions of each activity and associated budget needs, the TSP directed HEDR staff to proceed with a slate of specific project activities for FY 1991 of Phase 2. This project plan contains detailed information about those activities. Phase 2 is expected to last 15--18 months. In mid-FY 1991, project activities and budget will be reevaluated to determine whether technical needs or priorities have changed. Separate from, but related to, this project plan, will be an integrated plan for the remainder of the project. HEDR staff will work with the TSP to map out a strategy that clearly describes end products'' for the project and the work necessary to complete them. This level of planning will provide a framework within which project decisions in Phases 2, 3, and 4 can be made.

  16. Reconstruction

    Directory of Open Access Journals (Sweden)

    Stefano Zurrida

    2011-01-01

    Full Text Available Breast cancer is the most common cancer in women. Primary treatment is surgery, with mastectomy as the main treatment for most of the twentieth century. However, over that time, the extent of the procedure varied, and less extensive mastectomies are employed today compared to those used in the past, as excessively mutilating procedures did not improve survival. Today, many women receive breast-conserving surgery, usually with radiotherapy to the residual breast, instead of mastectomy, as it has been shown to be as effective as mastectomy in early disease. The relatively new skin-sparing mastectomy, often with immediate breast reconstruction, improves aesthetic outcomes and is oncologically safe. Nipple-sparing mastectomy is newer and used increasingly, with better acceptance by patients, and again appears to be oncologically safe. Breast reconstruction is an important adjunct to mastectomy, as it has a positive psychological impact on the patient, contributing to improved quality of life.

  17. Phase reconstruction of living human embryonic kidney 293 cells based on two off-axis holograms

    Science.gov (United States)

    Zhou, Wenjing; Yu, Yingjie; Duan, Yanhong; Asundi, Anand

    2008-11-01

    In this paper, we validate experimentally the potential of off-axis digital micro-holography for 3D image reconstruction of a live Human Embryonic Kidney 293(HEK293) cell that is widely used as transfection and expression. A subtraction method of two off-axis holograms to reconstruct the phase of the live microscopic object is discussed. The presented subtraction method can remove some main noise, for example, the quadratic phase aberration introduced by microscope objective (MO), other phase aberration introduced by the liquid in tank and other interference noise introduced by the optical parts. Thus an improvement in the measurement precision of live cells in aqueous solution is observed. The potential of this method is demonstrated by providing the phase reconstruction results of a phase grating and a single HEK293 cell. The results showed good correspondence to the actual character of HEK293 cell prove the capability of digital micro-holography as a tool to monitor the dynamic transfection process of the living HEK 293 cells.

  18. Electron bunch profile reconstruction based on phase-constrained iterative algorithm

    Science.gov (United States)

    Bakkali Taheri, F.; Konoplev, I. V.; Doucas, G.; Baddoo, P.; Bartolini, R.; Cowley, J.; Hooker, S. M.

    2016-03-01

    The phase retrieval problem occurs in a number of areas in physics and is the subject of continuing investigation. The one-dimensional case, e.g., the reconstruction of the temporal profile of a charged particle bunch, is particularly challenging and important for particle accelerators. Accurate knowledge of the longitudinal (time) profile of the bunch is important in the context of linear colliders, wakefield accelerators and for the next generation of light sources, including x-ray SASE FELs. Frequently applied methods, e.g., minimal phase retrieval or other iterative algorithms, are reliable if the Blaschke phase contribution is negligible. This, however, is neither known a priori nor can it be assumed to apply to an arbitrary bunch profile. We present a novel approach which gives reproducible, most-probable and stable reconstructions for bunch profiles (both artificial and experimental) that would otherwise remain unresolved by the existing techniques.

  19. Event reconstruction methods for the HypHI Phase 0 experiment at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Rappold, C., E-mail: c.rappold@gsi.d [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); IPHC/DRS Universite de Strasbourg, 4 rue Blaise Pascal, 67070 Strasbourg Cedex (France); Saito, T.R., E-mail: T.Saito@gsi.d [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Institut fuer Kernphysik, Johannes Gutenberg Universitaet Mainz, J.J.Becherweg 45, 55099 Mainz (Germany); Bianchin, S. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Borodina, O. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Institut fuer Kernphysik, Johannes Gutenberg Universitaet Mainz, J.J.Becherweg 45, 55099 Mainz (Germany); Kavatsyuk, M. [KVI, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Maas, F. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Institut fuer Kernphysik, Johannes Gutenberg Universitaet Mainz, J.J.Becherweg 45, 55099 Mainz (Germany); Minami, S. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Nakajima, D. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ozel-Tashenov, B. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Department of Physics, Nigde University, 51100 Nigde (Turkey); Trautmann, W. [GSI Helmholtz Center for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany)

    2010-10-01

    The first experiment of the HypHI project, Phase 0, at GSI-Darmstadt performs the feasibility study of precise hypernuclear spectroscopy with heavy ion induced reactions by using the collision of {sup 6}Li at 2 A GeV on a {sup 12}C target. In preparation of the Phase 0 experiment, simulation studies have been performed with a dedicated event reconstruction procedure. Details of this procedure will be discussed in this paper as well as the physics motivation of the Phase 0 and the experimental setup used during simulations. Expected results of the experiment will also be discussed.

  20. 256-Slice coronary computed tomographic angiography in patients with atrial fibrillation: optimal reconstruction phase and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Seitaro; Yuki, Hideaki; Kidoh, Masafumi; Utsunomiya, Daisuke; Nakaura, Takeshi; Namimoto, Tomohiro; Yamashita, Yasuyuki [Kumamoto University, Department of Diagnostic Radiology, Faculty of Life Sciences, Chuou-ku, Kumamoto (Japan); Honda, Keiichi; Yoshimura, Akira; Katahira, Kazuhiro [Kumamoto Chuo Hospital, Department of Diagnostic Radiology, Minami-ku, Kumamoto (Japan); Noda, Katsuo; Oshima, Shuichi [Kumamoto Chuo Hospital, Department of Cardiology, Minami-ku, Kumamoto (Japan)

    2016-01-15

    To assess the optimal reconstruction phase and the image quality of coronary computed tomographic angiography (CCTA) in patients with atrial fibrillation (AF). We performed CCTA in 60 patients with AF and 60 controls with sinus rhythm. The images were reconstructed in multiple phases in all parts of the cardiac cycle, and the optimal reconstruction phase with the fewest motion artefacts was identified. The coronary artery segments were visually evaluated to investigate their assessability. In 46 (76.7 %) patients, the optimal reconstruction phase was end-diastole, whereas in 6 (10.0 %) patients it was end-systole or mid-diastole, and in 2 (3.3 %) patients it was another cardiac phase. In 53 (88.3 %) of the controls, the optimal reconstruction phase was mid-diastole, whereas it was end-systole in 4 (6.7 %), and in 3 (5.0 %) it was another cardiac phase. There was a significant difference between patients with AF and the controls in the optimal phase (p < 0.01) but not in the visual image quality score (p = 0.06). The optimal reconstruction phase in most patients with AF was the end-diastolic phase. The end-systolic phase tended to be optimal in AF patients with higher average heart rates. (orig.)

  1. Low-dose multiphase abdominal CT reconstruction with phase-induced swap prior

    Science.gov (United States)

    Selim, Mona; Rashed, Essam A.; Kudo, Hiroyuki

    2016-10-01

    Multiphase abdominal CT is an imaging protocol in which the patient is scanned at different phases before and after the injection of a contrast agent. Reconstructed images with different concentrations of contrast material provide useful information for effective detection of abnormalities. However, several scanning during a short period of time eventually increase the patient radiation dose to a remarkable value up to a risky level. Reducing the patient dose by modulating the x-ray tube current or acquiring the projection data through a small number of views are known to degrade the image quality and reduce the possibility to be useful for diagnosis purpose. In this work, we propose a novel multiphase abdominal CT imaging protocol with patient dose reduction and high image quality. The image reconstruction cost function consists of two terms, namely the data fidelity term and penalty term to enforce the anatomical similarity in successive contrast phase reconstruction. The prior information, named phase-induced swap prior (PISP) is computed using total variation minimization of image acquired from different contrast phases. The new method is evaluated through a simulation study using digital abdominal phantom and real data and results are promising.

  2. Neural network forecasting model based on phase space re-construction in water yield of mine

    Institute of Scientific and Technical Information of China (English)

    LIU Wei-lin; DONG Zeng-chuan; CHEN Nan-xiang; CAO Lian-hai

    2007-01-01

    The neutral network forecasting model based on the phase space reconstruction was proposed. First, through reconstructing the phase space, the time series of single variable was done excursion and expanded into multi- dimension series which included the ergodic information and more rich information could be excavated. Then, on the basis of the embedding dimension of the time series, the structure form of neutral network was constructed, of which the node number in input layer was the embedding dimension of the time series minus 1, and the node number in output layers was 1. Finally, as an example,the model was applied for water yield of mine forecasting. The result shows that the model has good fitting accuracy and forecasting precision.

  3. TV-regularized phase reconstruction in differential-interference-contrast (DIC) microscopy

    Science.gov (United States)

    Rebegoldi, Simone; Bautista, Lola; Blanc-Féraud, Laure; Prato, Marco; Zanni, Luca; Plata, Arturo

    2016-10-01

    In this paper we address the problem of reconstructing the phase from color images acquired with differential-interference-contrast (DIC) microscopy. In particular, we reformulate the problem as the minimization of a least-squares fidelity function regularized with a total variation term, and we address the solution by exploiting a recently proposed inexact forward-backward approach. The effectiveness of this method is assessed on a realistic synthetic test.

  4. Application analysis of empirical mode decomposition and phase space reconstruction in dam time-varying characteristic

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In view of some courses of the time-varying characteristics processing in the analysis of dam deformation,the paper proposes a new method to analyze the dam time-varying characteristic based on the empirical mode decomposition and phase space reconstruction theory.First of all,to reduce the influences on the traditional statistical model from human factors and assure the analysis accuracy,response variables of the time-varying characteristic are obtained by the way of the empirical mode decomposition;and then,a phase plane of those variables is reconstructed to investigate their processing rules.These methods have already been applied to an actual project and the results showed that data interpretation with the assists of empirical mode decomposition and phase space reconstruction is effective in analyzing the perturbations of response variables,explicit in reflecting the entire development process,and valid for obtaining the evolution rules of the time-varying characteristic.This methodology is a powerful technical support for people to further master the rules of dam operation.

  5. Identification of superficial defects in reconstructed 3D objects using phase-shifting fringe projection

    Science.gov (United States)

    Madrigal, Carlos A.; Restrepo, Alejandro; Branch, John W.

    2016-09-01

    3D reconstruction of small objects is used in applications of surface analysis, forensic analysis and tissue reconstruction in medicine. In this paper, we propose a strategy for the 3D reconstruction of small objects and the identification of some superficial defects. We applied a technique of projection of structured light patterns, specifically sinusoidal fringes and an algorithm of phase unwrapping. A CMOS camera was used to capture images and a DLP digital light projector for synchronous projection of the sinusoidal pattern onto the objects. We implemented a technique based on a 2D flat pattern as calibration process, so the intrinsic and extrinsic parameters of the camera and the DLP were defined. Experimental tests were performed in samples of artificial teeth, coal particles, welding defects and surfaces tested with Vickers indentation. Areas less than 5cm were studied. The objects were reconstructed in 3D with densities of about one million points per sample. In addition, the steps of 3D description, identification of primitive, training and classification were implemented to recognize defects, such as: holes, cracks, roughness textures and bumps. We found that pattern recognition strategies are useful, when quality supervision of surfaces has enough quantities of points to evaluate the defective region, because the identification of defects in small objects is a demanding activity of the visual inspection.

  6. A New PWM Modifying Technique for Reconstructing Three-phase Currents from DC Bus Current

    Science.gov (United States)

    Aoyagi, Shigehisa; Iwaji, Yoshitaka; Tobari, Kazuaki; Sakamoto, Kiyoshi

    Vector control is used to drive a DC brushless motor and generally needs current information. DC bus current detection is often adopted as a low cost method for reconstructing three-phase currents. PWM modifying techniques increase the DC pulse duration, thereby enabling easy detection of the DC bus current. However, these techniques have two problems: reducing a noise frequency and making the reconstructed current waveforms distorted by current ripple. In the techniques, modification signals are added to the three-phase voltage commands; the sum of the signals over a single cycle is zero. The authors examined several PWM modifying techniques from the points of view of noise and current distortion performance. One of the techniques had a good noise performance, and the frequency component of the noise was the same as the carrier frequency (fc). However, the reconstructed current waveforms were distorted. The total harmonic distortion (THD) varied from 1.7% to 4.1%. Another technique had a very poor noise performance, and the frequency component on the noise was one-fourth of fc. The authors developed a new PWM modifying method called “Half Pulse Shift”, which achieves the optimum noise and current distortion performance. The frequency component of the new method was two-thirds of fc, and the current waveforms were not distorted; the THD in the simulations and experiments was 0.5%-1.4% and 3.4%-3.6%, respectively.

  7. Draft Air Pathway Report: Phase 1 of the Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-20

    This report summarizes the air pathway portion of the first phase of the Hanford Environmental Dose Reconstruction (HEDR) Project, conducted by Battelle staff at the Pacific Northwest Laboratory under the direction of an independent Technical Steering Panel. The HEDR Project is estimating historical radiation doses that could have been received by populations near the Department of Energy's Hanford Site, in southeastern Washington State. Phase 1 of the air-pathway dose reconstruction sought to determine whether dose estimates could be calculated for populations in the 10 counties nearest the Hanford Site from atmospheric releases of iodine-131 from the site from 1944--1947. Phase 1 demonstrated the following: HEDR-calculated source-term estimates of iodine-131 releases to the atmosphere were within 20% of previously published estimates; calculated vegetation concentrations of iodine-131 agree well with previously published measurements; the highest of the Phase 1 preliminary dose estimates to the thyroid are consistent with independent, previously published estimates of doses to maximally exposed individuals; and relatively crude, previously published measurements of thyroid burdens for Hanford workers are in the range of average burdens that the HEDR model estimated for similar reference individuals'' for the period 1944--1947. 4 refs., 10 figs., 9 tabs.

  8. A high precision phase reconstruction algorithm for multi-laser guide stars adaptive optics

    Science.gov (United States)

    He, Bin; Hu, Li-Fa; Li, Da-Yu; Xu, Huan-Yu; Zhang, Xing-Yun; Wang, Shao-Xin; Wang, Yu-Kun; Yang, Cheng-Liang; Cao, Zhao-Liang; Mu, Quan-Quan; Lu, Xing-Hai; Xuan, Li

    2016-09-01

    Adaptive optics (AO) systems are widespread and considered as an essential part of any large aperture telescope for obtaining a high resolution imaging at present. To enlarge the imaging field of view (FOV), multi-laser guide stars (LGSs) are currently being investigated and used for the large aperture optical telescopes. LGS measurement is necessary and pivotal to obtain the cumulative phase distortion along a target in the multi-LGSs AO system. We propose a high precision phase reconstruction algorithm to estimate the phase for a target with an uncertain turbulence profile based on the interpolation. By comparing with the conventional average method, the proposed method reduces the root mean square (RMS) error from 130 nm to 85 nm with a 30% reduction for narrow FOV. We confirm that such phase reconstruction algorithm is validated for both narrow field AO and wide field AO. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174274, 11174279, 61205021, 11204299, 61475152, and 61405194) and State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences.

  9. Reconstructing source-sink dynamics in a population with a pelagic dispersal phase.

    Directory of Open Access Journals (Sweden)

    Kun Chen

    Full Text Available For many organisms, the reconstruction of source-sink dynamics is hampered by limited knowledge of the spatial assemblage of either the source or sink components or lack of information on the strength of the linkage for any source-sink pair. In the case of marine species with a pelagic dispersal phase, these problems may be mitigated through the use of particle drift simulations based on an ocean circulation model. However, when simulated particle trajectories do not intersect sampling sites, the corroboration of model drift simulations with field data is hampered. Here, we apply a new statistical approach for reconstructing source-sink dynamics that overcomes the aforementioned problems. Our research is motivated by the need for understanding observed changes in jellyfish distributions in the eastern Bering Sea since 1990. By contrasting the source-sink dynamics reconstructed with data from the pre-1990 period with that from the post-1990 period, it appears that changes in jellyfish distribution resulted from the combined effects of higher jellyfish productivity and longer dispersal of jellyfish resulting from a shift in the ocean circulation starting in 1991. A sensitivity analysis suggests that the source-sink reconstruction is robust to typical systematic and random errors in the ocean circulation model driving the particle drift simulations. The jellyfish analysis illustrates that new insights can be gained by studying structural changes in source-sink dynamics. The proposed approach is applicable for the spatial source-sink reconstruction of other species and even abiotic processes, such as sediment transport.

  10. In situ imaging and height reconstruction of phase separation processes in polymer blends during spin coating.

    Science.gov (United States)

    Ebbens, Stephen; Hodgkinson, Richard; Parnell, Andrew J; Dunbar, Alan; Martin, Simon J; Topham, Paul D; Clarke, Nigel; Howse, Jonathan R

    2011-06-28

    Spin coating polymer blend thin films provides a method to produce multiphase functional layers of high uniformity covering large surface areas. Applications for such layers include photovoltaics and light-emitting diodes where performance relies upon the nanoscale phase separation morphology of the spun film. Furthermore, at micrometer scales, phase separation provides a route to produce self-organized structures for templating applications. Understanding the factors that determine the final phase-separated morphology in these systems is consequently an important goal. However, it has to date proved problematic to fully test theoretical models for phase separation during spin coating, due to the high spin speeds, which has limited the spatial resolution of experimental data obtained during the coating process. Without this fundamental understanding, production of optimized micro- and nanoscale structures is hampered. Here, we have employed synchronized stroboscopic illumination together with the high light gathering sensitivity of an electron-multiplying charge-coupled device camera to optically observe structure evolution in such blends during spin coating. Furthermore the use of monochromatic illumination has allowed interference reconstruction of three-dimensional topographies of the spin-coated film as it dries and phase separates with nanometer precision. We have used this new method to directly observe the phase separation process during spinning for a polymer blend (PS-PI) for the first time, providing new insights into the spin-coating process and opening up a route to understand and control phase separation structures.

  11. Metal-insulator transition and nanoscale phase separation in a hole-doped surface reconstruction

    Science.gov (United States)

    Mulugeta, Daniel; Snijders, Paul; Weitering, Hanno

    2014-03-01

    Doping, the deliberate introduction of impurities to alter electronic or magnetic properties, has been a tremendously successful method to study and understand systems with multiple competing interactions, as reflected in both the widespread use of doped semiconductors and in the large number of emergent electronic phases in doping-dependent phase diagrams of e.g. complex oxides. In low dimensional systems, however, the perturbation to the crystal lattice by the dopant atoms can overwhelm a delicate balance of interactions in e.g. a ground state with coexisting phases. Here we introduce a modulation doping technique used to dope holes in a surface reconstruction of Sn on Si(111). Using variable and low temperature scanning tunneling microscopy and spectroscopy, we observe a doping-induced metal-insulator phase transition that is of a displacive nature, contrasting with the order-disorder nature of other surface phase transitions. Moreover, the transition leads to an intrinsic nanoscale phase coexistence at 5 K never before observed on semiconductor surfaces. Clearly, modulation doping allows us to study the delicate balance of interactions in the phase diagram of low-dimensional electronic surface systems that is otherwise experimentally inaccessible. Funded by NSF DMR.

  12. Robust Compressive Phase Retrieval via L1 Minimization With Application to Image Reconstruction

    CERN Document Server

    Yang, Zai; Xie, Lihua

    2013-01-01

    Phase retrieval refers to a classical nonconvex problem of recovering a signal from its Fourier magnitude measurements. Inspired by the compressed sensing technique, signal sparsity is exploited in recent studies of phase retrieval to reduce the required number of measurements, known as compressive phase retrieval (CPR). In this paper, l1 minimization problems are formulated for CPR to exploit the signal sparsity and alternating direction algorithms are presented for problem solving. For real-valued, nonnegative image reconstruction, the image of interest is shown to be an optimal solution of the formulated l1 minimization in the noise free case. Numerical simulations demonstrate that the proposed approach is fast, accurate and robust to measurements noises.

  13. Columbia River pathway report: phase I of the Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    1991-07-01

    This report summarizes the river-pathway portion of the first phase of the Hanford Environmental Dose Reconstruction (HEDR) Project. The HEDR Project is estimating radiation doses that could have been received by the public from the Department of Energy's Hanford Site, in southeastern Washington State. Phase 1 of the river-pathway dose reconstruction effort sought to determine whether dose estimates could be calculated for populations in the area from above the Hanford Site at Priest Rapids Dam to below the site at McNary Dam from January 1964 to December 1966. Of the potential sources of radionuclides from the river, fish consumption was the most important. Doses from drinking water were lower at Pasco than at Richland and lower at Kennewick than at Pasco. The median values of preliminary dose estimates calculated by HEDR are similar to independent, previously published estimates of average doses to Richland residents. Later phases of the HEDR Project will address dose estimates for periods other than 1964--1966 and for populations downstream of McNary Dam. 17 refs., 19 figs., 1 tab.

  14. Mid- and long-term runoff predictions by an improved phase-space reconstruction model.

    Science.gov (United States)

    Hong, Mei; Wang, Dong; Wang, Yuankun; Zeng, Xiankui; Ge, Shanshan; Yan, Hengqian; Singh, Vijay P

    2016-07-01

    In recent years, the phase-space reconstruction method has usually been used for mid- and long-term runoff predictions. However, the traditional phase-space reconstruction method is still needs to be improved. Using the genetic algorithm to improve the phase-space reconstruction method, a new nonlinear model of monthly runoff is constructed. The new model does not rely heavily on embedding dimensions. Recognizing that the rainfall-runoff process is complex, affected by a number of factors, more variables (e.g. temperature and rainfall) are incorporated in the model. In order to detect the possible presence of chaos in the runoff dynamics, chaotic characteristics of the model are also analyzed, which shows the model can represent the nonlinear and chaotic characteristics of the runoff. The model is tested for its forecasting performance in four types of experiments using data from six hydrological stations on the Yellow River and the Yangtze River. Results show that the medium-and long-term runoff is satisfactorily forecasted at the hydrological stations. Not only is the forecasting trend accurate, but also the mean absolute percentage error is no more than 15%. Moreover, the forecast results of wet years and dry years are both good, which means that the improved model can overcome the traditional ''wet years and dry years predictability barrier,'' to some extent. The model forecasts for different regions are all good, showing the universality of the approach. Compared with selected conceptual and empirical methods, the model exhibits greater reliability and stability in the long-term runoff prediction. Our study provides a new thinking for research on the association between the monthly runoff and other hydrological factors, and also provides a new method for the prediction of the monthly runoff.

  15. A novel approach for the diagnosis of ventricular tachycardia based on phase space reconstruction of ECG

    CERN Document Server

    Koulaouzidis, George; Cappiello, Grazia; Mazomenos, Evangelos B; Maharatna, Koushik; Morgan, John

    2014-01-01

    Ventricular arrhythmias comprise a group of disorders which manifest clinically in a variety of ways from ventricular premature beats (VPB) and no sustained ventricular tachycardia (in healthy subjects) to sudden cardiac death due to ventricular tachyarrhythmia in patients with and/or without structural heart disease. Ventricular fibrillation (VF) and ventricular tachycardia (VT) are the most common electrical mechanisms for cardiac arrest. Accurate and automatic recognition of these arrhythmias from electrocardiography (ECG) is a crucial task for medical professionals. The purpose of this research is to develop a new index for the differential diagnosis of normal sinus rhythm (SR) and ventricular arrhythmias, based on phase space reconstruction (PSR).

  16. Phase-sensitive optical pulse characterization on a chip via Spectral Phase Interferometry for Direct Electric-Field Reconstruction (SPIDER)

    CERN Document Server

    Pasquazi, Alessia; Park, Yongwoo; Little, Brent E; Chu, Sai T; Morandotti, Roberto; Azana, Jose; Moss, David J

    2014-01-01

    The recent introduction of coherent optical communications has created a compelling need for ultra-fast phase-sensitive measurement techniques operating at milliwatt peak power levels and in time scales ranging from sub-picoseconds to nanoseconds. Previous reports of ultrafast optical signal measurements in integrated platforms[8-10] include time-lens temporal imaging on a silicon chip[8,9] and waveguide-based Frequency-Resolved Optical Gating (FROG). Time-lens imaging is phase insensitive while waveguide-based FROG methods require the integration of long tuneable delay lines - still an unsolved challenge. Here, we report a device capable of characterizing both the amplitude and phase of ultrafast optical pulses with the aid of a synchronized incoherently-related clock pulse. It is based on a novel variation of Spectral Phase Interferometry for Direct Electric-Field Reconstruction (SPIDER)that exploits degenerate four-wave-mixing (FWM) in a CMOS compatible chip. We measure pulses with 1THz, and up to 100ps pu...

  17. Single-shot laser pulse reconstruction based on self-phase modulated spectra measurements

    Science.gov (United States)

    Anashkina, Elena A.; Ginzburg, Vladislav N.; Kochetkov, Anton A.; Yakovlev, Ivan V.; Kim, Arkady V.; Khazanov, Efim A.

    2016-09-01

    We report a method for ultrashort pulse reconstruction based only on the pulse spectrum and two self-phase modulated (SPM) spectra measured after pulse propagation through thin media with a Kerr nonlinearity. The advantage of this method is that it is a simple and very effective tool for characterization of complex signals. We have developed a new retrieval algorithm that was verified by reconstructing numerically generated fields, such as a complex electric field of double pulses and few-cycle pulses with noises, pedestals and dips down to zero spectral intensity, which is challenging for commonly used techniques. We have also demonstrated a single-shot implementation of the technique for the reconstruction of experimentally obtained pulses. This method can be used for high power laser systems operating in a single-shot mode in the optical, near- and mid-IR spectral ranges. The method is robust, low cost, stable to noise, does not require a priori information, and has no ambiguity related to time direction.

  18. 3D shape reconstruction of specular surfaces by using phase measuring deflectometry

    Science.gov (United States)

    Zhou, Tian; Chen, Kun; Wei, Haoyun; Li, Yan

    2016-10-01

    The existing estimation methods for recovering height information from surface gradient are mainly divided into Modal and Zonal techniques. Since specular surfaces used in the industry always have complex and large areas, considerations must be given to both the improvement of measurement accuracy and the acceleration of on-line processing speed, which beyond the capacity of existing estimations. Incorporating the Modal and Zonal approaches into a unifying scheme, we introduce an improved 3D shape reconstruction version of specular surfaces based on Phase Measuring Deflectometry in this paper. The Modal estimation is firstly implemented to derive the coarse height information of the measured surface as initial iteration values. Then the real shape can be recovered utilizing a modified Zonal wave-front reconstruction algorithm. By combining the advantages of Modal and Zonal estimations, the proposed method simultaneously achieves consistently high accuracy and dramatically rapid convergence. Moreover, the iterative process based on an advanced successive overrelaxation technique shows a consistent rejection of measurement errors, guaranteeing the stability and robustness in practical applications. Both simulation and experimentally measurement demonstrate the validity and efficiency of the proposed improved method. According to the experimental result, the computation time decreases approximately 74.92% in contrast to the Zonal estimation and the surface error is about 6.68 μm with reconstruction points of 391×529 pixels of an experimentally measured sphere mirror. In general, this method can be conducted with fast convergence speed and high accuracy, providing an efficient, stable and real-time approach for the shape reconstruction of specular surfaces in practical situations.

  19. Sampling and Reconstruction of the Pupil and Electric Field for Phase Retrieval

    Science.gov (United States)

    Dean, Bruce; Smith, Jeffrey; Aronstein, David

    2012-01-01

    This technology is based on sampling considerations for a band-limited function, which has application to optical estimation generally, and to phase retrieval specifically. The analysis begins with the observation that the Fourier transform of an optical aperture function (pupil) can be implemented with minimal aliasing for Q values down to Q = 1. The sampling ratio, Q, is defined as the ratio of the sampling frequency to the band-limited cut-off frequency. The analytical results are given using a 1-d aperture function, and with the electric field defined by the band-limited sinc(x) function. Perfect reconstruction of the Fourier transform (electric field) is derived using the Whittaker-Shannon sampling theorem for 1sampling ratio such that 1phase retrieval estimation. A method was developed for propagating the electro magnetic field with no aliasing, which has been extended to 2-d optical apertures.

  20. Three-Class EEG-Based Motor Imagery Classification Using Phase-Space Reconstruction Technique

    Science.gov (United States)

    Djemal, Ridha; Bazyed, Ayad G.; Belwafi, Kais; Gannouni, Sofien; Kaaniche, Walid

    2016-01-01

    Over the last few decades, brain signals have been significantly exploited for brain-computer interface (BCI) applications. In this paper, we study the extraction of features using event-related desynchronization/synchronization techniques to improve the classification accuracy for three-class motor imagery (MI) BCI. The classification approach is based on combining the features of the phase and amplitude of the brain signals using fast Fourier transform (FFT) and autoregressive (AR) modeling of the reconstructed phase space as well as the modification of the BCI parameters (trial length, trial frequency band, classification method). We report interesting results compared with those present in the literature by utilizing sequential forward floating selection (SFFS) and a multi-class linear discriminant analysis (LDA), our findings showed superior classification results, a classification accuracy of 86.06% and 93% for two BCI competition datasets, with respect to results from previous studies. PMID:27563927

  1. Towards quantitative, atomic-resolution reconstruction of the electrostatic potential via differential phase contrast using electrons

    Energy Technology Data Exchange (ETDEWEB)

    Close, R.; Chen, Z. [School of Physics and Astronomy, Monash University, Clayton, Victoria 3800 (Australia); Shibata, N. [Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656 (Japan); Findlay, S.D., E-mail: scott.findlay@monash.edu [School of Physics and Astronomy, Monash University, Clayton, Victoria 3800 (Australia)

    2015-12-15

    Differential phase contrast images in scanning transmission electron microscopy can be directly and quantitatively related to the gradient of the projected specimen potential provided that (a) the specimen can be treated as a phase object and (b) full 2D diffraction patterns as a function of probe position can be obtained. Both are challenging to achieve in atomic resolution imaging. The former is fundamentally limited by probe spreading and dynamical electron scattering, and we explore its validity domain in the context of atomic resolution differential phase contrast imaging. The latter, for which proof-of-principle experimental data sets exist, is not yet routine. We explore the extent to which more established segmented detector geometries can instead be used to reconstruct a quantitatively good approximation to the projected specimen potential. - Highlights: • Atomic-resolution differential phase contrast (DPC) imaging explored via simulation. • Phase-object approximation limits quantification to specimens a few nanometers thick. • Segmented detectors give good estimates of the diffraction pattern's first moment.

  2. Selection of Embedding Dimension and Delay Time in Phase Space Reconstruction

    Institute of Scientific and Technical Information of China (English)

    MA Hong-guang; HAN Chong-zhao

    2006-01-01

    A new algorithm is proposed for computing the embedding dimension and delay time in phase space reconstruction.It makes use of the zero of the nonbias multiple autocorrelation function of the chaotic time series to determine the time delay,which efficiently depresses the computing error caused by tracing arbitrarily the slop variation of average displacement (AD) in AD algorithm.Thereafter,by means of the iterative algorithm of multiple autocorrelation and Γ test,the near-optimum parameters of embedding dimension and delay time are estimated.This algorithm is provided with a sound theoretic basis,and its computing complexity is relatively lower and not strongly dependent on the data length.The simulated experimental results indicate that the relative error of the correlation dimension of standard chaotic time series is decreased from 4.4% when using conventional algorithm to 1.06% when using this algorithm.The accuracy of invariants in phase space reconstruction is greatly improved.

  3. Spectral-phase interferometry for direct electric-field reconstruction applied to seeded extreme-ultraviolet free-electron lasers

    CERN Document Server

    Mahieu, Benoît; De Ninno, Giovanni; Dacasa, Hugo; Lozano, Magali; Rousseau, Jean-Philippe; Zeitoun, Philippe; Garzella, David; Merdji, Hamed

    2015-01-01

    We present a setup for complete characterization of femtosecond pulses generated by seeded free-electron lasers (FEL's) in the extreme-ultraviolet spectral region. Two delayed and spectrally shifted replicas are produced and used for spectral phase interferometry for direct electric field reconstruction (SPIDER). We show that it can be achieved by a simple arrangement of the seed laser. Temporal shape and phase obtained in FEL simulations are well retrieved by the SPIDER reconstruction, allowing to foresee the implementation of this diagnostic on existing and future sources. This will be a significant step towards an experimental investigation and control of FEL spectral phase.

  4. Experimental evaluation of the ‘transport-of-intensity’ equation for magnetic phase reconstruction in Lorentz transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, Amit, E-mail: akohn@post.tau.ac.il [Department of Materials Science and Engineering, Faculty of Engineering, Tel Aviv University, 69978 Tel Aviv (Israel); Habibi, Avihay; Mayo, Martin [Department of Materials Engineering, Ben-Gurion University of the Negev, 84105 Beer Sheva (Israel)

    2016-01-15

    The ‘transport-of-intensity’ equation (TIE) is a general phase reconstruction methodology that can be applied to Lorentz transmission electron microscopy (TEM) through the use of Fresnel-contrast (defocused) images. We present an experimental study to test the application of the TIE for quantitative magnetic mapping in Lorentz TEM without aberration correction by examining sub-micrometer sized Ni{sub 80}Fe{sub 20} (Permalloy) elements. For a JEOL JEM 2100F adapted for Lorentz microscopy, we find that quantitative magnetic phase reconstructions are possible for defoci distances ranging between approximately 200 μm and 800 μm. The lower limit originates from competing sources of image intensity variations in Fresnel-contrast images, namely structural defects and diffraction contrast. The upper defocus limit is due to a numerical error in the estimation of the intensity derivative based on three images. For magnetic domains, we show quantitative reconstructions of the product of the magnetic induction vector and thickness in element sizes down to approximately 100 nm in lateral size and 5 nm thick resulting in a minimal detection of 5 T nm. Three types of magnetic structures are tested in terms of phase reconstruction: vortex cores, domain walls, and element edges. We quantify vortex core structures at a diameter of 12 nm while the structures of domain walls and element edges are characterized qualitatively. Finally, we show by image simulations that the conclusions of this experimental study are relevant to other Lorentz TEM in which spherical aberration and defocus are dominant aberrations. - Highlights: • Testing TIE for quantitative magnetic phase reconstruction in Lorentz TEM. • Quantitative magnetic phase reconstructions for defoci distances in 200–800 μm range. • Minimal detection of the product of the magnetic induction and thickness is 5 T nm. • Quantitative phase reconstruction for vortex core structures at 12 nm diameter. • Observations

  5. An efficient reconstruction algorithm for differential phase-contrast tomographic images from a limited number of views

    Energy Technology Data Exchange (ETDEWEB)

    Sunaguchi, Naoki [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Yuasa, Tetsuya [Graduate School of Engineering and Science, Yamagata University, Yonezawa, Yamagata 992-8510 (Japan); Gupta, Rajiv [Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States); Ando, Masami [Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba 278-8510 (Japan)

    2015-12-21

    The main focus of this paper is reconstruction of tomographic phase-contrast image from a set of projections. We propose an efficient reconstruction algorithm for differential phase-contrast computed tomography that can considerably reduce the number of projections required for reconstruction. The key result underlying this research is a projection theorem that states that the second derivative of the projection set is linearly related to the Laplacian of the tomographic image. The proposed algorithm first reconstructs the Laplacian image of the phase-shift distribution from the second-derivative of the projections using total variation regularization. The second step is to obtain the phase-shift distribution by solving a Poisson equation whose source is the Laplacian image previously reconstructed under the Dirichlet condition. We demonstrate the efficacy of this algorithm using both synthetically generated simulation data and projection data acquired experimentally at a synchrotron. The experimental phase data were acquired from a human coronary artery specimen using dark-field-imaging optics pioneered by our group. Our results demonstrate that the proposed algorithm can reduce the number of projections to approximately 33% as compared with the conventional filtered backprojection method, without any detrimental effect on the image quality.

  6. Fully automated, high speed, tomographic phase object reconstruction using the transport of intensity equation in transmission and reflection configurations.

    Science.gov (United States)

    Nguyen, Thanh; Nehmetallah, George; Tran, Dat; Darudi, Ahmad; Soltani, Peyman

    2015-12-10

    While traditional transport of intensity equation (TIE) based phase retrieval of a phase object is performed through axial translation of the CCD, in this work a tunable lens TIE is employed in both transmission and reflection configurations. These configurations are extended to a 360° tomographic 3D reconstruction through multiple illuminations from different angles by a custom fabricated rotating assembly of the phase object. Synchronization circuitry is developed to control the CCD camera and the Arduino board, which in its turn controls the tunable lens and the stepper motor to automate the tomographic reconstruction process. Finally, a MATLAB based user friendly graphical user interface is developed to control the whole system and perform tomographic reconstruction using both multiplicative and inverse radon based techniques.

  7. Cosmic flows and the expansion of the Local Universe from nonlinear phase-space reconstructions

    CERN Document Server

    Hess, Steffen

    2014-01-01

    We investigate the impact of cosmic flows and density perturbations on Hubble constant $H_0$ measurements using nonlinear phase-space reconstructions of the Local Universe (LU). We rely on a set of 25 N-body simulations which are constrained to resemble the LU within distances of about 90 Mpc/h. These have been randomly extended up to volumes enclosing distances of 360 Mpc/h with augmented Lagrangian perturbation theory (=750 simulations), accounting in this way for effects from from larger scales ($\\sigma_{\\rm large}=134$ km/s). We report on Local Group (LG) speed reconstructions, which are compatible with those derived from the CMB-dipole: $|v_{\\rm LG}|=685\\pm137$ km/s. The direction $(l,b)=(260.5\\pm 13.3,39.1\\pm 10.4)^\\circ$ is found to be compatible with observations. We use the CMB-dipole information to estimate the missing large scale bulk flow component, indicating that we miss a closely perpendicular flow with a magnitude corresponding to $1.4 \\sigma_{\\rm large}$. Considering this, our bulk flow estim...

  8. Phase and amplitude wave front sensing and reconstruction with a modified plenoptic camera

    Science.gov (United States)

    Wu, Chensheng; Ko, Jonathan; Nelson, William; Davis, Christopher C.

    2014-10-01

    A plenoptic camera is a camera that can retrieve the direction and intensity distribution of light rays collected by the camera and allows for multiple reconstruction functions such as: refocusing at a different depth, and for 3D microscopy. Its principle is to add a micro-lens array to a traditional high-resolution camera to form a semi-camera array that preserves redundant intensity distributions of the light field and facilitates back-tracing of rays through geometric knowledge of its optical components. Though designed to process incoherent images, we found that the plenoptic camera shows high potential in solving coherent illumination cases such as sensing both the amplitude and phase information of a distorted laser beam. Based on our earlier introduction of a prototype modified plenoptic camera, we have developed the complete algorithm to reconstruct the wavefront of the incident light field. In this paper the algorithm and experimental results will be demonstrated, and an improved version of this modified plenoptic camera will be discussed. As a result, our modified plenoptic camera can serve as an advanced wavefront sensor compared with traditional Shack- Hartmann sensors in handling complicated cases such as coherent illumination in strong turbulence where interference and discontinuity of wavefronts is common. Especially in wave propagation through atmospheric turbulence, this camera should provide a much more precise description of the light field, which would guide systems in adaptive optics to make intelligent analysis and corrections.

  9. Online monitoring of gas-solid two-phase flow using projected CG method in ECT image reconstruction

    Institute of Scientific and Technical Information of China (English)

    Qi wang; Chengyi Yang; Huaxiang Wang; Ziqiang Cui; Zhentao Gao

    2013-01-01

    Electrical capacitance tomography (ECT) is a promising technique for multi-phase flow measurement due to its high speed,low cost and non-intrusive sensing.Image reconstruction for ECT is an inverse problem of finding the permittivity distribution of an object by measuring the electrical capacitances between sets of electrodes placed around its periphery.The conjugate gradient (CG) method is a popular image reconstruction method for ECT,in spite of its low convergence rate.In this paper,an advanced version of the CG method,the projected CG method,is used for image reconstruction of an ECT system.The solution space is projected into the Krylov subspace and the inverse problem is solved by the CG method in a low-dimensional specific subspace.Both static and dynamic experiments were carried out for gas-solid two-phase flows.The flow regimes are identified using the reconstructed images obtained with the projected CG method.The results obtained indicate that the projected CG method improves the quality of reconstructed images and dramatically reduces computation time,as compared to the traditional sensitivity,Landweber,and CG methods.Furthermore,the projected CG method was also used to estimate the important parameters of the pneumatic conveying process,such as the volume concentration,flow velocity and mass flow rate of the solid phase.Therefore,the projected CG method is considered suitable for online gas-solid two-phase flow measurement.

  10. Image reconstruction in phase-contrast tomography exploiting the second-order statistical properties of the projection data.

    Science.gov (United States)

    Chou, Cheng-Ying; Huang, Pin-Yu

    2011-11-21

    X-ray phase-contrast tomography (PCT) methods seek to quantitatively reconstruct separate images that depict an object's absorption and refractive contrasts. Most PCT reconstruction algorithms generally operate by explicitly or implicitly performing the decoupling of the projected absorption and phase properties at each tomographic view angle by use of a phase-retrieval formula. However, the presence of zero-frequency singularity in the Fourier-based phase retrieval formulas will lead to a strong noise amplification in the projection estimate and the subsequent refractive image obtained using conventional algorithms like filtered backprojection (FBP). Tomographic reconstruction by use of statistical methods can account for the noise model and a priori information, and thereby can produce images with better quality over conventional filtered backprojection algorithms. In this work, we demonstrate an iterative image reconstruction method that exploits the second-order statistical properties of the projection data can mitigate noise amplification in PCT. The autocovariance function of the reconstructed refractive images was empirically computed and shows smaller and shorter noise correlation compared to those obtained using the FBP and unweighted penalized least-squares methods. Concepts from statistical decision theory are applied to demonstrate that the statistical properties of images produced by our method can improve signal detectability.

  11. Air pathway report: Phase I of the Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    1991-07-01

    Phase 1 of the air-pathway portion of the Hanford Environmental Dose Reconstruction (HEDR) Project sought to determine whether dose estimates could be calculated for populations in the 10 counties nearest the Hanford Site from atmospheric releases of iodine-131 from the site from 1944--1947. Phase 1 demonstrated the following: HEDR-calculated source-term estimates of iodine-131 releases to the atmosphere were within 20% of previously published estimates; calculated vegetation concentrations of iodine-131 agree well with previously published measurements; the highest of the Phase 1 preliminary dose estimates to the thyroid are consistent with independent, previously published estimates of doses to maximally exposed individuals; and, relatively crude, previously published measurements of thyroid burdens for Hanford workers are in the range of average burdens that the HEDR model estimated for similar reference individuals'' for the period 1944--1947. Preliminary median dose estimates summed over the year 1945--1947 for the primary pathway, air-pasture-cow-milk-thyroid, ranged from low median values of 0.006 rad for upwind adults who obtained milk from backyard cows not on pasture to high median values of 68.0 rad for downwind infants who drank milk from pasture-fed cows. Extremes of the estimated range are a low of essentially zero to upwind adults and a high of almost 3000 rem to downwind infants. 37 refs., 37 figs., 2 tabs.

  12. A reconstruction method for cone-beam differential x-ray phase-contrast computed tomography.

    Science.gov (United States)

    Fu, Jian; Velroyen, Astrid; Tan, Renbo; Zhang, Junwei; Chen, Liyuan; Tapfer, Arne; Bech, Martin; Pfeiffer, Franz

    2012-09-10

    Most existing differential phase-contrast computed tomography (DPC-CT) approaches are based on three kinds of scanning geometries, described by parallel-beam, fan-beam and cone-beam. Due to the potential of compact imaging systems with magnified spatial resolution, cone-beam DPC-CT has attracted significant interest. In this paper, we report a reconstruction method based on a back-projection filtration (BPF) algorithm for cone-beam DPC-CT. Due to the differential nature of phase contrast projections, the algorithm restrains from differentiation of the projection data prior to back-projection, unlike BPF algorithms commonly used for absorption-based CT data. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured with a three-grating interferometer and a micro-focus x-ray tube source. Moreover, the numerical simulation and experimental results demonstrate that the proposed method can deal with several classes of truncated cone-beam datasets. We believe that this feature is of particular interest for future medical cone-beam phase-contrast CT imaging applications.

  13. Classification of power quality combined disturbances based on phase space reconstruction and support vector machines

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Power Quality (PQ) combined disturbances become common along with ubiquity of voltage flickers and harmonics. This paper presents a novel approach to classify the different patterns of PQ combined disturbances. The classification system consists of two parts, namely the feature extraction and the automatic recognition. In the feature extraction stage, Phase Space Reconstruction (PSR), a time series analysis tool, is utilized to construct disturbance signal trajectories. For these trajectories, several indices are proposed to form the feature vectors. Support Vector Machines (SVMs) are then implemented to recognize the different patterns and to evaluate the efficiencies. The types of disturbances discussed include a combination of short-term disturbances (voltage sags, swells) and long-term disturbances (flickers, harmonics), as well as their homologous single ones. The feasibilities of the proposed approach are verified by simulation with thousands of PQ events. Comparison studies based on Wavelet Transform (WT) and Artificial Neural Network (ANN) are also reported to show its advantages.

  14. Numerical Simulation of Two Phase Flow in Reconstructed Pore Network Based on Lattice Boltzmann Method

    Directory of Open Access Journals (Sweden)

    Song Rui

    2013-01-01

    Full Text Available Accurate prediction and understanding of the disorder microstructures in the porous media contribute to acquiring the macroscopic physical properties such as conductivity, permeability, formation factor, elastic moduli etc. Based on the rock serial sectioning images of Berea sandstone acquired by the core scanning system developed by our research group, the reconstructed rock model is established in the Mimics software and the extracted pore network of the porous rock is accomplished by the self-programming software in C++ programming language based on the revised Medial axis based algorithm and the Maximal ball algorithm. Using a lattice Boltzmann method, the single and two C phase flow are accomplished. Both of the pore-scale networks and the seepage mechanism of the single- and two Cphase flow are identical with the benchmark experimental data.

  15. On the definition of laser threshold of nanoscale lasers by phase space reconstruction

    CERN Document Server

    Xavier, Hachair; Lippi, Gian-Lucca; David, Elvira; Gratiet, Luc Le; Lemaître, Aristide; Izo, Abram; Sagnes, Isabelle; Robert-Philip, Isabelle; Beveratos, Alexios

    2010-01-01

    Nanoscale lasers sustain few optical modes and contain few emitting dipoles, in contrast to macroscopic lasers. Due to the strong confinement, the fraction of spontaneous emission $\\beta$ funneled into the useful mode is high (of the order of few 10$^{-1}$) and the threshold defined as an abrupt kink in the light in- light out curve becomes ill-defined. Alternative definitions based on photon statistics have been proposed to define the onset of stimulated emission in such light sources. In this paper, we propose a definition based on an analysis of the laser dynamics by reconstructing laser trajectories in phase space as a function of excitation power. Threshold is unambiguously defined by a change in the trajectory's shape and in the area contained inside the trajectory. This change is shown theoretically and subsequently observed experimentally in photonic crystal lasers.

  16. Terahertz in-line digital holography of dragonfly hindwing: amplitude and phase reconstruction at enhanced resolution by extrapolation.

    Science.gov (United States)

    Rong, Lu; Latychevskaia, Tatiana; Wang, Dayong; Zhou, Xun; Huang, Haochong; Li, Zeyu; Wang, Yunxin

    2014-07-14

    We report here on terahertz (THz) digital holography on a biological specimen. A continuous-wave (CW) THz in-line holographic setup was built based on a 2.52 THz CO(2) pumped THz laser and a pyroelectric array detector. We introduced novel statistical method of obtaining true intensity values for the pyroelectric array detector's pixels. Absorption and phase-shifting images of a dragonfly's hindwing were reconstructed simultaneously from single in-line hologram. Furthermore, we applied phase retrieval routines to eliminate twin image and enhanced the resolution of the reconstructions by hologram extrapolation beyond the detector area. The finest observed features are 35 μm width cross veins.

  17. Object-wave reconstruction by carbon film-based Zernike- and Hilbert-phase plate microscopy: A theoretical study not restricted to weak-phase objects

    Energy Technology Data Exchange (ETDEWEB)

    Dries, M., E-mail: manuel.dries@kit.edu [Laboratorium fuer Elektronenmikroskopie, Karlsruher Institut fuer Technologie (KIT), D-76128 Karlsruhe (Germany); Schultheiss, K.; Gamm, B. [Laboratorium fuer Elektronenmikroskopie, Karlsruher Institut fuer Technologie (KIT), D-76128 Karlsruhe (Germany); Rosenauer, A. [Institut fuer Festkoerperphysik, Universitaet Bremen, D-28359 Bremen (Germany); Schroeder, R.R. [BioQuant CellNetworks, Universitaet Heidelberg, D-69120 Heidelberg (Germany); Gerthsen, D. [Laboratorium fuer Elektronenmikroskopie, Karlsruher Institut fuer Technologie (KIT), D-76128 Karlsruhe (Germany)

    2011-01-15

    Transmission electron microscopy phase-contrast images taken by amorphous carbon film-based phase plates are affected by the scattering of electrons within the carbon film causing a modification of the image-wave function. Moreover, image artefacts are produced by non-centrosymmetric phase plate designs such as the Hilbert-phase plate. Various methods are presented to correct phase-contrast images with respect to the scattering of electrons and image artefacts induced by phase plates. The proposed techniques are not restricted to weak-phase objects and linear image formation. Phase-contrast images corrected by the presented methods correspond to those taken by an ideal centrosymmetric, matter-free phase plate and are suitable for object-wave reconstruction. -- Research Highlights: {yields} Object-wave reconstruction by phase plates considering nonlinear image formation. {yields} Requirement of three (five) images in case of Zernike- (Hilbert-) phase plates. {yields} Analytical correction of damping and/or image artefacts induced by phase plates.{yields} Validation by simulation of crystalline silicon.

  18. Critical surface phase of α2(2 × 4) reconstructed zig-zag chains on InAs(001)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xiang [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); Zhou, Xun [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); School of Physics and Electronics Science, Guizhou Normal University, Guizhou, Guiyang 550001 (China); Wang, Ji-Hong [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); Luo, Zi-Jiang [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); School of Education Administration, Guizhou University of Finance and Economics, Guizhou, Guiyang 550004 (China); Zhou, Qing; Liu, Ke; Hu, Ming-Zhe [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); Ding, Zhao, E-mail: zding@gzu.edu.cn [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China)

    2014-07-01

    The critical condition for InAs(001) surface phase transition has been studied, the surface phase transition of InAs(001) showed discontinuity with hysteresis cycle as a function of substrate temperature. A mixed reconstruction surface and zig-zag chain α2(2 × 4) reconstruction surface have been observed by scanning tunneling microscopy. Considering the interaction and dynamics of surface arsenic atoms, the zig-zag chains of α2(2 × 4) reconstruction were found to be actually caused by the selective adsorption and desorption of surface arsenic dimers, they played a critical role in the surface phase transition between (2 × 4) and (4 × 2). - Highlights: • Discontinuous surface phase transition phenomena on the flat InAs(001) surface • Nanoscale InAs(001) surface observed by scanning tunneling microscopy • “Zig-Zag” chains of α2(2 × 4) reconstruction • Critical role in the surface phase transition between (2 × 4) and (4 × 2)

  19. Sulfur isotope analysis of cinnabar from Roman wall paintings by elemental analysis/isotope ratio mass spectrometry--tracking the origin of archaeological red pigments and their authenticity.

    Science.gov (United States)

    Spangenberg, Jorge E; Lavric, Jost V; Meisser, Nicolas; Serneels, Vincent

    2010-10-15

    The most valuable pigment of the Roman wall paintings was the red color obtained from powdered cinnabar (Minium Cinnabaris pigment), the red mercury sulfide (HgS), which was brought from mercury (Hg) deposits in the Roman Empire. To address the question of whether sulfur isotope signatures can serve as a rapid method to establish the provenance of the red pigment in Roman frescoes, we have measured the sulfur isotope composition (δ(34)S value in ‰ VCDT) in samples of wall painting from the Roman city Aventicum (Avenches, Vaud, Switzerland) and compared them with values from cinnabar from European mercury deposits (Almadén in Spain, Idria in Slovenia, Monte Amiata in Italy, Moschellandsberg in Germany, and Genepy in France). Our study shows that the δ(34)S values of cinnabar from the studied Roman wall paintings fall within or near to the composition of Almadén cinnabar; thus, the provenance of the raw material may be deduced. This approach may provide information on provenance and authenticity in archaeological, restoration and forensic studies of Roman and Greek frescoes.

  20. Dynamic analysis of heartbeat rate signals of epileptics using multidimensional phase space reconstruction approach

    Science.gov (United States)

    Su, Zhi-Yuan; Wu, Tzuyin; Yang, Po-Hua; Wang, Yeng-Tseng

    2008-04-01

    The heartbeat rate signal provides an invaluable means of assessing the sympathetic-parasympathetic balance of the human autonomic nervous system and thus represents an ideal diagnostic mechanism for detecting a variety of disorders such as epilepsy, cardiac disease and so forth. The current study analyses the dynamics of the heartbeat rate signal of known epilepsy sufferers in order to obtain a detailed understanding of the heart rate pattern during a seizure event. In the proposed approach, the ECG signals are converted into heartbeat rate signals and the embedology theorem is then used to construct the corresponding multidimensional phase space. The dynamics of the heartbeat rate signal are then analyzed before, during and after an epileptic seizure by examining the maximum Lyapunov exponent and the correlation dimension of the attractors in the reconstructed phase space. In general, the results reveal that the heartbeat rate signal transits from an aperiodic, highly-complex behaviour before an epileptic seizure to a low dimensional chaotic motion during the seizure event. Following the seizure, the signal trajectories return to a highly-complex state, and the complex signal patterns associated with normal physiological conditions reappear.

  1. EEMD Independent Extraction for Mixing Features of Rotating Machinery Reconstructed in Phase Space

    Directory of Open Access Journals (Sweden)

    Zaichao Ma

    2015-04-01

    Full Text Available Empirical Mode Decomposition (EMD, due to its adaptive decomposition property for the non-linear and non-stationary signals, has been widely used in vibration analyses for rotating machinery. However, EMD suffers from mode mixing, which is difficult to extract features independently. Although the improved EMD, well known as the ensemble EMD (EEMD, has been proposed, mode mixing is alleviated only to a certain degree. Moreover, EEMD needs to determine the amplitude of added noise. In this paper, we propose Phase Space Ensemble Empirical Mode Decomposition (PSEEMD integrating Phase Space Reconstruction (PSR and Manifold Learning (ML for modifying EEMD. We also provide the principle and detailed procedure of PSEEMD, and the analyses on a simulation signal and an actual vibration signal derived from a rubbing rotor are performed. The results show that PSEEMD is more efficient and convenient than EEMD in extracting the mixing features from the investigated signal and in optimizing the amplitude of the necessary added noise. Additionally PSEEMD can extract the weak features interfered with a certain amount of noise.

  2. Cinnabar and realgar in traditional chinese medicines:remedies or poisons?%含朱砂、雄黄的中成药,是药还是毒?

    Institute of Scientific and Technical Information of China (English)

    刘杰; 陆远富; 时京珍; 张锋; 吴芹

    2011-01-01

    朱砂(96% HgS)和雄黄(90% As4S4)与其它中药配伍应用于临床已有上千年历史.但由于朱砂含汞,雄黄含砷,其安全性近年来引起了越来越多的关注.一般认为把已知的金属毒物用于医药中不可取,但也有不同的意见认为朱砂和雄黄有长期用药历史,临床有效,其毒副作用可耐受.含朱砂、雄黄的中药是药还是毒?本文就含朱砂和雄黄的中成药的研究进展作一综述,并提出(1)以总砷和总汞为标准进行评价含朱砂、雄黄中药的安全性不妥,(2)朱砂和雄黄的用药量和用药时间决定其毒性反应,(3)朱砂和雄黄是中药复方中的有效成分之一,应作深入研究来决定其取舍.%Cinnabar( 96 % of HgS)and realgar( 90 % of As4S4)have been used in traditional Chinese medicines for thousands of years.Both mercury ( Hg) and arsenic ( As)are well-known toxic substances and the safety of cinnabar-and realgar-containing traditional Chinese medicines is of concern.It is presumed that any intentional use of known toxic metals in medicine is an unacceptable risk,hut an opposing opinion holds that cinnabar and realgar have a long history of clear pharmacological utility with tolerable side effects.Are cinnabar-and/or realgar-containing Chinese medicines remedies or poisons? This chapter summarizes recent progress of toxicological and pharmacological studies on this issue and highlights that( 1 ) the use of total Hg and As for risk evaluation of cinnabar and realgar is inappropriate,(2) the right dose and duration of cinnabar and realer administration differentiate a remedy from a poison,and( 3 )cinnabar and realgar are active ingredients in Chinese medicines.The well-designed studies are needed to support or to reject their existence in traditional remedies.

  3. A compressed sensing based reconstruction algorithm for synchrotron source propagation-based X-ray phase contrast computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Melli, Seyed Ali, E-mail: sem649@mail.usask.ca [Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, SK (Canada); Wahid, Khan A. [Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, SK (Canada); Babyn, Paul [Department of Medical Imaging, University of Saskatchewan, Saskatoon, SK (Canada); Montgomery, James [College of Medicine, University of Saskatchewan, Saskatoon, SK (Canada); Snead, Elisabeth [Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK (Canada); El-Gayed, Ali [College of Medicine, University of Saskatchewan, Saskatoon, SK (Canada); Pettitt, Murray; Wolkowski, Bailey [College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK (Canada); Wesolowski, Michal [Department of Medical Imaging, University of Saskatchewan, Saskatoon, SK (Canada)

    2016-01-11

    Synchrotron source propagation-based X-ray phase contrast computed tomography is increasingly used in pre-clinical imaging. However, it typically requires a large number of projections, and subsequently a large radiation dose, to produce high quality images. To improve the applicability of this imaging technique, reconstruction algorithms that can reduce the radiation dose and acquisition time without degrading image quality are needed. The proposed research focused on using a novel combination of Douglas–Rachford splitting and randomized Kaczmarz algorithms to solve large-scale total variation based optimization in a compressed sensing framework to reconstruct 2D images from a reduced number of projections. Visual assessment and quantitative performance evaluations of a synthetic abdomen phantom and real reconstructed image of an ex-vivo slice of canine prostate tissue demonstrate that the proposed algorithm is competitive in reconstruction process compared with other well-known algorithms. An additional potential benefit of reducing the number of projections would be reduction of time for motion artifact to occur if the sample moves during image acquisition. Use of this reconstruction algorithm to reduce the required number of projections in synchrotron source propagation-based X-ray phase contrast computed tomography is an effective form of dose reduction that may pave the way for imaging of in-vivo samples.

  4. 3D algebraic iterative reconstruction for cone-beam x-ray differential phase-contrast computed tomography.

    Science.gov (United States)

    Fu, Jian; Hu, Xinhua; Velroyen, Astrid; Bech, Martin; Jiang, Ming; Pfeiffer, Franz

    2015-01-01

    Due to the potential of compact imaging systems with magnified spatial resolution and contrast, cone-beam x-ray differential phase-contrast computed tomography (DPC-CT) has attracted significant interest. The current proposed FDK reconstruction algorithm with the Hilbert imaginary filter will induce severe cone-beam artifacts when the cone-beam angle becomes large. In this paper, we propose an algebraic iterative reconstruction (AIR) method for cone-beam DPC-CT and report its experiment results. This approach considers the reconstruction process as the optimization of a discrete representation of the object function to satisfy a system of equations that describes the cone-beam DPC-CT imaging modality. Unlike the conventional iterative algorithms for absorption-based CT, it involves the derivative operation to the forward projections of the reconstructed intermediate image to take into account the differential nature of the DPC projections. This method is based on the algebraic reconstruction technique, reconstructs the image ray by ray, and is expected to provide better derivative estimates in iterations. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured with a three-grating interferometer and a mini-focus x-ray tube source. It is shown that the proposed method can reduce the cone-beam artifacts and performs better than FDK under large cone-beam angles. This algorithm is of interest for future cone-beam DPC-CT applications.

  5. Following a photoinduced reconstructive phase transformation and its influence on the crystal integrity: powder diffraction and theoretical study.

    Science.gov (United States)

    Runčevski, Tomče; Blanco-Lomas, Marina; Marazzi, Marco; Cejuela, Marcos; Sampedro, Diego; Dinnebier, Robert E

    2014-06-23

    In the course of solid-state photoreactions, a single crystal (SC) of the reactant can be transformed into an SC of the product or it can lose crystallinity and become amorphous. In-between these two scenarios exist the reconstructive phase transformations, where upon irradiation, the reactant SC becomes a powder or an SC with increased mosaicity. We present a detailed description of reconstructive photodimerization, where the structural changes are directly correlated with the disintegration process. The kinetics of the reaction is explained by two kinetic regimes, forming an autocatalytic autoinhibition photoreaction set with high quantum yield. In addition, the photoreaction pathways were studied theoretically.

  6. Memory effect of activated Mg-Al hydrotalcite: in situ XRD studies during decomposition and gas-phase reconstruction.

    Science.gov (United States)

    Pérez-Ramírez, Javier; Abelló, Sònia; van der Pers, Niek M

    2007-01-01

    The thermal decomposition of Mg-Al hydrotalcite and the subsequent reconstruction of the decomposed products in the presence of water vapor (2 vol. % H(2)O in N(2)) have been investigated by in situ XRD. Thermographic analysis and temperature-programmed desorption MS results complemented the diffraction data. Valuable mechanistic and kinetic insights into these processes, which are of prime importance for optimal activation of this type of material for catalytic applications, were obtained. Hydrotalcite decomposition to the mixed oxide proceeds via formation at 423-473 K of an intermediate phase, consisting of a highly disordered, dehydrated, layered structure. The latter evolves by removal of interlayer water on heating, causing a shrinking of the interlayer space (it is up to 45 % smaller than in the as-synthesized hydrotalcite). Above 623 K, Mg(Al)O(x) oxide with the periclase structure is formed. Reversion of the intermediate dehydrated structure to hydrotalcite upon contact with water vapor is complete and very fast at room temperature. Recovery of hydrotalcite from the oxide calcined at 723 K is two orders of magnitude slower than rehydration of the intermediate layered structure and one order of magnitude slower than the typically practiced liquid-phase reconstruction. In contrast to the decomposition, the reconstruction mechanism does not involve an intermediate phase. The gas-phase rehydration and reconstruction was interrupted above 303 K. This is attributed to the poor wetting of the surface of the decomposed materials induced by hampered H(2)O adsorption above room temperature at the water vapor pressure applied. The Avrami-Erofe'ev model describes the reconstruction kinetics well.

  7. Reconstructed animation from four-phase grip MRI of the wrist with ulnar-sided pain.

    Science.gov (United States)

    Oda, T; Wada, T; Iba, K; Aoki, M; Tamakawa, M; Yamashita, T

    2013-09-01

    In order to visualize dynamic variations related to ulnar-sided wrist pain, animation was reconstructed from T2* coronal-sectioned magnetic resonance imaging in each of the four phases of grip motion for nine wrists in patients with ulnar pain. Eight of the nine wrists showed a positive ulnar variance of less than 2 mm. Ulnocarpal impaction and triangular fibrocartilage complex injury were assessed on the basis of animation and arthroscopy, respectively. Animation revealed ulnocarpal impaction in four wrists. In one of the four wrists, the torn portion of the articular disc was impinged between the ulnar head and ulnar proximal side of the lunate. In another wrist, the ulnar head impacted the lunate directly through the defect in the articular disc that had previously been excised. An ulnar shortening osteotomy successfully relieved ulnar wrist pain in all four cases with both ulnocarpal impaction and Palmer's Class II triangular fibrocartilage complex tears. This method demonstrated impairment of the articular disc and longitudinal instability of the distal radioulnar joint simultaneously and should be of value in investigating dynamic pathophysiology causing ulnar wrist pain.

  8. Mechanism of Mineral Phase Reconstruction for Improving the Beneficiation of Copper and Iron from Copper Slag

    Science.gov (United States)

    Guo, Zhengqi; Zhu, Deqing; Pan, Jan; Zhang, Feng

    2016-09-01

    To maximize the recovery of iron and copper from copper slag, the modification process by adding a compound additive (a mixture of hematite, pyrite and manganous oxide) and optimizing the cooling of the slag was studied. The phase reconstruction mechanism of the slag modification process was revealed by thermodynamic calculations, x-ray diffraction, optical microscopy and scanning electron microscopy. The results show that the synergy between the burnt lime and the compound additive promotes the generation of target minerals, such as magnetite and copper matte. In addition, the multifunctional compound additive is able to improve the fluidity of the molten slag, which facilitates the coalescence and growth of fine particles of the target minerals. As a result, the percentage of iron distributed in the form of magnetite increased from 32.9% to 65.1%, and that of the copper exiting in the form of metallic copper and copper sulfide simultaneously increased from 80.0% to 90.3%. Meanwhile, the grains of the target minerals in the modified slag grew markedly to a mean size of over 50 μm after slow cooling. Ultimately, the beneficiation efficiency of copper and iron was improved because of the ease with which the target minerals could be liberated.

  9. Selection of dominant radionuclides for Phase 1 of the Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Napier, B.A.

    1991-07-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation dose that individuals could have received as a result of emissions from nuclear operations at Hanford since their inception in 1944. A vital step in the estimation of radiation doses is the determination of the source term,'' that is, the quantities of radionuclides that were released to the environment from the various Hanford operations. Hanford operations have at various times involved hundreds of different radionuclides, some in relatively large quantities. Those radionuclides present in the largest quantities, although significant from an operational handling point of view, may not necessarily have been those of greatest concern for offsite radiation dose. This report documents the selection of the dominant radionuclides (those that may have resulted in the largest portion of the received doses) in the source term for Phase 1 of the HEDR Project, that is, for atmospheric releases from 1944 through 1947 and for surface water releases from 1964 through 1966. 15 refs., 3 figs., 10 tabs.

  10. River flow forecasting: use of phase-space reconstruction and artificial neural networks approaches

    Science.gov (United States)

    Sivakumar, B.; Jayawardena, A. W.; Fernando, T. M. K. G.

    2002-08-01

    The use of two non-linear black-box approaches, phase-space reconstruction (PSR) and artificial neural networks (ANN), for forecasting river flow dynamics is studied and a comparison of their performances is made. This is done by attempting 1-day and 7-day ahead forecasts of the daily river flow from the Nakhon Sawan station at the Chao Phraya River basin in Thailand. The results indicate a reasonably good performance of both approaches for both 1-day and 7-day ahead forecasts. However, the performance of the PSR approach is found to be consistently better than that of ANN. One reason for this could be that in the PSR approach the flow series in the phase-space is represented step by step in local neighborhoods, rather than a global approximation as is done in ANN. Another reason could be the use of the multi-layer perceptron (MLP) in ANN, since MLPs may not be most appropriate for forecasting at longer lead times. The selection of training set for the ANN may also contribute to such results. A comparison of the optimal number of variables for capturing the flow dynamics, as identified by the two approaches, indicates a large discrepancy in the case of 7-day ahead forecasts (1 and 7 variables, respectively), though for 1-day ahead forecasts it is found to be consistent (3 variables). A possible explanation for this could be the influence of noise in the data, an observation also made from the 1-day ahead forecast results using the PSR approach. The present results lead to observation on: (1) the use of other neural networks for runoff forecasting, particularly at longer lead times; (2) the influence of training set used in the ANN; and (3) the effect of noise on forecast accuracy, particularly in the PSR approach.

  11. GPU-based rapid reconstruction of cellular 3D refractive index maps from tomographic phase microscopy (Conference Presentation)

    Science.gov (United States)

    Dardikman, Gili; Shaked, Natan T.

    2016-03-01

    We present highly parallel and efficient algorithms for real-time reconstruction of the quantitative three-dimensional (3-D) refractive-index maps of biological cells without labeling, as obtained from the interferometric projections acquired by tomographic phase microscopy (TPM). The new algorithms are implemented on the graphic processing unit (GPU) of the computer using CUDA programming environment. The reconstruction process includes two main parts. First, we used parallel complex wave-front reconstruction of the TPM-based interferometric projections acquired at various angles. The complex wave front reconstructions are done on the GPU in parallel, while minimizing the calculation time of the Fourier transforms and phase unwrapping needed. Next, we implemented on the GPU in parallel the 3-D refractive index map retrieval using the TPM filtered-back projection algorithm. The incorporation of algorithms that are inherently parallel with a programming environment such as Nvidia's CUDA makes it possible to obtain real-time processing rate, and enables high-throughput platform for label-free, 3-D cell visualization and diagnosis.

  12. Accelerated three-dimensional cine phase contrast imaging using randomly undersampled echo planar imaging with compressed sensing reconstruction.

    Science.gov (United States)

    Basha, Tamer A; Akçakaya, Mehmet; Goddu, Beth; Berg, Sophie; Nezafat, Reza

    2015-01-01

    The aim of this study was to implement and evaluate an accelerated three-dimensional (3D) cine phase contrast MRI sequence by combining a randomly sampled 3D k-space acquisition sequence with an echo planar imaging (EPI) readout. An accelerated 3D cine phase contrast MRI sequence was implemented by combining EPI readout with randomly undersampled 3D k-space data suitable for compressed sensing (CS) reconstruction. The undersampled data were then reconstructed using low-dimensional structural self-learning and thresholding (LOST). 3D phase contrast MRI was acquired in 11 healthy adults using an overall acceleration of 7 (EPI factor of 3 and CS rate of 3). For comparison, a single two-dimensional (2D) cine phase contrast scan was also performed with sensitivity encoding (SENSE) rate 2 and approximately at the level of the pulmonary artery bifurcation. The stroke volume and mean velocity in both the ascending and descending aorta were measured and compared between two sequences using Bland-Altman plots. An average scan time of 3 min and 30 s, corresponding to an acceleration rate of 7, was achieved for 3D cine phase contrast scan with one direction flow encoding, voxel size of 2 × 2 × 3 mm(3) , foot-head coverage of 6 cm and temporal resolution of 30 ms. The mean velocity and stroke volume in both the ascending and descending aorta were statistically equivalent between the proposed 3D sequence and the standard 2D cine phase contrast sequence. The combination of EPI with a randomly undersampled 3D k-space sampling sequence using LOST reconstruction allows a seven-fold reduction in scan time of 3D cine phase contrast MRI without compromising blood flow quantification.

  13. Application of phase space reconstruction and v-SVR algorithm in predicting displacement of underground engineering surrounding rock

    Institute of Scientific and Technical Information of China (English)

    SHI Chao; CHEN Yi-feng; YU Zhi-xiong; YANG Kun

    2006-01-01

    A new method for predicting the trend of displacement evolution of surrounding rock was presented in this paper. According to the nonlinear characteristics of displacement time series of underground engineering surrounding rock, based on phase space reconstruction theory and the powerful nonlinear mapping ability of support vector machines, the information offered by the time series datum sets was fully exploited and the non-linearity of the displacement evolution system of surrounding rock was well described.The example suggests that the methods based on phase space reconstruction and modified v-SVR algorithm are very accurate, and the study can help to build the displacement forecast system to analyze the stability of underground engineering surrounding rock.

  14. Terahertz in-line digital holography of dragonfly hindwing: amplitude and phase reconstruction at enhanced resolution by extrapolation

    CERN Document Server

    Rong, Lu; Wang, Dayong; Zhou, Xun; Huang, Haochong; Li, Zeyu; Wang, Yunxin

    2014-01-01

    We report here on terahertz (THz) digital holography on a biological specimen. A continuous-wave (CW) THz in-line holographic setup was built based on a 2.52 THz CO2 pumped THz laser and a pyroelectric array detector. We introduced novel statistical method of obtaining true intensity values for the pyroelectric array detector's pixels. Absorption and phase-shifting images of a dragonfly's hind wing were reconstructed simultaneously from single in-line hologram. Furthermore, we applied phase retrieval routines to eliminate twin image and enhanced the resolution of the reconstructions by hologram extrapolation beyond the detector area. The finest observed features are 35 {\\mu}m width cross veins.

  15. Phase reconstruction from velocity-encoded MRI measurements – A survey of sparsity-promoting variational approaches

    KAUST Repository

    Benning, Martin

    2014-01-01

    In recent years there has been significant developments in the reconstruction of magnetic resonance velocity images from sub-sampled k-space data. While showing a strong improvement in reconstruction quality compared to classical approaches, the vast number of different methods, and the challenges in setting them up, often leaves the user with the difficult task of choosing the correct approach, or more importantly, not selecting a poor approach. In this paper, we survey variational approaches for the reconstruction of phase-encoded magnetic resonance velocity images from sub-sampled k-space data. We are particularly interested in regularisers that correctly treat both smooth and geometric features of the image. These features are common to velocity imaging, where the flow field will be smooth but interfaces between the fluid and surrounding material will be sharp, but are challenging to represent sparsely. As an example we demonstrate the variational approaches on velocity imaging of water flowing through a packed bed of solid particles. We evaluate Wavelet regularisation against Total Variation and the relatively recent second order Total Generalised Variation regularisation. We combine these regularisation schemes with a contrast enhancement approach called Bregman iteration. We verify for a variety of sampling patterns that Morozov\\'s discrepancy principle provides a good criterion for stopping the iterations. Therefore, given only the noise level, we present a robust guideline for setting up a variational reconstruction scheme for MR velocity imaging. © 2013 Elsevier Inc. All rights reserved.

  16. Phase reconstruction of digital holography with the peak of the two-dimensional Gabor wavelet transform.

    Science.gov (United States)

    Weng, Jiawen; Zhong, Jingang; Hu, Cuiying

    2009-06-20

    We describe a numerical reconstruction technique for digital holography by means of the two-dimensional Gabor wavelet transform (2D-GWT). Applying the 2D-GWT to digital holography, the object wave can be reconstructed by calculating the wavelet coefficients of the hologram at the peak of the 2D-GWT automatically. At the same time the effect of the zero-order diffraction image and the twin image are eliminated without spatial filtering. Comparing the numerical reconstruction of a holographic image by the analysis of the one-dimensional Gabor wavelet transform (1D-GWT) with the 2D-GWT, we show that the 2D-GWT method is superior to the 1D-GWT method, especially when the fringes of the hologram are not just along the y direction. The theory and the results of a simulation and experiments are shown.

  17. Digital reconstruction based on angular spectrum diffraction with the ridge of wavelet transform in holographic phase-contrast microscopy.

    Science.gov (United States)

    Weng, Jiawen; Zhong, Jiangang; Hu, Cuiying

    2008-12-22

    A numerical reconstruction technique of digital holography based on angular spectrum diffraction by means of the ridge of Gabor wavelet transform (GWT) is presented. Appling the GWT, the object wave can be reconstructed by calculating the wavelet coefficients of the hologram at the ridge of the GWT automatically even if the spectrum of the virtual image is disturbed by the other spectrum. It provides a way to eliminate the effect of the zero-order and the twin-image terms without the spatial filtering. In particular, based on the angular spectrum theory, GWT is applied to the digital holographic phase-contrast microscopy on biological specimens. The theory, the results of a simulation and an experiment of an onion specimen are shown.

  18. Preliminary investigations of equilibrium reconstruction quality during ELMy and ELM-free phases on JET

    Energy Technology Data Exchange (ETDEWEB)

    Gelfusa, M., E-mail: gelfusa@ing.uniroma2.it [Associazione EURATOM-ENEA—University of Rome “Tor Vergata”, Rome (Italy); Murari, A. [Associazione EURATOM-ENEA per la Fusione, Consorzio RFX, 4-35127 Padova (Italy); Peluso, E. [Associazione EURATOM-ENEA sulla Fusione, ENEA C.R. Frascati, C.P. 65, I-00044 Frascati, Rome (Italy); Gaudio, P. [Associazione EURATOM-ENEA—University of Rome “Tor Vergata”, Rome (Italy); Orsitto, F.P. [Associazione EURATOM-ENEA sulla Fusione, ENEA C.R. Frascati, C.P. 65, I-00044 Frascati, Rome (Italy); Gerasimov, S. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Collaboration: JET-EFDA Contributors

    2013-08-21

    On JET, the magnetic topology is normally derived from the code EFIT, which solves the Grad–Shafranov equation with constraints imposed by the available measurements, typically the pick-up coils. Both the code and the measurements are expected to perform worse during ELMs. To assess this hypothesis, various statistical indicators, based on the values of the residuals and their probability distribution, have been calculated. They all show that the quality of EFIT reconstructions is clearly better in absence of ELMs. How the responsibility, for the lower quality of the reconstructions, is shared between the measurements and EFIT is a subject under investigation. © 2001 Elsevier Science. All rights reserved.

  19. A novel reconstruction method based on changes in phase for subsurface large sloped dielectric target using GPR

    Science.gov (United States)

    Zhou, Lijun; Ouyang, Shan; Liao, Guisheng

    2016-11-01

    In ground-penetrating radar (GPR) subsurface target reconstruction, various techniques based on amplitude (or energy) information of echoes from metal target with small size can work well. However, for environmental and geological applications, the quantitative analysis of the target's geometric features, like location, shape and size, is exactly what we are concerned about. Amplitude-based reconstruction method faces challenges in these applications. A large sloped target under the surface may lead to abundant virtual image energy and cause position deviation. In addition, the echoes from the inner part of the penetrable dielectric target may be too weak to be detected. However, changes in phase may highlight the effects of echoes from the target on that from the surroundings, even if the effect is small due to the weak energy. In this paper, a novel method based on changes in phase is proposed to reconstruct subsurface large sloped dielectric target. To remove the virtual image, the main idea is based on the geometric relationship between the recorded signal plotted beneath the receiving antenna and the reflected signal emanated from the target position which is "ahead" or "behind" of the receiving antenna. Furthermore, the electromagnetic (EM) wave propagating through the penetrable target will change its velocity and result in advancing or lagging related to the geometric shape of the target. In this case, the weak echoes from the back surface of the target can be compensated according to the advancing or lagging. With the proposed method, the virtual image is eliminated and both front and back surface of the target are reconstructed. Results from the laboratory experiments demonstrate the validity of the proposed method.

  20. Phase-shifting digital holography in image reconstruction%基于数字移相全息的图像重构

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A phase-shifting digital holography scheme developed to investigate internal defects in artworks is described. Phase-shifting is utilized to obtain a clear reconstructed object wave from a rough surface texture. A reverse-transform algorithm is employed to reconstruct the object wave on its original position of unknown distance or the imaging position from the object wave information on the holographic plane. To get the clearest reconstruction the exact registration of the unknown distance is determined by applying the intensity sum as the auto-focusing function. The spatial resolution of the reconstruction image is also investigated for a variety of affecting factors. Laboratory results of reconstruction images under deformation are presented.

  1. Research on encoding multi-gray-scale phase hologram and wavefront reconstruction.

    Science.gov (United States)

    Zhang, Hongxin; Zhou, Hao; Li, Jingyao; Qiao, Yujing; Gao, Wei

    2016-04-01

    Application of computer-generated holography for wavefront generation is beneficial for optical interferometry and 3D image display. However, there is a noticeable encoding error in computer-generated holograms, which is encoded by using the object's wavefront function in a computer. The encoding error will be transmitted and amplified during fabrication of a hologram, which can cause a reconstructed error in the generated wavefront. A correction method of encoding errors based on the least-squares fitting is proposed. A validating experiment is completed by using a liquid crystal spatial light modulator to reconstruct a group of paraboloid wavefronts. The results show that encoding errors increase the reconstructed error of a wavefront less than optical system errors, and the root-mean-square value drops 0.022λ after the correction of the encoding error, but it falls 0.092λ after the correction of optical system errors. The total error has been reduced by 0.114λ. This research is helpful for prediction of encoding errors and improvement of wavefront reconstruction accuracy.

  2. Traffic dynamics in empirical probe vehicle data studied with three-phase theory: Spatiotemporal reconstruction of traffic phases and generation of jam warning messages

    Science.gov (United States)

    Kerner, Boris S.; Rehborn, Hubert; Schäfer, Ralf-Peter; Klenov, Sergey L.; Palmer, Jochen; Lorkowski, Stefan; Witte, Nikolaus

    2013-01-01

    Empirical and theoretical analyses of the spatiotemporal dynamics of traffic flow reconstructed from randomly distributed probe vehicle data are presented. For the empirical analysis, probe vehicle data generated by TomTom’s navigation devices in the commercial TomTom’s HD-traffic service as well as road detector data measured at the same road section are used. A stochastic microscopic (car-following) three-phase model is further developed for simulations of a real empirical complex spatiotemporal traffic dynamics measured over a three-lane long road stretch with several different bottlenecks. Physical features and limitations of simulations of real spatiotemporal traffic dynamics are revealed. Phase transition points between free flow (F), synchronized flow (S), and wide moving jam (J) are identified along trajectories of empirical and simulated probe vehicles randomly distributed in traffic flow. As predicted by three-phase theory, the empirical probe vehicle data shows that traffic breakdown is an F→S transition and wide moving jams emerge only in synchronized flow, i.e., due to S→J transitions. Through the use of the simulations, it has been found that already about 2% of probe vehicle data allows us to reconstruct traffic dynamics in space and time with an accuracy that is high enough for most applications like the generation of jam warning messages studied in the article.

  3. Analysis and accurate reconstruction of incomplete data in X-ray differential phase-contrast computed tomography.

    Science.gov (United States)

    Fu, Jian; Tan, Renbo; Chen, Liyuan

    2014-01-01

    X-ray differential phase-contrast computed tomography (DPC-CT) is a powerful physical and biochemical analysis tool. In practical applications, there are often challenges for DPC-CT due to insufficient data caused by few-view, bad or missing detector channels, or limited scanning angular range. They occur quite frequently because of experimental constraints from imaging hardware, scanning geometry, and the exposure dose delivered to living specimens. In this work, we analyze the influence of incomplete data on DPC-CT image reconstruction. Then, a reconstruction method is developed and investigated for incomplete data DPC-CT. It is based on an algebraic iteration reconstruction technique, which minimizes the image total variation and permits accurate tomographic imaging with less data. This work comprises a numerical study of the method and its experimental verification using a dataset measured at the W2 beamline of the storage ring DORIS III equipped with a Talbot-Lau interferometer. The numerical and experimental results demonstrate that the presented method can handle incomplete data. It will be of interest for a wide range of DPC-CT applications in medicine, biology, and nondestructive testing.

  4. Reconstruction of gyrotropic phase-space distributions from one-dimensional projections

    DEFF Research Database (Denmark)

    Egedal, J.; Bindslev, H.

    2004-01-01

    This paper describes mathematical tools applicable to the reconstruction of anisotropic velocity distributions through the unfolding of data coming from techniques like collective Thomson scattering or laser induced fluorescence, where one-dimensional projections of the velocity space along....... An example is given based on alpha particle distribution in the Joint European Torus tokamak [P. H. Rebut and B. E. Keen, Fusion Technol. 11, 13 (1987)]. (C) 2004 American Institute of Physics....

  5. Time-resolved computed tomography of the liver: retrospective, multi-phase image reconstruction derived from volumetric perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Michael A.; Kartalis, Nikolaos; Aspelin, Peter; Albiin, Nils; Brismar, Torkel B. [Karolinska University Hospital, Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm (Sweden); Leidner, Bertil; Svensson, Anders [Karolinska University Hospital, Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Stockholm (Sweden); Karolinska University Hospital Huddinge, Department of Radiology, Stockholm (Sweden)

    2014-01-15

    To assess feasibility and image quality (IQ) of a new post-processing algorithm for retrospective extraction of an optimised multi-phase CT (time-resolved CT) of the liver from volumetric perfusion imaging. Sixteen patients underwent clinically indicated perfusion CT using 4D spiral mode of dual-source 128-slice CT. Three image sets were reconstructed: motion-corrected and noise-reduced (MCNR) images derived from 4D raw data; maximum and average intensity projections (time MIP/AVG) of the arterial/portal/portal-venous phases and all phases (total MIP/ AVG) derived from retrospective fusion of dedicated MCNR split series. Two readers assessed the IQ, detection rate and evaluation time; one reader assessed image noise and lesion-to-liver contrast. Time-resolved CT was feasible in all patients. Each post-processing step yielded a significant reduction of image noise and evaluation time, maintaining lesion-to-liver contrast. Time MIPs/AVGs showed the highest overall IQ without relevant motion artefacts and best depiction of arterial and portal/portal-venous phases respectively. Time MIPs demonstrated a significantly higher detection rate for arterialised liver lesions than total MIPs/AVGs and the raw data series. Time-resolved CT allows data from volumetric perfusion imaging to be condensed into an optimised multi-phase liver CT, yielding a superior IQ and higher detection rate for arterialised liver lesions than the raw data series. (orig.)

  6. SIMULTANEOUS PIV/PTV MEASUREMENTS OF BUBBLE AND PARTICLE PHASES IN GAS-LIQUID TWO-PHASE FLOW BASED ON IMAGE SEPARATION AND RECONSTRUCTION

    Institute of Scientific and Technical Information of China (English)

    QU Jian-wu; MURAI Yuichi; YAMAMOTO Fujio

    2004-01-01

    A Particle Image Velocimetry (PIV) method based on the image separation and reconstruction with the median filter and triangular Bézier patch was proposed to measure multiple velocity fields from single-camera images in the present study. The method was examined on synthetic PIV images with the Green-Taylor two-phase vortex flows and the test results showed high accuracy and highly correct tracking percent compared with the exact solution. An experiment of the bubbly jet flow was also conducted as a practical demonstration of the present method. As a result, it is confirmed from the simulation image examination and the experimental measurement that the proposed method shows a good performance in the measurement of bubble and particle phases.

  7. Research on object-plane constraints and hologram expansion in phase retrieval algorithms for continuous-wave terahertz inline digital holography reconstruction.

    Science.gov (United States)

    Hu, Jiaqi; Li, Qi; Cui, Shanshan

    2014-10-20

    In terahertz inline digital holography, zero-order diffraction light and conjugate images can cause the reconstructed image to be blurred. In this paper, three phase retrieval algorithms are applied to conduct reconstruction based on the same near-field diffraction propagation conditions and image-plane constraints. The impact of different object-plane constraints on CW terahertz inline digital holographic reconstruction is studied. The results show that in the phase retrieval algorithm it is not suitable to impose restriction on the phase when the object is not isolated in the transmission-type CW terahertz inline digital holography. In addition, the effects of zero-padding expansion, boundary replication expansion, and apodization operation on reconstructed images are studied. The results indicate that the conjugate image can be eliminated, and a better reconstructed image can be obtained by adopting an appropriate phase retrieval algorithm after the normalized hologram extending to the minimum area, which meets the applicable range of the angular spectrum reconstruction algorithm by means of boundary replication.

  8. Three-Phase 3D Reconstruction of a LiCoO2 Cathode via FIB-SEM Tomography.

    Science.gov (United States)

    Liu, Zhao; Chen-Wiegart, Yu-Chen K; Wang, Jun; Barnett, Scott A; Faber, Katherine T

    2016-02-01

    Three-phase three-dimensional (3D) microstructural reconstructions of lithium-ion battery electrodes are critical input for 3D simulations of electrode lithiation/delithiation, which provide a detailed understanding of battery operation. In this report, 3D images of a LiCoO2 electrode are achieved using focused ion beam-scanning electron microscopy (FIB-SEM), with clear contrast among the three phases: LiCoO2 particles, carbonaceous phases (carbon and binder) and the electrolyte space. The good contrast was achieved by utilizing an improved FIB-SEM sample preparation method that combined infiltration of the electrolyte space with a low-viscosity silicone resin and triple ion-beam polishing. Morphological parameters quantified include phase volume fraction, surface area, feature size distribution, connectivity, and tortuosity. Electrolyte tortuosity was determined using two different geometric calculations that were in good agreement. The electrolyte tortuosity distribution versus position within the electrode was found to be highly inhomogeneous; this will lead to inhomogeneous electrode lithiation/delithiation at high C-rates that could potentially cause battery degradation.

  9. Fermi-surface reconstruction and complex phase equilibria in CaFe2As2.

    Science.gov (United States)

    Gofryk, K; Saparov, B; Durakiewicz, T; Chikina, A; Danzenbächer, S; Vyalikh, D V; Graf, M J; Sefat, A S

    2014-05-09

    Fermi-surface topology governs the relationship between magnetism and superconductivity in iron-based materials. Using low-temperature transport, angle-resolved photoemission, and x-ray diffraction, we show unambiguous evidence of large Fermi-surface reconstruction in CaFe2As2 at magnetic spin-density-wave and nonmagnetic collapsed-tetragonal (cT) transitions. For the cT transition, the change in the Fermi-surface topology has a different character with no contribution from the hole part of the Fermi surface. In addition, the results suggest that the pressure effect in CaFe2As2 is mainly leading to a rigid-band-like change of the valence electronic structure. We discuss these results and their implications for magnetism and superconductivity in this material.

  10. Musical Interfaces: Visualization and Reconstruction of Music with a Microfluidic Two-Phase Flow

    Science.gov (United States)

    Mak, Sze Yi; Li, Zida; Frere, Arnaud; Chan, Tat Chuen; Shum, Ho Cheung

    2014-10-01

    Detection of sound wave in fluids can hardly be realized because of the lack of approaches to visualize the very minute sound-induced fluid motion. In this paper, we demonstrate the first direct visualization of music in the form of ripples at a microfluidic aqueous-aqueous interface with an ultra-low interfacial tension. The interfaces respond to sound of different frequency and amplitude robustly with sufficiently precise time resolution for the recording of musical notes and even subsequent reconstruction with high fidelity. Our work shows the possibility of sensing and transmitting vibrations as tiny as those induced by sound. This robust control of the interfacial dynamics enables a platform for investigating the mechanical properties of microstructures and for studying frequency-dependent phenomena, for example, in biological systems.

  11. 3D optical phase reconstruction within PMMA samples using a spectral OCT system

    Science.gov (United States)

    Briones-R., Manuel d. J.; De La Torre-Ibarra, Manuel H.; Mendoza Santoyo, Fernando

    2015-08-01

    The optical coherence tomography (OCT) technique has proved to be a useful method in biomedical areas such as ophthalmology, dentistry, dermatology, among many others. In all these applications the main target is to reconstruct the internal structure of the samples from which the physician's expertise may recognize and diagnose the existence of a disease. Nowadays OCT has been applied one step further and is used to study the mechanics of some particular type of materials, where the resulting information involves more than just their internal structure and the measurement of parameters such as displacements, stress and strain. Here we report on a spectral OCT system used to image the internal 3D microstructure and displacement maps from a PMMA (Poly-methyl-methacrylate) sample, subjected to a deformation by a controlled three point bending and tilting. The internal mechanical response of the polymer is shown as consecutive 2D images.

  12. Fermi-Surface Reconstruction and Complex Phase Equilibria in CaFe2As2

    Science.gov (United States)

    Gofryk, K.; Saparov, B.; Durakiewicz, T.; Chikina, A.; Danzenbächer, S.; Vyalikh, D. V.; Graf, M. J.; Sefat, A. S.

    2014-05-01

    Fermi-surface topology governs the relationship between magnetism and superconductivity in iron-based materials. Using low-temperature transport, angle-resolved photoemission, and x-ray diffraction, we show unambiguous evidence of large Fermi-surface reconstruction in CaFe2As2 at magnetic spin-density-wave and nonmagnetic collapsed-tetragonal (cT) transitions. For the cT transition, the change in the Fermi-surface topology has a different character with no contribution from the hole part of the Fermi surface. In addition, the results suggest that the pressure effect in CaFe2As2 is mainly leading to a rigid-band-like change of the valence electronic structure. We discuss these results and their implications for magnetism and superconductivity in this material.

  13. El Niño phases embedded in Asian and North American drought reconstructions

    Science.gov (United States)

    Li, Jinbao; Xie, Shang-Ping; Cook, Edward R.

    2014-02-01

    The amplitude of El Niño-Southern Oscillation (ENSO) varies substantially at each phase of its evolution, affecting the timing and patterns of atmospheric teleconnections around the globe. Instrumental records are too short to capture the full behavior of ENSO variability. Here we use the well-validated Monsoon Asia Drought Atlas (MADA) and North America Drought Atlas (NADA) for the past 700 years, and show that tree-ring records from different regions represent tropical sea surface temperature (SST) conditions at various phases of ENSO. Three modes of tree-ring based summer drought variability are found to be correlated with ENSO: summer droughts over the Maritime Continent and Southwest North America (NA), and a dipole mode between Central and South Asia. A lagged correlation analysis is performed to determine the time when precipitation and temperature anomaly imprints on summer droughts as recorded in tree-rings. Drought anomalies in the Maritime Continent and Southwest NA represent ENSO at the developing and peak phases respectively, while those over Central/South Asia are associated with tropical-wide SST anomalies (including the Indian Ocean) at the decay phase of ENSO. Thus proxy records from different regions can provide valuable information on long-term behavior of ENSO at different phases.

  14. Availability of MCNP & MATLAB for reconstructing the water-vapor two-phase flow pattern in neutron radiography

    Institute of Scientific and Technical Information of China (English)

    FENG Qixi; FENG Quanke; TAKESHI Kawai

    2008-01-01

    The China Advanced Research Reactor (CARR) is scheduled to be operated in the autumn of 2008. In this paper, we report preparations for installing the neutron radiography instrument (NRI) and for utilizing it efficiently. The 2-D relative neutron intensity profiles for the water-vapor two-phase flow inside the tube were obtained using the MCNP code without influence of γ-ray and electronic-noise. The MCNP simulation of the 2-D neutron intensity profile for the water-vapor two-phase flow was demonstrated. The simulated 2-D neutron intensity profiles could be used as the benchmark data base by calibrating part of the data measured by the CARR-NRI. The 3-D objective images allow us to understand the flow pattern more clearly and it is reconstructed using the MATLAB through the threshold transformation techniques. And thus it is concluded that the MCNP code and the MATLAB are very useful for constructing the benchmark data base for the investigation of the water-vapor two-phase flow using the CARR-NRI.

  15. Fermi surface reconstruction and multiple quantum phase transitions in the antiferromagnet CeRhIn5.

    Science.gov (United States)

    Jiao, Lin; Chen, Ye; Kohama, Yoshimitsu; Graf, David; Bauer, E D; Singleton, John; Zhu, Jian-Xin; Weng, Zongfa; Pang, Guiming; Shang, Tian; Zhang, Jinglei; Lee, Han-Oh; Park, Tuson; Jaime, Marcelo; Thompson, J D; Steglich, Frank; Si, Qimiao; Yuan, H Q

    2015-01-20

    Conventional, thermally driven continuous phase transitions are described by universal critical behavior that is independent of the specific microscopic details of a material. However, many current studies focus on materials that exhibit quantum-driven continuous phase transitions (quantum critical points, or QCPs) at absolute zero temperature. The classification of such QCPs and the question of whether they show universal behavior remain open issues. Here we report measurements of heat capacity and de Haas-van Alphen (dHvA) oscillations at low temperatures across a field-induced antiferromagnetic QCP (Bc0 ≈ 50 T) in the heavy-fermion metal CeRhIn5. A sharp, magnetic-field-induced change in Fermi surface is detected both in the dHvA effect and Hall resistivity at B0* ≈ 30 T, well inside the antiferromagnetic phase. Comparisons with band-structure calculations and properties of isostructural CeCoIn5 suggest that the Fermi-surface change at B0* is associated with a localized-to-itinerant transition of the Ce-4f electrons in CeRhIn5. Taken in conjunction with pressure experiments, our results demonstrate that at least two distinct classes of QCP are observable in CeRhIn5, a significant step toward the derivation of a universal phase diagram for QCPs.

  16. GPU accelerated iterative SENSE reconstruction of radial phase encoded whole-heart MRI

    DEFF Research Database (Denmark)

    Sørensen, Thomas Sangild; Prieto, Claudia; Atkinson, David

    2010-01-01

    Isotropic whole-heart imaging has become an important protocol in simplifying cardiac MRI. The acquisition time can however be a prohibiting factor. To reduce acquisition times a 3D scheme combining Cartesian sampling in the readout direction with radial sampling in the phase encoding plane was r...

  17. Cytotoxicity of Cinnabar and Cinnabar-containing Compounds in Human Liver HL-7702 Cells%朱砂、含朱砂复方对人肝细胞的毒性对比研究

    Institute of Scientific and Technical Information of China (English)

    付中祥; 时京珍; 刘杰; 张永萍

    2013-01-01

    Objective:To study the toxicity of cinnabr,Zhusha Anshen Wan,Liaoyuan Hetang Huafeng Dan,Wansheng Huafeng Dan,HgS,HgC12 and MeHg in human liver HL-7702 cells.Method:Cultured cells were treated with cinnabar containing compounds and mercurial for 24 h,and was determined by the MTS assay,extracellular and intracellular Hg contents were determined by atomic fluoresence detector.Result:The cytotoxicity of cinnabr,Zhusha Anshen Wan,Liaoyuan Hetang Huafeng Dan,Wansheng Huafeng Dan,HgS had a obvious difference compared with HgCl2 and MeHg is same as the intracellular and extracellular mercury accumulation.Conclusion:The toxicity of cinnabr,Zhusha Anshen Wan,Liaoyuan Hetang Huafeng Dan,Wansheng Huafeng Dan,HgS with same mercury accumulation and same mercury dissolution is extremely lower than the corresponding HgCl2 and MeHg in human liver HL-7702 cells.%目的:对比研究朱砂、几种含朱砂复方与其他汞存在形式对HL-7702人肝细胞的毒性.方法:分别以朱砂、朱砂安神丸、廖元和堂化风丹、万胜化风丹、硫化汞、氯化汞、甲基汞加入已接种于96孔板的HL-7702人肝细胞后,检测各组的细胞存活率、检测各组细胞内、外的汞含量.结果:等汞含量和等汞浸出量的朱砂、朱砂安神丸、廖元和堂化风丹、万胜化风丹和硫化汞对HL-7702人肝细胞的存活率与正常组无明显差异,与等汞含量和等汞浸出量的氯化汞和甲基汞均有明显差异(P<0.05);分别以等汞含量、等汞浸出量的朱砂、朱砂安神丸、廖元和堂化风丹、万胜化风丹和硫化汞培养的HL-7702人肝细胞内、外汞含量均低于氯化汞、甲基汞(P<0.05).结论:等汞含量、等汞浸出量的朱砂、朱砂安神丸、廖元和堂化风丹和万胜化风丹对人肝HL-7702细胞的毒性远小于对应等汞含量、等汞浸出量的氯化汞、甲基汞.

  18. Reconstructing the insulin secretion rate by Bayesian deconvolution of phase-type densities

    DEFF Research Database (Denmark)

    Andersen, Kim Emil; Højbjerre, Malene

    2005-01-01

    of the insulin secretion rate (ISR) can be done by solving a highly ill-posed deconvolution problem. We represent the ISR, the C-peptide concentration and the convolution kernel as scaled phase-type densities and develop a Bayesian methodology for estimating such densities via Markov chain Monte Carlo techniques....... Hereby closed form evaluation of ISR is possible. We demonstrate the methodology on experimental data from healthy subjects and obtain results which are more realistic than recently reported conclusions based upon methods where the ISR is considered as piecewise constant....

  19. Performance enhancement of the single-phase series active filter by employing the load voltage waveform reconstruction and line current sampling delay reduction methods

    DEFF Research Database (Denmark)

    Senturk, O.S.; Hava, A.M.

    2011-01-01

    This paper proposes the waveform reconstruction method (WRM), which is utilized in the single-phase series active filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line...... current sampling delay reduction method, a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous-reference-frame-based methods. The analytical, simulation, and experimental studies of a 2.5 k......W single-phase SAF compensated system prove the theory....

  20. Technique for phase measurement and surface reconstruction by use of colored structured light.

    Science.gov (United States)

    Skydan, Oleksandr A; Lalor, Michael J; Burton, David R

    2002-10-10

    We present a new method for improving the measurement of three-dimensional (3-D) shapes by using color information of the measured scene as an additional parameter. The widest used algorithms for 3-D surface measurement by use of structured fringe patterns are phase stepping and Fourier fringe analysis. There are a number of problems and limitations inherent in these algorithms that include: that the phase maps produced are wrapped modulo 2pi, that in some cases the acquired fringe pattern does not fill the field of view, that there may be spatially isolated areas, and that there is often invalid and/or noisy data. The new method presented to our knowledge for the first time here uses multiple colored fringe patterns, which are projected at different angles onto the measured scene. These patterns are analyzed with a specially adapted multicolor version of the standard Fourier fringe analysis method. In this way a number of the standard difficulties outlined above are addressed.

  1. On the theory of the reconstruction of a weak phase-amplitude object from its images, especially in electron microscopy. I. Isoplanatic imaging

    NARCIS (Netherlands)

    Ferwerda, H.A.; Hoenders, B.J.

    1975-01-01

    In this paper we discuss the reconstruction of a weak phase-amplitude object from its intensity image. This problem occurs in electron microscopy where the weak object approximation holds for not too low accelerating voltages (E>~100 keV). Isoplanatic imaging is assumed. The illumination is supposed

  2. Cosmic flows and the expansion of the local Universe from non-linear phase-space reconstructions

    Science.gov (United States)

    Heß, Steffen; Kitaura, Francisco-Shu

    2016-03-01

    In this work, we investigate the impact of cosmic flows and density perturbations on Hubble constant H0 measurements using non-linear phase-space reconstructions of the Local Universe (LU). In particular, we rely on a set of 25 precise constrained N-body simulations based on Bayesian initial conditions reconstructions of the LU using the Two-Micron Redshift Survey galaxy sample within distances of about 90 h-1 Mpc. These have been randomly extended up to volumes enclosing distances of 360 h-1 Mpc with augmented Lagrangian perturbation theory (750 simulations in total), accounting in this way for gravitational mode coupling from larger scales, correcting for periodic boundary effects, and estimating systematics of missing attractors (σlarge = 134 s-1 km). We report on Local Group (LG) speed reconstructions, which for the first time are compatible with those derived from cosmic microwave background-dipole measurements: |vLG| = 685 ± 137 s-1 km. The direction (l, b) = (260.5° ± 13.3°, 39.1 ± 10.4°) is found to be compatible with the observations after considering the variance of large scales. Considering this effect of large scales, our local bulk flow estimations assuming a Λ cold dark matter model are compatible with the most recent estimates based on velocity data derived from the Tully-Fisher relation. We focus on low-redshift supernova measurements out to 0.01 tension. The first one is caused by the anisotropic distribution of supernovae, which aligns with the velocity dipole and hence induces a systematic boost in H0. The second one is due to the inhomogeneous matter fluctuations in the LU. In particular, a divergent region surrounding the Virgo Supercluster is responsible for an additional positive bias in H0. Taking these effects into account yields a correction of ΔH0 = -1.76 ± 0.21 s- 1 km Mpc- 1, thereby reducing the tension between local probes and more distant probes. Effectively H0 is lower by about 2 per cent.

  3. Experimental Study on the Use of Cinnabar During Pregnancy%朱砂妊娠用药的实验研究

    Institute of Scientific and Technical Information of China (English)

    陈斌; 肖敏; 李飞艳; 冯传平; 李辉; 刘杰

    2013-01-01

      目的:比较孕兔、幼兔、成年兔和新生兔(实验中孕兔所产)血汞含量,探讨不同兔对朱砂中汞的吸收情况。方法:用朱砂定时定量灌胃,用吹气富集-冷原子吸收法测定孕兔、幼兔、成年兔和新生兔血汞含量,并对实验数据进行统计学分析与比较。结果:血汞浓度:孕兔>幼兔>成年兔;新生兔血汞浓度显著高于孕兔给药前的血汞浓度。结论:实验表明朱砂中汞能透过孕兔胎盘屏障进入新生兔体内。鉴于汞的巨大毒性,提出《中国药典》在中药妊娠禁忌药中应增列朱砂。%Objectives: To investigate the absorption of the mercury in Cinnabarr by different rabbits, the blood mercury concentrations in pregnant rabbits, young rabbits, adult rabbits and newborn rabbits (the neonatal of the pregnant rabbits used in the experiment) were compared. Methods: The rabbits were given Cinnabar by intragastric administration quantitatively at regular intervals. The blood mercury concentrations in the pregnant rabbits, young rabbits, adult rabbits and newborn rabbits were measured by cold vapour atomic absorption spectrometry, and the experiment data has been analyzed. Results: Blood mercury concentrations were in the series as follows: pregnant rabbits > young rabbits > adult rabbits; The newborn rabbits had significantly higher blood mercury concentrations than that of adult rabbits. Conclusions: Experimental results indicated that the mercury in Cinnabar could through the placental barrier of pregnant rabbits to pass into the fetal rabbit. Considering the severe toxicity of mercury, Cinnabar should be added to the list of the contraindicated traditional Chinese medicines during pregnancy in Chinese Pharmacopoeia.

  4. Bioaccessibility as well as absorption and excretion of mercury in cinnabar%朱砂中汞的生物可接受性及其吸收与排泄

    Institute of Scientific and Technical Information of China (English)

    霍韬光; 王海宇; 林欣然; 畅蓓; 李维凯; 杨卉蕾; 张颖花; 姜泓

    2012-01-01

    研究了朱砂中汞的生物可接受性及其在体内的吸收与排泄.采用体外消化透析法测定了朱砂中汞的生物可按受性;计算了大鼠灌胃给予临床剂量(50 mg/kg)朱砂后汞的药动学参数;测定了给予临床剂量的朱砂后大鼠粪样中汞的排泄量.结果表明,朱砂中汞的溶出率为0.011%,生物可接受率为0.003 3%.大鼠灌胃给予临床剂量的朱砂后,汞的药动学参数为:最高血药浓度(Pmax)为(6.3±1.3)μg/L,达峰时间(tmax)为(1.3±0.4)h,半衰期(t1/2)为(4.2±0.5)h,血药浓度-时间曲线下面积(AUC)为(54.7±8.7) μg·h·L-1.给予朱砂12 h后汞在粪便中排泄量最大,96 h后在粪样中仍可检测到少量汞.朱砂中汞的生物可接受性较低,在体内吸收少,滞留时间较长,排泄缓慢,长期服用可在体内蓄积,产生毒性.%The bioaccessibility and absorption and excretion of mercury in cinnabar were studied. The bioaccessibility of mercury in cinnabar was evaluated by adopting in vitro digestion and dialysis method to simulate the conditions of gastric compartment and intestinal compartment of mercury. The pharmacokinetic parameters of mercury with respect to intragastric administration of cinnabar at a clinical dosage of 50 mg/kg for rats were calculated) and the excretion fraction of mercury in the fecal sample of the rats after intragastric administration of cinnabar at a clinical dosage was determined. Results indicate that, in the gastric compartment, the solubility of mercury from cinnabar is 0. 011%; and the bioaccessibility of mercury in the intestinal compartment is 0. 003 3%. The time-course pharmacokinetic parameters of mercury when the rats are intragastrically given cinnabar at a clinical dosage of 50 mg/kg are determined as the maximum concentration in blood Cmax(6.3 ± 1.3) μg/L, time to reach the maximum concentration tmax(l. 3 ± 0. 4) h, half-time period t1/2(4. 2 ± 0. 5) h, and area under the concentration-time curve AUC (54. 7

  5. Qualitative phase space reconstruction analysis of supply-chain inventor time series

    Directory of Open Access Journals (Sweden)

    Jinliang Wu

    2010-10-01

    Full Text Available The economy systems are usually too complex to be analysed, but some advanced methods have been developed in order to do so, such as system dynamics modelling, multi-agent modelling, complex adaptive system modelling and qualitative modelling. In this paper, we considered a supply-chain (SC system including several kinds of products. Using historic suppliers’ demand data, we firstly applied the phase space analysis method and then used qualitative analysis to improve the complex system’s performance. Quantitative methods can forecast the quantitative SC demands, but they cannot indicate the qualitative aspects of SC, so when we apply quantitative methods to a SC system we get only numerous data of demand. By contrast, qualitative methods can show the qualitative change and trend of the SC demand. We therefore used qualitative methods to improve the quantitative forecasting results. Comparing the quantitative only method and the combined method used in this paper, we found that the combined method is far more accurate. Not only is the inventory cost lower, but the forecasting accuracy is also better.

  6. A Two-Phase Space Resection Model for Accurate Topographic Reconstruction from Lunar Imagery with PushbroomScanners

    Directory of Open Access Journals (Sweden)

    Xuemiao Xu

    2016-04-01

    Full Text Available Exterior orientation parameters’ (EOP estimation using space resection plays an important role in topographic reconstruction for push broom scanners. However, existing models of space resection are highly sensitive to errors in data. Unfortunately, for lunar imagery, the altitude data at the ground control points (GCPs for space resection are error-prone. Thus, existing models fail to produce reliable EOPs. Motivated by a finding that for push broom scanners, angular rotations of EOPs can be estimated independent of the altitude data and only involving the geographic data at the GCPs, which are already provided, hence, we divide the modeling of space resection into two phases. Firstly, we estimate the angular rotations based on the reliable geographic data using our proposed mathematical model. Then, with the accurate angular rotations, the collinear equations for space resection are simplified into a linear problem, and the global optimal solution for the spatial position of EOPs can always be achieved. Moreover, a certainty term is integrated to penalize the unreliable altitude data for increasing the error tolerance. Experimental results evidence that our model can obtain more accurate EOPs and topographic maps not only for the simulated data, but also for the real data from Chang’E-1, compared to the existing space resection model.

  7. The Three-Dimensional Reconstruction of the AR 11158 During its Emergence Phase Using SDO/HMI Observations

    Science.gov (United States)

    Chintzoglou, Georgios; Zhang, J.

    2012-05-01

    A solar active region (AR) is a three dimensional magnetic structure formed in the convection zone, whose property is fundamentally important for determining coronal structure and solar activity when emerged. However, our knowledge on the detailed 3-D structure prior to its emergence is rather poor. Previous observational work on AR emergence has been limited by instrumental capabilities - low fidelity, low-cadence magnetograms. At the same time, our theoretical knowledge relies on overly simplified assumptions based on MHD simulations or the thin flux tube approximation. Here, we are able to observationally determine and reconstruct the three-dimensional magnetic structure of AR 11158 during the emergence phase and to characterize its magnetic connectivity and topology. This task is accomplished with the aid of the time-stacking method and advanced 3-D visualization, applied on magnetograph observations from the HMI instrument of the SDO mission, taking full advantage of its unprecedented temporal resolution. We find that the AR consists of two major dipoles. The two polarities of each dipole show interesting tree-like structure, i.e. while the bottom of the polarity appears as a single trunk-like flux tube, the top of the polarity has multiple branches, consisting of smaller and thinner flux tubes which connect to the branches of the opposite polarity. The four roots of the two dipoles align well along a straight line, while the top branches are slightly non-coplanar. The detailed 3-D topology and connectivity of AR 11158 will be presented in this meeting.

  8. WE-D-BRA-03: Four-Dimensional Dose Reconstruction Through Retrospective Phase Determination Using Cine Images of Electronic Portal Imaging Device

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J; Jung, J [East Carolina University, Greenville, NC (United States); Yi, B [Univ. of Maryland School Of Medicine, Baltimore, MD (United States); Kim, J [University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Yeo, I [Loma Linda Univ Medical Center, Loma Linda, CA (United States)

    2015-06-15

    Purpose: To test a method to reconstruct a four-dimensional (4D) dose distribution using the correlation of pre-calculated 4D electronic portal imaging device (EPID) images and measured cine-EPID images. Methods: 1. A phantom designed to simulate a tumor in lung (a polystyrene block with 3.0 cm diameter embedded in cork) was placed on a sinusoidally moving platform with 2 cm amplitude and 4 sec/cycle. Ten-phase 4D CT images were acquired for treatment planning and dose reconstruction. A 6MV photon beam was irradiated on the phantom with static (field size=5×8.5 cm{sup 2}) and dynamic fields (sliding windows, 10×10 cm{sup 2}, X1 MLC closing in parallel with the tumor movement). 2. 4D and 3D doses were calculated forwardly on PTV (1 cm margin). 3. Dose images on EPID under the fields were calculated for 10 phases. 4. Cine EPID images were acquired during irradiation. 5. Their acquisition times were correlated to the phases of the phantom at which irradiation occurred by inter-comparing calculated “reference” EPID images with measured images (2D gamma comparison). For the dynamic beam, the tumor was hidden under MLCs during a portion of irradiation time; the correlation performed when the tumor was visible was extrapolated. 6. Dose for each phase was reconstructed on the 4D CT images and summed over all phases. The summation was compared with forwardly calculated 4D and 3D dose distributions. Monte Carlo methods were used for all calculations. Results: For the open and dynamic beams, the 4D reconstructed doses showed the pass rates of 92.7 % and 100 %, respectively, at the isocenter plane given 3% / 3 mm criteria. The better agreement of the dynamic beam was from its dose gradient which blurred the otherwise sharp difference between forward and reconstructed doses. This also contributed slightly better agreement in DVH of PTV. Conclusion: The feasibility of 4D reconstruction was demonstrated.

  9. 朱砂对雄性大鼠精子质量影响的研究%Effect of cinnabar on sperm quality of male rats

    Institute of Scientific and Technical Information of China (English)

    顾祖曦; 刘炯; 谷颖敏; 姜昕; 吴文斌; 米金霞; 汤家铭

    2012-01-01

    Objective To observe the effect of cinnabar on the sperm motility and related movement parameters of male rats. Methods The male rats of reproductive toxicity section I were randomized into four groups; negative control group (0.5% CMC-Na) , small close cinnabar group (100 (xg/g) , medium dose group (300 μg/g) , large dose group (1 000 μg/g) and positive group (tripterygium glycosides 10 μg/g) , corresponding interventions were given in each group with the course of 6 weeks. After administration, the epididymis of each rat was taken to prepare sperm suspensions, then transfer 10 ui of rat sperm suspensions to sperm counting chambers to examine the quantity, vitality, motility of sperm by computer assisted sperm analysis ( CASA). Histo-pathological examination of testes and epididymis was done by HE staining. Results Compared with negative control group, the living rate, vitality, effective quantity and density of sperm in three cinnabar groups were decreases, with significant differences in living rate, vitality and density of sperm between negative control group and medium dose group, and with significant difference in effective quantity of sperm between negative control group and small dose group (P 0.05). Conclusion Cinnabar has negative effect on vitality, living rate, density and motility of rats sperm, and the results prompt that long term administration of cinnabar may had some harmful effect on male fertility.%目的 观察朱砂灌胃给药对雄性大鼠精子活力及相关运动参数的影响.方法 利用生殖毒性Ⅰ段雄性大鼠,按体质量随机分为阴性对照组(0.5% CMC-Na)、朱砂低剂量组(100μg∥g)、朱砂中剂量组(300 μg/g)、朱砂高剂量组(1 000ug/g)、阳性对照组(雷公藤多苷10 μg/g),分别给予相应的干预措施,共6周.给药结束后,取大鼠一侧附睾制备精子悬液,吸取10μl精子悬液至大鼠专用精子计数池,用计算机辅助精子分析系统(CASA)进行精子数量、活

  10. Phase-Space Reconstruction: a Path Towards the Next Generation of Nonlinear Differential Equation Based Models and Its Implications Towards Non-Uniform Sampling Theory

    Energy Technology Data Exchange (ETDEWEB)

    Charles R. Tolle; Mark Pengitore

    2009-08-01

    This paper explores the overlaps between the Control community’s work on System Identification (SysID) and the Physics, Mathematics, Chaos, and Complexity communities’ work on phase-space reconstruction via time-delay embedding. There are numerous overlaps between the goals of each community. Nevertheless, the Controls community can gain new insight as well as some new very powerful tools for SysID from the latest developments within the Physics, Mathematics, Chaos, and Complexity communities. These insights are gained via the work on phase-space reconstruction of non-linear dynamics. New methods for discovering non-linear differential based equations that evolved from embedding operations can shed new light on hybrid-systems theory, Nyquest-Shannon’s Theories, and network based control theory. This paper strives to guide the Controls community towards a closer inspection of the tools and additional insights being developed within the Physics, Mathematics, Chaos, and Complexity communities for discovery of system dynamics, the first step in control system development. The paper introduces the concepts of phase-space reconstruction via time-delay embedding (made famous byWhitney, Takens, and Sauer’s Thoreoms), intergrate-and-fire embedding, and non-linear differential equation discovery based on Perona’s method.

  11. Accuracy and precision of reconstruction of complex refractive index in near-field single-distance propagation-based phase-contrast tomography

    Science.gov (United States)

    Gureyev, Timur; Mohammadi, Sara; Nesterets, Yakov; Dullin, Christian; Tromba, Giuliana

    2013-10-01

    We investigate the quantitative accuracy and noise sensitivity of reconstruction of the 3D distribution of complex refractive index, n(r)=1-δ(r)+iβ(r), in samples containing materials with different refractive indices using propagation-based phase-contrast computed tomography (PB-CT). Our present study is limited to the case of parallel-beam geometry with monochromatic synchrotron radiation, but can be readily extended to cone-beam CT and partially coherent polychromatic X-rays at least in the case of weakly absorbing samples. We demonstrate that, except for regions near the interfaces between distinct materials, the distribution of imaginary part of the refractive index, β(r), can be accurately reconstructed from a single projection image per view angle using phase retrieval based on the so-called homogeneous version of the Transport of Intensity equation (TIE-Hom) in combination with conventional CT reconstruction. In contrast, the accuracy of reconstruction of δ(r) depends strongly on the choice of the "regularization" parameter in TIE-Hom. We demonstrate by means of an instructive example that for some multi-material samples, a direct application of the TIE-Hom method in PB-CT produces qualitatively incorrect results for δ(r), which can be rectified either by collecting additional projection images at each view angle, or by utilising suitable a priori information about the sample. As a separate observation, we also show that, in agreement with previous reports, it is possible to significantly improve signal-to-noise ratio by increasing the sample-to-detector distance in combination with TIE-Hom phase retrieval in PB-CT compared to conventional ("contact") CT, with the maximum achievable gain of the order of 0.3δ /β. This can lead to improved image quality and/or reduction of the X-ray dose delivered to patients in medical imaging.

  12. Noise-tolerance analysis for detection and reconstruction of absorbing inhomogeneities with diffuse optical tomography using single- and phase-correlated dual-source schemes

    Science.gov (United States)

    Kanmani, B.; Vasu, R. M.

    2007-03-01

    An iterative reconstruction procedure is used to invert intensity data from both single- and phase-correlated dual-source illuminations for absorption inhomogeneities. The Jacobian for the dual source is constructed by an algebraic addition of the Jacobians estimated for the two sources separately. By numerical simulations, it is shown that the dual-source scheme performs superior to the single-source system in regard to (i) noise tolerance in data and (ii) ability to reconstruct smaller and lower contrast objects. The quality of reconstructions from single-source data, as indicated by mean-square error at convergence, is markedly poorer compared to their dual-source counterpart, when noise in data was in excess of 2%. With fixed contrast and decreasing inhomogeneity diameter, our simulations showed that, for diameters below 7 mm, the dual-source scheme has a higher percentage contrast recovery compared to the single-source scheme. Similarly, the dual-source scheme reconstructs to a higher percentage contrast recovery from lower contrast inhomogeneity, in comparison to the single-source scheme.

  13. Reconstruction of electrical capacitance tomography images based on fast linearized alternating direction method of multipliers for two-phase flow system

    Institute of Scientific and Technical Information of China (English)

    Chongkun Xia; Chengli Su⁎; Jiangtao Cao; Ping Li

    2016-01-01

    Electrical capacitance tomography (ECT) has been applied to two-phase flow measurement in recent years. Image reconstruction algorithms play an important role in the successful applications of ECT. To solve the il-posed and nonlinear inverse problem of ECT image reconstruction, a new ECT image reconstruction method based on fast lin-earized alternating direction method of multipliers (FLADMM) is proposed in this paper. On the basis of theoretical analysis of compressed sensing (CS), the data acquisition of ECT is regarded as a linear measurement process of permittivity distribution signal of pipe section. A new measurement matrix is designed and L1 regularization method is used to convert ECT inverse problem to a convex relaxation problem which contains prior knowledge. A new fast alternating direction method of multipliers which contained linearized idea is employed to minimize the objective function. Simulation data and experimental results indicate that compared with other methods, the quality and speed of reconstructed images are markedly improved. Also, the dynamic experimental results in-dicate that the proposed algorithm can fulfil the real-time requirement of ECT systems in the application.

  14. Arsenic and Mercury Containing Traditional Chinese Medicine (Realgar and Cinnabar Strongly Inhibit Organic Anion Transporters, Oat1 and Oat3, In Vivo in Mice

    Directory of Open Access Journals (Sweden)

    Wen-Hao Yu

    2015-01-01

    Full Text Available Toxic heavy metals, including mercury (Hg and arsenic (As, accumulate preferentially in kidneys and always cause acute renal failure. The aim of this study was to investigate whether these samples affect organic anion transporters, Oat1 and Oat3, in vivo in mice kidney. Mice (n=10 were orally treated with investigational samples. After last administration, all mice were i.v. p-aminohippuric acid (PAH, and the blood and kidneys samples were collected. The concentrations of PAH were quantified by spectrophotometry. mRNA expressions of Oat1 and Oat3 were assayed by real-time PCR. In comparison with corresponding control, major pharmacokinetic parameters of PAH in sera were significantly changed by investigational samples (p<0.05, PAH accumulations in the kidney tissues were significantly higher (p<0.05, PAH uptake by renal slices was greatly reduced, Oat1 and Oat3 mRNA expression were significantly inhibited in investigational sample groups. Arsenic and mercury containing traditional Chinese medicine (Realgar and Cinnabar probably induce kidney damage through inhibiting several members of the organic anion transporters (such as OAT1 and OAT3.

  15. High-Performance Harmonic Isolation and Load Voltage Regulation of the Three-Phase Series Active Filter Utilizing the Waveform Reconstruction Method

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Hava, Ahmet M.

    2009-01-01

    . The SAF-compensated system utilizing WRM provides highperformance load harmonic voltage isolation and load voltage regulation at steady-state and during transients compared to the system utilizing the synchronous reference-frame-based signal decomposition. In addition, reducing the line current sampling......This paper develops a waveform reconstruction method (WRM) for high accuracy and bandwidth signal decomposition of voltage-harmonic-type three-phase diode rectifier load voltage into its harmonic and fundamental components, which are utilized in the series active filter (SAF) control algorithms...

  16. A Preliminary Study on the Reconstruction Algorithm of the Bubble Size to Inspect Two-phase Flows Using Single Cone-beam X-ray

    Energy Technology Data Exchange (ETDEWEB)

    Yim, Che Wook; Kim, Song Hyun; Shin, Chang Ho [Hanyang University, Seoul (Korea, Republic of)

    2015-05-15

    In two-phase flow, the motions of dispersed bubbles influence fluid properties such as heat transfer. In order to analyze how the bubble motion affects the fluid property, various techniques have been developed. An optical method has been used for the analysis of the single-phase flow such as Liquid Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV). However, it has some significant application problems which cannot be used for the opaque fluid and two phase flows. Phase-Doppler Method, another optical method, can be applied to the two-phase flow analysis. It is noted that the method also has difficulty to analyze the opaque flows. In a previous study, x-ray PIV method was proposed as the technique to measure the flow velocity and to get the flow vector field. However, there is no appropriate approach to analyze the bubble size for the two phase flows. In this study, a technique to estimate the bubble size by using x-ray is proposed as a preliminary study to develop an algorithm of the two phase flow analysis. In this study, a reconstruction algorithm of bubble size in two-phase flows using single x-ray was proposed. The analysis shows that 3-dimensional bubble size can be estimated by the multichannel detectors with the detection information. Also, a preliminary study on multi-bubble cases was performed. The analysis of the results show that that multiple bubbles can be separated by using the property that is the symmetry of bubbles. This proposed algorithm can detect the bubbles in flow of opaque fluids or nontransparent pipes which cannot be analyzed by optical methods. It is expected that the proposed method can utilized to inspect the bubbles in two-phase bubbly flow.

  17. 方位多相位中心SAR信号重建误差分析%Reconstruction error of azimuth multiple-phase-center

    Institute of Scientific and Technical Information of China (English)

    马喜乐; 董臻; 何峰; 孙造宇; 梁甸农

    2014-01-01

    就方位多相位中心(Azimuth Multiple-Phase-Center,AMPC)合成孔径雷达(Synthetic Aperture Radar,SAR)系统的阵列误差对信号重建性能的影响进行分析。将阵列误差建模为随机过程,结合最小二乘(Least-Square,LS)算法,推导了AMPC SAR误差功率谱的解析表达式,进而得到了AMPC SAR的信噪比与方位模糊比的解析表达式。仿真实验验证了理论分析的正确性。分析指出,随着系统脉冲重复频率的升高,有必要通过减小重建系数以实现重建性能的提升。分析方法与结果对AMPC SAR系统设计以及图像质量预估提供有效支撑。%Influence of array errors of azimuth multiple-phase-center (AMPC)synthetic aperture radar (SAR)on signal reconstruction performance is investigated.The array errors were modeled as stochastic process.In combination with least-square (LS)algorithm,the analytical expression of the reconstruction error power spectrum was derived.Then,the analytical expressions of signal to noise ratio (SNR)and azimuth ambiguity to signal ratio (AASR)were obtained.Experiment results confirm the validity of the theoretical analyses.Analytical results indicate that the image quality of AMPC SAR can be improved by decreasing the reconstruction coefficient when the pulse repetition frequency (PRF)increases. The approaches and results are helpful to the system design and the image quality evaluation of AMPC SAR.

  18. ACL reconstruction

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007208.htm ACL reconstruction To use the sharing features on this page, please enable JavaScript. ACL reconstruction is surgery to reconstruct the ligament in ...

  19. Mercury analysis of acid- and alkaline-reduced biological samples: identification of meta-cinnabar as the major biotransformed compound in algae.

    Science.gov (United States)

    Kelly, David; Budd, Kenneth; Lefebvre, Daniel D

    2006-01-01

    The biotransformation of Hg(II) in pH-controlled and aerated algal cultures was investigated. Previous researchers have observed losses in Hg detection in vitro with the addition of cysteine under acid reduction conditions in the presence of SnCl2. They proposed that this was the effect of Hg-thiol complexing. The present study found that cysteine-Hg, protein and nonprotein thiol chelates, and nucleoside chelates of Hg were all fully detectable under acid reduction conditions without previous digestion. Furthermore, organic (R-Hg) mercury compounds could not be detected under either the acid or alkaline reduction conditions, and only beta-HgS was detected under alkaline and not under acid SnCl2 reduction conditions. The blue-green alga Limnothrix planctonica biotransformed the bulk of Hg(II) applied as HgCl2 into a form with the analytical properties of beta-HgS. Similar results were obtained for the eukaryotic alga Selenastrum minutum. No evidence for the synthesis of organomercurials such as CH3Hg+ was obtained from analysis of either airstream or biomass samples under the aerobic conditions of the study. An analytical procedure that involved both acid and alkaline reduction was developed. It provides the first selective method for the determination of beta-HgS in biological samples. Under aerobic conditions, Hg(II) is biotransformed mainly into beta-HgS (meta-cinnabar), and this occurs in both prokaryotic and eukaryotic algae. This has important implications with respect to identification of mercury species and cycling in aquatic habitats.

  20. Optimisation of image reconstruction for phase-contrast x-ray Talbot-Lau imaging with regard to mechanical robustness

    Science.gov (United States)

    Seifert, M.; Kaeppler, S.; Hauke, C.; Horn, F.; Pelzer, G.; Rieger, J.; Michel, T.; Riess, C.; Anton, G.

    2016-09-01

    X-ray grating-based phase-contrast imaging opens new opportunities, inter alia, in medical imaging and non-destructive testing. Because, information about the attenuation properties and about the refractive properties of an object are gained simultaneously. Talbot-Lau imaging requires the knowledge of a reference or free-field image. The long-term stability of a Talbot-Lau interferometer is related to the time span of the validity of a measured reference image. It would be desirable to keep the validity of the reference image for a day or longer to improve feasibility of Talbot-Lau imaging. However, for example thermal and other long-term external influences result in drifting effects of the phase images. Therefore, phases are shifting over time and the reference image is not valid for long-term measurements. Thus, artifacts occur in differential phase-contrast images. We developed an algorithm to determine the differential phase-contrast image with the help of just one calibration image, which is valid for a long time-period. With the help of this algorithm, called phase-plane-fit method, it is possible to save measurement-time, as it is not necessary to take a reference image for each measurement. Additionally, transferring the interferometer technique from laboratory setups to conventional imaging systems the necessary rigidity of the system is difficult to achieve. Therefore, short-term effects like vibrations or distortions of the system lead to imperfections within the phase-stepping procedure. Consequently, artifacts occur in all three image modalities (differential phase-contrast image, attenuation image and dark-field image) of Talbot-Lau imaging. This is a problem with regard to the intended use of phase-contrast imaging for example in clinical routine or non-destructive testing. In this publication an algorithm of Vargas et al is applied and complemented to correct inaccurate phase-step positions with the help of a principal component analysis (PCA

  1. Optimisation of image reconstruction for phase-contrast x-ray Talbot-Lau imaging with regard to mechanical robustness.

    Science.gov (United States)

    Seifert, M; Kaeppler, S; Hauke, C; Horn, F; Pelzer, G; Rieger, J; Michel, T; Riess, C; Anton, G

    2016-09-01

    X-ray grating-based phase-contrast imaging opens new opportunities, inter alia, in medical imaging and non-destructive testing. Because, information about the attenuation properties and about the refractive properties of an object are gained simultaneously. Talbot-Lau imaging requires the knowledge of a reference or free-field image. The long-term stability of a Talbot-Lau interferometer is related to the time span of the validity of a measured reference image. It would be desirable to keep the validity of the reference image for a day or longer to improve feasibility of Talbot-Lau imaging. However, for example thermal and other long-term external influences result in drifting effects of the phase images. Therefore, phases are shifting over time and the reference image is not valid for long-term measurements. Thus, artifacts occur in differential phase-contrast images. We developed an algorithm to determine the differential phase-contrast image with the help of just one calibration image, which is valid for a long time-period. With the help of this algorithm, called phase-plane-fit method, it is possible to save measurement-time, as it is not necessary to take a reference image for each measurement. Additionally, transferring the interferometer technique from laboratory setups to conventional imaging systems the necessary rigidity of the system is difficult to achieve. Therefore, short-term effects like vibrations or distortions of the system lead to imperfections within the phase-stepping procedure. Consequently, artifacts occur in all three image modalities (differential phase-contrast image, attenuation image and dark-field image) of Talbot-Lau imaging. This is a problem with regard to the intended use of phase-contrast imaging for example in clinical routine or non-destructive testing. In this publication an algorithm of Vargas et al is applied and complemented to correct inaccurate phase-step positions with the help of a principal component analysis (PCA

  2. Porcine Cloned Embryos Reconstructed with the Cell Nuclei of Tetraploid M-phase Fibroblast Cells Can Restore Normal Diploidy at the Blastocyst Stage.

    Science.gov (United States)

    Zhao, Q; Qiu, Y G; Tian, J T; Wang, C S; An, T Z

    2016-11-17

    The cell cycle of donor cells as a major factor that affects cloning efficiency remains debatable. G2/M phase cells as a donor can successfully produce cloned animals, but a minimal amount is known regarding nuclear remodeling events. In this study, porcine fetal fibroblasts (PFFs) were carefully synchronized at G1 or M phase as donor cells. Most of the cloned embryos reconstructed from PFFs at G1 (G1-embryos) or M (M-embryos) phase formed a pronucleus-like nucleus (PN) within 6-h post fusion (hpf), but the M-embryos formed PN earlier than the G1-embryos did. Moreover, 77.4% of the M-embryos formed two PNs, whereas the G1-embryos formed a single PN. The rate of extrusion of polar body-like structures by the M-embryos was significantly lower than that extruded by the G1-embryos (26.3% vs. 37.1%, P M-embryos were octoploid before the first cleavage. Furthermore, 81.25% of the blastomeres of blastocysts developed from the M-embryos showed abnormal ploidy compared with those developed from the G1-embryos (22.55%). However, some of the blastomeres remained diploid in all the M-embryos tested. A portion of the blastomeres restored normal diploidy in some of the M-embryos at the blastocyst stage. This finding provides an explanation for M-embryos developing to term.

  3. High Performance Harmonic Isolation By Means of The Single-phase Series Active Filter Employing The Waveform Reconstruction Method

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Hava, Ahmet M.

    2009-01-01

    current sampling delay reduction method (SDRM), a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous reference frame based methods. The analytical, simulation, and experimental studies of a 2...

  4. [Amputation or reconstruction of IIIB and IIIC open tibial fracture. Decision criteria in the acute phase and late functional outcome].

    Science.gov (United States)

    Seekamp, A; Regel, G; Ruffert, S; Ziegler, M; Tscherne, H

    1998-05-01

    In IIIB and IIIC type open tibial fractures (according to Gustilo) the primary decision that has to be made regarding therapy is wether or not the limb can be salvaged. To standardize the criteria for amputation different salvage scores have been established in recent years. In this study the Hannover Fracture Scale (HFS), the Predictive Salvage Index (PSI), the Mangled Extremity Severity Score (MESS) and the NISSSA score were evaluated regarding their clinical relevance. When ROC Analysis was performed for all these scores in our patients the HFS revealed the highest sensitivity (0.91), but low specificity (0.71). The highest specificity was noted for the MESS (0.97), which in parallel showed the lowest sensitivity (0.59). In general it seems to be essential to make the right decision initially in order to avoid secondary amputation. All the scores mentioned here appear to be helpful in decision making. Salvaged limbs in IIIB and IIIC fractures presented a comparable good outcome, whereas salvaged IIIC injuries with a high score presented an outcome which was as bad as in secondary amputations. Secondary amputated patients required not only significant longer hospitalization but also resulted in poor outcome compared with the patients having received reconstruction or primary amputation.

  5. Influence of temperature on the controlled growth kinetics and superstructural phase formation of indium on a reconstructed Si (113) 3 × 2 surface

    Science.gov (United States)

    Krishna TC, Shibin; Deshmukh, Rahul; Singh Chauhan, Amit Kumar; Goswami, Lalit; Govind

    2014-03-01

    The kinetics of growth, thermal stability and superstructural phase formation of the indium atom on a reconstructed Si (113) 3 × 2 surface at room temperature (RT), as well as at high substrate temperature (HT), is discussed. It was observed that at a very low flux rate of 0.08 ML min-1, In-adsorption at RT follows the Frank-van der Merwe (FM) growth mode, while for HT (>200 °C), In-islands (the Volmer-Weber-growth mode) were formed. The residual thermal desorption (RTD) analysis revealed the anomalous behaviour of temperature-driven layering to the clustering rearrangement of In atoms on the Si (113) surface for RT- and 200 °C-grown systems. The RTD study also demonstrates the effect of temperature on growth kinetics as well as on the multilayer/monolayer desorption pathway. The calculated bilayer desorption energy was found to be different for RT- (T B, 0.48 eV) and HT- (T B, 1.57 eV) grown In/Si(113) systems, while the monolayer desorption energy (T M, 2.56 eV) was the same in both the cases. Various coverage-dependent superstructural phases, such as Si(113) 3 × 2 + 3 × 1, 3 × 1, 3 × 2 + 1 × 3 and 1 × 1, have been observed during the RT- and HT-growth of In on the Si (113) surface. A complete phase diagram of In/Si(113) is deduced which depicts the evolution of novel phases as a function of substrate temperature and coverage.

  6. Reconstruction Setting Out

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The earthquake-hit Yushu shifts its focus from rescuing survivors to post-quake reconstruction The first phase of earthquake relief, in which rescuing lives was the priority, finished 12 days after a 7.1-magnitude earthquake struck the Tibetan Autonomous Prefecture of Yushu in northwest China’s Qinghai Province on April 14, and reconstruction of the area is now ready to begin.

  7. First-principles study of structural and electronic properties of different phases of GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Arabi, H. [Faculty of Science, Department of Physics, University of Birjand, Birjand (Iran, Islamic Republic of)]. E-mail: harabi@birjand.ac.ir; Pourghazi, A. [Faculty of Science, Department of Physics, University of Isfahan, Isfahan (Iran, Islamic Republic of); Ahmadian, F. [Faculty of Science, Department of Physics, University of Birjand, Birjand (Iran, Islamic Republic of); Nourbakhsh, Z. [Faculty of Science, Department of Physics, University of Isfahan, Isfahan (Iran, Islamic Republic of)

    2006-03-01

    We present a theoretical investigation of structural and electronic properties of the four known structural phases of GaAs (zinc-blende, sc16, cinnabar and Cmcm). We used the full potential linearized augmented plane wave method, within local density approximation, and also within generalized gradient approximation for the exchange correlation potential. The lattice constants, bulk modulus and its pressure derivative are calculated for each of the four phases. The data obtained for the transition pressures between different phases are presented. Band structures and densities of states of the four phases are also given. The results are compared with previous calculations and with experimental results.

  8. Reconstruction Setting Out

    Institute of Scientific and Technical Information of China (English)

    YIN PUMIN

    2010-01-01

    @@ The first phase of earthquake relief,in which rescuing lives was the priority,finished 12 days after a 7.1-magnitude earthquake struck the Tibetan Autonomous Prefecture of Yushu in northwest China's Qinghai Province on April 14,and reconstruction of the area is now ready to begin.

  9. Penile reconstruction

    Institute of Scientific and Technical Information of China (English)

    Giulio Garaffa; Salvatore Sansalone; David J Ralph

    2013-01-01

    During the most recent years,a variety of new techniques of penile reconstruction have been described in the literature.This paper focuses on the most recent advances in male genital reconstruction after trauma,excision of benign and malignant disease,in gender reassignment surgery and aphallia with emphasis on surgical technique,cosmetic and functional outcome.

  10. Speech emotion recognition based on phase space reconstruction%相空间重构在语音情感识别中的研究

    Institute of Scientific and Technical Information of China (English)

    叶吉祥; 陈鑫

    2014-01-01

    为了更为全面地表征语音情感状态,弥补线性情感特征参数在刻画不同情感类型上的不足,将相空间重构理论引入语音情感识别中来,通过分析不同情感状态下的混沌特征,提取Kolmogorov熵和关联维作为新的情感特征参数,并结合传统语音特征使用支持向量机(SVM)进行语音情感识别。实验结果表明,通过引入混沌参数,与传统物理特征进行识别的方案相比,准确率有了一定的提高,为语音情感的识别提供了一个新的研究途径。%In order to express the sound emotion state totally, make up the inadequate of emotional conventional linear argu-ment at depicting different types of character sentiments, this paper takes the phase space reconstruction theory into the sound emotional identification, by analyzing chaotic features on the different sound emotional states, proposes correlation dimension and Kolmogorov entropy as emotional characteristic parameters, combines with traditional voice acoustic features and uses Support Vector Machine(SVM)for speech emotion recognition. The results show that recognition accuracy is improved through using chaotic characteristic parameters, providing a new research approach for speech emotion recognition.

  11. Ligament reconstruction.

    Science.gov (United States)

    Glickel, Steven Z; Gupta, Salil

    2006-05-01

    Volar ligament reconstruction is an effective technique for treating symptomatic laxity of the CMC joint of the thumb. The laxity may bea manifestation of generalized ligament laxity,post-traumatic, or metabolic (Ehler-Danlos). There construction reduces the shear forces on the joint that contribute to the development and persistence of inflammation. Although there have been only a few reports of the results of volar ligament reconstruction, the use of the procedure to treat Stage I and Stage II disease gives good to excellent results consistently. More advanced stages of disease are best treated by trapeziectomy, with or without ligament reconstruction.

  12. Climate Reconstructions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Paleoclimatology Program archives reconstructions of past climatic conditions derived from paleoclimate proxies, in addition to the Program's large holdings...

  13. Breast Reconstruction

    Science.gov (United States)

    ... senos Preguntas Para el Médico Datos Para la Vida Komen El cuidado de sus senos:Consejos útiles ... that can help . Federal law requires most insurance plans cover the cost of breast reconstruction. Learn more ...

  14. Nonlinear Reconstruction

    CERN Document Server

    Zhu, Hong-Ming; Pen, Ue-Li; Chen, Xuelei; Yu, Hao-Ran

    2016-01-01

    We present a direct approach to non-parametrically reconstruct the linear density field from an observed non-linear map. We solve for the unique displacement potential consistent with the non-linear density and positive definite coordinate transformation using a multigrid algorithm. We show that we recover the linear initial conditions up to $k\\sim 1\\ h/\\mathrm{Mpc}$ with minimal computational cost. This reconstruction approach generalizes the linear displacement theory to fully non-linear fields, potentially substantially expanding the BAO and RSD information content of dense large scale structure surveys, including for example SDSS main sample and 21cm intensity mapping.

  15. ACL reconstruction - discharge

    Science.gov (United States)

    Anterior cruciate ligament reconstruction - discharge; ACL reconstruction - discharge ... had surgery to reconstruct your anterior cruciate ligament (ACL). The surgeon drilled holes in the bones of ...

  16. Comparison and Research of Cinnabar, Zhusha Anshen Wan and HgS on Rat Absorption and Distribution%朱砂、朱砂安神丸及氯化汞在小鼠体内吸收、分布对比

    Institute of Scientific and Technical Information of China (English)

    付中祥; 杨虹; 陈秀芬; 刘杰; 时京珍

    2013-01-01

    目的:对比研究朱砂、朱砂安神丸及氯化汞在小鼠体内的吸收、分布规律.方法:昆明种小鼠180只,分为正常组、朱砂临床剂量组(0.2 g·kg-1,ig)、朱砂高剂量组(11.2 g·kg-1,ig)、朱砂安神丸组(2 g·kg-1,ig)、氯化汞组(0.07 g·kg-1,ig),每组小鼠在给药1,2,4,8,16,24 h后各取6只鼠的血、脑、肝、肾,原子荧光光度法检测汞含量.结果:朱砂临床剂量组和朱砂安神丸组体内最大血药浓度及各时间点血药浓度与氯化汞组相比具有明显差异(P<0.05);朱砂临床剂量组与朱砂安神丸组各时间点肝、肾组织中汞含量与氯化汞组有显著性差异(p< 0.05);朱砂临床剂量组和朱砂高剂量组在血液和组织中汞含量亦有显著性差异(P<0.05);朱砂高剂量组脑中汞含量最高.结论:临床剂量的朱砂、朱砂安神丸的汞吸收及各组织的汞含量均明显低于高剂量的朱砂和氯化汞.%Objective: To study the regulation of Cinnabar, Zhusha Anshen wan (ZSASW) and HgS on absorption and distribution in mice. Method: Oral gavage was given to Kunming mice with cinnabar (0. 2 g · kg-1), high dose of cinnabar (11.2 g·kg-1), ZSASW (2g·kg-1) , HgS (0.07 g·kg-1) or saline daily for 1, 2, 4, 8, 16, 24 hours, mercury accumulation in blood, liver, kidney and brain was determined by atomic fluoresence detector. Result: In comparison, the maximal serum concentration and serum concentration in each time of cinnabar clinical dose group and ZSASW group have obvious difference with the HgCl2 group. The mercury accumulation in liver and kidney in each time of clinical dose group and ZSASW group have obvious difference with the HgCl2 group. The mercury accumulation in blood and organs also had obvious difference between cinnabar clinical dose group and high dose group, and the high dose has the maximal accumulation in brain. Conclusion: Both cinnabar clinical dose group and ZSASW group have obvious difference with cinnabar high

  17. Breast Reconstruction Alternatives

    Science.gov (United States)

    ... Breast Reconstruction Surgery Breast Cancer Breast Reconstruction Surgery Breast Reconstruction Alternatives Some women who have had a ... chest. What if I choose not to get breast reconstruction? Some women decide not to have any ...

  18. Smooth Reconstruction

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Eighty percent of the reconstruction projects in Sichuan Province will be completed by the end of the year Despite ruins still seen everywhere in the earthquake-hit areas in Sichuan (Province, new buildings have been completed, and many people have moved into new houses. Through cameras of the media, the faces, once painful and melancholy after last year’s earthquake, now look confident and firm, gratifying people all over the

  19. Maxillary reconstruction

    Directory of Open Access Journals (Sweden)

    Brown James

    2007-12-01

    Full Text Available This article aims to discuss the various defects that occur with maxillectomy with a full review of the literature and discussion of the advantages and disadvantages of the various techniques described. Reconstruction of the maxilla can be relatively simple for the standard low maxillectomy that does not involve the orbital floor (Class 2. In this situation the structure of the face is less damaged and the there are multiple reconstructive options for the restoration of the maxilla and dental alveolus. If the maxillectomy includes the orbit (Class 4 then problems involving the eye (enopthalmos, orbital dystopia, ectropion and diplopia are avoided which simplifies the reconstruction. Most controversy is associated with the maxillectomy that involves the orbital floor and dental alveolus (Class 3. A case is made for the use of the iliac crest with internal oblique as an ideal option but there are other methods, which may provide a similar result. A multidisciplinary approach to these patients is emphasised which should include a prosthodontist with a special expertise for these defects.

  20. Reconstruction of harmonic signals based on bispectrum

    Institute of Scientific and Technical Information of China (English)

    FAN Yangyu; SUN Jincai; LI Pingan; XU Jiadong; SHANG Jiuhao

    2000-01-01

    A method for accurate reconstruction of the harmonic signals from bispectrum is presented. Based on the analysis of the measured harmonic signal, a sinusoid signal with 0phase, 1-amplitude and half of the fundamental frequency combines with the measured signal to form a combined signal, and then the bispectrum analysis is carried out to reconstruct the phase and the amplitude of the measured signal accurately. Without the zero-phase assumption of the fundamental component, using the new method eliminates the phase shifting between the calculated Fourier phase and the true Fourier phase in the existing signal retrieval methods based on bispectrum. The simulation results show the effectiveness of the new method.

  1. Reconstruction of the Radiation Emergency Medical System From the Acute to the Sub-acute Phases After the Fukushima Nuclear Power Plant Crisis.

    Science.gov (United States)

    Ojino, Mayo; Ishii, Masami

    2014-02-01

    The radiation emergency medical system in Japan ceased to function as a result of the accident at the Fukushima Daiichi Nuclear Power Plant, which has commonly become known as the "Fukushima Accident." In this paper, we review the reconstruction processes of the radiation emergency medical system in order of events and examine the ongoing challenges to overcoming deficiencies and reinforcing the system by reviewing relevant literature, including the official documents of the investigation committees of the National Diet of Japan, the Japanese government, and the Tokyo Electric Power Company, as well as technical papers written by the doctors involved in radiation emergency medical activities in Fukushima. Our review has revealed that the reconstruction was achieved in 6 stages from March 11 to July 1, 2011: (1) Re-establishment of an off-site center (March 13), (2) Re-establishment of a secondary radiation emergency hospital (March 14), (3) Reconstruction of the initial response system for radiation emergency care (April 2), (4) Reinforcement of the off-site center and stationing of disaster medical advisors at the off-site center (April 4), (5) Reinforcement of the medical care system and an increase in the number of hospitals for non-contaminated patients (From April 2 to June 23), and (6) Enhancement of the medical care system in the Fukushima Nuclear Power Plant and the construction of a new medical care system, involving both industrial medicine and emergency medicine (July 1). Medical resources such as voluntary efforts, academic societies, a local community medical system and university hospitals involved in medical care activities on 6 stages originally had not planned. In the future, radiation emergency medical systems should be evaluated with these 6 stages as a basis, in order to reinforce and enrich both the existing and backup systems so that minimal harm will come to nuclear power plant workers or evacuees and that they will receive proper care. This

  2. Afghanistan Reconstruction

    Institute of Scientific and Technical Information of China (English)

    Fu Xiaoqiang

    2006-01-01

    @@ The Karzai regime has made some progress over the past four years and a half in the post-war reconstruction.However, Taliban's destruction and drug economy are still having serious impacts on the security and stability of Afghanistan.Hence the settlement of the two problems has become a crux of affecting the country' s future.Moreover, the Karzai regime is yet to handle a series of hot potatoes in the fields of central government' s authority, military and police building-up and foreign relations as well.

  3. Catch-up validation study of an in vitro skin irritation test method based on an open source reconstructed epidermis (phase II).

    Science.gov (United States)

    Groeber, F; Schober, L; Schmid, F F; Traube, A; Kolbus-Hernandez, S; Daton, K; Hoffmann, S; Petersohn, D; Schäfer-Korting, M; Walles, H; Mewes, K R

    2016-10-01

    To replace the Draize skin irritation assay (OECD guideline 404) several test methods based on reconstructed human epidermis (RHE) have been developed and were adopted in the OECD test guideline 439. However, all validated test methods in the guideline are linked to RHE provided by only three companies. Thus, the availability of these test models is dependent on the commercial interest of the producer. To overcome this limitation and thus to increase the accessibility of in vitro skin irritation testing, an open source reconstructed epidermis (OS-REp) was introduced. To demonstrate the capacity of the OS-REp in regulatory risk assessment, a catch-up validation study was performed. The participating laboratories used in-house generated OS-REp to assess the set of 20 reference substances according to the performance standards amending the OECD test guideline 439. Testing was performed under blinded conditions. The within-laboratory reproducibility of 87% and the inter-laboratory reproducibility of 85% prove a high reliability of irritancy testing using the OS-REp protocol. In addition, the prediction capacity was with an accuracy of 80% comparable to previous published RHE based test protocols. Taken together the results indicate that the OS-REp test method can be used as a standalone alternative skin irritation test replacing the OECD test guideline 404.

  4. Short-term wind power prediction based on Logistic mapping neural network of phase space reconstruction%基于Logistic映射相空间重构神经网络短期风电预测

    Institute of Scientific and Technical Information of China (English)

    韩亚军; 李太福; 杨小强

    2015-01-01

    Wind power is random ,intermittent and volatile ,it is difficult to accurately predict ,for the wind speed has a strong chaotic characteristic . It can use a short‐term prediction of phase space reconstruction theory methods to determine the optimal time delay and embedding dimension wind speed ,and then reconstruct the sample space ,and also use BP neural network to predict short‐term wind speed .The experimental results show that the model can get higher short‐term power generation forecasting accuracy .%针对风速有很强的混沌特性,采用一种相空间重构理论短期预测方法,确定风速的最佳延迟时间和嵌入维数,然后对样本空间进行重构,使用BP神经网络进行短期风速预测。实验结果表明,该模型可以较高的得到短期发电功率预测精度。

  5. 沈阳浑北灌区节水配套改造工程二期项目施工总结%Shenyang Hunbei irrigation water saving Reconstruct Project Phase II construction

    Institute of Scientific and Technical Information of China (English)

    董浩

    2015-01-01

    This paper focuses on Shenyang Hunbei irrigation water saving Reconstruct Project Phase II ,from foundation excavation,masonry mortar rubble masonry retaining wall construction,embankment foundation treatment and reclamation,geomembrane laying,pressure beam,concrete slope,retaining five feet,the con-struction methods,processes and key issues requiring attention are analyzed and discussed.%本文围绕沈阳浑北灌区节水配套改造工程二期项目,从基础开挖、浆砌石挡土墙砌筑施工、堤防基础处理与填筑、土工膜铺设、压梁、混凝土护坡、护脚五个方面,对施工方法、工艺及需要注意的重点问题进行了分析和讨论。

  6. Short-term Wind Speed Forecasting Based on Phase-space Reconstruction and Evolutionary Gaussian Process Model%基于相空间重构和进化高斯过程的短期风速预测

    Institute of Scientific and Technical Information of China (English)

    常纯; 李德胜

    2016-01-01

    A short-term wind speed forecasting method based on phase-space reconstruction and evolutionary Gaussian process model is proposed in this paper .Firstly, the autocorrelation method and false nearest neighbor method are applied to calculate the delay time and embedding dimension of the wind speed time series , which are used to accomplish the phase-space reconstruction of the chaotic wind speed time series .Secondly, the evolutionary Gaussian process model , which combines Gaussian process with evolutionary algorithm , is used to forcast the wind speed .This model uses Gaussian process model to determine the relationship between the input and output variables , and the improved PSO algorithm to optimize the hyper parameters .The prediction results show that the proposed method can improve the prediction accuracy .%提出一种基于相空间重构和进化高斯过程的短期风速预测方法。首先,运用自相关法和假近邻法分别得出原始风速时间序列的延迟时间和嵌入维数,实现混沌风速时间序列的相空间重构;然后,运用进化高斯过程回归模型进行建模,通过高斯过程模型确定输入量和输出量之间的关系,并用改进粒子群算法求取最优超参数。根据某实测风速数据进行了风速预测,结果表明本文所提出的方法能有效提高风速预测精度。

  7. Study on phase current reconstruction of inverter compressor based on single-resistor sampling%基于单电阻的变频压缩机相电流重构方法

    Institute of Scientific and Technical Information of China (English)

    李岳; 徐鸣; 黄跃进; 顾江萍; 沈希

    2013-01-01

    为了提高直流变频压缩机的控制效率,降低运行成本,需要对其电动机的定子相电流的精确采样.针对电机三相相电流与直流母线电流及逆变器开关状态的关系,结合压缩机电机的数学模型,采用了一种基于单电阻采样母线电流的电机相电流重构方法.首先,结合永磁同步电机(PMSM)的数学模型,对单电阻电流采样重构三相电流技术及其难点进行了原理上的分析;然后,在空间矢量PWM调制过程中的中、高频调制区的非观测区域采用了预测状态观测器的数学方法,正确、有效地完成了三相电流的重构;最后,基于STM32芯片设计了一套无传感器直流变频压缩机控制的平台.实验结果表明,该方法能够实现正确重构相电流,在低成本的变频冰箱领域具有很高的实际应用价值.%In order to improve the control efficiency of the DC inverter compressor and reduce cost, the phase current of motor stator should be sampled. Aiming at the relationship between the motor three-phase current, DC bus current and inverter switch states, three-phase current reconstruction using only a single-resistor in the inverter DC link was proposed. Firstly, based on the mathematical model of permanent magnet synchronous motor (PMSM) , the key technology and difficulties in reconstructing three-phase current by single-resistor sensor were analyzed. Then, a mathematical method of using predictive state observer to the non-observable regions of the middle and high frequency modulation region in the process of space vector PWM modulated was adopted. The three-phase current was constructed effectively and accurately. Finally,based on STM32 chip,a system of senseless DC inverter compressor control was designed. The hardware circuit of the single-resistor sensor was given. The results indicate that this method can correctly reconstruct the phase current and has a high practical value in the field of low-cost frequency

  8. Reconstructive Urology

    Directory of Open Access Journals (Sweden)

    Fikret Fatih Önol

    2014-11-01

    Full Text Available In the treatment of urethral stricture, Buccal Mucosa Graft (BMG and reconstruction is applied with different patch techniques. Recently often prefered, this approach is, in bulber urethra strictures of BMG’s; by “ventral onley”, in pendulous urethra because of thinner spingiosis body, which provides support and nutrition of graft; by means of “dorsal inley” being anastomosis. In the research that Cordon et al. did, they compared conventional BMJ “onley” urethroplast and “pseudo-spongioplasty” which base on periurethral vascular tissues to be nourished by closing onto graft. In repairment of front urethras that spongiosis supportive tissue is insufficient, this method is defined as peripheral dartos [çevre dartos?] and buck’s fascia being mobilized and being combined on BMG patch. Between the years 2007 and 2012, assessment of 56 patients with conventional “ventral onley” BMG urethroplast and 46 patients with “pseudo-spongioplasty” were reported to have similar success rates (80% to 84% in 3.5 year follow-up on average. While 74% of the patients that were applied pseudo-spongioplasty had disease present at distal urethra (pendulous, bulbopendulous, 82% of the patients which were applied conventional onley urethroplast had stricture at proximal (bulber urethra yet. Also lenght of the stricture at the pseudo-spongioplasty group was longer in a statistically significant way (5.8 cm to 4.7 cm on average, p=0.028. This study which Cordon et al. did, shows that conditions in which conventional sponjiyoplasti is not possible, periurethral vascular tissues are adequate to nourish BMG. Even it is an important technique in terms of bringing a new point of view to today’s practice, data especially about complications that may show up after pseudo-spongioplasty usage on long distal strictures (e.g. appearance of urethral diverticulum is not reported. Along with this we think that, providing an oppurtinity to patch directly

  9. Catch-up validation study of an in vitro skin irritation test method based on an open source reconstructed epidermis (phase I).

    Science.gov (United States)

    Mewes, K R; Fischer, A; Zöller, N N; Laubach, V; Bernd, A; Jacobs, A; van Rompay, A; Liebsch, M; Pirow, R; Petersohn, D

    2016-10-01

    We have developed a new in vitro skin irritation test based on an open source reconstructed epidermis (OS-REp) with openly accessible protocols for tissue production and test performance. Due to structural, mechanistic and procedural similarity, a blinded catch-up validation study for skin irritation according to OECD Performance Standards (PS) was conducted in three laboratories to promote regulatory acceptance, with OS-REp models produced at a single production site only. While overall sensitivity and predictive capacity met the PS requirements, overall specificity was only 57%. A thorough analysis of the test results led to the assumption that some of the false-positive classifications could have been evoked by volatile skin-irritating chemicals tested in the same culture plate as the non-irritants falsely predicted as irritants. With GC/MS and biological approaches the cross-contamination effect was confirmed and the experimental set-up adapted accordingly. Retesting of the affected chemicals with the improved experimental set-up and otherwise identical protocol resulted in correct classifications as non-irritants. Taking these re-test results into account, 93% overall sensitivity, 70% specificity and 82% accuracy was achieved, which is in accordance with the OECD PS. A sufficient reliability of the method was indicated by a within-laboratory-reproducibility of 85-95% and a between-laboratory-reproducibility of 90%.

  10. Transformer excitation inrush current recognition based on the phase space reconstruction%基于相空间重构的变压器励磁涌流识别

    Institute of Scientific and Technical Information of China (English)

    宋晓; 李平; 徐公林

    2012-01-01

    For the problem that transformer excitation inrush current can cause differential protection maloperation, based on the phase space reconstruction theory, phase spaces of transformer excitation inrush current and different internal fault current series are reconstructed from one-dimensional time series to high-dimensional phase space. Through the research of high dimensional phase space attractor's distribution and movement characteristics, dynamic characteristics are obtained form the original time series. And the characteristic of attractor, namely the correlation dimension is calculated to differentiate transformer excitation inrush current from internal fault current. Experimental analysis results indicate that the value of correlation dimension corresponding with current series of excitation inrush current is greater than 2, but the value of correlation dimension corresponding with current series of internal fault is between 1 and 2. Therefore, they are obviously different. So correlation dimension can serve as a kind of new features criterion to identify transformer excitation inrush current%针对变压器励磁涌流会引起差动保护误动的问题,应用相空间重构理论,对变压器励磁涌流和不同内部故障时的电流序列进行相空间重构,将一维的时间序列重构到高维相空间,通过研究高维相空间吸引子的分布规律和运动特点,获取原始时间序列的动力学特性.计算吸引子的特征量——关联维数来区分变压器励磁涌流与内部故障电流.实验分析结果表明:励磁涌流时电流序列对应的关联维数大于2,而内部故障时电流序列对应的关联维数在1和2之间,两者明显不同.因此关联维数可以作为一种新的特征判据来识别变压器励磁涌流.

  11. 多参考光合成孔径DMIPH术的细胞相位重构%Reconstruction of cell phase by multi-reference light synthetic aperture digital microsopic image plane holographic technology

    Institute of Scientific and Technical Information of China (English)

    巩文迪; 卢兆林; 刘佳毅

    2012-01-01

    Digital holographic microscopy (DHM) extracts the phase information directly instead of traditional optical microscopy, and records high frequency and low frequency information of an object more accurately. Based on DHM, cell phase was reconstructed by means of angular spectrum algorithm and least-squares unwrapping algorithm. Quantitative observation and effective measurement were earned out for living biological sample cells. The experiment results indicates that multi-reference light synthetic aperture digital microscopic image plane holography can be effectively applied to the amplitude and phase reconstruction of the microstructures of three-dimension objects, it can improve synthetic degree of system significantly in recording the object' s high frequency and low frequency information, and the diffraction limit resolution 12. 81p/mm can be obtained. The results show that super resolution imaging of digital holographic can be effectively implemented based on this system, and three-dimension topography information and accurate phase distribution of the microstructure cells can be obtained.%为了克服传统光学显微术无法直接提取相位信息的不足而能更准确记录物体高频和低频信息的合成,采用多参考光合成孔径数字显微像面全息系统,并结合角谱算法和最小二乘解包裹算法实现了细胞的相位重构.选取活体细胞组织等相位型生物进行作为实验样本,对其进行定量观察和有效测量.结果表明,多参考光合成孔径数字显微像面全息系统可以有效地应用于3维物体显微结构的振幅和相位重构,能显著地提高记录系统的高频和低频信息在全息图上的合成度,并实现超出系统的衍射极限12.81p/mm的分辨率.该系统可以有效地实现数字全息系统的超分辨率成像,从而获得细胞显微结构的3维形貌信息和准确的相位分布.

  12. The role of clinical pharmacists in the diagnosis and treatment of mercury poisoning caused by the topical use of cinnabar%临床药师在朱砂外用致汞中毒诊治中的作用

    Institute of Scientific and Technical Information of China (English)

    于丽; 轩姣; 李晋宝

    2016-01-01

    Objective:To explore the role of clinical pharmacists in the diagnosis and treatment of drug poisoning. Methods:According to the symptoms and medication history of the patient with mercury poisoning caused by topical use of cinnabar, clinical pharmacists provided some vermilion composition information for physicians and the basis for early diagnosis, and recommended to check the urinary mercury concentration and participated in the design of the treatment plan and carry out medication supervision after the clear diagnosis. Results:The concentration of acute urinary mercury in the patient exceeded the standard, however, it decreased to the normal level after the treatment of eliminating mercury and protecting liver and the condition was significantly improved. Conclusion: Clinical pharmacists can provide drug information for physicians in the treatment of drug poisoning, participate in making drug treatment plan and carry out pharmaceutical care.%目的:探讨临床药师在药物致中毒诊治中的作用。方法:在外用朱砂致汞中毒患者救治中,临床药师结合患者症状和用药史,为医师提供朱砂成分信息,并提出检查尿汞浓度的建议,为及早诊断提供依据,诊断明确后参与治疗方案的设计并开展用药监护。结果:急查患者尿汞浓度超标,经驱汞、保肝等治疗后,尿汞浓度降至正常,病情明显好转。结论:临床药师能够在药物中毒救治中提供药品信息、参与制定药物治疗方案和开展药学监护。

  13. Phase response reconstruction of arbitrary frequency grid for equivalent sampling oscilloscope based on NTN calibration%基于NTN校准的等效采样示波器任意频率栅相位响应重构

    Institute of Scientific and Technical Information of China (English)

    徐清华; 林茂六; 张亦弛

    2011-01-01

    研究提出了一种通过测量等效采样示波器幅度响应来获得其相位响应的算法.此方法是基于Kramers-Kronig关系式并配以基于NTN校准的相位响应测量实现的.实例证明:虽然Kramers-Kronig变换计算时的截断造成了相位估计上非常大的误差,但是此误差可以通过少量的正交基函数拟合出来.作为一个实例,本文利用NTN校准和扫频法校准的结果获得了等效采样示波器的复频率响应,在1 MHz~50 GHz频率范围内,其频率分辨率达到了1 MHz.重构出的相位响应标准不确定度小于0.6°.结果表明:此方法可以重构出等效采样示波器任意频率栅复频率响应.%Describes an algorithm for determining the minimum phase response of equivalent sampling oscilloscopes.The procedure is based on Kramers-Kronig relation in combination with the harmonic phase response measurement of NTN calibration. Although the truncation of Kramers-Kronig transform gives rise to large errors in estimated phase,these errors can be fitted using three basis functions. As an example, we got the phase response reconstruction of sampling oscilloscope in frequency domain; its frequency resolution achieves 1MHz in the frequency range from 1 MHz ~ 50 GHz, and the phase uncertainty of the phase response is less than 0.6°. These results are based on the data obtained using an NTN technique in combination with swept-sine calibration procedure. The above results show that the algorithm can be used to obtain fine phase response of equivalent sampling oscilloscopes.

  14. 朱砂灌胃给药后汞在孕大鼠脏器内的分布和排泄途径研究%Study on Distribution in Organs and Excretion Pathway of Mercury in Pregnant Rats after Administration of Cinnabar

    Institute of Scientific and Technical Information of China (English)

    汤家铭; 米金霞; 吴文斌; 谷颖敏; 李咏梅; 夏晶; 张甦; 曹帅; 季申

    2011-01-01

    Objective: To study the distribution and excretion pathway of mercury in pregnant rats after administration of cinnabar. Methods; Compared with the reproductive toxicity test, the female SD rats after mating were randomly divided into high (1 000 mg/kg) , medium (300 mg/kg) , and low-dose (100 mg/kg) cinnabar groups, and negative control group (0.5% CMC-Na) , with ten rats in each group. The rats in different dose cinnabar groups were administered intragastrically with cinnabar from the sixth day to the fifteenth day after pregnancy, and all the rats were sacrificed on the twentieth day of pregnancy. The main organs (including heart, liver, spleen, lung, kidney, brain and uterus) , blood, placentae, fetuses and urine of the pregnant rats were obtained to detect the mercury concentration by inductively coupled plasma mass spectrometry ( ICP-MS) ; the feces were taken at different time points to determine the mercury concentration by inductively coupled plasma optical emission spectrometer (ICP-OES) ; the distribution in different organs and the excretion pathway of mercury were analyzed. Results: The mercury concentrations of the heart, liver, kidney and uterus of the rats in different dose cinnabar groups were higher than those of the rats in negative control group, and the concentration increased with the enhanced dose; there was no statistical difference on the mercury concentrations of the brain, placentae and fetuses between different dose cinnabar groups and negative control group. There were large amount of mercury in the feces on the second day after administration, and the mercury excretion accounted for 38. 2% ~ 50.4% of HgS intake; while the mercury excretion accounted for72.2% -86.6% on the tenth day after administration; The a-mount of HgS discharged in the feces decreased rapidly on the fourth day after drug discontinuation. Only extreme trace of mercury excreted from urine with dose-dependent pattern, and the mercury excretion maintained the high

  15. Dissolution, absorption and bioaccumulation in gastrointestinal tract of mercury in HgS-containing traditional medicines Cinnabar and Zuotai%含HgS传统药物朱砂和佐太中汞的胃肠道溶出及吸收蓄积研究

    Institute of Scientific and Technical Information of China (English)

    郑植元; 李岑; 张明; 杨红霞; 耿卢婧; 李林帅; 杜玉枝; 魏立新

    2015-01-01

    中药朱砂和藏药佐太的主要成分分别为α-HgS和β-HgS,但是关于朱砂、佐太、α-HgS和β-HgS中的汞在人体胃肠道中的溶出吸收以及在器官中的分布蓄积的比较研究未见报道.该研究模拟了4种硫化汞类化合物在人体胃肠道中的溶出过程,然后测定汞溶出度,分别比较不同药物间汞溶出度差异以及不同溶液的促溶能力差异.为了探究朱砂和佐太在机体内的吸收蓄积情况,分别以其临床等效剂量灌胃小鼠,同时设置与朱砂等汞量的α-HgS和β-HgS给药组,以及与佐太等汞量的β-HgS和HgC12给药组,然后比较各组不同药物中的汞在小鼠体内吸收蓄积能力差异以及小鼠不同组织器官对汞的蓄积能力差异.实验结果表明,佐太在人工胃肠液中的汞溶出度均较大,其次是β-HgS,朱砂和α-HgS也有一定的溶出.对于小鼠汞吸收蓄积实验,HgCl2吸收蓄积能力最强,β-HgS其次,α-HgS略强于朱砂;不同器官对汞的蓄积能力大小依次是肾>肝>脑.该研究贴近临床实际,观察含汞药物朱砂和佐太在胃肠道中的溶出以及吸收分布蓄积,为临床安全用药提供参考,也希望为含重金属药物的安全性评价提供研究模式.%α-HgS is the main component of traditional Chinese medicine cinnabar,while β-HgS is the main component of Tibetan medicine Zuotai.However,there was no comparative study on the dissolution and absorption in gastrointestinal tract and bioaccumulation in organs of mercury in Cinnabar,Zuotai,α-HgS and β-HgS.In this study,the dissolution process of the four compounds in the human gastrointestinal tract was simulated to determine the mercury dissolutions and compare the mercury dissolution of different medicines and the dissolution-promoting capacity of different solutions.To explore the absorption and bioaccumulation of cinnabar and Zuotai in organisms,mice were orally administered with clinical equivalent doses cinnabar and Zuotai

  16. A Short-term Wind Speed Prediction Model Using Phase-space Reconstructed Extreme Learning Machine%相空间重构的极端学习机短期风速预测模型

    Institute of Scientific and Technical Information of China (English)

    武峰雨; 乐秀瑶; 南东亮

    2013-01-01

    A quick and accurate prediction of wind speed can effectively reduce or avoid the adverse effects of wind farms on power system, and can as well improve the competitiveness of the wind farm in the electricity market. In this paper, according to the chaotic characteristics of the wind speed, a short-term wind speed prediction model using phase-space reconstructed extreme learning machine (ELM) is put forward. The decision of the delay time and embedding dimension is used to reconstruct the sample space, which makes the new sample better reflect the change characteristics of wind speed. On this basis, the ELM is applied for short-term wind speed prediction. Compared with the traditional prediction model, this method has the advantages of fast learning speed and good generalization performance. Therefore, a new method is provided for wind speed prediction.%对风速进行快速、准确的预测,可以有效地减小或避免风电场对电力系统的不利影响,同时提高风电场在电力市场中的竞争能力.根据风速具有混沌特性,提出一种相空间重构的极端学习机(extreme learningmachine,ELM)的短期风速预测模型,通过确定延迟时间和嵌入维数,对样本空间进行重构,使新的样本更能反映风速变化特性,在此基础上运用ELM进行短期风速预测.与传统的预测模型相比,该方法具有学习速度快、泛化性能好等优点,为风速预测提供了新方法.

  17. 基于相空间重构的神经网络短期风速预测%Short-Term Wind Speed Forecasting of Neural Network Based on Phase Space Reconstruction

    Institute of Scientific and Technical Information of China (English)

    廖志强; 李太福; 余德均; 程杨; 姚立忠

    2012-01-01

    针对风速具有较强的混沌特性,预测难度较大,提出了一种基于相空间重构的神经网络短期风速预测方法:对数据进行小波降噪,运用互信息法和虚假最近邻点法确定最佳的延迟时间和嵌入维数,对样本空间进行重构,使新的样本能够表征原始时间序列动态特性,更能反映风速变化特性.在此基础上运用BP神经网络进行短期风速预测.实验结果表明短期风速预测精度得到提高.%Considering the wind speed built-in a strong chaos characteristic and difficult to forecast, a short-term wind speed prediction method based on phase space reconstruction and neural network is proposed to predict wind speed data of time series. The data noises are reduced by wavelet de-noising. Optimal delay time is obtained by mutual information method and embedding dimension is also calculated by false nearest neighbor (FNN) method which reconstructed the sample space. The new space can not only be characterized by the dynamic characteristics of the original time series but also reflect the characteristics of wind. Finally, BP network can be used to forecast short-term wind speed. The experimental results show that the accuracy of short-term wind speed prediction is improved.

  18. Oak Ridge Health Studies Phase 1 report, Volume 2: Part D, Dose Reconstruction Feasibility Study. Tasks 6, Hazard summaries for important materials at the Oak Ridge Reservation

    Energy Technology Data Exchange (ETDEWEB)

    Bruce, G.M.; Walker, L.B.; Widner, T.E.

    1993-09-01

    The purpose of Task 6 of Oak Ridge Phase I Health Studies is to provide summaries of current knowledge of toxic and hazardous properties of materials that are important for the Oak Ridge Reservation. The information gathered in the course of Task 6 investigations will support the task of focussing any future health studies efforts on those operations and emissions which have likely been most significant in terms of off-site health risk. The information gathered in Task 6 efforts will likely also be of value to individuals evaluating the feasibility of additional health,study efforts (such as epidemiological investigations) in the Oak Ridge area and as a resource for citizens seeking information on historical emissions.

  19. Neuromagnetic source reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, P.S.; Mosher, J.C. [Los Alamos National Lab., NM (United States); Leahy, R.M. [University of Southern California, Los Angeles, CA (United States)

    1994-12-31

    In neuromagnetic source reconstruction, a functional map of neural activity is constructed from noninvasive magnetoencephalographic (MEG) measurements. The overall reconstruction problem is under-determined, so some form of source modeling must be applied. We review the two main classes of reconstruction techniques-parametric current dipole models and nonparametric distributed source reconstructions. Current dipole reconstructions use a physically plausible source model, but are limited to cases in which the neural currents are expected to be highly sparse and localized. Distributed source reconstructions can be applied to a wider variety of cases, but must incorporate an implicit source, model in order to arrive at a single reconstruction. We examine distributed source reconstruction in a Bayesian framework to highlight the implicit nonphysical Gaussian assumptions of minimum norm based reconstruction algorithms. We conclude with a brief discussion of alternative non-Gaussian approachs.

  20. Reconstruction of total grain size distribution of the climactic phase of a long-lasting eruption: the example of the 2008-2013 Chaitén eruption

    Science.gov (United States)

    Alfano, Fabrizio; Bonadonna, Costanza; Watt, Sebastian; Connor, Chuck; Volentik, Alain; Pyle, David M.

    2016-07-01

    The 2008-2013 eruption of Chaitén Volcano (Chile) was a long-lasting eruption whose climactic phase (May 6, 2008) produced a sub-Plinian plume, with height ranging between 14 and 20 km that dispersed to the NE, reaching the Atlantic coast of Argentina. The erupted material was mainly of lithic origin (˜77 wt%), resulting in a unimodal total grain size distribution (TGSD) dominated by coarse ash (77 wt%), with Mdϕ of 2.7 and σϕ of 2.4. Lapilli clasts (>2 mm) dominate the proximal deposit within ~20 km of the vent, while coarse (63 μm-2 mm) and fine ash (modal grain size distributions across the entire deposit. Given that most of the mass is sedimented in proximal areas, results show that possible contributions of later explosive events to the thickness of the distal deposit where layers are less distinguishable (>400 km) do not significantly affect the determination of the TGSD. In contrast, gaps in data sampling in the medial deposit (in particular the gap between 50 and 350 km from vent that coincides with shifts in sedimentation regimes) have large impacts on estimates of TGSD. Particle number distribution for this deposit is characterized by a high power-law exponent (3.0) following a trend very similar to the vesicle size distribution in the juvenile pyroclasts. Although this could be taken to indicate a bubble-driven fragmentation process, we suggest that fragmentation was more likely the result of a shear-driven process because of the predominance of non-vesicular products (lithics and obsidians) and the large fraction of coarse ash in the TGSD.

  1. Analytic image concept combined to SENSE reconstruction

    OpenAIRE

    Yankam Njiwa, J; Baltes, C.; Rudin, M.

    2011-01-01

    Two approaches of reconstructing undersampled partial k-space data, acquired with multiple coils are compared: homodyne detection combined with SENSE (HM_SENSE) and analytic image reconstruction combined with SENSE (AI_SENSE). The latter overcomes limitations of HM_ SENSE by considering aliased images as analytic thus avoiding the need for phase correction required for HM_SENSE. MATERIALS AND METHODS: In vivo imaging experiments were carried out in male Lewis rats using both gradient echo...

  2. Breast reconstruction after mastectomy

    Directory of Open Access Journals (Sweden)

    Daniel eSchmauss

    2016-01-01

    Full Text Available Breast cancer is the leading cause of cancer death in women worldwide. Its surgical approach has become less and less mutilating in the last decades. However, the overall number of breast reconstructions has significantly increased lately. Nowadays breast reconstruction should be individualized at its best, first of all taking into consideration oncological aspects of the tumor, neo-/adjuvant treatment and genetic predisposition, but also its timing (immediate versus delayed breast reconstruction, as well as the patient’s condition and wish. This article gives an overview over the various possibilities of breast reconstruction, including implant- and expander-based reconstruction, flap-based reconstruction (vascularized autologous tissue, the combination of implant and flap, reconstruction using non-vascularized autologous fat, as well as refinement surgery after breast reconstruction.

  3. Reoperative midface reconstruction.

    Science.gov (United States)

    Acero, Julio; García, Eloy

    2011-02-01

    Reoperative reconstruction of the midface is a challenging issue because of the complexity of this region and the severity of the aesthetic and functional sequela related to the absence or failure of a primary reconstruction. The different situations that can lead to the indication of a reoperative reconstructive procedure after previous oncologic ablative procedures in the midface are reviewed. Surgical techniques, anatomic problems, and limitations affecting the reoperative reconstruction in this region of the head and neck are discussed.

  4. Surfaces, Digitisations and Reconstructions

    DEFF Research Database (Denmark)

    2015-01-01

    We present a new digital reconstruction of r-regular sets in three-dimensional Euclidean space. We introduce a vector field and analyse the relation between the topologies of the boundaries of the r-regular set and its reconstruction. This reconstruction can be carried out faster than prior models...

  5. Should I Have Breast Reconstruction?

    Science.gov (United States)

    ... Reconstruction Surgery Breast Cancer Breast Reconstruction Surgery Should I Get Breast Reconstruction Surgery? Women who have surgery ... It usually responds well to treatment. What if I choose not to have breast reconstruction? Many women ...

  6. CURRENT CONCEPTS IN ACL RECONSTRUCTION

    Directory of Open Access Journals (Sweden)

    Freddie H. Fu

    2008-09-01

    's most experienced surgeons to produce a so called "Bible of ACL". The most current concepts not only for the clinical approach but the latest knowledge in basic sciences which the clinical concepts are based on also reviewed including biology, biomechanics, and kinematics. Advances in the diagnostic measures mainly MR imaging are also included. "Current Concepts in ACL Reconstruction" is a complete and the most up-to-date review providing the latest techniques for the treatment of ACL injuries in details, including the perspectives of the most experienced ACL surgeons of the world. Rich illustrations and an accompanying video CD-ROM comprehensively demonstrates the procedures and the techniques described in the book. The differences between single and double-bundle techniques, the technical details in different grafts choices, the technique and approach in the revision surgery are described in detail and explained in the anatomical basis. Pearls, technical pitfalls, personal experience and advices of the most experienced ACL surgeons not only from USA but also from the other pioneer countries of the world in ACL surgery may be the most welcomed parts of the book even by the highly experienced ACL surgeons especially for technically demanding procedures like double-bundle reconstruction. Postoperative rehabilitation described in phases provides the current rehabilitation concept after ACL reconstruction. Outcome measures to assess success after surgery are also reviewed and aspects for future are recommended. Principles and experiences in the navigation technologies in ACL reconstruction are providing the reader new perspectives for future possibilities in diagnosis and treatment. Review of basic sciences, advances in technology and clinical approach from history to future also clearly demonstrates the evolution "where are we and the way to go" and future aspects in the treatment of a thorn ACL

  7. 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.

  8. [Breast reconstruction after mastectomy].

    Science.gov (United States)

    Ho Quoc, C; Delay, E

    2013-02-01

    The mutilating surgery for breast cancer causes deep somatic and psychological sequelae. Breast reconstruction can mitigate these effects and permit the patient to help rebuild their lives. The purpose of this paper is to focus on breast reconstruction techniques and on factors involved in breast reconstruction. The methods of breast reconstruction are presented: objectives, indications, different techniques, operative risks, and long-term monitoring. Many different techniques can now allow breast reconstruction in most patients. Clinical cases are also presented in order to understand the results we expect from a breast reconstruction. Breast reconstruction provides many benefits for patients in terms of rehabilitation, wellness, and quality of life. In our mind, breast reconstruction should be considered more as an opportunity and a positive choice (the patient can decide to do it), than as an obligation (that the patient would suffer). The consultation with the surgeon who will perform the reconstruction is an important step to give all necessary informations. It is really important that the patient could speak again with him before undergoing reconstruction, if she has any doubt. The quality of information given by medical doctors is essential to the success of psychological intervention. This article was written in a simple, and understandable way to help gynecologists giving the best information to their patients. It is maybe also possible to let them a copy of this article, which would enable them to have a written support and would facilitate future consultation with the surgeon who will perform the reconstruction.

  9. 基于相空间重构和柔性神经树的乐器分类%MUSICAL INSTRUMENTS CLASSIFICATION BASED ON PHASE SPACE RECONSTRUCTION AND FLEXIBLE NEURAL TREES

    Institute of Scientific and Technical Information of China (English)

    郅逍遥; 李临生; 郭喆; 郭一娜; 闫庆森

    2015-01-01

    Based on phase space reconstruction theory and principal component analysis theory,we process audio time sequences produced by different musical instruments.A musical instruments classification method is proposed by analysing the high dimensional properties of various instruments and adopting probability density function to describe the difference of each instrument in phase space,and then combining the parameters of probability density function with other timbre features as well as using flexible neural trees (FNT)as the classifier.The FNT can solve highly structure dependent problem of the artificial neural network and also has higher recognition rate.Experiment indicates that compared with BP neural network and support vector machine,this classifier has higher average accuracy rate of classification and lower RMSE value.%基于相空间重构理论和主成分分析理论,对不同乐器产生的音频时间序列进行处理。通过分析各类乐器的高维特性,采用概率密度函数来刻画各个乐器在相空间中的差异,然后将概率密度函数的参数与其他音色特征相结合,采用柔性神经树作为分类器,提出一种新的乐器分类方法。柔性神经树能够解决人工神经网络结构的高度依赖性问题,还具有较高的识别率。实验表明,该分类器与 BP 神经网络和支持向量机比较具有较高的平均分类准确率和较低的均方根误差值。

  10. Holographic microscopy reconstruction in both object and image half spaces with undistorted 3D grid

    CERN Document Server

    Verrier, Nicolas; Tessier, Gilles; Gross, Michel

    2015-01-01

    We propose a holographic microscopy reconstruction method, which propagates the hologram, in the object half space, in the vicinity of the object. The calibration yields reconstructions with an undistorted reconstruction grid i.e. with orthogonal x, y and z axis and constant pixels pitch. The method is validated with an USAF target imaged by a x60 microscope objective, whose holograms are recorded and reconstructed for different USAF locations along the longitudinal axis:-75 to +75 {\\mu}m. Since the reconstruction numerical phase mask, the reference phase curvature and MO form an afocal device, the reconstruction can be interpreted as occurring equivalently in the object or in image half space.

  11. Diffraction Correlation to Reconstruct Highly Strained Particles

    Science.gov (United States)

    Brown, Douglas; Harder, Ross; Clark, Jesse; Kim, J. W.; Kiefer, Boris; Fullerton, Eric; Shpyrko, Oleg; Fohtung, Edwin

    2015-03-01

    Through the use of coherent x-ray diffraction a three-dimensional diffraction pattern of a highly strained nano-crystal can be recorded in reciprocal space by a detector. Only the intensities are recorded, resulting in a loss of the complex phase. The recorded diffraction pattern therefore requires computational processing to reconstruct the density and complex distribution of the diffracted nano-crystal. For highly strained crystals, standard methods using HIO and ER algorithms are no longer sufficient to reconstruct the diffraction pattern. Our solution is to correlate the symmetry in reciprocal space to generate an a priori shape constraint to guide the computational reconstruction of the diffraction pattern. This approach has improved the ability to accurately reconstruct highly strained nano-crystals.

  12. Cosmic Tidal Reconstruction

    CERN Document Server

    Zhu, Hong-Ming; Yu, Yu; Er, Xinzhong; Chen, Xuelei

    2015-01-01

    The gravitational coupling of a long wavelength tidal field with small scale density fluctuations leads to anisotropic distortions of the locally measured small scale matter correlation function. Since the local correlation function is statistically isotropic in the absence of such tidal interactions, the tidal distortions can be used to reconstruct the long wavelength tidal field and large scale density field in analogy with the cosmic microwave background lensing reconstruction. In this paper we present in detail a formalism for the cosmic tidal reconstruction and test the reconstruction in numerical simulations. We find that the density field on large scales can be reconstructed with good accuracy and the cross correlation coefficient between the reconstructed density field and the original density field is greater than 0.9 on large scales ($k\\lesssim0.1h/\\mathrm{Mpc}$). This is useful in the 21cm intensity mapping survey, where the long wavelength radial modes are lost due to foreground subtraction proces...

  13. Ptychographic ultrafast pulse reconstruction

    CERN Document Server

    Spangenberg, D; Brügmann, M H; Feurer, T

    2014-01-01

    We demonstrate a new ultrafast pulse reconstruction modality which is somewhat reminiscent of frequency resolved optical gating but uses a modified setup and a conceptually different reconstruction algorithm that is derived from ptychography. Even though it is a second order correlation scheme it shows no time ambiguity. Moreover, the number of spectra to record is considerably smaller than in most other related schemes which, together with a robust algorithm, leads to extremely fast convergence of the reconstruction.

  14. Classical and Quantum-Mechanical State Reconstruction

    Science.gov (United States)

    Khanna, F. C.; Mello, P. A.; Revzen, M.

    2012-01-01

    The aim of this paper is to present the subject of state reconstruction in classical and in quantum physics, a subject that deals with the experimentally acquired information that allows the determination of the physical state of a system. Our first purpose is to explain a method for retrieving a classical state in phase space, similar to that…

  15. 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...

  16. Delayed breast implant reconstruction

    DEFF Research Database (Denmark)

    Hvilsom, Gitte B.; Hölmich, Lisbet R.; Steding-Jessen, Marianne;

    2012-01-01

    We evaluated the association between radiation therapy and severe capsular contracture or reoperation after 717 delayed breast implant reconstruction procedures (288 1- and 429 2-stage procedures) identified in the prospective database of the Danish Registry for Plastic Surgery of the Breast during...... reconstruction approaches other than implants should be seriously considered among women who have received radiation therapy....

  17. Visually weighted reconstruction of compressive sensing MRI.

    Science.gov (United States)

    Oh, Heeseok; Lee, Sanghoon

    2014-04-01

    Compressive sensing (CS) enables the reconstruction of a magnetic resonance (MR) image from undersampled data in k-space with relatively low-quality distortion when compared to the original image. In addition, CS allows the scan time to be significantly reduced. Along with a reduction in the computational overhead, we investigate an effective way to improve visual quality through the use of a weighted optimization algorithm for reconstruction after variable density random undersampling in the phase encoding direction over k-space. In contrast to conventional magnetic resonance imaging (MRI) reconstruction methods, the visual weight, in particular, the region of interest (ROI), is investigated here for quality improvement. In addition, we employ a wavelet transform to analyze the reconstructed image in the space domain and fully utilize data sparsity over the spatial and frequency domains. The visual weight is constructed by reflecting the perceptual characteristics of the human visual system (HVS), and then applied to ℓ1 norm minimization, which gives priority to each coefficient during the reconstruction process. Using objective quality assessment metrics, it was found that an image reconstructed using the visual weight has higher local and global quality than those processed by conventional methods.

  18. 基于自适应本征维数估计流形学习的相空间重构降噪方法%Phase space reconstruction method for vibration signal's noise reduction based on adaptive intrinsic dimension estimation manifold learning

    Institute of Scientific and Technical Information of China (English)

    马婧华; 汤宝平; 宋涛

    2015-01-01

    Aiming at the problem that the actual engineering vibration signals are interfered by strong noise with strong nonlinear characteristic,a phase space reconstruction method based on adaptive intrinsic dimension estimation manifold learning was proposed.Firstly,one-dimensional time series containing noise were reconstructed into a high dimensional phase space with the phase space reconstruction method.Secondly,the intrinsic dimension of each sample point in the phase space was estimated based on the maximum likelihood estimate (MLE),the adaptive weighted average method was used to calculate the global intrinsic dimension.At last,the manifold learning algorithm and the local tangent space alignment (LTSA)were employed to project the signal containing noise from the high-dimensional phase space into the intrinsic dimensional space of useful signals.After eliminating the noise distributing in the high-dimensional space, the signals were reconstructed back into one-dimensional time series.Lorenz simulation and an example of vibration signals'noise reduction for a wind power generator unit showed that the proposed method has a good performance of nonlinear noise reduction.%针对实际工程领域振动信号噪声干扰大、具有强烈非线性等问题,提出了基于自适应本征维数估计流形学习的相空间重构降噪方法。利用相空间重构将一维含噪时间序列重构到高维相空间;基于极大似然估计法(maximum likelihood estimate,MLE)估计相空间中每个样本点的本征维数并使用自适应加权平均法计算全局本征维数;采用局部切空间排列(Local tangent space Alignment,LTSA)流形学习方法将含噪信号从高维相空间投影到有用信号的本征维空间中,剔除分布在高维空间中的噪声后,重构回一维时间序列。通过 Lorenz 仿真实验和风电机组振动信号降噪实例,证实了该方法具有良好的非线性降噪性能。

  19. Reconstructing Step by Step

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    On May 22,10 days after the Wenchuan earthquake in Sichuan Province,the State Council formed the Post-earthquake Reconstruction Planning Group,deciding to work out a general recon- struction plan within a period of three months. Sichuan was the worst-hit area of China,so reconstruction work there will have a direct influence on how plans proceed in other areas.On July 18,Beijing Review reporter Feng Jianhua interviewed Wang Guangsi,Vice Director of the Sichuan Development and Reform Commission,about Sichuan’s reconstruction plan.

  20. Tensor-based dictionary learning for dynamic tomographic reconstruction

    Science.gov (United States)

    Tan, Shengqi; Zhang, Yanbo; Wang, Ge; Mou, Xuanqin; Cao, Guohua; Wu, Zhifang; Yu, Hengyong

    2015-04-01

    In dynamic computed tomography (CT) reconstruction, the data acquisition speed limits the spatio-temporal resolution. Recently, compressed sensing theory has been instrumental in improving CT reconstruction from far few-view projections. In this paper, we present an adaptive method to train a tensor-based spatio-temporal dictionary for sparse representation of an image sequence during the reconstruction process. The correlations among atoms and across phases are considered to capture the characteristics of an object. The reconstruction problem is solved by the alternating direction method of multipliers. To recover fine or sharp structures such as edges, the nonlocal total variation is incorporated into the algorithmic framework. Preclinical examples including a sheep lung perfusion study and a dynamic mouse cardiac imaging demonstrate that the proposed approach outperforms the vectorized dictionary-based CT reconstruction in the case of few-view reconstruction.

  1. Wavefront reconstruction using computer-generated holograms

    Science.gov (United States)

    Schulze, Christian; Flamm, Daniel; Schmidt, Oliver A.; Duparré, Michael

    2012-02-01

    We propose a new method to determine the wavefront of a laser beam, based on modal decomposition using computer-generated holograms (CGHs). Thereby the beam under test illuminates the CGH with a specific, inscribed transmission function that enables the measurement of modal amplitudes and phases by evaluating the first diffraction order of the hologram. Since we use an angular multiplexing technique, our method is innately capable of real-time measurements of amplitude and phase, yielding the complete information about the optical field. A measurement of the Stokes parameters, respectively of the polarization state, provides the possibility to calculate the Poynting vector. Two wavefront reconstruction possibilities are outlined: reconstruction from the phase for scalar beams and reconstruction from the Poynting vector for inhomogeneously polarized beams. To quantify single aberrations, the reconstructed wavefront is decomposed into Zernike polynomials. Our technique is applied to beams emerging from different kinds of multimode optical fibers, such as step-index, photonic crystal and multicore fibers, whereas in this work results are exemplarily shown for a step-index fiber and compared to a Shack-Hartmann measurement that serves as a reference.

  2. Prairie Reconstruction Initiative Project

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of the Prairie Reconstruction Initiative Advisory Team (PRIAT) is to identify and take steps to resolve uncertainties in the process of prairie...

  3. On TPC cluster reconstruction

    CERN Document Server

    Dydak, F; Nefedov, Y; Wotschack, J; Zhemchugov, A

    2004-01-01

    For a bias-free momentum measurement of TPC tracks, the correct determination of cluster positions is mandatory. We argue in particular that (i) the reconstruction of the entire longitudinal signal shape in view of longitudinal diffusion, electronic pulse shaping, and track inclination is important both for the polar angle reconstruction and for optimum r phi resolution; and that (ii) self-crosstalk of pad signals calls for special measures for the reconstruction of the z coordinate. The problem of 'shadow clusters' is resolved. Algorithms are presented for accepting clusters as 'good' clusters, and for the reconstruction of the r phi and z cluster coordinates, including provisions for 'bad' pads and pads next to sector boundaries, respectively.

  4. Permutationally invariant state reconstruction

    DEFF Research Database (Denmark)

    Moroder, Tobias; Hyllus, Philipp; Tóth, Géza;

    2012-01-01

    Feasible tomography schemes for large particle numbers must possess, besides an appropriate data acquisition protocol, an efficient way to reconstruct the density operator from the observed finite data set. Since state reconstruction typically requires the solution of a nonlinear large-scale opti......Feasible tomography schemes for large particle numbers must possess, besides an appropriate data acquisition protocol, an efficient way to reconstruct the density operator from the observed finite data set. Since state reconstruction typically requires the solution of a nonlinear large...... likelihood and least squares methods, which are the preferred choices in today's experiments. This high efficiency is achieved by greatly reducing the dimensionality of the problem employing a particular representation of permutationally invariant states known from spin coupling combined with convex...

  5. Permutationally invariant state reconstruction

    CERN Document Server

    Moroder, Tobias; Toth, Geza; Schwemmer, Christian; Niggebaum, Alexander; Gaile, Stefanie; Gühne, Otfried; Weinfurter, Harald

    2012-01-01

    Feasible tomography schemes for large particle numbers must possess, besides an appropriate data acquisition protocol, also an efficient way to reconstruct the density operator from the observed finite data set. Since state reconstruction typically requires the solution of a non-linear large-scale optimization problem, this is a major challenge in the design of scalable tomography schemes. Here we present an efficient state reconstruction scheme for permutationally invariant quantum state tomography. It works for all common state-of-the-art reconstruction principles, including, in particular, maximum likelihood and least squares methods, which are the preferred choices in today's experiments. This high efficiency is achieved by greatly reducing the dimensionality of the problem employing a particular representation of permutationally invariant states known from spin coupling combined with convex optimization, which has clear advantages regarding speed, control and accuracy in comparison to commonly employed n...

  6. Reconstructions of eyelid defects

    Directory of Open Access Journals (Sweden)

    Nirmala Subramanian

    2011-01-01

    Full Text Available Eyelids are the protective mechanism of the eyes. The upper and lower eyelids have been formed for their specific functions by Nature. The eyelid defects are encountered in congenital anomalies, trauma, and postexcision for neoplasm. The reconstructions should be based on both functional and cosmetic aspects. The knowledge of the basic anatomy of the lids is a must. There are different techniques for reconstructing the upper eyelid, lower eyelid, and medial and lateral canthal areas. Many a times, the defects involve more than one area. For the reconstruction of the lid, the lining should be similar to the conjunctiva, a cover by skin and the middle layer to give firmness and support. It is important to understand the availability of various tissues for reconstruction. One layer should have the vascularity to support the other layer which can be a graft. A proper plan and execution of it is very important.

  7. Prairie Reconstruction Initiative

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of the Prairie Reconstruction Initiative Advisory Team (PRIAT) is to identify and take steps to resolve uncertainties in the process of prairie...

  8. Breast Reconstruction After Mastectomy

    Science.gov (United States)

    ... It also does not involve cutting of the abdominal muscle and is a free flap. This type of ... NCI fact sheet Mammograms . What are some new developments in breast reconstruction after mastectomy? Oncoplastic surgery. In ...

  9. Head and face reconstruction

    Science.gov (United States)

    ... work together. Head and neck surgeons also perform craniofacial reconstruction operations. The surgery is done while you are deep asleep and pain-free (under general anesthesia ). The surgery may take ...

  10. Primordial density and BAO reconstruction

    CERN Document Server

    Zhu, Hong-Ming; Chen, Xuelei

    2016-01-01

    We present a new method to reconstruct the primordial (linear) density field using the estimated nonlinear displacement field. The divergence of the displacement field gives the reconstructed density field. We solve the nonlinear displacement field in the 1D cosmology and show the reconstruction results. The new reconstruction algorithm recovers a lot of linear modes and reduces the nonlinear damping scale significantly. The successful 1D reconstruction results imply the new algorithm should also be a promising technique in the 3D case.

  11. orbital selective correlation reduce in collapse tetragonal phase of CaFe2(As0.935P0.065)2 and electronic structure reconstruction studied by angel resolved photoemission spectroscopy

    Science.gov (United States)

    Zeng, Lingkun

    We performed an angle-resolved photoemission spectroscopy (ARPES) study of the CaFe2(As0.935P0.065)2 in the collapse tetragonal(CT) phase and uncollapse tetragonal(UCT) phase. We find in the CT phase the electronic correlation dramatically reduces respective to UCT phase. Meanwhile, the reduction of correlation in CT phase show an orbital selective effect: correlation in dxy reduces the most, and then dxz/yz, while the one in dz2-r2 almost keeps the same. In CT phase, almost all bands sink downwards to higher binding energy, leading to the hole like bands around Brillouin zone(BZ) center sink below EF compared with UCT phase. However, the electron pocket around Brillouin Zone(BZ) corner(M) in UCT phase, forms a hole pocket around BZ center(Z point) in CT phase. Moreover, the dxy exhibits larger movement down to higher binding energy, resulting in farther away from dyz/xz and closer to dxy.We propose the electron filling ,namely high spin state in UCT phase to low spin state in CT phase(due to competing between crystal structure field and Hund's coupling), other than the Fermi surface nesting might be responsible for the absent of magnetic ordering.

  12. Augmented Likelihood Image Reconstruction.

    Science.gov (United States)

    Stille, Maik; Kleine, Matthias; Hägele, Julian; Barkhausen, Jörg; Buzug, Thorsten M

    2016-01-01

    The presence of high-density objects remains an open problem in medical CT imaging. Data of projections passing through objects of high density, such as metal implants, are dominated by noise and are highly affected by beam hardening and scatter. Reconstructed images become less diagnostically conclusive because of pronounced artifacts that manifest as dark and bright streaks. A new reconstruction algorithm is proposed with the aim to reduce these artifacts by incorporating information about shape and known attenuation coefficients of a metal implant. Image reconstruction is considered as a variational optimization problem. The afore-mentioned prior knowledge is introduced in terms of equality constraints. An augmented Lagrangian approach is adapted in order to minimize the associated log-likelihood function for transmission CT. During iterations, temporally appearing artifacts are reduced with a bilateral filter and new projection values are calculated, which are used later on for the reconstruction. A detailed evaluation in cooperation with radiologists is performed on software and hardware phantoms, as well as on clinically relevant patient data of subjects with various metal implants. Results show that the proposed reconstruction algorithm is able to outperform contemporary metal artifact reduction methods such as normalized metal artifact reduction.

  13. Speckle removal in phase reconstruction of digital holography for structured surfaces%针对结构表面的数字全息相位重构散斑去除方法

    Institute of Scientific and Technical Information of China (English)

    张晓磊; 张祥朝; 肖虹; 徐敏

    2016-01-01

    In recent years, digital holographic microscopy has attracted intensive attention for its capability of measuring complex shapes. There are two parts in digital holographic microscopy, hologram recording and digital diffractive reconstruction. Speckles are inevitable in the recorded interferometric patterns, thereby polluting the reconstructed surface topographies. Three reconstruction algorithms, i.e. Fresnel transform, Fresnel-wavelets and the proposed Fresnel-NSCT algorithms were compared. Three typical structures, rectangular, spherical and triangular surfaces were adopted for analysis. The performance of the three reconstruction algorithms on speckle removal and feature preservation was investigated comprehensively. Signal-Noise-Ratio (SNR) and Peak-Signal-Noise-Ratio (PSNR) were used as the numerical criteria. It is found that the Fresnel-NSCT algorithm has great superiority over the other two, subsequently it is promising for applications in the diffractive reconstruction of structured surfaces.%近年来,数字全息显微技术在复杂表面测量领域得到了广泛关注。数字全息技术主要分为干涉记录和重构再现两部分。在激光干涉记录中,散斑噪声会严重影响测量结果。因此数字全息相位重构的一项重要工作就是去除散斑噪声,以提高重构精度。分析了带有散斑噪声的几类典型的结构面,比较了菲涅尔衍射算法、基于小波变换的菲涅尔衍射算法和新提出的基于非下采样轮廓波变换的菲涅尔衍射算法三者在散斑去噪和信号保持方面的表现。结果显示:基于非下采样轮廓波变换的菲涅尔衍射重构算法可以有效提取各类结构面的信息,有效实现信噪分离。因此,该方法比现有重构算法可得到更高的重构精度,在结构表面的相位重构方面具有重要应用价值。

  14. Reconstruction of inflation models

    Energy Technology Data Exchange (ETDEWEB)

    Myrzakulov, Ratbay; Sebastiani, Lorenzo [Eurasian National University, Department of General and Theoretical Physics and Eurasian Center for Theoretical Physics, Astana (Kazakhstan); Zerbini, Sergio [Universita di Trento, Dipartimento di Fisica, Trento (Italy); TIFPA, Istituto Nazionale di Fisica Nucleare, Trento (Italy)

    2015-05-15

    In this paper, we reconstruct viable inflationary models by starting from spectral index and tensor-to-scalar ratio from Planck observations. We analyze three different kinds of models: scalar field theories, fluid cosmology, and f(R)-modified gravity. We recover the well-known R{sup 2} inflation in Jordan-frame and Einstein-frame representation, the massive scalar inflaton models and two models of inhomogeneous fluid. A model of R{sup 2} correction to Einstein's gravity plus a ''cosmological constant'' with an exact solution for early-time acceleration is reconstructed. (orig.)

  15. The evolving breast reconstruction

    DEFF Research Database (Denmark)

    Thomsen, Jørn Bo; Gunnarsson, Gudjon Leifur

    2014-01-01

    The aim of this editorial is to give an update on the use of the propeller thoracodorsal artery perforator flap (TAP/TDAP-flap) within the field of breast reconstruction. The TAP-flap can be dissected by a combined use of a monopolar cautery and a scalpel. Microsurgical instruments are generally...... not needed. The propeller TAP-flap can be designed in different ways, three of these have been published: (I) an oblique upwards design; (II) a horizontal design; (III) an oblique downward design. The latissimus dorsi-flap is a good and reliable option for breast reconstruction, but has been criticized...

  16. Vertex Reconstruction in CMS

    CERN Document Server

    Chabanat, E; D'Hondt, J; Vanlaer, P; Prokofiev, K; Speer, T; Frühwirth, R; Waltenberger, W

    2005-01-01

    Because of the high track multiplicity in the final states expected in proton collisions at the LHC experiments, novel vertex reconstruction algorithms are required. The vertex reconstruction problem can be decomposed into a pattern recognition problem ("vertex finding") and an estimation problem ("vertex fitting"). Starting from least-square methods, ways to render the classical algorithms more robust are discussed and the statistical properties of the novel methods are shown. A whole set of different approaches for the vertex finding problem is presented and compared in relevant physics channels.

  17. Upper Eyelid Reconstruction.

    Science.gov (United States)

    Espinoza, Gabriela Mabel; Prost, Angela Michelle

    2016-05-01

    Reconstruction of the upper eyelid is complicated because the eyelid must retain mobility, flexibility, function, and a suitable mucosal surface over the delicate cornea. Defects of the upper eyelid may be due to congenital defects or traumatic injury or follow oncologic resection. This article focuses on reconstruction due to loss of tissue. Multiple surgeries may be needed to reach the desired results, addressing loss of tissue and then loss of function. Each defect is unique and the laxity and availability of surrounding tissue vary. Knowing the most common techniques for repair assists surgeons in the multifaceted planning that takes place.

  18. Ultra short pulse reconstruction software: GROG

    Science.gov (United States)

    Galletti, M.; Galimberti, M.; Giulietti, D.; Curcio, A.

    2016-07-01

    A new algorithmic method based on the 1D Conjugate Gradient Minimization Method, is presented. The purpose is, analyzing experimental FROG/GRENOUILLE traces, to accurately retrieve intensity and phase both in temporal and spectral domain so as to completely characterize an Ultra Short High Power laser pulse. This algorithm shows important features in the reconstruction of many different pulse classes. The employment of this algorithm also permits the inclusion of material response function present in the FROG/GRENOUILLE set-up.

  19. 匹罗卡品致痫大鼠慢性期海马神经元突触重建的实验研究%Neuronal synaptic reconstruction in hippocampus in chronic phase of pilocarpine-treated rats

    Institute of Scientific and Technical Information of China (English)

    易芳; 穆塔森; 龙莉莉; 李艺; 李蜀渝; 吴志国; 肖波

    2011-01-01

    Objective To explore the aberrant formation of excitatory and inhibitory circuit rearrangements of hippoeampus in temporal lobe epilepsy.Methods Pilocarpine-induced animal model was established.At around Day 60 post-modeling,retrograde tracer fluorogold(FG)was injected in vivo into CA1 and CA3 areas of hippocampus by stereotaxic apparatus.Immunohistochemistry of FG was used to observe the aberrant excitatory circuit rearrangements.Double immunofluorescence with NPY(neuropeptide Y)and FG was performed to observe the aberrant inhibitory circuit rearrangements.Results After an iniection of FG into CA1 area.the FG-labeled pyramidal cells could be observed distantly from the zone of dye soread in CA1 area.CA3 area and subiculm.And the FG-labeled non-principal neurons could be seen in stratum oriens of CA1 and hilus in experimental group.Double immunofluorescence revealed that the FG-labeled NPY interneurons were located distantly from the zone of dye spread in CA1 area.CA3 area and hilus in experimental rats.When injection was administered in CA3 area.the FG-labeled pyramidal cells were visible in the whole CA3 area and hilus in both groups.Some pyramidal cells were present in CA1 in experimental group.Also some FG-labeled non-principle cells were foand in hilus and distantly from the zone of dve spread in CA1 area,And the FG-labeled NPY neurons could be seen in hilus in experimental rats.Conclusion Aberrant excitatory and inhibitory synaptic reconstruction exist in hippocampus in chronic phase of temporal lobe epilepsy,including excitatory synaptic connections among pyramidal cells in CA1 area.pyramidal cells between CAl and subiculum and pyramidal cells between CA1 and CA3,inhibitory synaptie connections among dendritie intemeurons in CA1 area,CA3 to CA1,hilus to CA1 and hilus to CA3area,These circuit arrangements may play an important role in the pathogenesis of epilepsy.%目的 探讨颞叶癫痫海马的异常兴奋性与抑制性突触联系变化.方法 建立

  20. Fast MR Spectroscopic Imaging Technologies and Data Reconstruction Methods

    Institute of Scientific and Technical Information of China (English)

    HUANGMin; LUSong-tao; LINJia-rui; ZHANYing-jian

    2004-01-01

    MRSI plays a more and more important role in clinical application. In this paper, we compare several fast MRSI technologies and data reconstruction methods. For the conventional phase encoding MRSI, the data reconstruction using FFT is simple. But the data acquisition is very time consuming and thus prohibitive in clinical settings. Up to now, the MRSI technologies based on echo-planar, spiral trajectories and sensitivity encoding are the fastest in data acquisition, but their data reconstruction is complex. EPSI reconstruction uses shift of odd and even echoes. Spiral SI uses gridding FFT. SENSE-SI, a new approach to reducing the acquisition time, uses the distinct spatial sensitivities of the individual coil elements to recover the missing encoding information. These improvements in data acquisition and image reconstruction provide a potential value of metabolic imaging as a clinical tool.

  1. The PRISM4 (mid-Piacenzian) Palaeoenvironmental Reconstruction

    Science.gov (United States)

    Dowsett, Harry; Dolan, Aisling; Rowley, David; Moucha, Robert; Forte, Alessandro M.; Mitrovica, Jerry X.; Pound, Matthew; Salzmann, Ulrich; Robinson, Marci; Chandler, Mark; Foley, Kevin; Haywood, Alan

    2016-01-01

    The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a paleoenvironmental reconstruction of the mid-Piacenzian (approximately 3 Ma) containing data for paleogeography, land and sea ice, sea-surface temperature, vegetation, soils, and lakes. Our retrodicted paleogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) experiments.

  2. The PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction

    Science.gov (United States)

    Dowsett, Harry J.; Dolan, Aisling M.; Rowley, David; Moucha, Robert; Forte, Alessandro; Mitrovica, Jerry X.; Pound, Matthew; Salzmann, Ulrich; Robinson, Marci M.; Chandler, Mark; Foley, Kevin M.; Haywood, Alan M.

    2016-01-01

    The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a paleoenvironmental reconstruction of the mid-Piacenzian ( ∼ 3 Ma) containing data for paleogeography, land and sea ice, sea-surface temperature, vegetation, soils, and lakes. Our retrodicted paleogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) experiments.

  3. Urogenital Reconstructive Surgery

    DEFF Research Database (Denmark)

    Jakobsen, Lotte Kaasgaard

    Urogenital reconstructive surgery Lotte Kaasgaard Jakobsen1 Professor Henning Olsen1 Overlæge Gitte Hvistendahl1 Professor Karl-Erik Andersson2 1 – Dept. of Urology, Aarhus University Hospital 2 – Dept. of Gynecology and Obstetrics, Aarhus University hospital Background: Congenital obstruction...

  4. Reconstruction of the electron spectrum in a metal hydrogen sulfide

    Science.gov (United States)

    Kudryashov, N. A.; Kutukov, A. A.; Mazur, E. A.

    2017-01-01

    Generalized Eliashberg theory of the normal properties of a metal electron-phonon system with a non constant electron density of states has been used to study the effect of the conduction band reconstruction. The electron density of states of the metallic phase of the hydrogen sulfide renormalized by the strong electron-phonon coupling at a pressure of P = 225 GPa has been calculated. It has been found that the reconstructed conduction band contains a series of narrow energy pockets.

  5. Preparing for Breast Reconstruction Surgery

    Science.gov (United States)

    ... Cancer Breast Reconstruction Surgery Preparing for Breast Reconstruction Surgery Your surgeon can help you know what to ... The plan for follow-up Costs Understanding your surgery costs Health insurance policies often cover most or ...

  6. Iterative reconstruction of magnetic induction using Lorentz transmission electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Phatak, C., E-mail: cd@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Gürsoy, D. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2015-03-15

    Intense ongoing research on complex nanomagnetic structures requires a fundamental understanding of the 3D magnetization and the stray fields around the nano-objects. 3D visualization of such fields offers the best way to achieve this. Lorentz transmission electron microscopy provides a suitable combination of high resolution and ability to quantitatively visualize the magnetization vectors using phase retrieval methods. In this paper, we present a formalism to represent the magnetic phase shift of electrons as a Radon transform of the magnetic induction of the sample. Using this formalism, we then present the application of common tomographic methods particularly the iterative methods, to reconstruct the 3D components of the vector field. We present an analysis of the effect of missing wedge and the limited angular sampling as well as reconstruction of complex 3D magnetization in a nanowire using simulations. - Highlights: • We present a formalism to represent electron-optical magnetic phase shift as a Radon transform of the 3D magnetic induction of the nano-object. • We have analyzed four different tomographic reconstruction methods for vectorial data reconstruction. • Reconstruction methods were tested for varying experimental limitations such as limited tilt range and limited angular sampling. • The analysis showed that Gridrec and SIRT methods performed better with lower errors than other reconstruction methods.

  7. A Novel Method for Satellite CloCk Bias PrediCtion Based on Phase SpaCe ReConstruCtion and Gaussian ProCesses%基于相空间重构与高斯过程的卫星钟差预报

    Institute of Scientific and Technical Information of China (English)

    雷雨; 蔡宏兵; 赵丹宁

    2016-01-01

    提出了一种基于相空间重构与高斯过程预报卫星钟差的新方法。首先根据星载原子钟的物理特性用多项式进行拟合以提取钟差趋势项,并对拟合后的残差进行经验模态分解,作降噪处理;然后以降噪后的残差时间序列的混沌特性为基础,对其进行相空间重构;最后以重构的相空间为基础,运用高斯过程对残差时间序列进行建模预报,再将预报结果加上趋势项,获得最终的钟差预报值。采用 IGS 提供的 GPS 超快速观测钟差建模进行短期预报实验,结果表明,该方法能实时有效地对卫星钟差进行预报,且精度优于超快速预报钟差。%A novel method for satellite clock bias prediction incorporating phase space reconstruction and Gaussian processes(GP)is proposed. Firstly a polynomial model is employed to fit the time-series of clock bias in terms of its characteristics,and then the noise of the polynomial fitting residuals is reduced by the empirical mode decomposition (EMD)algorithm. Secondly,phase space reconstruction is performed for the de-noised residuas according to its chaotic characteristics. Finally,Gaussian processes are established so as to forecast the residuals on the basis of reconstructed phase space,and then the predicted clock bias can be yielded by adding the trend term to the forecasted residuals. The IGS ultra-rapid observed(IGU-O)product is used to set up a clock model,and short-term prediction experiments are carried out. The results show that the proposed method outperforms the IGS ultra-rapid predicted(IGU-P)solutions at least on a daily basis.

  8. Arctic Sea Level Reconstruction

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde

    method.For oceanographic purposes, the altimetric record over the Arctic Ocean is inferiorin quality to that of moderate latitudes, but nonetheless an invaluable set of observations. During this project, newly processed Arctic altimetry from the ERS-1/-2 and Envisat missions has become available......Reconstruction of historical Arctic sea level is very difficult due to the limited coverage and quality of tide gauge and altimetry data in the area. This thesis addresses many of these issues, and discusses strategies to help achieve a stable and plausible reconstruction of Arctic sea level from...... 1950 to today.The primary record of historical sea level, on the order of several decades to a few centuries, is tide gauges. Tide gauge records from around the world are collected in the Permanent Service for Mean Sea Level (PSMSL) database, and includes data along the Arctic coasts. A reasonable...

  9. Autologous Costochondral Microtia Reconstruction.

    Science.gov (United States)

    Patel, Sapna A; Bhrany, Amit D; Murakami, Craig S; Sie, Kathleen C Y

    2016-04-01

    Reconstruction with autologous costochondral cartilage is one of the mainstays of surgical management of congenital microtia. We review the literature, present our current technique for microtia reconstruction with autologous costochondral graft, and discuss the evolution of our technique over the past 20 years. We aim to minimize donor site morbidity and create the most durable and natural appearing ear possible using a stacked framework to augment the antihelical fold and antitragal-tragal complex. Assessment of outcomes is challenging due to the paucity of available objective measures with which to evaluate aesthetic outcomes. Various instruments are used to assess outcomes, but none is universally accepted as the standard. The challenges we continue to face are humbling, but ongoing work on tissue engineering, application of 3D models, and use of validated questionnaires can help us get closer to achieving a maximal aesthetic outcome.

  10. Stochastic reconstruction of sandstones

    Science.gov (United States)

    Manwart; Torquato; Hilfer

    2000-07-01

    A simulated annealing algorithm is employed to generate a stochastic model for a Berea sandstone and a Fontainebleau sandstone, with each a prescribed two-point probability function, lineal-path function, and "pore size" distribution function, respectively. We find that the temperature decrease of the annealing has to be rather quick to yield isotropic and percolating configurations. A comparison of simple morphological quantities indicates good agreement between the reconstructions and the original sandstones. Also, the mean survival time of a random walker in the pore space is reproduced with good accuracy. However, a more detailed investigation by means of local porosity theory shows that there may be significant differences of the geometrical connectivity between the reconstructed and the experimental samples.

  11. Reconstructing the Tengger calendar

    Directory of Open Access Journals (Sweden)

    Ian Proudfoot

    2008-12-01

    Full Text Available The survival of an Indic calendar among the Tengger people of the Brama highlands in east Java opens a window on Java’s calendar history. Its hybrid form reflects accommodations between this non-Muslim Javanese group and the increasingly dominant Muslim Javanese culture. Reconstruction is challenging because of this hybridity, because of inconsistencies in practice, and because the historical evidence is sketchy and often difficult to interpret.

  12. Propagation phasor approach for holographic image reconstruction

    Science.gov (United States)

    Luo, Wei; Zhang, Yibo; Göröcs, Zoltán; Feizi, Alborz; Ozcan, Aydogan

    2016-03-01

    To achieve high-resolution and wide field-of-view, digital holographic imaging techniques need to tackle two major challenges: phase recovery and spatial undersampling. Previously, these challenges were separately addressed using phase retrieval and pixel super-resolution algorithms, which utilize the diversity of different imaging parameters. Although existing holographic imaging methods can achieve large space-bandwidth-products by performing pixel super-resolution and phase retrieval sequentially, they require large amounts of data, which might be a limitation in high-speed or cost-effective imaging applications. Here we report a propagation phasor approach, which for the first time combines phase retrieval and pixel super-resolution into a unified mathematical framework and enables the synthesis of new holographic image reconstruction methods with significantly improved data efficiency. In this approach, twin image and spatial aliasing signals, along with other digital artifacts, are interpreted as noise terms that are modulated by phasors that analytically depend on the lateral displacement between hologram and sensor planes, sample-to-sensor distance, wavelength, and the illumination angle. Compared to previous holographic reconstruction techniques, this new framework results in five- to seven-fold reduced number of raw measurements, while still achieving a competitive resolution and space-bandwidth-product. We also demonstrated the success of this approach by imaging biological specimens including Papanicolaou and blood smears.

  13. Canal Wall Reconstruction Mastoidectomy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To investigate the advantages of canal wall reconstruction (CWR) mastoidectomy, a single-stage technique for cholesteatoma removal and posterior external canal wall reconstruction, over the open and closed procedures in terms of cholesteatoma recurrence. Methods: Between June 2002 and December 2005, 38 patients (40 ears) with cholesteatoma were admited to Sun Yat-Sen Memorial Hospital and received surgical treatments. Of these patients, 25 were male with ages ranging between 11 and 60 years (mean = 31.6 years) and 13 were female with ages ranging between 20 and 65 years (mean = 38.8 years). Canal wall reconstruction (CWR)mastoidectomy was performed in 31 ears and canal wall down (CWD) mastoidectomy in 9 ears. Concha cartilage was used for ear canal wall reconstruction in 22 of the 31 CWR procedures and cortical mastoid bone was used in the remaining 9 cases. Results At 0.5 to 4 years follow up, all but one patients remained free of signs of cholesteatoma recurrence, i.e., no retraction pocket or cholesteatoma matrix. One patient, a smoker, needed revision surgery due to cholesteatoma recurrence 1.5 year after the initial operation. The recurrence rate was therefore 3.2% (1/31). Cholesteatoma recurrence was monitored using postoperative CT scans whenever possible. In the case that needed a revision procedure, a retraction pocket was identified by otoendoscopy in the pars flacida area that eventually evolved into a cholesteatoma. A pocket extending to the epitympanum filled with cholesteatoma matrix was confirmed during the revision operation, A decision to perform a modified mastoidectomy was made as the patient refused to quit smoking. The mean air-bone gap in pure tone threshold was 45 dB before surgery and 25 dB after (p < 0.05). There was no difference between using concha cartilage and cortical mastoid bone for the reconstruction regarding air-bone gap improvement, CT findings and otoendoscopic results. Conclusion CWR mastoidectomy can be used for

  14. Posteromedial Corner Reconstruction

    Science.gov (United States)

    Ferrer, Gonzalo; Leon, Agustín; Wirth, Hans; Mena, Adolfo; Tuca, María José; Espinoza, Gonzalo

    2017-01-01

    Objective: Report the experience, after 1-year follow-up, of 30 patients who underwent anatomical knee reconstruction of posteromedial corner (PMC) injuries, using La Prade´s Technique. Methods: Retrospective cohort study of 30 consecutive patients with PMC injuries operated between November 2010 and May 2014 by the same surgical team. Inclusion criteria: patients with clinical presentation and images (stress radiographs and MRI) compatible with PMC injury, who maintained a grade III chronic instability in spite of at least 3 months of orthopedic treatment, who were reconstructed using La Prade’s anatomical technique, and completed at least 12 months of follow-up. Exclusion criteria: discordance between clinical and image studies, grade I or II medial instability, and surgery performed through a different technique. Data was collected by reviewing the electronic files and images. Functional scores (IKDC and Lysholm) were applied and registered in the preoperative evaluation, and then 6 and 12 months after surgery. Results: Thirty patients (28 men and 2 women) met the inclusion criteria. Mean age was 43 years (24-69). The vast majority (28 patients) had a high-energy mechanism of injury. Twenty patients were diagnosed in the acute setting, while 10 had a delayed diagnosis after poor results of concomitant ligament reconstructions. With the exception of 2 patients, who presented with isolated PMC injury, the majority had associated injuries as detailed: 11 cases had PMC + anterior cruciate ligament (ACL) injury, 3 patients had PMC + posterior cruciate ligament (PCL) injury, 3 patients had PMC + meniscal tears, 9 patients had PMC + ACL + PCL injuries, and there were 2 cases of PMC + ACL + PCL + lateral collateral ligament injuries. Mean time for PMC reconstruction surgery was 5 months (range 2-32). Lysholm and IKDC scores were 18,2 (2-69) and 24,3 (9,2-52,9) respectively in the preoperative setting, improving to 76,7 (44-94) and 70,7 (36,8-95,4) after 1-year follow

  15. Phase error correction in wavefront curvature sensing via phase retrieval

    DEFF Research Database (Denmark)

    Almoro, Percival; Hanson, Steen Grüner

    2008-01-01

    Wavefront curvature sensing with phase error correction system is carried out using phase retrieval based on a partially-developed volume speckle field. Various wavefronts are reconstructed: planar, spherical, cylindrical, and a wavefront passing through the side of a bare optical fiber. Spurious...

  16. Resolution extension and exit wave reconstruction in complex HREM.

    Science.gov (United States)

    Hsieh, Wen-Kuo; Chen, Fu-Rong; Kai, Ji-Jung; Kirkland, A I

    2004-01-01

    Direct methods in real and reciprocal space are developed for structural reversion. The direct method in real space involves the use of a novel method to retrieve the phase in the image plane using transport of intensity equation/maximum entropy method (TIE/MEM) and exit wave reconstruction by self-consistent propagation. Since the exit wave is restored from the complex signal in the image planes, no image model between the exit wave and image is assumed. The structural information in the reconstructed exit wave is then further extended by a "complex" maximum entropy method as a direct method in reciprocal space to extrapolate the phase to higher frequencies.

  17. Reconstruction in Time-Bandwidth Compression Systems

    CERN Document Server

    Chan, Jacky; Asghari, Mohammad H; Jalali, Bahram

    2014-01-01

    Recently it has been shown that the intensity time-bandwidth product of optical signals can be engineered to match that of the data acquisition instrument. In particular, it is possible to slow down an ultrafast signal, resulting in compressed RF bandwidth - a similar benefit to that offered by the Time-Stretch Dispersive Fourier Transform (TS-DFT) - but with reduced temporal record length leading to time-bandwidth compression. The compression is implemented using a warped group delay dispersion leading to non-uniform time stretching of the signal's intensity envelope. Decoding requires optical phase retrieval and reconstruction of the input temporal profile, for the case where information of interest is resides in the complex field. In this paper, we present results on the general behavior of the reconstruction process and its dependence on the signal-to-noise ratio. We also discuss the role of chirp in the input signal.

  18. Automatic selection of an optimal systolic and diastolic reconstruction windows for dual-source CT coronary angiography

    Science.gov (United States)

    Seifarth, H.; Puesken, M.; Wienbeck, S.; Maintz, D.; Heindel, W.; Juergens, K.-U.

    2008-03-01

    Purpose: To assess the performance of a motion map algorithm to automatically determine the optimal systolic and diastolic reconstruction window for coronary CT Angiography using Dual Source CT. Materials and Methods: Dual Source coronary CT angiography data sets (Somatom Definition, Siemens Medical Solutions) from 50 consecutive patients were included in the analysis. Optimal systolic and diastolic reconstruction windows were determined using a motion map algorithm (BestPhase, Siemens Medical Solutions). Additionally data sets were reconstructed in 5% steps throughout the RR-interval. For each major vessel (RCA, LAD and LCX) an optimal systolic and diastolic reconstruction window was manually determined by two independent readers using volume rendering displays. Image quality was rated using a five-point scale (1 = no motion artifacts, 5 = severe motion artifacts over entire length of the vessel). Results: The mean heart rate during the scan was 72.4bpm (+/-15.8bpm). Median systolic and diastolic reconstruction windows using the BestPhase algorithm were at 37% and 73% RR. The median manually selected systolic reconstruction window was 35 %, 30% and 35% for RCA, LAD, and LCX. For all vessels the median observer selected diastolic reconstruction window was 75%. Mean image quality using the BestPhase algorithm was 2.4 +/-0.9 for systolic reconstructions and 1.9 +/-1.1 for diastolic reconstructions. Using the manual approach, the mean image quality was 1.9 +/-0.5 and 1.7 +/-0.8 respectively. There was a significant difference in image quality between automatically and manually determined systolic reconstructions (p<0.01) but there was no significant difference in image quality in diastolic reconstructions. Conclusion: Automatic determination of the optimal reconstruction interval using the BestPhase algorithm is feasible and yields reconstruction windows similar to observer selected reconstruction windows. In diastolic reconstructions overall image quality is similar

  19. [Rehabilitation after arthroscopic anterior cruciate ligament reconstruction].

    Science.gov (United States)

    Smékal, D; Kalina, R; Urban, J

    2006-12-01

    Rehabilitation is an important part of therapy in patients who have had arthroscopic anterior cruciate ligament reconstruction. A well-designed rehabilitation program avoids potential graft damage and speeds up patients' return to their full function level. The course of rehabilitation depends on the type of surgery, mode of fixation and possible co-existing injury to the knee's soft tissues. The rehabilitation program presented here is based on the present-day knowledge of neurophysiological and biomechanical principles and is divided into five phases. In the pre-operative phase (I), the main objective is to prepare patients for surgery in terms of maximum muscle strength and range of motion. It also includes providing full information on the procedure. In the early post-operative phase (II) we are concerned with pain alleviation and reduction of knee edema. After suture removal we begin with soft techniques for the patella and post-operative physical therapy to reduce scarring. In the next post-operative phase (III) patients are able to walk with their full weight on the extremity operated on, and we continue doing exercises that improve flexor/extensor co-contraction. In this phase we also begin with exercises improving the patient's proprioceptive and sensorimotor functions. In the late post-operative phase (IV) we go on with exercises promoting proprioception of both lower extremities with the aim of increasing muscle control of the knee joints. In the convalescent phase (V) patients gradually return to their sports activities.

  20. Reconstruction of microstructure in catalyst layer of PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Rong, F.; Huang, C.; Liu, Z.S.; Song, D.T.; Wang, Q.P. [National Research Council of Canada, Vancouver, BC (Canada). Inst. for Fuel Cell Innovation

    2007-07-01

    Different microstructures of catalyst layer (CL) have been experimentally studied to improve the performance of the proton membrane exchange (PEM) fuel cell. These experiments have revealed the microstructure in catalyst layers can be considered as one kind of random media and its changes will have significant influence on the performance of PEM fuel cell. This paper presented the results of a study that applied the filtering method and stochastic optimization to reconstruct the microstructure based on the statistical information of catalyst layers. The filtering method changes the Gauss distributed signals to three-phase microstructure reconstruction while the stochastic optimization method, refines the microstructure reconstruction to fit the statistical features of experimental images. Based on the physical properties as well as the mass ratio, the statistical feature extraction based on image process of catalyst layer and the reconstruction procedure was proposed. The paper discussed evaluation of phase statistical information, initial reconstruction based on filtering method, stochastic optimization for reconstruction, as well as a summary of the study. It was concluded that the results of the filtering method as the initial pattern of stochastic optimization could make the error (between the final result and the experimental target) less than that of the random initial value and saved the computational time simultaneously. 13 refs., 6 figs.

  1. Direct reconstruction of enhanced signal in computed tomography perfusion

    Science.gov (United States)

    Li, Bin; Lyu, Qingwen; Ma, Jianhua; Wang, Jing

    2016-04-01

    High imaging dose has been a concern in computed tomography perfusion (CTP) as repeated scans are performed at the same location of a patient. On the other hand, signal changes only occur at limited regions in CT acquired at different time points. In this work, we propose a new reconstruction strategy by effectively utilizing the initial phase high-quality CT to reconstruct the later phase CT acquired with a low-dose protocol. In the proposed strategy, initial high-quality CT is considered as a base image and enhanced signal (ES) is reconstructed directly by minimizing the penalized weighted least-square (PWLS) criterion. The proposed PWLS-ES strategy converts the conventional CT reconstruction into a sparse signal reconstruction problem. Digital and anthropomorphic phantom studies were performed to evaluate the performance of the proposed PWLS-ES strategy. Both phantom studies show that the proposed PWLS-ES method outperforms the standard iterative CT reconstruction algorithm based on the same PWLS criterion according to various quantitative metrics including root mean squared error (RMSE) and the universal quality index (UQI).

  2. Highly efficient solid state catalysis by reconstructed (001) Ceria surface

    Energy Technology Data Exchange (ETDEWEB)

    Solovyov, VF; Ozaki, T; Atrei, A; Wu, LJ; Al-Mahboob, A; Sadowski, JT; Tong, X; Nykypanchuk, D; Li, Q

    2014-04-10

    Substrate engineering is a key factor in the synthesis of new complex materials. The substrate surface has to be conditioned in order to minimize the energy threshold for the formation of the desired phase or to enhance the catalytic activity of the substrate. The mechanism of the substrate activity, especially of technologically relevant oxide surfaces, is poorly understood. Here we design and synthesize several distinct and stable CeO2 (001) surface reconstructions which are used to grow epitaxial films of the high-temperature superconductor YBa2Cu3O7. The film grown on the substrate having the longest, fourfold period, reconstruction exhibits a twofold increase in performance over surfaces with shorter period reconstructions. This is explained by the crossover between the nucleation site dimensions and the period of the surface reconstruction. This result opens a new avenue for catalysis mediated solid state synthesis.

  3. Computed Tomography of Transverse Phase Space

    Energy Technology Data Exchange (ETDEWEB)

    Watts, A. [Fermilab; Johnstone, C. [Fermilab; Johnstone, J. [Fermilab

    2016-09-19

    Two computed tomography techniques are explored to reconstruct beam transverse phase space using both simulated beam and multi-wire profile data in the Fermilab Muon Test Area ("MTA") beamline. Both Filtered Back-Projection ("FBP") and Simultaneous Algebraic Reconstruction Technique ("SART") algorithms [2] are considered and compared. Errors and artifacts are compared as a function of each algorithm’s free parameters, and it is shown through simulation and MTA beamline profiles that SART is advantageous for reconstructions with limited profile data.

  4. Magni: A Python Package for Compressive Sampling and Reconstruction of Atomic Force Microscopy Images

    DEFF Research Database (Denmark)

    Oxvig, Christian Schou; Pedersen, Patrick Steffen; Arildsen, Thomas

    2014-01-01

    provides researchers in compressed sensing with a selection of algorithms for reconstructing undersampled general images, and offers a consistent and rigorous way to efficiently evaluate the researchers own developed reconstruction algorithms in terms of phase transitions. The package also serves......Magni is an open source Python package that embraces compressed sensing and Atomic Force Microscopy (AFM) imaging techniques. It provides AFM-specific functionality for undersampling and reconstructing images from AFM equipment and thereby accelerating the acquisition of AFM images. Magni also...

  5. Martensitic phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Petry, W.; Neuhaus, J. [Techn. Universitaet Muenchen, Physik Department E13, Munich (Germany)

    1996-11-01

    Many elements transform from a high temperature bcc phase to a more dense packed temperature phase. The great majority of these transitions are of 1st order, displacive and reconstructive. The lattice potentials which govern these martensitic transitions can be probed by inelastic neutron scattering, thereby answering fundamental questions like : Will the transition be announced by dynamical or static fluctuations? What are the trajectories for the displacements needed for the transformation? Does the vibrational entropy stabilize the high temperature phase? Are the unusual transport properties in these materials related to their ability to transform? (author) 17 figs., 1 tab., 46 refs.

  6. Reconstruction in Fourier space

    Science.gov (United States)

    Burden, A.; Percival, W. J.; Howlett, C.

    2015-10-01

    We present a fast iterative fast Fourier transform (FFT) based reconstruction algorithm that allows for non-parallel redshift-space distortions (RSDs). We test our algorithm on both N-body dark matter simulations and mock distributions of galaxies designed to replicate galaxy survey conditions. We compare solenoidal and irrotational components of the redshift distortion and show that an approximation of this distortion leads to a better estimate of the real-space potential (and therefore faster convergence) than ignoring the RSD when estimating the displacement field. Our iterative reconstruction scheme converges in two iterations for the mock samples corresponding to Baryon Oscillation Spectroscopic Survey CMASS Data Release 11 when we start with an approximation of the RSD. The scheme takes six iterations when the initial estimate, measured from the redshift-space overdensity, has no RSD correction. Slower convergence would be expected for surveys covering a larger angle on the sky. We show that this FFT based method provides a better estimate of the real-space displacement field than a configuration space method that uses finite difference routines to compute the potential for the same grid resolution. Finally, we show that a lognormal transform of the overdensity, used as a proxy for the linear overdensity, is beneficial in estimating the full displacement field from a dense sample of tracers. However, the lognormal transform of the overdensity does not perform well when estimating the displacements from sparser simulations with a more realistic galaxy density.

  7. LHCb; LHCb Jet Reconstruction

    CERN Multimedia

    Augusto, O

    2012-01-01

    The Large Hadron Collider (LHC) is the most powerful particle accelerator in the world. It has been designed to collide proton beams at an energy up to 14 TeV in the center of mass. In 2011, the data taking was done with a center of mass energy of 7 TeV, the instant luminosity has reached values greater than $4 \\times 10^{32} cm^{-2} s^{-1}$ and the integrated luminosity reached the value of 1.02 $fb^{-1}$ on the LHCb. The jet reconstruction is fundamental to observe events that can be used to test pertubative QCD (pQCD). It also provides a way to observe standard model channels and searches for new physics like SUSY. The anti-kt algorithm is a jet reconstruction algorithm that is based on the distance of the particles on the space $\\eta \\times \\phi$ and on the transverse momentum of particles. To maximize the energy resolution all information about the trackers and the calo...

  8. Reconstructing Experiences through Sketching

    CERN Document Server

    Karapanos, Evangelos; Hassenzahl, Marc

    2009-01-01

    This paper presents iScale, a survey tool that aims at eliciting users' experiences with a product from memory. iScale employs sketching in imposing a process in the reconstruction of one's experiences. Two versions of iScale, the Constructive and the Value-Account iScale, were motivated by two distinct theories on how people reconstruct emotional experiences from memory. These two versions were tested in two separate studies. Study 1 aimed at providing qualitative insight into the use of iScale and compared its performance to that of free-hand sketching. Study 2 compared the two iScale versions to a control condition: that of reporting one's experiences without employing any form of sketching. Significant differences between iScale and the "no-sketching" tool were found. Overall, iScale resulted in a) an increase in the number of experience reports that subjects provided, b) an increase in the amount of contextual information for the reported experiences, and c) an increase in subjects' accuracy in recalling...

  9. Biomaterials for craniofacial reconstruction

    Directory of Open Access Journals (Sweden)

    Neumann, Andreas

    2009-01-01

    Full Text Available Biomaterials for reconstruction of bony defects of the skull comprise of osteosynthetic materials applied after osteotomies or traumatic fractures and materials to fill bony defects which result from malformation, trauma or tumor resections. Other applications concern functional augmentations for dental implants or aesthetic augmentations in the facial region.For ostheosynthesis, mini- and microplates made from titanium alloys provide major advantages concerning biocompatibility, stability and individual fitting to the implant bed. The necessity of removing asymptomatic plates and screws after fracture healing is still a controversial issue. Risks and costs of secondary surgery for removal face a low rate of complications (due to corrosion products when the material remains in situ. Resorbable osteosynthesis systems have similar mechanical stability and are especially useful in the growing skull.The huge variety of biomaterials for the reconstruction of bony defects makes it difficult to decide which material is adequate for which indication and for which site. The optimal biomaterial that meets every requirement (e.g. biocompatibility, stability, intraoperative fitting, product safety, low costs etc. does not exist. The different material types are (autogenic bone and many alloplastics such as metals (mainly titanium, ceramics, plastics and composites. Future developments aim to improve physical and biological properties, especially regarding surface interactions. To date, tissue engineered bone is far from routine clinical application.

  10. Virtual 3-D Facial Reconstruction

    Directory of Open Access Journals (Sweden)

    Martin Paul Evison

    2000-06-01

    Full Text Available Facial reconstructions in archaeology allow empathy with people who lived in the past and enjoy considerable popularity with the public. It is a common misconception that facial reconstruction will produce an exact likeness; a resemblance is the best that can be hoped for. Research at Sheffield University is aimed at the development of a computer system for facial reconstruction that will be accurate, rapid, repeatable, accessible and flexible. This research is described and prototypical 3-D facial reconstructions are presented. Interpolation models simulating obesity, ageing and ethnic affiliation are also described. Some strengths and weaknesses in the models, and their potential for application in archaeology are discussed.

  11. Exercises in PET Image Reconstruction

    Science.gov (United States)

    Nix, Oliver

    These exercises are complementary to the theoretical lectures about positron emission tomography (PET) image reconstruction. They aim at providing some hands on experience in PET image reconstruction and focus on demonstrating the different data preprocessing steps and reconstruction algorithms needed to obtain high quality PET images. Normalisation, geometric-, attenuation- and scatter correction are introduced. To explain the necessity of those some basics about PET scanner hardware, data acquisition and organisation are reviewed. During the course the students use a software application based on the STIR (software for tomographic image reconstruction) library 1,2 which allows them to dynamically select or deselect corrections and reconstruction methods as well as to modify their most important parameters. Following the guided tutorial, the students get an impression on the effect the individual data precorrections have on image quality and what happens if they are forgotten. Several data sets in sinogram format are provided, such as line source data, Jaszczak phantom data sets with high and low statistics and NEMA whole body phantom data. The two most frequently used reconstruction algorithms in PET image reconstruction, filtered back projection (FBP) and the iterative OSEM (ordered subset expectation maximation) approach are used to reconstruct images. The exercise should help the students gaining an understanding what the reasons for inferior image quality and artefacts are and how to improve quality by a clever choice of reconstruction parameters.

  12. The reconstruction software for the MICE scintillating fibre trackers

    CERN Document Server

    Dobbs, A; Long, K; Santos, E; Uchida, M A; Kyberd, P; Heidt, C; Blot, S; Overton, E

    2016-01-01

    The Muon Ionization Cooling Experiment (MICE) will demonstrate the principle of muon beam phase-space reduction via ionization cooling. Muon beam cooling will be required for the proposed Neutrino Factory or Muon Collider. The phase-space before and after the cooling cell must be measured precisely. This is achieved using two scintillating-fibre trackers, each placed in a solenoidal magnetic field. This paper describes the software reconstruction for the fibre trackers: the GEANT4 based simulation; the implementation of the geometry; digitisation; space-point reconstruction; pattern recognition; and the final track fit based on a Kalman filter. The performance of the software is evaluated by means of Monte Carlo studies and the precision of the final track reconstruction is evaluated.

  13. Performance of muon reconstruction including Alignment Position Errors for 2016 Collision Data

    CERN Document Server

    CMS Collaboration

    2016-01-01

    From 2016 Run muon reconstruction is using non-zero Alignment Position Errors to account for the residual uncertainties of muon chambers' positions. Significant improvements are obtained in particular for the startup phase after opening/closing the muon detector. Performance results are presented for real data and MC simulations, related to both the offline reconstruction and the High-Level Trigger.

  14. Biomatrices for bladder reconstruction.

    Science.gov (United States)

    Lin, Hsueh-Kung; Madihally, Sundar V; Palmer, Blake; Frimberger, Dominic; Fung, Kar-Ming; Kropp, Bradley P

    2015-03-01

    There is a demand for tissue engineering of the bladder needed by patients who experience a neurogenic bladder or idiopathic detrusor overactivity. To avoid complications from augmentation cystoplasty, the field of tissue engineering seeks optimal scaffolds for bladder reconstruction. Naturally derived biomaterials as well as synthetic and natural polymers have been explored as bladder substitutes. To improve regenerative properties, these biomaterials have been conjugated with functional molecules, combined with nanotechology, or seeded with exogenous cells. Although most studies reported complete and functional bladder regeneration in small-animal models, results from large-animal models and human clinical trials varied. For functional bladder regeneration, procedures for biomaterial fabrication, incorporation of biologically active agents, introduction of nanotechnology, and application of stem-cell technology need to be standardized. Advanced molecular and medical technologies such as next generation sequencing and magnetic resonance imaging can be introduced for mechanistic understanding and non-invasive monitoring of regeneration processes, respectively.

  15. Reconstructability analysis of epistasis.

    Science.gov (United States)

    Zwick, Martin

    2011-01-01

    The literature on epistasis describes various methods to detect epistatic interactions and to classify different types of epistasis. Reconstructability analysis (RA) has recently been used to detect epistasis in genomic data. This paper shows that RA offers a classification of types of epistasis at three levels of resolution (variable-based models without loops, variable-based models with loops, state-based models). These types can be defined by the simplest RA structures that model the data without information loss; a more detailed classification can be defined by the information content of multiple candidate structures. The RA classification can be augmented with structures from related graphical modeling approaches. RA can analyze epistatic interactions involving an arbitrary number of genes or SNPs and constitutes a flexible and effective methodology for genomic analysis.

  16. TOLLAN-XICOCOTITLAN: A RECONSTRUCTED CITY BY AUGMENTED REALITY (EXTENDED

    Directory of Open Access Journals (Sweden)

    M. en C. Martha Rosa Cordero López

    2014-10-01

    Full Text Available Work In Terminal presents the analysis, design, implementation and results of Reconstruction Xicocotitlan Tollan-through augmented reality (Extended, which will release information about the Toltec capital supplemented by presenting an overview of the main premises of the Xicocotitlan Tollan city supported dimensional models based on the augmented reality technique showing the user a virtual representation of buildings in Tollan phase.

  17. RECONSTRUCTION OF TOLLANXICOCOTITLAN CITY BY AUGMENTED REALITY (EXTENDED

    Directory of Open Access Journals (Sweden)

    M. en C. Martha Rosa Cordero Lopez

    2014-05-01

    Full Text Available Work In Terminal presents the analysis, design, implementation and results of Reconstruction Xicocotitlan Tollan-through augmented reality (Extended, which will release information about the Toltec capital supplemented by presenting an overview of the main premises of the Xicocotitlan Tollan city supported dimensional models based on the augmented reality technique showing the user a virtual representation of buildings in Tollan phase.

  18. Rapid haplotype reconstruction in predigrees with dense marker maps

    NARCIS (Netherlands)

    Windig, J.J.; Meuwissen, T.H.E.

    2004-01-01

    Reconstruction of marker phases is not straightforward when parents are untyped. In these cases information from other relatives has to be used. In dense marker maps, however, the space of possible haplotype configurations tends to be too large for procedures such as Monte Carlo Markov chains (MCMC)

  19. Jiangxi Hengfeng Nanfang Copper Reconstruction & Extension Project Signed

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>The reconstruction & extension project (phase II) of Nanfang Copper has been recently signed. With an investment of RMB 0.8 billion, the project is expected to produce 50,000 tons of anode copper and electrolytic copper respectively per year with output value of RMB 3 billion, and will further enhance development

  20. The criterion of pulse reconstruction quality based on Wigner representation

    NARCIS (Netherlands)

    Yeremenko, S.; Baltuska, A.; Pshenichnikov, M.S; Wiersma, D. A.

    2000-01-01

    We propose a new criterion for the assessment of ultrashort pulse reconstruction quality. Our idea is based on the use of a two-dimensional Wigner representation of the electric field. This allows introducing a single measure to represent the quality of both phase and amplitude retrieval. The new cr

  1. Reconstructing Jets and Missing Transverse Energy using the CMS Detector

    CERN Document Server

    Cavanaugh, Richard J

    2006-01-01

    In 2007, the Large Hadron Collider (LHC) will circulate and collide proton-proton beams for the first time. The Compact Muon Solenoid (CMS) is one of four experiments at the LHC and is entering the final phases of construction and initial phases of commissioning. This report discusses the expected performance of reconstructing jets and missing transverse energy using the CMS Detector. In addition, strategies for calibrating the energy scale using real data are presented.

  2. CRUCIATE LIGAMENT RECONSTRUCTION

    Directory of Open Access Journals (Sweden)

    A. V. Korolev

    2016-01-01

    Full Text Available Purpose: To evaluate long-term results of meniscal repair during arthroscopic ACL reconstruction.Materials and methods: 45 patients who underwent meniscal repair during arthroscopic ACL reconstruction between 2007 and 2013 by the same surgeon were included in the study. In total, fifty meniscus were repaired (26 medial and 24 lateral. Procedures included use of one up to four Fast-Fix implants (Smith & Nephew. In five cases both medial and lateral meniscus were repaired. Cincinnati, IKDC and Lysholm scales were used for long-term outcome analysis.Results: 19 male and 26 female patients were included in the study aging from 15 to 59 years (mean age 33,2±1,5. Median time from injury to surgical procedure was zero months (ranging zero to one. Mean time from surgery to scale analysis was 55,9±3 months (ranged 20-102. Median Cincinnati score was 97 (ranged 90-100, with excellent results in 93% of cases (43 patients and good results in 7% (3 patients. Median IKDC score was 90,8 (ranged 86,2-95,4, with excellent outcomes in 51% of cases (23 patients, good in 33% (15 patients and satisfactory in 16% (7 patients. Median Lysholm score was 95 (ranged 90-100, with excellent outcomes in 76% of cases (34 patients and good in 24% (11 patients. Authors identified no statistical differences when comparing survey results in age, sex and time from trauma to surgery.Conclusions: Results of the present study match the data from orthopedic literature that prove meniscal repair as a safe and efficient procedure with good and excellent outcomes. All-inside meniscal repair can be used irrespectively of patients' age and is efficient even in case of delayed procedures.

  3. Ptychographic reconstruction of attosecond pulses

    CERN Document Server

    Lucchini, M; Ludwig, A; Gallmann, L; Keller, U; Feurer, T

    2015-01-01

    We demonstrate a new attosecond pulse reconstruction modality which uses an algorithm that is derived from ptychography. In contrast to other methods, energy and delay sampling are not correlated, and as a result, the number of electron spectra to record is considerably smaller. Together with the robust algorithm, this leads to a more precise and fast convergence of the reconstruction.

  4. Are temperature reconstructions regionally biased?

    CERN Document Server

    Bothe, O

    2012-01-01

    Are temperature reconstructions possibly biased due to regionally differing density of utilized proxy-networks? This question is assessed utilizing a simple process-based forward model of tree growth in the virtual reality of two simulations of the climate of the last millennium with different amplitude of solar forcing variations. The pseudo-tree ring series cluster in high latitudes of the northern hemisphere and east Asia. Only weak biases are found for the full network. However, for a strong solar forcing amplitude the high latitudes indicate a warmer first half of the last millennium while mid-latitudes and Asia were slightly colder than the extratropical hemispheric average. Reconstruction skill is weak or non-existent for two simple reconstruction schemes, and comparison of virtual reality target and reconstructions reveals strong deficiencies. The temporal resolution of the proxies has an influence on the reconstruction task and results are sensitive to the construction of the proxy-network. Existing ...

  5. Wideband pulse reconstruction from sparse spectral-amplitude data. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Casey, K.F.; Baertlein, B.A.

    1993-01-01

    Methods are investigated for reconstructing a wideband time-domain pulse waveform from a sparse set of samples of its frequency-domain amplitude spectrum. Approaches are outlined which comprise various means of spectrum interpolation followed by phase retrieval. Methods for phase retrieval are reviewed, and it is concluded that useful results can only be obtained by assuming a minimum-phase solution. Two reconstruction algorithms` are proposed. The first is based upon the use of Cauchy`s technique for estimating the amplitude spectrum in the form of a ratio of polynomials. The second uses B-spline interpolation among the sampled values to reconstruct this spectrum. Reconstruction of the time-domain waveform via inverse Fourier transformation follows, based on the assumption of minimum phase. Representative numerical results are given.

  6. Blob-enhanced reconstruction technique

    Science.gov (United States)

    Castrillo, Giusy; Cafiero, Gioacchino; Discetti, Stefano; Astarita, Tommaso

    2016-09-01

    A method to enhance the quality of the tomographic reconstruction and, consequently, the 3D velocity measurement accuracy, is presented. The technique is based on integrating information on the objects to be reconstructed within the algebraic reconstruction process. A first guess intensity distribution is produced with a standard algebraic method, then the distribution is rebuilt as a sum of Gaussian blobs, based on location, intensity and size of agglomerates of light intensity surrounding local maxima. The blobs substitution regularizes the particle shape allowing a reduction of the particles discretization errors and of their elongation in the depth direction. The performances of the blob-enhanced reconstruction technique (BERT) are assessed with a 3D synthetic experiment. The results have been compared with those obtained by applying the standard camera simultaneous multiplicative reconstruction technique (CSMART) to the same volume. Several blob-enhanced reconstruction processes, both substituting the blobs at the end of the CSMART algorithm and during the iterations (i.e. using the blob-enhanced reconstruction as predictor for the following iterations), have been tested. The results confirm the enhancement in the velocity measurements accuracy, demonstrating a reduction of the bias error due to the ghost particles. The improvement is more remarkable at the largest tested seeding densities. Additionally, using the blobs distributions as a predictor enables further improvement of the convergence of the reconstruction algorithm, with the improvement being more considerable when substituting the blobs more than once during the process. The BERT process is also applied to multi resolution (MR) CSMART reconstructions, permitting simultaneously to achieve remarkable improvements in the flow field measurements and to benefit from the reduction in computational time due to the MR approach. Finally, BERT is also tested on experimental data, obtaining an increase of the

  7. Porcelain three-dimensional shape reconstruction and its color reconstruction

    Science.gov (United States)

    Yu, Xiaoyang; Wu, Haibin; Yang, Xue; Yu, Shuang; Wang, Beiyi; Chen, Deyun

    2013-01-01

    In this paper, structured light three-dimensional measurement technology was used to reconstruct the porcelain shape, and further more the porcelain color was reconstructed. So the accurate reconstruction of the shape and color of porcelain was realized. Our shape measurement installation drawing is given. Because the porcelain surface is color complex and highly reflective, the binary Gray code encoding is used to reduce the influence of the porcelain surface. The color camera was employed to obtain the color of the porcelain surface. Then, the comprehensive reconstruction of the shape and color was realized in Java3D runtime environment. In the reconstruction process, the space point by point coloration method is proposed and achieved. Our coloration method ensures the pixel corresponding accuracy in both of shape and color aspects. The porcelain surface shape and color reconstruction experimental results completed by proposed method and our installation, show that: the depth range is 860 ˜ 980mm, the relative error of the shape measurement is less than 0.1%, the reconstructed color of the porcelain surface is real, refined and subtle, and has the same visual effect as the measured surface.

  8. 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.

  9. Phase Diversity and Polarization Augmented Techniques for Active Imaging

    Science.gov (United States)

    2007-03-01

    APDI) reconstruction algorithm similar to that of Seldin et al. [45]. The resulting algorithm is essentially a hybrid between multi- frame blind...aberration parameters. 4.3.4 Multi-Frame Phase Diversity Reconstruction. Seldin and Paxman expanded phase-diversity image reconstruction for Poisson...given value of f . Seldin and Paxman [45] observed that the algorithm tended to converge to local max- ima that did not represent the known object. In

  10. Practical algorithms for simulation and reconstruction of digital in-line holograms

    CERN Document Server

    Latychevskaia, Tatiana

    2014-01-01

    Here, we present practical methods for simulation and reconstruction of in-line digital holograms recorded with plane and spherical waves. The algorithms described here are applicable to holographic imaging of an object exhibiting absorption as well as phase shifting properties. Optimal parameters, related to distances, sampling rate, and other factors for successful simulation and reconstruction of holograms are evaluated and criteria for the achievable resolution are worked out. Moreover, we show that the numerical procedures for the reconstruction of holograms recorded with plane and spherical waves are identical under certain conditions. Experimental examples of holograms and their reconstructions are also discussed.

  11. Semantically Documenting Virtual Reconstruction: Building a Path to Knowledge Provenance

    Science.gov (United States)

    Bruseker, G.; Guillem, A.; Carboni, N.

    2015-08-01

    The outcomes of virtual reconstructions of archaeological monuments are not just images for aesthetic consumption but rather present a scholarly argument and decision making process. They are based on complex chains of reasoning grounded in primary and secondary evidence that enable a historically probable whole to be reconstructed from the partial remains left in the archaeological record. This paper will explore the possibilities for documenting and storing in an information system the phases of the reasoning, decision and procedures that a modeler, with the support of an archaeologist, uses during the virtual reconstruction process and how they can be linked to the reconstruction output. The goal is to present a documentation model such that the foundations of evidence for the reconstructed elements, and the reasoning around them, are made not only explicit and interrogable but also can be updated, extended and reused by other researchers in future work. Using as a case-study the reconstruction of a kitchen in a Roman domus in Grand, we will examine the necessary documentation requirements, and the capacity to express it using semantic technologies. For our study we adopt the CIDOC-CRM ontological model, and its extensions CRMinf, CRMBa and CRMgeo as a starting point for modelling the arguments and relations.

  12. Bioluminescence tomography based on the phase approximation model

    OpenAIRE

    Cong, W; Wang, G.

    2010-01-01

    A reconstruction method of bioluminescence sources is proposed based on a phase approximation model. Compared with the diffuse approximation, this phase approximation model more correctly predicts bioluminescence photon propagation in biological tissues, so that bioluminescence tomography can accurately locate and quantify the distribution of bioluminescence sources. The compressive sensing (CS) technique is applied to regularize the inverse source reconstruction to enhance numerical stabilit...

  13. LOFAR sparse image reconstruction

    NARCIS (Netherlands)

    Garsden, H.; et al., [Unknown; van der Horst, A.; Markoff, S.; Rowlinson, A.; Swinbank, J.; Wise, M.W.

    2015-01-01

    Context. The LOw Frequency ARray (LOFAR) radio telescope is a giant digital phased array interferometer with multiple antennas distributed in Europe. It provides discrete sets of Fourier components of the sky brightness. Recovering the original brightness distribution with aperture synthesis forms a

  14. Reconstructions with identical filling (RIF) of the heart: a physiological approach to image reconstruction in coronary CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Reinartz, S.D.; Diefenbach, B.S.; Kuhl, C.K.; Mahnken, A.H. [University Hospital, RWTH Aachen University, Department of Diagnostic and Interventional Radiology, Aachen (Germany); Allmendinger, T. [Siemens Healthcare Sector, Department of Computed Tomography, Forchheim (Germany)

    2012-12-15

    To compare image quality in coronary artery computed tomography angiography (cCTA) using reconstructions with automated phase detection and Reconstructions computed with Identical Filling of the heart (RIF). Seventy-four patients underwent ECG-gated dual source CT (DSCT) between November 2009 and July 2010 for suspected coronary heart disease (n = 35), planning of transcatheter aortic valve replacement (n = 34) or evaluation of ventricular function (n = 5). Image data sets by the RIF formula and automated phase detection were computed and evaluated with the AHA 15-segment model and a 5-grade Likert scale (1: poor, 5: excellent quality). Subgroups regarding rhythm (sinus rhythm = SR; arrhythmia = ARR) and potential premedication were evaluated by a per-segment, per-vessel and per-patient analysis. RIF significantly improved image quality in 10 of 15 coronary segments (P < 0.05). More diagnostic segments were provided by RIF regarding the entire cohort (n = 693 vs. 590, P < 0.001) and all of the subgroups (e.g. ARR: n = 143 vs. 72, P < 0.001). In arrhythmic patients (n = 19), more diagnostic vessels (e.g. LAD: n = 10 vs. 3; P < 0.014) and complete data sets (n = 7 vs. 1; P < 0.001) were produced. RIF reconstruction is superior to automatic diastolic non-edited reconstructions, especially in arrhythmic patients. RIF theory provides a physiological approach for determining the optimal image reconstruction point in ECG-gated CT angiography. (orig.)

  15. Evidence-Based ACL Reconstruction

    Directory of Open Access Journals (Sweden)

    E. Carlos RODRIGUEZ-MERCHAN

    2015-01-01

    Full Text Available There is controversy in the literature regarding a number of topics related to anterior cruciate ligament (ACLreconstruction. The purpose of this article is to answer the following questions: 1 Bone patellar tendon bone (BPTB reconstruction or hamstring reconstruction (HR; 2 Double bundle or single bundle; 3 Allograft or authograft; 4 Early or late reconstruction; 5 Rate of return to sports after ACL reconstruction; 6 Rate of osteoarthritis after ACL reconstruction. A Cochrane Library and PubMed (MEDLINE search of systematic reviews and meta-analysis related to ACL reconstruction was performed. The key words were: ACL reconstruction, systematic reviews and meta-analysis. The main criteria for selection were that the articles were systematic reviews and meta-analysesfocused on the aforementioned questions. Sixty-nine articles were found, but only 26 were selected and reviewed because they had a high grade (I-II of evidence. BPTB-R was associated with better postoperative knee stability but with a higher rate of morbidity. However, the results of both procedures in terms of functional outcome in the long-term were similar. The double-bundle ACL reconstruction technique showed better outcomes in rotational laxity, although functional recovery was similar between single-bundle and double-bundle. Autograft yielded better results than allograft. There was no difference between early and delayed reconstruction. 82% of patients were able to return to some kind of sport participation. 28% of patients presented radiological signs of osteoarthritis with a follow-up of minimum 10 years.

  16. Reconstruction of B mesons

    Science.gov (United States)

    Albrecht, H.; Binder, U.; Böckmann, P.; Gläser, R.; Harder, G.; Lembke-Koppitz, I.; Schmidt-Parzefall, W.; Schröder, H.; Schulz, H. D.; Wurth, R.; Yagil, A.; Donker, J. P.; Drescher, A.; Kamp, D.; Matthiesen, U.; Scheck, H.; Spaan, B.; Spengler, J.; Wegener, D.; Gabriel, J. C.; Schubert, K. R.; Stiewe, J.; Strahl, K.; Waldi, R.; Weseler, S.; Edwards, K. W.; Frisken, W. R.; Gilkinson, D. J.; Gingrich, D. M.; Kapitza, H.; Kim, P. C. H.; Kutschke, R.; Macfarlane, D. B.; McKenna, J. A.; McLean, K. W.; Nilsson, A. W.; Orr, R. S.; Padley, P.; Parsons, J. A.; Patel, P. M.; Prentice, J. D.; Seywerd, H. C. J.; Swain, J. D.; Tsipolitis, G.; Yoon, T.-S.; Yun, J. C.; Ammar, R.; Coppage, D.; Davis, R.; Kanekal, S.; Kwak, N.; Boštjančič, B.; Kernel, G.; Pleško, M.; Jönsson, L.; Babaev, A.; Danilov, M.; Golutvin, A.; Gorelov, I.; Lubimov, V.; Matveev, V.; Nagovitsin, V.; Ryltsov, V.; Semenov, A.; Shevchenko, V.; Soloshenko, V.; Tchistilin, V.; Tichomirov, I.; Zaitzev, Yu.; Childers, R.; Darden, C. W.; Oku, Y.; Gennow, H.; Argus Collaboration

    1987-02-01

    B mesons have been reconstructed in five decay channels of the type B→D ∗±nπ(n=1,2,3) using data accumulated by the ARGUS experiment at the e +e - storage ring DORIS II at DESY. In total, we find 40 neutral B mesons above a background of 15±6 events with a mass of (5278.2±1.0±3.0) MeV/ c2 and 32 charged B mesons above a background of 17±6 events with a mass of (5275.8±1.3±3.0) MeV/ c2. The decays overlineB0D∗+π -π 0, overlineB0D∗+π -π -π +, and B-→ D∗+π -π -π 0 have been observed for the first time. We find substantially smaller branching ratios for the decay modes overlineB0→ D∗+π - and B-→ D∗+π -π - than previously published by the CLEO collaboration.

  17. Reconstructing human evolution

    CERN Document Server

    Cavalli-Sforza, M

    1999-01-01

    One can reconstruct human evolution using modern genetic data and models based on the mathematical theory of evolution and its four major factors : mutation, natural selection, statistical fluctuations in finite populations (random genetic drift), and migration. Archaeology gives some help on the major dates and events of the process. Chances of studying ancient DNA are very limited but there have been a few successful results. Studying DNA instead of proteins, as was done until a few years ago, and in particular the DNA of mitochondria and of the Y chromosome which are transmitted, respectively, by the maternal line and the paternal line, has greatly simplified the analysis. It is now possible to carry the analysis on individuals, while earlier studies were of necessity based on populations. Also the evolution of ÒcultureÓ (i.e. what we learn from others), in particular that of languages, gives some help and can be greatly enlightened by genetic studies. Even though it is largely based on mechanisms of mut...

  18. Facial Reconstruction and Rehabilitation.

    Science.gov (United States)

    Guntinas-Lichius, Orlando; Genther, Dane J; Byrne, Patrick J

    2016-01-01

    Extracranial infiltration of the facial nerve by salivary gland tumors is the most frequent cause of facial palsy secondary to malignancy. Nevertheless, facial palsy related to salivary gland cancer is uncommon. Therefore, reconstructive facial reanimation surgery is not a routine undertaking for most head and neck surgeons. The primary aims of facial reanimation are to restore tone, symmetry, and movement to the paralyzed face. Such restoration should improve the patient's objective motor function and subjective quality of life. The surgical procedures for facial reanimation rely heavily on long-established techniques, but many advances and improvements have been made in recent years. In the past, published experiences on strategies for optimizing functional outcomes in facial paralysis patients were primarily based on small case series and described a wide variety of surgical techniques. However, in the recent years, larger series have been published from high-volume centers with significant and specialized experience in surgical and nonsurgical reanimation of the paralyzed face that have informed modern treatment. This chapter reviews the most important diagnostic methods used for the evaluation of facial paralysis to optimize the planning of each individual's treatment and discusses surgical and nonsurgical techniques for facial rehabilitation based on the contemporary literature.

  19. Image Interpolation Through Surface Reconstruction

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ling; LI Xue-mei

    2013-01-01

    Reconstructing an HR (high-resolution) image which preserves the image intrinsic structures from its LR ( low-resolution) counterpart is highly challenging. This paper proposes a new surface reconstruction algorithm applied to image interpolation. The interpolation surface for the whole image is generated by putting all the quadratic polynomial patches together. In order to eliminate the jaggies of the edge, a new weight function containing edge information is incorporated into the patch reconstruction procedure as a constraint. Extensive experimental results demonstrate that our method produces better results across a wide range of scenes in terms of both quantitative evaluation and subjective visual quality.

  20. Adaptive simultaneous algebraic reconstruction technique for retrieving refractive index profiles of optical fiber

    Science.gov (United States)

    Chang, Zheng; Huang, Sujuan; Wang, Tingyun; Shang, Yi; Zhang, Qianwu; Yan, Cheng; Zou, Fang

    2016-09-01

    An efficient adaptive simultaneous algebraic reconstruction technique (ASART) to calculate optical fiber refractive index profiles is proposed based on phase difference curves obtained by digital holography technique. We develop adaptive relaxation parameter (ARP) on simultaneous algebraic reconstruction technique (SART) to increase the convergence speed and improve the reconstruction accuracy. A formula of ARP is derived mathematically and multilevel scheme (MLS) is used to increase convergence speed in the first iteration. Experimental results show the proposed ASART convergences over 40% faster than SART and achieve significantly higher reconstruction accuracy. Experimental verification shows that ASART is more efficient than SART and filtered back projection in image reconstruction, especially with few projection views. The running time of ASART is much shorter than that of SART, and ASART needs fewer iteration numbers to obtain the same reconstruction effects. In addition, it can be used to measure optical fibers with various diameters that cannot be measured with S14 refractive index profiler (S14).

  1. Tomographic reconstruction of time-bin-entangled qudits

    Science.gov (United States)

    Nowierski, Samantha J.; Oza, Neal N.; Kumar, Prem; Kanter, Gregory S.

    2016-10-01

    We describe an experimental implementation to generate and measure high-dimensional time-bin-entangled qudits. Two-photon time-bin entanglement is generated via spontaneous four-wave mixing in single-mode fiber. Unbalanced Mach-Zehnder interferometers transform selected time bins to polarization entanglement, allowing standard polarization-projective measurements to be used for complete quantum state tomographic reconstruction. Here we generate maximally entangled qubits (d =2 ) , qutrits (d =3 ) , and ququarts (d =4 ) , as well as other phase-modulated nonmaximally entangled qubits and qutrits. We reconstruct and verify all generated states using maximum-likelihood estimation tomography.

  2. The recording of digital hologram at short distance and reconstruction using convolution approach

    Institute of Scientific and Technical Information of China (English)

    Chen Li-Ping; LU Xiao-Xu

    2009-01-01

    By adopting in-line lensless Fourier setup and phase-shifting technique, we recorded the phase-shifting digital hologram at short distance. As the Fresnel diffraction condition is no longer valid, the convolution approach is chosen for the reconstruction. However, the simulated reference wave for the reconstruction would suffer from severe under-sampling due to the comparatively large pixel size. To solve this problem, sine-interpolation is introduced to get the pixel-size of the hologram reduced prior to the reconstruction. The experimental results show that an object image of high fidelity is obtained with this method.

  3. A novel random phase-shifting digital holographic microscopy method

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper proposes a new method that reconstructs the information of specimen by using random phase shift step in digital holographic microscopy (DHM). The principles of the method are described and discussed in detail. In practical experiment, because the phase shifter is neither perfectly linear nor calibrated, digital holograms with inaccurate phase shift step are recorded by the charge-coupled device (CCD). The phase could be accurately reconstructed from the recorded digital holograms by using the random phase-shifting algorithm, which makes up for reconstructed phase error caused by ordinary phase-shifting algorithm. The phase aberration compensation is also discussed. In order to verify the flexibility of the proposed method, numerical simulation of random phase-shifting DHM was carried out. The simulation results illustrated that the presented method is effective when the phase shift step is unknown or random in DHM.

  4. Investigation of smooth wave fronts using SLM-based phase retrieval and a phase diffuser

    CERN Document Server

    Agour, Mostafa; Falldorf, Claas

    2012-01-01

    A phase retrieval technique using a spatial light modulator (SLM) and a phase diffuser for a fast reconstruction of smooth wave fronts is demonstrated experimentally. Diffuse illumination of a smooth test object with the aid of a phase diffuser (maximum phase shift, Df = 0.85p) results in a significant diversity in the intensity measurements which, in turn, is beneficial for a non-stagnating iterative phase reconstruction. The use of the SLM enables accurate and fast speckle intensity recording and active correction of misalignments in the setup. The effectiveness of the technique is demonstrated in the optical testing of lenses.

  5. Short-term Wind Speed Forecasting Based on Phase Space Reconstruction and Self-Adaptive Support Vector Machine%基于相空间重构及自适应支持向量机的短期风速预测

    Institute of Scientific and Technical Information of China (English)

    杨洪深

    2014-01-01

    The wind is strong random and intermittent, which leads to large scale wind power integration will seriously affect the safe and stable operation of power system and power quality. Wind speed and more accurate prediction can reduce the adverse impact of wind power on the grid, and provide reliable basis for power griddispatching. Based on the chaotic property analysis of wind speed and phase space reconstruction, using adaptive short-term wind speed forecasting support vector machine, the results indicate that the prediction accuracy of this method is higher than that of BP, RBF prediction model.%风速具有较强的随机性和间歇性,导致大规模风电接入电网会严重影响电力系统的安全稳定运行以及电能质量。较为准确的风速预测可以降低风能对电网的不利影响,为电网运行调度提供可靠的依据。在对风速进行混沌属性分析及相空间重构的基础上,采用自适应支持向量机进行短期风速预测,结果表明该方法的预测精度高于BP、RBF等预测模型。

  6. Oak Ridge Health Studies Phase 1 report, Volume 2: Part A, Dose Reconstruction Feasibility Study. Tasks 1 and 2, A summary of historical activities on the Oak Ridge Reservation with emphasis on information concerning off-site emissions of hazardous materials

    Energy Technology Data Exchange (ETDEWEB)

    Bruce, G.M.; Buddenbaum, J.E.; Lamb, J.K.; Widner, T.E.

    1993-09-01

    The Phase I feasibility study has focused on determining the availability of information for estimating exposures of the public to chemicals and radionuclides released as a result of historical operation of the facilities at the Oak Ridge Reservation (ORR). The estimation of such past exposures is frequently called dose reconstruction. The initial project tasks, Tasks 1 and 2 were designed to identify and collect information that documents the history of activities at the ORR that resulted in the release of contamination and to characterize the availability of data that could be used to estimate the magnitude of the contaminant releases or public exposures. A history of operations that are likely to have generated off-site releases has been documented as a result of Task 1 activities. The activities required to perform this task involved the extensive review of historical operation records and interviews with present and past employees as well as other knowledgeable individuals. The investigation process is documented in this report. The Task 1 investigations have led to the documentation of an overview of the activities that have taken place at each of the major complexes, including routine operations, waste management practices, special projects, and accidents and incidents. Historical activities that appear to warrant the highest priority in any further investigations were identified based on their likely association with off-site emissions of hazardous materials as indicated by the documentation reviewed or information obtained in interviews.

  7. Phases and Phase Transitions

    Science.gov (United States)

    Gitterman, Moshe

    2014-09-01

    In discussing phase transitions, the first thing that we have to do is to define a phase. This is a concept from thermodynamics and statistical mechanics, where a phase is defined as a homogeneous system. As a simple example, let us consider instant coffee. This consists of coffee powder dissolved in water, and after stirring it we have a homogeneous mixture, i.e., a single phase. If we add to a cup of coffee a spoonful of sugar and stir it well, we still have a single phase -- sweet coffee. However, if we add ten spoonfuls of sugar, then the contents of the cup will no longer be homogeneous, but rather a mixture of two homogeneous systems or phases, sweet liquid coffee on top and coffee-flavored wet sugar at the bottom...

  8. Hologram-reconstruction signal enhancement

    Science.gov (United States)

    Mezrich, R. S.

    1977-01-01

    Principle of heterodyne detection is used to combine object beam and reconstructed virtual image beam. All light valves in page composer are opened, and virtual-image beam is allowed to interfere with light from valves.

  9. Arapahoe NWR diversion reconstruction : Preliminary

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a preliminary plan for a diversion reconstruction for Hubbard #2. Oklahoma #1, Dryer, Hill and Crowder sites on the Arapahoe National Wildlife Refuge.

  10. Rational reconstructions of modern physics

    CERN Document Server

    Mittelstaedt, Peter

    2013-01-01

    Newton’s classical physics and its underlying ontology are loaded with several metaphysical hypotheses that cannot be justified by rational reasoning nor by experimental evidence. Furthermore, it is well known that some of these hypotheses are not contained in the great theories of Modern Physics, such as the theory of Special Relativity and Quantum Mechanics. This book shows that, on the basis of Newton’s classical physics and by rational reconstruction, the theory of Special Relativity as well as Quantum Mechanics can be obtained by partly eliminating or attenuating the metaphysical hypotheses. Moreover, it is shown that these reconstructions do not require additional hypotheses or new experimental results. In the second edition the rational reconstructions are completed with respect to General Relativity and Cosmology. In addition, the statistics of quantum objects is elaborated in more detail with respect to the rational reconstruction of quantum mechanics. The new material completes the approach of t...

  11. Phase extraction from fringe pattern via light propagation.

    Science.gov (United States)

    Zhu, Wenhua; Chen, Lei; Zheng, Donghui; Zhang, Rui; Han, Zhigang

    2017-01-10

    A phase demodulation method via light propagation is proposed, where one or two fringe patterns are viewed as the superposition of complex amplitudes, and then the phase is reconstructed by separating the light field via light propagation. Simulation and experimental results indicated that the proposed method can extract the phase from a single shot effectively, thereby realizing dynamic phase retrieval. In addition, the accuracy of phase reconstruction can be improved by adding another fringe pattern with an unknown phase shift. The carrier requirement is relatively low, and, thus, the proposed method can be applied to the measurements with an environment disturbance, an inaccurate phase shift, and the requirement of a high speed capture.

  12. Hybrid single-beam reconstruction technique for slow and fast varying wave fields.

    Science.gov (United States)

    Falaggis, Konstantinos; Kozacki, Tomasz; Kujawinska, Malgorzata

    2015-06-01

    An iterative single-beam wave field reconstruction technique that employs both non-paraxial, wave propagation based and paraxial deterministic phase retrieval techniques is presented. This approach overcomes two major obstacles that exist in the current state of the art techniques: iterative methods do not reconstruct slowly varying wave fields due to slow convergence and stagnation, and deterministic methods have paraxial limits, making the reconstructions of quickly varying object features impossible. In this work, a hybrid approach is reported that uses paraxial wave field corrections within iterative phase retrieval solvers. This technique is suitable for cases ranging from slow to fast varying wave fields, and unlike the currently available methods, can also reconstruct measurement objects with different regions of both slowly and quickly varying object features. It is further shown that this technique gives a higher accuracy than current single-beam phase retrieval techniques, and in comparison to the iterative methods, has a higher convergence speed.

  13. Investigation of the extraordinary null reconstruction phenomenon in polarization volume hologram.

    Science.gov (United States)

    Wang, J; Kang, G; Wu, A; Liu, Y; Zang, J; Li, P; Tan, X; Shimura, T; Kuroda, K

    2016-01-25

    Polarization holography is the superposition of differently polarized beams. Due to its ability to record the polarization states, some extraordinary optical phenomena were found in the polarization holography. For example, the recently reported null-reconstruction phenomenon in polarization volume hologram is odd for the conventional holography which only records the amplitude and phase. In this paper, we perform a thorough investigation of the null reconstruction of polarization hologram recorded by orthogonal circularly polarized waves. To explore the mechanism behind this phenomenon, an interferometry was built to measure the phase difference between the same polarized components within the reconstructed wave. The phase difference of π was secured in our experiment, indicating a destructive interfering effect, which nicely explains the extraordinary null reconstruction observed in the polarization hologram.

  14. Three-dimensional Reconstruction and Homogenization of Heterogeneous Materials Using Statistical Correlation Functions and FEM

    Energy Technology Data Exchange (ETDEWEB)

    Baniassadi, Majid; Mortazavi, Behzad; Hamedani, Amani; Garmestani, Hamid; Ahzi, Said; Fathi-Torbaghan, Madjid; Ruch, David; Khaleel, Mohammad A.

    2012-01-31

    In this study, a previously developed reconstruction methodology is extended to three-dimensional reconstruction of a three-phase microstructure, based on two-point correlation functions and two-point cluster functions. The reconstruction process has been implemented based on hybrid stochastic methodology for simulating the virtual microstructure. While different phases of the heterogeneous medium are represented by different cells, growth of these cells is controlled by optimizing parameters such as rotation, shrinkage, translation, distribution and growth rates of the cells. Based on the reconstructed microstructure, finite element method (FEM) was used to compute the effective elastic modulus and effective thermal conductivity. A statistical approach, based on two-point correlation functions, was also used to directly estimate the effective properties of the developed microstructures. Good agreement between the predicted results from FEM analysis and statistical methods was found confirming the efficiency of the statistical methods for prediction of thermo-mechanical properties of three-phase composites.

  15. Free Flap Procedures for Reconstruction After Head and Neck Cancer.

    Science.gov (United States)

    Kini, Erin

    2015-12-01

    Patients with head and neck cancer are seeking improved surgical procedures to avoid severe defects that result from head and neck cancer resection. Free flap reconstruction provides vascularized tissue that has been transferred from a distant donor site on a patient's body to a recipient site, markedly improving wound closure and protecting structures of the head and neck. This article discusses free flap procedures for reconstruction after head and neck cancer resection, including the following procedure phases: airway protection and neck dissections, tumor resection, flap harvest, microvascular anastomosis of the flap, and reconstruction and closure. The article also explains specific risk factors for patients undergoing free flap procedures that have been identified in the literature and include procedure length, hypothermia, and pressure injuries. Each of these factors is discussed regarding its specific effect on this patient population, and the nursing interventions to reduce these risks are identified.

  16. Muon reconstruction performance in ATLAS at Run 2

    CERN Document Server

    Lesage, Arthur; The ATLAS collaboration

    2016-01-01

    This article documents the performance of the ATLAS muon identification and reconstruction using the first LHC dataset recorded at $\\sqrt{s} = 13$ TeV in 2015. Using a large sample of $J/\\psi\\rightarrow\\mu\\mu$ and $Z\\rightarrow\\mu\\mu$ decays, measurements of the reconstruction efficiency, as well as of the momentum scale and resolution, are presented and compared to Monte Carlo simulations. The reconstruction efficiency is measured to be close to $99\\%$ over most of the covered phase space ($|\\eta| 2.2$, the $p_{\\text{T}}$ resolution for a typical muon from $Z\\rightarrow\\mu\\mu$ decays is $2.9\\%$ while the precision on the momentum scale for low-$p_{\\text{T}}$ muons from $J/\\psi\\rightarrow\\mu\\mu$ decays is about $0.2\\%$.

  17. Improving outcomes in aesthetic facial reconstruction.

    Science.gov (United States)

    Hofer, Stefan O P; Mureau, Marc A M

    2009-07-01

    Aesthetic facial reconstruction is a challenging art. Improving outcomes in aesthetic facial reconstruction requires a thorough understanding of the basic principles of the functional and aesthetic requirements for facial reconstruction. From there, further refinement and attention to detail can be provided. This paper discusses basic principles of aesthetic facial reconstruction.

  18. On $\\mathfrak{I}$-reconstruction Property

    OpenAIRE

    L. K. Vashisht; Khattar, Geetika

    2013-01-01

    Reconstruction property in Banach spaces introduced and studied by Casazza and Christensen in [1]. In this paper we introduce reconstruction property in Banach spaces which satisfy $\\mathfrak{I}$-property. A characterization of reconstruction property in Banach spaces which satisfy $\\mathfrak{I}$-property in terms of frames in Banach spaces is obtained. Banach frames associated with reconstruction property are discussed.

  19. Super-resolution Phase Tomography

    KAUST Repository

    Depeursinge, Christian

    2013-04-21

    Digital Holographic Microscopy (DHM) yields reconstructed complex wavefields. It allows synthesizing the aperture of a virtual microscope up to 2π, offering super-resolution phase images. Live images of micro-organisms and neurons with resolution less than 100 nm are presented.

  20. Bubble reconstruction method for wire-mesh sensors measurements

    Science.gov (United States)

    Mukin, Roman V.

    2016-08-01

    A new algorithm is presented for post-processing of void fraction measurements with wire-mesh sensors, particularly for identifying and reconstructing bubble surfaces in a two-phase flow. This method is a combination of the bubble recognition algorithm presented in Prasser (Nuclear Eng Des 237(15):1608, 2007) and Poisson surface reconstruction algorithm developed in Kazhdan et al. (Poisson surface reconstruction. In: Proceedings of the fourth eurographics symposium on geometry processing 7, 2006). To verify the proposed technique, a comparison was done of the reconstructed individual bubble shapes with those obtained numerically in Sato and Ničeno (Int J Numer Methods Fluids 70(4):441, 2012). Using the difference between reconstructed and referenced bubble shapes, the accuracy of the proposed algorithm was estimated. At the next step, the algorithm was applied to void fraction measurements performed in Ylönen (High-resolution flow structure measurements in a rod bundle (Diss., Eidgenössische Technische Hochschule ETH Zürich, Nr. 20961, 2013) by means of wire-mesh sensors in a rod bundle geometry. The reconstructed bubble shape yields bubble surface area and volume, hence its Sauter diameter d_{32} as well. Sauter diameter is proved to be more suitable for bubbles size characterization compared to volumetric diameter d_{30}, proved capable to capture the bi-disperse bubble size distribution in the flow. The effect of a spacer grid was studied as well: For the given spacer grid and considered flow rates, bubble size frequency distribution is obtained almost at the same position for all cases, approximately at d_{32} = 3.5 mm. This finding can be related to the specific geometry of the spacer grid or the air injection device applied in the experiments, or even to more fundamental properties of the bubble breakup and coagulation processes. In addition, an application of the new algorithm for reconstruction of a large air-water interface in a tube bundle is

  1. Universal spatial correlation functions for describing and reconstructing soil microstructure.

    Science.gov (United States)

    Karsanina, Marina V; Gerke, Kirill M; Skvortsova, Elena B; Mallants, Dirk

    2015-01-01

    Structural features of porous materials such as soil define the majority of its physical properties, including water infiltration and redistribution, multi-phase flow (e.g. simultaneous water/air flow, or gas exchange between biologically active soil root zone and atmosphere) and solute transport. To characterize soil microstructure, conventional soil science uses such metrics as pore size and pore-size distributions and thin section-derived morphological indicators. However, these descriptors provide only limited amount of information about the complex arrangement of soil structure and have limited capability to reconstruct structural features or predict physical properties. We introduce three different spatial correlation functions as a comprehensive tool to characterize soil microstructure: 1) two-point probability functions, 2) linear functions, and 3) two-point cluster functions. This novel approach was tested on thin-sections (2.21×2.21 cm2) representing eight soils with different pore space configurations. The two-point probability and linear correlation functions were subsequently used as a part of simulated annealing optimization procedures to reconstruct soil structure. Comparison of original and reconstructed images was based on morphological characteristics, cluster correlation functions, total number of pores and pore-size distribution. Results showed excellent agreement for soils with isolated pores, but relatively poor correspondence for soils exhibiting dual-porosity features (i.e. superposition of pores and micro-cracks). Insufficient information content in the correlation function sets used for reconstruction may have contributed to the observed discrepancies. Improved reconstructions may be obtained by adding cluster and other correlation functions into reconstruction sets. Correlation functions and the associated stochastic reconstruction algorithms introduced here are universally applicable in soil science, such as for soil classification

  2. Reconstructing the distributed force on an atomic force microscope cantilever

    Science.gov (United States)

    Wagner, Ryan; Killgore, Jason

    2017-03-01

    A methodology is developed to reconstruct the force applied to an atomic force microscopy (AFM) cantilever given the shape in which it vibrates. This is accomplished by rewriting Bernoulli–Euler beam theory such that the force on the cantilever is approximated as a linear superposition of the theoretical cantilever eigenmodes. The weighting factors in this summation are calculated from the amplitude and phase measured along the length of the cantilever. The accuracy of the force reconstruction is shown to depend on the frequency at which the measurement is performed, the number of discrete points measured along the length of the cantilever, and the signal-to-noise ratio of the measured signal. In contrast to other AFM force reconstruction techniques, this method can reconstruct the distribution of force applied over the length of the AFM cantilever. However, this method performs poorly for localized forces applied to the cantilever, such as is typical of most tip–sample interaction forces. Proof of concept experiments are performed on an electrostatically excited cantilever and the expected force distribution is recovered. This force reconstruction technique offers previously unavailable insight into the distributed forces experienced by an AFM cantilever.

  3. Hybrid x-space: a new approach for MPI reconstruction

    Science.gov (United States)

    Tateo, A.; Iurino, A.; Settanni, G.; Andrisani, A.; Stifanelli, P. F.; Larizza, P.; Mazzia, F.; Mininni, R. M.; Tangaro, S.; Bellotti, R.

    2016-06-01

    Magnetic particle imaging (MPI) is a new medical imaging technique capable of recovering the distribution of superparamagnetic particles from their measured induced signals. In literature there are two main MPI reconstruction techniques: measurement-based (MB) and x-space (XS). The MB method is expensive because it requires a long calibration procedure as well as a reconstruction phase that can be numerically costly. On the other side, the XS method is simpler than MB but the exact knowledge of the field free point (FFP) motion is essential for its implementation. Our simulation work focuses on the implementation of a new approach for MPI reconstruction: it is called hybrid x-space (HXS), representing a combination of the previous methods. Specifically, our approach is based on XS reconstruction because it requires the knowledge of the FFP position and velocity at each time instant. The difference with respect to the original XS formulation is how the FFP velocity is computed: we estimate it from the experimental measurements of the calibration scans, typical of the MB approach. Moreover, a compressive sensing technique is applied in order to reduce the calibration time, setting a fewer number of sampling positions. Simulations highlight that HXS and XS methods give similar results. Furthermore, an appropriate use of compressive sensing is crucial for obtaining a good balance between time reduction and reconstructed image quality. Our proposal is suitable for open geometry configurations of human size devices, where incidental factors could make the currents, the fields and the FFP trajectory irregular.

  4. A new iterative algorithm to reconstruct the refractive index.

    Science.gov (United States)

    Liu, Y J; Zhu, P P; Chen, B; Wang, J Y; Yuan, Q X; Huang, W X; Shu, H; Li, E R; Liu, X S; Zhang, K; Ming, H; Wu, Z Y

    2007-06-21

    The latest developments in x-ray imaging are associated with techniques based on the phase contrast. However, the image reconstruction procedures demand significant improvements of the traditional methods, and/or new algorithms have to be introduced to take advantage of the high contrast and sensitivity of the new experimental techniques. In this letter, an improved iterative reconstruction algorithm based on the maximum likelihood expectation maximization technique is presented and discussed in order to reconstruct the distribution of the refractive index from data collected by an analyzer-based imaging setup. The technique considered probes the partial derivative of the refractive index with respect to an axis lying in the meridional plane and perpendicular to the propagation direction. Computer simulations confirm the reliability of the proposed algorithm. In addition, the comparison between an analytical reconstruction algorithm and the iterative method has been also discussed together with the convergent characteristic of this latter algorithm. Finally, we will show how the proposed algorithm may be applied to reconstruct the distribution of the refractive index of an epoxy cylinder containing small air bubbles of about 300 micro of diameter.

  5. Quantum interferences reconstruction with low homodyne detection efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, Martina; Randi, Francesco [Universita degli studi di Trieste, Dipartimento di Fisica, Trieste (Italy); Titimbo, Kelvin; Zimmermann, Klaus; Benatti, Fabio [Universita degli studi di Trieste, Dipartimento di Fisica, Trieste (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste (Italy); Kourousias, Georgios; Curri, Alessio [Sincrotrone Trieste S.C.p.A., Trieste (Italy); Floreanini, Roberto [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Trieste (Italy); Parmigiani, Fulvio [Universita degli studi di Trieste, Dipartimento di Fisica, Trieste (Italy); Sincrotrone Trieste S.C.p.A., Trieste (Italy); University of Cologne, Institute of Physics II, Cologne (Germany); Fausti, Daniele [Universita degli studi di Trieste, Dipartimento di Fisica, Trieste (Italy); Sincrotrone Trieste S.C.p.A., Trieste (Italy)

    2016-12-15

    Optical homodyne tomography consists in reconstructing the quantum state of an optical field from repeated measurements of its amplitude at different field phases (homodyne data). The experimental noise, which unavoidably affects the homodyne data, leads to a detection efficiency η<1. The problem of reconstructing quantum states from noisy homodyne data sets prompted an intense scientific debate about the presence or absence of a lower homodyne efficiency bound (η>0.5) below which quantum features, like quantum interferences, cannot be retrieved. Here, by numerical experiments, we demonstrate that quantum interferences can be effectively reconstructed also for low homodyne detection efficiency. In particular, we address the challenging case of a Schroedinger cat state and test the minimax and adaptive Wigner function reconstruction technique by processing homodyne data distributed according to the chosen state but with an efficiency η>0.5. By numerically reproducing the Schroedinger's cat interference pattern, we give evidence that quantum state reconstruction is actually possible in these conditions, and provide a guideline for handling optical tomography based on homodyne data collected by low efficiency detectors. (orig.)

  6. Surface reconstruction of W2C(0001)

    Science.gov (United States)

    Aizawa, Takashi; Hishita, Shunichi; Tanaka, Takaho; Otani, Shigeki

    2011-08-01

    A single crystal surface of ditungsten carbide, W2C(0001) was investigated using low-energy (LEED) and high-energy electron diffraction, Auger electron spectroscopy, x-ray photoelectron spectroscopy (XPS), and high-resolution electron energy loss spectroscopy (HREELS). A new reconstruction, \\sqrt {13} \\times \\sqrt {13} {R}+/- 13.9^{\\circ } , was found as a clean surface structure after annealing the W2C at > 1900 K. The surface carbon content is shown as larger than that in the bulk. Our preliminary results showed that the same structure is realized also on WC(0001). The same surface periodicity is described for an Mo2C(0001) LEED pattern in the literature. This reconstruction phase is presumably common on the (0001) surface of hexagonal group-6 transition-metal carbides. In the off-specular HREELS, an atomic vibration of 44.8 meV (361 cm - 1) appeared within the gap energy region of the bulk phonon bands, which was assigned to a surface carbon vibration perpendicular to the surface. One possible explanation of the low vibrational frequency is very low adsorption height of the surface carbon atoms.

  7. Electron track reconstruction in the ATLAS experiment

    CERN Document Server

    Tadel, Matevž; Clark, Allan

    2001-01-01

    Before entering the hardware production phase of a HEP experiment, the detector elements that have been chosen during the planning process need to be thoroughly tested. At the LHC, silicon detectors will operate in a high-rate environment which requires low-noise electronics with a shaping time of $25 s$. A prototype silicon-strip half-module equipped with the analogue read-out chip SCTA128-HC was put in a $200GeV$ pion beam. An analysis of the collected data is presented. The tested module was found to conform to the SCT-modules specification for the ATLAS experiment. Electron reconstruction in the ATLAS detector is compromised by the large amount of material in the tracking volume, which leads to frequent emissions of hard bremsstrahlung photons. This affects the measurement of the transverse projections of track parameters in the inner detector as well as the measurement of energy and azimuthal angle in the EM calorimeter for $p_T<20GeV$. Reconstruction and electron identification efficiencies are...

  8. Spectrotemporal CT data acquisition and reconstruction at low dose

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Darin P.; Badea, Cristian T., E-mail: cristian.badea@duke.edu [Department of Radiology, Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710 (United States); Lee, Chang-Lung [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Kirsch, David G. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 and Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2015-11-15

    problem using the split Bregman method and GPU-based implementations of backprojection, reprojection, and kernel regression. Using a preclinical mouse model, the authors apply the proposed algorithm to study myocardial injury following radiation treatment of breast cancer. Results: Quantitative 5D simulations are performed using the MOBY mouse phantom. Twenty data sets (ten cardiac phases, two energies) are reconstructed with 88 μm, isotropic voxels from 450 total projections acquired over a single 360° rotation. In vivo 5D myocardial injury data sets acquired in two mice injected with gold and iodine nanoparticles are also reconstructed with 20 data sets per mouse using the same acquisition parameters (dose: ∼60 mGy). For both the simulations and the in vivo data, the reconstruction quality is sufficient to perform material decomposition into gold and iodine maps to localize the extent of myocardial injury (gold accumulation) and to measure cardiac functional metrics (vascular iodine). Their 5D CT imaging protocol represents a 95% reduction in radiation dose per cardiac phase and energy and a 40-fold decrease in projection sampling time relative to their standard imaging protocol. Conclusions: Their 5D CT data acquisition and reconstruction protocol efficiently exploits the rank-sparse nature of spectral and temporal CT data to provide high-fidelity reconstruction results without increased radiation dose or sampling time.

  9. Phase microscopy of technical and biological samples through random phase modulation with a difuser

    DEFF Research Database (Denmark)

    Almoro, Percival; Pedrini, Giancarlo; Gundu, Phanindra Narayan

    2010-01-01

    A technique for phase microscopy using a phase diffuser and a reconstruction algorithm is proposed. A magnified specimen wavefront is projected on the diffuser plane that modulates the wavefront into a speckle field. The speckle patterns at axially displaced planes are sampled and used...... in an iterative phase retrieval algorithm based on a wave-propagation equation. The technique offers a whole-field and high-resolution wavefront reconstruction of unstained microstructures. Phase maps of photoresist targets and human cheek cells are obtained to demonstrate the effectiveness of our method. (C......) 2010 Optical Society of America...

  10. Phase space reconstruction using input-output time series data

    Science.gov (United States)

    Walker, David M.; Tufillaro, Nicholas B.

    1999-10-01

    In this paper we suggest that an extension of a procedure recently proposed by Wayland et al. [Phys. Rev. Lett. 70, 580 (1993)] for recognizing determinism in an autonomous time series can also be used as a diagnostic for determining an appropriate embedding dimension for driven (``input-output'') systems. We compare the results of this extension to the results produced by the extensions to the method of false nearest neighbors put forward by Rhodes and Morari [Proceedings of the American Control Conference, Seattle, edited by The American Automatic Control Council (IEEE, Piscataway, 1995)] and the method of averaged false nearest neighbors by Cao et al. [Int. J. Bifurcation Chaos 8, 1491 (1998)].

  11. Network reconstruction from infection cascades

    CERN Document Server

    Braunstein, Alfredo

    2016-01-01

    Reconstructing propagation networks from observations is a fundamental inverse problem, and it's crucial to understand and control dynamics in complex systems. Here we show that it is possible to reconstruct the whole structure of an interaction network and to simultaneously infer the complete time course of activation spreading, relying just on single snapshots of a small number of activity cascades. The method, that we called Inverse Dynamics Network Reconstruction (IDNR), is shown to work successfully on several synthetic and real networks, inferring the networks and the sources of infection based on sparse observations, including single snapshots. IDNR is built on a Belief Propagation approximation, that has an impressive performance in a wide variety of topological structures. The method can be applied in absence of complete time-series data by providing a detailed modeling of the posterior distribution of trajectories conditioned to the observations. Furthermore, we show by experiments that the informat...

  12. Track Reconstruction Performance in CMS

    CERN Document Server

    Azzurri, Paolo

    2008-01-01

    The expected performance of track reconstruction with LHC events using the CMS silicon tracker is presented. Track finding and fitting is accomplished with Kalman Filter techniques that achieve efficiencies above 99\\% on single muons with $p_T >$1~GeV/c. Difficulties arise in the context of standard LHC events with a high density of charged particles, where the rate of fake combinatorial tracks is very large for low $p_T$ tracks, and nuclear interactions in the tracker material reduce the tracking efficiency for charged hadrons. Recent improvements with the CMS track reconstruction now allow to efficiently reconstruct charged tracks with $p_T$ down to few hundred MeV/c and as few as three crossed layers, with a very small fake fraction, by making use of an optimal rejection of fake tracks in conjunction with an iterative tracking procedure.

  13. A study of image reconstruction algorithms for hybrid intensity interferometers

    Science.gov (United States)

    Crabtree, Peter N.; Murray-Krezan, Jeremy; Picard, Richard H.

    2011-09-01

    Phase retrieval is explored for image reconstruction using outputs from both a simulated intensity interferometer (II) and a hybrid system that combines the II outputs with partially resolved imagery from a traditional imaging telescope. Partially resolved imagery provides an additional constraint for the iterative phase retrieval process, as well as an improved starting point. The benefits of this additional a priori information are explored and include lower residual phase error for SNR values above 0.01, increased sensitivity, and improved image quality. Results are also presented for image reconstruction from II measurements alone, via current state-of-the-art phase retrieval techniques. These results are based on the standard hybrid input-output (HIO) algorithm, as well as a recent enhancement to HIO that optimizes step lengths in addition to step directions. The additional step length optimization yields a reduction in residual phase error, but only for SNR values greater than about 10. Image quality for all algorithms studied is quite good for SNR>=10, but it should be noted that the studied phase-recovery techniques yield useful information even for SNRs that are much lower.

  14. Clinical applications of iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Eberl, S. [Royal Prince Alfred Hospital, Camperdown, NSW (Australia). Department of PET and Nuclear Medicine

    1998-03-01

    Expectation maximisation (EM) reconstruction largely eliminates the hot and cold streaking artifacts characteristic of filtered-back projection (FBP) reconstruction around localised hot areas, such as the bladder. It also substantially reduces the problem of decreased inferior wall counts in MIBI myocardial perfusion studies due to ``streaking`` from high liver uptake. Non-uniform attenuation and scatter correction, resolution recovery, anatomical information, e.g. from MRI or CT tracer kinetic modelling, can all be built into the EM reconstruction imaging model. The properties of ordered subset EM (OSEM) have also been used to correct for known patient motion as part of the reconstruction process. These uses of EM are elaborated more fully in some of the other abstracts of this meeting. Currently we use OSEM routinely for: (i) studies where streaking is a problem, including all MIBI myocardial perfusion studies, to avoid hot liver inferior wall artifact, (ii) all whole body FDG PET, all lung V/Q SPECT (which have a short acquisition time) and all gated {sup 201}TI myocardial perfusion studies due to improved noise characteristics of OSEM in these studies; (iii) studies with measured, non-uniform attenuation correction. With the accelerated OSEM algorithm, iterative reconstruction is practical for routine clinical applications and we have found OSEM to provide clearly superior reconstructions for the areas listed above and are investigating its application to other studies. In clinical use, we have not found OSEM to introduce artifacts which would not also occur with FBP, e.g. uncorrected patient motion will cause artifacts with both OSEM and FBP.

  15. Markov Random Field Surface Reconstruction

    DEFF Research Database (Denmark)

    Paulsen, Rasmus Reinhold; Bærentzen, Jakob Andreas; Larsen, Rasmus

    2010-01-01

    ) and knowledge about data (the observation model) in an orthogonal fashion. Local models that account for both scene-specific knowledge and physical properties of the scanning device are described. Furthermore, how the optimal distance field can be computed is demonstrated using conjugate gradients, sparse......A method for implicit surface reconstruction is proposed. The novelty in this paper is the adaption of Markov Random Field regularization of a distance field. The Markov Random Field formulation allows us to integrate both knowledge about the type of surface we wish to reconstruct (the prior...

  16. Tragal reconstruction after tumor excision.

    Science.gov (United States)

    Coombs, Christopher J; Lin, Frank

    2015-02-01

    The tragus forms a distinct and important landmark in the overall artistic and anatomical landscape of the ear. Despite its small size, it functions to cover and prevent direct access to the ear canal. Aesthetically, it has an important role in defining the morphology of the auricle in 3 dimensions, not only covering the meatus but also casting a shadow into the conchal bowl that gives the impression of depth. Most of the techniques for tragal reconstruction are associated with creation of a tragus in patients with microtia. We present here a new technique for tragal reconstruction in the setting of tumor ablation.

  17. Vascular Reconstruction in Hepatic Malignancy.

    Science.gov (United States)

    Berumen, Jennifer; Hemming, Alan

    2016-04-01

    With surgery for hepatic malignancy, there are poor options for chemotherapy; many patients are deemed unresectable because of vascular involvement or location of tumors. Over the past few decades, advances in surgical technique have allowed resection of these tumors with vascular reconstruction to achieve negative margins and improve chances for survival. This article reviews those reconstruction techniques and outcomes in detail, including in situ perfusion and ex vivo liver surgery, and provides a discussion of implications and operative planning for patients with hepatic malignancy in order to provide surgeons with better understanding of these complicated operations.

  18. Rational Reconstructions of Modern Physics

    CERN Document Server

    Mittelstaedt, Peter

    2011-01-01

    Newton’s classical physics and its underlying ontology are loaded with several metaphysical hypotheses that cannot be justified by rational reasoning nor by experimental evidence. Furthermore, it is well known that some of these hypotheses are not contained in the great theories of modern physics, such as the theory of relativity and quantum mechanics. This book shows that, on the basis of Newton’s classical physics and by rational reconstruction, the theory of relativity as well as quantum mechanics can be obtained by partly eliminating or attenuating the metaphysical hypotheses. Moreover, it is shown that these reconstructions do not require additional hypotheses or new experimental results.

  19. DOLPHIn—Dictionary Learning for Phase Retrieval

    Science.gov (United States)

    Tillmann, Andreas M.; Eldar, Yonina C.; Mairal, Julien

    2016-12-01

    We propose a new algorithm to learn a dictionary for reconstructing and sparsely encoding signals from measurements without phase. Specifically, we consider the task of estimating a two-dimensional image from squared-magnitude measurements of a complex-valued linear transformation of the original image. Several recent phase retrieval algorithms exploit underlying sparsity of the unknown signal in order to improve recovery performance. In this work, we consider such a sparse signal prior in the context of phase retrieval, when the sparsifying dictionary is not known in advance. Our algorithm jointly reconstructs the unknown signal - possibly corrupted by noise - and learns a dictionary such that each patch of the estimated image can be sparsely represented. Numerical experiments demonstrate that our approach can obtain significantly better reconstructions for phase retrieval problems with noise than methods that cannot exploit such "hidden" sparsity. Moreover, on the theoretical side, we provide a convergence result for our method.

  20. Probing CP Violation with Kinematic Reconstruction at the LHC

    CERN Document Server

    Rolbiecki, K; Tattersall, J; Wienemann, P

    2010-01-01

    We discuss the potential of observing effects of CP-violation phases in squark decay chains at the LHC. As the CP-odd observable, we use the asymmetry composed by triple products of final state momenta. There are good prospects of observing these effects using the method of kinematic reconstruction for the final and intermediate state particles. We also discuss the main experimental factors and the expected sensitivity.

  1. Probing CP violation with kinematic reconstruction at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Moortgat-Pick, G.; Tattersall, J. [IPPP, Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Wienemann, P. [Department of Physics, University of Bonn, Nussallee 12, 53115 Bonn (Germany); Rolbiecki, K.

    2010-07-15

    We discuss the potential of observing effects of CP-violation phases in squark decay chains at the LHC[1]. As the CP-odd observable, we use the asymmetry composed by triple products of final state momenta. There are good prospects of observing these effects using the method of kinematic reconstruction for the final and intermediate state particles. We also discuss the main experimental factors and the expected sensitivity. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  2. GPU-based Low-dose 4DCT Reconstruction via Temporal Non-local Means

    CERN Document Server

    Tian, Zhen; Jiang, Steve B

    2010-01-01

    Four-dimensional computed tomography (4DCT) has been widely used in cancer radiotherapy for accurate target delineation and motion measurement for tumors in thorax and upper abdomen areas. However, 4DCT simulation is associated with much higher imaging dose than conventional CT simulation, which is a major concern in its clinical application. Conventionally, each phase of 4DCT is reconstructed independently using the filtered backprojection (FBP) algorithm. The basic idea of our new algorithm is that, by utilizing the common information among different phases, the input information required to reconstruct image of high quality, and thus the imaging dose, can be reduced. We proposed a temporal non-local means (TNLM) method to explore the inter-phase similarity. All phases of the 4DCT images are reconstructed simultaneously by minimizing a cost function consisting of a data fidelity term and a TNLM regularization term. We utilized a forward-backward splitting algorithm and a Gauss-Jacobi iteration method to eff...

  3. A survey of urban reconstruction

    KAUST Repository

    Musialski, Przemyslaw

    2013-05-10

    This paper provides a comprehensive overview of urban reconstruction. While there exists a considerable body of literature, this topic is still under active research. The work reviewed in this survey stems from the following three research communities: computer graphics, computer vision and photogrammetry and remote sensing. Our goal is to provide a survey that will help researchers to better position their own work in the context of existing solutions, and to help newcomers and practitioners in computer graphics to quickly gain an overview of this vast field. Further, we would like to bring the mentioned research communities to even more interdisciplinary work, since the reconstruction problem itself is by far not solved. This paper provides a comprehensive overview of urban reconstruction. While there exists a considerable body of literature, this topic is still under active research. The work reviewed in this survey stems from the following three research communities: computer graphics, computer vision and photogrammetry and remote sensing. Our goal is to provide a survey that will help researchers to better position their own work in the context of existing solutions, and to help newcomers and practitioners in computer graphics to quickly gain an overview of this vast field. Further, we would like to bring the mentioned research communities to even more interdisciplinary work, since the reconstruction problem itself is by far not solved. © 2013 The Eurographics Association and John Wiley & Sons Ltd.

  4. Reconstructing Death in Postmodern Society.

    Science.gov (United States)

    Kastenbaum, Robert

    1993-01-01

    Examines interaction between emerging thanatological movement and its sociohistorical context. Notes that thanatology will take on new shape as individuals and society attempt to cope with postmodernistic forces and deconstructive mentality. Considers prospect for authentic solidarity against distress in reconstructed death system. (Author/NB)

  5. Iterative reconstruction of digital holograms from three intensity measurements

    Science.gov (United States)

    Zhao, Liang; Wu, Yang; Kelly, Damien P.; Sheridan, John T.

    2016-03-01

    A practical technique is presented based on DH, for the reconstruction of a wavefront from three recorded intensity images. Combining the off-axis Fourier spatial filtering (OFSF) technique with iterative phase retrieval algorithms, it is shown how the twin image can be eliminated. The proposed method overcomes system geometry constraints and improves both the flexibility and resolution associated with OFSF-based DH. It also overcomes the cost problem associated with phase-shifting interferometry-based DH. In order to demonstrate the performance of the proposed DH method, both simulation and experiment results for objects having smooth and rough surfaces are presented.

  6. Cubic to tetragonal crystal lattice reconstruction during ordering or decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Byung-kl [Carnegie-Mellon Univ., Pittsburgh, PA (United States). Dept. of Materials Science and Engineering

    1992-09-01

    This thesis studied thermodynamic stability and morphology of product phases in diffusional phase transformations involving cubic-to-tetragonal crystal lattice reconstructions. Two different kinds of diffusional transformations were examined: L1{sub 0} ordering (fcc to fct lattice change) and decomposition of off-stoichiometric B2 ordering alloys accompanying bcc to fcc Bain transformation. In the first case, Fe-45 at.% Pd alloys were studied by TEM; in the second, the Bain strain relaxation during decomposition of hyper-eutectoid Cu-9.04 wt% Be alloy was studied. CuAu and InMg were also studied.

  7. On the relationship between intensity diffraction tomography and phase-contrast tomography

    Science.gov (United States)

    Anastasio, Mark A.; Shi, Daxin

    2004-10-01

    Diffraction tomography (DT) is a well-known method for reconstructing the complex-valued refractive index distribution of weakly scattering objects. A reconstruction theory of intensity DT (I-DT) has been proposed [Gbur and Wolf, JOSA A, 2002] that can accomplish such a reconstruction from knowledge of only the wavefield intensities on two different transverse planes at each tomographic view angle. In this work, we elucidate the relationship between I-DT and phase-contrast tomography and demonstrate that I-DT reconstruction theory contains some of the existing reconstruction algorithms for phase-contrast tomography as special cases.

  8. Mandibular reconstruction in adults: a review.

    NARCIS (Netherlands)

    Goh, B.T.; Lee, S.; Tideman, H.; Stoelinga, P.J.W.

    2008-01-01

    Mandibular defects may result from trauma, inflammatory disease and benign or malignant tumours. Mastication, speech and facial aesthetics are often severely compromised without reconstruction. The goal of mandibular reconstruction is to restore facial form and function, implying repair of mandibula

  9. Magni: A Python Package for Compressive Sampling and Reconstruction of Atomic Force Microscopy Images

    Directory of Open Access Journals (Sweden)

    Christian Schou Oxvig

    2014-10-01

    Full Text Available Magni is an open source Python package that embraces compressed sensing and Atomic Force Microscopy (AFM imaging techniques. It provides AFM-specific functionality for undersampling and reconstructing images from AFM equipment and thereby accelerating the acquisition of AFM images. Magni also provides researchers in compressed sensing with a selection of algorithms for reconstructing undersampled general images, and offers a consistent and rigorous way to efficiently evaluate the researchers own developed reconstruction algorithms in terms of phase transitions. The package also serves as a convenient platform for researchers in compressed sensing aiming at obtaining a high degree of reproducibility of their research.

  10. The reconstruction of diffractive object digital hologram at a short distance

    Institute of Scientific and Technical Information of China (English)

    钟丽云; 张以谟; 吕晓旭; 袁操今

    2004-01-01

    By using a spherical wave as the reference wave, we recorded the in-line phase-shifting digital hologram of the 25th element of Chinese standard No. 3 resolution test pattern, and gave the corresponding numerical reconstructed results. Some problems concerning with the digital hologram recording and reconstruction of the diffractive object at a short distance are discussed. The experimental result shows that the resolution of the reconstructed image is better than 10 μm, which is the limit by using this experimental arrangement.

  11. The reconstruction of diffractive object digital hologram at a short distance

    Institute of Scientific and Technical Information of China (English)

    Liyun Zhong(钟丽云); Yimo Zhang(张以谟); Xiaoxu L(u)(吕晓旭); Caojin Yuan(袁操今)

    2004-01-01

    By using a spherical wave as the reference wave, we recorded the in-line phase-shifting digital hologram of the 25th element of Chinese standard No. 3 resolution test pattern, and gave the corresponding numerical reconstructed results. Some problems concerning with the digital hologram recording and reconstruction of the diffractive object at a short distance are discussed. The experimental result shows that the resolution of the reconstructed image is better than 10μm, which is the limit by using this experimental arrangement.

  12. Event reconstruction performance of the ALICE High Level Trigger for p + p collisions

    CERN Document Server

    Richter, M; Alt, T; Appelshauser, H; Arend, A; Becker, B; Bottger, S; Breitner, T; Busching, H; Cicalo, C; Chattopadhyay, S; Cleymans, J; Das, I; Djuvsland, O; Erdal, H; Fearick, R; Gorbunov, S; Haaland, O S; Hille, P T; Kalcher, S; Kanaki, K; Kebschull, U; Kisel, I; Kretz, M; Lara, C; Lindal, S; Lindenstruth, V; Masoodi, A A; Ovrebekk, G; Panse, R; Peschek, J; Ploskon, M; Pocheptsov, T; Rascanu, T; Ronchetti, F; Rohr, D; Rohrich, D; Skaali, B; Steinbeck, T; Szostak, A; Thader, J; Tveter, T S; Ullaland, K; Vilakazi, Z; Weis, R; Zelnicek, P

    2011-01-01

    The ALICE High Level Trigger comprises a large computing cluster, dedicated interfaces and software applications. It allows on-line event reconstruction of the full data stream of the ALICE experiment at up to 25 GByte/s. The commissioning campaign has passed an important phase since the startup of the Large Hadron Collider in November 2009. The system has been transferred into continuous operation with focus on the event reconstruction and first simple trigger applications. The paper reports for t he first time on the achieved event reconstruction performance in the ALICE central barrel region.

  13. Effects of grinding-induced grain boundary and interfaces on electrical transportation and structure phase transition in ZnSe under high pressure

    Science.gov (United States)

    Jie, Yang; Pei, Wang; Guo-Zhao, Zhang; Xiao-Xue, Zhou; Jing, Li; Cai-Long, Liu

    2016-06-01

    Interface and scale effects are the two most important factors which strongly affect the structure and the properties of nano-/micro-crystals under pressure. We conduct an experiment under high pressure in situ alternating current impedance to elucidate the effects of interface on the structure and electrical transport behavior of two ZnSe samples with different sizes obtained by physical grinding. The results show that (i) two different-sized ZnSe samples undergo the same phase transitions from zinc blend to cinnabar-type phase and then to rock salt phase; (ii) the structural transition pressure of the 859-nm ZnSe sample is higher than that of the sample of 478 nm, which indicates the strong scale effect. The pressure induced boundary resistance change is obtained by fitting the impedance spectrum, which shows that the boundary conduction dominates the electrical transport behavior of ZnSe in the whole experimental pressure range. By comparing the impedance spectra of two different-sized ZnSe samples at high pressure, we find that the resistance of the 478-nm ZnSe sample is lower than that of the 859-nm sample, which illustrates that the sample with smaller particle size has more defects which are due to physical grinding. Project supported by the National Natural Science Foundation of China (Grant Nos. 11404133 and 11374121) and the Program of Science and Technology Development Plan of Jilin Province, China (Grant No. 20140520105JH).

  14. 3D Reconstruction Technique for Tomographic PIV

    Institute of Scientific and Technical Information of China (English)

    姜楠; 包全; 杨绍琼

    2015-01-01

    Tomographic particle image velocimetry(Tomo-PIV) is a state-of-the-art experimental technique based on a method of optical tomography to achieve the three-dimensional(3D) reconstruction for three-dimensional three-component(3D-3C) flow velocity measurements. 3D reconstruction for Tomo-PIV is carried out herein. Meanwhile, a 3D simplified tomographic reconstruction model reduced from a 3D volume light inten-sity field with 2D projection images into a 2D Tomo-slice plane with 1D projecting lines, i.e., simplifying this 3D reconstruction into a problem of 2D Tomo-slice plane reconstruction, is applied thereafter. Two kinds of the most well-known algebraic reconstruction techniques, algebraic reconstruction technique(ART) and multiple algebraic reconstruction technique(MART), are compared as well. The principles of the two reconstruction algorithms are discussed in detail, which has been performed by a series of simulation images, yielding the corresponding recon-struction images that show different features between the ART and MART algorithm, and then their advantages and disadvantages are discussed. Further discussions are made for the standard particle image reconstruction when the background noise of the pre-initial particle image has been removed. Results show that the particle image recon-struction has been greatly improved. The MART algorithm is much better than the ART. Furthermore, the computa-tional analyses of two parameters(the particle density and the number of cameras), are performed to study their effects on the reconstruction. Lastly, the 3D volume particle field is reconstructed by using the improved algorithm based on the simplified 3D tomographic reconstruction model, which proves that the algorithm simplification is feasible and it can be applied to the reconstruction of 3D volume particle field in a Tomo-PIV system.

  15. Top reconstruction and boosted top experimental overview

    CERN Document Server

    Skinnari, Louise

    2015-01-01

    An overview of techniques used to reconstruct resolved and boosted top quarks is presented. Techniques for resolved top quark reconstruction include kinematic likelihood fitters and pseudo- top reconstruction. Many tools and methods are available for the reconstruction of boosted top quarks, such as jet grooming techniques, jet substructure variables, and dedicated top taggers. Different techniques as used by ATLAS and CMS analyses are described and the performance of different variables and top taggers are shown.

  16. Thermographic image reconstruction using ultrasound reconstruction from virtual waves

    CERN Document Server

    Burgholzer, Peter; Gruber, Jürgen; Mayr, Günther

    2016-01-01

    Reconstruction of subsurface features from ultrasound signals measured on the surface is widely used in medicine and non-destructive testing. In this work, we introduce a concept how to use image reconstruction methods known from ultrasonic imaging for thermographic signals, i.e. on the measured temperature evolution on a sample surface. Before using these imaging methods a virtual signal is calculated by applying a transformation to the measured temperature evolution. The virtual signal is calculated locally for every detection point and has the same initial temperature distribution as the measured signal, but is a solution of the wave equation. The introduced transformation can be used for every shape of the detection surface and in every dimension. It describes all the irreversibility of the heat diffusion, which is responsible that the spatial resolution gets worse with increasing depth. Up to now, for thermographic imaging mostly one-dimensional methods, e.g., for depth-profiling were used, which are sui...

  17. Effects of ACL Reconstructive Surgery on Temporal Variations of Cytokine Levels in Synovial Fluid

    Directory of Open Access Journals (Sweden)

    Marco Bigoni

    2016-01-01

    Full Text Available Anterior cruciate ligament (ACL reconstruction restores knee stability but does not reduce the incidence of posttraumatic osteoarthritis induced by inflammatory cytokines. The aim of this research was to longitudinally measure IL-1β, IL-6, IL-8, IL-10, and TNF-α levels in patients subjected to ACL reconstruction using bone-patellar tendon-bone graft. Synovial fluid was collected within 24–72 hours of ACL rupture (acute, 1 month after injury immediately prior to surgery (presurgery, and 1 month thereafter (postsurgery. For comparison, a “control” group consisted of individuals presenting chronic ACL tears. Our results indicate that levels of IL-6, IL-8, and IL-10 vary significantly over time in reconstruction patients. In the acute phase, the levels of these cytokines in reconstruction patients were significantly greater than those in controls. In the presurgery phase, cytokine levels in reconstruction patients were reduced and comparable with those in controls. Finally, cytokine levels increased again with respect to control group in the postsurgery phase. The levels of IL-1β and TNF-α showed no temporal variation. Our data show that the history of an ACL injury, including trauma and reconstruction, has a significant impact on levels of IL-6, IL-8, and IL-10 in synovial fluid but does not affect levels of TNF-α and IL-1β.

  18. Improved wavefront reconstruction algorithm from slope measurements

    Science.gov (United States)

    Phuc, Phan Huy; Manh, Nguyen The; Rhee, Hyug-Gyo; Ghim, Young-Sik; Yang, Ho-Soon; Lee, Yun-Woo

    2017-03-01

    In this paper, we propose a wavefront reconstruction algorithm from slope measurements based on a zonal method. In this algorithm, the slope measurement sampling geometry used is the Southwell geometry, in which the phase values and the slope data are measured at the same nodes. The proposed algorithm estimates the phase value at a node point using the slope measurements of eight points around the node, as doing so is believed to result in better accuracy with regard to the wavefront. For optimization of the processing time, a successive over-relaxation method is applied to iteration loops. We use a trial-and-error method to determine the best relaxation factor for each type of wavefront in order to optimize the iteration time and, thus, the processing time of the algorithm. Specifically, for a circularly symmetric wavefront, the convergence rate of the algorithm can be improved by using the result of a Fourier Transform as an initial value for the iteration. Various simulations are presented to demonstrate the improvements realized when using the proposed algorithm. Several experimental measurements of deflectometry are also processed by using the proposed algorithm.

  19. Three-dimensional Finite Element Analysis and Biomechanical Study on Reconstruction of the Large Defect of Proximal Femur with Allograft Prosthesis Composite in Clinical Bone-Healing Phase%复合移植重建股骨近段大段骨缺损骨临床愈合期的三维有限元分析

    Institute of Scientific and Technical Information of China (English)

    行斌斌; 段宏; 屠重棋; 陈和仲; 罗教明

    2009-01-01

    Three-dimensional finite element models of the large defect of proximal femur were reconstructed with allograft prosthesis composite in clinical bone-healing phase;current model was under the given conditions of 138mm-intramedullary stem-length of host bone and 135mm defect-length of proximal femur. The femur was constructed with efilm software from CT data,then three-dimensional concrete models were created by using Proe-Wildfire software;the three-dimensional finite element models of allograft prosthesis composite were made in ANSYS11 software. Loads were simulated using the peaking values during stance walking. The stress on femur-cement-callus-prostheses and the influence of stress on the clinical bone-healing phase were analysed.The highest stress value of femur is on the medial side of the tip of the prostheses. The highest stress value of cement mantle is on the medical side of the cement mantle at the tip of the stem. The highest stress value of the prostheses is on the medial side near the upper 4cm of the stem tip. The highest stress value on the callus is at the medial side of the callus layer. The highest stress value on every part is under the corresponding fatigue strength. Clinical bone-healing phase model is well enough for stance walking.%建立同种异体骨与人工关节复合移植重建股骨近段大段骨缺损骨临床愈合期的三维有限元模型,设定股骨近段骨缺损长度为135 mm,假体柄植入宿主股骨髓腔内长度为138 mm,首先采用efilm软件对股骨CT扫描图像进行三维重建,将重建数据及测量的假体参数导入ProeWildfire3.0软件建立三维实体模型,而后在ANSYS11.0中建立三维有限元模型,以下肢稳态步行的峰值负荷生理加载,得出载荷对股骨、骨痂、骨水泥及假体应力分布的影响.股骨应力值在假体柄尖端内侧处达到最大值,骨水泥壳应力最大值位于假体柄尖端骨水泥壳内侧,假体应力最大值位于假体柄尖端近端4

  20. Vertex Reconstruction in ATLAS Run II

    CERN Document Server

    Zhang, Matt; The ATLAS collaboration

    2016-01-01

    Vertex reconstruction is the process of taking reconstructed tracks and using them to determine the locations of proton collisions. In this poster we present the performance of our current vertex reconstruction algorithm, and look at investigations into potential improvements from a new seed finding method.

  1. In-line phase shift tomosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Hammonds, Jeffrey C.; Price, Ronald R.; Pickens, David R.; Donnelly, Edwin F. [Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232 (United States)

    2013-08-15

    Purpose: The purpose of this work is to (1) demonstrate laboratory measurements of phase shift images derived from in-line phase-contrast radiographs using the attenuation-partition based algorithm (APBA) of Yan et al.[Opt. Express 18(15), 16074–16089 (2010)], (2) verify that the APBA reconstructed images obey the linearity principle, and (3) reconstruct tomosynthesis phase shift images from a collection of angularly sampled planar phase shift images.Methods: An unmodified, commercially available cabinet x-ray system (Faxitron LX-60) was used in this experiment. This system contains a tungsten anode x-ray tube with a nominal focal spot size of 10 μm. The digital detector uses CsI/CMOS with a pixel size of 50 × 50 μm. The phantoms used consisted of one acrylic plate, two polystyrene plates, and a habanero pepper. Tomosynthesis images were reconstructed from 51 images acquired over a ±25° arc. All phase shift images were reconstructed using the APBA.Results: Image contrast derived from the planar phase shift image of an acrylic plate of uniform thickness exceeded the contrast of the traditional attenuation image by an approximate factor of two. Comparison of the planar phase shift images from a single, uniform thickness polystyrene plate with two polystyrene plates demonstrated an approximate linearity of the estimated phase shift with plate thickness (−1600 rad vs −2970 rad). Tomographic phase shift images of the habanero pepper exhibited acceptable spatial resolution and contrast comparable to the corresponding attenuation image.Conclusions: This work demonstrated the feasibility of laboratory-based phase shift tomosynthesis and suggests that phase shift imaging could potentially provide a new imaging biomarker. Further investigation will be needed to determine if phase shift contrast will be able to provide new tissue contrast information or improved clinical performance.

  2. Quantitative image quality evaluation for cardiac CT reconstructions

    Science.gov (United States)

    Tseng, Hsin-Wu; Fan, Jiahua; Kupinski, Matthew A.; Balhorn, William; Okerlund, Darin R.

    2016-03-01

    Maintaining image quality in the presence of motion is always desirable and challenging in clinical Cardiac CT imaging. Different image-reconstruction algorithms are available on current commercial CT systems that attempt to achieve this goal. It is widely accepted that image-quality assessment should be task-based and involve specific tasks, observers, and associated figures of merits. In this work, we developed an observer model that performed the task of estimating the percentage of plaque in a vessel from CT images. We compared task performance of Cardiac CT image data reconstructed using a conventional FBP reconstruction algorithm and the SnapShot Freeze (SSF) algorithm, each at default and optimal reconstruction cardiac phases. The purpose of this work is to design an approach for quantitative image-quality evaluation of temporal resolution for Cardiac CT systems. To simulate heart motion, a moving coronary type phantom synchronized with an ECG signal was used. Three different percentage plaques embedded in a 3 mm vessel phantom were imaged multiple times under motion free, 60 bpm, and 80 bpm heart rates. Static (motion free) images of this phantom were taken as reference images for image template generation. Independent ROIs from the 60 bpm and 80 bpm images were generated by vessel tracking. The observer performed estimation tasks using these ROIs. Ensemble mean square error (EMSE) was used as the figure of merit. Results suggest that the quality of SSF images is superior to the quality of FBP images in higher heart-rate scans.

  3. Fast phylogeny reconstruction through learning of ancestral sequences

    CERN Document Server

    Mihaescu, Radu; Rao, Satish

    2008-01-01

    Given natural limitations on the length DNA sequences, designing phylogenetic reconstruction methods which are reliable under limited information is a crucial endeavor. There have been two approaches to this problem: reconstructing partial but reliable information about the tree (\\cite{Mo07, DMR08,DHJ06,GMS08}), and reaching "deeper" in the tree through reconstruction of ancestral sequences. In the latter category, \\cite{DMR06} settled an important conjecture of M.Steel, showing that, under the CFN model of evolution, all trees on $n$ leaves with edge lengths bounded by the Ising model phase transition can be recovered with high probability from genomes of length $O(\\log n)$ with a polynomial time algorithm. Their methods had a running time of $O(n^{10})$. Here we enhance our methods from \\cite{DHJ06} with the learning of ancestral sequences and provide an algorithm for reconstructing a sub-forest of the tree which is reliable given available data, without requiring a-priori known bounds on the edge lengths o...

  4. Model Based Iterative Reconstruction for Bright Field Electron Tomography (Postprint)

    Science.gov (United States)

    2013-02-01

    Reconstruction Technique ( SIRT ) are applied to the data. Model based iterative reconstruction (MBIR) provides a powerful framework for tomographic...the reconstruction when the typical algorithms such as Filtered Back Projection (FBP) and Simultaneous Iterative Reconstruction Technique ( SIRT ) are

  5. Network reconstruction via density sampling

    CERN Document Server

    Squartini, Tiziano; Gabrielli, Andrea; Garlaschelli, Diego

    2016-01-01

    Reconstructing weighted networks from partial information is necessary in many important circumstances, e.g. for a correct estimation of systemic risk. It has been shown that, in order to achieve an accurate reconstruction, it is crucial to reliably replicate the empirical degree sequence, which is however unknown in many realistic situations. More recently, it has been found that the knowledge of the degree sequence can be replaced by the knowledge of the strength sequence, which is typically accessible, complemented by that of the total number of links, thus considerably relaxing the observational requirements. Here we further relax these requirements and devise a procedure valid when even the the total number of links is unavailable. We assume that, apart from the heterogeneity induced by the degree sequence itself, the network is homogeneous, so that its link density can be estimated by sampling subsets of nodes with representative density. We show that the best way of sampling nodes is the random selecti...

  6. Blind reconstruction of linear scrambler

    Institute of Scientific and Technical Information of China (English)

    Hui Xie; Fenghua Wang; Zhitao Huang

    2014-01-01

    An algorithm based on eigenanalysis technique and Walsh-Hadamard transform (WHT) is proposed. The algorithm contains two steps. Firstly, the received sequence is divided into temporal windows, and a covariance matrix is computed. The li-near feedback shift register (LFSR) sequence is reconstructed from the first eigenvector of this matrix. Secondly, equations ac-cording to the recovered LFSR sequence are constructed, and the Walsh spectrum corresponding to the equations is computed. The feedback polynomial of LFSR is estimated from the Walsh spec-trum. The validity of the algorithm is verified by the simulation result. Final y, case studies are presented to il ustrate the perfor-mance of the blind reconstruction method.

  7. Bayes reconstruction of missing teeth

    DEFF Research Database (Denmark)

    Sporring, Jon; Jensen, Katrine Hommelhoff

    2008-01-01

     We propose a method for restoring the surface of tooth crowns in a 3D model of a human denture, so that the pose and anatomical features of the tooth will work well for chewing. This is achieved by including information about the position and anatomy of the other teeth in the mouth. Our system...... contains two major parts: A statistical model of a selection of tooth shapes and a reconstruction of missing data. We use a training set consisting of 3D scans of dental cast models obtained with a laser scanner, and we have build a model of the shape variability of the teeth, their neighbors...... regularization of the log-likelihood estimate based on differential geometrical properties of teeth surfaces, and we show general conditions under which this may be considered a Bayes prior.Finally we use Bayes method to propose the reconstruction of missing data, for e.g. finding the most probable shape...

  8. Reconstruction of complete interval tournaments

    CERN Document Server

    Iványi, Antal

    2010-01-01

    Let $a, b$ and $n$ be nonnegative integers $(b \\geq a, \\ b > 0, \\ n \\geq 1)$, $\\mathcal{G}_n(a,b)$ be a multigraph on $n$ vertices in which any pair of vertices is connected with at least $a$ and at most $b$ edges and \\textbf{v =} $(v_1, v_2, ..., v_n)$ be a vector containing $n$ nonnegative integers. We give a necessary and sufficient condition for the existence of such orientation of the edges of $\\mathcal{G}_n(a,b)$, that the resulted out-degree vector equals to \\textbf{v}. We describe a reconstruction algorithm. In worst case checking of \\textbf{v} requires $\\Theta(n)$ time and the reconstruction algorithm works in $O(bn^3)$ time. Theorems of H. G. Landau (1953) and J. W. Moon (1963) on the score sequences of tournaments are special cases $b = a = 1$ resp. $b = a \\geq 1$ of our result.

  9. X-Ray Tomographic Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Bonnie Schmittberger

    2010-08-25

    Tomographic scans have revolutionized imaging techniques used in medical and biological research by resolving individual sample slices instead of several superimposed images that are obtained from regular x-ray scans. X-Ray fluorescence computed tomography, a more specific tomography technique, bombards the sample with synchrotron x-rays and detects the fluorescent photons emitted from the sample. However, since x-rays are attenuated as they pass through the sample, tomographic scans often produce images with erroneous low densities in areas where the x-rays have already passed through most of the sample. To correct for this and correctly reconstruct the data in order to obtain the most accurate images, a program employing iterative methods based on the inverse Radon transform was written. Applying this reconstruction method to a tomographic image recovered some of the lost densities, providing a more accurate image from which element concentrations and internal structure can be determined.

  10. STUDY ON PHASE PERCEPTION IN SPEECH

    Institute of Scientific and Technical Information of China (English)

    Tong Ming; Bian Zhengzhong; Li Xiaohui; Dai Qijun; Chen Yanpu

    2003-01-01

    The perceptual effect of the phase information in speech has been studied by auditorysubjective tests. On the condition that the phase spectrum in speech is changed while amplitudespectrum is unchanged, the tests show that: (1) If the envelop of the reconstructed speech signalis unchanged, there is indistinctive auditory perception between the original speech and thereconstructed speech; (2) The auditory perception effect of the reconstructed speech mainly lieson the amplitude of the derivative of the additive phase; (3) td is the maximum relative time shiftbetween different frequency components of the reconstructed speech signal. The speech qualityis excellent while td <10ms; good while 10ms< td <20ms; common while 20ms< td <35ms, andpoor while td >35ms.

  11. Two-step phase-shifting SPIDER

    Science.gov (United States)

    Zheng, Shuiqin; Cai, Yi; Pan, Xinjian; Zeng, Xuanke; Li, Jingzhen; Li, Ying; Zhu, Tianlong; Lin, Qinggang; Xu, Shixiang

    2016-01-01

    Comprehensive characterization of ultrafast optical field is critical for ultrashort pulse generation and its application. This paper combines two-step phase-shifting (TSPS) into the spectral phase interferometry for direct electric-field reconstruction (SPIDER) to improve the reconstruction of ultrafast optical-fields. This novel SPIDER can remove experimentally the dc portion occurring in traditional SPIDER method by recording two spectral interferograms with π phase-shifting. As a result, the reconstructed results are much less disturbed by the time delay between the test pulse replicas and the temporal widths of the filter window, thus more reliable. What is more, this SPIDER can work efficiently even the time delay is so small or the measured bandwidth is so narrow that strong overlap happens between the dc and ac portions, which allows it to be able to characterize the test pulses with complicated temporal/spectral structures or narrow bandwidths. PMID:27666528

  12. Modern methods of image reconstruction.

    Science.gov (United States)

    Puetter, R. C.

    The author reviews the image restoration or reconstruction problem in its general setting. He first discusses linear methods for solving the problem of image deconvolution, i.e. the case in which the data are a convolution of a point-spread function and an underlying unblurred image. Next, non-linear methods are introduced in the context of Bayesian estimation, including maximum likelihood and maximum entropy methods. Then, the author discusses the role of language and information theory concepts for data compression and solving the inverse problem. The concept of algorithmic information content (AIC) is introduced and is shown to be crucial to achieving optimal data compression and optimized Bayesian priors for image reconstruction. The dependence of the AIC on the selection of language then suggests how efficient coordinate systems for the inverse problem may be selected. The author also introduced pixon-based image restoration and reconstruction methods. The relation between image AIC and the Bayesian incarnation of Occam's Razor is discussed, as well as the relation of multiresolution pixon languages and image fractal dimension. Also discussed is the relation of pixons to the role played by the Heisenberg uncertainty principle in statistical physics and how pixon-based image reconstruction provides a natural extension to the Akaike information criterion for maximum likelihood. The author presents practical applications of pixon-based Bayesian estimation to the restoration of astronomical images. He discusses the effects of noise, effects of finite sampling on resolution, and special problems associated with spatially correlated noise introduced by mosaicing. Comparisons to other methods demonstrate the significant improvements afforded by pixon-based methods and illustrate the science that such performance improvements allow.

  13. Bayes reconstruction of missing teeth

    DEFF Research Database (Denmark)

    Sporring, Jon; Jensen, Katrine Hommelhoff

    2008-01-01

     We propose a method for restoring the surface of tooth crowns in a 3D model of a human denture, so that the pose and anatomical features of the tooth will work well for chewing. This is achieved by including information about the position and anatomy of the other teeth in the mouth. Our system...... of a missing tooth based on the best match with our shape model on the known data, and we superior improved reconstructions of our full system....

  14. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1992-02-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demography, food consumption, and agriculture; environmental pathways and dose estimates.

  15. Tomographic reconstruction of high energy density plasmas with picosecond temporal resolution

    Energy Technology Data Exchange (ETDEWEB)

    Baker, K L

    2005-09-20

    Three-dimensional reconstruction of the electron density in a plasma can be obtained by passing multiple beams at different field angles simultaneously through a plasma and performing a tomographic reconstruction of the measured field-dependent phase profiles. In this letter, a relatively simple experimental setup is proposed and simulations are carried out to verify the technique. The plasma distribution is modeled as a discreet number of phase screens and a Zernike polynomial representation of the phase screens is used to reconstruct the plasma profile. Using a subpicosecond laser, the complete three-dimensional electron density of the plasma can be obtained with a time resolution limited only by the transit time of the probe through the plasma.

  16. Reconstructing propagation networks with temporal similarity metrics

    CERN Document Server

    Liao, Hao

    2014-01-01

    Node similarity is a significant property driving the growth of real networks. In this paper, based on the observed spreading results we apply the node similarity metrics to reconstruct propagation networks. We find that the reconstruction accuracy of the similarity metrics is strongly influenced by the infection rate of the spreading process. Moreover, there is a range of infection rate in which the reconstruction accuracy of some similarity metrics drops to nearly zero. In order to improve the similarity-based reconstruction method, we finally propose a temporal similarity metric to take into account the time information of the spreading. The reconstruction results are remarkably improved with the new method.

  17. A Reduction of the Graph Reconstruction Conjecture

    Directory of Open Access Journals (Sweden)

    Monikandan S.

    2014-08-01

    Full Text Available A graph is said to be reconstructible if it is determined up to isomor- phism from the collection of all its one-vertex deleted unlabeled subgraphs. Reconstruction Conjecture (RC asserts that all graphs on at least three vertices are reconstructible. In this paper, we prove that interval-regular graphs and some new classes of graphs are reconstructible and show that RC is true if and only if all non-geodetic and non-interval-regular blocks G with diam(G = 2 or diam(Ḡ = diam(G = 3 are reconstructible

  18. Reconstruction of topology and geometry from digitisations

    DEFF Research Database (Denmark)

    2016-01-01

    . The first problem, the reconstruction of topology in dimension three, is approached using combinatorics of voxel reconstructions in combination with differential topology results. An improved digital re-construction based on binary images of objects with sufficiently smooth boundary is proposed. It is shown...... that this reconstruction is ambient isotopic to the underlying object provided the resolution of the digitisation be sufficiently high and under certain assumptions on the classical voxel reconstruction. The exact lower bound on the resolution, related to the curvature of the boundary of the object, is given...

  19. Network reconstruction via graph blending

    Science.gov (United States)

    Estrada, Rolando

    2016-05-01

    Graphs estimated from empirical data are often noisy and incomplete due to the difficulty of faithfully observing all the components (nodes and edges) of the true graph. This problem is particularly acute for large networks where the number of components may far exceed available surveillance capabilities. Errors in the observed graph can render subsequent analyses invalid, so it is vital to develop robust methods that can minimize these observational errors. Errors in the observed graph may include missing and spurious components, as well fused (multiple nodes are merged into one) and split (a single node is misinterpreted as many) nodes. Traditional graph reconstruction methods are only able to identify missing or spurious components (primarily edges, and to a lesser degree nodes), so we developed a novel graph blending framework that allows us to cast the full estimation problem as a simple edge addition/deletion problem. Armed with this framework, we systematically investigate the viability of various topological graph features, such as the degree distribution or the clustering coefficients, and existing graph reconstruction methods for tackling the full estimation problem. Our experimental results suggest that incorporating any topological feature as a source of information actually hinders reconstruction accuracy. We provide a theoretical analysis of this phenomenon and suggest several avenues for improving this estimation problem.

  20. Femoral Reconstruction Using External Fixation

    Directory of Open Access Journals (Sweden)

    Yevgeniy Palatnik

    2011-01-01

    Full Text Available Background. The use of an external fixator for the purpose of distraction osteogenesis has been applied to a wide range of orthopedic problems caused by such diverse etiologies as congenital disease, metabolic conditions, infections, traumatic injuries, and congenital short stature. The purpose of this study was to analyze our experience of utilizing this method in patients undergoing a variety of orthopedic procedures of the femur. Methods. We retrospectively reviewed our experience of using external fixation for femoral reconstruction. Three subgroups were defined based on the primary reconstruction goal lengthening, deformity correction, and repair of nonunion/bone defect. Factors such as leg length discrepancy (LLD, limb alignment, and external fixation time and complications were evaluated for the entire group and the 3 subgroups. Results. There was substantial improvement in the overall LLD, femoral length discrepancy, and limb alignment as measured by mechanical axis deviation (MAD and lateral distal femoral angle (LDFA for the entire group as well as the subgroups. Conclusions. The Ilizarov external fixator allows for decreased surgical exposure and preservation of blood supply to bone, avoidance of bone grafting and internal fixation, and simultaneous lengthening and deformity correction, making it a very useful technique for femoral reconstruction.

  1. Photogrammetric Reconstruction with Bayesian Information

    Science.gov (United States)

    Masiero, A.; Fissore, F.; Guarnieri, A.; Pirotti, F.; Vettore, A.

    2016-06-01

    Nowadays photogrammetry and laser scanning methods are the most wide spread surveying techniques. Laser scanning methods usually allow to obtain more accurate results with respect to photogrammetry, but their use have some issues, e.g. related to the high cost of the instrumentation and the typical need of high qualified personnel to acquire experimental data on the field. Differently, photogrammetric reconstruction can be achieved by means of low cost devices and by persons without specific training. Furthermore, the recent diffusion of smart devices (e.g. smartphones) embedded with imaging and positioning sensors (i.e. standard camera, GNSS receiver, inertial measurement unit) is opening the possibility of integrating more information in the photogrammetric reconstruction procedure, in order to increase its computational efficiency, its robustness and accuracy. In accordance with the above observations, this paper examines and validates new possibilities for the integration of information provided by the inertial measurement unit (IMU) into the photogrammetric reconstruction procedure, and, to be more specific, into the procedure for solving the feature matching and the bundle adjustment problems.

  2. Reconciling reconstructed and simulated features of the winter Pacific–North-American pattern in the early 19th century

    Directory of Open Access Journals (Sweden)

    D. Zanchettin

    2014-11-01

    Full Text Available Reconstructions of past climate behavior often describe prominent anomalous periods that are not necessarily captured in climate simulations. Here, we illustrate the contrast between an interdecadal strong positive phase of the winter Pacific/North American pattern (PNA in the early 19th century that is described by a PNA reconstruction based on tree-rings from northwestern North America, and a slight tendency towards negative winter PNA anomalies during the same period in an ensemble of state-of-the-art coupled climate simulations. Additionally, a pseudo-proxy investigation with the same simulation ensemble allows assessing the robustness of PNA reconstructions using solely geophysical predictors from northwestern North America for the last millennium. The reconstructed early-19th-century positive PNA anomaly emerges as a potentially reliable feature, although it is subject to a number of sources of uncertainty and potential deficiencies. The pseudo-reconstructions demonstrate that the early-19th-century discrepancy between reconstructed and simulated PNA does not stem from the reconstruction process. Instead, reconstructed and simulated features of the early-19th-century PNA can be reconciled by interpreting the reconstructed evolution during this time as an expression of internal climate variability, hence unlikely to be reproduced in its exact temporal occurrence by a small ensemble of climate simulations. However, firm attribution of the reconstructed PNA anomaly is hampered by known limitations and deficiencies of coupled climate models and uncertainties in the early-19th-century external forcing and background climate conditions.

  3. Mandibular Reconstruction, State of the Art

    Directory of Open Access Journals (Sweden)

    Julio ACERO

    2011-08-01

    Full Text Available SUMMARY: Mandibular bone loss can result in severe aesthetic and functional consequences for the patient, posing a challenge to the reconstructive maxillo-facial surgeon. Advent of microvascular surgery revolutionized mandible reconstruction introducing the possibility to transfer vascularized bone and soft tissues with high success rate. Major donor sites are the fibula, iliac crest and scapula. Planning of the reconstruction and advantages and disadvantages of the different reconstructive methods are discussed. The iliac crest provides an excellent bone for mandibular reconstruction but has some limits concerning length and versatility of soft tissues. The fibula permits the repair of large mandibular defects due to its length while the scapular osteocutaneous flap allows for the reconstruction of limited bone defects associated with large soft tissue defects. Nonvascularized reconstructive methods are associated with higher failure rates but can be considered in selected cases.

  4. Image artefact propagation in motion estimation and reconstruction in interventional cardiac C-arm CT.

    Science.gov (United States)

    Müller, K; Maier, A K; Schwemmer, C; Lauritsch, G; De Buck, S; Wielandts, J-Y; Hornegger, J; Fahrig, R

    2014-06-21

    The acquisition of data for cardiac imaging using a C-arm computed tomography system requires several seconds and multiple heartbeats. Hence, incorporation of motion correction in the reconstruction step may improve the resulting image quality. Cardiac motion can be estimated by deformable three-dimensional (3D)/3D registration performed on initial 3D images of different heart phases. This motion information can be used for a motion-compensated reconstruction allowing the use of all acquired data for image reconstruction. However, the result of the registration procedure and hence the estimated deformations are influenced by the quality of the initial 3D images. In this paper, the sensitivity of the 3D/3D registration step to the image quality of the initial images is studied. Different reconstruction algorithms are evaluated for a recently proposed cardiac C-arm CT acquisition protocol. The initial 3D images are all based on retrospective electrocardiogram (ECG)-gated data. ECG-gating of data from a single C-arm rotation provides only a few projections per heart phase for image reconstruction. This view sparsity leads to prominent streak artefacts and a poor signal to noise ratio. Five different initial image reconstructions are evaluated: (1) cone beam filtered-backprojection (FDK), (2) cone beam filtered-backprojection and an additional bilateral filter (FFDK), (3) removal of the shadow of dense objects (catheter, pacing electrode, etc) before reconstruction with a cone beam filtered-backprojection (cathFDK), (4) removal of the shadow of dense objects before reconstruction with a cone beam filtered-backprojection and a bilateral filter (cathFFDK). The last method (5) is an iterative few-view reconstruction (FV), the prior image constrained compressed sensing combined with the improved total variation algorithm. All reconstructions are investigated with respect to the final motion-compensated reconstruction quality. The algorithms were tested on a mathematical

  5. Improvement of tomographic reconstruction in bone SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Schuenemann, M.; Sahlmann, C.O.; Siefker, U.; Luig, H.; Meller, J. [Abteilungen fuer Nuklearmedizin, Georg-August-Univ. Goettingen (Germany); Heidrich, G. [Abteilungen fuer Diagnostische Radiologie, Georg-August-Univ., Goettingen (Germany); Werner, C.; Brunner, E. [Abteilungen fuer Medizinische Statistik, Georg-August-Univ., Goettingen (Germany)

    2006-07-01

    Aim: the comparison between iterative reconstruction and filtered backprojection in the reconstruction of bone SPECT in the diagnosis of skeletal metastases. Patients, methods: 47 consecutive patients (vertebral segments: n = 435), with suspected malignancy of the vertebral column, were examined by bone scintigraphy and MRI (maximal interval between the two procedures {+-} 5 weeks). The SPECT-data were reconstructed with an iterative algorithm (ISA) and with filtered backprojection. We defined semiquantitative criteria in order to assess the quality of the tomograms. Conventional reconstruction was performed both by a Wiener-filter and a low-pass-filter. Iterative reconstruction was performed by the ISA algorithm. The clinical evaluation of the different reconstruction algorithms was performed by MRI as the gold-standard. Results: sensitivity (%): 87.3 (ISA), 86.4 (low-pass), 79.7 (Wiener); specificity (%): 95.3 (ISA), 95 (low-pass), 85.4 (Wiener). The sensitivity of iterative reconstructed SPECT and low-pass reconstructed SPECT was significantly higher (p < 0.05) compared with the sensitivity of SPECT reconstructed by the Wiener-filter. The specificity of iterative reconstruction ISA and low-pass-filter reconstructed SPECT were significantly higher compared with the SPECT data reconstructed by the Wiener-filter. ISA was significantly superior to the Wiener-SPECT relating to all criteria of quality. Iterative reconstruction was significantly superior to the low-pass-SPECT relating to 2 of 3 criteria. In addition the Wiener-SPECT was significantly inferior to the low-pass-SPECT regarding to 2 of 3 criteria. Conclusion: in our series the iterative algorithm ISA was the method of choice in the reconstruction of bone SPECT data. In comparison with conventional algorithms ISA offers a significantly higher quality of the tomograms and yields a high diagnostic accuracy. (orig.)

  6. Phase Aberrations in Diffraction Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Marchesini, S; Chapman, H N; Barty, A; Howells, M R; Spence, J H; Cui, C; Weierstall, U; Minor, A M

    2005-09-29

    In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a lens the resolution is limited, in principle, only by the largest scattering angles recorded. However, the imaging task is shifted from the experiment to the computer, and the algorithm's ability to recover meaningful images in the presence of noise and limited prior knowledge may produce aberrations in the reconstructed image. We analyze the low order aberrations produced by our phase retrieval algorithms. We present two methods to improve the accuracy and stability of reconstructions.

  7. Improvement of the image quality of random phase--free holography using an iterative method

    CERN Document Server

    Shimobaba, Tomoyoshi; Endo, Yutaka; Hirayama, Ryuji; Hiyama, Daisuke; Hasegawa, Satoki; Nagahama, Yuki; Sano, Marie; Oikawa, Minoru; Sugie, Takashige; Ito, Tomoyoshi

    2015-01-01

    Our proposed method of random phase-free holography using virtual convergence light can obtain large reconstructed images exceeding the size of the hologram, without the assistance of random phase. The reconstructed images have low-speckle noise in the amplitude and phase-only holograms (kinoforms); however, in low-resolution holograms, we obtain a degraded image quality compared to the original image. We propose an iterative random phase-free method with virtual convergence light to address this problem.

  8. Reconstruction of the joint state of a two-mode Bose-Einstein condensate

    CERN Document Server

    Bolda, E L; Walls, D F; Bolda, Eric L.; Tan, Sze M.; Walls, Dan F.

    1997-01-01

    We propose a scheme to reconstruct the state of a two-mode Bose-Einstein condensate, with a given total number of atoms, using an atom interferometer that requires beam splitter, phase shift and non-ideal atom counting operations. The density matrix in the number-state basis can be computed directly from the probabilities of different counts for various phase shifts between the original modes, unless the beamsplitter is exactly balanced. Simulated noisy data from a two-mode coherent state is produced and the state is reconstructed, for 49 atoms. The error can be estimated from the singular values of the transformation matrix between state and probability data.

  9. Reconstruction of spectral solar irradiance since 1700 from simulated magnetograms

    CERN Document Server

    Dasi-Espuig, M; Krivova, N A; Solanki, S K; Unruh, Y C; Yeo, K L

    2016-01-01

    We present a reconstruction of the spectral solar irradiance since 1700 using the SATIRE-T2 (Spectral And Total Irradiance REconstructions for the Telescope era version 2) model. This model uses as input magnetograms simulated with a surface flux transport model fed with semi-synthetic records of emerging sunspot groups. We used statistical relationships between the properties of sunspot group emergence, such as the latitude, area, and tilt angle, and the sunspot cycle strength and phase to produce semi-synthetic sunspot group records starting in the year 1700. The semisynthetic records are fed into a surface flux transport model to obtain daily simulated magnetograms that map the distribution of the magnetic flux in active regions (sunspots and faculae) and their decay products on the solar surface. The magnetic flux emerging in ephemeral regions is accounted for separately based on the concept of extended cycles whose length and amplitude are linked to those of the sunspot cycles through the sunspot number....

  10. 3 dimensional ionospheric electron density reconstruction based on GPS measurements

    Science.gov (United States)

    Stolle, C.; Schlüter, S.; Jacobi, C.; Jakowski, N.

    When radio waves as sended by the naviagtion system GPS are passing through the ionosphere they are subject to delays in phase, travel time and polarisation which is an effect of the free electrons. The measured integrated value of Total Electron Content can be utilised for three-dimensional reconstruction of electron density patterns in the ionosphere. Here a tomographic approach is represented. Scince the distribution of data is very sparse and patchy we decided for an algebraic iterative algorithm. The ground based GPS data collected by IGS receivers can be combined by space based GPS of radio limb sounding, incoherent scatter radar and ionosondes data. Hereby, radio occultation data improve beside the amount of available data especially the vertical resolution of electron density distribution. Ionosonde peack electron densities are taken as stop criteria determination for iteration. Reconstructed ionospheric scenarios and validations of the system by independent measurements are presented.

  11. Moon Phases

    Science.gov (United States)

    Riddle, Bob

    2010-01-01

    When teaching Moon phases, the focus seems to be on the sequence of Moon phases and, in some grade levels, how Moon phases occur. Either focus can sometimes be a challenge, especially without the use of models and observations of the Moon. In this month's column, the author describes some of the lessons that he uses to teach the phases of the Moon…

  12. Three-dimension reconstruction based on spatial light modulator

    Energy Technology Data Exchange (ETDEWEB)

    Deng Xuejiao; Zhang Nanyang; Zeng Yanan; Yin Shiliang; Wang Weiyu, E-mail: daisydelring@yahoo.com.cn [Huazhong University of Science and Technology (China)

    2011-02-01

    Three-dimension reconstruction, known as an important research direction of computer graphics, is widely used in the related field such as industrial design and manufacture, construction, aerospace, biology and so on. Via such technology we can obtain three-dimension digital point cloud from a two-dimension image, and then simulate the three-dimensional structure of the physical object for further study. At present, the obtaining of three-dimension digital point cloud data is mainly based on the adaptive optics system with Shack-Hartmann sensor and phase-shifting digital holography. Referring to surface fitting, there are also many available methods such as iterated discrete fourier transform, convolution and image interpolation, linear phase retrieval. The main problems we came across in three-dimension reconstruction are the extraction of feature points and arithmetic of curve fitting. To solve such problems, we can, first of all, calculate the relevant surface normal vector information of each pixel in the light source coordinate system, then these vectors are to be converted to the coordinates of image through the coordinate conversion, so the expectant 3D point cloud get arise. Secondly, after the following procedures of de-noising, repairing, the feature points can later be selected and fitted to get the fitting function of the surface topography by means of Zernike polynomial, so as to reconstruct the determinand's three-dimensional topography. In this paper, a new kind of three-dimension reconstruction algorithm is proposed, with the assistance of which, the topography can be estimated from its grayscale at different sample points. Moreover, the previous stimulation and the experimental results prove that the new algorithm has a strong capability to fit, especially for large-scale objects .

  13. Three-dimension reconstruction based on spatial light modulator

    Science.gov (United States)

    Deng, Xuejiao; Zhang, Nanyang; Zeng, Yanan; Yin, Shiliang; Wang, Weiyu

    2011-02-01

    Three-dimension reconstruction, known as an important research direction of computer graphics, is widely used in the related field such as industrial design and manufacture, construction, aerospace, biology and so on. Via such technology we can obtain three-dimension digital point cloud from a two-dimension image, and then simulate the three-dimensional structure of the physical object for further study. At present, the obtaining of three-dimension digital point cloud data is mainly based on the adaptive optics system with Shack-Hartmann sensor and phase-shifting digital holography. Referring to surface fitting, there are also many available methods such as iterated discrete fourier transform, convolution and image interpolation, linear phase retrieval. The main problems we came across in three-dimension reconstruction are the extraction of feature points and arithmetic of curve fitting. To solve such problems, we can, first of all, calculate the relevant surface normal vector information of each pixel in the light source coordinate system, then these vectors are to be converted to the coordinates of image through the coordinate conversion, so the expectant 3D point cloud get arise. Secondly, after the following procedures of de-noising, repairing, the feature points can later be selected and fitted to get the fitting function of the surface topography by means of Zernike polynomial, so as to reconstruct the determinand's three-dimensional topography. In this paper, a new kind of three-dimension reconstruction algorithm is proposed, with the assistance of which, the topography can be estimated from its grayscale at different sample points. Moreover, the previous stimulation and the experimental results prove that the new algorithm has a strong capability to fit, especially for large-scale objects .

  14. Computational methods estimating uncertainties for profile reconstruction in scatterometry

    Science.gov (United States)

    Gross, H.; Rathsfeld, A.; Scholze, F.; Model, R.; Bär, M.

    2008-04-01

    The solution of the inverse problem in scatterometry, i.e. the determination of periodic surface structures from light diffraction patterns, is incomplete without knowledge of the uncertainties associated with the reconstructed surface parameters. With decreasing feature sizes of lithography masks, increasing demands on metrology techniques arise. Scatterometry as a non-imaging indirect optical method is applied to periodic line-space structures in order to determine geometric parameters like side-wall angles, heights, top and bottom widths and to evaluate the quality of the manufacturing process. The numerical simulation of the diffraction process is based on the finite element solution of the Helmholtz equation. The inverse problem seeks to reconstruct the grating geometry from measured diffraction patterns. Restricting the class of gratings and the set of measurements, this inverse problem can be reformulated as a non-linear operator equation in Euclidean spaces. The operator maps the grating parameters to the efficiencies of diffracted plane wave modes. We employ a Gauss-Newton type iterative method to solve this operator equation and end up minimizing the deviation of the measured efficiency or phase shift values from the simulated ones. The reconstruction properties and the convergence of the algorithm, however, is controlled by the local conditioning of the non-linear mapping and the uncertainties of the measured efficiencies or phase shifts. In particular, the uncertainties of the reconstructed geometric parameters essentially depend on the uncertainties of the input data and can be estimated by various methods. We compare the results obtained from a Monte Carlo procedure to the estimations gained from the approximative covariance matrix of the profile parameters close to the optimal solution and apply them to EUV masks illuminated by plane waves with wavelengths in the range of 13 nm.

  15. A methodology to event reconstruction from trace images.

    Science.gov (United States)

    Milliet, Quentin; Delémont, Olivier; Sapin, Eric; Margot, Pierre

    2015-03-01

    The widespread use of digital imaging devices for surveillance (CCTV) and entertainment (e.g., mobile phones, compact cameras) has increased the number of images recorded and opportunities to consider the images as traces or documentation of criminal activity. The forensic science literature focuses almost exclusively on technical issues and evidence assessment [1]. Earlier steps in the investigation phase have been neglected and must be considered. This article is the first comprehensive description of a methodology to event reconstruction using images. This formal methodology was conceptualised from practical experiences and applied to different contexts and case studies to test and refine it. Based on this practical analysis, we propose a systematic approach that includes a preliminary analysis followed by four main steps. These steps form a sequence for which the results from each step rely on the previous step. However, the methodology is not linear, but it is a cyclic, iterative progression for obtaining knowledge about an event. The preliminary analysis is a pre-evaluation phase, wherein potential relevance of images is assessed. In the first step, images are detected and collected as pertinent trace material; the second step involves organising and assessing their quality and informative potential. The third step includes reconstruction using clues about space, time and actions. Finally, in the fourth step, the images are evaluated and selected as evidence. These steps are described and illustrated using practical examples. The paper outlines how images elicit information about persons, objects, space, time and actions throughout the investigation process to reconstruct an event step by step. We emphasise the hypothetico-deductive reasoning framework, which demonstrates the contribution of images to generating, refining or eliminating propositions or hypotheses. This methodology provides a sound basis for extending image use as evidence and, more generally

  16. Modification of the reconstruction distance of Fresnel holograms for display with multiple spatial light modulators

    Science.gov (United States)

    Leportier, Thibault; Park, Min-Chul; Kim, Taegeun

    2016-06-01

    In digital holography, spatial light modulators (SLMs) devices are used to display the holographic patterns. However, modulation is imperfect because SLMs cannot modulate phase and amplitude at the same time. Then undesired terms such as twin image can be observed in the image plane. One solution to remove twin image contribution without physical spatial filter is to perform complex modulation. Phase and amplitude modulation can be performed sequentially with two different SLMs. Similarly, real and imaginary part of hologram can be displayed and combined in an additive configuration through a polarizing beam splitter. In both case, a major problem is the alignment of the two display devices since misalignment as small as one pixel may degrade significantly quality of the reconstruction. For our experiment, we used data computed numerically to obtain separately real and imaginary part of hologram. Then, we focused on additive configuration where two SLMs are displaying real and imaginary part of hologram respectively. Reconstruction distance of hologram is fixed and distance between SLM and beam splitter should be the same for the two devices. In this paper, we study the effect of having different reconstruction distance for the real and imaginary hologram. We performed simulations and explained the result with the scalar diffraction theory. A method to compensate numerically the reconstruction distance is proposed for on-axis configuration. This method can also be applied to modify reconstruction distance of Fresnel hologram displayed with a single SLM and has potential application in RGB holographic reconstruction

  17. Reconstruction of Anacostia wetlands: success?

    Science.gov (United States)

    Hammerschlag, R.S.; Perry, M.C.

    2002-01-01

    Historically, the tidal Anacostia River in Washington, D.C. had been an extensive system of freshwater tidal marshes replete with a full array of wetland vegetation dominated by wild rice. The local Nacochtank Indians had found the abundant fish and wildlife sufficient to sustain their daily lives. White man's intrusion upon the landscape gradually brought about deterioration of the natural (and associated cultural) system. Total demise followed mid-20th century dredge and fill channelization, which was conducted from the confluence of the Anacostia with the Potomac near the heart of Washington, D.C. to the terminus of the tidal regime at Bladensburg, Maryland. The National Park Service (NPS) became the manager for much of the land along the Anacostia, particularly the eastern bank. As part of its planning effort, the NPS envisioned returning portions of the Anacostia under its control to a natural system as a vignette. The concept was based on bringing back as comprehensive a collection of vegetation and wildlife as possible through the reestablishment of tidal marshes at Kenilworth and Kingman. The resultant wetlands were to be made accessible to the public both logistically and through a well designed interpretative program. In fact, this vision has been realized due to an impressive cooperative effort among a number of Federal and local agencies and organizations. In 1993, 32 acres of freshwater tidal marsh were reconstructed at Kenilworth. Based upon the 5-year monitoring program that has been in place since reconstruction, several generalizations may be made concerning the degree of success of the marsh reconstruction. Water quality in the marsh system and nearby tidal waters has not been noticeably improved. The poor quality may be clue to the overwhelmingly high loads (e.g., sediment, nutrients, etc.) brought in on the twice daily tidal cycle from the Anacostia and to the relatively small volume of water which actually interacts with the emergent marsh

  18. Reconstruction of spectral solar irradiance since 1700 from simulated magnetograms

    Science.gov (United States)

    Dasi-Espuig, M.; Jiang, J.; Krivova, N. A.; Solanki, S. K.; Unruh, Y. C.; Yeo, K. L.

    2016-05-01

    Aims: We present a reconstruction of the spectral solar irradiance since 1700 using the SATIRE-T2 (Spectral And Total Irradiance REconstructions for the Telescope era version 2) model. This model uses as input magnetograms simulated with a surface flux transport model fed with semi-synthetic records of emerging sunspot groups. Methods: The record of sunspot group areas and positions from the Royal Greenwich Observatory (RGO) is only available since 1874. We used statistical relationships between the properties of sunspot group emergence, such as the latitude, area, and tilt angle, and the sunspot cycle strength and phase to produce semi-synthetic sunspot group records starting in the year 1700. The semi-synthetic records are fed into a surface flux transport model to obtain daily simulated magnetograms that map the distribution of the magnetic flux in active regions (sunspots and faculae) and their decay products on the solar surface. The magnetic flux emerging in ephemeral regions is accounted for separately based on the concept of extended cycles whose length and amplitude are linked to those of the sunspot cycles through the sunspot number. The magnetic flux in each surface component (sunspots, faculae and network, and ephemeral regions) was used to compute the spectral and total solar irradiance (TSI) between the years 1700 and 2009. This reconstruction is aimed at timescales of months or longer although the model returns daily values. Results: We found that SATIRE-T2, besides reproducing other relevant observations such as the total magnetic flux, reconstructs the TSI on timescales of months or longer in good agreement with the PMOD composite of observations, as well as with the reconstruction starting in 1878 based on the RGO-SOON data. The model predicts an increase in the TSI of 1.2+0.2-0.3 Wm-2 between 1700 and the present. The spectral irradiance reconstruction is in good agreement with the UARS/SUSIM measurements as well as the Lyman-α composite. The

  19. Immediate Debridement and Reconstruction with

    Directory of Open Access Journals (Sweden)

    Hyoseob Lim

    2012-01-01

    Full Text Available Background Poststernotomy mediastinitis is a rare, but life-threatening complication,thus early diagnosis and proper management is essential for poststernotomy mediastinitis.The main treatment for mediastinitis is aggressive debridement. Several options exist forreconstruction of defects after debridement. The efficacy of immediate debridement andreconstruction with a pectoralis major muscle flap designed for the defect immediately afterthe diagnosis of poststernotomy mediastinitis is demonstrated.Methods Between September 2009 and June 2011, 6 patients were referred to the Departmentof Plastic and Reconstructive Surgery and the Department of Thoracic and CardiovascularSurgery of Ajou University Hospital for poststernotomy mediastinitis. All of the patientsunderwent extensive debridement and reconstruction with pectoralis major muscle flaps,advanced based on the pedicle of the thoracoacromial artery as soon as possible followingdiagnosis. A retrospective review of the 6 cases was performed to evaluate infection control,postoperative morbidity, and mortality.Results All patients had complete wound closures and reduced severity of infections basedon the erythrocyte sedimentation rate and C-reactive protein levels and a reduction inpoststernal fluid collection on computed tomography an average of 6 days postoperatively.A lack of growth of organisms in the wound culture was demonstrated after 3 weeks. Therewere no major wound morbidities, such as hematomas, but one minor complication requireda skin graft caused by skin flap necrosis. No patient expired after definitive surgery.Conclusions Immediate debridement and reconstruction using a pectoralis major muscle flapis a safe technique for managing infections associated with poststernotomy mediastinitis,and is associated with minimal morbidity and mortality.

  20. Reconstructive options in pelvic tumours

    Directory of Open Access Journals (Sweden)

    Mayilvahanan N

    2005-01-01

    Full Text Available Background: Pelvic tumours present a complex problem. It is difficult to choose between limb salvage and hemipelvectomy. Method: Forty three patients of tumours of pelvis underwent limb salvage resection with reconstruction in 32 patients. The majority were chondrosarcomas (20 cases followed by Ewing sarcoma. Stage II B was the most common stage in malignant lesions and all the seven benign lesions were aggressive (B3. Surgical margins achieved were wide in 31 and marginal in 12 cases. Ilium was involved in 51% of cases and periacetabular involvement was seen in 12 patients. The resections done were mostly of types I &II of Enneking′s classification of pelvic resection. Arthrodesis was attempted in 24 patients. Customized Saddle prosthesis was used in seven patients and no reconstruction in 12 patients. Adjuvant chemotherapy was given to all high-grade malignant tumours, combined with radiotherapy in 7 patients. Results: With a mean follow up of 48.5 months and one patient lost to follow up, the recurrence rate among the evaluated cases was 16.6%. Oncologically, 30 patients were continuously disease free with 7 local recurrences and 4 deaths due to disseminated disease and 2 patients died of other causes. During the initial years, satisfactory functional results were achieved with prosthetic replacement. Long-term functional result of 36 patients who were alive at the time of latest follow up was satisfactory in 75% who underwent arthrodesis and in those where no reconstruction was used. We also describe a method of new classification of pelvic resections that clarifies certain shortcomings of the previous systems of classification. Conclusion: Selection of a procedure depends largely on the patient factors, the tumour grade, the resultant defect and the tissue factors. Resection with proper margins gives better functional and oncological results

  1. [Reconstruction of facial burn sequelae].

    Science.gov (United States)

    Foyatier, J L; Comparin, J P; Boulos, J P; Bichet, J C; Jacquin, F

    2001-06-01

    The deep burns of the face can lead to horrible scars functionally and aesthetically. Treatment of these scars need several surgical interventions frequently and during many years. In our region we deal with this type of wounds as team work, multidisciplinary approach carrying out many process starting by emergency treatment of acute burns till the social rehabilitation. The expansion technique was great help in improving the shape of scars, by using the expanding skin as full thickness grafts. Reconstruction of the anatomical units and application of aesthetic techniques (like rhinoplasty, lifting, tattooing and autologous fat injections) participate equally in improving the quality of results. Many examples of treatments of burns scars are shown.

  2. Reconstructing NURBS Surface with Features

    Institute of Scientific and Technical Information of China (English)

    SUN Chunhua

    2006-01-01

    The method of reconstructing NURBS surface with features is proposed in this paper. Features including boundary curves and feature points are recognized from the scanned data. An initial surface is constructed with boundary curves. The desired NURBS is determined by modifying the initial surface to pass through feature points. Lagrange multiplier is used to find the solution. The error analysis is then done. Examples are given to verify the algorithm at last. The method can keep some features fixed and be widely used in CAD modeling.

  3. Computed laminography and reconstruction algorithm

    Institute of Scientific and Technical Information of China (English)

    QUE Jie-Min; YU Zhong-Qiang; YAN Yong-Lian; CAO Da-Quan; ZHAO Wei; TANG Xiao; SUN Cui-Li; WANG Yan-Fang; WEI Cun-Feng; SHI Rong-Jian; WEI Long

    2012-01-01

    Computed laminography (CL) is an alternative to computed tomography if large objects are to be inspected with high resolution.This is especially true for planar objects.In this paper,we set up a new scanning geometry for CL,and study the algebraic reconstruction technique (ART) for CL imaging.We compare the results of ART with variant weighted functions by computer simulation with a digital phantom.It proves that ART algorithm is a good choice for the CL system.

  4. Reconstructing past fractional record values

    Directory of Open Access Journals (Sweden)

    Magdy E. El-Adll

    2016-10-01

    Full Text Available In this paper, reconstructing past fractional upper (lower records from any absolutely continuous distribution is proposed. For this purpose, two pivotal quantities are given and their exact distributions are derived. More detailed results, including the case of unknown parameters, are given for the exponential and Fre´chet distributions. Moreover, the exact mean square reconstructor errors are obtained and some comparisons between the pivotal quantities are performed. To explore the efficiency of the obtained results, a simulation study is conducted and two real data sets are analyzed.

  5. Reconstruction of Space Steel Constructions

    OpenAIRE

    BRODNIANSKY, Jan; AGOCS, Zoltan; AROCH, Rudolf; SLIVANSKY, Milos

    2010-01-01

    p. 1328-1337 Reconstruction of some special types of constructions - silos, timber roof structure and a winter stadium are described. The silos are cylindrical with a diameter of 36.0m with a total height of 50.5m. The silo shell is made from steel plates of variable thickness. Capacity of the silo is 60 000t. Gradually, during more than 30 years of operation, local deformations and distinctive 6000mm high cracks in the bottom part of the shells of the silos developed. On the basis o...

  6. Economics of abdominal wall reconstruction.

    Science.gov (United States)

    Bower, Curtis; Roth, J Scott

    2013-10-01

    The economic aspects of abdominal wall reconstruction are frequently overlooked, although understandings of the financial implications are essential in providing cost-efficient health care. Ventral hernia repairs are frequently performed surgical procedures with significant economic ramifications for employers, insurers, providers, and patients because of the volume of procedures, complication rates, the significant rate of recurrence, and escalating costs. Because biological mesh materials add significant expense to the costs of treating complex abdominal wall hernias, the role of such costly materials needs to be better defined to ensure the most cost-efficient and effective treatments for ventral abdominal wall hernias.

  7. Time-frequency manifold sparse reconstruction: A novel method for bearing fault feature extraction

    Science.gov (United States)

    Ding, Xiaoxi; He, Qingbo

    2016-12-01

    In this paper, a novel transient signal reconstruction method, called time-frequency manifold (TFM) sparse reconstruction, is proposed for bearing fault feature extraction. This method introduces image sparse reconstruction into the TFM analysis framework. According to the excellent denoising performance of TFM, a more effective time-frequency (TF) dictionary can be learned from the TFM signature by image sparse decomposition based on orthogonal matching pursuit (OMP). Then, the TF distribution (TFD) of the raw signal in a reconstructed phase space would be re-expressed with the sum of learned TF atoms multiplied by corresponding coefficients. Finally, one-dimensional signal can be achieved again by the inverse process of TF analysis (TFA). Meanwhile, the amplitude information of the raw signal would be well reconstructed. The proposed technique combines the merits of the TFM in denoising and the atomic decomposition in image sparse reconstruction. Moreover, the combination makes it possible to express the nonlinear signal processing results explicitly in theory. The effectiveness of the proposed TFM sparse reconstruction method is verified by experimental analysis for bearing fault feature extraction.

  8. Parallel-quadrature phase-shifting digital holographic microscopy using polarization beam splitter.

    Science.gov (United States)

    Das, Bhargab; Yelleswarapu, Chandra S; Rao, Dvgln

    2012-11-01

    We present a digital holography microscopy technique based on parallel-quadrature phase-shifting method. Two π/2 phase-shifted holograms are recorded simultaneously using polarization phase-shifting principle, slightly off-axis recording geometry, and two identical CCD sensors. The parallel phase-shifting is realized by combining circularly polarized object beam with a 45° degree polarized reference beam through a polarizing beam splitter. DC term is eliminated by subtracting the two holograms from each other and the object information is reconstructed after selecting the frequency spectrum of the real image. Both amplitude and phase object reconstruction results are presented. Simultaneous recording eliminates phase errors caused by mechanical vibrations and air turbulences. The slightly off-axis recording geometry with phase-shifting allows a much larger dimension of the spatial filter for reconstruction of the object information. This leads to better reconstruction capability than traditional off-axis holography.

  9. Extension of the modal wave-front reconstruction algorithm to non-uniform illumination.

    Science.gov (United States)

    Ma, Xiaoyu; Mu, Jie; Rao, ChangHui; Yang, Jinsheng; Rao, XueJun; Tian, Yu

    2014-06-30

    Attempts are made to eliminate the effects of non-uniform illumination on the precision of wave-front measurement. To achieve this, the relationship between the wave-front slope at a single sub-aperture and the distributions of the phase and light intensity of the wave-front were first analyzed to obtain the relevant theoretical formulae. Then, based on the principle of modal wave-front reconstruction, the influence of the light intensity distribution on the wave-front slope is introduced into the calculation of the reconstruction matrix. Experiments were conducted to prove that the corrected modal wave-front reconstruction algorithm improved the accuracy of wave-front reconstruction. Moreover, the correction is conducive to high-precision wave-front measurement using a Hartmann wave-front sensor in the presence of non-uniform illumination.

  10. Cosmological reconstruction and {\\it Om} diagnostic analysis of Einstein-Aether Theory

    CERN Document Server

    Pasqua, Antonio; Momeni, Davood; Raza, Muhammad; Myrzakulov, Ratbay

    2015-01-01

    Cosmological reconstruction technique is applied to study the cosmology of the Einstein-Aether (EA) gravity. We reconstructed an analytical model of EA theory for a type of Hubble dependent dark energy density proposed by Granda and Oliveros. The reconstructed cosmological scale factors are comprised of power-law, future singular model, emergent scale factor, intermediate scale factor, a unified theory for matter and dark energy dominated phases and finally for a type of non-extensive exponential scale factor, the q-de Sitter scale factor. In each cosmological epoch, we reconstruct the Lagrangian of the vector part of theory $F(K)$. Furthermore, \\emph{Om} diagnostic analysis technique is applied to fit parameters using recent observational data, namely Type Ia Supernovae, BAO, and data of Hubble parameter.

  11. NOISE AMPLIFICATION ANALYSIS AND COMPARISON OF TWO PERIODIC NONUNIFORM SAMPLING RECONSTRUCTION METHODS USED IN DPCA SAR

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    General Sampling Expansion Reconstruction Method(GSERM)and Digital Spectrum Reconstruction Method(DSRM),which prove effective to reconstruct azimuth signal of Displaced Phase Center Apertures(DPCA) Synthetic Aperture areal"(SAR)system from its Periodic Non-Uniform Sampling(PNUS)data sequences,would amplify the noise and sidelobe clutter simultaneously in the reconstruction.This paper formulates the relation of the system transfer matrixes of the above two methods,gives the properties,such aS periodicity,symmetry,and time-shift property,of their Noise and Sidelobe Clutter Amplification Factor(NSCAF),and discovers that DSRM is more sensitive than GSERM in the white noise environment.In addition,criteria based on initial sampling point analysis for the robust PRF selection are suggested.Computer simulation results support these con-clusions.

  12. Enhanced image reconstruction of three-dimensional fluorescent assays by subtractive structured-light illumination microscopy.

    Science.gov (United States)

    Choi, Jong-ryul; Kim, Donghyun

    2012-10-01

    We investigate improved image reconstruction of structured light illumination for high-resolution imaging of three-dimensional (3D) cell-based assays. For proof of concept, an in situ fluorescence optical detection system was built with a digital micromirror device as a spatial light modulator, for which phase and tilting angle in a grid pattern were varied to implement specific image reconstruction schemes. Subtractive reconstruction algorithms based on structured light illumination were used to acquire images of fluorescent microbeads deposited as a two-dimensional monolayer or in 3D alginate matrix. We have confirmed that an optical subtraction algorithm improves axial and lateral resolution by effectively removing out-of-focus fluorescence. The results suggest that subtractive image reconstruction can be useful for structured illumination microscopy of broad types of cell-based assays with high image resolution.

  13. Sequence-Length Requirement of Distance-Based Phylogeny Reconstruction: Breaking the Polynomial Barrier

    CERN Document Server

    Roch, Sebastien

    2009-01-01

    We introduce a new distance-based phylogeny reconstruction technique which provably achieves, at sufficiently short branch lengths, a polylogarithmic sequence-length requirement -- improving significantly over previous polynomial bounds for distance-based methods. The technique is based on an averaging procedure that implicitly reconstructs ancestral sequences. In the same token, we extend previous results on phase transitions in phylogeny reconstruction to general time-reversible models. More precisely, we show that in the so-called Kesten-Stigum zone (roughly, a region of the parameter space where ancestral sequences are well approximated by ``linear combinations'' of the observed sequences) sequences of length $\\poly(\\log n)$ suffice for reconstruction when branch lengths are discretized. Here $n$ is the number of extant species. Our results challenge, to some extent, the conventional wisdom that estimates of evolutionary distances alone carry significantly less information about phylogenies than full sequ...

  14. Method for position emission mammography image reconstruction

    Science.gov (United States)

    Smith, Mark Frederick

    2004-10-12

    An image reconstruction method comprising accepting coincidence datat from either a data file or in real time from a pair of detector heads, culling event data that is outside a desired energy range, optionally saving the desired data for each detector position or for each pair of detector pixels on the two detector heads, and then reconstructing the image either by backprojection image reconstruction or by iterative image reconstruction. In the backprojection image reconstruction mode, rays are traced between centers of lines of response (LOR's), counts are then either allocated by nearest pixel interpolation or allocated by an overlap method and then corrected for geometric effects and attenuation and the data file updated. If the iterative image reconstruction option is selected, one implementation is to compute a grid Siddon retracing, and to perform maximum likelihood expectation maiximization (MLEM) computed by either: a) tracing parallel rays between subpixels on opposite detector heads; or b) tracing rays between randomized endpoint locations on opposite detector heads.

  15. Helical mode lung 4D-CT reconstruction using Bayesian model.

    Science.gov (United States)

    He, Tiancheng; Xue, Zhong; Nitsch, Paige L; Teh, Bin S; Wong, Stephen T

    2013-01-01

    4D computed tomography (CT) has been widely used for treatment planning of thoracic and abdominal cancer radiotherapy. Current 4D-CT lung image reconstruction methods rely on respiratory gating to rearrange the large number of axial images into different phases, which may be subject to external surrogate errors due to poor reproducibility of breathing cycles. New image-matching-based reconstruction works better for the cine mode of 4D-CT acquisition than the helical mode because the table position of each axial image is different in helical mode and image matching might suffer from bigger errors. In helical mode, not only the phases but also the un-uniform table positions of images need to be considered. We propose a Bayesian method for automated 4D-CT lung image reconstruction in helical mode 4D scans. Each axial image is assigned to a respiratory phase based on the Bayesian framework that ensures spatial and temporal smoothness of surfaces of anatomical structures. Iterative optimization is used to reconstruct a series of 3D-CT images for subjects undergoing 4D scans. In experiments, we compared visually and quantitatively the results of the proposed Bayesian 4D-CT reconstruction algorithm with the respiratory surrogate and the image matching-based method. The results showed that the proposed algorithm yielded better 4D-CT for helical scans.

  16. The Theory of Variances in Equilibrium Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Zakharov, Leonid E.; Lewandowski, Jerome; Foley, Elizabeth L.; Levinton, Fred M.; Yuh, Howard Y.; Drozdov, Vladimir; McDonald, Darren

    2008-01-14

    The theory of variances of equilibrium reconstruction is presented. It complements existing practices with information regarding what kind of plasma profiles can be reconstructed, how accurately, and what remains beyond the abilities of diagnostic systems. The σ-curves, introduced by the present theory, give a quantitative assessment of quality of effectiveness of diagnostic systems in constraining equilibrium reconstructions. The theory also suggests a method for aligning the accuracy of measurements of different physical nature.

  17. Primary vertex reconstruction with the ATLAS detector

    CERN Document Server

    Meloni, Federico; The ATLAS collaboration

    2016-01-01

    Efficient and precise reconstruction of the primary vertex in a LHC collision is essential for determining the full kinematic properties of a hard-scatter event and of soft interactions as a measure of the amount of pile-up. The reconstruction of primary vertices in the busy, high pile-up environment of Run-2 of the LHC is a challenging task. The algorithms developed by the ATLAS experiments to reconstruct multiple vertices with small spatial separation are presented.

  18. Plate tectonic raster reconstruction in GPlates

    OpenAIRE

    2014-01-01

    We describe a novel method implemented in the GPlates plate tectonic reconstruction software to interactively reconstruct arbitrarily high-resolution raster data to past geological times using a rotation model. The approach is based on the projection of geo-referenced raster data into a cube map followed by a reverse projection onto rotated tectonic plates on the surface of the globe. This decouples the rendering of a geo-referenced raster from its reconstruction, providing ...

  19. Track and Vertex Reconstruction in CMS

    CERN Document Server

    Adam, W

    2006-01-01

    The CMS experiment relies on a Silicon pixel and micro-strip tracker for the reconstruction of tracks and vertices of charged particles in the harsh environment of proton and heavy-ion collisions at the LHC at CERN. An outline of the basic track and vertex reconstruction algorithms used in CMS is given and their performance is described. Results of more advanced algorithms like the Gaussian Sum Filter for electron reconstruction and robust vertex fitters are shown.

  20. Reconstruction Threshold for the Hardcore Model

    CERN Document Server

    Bhatnagar, Nayantara; Tetali, Prasad

    2010-01-01

    In this paper we consider the reconstruction problem on the tree for the hardcore model. We determine new bounds for the non-reconstruction regime on the k-regular tree showing non-reconstruction when lambda (e+o(1))ln^2(k). We discuss the relationship for finding large independent sets in sparse random graphs and to the mixing time of Markov chains for sampling independent sets on trees.

  1. Considerations on Xi- reconstruction in LHCb

    CERN Document Server

    Brochu, F M

    2016-01-01

    This paper describes an alternative method of charged hyperon reconstruction applicable to the LHCb experiment. It extends the seminal work of the FOCUS collaboration to the specific detector layout of LHCb and addresses the reconstruction ambiguities reported in their earlier work, leading to improvements in the reconstruction efficiency for the specific cases of Xi- and Omega- baryon decays to a charged meson and a Lambda baryon.

  2. Reconstruction Formulas for Photoacoustic Sectional Imaging

    CERN Document Server

    Elbau, Peter; Schulze, Rainer

    2011-01-01

    The literature on reconstruction formulas for photoacoustic tomography (PAT) is vast. The various reconstruction formulas differ by used measurement devices and geometry on which the data are sampled. In standard photoacoustic imaging (PAI), the object under investigation is illuminated uniformly. Recently, sectional photoacoustic imaging techniques, using focusing techniques for initializing and measuring the pressure along a plane, appeared in the literature. This paper surveys existing and provides novel exact reconstruction formulas for sectional photoacoustic imaging.

  3. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M. (comp.)

    1990-01-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Pacific Northwest Laboratory (PNL) under the direction of an independent Technical Steering Panel (TSP). The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates). The Source Terms Task develops estimates of radioactive emissions from Hanford facilities since 1944. The Environmental Transport Task reconstructs the movement of radioactive materials from the areas of release to populations. The Environmental Monitoring Data Task assembles, evaluates, and reports historical environmental monitoring data. The Demographics, Agriculture, Food Habits Task develops the data needed to identify the populations that could have been affected by the releases. In addition to population and demographic data, the food and water resources and consumption patterns for populations are estimated because they provide a primary pathway for the intake of radionuclides. The Environmental Pathways and Dose Estimates Task use the information produced by the other tasks to estimate the radiation doses populations could have received from Hanford radiation. Project progress is documented in this monthly report, which is available to the public. 3 figs., 3 tabs.

  4. ENO reconstruction and ENO interpolation are stable

    CERN Document Server

    Fjordholm, Ulrik S; Tadmor, Eitan

    2011-01-01

    We prove stability estimates for the ENO reconstruction and ENO interpolation procedures. In particular, we show that the jump of the reconstructed ENO pointvalues at each cell interface has the same sign as the jump of the underlying cell averages across that interface. We also prove that the jump of the reconstructed values can be upper-bounded in terms of the jump of the underlying cell averages. Similar sign properties hold for the ENO interpolation procedure. These estimates, which are shown to hold for ENO reconstruction and interpolation of arbitrary order of accuracy and on non-uniform meshes, indicate a remarkable rigidity of the piecewise-polynomial ENO procedure.

  5. Distributed Reconstruction via Alternating Direction Method

    Directory of Open Access Journals (Sweden)

    Linyuan Wang

    2013-01-01

    Full Text Available With the development of compressive sensing theory, image reconstruction from few-view projections has received considerable research attentions in the field of computed tomography (CT. Total-variation- (TV- based CT image reconstruction has been shown to be experimentally capable of producing accurate reconstructions from sparse-view data. In this study, a distributed reconstruction algorithm based on TV minimization has been developed. This algorithm is very simple as it uses the alternating direction method. The proposed method can accelerate the alternating direction total variation minimization (ADTVM algorithm without losing accuracy.

  6. Reconstruction of convex bodies from surface tensors

    DEFF Research Database (Denmark)

    Kousholt, Astrid; Kiderlen, Markus

    We present two algorithms for reconstruction of the shape of convex bodies in the two-dimensional Euclidean space. The first reconstruction algorithm requires knowledge of the exact surface tensors of a convex body up to rank s for some natural number s. The second algorithm uses harmonic intrinsic...... volumes which are certain values of the surface tensors and allows for noisy measurements. From a generalized version of Wirtinger's inequality, we derive stability results that are utilized to ensure consistency of both reconstruction procedures. Consistency of the reconstruction procedure based...

  7. Reconstruction of congenital defects of the vagina.

    Science.gov (United States)

    Eldor, Liron; Friedman, Jeffrey D

    2011-05-01

    Congenital absence of the vagina is a relatively rare condition most commonly associated with Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome. Historically, several reconstructive techniques have been described to provide for functional vaginal reconstruction on these patients, both operative and nonoperative. Although there are many advantages and disadvantages of the various procedures, one experience with the use of split thickness skin grafts to reconstruct the vagina has produced acceptable functional results with limited donor site morbidity. Careful planning and timing of this form of reconstruction can produce predictable results in patients who are nearing sexual maturity.

  8. Advances in Bioprinting Technologies for Craniofacial Reconstruction.

    Science.gov (United States)

    Visscher, Dafydd O; Farré-Guasch, Elisabet; Helder, Marco N; Gibbs, Susan; Forouzanfar, Tymour; van Zuijlen, Paul P; Wolff, Jan

    2016-09-01

    Recent developments in craniofacial reconstruction have shown important advances in both the materials and methods used. While autogenous tissue is still considered to be the gold standard for these reconstructions, the harvesting procedure remains tedious and in many cases causes significant donor site morbidity. These limitations have subsequently led to the development of less invasive techniques such as 3D bioprinting that could offer possibilities to manufacture patient-tailored bioactive tissue constructs for craniofacial reconstruction. Here, we discuss the current technological and (pre)clinical advances of 3D bioprinting for use in craniofacial reconstruction and highlight the challenges that need to be addressed in the coming years.

  9. 基于相空间重构的风电功率波动特性分析及其对预测误差影响%Volatility of Wind Power Sequence and Its Influence on Prediction Error Based on Phase Space Reconstruction

    Institute of Scientific and Technical Information of China (English)

    杨茂; 齐玥

    2015-01-01

    The accurate prediction of wind power is important to guarantee the security and stability of any power system containing a large contribution from wind energy. To improve the accuracy of predictions of wind power generation, many new prediction methods have emerged. However, the accuracy of wind power prediction is not only related to the prediction methods, but also associated with the volatility of wind power. Regardless of the method adopted, it is not possible to guarantee accurate and error-free prediction. The necessity of the volatility in the wind power sequence was explained. To depict the probability of the occurrence of a new volatility mode, based on phase space reconstruction, a recurrence plot, and the recurrence rate was proposed to qualitatively and quantitatively depict the volatility. The changing rules of the recurrence plot and recurrence rate at different spatial scales were discussed. Based on this, a method to analyze the relationship between the volatility of a wind power sequence and prediction error was established. Finally a fair method for evaluating predictions accuracy was provided based on the recurrence rate. The study further illustrates the effectiveness of the method.%精确的风电功率预测是保证含大规模风电电力系统安全稳定运行的重要基础.为提高风电功率预测精度,已开展了诸多研究,新的预测方法不断涌现.但任何方法都无法保证无差预报,究其原因,风电功率的预测精度不但和预测方法有关,还与风电功率波动特性有关.该文阐述了评价风电功率波动特性的必要性;在相空间重构基础上,利用递归图和递归率对风电功率时间序列波动特性分别进行了定性和定量的刻画,以表征风电功率波动新模态产生的机率;分析了不同空间尺度下递归率的变化规律,建立了分析风电功率时间序列波动特性与预测误差关系的方法,最后给出了利用递归率为风电场管理机构

  10. Active numerical model of human body for reconstruction of falls from height.

    Science.gov (United States)

    Milanowicz, Marcin; Kędzior, Krzysztof

    2017-01-01

    Falls from height constitute the largest group of incidents out of approximately 90,000 occupational accidents occurring each year in Poland. Reconstruction of the exact course of a fall from height is generally difficult due to lack of sufficient information from the accident scene. This usually results in several contradictory versions of an incident and impedes, for example, determination of the liability in a judicial process. In similar situations, in many areas of human activity, researchers apply numerical simulation. They use it to model physical phenomena to reconstruct their real course over time; e.g. numerical human body models are frequently used for investigation and reconstruction of road accidents. However, they are validated in terms of specific road traffic accidents and are considerably limited when applied to the reconstruction of other types of accidents. The objective of the study was to develop an active numerical human body model to be used for reconstruction of accidents associated with falling from height. Development of the model involved extension and adaptation of the existing Pedestrian human body model (available in the MADYMO package database) for the purposes of reconstruction of falls from height by taking into account the human reaction to the loss of balance. The model was developed by using the results of experimental tests of the initial phase of the fall from height. The active numerical human body model covering 28 sets of initial conditions related to various human reactions to the loss of balance was developed. The application of the model was illustrated by using it to reconstruct a real fall from height. From among the 28 sets of initial conditions, those whose application made it possible to reconstruct the most probable version of the incident was selected. The selection was based on comparison of the results of the reconstruction with information contained in the accident report. Results in the form of estimated

  11. Accurate stochastic reconstruction of heterogeneous microstructures by limited x-ray tomographic projections.

    Science.gov (United States)

    Li, Hechao; Kaira, Shashank; Mertens, James; Chawla, Nikhilesh; Jiao, Yang

    2016-12-01

    An accurate knowledge of the complex microstructure of a heterogeneous material is crucial for its performance prediction, prognosis and optimization. X-ray tomography has provided a nondestructive means for microstructure characterization in 3D and 4D (i.e. structural evolution over time), in which a material is typically reconstructed from a large number of tomographic projections using filtered-back-projection (FBP) method or algebraic reconstruction techniques (ART). Here, we present in detail a stochastic optimization procedure that enables one to accurately reconstruct material microstructure from a small number of absorption contrast x-ray tomographic projections. This discrete tomography reconstruction procedure is in contrast to the commonly used FBP and ART, which usually requires thousands of projections for accurate microstructure rendition. The utility of our stochastic procedure is first demonstrated by reconstructing a wide class of two-phase heterogeneous materials including sandstone and hard-particle packing from simulated limited-angle projections in both cone-beam and parallel beam projection geometry. It is then applied to reconstruct tailored Sn-sphere-clay-matrix systems from limited-angle cone-beam data obtained via a lab-scale tomography facility at Arizona State University and parallel-beam synchrotron data obtained at Advanced Photon Source, Argonne National Laboratory. In addition, we examine the information content of tomography data by successively incorporating larger number of projections and quantifying the accuracy of the reconstructions. We show that only a small number of projections (e.g. 20-40, depending on the complexity of the microstructure of interest and desired resolution) are necessary for accurate material reconstructions via our stochastic procedure, which indicates its high efficiency in using limited structural information. The ramifications of the stochastic reconstruction procedure in 4D materials science are also

  12. Value of liver computed tomography with iodixanol 270, 80 kVp and iterative reconstruction

    Institute of Scientific and Technical Information of China (English)

    Diomidis Botsikas; Isabelle Barnaure; Sylvain Terraz; Christoph D Becker; Anastasia Kalovidouri; Xavier Montet

    2016-01-01

    AIM: To evaluate the image quality of hepatic multidetector computed tomography(MDCT) with dynamic contrast enhancement. METHODS: It uses iodixanol 270 mg/m L(Visipaque 270) and 80 kVp acquisitions reconstructed with sinogram affirmed iterative reconstruction(SAFIRE?) in comparison with a standard MDCT protocol. Fiftythree consecutive patients with known or suspected hepatocellular carcinoma underwent 55 CT examinations, with two different four-phase CT protocols. The first group of 30 patients underwent a standard 120 kVp acquisition after injection of Iohexol 350 mg/m L(Accupaque 350~?) and reconstructed with filtered back projection. The second group of 25 patients underwent a dual-energy CT at 80-140 kVp with iodixanol 270. The 80 kVp component of the second group was reconstructed iteratively(SAFIRE?-Siemens). All hyperdense and hypodense hepatic lesions ≥ 5 mm were identified with both protocols. Aorta and portal vessels/liver parenchyma contrast to noise ratio(CNR) in arterial phase, hypervascular lesion/liver parenchyma CNR in arterial phase, hypodense lesion/liver parenchyma CNR in portal and late phase were calculated in both groups.RESULTS: Aorta/liver and focal lesions altogether/liver CNR were higher for the second protocol(P = 0.0078 and 0.0346). Hypervascular lesions/liver CNR was not statistically different(P = 0.86). Hypodense lesion/liver CNR in the portal phase was significantly higher for the second group(P = 0.0107). Hypodense lesion/liver CNR in the late phase was the same for both groups(P = 0.9926).CONCLUSION: MDCT imaging with 80 kVp with iterative reconstruction and iodixanol 270 yields equal or even better image quality.

  13. The reconstructed residual error: a novel segmentation evaluation measure for reconstructed images in tomography

    NARCIS (Netherlands)

    Roelandts, T.; Batenburg, K.J.; Dekker, A.J. den; Sijbers, J.

    2014-01-01

    In this paper, we present the reconstructed residual error, which evaluates the quality of a given segmentation of a reconstructed image in tomography. This novel evaluation method, which is independent of the methods that were used to reconstruct and segment the image, is applicable to segmentation

  14. Reconstruction and analysis of hybrid composite shells using meshless methods

    Science.gov (United States)

    Bernardo, G. M. S.; Loja, M. A. R.

    2017-02-01

    The importance of focusing on the research of viable models to predict the behaviour of structures which may possess in some cases complex geometries is an issue that is growing in different scientific areas, ranging from the civil and mechanical engineering to the architecture or biomedical devices fields. In these cases, the research effort to find an efficient approach to fit laser scanning point clouds, to the desired surface, has been increasing, leading to the possibility of modelling as-built/as-is structures and components' features. However, combining the task of surface reconstruction and the implementation of a structural analysis model is not a trivial task. Although there are works focusing those different phases in separate, there is still an effective need to find approaches able to interconnect them in an efficient way. Therefore, achieving a representative geometric model able to be subsequently submitted to a structural analysis in a similar based platform is a fundamental step to establish an effective expeditious processing workflow. With the present work, one presents an integrated methodology based on the use of meshless approaches, to reconstruct shells described by points' clouds, and to subsequently predict their static behaviour. These methods are highly appropriate on dealing with unstructured points clouds, as they do not need to have any specific spatial or geometric requirement when implemented, depending only on the distance between the points. Details on the formulation, and a set of illustrative examples focusing the reconstruction of cylindrical and double-curvature shells, and its further analysis, are presented.

  15. Reconstruction of a 2D seismic wavefield by seismic gradiometry

    Science.gov (United States)

    Maeda, Takuto; Nishida, Kiwamu; Takagi, Ryota; Obara, Kazushige

    2016-12-01

    We reconstructed a 2D seismic wavefield and obtained its propagation properties by using the seismic gradiometry method together with dense observations of the Hi-net seismograph network in Japan. The seismic gradiometry method estimates the wave amplitude and its spatial derivative coefficients at any location from a discrete station record by using a Taylor series approximation. From the spatial derivatives in horizontal directions, the properties of a propagating wave packet, including the arrival direction, slowness, geometrical spreading, and radiation pattern can be obtained. In addition, by using spatial derivatives together with free-surface boundary conditions, the 2D vector elastic wavefield can be decomposed into divergence and rotation components. First, as a feasibility test, we performed an analysis with a synthetic seismogram dataset computed by a numerical simulation for a realistic 3D medium and the actual Hi-net station layout. We confirmed that the wave amplitude and its spatial derivatives were very well-reproduced for period bands longer than 25 s. Applications to a real large earthquake showed that the amplitude and phase of the wavefield were well reconstructed, along with slowness vector. The slowness of the reconstructed wavefield showed a clear contrast between body and surface waves and regional non-great-circle-path wave propagation, possibly owing to scattering. Slowness vectors together with divergence and rotation decomposition are expected to be useful for determining constituents of observed wavefields in inhomogeneous media.

  16. Reconstruction of nonlinear wave propagation

    Science.gov (United States)

    Fleischer, Jason W; Barsi, Christopher; Wan, Wenjie

    2013-04-23

    Disclosed are systems and methods for characterizing a nonlinear propagation environment by numerically propagating a measured output waveform resulting from a known input waveform. The numerical propagation reconstructs the input waveform, and in the process, the nonlinear environment is characterized. In certain embodiments, knowledge of the characterized nonlinear environment facilitates determination of an unknown input based on a measured output. Similarly, knowledge of the characterized nonlinear environment also facilitates formation of a desired output based on a configurable input. In both situations, the input thus characterized and the output thus obtained include features that would normally be lost in linear propagations. Such features can include evanescent waves and peripheral waves, such that an image thus obtained are inherently wide-angle, farfield form of microscopy.

  17. Hermite variational implicit surface reconstruction

    Institute of Scientific and Technical Information of China (English)

    PAN RongJiang; MENG XiangXu; WHANGBO TaegKeun

    2009-01-01

    We propose a new technique for reconstructing surfaces from a large set of unorganized 3D data points and their associated normal vectors. The surface is represented as the zero level set of an implicit vol-ume model which fits the data points and normal constraints. Compared with variational implicit sur-faces, we make use of surface normal vectors at data points directly in the implicit model and avoid of introducing manufactured off-surface points. Given n surface point/normal pairs, the proposed method only needs to solve an n×n positive definite linear system. It allows fitting large datasets effectively and robustly. We demonstrate the performance of the proposed method with both globally supported and compactly supported radial basis functions on several datasets.

  18. Automatic Network Reconstruction using ASP

    CERN Document Server

    Ostrowski, Max; Durzinsky, Markus; Marwan, Wolfgang; Wagler, Annegret

    2011-01-01

    Building biological models by inferring functional dependencies from experimental data is an im- portant issue in Molecular Biology. To relieve the biologist from this traditionally manual process, various approaches have been proposed to increase the degree of automation. However, available ap- proaches often yield a single model only, rely on specific assumptions, and/or use dedicated, heuris- tic algorithms that are intolerant to changing circumstances or requirements in the view of the rapid progress made in Biotechnology. Our aim is to provide a declarative solution to the problem by ap- peal to Answer Set Programming (ASP) overcoming these difficulties. We build upon an existing approach to Automatic Network Reconstruction proposed by part of the authors. This approach has firm mathematical foundations and is well suited for ASP due to its combinatorial flavor providing a characterization of all models explaining a set of experiments. The usage of ASP has several ben- efits over the existing heuristic a...

  19. Neural Network for Sparse Reconstruction

    Directory of Open Access Journals (Sweden)

    Qingfa Li

    2014-01-01

    Full Text Available We construct a neural network based on smoothing approximation techniques and projected gradient method to solve a kind of sparse reconstruction problems. Neural network can be implemented by circuits and can be seen as an important method for solving optimization problems, especially large scale problems. Smoothing approximation is an efficient technique for solving nonsmooth optimization problems. We combine these two techniques to overcome the difficulties of the choices of the step size in discrete algorithms and the item in the set-valued map of differential inclusion. In theory, the proposed network can converge to the optimal solution set of the given problem. Furthermore, some numerical experiments show the effectiveness of the proposed network in this paper.

  20. Reformulating and Reconstructing Quantum Theory

    CERN Document Server

    Hardy, Lucien

    2011-01-01

    We provide a reformulation of finite dimensional quantum theory in the circuit framework in terms of mathematical axioms, and a reconstruction of quantum theory from operational postulates. The mathematical axioms for quantum theory are the following: [Axiom 1] Operations correspond to operators. [Axiom 2] Every complete set of positive operators corresponds to a complete set of operations. The following operational postulates are shown to be equivalent to these mathematical axioms: [P1] Definiteness. Associated with any given pure state is a unique maximal effect giving probability equal to one. This maximal effect does not give probability equal to one for any other pure state. [P2] Information locality. A maximal measurement on a composite system is effected if we perform maximal measurements on each of the components. [P3] Tomographic locality. The state of a composite system can be determined from the statistics collected by making measurements on the components. [P4] Compound permutatability. There exis...

  1. Reconstructing and deconstructing dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Linder, Eric V.

    2004-06-07

    The acceleration of the expansion of the universe, ascribed to a dark energy, is one of the most intriguing discoveries in science. In addition to precise, systematics controlled data, clear, robust interpretation of the observations is required to reveal the nature of dark energy. Even for the simplest question: is the data consistent with the cosmological constant? there are important subtleties in the reconstruction of the dark energy properties. We discuss the roles of analysis both in terms of the Hubble expansion rate or dark energy density {rho}DE(z) and in terms of the dark energy equation of state w(z), arguing that each has its carefully defined place. Fitting the density is best for learning about the density, but using it to probe the equation of state can lead to instability and bias.

  2. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1991-01-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Pacific Northwest Laboratory (PNL) under the direction of an independent Technical Steering Panel (TSP). The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed technical members representing the states of Oregon and Washington, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on human (dose estimates): Source Terms; Environmental Transport; Environmental Monitoring Data; Demographics, Agriculture, Food Habits and; Environmental Pathways and Dose Estimates.

  3. Inverse imbalance reconstruction in rotordynamics

    Energy Technology Data Exchange (ETDEWEB)

    Ramlau, R. [Austrian Academy of Sciences, Linz (Austria). Johann Radon Inst. for Computational and Applied Mathematics; Dicken, V. [MeVis GmbH, Bremen (Germany); Maass, P. [Bremen Univ. (Germany). Zentrum fuer Technomathematik; Streller, C. [Rolls-Royce Germany GmbH, Dahlewitz (Germany); Rienaecker, A. [MTU Aero Engines GmbH, Muenchen (Germany)

    2006-05-15

    The goal of this work is to establish and compare algorithms for inverse imbalance reconstruction in aircraft turbines. Such algorithms are based on a validated whole engine model of a turbo engine under consideration. Base on the model, the impact of an imbalance distribution on the vibration behaviour of the turbine can be described as a matrix-vector multiplication Af = g, where f is the imbalance distribution and g the vibration response. It turns out that the matrix A is very ill-conditioned. As the measured data is highly affected with noise, we have to use regularization methods in order to stabilize the inversion. Our main interest was in the use of nonlinear regularization methods, in particular nonlinear filtered singular value decomposition and conjugate gradient regularization. (orig.)

  4. One-shot 3d surface reconstruction from instantaneous frequencies: solutions to ambiguity problems

    NARCIS (Netherlands)

    Heijden, van der F.; Spreeuwers, L.J.; Nijmeijer, A.C.

    2009-01-01

    Phase-measuring profilometry is a well known technique for 3D surface reconstruction based on a sinusoidal pattern that is projected on a scene. If the surface is partly occluded by, for instance, other objects, then the depth shows abrupt transitions at the edges of these occlusions. This causes am

  5. Reversible wurtzite-tetragonal reconstruction in ZnO(1010) surfaces.

    Science.gov (United States)

    He, Mo-Rigen; Yu, Rong; Zhu, Jing

    2012-07-27

    Bistable surface: The reversible phase transition between wurtzite (WZ) and body-centered-tetragonal (BCT) lattice was activated in ZnO(1010) surfaces and directly imaged at atomic scale by using aberration-corrected electron microscopy. A nucleation-growth mechanism for the surface reconstruction is further proposed based on observations and calculations of the WZ-BCT domain boundary.

  6. Phase-sensitive fat suppression steady-state free procession sequence with phase correction

    Institute of Scientific and Technical Information of China (English)

    Zu Zhong-Liang; Zhou Kun; Zhang Shi-Gang; Gao Song; Bao Shang-Lian

    2008-01-01

    Robust and fast fat suppression is a challenge in balanced steady-state free precession (SSFP) magnetic resonance imaging.Although single-acquisition phase-sensitive SSFP can provide fat-suppressed images in short scan time,phase errors,especially spatially-dependent phase shift,caused by a variety of factors may result in misplacement of fat and water voxels.In this paper,a novel phase correction algorithm was used to calibrate those phase errors during image reconstruction.This algorithm corrects phase by region growing,employing both the magnitude and the phase information of image pixels.Phantom and in vivo imagings were performed to validate the technique.As a result,excellent fat-suppressed images were acquired by using single-acquisition phase-seusitive SSFP with phase correction.

  7. Digital reconstruction of optically-induced potentials.

    Science.gov (United States)

    Barsi, Christopher; Fleischer, Jason W

    2009-12-01

    The holographic reconstruction of optically-induced objects typically assumes that the object is axially thin. Here, we demonstrate a simple approach that works for axially thick objects which evolve dynamically. Results are verified by reconstructing linear scattering experiments in a self-defocusing photorefractive crystal.

  8. Exploring the topology of dynamical reconstructions

    Science.gov (United States)

    Garland, Joshua; Bradley, Elizabeth; Meiss, James D.

    2016-11-01

    Computing the state-space topology of a dynamical system from scalar data requires accurate reconstruction of those dynamics and construction of an appropriate simplicial complex from the results. The reconstruction process involves a number of free parameters and the computation of homology for a large number of simplices can be expensive. This paper is a study of how to compute the homology efficiently and effectively without a full (diffeomorphic) reconstruction. Using trajectories from the classic Lorenz system, we reconstruct the dynamics using the method of delays, then build a simplicial complex whose vertices are a small subset of the data: the "witness complex". Surprisingly, we find that the witness complex correctly resolves the homology of the underlying invariant set from noisy samples of that set even if the reconstruction dimension is well below the thresholds for assuring topological conjugacy between the true and reconstructed dynamics that are specified in the embedding theorems. We conjecture that this is because the requirements for reconstructing homology are less stringent: a homeomorphism is sufficient-as opposed to a diffeomorphism, as is necessary for the full dynamics. We provide preliminary evidence that a homeomorphism, in the form of a delay-coordinate reconstruction map, may exist at a lower dimension than that required to achieve an embedding.

  9. Microtia reconstruction: autologous rib and alloplast techniques.

    Science.gov (United States)

    Cabin, Jonathan A; Bassiri-Tehrani, Michael; Sclafani, Anthony P; Romo, Thomas

    2014-11-01

    Microtia represents a spectrum of maldevelopment of the external ear. Reconstructive techniques may utilize an autogenous rib cartilage framework and require 2-4 stages; alternatively, an alloplastic framework can be used and typically requires 1-2 stages. Successful reconstruction of microtia with either technique can provide a significant quality of life improvement, and both techniques are described in this article.

  10. Anatomic Double-bundle ACL Reconstruction

    NARCIS (Netherlands)

    V.M. Schreiber; C.F. van Eck; F.H. Fu

    2010-01-01

    Rupture of the anterior cruciate ligament (ACL) is one of the most frequent forms of knee trauma. The traditional surgical treatment for ACL rupture is single-bundle reconstruction. However, during the past few years there has been a shift in interest toward double-bundle reconstruction to closely r

  11. Visions of Reconstruction: Layers of Moving Images

    NARCIS (Netherlands)

    Paalman, Floris Jan Willem

    2015-01-01

    abstractAfter WWII, films accompanied the reconstruction of Europe’s destroyed cities. Many contained historical footage. How was this material used, to articulate visions of reconstruction, what happened to the material later on, and how do the films relate to municipal film archives? This question

  12. Labral reconstruction: when to perform and how

    Directory of Open Access Journals (Sweden)

    Brian J White

    2015-07-01

    Full Text Available Over the past decade, the understanding of the anatomy and function of the hip joint has continuously evolved, and surgical treatment options for the hip have significantly progressed. Originally, surgical treatment of the hip primarily involved resection of damaged tissue. Procedures that maintain and preserve proper hip anatomy, such as labral repair and femoroacetabular impingement (FAI correction, have shown superior results, in terms of pain reduction, increased function, and ability to return to activities. Labral reconstruction is a treatment option that uses a graft to reconstruct the native labrum. The technique and outcomes of labral reconstruction have been described relatively recently, and labral reconstruction is a cutting edge procedure that has shown promising early outcomes. The aim of this article is to review the current literature on hip labral reconstruction. We will review the indications for labral reconstruction, surgical technique and graft options, and surgical outcomes that have been described to date. Labral reconstruction provides an alternative treatment option for challenging intra-articular hip problems. Labral reconstruction restores the original anatomy of the hip and has the potential to preserve the longevity of the hip joint. This technique is an important tool in the orthopaedic surgeon’s arsenal for hip joint treatment and preservation.

  13. Advances in bioprinting technologies for craniofacial reconstruction

    NARCIS (Netherlands)

    Visscher, D.O.; Farré-Guasch, E.; Helder, M.N.; Gibbs, S.; Forouzanfar, T.; van Zuijlen, P.P.; Wolff, J.

    2016-01-01

    Recent developments in craniofacial reconstruction have shown important advances in both the materials and methods used. While autogenous tissue is still considered to be the gold standard for these reconstructions, the harvesting procedure remains tedious and in many cases causes significant donor

  14. Proximal Gastrojejunal Reconstruction after Pancreaticoduodenal Resection

    Directory of Open Access Journals (Sweden)

    M. Wayne

    2012-01-01

    Full Text Available Introduction. Reconstruction by proximal gastrojejunostomy, and distal biliary and pancreatic anastomoses is infrequently used after resection of the head of the pancreas because of fear of fistulas and cholangitis. Pancreaticoduodenectomy is being performed more frequently for cystic malignant and premalignant lesions. Because of this there is a need for endoscopic visualization and biopsy of the residual pancreatic duct, since multi-centricity is characteristic of some of these malignancies. Since endoscopic access of the bile duct and pancreatic duct is difficult and unsuccessful in 50–70% after B II or Roux Y reconstruction, we prospectively studied the merit and complications (early and late of proximal gastrojejunal (PGJ reconstruction after pancreaticoduodenal resection. Material and Methods. Thirty nine consecutive, non-radomized patients underwent pancreaticoduodenectomy and PGJ reconstruction over 14 mos. There were 21 males and 18 females. Results. 7 patients with IPMN have undergone repeat CT scanning for surveillance, with 3 requiring repeat EUS and ERCP. There were no technical difficulties accessing the pancreas or the pancreatic duct, supporting the PGJ reconstruction. Conclusion. Proximal gastrojejunal reconstruction following pancreaticoduodenal resection may be safely done with similar morbidity to traditional pancreaticojejunal reconstructions. PGJ reconstruction may be of greater value when direct visual access to the bile duct or pancreatic duct is necessary, and should be considered when doing resection for mucinous cysts or IPMN of the head of the pancreas.

  15. A Pilot Evaluation of a 4-Dimensional Cone-Beam Computed Tomographic Scheme Based on Simultaneous Motion Estimation and Image Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Jun; Gu, Xuejun [Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, Texas (United States); Pan, Tinsu [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wang, Jing, E-mail: jing.wang@utsouthwestern.edu [Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, Texas (United States)

    2015-02-01

    Purpose: To evaluate the performance of a 4-dimensional (4-D) cone-beam computed tomographic (CBCT) reconstruction scheme based on simultaneous motion estimation and image reconstruction (SMEIR) through patient studies. Methods and Materials: The SMEIR algorithm contains 2 alternating steps: (1) motion-compensated CBCT reconstruction using projections from all phases to reconstruct a reference phase 4D-CBCT by explicitly considering the motion models between each different phase and (2) estimation of motion models directly from projections by matching the measured projections to the forward projection of the deformed reference phase 4D-CBCT. Four lung cancer patients were scanned for 4 to 6 minutes to obtain approximately 2000 projections for each patient. To evaluate the performance of the SMEIR algorithm on a conventional 1-minute CBCT scan, the number of projections at each phase was reduced by a factor of 5, 8, or 10 for each patient. Then, 4D-CBCTs were reconstructed from the down-sampled projections using Feldkamp-Davis-Kress, total variation (TV) minimization, prior image constrained compressive sensing (PICCS), and SMEIR. Using the 4D-CBCT reconstructed from the fully sampled projections as a reference, the relative error (RE) of reconstructed images, root mean square error (RMSE), and maximum error (MaxE) of estimated tumor positions were analyzed to quantify the performance of the SMEIR algorithm. Results: The SMEIR algorithm can achieve results consistent with the reference 4D-CBCT reconstructed with many more projections per phase. With an average of 30 to 40 projections per phase, the MaxE in tumor position detection is less than 1 mm in SMEIR for all 4 patients. Conclusion: The results from a limited number of patients show that SMEIR is a promising tool for high-quality 4D-CBCT reconstruction and tumor motion modeling.

  16. Lensing Reconstruction using redshifted 21cm Fluctuations

    CERN Document Server

    Zahn, O; Zahn, Oliver; Zaldarriaga, Matias

    2005-01-01

    We investigate the potential of second generation measurements of redshifted 21 cm radiation from the epoch of reionization (EOR) to reconstruct the matter density fluctuations along the line of sight. To do so we generalize the quadratic methods developed for the Cosmic Microwave Background (CMB) to 21cm fluctuations. The three dimensional signal can be analyzed into a finite number of line of sight Fourier modes that contribute to the lensing reconstruction. In comparison with reconstruction using the CMB, 21cm fluctuations have a disadvantage of relative featurelessness, which can be compensated for by the fact that there are multiple uncorrelated backgrounds. The multiple redshift information allows to reconstruct relatively small scales even if one is limited by angular resolution. We estimate that a square kilometer of collecting area is needed with a maximal baseline of 3 km to achieve lensing reconstruction noise levels an order of magnitude below CMB quadratic estimator constraints at $l=1000$, and c...

  17. Track reconstruction in CMS high luminosity environment

    CERN Document Server

    Sguazzoni, Giacomo

    2014-01-01

    The CMS tracker is the largest silicon detector ever built, covering 200 square meters and providing an average of 14 high-precision measurements per track. Tracking is essential for the reconstruction of objects like jets, muons, electrons and tau leptons starting from the raw data from the silicon pixel and strip detectors. Track reconstruction is widely used also at trigger level as it improves objects tagging and resolution.The CMS tracking code is organized in several levels, known as iterative steps, each optimized to reconstruct a class of particle trajectories, as the ones of particles originating from the primary vertex or displaced tracks from particles resulting from secondary vertices. Each iterative step consists of seeding, pattern recognition and fitting by a kalman filter, and a final filtering and cleaning. Each subsequent step works on hits not yet associated to a reconstructed particle trajectory.The CMS tracking code is continuously evolving to make the reconstruction computing load compat...

  18. Electronic noise modeling in statistical iterative reconstruction.

    Science.gov (United States)

    Xu, Jingyan; Tsui, Benjamin M W

    2009-06-01

    We consider electronic noise modeling in tomographic image reconstruction when the measured signal is the sum of a Gaussian distributed electronic noise component and another random variable whose log-likelihood function satisfies a certain linearity condition. Examples of such likelihood functions include the Poisson distribution and an exponential dispersion (ED) model that can approximate the signal statistics in integration mode X-ray detectors. We formulate the image reconstruction problem as a maximum-likelihood estimation problem. Using an expectation-maximization approach, we demonstrate that a reconstruction algorithm can be obtained following a simple substitution rule from the one previously derived without electronic noise considerations. To illustrate the applicability of the substitution rule, we present examples of a fully iterative reconstruction algorithm and a sinogram smoothing algorithm both in transmission CT reconstruction when the measured signal contains additive electronic noise. Our simulation studies show the potential usefulness of accurate electronic noise modeling in low-dose CT applications.

  19. Modeling the reconstructed BAO in Fourier space

    CERN Document Server

    Seo, Hee-Jong; Ross, Ashley J; Saito, Shun

    2015-01-01

    The density field reconstruction technique, which was developed to partially reverse the nonlinear degradation of the Baryon Acoustic Oscillation (BAO) feature in the galaxy redshift surveys, has been successful in substantially improving the cosmology constraints from recent galaxy surveys such as Baryon Oscillation Spectroscopic Survey (BOSS). We estimate the efficiency of the reconstruction method as a function of various reconstruction details. To directly quantify the BAO information in nonlinear density fields before and after reconstruction, we calculate the cross-correlations (i.e., propagators) of the pre(post)-reconstructed density field with the initial linear field using a mock galaxy sample that is designed to mimic the clustering of the BOSS CMASS galaxies. The results directly provide the BAO damping as a function of wavenumber that can be implemented into the Fisher matrix analysis. We focus on investigating the dependence of the propagator on a choice of smoothing filters and on two major dif...

  20. Bayesian image reconstruction: Application to emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, J.; Llacer, J.

    1989-02-01

    In this paper we propose a Maximum a Posteriori (MAP) method of image reconstruction in the Bayesian framework for the Poisson noise case. We use entropy to define the prior probability and likelihood to define the conditional probability. The method uses sharpness parameters which can be theoretically computed or adjusted, allowing us to obtain MAP reconstructions without the problem of the grey'' reconstructions associated with the pre Bayesian reconstructions. We have developed several ways to solve the reconstruction problem and propose a new iterative algorithm which is stable, maintains positivity and converges to feasible images faster than the Maximum Likelihood Estimate method. We have successfully applied the new method to the case of Emission Tomography, both with simulated and real data. 41 refs., 4 figs., 1 tab.

  1. Innovations in diabetic foot reconstruction using supermicrosurgery.

    Science.gov (United States)

    Suh, Hyun Suk; Oh, Tae Suk; Hong, Joon Pio

    2016-01-01

    The treatment of diabetic foot ulceration is complex with multiple factors involved, and it may often lead to limb amputation. Hence, a multidisciplinary approach is warranted to cover the spectrum of treatment for diabetic foot, but in complex wounds, surgical treatment is inevitable. Surgery may involve the decision to preserve the limb by reconstruction or to amputate it. Reconstruction involves preserving the limb with secure coverage. Local flaps usually are able to provide sufficient coverage for small or moderate sized wound, but for larger wounds, soft tissue coverage involves flaps that are distantly located from the wound. Reconstruction of distant flap usually involves microsurgery, and now, further innovative methods such as supermicrosurgery have further given complex wounds a better chance to be reconstructed and limbs salvaged. This article reviews the microsurgery involved in reconstruction and introduces the new method of supermicrosurgery.

  2. Discrete algebraic reconstruction technique: a new approach for superresolution reconstruction of license plates

    Science.gov (United States)

    Zarei Zefreh, Karim; van Aarle, Wim; Batenburg, K. Joost; Sijbers, Jan

    2013-10-01

    A new superresolution algorithm is proposed to reconstruct a high-resolution license plate image from a set of low-resolution camera images. The reconstruction methodology is based on the discrete algebraic reconstruction technique (DART), a recently developed reconstruction method. While DART has already been successfully applied in tomographic imaging, it has not yet been transferred to the field of camera imaging. DART is introduced for camera imaging through a demonstration of how prior knowledge of the colors of the license plate can be directly exploited during the reconstruction of a high-resolution image from a set of low-resolution images. Simulation experiments show that DART can reconstruct images with superior quality compared to conventional reconstruction methods.

  3. Binding by asynchrony: the neuronal phase code

    Directory of Open Access Journals (Sweden)

    Zoltan Nadasdy

    2010-09-01

    Full Text Available Neurons display continuous subthreshold oscillations and discrete action potentials. When action potentials are phase-locked to the subthreshold oscillation, we hypothesize they represent two types of information: the presence/absence of a sensory feature and the phase of subthreshold oscillation. If subthreshold oscillation phases are neuron-specific, then the sources of action potentials can be recovered based on the action potential times. If the spatial information about the stimulus is converted to action potential phases, then action potentials from multiple neurons can be combined into a single axon and the spatial configuration reconstructed elsewhere. For the reconstruction to be successful, we introduce two assumptions: that a subthreshold oscillation field has a constant phase gradient and that coincidences between action potentials and intracellular subthreshold oscillations are neuron-specific as defined by the "interference principle." Under these assumptions, a phase coding model enables information transfer between structures and reproduces experimental phenomenons such as phase precession, grid cell architecture, and phase modulation of cortical spikes. This article reviews a recently proposed neuronal algorithm for information encoding and decoding from the phase of action potentials (Nadasdy 2009. The focus is given to the principles common across different systems instead of emphasizing system specific differences.

  4. Spin density wave order, topological order, and Fermi surface reconstruction

    CERN Document Server

    Sachdev, Subir; Chatterjee, Shubhayu; Schattner, Yoni

    2016-01-01

    In the conventional theory of density wave ordering in metals, the onset of spin density wave (SDW) order co-incides with the reconstruction of the Fermi surfaces into small 'pockets'. We present models which display this transition, while also displaying an alternative route between these phases via an intermediate phase with topological order, no broken symmetry, and pocket Fermi surfaces. The models involve coupling emergent gauge fields to a fractionalized SDW order, but retain the canonical electron operator in the underlying Hamiltonian. We establish an intimate connection between the suppression of certain defects in the SDW order, and the presence of Fermi surface sizes distinct from the Luttinger value in Fermi liquids. We discuss the relevance of such models to the physics of the hole-doped cuprates near optimal doping.

  5. An improved image reconstruction method for optical intensity correlation Imaging

    Science.gov (United States)

    Gao, Xin; Feng, Lingjie; Li, Xiyu

    2016-12-01

    The intensity correlation imaging method is a novel kind of interference imaging and it has favorable prospects in deep space recognition. However, restricted by the low detecting signal-to-noise ratio (SNR), it's usually very difficult to obtain high-quality image of deep space object like high-Earth-orbit (HEO) satellite with existing phase retrieval methods. In this paper, based on the priori intensity statistical distribution model of the object and characteristics of measurement noise distribution, an improved method of Prior Information Optimization (PIO) is proposed to reduce the ambiguous images and accelerate the phase retrieval procedure thus realizing fine image reconstruction. As the simulations and experiments show, compared to previous methods, our method could acquire higher-resolution images with less error in low SNR condition.

  6. Using the GRAPPA operator and the generalized sampling theorem to reconstruct undersampled non-Cartesian data.

    Science.gov (United States)

    Seiberlich, Nicole; Breuer, Felix A; Ehses, Philipp; Moriguchi, Hisamoto; Blaimer, Martin; Jakob, Peter M; Griswold, Mark A

    2009-03-01

    As expected from the generalized sampling theorem of Papoulis, the use of a bunched sampling acquisition scheme in conjunction with a conjugate gradient (CG) reconstruction algorithm can decrease scan time by reducing the number of phase-encoding lines needed to generate an unaliased image at a given resolution. However, the acquisition of such bunched data requires both modified pulse sequences and high gradient performance. A novel method of generating the "bunched" data using self-calibrating GRAPPA operator gridding (GROG), a parallel imaging method that shifts data points by small distances in k-space (with Deltak usually less than 1.0, depending on the receiver coil) using the GRAPPA operator, is presented here. With the CG reconstruction method, these additional "bunched" points can then be used to reconstruct an image with reduced artifacts from undersampled data. This method is referred to as GROG-facilitated bunched phase encoding (BPE), or GROG-BPE. To better understand how the patterns of bunched points, maximal blip size, and number of bunched points affect the reconstruction quality, a number of simulations were performed using the GROG-BPE approach. Finally, to demonstrate that this method can be combined with a variety of trajectories, examples of images with reduced artifacts reconstructed from undersampled in vivo radial, spiral, and rosette data are shown.

  7. Biomechanical comparison of posterior cruciate ligament reconstruction techniques using cyclic loading tests.

    Science.gov (United States)

    Hiraga, Yasuharu; Ishibashi, Yasuyuki; Tsuda, Eiichi; Toh, Harehiko Tsukada Satoshi

    2006-01-01

    Posterior tibial translation (PTT) of the posterior cruciate ligament (PCL) reconstructed-knee under cyclic loading of 1,000 cycles with a 100-N load was compared between four different procedures, including two reconstructions with patellar tendon graft (transtunnel and inlay techniques) and two reconstructions with hamstring tendon graft (Endobutton and EndoPearl techniques) in twelve fresh-frozen human knees. The EndoPearl technique is a direct tendon fixation using biodegradable interference screws and an anchoring device, while the Endobutton technique is an indirect tendon fixation using a titanium button and surgical tape. The change of PTT after cyclic loading in the Endobutton technique was significantly greater than in the other reconstruction technique. No graft rupture at the killer turn or complete pullout from the bone tunnel was found. The advantage of the inlay technique compared to the transtunnel technique with respect to the posterior stability could not be shown in the current study. Posterior laxity of PCL reconstructed-knees with hamstring tendon graft using the Endobutton technique increased more easily than that with patellar tendon graft. For PCL reconstruction using the hamstring tendon graft, anatomical fixation may be preferable to prevent excessive posterior laxity in the early phase of the rehabilitation protocol.

  8. Reconstruction of 3-D Temperature Field in Holographic Interferometry

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The tomography technique is commonly used for the reconstruction of holographic interferometry. However, the current reconstruction method doesn't consider the measurement errors which are non-avoidable in the measurement and will degrade the reconstruction quality. The factors affecting the reconstruction quality are analyzed and the distribution law of the reconstruction error with experimental errors is discussed. Finally, a method to improve the reconstruction quality—the Kalman filter method is presented.

  9. Computer-Assisted Surgery for Segmental Mandibular Reconstruction with the Osteoseptocutaneous Fibula Flap: Can We Instigate Ideological and Technological Reforms?

    Science.gov (United States)

    Deek, Nidal Farhan A L; Wei, Fu-Chan

    2016-03-01

    Virtual surgical planning and computer-aided design and computer-aided modeling are promising technologies with a growing trend in contemporary head and neck reconstruction. Segmental mandibular reconstruction with the osteoseptocutaneous fibula flap is one of the fields in which these technologies are increasingly used. Perceived benefits are increased surgical precision, improved operative efficiency, and overall good outcomes. Nevertheless, these programs do not cover the reconstruction picture of interest thoroughly, at least in the mind of the experienced surgeon. Based on extensive experience in segmental mandibular reconstruction and comprehensive literature review, the authors attempted to identify missing dots in computer-aided mandibular reconstruction; when possible, a problem-solution approach was taken. Of these dots, pedicle reach to the recipient vessels, multiple target soft-tissue reconstruction, anatomical variations and cross-section topography of the osteoseptocutaneous fibula flap, and intraoperative modification of the surgical plan were understated or not considered in the phases of virtual surgical planning and execution. Moreover, with the relatively small experience reported in computer-aided segmental mandibular reconstruction compared with the well-appreciated challenges, further discussion of what could be a realistic and safe indication was deemed necessary. Following in the footsteps of the iPhone developer of creating software satisfying to customers (i.e., surgeons) first and armed with the evidence from the literature and accumulation of experience, this Special Topic article aims to provoke a discussion among experts in this field to instigate ideological and technological reforms in computer-aided mandibular reconstruction.

  10. CONCEPT OF TISSUE EXPANSION IN RECONSTRUCTIVE SURGERY

    Directory of Open Access Journals (Sweden)

    Sheeja Rajan

    2015-01-01

    Full Text Available BACKGROUND: Tissue expansion is a unique reconstructive option in the armamentarium of a reconstructive surgeon whereby skin and soft tissues of our body can be stretched to large dimensions for wound coverage. The basis for such stretch ability lies in the inherent viscoelastic properties of skin. AIMS: This paper explores the prospects of using tissue expanders to reconstruct defects arising due to a kaleidoscope of pathological conditions including burns scars, post traumatic scars, congenital anomalies like hairy nevus, involutional scars in haemangioma as well as in post mastectomy breast reconstruction . MATERIALS AND METHODS: Our experience with tissue expansion in 14 patients over 24 months is presented. Tissue expanders made of silicone in sizes from 100 - 250ml, of round, rectangular or croissant (crescent shapes have been used. Areas expanded include scalp, forehead, neck, abdomen and forearm. Multiple expanders have been used when possible. Average expansion time was 8 - 12 weeks and the expanded tissue was transferred as advancement flaps. RESULTS AND CONCLUSIONS: Tissue expansion was successfully completed in 13 patients. Expansion had to be aborted in 1 paediatric patient undergoing neck expansion due to infection. Implant failure occurred in 1 patient during serial expansion. Nevertheless, in our experience tissue expan sion is an invaluable reconstructive tool to give excellent donor tissue with colour and texture match in countless situations demanding aesthetic and functional reconstruction. KEYWORDS: Burns scars, Reconstruction, Tissue expansion .

  11. Live ultrasound volume reconstruction using scout scanning

    Science.gov (United States)

    Meyer, Amelie; Lasso, Andras; Ungi, Tamas; Fichtinger, Gabor

    2015-03-01

    Ultrasound-guided interventions often necessitate scanning of deep-seated anatomical structures that may be hard to visualize. Visualization can be improved using reconstructed 3D ultrasound volumes. High-resolution 3D reconstruction of a large area during clinical interventions is challenging if the region of interest is unknown. We propose a two-stage scanning method allowing the user to perform quick low-resolution scouting followed by high-resolution live volume reconstruction. Scout scanning is accomplished by stacking 2D tracked ultrasound images into a low-resolution volume. Then, within a region of interest defined in the scout scan, live volume reconstruction can be performed by continuous scanning until sufficient image density is achieved. We implemented the workflow as a module of the open-source 3D Slicer application, within the SlicerIGT extension and building on the PLUS toolkit. Scout scanning is performed in a few seconds using 3 mm spacing to allow region of interest definition. Live reconstruction parameters are set to provide good image quality (0.5 mm spacing, hole filling enabled) and feedback is given during live scanning by regularly updated display of the reconstructed volume. Use of scout scanning may allow the physician to identify anatomical structures. Subsequent live volume reconstruction in a region of interest may assist in procedures such as targeting needle interventions or estimating brain shift during surgery.

  12. Inverse problem approaches for digital hologram reconstruction

    Science.gov (United States)

    Fournier, Corinne; Denis, Loic; Thiebaut, Eric; Fournel, Thierry; Seifi, Mozhdeh

    2011-06-01

    Digital holography (DH) is being increasingly used for its time-resolved three-dimensional (3-D) imaging capabilities. A 3-D volume can be numerically reconstructed from a single 2-D hologram. Applications of DH range from experimental mechanics, biology, and fluid dynamics. Improvement and characterization of the 3-D reconstruction algorithms is a current issue. Over the past decade, numerous algorithms for the analysis of holograms have been proposed. They are mostly based on a common approach to hologram processing: digital reconstruction based on the simulation of hologram diffraction. They suffer from artifacts intrinsic to holography: twin-image contamination of the reconstructed images, image distortions for objects located close to the hologram borders. The analysis of the reconstructed planes is therefore limited by these defects. In contrast to this approach, the inverse problems perspective does not transform the hologram but performs object detection and location by matching a model of the hologram. Information is thus extracted from the hologram in an optimal way, leading to two essential results: an improvement of the axial accuracy and the capability to extend the reconstructed field beyond the physical limit of the sensor size (out-of-field reconstruction). These improvements come at the cost of an increase of the computational load compared to (typically non iterative) classical approaches.

  13. Functional reconstruction following brachial plexus root avulsion

    Institute of Scientific and Technical Information of China (English)

    Guixin Sun; Cunyi Fan; Yudong Gu

    2007-01-01

    OBJECTIVE: To sum up the treatment of brachial plexus root avulsion and the progress in functional reconstruction and rehabilitation following brachial plexus root avulsion.DATA SOURCES: A search of Medline was performed to select functional reconstruction and rehabilitation following brachial plexus injury-related English articles published between January 1990 and July 2006, with key words of "brachial plexus injury, reconstruction and rehabilitation". Meanwhile, a computer-based search of CBM was carried out to select the similar Chinese articles published between January 1998 and July 2006,with key words of "brachial plexus injury, reconstruction and rehabilitation".STUDY SELECTION: The materials were checked primarily, and the literatures of functional reconstruction and rehabilitation of brachial plexus injury were selected and the full texts were retrieved.Inclusive criteria: ① Functional reconstruction following brachial plexus injury. ② Rehabilitation method of brachial plexus injury. Exclusive criteria: Reviews, repetitive study, and Meta analytical papers.DATA EXTRACTION: Forty-six literatures about functional reconstruction following brachial plexus injury were collected, and 36 of them met the inclusive criteria.DATA SYNTHESIS: Brachial plexus injury causes the complete or incomplete palsy of muscle of upper extremity. The treatment of brachial plexus is to displace not very important nerves to the distal end of very important nerve, called nerve transfer, which is an important method to treat brachial plexus injury.Postoperative rehabilitations consist of sensory training and motor functional training. It is very important to keep the initiativeness of exercise. Besides recovering peripheral nerve continuity by operation, combined treatment and accelerating neural regeneration, active motors of cerebral cortex is also the important factor to reconstruct peripheral nerve function.CONCLUSION: Consciously and actively strengthening functional

  14. Accurate modeling and reconstruction of three-dimensional percolating filamentary microstructures from two-dimensional micrographs via dilation-erosion method

    Energy Technology Data Exchange (ETDEWEB)

    Guo, En-Yu [Key Laboratory for Advanced Materials Processing Technology, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Materials Science and Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287 (United States); Chawla, Nikhilesh [Materials Science and Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287 (United States); Jing, Tao [Key Laboratory for Advanced Materials Processing Technology, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Torquato, Salvatore [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States); Department of Physics, Princeton University, Princeton, NJ 08544 (United States); Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, NJ 08544 (United States); Program in Applied and Computational Mathematics, Princeton University, Princeton, NJ 08544 (United States); Jiao, Yang, E-mail: yang.jiao.2@asu.edu [Materials Science and Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287 (United States)

    2014-03-01

    Heterogeneous materials are ubiquitous in nature and synthetic situations and have a wide range of important engineering applications. Accurate modeling and reconstructing three-dimensional (3D) microstructure of topologically complex materials from limited morphological information such as a two-dimensional (2D) micrograph is crucial to the assessment and prediction of effective material properties and performance under extreme conditions. Here, we extend a recently developed dilation–erosion method and employ the Yeong–Torquato stochastic reconstruction procedure to model and generate 3D austenitic–ferritic cast duplex stainless steel microstructure containing percolating filamentary ferrite phase from 2D optical micrographs of the material sample. Specifically, the ferrite phase is dilated to produce a modified target 2D microstructure and the resulting 3D reconstruction is eroded to recover the percolating ferrite filaments. The dilation–erosion reconstruction is compared with the actual 3D microstructure, obtained from serial sectioning (polishing), as well as the standard stochastic reconstructions incorporating topological connectedness information. The fact that the former can achieve the same level of accuracy as the latter suggests that the dilation–erosion procedure is tantamount to incorporating appreciably more topological and geometrical information into the reconstruction while being much more computationally efficient. - Highlights: • Spatial correlation functions used to characterize filamentary ferrite phase • Clustering information assessed from 3D experimental structure via serial sectioning • Stochastic reconstruction used to generate 3D virtual structure 2D micrograph • Dilation–erosion method to improve accuracy of 3D reconstruction.

  15. Reconstruction of the Genesis Entry

    Science.gov (United States)

    Desai, Prasun N.; Qualls, Garry D.; Schoenenberger, Mark

    2007-01-01

    An overview of the reconstruction analyses performed for the Genesis capsule entry is described. The results indicate that the actual entry prior to the drogue deployment failure was very close to the pre-entry predictions. The capsule landed 8.3 km south of the desired target at Utah Test and Training Range. Analysis on infrared video footage (obtained from the tracking stations) during the descent estimated the onset of the capsule tumble at Mach 0.9. Frequency analysis on the infrared video data indicates that the aerodynamics generated for the Genesis capsule reasonably predicted the drag and static stability. Observations of the heatshield support the pre-entry simulation estimates of a small hypersonic angles-of-attack, since there is very little, if any, charring of the shoulder region or the aftbody. Through this investigation, an overall assertion can be made that all the data gathered from the Genesis entry is consistent with flight performance that was close to the nominal preentry prediction. Consequently, the design principles and methodologies utilized for the flight dynamics, aerodynamics, and aerothermodynamics analyses have been corroborated.

  16. Carboniferous paleogeographic and paleoclimatic reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Scotese, C.R. (Univ. of Texas, Arlington, TX (United States). Dept. of Geology); Raymond, A. (Texas A and M Univ., College Station, TX (United States). Dept. Geology)

    1992-01-01

    The Carboniferous was an important transitional period in earth history. The Paleozoic oceans separating the continents of Gondwana, Laurentia, Baltica, Kazakhstan, and Siberia had closed by the late Carboniferous forming the late Paleozoic supercontinent of Pangea. Plate motions which appear to have been rapid during the Early Carboniferous (6--10 cm/yr), slowed to a temperature gradient increased as the Earth's climate changed from hot-house to ice-house conditions. Sea level, which stood high during the Early Carboniferous, fell as a result of continental collision and mountain-building, and then began to rise and fall rhythmically as the South Polar ice-cap waxed and waned. These environmental changes intersected important evolutionary events, namely, the explosive colonization of the emergent land areas by plants and the rise of terrestrial vertebrates. In this paper the authors present paleogeographic reconstructions for 6 intervals during the Carboniferous. These maps illustrate the latitudinal position of the continents deduced from paleomagnetic data and the distribution of climatically restricted lithofacies (coal, bauxite, evaporite, calcrete, and tillite), the inferred location of active plate boundaries, and the changing configuration of mountains, land, shallow seas, and deep ocean basins. For each of these paleogeographic maps a climatic simulation was run using the Parametric Climate Model. These simulations predict the distribution of high and low pressure cells, prevailing wind directions, pole-to-equator temperature gradient, relative wetness/dryness, as well as zones of coastal upwelling.

  17. Advances in thermographic signal reconstruction

    Science.gov (United States)

    Shepard, Steven M.; Frendberg Beemer, Maria

    2015-05-01

    Since its introduction in 2001, the Thermographic Signal Reconstruction (TSR) method has emerged as one of the most widely used methods for enhancement and analysis of thermographic sequences, with applications extending beyond industrial NDT into biomedical research, art restoration and botany. The basic TSR process, in which a noise reduced replica of each pixel time history is created, yields improvement over unprocessed image data that is sufficient for many applications. However, examination of the resulting logarithmic time derivatives of each TSR pixel replica provides significant insight into the physical mechanisms underlying the active thermography process. The deterministic and invariant properties of the derivatives have enabled the successful implementation of automated defect recognition and measurement systems. Unlike most approaches to analysis of thermography data, TSR does not depend on flawbackground contrast, so that it can also be applied to characterization and measurement of thermal properties of flaw-free samples. We present a summary of recent advances in TSR, a review of the underlying theory and examples of its implementation.

  18. Reconstructing HST Images of Asteroids

    Science.gov (United States)

    Storrs, A. D.; Bank, S.; Gerhardt, H.; Makhoul, K.

    2003-12-01

    We present reconstructions of images of 22 large main belt asteroids that were observed by Hubble Space Telescope with the Wide-Field/Planetary cameras. All images were restored with the MISTRAL program (Mugnier, Fusco, and Conan 2003) at enhanced spatial resolution. This is possible thanks to the well-studied and stable point spread function (PSF) on HST. We present some modeling of this process and determine that the Strehl ratio for WF/PC (aberrated) images can be improved to 130 ratio of 80 We will report sizes, shapes, and albedos for these objects, as well as any surface features. Images taken with the WFPC-2 instrument were made in a variety of filters so that it should be possible to investigate changes in mineralogy across the surface of the larger asteroids in a manner similar to that done on 4 Vesta by Binzel et al. (1997). Of particular interest are a possible water of hydration feature on 1 Ceres, and the non-observation of a constriction or gap between the components of 216 Kleopatra. Reduction of this data was aided by grant HST-GO-08583.08A from the Space Telescope Science Institute. References: Mugnier, L.M., T. Fusco, and J.-M. Conan, 2003. JOSA A (submitted) Binzel, R.P., Gaffey, M.J., Thomas, P.C., Zellner, B.H., Storrs, A.D., and Wells, E.N. 1997. Icarus 128 pp. 95-103

  19. RECONSTRUCTION STABILITY OF NEARFIELD ACOUSTIC HOLOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    Bi Chuanxing; Chen Xinzhao; Zhou Rong; Chen Jian

    2005-01-01

    The distributed source boundary point method (DSBPM) is used as the spatial transform algorithm for realizing nearfield acoustic holography (NAH), the sensitivity of the reconstructed solution to the measurement errors is analyzed, and the regularization method is proposed to stabilize the reconstruction process, control the influence of the measurement errors and get a better approximate solution. An oscillating sphere is investigated as a numerical example, the influence of the measurement errors on the reconstruction solution is demonstrated, and the feasibility and validity of the regularization method are validated.

  20. Improving analytical tomographic reconstructions through consistency conditions

    CERN Document Server

    Arcadu, Filippo; Stampanoni, Marco; Marone, Federica

    2016-01-01

    This work introduces and characterizes a fast parameterless filter based on the Helgason-Ludwig consistency conditions, used to improve the accuracy of analytical reconstructions of tomographic undersampled datasets. The filter, acting in the Radon domain, extrapolates intermediate projections between those existing. The resulting sinogram, doubled in views, is then reconstructed by a standard analytical method. Experiments with simulated data prove that the peak-signal-to-noise ratio of the results computed by filtered backprojection is improved up to 5-6 dB, if the filter is used prior to reconstruction.

  1. Asymmetry in the reconstructed deceleration parameter

    CERN Document Server

    Bernal, Carla; Motta, Veronica

    2016-01-01

    We study the orientation dependence of the reconstructed deceleration parameter as a function of redshift. We use the Union 2 and Loss datasets, by using the well known preferred axis discussed in the literature, finding the best fit reconstructed deceleration parameter. We found that a low redshift transition of the reconstructed $q(z)$ is clearly absent in one direction and amazingly sharp in the opposite one. We discuss the possibility that such a behavior can be associated with large scale structures affecting the data.

  2. Acoustic imaging for temperature distribution reconstruction

    Science.gov (United States)

    Jia, Ruixi; Xiong, Qingyu; Liang, Shan

    2016-12-01

    For several industrial processes, such as burning and drying, temperature distribution is important because it can reflect the internal running state of industrial equipment and assist to develop control strategy and ensure safety in operation of industrial equipment. The principle of this technique is mainly based on the relationship between acoustic velocity and temperature. In this paper, an algorithm for temperature distribution reconstruction is considered. Compared with reconstruction results of simulation experiments with the least square algorithm and the proposed one, the latter indicates a better information reflection of temperature distribution and relatively higher reconstruction accuracy.

  3. Acoustic imaging for temperature distribution reconstruction

    Directory of Open Access Journals (Sweden)

    Ruixi Jia

    2016-12-01

    Full Text Available For several industrial processes, such as burning and drying, temperature distribution is important because it can reflect the internal running state of industrial equipment and assist to develop control strategy and ensure safety in operation of industrial equipment. The principle of this technique is mainly based on the relationship between acoustic velocity and temperature. In this paper, an algorithm for temperature distribution reconstruction is considered. Compared with reconstruction results of simulation experiments with the least square algorithm and the proposed one, the latter indicates a better information reflection of temperature distribution and relatively higher reconstruction accuracy.

  4. Sparse Image Reconstruction in Computed Tomography

    DEFF Research Database (Denmark)

    Jørgensen, Jakob Sauer

    In recent years, increased focus on the potentially harmful effects of x-ray computed tomography (CT) scans, such as radiation-induced cancer, has motivated research on new low-dose imaging techniques. Sparse image reconstruction methods, as studied for instance in the field of compressed sensing...... and limitations of sparse reconstruction methods in CT, in particular in a quantitative sense. For example, relations between image properties such as contrast, structure and sparsity, tolerable noise levels, suficient sampling levels, the choice of sparse reconstruction formulation and the achievable image...

  5. Maximizing results in reconstruction of cheek defects.

    Science.gov (United States)

    Mureau, Marc A M; Hofer, Stefan O P

    2009-07-01

    The face is exceedingly important, as it is the medium through which individuals interact with the rest of society. Reconstruction of cheek defects after trauma or surgery is a continuing challenge for surgeons who wish to reliably restore facial function and appearance. Important in aesthetic facial reconstruction are the aesthetic unit principles, by which the face can be divided in central facial units (nose, lips, eyelids) and peripheral facial units (cheeks, forehead, chin). This article summarizes established options for reconstruction of cheek defects and provides an overview of several modifications as well as tips and tricks to avoid complications and maximize aesthetic results.

  6. Reconstruction of convex bodies from surface tensors

    DEFF Research Database (Denmark)

    Kousholt, Astrid; Kiderlen, Markus

    2016-01-01

    We present two algorithms for reconstruction of the shape of convex bodies in the two-dimensional Euclidean space. The first reconstruction algorithm requires knowledge of the exact surface tensors of a convex body up to rank s for some natural number s. When only measurements subject to noise...... of surface tensors are available for reconstruction, we recommend to use certain values of the surface tensors, namely harmonic intrinsic volumes instead of the surface tensors evaluated at the standard basis. The second algorithm we present is based on harmonic intrinsic volumes and allows for noisy...

  7. RECONSTRUCTING WOMANHOOD IN TONY MORRISON'S BELOVED

    Directory of Open Access Journals (Sweden)

    Setefanus Suprajitno

    2000-01-01

    Full Text Available Tony Morrison's fifth novel, Beloved (1987, explores the degradation of slavery imposed upon slaves, even when they were owned by a "humane" slave master. The novel is set in the Reconstruction period, the period after the American civil war. The word reconstruction may be used for the Afro-Americans, especially for the Afro-American women who face double discrimination for being black and women. In dealing with women's oppression, Afro-American women have to reconstruct themselves as an act of survival, and to be aware of the horrors of the experiences which their ancestors had to go through.

  8. Reconstruction and Reinvention in Quantum Theory

    Science.gov (United States)

    Dickson, Michael

    2015-10-01

    I consider the fact that there are a number of interesting ways to `reconstruct' quantum theory, and suggest that, very broadly speaking, a form of `instrumentalism' makes good sense of the situation. This view runs against some common wisdom, which dismisses instrumentalism as `cheap'. In contrast, I consider how an instrumentalist might think about the reconstruction theorems, and, having made a distinction between `reconstructing' quantum theory and `reinventing' quantum theory, I suggest that there is an adequate (not `cheap') instrumentalist approach to the theory (and to these theorems) that invokes both.

  9. Allograft safety in anterior cruciate ligament reconstruction.

    Science.gov (United States)

    Cohen, Steven B; Sekiya, Jon K

    2007-10-01

    Allograft tissue seems to provide an excellent option for reconstruction of the ACL in the primary and revision setting. Although in general the risks of using allograft tissue in ACL reconstruction are low, the consequences of complications associated with disease or infection transmission or of recurrent instability secondary to graft failure are large. Surgeons should provide patients with the information available regarding allograft risks and should have thorough knowledge of the source and preparation of the grafts by their tissue bank before implantation for ACL reconstruction.

  10. Dynamical networks reconstructed from time series

    CERN Document Server

    Levnajić, Zoran

    2012-01-01

    Novel method of reconstructing dynamical networks from empirically measured time series is proposed. By statistically examining the correlations between motions displayed by network nodes, we derive a simple equation that directly yields the adjacency matrix, assuming the intra-network interaction functions to be known. We illustrate the method's implementation on a simple example and discuss the dependence of the reconstruction precision on the properties of time series. Our method is applicable to any network, allowing for reconstruction precision to be maximized, and errors to be estimated.

  11. Climate forcing reconstructions for use in PMIP simulations of the last millennium (v1.0

    Directory of Open Access Journals (Sweden)

    G. A. Schmidt

    2011-01-01

    Full Text Available Simulations of climate over the Last Millennium (850–1850 CE have been incorporated into the third phase of the Paleoclimate Modelling Intercomparison Project (PMIP3. The drivers of climate over this period are chiefly orbital, solar, volcanic, changes in land use/land cover and some variation in greenhouse gas levels. While some of these effects can be easily defined, the reconstructions of solar, volcanic and land use-related forcing are more uncertain. We describe here the approach taken in defining the scenarios used in PMIP3, document the forcing reconstructions and discuss likely implications.

  12. Three dimensional image reconstruction based on a wide-field optical coherence tomography system

    Science.gov (United States)

    Feng, Yinqi; Feng, Shengtong; Zhang, Min; Hao, Junjun

    2014-07-01

    Wide-field optical coherence tomography has a promising application for its high scanning rate and resolution. The principle of a wide-field optical coherence tomography system is described, and 2D images of glass slides are reconstructed using eight-stepped phase-shifting method in the system. Using VC6.0 and OpenGL programming, 3D images are reconstructed based on the Marching Cube algorithm with 2D image sequences. The experimental results show that the depth detection and three-dimensional tomography for translucent materials could be implemented efficiently in the WFOCT system.

  13. Iterative reconstruction of a region of interest for transmission tomography.

    Science.gov (United States)

    Ziegler, Andy; Nielsen, Tim; Grass, Michael

    2008-04-01

    It was shown that images reconstructed for transmission tomography with iterative maximum likelihood (ML) algorithms exhibit a higher signal-to-noise ratio than images reconstructed with filtered back-projection type algorithms. However, a drawback of ML reconstruction in particular and iterative reconstruction in general is the requirement that the reconstructed field of view (FOV) has to cover the whole volume that contributes to the absorption. In the case of a high resolution reconstruction, this demands a huge number of voxels. This article shows how an iterative ML reconstruction can be limited to a region of interest (ROI) without losing the advantages of a ML reconstruction. Compared with a full FOV ML reconstruction, the reconstruction speed is mainly increased by reducing the number of voxels which are necessary for a ROI reconstruction. In addition, the speed of convergence is increased.

  14. Novel extraction algorithm for amplitude and phase measurement of ultrashort optical pulses via spectral phase interferometry

    CERN Document Server

    Pasquazi, Alessia; Azana, Jose; Moss, David J; Morandotti, Roberto

    2014-01-01

    We present a novel extraction algorithm for spectral phase interferometry for direct field reconstruction (SPIDER) for the so-called X-SPIDER configuration. Our approach largely extends the measurable time windows of pulses without requiring any modification to the experimental X-SPIDER set-up.

  15. Precision muon reconstruction in Double Chooz

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Y. [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Anjos, J.C. dos [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, RJ 22290-180 (Brazil); Barriere, J.C. [Commissariat à l' Energie Atomique et aux Energies Alternatives, Centre de Saclay, IRFU, 91191 Gif-sur-Yvette (France); Baussan, E. [IPHC, Université de Strasbourg, CNRS/IN2P3, 67037 Strasbourg (France); Bekman, I. [III. Physikalisches Institut, RWTH Aachen University, 52056 Aachen (Germany); Bergevin, M. [University of California, Davis, CA 95616 (United States); Bezerra, T.J.C. [Research Center for Neutrino Science, Tohoku University, Sendai 980-8578 (Japan); Bezrukov, L. [Institute of Nuclear Research of the Russian Academy of Sciences, Moscow 117312 (Russian Federation); Blucher, E. [The Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637 (United States); Buck, C. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Busenitz, J. [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Cabrera, A. [AstroParticule et Cosmologie, Université Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cité, 75205 Paris Cedex 13 (France); Caden, E. [Department of Physics, Drexel University, Philadelphia, PA 19104 (United States); Camilleri, L.; Carr, R. [Columbia University, New York, NY 10027 (United States); Cerrada, M. [Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, CIEMAT, 28040 Madrid (Spain); Chang, P.-J. [Department of Physics, Kansas State University, Manhattan, KS 66506 (United States); Chauveau, E. [Research Center for Neutrino Science, Tohoku University, Sendai 980-8578 (Japan); and others

    2014-11-11

    We describe a muon track reconstruction algorithm for the reactor anti-neutrino experiment Double Chooz. The Double Chooz detector consists of two optically isolated volumes of the liquid scintillator viewed by PMTs, and an Outer Veto above these made of crossed scintillator strips. Muons are reconstructed by their Outer Veto hit positions along with timing information from the other two detector volumes. All muons are fit under the hypothesis that they are through-going and ultrarelativistic. If the energy depositions suggest that the muon may have stopped, the reconstruction fits also for this hypothesis and chooses between the two via the relative goodness-of-fit. In the ideal case of a through-going muon intersecting the center of the detector, the resolution is ∼40mm in each transverse dimension. High quality muon reconstruction is an important tool for reducing the impact of the cosmogenic isotope background in Double Chooz.

  16. IIR GRAPPA for parallel MR image reconstruction.

    Science.gov (United States)

    Chen, Zhaolin; Zhang, Jingxin; Yang, Ran; Kellman, Peter; Johnston, Leigh A; Egan, Gary F

    2010-02-01

    Accelerated parallel MRI has advantage in imaging speed, and its image quality has been improved continuously in recent years. This paper introduces a two-dimensional infinite impulse response model of inverse filter to replace the finite impulse response model currently used in generalized autocalibrating partially parallel acquisitions class image reconstruction methods. The infinite impulse response model better characterizes the correlation of k-space data points and better approximates the perfect inversion of parallel imaging process, resulting in a novel generalized image reconstruction method for accelerated parallel MRI. This k-space-based reconstruction method includes the conventional generalized autocalibrating partially parallel acquisitions class methods as special cases and has a new infinite impulse response data estimation mechanism for effective improvement of image quality. The experiments on in vivo MRI data show that the proposed method significantly reduces reconstruction errors compared with the conventional two-dimensional generalized autocalibrating partially parallel acquisitions method, particularly at the high acceleration rates.

  17. SIMD studies in the LHCb reconstruction software

    CERN Document Server

    Campora Perez, D H

    2015-01-01

    During the data taking process in the LHC at CERN, millions of collisions are recorded every second by the LHCb Detector. The LHCb Online computing farm, counting around 15000 cores, is dedicated to the reconstruction of the events in real-time, in order to filter those with interesting Physics. The ones kept are later analysed $Offline$ in a more precise fashion on the Grid. This imposes very stringent requirements on the reconstruction software, which has to be as efficient as possible. Modern CPUs support so-called vector-extensions, which extend their Instruction Sets, allowing for concurrent execution across functional units. Several libraries expose the Single Instruction Multiple Data programming paradigm to issue these instructions. The use of vectorisation in our codebase can provide performance boosts, leading ultimately to Physics reconstruction enhancements. In this paper, we present vectorisation studies of significant reconstruction algorithms. A variety of vectorisation libraries are analysed a...

  18. 40 CFR 60.673 - Reconstruction.

    Science.gov (United States)

    2010-07-01

    ... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Nonmetallic Mineral Processing Plants § 60.673 Reconstruction. (a) The cost of replacement of ore-contact surfaces on processing equipment...

  19. 40 CFR 60.383 - Reconstruction.

    Science.gov (United States)

    2010-07-01

    ... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Metallic Mineral Processing Plants § 60.383 Reconstruction. (a) The cost of replacement of ore-contact surfaces on processing equipment...

  20. Neural Network Based 3D Surface Reconstruction

    Directory of Open Access Journals (Sweden)

    Vincy Joseph

    2009-11-01

    Full Text Available This paper proposes a novel neural-network-based adaptive hybrid-reflectance three-dimensional (3-D surface reconstruction model. The neural network combines the diffuse and specular components into a hybrid model. The proposed model considers the characteristics of each point and the variant albedo to prevent the reconstructed surface from being distorted. The neural network inputs are the pixel values of the two-dimensional images to be reconstructed. The normal vectors of the surface can then be obtained from the output of the neural network after supervised learning, where the illuminant direction does not have to be known in advance. Finally, the obtained normal vectors can be applied to integration method when reconstructing 3-D objects. Facial images were used for training in the proposed approach