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A new archive of large volcanic events over the past millennium derived from reconstructed summer temperatures

ENVIRONMENTAL RESEARCH LETTERS 2017年第9期12卷 094005-094005页

作者： Schneider, L. Smerdon, J. E. Pretis, F. Hartl-Meier, C. Esper, J. Justus Liebig Univ Dept Geog Giessen Germany Columbia Univ Lamont Doherty Earth Observ Palisades NY USA Univ Oxford Oxford Martin Sch Programme Econ Modelling INET Oxford England Univ Oxford Dept Econ Oxford England Johannes Gutenberg Univ Mainz Dept Geog Mainz Germany

Information about past volcanic impact on climate is mostly derived from historic documentary data and sulfate depositions in polar ice sheets. Although these archives have provided important insights into the Earth's volcanic eruption history, the climate forcing and exact dating of many events is still vague. Here we apply a new method of break detection to the first millennium-length maximum latewood density reconstruction of Northern Hemisphere summer temperatures to develop an alternative record of large volcanic eruptions. The analysis returns fourteen outstanding cooling events, all of which agree well with recently developed volcanic forcing records from high-resolution bipolar ice cores. In some cases, however, the climatic impact detected with our new method peaks in neighboring years, likely due to either dating errors in the polar ice cores or uncertainty in the interpretation of atmospheric aerosol transport to polar ice core locations. The most apparent mismatches between forcing and cooling estimates occur in the 1450s and 1690s. Application of the algorithm to two additional and recently developed reconstructions that blend maximum latewood density and ring width data reproduces twelve of the detected events among which eight are retrieved in all three of the dendroclimatic reconstructions. Collectively, the new estimates of volcanic activity with precise age control provide independent evidence for forcing records during the last millennium. Evaluating the cooling magnitude in response to detected events yields an upper benchmark for the volcanic impact on climate. The average response to the ten major events in the density derived reconstruction is -0.60 degrees C +/- 0.13 degrees C. Other last millennium temperature records from proxies and model simulations reveal higher cooling estimates, which is, to some degree, related to the very different high frequency variance in these timeseries.

关键词： volcanic cooling forcing reconstruction tree-ring density Northern Hemisphere detection algorithm last-millennium simulations indicator saturation

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Detecting a theta or a prism

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SIAM JOURNAL ON DISCRETE MATHEMATICS 2008年第3期22卷 1164-1186页

作者： Chudnovsky, Maria Kapadia, Rohan Columbia Univ IEOR New York NY 10027 USA McGill Univ Dept Math Montreal PQ H3A 2K6 Canada

A theta in a graph is an induced subgraph consisting of two nonadjacent vertices joined by three disjoint paths. A prism in a graph is an induced subgraph consisting of two disjoint triangles joined by three disjoint paths. This paper gives a polynomial-time algorithm to test whether a graph has an induced subgraph that is either a prism or a theta.

关键词： induced subgraph detection algorithm theta prism

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Fine-tuning the search for microsatellites

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JOURNAL OF DISCRETE algorithmS 2013年 20卷 21-37页

作者： de Ridder, C. Kourie, D. G. Watson, B. W. Fourie, T. R. Reyneke, P. V. UNISA Sch Comp ZA-0002 Pretoria South Africa Univ Pretoria Fastar Res Grp ZA-0002 Pretoria South Africa Univ Stellenbosch Fastar Res Grp ZA-7602 Stellenbosch South Africa Denel Dynam Dept Radar & Imaging Syst ZA-0157 Irene South Africa

The design and implementation is discussed of Fire mu Sat(2), an algorithm to detect microsatellites (Short approximate tandem repeats) in DNA. The algorithm relies on deterministic finite automata. The parameters are designed to support requirements expressed by molecular biologists in data exploration. By setting the parameters of Fire mu Sat(2) as liberally as possible, Fire mu Sat(2) is able to detect more microsatellites than all other software algorithms that we have encountered. Furthermore Fire mu Sat(2) was found to be faster than all the other algorithms that were investigated for approximate tandem repeat detection. In addition to being fast and accurate, the Fire mu Sat(2) algorithm that is described is robust and easily useable. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Finite automata Microsatellite detection Repeat detection Pattern matching detection algorithm

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GENERATION OF SET MEMBERSHIP TESTS FOR FAULT DIAGNOSIS AND EVALUATION OF THEIR WORST CASE SENSITIVITY

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IFAC Proceedings Volumes 2006年第13期39卷 569-574页

作者： Abdelhalim Lalami Christophe Combastel ECS-ENSEA 6 av. du Ponceau 95014 Cergy-Pontoise Cedex France Tel: +33 1 30 73 62 64 Fax: +33 1 30 73 66 27

Fault diagnosis based on the characterisation of operation ranges is proposed in this work. Set membership approaches are used to compute zonotopes used to implement detection and isolation tests. The proposed approach relies on the integration of residual generation and evaluation by testing the membership of the observations to some domains. An a priori evaluation of the worst case sensitivity of the tests is also proposed. The application to a current controlled DC motor illustrates the approach developed in the paper. Copyright © 2006 IFAC

关键词： Fault diagnosis detection algorithm intervals sets sensitivity analysis uncertain linear systems decoupling problems zonotopes

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Multisensor Characterization of the Incandescent Jet Region of Lava Fountain-Fed Tephra Plumes

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REMOTE SENSING 2020年第21期12卷 3629页

作者： Mereu, Luigi Scollo, Simona Bonadonna, Costanza Freret-Lorgeril, Valentin Marzano, Frank Silvio Sapienza Univ Rome Dept Informat Engn I-00184 Rome Italy Ctr Excellence CETEMPS I-67100 Laquila Italy Osservatorio Etneo Ist Nazl Geofis & Vulcanol I-95125 Catania Italy Univ Geneva Dept Earth Sci CH-1205 Geneva Switzerland

Explosive basaltic eruptions eject a great amount of pyroclastic material into the atmosphere, forming columns rising to several kilometers above the eruptive vent and causing significant disruption to both proximal and distal communities. Here, we analyze data, collected by an X-band polarimetric weather radar and an L-band Doppler fixed-pointing radar, as well as by a thermal infrared (TIR) camera, in relation to lava fountain-fed tephra plumes at the Etna volcano in Italy. We clearly identify a jet, mainly composed of lapilli and bombs mixed with hot gas in the first portion of these volcanic plumes and here called the incandescent jet region (IJR). At Etna and due to the TIR camera configuration, the IJR typically corresponds to the region that saturates thermal images. We find that the IJR is correlated to a unique signature in polarimetric radar data as it represents a zone with a relatively high reflectivity and a low copolar correlation coefficient. Analyzing five recent Etna eruptions occurring in 2013 and 2015, we propose a jet region radar retrieval algorithm (JR3A), based on a decision-tree combining polarimetric X-band observables with L-band radar constraints, aiming at the IJR height detection during the explosive eruptions. The height of the IJR does not exactly correspond to the height of the lava fountain due to a different altitude, potentially reached by lapilli and blocks detected by the X-band weather radar. Nonetheless, it can be used as a proxy of the lava fountain height in order to obtain a first approximation of the exit velocity of the mixture and, therefore, of the mass eruption rate. The comparisons between the JR3A estimates of IJR heights with the corresponding values recovered from TIR imagery, show a fairly good agreement with differences of less than 20% in clear air conditions, whereas the difference between JR3A estimates of IJR height values and those derived from L-band radar data only are greater than 40%. The advantage of usi

关键词： eruption plume polarimetric radar Doppler radar thermal-infrared camera jet region exit velocity detection algorithm

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MULTI-LOOP CONTROLLERS USING WAVELET PACKET DECOMPOSITION FOR FILM PROCESSES

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IFAC Proceedings Volumes 2002年第1期35卷 7-12页

作者： Yoshihiro Hashimoto Koji Urase Toshiaki Itoh Takashi Hamaguchi Yoshitaka Togari Haruhiko Maki Norikazu Yasutomo Dept. of Systems Management and Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Dept. of Systems Engineering Nagoya Institute of Technology Nagoya 466-8555 Japan Shiga Plant Kaneka Corporation Otsu 520-0104 Japan

In film processes, many actuators and scanning sensors are utilized to control film properties. Multi-loop controllers are applied to the pairs of actuators and scanned data, because they can be tuned without the precise process models. The selection of the measurement location corresponding to an actuator is not easy because the film is stretched and its edges are cut off. It is illustrated that inadequate pairing causes deterioration of the multi-loop controller performance. A method based on wavelet analysis is proposed to detect inadequate pairing and to prevent the deterioration of the controller performance.

关键词： Multiloop control Distribution control Process control detection algorithm Saturation control

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In-vivo quality assurance of dynamic tumor tracking (DTT) for liver SABR using EPID images

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JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS 2023年第7期24卷 e13969页

作者： Rostamzadeh, Maryam Luchka, Kurt Ma, Roy Liu, Mitchell Dunne, Emma Camborde, Marie-Laure Karan, Tania Mestrovic, Ante Bergman, Alanah Univ British Columbia Dept Phys & Astron Vancouver BC Canada BC Cancer Vancouver Med Phys Dept Vancouver BC Canada BC Cancer Vancouver Radiat Oncol Dept Vancouver BC Canada Univ British Columbia Dept Phys & Astron 325-6224 Agr Rd Vancouver BC V6T 1Z1 Canada

PurposeTo assess dynamic tumor tracking (DTT) target localization uncertainty for in-vivo marker-based stereotactic ablative radiotherapy (SABR) treatments of the liver using electronic-portal-imaging-device (EPID) images. The Planning Target Volume (PTV) margin contribution for DTT is estimated. MethodsPhantom and patient EPID images were acquired during non-coplanar 3DCRT-DTT delivered on a Vero4DRT linac. A chain-code algorithm was applied to detect Multileaf Collimator (MLC)-defined radiation field edges. Gold-seed markers were detected using a connected neighbor algorithm. For each EPID image, the absolute differences between the measured center-of-mass (COM) of the markers relative to the aperture-center (Tracking Error, (E-T)) was reported in pan, tilt, and 2D-vector directions at the isocenter-plane. Phantom studyAn acrylic cube phantom implanted with gold-seed markers was irradiated with non-coplanar 3DCRT-DTT beams and EPID images collected. Patient Study: Eight liver SABR patients were treated with non-coplanar 3DCRT-DTT beams. All patients had three to four implanted gold-markers. In-vivo EPID images were analyzed. ResultsPhantom Study: On the 125 EPID images collected, 100% of the markers were identified. The average +/- SD of E-T were 0.24 +/- 0.21, 0.47 +/- 0.38, and 0.58 +/- 0.37 mm in pan, tilt and 2D directions, respectively. Patient Study: Of the 1430 EPID patient images acquired, 78% had detectable markers. Over all patients, the average +/- SD of E-T was 0.33 +/- 0.41 mm in pan, 0.63 +/- 0.75 mm in tilt and 0.77 +/- 0.80 mm in 2D directions The random 2D-error, sigma, for all patients was 0.79 mm and the systematic 2D-error, sigma, was 0.20 mm. Using the Van Herk margin formula 1.1 mm planning target margin can represent the marker based DTT uncertainty. ConclusionsMarker-based DTT uncertainty can be evaluated in-vivo on a field-by-field basis using EPID images. This information can contribute to PTV margin calculations for DTT.

关键词： detection algorithm dynamic tumor tracking EPID marker detection position verification

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Flight Control System improvement based on a software sensor derived from Partial Least Squares algorithm

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IFAC Proceedings Volumes 2012年第20期45卷 1041-1046页

作者： Florian Cazes Marie Chabert Corinne Mailhes Patrice Michel Philippe Goupil Rémy Dayre Hervé Le-Berre EYCCC Flight Control System AIRBUS Operations S.A.S. Toulouse France University of Toulouse/IRIT/ENSEEIHT TéSA Lab

Global aircraft optimization is a main concern for future and upcoming programs. In particular, great research efforts are dedicated to Electrical Flight Control Systems (EFCS). Obviously, their reliability increases with the redundancy of the flight parameter sensors. However, physical redundancy, obtained by increasing the number of sensors, penalizes the aircraft weight and cost. This paper proposes a sensor failure detection method based on analytic redundancy. The flight parameter of interest is modelled as a linear function of independent sensor measurements on a sliding observation window. The Partial Least Squares (PLS) algorithm is used to estimate regression coefficients on this window. The PLS computes the solution via an iterative processing, and thus can be implemented in the flight control computer for a real time use. Two different failure detection strategies based on the behaviour of the regression coefficients are proposed. Simulation results show that the proposed method leads to robust detections.

关键词： Aircraft control command and control systems detection algorithm failure detection least squares algorithm sensor failure partial least squares

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Color Targets: Fiducials to Help Visually Impaired People Find Their Way by Camera Phone

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EURASIP JOURNAL ON IMAGE AND VIDEO PROCESSING 2007年第unknown期2007卷 096357-096357页

作者： Coughlan, James Manduchi, Roberto Smith Kettlewell Eye Res Inst Rehabil Engn Res Ctr San Francisco CA 94115 USA Univ Calif Santa Cruz Santa Cruz CA 95064 USA

A major challenge faced by the blind and visually impaired population is that of wayfinding-the ability of a person to find his or her way to a given destination. We propose a new wayfinding aid based on a camera cell phone, which is held by the user to find and read aloud specially designed machine-readable signs, which we call color targets, in indoor environments (labeling locations such as offices and restrooms). Our main technical innovation is that we have designed the color targets to be detected and located in fractions of a second on the cell phone CPU, even at a distance of several meters. Once the sign has been quickly detected, nearby information in the form of a barcode can be read, an operation that typically requires more computational time. An important contribution of this paper is a principled method for optimizing the design of the color targets and the color target detection algorithm based on training data, instead of relying on heuristic choices as in our previous work. We have implemented the system on Nokia 7610 cell phone, and preliminary experiments with blind subjects demonstrate the feasibility of using the system as a real-time wayfinding aid. Copyright (c) 2007 J. Coughlan and R. Manduchi.

关键词： Training Data Computer Vision Computational Time detection algorithm Cell Phone

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Evaluation of syndromic algorithms for detecting patients with potentially transmissible infectious diseases based on computerised emergency-department data

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BMC MEDICAL INFORMATICS AND DECISION MAKING 2013年第1期13卷 1-10页

作者： Gerbier-Colomban, Solweig Gicquel, Quentin Millet, Anne-Laure Riou, Christophe Grando, Jacqueline Darmoni, Stefan Potinet-Pagliaroli, Veronique Metzger, Marie-Helene Hop Croix Rousse Hosp Civils Lyon Unite Hyg & Epidemiol F-69317 Lyon France Univ Lyon F-69000 Lyon France Univ Lyon 1 CNRS Lab Biometrie & Biol Evolut UMR5558 F-69622 Villeurbanne France Hosp Civils Lyon Direct Syst Informat & Informat F-69500 Bron France Hosp Civils Lyon Pole Informat Med Evaluat Rech F-69424 Lyon France Hop Croix Rousse Hosp Civils Lyon Serv Urgences F-69317 Lyon France Hosp Civils Lyon Serv Hyg & Epidemiol F-69565 St Genis Laval France LITIS EA 4108 Univ Rouen CISMeF F-76031 Rouen France Hop Croix Rousse Serv Hyg Epidemiol & Prevent F-69317 Lyon 04 France

Background: The objective of this study was to ascertain the performance of syndromic algorithms for the early detection of patients in healthcare facilities who have potentially transmissible infectious diseases, using computerised emergency department (ED) data. Methods: A retrospective cohort in an 810-bed University of Lyon hospital in France was analysed. Adults who were admitted to the ED and hospitalised between June 1, 2007, and March 31, 2010 were included (N=10895). Different algorithms were built to detect patients with infectious respiratory, cutaneous or gastrointestinal syndromes. The performance parameters of these algorithms were assessed with regard to the capacity of our infection-control team to investigate the detected cases. Results: For respiratory syndromes, the sensitivity of the detection algorithms was 82.70%, and the specificity was 82.37%. For cutaneous syndromes, the sensitivity of the detection algorithms was 78.08%, and the specificity was 95.93%. For gastrointestinal syndromes, the sensitivity of the detection algorithms was 79.41%, and the specificity was 81.97%. Conclusions: This assessment permitted us to detect patients with potentially transmissible infectious diseases, while striking a reasonable balance between true positives and false positives, for both respiratory and cutaneous syndromes. The algorithms for gastrointestinal syndromes were not specific enough for routine use, because they generated a large number of false positives relative to the number of infected patients. detection of patients with potentially transmissible infectious diseases will enable us to take precautions to prevent transmission as soon as these patients come in contact with healthcare facilities.

关键词： Emergency service Hospital Syndromic surveillance detection algorithm Infection control Sensitivity and specificity Population surveillance

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