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  • 1
    Online-Ressource
    Online-Ressource
    Singapore :Springer,
    Schlagwort(e): Data mining. ; Electronic books.
    Materialart: Online-Ressource
    Seiten: 1 online resource (287 pages)
    Ausgabe: 1st ed.
    ISBN: 9789811595196
    DDC: 006.312
    Sprache: Englisch
    Anmerkung: Intro -- Foreword -- Preface -- Acknowledgements -- Contents -- About the Authors -- Abbreviations -- Part IIntroduction -- 1 Overview and Contributions -- 1.1 Introduction -- 1.2 Research Issues on Unsupervised Outlier Detection -- 1.3 Overview of the Book -- 1.4 Contributions -- 1.5 Conclusions -- 2 Developments in Unsupervised Outlier Detection Research -- 2.1 Introduction -- 2.1.1 A Brief Overview of the Early Developments in Outlier Analysis -- 2.2 Some Standard Unsupervised Outlier Detection Approaches -- 2.2.1 Probabilistic Model-Based Outlier Detection Approach -- 2.2.2 Clustering-Based Outlier Detection Approaches -- 2.2.3 Distance-Based Outlier Detection Approaches -- 2.2.4 Density-Based Outlier Detection Approaches -- 2.2.5 Outlier Detection for Time Series -- 2.3 Performance Evaluation Metrics of Outlier Detection Approaches -- 2.3.1 Precision, Recall and Rank Power -- 2.4 Conclusions -- References -- Part IINew Developments in Unsupervised Outlier Detection Research -- 3 A Fast Distance-Based Outlier Detection Technique Using a Divisive Hierarchical Clustering Algorithm -- 3.1 Introduction -- 3.2 Related Work -- 3.2.1 Distance-Based Outlier Detection Research -- 3.2.2 A Divisive Hierarchical Clustering Algorithm for Approximate kNN Search -- 3.2.3 An Efficiency Analysis of DHCA for Distance-Based Outlier Detection -- 3.3 The Proposed Fast Distance-Based Outlier Detection Algorithm -- 3.3.1 A Simple Idea -- 3.3.2 The Proposed CPU-Efficient DB-Outlier Detection Method -- 3.3.3 Time Complexity Analysis -- 3.3.4 Data Structure for Implementing DHCA -- 3.4 Scale to Very Large Databases with I/O Efficiency -- 3.5 Performance Evaluation -- 3.5.1 Data Characteristics -- 3.5.2 The Impact of Input K on Running Time -- 3.5.3 Comparison with Other Methods -- 3.5.4 Effectiveness of DHCA for kNN Search. , 3.5.5 The Impact of Curse of Dimensionality -- 3.5.6 Scale to Very Large Databases with I/O Efficiency -- 3.5.7 Discussion -- 3.6 Conclusions -- References -- 4 A k-Nearest Neighbor Centroid-Based Outlier Detection Method -- 4.1 Introduction -- 4.2 K-means Clustering and Its Application to Outlier Detection -- 4.2.1 K-means Clustering -- 4.2.2 K-means Clustering-Based Outlier Detection -- 4.3 A kNN-Centroid-Based Outlier Detection Algorithm -- 4.3.1 General Idea -- 4.3.2 Definition for an Outlier Indicator -- 4.3.3 Formal Definition of kNN-Based Centroid -- 4.3.4 Two New Formulations of Outlier Factors -- 4.3.5 Determination of k -- 4.3.6 The Complexity Analysis -- 4.3.7 The Proposed Outlier Detection Algorithm -- 4.4 A Performance Study -- 4.4.1 Performance on Synthetic Datasets -- 4.4.2 Performance on Real Datasets -- 4.4.3 Performance on High-Dimensional Real Datasets -- 4.4.4 Discussion -- 4.5 Conclusions -- References -- 5 A Minimum Spanning Tree Clustering-Inspired Outlier Detection Technique -- 5.1 Introduction -- 5.2 Background -- 5.2.1 Minimum Spanning Tree-Based Clustering -- 5.2.2 Minimum Spanning Tree Clustering-Based Outlier Detection -- 5.3 An Improved MST-Clustering-Inspired Outlier Detection Algorithm -- 5.3.1 A Simple Idea -- 5.3.2 Two New Outlier Factors -- 5.3.3 The Proposed MST-Clustering-Inspired Outlier Detection Algorithm -- 5.3.4 Time Complexity Analysis -- 5.4 A Performance Study -- 5.4.1 Performance on Synthetic Datasets -- 5.4.2 Performance on Multi-dimensional Real Datasets -- 5.4.3 Performance of the Proposed Algorithm with Varying SOM-TH -- 5.5 Concluding Remarks -- References -- 6 A k-Nearest Neighbour Spectral Clustering-Based Outlier Detection Technique -- 6.1 Introduction -- 6.2 Spectral Clustering and Its Application to Outlier Detection -- 6.2.1 Preliminaries -- 6.2.2 Spectral Clustering-Based Outlier Detection. , 6.3 The Proposed Spectral Clustering-Based Outlier Mining Algorithm -- 6.3.1 A Simple Idea -- 6.3.2 The Proposed Outlier Detection Algorithm -- 6.3.3 Complexity Analysis -- 6.4 Experimental Results -- 6.4.1 Performance of Our Algorithm on Synthetic Data -- 6.4.2 Performance of Our Algorithm on Real Data -- 6.5 Discussion -- 6.6 Conclusions -- References -- 7 Enhancing Outlier Detection by Filtering Out Core Points and Border Points -- 7.1 Introduction -- 7.2 Related Work -- 7.2.1 Density-Based Clustering with DBSCAN -- 7.2.2 Density-Based Clustering for Outlier Detection -- 7.3 The Proposed Enhancer for Outlier Mining -- 7.3.1 A Simple Idea -- 7.3.2 Some Definitions -- 7.3.3 Our Proposed Outlier Detection Algorithm -- 7.3.4 The Complexity Analysis -- 7.4 Experiments and Results -- 7.4.1 Performance of Our Algorithm on Synthetic Data -- 7.4.2 Performance of Our Algorithm on Real Data -- 7.5 Conclusions -- References -- Part IIIApplications -- 8 An Effective Boundary Point Detection Algorithm Via k-Nearest Neighbors-Based Centroid -- 8.1 Introduction -- 8.2 Related Work -- 8.2.1 Outlier and Boundary Point Detection -- 8.2.2 EMST Algorithms -- 8.3 Boundary Point Detection Based on kNN Centroid -- 8.3.1 Definitions -- 8.3.2 The Proposed Boundary Point and Outlier Detection Algorithm -- 8.3.3 The Complexity Analysis -- 8.4 The Proposed Fast Approximate EMST Algorithm -- 8.4.1 Our Clustering-Inspired EMST Algorithm -- 8.4.2 Time Complexity Analysis -- 8.5 Experiments and Results -- 8.5.1 Performance Evaluation of the Proposed Boundary Point Detection Algorithm -- 8.5.2 Performance Evaluation of the Fast Approximate EMST Algorithm -- 8.6 Conclusions -- References -- 9 A Nearest Neighbor Classifier-Based Automated On-Line Novel Visual Percept Detection Method -- 9.1 Introduction -- 9.2 A Percept Learning System -- 9.2.1 Feature Generation. , 9.2.2 Similarity Measure -- 9.2.3 Percept Formation -- 9.2.4 A Fast Approximate Nearest Neighbor Classifier -- 9.3 An On-Line Novelty Detection Method -- 9.3.1 A Threshold Selection Method -- 9.3.2 Eight-Connected Structure Element Filter -- 9.3.3 Tree Update Method -- 9.4 Experiments and Results -- 9.4.1 Experiment I: An Indoor Environment -- 9.4.2 Experiment II: An Outdoor Environment -- 9.5 Conclusions -- References -- 10 Unsupervised Fraud Detection in Environmental Time Series Data -- 10.1 Introduction -- 10.2 Related Work -- 10.2.1 Point Outliers -- 10.2.2 Shape Outliers -- 10.3 Method -- 10.3.1 A Simple Idea -- 10.3.2 Selecting an Appropriate Threshold for Fraud Detection -- 10.3.3 The Complexity Analysis -- 10.4 Experiments and Results -- 10.4.1 Fraud Detection on Wastewater Discharge Concentration Data -- 10.4.2 Fraud Detection on Gas Emission Concentration Data -- 10.5 Conclusions -- References.
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  • 2
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 167-168 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We propose a general self-pumped four-wave mixing device in which the pump waves are derived from a single incident optical beam. In a single-mode fiber, only the fundamental mode of the fiber can propagate. The output of a single-mode fiber can provide pump waves of four-wave mixing. We have demonstrated that the phase distortion is eliminated by using this device.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd.
    International journal of dermatology 43 (2004), S. 0 
    ISSN: 1365-4632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
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  • 4
    Publikationsdatum: 2021-06-25
    Beschreibung: The interannual-decadal variability of the wintertime mixed layer depths (MLDs) over the North Pacific is investigated from an empirical orthogonal function (EOF) analysis of an ensemble of global ocean reanalyses. The first leading EOF mode represents the interannual MLD anomalies centered in the eastern part of the central mode water formation region in phase opposition with those in the eastern subtropics and the central Alaskan Gyre. This first EOF mode is highly correlated with the Pacific decadal oscillation index on both the interannual and decadal time scales. The second leading EOF mode represents the MLD variability in the subtropical mode water (STMW) formation region and has a good correlation with the wintertime West Pacific (WP) index with time lag of 3 years, suggesting the importance of the oceanic dynamical response to the change in the surface wind field associated with the meridional shifts of the Aleutian Low. The above MLD variabilities are in basic agreement with previous observational and modeling findings. Moreover the reanalysis ensemble provides uncertainty estimates. The interannual MLD anomalies in the first and second EOF modes are consistently represented by the individual reanalyses and the amplitudes of the variabilities generally exceed the ensemble spread of the reanalyses. Besides, the resulting MLD variability indices, spanning the 1948–2012 period, should be helpful for characterizing the North Pacific climate variability. In particular, a 6-year oscillation including the WP teleconnection pattern in the atmosphere and the oceanic MLD variability in the STMW formation region is first detected.
    Beschreibung: Published
    Beschreibung: 891–907
    Beschreibung: 4A. Oceanografia e clima
    Beschreibung: JCR Journal
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 5
    Publikationsdatum: 2021-06-25
    Beschreibung: Intercomparison and evaluation of the global ocean surface mixed layer depth (MLD) fields estimated from a suite of major ocean syntheses are conducted. Compared with the reference MLDs calculated from individual profiles, MLDs calculated from monthly mean and gridded profiles show negative biases of 10–20 m in early spring related to the re-stratification process of relatively deep mixed layers. Vertical resolution of profiles also influences the MLD estimation. MLDs are underestimated by approximately 5–7 (14–16) m with the vertical resolution of 25 (50) m when the criterion of potential density exceeding the 10-m value by 0.03 kg m−3 is used for the MLD estimation. Using the larger criterion (0.125 kg m−3) generally reduces the underestimations. In addition, positive biases greater than 100 m are found in wintertime subpolar regions when MLD criteria based on temperature are used. Biases of the reanalyses are due to both model errors and errors related to differences between the assimilation methods. The result shows that these errors are partially cancelled out through the ensemble averaging. Moreover, the bias in the ensemble mean field of the reanalyses is smaller than in the observation-only analyses. This is largely attributed to comparably higher resolutions of the reanalyses. The robust reproduction of both the seasonal cycle and interannual variability by the ensemble mean of the reanalyses indicates a great potential of the ensemble mean MLD field for investigating and monitoring upper ocean processes.
    Beschreibung: Published
    Beschreibung: 753–773
    Beschreibung: 4A. Oceanografia e clima
    Beschreibung: JCR Journal
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 6
    Publikationsdatum: 2022-10-26
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chandanpurkar, H. A., Lee, T., Wang, X., Zhang, H., Fournier, S., Fenty, I., Fukumori, I., Menemenlis, D., Piecuch, C. G., Reager, J. T., Wang, O., & Worden, J. Influence of nonseasonal river discharge on sea surface salinity and height. Journal of Advances in Modeling Earth Systems, 14(2), (2022): e2021MS002715, https://doi.org/10.1029/2021MS002715.
    Beschreibung: River discharge influences ocean dynamics and biogeochemistry. Due to the lack of a systematic, up-to-date global measurement network for river discharge, global ocean models typically use seasonal discharge climatology as forcing. This compromises the simulated nonseasonal variation (the deviation from seasonal climatology) of the ocean near river plumes and undermines their usefulness for interdisciplinary research. Recently, a reanalysis-based daily varying global discharge data set was developed, providing the first opportunity to quantify nonseasonal discharge effects on global ocean models. Here we use this data set to force a global ocean model for the 1992–2017 period. We contrast this experiment with another experiment (with identical atmospheric forcings) forced by seasonal climatology from the same discharge data set to isolate nonseasonal discharge effects, focusing on sea surface salinity (SSS) and sea surface height (SSH). Near major river mouths, nonseasonal discharge causes standard deviations in SSS (SSH) of 1.3–3 practical salinity unit (1–2.7 cm). The inclusion of nonseasonal discharge results in notable improvement of model SSS against satellite SSS near most of the tropical-to-midlatitude river mouths and minor improvement of model SSH against satellite or in-situ SSH near some of the river mouths. SSH changes associated with nonseasonal discharge can be explained by salinity effects on halosteric height and estimated accurately through the associated SSS changes. A recent theory predicting river discharge impact on SSH is found to perform reasonably well overall but underestimates the impact on SSH around the global ocean and has limited skill when applied to rivers near the equator and in the Arctic Ocean.
    Beschreibung: This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004) with support from the Physical Oceanography (PO) and Modeling, Analysis, and Prediction (MAP) Programs. High-end computing resources for the numerical simulation were provided by the NASA Advanced Supercomputing Division at the Ames Research Center.
    Schlagwort(e): River discharge ; Sea surface salinity ; Sea surface height
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
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  • 7
    Publikationsdatum: 2014-03-14
    Beschreibung: Journal of the American Chemical Society DOI: 10.1021/ja501288x
    Print ISSN: 0002-7863
    Digitale ISSN: 1520-5126
    Thema: Chemie und Pharmazie
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  • 8
    Publikationsdatum: 2017-10-14
    Beschreibung: Energies, Vol. 10, Pages 1602: Rate Decline Analysis of Vertically Fractured Wells in Shale Gas Reservoirs Energies doi: 10.3390/en10101602 Authors: Xiaoyang Zhang Xiaodong Wang Xiaochun Hou Wenli Xu Based on the porous flow theory, an extension of the pseudo-functions approach for the solution of non-linear partial differential equations considering adsorption-desorption effects was used to investigate the transient flow behavior of fractured wells in shale gas reservoirs. The pseudo-time factor was employed to effectively linearize the partial differential equations of the unsteady flow response. The production performance of vertically fractured wells in shale gas reservoirs under either constant flow rate or constant bottom-hole pressure conditions was analyzed using the composite flow model. The calculation results indicate that the non-linearities that develop in the gas diffusivity equation have significant effects on the unsteady response, leading to a larger pressure depletion and rate decline in the late-time period. In addition, gas desorption from the shale acts as a recharge source, which relieves the gas production rate of decline. Greater values for the Langmuir volumes or Langmuir pressures provide additional pressure support, leading to a lower rate decline while the flowing well bottom-hole pressure is maintained. The reservoir size mainly affects the duration of the pressure depletion and rate decline. In the case of ignoring the non-linearity and adsorption-desorption effect in the differential equation, a greater rate decline under constant bottom-hole pressure production can be obtained during the boundary-dominated depletion. This work provides a better understanding of gas desorption in shale gas reservoirs and new insight into investigating the production performances of fractured gas well.
    Digitale ISSN: 1996-1073
    Thema: Energietechnik
    Publiziert von MDPI Publishing
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  • 9
    Publikationsdatum: 2012-05-03
    Beschreibung: Journal of the American Chemical Society DOI: 10.1021/ja302765m
    Print ISSN: 0002-7863
    Digitale ISSN: 1520-5126
    Thema: Chemie und Pharmazie
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  • 10
    Publikationsdatum: 2014-06-05
    Beschreibung: Analytical Chemistry DOI: 10.1021/ac500175y
    Print ISSN: 0003-2700
    Digitale ISSN: 1520-6882
    Thema: Chemie und Pharmazie
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