- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Wideband 4 ?? 4 Butler Matrix in The Printed Ridge Gap Waveguide Technology for Millimeter Wave Applications
摘要： An underground nuclear explosion (UNE) can generate a shock wave that lofts surface material, resulting in surface changes that might be detectable. The Comprehensive Nuclear Test-Ban Treaty (CTBT) allows ground and airborne spectral and thermal imaging to help locate such events. Landsat 5 data on the 1998 Indian and Pakistani tests are used here to demonstrate that there are detectable changes in surface features which might be used to localize an underground nuclear test and to develop change detection techniques speci?c to the use of satellite data to support a CTBT on-site inspection. Landsat 5 has been active for over 20 years providing repeat coverage of the Earth’s surface every 16 days. Most locations have Landsat data available for a variety of dates, allowing for statistical analysis of the data to understand temporal trends and data variability on a pixel-by-pixel basis. Given the right conditions, these usual patterns of change (such as seasonal changes or weathering) can be discerned from unusual patterns of change, such as features relating to a UNE. This paper extends known change detection techniques to a temporal series of data and shows that multispectral change detection can be used to help localize a UNE.
关键词： multispectral change detection,Comprehensive Nuclear Test-Ban Treaty (CTBT),covariance matrix Landsat 5,Mahalanobis distance
更新于2025-09-23 15:21:01
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The classification of plants by laser-induced breakdown spectroscopy based on two chemometric methods
摘要： The applications of laser-induced breakdown spectroscopy (LIBS) on classifying complex natural organics are relatively limited and their accuracies still needs to be improved. To study the methods on classification of complex organics, three kinds of fresh leaves were measured by LIBS in this work. 100 spectra from 100 samples of each kind of leaves were measured and then they were divided into training set and test set in a ratio of 7:3. Two algorithms of chemometric methods including the partial least squares discriminant analysis (PLS-DA) and principal component analysis Mahalanobis distance (PCA-MD) were used to identify these leaves. By using 23 lines from 16 elements or molecules as input data, these two methods can both classify these three kinds of leaves successfully. The classification accuracies of training set are both up to 100% by PCA-MD and PLS-DA, respectively. The classification accuracies of test set are 93.3% by PCA-MD and 97.8% by PLS-DA, respectively. It means that PLS-DA is better than PCA-MD in classifying plant leaves. Because the components in PLS-DA process are more suitable for classification than those in PCA-MD process. We think that this work can provide a reference for plant traceability using LIBS.
关键词： classification of complex organics,partial least squares discriminant analysis,principal component analysis Mahalanobis distance,laser-induced breakdown spectroscopy
更新于2025-09-23 15:21:01
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Compact Single-Shot D-Scan Setup for the Characterization of Few-Cycle Laser Pulses
摘要： The power generator is typically maintained with a time- or usage-based strategy, which could result in a substantial waste of remaining useful life, high maintenance cost, and low plant availability. Recently, the field of prognostics and health management offers diagnostic and prognostic techniques to precisely assess the health condition and robustly predict the remaining useful life (RUL) of an engineered system, with an aim to address the aforementioned deficiencies. This paper explores a smart health reasoning system to assess the health condition of power generator stator bars against moisture absorption based on the statistical analysis of the capacitance measurements on bar insulators. In particular, a relative health measure, namely the directional Mahalanobis distance, is proposed to quantify the health condition of a stator bar. The smart health reasoning system is validated using five years’ field data from seven generators, each of which contains 42 turns.
关键词： health diagnostics,statistical correlation,moisture absorption,Directional Mahalanobis distance (DMD),power generator stator bar
更新于2025-09-19 17:13:59
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In situ gas monitoring by fiber-coupled Raman spectrometry for H2-risk management in nuclear containment during a severe nuclear accident
摘要： An underground nuclear explosion (UNE) can generate a shock wave that lofts surface material, resulting in surface changes that might be detectable. The Comprehensive Nuclear Test-Ban Treaty (CTBT) allows ground and airborne spectral and thermal imaging to help locate such events. Landsat 5 data on the 1998 Indian and Pakistani tests are used here to demonstrate that there are detectable changes in surface features which might be used to localize an underground nuclear test and to develop change detection techniques speci?c to the use of satellite data to support a CTBT on-site inspection. Landsat 5 has been active for over 20 years providing repeat coverage of the Earth’s surface every 16 days. Most locations have Landsat data available for a variety of dates, allowing for statistical analysis of the data to understand temporal trends and data variability on a pixel-by-pixel basis. Given the right conditions, these usual patterns of change (such as seasonal changes or weathering) can be discerned from unusual patterns of change, such as features relating to a UNE. This paper extends known change detection techniques to a temporal series of data and shows that multispectral change detection can be used to help localize a UNE.
关键词： multispectral change detection,Comprehensive Nuclear Test-Ban Treaty (CTBT),covariance matrix Landsat 5,Mahalanobis distance
更新于2025-09-16 10:30:52
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Difference-based target detection using Mahalanobis distance and spectral angle
摘要： Two difference-based target detection methods are proposed in this work. In contrast to many target detectors which only calculate the distance between the testing pixel to the target spectrum, the proposed methods calculate the distance of the testing pixel to both of target and of background spectra. In other words, they utilize the difference between target and background computed distances. The first proposed method uses the Mahalanobis distance and benefits the valuable information contained in the statistics of targets and background. The second proposed method uses the kernel-based spectral angle mapper to benefit the advantages of spectral angle and kernel trick to separate targets from background, especially in non-linear cases. The experiments done on three real hyperspectral images indicate the high detection probability of the proposed methods compared to several target detectors.
关键词： hyperspectral imaging,Mahalanobis distance,target detection,spectral angle
更新于2025-09-09 09:28:46