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Qiongxiang Huang - One of the best experts on this subject based on the ideXlab platform.
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On the Laplacian Spectral Characterization of Π-shape trees
Indian Journal of Pure and Applied Mathematics, 2018Co-Authors: Fei Wen, Qiongxiang Huang, Xueyi Huang, Fenjin LiuAbstract:A Π-shape tree is a tree with exactly two vertices having the maximum degree three. In this paper, we classify the Π-shape trees into two types, and complete the Spectral Characterization for one type. Exactly, we prove that all graphs of this type are determined by their Laplacian spectra with some exceptions. Moreover, we give some L-coSpectral mates of some graphs for another type.
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Laplacian Spectral Characterization of 3-rose graphs
Linear Algebra and its Applications, 2013Co-Authors: Fenjin Liu, Qiongxiang HuangAbstract:Abstract A 3 -rose graph is a graph consisting of three cycles intersecting in a common vertex, J. Wang et al. showed all 3-rose graphs with at least one triangle are determined by their Laplacian spectra. In this paper, we complete the above Laplacian Spectral Characterization and prove that all 3-rose graphs are determined by their Laplacian spectra.
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On the Spectral Characterization of Π-shape trees
Linear and Multilinear Algebra, 2013Co-Authors: Fenjin Liu, Qiongxiang HuangAbstract:A Π-shape tree is a tree with exactly two of its vertices having the maximum degree 3. In this article, we classify the Π-shape trees into six types according to the number of their closed walks of length 6. Then we complete the Spectral Characterization for one type. We show that all graphs of one such type are determined by the spectrum. Another type i.e., W n is known to have the unique coSpectral mate C 4 ∪ P n . Moreover, we find coSpectral graphs of some graphs for the remaining four types.
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Spectral Characterization of multicone graphs
Czechoslovak Mathematical Journal, 2012Co-Authors: Jianfeng Wang, Haixing Zhao, Qiongxiang HuangAbstract:A multicone graph is defined to be the join of a clique and a regular graph. Based on Zhou and Cho’s result [B. Zhou, H.H. Cho, Remarks on Spectral radius and Laplacian eigenvalues of a graph, Czech. Math. J. 55 (130) (2005), 781–790], the Spectral Characterization of multicone graphs is investigated. Particularly, we determine a necessary and sufficient condition for two multicone graphs to be coSpectral graphs and investigate the structures of graphs coSpectral to a multicone graph. Additionally, lower and upper bounds for the largest eigenvalue of a multicone graph are given.
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On the Spectral Characterization of theta graphs
Match-communications in Mathematical and in Computer Chemistry, 2009Co-Authors: Jianfeng Wang, Qiongxiang Huang, Francesco Belardo, Enzo M. Li MarziAbstract:The theta-graph, denoted by theta(i,j,k), is a graph consisting of two given vertices joined by three paths whose order is i + 2, j + 2 and k + 2 respectively, with any two of these paths having only the given vertices in common. It is well-know that the problem of Spectral Characterization is related to the Huckel theory from Chemistry. In the paper we will show that the theta-graphs containing odd cycles and without no 4-cycles slid the theta-graphs with minimal Spectral radius are determined by the adjacency spectrum.
Fenjin Liu - One of the best experts on this subject based on the ideXlab platform.
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On the Laplacian Spectral Characterization of Π-shape trees
Indian Journal of Pure and Applied Mathematics, 2018Co-Authors: Fei Wen, Qiongxiang Huang, Xueyi Huang, Fenjin LiuAbstract:A Π-shape tree is a tree with exactly two vertices having the maximum degree three. In this paper, we classify the Π-shape trees into two types, and complete the Spectral Characterization for one type. Exactly, we prove that all graphs of this type are determined by their Laplacian spectra with some exceptions. Moreover, we give some L-coSpectral mates of some graphs for another type.
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Laplacian Spectral Characterization of 3-rose graphs
Linear Algebra and its Applications, 2013Co-Authors: Fenjin Liu, Qiongxiang HuangAbstract:Abstract A 3 -rose graph is a graph consisting of three cycles intersecting in a common vertex, J. Wang et al. showed all 3-rose graphs with at least one triangle are determined by their Laplacian spectra. In this paper, we complete the above Laplacian Spectral Characterization and prove that all 3-rose graphs are determined by their Laplacian spectra.
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On the Spectral Characterization of Π-shape trees
Linear and Multilinear Algebra, 2013Co-Authors: Fenjin Liu, Qiongxiang HuangAbstract:A Π-shape tree is a tree with exactly two of its vertices having the maximum degree 3. In this article, we classify the Π-shape trees into six types according to the number of their closed walks of length 6. Then we complete the Spectral Characterization for one type. We show that all graphs of one such type are determined by the spectrum. Another type i.e., W n is known to have the unique coSpectral mate C 4 ∪ P n . Moreover, we find coSpectral graphs of some graphs for the remaining four types.
Xiaoxiong Xiong - One of the best experts on this subject based on the ideXlab platform.
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Terra and Aqua MODIS on-orbit Spectral Characterization for reflective solar bands
Ocean Sensing and Monitoring V, 2013Co-Authors: Taeyoung Choi, Xiaoxiong Xiong, Zhipeng Wang, Daniel LinkAbstract:The MODerate resolution Imaging Spectroradiometers (MODIS) onboard the NASA EOS Terra and Aqua spacecraft were launched on December 18, 1999 and May 4, 2002 respectively. They have both successfully operated on-orbit for more than a decade. The Spectral characteristics of the MODIS instruments were calibrated pre-launch using a ground calibration device called the Spectral Measurement Assembly (SpMA). The ground Spectral Characterization was transferred to an on-board device called the Spectro-Radiometric Calibration Assembly (SRCA) for the Reflective Solar Bands (RSB) by measuring the sensor Spectral responses near simultaneously with both SRCA and SpMA. After transferring the calibration reference from the SpMA, the SRCA was able to track the on-orbit Spectral changes by performing periodic Spectral mode operations. This paper provides brief descriptions of MODIS on-orbit Spectral Characterization via its on-board SRCA. In the algorithm description section, functional steps and Spectral calibration methodologies are presented. This study will focus on MODIS SWIR bands (bands 5, 6, 7 and 26) as their center wavelengths are longer than 1μm, which is beyond the specified SRCA Spectral calibration range. In addition to the SWIR bands, band 2 results are also included. Because of the pre-launch and on-orbit configuration differences, band 2 Spectral Characterization is referenced to the first onorbit results. A summary of Terra and Aqua MODIS on-orbit relative Spectral response changes, such as center wavelength and bandwidth changes, is provided in this paper for all the RSB bands.
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Results and lessons from a decade of Terra MODIS on-orbit Spectral Characterization
Earth Observing Missions and Sensors: Development Implementation and Characterization, 2010Co-Authors: Xiaoxiong Xiong, Nianzeng Che, Taeyoung Choi, Zhipeng Wang, Yong Xie, Jennifer Dodd, William L. BarnesAbstract:Since launch in 1999, the NASA EOS Terra MODIS has successfully operated for more than a decade. MODIS acquires data in 36 Spectral bands with wavelengths ranging from visible (VIS) to long-wave infrared (LWIR) and at three nadir spatial resolutions: 250m for 2 bands, 500m for 5 bands, and 1km for 29 bands. In addition to its on-board calibrators (OBC), designed for sensor radiometric calibration and Characterization, MODIS was built with a unique device called the spectro-radiometric calibration assembly (SRCA), which can be configured into three different modes: radiometric, spatial, and Spectral. When it is operated in the Spectral mode, the SRCA can monitor changes in sensor Spectral performance for the VIS and near-infrared (NIR) Spectral bands. For more than 10 years, the SRCA operations have continued to provide valuable information for Terra MODIS on-orbit Spectral performance. This paper briefly describes Terra MODIS SRCA on-orbit operations and calibration activities and presents results derived from its decade-long Spectral Characterization, including changes in the VIS and NIR Spectral bands center wavelengths (CW) and bandwidths (BW). It demonstrates that the SRCA on-orbit wavelength calibration capability remains satisfactory. For most Spectral bands, the changes in CW and BW are less than 0.5 nm and 1.0 nm, respectively. As expected, results and lessons from Terra MODIS on-orbit Spectral Characterization have and will continue to benefit the operation and calibration of its successor, Aqua MODIS, and the development of future missions and sensors, which have stringent requirements on sensor Spectral performance.
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Uncertainty analysis of Terra MODIS on-orbit Spectral Characterization
Earth Observing Systems XI, 2006Co-Authors: Yong Xie, Xiaoxiong Xiong, Nianzeng CheAbstract:MODerate resolution Imaging Spectro-radiometer (MODIS) has been operated on-board the Terra spacecraft since December 18, 1999 and Aqua MODIS since May 4, 2002. Both MODIS Relative Solar Bands (RSBs) and Thermal Emissive Bands (TEBs) are calibrated on-orbit by a set of on-board calibrations (OBCs) in radiometric, spatial and Spectral modes, providing accurate measurements for scientific researches. The Spectro-Radiometric Calibration Assembly (SRCA) is one of the key OBCs which can be operated at all three calibration modes. When operating in Spectral mode, the SRCA is utilized for MODIS On-Orbit Spectral Characterization (MOOSC), monitoring and measuring the center wavelength (CW) shift of each RSB throughout the entire mission. However, some uncertainties in the SRCA measurement may affect the precision of the results due to possible system degradation, mechanical/optical backlash, deformation, and optical performance change. In this study, the instrument background and the algorithm for calculating the CW shift of RSBs using the SRCA measurements are briefly introduced. We analyze or estimate the impact on the final CW value caused by the uncertainties on the Terra MODIS on-orbit Spectral Characterizations, including cavity temperature variation, limited number of sample points, noise of background, and the variation of β and θ off . The results show that the influence is small and the maximum uncertainty is less than 1nm. The lessons we learned in this study provide helpful information and experiences for the sensors which have no on-orbit Spectral Characterization capability and the useful guidance for the next generation satellite remote sensors.
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Five years of Terra MODIS on-orbit Spectral Characterization
Earth Observing Systems X, 2005Co-Authors: Xiaoxiong Xiong, Nianzeng Che, B. Guenther, W. Barnes, Vincent V. SalomonsonAbstract:The Moderate Resolution Imaging Spectroradiometer (MODIS) is one of the five Earth-observing instruments onboard the NASA EOS Terra spacecraft launched in December 1999. It makes frequent global observations over a broad Spectral range (0.41 to 14.4μ) and at three spatial resolutions (0.25km, 0.5km, and 1km at nadir). The MODIS was designed with a set of on-board calibrators (OBCs) that include a solar diffuser (SD), a blackbody (BB), and spectro-radiometric calibration assembly (SRCA). One SRCA function is to provide on-orbit Spectral Characterization of the MODIS reflective solar bands (RSB) with wavelengths from 0.41 to 2.2μ. This paper provides an overview of the MODIS SRCA on-orbit Spectral Characterization approach and summarizes the results derived from five years of Terra MODIS on-orbit observations. In general, the on-orbit Characterization of the Terra MODIS RSB relative Spectral responses (RSR) has been satisfactory. The measured center wavelength (CW) shifts are less than 0.6nm for the 412nm Spectral band, 0.5nm for the 443nm band, and 0.4nm for the remaining reflective solar bands (short-wave infrared bands excluded). The bandwidth (BW) changes are typically less than 1nm. Excluding the differences between pre-launch and initial on-orbit results, the CW shifts and BW changes are very stable. For a given band, the detector-to-detector Spectral Characterization differences are typically less than 0.2nm.
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On-orbit Spectral Characterization results for of the Terra MODIS reflective solar bands
Earth Observing Systems VIII, 2003Co-Authors: Nianzeng Che, Xiaoxiong Xiong, William L. BarnesAbstract:The MODIS Protoflight Model (PFM), launched onboard the NASA s Earth Observing System (EOS) Terra spacecraft, has been in operation for more than three years. In addition to constant radiometric calibration activities, the sensor s on-orbit Spectral bandpasses of the reflective solar bands (RSBs) with wavelengths from 0.41 to 2.2 micrometers have been measured (every three months) using the on-board Spectral Radiometric Calibration Assembly (SRCA). The Spectral characteristics of the SRCA were calibrated pre-launch using the Spectral Measurement Assembly (SpMA). The MODIS on-orbit Spectral Characterization using the SRCA has been performing as designed and the key Spectral parameters, with few exceptions, are well within the specification limits. This paper provides a brief review of the MODIS prelaunch Spectral Characterization. It focuses on the Terra MODIS instrument s on-orbit Spectral Characterization activities, trending results, and comparisons with pre-launch Characterizations and the specifications.
Nianzeng Che - One of the best experts on this subject based on the ideXlab platform.
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Results and lessons from a decade of Terra MODIS on-orbit Spectral Characterization
Earth Observing Missions and Sensors: Development Implementation and Characterization, 2010Co-Authors: Xiaoxiong Xiong, Nianzeng Che, Taeyoung Choi, Zhipeng Wang, Yong Xie, Jennifer Dodd, William L. BarnesAbstract:Since launch in 1999, the NASA EOS Terra MODIS has successfully operated for more than a decade. MODIS acquires data in 36 Spectral bands with wavelengths ranging from visible (VIS) to long-wave infrared (LWIR) and at three nadir spatial resolutions: 250m for 2 bands, 500m for 5 bands, and 1km for 29 bands. In addition to its on-board calibrators (OBC), designed for sensor radiometric calibration and Characterization, MODIS was built with a unique device called the spectro-radiometric calibration assembly (SRCA), which can be configured into three different modes: radiometric, spatial, and Spectral. When it is operated in the Spectral mode, the SRCA can monitor changes in sensor Spectral performance for the VIS and near-infrared (NIR) Spectral bands. For more than 10 years, the SRCA operations have continued to provide valuable information for Terra MODIS on-orbit Spectral performance. This paper briefly describes Terra MODIS SRCA on-orbit operations and calibration activities and presents results derived from its decade-long Spectral Characterization, including changes in the VIS and NIR Spectral bands center wavelengths (CW) and bandwidths (BW). It demonstrates that the SRCA on-orbit wavelength calibration capability remains satisfactory. For most Spectral bands, the changes in CW and BW are less than 0.5 nm and 1.0 nm, respectively. As expected, results and lessons from Terra MODIS on-orbit Spectral Characterization have and will continue to benefit the operation and calibration of its successor, Aqua MODIS, and the development of future missions and sensors, which have stringent requirements on sensor Spectral performance.
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Uncertainty analysis of Terra MODIS on-orbit Spectral Characterization
Earth Observing Systems XI, 2006Co-Authors: Yong Xie, Xiaoxiong Xiong, Nianzeng CheAbstract:MODerate resolution Imaging Spectro-radiometer (MODIS) has been operated on-board the Terra spacecraft since December 18, 1999 and Aqua MODIS since May 4, 2002. Both MODIS Relative Solar Bands (RSBs) and Thermal Emissive Bands (TEBs) are calibrated on-orbit by a set of on-board calibrations (OBCs) in radiometric, spatial and Spectral modes, providing accurate measurements for scientific researches. The Spectro-Radiometric Calibration Assembly (SRCA) is one of the key OBCs which can be operated at all three calibration modes. When operating in Spectral mode, the SRCA is utilized for MODIS On-Orbit Spectral Characterization (MOOSC), monitoring and measuring the center wavelength (CW) shift of each RSB throughout the entire mission. However, some uncertainties in the SRCA measurement may affect the precision of the results due to possible system degradation, mechanical/optical backlash, deformation, and optical performance change. In this study, the instrument background and the algorithm for calculating the CW shift of RSBs using the SRCA measurements are briefly introduced. We analyze or estimate the impact on the final CW value caused by the uncertainties on the Terra MODIS on-orbit Spectral Characterizations, including cavity temperature variation, limited number of sample points, noise of background, and the variation of β and θ off . The results show that the influence is small and the maximum uncertainty is less than 1nm. The lessons we learned in this study provide helpful information and experiences for the sensors which have no on-orbit Spectral Characterization capability and the useful guidance for the next generation satellite remote sensors.
-
Five years of Terra MODIS on-orbit Spectral Characterization
Earth Observing Systems X, 2005Co-Authors: Xiaoxiong Xiong, Nianzeng Che, B. Guenther, W. Barnes, Vincent V. SalomonsonAbstract:The Moderate Resolution Imaging Spectroradiometer (MODIS) is one of the five Earth-observing instruments onboard the NASA EOS Terra spacecraft launched in December 1999. It makes frequent global observations over a broad Spectral range (0.41 to 14.4μ) and at three spatial resolutions (0.25km, 0.5km, and 1km at nadir). The MODIS was designed with a set of on-board calibrators (OBCs) that include a solar diffuser (SD), a blackbody (BB), and spectro-radiometric calibration assembly (SRCA). One SRCA function is to provide on-orbit Spectral Characterization of the MODIS reflective solar bands (RSB) with wavelengths from 0.41 to 2.2μ. This paper provides an overview of the MODIS SRCA on-orbit Spectral Characterization approach and summarizes the results derived from five years of Terra MODIS on-orbit observations. In general, the on-orbit Characterization of the Terra MODIS RSB relative Spectral responses (RSR) has been satisfactory. The measured center wavelength (CW) shifts are less than 0.6nm for the 412nm Spectral band, 0.5nm for the 443nm band, and 0.4nm for the remaining reflective solar bands (short-wave infrared bands excluded). The bandwidth (BW) changes are typically less than 1nm. Excluding the differences between pre-launch and initial on-orbit results, the CW shifts and BW changes are very stable. For a given band, the detector-to-detector Spectral Characterization differences are typically less than 0.2nm.
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On-orbit Spectral Characterization results for of the Terra MODIS reflective solar bands
Earth Observing Systems VIII, 2003Co-Authors: Nianzeng Che, Xiaoxiong Xiong, William L. BarnesAbstract:The MODIS Protoflight Model (PFM), launched onboard the NASA s Earth Observing System (EOS) Terra spacecraft, has been in operation for more than three years. In addition to constant radiometric calibration activities, the sensor s on-orbit Spectral bandpasses of the reflective solar bands (RSBs) with wavelengths from 0.41 to 2.2 micrometers have been measured (every three months) using the on-board Spectral Radiometric Calibration Assembly (SRCA). The Spectral characteristics of the SRCA were calibrated pre-launch using the Spectral Measurement Assembly (SpMA). The MODIS on-orbit Spectral Characterization using the SRCA has been performing as designed and the key Spectral parameters, with few exceptions, are well within the specification limits. This paper provides a brief review of the MODIS prelaunch Spectral Characterization. It focuses on the Terra MODIS instrument s on-orbit Spectral Characterization activities, trending results, and comparisons with pre-launch Characterizations and the specifications.
William L. Barnes - One of the best experts on this subject based on the ideXlab platform.
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Results and lessons from a decade of Terra MODIS on-orbit Spectral Characterization
Earth Observing Missions and Sensors: Development Implementation and Characterization, 2010Co-Authors: Xiaoxiong Xiong, Nianzeng Che, Taeyoung Choi, Zhipeng Wang, Yong Xie, Jennifer Dodd, William L. BarnesAbstract:Since launch in 1999, the NASA EOS Terra MODIS has successfully operated for more than a decade. MODIS acquires data in 36 Spectral bands with wavelengths ranging from visible (VIS) to long-wave infrared (LWIR) and at three nadir spatial resolutions: 250m for 2 bands, 500m for 5 bands, and 1km for 29 bands. In addition to its on-board calibrators (OBC), designed for sensor radiometric calibration and Characterization, MODIS was built with a unique device called the spectro-radiometric calibration assembly (SRCA), which can be configured into three different modes: radiometric, spatial, and Spectral. When it is operated in the Spectral mode, the SRCA can monitor changes in sensor Spectral performance for the VIS and near-infrared (NIR) Spectral bands. For more than 10 years, the SRCA operations have continued to provide valuable information for Terra MODIS on-orbit Spectral performance. This paper briefly describes Terra MODIS SRCA on-orbit operations and calibration activities and presents results derived from its decade-long Spectral Characterization, including changes in the VIS and NIR Spectral bands center wavelengths (CW) and bandwidths (BW). It demonstrates that the SRCA on-orbit wavelength calibration capability remains satisfactory. For most Spectral bands, the changes in CW and BW are less than 0.5 nm and 1.0 nm, respectively. As expected, results and lessons from Terra MODIS on-orbit Spectral Characterization have and will continue to benefit the operation and calibration of its successor, Aqua MODIS, and the development of future missions and sensors, which have stringent requirements on sensor Spectral performance.
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On-orbit Spectral Characterization results for of the Terra MODIS reflective solar bands
Earth Observing Systems VIII, 2003Co-Authors: Nianzeng Che, Xiaoxiong Xiong, William L. BarnesAbstract:The MODIS Protoflight Model (PFM), launched onboard the NASA s Earth Observing System (EOS) Terra spacecraft, has been in operation for more than three years. In addition to constant radiometric calibration activities, the sensor s on-orbit Spectral bandpasses of the reflective solar bands (RSBs) with wavelengths from 0.41 to 2.2 micrometers have been measured (every three months) using the on-board Spectral Radiometric Calibration Assembly (SRCA). The Spectral characteristics of the SRCA were calibrated pre-launch using the Spectral Measurement Assembly (SpMA). The MODIS on-orbit Spectral Characterization using the SRCA has been performing as designed and the key Spectral parameters, with few exceptions, are well within the specification limits. This paper provides a brief review of the MODIS prelaunch Spectral Characterization. It focuses on the Terra MODIS instrument s on-orbit Spectral Characterization activities, trending results, and comparisons with pre-launch Characterizations and the specifications.
