The Experts below are selected from a list of 127281 Experts worldwide ranked by ideXlab platform
Hiroyuki Oguma - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of DSMs generated from multi-temporal aerial photographs using Emerging Structure from motion–multi-view stereo technology
Geomorphology, 2016Co-Authors: Satoshi Ishiguro, Hiroya Yamano, Hiroyuki OgumaAbstract:Abstract An accuracy assessment of digital surface models (DSMs) generated from archived aerial photographs using the Structure from motion–multi-view stereo (SfM–MVS) technique was carried out. A four-step accuracy-assessment procedure was adopted using aerial photography from eight periods, as follows. Step 1: generate a DSM and orthophoto from digital aerial photographs taken in 2013 and ground control points (GCPs) measured by GNSS. Step 2: assess the accuracy of the DSM by comparison with altitude measured by leveling survey. Step 3: generate other historical DSMs and orthophotos from historical aerial photographs using GCPs extracted from the DSM of 2013. Step 4: assess the accuracy of all historical DSMs by comparing with the leveling survey. Then re-calculate the accuracy of historical DSMs by reducing the inherent error in the 2013 DSM. The DSM based on the aerial photographs taken in 2013 was generated with a resolution of 48.2 cm. The residual height error of the GCPs was 15.4 cm. Validation against the altitudes of 171 points revealed that this DSM has a height root-mean-square-error ( RMSE ) of 24.1 cm and is 9.2 cm lower than the leveling data on average. Even using US military photos with unconfirmed detailed specifications, the model can measure the altitude with an RMSE value of 121.5 cm. It appears therefore that analysis by SfM–MVS can give comparable measurement accuracy to traditional aerial photogrammetry. The low cost and high accuracy obtained with archived aerial photographs are worthy of special mention.
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evaluation of dsms generated from multi temporal aerial photographs using Emerging Structure from motion multi view stereo technology
Geomorphology, 2016Co-Authors: Satoshi Ishiguro, Hiroya Yamano, Hiroyuki OgumaAbstract:Abstract An accuracy assessment of digital surface models (DSMs) generated from archived aerial photographs using the Structure from motion–multi-view stereo (SfM–MVS) technique was carried out. A four-step accuracy-assessment procedure was adopted using aerial photography from eight periods, as follows. Step 1: generate a DSM and orthophoto from digital aerial photographs taken in 2013 and ground control points (GCPs) measured by GNSS. Step 2: assess the accuracy of the DSM by comparison with altitude measured by leveling survey. Step 3: generate other historical DSMs and orthophotos from historical aerial photographs using GCPs extracted from the DSM of 2013. Step 4: assess the accuracy of all historical DSMs by comparing with the leveling survey. Then re-calculate the accuracy of historical DSMs by reducing the inherent error in the 2013 DSM. The DSM based on the aerial photographs taken in 2013 was generated with a resolution of 48.2 cm. The residual height error of the GCPs was 15.4 cm. Validation against the altitudes of 171 points revealed that this DSM has a height root-mean-square-error ( RMSE ) of 24.1 cm and is 9.2 cm lower than the leveling data on average. Even using US military photos with unconfirmed detailed specifications, the model can measure the altitude with an RMSE value of 121.5 cm. It appears therefore that analysis by SfM–MVS can give comparable measurement accuracy to traditional aerial photogrammetry. The low cost and high accuracy obtained with archived aerial photographs are worthy of special mention.
T.r.k. Chetty - One of the best experts on this subject based on the ideXlab platform.
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SIGNIFICANCE OF THE BLOCK ROTATION MODEL IN TECTONICS AND MINERALIZATION IN PRECAMBRIAN TERRAINS AN EXAMPLE FROM THE SOUTH INDIAN SHIELD
Journal of Geodynamics, 1995Co-Authors: T.r.k. ChettyAbstract:Abstract Examination of LANDSAT TM-data, for the Archean granite-greenstone-gneiss terrain west of the Proterozoic Cuddapah basin in the southern part of the Indian shield, and of the aerial photographs for a part thereof, provides significant additional information for the region. The Emerging Structure could best be described as the result of a generation of a mosaic of blocks in the early stages of evolution of the greenstone belts and of rotation of these blocks through subsequent geological time.
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Significance of the block rotation model in tectonics and mineralization in Precambrian terrains—An example from the South Indian shield
Journal of Geodynamics, 1995Co-Authors: T.r.k. ChettyAbstract:Abstract Examination of LANDSAT TM-data, for the Archean granite-greenstone-gneiss terrain west of the Proterozoic Cuddapah basin in the southern part of the Indian shield, and of the aerial photographs for a part thereof, provides significant additional information for the region. The Emerging Structure could best be described as the result of a generation of a mosaic of blocks in the early stages of evolution of the greenstone belts and of rotation of these blocks through subsequent geological time.
Satoshi Ishiguro - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of DSMs generated from multi-temporal aerial photographs using Emerging Structure from motion–multi-view stereo technology
Geomorphology, 2016Co-Authors: Satoshi Ishiguro, Hiroya Yamano, Hiroyuki OgumaAbstract:Abstract An accuracy assessment of digital surface models (DSMs) generated from archived aerial photographs using the Structure from motion–multi-view stereo (SfM–MVS) technique was carried out. A four-step accuracy-assessment procedure was adopted using aerial photography from eight periods, as follows. Step 1: generate a DSM and orthophoto from digital aerial photographs taken in 2013 and ground control points (GCPs) measured by GNSS. Step 2: assess the accuracy of the DSM by comparison with altitude measured by leveling survey. Step 3: generate other historical DSMs and orthophotos from historical aerial photographs using GCPs extracted from the DSM of 2013. Step 4: assess the accuracy of all historical DSMs by comparing with the leveling survey. Then re-calculate the accuracy of historical DSMs by reducing the inherent error in the 2013 DSM. The DSM based on the aerial photographs taken in 2013 was generated with a resolution of 48.2 cm. The residual height error of the GCPs was 15.4 cm. Validation against the altitudes of 171 points revealed that this DSM has a height root-mean-square-error ( RMSE ) of 24.1 cm and is 9.2 cm lower than the leveling data on average. Even using US military photos with unconfirmed detailed specifications, the model can measure the altitude with an RMSE value of 121.5 cm. It appears therefore that analysis by SfM–MVS can give comparable measurement accuracy to traditional aerial photogrammetry. The low cost and high accuracy obtained with archived aerial photographs are worthy of special mention.
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evaluation of dsms generated from multi temporal aerial photographs using Emerging Structure from motion multi view stereo technology
Geomorphology, 2016Co-Authors: Satoshi Ishiguro, Hiroya Yamano, Hiroyuki OgumaAbstract:Abstract An accuracy assessment of digital surface models (DSMs) generated from archived aerial photographs using the Structure from motion–multi-view stereo (SfM–MVS) technique was carried out. A four-step accuracy-assessment procedure was adopted using aerial photography from eight periods, as follows. Step 1: generate a DSM and orthophoto from digital aerial photographs taken in 2013 and ground control points (GCPs) measured by GNSS. Step 2: assess the accuracy of the DSM by comparison with altitude measured by leveling survey. Step 3: generate other historical DSMs and orthophotos from historical aerial photographs using GCPs extracted from the DSM of 2013. Step 4: assess the accuracy of all historical DSMs by comparing with the leveling survey. Then re-calculate the accuracy of historical DSMs by reducing the inherent error in the 2013 DSM. The DSM based on the aerial photographs taken in 2013 was generated with a resolution of 48.2 cm. The residual height error of the GCPs was 15.4 cm. Validation against the altitudes of 171 points revealed that this DSM has a height root-mean-square-error ( RMSE ) of 24.1 cm and is 9.2 cm lower than the leveling data on average. Even using US military photos with unconfirmed detailed specifications, the model can measure the altitude with an RMSE value of 121.5 cm. It appears therefore that analysis by SfM–MVS can give comparable measurement accuracy to traditional aerial photogrammetry. The low cost and high accuracy obtained with archived aerial photographs are worthy of special mention.
Nigel J. Pyne - One of the best experts on this subject based on the ideXlab platform.
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sphingosine kinases Emerging Structure function insights
Trends in Biochemical Sciences, 2016Co-Authors: David R. Adams, Susan Pyne, Nigel J. PyneAbstract:Sphingosine kinases (SK1 and SK2) catalyse the conversion of sphingosine into sphingosine 1-phosphate and control fundamental cellular processes, including cell survival, proliferation, differentiation, migration, and immune function. In this review, we highlight recent breakthroughs in the structural and functional characterisation of SK1 and these are contextualised by analysis of crystal Structures for closely related prokaryotic lipid kinases. We identify a putative dimerisation interface and propose novel regulatory mechanisms governing structural plasticity induced by phosphorylation and interaction with phospholipids and proteins. Our analysis suggests that the catalytic function and regulation of the enzymes might be dependent on conformational mobility and it provides a roadmap for future interrogation of SK1 function and its role in physiology and disease.
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Sphingosine Kinases: Emerging Structure–Function Insights
Trends in Biochemical Sciences, 2016Co-Authors: David R. Adams, Susan Pyne, Nigel J. PyneAbstract:Sphingosine kinases (SK1 and SK2) catalyse the conversion of sphingosine into sphingosine 1-phosphate and control fundamental cellular processes, including cell survival, proliferation, differentiation, migration, and immune function. In this review, we highlight recent breakthroughs in the structural and functional characterisation of SK1 and these are contextualised by analysis of crystal Structures for closely related prokaryotic lipid kinases. We identify a putative dimerisation interface and propose novel regulatory mechanisms governing structural plasticity induced by phosphorylation and interaction with phospholipids and proteins. Our analysis suggests that the catalytic function and regulation of the enzymes might be dependent on conformational mobility and it provides a roadmap for future interrogation of SK1 function and its role in physiology and disease.
Uma Narayanasami - One of the best experts on this subject based on the ideXlab platform.
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roles of heparan sulphate glycosaminoglycans in cancer
Nature Reviews Cancer, 2002Co-Authors: Ram Sasisekharan, Zachary Shriver, Ganesh Venkataraman, Uma NarayanasamiAbstract:Cell-surface/extracellular-matrix heparan-sulphate glycosaminoglycans (HSGAGs) are complex polysaccharides that are ubiquitous in nature, and that regulate several aspects of cancer biology, including tumorigenesis, tumour progression and metastasis. Recently gained insights into the Structure of HSGAGs have extended our understanding of their role in the oncogenic process. At present, clinical trials are examining the anticancer properties of exogenous highly sulphated HSGAGs, including heparin and low-molecular-weight heparins, in addition to small oligosaccharide heparin mimetics. Combined with our more intricate understanding of HSGAG Structure, this Emerging Structure–activity approach opens exciting avenues for the generation of polysaccharide-based anticancer therapeutics.
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Roles of heparan-sulphate glycosaminoglycans in cancer
Nature Reviews Cancer, 2002Co-Authors: Ram Sasisekharan, Zachary Shriver, Ganesh Venkataraman, Uma NarayanasamiAbstract:Cell-surface/extracellular-matrix heparan-sulphate glycosaminoglycans (HSGAGs) are complex polysaccharides that are ubiquitous in nature, and that regulate several aspects of cancer biology, including tumorigenesis, tumour progression and metastasis. Recently gained insights into the Structure of HSGAGs have extended our understanding of their role in the oncogenic process. At present, clinical trials are examining the anticancer properties of exogenous highly sulphated HSGAGs, including heparin and low-molecular-weight heparins, in addition to small oligosaccharide heparin mimetics. Combined with our more intricate understanding of HSGAG Structure, this Emerging Structure–activity approach opens exciting avenues for the generation of polysaccharide-based anticancer therapeutics. Heparan-sulphate glycosaminoglycans (HSGAGs) act at the cell–extracellular-matrix (ECM) interface to modulate cell signalling, thereby regulating how a cell perceives its environment. HSGAGs interact with various extracellular signalling molecules: growth factors, morphogens, enzymes and chemokines. The specificity of these interactions is dependent on HSGAG sequence, spacing of binding sites and the three-dimensional Structure of the HSGAG chain. HSGAGs, depending on location and sequence, impinge on tumour onset and progression in various ways, some of which are pro-tumorigenic and others of which are anti-tumorigenic. HSGAGs at the tumour-cell surface actively modulate the tumorigenic process by regulating autocrine signalling loops that lead to unregulated cell growth. HSGAGs impinge on how an organism responds to a growing tumour, including the recruitment of cells of the immune system to the tumour site, formation of a fibrin shell around the tumour that acts as a protective barrier and development of new blood vessels to the site of the growing tumour. Compelling clinical evidence indicates that pharmacological doses of heparin, a highly sulphated HSGAG, can have a marked effect on tumour metastasis. Clinical trials have been designed to determine the exact benefits of heparin therapy in cancer. In addition, the low-molecular-weight heparins (LMWHs) — a series of heparin fragments that share many of heparin's activities, including its anticoagulant effect, but lack several of its side effects — might show even greater antitumour activity. The advent of HSGAG sequencing technologies promises to usher in a new generation of LMWHs with potent antitumour activity.