Land-use/land-cover changes （LUCCs） have links to both human and nature inter- actions. China＇s Land-Use/cover Datasets （CLUDs） were updated regularly at 5-year inter- vals from the late 1980s to 2010, with stand...Land-use/land-cover changes （LUCCs） have links to both human and nature inter- actions. China＇s Land-Use/cover Datasets （CLUDs） were updated regularly at 5-year inter- vals from the late 1980s to 2010, with standard procedures based on Landsat TM／ETM＋ im- ages. A land-use dynamic regionalization method was proposed to analyze major land-use conversions. The spatiotemporal characteristics, differences, and causes of land-use changes at a national scale were then examined. The main findings are summarized as fol- lows. Land-use changes （LUCs） across China indicated a significant variation in spatial and temporal characteristics in the last 20 years （1990-2010）. The area of cropland change de- creased in the south and increased in the north, but the total area remained almost un- changed. The reclaimed cropland was shifted from the northeast to the northwest. The built-up lands expanded rapidly, were mainly distributed in the east, and gradually spread out to central and western China. Woodland decreased first, and then increased, but desert area was the opposite. Grassland continued decreasing. Different spatial patterns of LUC in China were found between the late 20th century and the early 21st century. The original 13 LUC zones were replaced by 15 units with changes of boundaries in some zones. The main spatial characteristics of these changes included （1） an accelerated expansion of built-up land in the Huang-Huai-Hai region, the southeastern coastal areas, the midstream area of the Yangtze River, and the Sichuan Basin; （2） shifted land reclamation in the north from northeast China and eastern Inner Mongolia to the oasis agricultural areas in northwest China; （3） continuous transformation from rain-fed farmlands in northeast China to paddy fields; and （4） effective- ness of the ＂Grain for Green＂ project in the southern agricultural-pastoral ecotones of Inner Mongolia, the Loess Plateau, and southwestern mountainous areas. In the last two decades, although climate change展开更多
The irregular domain and lack of ordering make it challenging to design deep neural networks for point cloud processing.This paper presents a novel framework named Point Cloud Transformer(PCT)for point cloud learning....The irregular domain and lack of ordering make it challenging to design deep neural networks for point cloud processing.This paper presents a novel framework named Point Cloud Transformer(PCT)for point cloud learning.PCT is based on Transformer,which achieves huge success in natural language processing and displays great potential in image processing.It is inherently permutation invariant for processing a sequence of points,making it well-suited for point cloud learning.To better capture local context within the point cloud,we enhance input embedding with the support of farthest point sampling and nearest neighbor search.Extensive experiments demonstrate that the PCT achieves the state-of-the-art performance on shape classification,part segmentation,semantic segmentation,and normal estimation tasks.展开更多
Humans can naturally and effectively find salient regions in complex scenes.Motivated by this observation,attention mechanisms were introduced into computer vision with the aim of imitating this aspect of the human vi...Humans can naturally and effectively find salient regions in complex scenes.Motivated by this observation,attention mechanisms were introduced into computer vision with the aim of imitating this aspect of the human visual system.Such an attention mechanism can be regarded as a dynamic weight adjustment process based on features of the input image.Attention mechanisms have achieved great success in many visual tasks,including image classification,object detection,semantic segmentation,video understanding,image generation,3D vision,multimodal tasks,and self-supervised learning.In this survey,we provide a comprehensive review of various attention mechanisms in computer vision and categorize them according to approach,such as channel attention,spatial attention,temporal attention,and branch attention;a related repository https://github.com/MenghaoG uo/Awesome-Vision-Attentions is dedicated to collecting related work.We also suggest future directions for attention mechanism research.展开更多
The long-term goal of artificial intelligence （AI） is to make machines learn and think like human beings. Due to the high levels of uncertainty and vulnerability in human life and the open-ended nature of problems t...The long-term goal of artificial intelligence （AI） is to make machines learn and think like human beings. Due to the high levels of uncertainty and vulnerability in human life and the open-ended nature of problems that humans are facing, no matter how intelligent machines are, they are unable to completely replace humans. Therefore, it is necessary to introduce human cognitive capabilities or human-like cognitive models into AI systems to develop a new form of AI, that is, hybrid-augmented intelligence. This form of AI or machine intelligence is a feasible and important developing model. Hybrid-augmented intelligence can be divided into two basic models： one is human-in-the-loop augmented intelligence with human-computer collaboration, and the other is cognitive computing based augmented intelligence, in which a cognitive model is embedded in the machine learning system. This survey describes a basic framework for human-computer collaborative hybrid-augmented intelligence, and the basic elements of hybrid-augmented intelligence based on cognitive computing. These elements include intuitive reasoning, causal models, evolution of memory and knowledge, especially the role and basic principles of intuitive reasoning for complex problem solving, and the cognitive learning framework for visual scene understanding based on memory and reasoning. Several typical applications of hybrid-augmented intelligence in related fields are given.展开更多
Vascular smooth muscle cell （VSMC） differentiation and proliferation are two important physiological proc- esses during vascular development. The phenotypic alteration from differentiated to proliferative VSMC contr...Vascular smooth muscle cell （VSMC） differentiation and proliferation are two important physiological proc- esses during vascular development. The phenotypic alteration from differentiated to proliferative VSMC contrib- utes to the development of several major cardiovascular diseases including atherosclerosis, hypertension, resteno- sis after angioplasty or bypass, diabetic vascular complications, and transplantation arteriopathy. Since the VSMC phenotype in these pathological conditions resembles that of developing VSMC during embryonic development, understanding of the molecular mechanisms that control VSMC differentiation will provide fundamental insights into the pathological processes of these cardiovascular diseases. Although VSMC differentiation is usually ac- companied by an irreversible cell cycle exit, VSMC proliferation and differentiation occur concurrently during embryonic development. The molecular mechanisms simultaneously regulating these two processes, however, remain largely unknown. Our recent study demonstrates that cell division cycle 7, a key regulator of cell cycle, promotes both VSMC differentiation and proliferation through different mechanisms during the initial phase of VSMC differentiation. Conversely, Kriappel-like factor 4 appears to be a repressor for both VSMC differentia- tion and proliferation. This review attempts to highlight the novel role of cell division cycle 7 in TGF-β-induced VSMC differentiation and proliferation. The role of K141ppel-like factor 4 in suppressing these two processes will also be discussed.展开更多
Convection in a horizontal fluid layer heated from below is one of models for studying patterns of convection in binary fluid mixtures and has been extensively studied. In this article, the convection structures in a ...Convection in a horizontal fluid layer heated from below is one of models for studying patterns of convection in binary fluid mixtures and has been extensively studied. In this article, the convection structures in a rectangular cell were investigated for the aspect-ratio Г= 12 and the separation ratio ψ = -0.47. Simulations were preformed by solving the hydrodynamic equations using the SIMPLE method. A Counter Propagating Wave （CPW） state was found in binary fluid convection with a periodically horizontal motion of defects, and the pattern dynamics was further discuss.展开更多
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) is a special reflecting Schmidt telescope. LAMOST’s special design allows both a large aperture (effecti...The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) is a special reflecting Schmidt telescope. LAMOST’s special design allows both a large aperture (effective aperture of 3.6 m–4.9 m) and a wide field of view (FOV) (5°). It has an innovative active reflecting Schmidt configuration which continuously changes the mirror’s surface that adjusts during the observation process and combines thin deformable mirror active optics with segmented active optics. Its primary mirror (6.67m×6.05 m) and active Schmidt mirror (5.74m×4.40 m) are both segmented, and composed of 37 and 24 hexagonal sub-mirrors respectively. By using a parallel controllable fiber positioning technique, the focal surface of 1.75 m in diameter can accommodate 4000 optical fibers. Also, LAMOST has 16 spectrographs with 32 CCD cameras. LAMOST will be the telescope with the highest rate of spectral acquisition. As a national large scientific project, the LAMOST project was formally proposed in 1996, and approved by the Chinese government in 1997. The construction started in 2001, was completed in 2008 and passed the official acceptance in June 2009. The LAMOST pilot survey was started in October 2011 and the spectroscopic survey will launch in September 2012. Up to now, LAMOST has released more than 480 000 spectra of objects. LAMOST will make an important contribution to the study of the large-scale structure of the Universe, structure and evolution of the Galaxy, and cross-identification of multiwaveband properties in celestial objects.展开更多
The Large sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of ...The Large sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs. Objects in both the pilot survey and the first year regular survey are included in the LAMOST DR1. The pilot survey started in October 2011 and ended in June 2012, and the data have been released to the public as the LAMOST Pilot Data Release in August 2012. The regular survey started in September 2012, and completed its first year of operation in June 2013. The LAMOST DR1 includes a total of 1202 plates containing 2 955 336 spectra, of which 1 790 879 spectra have observed signalto-noise ratio（SNR） ≥ 10. All data with SNR ≥ 2 are formally released as LAMOST DR1 under the LAMOST data policy. This data release contains a total of 2 204 696 spectra, of which 1 944 329 are stellar spectra, 12 082 are galaxy spectra and 5017 are quasars. The DR1 not only includes spectra, but also three stellar catalogs with measured parameters： late A,FGK-type stars with high quality spectra（1 061 918 entries）, A-type stars（100 073 entries）, and M-type stars（121 522 entries）. This paper introduces the survey design, the observational and instrumental limitations, data reduction and analysis, and some caveats. A description of the FITS structure of spectral files and parameter catalogs is also provided.展开更多
background and purpose A multicentre prospective registry study of individually tailored stenting for a patient with symptomatic intracranial atherosclerotic stenosis(ICAS)combined with poor collaterals in China showe...background and purpose A multicentre prospective registry study of individually tailored stenting for a patient with symptomatic intracranial atherosclerotic stenosis(ICAS)combined with poor collaterals in China showed that the short-term safety and efficacy of stenting was acceptable.However,it remained uncertain whether the low event rate could be of a long term.We reported the 1-year outcome of this registry study to evaluate the long-term efficacy of individually tailored stenting for patients with severe symptomatic ICAS combined with poor collaterals.Methods Patients with symptomatic ICAS caused by 70%-99% stenosis located at the intracranial internal carotid,middle cerebral,intracranial vertebral or basilar arteries combined with poor collaterals were enrolled.Balloon-mounted stent or balloon plus self-expanding stent were selected based on the ease of vascular access and lesion morphology determined by the operators.The primary outcome was the rate of 30-day stroke,transient ischaemic attack and death,and 12-month ischaemic stroke within the same vascular territory,haemorrhagic stroke and vascular death after stenting.results From September 2013 to January 2015,300 patients(ages 58.3±9.78 years)were recruited.Among them,159 patients were treated with balloon-mounted stent and 141 with balloon plus self-expanding stent.During the 1-year follow-up,25 patients had a primary end point event.The probability of primary outcome at 1 year was 8.1%(95% CI 5.3% to 11.7%).In 76 patients with digital subtraction angiography follow-up,27.6%(21/76)had re-stenosis≥50% and 18.4%(14/76)had re-stenosis≥70%.No baseline characteristic was associated with the primary outcome.Conclusion The event rate remains low over 1 year of individually tailored stenting for patients with severe symptomatic ICAS combined with poor collaterals.Further randomised trial of comparing individually tailored stenting with best medical therapy is needed.展开更多
基金National Basic Research Program of China,No.2010CB950900No.2014CB954302+1 种基金National Key Technol-ogy R&D Program,No.2013BAC03B00The Key Research Program of the Chinese Academy of Sciences,No.KSZD-EW-Z-021-02
文摘Land-use/land-cover changes （LUCCs） have links to both human and nature inter- actions. China＇s Land-Use/cover Datasets （CLUDs） were updated regularly at 5-year inter- vals from the late 1980s to 2010, with standard procedures based on Landsat TM／ETM＋ im- ages. A land-use dynamic regionalization method was proposed to analyze major land-use conversions. The spatiotemporal characteristics, differences, and causes of land-use changes at a national scale were then examined. The main findings are summarized as fol- lows. Land-use changes （LUCs） across China indicated a significant variation in spatial and temporal characteristics in the last 20 years （1990-2010）. The area of cropland change de- creased in the south and increased in the north, but the total area remained almost un- changed. The reclaimed cropland was shifted from the northeast to the northwest. The built-up lands expanded rapidly, were mainly distributed in the east, and gradually spread out to central and western China. Woodland decreased first, and then increased, but desert area was the opposite. Grassland continued decreasing. Different spatial patterns of LUC in China were found between the late 20th century and the early 21st century. The original 13 LUC zones were replaced by 15 units with changes of boundaries in some zones. The main spatial characteristics of these changes included （1） an accelerated expansion of built-up land in the Huang-Huai-Hai region, the southeastern coastal areas, the midstream area of the Yangtze River, and the Sichuan Basin; （2） shifted land reclamation in the north from northeast China and eastern Inner Mongolia to the oasis agricultural areas in northwest China; （3） continuous transformation from rain-fed farmlands in northeast China to paddy fields; and （4） effective- ness of the ＂Grain for Green＂ project in the southern agricultural-pastoral ecotones of Inner Mongolia, the Loess Plateau, and southwestern mountainous areas. In the last two decades, although climate change
基金supported by the National Natural Science Foundation of China(Project Number 61521002)the Joint NSFC–DFG Research Program(Project Number 61761136018).
文摘The irregular domain and lack of ordering make it challenging to design deep neural networks for point cloud processing.This paper presents a novel framework named Point Cloud Transformer(PCT)for point cloud learning.PCT is based on Transformer,which achieves huge success in natural language processing and displays great potential in image processing.It is inherently permutation invariant for processing a sequence of points,making it well-suited for point cloud learning.To better capture local context within the point cloud,we enhance input embedding with the support of farthest point sampling and nearest neighbor search.Extensive experiments demonstrate that the PCT achieves the state-of-the-art performance on shape classification,part segmentation,semantic segmentation,and normal estimation tasks.
基金National Natural Science Foundation of China(Grant Nos.61521002 and 62132012)。
文摘Humans can naturally and effectively find salient regions in complex scenes.Motivated by this observation,attention mechanisms were introduced into computer vision with the aim of imitating this aspect of the human visual system.Such an attention mechanism can be regarded as a dynamic weight adjustment process based on features of the input image.Attention mechanisms have achieved great success in many visual tasks,including image classification,object detection,semantic segmentation,video understanding,image generation,3D vision,multimodal tasks,and self-supervised learning.In this survey,we provide a comprehensive review of various attention mechanisms in computer vision and categorize them according to approach,such as channel attention,spatial attention,temporal attention,and branch attention;a related repository https://github.com/MenghaoG uo/Awesome-Vision-Attentions is dedicated to collecting related work.We also suggest future directions for attention mechanism research.
基金Project supported by the Chinese Academy of Engi- neering, the National Natural Science Foundation of China （No. L1522023）, the National Basic Research Program （973） of China （No. 2015CB351703）, and the National Key Research and Development Plan （Nos. 2016YFB1001004 and 2016YFB1000903）
文摘The long-term goal of artificial intelligence （AI） is to make machines learn and think like human beings. Due to the high levels of uncertainty and vulnerability in human life and the open-ended nature of problems that humans are facing, no matter how intelligent machines are, they are unable to completely replace humans. Therefore, it is necessary to introduce human cognitive capabilities or human-like cognitive models into AI systems to develop a new form of AI, that is, hybrid-augmented intelligence. This form of AI or machine intelligence is a feasible and important developing model. Hybrid-augmented intelligence can be divided into two basic models： one is human-in-the-loop augmented intelligence with human-computer collaboration, and the other is cognitive computing based augmented intelligence, in which a cognitive model is embedded in the machine learning system. This survey describes a basic framework for human-computer collaborative hybrid-augmented intelligence, and the basic elements of hybrid-augmented intelligence based on cognitive computing. These elements include intuitive reasoning, causal models, evolution of memory and knowledge, especially the role and basic principles of intuitive reasoning for complex problem solving, and the cognitive learning framework for visual scene understanding based on memory and reasoning. Several typical applications of hybrid-augmented intelligence in related fields are given.
基金supported by grants from National Institutes of Health (HL093429 and HL107526 to S.-Y.C.)
文摘Vascular smooth muscle cell （VSMC） differentiation and proliferation are two important physiological proc- esses during vascular development. The phenotypic alteration from differentiated to proliferative VSMC contrib- utes to the development of several major cardiovascular diseases including atherosclerosis, hypertension, resteno- sis after angioplasty or bypass, diabetic vascular complications, and transplantation arteriopathy. Since the VSMC phenotype in these pathological conditions resembles that of developing VSMC during embryonic development, understanding of the molecular mechanisms that control VSMC differentiation will provide fundamental insights into the pathological processes of these cardiovascular diseases. Although VSMC differentiation is usually ac- companied by an irreversible cell cycle exit, VSMC proliferation and differentiation occur concurrently during embryonic development. The molecular mechanisms simultaneously regulating these two processes, however, remain largely unknown. Our recent study demonstrates that cell division cycle 7, a key regulator of cell cycle, promotes both VSMC differentiation and proliferation through different mechanisms during the initial phase of VSMC differentiation. Conversely, Kriappel-like factor 4 appears to be a repressor for both VSMC differentia- tion and proliferation. This review attempts to highlight the novel role of cell division cycle 7 in TGF-β-induced VSMC differentiation and proliferation. The role of K141ppel-like factor 4 in suppressing these two processes will also be discussed.
基金the National Natural Science Foundation of China (Grant No. 10872164)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (Grant No. 220542)+1 种基金the Key Project of Shanxi Education Committee (Grant No.05JK271)the Scientific Research Foundation of Xi’an University of Technology (Grant No.210532).
文摘Convection in a horizontal fluid layer heated from below is one of models for studying patterns of convection in binary fluid mixtures and has been extensively studied. In this article, the convection structures in a rectangular cell were investigated for the aspect-ratio Г= 12 and the separation ratio ψ = -0.47. Simulations were preformed by solving the hydrodynamic equations using the SIMPLE method. A Counter Propagating Wave （CPW） state was found in binary fluid convection with a periodically horizontal motion of defects, and the pattern dynamics was further discuss.
文摘The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) is a special reflecting Schmidt telescope. LAMOST’s special design allows both a large aperture (effective aperture of 3.6 m–4.9 m) and a wide field of view (FOV) (5°). It has an innovative active reflecting Schmidt configuration which continuously changes the mirror’s surface that adjusts during the observation process and combines thin deformable mirror active optics with segmented active optics. Its primary mirror (6.67m×6.05 m) and active Schmidt mirror (5.74m×4.40 m) are both segmented, and composed of 37 and 24 hexagonal sub-mirrors respectively. By using a parallel controllable fiber positioning technique, the focal surface of 1.75 m in diameter can accommodate 4000 optical fibers. Also, LAMOST has 16 spectrographs with 32 CCD cameras. LAMOST will be the telescope with the highest rate of spectral acquisition. As a national large scientific project, the LAMOST project was formally proposed in 1996, and approved by the Chinese government in 1997. The construction started in 2001, was completed in 2008 and passed the official acceptance in June 2009. The LAMOST pilot survey was started in October 2011 and the spectroscopic survey will launch in September 2012. Up to now, LAMOST has released more than 480 000 spectra of objects. LAMOST will make an important contribution to the study of the large-scale structure of the Universe, structure and evolution of the Galaxy, and cross-identification of multiwaveband properties in celestial objects.
基金funded by the National Basic Research Program of China (973 Program, 2014CB845700)the National Natural Science Foundation of China (Grant Nos. 11390371)Funding for the project has been provided by the National Development and Reform Commission
文摘The Large sky Area Multi-Object Fiber Spectroscopic Telescope（LAMOST） general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs. Objects in both the pilot survey and the first year regular survey are included in the LAMOST DR1. The pilot survey started in October 2011 and ended in June 2012, and the data have been released to the public as the LAMOST Pilot Data Release in August 2012. The regular survey started in September 2012, and completed its first year of operation in June 2013. The LAMOST DR1 includes a total of 1202 plates containing 2 955 336 spectra, of which 1 790 879 spectra have observed signalto-noise ratio（SNR） ≥ 10. All data with SNR ≥ 2 are formally released as LAMOST DR1 under the LAMOST data policy. This data release contains a total of 2 204 696 spectra, of which 1 944 329 are stellar spectra, 12 082 are galaxy spectra and 5017 are quasars. The DR1 not only includes spectra, but also three stellar catalogs with measured parameters： late A,FGK-type stars with high quality spectra（1 061 918 entries）, A-type stars（100 073 entries）, and M-type stars（121 522 entries）. This paper introduces the survey design, the observational and instrumental limitations, data reduction and analysis, and some caveats. A description of the FITS structure of spectral files and parameter catalogs is also provided.
基金This work is supported by National Natural Science Foundation of China(81371290),Beijing High-level Personnel Funds(2013-2-019)This study is also funded by the National Science and Technology Support Program of‘The 12th Five-Year Plan’of the Ministry of Science and Technology(2011BAI08B02).
文摘background and purpose A multicentre prospective registry study of individually tailored stenting for a patient with symptomatic intracranial atherosclerotic stenosis(ICAS)combined with poor collaterals in China showed that the short-term safety and efficacy of stenting was acceptable.However,it remained uncertain whether the low event rate could be of a long term.We reported the 1-year outcome of this registry study to evaluate the long-term efficacy of individually tailored stenting for patients with severe symptomatic ICAS combined with poor collaterals.Methods Patients with symptomatic ICAS caused by 70%-99% stenosis located at the intracranial internal carotid,middle cerebral,intracranial vertebral or basilar arteries combined with poor collaterals were enrolled.Balloon-mounted stent or balloon plus self-expanding stent were selected based on the ease of vascular access and lesion morphology determined by the operators.The primary outcome was the rate of 30-day stroke,transient ischaemic attack and death,and 12-month ischaemic stroke within the same vascular territory,haemorrhagic stroke and vascular death after stenting.results From September 2013 to January 2015,300 patients(ages 58.3±9.78 years)were recruited.Among them,159 patients were treated with balloon-mounted stent and 141 with balloon plus self-expanding stent.During the 1-year follow-up,25 patients had a primary end point event.The probability of primary outcome at 1 year was 8.1%(95% CI 5.3% to 11.7%).In 76 patients with digital subtraction angiography follow-up,27.6%(21/76)had re-stenosis≥50% and 18.4%(14/76)had re-stenosis≥70%.No baseline characteristic was associated with the primary outcome.Conclusion The event rate remains low over 1 year of individually tailored stenting for patients with severe symptomatic ICAS combined with poor collaterals.Further randomised trial of comparing individually tailored stenting with best medical therapy is needed.
基金国家自然科学基金面上项目“基于身心健康效益的智能化养老设施植物空间设计基础性研究”(编号E51678327)国家自然科学基金面上项目“基于高压人群身心健康的工作环境绿色空间体系研究”(编号E51978364)Tsinghua—ToyotaJoint Research Institute Cross-discipline Program共同资助。
