6 resultados para digital knowledge maps

em Chinese Academy of Sciences Institutional Repositories Grid Portal


Relevância:

80.00% 80.00%

Publicador:

Resumo:

对古龙咀周围浅海区沉积物的粒度进行了测试与分析,结合相关的地质水文资料,探讨了海岸形态对沉积物粒度的影响。研究区表层沉积物平均粒径在海湾浅海区呈带状由岸向海变细,中等水深和岬角处分布着细粒区,向外海粒径相对变粗;除险岛湾砂质区外,分选差;偏态多数为正偏或近正态;整体峰形极窄,峰型多样。底质类型以粘土质粉砂和砂质粉砂为主,由东北经古龙咀岬角向西南形成S形粘土质粉砂分布带,险岛湾地区沉积物呈带状由砂逐渐过渡到粉砂。潮汐和波浪是本区沉积物输运的主要水动力,岬角的存在影响了沉积物粒度的分布。粒度趋势分析表明沉积物整体有向岬角汇聚的输运趋势。 对收集到基于1954年、1969年、1982年测量绘成的地形图水深数据进行数字化,结合2005年测量的水深数据,分别建立各时期DEM图,在此基础上分析研究区的地形特征。四个时期海底DEM呈现出大体一致的趋势,在险岛湾及白沙口海湾内为浅水区,水深值在-1~-4 m之间,深水区主要分布在南黄岛南端至古龙咀连线以南区域,呈扇形展布,水深由南黄岛两侧向中间逐渐加深,水深值在-10~ -17 m之间。从整体上看,研究区海底地形呈NW-SE方向逐渐加深。 将数字化后的水深数据统一校正到1956黄海高程系,分别建立DEM,运用GIS的栅格计算分析得出冲淤变化图。相关结果表明:1954~1969年研究区整体近岸为冲(险岛湾除外),离岸海域为淤;1969~1982年研究区总体处于弱淤积状态;1982-2005研究区海域近岸为淤,外海以弱冲刷状态为主。

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Exploit Tarim Basin Historical Physical Geographic Information System by linking historical documents and Geographic Information System, reconstruct the physical environmental evolution in Tarirn Basin during historical period (the last 2 Ka), special discuss riverhead of the Yellow River and Lop Nur. Based on analyzing Chinese historical documents (antiquity maps and texts), extract physical environmental information in Xiyu during historical period from Twenty-Five History and geographic books and records past dynasties, divide it into 4 period of time. Regarding digital topographical maps as base maps and looking on water bodies, vegetation and desert as central factors, quantify historical physical geographic data in Geographic Information System in terms of dynastic combination of Xianqin-Han, Jin-Wei-Nanbeichao, Tang-Wudai and Song-Yuan-Ming-Qing, execute physical environmental maps of Xiyu through the ages, in order to image the changes of water system, oasis and desert in Xiyu during the last 2 Ka. Compare cross orientation the relation of environmental factors all historical period of time from the influence of climate to oasis and desert, deem that climate condition decided ecological structure in direct and restrict the extent of desertification, especially climate corresponded the style of oasis and the spread of desert in the period of Jin-Wei-Nanbeichao and Tang-Wudai. Compare portrait direction the physical environmental characters in Xiyu during different period of time from 5 aspects of water bodies, oasis, desert, products and climate, deem that physical environment in Xiyu changed in all aspects during historical period. The origin of Lysenkoism about the Yellow River Undercurrent is agelong, whose ascending and descending at times due to investigating the riverhead of the Yellow River time after time during historical period and researching and disputing about the geographic location of Jishishan Mountain. It could consider the faultage in northeastern Qinghai-Xizang Plateau as the channels of undercurrent according to the research of modern geoscience field in the riverhead region.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Knowledge management is a critical issue for the next-generation web application, because the next-generation web is becoming a semantic web, a knowledge-intensive network. XML Topic Map (XTM), a new standard, is appearing in this field as one of the structures for the semantic web. It organizes information in a way that can be optimized for navigation. In this paper, a new set of hyper-graph operations on XTM (HyO-XTM) is proposed to manage the distributed knowledge resources.HyO-XTM is based on the XTM hyper-graph model. It is well applied upon XTM to simplify the workload of knowledge management.The application of the XTM hyper-graph operations is demonstrated by the knowledge management system of a consulting firm. HyO-XTM shows the potential to lead the knowledge management to the next-generation web.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Concept maps are an important tool to knowledge organization,representation, and sharing. Most current concept map tools do not provide full support for hand-drawn concept map creation and manipulation, largely due to the lack of methods to recognize hand-drawn concept maps. This paper proposes a structure recognition method. Our algorithm can extract node blocks and link blocks of a hand-drawn concept map by combining dynamic programming and graph partitioning and then build a concept-map structure by relating extracted nodes and links. We also introduce structure-based intelligent manipulation technique of hand-drawn concept maps. Evaluation shows that our method has high structure recognition accuracy in real time, and the intelligent manipulation technique is efficient and effective.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

National Natural Science Foundation of China [40871177]; Project of State Key Lab of Resources and Environmental Information System [088RA304SA]; CAS Knowledge Innovation Project

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Qinghai-Tibet Plateau lies in the place of the continent-continent collision between Indian and Eurasian plates. Because of their interaction the shallow and deep structures are very complicated. The force system forming the tectonic patterns and driving tectonic movements is effected together by the deep part of the lithosphere and the asthenosphere. It is important to study the 3-D velocity structures, the spheres and layers structures, material properties and states of the lithosphere and the asthenosphere for getting knowledge of their formation and evolution, dynamic process, layers coupling and exchange of material and energy. Based on the Rayleigh wave dispersion theory, we study the 3-D velocity structures, the depths of interfaces and thicknesses of different layers, including the crust, the lithosphere and the asthenosphere, the lithosphere-asthenosphere system in the Qinghai-Tibet Plateau and its adjacent areas. The following tasks include: (1)The digital seismic records of 221 seismic events have been collected, whose magnitudes are larger than 5.0 over the Qinghai-Tibet Plateau and its adjacent areas. These records come from 31 digital seismic stations of GSN , CDSN、NCDSN and part of Indian stations. After making instrument response calibration and filtering, group velocities of fundamental mode of Rayleigh waves are measured using the frequency-time analysis (FTAN) to get the observed dispersions. Furthermore, we strike cluster average for those similar ray paths. Finally, 819 dispersion curves (8-150s) are ready for dispersion inversion. (2)From these dispersion curves, pure dispersion data in 2°×2° cells of the areas (18°N-42°N, 70°E-106°E) are calculated by using function expansion method, proposed by Yanovskaya. The average initial model has been constructed by taking account of global AK135 model along with geodetic, geological, geophysical, receiving function and wide-angle reflection data. Then, initial S-wave velocity structures of the crust and upper mantle in the research areas have been obtained by using linear inversion (SVD) method. (3)Taking the results of the linear inversion as the initial model, we simultaneously invert the S wave velocities and thicknesses by using non-linear inversion (improved Simulated Annealing algorithm). Moreover, during the temperature dropping the variable-scale models are used. Comparing with the linear results, the spheres and layers by the non-linear inversion can be recognized better from the velocity value and offset. (4)The Moho discontinuity and top interface of the asthenosphere are recognized from the velocity value and offset of the layers. The thicknesses of the crust, lithosphere and asthenosphere are gained. These thicknesses are helpful to studying the structural differentia between the Qinghai-Tibet Plateau and its adjacent areas and among geologic units of the plateau. The results of the inversion will provide deep geophysical evidences for studying deep dynamical mechanism and exploring metal mineral resource and oil and gas resources. The following conclusions are reached by the distributions of the S wave velocities and thicknesses of the crust, lithosphere and asthenosphere, combining with previous researches. (1)The crust is very thick in the Qinghai-Tibet Plateau, varying from 60 km to 80 km. The lithospheric thickness in the Qinghai-Tibet Plateau is thinner (130-160 km) than its adjacent areas. Its asthenosphere is relatively thicker, varies from 150 km to 230 km, and the thickest area lies in the western Qiangtang. India located in south of Main Boundary thrust has a thinner crust (32-38 km), a thicker lithosphere of about 190 km and a rather thin asthenosphere of only 60 km. Sichuan and Tarim basins have the crust thickness less than 50km. Their lithospheres are thicker than the Qinghai-Tibet Plateau, and their asthenospheres are thinner. (2)The S-wave velocity variation pattern in the lithosphere-asthenosphere system has band-belted distribution along east-westward. These variations correlate with geology structures sketched by sutures and major faults. These sutures include Main Boundary thrust (MBT), Yarlung-Zangbo River suture (YZS), Bangong Lake-Nujiang suture (BNS), Jinshajiang suture (JSJS), Kunlun edge suture (KL). In the velocity maps of the upper and middle crust, these sutures can be sketched. In velocity maps of 250-300 km depth, MBT, BNS and JSJS can be sketched. In maps of the crustal thickness, the lithospheric thickness and the asthenospheric thickness, these sutures can be still sketched. In particular, MBT can be obviously resolved in these velocity maps and thickness maps. (3)Since the collision between India and Eurasian plate, the “loss” of surface material arising from crustal shortening is caused not only by crustal thickening but also by lateral extrusion material. The source of lateral extrusion lies in the Qiangtang block. These materials extrude along the JSJS and BNS with both rotation and dispersion in Daguaiwan. Finally, it extends toward southeast direction. (4)There is the crust-mantle transition zone of no distinct velocity jump in the lithosphere beneath the Qiangtang Terrane. It has thinner lithosphere and developed thicker asthenosphere. It implies that the crust-mantle transition zone of partial melting is connected with the developed asthenosphere. The underplating of asthenosphere may thin the lithosphere. This buoyancy might be the main mechanism and deep dynamics of the uplift of the Qinghai-Tibet hinterland. At the same time, the transport of hot material with low velocity intrudes into the upper mantle and the lower crust along cracks and faults forming the crust-mantle transition zone.