This study investigates the statistical linkage between summer rainfall in China and the preceding spring Eurasian snow water equivalent (SWE), using the datasets of summer rainfall observations from 513 stations, satellite-observed snow water equivalent, and atmospheric circulation variables in the NCEP/NCAR reanalysis during the period from 1979 to 2004. The first two coupled modes are identified by using the singular value decomposition (SVD) method. The leading SVD mode of the spring SWE variability shows a coherent negative anomaly in most of Eurasia with the opposite anomaly in some small areas of the Tibetan Plateau and East Asia. The mode displays strong interannual variability, superposed on an interdecadal variation that occurred in the late 1980s, with persistent negative phases in 1979–1987 and frequent positive phases afterwards. When the leading mode is in its positive phase, it corresponds to less SWE in spring throughout most of Eurasia. Meanwhile, excessive SWE in some small areas of the Tibetan Plateau and East Asia, summer rainfall in South and Southeast China tends to be increased, whereas it would be decreased in the up-reaches of the Yellow River. In recent two decades, the decreased spring SWE in Eurasia may be one of reasons for severe droughts in North and Northeast China and much more significant rainfall events in South and Southeast China. The second SVD mode of the spring SWE variability shows opposite spatial variations in western and eastern Eurasia, while most of the Tibetan Plateau and East Asia are in phase. This mode significantly correlates with the succeeding summer rainfall in North and Northeast China, that is, less spring SWE in western Eurasia and excessive SWE in eastern Eurasia and the Tibetan Plateau tend to be associated with decreased summer rainfall in North and Northeast China.
In order to solve the problem of mining biomedical knowledge, a biomedical semantic-based knowledge discovery method (Bio-SKDM) is proposed. Using the semantic types and semantic relations of the biomedical concepts, Bio-SKDM can identify the relevant concepts collected from Medline and generate the novel hypothesis between these concepts. The experiment result shows that compared with ARROWSMITH and LITLINKER, Bio-SKDM generates less but more relevant novel hypotheses and requires less human intervention in the discovery procedure.
LI GuangrongHUANG ChuanheZHANG XiaodanXU XuhengHU Xiaohua
A novel centralized approach for Dynamic Spectrum Allocation (DSA) in the Cognitive Radio (CR) network is presented in this paper. Instead of giving the solution in terms of formulas modeling network environment such as linear programming or convex optimization, the new approach obtains the capability of iteratively on-line learning environment performance by using Reinforcement Learning (RL) algorithm after observing the variability and uncertainty of the heterogeneous wireless networks. Appropriate decision-making access actions can then be obtained by employing Fuzzy Inference System (FIS) which ensures the strategy being able to explore the possible status and exploit the experiences sufficiently. The new approach considers multi-objective such as spectrum efficiency and fairness between CR Access Points (AP) effectively. By interacting with the environment and accumulating comprehensive advantages, it can achieve the largest long-term reward expected on the desired objectives and implement the best action. Moreover, the present algorithm is relatively simple and does not require complex calculations. Simulation results show that the proposed approach can get better performance with respect to fixed frequency planning scheme or general dynamic spectrum allocation policy.
Based on the field data obtained during cruises on the shelf of the East China Sea from 1997 to 1999, seasonal variations of coastal upwelling on the inner shelf are discussed by using cross-shelf transect profiles and horizontal distributions of chemical and hydrographic variables. Results show that the coastal upwelling was year-round, but the areas and intensities of the upwelling were quite different in season. The coastal upwelling occurred in all of the coastal areas of the region in spring and summer, but in autumn only in the area off Zhejiang Province, and in winter in the area off Fujian Prov- ince. It was the strongest in summer and the weakest in winter. Geographically, it was the strongest in the area off Zhejiang Province and the weakest in the southmost or northmost parts of the East China Sea. The estimated nutrient fluxes upward into euphotic zone through coastal upwelling were quite large, es- pecially for phosphate, which contributed significantly to primary production and improved the nutrient structure of the coastal ecosystem in the East China Sea.
It was observed that hydrazine could enhance the chemiluminescence （CL） intensity of tris-（1,10-phenanthroline）ruthenium（Ⅱ）（Ru（phen）3 2+ ）- Cerium（Ⅳ） （Ce（Ⅳ）） system, based on which, a novel CL system, Ru（phen）3 2+ -Hydrazine-Ce（Ⅳ）, was established. This CL system was investigated and employed to detect hydrazine. Under the optimum experimental conditions, the linear range and detection limit of the proposed method are 2.0×10 -6 -2.0×10 -3 g·L -1 and 1.8×10 -6 g·L -1 , respectively. For 1.5×10 -5 , 1.5×10 -4 and 1.2×10 -3 g·L -1 hydrazine, the relative standard deviation （RSD） is 2.9%, 2.2% and 3.1%, respectively （n=11）. The proposed method has been used to detect the content of hydrazine in the synthetic samples with satisfactory results.
SHI Bo＇anZENG DanyunJI XinghuXI JuanAI XinpingHE Zhike
