Annual mean discharge data of the five large rivers in the exorheic region of the Qing- hai-Tibet Plateau from 1956 to 2000 are analyzed for trends with the Mann-Kendall nonparametric trend test. The results reveal th...Annual mean discharge data of the five large rivers in the exorheic region of the Qing- hai-Tibet Plateau from 1956 to 2000 are analyzed for trends with the Mann-Kendall nonparametric trend test. The results reveal that though in general no in- creasing trends exist in the total river discharges, significant regional differences of river discharge ex- ist, reflecting the decreasing trends of discharge in the Yellow River and the Tongtian River (upper Changjiang River), an increasing trend in Yalong River, and inverted change in the Lancang River and Yarlung Zangbo River. Based on analyses of the seasonal discharge, it is found that climatic change had a significant effect on the seasonal variation of river discharge in the Qinghai-Tibet Plateau. In spring (from March to May) the discharge increased signifi- cantly, especially in the source area of the Yellow River. Together with the analyses on data of the mean temperature in the Northern Hemisphere and climatic data within the river basins, the relationship between discharges and mean temperature of the Northern Hemisphere is explored, which indicates that there is no increase in the stream discharge in the Qinghai-Tibet Plateau with global warming. It is probably the increasing evaporation, caused by rising temperature that offsets the hydrological effect of increasing precipitation.展开更多
Water is a critical natural resource upon which all social and economic activities and ecosystem functions depend. With a surprising social and economic development in the past decades, water has become an important c...Water is a critical natural resource upon which all social and economic activities and ecosystem functions depend. With a surprising social and economic development in the past decades, water has become an important constraint for China's sustainable development, and a matter concerning economic security, ecological security and national security of the country. Understanding the changes of water resources is greatly helpful in analyzing the impacts of climatic change, formulating plans for utilization and protection of water resources, and making water resource decisions. Based on China's national water resources assessment, the Mann-Kendall's test, and Morlet wavelet, we analyzed the changing trends and periods of China's renewable water resources during 1956–2010. The results as following:(1) There is no significant change trend of water resources on the countrywide scale during the period 1956–2010, the total water resources show a slight increasing trend, and the national annual average water resources during the period 1991–2010 increased by 1% relative to that of the period 1961–1990.(2) The changes of water resources in different level-I water resource regions vary significantly. Annual average water resources of the Haihe River and Yellow River regions in the northern China decreased 19% and 17% respectively in the past 20 years. Water resource increased in Southern and Northwestern rivers regions, particularly in the Northwest rivers region, with the increasing amplitude by nearly 10% in the past 20 years.(3) The inter-annual variation of national water resource became larger in the past 20 years, as compared with that of the period 1961–1990. The coefficients of water resource variation increased in Northwestern and Southwestern rivers regions, while the inter-annual variation tended to decrease in the Haihe and the Yellow River regions where significant decline of water resources happened.(4) A 14-year quasi-periodicity of the national water resource variation was detected, overlapping with various periodicities of water resources of different level-I water resource regions. Remarkable uniformity exists between the first or secondary primary periodicity of water resource variation in adjacent level-I water resource regions.展开更多
CANDECOMP/PARAFAC(CP) tensor factorization is an efficient technique for incomplete tensor-data processing through capturing the multilinear latent factors. Based on the incorporate a sparsity-inducing prior over mult...CANDECOMP/PARAFAC(CP) tensor factorization is an efficient technique for incomplete tensor-data processing through capturing the multilinear latent factors. Based on the incorporate a sparsity-inducing prior over multiple latent factors and appropriate hyper-priors over all hyper-parameters, a Bayesian-based hierarchical probabilistic CP factorization model could be formed. By this way, the rank of the incomplete tensor can be determined automatically. In this paper, we explored the tensor completion method in processing incomplete multidimensional electroencephalogram(EEG) and magnetic resonance imaging(MRI) clinical data. The empirical results indicated that the Bayesian CP tensor factorization of incomplete data method can effectively recover EEG signal with missing data and denoised the noisy MRI data.展开更多
Mean-variance relationship （MVR）, nowadays agreed in power law form, is an important function. It is currently used by traffic matrix estimation as a basic statistical assumption. Because all the existing papers obt...Mean-variance relationship （MVR）, nowadays agreed in power law form, is an important function. It is currently used by traffic matrix estimation as a basic statistical assumption. Because all the existing papers obtain MVR only through empirical ways, they cannot provide theoretical support to power law MVR or the definition of its power exponent. Furthermore, because of the lack of theoretical model, all traffic matrix estimation methods based on MVR have not been theoretically supported yet. By observing both our laboratory and campus network for more than one year, we find that such an empirical MVR is not sufficient to describe actual network traffic. In this paper, we derive a theoretical MVR from ON/OFF model. Then we prove that current empirical power law MVR is generally reasonable by the fact that it is an approximate form of theoretical MVR under specific precondition, which can theoretically support those traffic matrix estimation algorithms of using MVR. Through verifying our MVR by actual observation and public DECPKT traces, we verify that our theoretical MVR is valid and more capable of describing actual network traffic than power law MVR.展开更多
The recently introduced multivariate multiscale sample entropy(MMSE)well evaluates the long correlations in multiple channels,so that it can reveal the complexity of multivariate biological signals.The existing MMSE a...The recently introduced multivariate multiscale sample entropy(MMSE)well evaluates the long correlations in multiple channels,so that it can reveal the complexity of multivariate biological signals.The existing MMSE algorithm deals with short time series statically whereas long time series are common for real-time computation in practical use.As a solution,we novelly proposed our dynamic MMSE(DMMSE)as an extension of MMSE.This helps us gain greater insight into the complexity of each section of time series,producing multifaceted and more robust estimates than the standard MMSE.The simulation results illustrated the feasibility and well performance in the brain death diagnosis.展开更多
In this study,two casting speeds of 10 and 30 r/min were used in vertical twin-roll casting(TRC)to obtain Mg-rare earth(Mg-RE)alloys,and their microstructures,corrosion behaviours and in vivo bone reactions were inves...In this study,two casting speeds of 10 and 30 r/min were used in vertical twin-roll casting(TRC)to obtain Mg-rare earth(Mg-RE)alloys,and their microstructures,corrosion behaviours and in vivo bone reactions were investigated in detail.The results indicated that the roll-castings of TRC-30 r/min exhibited a finer grain size and higher volume fraction of non-crystallization than those in castings of TRC-10 r/min.Moreover,the results of electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization indicated that the castings of TRC-30 r/min displayed a higher corrosion resistance compared with those in the castings of TRC-10 r/min.Animal tests showed that a higher degree of newly formed bone tissues was achieved by implants of TRC-30 r/min.Additionally,in vivo tests displayed that degradation properties of the TRC-30-r/min implants were better than those of the TRC-10-r/min implants;furthermore,the degradation layer was a two-layer structure,and P and Ca were enriched in the outer degradation layer.In summary,these findings elucidated that casting speed has a substantial effect on the microstructure and degradation property of Mg-based implants,and the degradation property performs better with increased casting speed.展开更多
文摘Annual mean discharge data of the five large rivers in the exorheic region of the Qing- hai-Tibet Plateau from 1956 to 2000 are analyzed for trends with the Mann-Kendall nonparametric trend test. The results reveal that though in general no in- creasing trends exist in the total river discharges, significant regional differences of river discharge ex- ist, reflecting the decreasing trends of discharge in the Yellow River and the Tongtian River (upper Changjiang River), an increasing trend in Yalong River, and inverted change in the Lancang River and Yarlung Zangbo River. Based on analyses of the seasonal discharge, it is found that climatic change had a significant effect on the seasonal variation of river discharge in the Qinghai-Tibet Plateau. In spring (from March to May) the discharge increased signifi- cantly, especially in the source area of the Yellow River. Together with the analyses on data of the mean temperature in the Northern Hemisphere and climatic data within the river basins, the relationship between discharges and mean temperature of the Northern Hemisphere is explored, which indicates that there is no increase in the stream discharge in the Qinghai-Tibet Plateau with global warming. It is probably the increasing evaporation, caused by rising temperature that offsets the hydrological effect of increasing precipitation.
基金funded by the National Basic Research Program of China (Grant No. 2010CB428406)the External Cooperation Program of the Chinese Academy of Sciences (Grant No. GJHZ1016)
文摘Water is a critical natural resource upon which all social and economic activities and ecosystem functions depend. With a surprising social and economic development in the past decades, water has become an important constraint for China's sustainable development, and a matter concerning economic security, ecological security and national security of the country. Understanding the changes of water resources is greatly helpful in analyzing the impacts of climatic change, formulating plans for utilization and protection of water resources, and making water resource decisions. Based on China's national water resources assessment, the Mann-Kendall's test, and Morlet wavelet, we analyzed the changing trends and periods of China's renewable water resources during 1956–2010. The results as following:(1) There is no significant change trend of water resources on the countrywide scale during the period 1956–2010, the total water resources show a slight increasing trend, and the national annual average water resources during the period 1991–2010 increased by 1% relative to that of the period 1961–1990.(2) The changes of water resources in different level-I water resource regions vary significantly. Annual average water resources of the Haihe River and Yellow River regions in the northern China decreased 19% and 17% respectively in the past 20 years. Water resource increased in Southern and Northwestern rivers regions, particularly in the Northwest rivers region, with the increasing amplitude by nearly 10% in the past 20 years.(3) The inter-annual variation of national water resource became larger in the past 20 years, as compared with that of the period 1961–1990. The coefficients of water resource variation increased in Northwestern and Southwestern rivers regions, while the inter-annual variation tended to decrease in the Haihe and the Yellow River regions where significant decline of water resources happened.(4) A 14-year quasi-periodicity of the national water resource variation was detected, overlapping with various periodicities of water resources of different level-I water resource regions. Remarkable uniformity exists between the first or secondary primary periodicity of water resource variation in adjacent level-I water resource regions.
基金supported by the JSPS KAKENHI,Japan(Grant Nos.17K00326 and 18K04178)the National Natural Science Foundation of China(Grant Nos.61773129,61633010)the JST CREST,Japan(Grant No.JPMJCR1784)。
文摘CANDECOMP/PARAFAC(CP) tensor factorization is an efficient technique for incomplete tensor-data processing through capturing the multilinear latent factors. Based on the incorporate a sparsity-inducing prior over multiple latent factors and appropriate hyper-priors over all hyper-parameters, a Bayesian-based hierarchical probabilistic CP factorization model could be formed. By this way, the rank of the incomplete tensor can be determined automatically. In this paper, we explored the tensor completion method in processing incomplete multidimensional electroencephalogram(EEG) and magnetic resonance imaging(MRI) clinical data. The empirical results indicated that the Bayesian CP tensor factorization of incomplete data method can effectively recover EEG signal with missing data and denoised the noisy MRI data.
基金Supported by the National Basic Research Program of China (Grant No. G2005CB321901)
文摘Mean-variance relationship （MVR）, nowadays agreed in power law form, is an important function. It is currently used by traffic matrix estimation as a basic statistical assumption. Because all the existing papers obtain MVR only through empirical ways, they cannot provide theoretical support to power law MVR or the definition of its power exponent. Furthermore, because of the lack of theoretical model, all traffic matrix estimation methods based on MVR have not been theoretically supported yet. By observing both our laboratory and campus network for more than one year, we find that such an empirical MVR is not sufficient to describe actual network traffic. In this paper, we derive a theoretical MVR from ON/OFF model. Then we prove that current empirical power law MVR is generally reasonable by the fact that it is an approximate form of theoretical MVR under specific precondition, which can theoretically support those traffic matrix estimation algorithms of using MVR. Through verifying our MVR by actual observation and public DECPKT traces, we verify that our theoretical MVR is valid and more capable of describing actual network traffic than power law MVR.
基金supported by KAKENHI(Grant Nos.21360179,22560425)(JAPAN)supported by the Key Project of National Science Foundation of China(Grant Nos.11232005)The Ministry of Education Doctoral Foundation(Grant Nos.20120074110020)
文摘The recently introduced multivariate multiscale sample entropy(MMSE)well evaluates the long correlations in multiple channels,so that it can reveal the complexity of multivariate biological signals.The existing MMSE algorithm deals with short time series statically whereas long time series are common for real-time computation in practical use.As a solution,we novelly proposed our dynamic MMSE(DMMSE)as an extension of MMSE.This helps us gain greater insight into the complexity of each section of time series,producing multifaceted and more robust estimates than the standard MMSE.The simulation results illustrated the feasibility and well performance in the brain death diagnosis.
基金supported by the Hi-Tech Research Center and Animal Experiment Project(Grant No.2019-5)at Saitama Institute of Technology.
文摘In this study,two casting speeds of 10 and 30 r/min were used in vertical twin-roll casting(TRC)to obtain Mg-rare earth(Mg-RE)alloys,and their microstructures,corrosion behaviours and in vivo bone reactions were investigated in detail.The results indicated that the roll-castings of TRC-30 r/min exhibited a finer grain size and higher volume fraction of non-crystallization than those in castings of TRC-10 r/min.Moreover,the results of electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization indicated that the castings of TRC-30 r/min displayed a higher corrosion resistance compared with those in the castings of TRC-10 r/min.Animal tests showed that a higher degree of newly formed bone tissues was achieved by implants of TRC-30 r/min.Additionally,in vivo tests displayed that degradation properties of the TRC-30-r/min implants were better than those of the TRC-10-r/min implants;furthermore,the degradation layer was a two-layer structure,and P and Ca were enriched in the outer degradation layer.In summary,these findings elucidated that casting speed has a substantial effect on the microstructure and degradation property of Mg-based implants,and the degradation property performs better with increased casting speed.
