Spatio-temporal variability and dynamics in Sahelian agro-pastoral zones make each local situation a special case. These specificities must be considered to guide the dissemination of agricultural options with a view ...Spatio-temporal variability and dynamics in Sahelian agro-pastoral zones make each local situation a special case. These specificities must be considered to guide the dissemination of agricultural options with a view to sustainable development. The territorial scale of municipalities is not sufficient for this necessary contextualization;the scale of the “village terroir” seems to be a better option. This is the hypothesis we put forward in the framework of the Global Collaboration for Resilient Food Systems program (CRFS), i.e. local context is spatially defined by village terroir. The study is based on data collected through participatory mapping and surveys in “village terroirs” in three regions of Niger (Maradi, Dosso and Tillabéri). Then the links between farm managers and their cultivated land, as well as the spatio-temporal dynamics of local context are analyzed. This study provides evidence of the existence and functional usefulness of the village terroir for farmers, their land management and their activities. It demonstrates the usefulness of contextualizing agricultural options at this scale. Their analysis elucidates the links between “terroirs village” and the specific functioning of the agrosocio-ecosystems acting on each of them, thus laying the systemic and geographical foundations for a model of the spatio- temporal dynamics of “village terroirs”. This initial work has opened up new perspectives in modeling and sustainable development.展开更多
Alzheimer＇s disease （AD）, the predominant form of dementia, is a chronic, incurable neurodegenerative disorder presenting with symptoms includ- ing progressive memory loss and disturbed emotional state. It has been...Alzheimer＇s disease （AD）, the predominant form of dementia, is a chronic, incurable neurodegenerative disorder presenting with symptoms includ- ing progressive memory loss and disturbed emotional state. It has been estimated that dementia affects over 47 million people worldwide （Prince et al., 2015）, and with 60-80% of cases attributable to AD.展开更多
Based on the complex variable moving least-square（CVMLS） approximation and a local symmetric weak form,the complex variable meshless local Petrov-Galerkin（CVMLPG） method of solving two-dimensional potential proble...Based on the complex variable moving least-square（CVMLS） approximation and a local symmetric weak form,the complex variable meshless local Petrov-Galerkin（CVMLPG） method of solving two-dimensional potential problems is presented in this paper.In the present formulation,the trial function of a two-dimensional problem is formed with a one-dimensional basis function.The number of unknown coefficients in the trial function of the CVMLS approximation is less than that in the trial function of the moving least-square（MLS） approximation.The essential boundary conditions are imposed by the penalty method.The main advantage of this approach over the conventional meshless local Petrov-Galerkin（MLPG） method is its computational efficiency.Several numerical examples are presented to illustrate the implementation and performance of the present CVMLPG method.展开更多
By simulating the electron paramagnetic resonance （EPR） and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl...By simulating the electron paramagnetic resonance （EPR） and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl：V2＋ （M=Na, K, Rb） systems at 77K, 195 K and RT （room temperature 295 K or 302 K）, respectively. The theoretical results indicate that there exists a compressed distortion in MCl：V2＋ systems. Meanwhile, it finds that the structure parameters R1, R2 and ｜△R｜（ = R1 - R2） increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. △R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed.展开更多
In this paper, a new mechanism for the emergence of scale-free distribution is proposed. It is more realistic than the existing mechanism. Based on our mechanism, a model responsible for the scale-free distribution wi...In this paper, a new mechanism for the emergence of scale-free distribution is proposed. It is more realistic than the existing mechanism. Based on our mechanism, a model responsible for the scale-free distribution with an exponent in a range of 3-to-5 is given. Moreover, this model could also reproduce the exponential distribution that is discovered in some real networks. Finally, the analytical result of the model is given and the simulation shows the validity of our result,展开更多
A weighted Koppelman-Leray-Norguet formula of (r, s) differential forms on a local q-concave wedge in a complex manifold is obtained. By constructing the new weighted kernels, the authors give a new weighted Koppelman...A weighted Koppelman-Leray-Norguet formula of (r, s) differential forms on a local q-concave wedge in a complex manifold is obtained. By constructing the new weighted kernels, the authors give a new weighted Koppelman-Leray-Norguet formula without boundary integral of (r, s) differential forms, which is different from the classical one. The new weighted formula is especially suitable for the case of the local g-concave wedge with a non-smooth boundary, so one can avoid complex estimates of boundary integrals and the density of integral may be not defined on the boundary but only in the domain. Moreover, the weighted integral formulas have much freedom in applications such as in the interpolation of functions.展开更多
With the help of the symbolic computation system Maple, the Riccati equation mapping approach and a linear variable separation approach, a new family of complex solutions for the （2＋ 1）-dimensional Boiti-Leon-Pempi...With the help of the symbolic computation system Maple, the Riccati equation mapping approach and a linear variable separation approach, a new family of complex solutions for the （2＋ 1）-dimensional Boiti-Leon-Pempinelli system （BLP） is derived. Based on the derived solitary wave solution, some novel complex wave localized excitations are obtained.展开更多
累计局部离群因子(cumulative local outlier factor,C_LOF)算法能有效解决数据流中的概念漂移问题和克服离群点检测中的伪装问题,但在处理高维数据时,时间复杂度较高。为有效解决时间复杂度高的问题,提出一种基于投影索引近邻的累计局...累计局部离群因子(cumulative local outlier factor,C_LOF)算法能有效解决数据流中的概念漂移问题和克服离群点检测中的伪装问题,但在处理高维数据时,时间复杂度较高。为有效解决时间复杂度高的问题,提出一种基于投影索引近邻的累计局部离群因子(cumulative local outlier factor based projection indexed nearest neighbor,PINN_C_LOF)算法。使用滑动窗口维护活跃数据点,在新数据到达和旧数据过期时,引入投影索引近邻(projection indexed nearest neighbor,PINN)方法,增量更新窗口中受影响数据点的近邻。实验结果表明,PINN_C_LOF算法在检测高维流数据离群值时,在保持检测精确度的前提下,其时间复杂度较C_LOF算法明显降低。展开更多
为解决许多关键节点识别算法在评估网络节点重要性时,忽视节点与其邻居节点间的相互关系,导致对网络鲁棒性和脆弱性的评估结果不准确的问题,提出一种改良的局部加权密度度量方式CPR-WCCN,旨在以较低的计算成本准确识别复杂网络中的关键...为解决许多关键节点识别算法在评估网络节点重要性时,忽视节点与其邻居节点间的相互关系,导致对网络鲁棒性和脆弱性的评估结果不准确的问题,提出一种改良的局部加权密度度量方式CPR-WCCN,旨在以较低的计算成本准确识别复杂网络中的关键节点.首先,借助节点间的最短路径长度和数量,定义节点间的通信概率序列.其次,通过结合通信概率和相对熵(Communication Probability and Relative Entropy,CPR),将传统的二元邻接矩阵转化为网络归一化相关矩阵.再次,结合加权聚类系数和邻居节点的影响(Weighted Clustering Coefficients and Neighbor Influence,WCCN),得到改进的考虑邻居影响的局部加权密度.最后,为验证CPRWCCN算法的效果,在故意攻击和随机攻击下进行模拟实验,利用传播模型在4种实际网络上对CPR-WCCN与其他5种算法进行对比分析.实验结果表明:当网络遭受故意攻击,导致前15个关键节点失效时,网络的连通性、效率、最大连接子图以及自然连通性等关键指标较随机攻击出现了更显著的下降;相较于其他5种算法,CPR-WCCN算法表现出最优的整体性能,能够准确且高效地识别出网络中的关键节点.展开更多
文摘Spatio-temporal variability and dynamics in Sahelian agro-pastoral zones make each local situation a special case. These specificities must be considered to guide the dissemination of agricultural options with a view to sustainable development. The territorial scale of municipalities is not sufficient for this necessary contextualization;the scale of the “village terroir” seems to be a better option. This is the hypothesis we put forward in the framework of the Global Collaboration for Resilient Food Systems program (CRFS), i.e. local context is spatially defined by village terroir. The study is based on data collected through participatory mapping and surveys in “village terroirs” in three regions of Niger (Maradi, Dosso and Tillabéri). Then the links between farm managers and their cultivated land, as well as the spatio-temporal dynamics of local context are analyzed. This study provides evidence of the existence and functional usefulness of the village terroir for farmers, their land management and their activities. It demonstrates the usefulness of contextualizing agricultural options at this scale. Their analysis elucidates the links between “terroirs village” and the specific functioning of the agrosocio-ecosystems acting on each of them, thus laying the systemic and geographical foundations for a model of the spatio- temporal dynamics of “village terroirs”. This initial work has opened up new perspectives in modeling and sustainable development.
文摘Alzheimer＇s disease （AD）, the predominant form of dementia, is a chronic, incurable neurodegenerative disorder presenting with symptoms includ- ing progressive memory loss and disturbed emotional state. It has been estimated that dementia affects over 47 million people worldwide （Prince et al., 2015）, and with 60-80% of cases attributable to AD.
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 11102125)
文摘Based on the complex variable moving least-square（CVMLS） approximation and a local symmetric weak form,the complex variable meshless local Petrov-Galerkin（CVMLPG） method of solving two-dimensional potential problems is presented in this paper.In the present formulation,the trial function of a two-dimensional problem is formed with a one-dimensional basis function.The number of unknown coefficients in the trial function of the CVMLS approximation is less than that in the trial function of the moving least-square（MLS） approximation.The essential boundary conditions are imposed by the penalty method.The main advantage of this approach over the conventional meshless local Petrov-Galerkin（MLPG） method is its computational efficiency.Several numerical examples are presented to illustrate the implementation and performance of the present CVMLPG method.
基金Project supported by the National Natural Science Foundation of China (Grant No 10774103)the Doctoral Education Fund of the Education Ministry of China (Grant No 20050610011)
文摘By simulating the electron paramagnetic resonance （EPR） and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl：V2＋ （M=Na, K, Rb） systems at 77K, 195 K and RT （room temperature 295 K or 302 K）, respectively. The theoretical results indicate that there exists a compressed distortion in MCl：V2＋ systems. Meanwhile, it finds that the structure parameters R1, R2 and ｜△R｜（ = R1 - R2） increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. △R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 60374037 and 60574036）, the Program for New Century Excellent Talents of High Education of China（Grant No NCET 2005-290）, The Special Research Fund for the Doctoral Program of High Education of China （Grant No 20050055013）.Acknowledgments The authors would like to thank Réka Albert for useful discussion and are grateful to the anonymous referees for their valuable suggestions and comments, which have made this paper improved.
文摘In this paper, a new mechanism for the emergence of scale-free distribution is proposed. It is more realistic than the existing mechanism. Based on our mechanism, a model responsible for the scale-free distribution with an exponent in a range of 3-to-5 is given. Moreover, this model could also reproduce the exponential distribution that is discovered in some real networks. Finally, the analytical result of the model is given and the simulation shows the validity of our result,
基金National Natural Science Foundation and Mathematical "Tian Yuan" Foundation of China (10271097 and TY10126033)
文摘A weighted Koppelman-Leray-Norguet formula of (r, s) differential forms on a local q-concave wedge in a complex manifold is obtained. By constructing the new weighted kernels, the authors give a new weighted Koppelman-Leray-Norguet formula without boundary integral of (r, s) differential forms, which is different from the classical one. The new weighted formula is especially suitable for the case of the local g-concave wedge with a non-smooth boundary, so one can avoid complex estimates of boundary integrals and the density of integral may be not defined on the boundary but only in the domain. Moreover, the weighted integral formulas have much freedom in applications such as in the interpolation of functions.
基金Project supported by the National Natural Science Foundation of China(Grant No.11375079)the Natural Science Foundation of Zhejiang Province,China(Grant Nos.Y6100257 and Y6110140)
文摘With the help of the symbolic computation system Maple, the Riccati equation mapping approach and a linear variable separation approach, a new family of complex solutions for the （2＋ 1）-dimensional Boiti-Leon-Pempinelli system （BLP） is derived. Based on the derived solitary wave solution, some novel complex wave localized excitations are obtained.
文摘蛋白质复合物的检测有助于从分子水平上理解生命的活动过程。针对群智能算法检测蛋白质复合物时假阳/阴性率高、准确率低、种群多样性下降等问题,提出了基于强化学习的离散层级萤火虫算法检测蛋白质复合物(reinforcement learning-based discrete level firefly algorithm for detecting protein complexes,RLDLFA-DPC)。引入强化学习思想提出一种自适应层级划分策略,动态调整层级结构,能有效解决迭代后期种群多样性下降的问题。在层级学习策略中个体向两个优秀层级学习,避免算法陷入局部最优。为了提高蛋白质复合物检测的精度,结合个体环境信息提出自适应搜索半径的局部搜索策略。最后,在酵母蛋白质的4个数据集上,与8种经典的蛋白质复合物检测方法进行对比,验证了该方法的有效性。
文摘累计局部离群因子(cumulative local outlier factor,C_LOF)算法能有效解决数据流中的概念漂移问题和克服离群点检测中的伪装问题,但在处理高维数据时,时间复杂度较高。为有效解决时间复杂度高的问题,提出一种基于投影索引近邻的累计局部离群因子(cumulative local outlier factor based projection indexed nearest neighbor,PINN_C_LOF)算法。使用滑动窗口维护活跃数据点,在新数据到达和旧数据过期时,引入投影索引近邻(projection indexed nearest neighbor,PINN)方法,增量更新窗口中受影响数据点的近邻。实验结果表明,PINN_C_LOF算法在检测高维流数据离群值时,在保持检测精确度的前提下,其时间复杂度较C_LOF算法明显降低。
文摘为解决许多关键节点识别算法在评估网络节点重要性时,忽视节点与其邻居节点间的相互关系,导致对网络鲁棒性和脆弱性的评估结果不准确的问题,提出一种改良的局部加权密度度量方式CPR-WCCN,旨在以较低的计算成本准确识别复杂网络中的关键节点.首先,借助节点间的最短路径长度和数量,定义节点间的通信概率序列.其次,通过结合通信概率和相对熵(Communication Probability and Relative Entropy,CPR),将传统的二元邻接矩阵转化为网络归一化相关矩阵.再次,结合加权聚类系数和邻居节点的影响(Weighted Clustering Coefficients and Neighbor Influence,WCCN),得到改进的考虑邻居影响的局部加权密度.最后,为验证CPRWCCN算法的效果,在故意攻击和随机攻击下进行模拟实验,利用传播模型在4种实际网络上对CPR-WCCN与其他5种算法进行对比分析.实验结果表明:当网络遭受故意攻击,导致前15个关键节点失效时,网络的连通性、效率、最大连接子图以及自然连通性等关键指标较随机攻击出现了更显著的下降;相较于其他5种算法,CPR-WCCN算法表现出最优的整体性能,能够准确且高效地识别出网络中的关键节点.
