The early universe inflation is well known as a promising theory to explain the origin of large-scale structure of universe and to solve the early universe pressing problems. For a reasonable inflation model, the pote...The early universe inflation is well known as a promising theory to explain the origin of large-scale structure of universe and to solve the early universe pressing problems. For a reasonable inflation model, the potential during inflation must be very flat, at least, in the direction of the inflaton. To construct the inflaton potential all the known related astrophysics observations should be included. For a general tree-level hybrid inflation potential, which is notdiscussed fully so far, the parameters in it are shown how to be constrained via the astrophysics data observed and to be obtained to the expected accuracy, and to be consistent with cosmology requirements.展开更多
Given a simple connected graph G, we consider two iterated constructions associated with G: Fk (G) and Rk (G) . In this paper, we completely obtain the normalized Laplacian spectrum of Fk (G) and Rk (G) , with k ≥2, ...Given a simple connected graph G, we consider two iterated constructions associated with G: Fk (G) and Rk (G) . In this paper, we completely obtain the normalized Laplacian spectrum of Fk (G) and Rk (G) , with k ≥2, respectively. As applications, we derive the closed-formula of the multiplicative degree-Kirchhoff index, the Kemeny’s constant, and the number of spanning trees of Fk?(G)? , Rk?(G) , r-iterative graph ,Frk?(G)? and r-iterative graph , where k?≥2 and r?≥1 . Our results extend those main results proposed by Pan et al. (2018), and we provide a method to characterize the normalized Laplacian spectrum of iteratively constructed complex graphs.展开更多
How to design an energy-efficient algorithm to maximize the network lifetime in complicated scenarios is a critical problem for heterogeneous wireless sensor networks(HWSN).In this paper, a clustering-tree topology co...How to design an energy-efficient algorithm to maximize the network lifetime in complicated scenarios is a critical problem for heterogeneous wireless sensor networks(HWSN).In this paper, a clustering-tree topology control algorithm based on the energy forecast(CTEF) is proposed for saving energy and ensuring network load balancing, while considering the link quality, packet loss rate, etc. In CTEF, the average energy of the network is accurately predicted per round(the lifetime of the network is denoted by rounds) in terms of the difference between the ideal and actual average residual energy using central limit theorem and normal distribution mechanism, simultaneously. On this basis, cluster heads are selected by cost function(including the energy, link quality and packet loss rate) and their distance.The non-cluster heads are determined to join the cluster through the energy, distance and link quality. Furthermore, several noncluster heads in each cluster are chosen as the relay nodes for transmitting data through multi-hop communication to decrease the load of each cluster-head and prolong the lifetime of the network. The simulation results show the efficiency of CTEF. Compared with low-energy adaptive clustering hierarchy(LEACH), energy dissipation forecast and clustering management(EDFCM) and efficient and dynamic clustering scheme(EDCS)protocols, CTEF has longer network lifetime and receives more data packets at base station.展开更多
近几十年中随着全球气候环境变化,青藏高原处于变暖变湿过程之中,植被生长发生了显著变化。基于卫星遥感归一化植被指数(NDVI),采用增强回归树模型(BRT)定量分析了1982—2015年影响青藏高原植被生长变化的主要环境因子的相对重要性。结...近几十年中随着全球气候环境变化,青藏高原处于变暖变湿过程之中,植被生长发生了显著变化。基于卫星遥感归一化植被指数(NDVI),采用增强回归树模型(BRT)定量分析了1982—2015年影响青藏高原植被生长变化的主要环境因子的相对重要性。结果表明:(1)整个青藏高原生长季(6—9月份)空间平均NDVI和降水呈上升趋势(1.265×10^(-4)a^(-1)和0.746 mm/a,P>0.05);温度和土壤湿度呈现显著增加趋势(0.048℃/a和3.954×10^(-4)a^(-1),P<0.01);向下短波辐射显著减小(-0.070 W m^(-2)a^(-1),P<0.01)。(2)青藏高原34.0%地区NDVI表现出显著增加趋势,主要分布在青藏高原北部大部分地区和西部部分区域;9.2%地区NDVI呈显著减小趋势,主要位于青藏高原东部地区。(3)土壤湿度、年均温、年降水和向下短波辐射分别解释了生长季NDVI变化的42%,19%,10%和9%。(4)土壤湿度、年均温、年降水和向下短波辐射对青藏高原植被生长动态影响的相对大小具有明显的空间差异特征。温度上升是青藏高原东北部和中部部分地区NDVI变化的首要因素(相对贡献率>40%),而土壤湿度增加是青藏高原西南部及东南部分地区NDVI变化的主要原因(相对贡献率>50%)。总体上,温度上升及由此所导致的冰冻圈消融引起的土壤含水量上升是近几十年青藏高原植被生长动态快速变化的主要原因。展开更多
针对响应服从非正态分布和模型不确定性的稳健参数设计问题,在Polya树混合建模的框架下,构建了一种半参数分层贝叶斯响应曲面模型,并在此基础上实现了稳健参数设计。首先,建立贝叶斯半参数模型,并获得模型各参数的后验分布;其次,运用马...针对响应服从非正态分布和模型不确定性的稳健参数设计问题,在Polya树混合建模的框架下,构建了一种半参数分层贝叶斯响应曲面模型,并在此基础上实现了稳健参数设计。首先,建立贝叶斯半参数模型,并获得模型各参数的后验分布;其次,运用马尔可夫链蒙特卡罗(Markov chain Monte Carlo,MCMC)算法获得各参数的估计值;然后,基于此构建期望质量损失函数,并利用混合遗传算法全局寻优,获得可控因子的最优设置;最后,通过数值模拟研究和实际案例验证了所提方法的有效性。所提方法能有效解决小样本数据以及模型不确定性对优化结果影响的问题,从而能够获得更稳健可靠的可控因子最优设置。展开更多
文摘The early universe inflation is well known as a promising theory to explain the origin of large-scale structure of universe and to solve the early universe pressing problems. For a reasonable inflation model, the potential during inflation must be very flat, at least, in the direction of the inflaton. To construct the inflaton potential all the known related astrophysics observations should be included. For a general tree-level hybrid inflation potential, which is notdiscussed fully so far, the parameters in it are shown how to be constrained via the astrophysics data observed and to be obtained to the expected accuracy, and to be consistent with cosmology requirements.
文摘Given a simple connected graph G, we consider two iterated constructions associated with G: Fk (G) and Rk (G) . In this paper, we completely obtain the normalized Laplacian spectrum of Fk (G) and Rk (G) , with k ≥2, respectively. As applications, we derive the closed-formula of the multiplicative degree-Kirchhoff index, the Kemeny’s constant, and the number of spanning trees of Fk?(G)? , Rk?(G) , r-iterative graph ,Frk?(G)? and r-iterative graph , where k?≥2 and r?≥1 . Our results extend those main results proposed by Pan et al. (2018), and we provide a method to characterize the normalized Laplacian spectrum of iteratively constructed complex graphs.
基金supported by National Natural Science Foundation of China(61304256)Zhejiang Provincial Natural Science Foundation of China(LQ13F030013)+4 种基金Project of the Education Department of Zhejiang Province(Y201327006)Young Researchers Foundation of Zhejiang Provincial Top Key Academic Discipline of Mechanical Engineering and Zhejiang Sci-Tech University Key Laboratory(ZSTUME01B15)New Century 151 Talent Project of Zhejiang Province521 Talent Project of Zhejiang Sci-Tech UniversityYoung and Middle-aged Talents Foundation of Zhejiang Provincial Top Key Academic Discipline of Mechanical Engineering
文摘How to design an energy-efficient algorithm to maximize the network lifetime in complicated scenarios is a critical problem for heterogeneous wireless sensor networks(HWSN).In this paper, a clustering-tree topology control algorithm based on the energy forecast(CTEF) is proposed for saving energy and ensuring network load balancing, while considering the link quality, packet loss rate, etc. In CTEF, the average energy of the network is accurately predicted per round(the lifetime of the network is denoted by rounds) in terms of the difference between the ideal and actual average residual energy using central limit theorem and normal distribution mechanism, simultaneously. On this basis, cluster heads are selected by cost function(including the energy, link quality and packet loss rate) and their distance.The non-cluster heads are determined to join the cluster through the energy, distance and link quality. Furthermore, several noncluster heads in each cluster are chosen as the relay nodes for transmitting data through multi-hop communication to decrease the load of each cluster-head and prolong the lifetime of the network. The simulation results show the efficiency of CTEF. Compared with low-energy adaptive clustering hierarchy(LEACH), energy dissipation forecast and clustering management(EDFCM) and efficient and dynamic clustering scheme(EDCS)protocols, CTEF has longer network lifetime and receives more data packets at base station.
文摘近几十年中随着全球气候环境变化,青藏高原处于变暖变湿过程之中,植被生长发生了显著变化。基于卫星遥感归一化植被指数(NDVI),采用增强回归树模型(BRT)定量分析了1982—2015年影响青藏高原植被生长变化的主要环境因子的相对重要性。结果表明:(1)整个青藏高原生长季(6—9月份)空间平均NDVI和降水呈上升趋势(1.265×10^(-4)a^(-1)和0.746 mm/a,P>0.05);温度和土壤湿度呈现显著增加趋势(0.048℃/a和3.954×10^(-4)a^(-1),P<0.01);向下短波辐射显著减小(-0.070 W m^(-2)a^(-1),P<0.01)。(2)青藏高原34.0%地区NDVI表现出显著增加趋势,主要分布在青藏高原北部大部分地区和西部部分区域;9.2%地区NDVI呈显著减小趋势,主要位于青藏高原东部地区。(3)土壤湿度、年均温、年降水和向下短波辐射分别解释了生长季NDVI变化的42%,19%,10%和9%。(4)土壤湿度、年均温、年降水和向下短波辐射对青藏高原植被生长动态影响的相对大小具有明显的空间差异特征。温度上升是青藏高原东北部和中部部分地区NDVI变化的首要因素(相对贡献率>40%),而土壤湿度增加是青藏高原西南部及东南部分地区NDVI变化的主要原因(相对贡献率>50%)。总体上,温度上升及由此所导致的冰冻圈消融引起的土壤含水量上升是近几十年青藏高原植被生长动态快速变化的主要原因。
文摘针对响应服从非正态分布和模型不确定性的稳健参数设计问题,在Polya树混合建模的框架下,构建了一种半参数分层贝叶斯响应曲面模型,并在此基础上实现了稳健参数设计。首先,建立贝叶斯半参数模型,并获得模型各参数的后验分布;其次,运用马尔可夫链蒙特卡罗(Markov chain Monte Carlo,MCMC)算法获得各参数的估计值;然后,基于此构建期望质量损失函数,并利用混合遗传算法全局寻优,获得可控因子的最优设置;最后,通过数值模拟研究和实际案例验证了所提方法的有效性。所提方法能有效解决小样本数据以及模型不确定性对优化结果影响的问题,从而能够获得更稳健可靠的可控因子最优设置。
