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Dark incoherent spatial solitons in logarithmically saturable nonlinear media
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作者 张贻齐 卢克清 +3 位作者 张美志 李可昊 刘爽 张彦鹏 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第6期2359-2363,共5页
This paper studies numerically the dark incoherent spatial solitons propagating in logarithmically saturable nonlinear media by using a coherent density approach and a split-step Fourier approach for the first time. U... This paper studies numerically the dark incoherent spatial solitons propagating in logarithmically saturable nonlinear media by using a coherent density approach and a split-step Fourier approach for the first time. Under odd and even initial conditions, a soliton triplet and a doublet are obtained respectively for given parameters. Simultaneously, coherence properties associated with the soliton triplet and doublet are discussed. In addition, if the values of the parameters are properly chosen, five and four splittings from the input dark incoherent spatial solitons can also form. Lastly, the grayness of the soliton triplet and that of the doublet are studied, in detail. 展开更多
关键词 incoherent spatial solitons coherence length logarithmically nonlinear media
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Analysis of the Metric in Quasicrystals—Linear Response in Logarithmically Periodic Solids
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作者 Antony J. Bourdillon 《Journal of Modern Physics》 2014年第12期1079-1084,共6页
The metric, that enables measurement of structural data from diffraction in quasicrystals, is analyzed. A modified compromise spacing effect is the consequence of scattering of periodic electromagnetic or electron wav... The metric, that enables measurement of structural data from diffraction in quasicrystals, is analyzed. A modified compromise spacing effect is the consequence of scattering of periodic electromagnetic or electron waves by atoms arranged on a geometric grid in an ideal hierarchic structure. This structure is infinitely extensive, uniquely aligned and uniquely icosahedral. The approximate analytic factor that converts the geometric terms base τ, into periodic terms modulo 2π, is . It matches the simulated metric cs=0.947, consistently used in second (Bragg) order, over a wide scale from atomic dimensions to sixth order superclusters. 展开更多
关键词 QUASICRYSTALS METRIC lin-log Response Measurement Logarithmic PERIODIC Hierarchic Structure
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A Logarithmically Improved Regularity Criterion for the Supercritical Quasi-geostrophic Equations in Besov Space 被引量:1
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作者 Sadek GALA 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2017年第3期679-686,共8页
In this paper, we consider the logarithmically improved regularity criterion for the supercritical quasi-geostrophic equation in Besov space B ∞,∞ -r (R2). The result shows that if 0 is a weak solutions satisfies ... In this paper, we consider the logarithmically improved regularity criterion for the supercritical quasi-geostrophic equation in Besov space B ∞,∞ -r (R2). The result shows that if 0 is a weak solutions satisfies ∫ 0 T || θ (·,s)||a/a-r B ∞,∞ -r /(1+ln(e+|| ⊥(·,s)|| L r2) ds〈∞ for some 0〈r〈a and 0〈a〈1,then θ is regular at t = T. In view of the embedding L 2/r M p 2/r B ∞,∞ -r with 2≤p〈2/r and 0≤r〈1, we see that our result extends the results due to [20] and [31]. 展开更多
关键词 quasi-geostrophic equations logarithmical regularity criterion Besov space
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Uniqueness of the Weak Extremal Solution to Biharmonic Equation with Logarithmically Convex Nonlinearities
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作者 LUO Xue 《Journal of Partial Differential Equations》 2010年第4期315-329,共15页
In this note, we investigate the existence of the minimal solution and the uniqueness of the weak extremal (probably singular) solution to the biharmonic equation △2ω=λg(ω)with Dirichlet boundary condition in ... In this note, we investigate the existence of the minimal solution and the uniqueness of the weak extremal (probably singular) solution to the biharmonic equation △2ω=λg(ω)with Dirichlet boundary condition in the unit ball in Rn, where the source term is logarithmically convex. An example is also given to illustrate that the logarithmical convexity is not a necessary condition to ensure the uniqueness of the extremal solution. 展开更多
关键词 Biharmonic equation logarithmically convex nonlinearities extremal solution UNIQUENESS
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气候变化和人类活动下玉米需水量时空特征及未来趋势
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作者 申晓晶 陈猷 +1 位作者 栾文杰 周博 《水土保持学报》 北大核心 2025年第4期243-253,共11页
[目的]为探究气象因素和作物种植面积变化对宁夏引黄灌区玉米需水量的影响及未来玉米需水量变化趋势。[方法]采用Penman-Monteith公式和单作物系数法,计算宁夏引黄灌区玉米需水量并分析其时空变化特征;利用重标极差分析法预测未来作物... [目的]为探究气象因素和作物种植面积变化对宁夏引黄灌区玉米需水量的影响及未来玉米需水量变化趋势。[方法]采用Penman-Monteith公式和单作物系数法,计算宁夏引黄灌区玉米需水量并分析其时空变化特征;利用重标极差分析法预测未来作物需水量和灌溉需水量的时空演变趋势;利用基于偏导数的敏感性分析和对数平均迪氏指数分解方法,探究气象因子和种植面积变化对玉米需水量的影响并确定主要影响因素。[结果]玉米需水量具有较为明显的空间异动性,空间分布趋势呈现由引黄灌区中部向南北两端递增,西南整体低于东北趋势。在对未来需水量预测中,惠农、银川站点的作物未来需水量呈上升趋势。在考虑气象因素对玉米需水量的影响上,相对湿度的敏感系数最高;单位面积作物需水量和灌溉需水量随着最高气温、最低气温、风速、日照时间的上升而增加,随着相对湿度的增加而减少。整个研究期内,作物种植面积变化是导致玉米总需水量变化的主要因素。[结论]玉米种植规模扩大对总需水量的增加有着较大的影响,而气象因子对该时期的总需水量变化作用相对较小。研究结果可为气候变化背景下确定合理的作物种植结构和规模及灌区水资源适应性管理提供决策支持。 展开更多
关键词 气象因子 种植面积变化 需水量 引黄灌区 重标极差分析法(rescaled range analysis R/S) 对数平均迪氏指数分解法(logarithmic mean divisia index LMDI)
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Local Rate of Convergence in the Functional Limit Theorem for Increments of a Fractional Brownian Motion 被引量:1
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作者 LIU Yonghong DING Ding ZHOU Xia 《数学进展》 北大核心 2025年第1期197-211,共15页
In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):104... In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192]. 展开更多
关键词 fractional Brownian motion INCREMENT local functional law of the iterated logarithm large deviation small deviation
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Normalized Solutions for a Logarithmic Schrödinger Equation
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作者 LIU Xiang LEI Chunyu 《数学理论与应用》 2025年第3期96-106,共11页
In this paper,we consider the following logarithmic Schrödinger equation:−Δu+ωu=u log|u|^(2),u∈H^(1)(R^(N)),where N≥3,and ω>0 is a constant.With an auxiliary equation,we obtain the existence of normalized... In this paper,we consider the following logarithmic Schrödinger equation:−Δu+ωu=u log|u|^(2),u∈H^(1)(R^(N)),where N≥3,and ω>0 is a constant.With an auxiliary equation,we obtain the existence of normalized solutions by using the constrained variational method. 展开更多
关键词 Logarithmic Schrödinger equation Normalized solution Constrained variational method Minimization problem
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Blow-up Phenomenon for a Class of Logarithmic Viscoelastic Equations with Delay and Nonlocal Term under Acoustic Boundary Conditions
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作者 DUAN Jisong XIANG Changyong 《数学理论与应用》 2025年第2期76-92,共17页
In this paper,we investigate the blow-up phenomenon for a class of logarithmic viscoelastic equations with delay and nonlocal terms under acoustic boundary conditions.Using the energy method,we prove that nontrivial s... In this paper,we investigate the blow-up phenomenon for a class of logarithmic viscoelastic equations with delay and nonlocal terms under acoustic boundary conditions.Using the energy method,we prove that nontrivial solutions with negative initial energy will blow up in finite time,and provide an upper bound estimate for the blow-up time.Additionally,we also derive a lower bound estimate for the blow-up time. 展开更多
关键词 Finite-time blow-up Logarithmic viscoelastic equation Nonlocal term Damping delay Acoustic boundary condition
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An NOMA-VLC power allocation scheme for multi-user based on sparrow search algorithm
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作者 WANG Xing WANG Haitao +3 位作者 DONG Zhenliang XIONG Yingfei SHI Huili WANG Ping 《Optoelectronics Letters》 2025年第5期278-283,共6页
A non-orthogonal multiple access(NOMA) power allocation scheme on the basis of the sparrow search algorithm(SSA) is proposed in this work. Specifically, the logarithmic utility function is utilized to address the pote... A non-orthogonal multiple access(NOMA) power allocation scheme on the basis of the sparrow search algorithm(SSA) is proposed in this work. Specifically, the logarithmic utility function is utilized to address the potential fairness issue that may arise from the maximum sum-rate based objective function and the optical power constraints are set considering the non-negativity of the transmit signal, the requirement of the human eyes safety and all users' quality of service(Qo S). Then, the SSA is utilized to solve this optimization problem. Moreover, to demonstrate the superiority of the proposed strategy, it is compared with the fixed power allocation(FPA) and the gain ratio power allocation(GRPA) schemes. Results show that regardless of the number of users considered, the sum-rate achieved by SSA consistently outperforms that of FPA and GRPA schemes. Specifically, compared to FPA and GRPA schemes, the sum-rate obtained by SSA is increased by 40.45% and 53.44% when the number of users is 7, respectively. The proposed SSA also has better performance in terms of user fairness. This work will benefit the design and development of the NOMA-visible light communication(VLC) systems. 展开更多
关键词 NOMA logarithmic utility function VLC Sparrow Search Algorithm sparrow search algorithm ssa fairness issue power allocation Sum Rate
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A singular energy line of potential well on evolutionary p-Laplacian with logarithmic source
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作者 Gege LIU Jingxue YIN Yong LUO 《Acta Mathematica Scientia》 2025年第2期363-384,共22页
We consider large-time behaviors of weak solutions to the evolutionary p-Laplacian with logarithmic source of time-dependent coefficient.We find that the weak solutions may neither decay nor blow up,provided that the ... We consider large-time behaviors of weak solutions to the evolutionary p-Laplacian with logarithmic source of time-dependent coefficient.We find that the weak solutions may neither decay nor blow up,provided that the initial data u(·,t_(0))is on the Nehari manifold N:={v∈W_(0)^(1,p)(Ω):I(v,to)=0,||▽v||P^(P)≠0}.This is quite different from the known results that the weak solutions may blow up as,u(·,to)∈N^(+):={v∈W_(0)^(1,p)(Ω):I(v,t_(0))<0}and weak solutions may decay as u(·,t_(0))∈N^(+):={v∈W_(0)^(1,p)(Ω):I(v,t_(0))>0}. 展开更多
关键词 logarithmic source singular energy line large-time behavior
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对数的换底公式题型例讲
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作者 王有就 《中学生数理化(高一数学)》 2025年第11期3-3,共1页
一、求未知数的值例1若log51/3·log_(3)6·log_(6)x=2,求x的值。解:因为log51/3·log_(3)6·log_(6)x=-lg3/ lg5·lg6/lg3·lgx/lg6=2,所以lgx=-2lg5,所以x=5^(-2)=1/25。
关键词 logarithmic base change formula LOGARITHM
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水文干旱对气象干旱的响应及其临界条件 被引量:28
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作者 吴杰峰 陈兴伟 高路 《灾害学》 CSCD 2017年第1期199-204,共6页
流域水文干旱对气象干旱的响应是干旱研究的重要问题。以东南沿海晋江流域为例,选取1960-2010年逐月实测降水和径流数据,采用标准化降水指数(Standardized Precipitation Index,SPI)和标准化径流指数(Standardized Streamflow Index,SSI... 流域水文干旱对气象干旱的响应是干旱研究的重要问题。以东南沿海晋江流域为例,选取1960-2010年逐月实测降水和径流数据,采用标准化降水指数(Standardized Precipitation Index,SPI)和标准化径流指数(Standardized Streamflow Index,SSI)两个干旱指数(分别代表气象干旱和水文干旱)及游程理论对流域主要干旱事件特征进行识别,应用Logarithm函数,建立水文干旱对气象干旱特征的响应关系模型,从而进一步分析了水文干旱对气象干旱的响应关系,并提出了气象干旱演进为水文干旱临界条件的概念。结果表明,多时间尺度的SPI与SSI指数可以有效反映晋江流域气象、水文干旱历时及烈度,用Logarithm函数可以比较好地建立晋江流域水文干旱对气象干旱的响应关系模型,得到气象干旱演进为水文干旱的临界条件为气象干旱历时1.45个月、烈度0.8,该模型的建立也为基于气象干旱监测实现水文干旱预警提供了可能。 展开更多
关键词 干旱指数 水文干旱 气象干旱 响应关系 Logarithm函数 临界条件 晋江流域
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红枣气体射流冲击干燥特性及干燥模型 被引量:10
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作者 王立霞 兰昊 +4 位作者 郑倩雨 郑珊珊 田呈瑞 田洪磊 肖旭霖 《食品科学技术学报》 EI CAS CSCD 北大核心 2022年第2期131-140,共10页
由于红枣收获后品质快速下降,探讨适合红枣的加工方法以便延长红枣的保藏期非常重要。探究了干制条件对红枣气体射流干燥特性的影响,以便提高干制红枣品质,缩短干制时间,获取干燥活化能,优选干燥模型。选用自制气体射流冲击干燥设备干... 由于红枣收获后品质快速下降,探讨适合红枣的加工方法以便延长红枣的保藏期非常重要。探究了干制条件对红枣气体射流干燥特性的影响,以便提高干制红枣品质,缩短干制时间,获取干燥活化能,优选干燥模型。选用自制气体射流冲击干燥设备干制红枣,研究风速(8.5、10.0、12.0 m/s)、风温{60、65、70℃,变量[70℃(5 h)+65℃(8 h)+55℃]}对红枣水分比和干燥速率、水分有效扩散系数及活化能的影响,通过DPS数据统计软件对8个干燥模型(Lewis、Page、Modified Page、Wang&Singh、Henderson&Pabis、Approximation of diffusion、Logarithmic、Simplified Fick's diffusion)进行拟合筛选。与大多数食品材料的干燥特性一致,红枣的气体射流冲击干燥过程主要为降速干燥。温度对整个干燥过程中参数的变化影响较大,温度越高,水分扩散越快,水分比下降越快,干燥速率越高。最高有效扩散系数为1.22133×10^(-9) m^(2)/s,所需最小活化能为10.39 kJ/mol。使用8个模型进行拟合,研究发现Logarithmic模型的参数系数(R^(2))值为0.999801,均方根误差(RMSE)值为0.002913,卡方值(χ^(2))为9.332000×10^(-6),该模型为描述红枣气体射流冲击干燥的最优模型。温度与风速均对干燥曲线、干燥速率曲线、水分有效扩散系数和活化能有影响,在温度70℃(5 h)+65℃(8 h)+55℃,风速12.0 m/s的条件下干燥效果较佳。 展开更多
关键词 红枣 气体射流冲击 干燥特性 干燥模型 Logarithmic模型
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仿生组装淫羊藿苷-壳聚糖/羟基磷灰石骨修复材料的体外释药行为 被引量:5
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作者 吴涛 吴金辉 +4 位作者 郑国栋 卢志勤 曾海燕 吕军 邢建洲 《中国组织工程研究》 CAS CSCD 2014年第52期8399-8404,共6页
背景:淫羊藿苷性质稳定,可促进成骨细胞的增殖,可作为一种骨诱导活性因子用于骨组织工程的研究。目的:探讨淫羊藿苷-壳聚糖/羟基磷灰石骨修复材料的体外释药行为。方法:将载药量分别为10-7,10-6,10-5mol的淫羊藿苷-壳聚糖/羟基磷灰石材... 背景:淫羊藿苷性质稳定,可促进成骨细胞的增殖,可作为一种骨诱导活性因子用于骨组织工程的研究。目的:探讨淫羊藿苷-壳聚糖/羟基磷灰石骨修复材料的体外释药行为。方法:将载药量分别为10-7,10-6,10-5mol的淫羊藿苷-壳聚糖/羟基磷灰石材料置于盛有PBS的密闭玻璃离心管中,37℃恒温振荡,分别于1,2,3,10,15,20,30,60,90 d定时收集全部溶液进行超高效液相色谱检测。通过精密度实验、重复性实验、加样回收率实验、稳定性实验考查实验方法的精密度、灵敏度和淫羊藿苷的稳定性,通过标准曲线换算供试品每次释药量,并将其进行累积绘制成释药曲线,采用Logarithmic模型对释药行为进行曲线拟合。结果与结论:实验方法的精密度、准确度与重复性良好;淫羊藿苷性质稳定,可在室温避光的环境下保存至少90 d;在1-2 000 ng质量范围内,淫羊藿苷的色谱峰面积与进样量之间呈良好的线性关系。释药初期(0-3 d),药物从支架材料中突释,约达载药量的25%,而后释药速度迅速下降,至第20天有40%-60%的药物释出,之后以低速持续释放,90 d后仍有部分药物存留于支架材料中。3种载药量淫羊藿苷-壳聚糖/羟基磷灰石材料的释药行为遵循一级方程模型,所有模型均有统计学意义(P=0)。表明仿生组装淫羊藿苷-壳聚糖/羟基磷灰石骨修复材料对淫羊藿苷具有良好的控释效果,其体外释药行为符合一级方程。 展开更多
关键词 生物材料 缓释材料 淫羊藿苷 壳聚糖 羟基磷灰石 支架材料 控释 Logarithmic模型 一级方程 组织工程 国家自然科学基金
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MDS-MAP算法在不同传播模型中定位误差的比较 被引量:4
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作者 许红艳 王经卓 +1 位作者 董自健 裴菊静 《淮海工学院学报(自然科学版)》 CAS 2012年第1期15-19,共5页
主要介绍了MDS-MAP算法在通过4种不同传播模型时定位误差的不同,通过仿真可以看到MDS-MAP算法在各个传播模型中的定位误差图。从仿真结果可以得出,在环境好的情况下,规则模型与不规则模型的定位误差相差不大,当环境变化时,不规则传播模... 主要介绍了MDS-MAP算法在通过4种不同传播模型时定位误差的不同,通过仿真可以看到MDS-MAP算法在各个传播模型中的定位误差图。从仿真结果可以得出,在环境好的情况下,规则模型与不规则模型的定位误差相差不大,当环境变化时,不规则传播模型比规则传播模型更能适应恶劣的环境。介绍了两种情况,随着环境的改变,传播模型相关参数也会有所改变进而影响定位误差的变化。 展开更多
关键词 MDS-MAP算法 Regular模型 Logarithmic Attenuation模型 DOI模型 RIM模型
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New signature scheme based on two cryptographic assumptions 被引量:2
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作者 郑明辉 崔国华 《Journal of Southeast University(English Edition)》 EI CAS 2007年第3期461-464,共4页
In order to improve the security of the signature scheme, a digital signature based on two hard-solved problems is proposed. The discrete logarithm problem and the factoring problem are two well known hard- solved mat... In order to improve the security of the signature scheme, a digital signature based on two hard-solved problems is proposed. The discrete logarithm problem and the factoring problem are two well known hard- solved mathematical problems. Combining the E1Gamal scheme based on the discrete logarithm problem and the OSS scheme based on the factoring problem, a digital signature scheme based on these two cryptographic assumptions is proposed. The security of the proposed scheme is based on the difficulties of simultaneously solving the factoring problem and the discrete logarithm problem. So the signature scheme will be still secure under the situation that any one of the two hard-problems is solved. Compared with previous schemes, the proposed scheme is more efficient in terms of space storage, signature length and computation complexities. 展开更多
关键词 digital signature SECURITY factoring problem discrete logarithm problem
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Static CMOS Implementation of Logarithmic Skip Adder
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作者 贾嵩 刘飞 +2 位作者 刘凌 陈中建 吉利久 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第11期1159-1165,共7页
Circuit design of 32 bit logarithmic skip adder (LSA) is introduced to implement high performance,low power addition.ELM carry lookahead adder is included into groups of carry skip adder and the hybrid structure cost... Circuit design of 32 bit logarithmic skip adder (LSA) is introduced to implement high performance,low power addition.ELM carry lookahead adder is included into groups of carry skip adder and the hybrid structure costs 30% less hardware than ELM.At circuit level,a carry incorporating structure to include the primary carry input in carry chain and an 'and xor' structure to implement final sum logic in 32 bit LSA are designed for better optimization.For 5V,1μm process,32 bit LSA has a critical delay of 5 9ns and costs an area of 0 62mm 2,power consumption of 23mW at 100MHz.For 2 5V,0 25μm process,critical delay of 0 8ns,power dissipation of 5 2mW at 100MHz is simulated. 展开更多
关键词 logarithmic skip carry incorporating sum logic circuit design
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个体风险模型中总索赔额分布函数的估值问题 被引量:1
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作者 赵丽霞 《长春工业大学学报》 CAS 2011年第2期191-194,共4页
在假定投保人数服从Logarithmic分布的基础上,研究了个体风险模型中总索赔额分布函数的估值问题,给出了总索赔额分布函数的上、下界,为保险公司纯保费的厘定提供了一定的参考价值。
关键词 风险模型 Logarithmic分布 估值
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LEVEL SETS AND EQUIVALENCES OF MORAN-TYPE SETS
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作者 杜亚丽 苗俊杰 吴敏 《Acta Mathematica Scientia》 SCIE CSCD 2016年第5期1343-1357,共15页
In the paper, we consider Moran-type sets E;given by sequences {a;};and{n;};. we prove that E;may be decompose into the disjoint union of level sets. Moreover,we define three type of equivalence between two dimension ... In the paper, we consider Moran-type sets E;given by sequences {a;};and{n;};. we prove that E;may be decompose into the disjoint union of level sets. Moreover,we define three type of equivalence between two dimension functions associated to two Morantype sets, respectively, and we classify Moran-type sets by these equivalent relations. 展开更多
关键词 Moran-type sets dimension function level set logarithmical equivalence
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An Integral Inequality and Polya-Szego Inequality
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作者 朱永娥 侯海军 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第3期412-414,共3页
The paper brings an important integral inequality, which includes the famous Polya-Szego inequality and the logarithmical-arithmetic mean inequality as special cases.
关键词 INTEGRAL INEQUALITY arithmetical mean logarithmical mean
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