EVENTUAL STABILITY OF IMPULSIVE DIFFERENTIAL SYSTEMS

In this article, criteria of eventual stability are established for impulsive differential systems using piecewise continuous Lyapunov functions. The sufficient conditions that are obtained significantly depend on the moments of impulses. An example is discussed to illustrate the theorem.

RBF-FD Method for Some Dispersive Wave Equations and Their Eventual Periodicity

In this paper,we approximate the solution and also discuss the periodic behavior termed as eventual periodicity of solutions of(IBVPs)for some dispersive wave equations on a bounded domain corresponding to periodic forcing.The constructed numerical scheme is based on radial kernels and local in nature like finite difference method.The temporal variable is executed through RK4 scheme.Due to the local nature and sparse differentiation matrices our numerical scheme efficiently recovers the solution.The results achieved are validated and examined with other methods accessible in the literature.

Eventually vanished solutions of a forced Liénard system

In this paper, we aim to find eventually vanished solutions, a special class of bounded solutions which tend to 0 as t → ±∞）, to a Lienard system with a time-dependent force. Since it is not a Hamiltonian system with small perturbations, the well-known Melnikov method is not applicable to the determination of the existence of eventually vanished solutions. We use a sequence of periodically forced systems to approximate the considered system, and find their periodic solutions. Difficulties caused by the non- Hamiltonian form are overcome by applying the Schauder＇s fixed point theorem. We show that the sequence of the periodic solutions has an accumulation giving an eventually vanished solution of the forced Lienard system.

A Convergence Theorem for Set-valued Eventual Supermartingle

it In this paper, the properties of set-valued Eventual Supermartingle are discussed. The main result is that suppose {Fn, n ≥ 1） Lfc^1（X） be set-valued Eventual Supermartingle, ifsupE（d（0,Fτ）） 〈 ∞, then Fn →KF and SF^1≠φ, here T is the sets of all T bounded stopping times.

Relation Between the Eventual Continuity and the E-property for Markov-Feller Semigroups

We investigate some relations between two kinds of semigroup regularities, namely the e-property and the eventual continuity, both of which contribute to the ergodicity for Markov processes on Polish spaces.More precisely, we prove that for Markov-Feller semigroup in discrete time and stochastically continuous MarkovFeller semigroup in continuous time, if there exists an ergodic measure whose support has a nonempty interior,then the e-property is satisfied on the interior of the support. In particular, it implies that, restricted on the support of each ergodic measure, the e-property and the eventual continuity are equivalent for the discrete-time and the stochastically continuous continuous-time Markov-Feller semigroups.

Several Dynamics of Dynamical Systems with the Eventual Shadowing Property

In this article,we provide some sufficient conditions for the dynamical systems with the eventual shadowing property to have positive topological entropy and several equivalent conditions for the dynamical systems with the eventual shadowing property to be mixing.

Eventual Leader Election with Weak Assumptions on Initial Knowledge,Communication Reliability,and Synchrony

This paper considers the eventual leader election problem in asynchronous message-passing systems where an arbitrary number t of processes can crash（t〈n,where n is the total number of processes）.It considers weak assumptions both on the initial knowledge of the processes and on the network behavior.More precisely,initially,a process knows only its identity and the fact that the process identities are different and totally ordered（it knows neither n nor t）.Two eventual leader election protocols and a lower bound are presented.The first protocol assumes that a process also knows a lower bound α on the number of processes that do not crash.This protocol requires the following behavioral properties from the underlying network：the graph made up of the correct processes and fair lossy links is strongly connected,and there is a correct process connected to（n〈f）-α other correct processes（where f is the actual number of crashes in the considered run） through eventually timely paths（paths made up of correct processes and eventually timely links）.This protocol is not communication-efficient in the sense that each correct process has to send messages forever.The second protocol is communication-efficient：after some time,only the final common leader has to send messages forever.This protocol does not require the processes to know α,but requires stronger properties from the underlying network：each pair of correct processes has to be connected by fair lossy links（one in each direction）,and there is a correct process whose n〈f-1 output links to the rest of correct processes have to be eventually timely.A matching lower bound result shows that any eventual leader election protocol must have runs with this number of eventually timely links,even if all processes know all the processes identities.In addition to being communication-efficient,the second protocol has another noteworthy efficiency property,namely,be the run finite or infinite,all the local variables and message fields have a finite domain in the run.

On the Eventual Shadowing Property and Eventually Shadowable Point of Set-valued Dynamical Systems

The authors introduce the concepts of the eventual shadowing property and eventually shadowable point for set-valued dynamical systems and prove that a set-valued dynamical system has the eventual shadowing property if and only if every point in the phase space is eventually shadowable;every chain transitive set-valued dynamical system has either the eventual shadowing property or no eventually shadowable points;and a set-valued dynamical system admits an eventually shadowable point if and only if it admits a minimal eventually shadowable point.Moreover,it is proved that a set-valued dynamical system with the eventual shadowing property is chain mixing if and only if it is mixing and if and only if it has the specification property.

观赏植物糖转运蛋白研究进展

观赏植物因其花、叶、果实等具有良好的观赏价值而在环境美化中得到广泛应用。糖转运蛋白在观赏植物生长发育、开花结实以及逆境胁迫响应等方面发挥重要作用,因此,研究糖转运蛋白对观赏植物产生的影响具重要意义。单糖转运蛋白、蔗糖转运蛋白和糖外排转运蛋白是目前植物中发现的3大类糖转运蛋白。本文对这3类糖转运蛋白成员的分类及基本特性进行了比较和讨论,重点介绍了观赏植物中糖转运蛋白功能和调控的最新研究进展,以期为今后利用基因工程技术改良观赏植物并提高其观赏性及适应性提供理论依据。

An efficient and highly available framework of data recency enhancement for eventually consistent data stores

Data items are usually replicated in modem dis- tributed data stores to obtain high performance and avail- ability. However, the availability-consistency and latency- consistency trade-offs exist in data replication, thus system designers intend to choose weak consistency models, such as eventual consistency, which may result in stale reads. Since stale data items may lead to serious application semantic problems, we consider how to increase the probability of data recency which provides a uniform view on recent versions of data items for all clients. In this work, we propose HARP, a framework that can enhance data recency of eventually con- sistent distributed data stores in an efficient and highly avail- able way. Through detecting possible stale reads under fail- ures or not, HARP can perform reread operations to elim- inate stale results only when needed based on our analysis on write/read processes. We also present solutions on how to deal with some practical anomalies in HARP, including de- layed, reordered and dropped messages and clock drift, and show how to extend HARP to multiple datacenters. Finally we implement HARP based on Cassandra, and the experi- ments show that HARP can effectively eliminate stale reads, with a low overhead （less than 6.9%） compared with original eventually consistent Cassandra.

功能视角下“NV了”与“VN了”句式对比研究

本文重点考察汉语中的“NV了”与“VN了”句式,从结构、意义和功能等方面对比两者异同。研究表明,“NV了”是话题结构,即话题-述题,动名结合松散,表现出行为性和及物性,表征行为活动。“VN了”则缺少话题,动词唯一的参与者被压制至动词之后,动名结合紧密,甚至词汇化,表现出非人称性、事件性和作格性,表征事件与事件类存在句的特点相吻合。二者相比,“VN了”句式的成立受到更多约束。这体现并印证了汉语的类型特征,即汉语是话题突出型语言以主宾格模式为主导,及物性为主,作格性为辅。

A Note on Equilibrium of Eventually Strongly Monotone Skew-product Semiflows

In this paper, we show that for an eventually strongly monotone skew-product semiflow τ, the strict ordering on Ec （the set consisting of continuous equilibria of τ） implies the strong one.

甜瓜SWEET基因家族的全基因组鉴定及生物信息学分析

糖外排转运子(sugars will eventually be exported transporter,SWEET)是一类新型的糖转运蛋白,其在植物生长发育、植物与病原体互作以及植物胁迫耐受性方面都起着重要作用。基于甜瓜中还未有该家族基因的相关报道,本研究开展CmSWEET的全基因组鉴定和生物信息学分析。通过同源性搜索,总共鉴定到17个甜瓜CmSWEET基因。这些基因分布于甜瓜8条染色体上,具有典型的MtN3/saliva结构域。系统发育树将拟南芥、黄瓜和甜瓜的SWEET蛋白分为4个进化分支,其中亚族Ⅲ是甜瓜和黄瓜独有的亚族。基因启动子区域的顺式作用元件显示,CmSWEET含有许多与植物激素和应激相关的调节元件,暗示了CmSWEET在参与调节甜瓜生长发育以及环境适应性方面有重要作用。基因表达量分析表明,大部分CmSWEET基因在花(雌花和雄花)和根中高表达,部分CmSWEET基因在果实发育时期表达量较高。此外,RNA-Seq结果暗示,CmSWEET基因可能参与对尖孢镰刀菌和白粉病菌侵染的抗性响应。本研究为今后探究CmSWEET蛋白在甜瓜生长发育过程以及响应生物和非生物胁迫中的分子功能奠定了坚实的基础。

Elsa:一种面向跨区域架构的无协调分布式键值存储系统

作为具备高性能和高可伸缩性的分布式存储解决方案,键值存储系统近年来被广泛采用,例如Redis、MongoDB、Cassandra等.分布式存储系统中广泛使用的多副本机制一方面提高了系统吞吐量和可靠性,但同时也增加了系统协调和副本一致性的额外开销.对于跨域分布式系统来说,远距离的副本协调开销甚至可能成为系统的性能瓶颈,降低系统的可用性和吞吐量.提出分布式键值存储系统Elsa,这是一种面向跨区域架构的无协调键值存储系统.Elsa在保证高性能和高可拓展性的基础上,采用无冲突备份数据结构(CRDT)技术来无协调的保证副本间的强最终一致性,降低了系统节点间的协调开销.在阿里云上构建了跨4数据中心8节点的跨区域分布式环境,进行了大规模分布式性能对比实验,实验结果表明:在跨域的分布式环境下,对于高并发争用的负载,Elsa系统的性能具备明显的优势,最高达到MongoDB集群的7.37倍,Cassandra集群的1.62倍.

基于字符串匹配算法的业务流程低频日志噪声过滤方法

过程挖掘领域关注的是对业务流程执行所产生的数据的分析,旨在从数据中提取可操作的过程知识。模型的低频日志中可能存在一些噪声,导致分析受到负面影响,由此提出了一种基于频率变化规则及字符串匹配方法从低频的事件日志中识别并过滤噪声的方法。首先,基于直接跟随图和最终跟随图,根据频率变化规则,从事件日志中识别无效的直接活动对序列集合。然后,结合改进的字符串匹配算法,根据直接跟随图的直接关系与事件日志的迹的序列片段的对应关系,将无效活动序列与低频日志迹进行字符串匹配,从而过滤日志中的噪声,优化挖掘模型。最后,通过具体的案例分析及仿真实验,验证了该方法的有效性。

“被”的语法属性及事件投射特征--基于《朱子语类》中的特殊“被”字句

“被”字句中“被”的语法属性历来有很大争议,近代汉语特殊“被”字句的事实考察支持动词说。动词“被”在句法上不断扩容,它所管辖的成分在历时上经历了不断泛化的过程:名词—及物动词—不及物动词—形容词—小句—复句形式。“被”在语义上表示“遭受/经历”义,主语在语义角色上表现为历事和受影响者,其后所带的是一个事件。及物动词被动句和非及物动词被动句在事件投射上的差异体现在:前者不仅投射结果状态,同时在投射中编码了事件的动态过程,强调结果与过程之间的“遭受”关系;后者所表达的事件则是直接投射内论元的结果状态,凸显的是事件引起的结果和特征,“遭受”的动态过程隐藏在词汇体中。

新形势下的核安全与辐射安全对策

随着核资源广泛利用,核安全也越来越受到人们的关注。笔者在新的安全形势下,从实际情况出发,分析了我国核和辐射安全现状,特别是近年来,世界范围内核恐怖事件的潜在危险在不断增加,核设施和辐射设施在运行过程中,由于失误等原因引起事故的可能性是客观存在的,在现代战争条件下,核设施极有可能成为敌人精确打击的战略目标,因此,核安全和辐射安全面临着新的挑战。针对核安全和辐射安全存在的隐患,应从应急组织体系建设、监测系统开发、人员培训、基本信息数据库的建立、应急决策支持系统开发、完善法规、加强国际合作等方面,提出了改善我国核安全与辐射安全现状的相关对策,以不断提高我国核安全和辐射安全的水平。

一种云存储环境下的安全网盘系统

随着云存储的迅速推广,有越来越多的用户开始使用网盘系统存放数据.然而,最新的研究结果却表明:现有网盘系统普遍存在着安全漏洞.近年来,网盘泄漏用户数据的事件更是印证了这些漏洞的存在.为此,提出一种云存储环境下的安全网盘系统架构,并在此架构上设计实现了CorsBox系统.CorsBox系统采用一种基于目录树的同步方式,在提高安全性的同时保证了共享操作的最终一致性,为用户提供访问权限控制、大数据断点传输、版本控制等功能.测试结果表明,安全机制仅给系统带来了很少的额外开销,说明CorsBox系统在提高数据安全性的同时依然具有良好的性能.

一类具有连续变量的二阶非线性中立型时滞差分方程的振动性

用分析的方法研究了一类具有连续变量的二阶非线性中立型时滞差分方程解的振动性,给出了该类方程所有有界解振动和方程振动的几个充分条件。

高阶中立型差分方程的振动性及其非振动解的渐近性态

本文给出了高阶非线性中立型时滞差分方程Δd(x(n - P(n) x(n - k) ) +g(n) f (x(m - l) ) =0振动的一个充分条件 ,同时又给出该方程的非振动解趋于零的判据 .