The Distribution Search:An O(n) Expected Time Search

Provided an algorithm for the distribution search and proves the time complexity of the algorithm. This algorithm uses a mathematical formula to search n elements in the sequence of n elements in O(n)expected time,and experimental reesult proves that distribution search is superior to binary search.

A Note on the Expectation Value of Time

In this note, the expectation value of time based on quantum mechanics formalism is derived. It is found that the expectation value of time does not depend on space.

基于稀疏贝叶斯学习的GFDM系统联合迭代信道估计与符号检测

针对当前广义频分复用(Generalized Frequency Division Multiplexing,GFDM)系统时变信道估计精度低的问题,提出基于稀疏贝叶斯学习的GFDM系统联合信道估计与符号检测算法.具体地,采用无干扰导频插入的GFDM多重响应信号模型,在稀疏贝叶斯学习框架下,结合期望最大化算法(Expectation-Maximization,EM)和卡尔曼滤波与平滑算法实现块时变信道的最大似然估计;基于信道状态信息的估计值进行GFDM符号检测,并通过信道估计与符号检测的迭代处理逐步提高信道估计与符号检测的精度.仿真结果表明,所提算法能够获得接近完美信道状态信息条件下的误码率性能,且具有收敛速度快、对多普勒频移鲁棒性高等优点.

基于小波奇异特征约束的期望最大时延估计算法

针对低信噪比条件下非平稳信号时延估计精度低的问题,提出基于小波奇异特征约束的期望最大时延估计算法。设计小波奇异性特征尺度广义互相关矩阵,构建多尺度小波奇异特征约束下的期望最大化模型。推导参数更新公式,利用期望最大化算法并行迭代,求取奇异性特征显著性最大条件下信号的自适应尺度以及该尺度下声源信号的最优时延估计值。仿真和实验结果表明,所提算法在低信噪比条件下,相较于传统广义互相关时延估计算法以及改进算法具有较高的时延估计精度,并且有效提高了误差约束范围内的有效估计成功率。

未足月胎膜早破产妇入院期待时间长短的相关因素及对妊娠结局的影响分析

目的:分析未足月胎膜早破产妇入院期待时间长短的相关因素及对妊娠结局的影响。方法:通过回顾性分析2021年1月至2024年1月本院收治的100例未足月胎膜早破产妇病例资料。根据产妇入院期待时间是否超过3天,将其分为两组,分别为<3d组(n=38)和≥3d组(n=62)。对比两组一般资料、临床特征和妊娠结局,研究影响入院期待时间长短相关因素及对妊娠结局的影响。结果:<3d组的孕周、入院时WBC、入院时CRP、宫颈长度<20mm比例、入院宫颈消退80%比例、羊水过少比例和阴道分泌物培养阳性比例与≥3d组间之间存在明显差异(P<0.05);孕周、入院时WBC、入院时CRP、宫颈长度和羊水过少是影响产妇期待时间长短的独立危险因素(均P<0.05);<3d组剖宫产及新生儿重症监护病房发生率显著高于≥3d组(P<0.05),<3d组临床绒毛膜羊膜炎发生率显著低于≥3d组(P<0.05)。结论:孕周、入院时WBC、入院时CRP、宫颈长度<20mm比例、入院宫颈消退80%比例、羊水过少比例和阴道分泌物培养阳性比例均是影响未足月胎膜产妇入院期待时间的危险因素。延长未足月胎膜早破产妇的入院期待时间对其妊娠结局有一定影响,能改善胎儿结局,但增加孕妇并发症的风险。

数字化医疗场景下基于等待的信息设计研究

医疗场景中等待行为的普遍性、时间的不确定性,是影响患者就医体验的重要因素,数字化医疗服务体系的快速发展,为提供更加即时、高效和个性化的医疗信息服务、提升用户就医等待体验带来了可能性。目的以数字化、信息化医疗服务为技术背景,基于用户等待过程中的信息获取需求,探讨等待服务环节的信息结构要素,以支持患者建立明确的等待预期、改善等待体验,为相关信息设计提供参考。方法根据认知心理学的时间知觉理论,结合医疗候诊场景下的排队特点,将建立明确等待期望转化为时间定位问题,提出基于等待的信息构成要素模型,并通过不同就医阶段场景对不同要素组合的形式有效性和用户满意度进行验证。结果提出基于等待的信息构成模型由时序信息、时距信息、时点信息、时变信息四类信息要素组成,并提出完整的四要素组合设计方案能够同时满足用户不同场景下预判等待时间的信息需求,验证了四要素信息模型的有效性。结论基于医疗等待场景的信息设计要素模型及其组合方案设计研究,能够支持用户建立明确的等待时间预期,并能为其他等待相关场景下的信息设计提供参考框架。

Research on Time Synchronization Method Under Arbitrary Network Delay in Wireless Sensor Networks

To cope with the arbitrariness of the network delays,a novel method,referred to as the composite particle filter approach based on variational Bayesian(VB-CPF),is proposed herein to estimate the clock skew and clock offset in wireless sensor networks.VB-CPF is an improvement of the Gaussian mixture kalman particle filter(GMKPF)algorithm.In GMKPF,Expectation-Maximization(EM)algorithm needs to determine the number of mixture components in advance,and it is easy to generate overfitting and underfitting.Variational Bayesian EM(VB-EM)algorithm is introduced in this paper to determine the number of mixture components adaptively according to the observations.Moreover,to solve the problem of data packet loss caused by unreliable links,we propose a robust time synchronization(RTS)method in this paper.RTS establishes an autoregressive model for clock skew,and calculates the clock parameters based on the established autoregressive model in case of packet loss.The final simulation results illustrate that VB-CPF yields much more accurate results relative to GMKPF when the network delays are modeled in terms of an asymmetric Gaussian distribution.Moreover,RTS shows good robustness to the continuous and random dropout of time messages.

Real-time reliability evaluation based on damaged measurement degradation data

A method was proposed to evaluate the real-time reliability for a single product based on damaged measurement degradation data.Most researches on degradation analysis often assumed that the measurement process did not have any impact on the product's performance.However,in some cases,the measurement process may exert extra stress on products being measured.To obtain trustful results in such a situation,a new degradation model was derived.Then,by fusing the prior information of product and its own on-line degradation data,the real-time reliability was evaluated on the basis of Bayesian formula.To make the proposed method more practical,a procedure based on expectation maximization (EM) algorithm was presented to estimate the unknown parameters.Finally,the performance of the proposed method was illustrated by a simulation study.The results show that ignoring the influence of the damaged measurement process can lead to biased evaluation results,if the damaged measurement process is involved.

Research on Adjust Time of Premium

By considering economic strength and economic profit of insurance company, this paper presents a concept-contact point, and gives premium expectation adjust-time model which provides more practical significance for insurance company to make rational adjustment of premium. Finally, an illustration is given to show their application.

Nonlinear System Identification with Unknown Piecewise Time-Varying Delay

Identification of nonlinear systems with unknown piecewise time-varying delay is concerned in this paper.Multiple auto regressive exogenous(ARX) models are identified at different process operating points,and the complete dynamics of the nonlinear system is represented by using a combination of a normalized exponential function as the probability density function with each of the local models.The parameters of the local ARX models and the exponential functions as well as the unknown piecewise time-varying delays are estimated simultaneously under the framework of the expectation maximization(EM) algorithm.A simulation example is applied to demonstrating the proposed identification method.

接受美学视角下归化、异化策略的选用——Somewhere in Time两译本浅析

自接受美学理论广泛运用在翻译研究之后,读者的期待视野也常用来作为衡量译本优劣的一个标准。通过理查德·麦瑟森的科幻小说《时光倒流》史国强译本和陈宗琛译本的比较,从接受美学的角度研究归化、异化等不同翻译策略对文本风格和读者阅读的影响。从文本细节的具体比较可以看出,史译本更多地采用异化策略,而陈译本更多地采用归化与异化相结合的策略。不同的翻译策略,让两种译本呈现出了不同的风格,而不同策略的译本对读者期待视野的满足也是不同的。

Joint channel estimation and symbol detection for space-time block code

The simplified joint channel estimation and symbol detection based on the EM (expectation-maximization) algorithm for space-time block code (STBC) are proposed. By assuming channel to be invariant within only one STBC word and utilizing the orthogonal structure of STBC, the computational complexity and cost of this algorithm are both very low, so it is very suitable to implementation in real systems.

基于威布尔分布的机械加速寿命试验优化与可靠性统计分析

机电产品加速寿命试验中存在试验效率不高,且试验数据有效性较低的问题,为此,对基于威布尔分布型机械产品恒定应力加速寿命试验进行了优化设计方面的研究。首先,假定威布尔分布型试验样品在各试验应力水平下失效机理保持不变,且其特征寿命与各试验应力水平之间符合广义对数线性方程,在此基础上建立了定时截尾恒定应力加速寿命试验可靠性统计模型;然后,在试验样本总量保持一定的情况下,以各应力水平下的试样分配比例及试验应力水平数为优化变量,同时根据D-最优设计理论,以“各试验应力下得到的Fisher信息矩阵最大,且机械产品中位寿命估计值的方差最小”为优化目标,对威布尔分布型机械产品定时截尾恒定应力加速寿命试验方案进行了优化设计;最后,以某型机械产品为例进行了仿真模拟试验与算例分析,以验证加速寿命试验优化方法的有效性与可行性。研究结果表明:所提出的定时截尾恒定应力加速寿命试验优化设计方法是可行和有效的。

Asymptotic Evaluations of the Stability Index for a Markov Control Process with the Expected Total Discounted Reward Criterion

In this work, for a control consumption-investment process with the discounted reward optimization criteria, a numerical estimate of the stability index is made. Using explicit formulas for the optimal stationary policies and for the value functions, the stability index is explicitly calculated and through statistical techniques its asymptotic behavior is investigated (using numerical experiments) when the discount coefficient approaches 1. The results obtained define the conditions under which an approximate optimal stationary policy can be used to control the original process.

Stochastic Modeling and Power Control of Time-Varying Wireless Communication Networks

Wireless networks are characterized by nodes mobility, which makes the propagation environment time-varying and subject to fading. As a consequence, the statistical characteristics of the received signal vary continuously, giving rise to a Doppler power spectral density (DPSD) that varies from one observation instant to the next. This paper is concerned with dynamical modeling of time-varying wireless fading channels, their estimation and parameter identification, and optimal power control from received signal measurement data. The wireless channel is characterized using a stochastic state-space form and derived by approximating the time-varying DPSD of the channel. The expected maximization and Kalman filter are employed to recursively identify and estimate the channel parameters and states, respectively, from online received signal strength measured data. Moreover, we investigate a centralized optimal power control algorithm based on predictable strategies and employing the estimated channel parameters and states. The proposed models together with the estimation and power control algorithms are tested using experimental measurement data and the results are presented.

模糊厌恶下安全区域内的最优投资再保险策略

文章考虑了模糊厌恶型保险公司的鲁棒最优投资再保险策略问题.假设保险公司以安全区域内达到给定水平κ(≥u s)的期望时间最小化为目标,保险公司可以投资和购买比例再保险,通过动态规划方法,根据随机控制原理建立相应的HJBI方程,得到最优鲁棒投资再保险策略和相应的值函数的解析解.最后分析了模糊厌恶参数对最优策略和值函数的影响.

预期寿命延长条件下自我人力资本投资对生育数量的挤出效应

我国生育政策调整并未产生预期效果的原因之一是人均预期寿命延长引致父代自我人力资本投资收益增加,进而使家庭生育数量决策面临内生性压力。在成年人预期寿命持续提高的条件下,用时间度量家庭生育抚养孩子的投入,呈现不同人力资本存量父代的生育抚养成本差异,研究父代的自我人力资本投资对家庭生育数量的挤出效应。而后,利用CHARLS数据,兼顾生育政策执行的时间与地域差异,检验父代自我人力资本投资对家庭生育数量的影响。实证发现,即使剔除生育质量对生育数量的替代作用,父代教育投入增加仍对家庭生育数量有挤出效应,特别是母亲的自我人力资本投资对家庭生育数量的挤出效应更强。这意味着家庭生育数量的主要抑制性因素已不再是生育政策,预期寿命延长引致的自我人力资本投资收益增加才是家庭生育数量下降的关键。所以,可通过调整生育抚养时间、延长工作年限来缓解挤出效应。

编码后奖赏影响基于议程的学习:奖赏预期和结果的作用

基于ABR模型考察奖赏预期和奖赏结果对不同难度词对记忆与元记忆的影响。结果发现:(1)限时学习条件下,奖赏结果促进不同难度词对记忆成绩和学习判断,奖赏预期仅提高简单词对的记忆成绩。(2)自定步调学习条件下,定时学习判断时奖赏结果仅影响学习判断;奖赏预期促进高难度词对的学习时间分配,从而提高记忆成绩和学习判断。(3)在自定步调学习时,奖赏预期超越难度成为影响学习时间分配的因素。以上结果表明,个体会综合奖赏预期、奖赏结果和难度构建学习议程,足够大的奖赏预期会超越难度成为议程构建的主导因素。但奖赏预期和奖赏结果对记忆成绩、学习时间分配和学习判断的影响受学习条件调节。

主导国和崛起国的时间认知及其影响

文章分析主导国和崛起国的时间认知如何影响权力转移。文章假定,国家仍然是国际关系的主要行为体;权力转移发生在国际体系大国之间;权力转移中的主导国和崛起国都要考虑时间问题,并在时间认知中规划、调整自身的行为。文章认为,主导国和崛起国对时段的预期和时机的认知,在很大程度上决定了它们之间的互动及其结果。时段预期是指主导国和崛起国认为完成权力转移需要多长时间的主观预期,它决定国家选择冲突战略还是竞争战略,并在此基础上确定战略优先和战略手段;时机考验主导国和崛起国认识与处理时段内“危”与“机”的方式,时机认知决定国家战略稳定还是战略调整。文章以英美权力转移和英德权力转移为案例,对时间认知在转移过程中所起到的作用进行探究,进一步论证了时间认知在权力转移中的作用。