基于杠杆法的4T65E自动变速器传动研究

使用杠杆分析法对4T65E自动变速器的换挡过程中的构件旋转速度和力矩进行了详细直观的分析,并从三个设计角度验证了4T65E自动变速器传动方案设计的合理性;同时对自由轮在此变速箱中的作用作了详细的分析。     

Dynamics of cholera transmission model with imperfect vaccination and demographics on complex networks

Cholera is a waterborne infectious disease that continually emerges and remains an important global health burden. We formulate and investigate a cholera model with imperfect vaccination and demographics on complex networks, in which two transmission pathways, indirect environment-to-human and direct human-to-human transmissions, are incorporated simultaneously. The contacts among humans are treated as a heterogeneous network and the contacts between environment and humans as homogenous mixing. Using the spectral analysis method, the basic reproduction number is defined and verified to be a sharp threshold which completely determines global dynamical properties of model. Numerical simulations are performed to confirm the theoretical results. The results demonstrate that demographics and the degree distribution of the network are of great importance in cholera propagation, and that the degree distribution is time-dependent until the stationary state is reached. Furthermore, demographics have a significant influence on the basic reproduction number. By increasing the vaccination rate and decreasing the rate at which the vaccine wears off, cholera infection can be effectively controlled.     

Performance analysis of a spreading sequence estimator for spread spectrum transmissions

Direct sequence spread spectrum transmissions (DS-SS) are now widely used for secure communications, as well as for multiple access. They have many interesting properties, including low probability of interception. Indeed, DS-SS transmitters use a periodical pseudo-random sequence to modulate the baseband signal before transmission. A receiver which does not know the sequence cannot demodulate the signal.In this paper, we propose a new method which can estimate the spreading sequence in a noncooperative context. The method is based on eigenanalysis techniques. The received signal is divided into windows, from which a covariance matrix is computed. We show that the sequence can be reconstructed from the two first eigenvectors of this matrix, and that useful information, such as desynchronisation time, can be extracted from the eigenvalues.The main achievement of the present paper is a performance analysis of the proposed spreading sequence estimation procedure. An analytical approach is first considered owing to matrix perturbation theory and Wishart matrix properties. Then, complementary Monte Carlo simulations are performed to show the effectiveness of the proposed method.     

浅析液压传动的原理及其在矿井提升系统中的应用

通过对液压传动基本工作原理的分析,阐述了液压传动原理在矿井提升系统中TE130液压站中的应用,体现了它在矿井安全生产中的重要作用。     

Optimal control of gear shift operations in automatic transmissions

An optimal control approach for gear shift operations in automatic transmissions is proposed in this paper. Starting from a verified model of a typical power train with an automatic transmission a performance measure for evaluating the gear shift process in terms of passengers comfort and control expenditure is developed. The gear shift operation is stated as a multistage decision process by making use of the dynamic programming method. Thereby, the synchronization of the gear box is formulated as a constraint at the end of the process. A control law is derived analytically in an explicit form by minimizing the performance measure over each process stage. Simulation results show a significant improvement in terms of gear shift comfort by different driving load cases. Furthermore, the shift time and the frictional losses in the shift elements can be reduced by applying the proposed control.     

移动网络视频传输控制研究

移动网络视频传输控制技术的关键问题是如何避免拥塞,并在丢包存在的情况下尽可能提高视频质量。文章基于无线网络平台,为了保证解码端的正确执行,使用了一些传输控制技术来减少传输错误造成的影响,并基于RTCP／RTP协议研究一些视频传输中的关键问题如误差掩盖、差错控制和速率控制等,针对视频传输中的速率控制问题分析了几种方法和思路。     

A full mean-square analysis of CNSAF algorithm for noncircular inputs

A full performance analysis of complex normalized subband adaptive filter (CNSAF) algorithm will provide guidelines for designing the adaptive filter. However, because of the noncircular characteristic of complex-value signal, the complementary mean-square performance analysis of the CNSAF algorithm has not been presented in the literature. In order to give the detailed theoretical expressions of the CNSAF algorithm, the present study first analyzes the mean-square deviation (MSD) with the energy-conservation method, and then the complementary mean-square derivation (CMSD) behavior is given using pseudo-energy-conservation method. Analytical expressions are obtained for the transient MSD and CMSD of the CNSAF algorithm. Also, the steady-state MSD and CMSD are predicted based on the closed-form expressions. Besides, the analysis results are not constrained by the distribution of input signals. Finally, simulation results obtained for diffferent inputs present a good consistence with the analytical results.     

An investigation of online searcher traits and their relationship to search outcome.

This study investigated more attributes of online searchers that were believed to affect the quality of their search results. Subjects were selected from the online searching courses in six library schools. The searching proficiency of the subjects was measured by their performance on two DIALOG searches. Their creativity level was measured using two self-report inventories; their intelligence level was approximated from their GRE Verbal and Quantitative scores; and their personality traits in regard to masculinity, femininity, and self-esteem were measured using the Interpersonal Disposition Inventory. The large number of independent, predictor variables were reduced by factor analysis and the derived factors were related to the dependent variable, online searching performance, in a multiple regression analysis. The findings suggest that differences in searching performance can be attributed, to a small degree only, to general verbal and quantitative aptitude, artistic creativity, and to an inclination toward critical and analytical creative thinking. The findings also raise doubts, however, that high intelligence and other attributes cited by writers in the field are necessary for high performance. The notion that searching performance can be predicted by or is dependent upon certain cognitive or personality traits has thus become highly suspect.     

工业企业不同类型绿色技术创新内在关联与绩效传导路径

绿色技术创新可划分为末端治理技术创新、绿色工艺创新和绿色产品创新,在改进环境绩效和市场竞争力的同时,也能够提高企业的经济绩效。本文构建了绿色技术创新升级和经济绩效改善的关系模型,以642家工业企业为样本进行实证分析。研究结果表明：①企业3类绿色技术创新均能够显著改善其环境绩效和市场竞争力。②企业环境绩效和市场竞争力是经济绩效传导过程中的重要中介变量。③企业末端治理技术创新能够促进绿色工艺创新和绿色产品创新,企业绿色工艺创新能够正向影响企业的绿色产品创新,即不同类型绿色技术创新之间存在技术创新升级的空间。④不同类型绿色技术创新向经济绩效传导的路径存在一定的差异性,表现为绿色工艺创新能够直接产生经济绩效,而末端治理技术创新、绿色产品创新只能通过间接路径提高企业的经济绩效。通过上述研究识别了企业3种不同类型绿色技术创新之间的传导关系,对比分析了不同类型绿色技术创新经济绩效提升的异同性,给出了更多的企业绿色技术创新经济绩效提升的路径,对于深化绿色技术创新过程认识及优化政策设计具有重要意义。     

基于芯片控制的煤矿数控液压站的设计与仿真

液压站是煤矿生产过程中应用最为广泛的设备之一,其性能的好坏直接影响着矿井的安全运转以及正常生产。本文通过对基于芯片控制的煤矿数控液压站进行数学建模,以更加直观的图形对液压站工作过程中各个元件的性能、参数以及对整个系统的影响进行仿真分析,找出影响数控液压站工作的主要因素并且进行改进和升级,进一步优化数控液压站的结构,为煤矿生产提供更加安全、可靠的保证。     

基于组织公平的变革型领导行为与组织公民权行为关系的实证研究

本文编制了结构化的企业员工组织公民权行为、组织公平和领导行为的问卷,对几家企业的4000多名员工进行了实地调查。用积极主动维度、组织忠诚和帮助维度来衡量组织公民权行为;用分配公平、互动公平来衡量组织公平;用愿景激励、德行垂范、领导魅力衡量变革型领导行为。分析结果显示,员工个体的差异与组织公民权行为存在相关关系;变革型领导行为的三个维度与组织公民权行为(积极主动、组织忠诚、帮助行为)、组织公平(分配公平、互动公平)都具有显著的关系;还发现组织公平与组织公民权行为之间的积极关系。分析结果证实了组织公平对变革型领导行为与组织公民权行为关系的调节作用。构建了变革型领导行为影响组织公民权行为的理论框架。最后指出了本次研究的一些局限以及就将来研究的一些方向给出一些建议。     

Extended-state-observer-based output feedback adaptive control of hydraulic system with continuous friction compensation

This paper presents an extended state observer-based output feedback adaptive controller with a continuous LuGre friction compensation for a hydraulic servo control system. A continuous approximation of the LuGre friction model is employed, which preserves the main physical characteristics of the original model without increasing the complexity of the system stability analysis. By this way, continuous friction compensation is used to eliminate the majority of nonlinear dynamics in hydraulic servo system. Besides, with the development of a new parameter adaption law, the problems of parametric uncertainties are overcome so that more accurate friction compensation is realized. For another, the developed adaption law is driven by tracking errors and observation errors simultaneously. Thus, the burden of extended state observer to solve the remaining uncertainties is alleviated greatly and high gain feedback is avoided, which means better tracking performance and robustness are achieved. The designed controller handles not only matched uncertainties but also unmatched dynamics with requiring little system information, more importantly, it is based on output feedback method, in other words, the synthesized controller only relies on input signal and position output signal of the system, which greatly reduces the effects caused by signal pollution, measurement noise and other unexpected dynamics. Lyapunov-based analysis has proved this strategy presents a prescribed tracking transient performance and final tracking accuracy while obtaining asymptotic tracking performance in the presence of parametric uncertainties only. Finally, comparative experiments are conducted on a hydraulic servo platform to verify the high tracking performance of the proposed control strategy.     

地位竞争视角下员工主动性行为与创新绩效的关系研究

本研究基于领导-成员交换理论和社会支配理论,在等级制度和高权力距离的中国文化背景下,从地位竞争视角出发研究员工主动性行为、领导-成员交换关系、领导地位威胁感知与个体创新绩效之间的关系。基于13个组织的630套上下级配对问卷数据,采用层级线性回归模型对假设进行检验,本研究发现员工主动性行为正向影响其创新绩效,领导-成员交换关系中介了二者之间的正向关系,领导地位威胁感知削弱了员工主动性行为与创新绩效、员工主动性行为与领导-成员交换关系之间的正向关系。研究结果为员工主动性行为的研究提供了新的视角和框架,同时对企业管理实践有一定的现实意义。     

国际化行为对高新技术企业创新绩效的影响机理——基于吸收能力的中介效应

国际化已成为新兴经济体国家实现创新追赶的重要战略选择。本文利用2014-2016年879家高新技术企业相关数据,针对企业多种国际化行为对创新绩效的影响进行理论分析与实证检验。并突破传统资源观和学习观,验证企业吸收能力在国际化行为与创新绩效间的中介作用及研发投入的调节作用。结果表明：1.国际化行为显著促进企业创新绩效提升,其中海外人才促进效果最强,海外出口次之,海外研发最弱。2.企业吸收能力在部分国际化行为与创新绩效间存在中介作用。3.研发投入在不同国际化行为与吸收能力间均存在调节作用,效果不同。     

绩效反馈还是审时度势：企业研发搜索行为的策略选择研究

随着互联网、5G等新一代信息技术的迅猛发展,企业需要跨越组织边界,通过研发搜索行为捕捉创新机会、激发创新灵感、培养新技能从而提升企业的创新能力,但研发搜索行为是问题使然还是预知先知是企业研发中的一个重要的战略问题。本文基于组织行为理论,系统研究了绩效反馈、审时度势以及在联盟惯例的调节下,他们对企业研发搜索行为选择的影响。研究发现：当绩效反馈低于期望值时,企业会加强研发搜索;当绩效反馈高于期望值时,企业会减少研发搜索;当决策者预期未来绩效高于未来期望值时,企业会减少研发搜索。当绩效反馈低于期望值和预期未来绩效优于未来期望绩效时,联盟惯例在其中发挥负向的调节作用,但是当绩效反馈高于期望值时,联盟惯例强化了企业的搜索行为。研究结论对指导企业进行研发搜索行为的策略选择,有效利用外部资源,推动企业创新,提升企业核心竞争力具有重要的理论和实践意义。     

本土企业转型突破与网络关系升级:基于广告为调节变量的实证研究

在本土企业转型升级行为与升级路径遇到"瓶颈"的背景下,本研究提出了网络关系升级的概念,构建了基于网络关系为中介变量和广告行为为调节变量的企业销售行为和市场行为对企业绩效的影响模型。同时,针对近200家企业搜集了183份有效问卷,进行了实证分析。研究结果表明,网络关系在企业销售和市场行为与企业绩效关系中发挥中介效应;同时,广告行为能显著增强企业的销售和市场行为对网络关系的影响。     

一种工程机械液力传动油的研制

针对工程机械的液力变矩器在低温条件下顺利起动及正常工作,通过采用加氢基础油、中性油和合成烃复合作为基础油,配以具有剪切稳定指数好、良好低温性能的各种添加剂,研制出具有闪点高、倾点低、粘度指数高等优良性能的工程机械液力传动油。其综合性能优于进口产品,其宽使用温度范围尤其突出。     

风险投资网络社群信息传播对投资绩效的影响

信息传播有利于风险投资克服信息不对称性和项目不确定性等关键问题,对风险投资网络社群具有重要意义。利用2000至2015年CVsource数据库中风险投资数据,本文研究风险投资网络社群信息传播对投资绩效的影响及其机理。研究发现,风险投资网络社群信息传播对投资绩效有显著影响,具体表现为项目信息传播对投资绩效呈先增后减的倒U型影响,经验信息传播对投资绩效呈显著正向影响。知识获取分别在项目信息传播和经验信息传播与投资绩效的关系中具有部分中介作用。另外,吸收能力显著负向调节知识获取对投资绩效的正向影响。上述结果意味着,信息传播不仅可以直接作用于投资绩效,而且可以通过知识获取及吸收能力对投资绩效产生间接作用。利用一个社会网络的分析框架,本文论证了信息传播对风险投资绩效的影响机理,并且为风险投资网络社群行为优化以及投资绩效提升提供了经验证据。     

新能源汽车政策效应：规模抑或创新中介？

中国新能源汽车产业补贴政策初衷是激励企业通过研发创新形成全球竞争力，结果却短期内促进了产业规模的快速提升，企业研发投入积极性反而严重不足。现有研究认识到企业行为会影响政策传导效用，但未从政策作用点与传导路径视角深入剖析政策对于企业行为的影响。本文综合运用内容分析法与Bootstrap中介效应模型，将文本分析与实证有机结合到一起，纳入企业规模与企业专利行为作为中介变量，分两条路径对二者的不同作用进行了对比分析。实证研究结果表明：政府支持显著促进了企业绩效、规模与专利产出的提升，且企业规模与专利行为在政策对绩效影响中存在显著的中介作用，其中企业规模的中介效用强于专利行为。新能源汽车双积分等新补贴政策应综合考虑制度、补贴工具及产业特征等因素影响，避免政策在“政府-企业界面”产生偏移。     

整合共享型人力资源实践与团队创新绩效——团队跨界行为与包容型领导的作用

面对日益VUCA的竞争环境,创新成为组织生存发展的现实选择,而团队是组织正常运作的基本单元,团队创新是组织目标实现与竞争优势维系的重中之重,而跨界整合的移动互联时代,团队仅靠自身资源难以应对,因而如何获取外部资源、开发内部资源与整合内外资源成为团队创新的关键,而跨界行为是团队资源外部获取、内部开发与内外整合的可行选择,因而如何通过跨界行为提升团队创新已然成为业界实践与学界研究亟待解决的问题。基于此,本研究以资源依赖理论为基础,旨在探究团队实施的整合共享型人力资源实践（IS-HRP）对团队创新绩效的影响机制与边界条件。基于312份团队领导样本纵向追踪的实证研究发现：（1）IS-HRP与团队创新绩效显著正相关;（2）团队跨界行为在IS-HRP与团队创新绩效影响间有中介作用;（3）包容型领导正向调节IS-HRP与团队创新绩效间关系以及团队跨界行为与团队创新绩效间关系;（4）包容型领导调节IS-HRP通过跨界行为对团队创新绩效的间接作用,包容型领导水平越高,其间接作用越强。从而为团队创新绩效提升的管理实践、领导风格与团队行为提供了理论依据与决策借鉴。