关于我国新一轮环保科技体制改革的若干思考

作为科技体制的部门延伸,环保科技体制是促进环保科技发展、应对我国严峻环境问题的重要条件和保障。本文通过问卷调查,剖析了我国当前环保科技体制存在的主要问题及产生原因,并为新一轮环保科技体制改革的启动提供了相应的政策建议。     

公司跨界经营、信息披露与分析师预测

通过手工搜集2003-2017年公司跨界经营数据,本文检验了公司跨界经营对分析师盈利预测的影响及其市场后果.实证结果表明,随着公司跨界程度的提高,分析师对其盈利预测的准确性下降,预测报告发布频率和预测修正幅度则会提高.同时,公司信息披露质量的提升有助于缓解公司跨界经营对分析师预测行为带来的不利影响.上述结果支持了信息处理成本假说和信息不确定性假说.最后,本文对跨界经营的市场后果做了检验,结果发现公司跨界经营程度越高,对分析师预测行为产生的消极作用越大,公司的市场折价程度越高.     

New rapid transfer alignment method for SINS of airborne weapon systems

Transfer alignment is an effective alignment method for the strapdown inertial navigation system （SINS） of airborne weapon systems. The traditional transfer alignment methods for large misalignment angles alignment use nonlinear transfer align- ment models and incorporate nonlinear filtering. A rapid transfer alignment method with linear models and linear filtering for ar- bitrary misalignment angles is presented. Through the attitude quaternion decomposition, the purpose of transfer alignment is converted to estimate a constant quaternion. Employing special manipulations on measurement equation, velocity and attitude linear measurement equations are derived. Then the linear trans- fer alignment model for arbitrary misalignment angles is built. An adaptive Kalman filter is developed to handle modeling errors of the measurement noise statistics. Simulation results show feasibili- ty and effectiveness of the proposed method, which provides an alternative rapid transfer alignment method for airborne weapons.     

Angular glint calculation and analysis of radar targets via adaptive cross approximation algorithm

Angular glint is a significant electromagnetic （EM） scattering signature of extended radar targets. Based on the adaptive cross approximation （ACA） algorithm accelerated method of moments （MoM） and the plane incident wave assumption, the narrowband, wideband and newly developed high-resolution range profile （HRRP） based angular glint calculation formulations are derived and applied to arbitrarily shaped three-dimensional （3D） perfectly electrical y conducting （PEC） objects. In addition, the near-field angular glint is emphasized, which is of great importance for radarseeker applications. Furthermore, with the HRRP based angular glint, an approach to rigorously determine range resolution cel s which own relatively smal er angular glint is provided. Numerical results are presented with new findings to demonstrate the usefulness of the developed formulations.     

平顺移动模式下考虑加工时间与调整时间可分离的多目标流水车间批量调度

对平行顺序移动模式下考虑加工时间与调整时间可分离的多目标流水车间批量调度问题展开研究.构建以加工制造设备总停机次数、批量工件生产周期以及搬运批量工件的总次数为决策目标的基于分层序列法的多目标决策模型,利用该模型可确定批量工件的最优加工排序方案.建立平行顺序移动模式的加工与调整时间模型,该模型是求解生产周期的基础,也是为批量工件的最优调度方案制定生产作业计划的依据.提出并设计平行顺序移动模式下考虑加工时间与调整时间可分离的禁忌搜索算法对问题进行求解.研究结果表明:本研究可为平顺移动模式下考虑加工时间与调整时间可分离的批量生产流水车间选出批量工件的最优调度方案,同时可为批量工件的加工和加工制造设备的调整制定精确的生产作业计划.     

动态抗饱和平滑切换控制器设计方法

针对一类受饱和约束的切换系统,提出了一种动态抗饱和平滑切换控制器的设计方法。首先,基于模型依赖平均驻留时间的方法设计了平滑切换控制器,能够确保系统全局一致渐进稳定并具有一定的鲁棒性能。同时,通过引入链式切换律降低控制器设计的保守性。在此基础上,给出动态抗饱和补偿器的设计方法。将动态抗饱和补偿器设计问题转化为受线性矩阵不等式组约束的优化问题。以航天器在轨加注过程姿态控制系统为例,建立了该系统的链式平滑切换模型,上述模型能够更加准确地反映系统转动惯量的渐变特性。最后,数值仿真算例表明了所提出的控制器设计方法的有效性。     

Self-alignment of full skewed RSINS：observability analysis and full-observable Kalman filter

Traditional orthogonal strapdown inertial navigation sys-tem （SINS） cannot achieve satisfactory self-alignment accuracy in the stationary base： taking more than 5 minutes and al the iner-tial sensors biases cannot get ful observability except the up-axis accelerometer. However, the ful skewed redundant SINS （RSINS） can not only enhance the reliability of the system, but also improve the accuracy of the system, such as the initial alignment. Firstly, the observability of the system state includes attitude errors and al the inertial sensors biases are analyzed with the global perspective method： any three gyroscopes and three accelerometers can be assembled into an independent subordinate SINS （sub-SINS）;the system state can be uniquely confirmed by the coupling connec-tions of al the sub-SINSs;the attitude errors and random constant biases of al the inertial sensors are observable. However, the ran-dom noises of the inertial sensors are not taken into account in the above analyzing process. Secondly, the ful-observable Kalman filter which can be applied to the actual RSINS containing random noises is established; the system state includes the position, ve-locity, attitude errors of al the sub-SINSs and the random constant biases of the redundant inertial sensors. At last, the initial self-alignment process of a typical four-redundancy ful skewed RSINS is simulated： the horizontal attitudes （pitch, rol ） errors and yaw error can be exactly evaluated within 80 s and 100 s respectively, while the random constant biases of gyroscopes and accelero-meters can be precisely evaluated within 120 s. For the ful skewed RSINS, the self-alignment accuracy is greatly improved, mean-while the self-alignment time is widely shortened.     

5G移动通信发展趋势与若干关键技术

第5代移动通信系统(5G)是面向2020年之后的新一代移动通信系统,其技术发展尚处于探索阶段.结合国内外移动通信发展的最新趋势,本文对5G移动通信发展的基本需求、技术特点与可能发展途径进行了展望,并分无线传输和无线网络两个部分,重点论述了富有发展前景的7项5G移动通信关键技术,包括大规模天线阵列、基于滤波器组的多载波技术、全双工复用、超密集网络、自组织网络、软件定义网络及内容分发网络.本文还概括性地介绍了国内5G移动通信的相关研发活动及其近期发展目标.     

用于异质用户出行管理的可交易许可证研究

针对公共交通与私家车出行方式并行的双模式交通系统,在考虑不同用户的时间价值情况下,通过引进可交易的道路许可证政策,建立了均衡出行交通模型.研究发现,许可证政策将拥挤产生的交通成本内部化,在缓解交通拥堵的同时,通过经济手段,降低了系统总成本.进一步地,本文证明如果汽车比公交快,那么时间价值较高的人会选择私家车出行;反之,如果公交比汽车快,时间价值相对较高的有车族会选择公交出行.通过与OD收费进行比较,我们得到在收费为正的情况下,许可证政策可以得到与基于OD收费相同的效果.最后,算例结果表明,许可证政策使得部分人选择公交出行的成本更低,达到鼓励公交出行的目的;甚至在许可证发放数量少于临界数量的情况下,选择公交出行的人会获得正收益.