Moment matching model reduction for negative imaginary systems

In this paper, moment matching model reduction problem for negative imaginary systems is considered. For a given negative imaginary system with poles at the origin, our goal is to find a reduced-order negative imaginary system such that a prescribed number of the moments and the poles at the origin are preserved. Firstly, the original negative imaginary system is split into an asymptotically stable subsystem, a lossless negative imaginary subsystem and an average subsystem. Then, moment matching model reduction is implemented on the asymptotically stable subsystem and the lossless negative imaginary subsystem. The resulting reduced-order system preserves the negative imaginary structure and the poles at the origin. Also, the proposed model reduction method is extended to the positive real systems. Numerical examples demonstrate the effectiveness of the proposed model reduction method.     

Communicating citizenship in China’s digital society

ABSTRACT

This research explores the (inter-) cultural dimension of communicating citizenship in China’s new media environment. It adopts speech codes theory as a theoretical and methodological framework to examine the historically situated and socially constructed meanings of citizenship and the normative communicative conduct for practicing “good citizenship” in China. Through a systematic analysis of Chinese online discourse surrounding two social events, this study captures one speech code pertaining to communicating citizenship that is premised on a paradox – citizenship is interpreted by the Chinese as a legal entitlement that they deserve, but it is simultaneously treated as an aspirational and unattainable ideal. Additionally, speaking sensibly and morally with a communal orientation is heavily emphasized in this speech code as it is considered a valuable communicative practice for performing “good citizenship.” Finally, participating in online collective actions such as “topping posts” is rendered an acceptable and effective way to communicate and enact citizen rights in China.     

Bio-inspired untethered fully soft robots in liquid actuated by induced energy gradients

Soft robotics with new designs, fabrication technologies and control strategies inspired by nature have been totally changing our view on robotics. To fully exploit their potential in practical applications, untethered designs are preferred in implementation. However, hindered by the limited thermal/mechanical performance of soft materials, it has been always challenging for researchers to implement untethered solutions, which generally involve rigid forms of high energy-density power sources or high energy-density processes. A number of insects in nature, such as rove beetles, can gain a burst of kinetic energy from the induced surface-energy gradient on water to return to their familiar habitats, which is generally known as Marangoni propulsion. Inspired by such a behavior, we report the agile untethered mobility of a fully soft robot in liquid based on induced energy gradients and also develop corresponding fabrication and maneuvering strategies. The robot can reach a speed of 5.5 body lengths per second, which is 7-fold more than the best reported, 0.69 (body length per second), in the previous work on untethered soft robots in liquid by far. Further controlling the robots, we demonstrate a soft-robot swarm that can approach a target simultaneously to assure a hit with high accuracy. Without employing any high energy-density power sources or processes, our robot exhibits many attractive merits, such as quietness, no mechanical wear, no thermal fatigue, invisibility and ease of robot fabrication, which may potentially impact many fields in the future.     

我国地面气温格点化数据集的研制

在大气科学研究领域,特别是气候变化检测和数值模拟研究中,与高精度、高时空分辨率的格点资料相比,离散的站点观测资料具有明显的优势.随着国家气象科学数据共享工作的纵深开展,站点资料已不能完全满足用户的需求,通过空间插值技术进行格点化气象要素数据集的研制和服务日益迫切.本文结合国家气象信息中心最新研制的中国地面气温格点数据集,对数据集研制过程中的几个关键技术问题及数据集验证情况进行了阐述.     

舟山市教师资源配置非均衡发展:现状、对策与实证

调查证实,舟山市优质教师资源配置城乡差距显著,主要表现在教师学历结构、职称结构和骨干教师分布三个方面.本文提出在信息时代,以信息技术促进教师资源配置城乡一体化均衡发展的整体方案,即城市(或乡下)教师在对本校学生实施面对面教学的同时,可以足不出户通过网络对乡下(或城市)学生实施非面对面的网络教学,从而实现网络时代的教师资源配置城乡一体化均衡发展.     

质数与合数

如果我们按整数正约数个数的不同来考虑正整数的分类．那么有如下三类：     

红军长征过云南与云南民族关系述论

本对红军长征过云南的民族政策及对云南民族关系的影响作了探讨，指出研究红军长征过云南的民族政策和民族关系，对今天提高广大干部群众的民族政策理论水平，对正确执行民族政策，妥善处理云南复杂而多样的民族关系，具有极大的现实意义。     

中国股市走势与经济发展同向异动分析

中国股市与改革同步发展,国民经济同向运行，但股市波动明显异波动明显异动于宏观经济高速发展的轨道，常以暴涨曝跌、长熊短牛的方式演绎非规范市的个性。究其原因，是“政治市”与“投机市”及上市公司品质普通不佳所致。要解决中国股市的异动问题，必须要使股市定位由单纯为国企改革服务转向为全国经济服务，用市场方式促使股市由政策市向功能`市由投机市向投资市转化。     

论黄庭坚的拗体七律

黄庭坚的拗体七律是其成就较高的体裁，但学界对其关注不够，并且对于拗体的界定也众说纷纭。笔者采用王力的七律标准，认为黄庭坚的拗体七律只有31首，并具有如下特点：（1）拗句三句到八句不等；（2）平收类的拗句种类和数量大大多于仄收类，且都和古体诗声律相近。其成因有以下几个方面：（1）对专名的妥协；（2）对对仗的妥协；（3）有意为“拗”，追求奇峭美。