On the static H∞ control problem

The problem of existence of static controller in standard H_∞ control problem or, equivalently, solvability of a couple of Riccati inequalities with respect to the same Hermitian matrix is reduced to solvability of a single Riccati inequality. This inequality is presented in a form which is bilinear with respect to unknown parameters. In a special case the inequality is transformed to LMI.     

安全Linux内核安全功能的设计与实现

CC标准是一个新的国际标准,由于缺乏可借鉴的范例,开发符合CC标准 的安全操作系统是一项挑战性的工作。借助一项研究实验结合中国安全保护等级划分准则等3条款,讨论了安全Linux内核安全功能在CC框架下的设计与实现问题,通过CC功能需求组件给出安全功能的定义,从系统结构和安全模型方面讨论安全功能的实现方法,并测算安全机制产生的性能负面影响。研究表明,中国国家标准的要求可以通过CC标准进行描述。最后,还指出了安全操作系统进一步的研究方向。     

中国城市化量化指标的综合思考

研究和探索城市化发展最本质的量化指标问题,认为城镇化的度量决不是惟一的单因子,必须利用多种标准复合因子进行研究,提出中国城市划分的新方案。     

Market-clearing for pricing system security based on voltage stability criteria

This paper presents a novel technique for representing system security in the operation of decentralized electricity markets, with special emphasis on voltage stability. The market-clearing algorithm is modeled as voltage stability constrained-optimal power flow (VSC-OPF) problem for providing market solutions by means of a function of complying with the required voltage stability criteria. Benders’ decomposition is applied for solving the VSC-OPF incorporating post-contingency control actions, which is motivated by the improvement of computational efficiency using parallel processing. The proposed VSC-OPF framework also takes into consideration the bilateral contract information, which is integrated into the market-clearing process and, at the same time, the optimal pricing expressions through computing local marginal prices (LMPs) with respect to ensuring voltage stability are derived. VSC-OPF is tested on the IEEE 14-bus benchmark system and the results obtained, when compared to those obtained by means of a conventional OPF, show that the proposed technique is able to improve system security while yielding better market solutions and total transaction levels.     

The effects of oil prices on inflation, interest rates and money

Recently, most of the relevant studies (see, e.g. Atukeren [5], Ayadi [6], Roeger [38], Trehan [44], Bermingham [7], Oladosu [34]) have focused on oil price shocks to the economy variables such as GDP, interest rates, inflation, and industrial production, but few studies have focused on external shocks to the possible reaction of monetary policies. Thus, this paper includes money variables in empirical models and investigates the relationships among oil prices, inflation, interest rates and money. The monetary policy might take time to be effective, so the concerns of lag-chosen issues will be vital issues from the aspect of this research. Then, different lag-chosen criteria and symmetric and asymmetric lag-lengths chosen are placed in a stressed situation in this study with regard to monetary lag concerns. We find that the empirical results are quite robust concerning various lag-chosen criteria, symmetric and asymmetric models, and different time series models. So, it implies that monetary policies still matter after accounting for the oil prices, the energetic variable, with the above robustness concerns.     

电网侧储能电站综合评价

对储能系统进行综合评价有助于从整体上全面地把握储能系统的价值,使决策更加全面、合理。针对电网侧储能,提出一套适用性强、可行性高、层次分明的储能价值综合评估指标体系,并对各指标的定义及计算进行了详细说明。进一步给出相适应的综合评价方法,同时对某变电站电网侧储能项目进行实例评估,为后续储能项目规划和建设提供参考。     

基于可能度矩阵的区间型多属性决策方法

研究了几组可能度公式之间的关系,提出一种基于可能度矩阵的区间型多属性决策(MADM)方法。对决策矩阵中各指标下的属性区间值两两比较并建立各指标的可能度矩阵,通过各个可能度矩阵的排序向量把属性值为区间数的决策矩阵转化为以精确数为测度的矩阵,把求解区间型多属性决策中指标权重的不确定性问题转化为确定性问题处理,随后利用区间数排序的可能度法获得最优方案。实验结果表明了所提方法的可行性和有效性。最后对多属性决策问题中由不确定性转化为确定性的求解策略及其可能产生的问题作了必要讨论。     

链式网络中区域备用电源自动投入的风险控制及策略优化

链式供电网络结构大量存在于电力系统中,区域备自投装置凭借在链式网络中电源点故障时能快速恢复供电的优势在现场应用逐渐广泛。文中通过深入分析区域备自投与常规备自投装置在动作逻辑方面的差异,提出区域备自投装置在安装调试、整定计算、运行维护中的风险及相应的控制措施。针对目前区域备自投逻辑控制策略中仅采用母线失压和主供电源线路无电流作为判据的问题,提出新增“本侧开关位置”“联络线对侧有压”两个逻辑判据,有效规避变电站轻负荷且母线PT断线情况下的误动作。最后,结合110 kV草池—十里坝链式网络搭建RTDS仿真系统,对电源点、联络线故障以及断路器偷跳、母线PT断线进行了仿真测试,结果表明,优化后的控制策略能准确定位故障区,快速合上备用电源,减少误动作发生,有效地提高链式网络的供电可靠性。     

基于GCV准则与Otsu法的Canny算子研究

为了增强图像的可读性,解决因光照、噪声等因素造成的图像模糊、边缘不清等问题,在前人研究的基础上提出了对Canny算子的改进.用遗传算法对基于GCV准则的阈值函数自动寻优,在降低噪声的同时增强了图像的可读性;用评价函数对Otsu法自适应设定高低阈值,无需考虑阈值比例,减少了伪边缘现象.不同图像的边缘提取实验和数据分析表明,该方法在检测精度、抗噪能力和运算效率等方面都得到明显提高.对于存在的不足提出了进一步研究方向.     

微型钢丝绳传动绳槽匹配及设计方法研究

微型绳传动是一种新型的精密传动方式,它以简单的形式替代以往复杂的机构,实现高精度,高刚性,低成本的传动,并形成了一整套传动体系。然而其传动特性并没得到普遍认识,其设计理论并不完善。笔者以一种新颖的钢丝绳传动为研究背景,分析了绳传动轴向运动特性,给出了实现正常传动时应满足的绳槽匹配条件,推导了绳传动中钢丝绳偏斜角表达式,并以此作为绳传动的设计准则,通过对实际绳传动系统设计验证了笔者提出设计方法的可行性。