基于Aduc845的数据采集与控制系统

本文设计并实现了一种基于Aduc845微处理器芯片的高精度数据采集与控制系统,主要包括模拟输入,采集,运算,输出控制,以及与计算机通讯等部分,并详细论述了基准信号的提取和采集信号的处理。该系统精度高,可靠性好,功能齐全,可广泛应用于传感器领域。     

Self-regulated learning through writing on computers: Consequences for reading comprehension

The overall aim for the present study was to analyze the consequences for reading ability among the children of a computer supported self-regulated learning environment in grade two. By means of a quasi-experimental design in a natural setting, an experimental group (n = 39) was compared to a control group from a national sample (n = 3409) on reading comprehension. The statistical analyses showed that the experimental group achieved better on reading comprehension both as a group (p < .001) as well as girls (p < .001) and boys (p < .05) separately. The proportion of high achievers was higher, and the proportion of low achievers was lower in the experimental group. In order to explain the level of reading comprehension in the experimental group Structural Equation Modelling (SEM) was used. The main explanatory factor for reading comprehension was writing with β = .44. As a tentative conclusion it was suggested that the extended writing in combination with the self-regulated learning environment can promote reading comprehension in grade two, whereas home literacy had no impact on reading comprehension in this context.     

一种基于L_1范数模型和内点理论的潮流算法

提出一种结合L1范数模型和内点理论的潮流计算方法,利用基于扰动KKT条件的原始-对偶内点算法进行一般潮流问题求解.与以前的最小潮流法相比,该方法简单、求解易于收敛、易于程序实现,便于对病态系统求解,并同时能判断潮流方程是否有解.     

LEAP EFFECTS AMONG ROBUST ROOT TRAJECTORIES

The set of closed-loop eigenvalues in the presence of the worst uncertainty is termed robust root trajectory. The open-loop gain or some other system parameter is changed monotonically. The admissible uncertainties are considered along their envelope. The worst uncertainty is denoted as that one where a specified function of the eigenvalues leads to the maximum disadvantageous effect on the closed-loop stability performance. Leaps in the dynamic behavior occur even for infinitesimally small changes in the gain parameter when system uncertainties are considered that are located especially at their bounds.     

Stability criteria of matrix polynomials

In this paper, the stability of matrix polynomials is investigated. First, upper and lower bounds are derived for the eigenvalues of a matrix polynomial. The bounds are based on the spectral radius and the norms of the related matrices, respectively. Then, by means of the argument principle, stability criteria are presented which are necessary and sufficient conditions for the stability of matrix polynomials. Furthermore, a numerical algorithm is provided for checking the stability of matrix polynomials. Numerical examples are given to illustrate the main results.     

Mixed output feedback of the finite frequency H∞ control for singularly perturbed system

This paper considers the H_∞ control problem for a class of linear singularly perturbed systems in the finite frequency range. A mixed output feedback controller comprising of a static output feedback controller and a dynamic output feedback controller is developed for the system stabilisation. Based on the generalised Kalman–Yakubovich–Popov (GKYP) lemma, the frequency-domain inequalities can be converted into linear matrix inequalities which are numerically tractable. Compared with the existing full frequency approaches, better results are obtained. Moreover, the selection methods of the cut-off frequencies in both low and high frequency ranges are extensively studied with a view to reduce the conservativeness in output feedback control design. Simulation results suggest the asymptotic validity of the main results in this paper.     

THE FORSCHUNGSAMT: NAZI GERMANY'S MOST SECRET COMMUNICATIONS INTELLIGENCE AGENCY

Abstract

The cryptographic hash function Codefish is an outcome of a research project led by the company KRIPTO Research and the University of Debrecen in Hungary and sponsored by the European Union and the Hungarian Government. It is commercialised by KRIPTO Research for use in security protocols like digital signature, authentication, or message checksum. Codefish benefits from strong mathematical foundations, since it grounds its security on the difficulty of solving norm form equations. This paper demonstrates that it is insecure for cryptographic applications by presenting practical attacks for solving the problems Second Preimage and Collision.     

Multivariable norm optimal and parameter optimal iterative learning control: a unified formulation

This article investigates the two paradigms of norm optimal iterative learning control (NOILC) and parameter optimal iterative learning control (POILC) for multivariable (MIMO) ?-input, m-output linear discrete-time systems. The main result is a proof that, despite their algebraic and conceptual differences, they can be unified using linear quadratic multi-parameter optimisation techniques. In particular, whilst POILC has been naturally regarded as an approximation to NOILC, it is shown that the NOILC control law can be generated from a suitable choice of control law parameterisation and objective function in a multi-parameter MIMO POILC problem. The form of this equivalence is used to propose a new general approach to the construction of POILC problems for MIMO systems that approximates the solution of a given NOILC problem. An infinite number of such approximations exist. This great diversity is illustrated by the derivation of new convergent algorithms based on time interval and gradient partition that extend previously published work.     

Optimal time-weighted H 2 model reduction for Markovian jump systems

This article addresses the optimal time-weighted H ₂ model reduction problem for Markovian jump linear systems. That is, for a given mean square stable Markovian jump system, our aim is to find a mean square stable jump system of lower order such that the time-weighted H ₂ norm of the corresponding error system is minimised. The time-weighted H ₂ norm of the system is first defined, and then a computational method is constructed. The computation requires the solution of two sets of recursive Lyapunov-type linear matrix equations associated with the Markovian jump system. To solve the optimal time-weighted H ₂ model reduction problem, we propose a gradient flow method for its solution. A necessary condition for minimality is derived, and a computational procedure is provided to obtain the minimising reduced-order model. The necessary condition generalises the standard result for systems when Markov jumps and the time-weighting term do not appear. Finally, two numerical examples are given to demonstrate the effectiveness of the proposed approach.